Research ArticleWear and Friction Evaluation of Different Tool Steels forHot Stamping

Maider Muro1 Garikoitz Artola1 Anton Gorrintildeo2 and Carlos Angulo 2

1Metallurgy Research Centre IK4 AZTERLAN Aliendalde Auzunea 6 48200 Durango Spain2Department of Mechanical Engineering University of the Basque Country (UPVEHU)Plaza Ingeniero Torres Quevedo 1 48013 Bilbao Spain

Correspondence should be addressed to Carlos Angulo carlosanguloehues

Received 6 November 2017 Revised 12 February 2018 Accepted 22 February 2018 Published 26 March 2018

Academic Editor Akihiko Kimura

Copyright copy 2018Maider Muro et al (is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

(e aim of this work is to investigate the durability of tool steels for hot stamping by comparing the wear resistance of three hotwork tool steels Friction and wear behaviours of different tool steels sliding against a 22MnB5 uncoated steel at elevatedtemperatures were investigated using a high-temperature version of the Optimol SRV reciprocating friction and wear tester attemperatures of 40 and 200degC Our results show that friction decreased with increasing temperature whereas wear of the tool steelincreased with temperature for the second and the third tested tool steels (e slightly better wear behaviour of steel specimen 1comes from the hardness of the carbides in the martensitic microstructure which are rich in vanadium

1 Introduction

Over the past several years the automotive industry hasexperienced a large growth in the manufacturing ofultrahigh-strength steel (UHSS) components especiallythose who can be processed by means of hot stampingtechnology (is increase is related to improvements ob-tained with these steels in terms of crash resistance and fuelconsumption reduction (e benefits of employing UHSScomponents are accompanied by important technologicalchallenges though since the particularities of the trans-formation of these steels have nothing to do with those ofconventional steels One of the UHSS transformation relatedknowledge areas which is not yet well understood is thetribological interaction between the forming tools and theUHSS parts at high temperatures during the hot stampingprocess In sheet metal forming the wear of tool steelscontinues to be a great concern to the automotive industrybecause of increasing die maintenance costs and scrap ratesCold forming tools are subjected to severe tribologicalstresses due to high contact pressures arising via slidingcontact between the die and the sheet materials (is resultsin high frictional heat generation which affects both the bulk

material and wear properties of the tool steel [1] Since hotstamping tools are subjected to high temperatures the wearof tool steels and the prevailing wear mechanisms have beenstudied in detail [2 3] Several authors have also studiedwear behaviour in friction processes using specific tri-bological tests in order to characterize different tool steelgrades with and without coatings at elevated temperatures[3ndash5]

Understanding the factors that influence the wearmechanisms is necessary to minimize the rate of tool wear inhot stamping (is knowledge could be used to aid toolmaterial selection and die design and hence increase the lifeof die materials used in hot stamping [6 7]

To ameliorate the surface deterioration in hot stampingtools it is necessary to achieve a more in-depth under-standing of wear failure mechanisms [8ndash10] (e wearmechanisms involved in tool damage are determined byfactors that are directly related to the mechanical prop-erties of the materials It is considered that the response towear can be improved by means of structural martensiticchanges [11]

(e purpose of this article is to compare three specimentool steels and assess which behave best against wear during

HindawiAdvances in Materials Science and EngineeringVolume 2018 Article ID 3296398 11 pageshttpsdoiorg10115520183296398

press hardening We interpret our results in the context onthe microstructural features

2 Experimental Procedure

21 Experimental Materials and Specimens (e study andthe comparison of the wear behaviour of three tool steelswere carried out with a tribopair composed of a boron steelwithout coating in annealed condition known as 22MnB5(ferritic-pearlitic microstructure Figure 1) (e chemicalcomposition of 22MnB5 is presented in Table 1

(e tool steels were tested in a hardened condition(quenched and tempered) with a tempered martensiticmicrostructure (e heat treatments applied to the toolsteels are shown in Table 2(e austenitizing and temperingtimes are 30 minutes and 120 minutes respectively (enominal chemical composition of the tool steels (providedby material suppliers) and the final tool hardness are givenin Table 3

(e tool steel specimens were flat disks (Oslash24mm and79mm thick) and were polished to a surface Ra roughnesslevel below 009 microns in order to remove any marks andreduce the number of possible influencing variables duringthe tests (e counter specimens were cylindrical pins(Oslash2mm and 8mm long) flat-end made from 22MnB5 boronsteel (is geometry of the counter specimen was chosenwith the objective of maintaining a constant contact pressureeven if the pin specimen was subjected to high wear

22 Test Equipment (e equipment used in this study wasa reciprocating sliding friction and wear tester SRV model8110 (e SRV machine provided with an electromagneticdrive allows the upper specimens (22MnB5 pins) to os-cillate under normal load against a stationary lower testspecimens (tool steel disks) as shown in Figure 2 (eselected normal load was applied by a servo motor (elower test specimen holder was provided with a heater

Figure 1 Microstructure of the pin is composed of ferrite and pearlite

Table 1 Chemical composition of 22MnB5 (wt)

Material C Si Mn P S Al Cr B22MnB5 024 011 097 0009 0002 0034 025 00046

Table 2 Heat treatment of hot work tool steels

MaterialHardening treatment

Austenitizing (degC) Austenitizing (s) Tempering (degC) Tempering (s)Steel 1 1030 1800 610ndash610 7200Steel 2 1050 1800 510ndash510 7200Steel 3 1040 1800 520ndash520 7200

Table 3 Chemical composition (wt) and hardness of hot work tool steels

Material Mn Cr Mo V C Si Hardness (HRC) Hardness (HV)Steel 1 075 26 225 09 038 03 51 527Steel 2 025 45 30 055 050 02 57 632Steel 3 04 65 13 08 042 05 56 612

2 Advances in Materials Science and Engineering

which permits to condition the test disks at the selectedtemperature 13e SRV tribometer was equipped witha computerized data acquisition and control system so thatthe applied load temperature stroke length and frequencyof the oscillatory movement were controlled and monitored

13e selection of the test parameters was based on typicalhot stamping pressure used in industrial applications13e parameters were a load of 31N a nominal pressure of10MPa a stroke length of 4mm temperatures of 40 and200degC a frequency of 25Hz and duration of 900 s 13e totallength of each test was 90m

23 Test Procedures 13e tests were performed at tempera-tures of 40degC and 200degC Before the tests started all disks andpins were ultrasonically cleaned rst in ether for 5min andthen for 5 more min in acetone After that all specimenswere cleaned with paper and placed in a dryer to eliminate allpossible moisture 13e specimens were held in the dryeruntil the tests started and before the beginning of each testthe specimens were weighted

13e tests started with the heating of the lower specimen(tool steel) to the desired temperature and held for 5min atthat set-point in order to ensure a homogenous temper-ature distribution along the disk 13e upper pin specimenwas kept separated from the disk during the heating se-quence After the disk reached the test temperature andthe 5min dwell time was over the pin was brought intocontact with the disk the load was applied and the test wasperformed

Once the test was nalized each specimen was cleanedagain ultrasonically for 5min in ether and 5 more min inacetone After the cleaning the wear of the disk and pinwas measured 13e measurements of the weight loss of thespecimens were made with a precision weighting scalemodel Mettler Toledo XP205 13e wear volume of the diskswas also measured using a Nikon Eclipse ME600 confocalmicroscope

13e wear scars of the disk and the microstructure wereexamined with an Ultra Plus Zeiss Field Emission Gun-Scanning Electron Microscope (FEG-SEM) and the natureof the carbides in the tool steels was analysed via an Energy-dispersive X-ray Spectroscopy (EDS) analysis

3 Results and Discussion

31 Coecient of Friction During each test the evolution ofthe coecient of friction (COF) with time was recorded asshown in Figures 3 and 4

13e average values of the COF obtained in the tests arepresented in Table 4

When analysing the evolution of the COF with timeduring the test it was observed that the three tool steelshave a similar behaviour at both test temperatures 40degCand 200degC 13ere is no relation between the hardness leveland the COF for the three tool steels and the COFdecreases by around 15 as the test temperature increased

100 200 300 400 500 600 700 800 900

COF

(μ)

Time (s)

Steel 1 40degCSteel 2 40degCSteel 3 40degC

16

14

12

1

0806

04

02

00

Figure 3 COF of the tests performed at 40degC

COF

(μ)

Steel 1 200degCSteel 2 200degCSteel 3 200degC

16

14

12

1

08

06

04

02

00 100 200 300 400 500 600 700 800 900

Time (s)

Figure 4 COF of the tests performed at 200degC

Table 4 Average COF

Material Test temperature (degC) Average COF

Steel 1 40 090plusmn 0005200 080plusmn 0005

Steel 2 40 100plusmn 0005200 090plusmn 0005

Steel 3 40 080plusmn 0005200 070plusmn 0005

Figure 2 Upper and lower specimens in the SRV machine

Advances in Materials Science and Engineering 3

to 200degC 13is tendency was previously observed by othersauthors [3]

32 Wear 13e evolution of the pin wear was measured interms of specimen weight loss For the disks the wearcharacterization was made by quantifying the weight lossand the volume lossincrease with a confocal microscopeFigures 5 and 6 show the specic wear rates of the threetested group of materials (disks and pins)

321 Weight Loss At a temperature of 40degC the pin anddisk weight losses for the tests with steel 2 and steel 3 werelower than the results obtained for steel 113e tests with steel3 stand out because they present the lowest wear in the diskand an intermediate wear on the pin 13is behaviour isrelated with the hardness level of the steel 3 (56HRC)Nevertheless the dicurrenerences in weight loss between the steel2 and steel 3 disks were not large

At a temperature of 200degC the pin wear was lower thanthat at a temperature of 40degC Regarding the disks steel 1 andsteel 2 present similar wear even though their hardness aredicurrenerent that is 51HRC and 57HRC respectively Steel 3showed the highest wear despite its high hardness (56HRC)Nevertheless it is important to emphasise that the wearbehaviour of these three steels at 200degC is similar despitetheir hardness dicurrenerences

A dicurrenerence in behaviour as a function of temperaturewas clearly observed for the three tool steel samples Higherdicurrenerences were observed at 40degC where steel 2 and steel 3presented lower wear in comparison with steel 1 As thetemperature increased to 200degC oxide formation may occurwhich decreases pin wear In contrast as the test temperatureincreased disk wear increased mainly for steel 2 and steel 3

322 Wear Rate In addition to the weight and volumeloss the wear rate of the pins and disks was calculated13e specic wear rate (k) is expressed by

Tool steel 1(51HRC)

Tool steel 2(57HRC)

Tool steel 3(56HRC)

Tool steel 1(51HRC)

Tool steel 2(57HRC)

Tool steel 3(56HRC)

Temperature (degC)40degC 200degC

10E ndash 04

90E ndash 05

80E ndash 05

70E ndash 05

60E ndash 05

50E ndash 05

40E ndash 05

30E ndash 05

20E ndash 05

10E ndash 05

00E + 00

Spec

ific w

ear r

ate (

mm

3 Nm

)

Figure 5 Specic wear rate of the disks at 40degC and 200degC

Tool steel 1(51HRC)

Tool steel 2(57HRC)

Tool steel 3(56HRC)

Tool steel 1(51HRC)

Tool steel 2(57HRC)

Tool steel 3(56HRC)

Temperature (degC)40degC 200degC

35E ndash 04

30E ndash 04

25E ndash 04

20E ndash 04

15E ndash 04

10E ndash 04

50E ndash 05

00E + 00

Spec

ific w

ear r

ate (

mm

3 Nm

)

Figure 6 Specic wear rate of the pins at 40degC and 200degC

4 Advances in Materials Science and Engineering

k V

FN middot sΔm1113870ρFN middot s

Δm

ρ middot FN middot s (1)

whereV (mm3) is the volume lossΔm (kg) is the weight lossρ (kgmm3) is the density FN (N) is the applied normal loadand s (m) is the sliding distance Figures 5 and 6 show thespecific wear rates for the disks and pins respectively

Studying the results obtained from the specific wearcalculation it is concluded that the change in test tem-perature from 40degC to 200degC influences the tribologicalbehaviour of the three analysed tool steels against 22MnB5at least for steel 2 and steel 3 As mentioned by other authors[3] as the temperature increases the COF decreases whilethe wear of the tool increases In order to verify if the wearincrease is related to the thermal softening (tempering) ofthe tool steels the hardness of the disks tested at 200degC waschecked on the wear tracks and no variations from theinitial values were found (us the increase of the specificwear rate in the present work is not related with any soft-ening since the specimens tested at 200degC maintained theirhardness after the test

It was seen that steel 1 had similar wear rates at both 40degCand 200degC (is behaviour has been also reported by Denget al [6] who analysed the wear of hot work tool steel against22MnB5 steel without coating and observed that the wearrate at 200degC was lower than that at 40degC Similar results havebeen presented elsewhere [3] on studies made with 22MnB5steel as the test temperature increased the wear of the diskof tool steel decreased (is behaviour is understood to berelated to the formation of a compact oxide layer whichprotects the surface from wear

It is worth remarking that although the wear response ofsteel 1 was the poorest at 40degC the three studied steelsbehaved nearly the same at 200degC (is effect of equalizationat high temperature has also been reported for tool steels [2]Regarding the wear rate of the pins all specimens tested at40degC showed a much higher rate than the tool steels

By analysing the surface of the disks with electron mi-croscopy (FEG-SEMEDS) the disks of steel 2 and steel 3show debris from an oxide layer on the surface which isrelated with the low wear rate (e layer protects the disksurface against wear (Figures 7ndash10) which avoids metal-metal contact (e noncompacted wear debris particlescaused an abrasive wear on the disk surfaces

33 Contact Path After each test the profile disk of thecontact paths was characterised by measuring the maximumprofile height and depth as shown in Figures 11ndash13 wherethe vertical axis shows the height (z) and the horizontal axisshows the width (x)

By analysing the contact path the shallowest groovedepths were measured for steel 2 and steel 3 at 40degC withvalues of 7 and 10 microm respectively (Figures 11 and 12)Additionally from contact profilometry measurements it wasverified that the profile height increases due to the presence ofan oxide layer in some zones on the surface

In contrast steel 1 showed a larger amount of wearIn this case the disk surface presented numerous grooves

and zones covered by a compact oxide layer were hardlyidentified (Figure 14) (e maximum groove depth reached25 microm (Figure 13)

It is concluded that at 40degC test temperature the harderthe tool steel is the higher the abrasive wear resistancewhich explains the lower values of wear rate obtained forsteel 2 and steel 3 In this case the wear resistance is gov-erned by the hardness of the martensitic matrix Hence thelower hardness of the steel 1 disk is not enough for it towithstand the large abrasive action occurring between thedisk and the pin which leads to a high groove formation andconsequently high abrasive wear

At a 200degC test temperature the surface characteristicsand the wear rates of three tool steels were very similarDespite the large hardness of tool steels a lower wear ratevalue is related to the presence of an oxide layer that partiallycovers the disk surface thus protecting it against wear It isassumed that the formation of the oxide layer is similar forthe three tool steels (e surfaces were characterized byelectron microscopy (Figures 15 and 16) and via contactprofile measurements (Figures 17ndash19) It was observed thatthe wear of the three steel disks was abrasive with maximumdepths of the grooves between 29 and 38 microm

In relation with the wear rate of the disks at the 200degC testtemperature the results are similar with those presented byother authors [3 6] and the differences between results wereprobably caused by the different roughness of the specimensIn these works the authors observed an agglomeration andcompacting of oxidized wear debris in the tool steel surfacethat formed a protective layer against wear (is layer wasable to stand the load and avoid the metal-metal contactduring the test

In this work some zones with a protective oxide layerwere also observed In the case of steels 2 and 3 the wear rateincreased by one order of magnitude from the test per-formed at 40degC to the test at 200degC (Figures 5 and 6) In thecase of steel 1 an increase in the test temperature presenteda slight decrease in the wear rate

Regarding the analysis of the three steel surfaces testedat 200degC an accumulation of wear debris due to theabrasive action suffered by the disks (Figures 15 and 16)

Sliding direction

Oxide layer

100 μm

Figure 7 Scanning electron microscope micrograph of the steel 2disk surface tested at 40degC

Advances in Materials Science and Engineering 5

Full scale 953 cts cursor ndash0017 (761 cts)0

CW

K

Fe W

Mo

Mo VCr

Cr

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

O

Figure 8 EDS spectrum of the oxides in Figure 7

Sliding direction

Oxide layer

100 μm

Figure 9 Scanning electron microscope micrograph of the steel 3 disk surface tested at 40degC

Full scale 1054 cts cursor ndash0017 (790 cts)0

C

Fe

MoMo V

Cr

Cr

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

O

Figure 10 EDS spectrum of the oxides in Figure 9

6 Advances in Materials Science and Engineering

6420

0 20004000

6000 8000 01000

20003000

4000

ndash2ndash4ndash6

ndash6 ndash4 ndash2 0 2 4

ndash8

(a)

000 100 200 300 400 500 600550450350250150050ndash1000

ndash800

ndash600

ndash400

ndash200

000

200

400

600

800

1000

z (microm

)

x (mm)

+rms

ndashrms

(b)

Figure 11 13ree-dimensional image of the disk track of steel 2 tested at 40degC (a) 13e maximum prole depth (7 microm) (b)

