Towards comprehensive

control of wear

Kati Valtonen

Tampere University of Technology

Faculty of Engineering Sciences

Department of Materials Science

Tampere Wear Center

Fysikaalisen metallurgian hyödyntäminen terästä

käyttävässä teollisuudessa –seminaari

2. – 3.11.2016, POHTO, Oulu

2.11.2016 2

Tampere University of Technology

Collaborates

with approx. 230

universities

around the world

Quality assurance

system audited by

The Finnish Higher

Education

Evaluation Council

in 2014

Started operating

in the form of

a foundation

in 2010

Approx. 1,700

employees and

8,300 students(2015)

Established

in 1965

Department of Materials Science

• The only higher education unit

in Finland covering all material

groups

• Over 1000 M.Sc. (Eng.), 80

Lic.Tech., and 70 Ph.D. thesis

and more than 6000

publications since 1969

• High-level basic research of

the structure, properties,

processing, and use of

materials

• Researcher with knowledge of

and expertise in all groups of

materials

• Versatile and up-to-date

research and testing equipment

• Strong collaboration with

industry and academic units

Internationally high-level know-how

on ALL materials based on strong

interdisciplinary basic research

Tampere Wear Center

• Concentrates on both

scientific and practical

aspects of wear and

tribology

• Strengthens research in

the field of wear and

tribology of materials

• Special expertise areas

heavy abrasion, impact

wear, fretting and

tribology of machine

elements, such as gears,

bearings, brakes, seals,

and frictional joints

Tampere Wear Center - Research equipment

• Wear testing: Pin-on-disk/Ball-on-disk, Crushing pin-on-disk,

Uniaxial crusher, Dual pivoted jaw crusher, Impeller-tumbler,

Erosion tester, High-speed slurry-pot type erosion tester, Slurry

erosion-corrosion tester, Cavitation erosion tester, High velocity

particle impactor, Ball-on-block, Hammer mill, Single disc refiner,

Block-on-ring, Rubber wheel abrasion testers, etc.

• Tribology and machine elements test rigs: Test rigs for journal,

thrust, and rolling bearings, FZG, Twin-disc test rig, Fretting wear

and fatigue test rigs, Vibration Testing, etc.

• Microscopes (FEG-SEM, FIB-SEM, TEM, 3D profilometer, etc.)

• Hopkinson Split Bar systems

• Digital image correlation systems

• Mechanical testing

• Thermal spraying

• Other equipment at DMS

Scales of tribological testing

Helena Ronkainen: Friction and wear properties – tribotesting as a tool for performance evaluation, TWC International Seminar 2012

De

cre

ase

dco

st,

in

cre

ase

dco

ntr

ol

Incre

ase

dre

alis

m

Crushing Pin-on-disk

• Pin is repeatedly pressed against

the gravel bed and the disk with a

pneumatic cylinder (200-500N)

• Pin does not come into direct

contact with the disk at any time

wear of the components due to

abrasive ploughing and cutting on

the pin and disk surfaces

• During the test, the abrasive size

decreases at different rates,

depending on the pin-disk

combination.

• Simulates cone or jaw crusher

0.1

42

0.1

58

0.1

63

0.1

65

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72

0.1

73

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76

0.1

80

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86

0.1

89

0.1

92

0.1

99

0.2

02

0.2

08

0.2

16

0

100

200

300

400

500

600

700

800

900

1000

0.000

0.050

0.100

0.150

0.200

0.250

0 2 15 4 14 3 10 11 5 24 18 17 6 16 1

Su

rface

hard

nes

s [H

V5]

Mass

loss

[g]

Up to 50 % difference in abrasion wear

performance in similar 400HB steels

• 15 commercially available 400 HB steels were tested with crushing

pin-on-disk. Five steels were selected to closer study.

• The best wear performance was achieved by steels having good

orientation of the deformed surface layer

• The highest initial hardness and also highest local work hardening

did not result as best performance

Ojala, N. et al., Effects of composition and

microstructure on abrasive wear

performance of quenched wear resistant

steels, Wear 317(1–2): 225–232(2014).

B

E

EBA C D

Dual pivoted jaw crusher

• Laboratory scale jaw crusher for

studying the mechanisms of

abrasive wear during mineral

crushing

• Key design features:

– control of jaw movement without

changing the test geometry,

enabling accurate control of the

compression-sliding ratio

– versatile instrumentation for

monitoring the wear processes,

including piezoelectric force

sensors, high speed video

systems, etc.