5

0

0

0 500 1000 1500 2000 2500 3000 350010000

5000

ndash5

ndash10

ndash8 ndash6 ndash4 ndash2 0 2 4

ndash15

(a)

000ndash2000ndash1800ndash1600ndash1400ndash1200ndash1000ndash800ndash600ndash400ndash200

000200400600800

1000

050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 12 13ree-dimensional image of the disk track of steel 3 tested at 40degC (a) 13e maximum prole depth (10 microm) (b)

10

0

ndash10

ndash20

ndash30

ndash30 ndash25 ndash20 ndash15 ndash10 0 5 10ndash5

ndash400 1000 2000 3000 4000 5000 6000 7000 0

10002000

30004000

(a)

000ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 13 13ree-dimensional image of the disk track of steel 1 tested at 40degC (a) 13e maximum prole depth (25 microm) (b)

Advances in Materials Science and Engineering 7

was observed Despite the wear debris accumulationsome zones of the surface were covered by an oxide layer(Figure 16) It seems that the release of the oxide layerparticles causes a three-body wear that causes largeabrasive wear in the disk surface and generates deep depthgrooves

When the test temperature increased from 40degC to200degC a high amount of oxide was observed on the disksurface according to works in the literature [3 6] the oxidelayer should breaks into pieces easily below 300degC (epresence and release of oxides imply an increase in wear rateas the temperature increased A larger amount of hard oxides

Sliding direction

Oxide layer

100 μm

Figure 14 Scanning electron microscope micrograph of the steel 1 disk surface tested at 40degC

Compacted particle

Sliding direction

100 μm

Figure 15 Scanning electron microscope micrograph of the steel 1 disk surface tested at 200degC

Sliding direction

Oxide layer

100 μm

Compacted particle

Figure 16 Scanning electron microscope micrograph of the steel 2 disk surface tested at 200degC

8 Advances in Materials Science and Engineering

directly acurrenects the wear resistance of the tool steel whenworking against uncoated 22MnB5

From the obtained results it is concluded that at a test-temperature of 200degC the release of oxide particles negativelyacurrenects the wear resistance of the tool steels Also the largehardness of tool steel 2 (57HRC) was not enough for it towithstand the abrasive action of the oxide particles Tool steel1 presented the best wear behaviour even though it had thesmallest relative hardness Analysing the chemical compo-sition of the steels steel 1 presented the largest vanadiumcontent Using a scanning electron microscope (SEM modelPhillips) our EDS analysis identied the nature of the car-bides in each steel sample13e carbides present in steel 2 wererich in molybdenum and the ones in steel 3 were rich inchromium Hence the better wear behaviour of steel 1 at200degC is related with the nature of the carbides which wererich in vanadium (Figure 20) In the test at 200degC it seems that

the wear behaviour of each steel was governed by the carbidehardness present in the steel sample rather than the mar-tensitic matrix hardness (Figure 21)

When analysing the three carbides the vanadium car-bides due to their hardness and chemical nature were themost ecient at improving the wear resistance In contrastthe chromium carbides were the less ecient (Table 5)

4 Conclusions

13e results obtained from pin-on-disk tests using a SRVtribometer and temperatures of 40degC and 200degC werepresented as a method for determining the wear behaviourand the durability of the three selected hot work tool steels

13e slight decrease observed in the COF as the tem-peratures increased to 200degC was related to oxide layerformation Despite the drop in the friction coecient the

30

20

10

0

0 500 1000 1500 2000 2500 3000 3500 100005000

0

ndash10

ndash20

ndash30

ndash40

3020100ndash10ndash20ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 17 13ree-dimensional image of the disk track of steel 1 tested at 200degC (a) 13e maximum prole depth (38 microm) (b)

10

0

0

0 500 1000 1500 2000 2500 3000 3500

2000

4000

6000

8000

ndash10

ndash20

ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 18 13ree-dimensional image of the disk track of steel 2 tested at 200degC (a) 13e maximum prole depth (29 microm) (b)

Advances in Materials Science and Engineering 9

Full scale 3663 cts cursor ndash0021 (316 cts)0

CMnO

Fe

SWMoMo

Mo

VCr

Mn

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

Carbide steel 1Carbide steel 2Carbide steel 3

Figure 20 Comparison of the carbidesrsquo nature of the tool steels studied

20 μm

(a)

20 μm

(b)

20 μm

(c)

Figure 21 Detailed micrograph of steel 1 (a) steel 2 (b) and steel 3 (c)

10

ndash10

ndash20

ndash25 ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

ndash40

0

0 500 1000 1500 2000 2500 3000 3500

02000

40006000

8000

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

ndashrms

Z (μ

m)

(b)

Figure 19 13ree-dimensional image of the disk track of steel 3 tested at 200degC (a) 13e maximum prole depth (32 microm) (b)

10 Advances in Materials Science and Engineering

wear rate of the disks at 200degC was higher than that at 40degCfor the steel 2 and steel 3 samples At this temperature steel 1and steel 2 showed similar behaviour while steel 3 per-formed worse

SEM inspections confirmed that oxide layer debriswhich is unstable at temperatures less than 300degC is releasedfrom the steel surface during the SRV test (ese releasedoxides are hard abrasive particles leading to severe three-body wear and the formation of depth grooves (is wearmechanism affected each tool steel with different levels ofseverity depending on the nature of the carbides in theirmicrostructure Steel 1 and steel 2 bearing vanadium andmolybdenum carbides whose hardness is larger than those ofthe chromium carbides in steel 3 had greater wear resistanceat 200degC

It must be remarked that even though steel 1 out-performed steel 3 in terms of wear resistance at 200degC itshows lower room temperature hardness (us the HRChardness which represents an average hardness of themartensitic matrix and the carbides of the tool steel cannotbe the only guidance when designing hot forming tool steels

Conflicts of Interest

(e authors declare that they have no conflicts of interest

Acknowledgments

(e authors gratefully acknowledge the funding provided bythe Department of Research and Universities of the BasqueGovernment under Grant no IT947-16 and the University ofthe Basque Country UPVEHU under Program no UFI 1129

References

[1] O N Cora K Namiki and M Koc ldquoWear performance as-sessment of alternative stamping die materials utilizing a noveltest systemrdquo Wear vol 267 no 5ndash8 pp 1123ndash1129 2009

[2] J Hardell and B Prakash ldquoHigh-temperature friction andwear behaviour of different tool steels during sliding againstAlndashSi-coated high-strength steelrdquo Tribology Internationalvol 41 no 7 pp 663ndash671 2008

[3] J Hardell S Hernandez S Mozgovoy L PelcastreC Courbon and B Prakash ldquoEffect of oxide layers and nearsurface transformations on friction and wear during tool steeland boron steel interaction at high temperaturesrdquo Wearvol 330ndash331 pp 223ndash229 2015

[4] C Boher S Le Roux L Penazzi and C Dessain ldquoExperi-mental investigation of the tribological behavior and wearmechanisms of tool steel grades in hot stamping of a high-strength boron steelrdquo Wear vol 294-295 pp 286ndash295 2012

[5] A Ghiotti F Sgarabotto and S Bruschi ldquoA novel approach towear testing in hot stamping of high strength boron steelsheetsrdquo Wear vol 302 no 1-2 pp 1319ndash1326 2013

[6] L Deng SMozgovoy J Hardell B Prakash andMOldenburgldquoPress-hardening thermo- mechanical conditions in the contactbetween blank and toolrdquo in Proceedings of 4th InternationalConference on Hot Sheet Metal Forming of High-PerformanceSteel (CHS2) pp 293ndash300 Lulea Sweden June 2013

[7] A Ghiotti S Bruschi and F Borsetto ldquoTribological char-acteristics of high strength steel sheets under hot stampingconditionsrdquo Journal of Materials Processing Technologyvol 211 no 11 pp 1694ndash1700 2011

[8] G A Fontalvo and C Mitterer ldquo(e effect of oxide-formingalloying elements on the high temperature wear of a hot worksteelrdquo Wear vol 258 no 10 pp 1491ndash1499 2005

[9] L Pelcastre J Hardell and B Prakash ldquoGalling mechanismsduring interaction of tool steel and AlndashSi coated ultra-highstrength steel at elevated temperaturerdquo Tribology In-ternational vol 67 pp 263ndash271 2013

[10] K Dohda C Boher F Rezai-Aria and N MahayotsanunldquoTribology in metal forming at elevated temperaturesrdquoFriction vol 3 no 1 pp 1ndash27 2015

[11] G A Fontalvo R Humer C Mitterer K Sammt andI Schemmel ldquoMicrostructural aspects determining the ad-hesive wear of tool steelsrdquo Wear vol 260 no 9-10pp 1028ndash1034 2006

[12] I Hussainova E Hamed and I Jasiuk ldquoNanoindentationtesting and modeling of chromium-carbide-based compos-itesrdquo Mechanics of Composite Materials vol 46 no 6pp 667ndash678 2011

[13] Y Z Liu Y H Jiang J Feng and R Zhou ldquoElasticityelectronic properties and hardness of MoC investigated byfirst principles calculationsrdquo Physica B Condensed Mattervol 419 pp 45ndash50 2013

[14] L Wu T Yao Y Wang J Zhang F Xiao and B LiaoldquoUnderstanding the mechanical properties of vanadiumcarbides nano-indentation measurement and first-principlescalculationsrdquo Journal of Alloys and Compounds vol 548pp 60ndash64 2013

Table 5 Different carbides hardness

Nature of the carbide Hardness (GPa)Chromium carbides 102ndash20 [12]Molybdenum carbides 1339ndash2887 [13]Vanadium carbides 117ndash315 [14]

Advances in Materials Science and Engineering 11

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Hindawiwwwhindawicom Volume 2018

Na

nom

ate

ria

ls

Hindawiwwwhindawicom Volume 2018

Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

which permits to condition the test disks at the selectedtemperature 13e SRV tribometer was equipped witha computerized data acquisition and control system so thatthe applied load temperature stroke length and frequencyof the oscillatory movement were controlled and monitored

13e selection of the test parameters was based on typicalhot stamping pressure used in industrial applications13e parameters were a load of 31N a nominal pressure of10MPa a stroke length of 4mm temperatures of 40 and200degC a frequency of 25Hz and duration of 900 s 13e totallength of each test was 90m

23 Test Procedures 13e tests were performed at tempera-tures of 40degC and 200degC Before the tests started all disks andpins were ultrasonically cleaned rst in ether for 5min andthen for 5 more min in acetone After that all specimenswere cleaned with paper and placed in a dryer to eliminate allpossible moisture 13e specimens were held in the dryeruntil the tests started and before the beginning of each testthe specimens were weighted

13e tests started with the heating of the lower specimen(tool steel) to the desired temperature and held for 5min atthat set-point in order to ensure a homogenous temper-ature distribution along the disk 13e upper pin specimenwas kept separated from the disk during the heating se-quence After the disk reached the test temperature andthe 5min dwell time was over the pin was brought intocontact with the disk the load was applied and the test wasperformed

Once the test was nalized each specimen was cleanedagain ultrasonically for 5min in ether and 5 more min inacetone After the cleaning the wear of the disk and pinwas measured 13e measurements of the weight loss of thespecimens were made with a precision weighting scalemodel Mettler Toledo XP205 13e wear volume of the diskswas also measured using a Nikon Eclipse ME600 confocalmicroscope

13e wear scars of the disk and the microstructure wereexamined with an Ultra Plus Zeiss Field Emission Gun-Scanning Electron Microscope (FEG-SEM) and the natureof the carbides in the tool steels was analysed via an Energy-dispersive X-ray Spectroscopy (EDS) analysis

3 Results and Discussion

31 Coecient of Friction During each test the evolution ofthe coecient of friction (COF) with time was recorded asshown in Figures 3 and 4

13e average values of the COF obtained in the tests arepresented in Table 4

When analysing the evolution of the COF with timeduring the test it was observed that the three tool steelshave a similar behaviour at both test temperatures 40degCand 200degC 13ere is no relation between the hardness leveland the COF for the three tool steels and the COFdecreases by around 15 as the test temperature increased

100 200 300 400 500 600 700 800 900

COF

(μ)

Time (s)

Steel 1 40degCSteel 2 40degCSteel 3 40degC

16

14

12

1

0806

04

02

00

Figure 3 COF of the tests performed at 40degC

COF

(μ)

Steel 1 200degCSteel 2 200degCSteel 3 200degC

16

14

12

1

08

06

04

02

00 100 200 300 400 500 600 700 800 900

Time (s)

Figure 4 COF of the tests performed at 200degC

Table 4 Average COF

Material Test temperature (degC) Average COF

Steel 1 40 090plusmn 0005200 080plusmn 0005

Steel 2 40 100plusmn 0005200 090plusmn 0005

Steel 3 40 080plusmn 0005200 070plusmn 0005

Figure 2 Upper and lower specimens in the SRV machine

Advances in Materials Science and Engineering 3

to 200degC 13is tendency was previously observed by othersauthors [3]

32 Wear 13e evolution of the pin wear was measured interms of specimen weight loss For the disks the wearcharacterization was made by quantifying the weight lossand the volume lossincrease with a confocal microscopeFigures 5 and 6 show the specic wear rates of the threetested group of materials (disks and pins)

321 Weight Loss At a temperature of 40degC the pin anddisk weight losses for the tests with steel 2 and steel 3 werelower than the results obtained for steel 113e tests with steel3 stand out because they present the lowest wear in the diskand an intermediate wear on the pin 13is behaviour isrelated with the hardness level of the steel 3 (56HRC)Nevertheless the dicurrenerences in weight loss between the steel2 and steel 3 disks were not large

At a temperature of 200degC the pin wear was lower thanthat at a temperature of 40degC Regarding the disks steel 1 andsteel 2 present similar wear even though their hardness aredicurrenerent that is 51HRC and 57HRC respectively Steel 3showed the highest wear despite its high hardness (56HRC)Nevertheless it is important to emphasise that the wearbehaviour of these three steels at 200degC is similar despitetheir hardness dicurrenerences

A dicurrenerence in behaviour as a function of temperaturewas clearly observed for the three tool steel samples Higherdicurrenerences were observed at 40degC where steel 2 and steel 3presented lower wear in comparison with steel 1 As thetemperature increased to 200degC oxide formation may occurwhich decreases pin wear In contrast as the test temperatureincreased disk wear increased mainly for steel 2 and steel 3

322 Wear Rate In addition to the weight and volumeloss the wear rate of the pins and disks was calculated13e specic wear rate (k) is expressed by

Tool steel 1(51HRC)

Tool steel 2(57HRC)

Tool steel 3(56HRC)

Tool steel 1(51HRC)

Tool steel 2(57HRC)

Tool steel 3(56HRC)

Temperature (degC)40degC 200degC

10E ndash 04

90E ndash 05

80E ndash 05

70E ndash 05

60E ndash 05

50E ndash 05

40E ndash 05

30E ndash 05

20E ndash 05

10E ndash 05

00E + 00

Spec

ific w

ear r

ate (

mm

3 Nm

)

Figure 5 Specic wear rate of the disks at 40degC and 200degC

Tool steel 1(51HRC)

Tool steel 2(57HRC)

Tool steel 3(56HRC)

Tool steel 1(51HRC)

Tool steel 2(57HRC)

Tool steel 3(56HRC)

Temperature (degC)40degC 200degC

35E ndash 04

30E ndash 04

25E ndash 04

20E ndash 04

15E ndash 04

10E ndash 04

50E ndash 05

00E + 00

Spec

ific w

ear r

ate (

mm

3 Nm

)

Figure 6 Specic wear rate of the pins at 40degC and 200degC

4 Advances in Materials Science and Engineering

k V

FN middot sΔm1113870ρFN middot s

Δm

ρ middot FN middot s (1)

whereV (mm3) is the volume lossΔm (kg) is the weight lossρ (kgmm3) is the density FN (N) is the applied normal loadand s (m) is the sliding distance Figures 5 and 6 show thespecific wear rates for the disks and pins respectively

Studying the results obtained from the specific wearcalculation it is concluded that the change in test tem-perature from 40degC to 200degC influences the tribologicalbehaviour of the three analysed tool steels against 22MnB5at least for steel 2 and steel 3 As mentioned by other authors[3] as the temperature increases the COF decreases whilethe wear of the tool increases In order to verify if the wearincrease is related to the thermal softening (tempering) ofthe tool steels the hardness of the disks tested at 200degC waschecked on the wear tracks and no variations from theinitial values were found (us the increase of the specificwear rate in the present work is not related with any soft-ening since the specimens tested at 200degC maintained theirhardness after the test

It was seen that steel 1 had similar wear rates at both 40degCand 200degC (is behaviour has been also reported by Denget al [6] who analysed the wear of hot work tool steel against22MnB5 steel without coating and observed that the wearrate at 200degC was lower than that at 40degC Similar results havebeen presented elsewhere [3] on studies made with 22MnB5steel as the test temperature increased the wear of the diskof tool steel decreased (is behaviour is understood to berelated to the formation of a compact oxide layer whichprotects the surface from wear

It is worth remarking that although the wear response ofsteel 1 was the poorest at 40degC the three studied steelsbehaved nearly the same at 200degC (is effect of equalizationat high temperature has also been reported for tool steels [2]Regarding the wear rate of the pins all specimens tested at40degC showed a much higher rate than the tool steels

By analysing the surface of the disks with electron mi-croscopy (FEG-SEMEDS) the disks of steel 2 and steel 3show debris from an oxide layer on the surface which isrelated with the low wear rate (e layer protects the disksurface against wear (Figures 7ndash10) which avoids metal-metal contact (e noncompacted wear debris particlescaused an abrasive wear on the disk surfaces

33 Contact Path After each test the profile disk of thecontact paths was characterised by measuring the maximumprofile height and depth as shown in Figures 11ndash13 wherethe vertical axis shows the height (z) and the horizontal axisshows the width (x)

By analysing the contact path the shallowest groovedepths were measured for steel 2 and steel 3 at 40degC withvalues of 7 and 10 microm respectively (Figures 11 and 12)Additionally from contact profilometry measurements it wasverified that the profile height increases due to the presence ofan oxide layer in some zones on the surface

In contrast steel 1 showed a larger amount of wearIn this case the disk surface presented numerous grooves

and zones covered by a compact oxide layer were hardlyidentified (Figure 14) (e maximum groove depth reached25 microm (Figure 13)

It is concluded that at 40degC test temperature the harderthe tool steel is the higher the abrasive wear resistancewhich explains the lower values of wear rate obtained forsteel 2 and steel 3 In this case the wear resistance is gov-erned by the hardness of the martensitic matrix Hence thelower hardness of the steel 1 disk is not enough for it towithstand the large abrasive action occurring between thedisk and the pin which leads to a high groove formation andconsequently high abrasive wear

At a 200degC test temperature the surface characteristicsand the wear rates of three tool steels were very similarDespite the large hardness of tool steels a lower wear ratevalue is related to the presence of an oxide layer that partiallycovers the disk surface thus protecting it against wear It isassumed that the formation of the oxide layer is similar forthe three tool steels (e surfaces were characterized byelectron microscopy (Figures 15 and 16) and via contactprofile measurements (Figures 17ndash19) It was observed thatthe wear of the three steel disks was abrasive with maximumdepths of the grooves between 29 and 38 microm

In relation with the wear rate of the disks at the 200degC testtemperature the results are similar with those presented byother authors [3 6] and the differences between results wereprobably caused by the different roughness of the specimensIn these works the authors observed an agglomeration andcompacting of oxidized wear debris in the tool steel surfacethat formed a protective layer against wear (is layer wasable to stand the load and avoid the metal-metal contactduring the test

In this work some zones with a protective oxide layerwere also observed In the case of steels 2 and 3 the wear rateincreased by one order of magnitude from the test per-formed at 40degC to the test at 200degC (Figures 5 and 6) In thecase of steel 1 an increase in the test temperature presenteda slight decrease in the wear rate

Regarding the analysis of the three steel surfaces testedat 200degC an accumulation of wear debris due to theabrasive action suffered by the disks (Figures 15 and 16)

Sliding direction

Oxide layer

100 μm

Figure 7 Scanning electron microscope micrograph of the steel 2disk surface tested at 40degC

Advances in Materials Science and Engineering 5

Full scale 953 cts cursor ndash0017 (761 cts)0

CW

K

Fe W

Mo

Mo VCr

Cr

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

O

Figure 8 EDS spectrum of the oxides in Figure 7

Sliding direction

Oxide layer

100 μm

Figure 9 Scanning electron microscope micrograph of the steel 3 disk surface tested at 40degC

Full scale 1054 cts cursor ndash0017 (790 cts)0

C

Fe

MoMo V

Cr

Cr

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

O

Figure 10 EDS spectrum of the oxides in Figure 9

6 Advances in Materials Science and Engineering

6420

0 20004000

6000 8000 01000

20003000

4000

ndash2ndash4ndash6

ndash6 ndash4 ndash2 0 2 4

ndash8

(a)

000 100 200 300 400 500 600550450350250150050ndash1000

ndash800

ndash600

ndash400

ndash200

000

200

400

600

800

1000

z (microm

)

x (mm)

+rms

ndashrms

(b)

Figure 11 13ree-dimensional image of the disk track of steel 2 tested at 40degC (a) 13e maximum prole depth (7 microm) (b)

5

0

0

0 500 1000 1500 2000 2500 3000 350010000

5000

ndash5

ndash10

ndash8 ndash6 ndash4 ndash2 0 2 4

ndash15

(a)

000ndash2000ndash1800ndash1600ndash1400ndash1200ndash1000ndash800ndash600ndash400ndash200

000200400600800

1000

050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 12 13ree-dimensional image of the disk track of steel 3 tested at 40degC (a) 13e maximum prole depth (10 microm) (b)

10

0

ndash10

ndash20

ndash30

ndash30 ndash25 ndash20 ndash15 ndash10 0 5 10ndash5

ndash400 1000 2000 3000 4000 5000 6000 7000 0

10002000

30004000

(a)

000ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 13 13ree-dimensional image of the disk track of steel 1 tested at 40degC (a) 13e maximum prole depth (25 microm) (b)

Advances in Materials Science and Engineering 7

was observed Despite the wear debris accumulationsome zones of the surface were covered by an oxide layer(Figure 16) It seems that the release of the oxide layerparticles causes a three-body wear that causes largeabrasive wear in the disk surface and generates deep depthgrooves

When the test temperature increased from 40degC to200degC a high amount of oxide was observed on the disksurface according to works in the literature [3 6] the oxidelayer should breaks into pieces easily below 300degC (epresence and release of oxides imply an increase in wear rateas the temperature increased A larger amount of hard oxides

Sliding direction

Oxide layer

100 μm

Figure 14 Scanning electron microscope micrograph of the steel 1 disk surface tested at 40degC

Compacted particle

Sliding direction

100 μm

Figure 15 Scanning electron microscope micrograph of the steel 1 disk surface tested at 200degC

Sliding direction

Oxide layer

100 μm

Compacted particle

Figure 16 Scanning electron microscope micrograph of the steel 2 disk surface tested at 200degC

8 Advances in Materials Science and Engineering

directly acurrenects the wear resistance of the tool steel whenworking against uncoated 22MnB5

From the obtained results it is concluded that at a test-temperature of 200degC the release of oxide particles negativelyacurrenects the wear resistance of the tool steels Also the largehardness of tool steel 2 (57HRC) was not enough for it towithstand the abrasive action of the oxide particles Tool steel1 presented the best wear behaviour even though it had thesmallest relative hardness Analysing the chemical compo-sition of the steels steel 1 presented the largest vanadiumcontent Using a scanning electron microscope (SEM modelPhillips) our EDS analysis identied the nature of the car-bides in each steel sample13e carbides present in steel 2 wererich in molybdenum and the ones in steel 3 were rich inchromium Hence the better wear behaviour of steel 1 at200degC is related with the nature of the carbides which wererich in vanadium (Figure 20) In the test at 200degC it seems that

the wear behaviour of each steel was governed by the carbidehardness present in the steel sample rather than the mar-tensitic matrix hardness (Figure 21)

When analysing the three carbides the vanadium car-bides due to their hardness and chemical nature were themost ecient at improving the wear resistance In contrastthe chromium carbides were the less ecient (Table 5)

4 Conclusions

13e results obtained from pin-on-disk tests using a SRVtribometer and temperatures of 40degC and 200degC werepresented as a method for determining the wear behaviourand the durability of the three selected hot work tool steels

13e slight decrease observed in the COF as the tem-peratures increased to 200degC was related to oxide layerformation Despite the drop in the friction coecient the

30

20

10

0

0 500 1000 1500 2000 2500 3000 3500 100005000

0

ndash10

ndash20

ndash30

ndash40

3020100ndash10ndash20ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 17 13ree-dimensional image of the disk track of steel 1 tested at 200degC (a) 13e maximum prole depth (38 microm) (b)

10

0

0

0 500 1000 1500 2000 2500 3000 3500

2000

4000

6000

8000

ndash10

ndash20

ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 18 13ree-dimensional image of the disk track of steel 2 tested at 200degC (a) 13e maximum prole depth (29 microm) (b)

Advances in Materials Science and Engineering 9

Full scale 3663 cts cursor ndash0021 (316 cts)0

CMnO

Fe

SWMoMo

Mo

VCr

Mn

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

Carbide steel 1Carbide steel 2Carbide steel 3

Figure 20 Comparison of the carbidesrsquo nature of the tool steels studied

20 μm

(a)

20 μm

(b)

20 μm

(c)

Figure 21 Detailed micrograph of steel 1 (a) steel 2 (b) and steel 3 (c)

10

ndash10

ndash20

ndash25 ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

ndash40

0

0 500 1000 1500 2000 2500 3000 3500

02000

40006000

8000

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

ndashrms

Z (μ

m)

(b)

Figure 19 13ree-dimensional image of the disk track of steel 3 tested at 200degC (a) 13e maximum prole depth (32 microm) (b)

10 Advances in Materials Science and Engineering

wear rate of the disks at 200degC was higher than that at 40degCfor the steel 2 and steel 3 samples At this temperature steel 1and steel 2 showed similar behaviour while steel 3 per-formed worse

SEM inspections confirmed that oxide layer debriswhich is unstable at temperatures less than 300degC is releasedfrom the steel surface during the SRV test (ese releasedoxides are hard abrasive particles leading to severe three-body wear and the formation of depth grooves (is wearmechanism affected each tool steel with different levels ofseverity depending on the nature of the carbides in theirmicrostructure Steel 1 and steel 2 bearing vanadium andmolybdenum carbides whose hardness is larger than those ofthe chromium carbides in steel 3 had greater wear resistanceat 200degC

It must be remarked that even though steel 1 out-performed steel 3 in terms of wear resistance at 200degC itshows lower room temperature hardness (us the HRChardness which represents an average hardness of themartensitic matrix and the carbides of the tool steel cannotbe the only guidance when designing hot forming tool steels

Conflicts of Interest

(e authors declare that they have no conflicts of interest

Acknowledgments

(e authors gratefully acknowledge the funding provided bythe Department of Research and Universities of the BasqueGovernment under Grant no IT947-16 and the University ofthe Basque Country UPVEHU under Program no UFI 1129

References

[1] O N Cora K Namiki and M Koc ldquoWear performance as-sessment of alternative stamping die materials utilizing a noveltest systemrdquo Wear vol 267 no 5ndash8 pp 1123ndash1129 2009

[2] J Hardell and B Prakash ldquoHigh-temperature friction andwear behaviour of different tool steels during sliding againstAlndashSi-coated high-strength steelrdquo Tribology Internationalvol 41 no 7 pp 663ndash671 2008

[3] J Hardell S Hernandez S Mozgovoy L PelcastreC Courbon and B Prakash ldquoEffect of oxide layers and nearsurface transformations on friction and wear during tool steeland boron steel interaction at high temperaturesrdquo Wearvol 330ndash331 pp 223ndash229 2015

[4] C Boher S Le Roux L Penazzi and C Dessain ldquoExperi-mental investigation of the tribological behavior and wearmechanisms of tool steel grades in hot stamping of a high-strength boron steelrdquo Wear vol 294-295 pp 286ndash295 2012

[5] A Ghiotti F Sgarabotto and S Bruschi ldquoA novel approach towear testing in hot stamping of high strength boron steelsheetsrdquo Wear vol 302 no 1-2 pp 1319ndash1326 2013

[6] L Deng SMozgovoy J Hardell B Prakash andMOldenburgldquoPress-hardening thermo- mechanical conditions in the contactbetween blank and toolrdquo in Proceedings of 4th InternationalConference on Hot Sheet Metal Forming of High-PerformanceSteel (CHS2) pp 293ndash300 Lulea Sweden June 2013

[7] A Ghiotti S Bruschi and F Borsetto ldquoTribological char-acteristics of high strength steel sheets under hot stampingconditionsrdquo Journal of Materials Processing Technologyvol 211 no 11 pp 1694ndash1700 2011

[8] G A Fontalvo and C Mitterer ldquo(e effect of oxide-formingalloying elements on the high temperature wear of a hot worksteelrdquo Wear vol 258 no 10 pp 1491ndash1499 2005

[9] L Pelcastre J Hardell and B Prakash ldquoGalling mechanismsduring interaction of tool steel and AlndashSi coated ultra-highstrength steel at elevated temperaturerdquo Tribology In-ternational vol 67 pp 263ndash271 2013

[10] K Dohda C Boher F Rezai-Aria and N MahayotsanunldquoTribology in metal forming at elevated temperaturesrdquoFriction vol 3 no 1 pp 1ndash27 2015

[11] G A Fontalvo R Humer C Mitterer K Sammt andI Schemmel ldquoMicrostructural aspects determining the ad-hesive wear of tool steelsrdquo Wear vol 260 no 9-10pp 1028ndash1034 2006

[12] I Hussainova E Hamed and I Jasiuk ldquoNanoindentationtesting and modeling of chromium-carbide-based compos-itesrdquo Mechanics of Composite Materials vol 46 no 6pp 667ndash678 2011

[13] Y Z Liu Y H Jiang J Feng and R Zhou ldquoElasticityelectronic properties and hardness of MoC investigated byfirst principles calculationsrdquo Physica B Condensed Mattervol 419 pp 45ndash50 2013

[14] L Wu T Yao Y Wang J Zhang F Xiao and B LiaoldquoUnderstanding the mechanical properties of vanadiumcarbides nano-indentation measurement and first-principlescalculationsrdquo Journal of Alloys and Compounds vol 548pp 60ndash64 2013

Table 5 Different carbides hardness

Nature of the carbide Hardness (GPa)Chromium carbides 102ndash20 [12]Molybdenum carbides 1339ndash2887 [13]Vanadium carbides 117ndash315 [14]

Advances in Materials Science and Engineering 11

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Hindawiwwwhindawicom Volume 2018

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BioMed Research InternationalMaterials

Journal of

Hindawiwwwhindawicom Volume 2018

Na

nom

ate

ria

ls

Hindawiwwwhindawicom Volume 2018

Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

to 200degC 13is tendency was previously observed by othersauthors [3]

32 Wear 13e evolution of the pin wear was measured interms of specimen weight loss For the disks the wearcharacterization was made by quantifying the weight lossand the volume lossincrease with a confocal microscopeFigures 5 and 6 show the specic wear rates of the threetested group of materials (disks and pins)

321 Weight Loss At a temperature of 40degC the pin anddisk weight losses for the tests with steel 2 and steel 3 werelower than the results obtained for steel 113e tests with steel3 stand out because they present the lowest wear in the diskand an intermediate wear on the pin 13is behaviour isrelated with the hardness level of the steel 3 (56HRC)Nevertheless the dicurrenerences in weight loss between the steel2 and steel 3 disks were not large

At a temperature of 200degC the pin wear was lower thanthat at a temperature of 40degC Regarding the disks steel 1 andsteel 2 present similar wear even though their hardness aredicurrenerent that is 51HRC and 57HRC respectively Steel 3showed the highest wear despite its high hardness (56HRC)Nevertheless it is important to emphasise that the wearbehaviour of these three steels at 200degC is similar despitetheir hardness dicurrenerences

A dicurrenerence in behaviour as a function of temperaturewas clearly observed for the three tool steel samples Higherdicurrenerences were observed at 40degC where steel 2 and steel 3presented lower wear in comparison with steel 1 As thetemperature increased to 200degC oxide formation may occurwhich decreases pin wear In contrast as the test temperatureincreased disk wear increased mainly for steel 2 and steel 3

322 Wear Rate In addition to the weight and volumeloss the wear rate of the pins and disks was calculated13e specic wear rate (k) is expressed by

Tool steel 1(51HRC)

Tool steel 2(57HRC)

Tool steel 3(56HRC)

Tool steel 1(51HRC)

Tool steel 2(57HRC)

Tool steel 3(56HRC)

Temperature (degC)40degC 200degC

10E ndash 04

90E ndash 05

80E ndash 05

70E ndash 05

60E ndash 05

50E ndash 05

40E ndash 05

30E ndash 05

20E ndash 05

10E ndash 05

00E + 00

Spec

ific w

ear r

ate (

mm

3 Nm

)

Figure 5 Specic wear rate of the disks at 40degC and 200degC

Tool steel 1(51HRC)

Tool steel 2(57HRC)

Tool steel 3(56HRC)

Tool steel 1(51HRC)

Tool steel 2(57HRC)

Tool steel 3(56HRC)

Temperature (degC)40degC 200degC

35E ndash 04

30E ndash 04

25E ndash 04

20E ndash 04

15E ndash 04

10E ndash 04

50E ndash 05

00E + 00

Spec

ific w

ear r

ate (

mm

3 Nm

)

Figure 6 Specic wear rate of the pins at 40degC and 200degC

4 Advances in Materials Science and Engineering

k V

FN middot sΔm1113870ρFN middot s

Δm

ρ middot FN middot s (1)

whereV (mm3) is the volume lossΔm (kg) is the weight lossρ (kgmm3) is the density FN (N) is the applied normal loadand s (m) is the sliding distance Figures 5 and 6 show thespecific wear rates for the disks and pins respectively

Studying the results obtained from the specific wearcalculation it is concluded that the change in test tem-perature from 40degC to 200degC influences the tribologicalbehaviour of the three analysed tool steels against 22MnB5at least for steel 2 and steel 3 As mentioned by other authors[3] as the temperature increases the COF decreases whilethe wear of the tool increases In order to verify if the wearincrease is related to the thermal softening (tempering) ofthe tool steels the hardness of the disks tested at 200degC waschecked on the wear tracks and no variations from theinitial values were found (us the increase of the specificwear rate in the present work is not related with any soft-ening since the specimens tested at 200degC maintained theirhardness after the test