• Test outcomes

– wear of both jaw specimen

– work in Fz and Fy directions

– feed size reduction to product

• Specimen

– jaw plate size 75*25*10 mm

– abrasive particle size 6-14 mm

Jaw1 Jaw2

Jaw1

Jaw2

Samples

Movement of jaws with 5°+5° jaw angles

0° frame setup

ΔY= 0.3 mm

ΔZ= 3.0 mm

45° frame setup

ΔY=3.23 mm

ΔZ=3.27 mm

90° frame setup

ΔY= 24.0 mm

ΔZ= 4.98 mm

Z

Y

Terva, J., et al. “Correlation of wear and work in dual pivoted jaw crusher tests”, Proceedings of Nordtrib 2016

(high speed video = 20 times slower)

High velocity particle impactor (HVPI)

• Developed for the model verification and to identify the basic mechanisms influencing the impact wear and failure behavior of materials

• Key design features:

– various angles and impact energies; projectile speed: 30…200 m/s

– suitable for various materials: metals, coatings, elastomers, hybrids, ...

– projectiles: metallic or ceramic ball bearing balls, cylinders, bullets, and rocks

– video recording: high speed camera NAC MEMRECAM up to 80 000 fps or LaVision StrainMaster 3D DIC systems (high and low rate)

– cooling setup: temperatures down to -80°C can be reached; cooling with nitrogen gas, impact happens in ambient air

Trap wall

Targetassembly

Speedmeasurement

device Smooth borePressurecontrol

Pressurizedair tank

Specimen

Cooling setup

Impacts recorded with high speed video

camera

Temperature -40°C

Sample angle 30°

Velocity ~78 m/s

Temperature -40°C

Sample angle 60°

Velocity ~112 m/s

Ratia, V., et al. “Impact behavior of

martensitic steel at low temperatures”,

Proceedings of Nordtrib 2016

Comparison of laboratory wear test results with

the in-service performance of cutting edges of

loader buckets

• The cutting edge of the underground mining loader bucket had been run 928

hours in an underground mine with quarry gravel.

– The dimensions of the cutting edge had been determined before and after the test:

27.1 percent of its weight, i.e. 335 kg was lost [Keltamäki & Ylitolva 2014].

– The wear rate had been highest on the underside of the bucket

– Material was 500 HB grade wear resistant steel

• In-service cutting edge was investigated and its

wear behavior was compared with laboratory

tested 400 HB and 500 HB grade steel samples

– Crushing pin-on-disc, uniaxial crusher, their

combination, impeller-tumbler, and high-speed

slurry-pot with dry abrasive bed (dry-pot)

Underside

Original

profile

Valtonen, K, et al. Proceedings of Nordtrib 2016

Crushing pin-on-disc (CPoD) Uniaxial crusher (UC)

Impeller-tumbler Slurry-pot with dry granite bed (dry-pot)

90 min test

(= 3 x 30 min)

1000 mm2 area

Cyclic loading

240 N force

2-10 mm granite

500 cycles

1000 mm2 area

53 kN force

4-6.3 mm granite

Combined test:

500 cycles UC +

30 min CPoD

360 min test

(= 24 x 15 min)

1200 mm2 area

700 rpm

8-10 mm granite

60 min test

(= 2 x 30 min)

2540 mm2 area

500 rpm

8-10 mm granite

Wear rates were highest in the dry-pot and

crushing pin-on-disc tests

• The wear rate decreased during

the crushing pin-on-disc tests

• Compared to the other methods,

the contact mechanism in the

impeller-tumbler is more impacting

than abrasive, which at least partly

explains the different results

• In the combined UC + CPoD tests,

the mass loss in the crushing pin-

on-disc test was 70% higher during

the first 10 minutes compared to

end of the test 0

50

100

150

200

250

300

350

400

450

500

0 10 20 30 40 50 60

Ma

ss

lo

ss

/no

min

al w

ea

r a

rea

[g

/m2

]Contact time [min]

Impeller-tumbler

Crushing pin-on-disc

Uniaxial crusher

Uniaxial crusher & crushing pin-on-disc

Dry-pot

500HB steel

Uniaxial crusher (UC)