It was seen that steel 1 had similar wear rates at both 40degCand 200degC (is behaviour has been also reported by Denget al [6] who analysed the wear of hot work tool steel against22MnB5 steel without coating and observed that the wearrate at 200degC was lower than that at 40degC Similar results havebeen presented elsewhere [3] on studies made with 22MnB5steel as the test temperature increased the wear of the diskof tool steel decreased (is behaviour is understood to berelated to the formation of a compact oxide layer whichprotects the surface from wear

It is worth remarking that although the wear response ofsteel 1 was the poorest at 40degC the three studied steelsbehaved nearly the same at 200degC (is effect of equalizationat high temperature has also been reported for tool steels [2]Regarding the wear rate of the pins all specimens tested at40degC showed a much higher rate than the tool steels

By analysing the surface of the disks with electron mi-croscopy (FEG-SEMEDS) the disks of steel 2 and steel 3show debris from an oxide layer on the surface which isrelated with the low wear rate (e layer protects the disksurface against wear (Figures 7ndash10) which avoids metal-metal contact (e noncompacted wear debris particlescaused an abrasive wear on the disk surfaces

33 Contact Path After each test the profile disk of thecontact paths was characterised by measuring the maximumprofile height and depth as shown in Figures 11ndash13 wherethe vertical axis shows the height (z) and the horizontal axisshows the width (x)

By analysing the contact path the shallowest groovedepths were measured for steel 2 and steel 3 at 40degC withvalues of 7 and 10 microm respectively (Figures 11 and 12)Additionally from contact profilometry measurements it wasverified that the profile height increases due to the presence ofan oxide layer in some zones on the surface

In contrast steel 1 showed a larger amount of wearIn this case the disk surface presented numerous grooves

and zones covered by a compact oxide layer were hardlyidentified (Figure 14) (e maximum groove depth reached25 microm (Figure 13)

It is concluded that at 40degC test temperature the harderthe tool steel is the higher the abrasive wear resistancewhich explains the lower values of wear rate obtained forsteel 2 and steel 3 In this case the wear resistance is gov-erned by the hardness of the martensitic matrix Hence thelower hardness of the steel 1 disk is not enough for it towithstand the large abrasive action occurring between thedisk and the pin which leads to a high groove formation andconsequently high abrasive wear

At a 200degC test temperature the surface characteristicsand the wear rates of three tool steels were very similarDespite the large hardness of tool steels a lower wear ratevalue is related to the presence of an oxide layer that partiallycovers the disk surface thus protecting it against wear It isassumed that the formation of the oxide layer is similar forthe three tool steels (e surfaces were characterized byelectron microscopy (Figures 15 and 16) and via contactprofile measurements (Figures 17ndash19) It was observed thatthe wear of the three steel disks was abrasive with maximumdepths of the grooves between 29 and 38 microm

In relation with the wear rate of the disks at the 200degC testtemperature the results are similar with those presented byother authors [3 6] and the differences between results wereprobably caused by the different roughness of the specimensIn these works the authors observed an agglomeration andcompacting of oxidized wear debris in the tool steel surfacethat formed a protective layer against wear (is layer wasable to stand the load and avoid the metal-metal contactduring the test

In this work some zones with a protective oxide layerwere also observed In the case of steels 2 and 3 the wear rateincreased by one order of magnitude from the test per-formed at 40degC to the test at 200degC (Figures 5 and 6) In thecase of steel 1 an increase in the test temperature presenteda slight decrease in the wear rate

Regarding the analysis of the three steel surfaces testedat 200degC an accumulation of wear debris due to theabrasive action suffered by the disks (Figures 15 and 16)

Sliding direction

Oxide layer

100 μm

Figure 7 Scanning electron microscope micrograph of the steel 2disk surface tested at 40degC

Advances in Materials Science and Engineering 5

Full scale 953 cts cursor ndash0017 (761 cts)0

CW

K

Fe W

Mo

Mo VCr

Cr

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

O

Figure 8 EDS spectrum of the oxides in Figure 7

Sliding direction

Oxide layer

100 μm

Figure 9 Scanning electron microscope micrograph of the steel 3 disk surface tested at 40degC

Full scale 1054 cts cursor ndash0017 (790 cts)0

C

Fe

MoMo V

Cr

Cr

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

O

Figure 10 EDS spectrum of the oxides in Figure 9

6 Advances in Materials Science and Engineering

6420

0 20004000

6000 8000 01000

20003000

4000

ndash2ndash4ndash6

ndash6 ndash4 ndash2 0 2 4

ndash8

(a)

000 100 200 300 400 500 600550450350250150050ndash1000

ndash800

ndash600

ndash400

ndash200

000

200

400

600

800

1000

z (microm

)

x (mm)

+rms

ndashrms

(b)

Figure 11 13ree-dimensional image of the disk track of steel 2 tested at 40degC (a) 13e maximum prole depth (7 microm) (b)

5

0

0

0 500 1000 1500 2000 2500 3000 350010000

5000

ndash5

ndash10

ndash8 ndash6 ndash4 ndash2 0 2 4

ndash15

(a)

000ndash2000ndash1800ndash1600ndash1400ndash1200ndash1000ndash800ndash600ndash400ndash200

000200400600800

1000

050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 12 13ree-dimensional image of the disk track of steel 3 tested at 40degC (a) 13e maximum prole depth (10 microm) (b)

10

0

ndash10

ndash20

ndash30

ndash30 ndash25 ndash20 ndash15 ndash10 0 5 10ndash5

ndash400 1000 2000 3000 4000 5000 6000 7000 0

10002000

30004000

(a)

000ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 13 13ree-dimensional image of the disk track of steel 1 tested at 40degC (a) 13e maximum prole depth (25 microm) (b)

Advances in Materials Science and Engineering 7

was observed Despite the wear debris accumulationsome zones of the surface were covered by an oxide layer(Figure 16) It seems that the release of the oxide layerparticles causes a three-body wear that causes largeabrasive wear in the disk surface and generates deep depthgrooves

When the test temperature increased from 40degC to200degC a high amount of oxide was observed on the disksurface according to works in the literature [3 6] the oxidelayer should breaks into pieces easily below 300degC (epresence and release of oxides imply an increase in wear rateas the temperature increased A larger amount of hard oxides

Sliding direction

Oxide layer

100 μm

Figure 14 Scanning electron microscope micrograph of the steel 1 disk surface tested at 40degC

Compacted particle

Sliding direction

100 μm

Figure 15 Scanning electron microscope micrograph of the steel 1 disk surface tested at 200degC

Sliding direction

Oxide layer

100 μm

Compacted particle

Figure 16 Scanning electron microscope micrograph of the steel 2 disk surface tested at 200degC

8 Advances in Materials Science and Engineering

directly acurrenects the wear resistance of the tool steel whenworking against uncoated 22MnB5

From the obtained results it is concluded that at a test-temperature of 200degC the release of oxide particles negativelyacurrenects the wear resistance of the tool steels Also the largehardness of tool steel 2 (57HRC) was not enough for it towithstand the abrasive action of the oxide particles Tool steel1 presented the best wear behaviour even though it had thesmallest relative hardness Analysing the chemical compo-sition of the steels steel 1 presented the largest vanadiumcontent Using a scanning electron microscope (SEM modelPhillips) our EDS analysis identied the nature of the car-bides in each steel sample13e carbides present in steel 2 wererich in molybdenum and the ones in steel 3 were rich inchromium Hence the better wear behaviour of steel 1 at200degC is related with the nature of the carbides which wererich in vanadium (Figure 20) In the test at 200degC it seems that

the wear behaviour of each steel was governed by the carbidehardness present in the steel sample rather than the mar-tensitic matrix hardness (Figure 21)

When analysing the three carbides the vanadium car-bides due to their hardness and chemical nature were themost ecient at improving the wear resistance In contrastthe chromium carbides were the less ecient (Table 5)

4 Conclusions

13e results obtained from pin-on-disk tests using a SRVtribometer and temperatures of 40degC and 200degC werepresented as a method for determining the wear behaviourand the durability of the three selected hot work tool steels

13e slight decrease observed in the COF as the tem-peratures increased to 200degC was related to oxide layerformation Despite the drop in the friction coecient the

30

20

10

0

0 500 1000 1500 2000 2500 3000 3500 100005000

0

ndash10

ndash20

ndash30

ndash40

3020100ndash10ndash20ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 17 13ree-dimensional image of the disk track of steel 1 tested at 200degC (a) 13e maximum prole depth (38 microm) (b)

10

0

0

0 500 1000 1500 2000 2500 3000 3500

2000

4000

6000

8000

ndash10

ndash20

ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 18 13ree-dimensional image of the disk track of steel 2 tested at 200degC (a) 13e maximum prole depth (29 microm) (b)

Advances in Materials Science and Engineering 9

Full scale 3663 cts cursor ndash0021 (316 cts)0

CMnO

Fe

SWMoMo

Mo

VCr

Mn

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

Carbide steel 1Carbide steel 2Carbide steel 3

Figure 20 Comparison of the carbidesrsquo nature of the tool steels studied

20 μm

(a)

20 μm

(b)

20 μm

(c)

Figure 21 Detailed micrograph of steel 1 (a) steel 2 (b) and steel 3 (c)

10

ndash10

ndash20

ndash25 ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

ndash40

0

0 500 1000 1500 2000 2500 3000 3500

02000

40006000

8000

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

ndashrms

Z (μ

m)

(b)

Figure 19 13ree-dimensional image of the disk track of steel 3 tested at 200degC (a) 13e maximum prole depth (32 microm) (b)

10 Advances in Materials Science and Engineering

wear rate of the disks at 200degC was higher than that at 40degCfor the steel 2 and steel 3 samples At this temperature steel 1and steel 2 showed similar behaviour while steel 3 per-formed worse

SEM inspections confirmed that oxide layer debriswhich is unstable at temperatures less than 300degC is releasedfrom the steel surface during the SRV test (ese releasedoxides are hard abrasive particles leading to severe three-body wear and the formation of depth grooves (is wearmechanism affected each tool steel with different levels ofseverity depending on the nature of the carbides in theirmicrostructure Steel 1 and steel 2 bearing vanadium andmolybdenum carbides whose hardness is larger than those ofthe chromium carbides in steel 3 had greater wear resistanceat 200degC

It must be remarked that even though steel 1 out-performed steel 3 in terms of wear resistance at 200degC itshows lower room temperature hardness (us the HRChardness which represents an average hardness of themartensitic matrix and the carbides of the tool steel cannotbe the only guidance when designing hot forming tool steels

Conflicts of Interest

(e authors declare that they have no conflicts of interest

Acknowledgments

(e authors gratefully acknowledge the funding provided bythe Department of Research and Universities of the BasqueGovernment under Grant no IT947-16 and the University ofthe Basque Country UPVEHU under Program no UFI 1129

References

[1] O N Cora K Namiki and M Koc ldquoWear performance as-sessment of alternative stamping die materials utilizing a noveltest systemrdquo Wear vol 267 no 5ndash8 pp 1123ndash1129 2009

[2] J Hardell and B Prakash ldquoHigh-temperature friction andwear behaviour of different tool steels during sliding againstAlndashSi-coated high-strength steelrdquo Tribology Internationalvol 41 no 7 pp 663ndash671 2008

[3] J Hardell S Hernandez S Mozgovoy L PelcastreC Courbon and B Prakash ldquoEffect of oxide layers and nearsurface transformations on friction and wear during tool steeland boron steel interaction at high temperaturesrdquo Wearvol 330ndash331 pp 223ndash229 2015

[4] C Boher S Le Roux L Penazzi and C Dessain ldquoExperi-mental investigation of the tribological behavior and wearmechanisms of tool steel grades in hot stamping of a high-strength boron steelrdquo Wear vol 294-295 pp 286ndash295 2012

[5] A Ghiotti F Sgarabotto and S Bruschi ldquoA novel approach towear testing in hot stamping of high strength boron steelsheetsrdquo Wear vol 302 no 1-2 pp 1319ndash1326 2013

[6] L Deng SMozgovoy J Hardell B Prakash andMOldenburgldquoPress-hardening thermo- mechanical conditions in the contactbetween blank and toolrdquo in Proceedings of 4th InternationalConference on Hot Sheet Metal Forming of High-PerformanceSteel (CHS2) pp 293ndash300 Lulea Sweden June 2013

[7] A Ghiotti S Bruschi and F Borsetto ldquoTribological char-acteristics of high strength steel sheets under hot stampingconditionsrdquo Journal of Materials Processing Technologyvol 211 no 11 pp 1694ndash1700 2011

[8] G A Fontalvo and C Mitterer ldquo(e effect of oxide-formingalloying elements on the high temperature wear of a hot worksteelrdquo Wear vol 258 no 10 pp 1491ndash1499 2005

[9] L Pelcastre J Hardell and B Prakash ldquoGalling mechanismsduring interaction of tool steel and AlndashSi coated ultra-highstrength steel at elevated temperaturerdquo Tribology In-ternational vol 67 pp 263ndash271 2013

[10] K Dohda C Boher F Rezai-Aria and N MahayotsanunldquoTribology in metal forming at elevated temperaturesrdquoFriction vol 3 no 1 pp 1ndash27 2015

[11] G A Fontalvo R Humer C Mitterer K Sammt andI Schemmel ldquoMicrostructural aspects determining the ad-hesive wear of tool steelsrdquo Wear vol 260 no 9-10pp 1028ndash1034 2006

[12] I Hussainova E Hamed and I Jasiuk ldquoNanoindentationtesting and modeling of chromium-carbide-based compos-itesrdquo Mechanics of Composite Materials vol 46 no 6pp 667ndash678 2011

[13] Y Z Liu Y H Jiang J Feng and R Zhou ldquoElasticityelectronic properties and hardness of MoC investigated byfirst principles calculationsrdquo Physica B Condensed Mattervol 419 pp 45ndash50 2013

[14] L Wu T Yao Y Wang J Zhang F Xiao and B LiaoldquoUnderstanding the mechanical properties of vanadiumcarbides nano-indentation measurement and first-principlescalculationsrdquo Journal of Alloys and Compounds vol 548pp 60ndash64 2013

Table 5 Different carbides hardness

Nature of the carbide Hardness (GPa)Chromium carbides 102ndash20 [12]Molybdenum carbides 1339ndash2887 [13]Vanadium carbides 117ndash315 [14]

Advances in Materials Science and Engineering 11

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Hindawiwwwhindawicom Volume 2018

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Materials Science and EngineeringHindawiwwwhindawicom Volume 2018

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ria

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Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

k V

FN middot sΔm1113870ρFN middot s

Δm

ρ middot FN middot s (1)

whereV (mm3) is the volume lossΔm (kg) is the weight lossρ (kgmm3) is the density FN (N) is the applied normal loadand s (m) is the sliding distance Figures 5 and 6 show thespecific wear rates for the disks and pins respectively

Studying the results obtained from the specific wearcalculation it is concluded that the change in test tem-perature from 40degC to 200degC influences the tribologicalbehaviour of the three analysed tool steels against 22MnB5at least for steel 2 and steel 3 As mentioned by other authors[3] as the temperature increases the COF decreases whilethe wear of the tool increases In order to verify if the wearincrease is related to the thermal softening (tempering) ofthe tool steels the hardness of the disks tested at 200degC waschecked on the wear tracks and no variations from theinitial values were found (us the increase of the specificwear rate in the present work is not related with any soft-ening since the specimens tested at 200degC maintained theirhardness after the test

It was seen that steel 1 had similar wear rates at both 40degCand 200degC (is behaviour has been also reported by Denget al [6] who analysed the wear of hot work tool steel against22MnB5 steel without coating and observed that the wearrate at 200degC was lower than that at 40degC Similar results havebeen presented elsewhere [3] on studies made with 22MnB5steel as the test temperature increased the wear of the diskof tool steel decreased (is behaviour is understood to berelated to the formation of a compact oxide layer whichprotects the surface from wear

It is worth remarking that although the wear response ofsteel 1 was the poorest at 40degC the three studied steelsbehaved nearly the same at 200degC (is effect of equalizationat high temperature has also been reported for tool steels [2]Regarding the wear rate of the pins all specimens tested at40degC showed a much higher rate than the tool steels

By analysing the surface of the disks with electron mi-croscopy (FEG-SEMEDS) the disks of steel 2 and steel 3show debris from an oxide layer on the surface which isrelated with the low wear rate (e layer protects the disksurface against wear (Figures 7ndash10) which avoids metal-metal contact (e noncompacted wear debris particlescaused an abrasive wear on the disk surfaces

33 Contact Path After each test the profile disk of thecontact paths was characterised by measuring the maximumprofile height and depth as shown in Figures 11ndash13 wherethe vertical axis shows the height (z) and the horizontal axisshows the width (x)

By analysing the contact path the shallowest groovedepths were measured for steel 2 and steel 3 at 40degC withvalues of 7 and 10 microm respectively (Figures 11 and 12)Additionally from contact profilometry measurements it wasverified that the profile height increases due to the presence ofan oxide layer in some zones on the surface

In contrast steel 1 showed a larger amount of wearIn this case the disk surface presented numerous grooves

and zones covered by a compact oxide layer were hardlyidentified (Figure 14) (e maximum groove depth reached25 microm (Figure 13)

It is concluded that at 40degC test temperature the harderthe tool steel is the higher the abrasive wear resistancewhich explains the lower values of wear rate obtained forsteel 2 and steel 3 In this case the wear resistance is gov-erned by the hardness of the martensitic matrix Hence thelower hardness of the steel 1 disk is not enough for it towithstand the large abrasive action occurring between thedisk and the pin which leads to a high groove formation andconsequently high abrasive wear

At a 200degC test temperature the surface characteristicsand the wear rates of three tool steels were very similarDespite the large hardness of tool steels a lower wear ratevalue is related to the presence of an oxide layer that partiallycovers the disk surface thus protecting it against wear It isassumed that the formation of the oxide layer is similar forthe three tool steels (e surfaces were characterized byelectron microscopy (Figures 15 and 16) and via contactprofile measurements (Figures 17ndash19) It was observed thatthe wear of the three steel disks was abrasive with maximumdepths of the grooves between 29 and 38 microm

In relation with the wear rate of the disks at the 200degC testtemperature the results are similar with those presented byother authors [3 6] and the differences between results wereprobably caused by the different roughness of the specimensIn these works the authors observed an agglomeration andcompacting of oxidized wear debris in the tool steel surfacethat formed a protective layer against wear (is layer wasable to stand the load and avoid the metal-metal contactduring the test

In this work some zones with a protective oxide layerwere also observed In the case of steels 2 and 3 the wear rateincreased by one order of magnitude from the test per-formed at 40degC to the test at 200degC (Figures 5 and 6) In thecase of steel 1 an increase in the test temperature presenteda slight decrease in the wear rate

Regarding the analysis of the three steel surfaces testedat 200degC an accumulation of wear debris due to theabrasive action suffered by the disks (Figures 15 and 16)

Sliding direction

Oxide layer

100 μm

Figure 7 Scanning electron microscope micrograph of the steel 2disk surface tested at 40degC

Advances in Materials Science and Engineering 5

Full scale 953 cts cursor ndash0017 (761 cts)0

CW

K

Fe W

Mo

Mo VCr

Cr

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

O

Figure 8 EDS spectrum of the oxides in Figure 7

Sliding direction

Oxide layer

100 μm

Figure 9 Scanning electron microscope micrograph of the steel 3 disk surface tested at 40degC

Full scale 1054 cts cursor ndash0017 (790 cts)0

C

Fe

MoMo V

Cr

Cr

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

O

Figure 10 EDS spectrum of the oxides in Figure 9

6 Advances in Materials Science and Engineering

6420

0 20004000

6000 8000 01000

20003000

4000

ndash2ndash4ndash6

ndash6 ndash4 ndash2 0 2 4

ndash8

(a)

000 100 200 300 400 500 600550450350250150050ndash1000

ndash800

ndash600

ndash400

ndash200

000

200

400

600

800

1000

z (microm

)

x (mm)

+rms

ndashrms

(b)

Figure 11 13ree-dimensional image of the disk track of steel 2 tested at 40degC (a) 13e maximum prole depth (7 microm) (b)

5

0

0

0 500 1000 1500 2000 2500 3000 350010000

5000

ndash5

ndash10

ndash8 ndash6 ndash4 ndash2 0 2 4

ndash15

(a)

000ndash2000ndash1800ndash1600ndash1400ndash1200ndash1000ndash800ndash600ndash400ndash200

000200400600800

1000

050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 12 13ree-dimensional image of the disk track of steel 3 tested at 40degC (a) 13e maximum prole depth (10 microm) (b)

10

0

ndash10

ndash20

ndash30

ndash30 ndash25 ndash20 ndash15 ndash10 0 5 10ndash5

ndash400 1000 2000 3000 4000 5000 6000 7000 0

10002000

30004000

(a)

000ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 13 13ree-dimensional image of the disk track of steel 1 tested at 40degC (a) 13e maximum prole depth (25 microm) (b)

Advances in Materials Science and Engineering 7

was observed Despite the wear debris accumulationsome zones of the surface were covered by an oxide layer(Figure 16) It seems that the release of the oxide layerparticles causes a three-body wear that causes largeabrasive wear in the disk surface and generates deep depthgrooves

When the test temperature increased from 40degC to200degC a high amount of oxide was observed on the disksurface according to works in the literature [3 6] the oxidelayer should breaks into pieces easily below 300degC (epresence and release of oxides imply an increase in wear rateas the temperature increased A larger amount of hard oxides

Sliding direction

Oxide layer

100 μm

Figure 14 Scanning electron microscope micrograph of the steel 1 disk surface tested at 40degC

Compacted particle

Sliding direction

100 μm

Figure 15 Scanning electron microscope micrograph of the steel 1 disk surface tested at 200degC

Sliding direction

Oxide layer

100 μm

Compacted particle

Figure 16 Scanning electron microscope micrograph of the steel 2 disk surface tested at 200degC

8 Advances in Materials Science and Engineering

directly acurrenects the wear resistance of the tool steel whenworking against uncoated 22MnB5

From the obtained results it is concluded that at a test-temperature of 200degC the release of oxide particles negativelyacurrenects the wear resistance of the tool steels Also the largehardness of tool steel 2 (57HRC) was not enough for it towithstand the abrasive action of the oxide particles Tool steel1 presented the best wear behaviour even though it had thesmallest relative hardness Analysing the chemical compo-sition of the steels steel 1 presented the largest vanadiumcontent Using a scanning electron microscope (SEM modelPhillips) our EDS analysis identied the nature of the car-bides in each steel sample13e carbides present in steel 2 wererich in molybdenum and the ones in steel 3 were rich inchromium Hence the better wear behaviour of steel 1 at200degC is related with the nature of the carbides which wererich in vanadium (Figure 20) In the test at 200degC it seems that

the wear behaviour of each steel was governed by the carbidehardness present in the steel sample rather than the mar-tensitic matrix hardness (Figure 21)

When analysing the three carbides the vanadium car-bides due to their hardness and chemical nature were themost ecient at improving the wear resistance In contrastthe chromium carbides were the less ecient (Table 5)

4 Conclusions

13e results obtained from pin-on-disk tests using a SRVtribometer and temperatures of 40degC and 200degC werepresented as a method for determining the wear behaviourand the durability of the three selected hot work tool steels

13e slight decrease observed in the COF as the tem-peratures increased to 200degC was related to oxide layerformation Despite the drop in the friction coecient the

30

20

10

0

0 500 1000 1500 2000 2500 3000 3500 100005000

0

ndash10

ndash20

ndash30

ndash40

3020100ndash10ndash20ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 17 13ree-dimensional image of the disk track of steel 1 tested at 200degC (a) 13e maximum prole depth (38 microm) (b)

10

0

0

0 500 1000 1500 2000 2500 3000 3500

2000

4000

6000

8000

ndash10

ndash20

ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 18 13ree-dimensional image of the disk track of steel 2 tested at 200degC (a) 13e maximum prole depth (29 microm) (b)

Advances in Materials Science and Engineering 9

Full scale 3663 cts cursor ndash0021 (316 cts)0

CMnO

Fe

SWMoMo

Mo

VCr

Mn

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

Carbide steel 1Carbide steel 2Carbide steel 3

Figure 20 Comparison of the carbidesrsquo nature of the tool steels studied

20 μm

(a)

20 μm

(b)

20 μm

(c)

Figure 21 Detailed micrograph of steel 1 (a) steel 2 (b) and steel 3 (c)

10

ndash10

ndash20

ndash25 ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

ndash40

0

0 500 1000 1500 2000 2500 3000 3500

02000

40006000

8000

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

ndashrms

Z (μ

m)

(b)

Figure 19 13ree-dimensional image of the disk track of steel 3 tested at 200degC (a) 13e maximum prole depth (32 microm) (b)

10 Advances in Materials Science and Engineering

wear rate of the disks at 200degC was higher than that at 40degCfor the steel 2 and steel 3 samples At this temperature steel 1and steel 2 showed similar behaviour while steel 3 per-formed worse

SEM inspections confirmed that oxide layer debriswhich is unstable at temperatures less than 300degC is releasedfrom the steel surface during the SRV test (ese releasedoxides are hard abrasive particles leading to severe three-body wear and the formation of depth grooves (is wearmechanism affected each tool steel with different levels ofseverity depending on the nature of the carbides in theirmicrostructure Steel 1 and steel 2 bearing vanadium andmolybdenum carbides whose hardness is larger than those ofthe chromium carbides in steel 3 had greater wear resistanceat 200degC

It must be remarked that even though steel 1 out-performed steel 3 in terms of wear resistance at 200degC itshows lower room temperature hardness (us the HRChardness which represents an average hardness of themartensitic matrix and the carbides of the tool steel cannotbe the only guidance when designing hot forming tool steels

Conflicts of Interest

(e authors declare that they have no conflicts of interest

Acknowledgments

(e authors gratefully acknowledge the funding provided bythe Department of Research and Universities of the BasqueGovernment under Grant no IT947-16 and the University ofthe Basque Country UPVEHU under Program no UFI 1129

References

[1] O N Cora K Namiki and M Koc ldquoWear performance as-sessment of alternative stamping die materials utilizing a noveltest systemrdquo Wear vol 267 no 5ndash8 pp 1123ndash1129 2009

[2] J Hardell and B Prakash ldquoHigh-temperature friction andwear behaviour of different tool steels during sliding againstAlndashSi-coated high-strength steelrdquo Tribology Internationalvol 41 no 7 pp 663ndash671 2008

[3] J Hardell S Hernandez S Mozgovoy L PelcastreC Courbon and B Prakash ldquoEffect of oxide layers and nearsurface transformations on friction and wear during tool steeland boron steel interaction at high temperaturesrdquo Wearvol 330ndash331 pp 223ndash229 2015

[4] C Boher S Le Roux L Penazzi and C Dessain ldquoExperi-mental investigation of the tribological behavior and wearmechanisms of tool steel grades in hot stamping of a high-strength boron steelrdquo Wear vol 294-295 pp 286ndash295 2012

[5] A Ghiotti F Sgarabotto and S Bruschi ldquoA novel approach towear testing in hot stamping of high strength boron steelsheetsrdquo Wear vol 302 no 1-2 pp 1319ndash1326 2013

[6] L Deng SMozgovoy J Hardell B Prakash andMOldenburgldquoPress-hardening thermo- mechanical conditions in the contactbetween blank and toolrdquo in Proceedings of 4th InternationalConference on Hot Sheet Metal Forming of High-PerformanceSteel (CHS2) pp 293ndash300 Lulea Sweden June 2013

[7] A Ghiotti S Bruschi and F Borsetto ldquoTribological char-acteristics of high strength steel sheets under hot stampingconditionsrdquo Journal of Materials Processing Technologyvol 211 no 11 pp 1694ndash1700 2011

[8] G A Fontalvo and C Mitterer ldquo(e effect of oxide-formingalloying elements on the high temperature wear of a hot worksteelrdquo Wear vol 258 no 10 pp 1491ndash1499 2005

[9] L Pelcastre J Hardell and B Prakash ldquoGalling mechanismsduring interaction of tool steel and AlndashSi coated ultra-highstrength steel at elevated temperaturerdquo Tribology In-ternational vol 67 pp 263ndash271 2013

[10] K Dohda C Boher F Rezai-Aria and N MahayotsanunldquoTribology in metal forming at elevated temperaturesrdquoFriction vol 3 no 1 pp 1ndash27 2015

[11] G A Fontalvo R Humer C Mitterer K Sammt andI Schemmel ldquoMicrostructural aspects determining the ad-hesive wear of tool steelsrdquo Wear vol 260 no 9-10pp 1028ndash1034 2006

[12] I Hussainova E Hamed and I Jasiuk ldquoNanoindentationtesting and modeling of chromium-carbide-based compos-itesrdquo Mechanics of Composite Materials vol 46 no 6pp 667ndash678 2011

[13] Y Z Liu Y H Jiang J Feng and R Zhou ldquoElasticityelectronic properties and hardness of MoC investigated byfirst principles calculationsrdquo Physica B Condensed Mattervol 419 pp 45ndash50 2013

[14] L Wu T Yao Y Wang J Zhang F Xiao and B LiaoldquoUnderstanding the mechanical properties of vanadiumcarbides nano-indentation measurement and first-principlescalculationsrdquo Journal of Alloys and Compounds vol 548pp 60ndash64 2013

Table 5 Different carbides hardness

Nature of the carbide Hardness (GPa)Chromium carbides 102ndash20 [12]Molybdenum carbides 1339ndash2887 [13]Vanadium carbides 117ndash315 [14]

Advances in Materials Science and Engineering 11

CorrosionInternational Journal of

Hindawiwwwhindawicom Volume 2018

Advances in

Materials Science and EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Journal of

Chemistry

Analytical ChemistryInternational Journal of

Hindawiwwwhindawicom Volume 2018

ScienticaHindawiwwwhindawicom Volume 2018

Polymer ScienceInternational Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Advances in Condensed Matter Physics

Hindawiwwwhindawicom Volume 2018

International Journal of

BiomaterialsHindawiwwwhindawicom

Journal ofEngineeringVolume 2018

Applied ChemistryJournal of

Hindawiwwwhindawicom Volume 2018

NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Hindawiwwwhindawicom Volume 2018

High Energy PhysicsAdvances in

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

TribologyAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

ChemistryAdvances in

Hindawiwwwhindawicom Volume 2018

Advances inPhysical Chemistry

Hindawiwwwhindawicom Volume 2018

BioMed Research InternationalMaterials

Journal of

Hindawiwwwhindawicom Volume 2018

Na

nom

ate

ria

ls

Hindawiwwwhindawicom Volume 2018

Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

Full scale 953 cts cursor ndash0017 (761 cts)0

CW

K

Fe W

Mo

Mo VCr

Cr

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

O

Figure 8 EDS spectrum of the oxides in Figure 7

Sliding direction

Oxide layer

100 μm

Figure 9 Scanning electron microscope micrograph of the steel 3 disk surface tested at 40degC

Full scale 1054 cts cursor ndash0017 (790 cts)0

C

Fe

MoMo V

Cr

Cr

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

O

Figure 10 EDS spectrum of the oxides in Figure 9

6 Advances in Materials Science and Engineering

6420

0 20004000

6000 8000 01000

20003000

4000

ndash2ndash4ndash6

ndash6 ndash4 ndash2 0 2 4

ndash8

(a)

000 100 200 300 400 500 600550450350250150050ndash1000

ndash800

ndash600

ndash400

ndash200

000

200

400

600

800

1000

z (microm

)

x (mm)

+rms

ndashrms

(b)

Figure 11 13ree-dimensional image of the disk track of steel 2 tested at 40degC (a) 13e maximum prole depth (7 microm) (b)

5

0

0

0 500 1000 1500 2000 2500 3000 350010000

5000

ndash5

ndash10

ndash8 ndash6 ndash4 ndash2 0 2 4

ndash15

(a)

000ndash2000ndash1800ndash1600ndash1400ndash1200ndash1000ndash800ndash600ndash400ndash200

000200400600800

1000

050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 12 13ree-dimensional image of the disk track of steel 3 tested at 40degC (a) 13e maximum prole depth (10 microm) (b)

10

0

ndash10

ndash20

ndash30

ndash30 ndash25 ndash20 ndash15 ndash10 0 5 10ndash5

ndash400 1000 2000 3000 4000 5000 6000 7000 0

10002000

30004000

(a)

000ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 13 13ree-dimensional image of the disk track of steel 1 tested at 40degC (a) 13e maximum prole depth (25 microm) (b)

Advances in Materials Science and Engineering 7

was observed Despite the wear debris accumulationsome zones of the surface were covered by an oxide layer(Figure 16) It seems that the release of the oxide layerparticles causes a three-body wear that causes largeabrasive wear in the disk surface and generates deep depthgrooves

When the test temperature increased from 40degC to200degC a high amount of oxide was observed on the disksurface according to works in the literature [3 6] the oxidelayer should breaks into pieces easily below 300degC (epresence and release of oxides imply an increase in wear rateas the temperature increased A larger amount of hard oxides

Sliding direction

Oxide layer

100 μm

Figure 14 Scanning electron microscope micrograph of the steel 1 disk surface tested at 40degC

Compacted particle

Sliding direction

100 μm

Figure 15 Scanning electron microscope micrograph of the steel 1 disk surface tested at 200degC

Sliding direction

Oxide layer

100 μm

Compacted particle

Figure 16 Scanning electron microscope micrograph of the steel 2 disk surface tested at 200degC

8 Advances in Materials Science and Engineering

directly acurrenects the wear resistance of the tool steel whenworking against uncoated 22MnB5

From the obtained results it is concluded that at a test-temperature of 200degC the release of oxide particles negativelyacurrenects the wear resistance of the tool steels Also the largehardness of tool steel 2 (57HRC) was not enough for it towithstand the abrasive action of the oxide particles Tool steel1 presented the best wear behaviour even though it had thesmallest relative hardness Analysing the chemical compo-sition of the steels steel 1 presented the largest vanadiumcontent Using a scanning electron microscope (SEM modelPhillips) our EDS analysis identied the nature of the car-bides in each steel sample13e carbides present in steel 2 wererich in molybdenum and the ones in steel 3 were rich inchromium Hence the better wear behaviour of steel 1 at200degC is related with the nature of the carbides which wererich in vanadium (Figure 20) In the test at 200degC it seems that

the wear behaviour of each steel was governed by the carbidehardness present in the steel sample rather than the mar-tensitic matrix hardness (Figure 21)