Combined UC + CPoD

Dry-pot

White layers were formed in field,

uniaxial crusher, and dry-pot samples

• Microhardness of the white layers was up to 700

HV0.05 in underside of the field sample

• Thickness from few micrometers up to 130 µm and in

underside of the field sample even over 4 mm wide

– much thinner and smaller in laboratory tests

• In CPoD tests, delamination of white layers formed in

uniaxial crushing

• Adiabatic shear bands formed in impeller-tumbler tests

more impacting than abrasive

Underside of the cutting-edge sample

Cutting edge: underside upperside tip

Crushing pin-on-disc Uniaxial crusher Combined UC + CPoD

Impeller-tumbler

Crushing pin-on-disc

Dry-potCutting edge

Combined UC + CPoDUniaxial crusher

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

Crushing pod Uniaxial crusher Combined CPoD + UC Impeller-tumbler Dry-pot Cutting edge

Wea

r ra

te [

mm

/h]

400 HB 500 HB

Valtonen, K, et al. “Comparison of laboratory wear test results with the in-service

performance of cutting edges of loader buckets”, Proceedings of Nordtrib 2016

Conclusions

• The work hardening behavior of the studied steel could be simulated with all testing

methods used in this work.

– The hardened layers and the formed white layers appear to be thinner than in the in-service

conditions due to the lower applied forces.

• The dry-pot wear testing method with an abrasive gravel bed produced similar wear

rates and wear surfaces as the in-service operation.

– The abrasive type and size and the contact mechanisms were also quite similar when

compared to the in-service conditions.

• In the crushing pin-on-disc tests the wear type was also similar but the forces much

lower than in the in-service conditions.

• In the uniaxial crushing tests, the rock embedded in the sample in the similar manner

as in the tip of the cutting edge due to the high compression forces.

• In the impeller-tumbler tests, the impact effect is dominant.

• Proper simulation of the in-service conditions demands constant development

of the test methods and careful evaluation of the obtained results.

Metals Technology

• Metals and fabrication methods, heat treatments and joining

methods

• Materials science of metals; metallurgy and engineering properties

• New metallic materials; high entropy alloys

• Novel thin sheet steels; Quench & Partitioning (Q&P) alloys, Press

Hardening Boron Steels (PHS), Complex Phase (CP) Steels

• Forming of thin sheet; Deep drawing, Hole expansion of steel

• Heat treatments; case hardening, bake hardening, Q&P treatment

• Others: The long-term durability of metal-metal adhesive joints

Contact: Pasi Peura

AlCoCrCuFeNi -HEA

Press Hardening Boron Steels

• Development of process parameters, steel and protective coatings

• Laboratory press hardening equipment

• Basic steel 22MnB5

• Optimised galvannealed coating (ZF) for PHS

• The effect of the initial microstructure on the austenite grain size at

the end of austenisation is significant => It also effect the final

strength values

• Example Full hard vesus Batch annealed

– FH Vickers hardness HV482

– BA HV517

Järvinen et al. 2014 - 2016

22MnB5

Surface Engineering – research expertise

• Processing of advanced coatings by thermal spray, laser and

thin film processes

• Materials science of coatings and thin films - microstructure

and engineering properties

• Application-related properties and performance of

advanced surfaces and coatings

• Industrial applications of coatings and surface treatments

Thermal Spray Center Finland

• Strategic collaboration platform between Tampere University of Technology,

Department of Materials Science, and VTT Technical Research Centre of

Finland Ltd.

• Aim is to be at the leading edge of this research field thus creating a perfect

platform for international high-impact research and remarkable national

industrial influence.

• Modern and well-equipped thermal spray research laboratory with supporting

materials research laboratories of TUT and VTT.

Thermal spraying atPlasma spray equipment

• Sulzer Metco F4

• Saint Gobain ProPlasma

HVOF and HVAF spray equipment

• Sulzer Metco DJ-Standard (propane), DJ-1000 (propane),

DJ-2600 (hydrogen), DJ-2700 (propane, ethene) and Hybrid

DJ-2600 (hydrogen)

• GTV Top Gun (hydrogen, ethene)

• S-HVOF (suspension)

• Miller HV-2000 (hydrogen, ethene)

• Thermico HP-HVOF liquid fuel torch

• Kermetico propane/air system (HVAF)

• UniqueCoat M3TM (HVAF)

Flame spray equipment

• Sulzer Metco 6P-II and Castolin DS 8000 (powder)

• Sulzer Metco 12E (wire)

• Saint Gobain MasterJet (wire, rod, flexicord)

• TeroDyn polymer flame spray

Cold spray equipment

• High-pressure cold spray (Kinetiks 3000)

• Low-pressure cold spray (DYMET 403K)

• Laser-assisted cold spray

Arc spray equipment

• Sulzer Metco SmartArc and 6RC

HVOFHVAF

Thank you for your attention