When analysing the three carbides the vanadium car-bides due to their hardness and chemical nature were themost ecient at improving the wear resistance In contrastthe chromium carbides were the less ecient (Table 5)

4 Conclusions

13e results obtained from pin-on-disk tests using a SRVtribometer and temperatures of 40degC and 200degC werepresented as a method for determining the wear behaviourand the durability of the three selected hot work tool steels

13e slight decrease observed in the COF as the tem-peratures increased to 200degC was related to oxide layerformation Despite the drop in the friction coecient the

30

20

10

0

0 500 1000 1500 2000 2500 3000 3500 100005000

0

ndash10

ndash20

ndash30

ndash40

3020100ndash10ndash20ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 17 13ree-dimensional image of the disk track of steel 1 tested at 200degC (a) 13e maximum prole depth (38 microm) (b)

10

0

0

0 500 1000 1500 2000 2500 3000 3500

2000

4000

6000

8000

ndash10

ndash20

ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 18 13ree-dimensional image of the disk track of steel 2 tested at 200degC (a) 13e maximum prole depth (29 microm) (b)

Advances in Materials Science and Engineering 9

Full scale 3663 cts cursor ndash0021 (316 cts)0

CMnO

Fe

SWMoMo

Mo

VCr

Mn

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

Carbide steel 1Carbide steel 2Carbide steel 3

Figure 20 Comparison of the carbidesrsquo nature of the tool steels studied

20 μm

(a)

20 μm

(b)

20 μm

(c)

Figure 21 Detailed micrograph of steel 1 (a) steel 2 (b) and steel 3 (c)

10

ndash10

ndash20

ndash25 ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

ndash40

0

0 500 1000 1500 2000 2500 3000 3500

02000

40006000

8000

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

ndashrms

Z (μ

m)

(b)

Figure 19 13ree-dimensional image of the disk track of steel 3 tested at 200degC (a) 13e maximum prole depth (32 microm) (b)

10 Advances in Materials Science and Engineering

wear rate of the disks at 200degC was higher than that at 40degCfor the steel 2 and steel 3 samples At this temperature steel 1and steel 2 showed similar behaviour while steel 3 per-formed worse

SEM inspections confirmed that oxide layer debriswhich is unstable at temperatures less than 300degC is releasedfrom the steel surface during the SRV test (ese releasedoxides are hard abrasive particles leading to severe three-body wear and the formation of depth grooves (is wearmechanism affected each tool steel with different levels ofseverity depending on the nature of the carbides in theirmicrostructure Steel 1 and steel 2 bearing vanadium andmolybdenum carbides whose hardness is larger than those ofthe chromium carbides in steel 3 had greater wear resistanceat 200degC

It must be remarked that even though steel 1 out-performed steel 3 in terms of wear resistance at 200degC itshows lower room temperature hardness (us the HRChardness which represents an average hardness of themartensitic matrix and the carbides of the tool steel cannotbe the only guidance when designing hot forming tool steels

Conflicts of Interest

(e authors declare that they have no conflicts of interest

Acknowledgments

(e authors gratefully acknowledge the funding provided bythe Department of Research and Universities of the BasqueGovernment under Grant no IT947-16 and the University ofthe Basque Country UPVEHU under Program no UFI 1129

References

[1] O N Cora K Namiki and M Koc ldquoWear performance as-sessment of alternative stamping die materials utilizing a noveltest systemrdquo Wear vol 267 no 5ndash8 pp 1123ndash1129 2009

[2] J Hardell and B Prakash ldquoHigh-temperature friction andwear behaviour of different tool steels during sliding againstAlndashSi-coated high-strength steelrdquo Tribology Internationalvol 41 no 7 pp 663ndash671 2008

[3] J Hardell S Hernandez S Mozgovoy L PelcastreC Courbon and B Prakash ldquoEffect of oxide layers and nearsurface transformations on friction and wear during tool steeland boron steel interaction at high temperaturesrdquo Wearvol 330ndash331 pp 223ndash229 2015

[4] C Boher S Le Roux L Penazzi and C Dessain ldquoExperi-mental investigation of the tribological behavior and wearmechanisms of tool steel grades in hot stamping of a high-strength boron steelrdquo Wear vol 294-295 pp 286ndash295 2012

[5] A Ghiotti F Sgarabotto and S Bruschi ldquoA novel approach towear testing in hot stamping of high strength boron steelsheetsrdquo Wear vol 302 no 1-2 pp 1319ndash1326 2013

[6] L Deng SMozgovoy J Hardell B Prakash andMOldenburgldquoPress-hardening thermo- mechanical conditions in the contactbetween blank and toolrdquo in Proceedings of 4th InternationalConference on Hot Sheet Metal Forming of High-PerformanceSteel (CHS2) pp 293ndash300 Lulea Sweden June 2013

[7] A Ghiotti S Bruschi and F Borsetto ldquoTribological char-acteristics of high strength steel sheets under hot stampingconditionsrdquo Journal of Materials Processing Technologyvol 211 no 11 pp 1694ndash1700 2011

[8] G A Fontalvo and C Mitterer ldquo(e effect of oxide-formingalloying elements on the high temperature wear of a hot worksteelrdquo Wear vol 258 no 10 pp 1491ndash1499 2005

[9] L Pelcastre J Hardell and B Prakash ldquoGalling mechanismsduring interaction of tool steel and AlndashSi coated ultra-highstrength steel at elevated temperaturerdquo Tribology In-ternational vol 67 pp 263ndash271 2013

[10] K Dohda C Boher F Rezai-Aria and N MahayotsanunldquoTribology in metal forming at elevated temperaturesrdquoFriction vol 3 no 1 pp 1ndash27 2015

[11] G A Fontalvo R Humer C Mitterer K Sammt andI Schemmel ldquoMicrostructural aspects determining the ad-hesive wear of tool steelsrdquo Wear vol 260 no 9-10pp 1028ndash1034 2006

[12] I Hussainova E Hamed and I Jasiuk ldquoNanoindentationtesting and modeling of chromium-carbide-based compos-itesrdquo Mechanics of Composite Materials vol 46 no 6pp 667ndash678 2011

[13] Y Z Liu Y H Jiang J Feng and R Zhou ldquoElasticityelectronic properties and hardness of MoC investigated byfirst principles calculationsrdquo Physica B Condensed Mattervol 419 pp 45ndash50 2013

[14] L Wu T Yao Y Wang J Zhang F Xiao and B LiaoldquoUnderstanding the mechanical properties of vanadiumcarbides nano-indentation measurement and first-principlescalculationsrdquo Journal of Alloys and Compounds vol 548pp 60ndash64 2013

Table 5 Different carbides hardness

Nature of the carbide Hardness (GPa)Chromium carbides 102ndash20 [12]Molybdenum carbides 1339ndash2887 [13]Vanadium carbides 117ndash315 [14]

Advances in Materials Science and Engineering 11

CorrosionInternational Journal of

Hindawiwwwhindawicom Volume 2018

Advances in

Materials Science and EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Journal of

Chemistry

Analytical ChemistryInternational Journal of

Hindawiwwwhindawicom Volume 2018

ScienticaHindawiwwwhindawicom Volume 2018

Polymer ScienceInternational Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Advances in Condensed Matter Physics

Hindawiwwwhindawicom Volume 2018

International Journal of

BiomaterialsHindawiwwwhindawicom

Journal ofEngineeringVolume 2018

Applied ChemistryJournal of

Hindawiwwwhindawicom Volume 2018

NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Hindawiwwwhindawicom Volume 2018

High Energy PhysicsAdvances in

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

TribologyAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

ChemistryAdvances in

Hindawiwwwhindawicom Volume 2018

Advances inPhysical Chemistry

Hindawiwwwhindawicom Volume 2018

BioMed Research InternationalMaterials

Journal of

Hindawiwwwhindawicom Volume 2018

Na

nom

ate

ria

ls

Hindawiwwwhindawicom Volume 2018

Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

6420

0 20004000

6000 8000 01000

20003000

4000

ndash2ndash4ndash6

ndash6 ndash4 ndash2 0 2 4

ndash8

(a)

000 100 200 300 400 500 600550450350250150050ndash1000

ndash800

ndash600

ndash400

ndash200

000

200

400

600

800

1000

z (microm

)

x (mm)

+rms

ndashrms

(b)

Figure 11 13ree-dimensional image of the disk track of steel 2 tested at 40degC (a) 13e maximum prole depth (7 microm) (b)

5

0

0

0 500 1000 1500 2000 2500 3000 350010000

5000

ndash5

ndash10

ndash8 ndash6 ndash4 ndash2 0 2 4

ndash15

(a)

000ndash2000ndash1800ndash1600ndash1400ndash1200ndash1000ndash800ndash600ndash400ndash200

000200400600800

1000

050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 12 13ree-dimensional image of the disk track of steel 3 tested at 40degC (a) 13e maximum prole depth (10 microm) (b)

10

0

ndash10

ndash20

ndash30

ndash30 ndash25 ndash20 ndash15 ndash10 0 5 10ndash5

ndash400 1000 2000 3000 4000 5000 6000 7000 0

10002000

30004000

(a)

000ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 13 13ree-dimensional image of the disk track of steel 1 tested at 40degC (a) 13e maximum prole depth (25 microm) (b)

Advances in Materials Science and Engineering 7

was observed Despite the wear debris accumulationsome zones of the surface were covered by an oxide layer(Figure 16) It seems that the release of the oxide layerparticles causes a three-body wear that causes largeabrasive wear in the disk surface and generates deep depthgrooves

When the test temperature increased from 40degC to200degC a high amount of oxide was observed on the disksurface according to works in the literature [3 6] the oxidelayer should breaks into pieces easily below 300degC (epresence and release of oxides imply an increase in wear rateas the temperature increased A larger amount of hard oxides

Sliding direction

Oxide layer

100 μm

Figure 14 Scanning electron microscope micrograph of the steel 1 disk surface tested at 40degC

Compacted particle

Sliding direction

100 μm

Figure 15 Scanning electron microscope micrograph of the steel 1 disk surface tested at 200degC

Sliding direction

Oxide layer

100 μm

Compacted particle

Figure 16 Scanning electron microscope micrograph of the steel 2 disk surface tested at 200degC

8 Advances in Materials Science and Engineering

directly acurrenects the wear resistance of the tool steel whenworking against uncoated 22MnB5

From the obtained results it is concluded that at a test-temperature of 200degC the release of oxide particles negativelyacurrenects the wear resistance of the tool steels Also the largehardness of tool steel 2 (57HRC) was not enough for it towithstand the abrasive action of the oxide particles Tool steel1 presented the best wear behaviour even though it had thesmallest relative hardness Analysing the chemical compo-sition of the steels steel 1 presented the largest vanadiumcontent Using a scanning electron microscope (SEM modelPhillips) our EDS analysis identied the nature of the car-bides in each steel sample13e carbides present in steel 2 wererich in molybdenum and the ones in steel 3 were rich inchromium Hence the better wear behaviour of steel 1 at200degC is related with the nature of the carbides which wererich in vanadium (Figure 20) In the test at 200degC it seems that

the wear behaviour of each steel was governed by the carbidehardness present in the steel sample rather than the mar-tensitic matrix hardness (Figure 21)

When analysing the three carbides the vanadium car-bides due to their hardness and chemical nature were themost ecient at improving the wear resistance In contrastthe chromium carbides were the less ecient (Table 5)

4 Conclusions

13e results obtained from pin-on-disk tests using a SRVtribometer and temperatures of 40degC and 200degC werepresented as a method for determining the wear behaviourand the durability of the three selected hot work tool steels

13e slight decrease observed in the COF as the tem-peratures increased to 200degC was related to oxide layerformation Despite the drop in the friction coecient the

30

20

10

0

0 500 1000 1500 2000 2500 3000 3500 100005000

0

ndash10

ndash20

ndash30

ndash40

3020100ndash10ndash20ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 17 13ree-dimensional image of the disk track of steel 1 tested at 200degC (a) 13e maximum prole depth (38 microm) (b)

10

0

0

0 500 1000 1500 2000 2500 3000 3500

2000

4000

6000

8000

ndash10

ndash20

ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 18 13ree-dimensional image of the disk track of steel 2 tested at 200degC (a) 13e maximum prole depth (29 microm) (b)

Advances in Materials Science and Engineering 9

Full scale 3663 cts cursor ndash0021 (316 cts)0

CMnO

Fe

SWMoMo

Mo

VCr

Mn

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

Carbide steel 1Carbide steel 2Carbide steel 3

Figure 20 Comparison of the carbidesrsquo nature of the tool steels studied

20 μm

(a)

20 μm

(b)

20 μm

(c)

Figure 21 Detailed micrograph of steel 1 (a) steel 2 (b) and steel 3 (c)

10

ndash10

ndash20

ndash25 ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

ndash40

0

0 500 1000 1500 2000 2500 3000 3500

02000

40006000

8000

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

ndashrms

Z (μ

m)

(b)

Figure 19 13ree-dimensional image of the disk track of steel 3 tested at 200degC (a) 13e maximum prole depth (32 microm) (b)

10 Advances in Materials Science and Engineering

wear rate of the disks at 200degC was higher than that at 40degCfor the steel 2 and steel 3 samples At this temperature steel 1and steel 2 showed similar behaviour while steel 3 per-formed worse

SEM inspections confirmed that oxide layer debriswhich is unstable at temperatures less than 300degC is releasedfrom the steel surface during the SRV test (ese releasedoxides are hard abrasive particles leading to severe three-body wear and the formation of depth grooves (is wearmechanism affected each tool steel with different levels ofseverity depending on the nature of the carbides in theirmicrostructure Steel 1 and steel 2 bearing vanadium andmolybdenum carbides whose hardness is larger than those ofthe chromium carbides in steel 3 had greater wear resistanceat 200degC

It must be remarked that even though steel 1 out-performed steel 3 in terms of wear resistance at 200degC itshows lower room temperature hardness (us the HRChardness which represents an average hardness of themartensitic matrix and the carbides of the tool steel cannotbe the only guidance when designing hot forming tool steels

Conflicts of Interest

(e authors declare that they have no conflicts of interest

Acknowledgments

(e authors gratefully acknowledge the funding provided bythe Department of Research and Universities of the BasqueGovernment under Grant no IT947-16 and the University ofthe Basque Country UPVEHU under Program no UFI 1129

References

[1] O N Cora K Namiki and M Koc ldquoWear performance as-sessment of alternative stamping die materials utilizing a noveltest systemrdquo Wear vol 267 no 5ndash8 pp 1123ndash1129 2009

[2] J Hardell and B Prakash ldquoHigh-temperature friction andwear behaviour of different tool steels during sliding againstAlndashSi-coated high-strength steelrdquo Tribology Internationalvol 41 no 7 pp 663ndash671 2008

[3] J Hardell S Hernandez S Mozgovoy L PelcastreC Courbon and B Prakash ldquoEffect of oxide layers and nearsurface transformations on friction and wear during tool steeland boron steel interaction at high temperaturesrdquo Wearvol 330ndash331 pp 223ndash229 2015

[4] C Boher S Le Roux L Penazzi and C Dessain ldquoExperi-mental investigation of the tribological behavior and wearmechanisms of tool steel grades in hot stamping of a high-strength boron steelrdquo Wear vol 294-295 pp 286ndash295 2012

[5] A Ghiotti F Sgarabotto and S Bruschi ldquoA novel approach towear testing in hot stamping of high strength boron steelsheetsrdquo Wear vol 302 no 1-2 pp 1319ndash1326 2013

[6] L Deng SMozgovoy J Hardell B Prakash andMOldenburgldquoPress-hardening thermo- mechanical conditions in the contactbetween blank and toolrdquo in Proceedings of 4th InternationalConference on Hot Sheet Metal Forming of High-PerformanceSteel (CHS2) pp 293ndash300 Lulea Sweden June 2013

[7] A Ghiotti S Bruschi and F Borsetto ldquoTribological char-acteristics of high strength steel sheets under hot stampingconditionsrdquo Journal of Materials Processing Technologyvol 211 no 11 pp 1694ndash1700 2011

[8] G A Fontalvo and C Mitterer ldquo(e effect of oxide-formingalloying elements on the high temperature wear of a hot worksteelrdquo Wear vol 258 no 10 pp 1491ndash1499 2005

[9] L Pelcastre J Hardell and B Prakash ldquoGalling mechanismsduring interaction of tool steel and AlndashSi coated ultra-highstrength steel at elevated temperaturerdquo Tribology In-ternational vol 67 pp 263ndash271 2013

[10] K Dohda C Boher F Rezai-Aria and N MahayotsanunldquoTribology in metal forming at elevated temperaturesrdquoFriction vol 3 no 1 pp 1ndash27 2015

[11] G A Fontalvo R Humer C Mitterer K Sammt andI Schemmel ldquoMicrostructural aspects determining the ad-hesive wear of tool steelsrdquo Wear vol 260 no 9-10pp 1028ndash1034 2006

[12] I Hussainova E Hamed and I Jasiuk ldquoNanoindentationtesting and modeling of chromium-carbide-based compos-itesrdquo Mechanics of Composite Materials vol 46 no 6pp 667ndash678 2011

[13] Y Z Liu Y H Jiang J Feng and R Zhou ldquoElasticityelectronic properties and hardness of MoC investigated byfirst principles calculationsrdquo Physica B Condensed Mattervol 419 pp 45ndash50 2013

[14] L Wu T Yao Y Wang J Zhang F Xiao and B LiaoldquoUnderstanding the mechanical properties of vanadiumcarbides nano-indentation measurement and first-principlescalculationsrdquo Journal of Alloys and Compounds vol 548pp 60ndash64 2013

Table 5 Different carbides hardness

Nature of the carbide Hardness (GPa)Chromium carbides 102ndash20 [12]Molybdenum carbides 1339ndash2887 [13]Vanadium carbides 117ndash315 [14]

Advances in Materials Science and Engineering 11

CorrosionInternational Journal of

Hindawiwwwhindawicom Volume 2018

Advances in

Materials Science and EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Journal of

Chemistry

Analytical ChemistryInternational Journal of

Hindawiwwwhindawicom Volume 2018

ScienticaHindawiwwwhindawicom Volume 2018

Polymer ScienceInternational Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Advances in Condensed Matter Physics

Hindawiwwwhindawicom Volume 2018

International Journal of

BiomaterialsHindawiwwwhindawicom

Journal ofEngineeringVolume 2018

Applied ChemistryJournal of

Hindawiwwwhindawicom Volume 2018

NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Hindawiwwwhindawicom Volume 2018

High Energy PhysicsAdvances in

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

TribologyAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

ChemistryAdvances in

Hindawiwwwhindawicom Volume 2018

Advances inPhysical Chemistry

Hindawiwwwhindawicom Volume 2018

BioMed Research InternationalMaterials

Journal of

Hindawiwwwhindawicom Volume 2018

Na

nom

ate

ria

ls

Hindawiwwwhindawicom Volume 2018

Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

was observed Despite the wear debris accumulationsome zones of the surface were covered by an oxide layer(Figure 16) It seems that the release of the oxide layerparticles causes a three-body wear that causes largeabrasive wear in the disk surface and generates deep depthgrooves

When the test temperature increased from 40degC to200degC a high amount of oxide was observed on the disksurface according to works in the literature [3 6] the oxidelayer should breaks into pieces easily below 300degC (epresence and release of oxides imply an increase in wear rateas the temperature increased A larger amount of hard oxides

Sliding direction

Oxide layer

100 μm

Figure 14 Scanning electron microscope micrograph of the steel 1 disk surface tested at 40degC

Compacted particle

Sliding direction

100 μm

Figure 15 Scanning electron microscope micrograph of the steel 1 disk surface tested at 200degC

Sliding direction

Oxide layer

100 μm

Compacted particle

Figure 16 Scanning electron microscope micrograph of the steel 2 disk surface tested at 200degC

8 Advances in Materials Science and Engineering

directly acurrenects the wear resistance of the tool steel whenworking against uncoated 22MnB5

From the obtained results it is concluded that at a test-temperature of 200degC the release of oxide particles negativelyacurrenects the wear resistance of the tool steels Also the largehardness of tool steel 2 (57HRC) was not enough for it towithstand the abrasive action of the oxide particles Tool steel1 presented the best wear behaviour even though it had thesmallest relative hardness Analysing the chemical compo-sition of the steels steel 1 presented the largest vanadiumcontent Using a scanning electron microscope (SEM modelPhillips) our EDS analysis identied the nature of the car-bides in each steel sample13e carbides present in steel 2 wererich in molybdenum and the ones in steel 3 were rich inchromium Hence the better wear behaviour of steel 1 at200degC is related with the nature of the carbides which wererich in vanadium (Figure 20) In the test at 200degC it seems that

the wear behaviour of each steel was governed by the carbidehardness present in the steel sample rather than the mar-tensitic matrix hardness (Figure 21)

When analysing the three carbides the vanadium car-bides due to their hardness and chemical nature were themost ecient at improving the wear resistance In contrastthe chromium carbides were the less ecient (Table 5)

4 Conclusions

13e results obtained from pin-on-disk tests using a SRVtribometer and temperatures of 40degC and 200degC werepresented as a method for determining the wear behaviourand the durability of the three selected hot work tool steels

13e slight decrease observed in the COF as the tem-peratures increased to 200degC was related to oxide layerformation Despite the drop in the friction coecient the

30

20

10

0

0 500 1000 1500 2000 2500 3000 3500 100005000

0

ndash10

ndash20

ndash30

ndash40

3020100ndash10ndash20ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 17 13ree-dimensional image of the disk track of steel 1 tested at 200degC (a) 13e maximum prole depth (38 microm) (b)

10

0

0

0 500 1000 1500 2000 2500 3000 3500

2000

4000

6000

8000

ndash10

ndash20

ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 18 13ree-dimensional image of the disk track of steel 2 tested at 200degC (a) 13e maximum prole depth (29 microm) (b)

Advances in Materials Science and Engineering 9

Full scale 3663 cts cursor ndash0021 (316 cts)0

CMnO

Fe

SWMoMo

Mo

VCr

Mn

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

Carbide steel 1Carbide steel 2Carbide steel 3

Figure 20 Comparison of the carbidesrsquo nature of the tool steels studied

20 μm

(a)

20 μm

(b)

20 μm

(c)

Figure 21 Detailed micrograph of steel 1 (a) steel 2 (b) and steel 3 (c)

10

ndash10

ndash20

ndash25 ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

ndash40

0

0 500 1000 1500 2000 2500 3000 3500

02000

40006000

8000

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

ndashrms

Z (μ

m)

(b)

Figure 19 13ree-dimensional image of the disk track of steel 3 tested at 200degC (a) 13e maximum prole depth (32 microm) (b)

10 Advances in Materials Science and Engineering

wear rate of the disks at 200degC was higher than that at 40degCfor the steel 2 and steel 3 samples At this temperature steel 1and steel 2 showed similar behaviour while steel 3 per-formed worse

SEM inspections confirmed that oxide layer debriswhich is unstable at temperatures less than 300degC is releasedfrom the steel surface during the SRV test (ese releasedoxides are hard abrasive particles leading to severe three-body wear and the formation of depth grooves (is wearmechanism affected each tool steel with different levels ofseverity depending on the nature of the carbides in theirmicrostructure Steel 1 and steel 2 bearing vanadium andmolybdenum carbides whose hardness is larger than those ofthe chromium carbides in steel 3 had greater wear resistanceat 200degC

It must be remarked that even though steel 1 out-performed steel 3 in terms of wear resistance at 200degC itshows lower room temperature hardness (us the HRChardness which represents an average hardness of themartensitic matrix and the carbides of the tool steel cannotbe the only guidance when designing hot forming tool steels

Conflicts of Interest

(e authors declare that they have no conflicts of interest

Acknowledgments

(e authors gratefully acknowledge the funding provided bythe Department of Research and Universities of the BasqueGovernment under Grant no IT947-16 and the University ofthe Basque Country UPVEHU under Program no UFI 1129

References

[1] O N Cora K Namiki and M Koc ldquoWear performance as-sessment of alternative stamping die materials utilizing a noveltest systemrdquo Wear vol 267 no 5ndash8 pp 1123ndash1129 2009

[2] J Hardell and B Prakash ldquoHigh-temperature friction andwear behaviour of different tool steels during sliding againstAlndashSi-coated high-strength steelrdquo Tribology Internationalvol 41 no 7 pp 663ndash671 2008

[3] J Hardell S Hernandez S Mozgovoy L PelcastreC Courbon and B Prakash ldquoEffect of oxide layers and nearsurface transformations on friction and wear during tool steeland boron steel interaction at high temperaturesrdquo Wearvol 330ndash331 pp 223ndash229 2015

[4] C Boher S Le Roux L Penazzi and C Dessain ldquoExperi-mental investigation of the tribological behavior and wearmechanisms of tool steel grades in hot stamping of a high-strength boron steelrdquo Wear vol 294-295 pp 286ndash295 2012

[5] A Ghiotti F Sgarabotto and S Bruschi ldquoA novel approach towear testing in hot stamping of high strength boron steelsheetsrdquo Wear vol 302 no 1-2 pp 1319ndash1326 2013

[6] L Deng SMozgovoy J Hardell B Prakash andMOldenburgldquoPress-hardening thermo- mechanical conditions in the contactbetween blank and toolrdquo in Proceedings of 4th InternationalConference on Hot Sheet Metal Forming of High-PerformanceSteel (CHS2) pp 293ndash300 Lulea Sweden June 2013

[7] A Ghiotti S Bruschi and F Borsetto ldquoTribological char-acteristics of high strength steel sheets under hot stampingconditionsrdquo Journal of Materials Processing Technologyvol 211 no 11 pp 1694ndash1700 2011

[8] G A Fontalvo and C Mitterer ldquo(e effect of oxide-formingalloying elements on the high temperature wear of a hot worksteelrdquo Wear vol 258 no 10 pp 1491ndash1499 2005

[9] L Pelcastre J Hardell and B Prakash ldquoGalling mechanismsduring interaction of tool steel and AlndashSi coated ultra-highstrength steel at elevated temperaturerdquo Tribology In-ternational vol 67 pp 263ndash271 2013

[10] K Dohda C Boher F Rezai-Aria and N MahayotsanunldquoTribology in metal forming at elevated temperaturesrdquoFriction vol 3 no 1 pp 1ndash27 2015

[11] G A Fontalvo R Humer C Mitterer K Sammt andI Schemmel ldquoMicrostructural aspects determining the ad-hesive wear of tool steelsrdquo Wear vol 260 no 9-10pp 1028ndash1034 2006

[12] I Hussainova E Hamed and I Jasiuk ldquoNanoindentationtesting and modeling of chromium-carbide-based compos-itesrdquo Mechanics of Composite Materials vol 46 no 6pp 667ndash678 2011

[13] Y Z Liu Y H Jiang J Feng and R Zhou ldquoElasticityelectronic properties and hardness of MoC investigated byfirst principles calculationsrdquo Physica B Condensed Mattervol 419 pp 45ndash50 2013

[14] L Wu T Yao Y Wang J Zhang F Xiao and B LiaoldquoUnderstanding the mechanical properties of vanadiumcarbides nano-indentation measurement and first-principlescalculationsrdquo Journal of Alloys and Compounds vol 548pp 60ndash64 2013

Table 5 Different carbides hardness

Nature of the carbide Hardness (GPa)Chromium carbides 102ndash20 [12]Molybdenum carbides 1339ndash2887 [13]Vanadium carbides 117ndash315 [14]

Advances in Materials Science and Engineering 11

CorrosionInternational Journal of

Hindawiwwwhindawicom Volume 2018

Advances in

Materials Science and EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Journal of

Chemistry

Analytical ChemistryInternational Journal of

Hindawiwwwhindawicom Volume 2018

ScienticaHindawiwwwhindawicom Volume 2018

Polymer ScienceInternational Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Advances in Condensed Matter Physics

Hindawiwwwhindawicom Volume 2018

International Journal of

BiomaterialsHindawiwwwhindawicom

Journal ofEngineeringVolume 2018

Applied ChemistryJournal of

Hindawiwwwhindawicom Volume 2018

NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Hindawiwwwhindawicom Volume 2018

High Energy PhysicsAdvances in

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

TribologyAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

ChemistryAdvances in

Hindawiwwwhindawicom Volume 2018

Advances inPhysical Chemistry

Hindawiwwwhindawicom Volume 2018

BioMed Research InternationalMaterials

Journal of

Hindawiwwwhindawicom Volume 2018

Na

nom

ate

ria

ls

Hindawiwwwhindawicom Volume 2018

Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

directly acurrenects the wear resistance of the tool steel whenworking against uncoated 22MnB5

From the obtained results it is concluded that at a test-temperature of 200degC the release of oxide particles negativelyacurrenects the wear resistance of the tool steels Also the largehardness of tool steel 2 (57HRC) was not enough for it towithstand the abrasive action of the oxide particles Tool steel1 presented the best wear behaviour even though it had thesmallest relative hardness Analysing the chemical compo-sition of the steels steel 1 presented the largest vanadiumcontent Using a scanning electron microscope (SEM modelPhillips) our EDS analysis identied the nature of the car-bides in each steel sample13e carbides present in steel 2 wererich in molybdenum and the ones in steel 3 were rich inchromium Hence the better wear behaviour of steel 1 at200degC is related with the nature of the carbides which wererich in vanadium (Figure 20) In the test at 200degC it seems that

the wear behaviour of each steel was governed by the carbidehardness present in the steel sample rather than the mar-tensitic matrix hardness (Figure 21)

When analysing the three carbides the vanadium car-bides due to their hardness and chemical nature were themost ecient at improving the wear resistance In contrastthe chromium carbides were the less ecient (Table 5)

4 Conclusions

13e results obtained from pin-on-disk tests using a SRVtribometer and temperatures of 40degC and 200degC werepresented as a method for determining the wear behaviourand the durability of the three selected hot work tool steels

13e slight decrease observed in the COF as the tem-peratures increased to 200degC was related to oxide layerformation Despite the drop in the friction coecient the

30

20

10

0

0 500 1000 1500 2000 2500 3000 3500 100005000

0

ndash10

ndash20

ndash30

ndash40

3020100ndash10ndash20ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 17 13ree-dimensional image of the disk track of steel 1 tested at 200degC (a) 13e maximum prole depth (38 microm) (b)

10

0

0

0 500 1000 1500 2000 2500 3000 3500

2000

4000

6000

8000

ndash10

ndash20

ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

+rms

ndashrms

z (μm

)

(b)

Figure 18 13ree-dimensional image of the disk track of steel 2 tested at 200degC (a) 13e maximum prole depth (29 microm) (b)

Advances in Materials Science and Engineering 9

Full scale 3663 cts cursor ndash0021 (316 cts)0

CMnO

Fe

SWMoMo

Mo

VCr

Mn

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

Carbide steel 1Carbide steel 2Carbide steel 3

Figure 20 Comparison of the carbidesrsquo nature of the tool steels studied

20 μm

(a)

20 μm

(b)

20 μm

(c)

Figure 21 Detailed micrograph of steel 1 (a) steel 2 (b) and steel 3 (c)

10

ndash10

ndash20

ndash25 ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

ndash40

0

0 500 1000 1500 2000 2500 3000 3500

02000

40006000

8000

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

ndashrms

Z (μ

m)

(b)

Figure 19 13ree-dimensional image of the disk track of steel 3 tested at 200degC (a) 13e maximum prole depth (32 microm) (b)

10 Advances in Materials Science and Engineering

wear rate of the disks at 200degC was higher than that at 40degCfor the steel 2 and steel 3 samples At this temperature steel 1and steel 2 showed similar behaviour while steel 3 per-formed worse

SEM inspections confirmed that oxide layer debriswhich is unstable at temperatures less than 300degC is releasedfrom the steel surface during the SRV test (ese releasedoxides are hard abrasive particles leading to severe three-body wear and the formation of depth grooves (is wearmechanism affected each tool steel with different levels ofseverity depending on the nature of the carbides in theirmicrostructure Steel 1 and steel 2 bearing vanadium andmolybdenum carbides whose hardness is larger than those ofthe chromium carbides in steel 3 had greater wear resistanceat 200degC

It must be remarked that even though steel 1 out-performed steel 3 in terms of wear resistance at 200degC itshows lower room temperature hardness (us the HRChardness which represents an average hardness of themartensitic matrix and the carbides of the tool steel cannotbe the only guidance when designing hot forming tool steels

Conflicts of Interest

(e authors declare that they have no conflicts of interest

Acknowledgments

(e authors gratefully acknowledge the funding provided bythe Department of Research and Universities of the BasqueGovernment under Grant no IT947-16 and the University ofthe Basque Country UPVEHU under Program no UFI 1129

References

[1] O N Cora K Namiki and M Koc ldquoWear performance as-sessment of alternative stamping die materials utilizing a noveltest systemrdquo Wear vol 267 no 5ndash8 pp 1123ndash1129 2009

[2] J Hardell and B Prakash ldquoHigh-temperature friction andwear behaviour of different tool steels during sliding againstAlndashSi-coated high-strength steelrdquo Tribology Internationalvol 41 no 7 pp 663ndash671 2008

[3] J Hardell S Hernandez S Mozgovoy L PelcastreC Courbon and B Prakash ldquoEffect of oxide layers and nearsurface transformations on friction and wear during tool steeland boron steel interaction at high temperaturesrdquo Wearvol 330ndash331 pp 223ndash229 2015

[4] C Boher S Le Roux L Penazzi and C Dessain ldquoExperi-mental investigation of the tribological behavior and wearmechanisms of tool steel grades in hot stamping of a high-strength boron steelrdquo Wear vol 294-295 pp 286ndash295 2012

[5] A Ghiotti F Sgarabotto and S Bruschi ldquoA novel approach towear testing in hot stamping of high strength boron steelsheetsrdquo Wear vol 302 no 1-2 pp 1319ndash1326 2013

[6] L Deng SMozgovoy J Hardell B Prakash andMOldenburgldquoPress-hardening thermo- mechanical conditions in the contactbetween blank and toolrdquo in Proceedings of 4th InternationalConference on Hot Sheet Metal Forming of High-PerformanceSteel (CHS2) pp 293ndash300 Lulea Sweden June 2013

[7] A Ghiotti S Bruschi and F Borsetto ldquoTribological char-acteristics of high strength steel sheets under hot stampingconditionsrdquo Journal of Materials Processing Technologyvol 211 no 11 pp 1694ndash1700 2011

[8] G A Fontalvo and C Mitterer ldquo(e effect of oxide-formingalloying elements on the high temperature wear of a hot worksteelrdquo Wear vol 258 no 10 pp 1491ndash1499 2005

[9] L Pelcastre J Hardell and B Prakash ldquoGalling mechanismsduring interaction of tool steel and AlndashSi coated ultra-highstrength steel at elevated temperaturerdquo Tribology In-ternational vol 67 pp 263ndash271 2013

[10] K Dohda C Boher F Rezai-Aria and N MahayotsanunldquoTribology in metal forming at elevated temperaturesrdquoFriction vol 3 no 1 pp 1ndash27 2015

[11] G A Fontalvo R Humer C Mitterer K Sammt andI Schemmel ldquoMicrostructural aspects determining the ad-hesive wear of tool steelsrdquo Wear vol 260 no 9-10pp 1028ndash1034 2006

[12] I Hussainova E Hamed and I Jasiuk ldquoNanoindentationtesting and modeling of chromium-carbide-based compos-itesrdquo Mechanics of Composite Materials vol 46 no 6pp 667ndash678 2011

[13] Y Z Liu Y H Jiang J Feng and R Zhou ldquoElasticityelectronic properties and hardness of MoC investigated byfirst principles calculationsrdquo Physica B Condensed Mattervol 419 pp 45ndash50 2013

[14] L Wu T Yao Y Wang J Zhang F Xiao and B LiaoldquoUnderstanding the mechanical properties of vanadiumcarbides nano-indentation measurement and first-principlescalculationsrdquo Journal of Alloys and Compounds vol 548pp 60ndash64 2013

Table 5 Different carbides hardness

Nature of the carbide Hardness (GPa)Chromium carbides 102ndash20 [12]Molybdenum carbides 1339ndash2887 [13]Vanadium carbides 117ndash315 [14]

Advances in Materials Science and Engineering 11

CorrosionInternational Journal of

Hindawiwwwhindawicom Volume 2018

Advances in

Materials Science and EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Journal of

Chemistry

Analytical ChemistryInternational Journal of

Hindawiwwwhindawicom Volume 2018

ScienticaHindawiwwwhindawicom Volume 2018

Polymer ScienceInternational Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Advances in Condensed Matter Physics

Hindawiwwwhindawicom Volume 2018

International Journal of

BiomaterialsHindawiwwwhindawicom

Journal ofEngineeringVolume 2018

Applied ChemistryJournal of

Hindawiwwwhindawicom Volume 2018

NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Hindawiwwwhindawicom Volume 2018

High Energy PhysicsAdvances in

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

TribologyAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

ChemistryAdvances in

Hindawiwwwhindawicom Volume 2018

Advances inPhysical Chemistry

Hindawiwwwhindawicom Volume 2018

BioMed Research InternationalMaterials

Journal of

Hindawiwwwhindawicom Volume 2018

Na

nom

ate

ria

ls

Hindawiwwwhindawicom Volume 2018

Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

Full scale 3663 cts cursor ndash0021 (316 cts)0

CMnO

Fe

SWMoMo

Mo

VCr

Mn

Fe

Fe

1 2 3 4 5 6 7 8 9 10(keV)

Carbide steel 1Carbide steel 2Carbide steel 3

Figure 20 Comparison of the carbidesrsquo nature of the tool steels studied

20 μm

(a)

20 μm

(b)

20 μm

(c)

Figure 21 Detailed micrograph of steel 1 (a) steel 2 (b) and steel 3 (c)

10

ndash10

ndash20

ndash25 ndash20 ndash15 ndash10 ndash5 0 5 10

ndash30

ndash40

0

0 500 1000 1500 2000 2500 3000 3500

02000

40006000

8000

(a)

ndash5000

ndash4500

ndash4000

ndash3500

ndash3000

ndash2500

ndash2000

ndash1500

ndash1000

ndash500

000

500

1000

000 050 100 150 200 250 300x (mm)

350 400 450 500 550 600

ndashrms

Z (μ

m)

(b)

Figure 19 13ree-dimensional image of the disk track of steel 3 tested at 200degC (a) 13e maximum prole depth (32 microm) (b)

10 Advances in Materials Science and Engineering

wear rate of the disks at 200degC was higher than that at 40degCfor the steel 2 and steel 3 samples At this temperature steel 1and steel 2 showed similar behaviour while steel 3 per-formed worse

SEM inspections confirmed that oxide layer debriswhich is unstable at temperatures less than 300degC is releasedfrom the steel surface during the SRV test (ese releasedoxides are hard abrasive particles leading to severe three-body wear and the formation of depth grooves (is wearmechanism affected each tool steel with different levels ofseverity depending on the nature of the carbides in theirmicrostructure Steel 1 and steel 2 bearing vanadium andmolybdenum carbides whose hardness is larger than those ofthe chromium carbides in steel 3 had greater wear resistanceat 200degC

It must be remarked that even though steel 1 out-performed steel 3 in terms of wear resistance at 200degC itshows lower room temperature hardness (us the HRChardness which represents an average hardness of themartensitic matrix and the carbides of the tool steel cannotbe the only guidance when designing hot forming tool steels

Conflicts of Interest

(e authors declare that they have no conflicts of interest

Acknowledgments

(e authors gratefully acknowledge the funding provided bythe Department of Research and Universities of the BasqueGovernment under Grant no IT947-16 and the University ofthe Basque Country UPVEHU under Program no UFI 1129

References

[1] O N Cora K Namiki and M Koc ldquoWear performance as-sessment of alternative stamping die materials utilizing a noveltest systemrdquo Wear vol 267 no 5ndash8 pp 1123ndash1129 2009

[2] J Hardell and B Prakash ldquoHigh-temperature friction andwear behaviour of different tool steels during sliding againstAlndashSi-coated high-strength steelrdquo Tribology Internationalvol 41 no 7 pp 663ndash671 2008

[3] J Hardell S Hernandez S Mozgovoy L PelcastreC Courbon and B Prakash ldquoEffect of oxide layers and nearsurface transformations on friction and wear during tool steeland boron steel interaction at high temperaturesrdquo Wearvol 330ndash331 pp 223ndash229 2015

[4] C Boher S Le Roux L Penazzi and C Dessain ldquoExperi-mental investigation of the tribological behavior and wearmechanisms of tool steel grades in hot stamping of a high-strength boron steelrdquo Wear vol 294-295 pp 286ndash295 2012

[5] A Ghiotti F Sgarabotto and S Bruschi ldquoA novel approach towear testing in hot stamping of high strength boron steelsheetsrdquo Wear vol 302 no 1-2 pp 1319ndash1326 2013

[6] L Deng SMozgovoy J Hardell B Prakash andMOldenburgldquoPress-hardening thermo- mechanical conditions in the contactbetween blank and toolrdquo in Proceedings of 4th InternationalConference on Hot Sheet Metal Forming of High-PerformanceSteel (CHS2) pp 293ndash300 Lulea Sweden June 2013

[7] A Ghiotti S Bruschi and F Borsetto ldquoTribological char-acteristics of high strength steel sheets under hot stampingconditionsrdquo Journal of Materials Processing Technologyvol 211 no 11 pp 1694ndash1700 2011

[8] G A Fontalvo and C Mitterer ldquo(e effect of oxide-formingalloying elements on the high temperature wear of a hot worksteelrdquo Wear vol 258 no 10 pp 1491ndash1499 2005

[9] L Pelcastre J Hardell and B Prakash ldquoGalling mechanismsduring interaction of tool steel and AlndashSi coated ultra-highstrength steel at elevated temperaturerdquo Tribology In-ternational vol 67 pp 263ndash271 2013

[10] K Dohda C Boher F Rezai-Aria and N MahayotsanunldquoTribology in metal forming at elevated temperaturesrdquoFriction vol 3 no 1 pp 1ndash27 2015

[11] G A Fontalvo R Humer C Mitterer K Sammt andI Schemmel ldquoMicrostructural aspects determining the ad-hesive wear of tool steelsrdquo Wear vol 260 no 9-10pp 1028ndash1034 2006

[12] I Hussainova E Hamed and I Jasiuk ldquoNanoindentationtesting and modeling of chromium-carbide-based compos-itesrdquo Mechanics of Composite Materials vol 46 no 6pp 667ndash678 2011

[13] Y Z Liu Y H Jiang J Feng and R Zhou ldquoElasticityelectronic properties and hardness of MoC investigated byfirst principles calculationsrdquo Physica B Condensed Mattervol 419 pp 45ndash50 2013

[14] L Wu T Yao Y Wang J Zhang F Xiao and B LiaoldquoUnderstanding the mechanical properties of vanadiumcarbides nano-indentation measurement and first-principlescalculationsrdquo Journal of Alloys and Compounds vol 548pp 60ndash64 2013

Table 5 Different carbides hardness

Nature of the carbide Hardness (GPa)Chromium carbides 102ndash20 [12]Molybdenum carbides 1339ndash2887 [13]Vanadium carbides 117ndash315 [14]

Advances in Materials Science and Engineering 11

CorrosionInternational Journal of

Hindawiwwwhindawicom Volume 2018

Advances in

Materials Science and EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Journal of

Chemistry

Analytical ChemistryInternational Journal of

Hindawiwwwhindawicom Volume 2018

ScienticaHindawiwwwhindawicom Volume 2018

Polymer ScienceInternational Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Advances in Condensed Matter Physics

Hindawiwwwhindawicom Volume 2018

International Journal of

BiomaterialsHindawiwwwhindawicom

Journal ofEngineeringVolume 2018

Applied ChemistryJournal of

Hindawiwwwhindawicom Volume 2018

NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Hindawiwwwhindawicom Volume 2018

High Energy PhysicsAdvances in

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

TribologyAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

ChemistryAdvances in

Hindawiwwwhindawicom Volume 2018

Advances inPhysical Chemistry

Hindawiwwwhindawicom Volume 2018

BioMed Research InternationalMaterials

Journal of

Hindawiwwwhindawicom Volume 2018

Na

nom

ate

ria

ls

Hindawiwwwhindawicom Volume 2018

Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

wear rate of the disks at 200degC was higher than that at 40degCfor the steel 2 and steel 3 samples At this temperature steel 1and steel 2 showed similar behaviour while steel 3 per-formed worse

SEM inspections confirmed that oxide layer debriswhich is unstable at temperatures less than 300degC is releasedfrom the steel surface during the SRV test (ese releasedoxides are hard abrasive particles leading to severe three-body wear and the formation of depth grooves (is wearmechanism affected each tool steel with different levels ofseverity depending on the nature of the carbides in theirmicrostructure Steel 1 and steel 2 bearing vanadium andmolybdenum carbides whose hardness is larger than those ofthe chromium carbides in steel 3 had greater wear resistanceat 200degC

It must be remarked that even though steel 1 out-performed steel 3 in terms of wear resistance at 200degC itshows lower room temperature hardness (us the HRChardness which represents an average hardness of themartensitic matrix and the carbides of the tool steel cannotbe the only guidance when designing hot forming tool steels

Conflicts of Interest

(e authors declare that they have no conflicts of interest

Acknowledgments

(e authors gratefully acknowledge the funding provided bythe Department of Research and Universities of the BasqueGovernment under Grant no IT947-16 and the University ofthe Basque Country UPVEHU under Program no UFI 1129

References

[1] O N Cora K Namiki and M Koc ldquoWear performance as-sessment of alternative stamping die materials utilizing a noveltest systemrdquo Wear vol 267 no 5ndash8 pp 1123ndash1129 2009

[2] J Hardell and B Prakash ldquoHigh-temperature friction andwear behaviour of different tool steels during sliding againstAlndashSi-coated high-strength steelrdquo Tribology Internationalvol 41 no 7 pp 663ndash671 2008

[3] J Hardell S Hernandez S Mozgovoy L PelcastreC Courbon and B Prakash ldquoEffect of oxide layers and nearsurface transformations on friction and wear during tool steeland boron steel interaction at high temperaturesrdquo Wearvol 330ndash331 pp 223ndash229 2015

[4] C Boher S Le Roux L Penazzi and C Dessain ldquoExperi-mental investigation of the tribological behavior and wearmechanisms of tool steel grades in hot stamping of a high-strength boron steelrdquo Wear vol 294-295 pp 286ndash295 2012

[5] A Ghiotti F Sgarabotto and S Bruschi ldquoA novel approach towear testing in hot stamping of high strength boron steelsheetsrdquo Wear vol 302 no 1-2 pp 1319ndash1326 2013

[6] L Deng SMozgovoy J Hardell B Prakash andMOldenburgldquoPress-hardening thermo- mechanical conditions in the contactbetween blank and toolrdquo in Proceedings of 4th InternationalConference on Hot Sheet Metal Forming of High-PerformanceSteel (CHS2) pp 293ndash300 Lulea Sweden June 2013

[7] A Ghiotti S Bruschi and F Borsetto ldquoTribological char-acteristics of high strength steel sheets under hot stampingconditionsrdquo Journal of Materials Processing Technologyvol 211 no 11 pp 1694ndash1700 2011

[8] G A Fontalvo and C Mitterer ldquo(e effect of oxide-formingalloying elements on the high temperature wear of a hot worksteelrdquo Wear vol 258 no 10 pp 1491ndash1499 2005

[9] L Pelcastre J Hardell and B Prakash ldquoGalling mechanismsduring interaction of tool steel and AlndashSi coated ultra-highstrength steel at elevated temperaturerdquo Tribology In-ternational vol 67 pp 263ndash271 2013

[10] K Dohda C Boher F Rezai-Aria and N MahayotsanunldquoTribology in metal forming at elevated temperaturesrdquoFriction vol 3 no 1 pp 1ndash27 2015

[11] G A Fontalvo R Humer C Mitterer K Sammt andI Schemmel ldquoMicrostructural aspects determining the ad-hesive wear of tool steelsrdquo Wear vol 260 no 9-10pp 1028ndash1034 2006

[12] I Hussainova E Hamed and I Jasiuk ldquoNanoindentationtesting and modeling of chromium-carbide-based compos-itesrdquo Mechanics of Composite Materials vol 46 no 6pp 667ndash678 2011

[13] Y Z Liu Y H Jiang J Feng and R Zhou ldquoElasticityelectronic properties and hardness of MoC investigated byfirst principles calculationsrdquo Physica B Condensed Mattervol 419 pp 45ndash50 2013

[14] L Wu T Yao Y Wang J Zhang F Xiao and B LiaoldquoUnderstanding the mechanical properties of vanadiumcarbides nano-indentation measurement and first-principlescalculationsrdquo Journal of Alloys and Compounds vol 548pp 60ndash64 2013

Table 5 Different carbides hardness

Nature of the carbide Hardness (GPa)Chromium carbides 102ndash20 [12]Molybdenum carbides 1339ndash2887 [13]Vanadium carbides 117ndash315 [14]

Advances in Materials Science and Engineering 11

CorrosionInternational Journal of

Hindawiwwwhindawicom Volume 2018

Advances in

Materials Science and EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Journal of

Chemistry

Analytical ChemistryInternational Journal of

Hindawiwwwhindawicom Volume 2018

ScienticaHindawiwwwhindawicom Volume 2018

Polymer ScienceInternational Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Advances in Condensed Matter Physics

Hindawiwwwhindawicom Volume 2018

International Journal of

BiomaterialsHindawiwwwhindawicom

Journal ofEngineeringVolume 2018

Applied ChemistryJournal of

Hindawiwwwhindawicom Volume 2018

NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Hindawiwwwhindawicom Volume 2018

High Energy PhysicsAdvances in

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

TribologyAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

ChemistryAdvances in

Hindawiwwwhindawicom Volume 2018

Advances inPhysical Chemistry

Hindawiwwwhindawicom Volume 2018

BioMed Research InternationalMaterials

Journal of

Hindawiwwwhindawicom Volume 2018

Na

nom

ate

ria

ls

Hindawiwwwhindawicom Volume 2018

Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

CorrosionInternational Journal of

Hindawiwwwhindawicom Volume 2018

Advances in

Materials Science and EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Journal of

Chemistry

Analytical ChemistryInternational Journal of

Hindawiwwwhindawicom Volume 2018

ScienticaHindawiwwwhindawicom Volume 2018

Polymer ScienceInternational Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Advances in Condensed Matter Physics

Hindawiwwwhindawicom Volume 2018

International Journal of

BiomaterialsHindawiwwwhindawicom

Journal ofEngineeringVolume 2018

Applied ChemistryJournal of

Hindawiwwwhindawicom Volume 2018

NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Hindawiwwwhindawicom Volume 2018

High Energy PhysicsAdvances in

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

TribologyAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

ChemistryAdvances in

Hindawiwwwhindawicom Volume 2018

Advances inPhysical Chemistry

Hindawiwwwhindawicom Volume 2018

BioMed Research InternationalMaterials

Journal of

Hindawiwwwhindawicom Volume 2018

Na

nom

ate

ria

ls

Hindawiwwwhindawicom Volume 2018

Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom