High Performance Austenitic Stainless file4529 1.4529 N08926 0.01 0.20 20 25 6.5 Cu – 1.4529 – – 4565 1 ... 2 High Performance Austenitic Stainless Steel Mechanical properties

High PerformanceAustenitic Stainless Steel

Characteristic properties• Verygoodresistancetouniformcorrosion• Goodtoexceptionallygoodresistancetopittingand crevicecorrosion• Verygoodresistancetovarioustypesofstress corrosioncracking• Goodductility• Goodweldability

Applications• Processequipmentinchemicalindustry• Bleachingequipmentinthepulpandpaperindustry• Fluegascleaning• Desalination• Seawaterhandling• Hydrometallurgy• Foodandbeverage• Pharmaceuticals• Heatexchangers

Steel grades

Outokumpu EN ASTM

904L 1.4539 N08904254 SMO® 1.4547 S312544565 1.4565 S34565

Outokumpu International Chemical composition, % National steel designations, steel name steel No typical values superseded by EN

EN ASTM C N Cr Ni Mo Others BS DIN NF SS

4404 1.4404 316L 0.02 – 17 10 2.1 – 316S11 1.4404 Z3 CND 17-11-07 2348 4439 1.4439 S31726 0.02 0.14 18 13 4.1 – – 1.4439 Z3 CND 18-14-05 Az –904L 1.4539 N08904 0.01 – 20 25 4.3 1.5 Cu 904S13 1.4539 Z2 NCDU 25-20 2562254 SMO® 1.4547 S31254 0.01 0.20 20 18 6.1 Cu – – – 23784529 1.4529 N08926 0.01 0.20 20 25 6.5 Cu – 1.4529 – –4565 1.4565 S34565 0.02 0.45 24 17 4.5 5.5 Mn – 1.4565 – –

2205 1.4462 S32205* 0.02 0.17 22 5.7 3.1 – 318S13 1.4462 Z3 CND 22-05 Az 23772507 1.4410 S32750 0.02 0.27 25 7.0 4.0 – – – Z3 CND 25-06 Az 2328

* Also available as S31803

General characteristicsHighperformanceausteniticstainlesssteelsdiffersubstanti-allyfrommoreconventionalgradeswithregardtoresistancetocorrosionand,insomecases,alsomechanicalandphysicalproperties.Thisismainlyduetothehighcontentsofchro-mium,nickel,molybdenumandnitrogen.Highperformanceaustenticstainlesssteelshavegoodweldabilityandexcellentformability. Outokumpumanufacturesanumberofsteelsofthistype:904L,254SMO®and4565.Grade4529canalsobedelive-redifspecified.Thepropertiesof4529areingeneraltermsverysimilartothoseof254SMO®.

Chemical compositionThetypicalchemicalcompositionofOutokumpugradesareshownintable1.Thechemicalcompositionofaspecificsteelgrademayvaryslightlybetweendifferentnationalstan-dards.Therequiredstandardwillbefullymetasspecifiedontheorder.

Chemical composition Table 1

www.outokumpu.com

Dup

lex

Aus

teni

tic

2 High Performance Austenitic Stainless Steel

Mechanical propertiesThestrengthandelongationof904Laresimilartothoseforconventionalausteniticstainlesssteels.Theadditionofnitrogenin254SMO®and4565giveshigherproofstrengthandtensilestrength,seetables2and3.Despitethegreaterstrengthofthesesteels,thepossibilitiesforcoldaswellashotformingareverygood.

MicrostructureThehighperformanceausteniticstainlesssteelshaveafullyausteniticmicrostructureinthequenchannealedcondition.Theycan,however,containtracesofinterme-tallicphases(sigmaphase)atthecentreofthematerial.Normally,thisdoesnotaffectthecorrosionresistanceormechanicalpropertiesofthesteel.Providedthattherecom-mendationsgivenforhotforming,weldingandheattreat-mentarefollowed,suchprecipitateshavenegligibleeffectonusability.

904L 254 SMO® 4565 Rp0.2 Rp1.0 Rm Rp0.2 Rp1.0 Rm Rp0.2 Rp1.0 Rm

100°C 205 235 500 230 270 615 350 400 750200°C 175 205 460 190 225 560 270 310 640300°C 145 175 440 170 200 525 240 270 640400°C 125 155 – 160 190 510 210 240 610

904L 254 SMO® 4565

Density g/cm3 8.0 8.0 8.0Modulus of elasticity GPa 195 195 190Linear expansion at (20 100)°C x10-6/°C 15.8 16.5 14.5Thermal conductivity W/m°C 12 14 12Thermal capacity J/kg°C 450 500 450Electric resistivity µΩm 1.0 0.85 0.92

Tensile properties at elevated temperatures, minimum values according to EN, MPa Table 3

Typical values according to EN 10088 Table 4

Physical PropertiesIntable4typicalvaluesofsomephysicalpropertiesaregivenfor904L,254SMO®andthegrade4565.

Mechanical properties at 20˚C Table 2

Minimum values, Typical values according to EN 10088 P H C P (15mm) C(6 mm)

904L Proof strength Rp0.2 MPa 220 220 240 260Proof strength Rp1.0 MPa 260 260 270 300Tensile strength Rm MPa 520 530 530 600Elongation A5 % 35 35 35 50Hardness HB 155

254 SMO®

Proof strength Rp0.2 MPa 300 300 320 340 380Proof strength Rp1.0 MPa 340 340 350 380 420Tensile strength Rm MPa 650 650 650 680 730Elongation A5 % 40 35 35 50 45Hardness HB 160 184

4565Proof strength Rp0.2 MPa 420 420 420 440Proof strength Rp1.0 MPa 460 460 460 480Tensile strength Rm MPa 800 800 800 825Elongation A5 % 30 30 30 55Hardness HB 200

P = hot rolled plate. H = hot rolled strip. C = cold rolled coil and strip.

3High Performance Austenitic Stainless Steel

Temperature, °C100

80

60

40

200 1 2 3 4 5

HCI %

254 SMO®

904L

254 SMO®

904L

4404

Temperature, °C100

80

60

40

200 10 20 30

H2SO4 +2000 ppm Cl

Temperature, °C

100

80

60

40

20254 SMO®

904L

4404

4404

0 10 20 30 40 50 60 70 80 90 100

H2SO4 %

4404

4565

4565

Temperature, °C100

80

60

40

200 1 2 3 4 5

HCI %

254 SMO®

904L

254 SMO®

904L

4404

Temperature, °C100

80

60

40

200 10 20 30

H2SO4 +2000 ppm Cl

Temperature, °C

100

80

60

40

20254 SMO®

904L

4404

4404

0 10 20 30 40 50 60 70 80 90 100

H2SO4 %

4404

4565

4565

Fig. 2. Isocorrosion curves, 0.1 mm/year, in sulphuric acid containing 2000 ppm chloride.

Fig. 1. Isocorrosion curves, 0.1 mm/year, in pure sulp-huric acid.

Temperature, °C100

80

60

40

200 1 2 3 4

HF %

254 SMO®

904L

Temperature, °C100

80

60

40

200 5 10 15 20 25 30 35

H2SiF6 %

254 SMO®

904L4404

4404

Fig. 5. Isocorrosion curves, 0.1 mm/year, in pure fluosilicic acid.

Temperature, °C100

80

60

40

200 1 2 3 4

HF %

254 SMO®

904L

Temperature, °C100

80

60

40

200 5 10 15 20 25 30 35

H2SiF6 %

254 SMO®

904L4404

4404

Fig. 4. Isocorrosion curves, 0.1 mm/year, in pure hydrofluoric acid.

Temperature, °C100

80

60

40

200 1 2 3 4 5

HCI %

254 SMO®

904L

254 SMO®

904L

4404

Temperature, °C100

80

60

40

200 10 20 30

H2SO4 +2000 ppm Cl

Temperature, °C

100

80

60

40

20254 SMO®

904L

4404

4404

0 10 20 30 40 50 60 70 80 90 100

H2SO4 %

4404

4565

4565

Fig. 3. Isocorrosion curves, 0.1 mm/year, in pure hydrochloric acid.

Corrosion resistanceUniform corrosion

Thehighcontentofalloyingelementsgivesthesteels904L,254SMO®and4565exceptionallygoodresistancetouni-formcorrosion. 904Lwasoriginallydevelopedtowithstandenviron-mentsinvolvingdilutesulphuricacidanditisoneofthefewstainlesssteelsthatattemperaturesofupto35°Cpro-videsfullresistanceinsuchenvironmentswithintheentirerangeofconcentration,from0to100%,fig1.904Lalsooffersgoodresistancetoanumberofotherinorganicacids,e.g.,phosphoricacid,aswellasmostorganicacids. Acidsandacidsolutionscontaininghalideionscan,howe-ver,beveryaggressiveandthecorrosionresistanceof904Lmaybeinsufficient.Examplesofsuchacidsarehydrochloricacid,hydrofluoricacid,chloridecontaminatedsulphuricacid,phosphoricacidproducedaccordingtothewetprocess(WPA)atelevatedtemperatures,andalsopicklingacidbasedonnitricacidandhydrofluoricacidmixtures.Inthesecases254SMO®and4565arepreferableandincertaincasestheycanbeanalternativetootherconsiderablymoreexpensivealloys,Figures2-5andtables5and6.

Steel grade PRE

4404 254439 332205 35904L 352507 43254 SMO® 434565 46

ThePREvaluecanbeusedforroughcomparisonsofdif-ferentmaterials.Amuchmorereliablemeans,however,istorankthesteelaccordingtothecriticalpittingtemperatureofthematerial(CPT). ThereareseveraldifferentmethodsavailabletomeasuretheCPT.Figure6showstheCPT,asmeasuredintheAvestaCell(ASTMG150),ina1MNaClsolution(35,000ppmormg/lchlorideions).Theactualvalueofmillfinishsurfacemaydifferbetweenproductforms.


Bettermaterialmaysometimesbeneededforthefractionaldistillationoftalloilthanthe4404,oreventhemorefrequentlyused4439.Table7presentstheresultsofexposingtestcouponsataSwedishtalloilplantwiththeobjectofdeterminingsuitablematerialforwovenpackingsofstainlesssteel. Inthisparticularcase,packingsproducedfromabout20,000kmof0.16mmdiameter254SMO®wirewereused.

Inhotconcentratedcausticsolutionsthecorrosionresistanceismainlydeterminedbythenickelcontentofthematerial,and904Linparticularcanbeagoodalternativetomoreconventionalstainlesssteels. Formoredetailedinformationconcerningthecorrosionresistanceofthedifferentsteelsinotherenvironments,seeourCorrosionHandbook.

Pitting and Crevice corrosionResistancetopittingcorrosion(andalsocrevicecorrosion)isdeterminedmainlybythecontentofchromium,molyb-denumandnitrogeninthematerial.Thisisoftenillustratedusingthepittingresistanceequivalent(PRE)forthemate-rial,whichcanbecalculatedusingtheformula:PRE=%Cr+3.3x%Mo+16x%N.PREvaluesarepre-sentedintable8.

CPT, °C

4404 4436 2205 904L 2507 254 4565 SMO®

0

20

60

40

80

100

Fig. 6. Typical critical pitting corrosion temperatures (CPT) in 1M NaCl measured according to ASTM G150 using the Avesta Cell. Test Surfaces wet ground to 320 mesh. Values are presented with accuracy +/- 2oCor+/- 3oC.CPT varies with product form and surface finish.

Steel grade Corrosion rate, mm/year

4404 >5904L 0.51254 SMO® 0.31

Composition: 20% HNO3, 4% HF.

Uniform corrosion in pickling acid at 25°C Table 6

Corrosion rates in a fatty acid column for the

distillation of tall oil at 260°C Table 7

PRE values for different stainless steels Table 8


4404 0.884439 0.29904L 0.06254 SMO® 0.01

Composition: 54% P2O5, 0.06% HCl, 1.1% HF,4.0% H2SO4, 0.27% Fe2O3, 0.17% Al2O3, 0.10% SiO2, 0.20% CaO and 0.70% MgO

Uniform corrosion in wet process

phosphoric acid at 60°C Table 5


4404 >5904L 1.2254 SMO® 0.05

Grade4565hassuchagoodresistancetopittingthatcom-montestmethodsarenotsufficientlyaggressivetoinitiateanycorrosion.Abettermeasureofresistanceisgivenbyeva-luatingtheresultsofvariouscrevicecorrosiontests.


Innarrowcrevicesthepassivefilmmaymoreeasilybedamagedandinunfavourablecircumstancesstainlesssteelcanbesubjectedtocrevicecorrosion.Examplesofsuchnar-rowcrevicesmaybeundergasketsinflangefittings,undersealsincertaintypesofplateheatexchangers,orunderhardadherentdeposits. Crevicecorrosionoccursinthesameenvironmentsaspit-ting.Highercontentsofchromium,molybdenumornitro-genenhancethecorrosionresistanceofthesteel,seefig7.

Guide to Material Selection

Fig8illustratestowhichapproximatetemperaturesstainlesssteelcanbeusedinoxygensaturatedwatersofvaryingchlo-ridecontent.Itshouldbeunderlinedthattheresistanceofamaterialisalsoinfluencedbyfactorsotherthantemperatureandchloridecontent.Examplesofsuchfactorsarewelddefects,presenceofoxidefromwelding,contaminationofthesteelsurfacebyparticlesofnon-alloyedorlow-alloyedsteel,microbialactivity,pHandchlorinationofwater. Adeeperandmoreseverecreviceisformedbetweenthegasketandtheplateinplateheatexchangersduetothecurvedcontactsurface.Thereofthetwoboundarylinesforcrevicecorrosionon254SMO®infig.8. Itshould,however,benotedthatthecrevicegeometryofaflangejointisdependentonthepressurethatisobtainedwhentighteningscrewsandbolts.Theboundarylineforcrevicecorrosionunder“normal”conditionscaninpracticethereforebesimilartothatwhichappliestocrevicecorro-sionforplateheatexchangers.Alsothreadscontainequallyseverecrevices,whichshouldbeconsideredwhendesigningjointsinhighlyalloyedstainlesssteels.

CCT, C°

60

50

40

30

20

10

0

4404 4439 904L 2205

254 S

MO

®

2507

4565

Fig. 7. Typical critical crevice corrosion tem-perature (CCT) according to ASTM G48 Method F. Test surfaces dry ground to 120 mesh. CCT varies with product form and surface finish.

80

70

60

50

40

30

20

10 100 1000Cl- ppm

p=pitting, full line c=crevice corrosion, broken line

80

70

60

50

40

30

20

4307 p

4404 c

4307 c

4404 p

100 10000 100000Cl- ppm

p=pitting, full line c=crevice corrosion, broken line phe=plate heat exchanger

1000

904L c 254 SMO® c

4404 c

4404 p2205 c

2205 p

904L p

254 SMO® phe

254 SMO® p

Temperature, °C Temperature, °C

Fig. 8. Engineering diagram illustrating the risk of pitting and crevice corrosion on high

performance stainless steel in water of dif-ferent chloride content or temperature.


Increvice-free,weldedconstructions,254SMO®maynormallybeusedinchlorinatedseawaterwithachlorinecontentofupto1ppmattemperaturesuptoabout45°C.Higheralloyedmaterials,e.g.aNi-basealloy,shouldbeusedforflangejoints,orthesealingsurfacesshouldbeoverlaywelded,e.g.,usinganISONiCr25Mo16typefiller,ifthetemperatureexceeds30°C.Higherchlorinecontentcanbepermittedifchlorinationisintermittent. Theriskofcrevicecorrosioninnon-chlorinatedseawaterisconsiderablylower.254SMO®hassucessfullybeenusedinsomefiftyinstallationsfordesalinationofseawateraccor-dingtoreverseoSMO®sisprocess.

Applied stress, in % of Rp0.2 at 200 °C120

100

80

60

40

20

0

4404 2205 904L 2507 254 SMO®

<10

Fig. 9. Typical threshold stresses determined using the drop evaporation test.

Stress corrosion cracking

Conventionalstainlesssteelssuchas4307and4404aresen-sitivetostresscorrosioncracking(SCC)undercertaincondi-tions,i.e.aspecialenvironmentincombinationwithtensilestressinthematerialandoftenalsoanelevatedtemperature. ResistancetoSCCincreaseswiththeincreasedcontentofaboveallnickelandmolybdenum.Thisimpliesthatthehighperformanceausteniticsteels904L,254SMO®and4565haveverygoodresistancetoSCC. DifferentmethodsareusedtorankstainlesssteelgradeswithregardtotheirresistancetoSCC.Theresultscanvarydependingonthemethodandtestingenvironment.Theresistancetostresscorrosioncrackinginachloridesolutionunderevaporativeconditionscanbedeterminedaccordingtothedropevaporationmethod.Thismeansthatasaltsolutionisallowedtoslowlydripontoaheatedspecimen,whileitisbeingsubjectedtotensilestress.Bythismethodthethresholdvalueisdeterminedforthemaximumrelativestressnotresultinginruptureafter500hourstesting.Thethresholdvalueisusuallyexpressedasapercentageoftheproofstrengthofthesteelat200°C.Fig.9showstheresultsofsuchatest. Highperformanceausteniticsteelsandduplexsteelsofferconsiderablybetterresistancethan4404toSCC,fig.9.

Seawater

Naturalseawatercontainslivingorganisms,whichveryquicklyformabiofilmonstainlesssteel.Thisfilmincreasesthecorrosionpotentialofthesteelandthus,alsotheriskofpittingandcrevicecorrosion. Theactivityofthebiofilmistemperaturerelated.Thedifferentorganismsareadaptedtothenaturalwatertempe-ratureoftheirhabitat.Theiractivitythereforevariesbetweenthedifferentseasaroundtheworld.Thismeansthatincoldseasthenaturalwaterismostaggressiveat25-30°Cwhilethecorrespondingvalueintropicalseasisjustabove30°C.Thebiologicalactivityceasesathighertemperatures. Inmanyseawatersystemsthewaterischlorinatedwitheitherchlorineorhypochloritesolutionstoreducetheriskoffouling.Bothchlorineandhypochloritearestronglyoxi-disingagentsandtheycausethecorrosionpotentialofthesteelsurfacetoexceedwhatisnormalinnon-chlorinatedseawater,whichinturnmeansincreasedriskofcorrosion.Inchlorinatedseawatertheaggressivenessincreasesasthetem-peraturerises.


TheresistancetoalkalineSCCismoredependentonthenickelcontentofthematerialandalsointhisrespecthighperformanceausteniticsteelsaresuperiortoconventionalstainlesssteels.Nickel-basedalloysare,however,tobepre-ferredinthemostdemandingconditions.

Sulphide-induced stress corrosion cracking

Hydrogensulphidecansometimescauseembrittlementofferriticsteelandevenofcold-workedduplexandausteniticsteels.Thesensitivitytocrackingincreaseswhentheenvi-ronmentcontainsbothhydrogensulphideandchlorides.Such“sour”environmentsoccurforexampleintheoilandgasindustry.NACEMR0175/ISO15156-3providesrequirementsandrecommendationsforselectionofcorrosionresistantalloysforuseinoilandnaturalgasproductioninH2Senviron-ments.ItidentifiesmaterialsthatareresistanttocrackinginadefinedH2Scontainingenvironment,butdoesnotgua-ranteethatthematerialselectedusingthestandardwillbeimmunefromcrackingunderallserviceconditions.Austeniticsteels904L,254SMO®and4565areinclu-dedinNACEMR0175/ISO15156-3.InaccordancewithNACEMR0175/ISO15156-3solutionannealed904L,254SMO®and4565areacceptableforuseforanycomponentorequipmentupto60oCinsourenvironments,ifthepar-tialpressureofhydrogensulphide(pH2S)doesnotexceed1bar(15psi),orwithoutrestrictionontemperatureandpH2Sifthechlorideconcentrationdoesnotexceed50ppm.Further,solutionannealed254SMO®and4565areaccep-tableforuseupto171oCorpH2Supto7bar(100psi)ifthechlorideconcentrationdoesnotexceed5000ppm.

Intercrystalline corrosion

Highperformanceausteniticsteelshavesuchalowcarboncontentthattheriskofconventionalintercrystallinecorro-sioncausedbychromiumcarbideprecipitatesinconnectionwithweldingisnegligible. Thismeansthatweldingcanbeperformedwithoutriskofintercrystallinecorrosion.

Erosion corrosion

Unlikecopperalloys,stainlesssteelgenerallyoffersverygoodresistancetoimpingementattackandtherearenomotivesforlimitingthevelocityofwater,e.g.inpipingsystemsthatconveyseawater.Further,stainlesssteelisnotsensitivetoseawaterthathasbeencontaminatedbysulphurcompoundsorammonia. Insystemssubjectedtoparticlescausinghardwear,e.g.,sandorsaltcrystals,thehighersurfacehardnessofduplexsteelscaninsomecasesbeanadvantage.

Corrosion rate, mm/year1.0

0.8

0.6

0.4

0.2

0.01 2 3 4 5 10

Area ratio 254 SMO®/Metal

Muntzmetal

CuNi70/30

Monel

Al-bronze

Fig. 10. Galvanic cor ro sion of cop per alloys in slow moving sea wa ter at ambient tem pe ra ture.

Galvanic corrosion

Thehighperformanceausteniticsteels254SMO®and4565arenotaffectedbygalvaniccorrosioniftheyarecon-nectedtotitaniuminsystemsusedforconveyingseawater.However,therateofcorrosionforcopperalloysisincreasediftheycomeintocontactwithmoststainlesssteels(orwithtitanium).Theintensityofcorrosioniscloselyrelatedtothesurfacearearatiobetweenthestainlesssteelandthecopperalloy,fig10.Thetestspresentedhavebeencarriedoutwith254SMO®buttherelationisthesameforotherhighperfor-mancesteels. Thegalvaniceffectisreducedsomewhatiftheseawaterischlorinated.


FabricationHot forming

SuitabletemperaturesforhotformingareshowninTable9.Highertemperaturescauseadeteriorationinductilityandanincreaseintheformationofoxides(scaling)Normallyhotworkingshouldbefollowedbysolutionannealingandquenchingbut,for904L,ifthehotformingisdiscon-tinuedatatemperatureabove1100°Candthematerialisquencheddirectlythereafterthematerialmaybeusedwithoutsubsequentheattreatment.Itisimportantthattheentireworkpiecehasbeenquenchedfromtemperaturesabove1100°C.Inthecaseofpartialheatingorpartialcool-ingbelow1100°Corifthecoolinghasbeentooslow,hotworkingshouldalwaysbefollowedbysolutionannealingandquenching. Both254SMO®and4565shouldbequenchedatatemperatureofatleast1150°Cafterhotworkingtoavoidresidualintermetallicphases.Thesephasescanalsorebuildifthesubsequentcoolingprocessistooslow,resultinginimpairedcorrosionresistance.

Cold forming

Allthesesteelshavegoodductility.Bending,pressingandotherformingoperationscanbeperformedwithoutdif-ficulty. Thehighperformanceausteniticstainlesssteels,especially254SMO®and4565,cold-hardenconsiderablyfasterthanconventionalausteniticgrades.This,togetherwiththeini-tialhighstrength,makesitnecessarytoapplyhighformingforces.Thespringbackforgrades254SMO®and4565isalsogreaterthanforconventionalausteniticsteels. Typicalproofstrengthvalues,Rp0.2 ,aregiveninTable10.About90%ofrecordedvaluesfallwithinthelimitsshown. Spinningofe.g.dishedendscanbedonebutitisessen-

MPa1400

1200

1000

800

600

400

200

0 20 40 60Cold deformation, %

60

40

20

0

A5%

Rm Rp1.0

Rp0.2

A5

Fig. 12. 254 SMO® – influence of cold deforma-tion on the mechanical properties.

Fig. 11. 904L – influence of cold deformation on the mechanical properties.

800

700

600

500

400

300

200

100

0 5 10 15 20 25

Cold deformation, %

75

50

25

A5%

Rm

HB

Rp0.2

A5

MPa/HB

Steel grade 2 mm 5 mm 10 mm Rp0.2,MPa Rp0.2,MPa Rp0.2,MPa

904L 310 ± 30 290 ± 30 290 ± 20254 SMO® 390 ± 30 380 ± 30 4565 440 ± 30 440 ± 30 440 ± 20

Typical proof strength Table 10

904L 254 SMO® 4565

Hot forming 1200 - 950 1200 - 1000 1200 - 1000Solution annealing 1080 - 1160 1150 - 1200* 1120 - 1170

Pressure vessel approval (-60) - 400 (-60) - 400 (-196) - 400

* Quenching with water at a thickness above 2 mm, below 2 mm an annealing temperature of 1120-1150°C and cooling with air/water can be used.

Characteristic temperatures, °C Table 9

tialthatsufficientlyhighdeformationforcesareusedtoensurethoroughplasticdeformationofthematerialattheverybeginningoftheoperation.Otherwisethereisariskthatdeformationonlyoccursonthesurfaceandafterafewcyclesofdeformationitwillbecoldhardenedtosuchadegreethatthetensilestrengthandruptureelongationofthematerialareexceededwithsubsequentcracking. Incomplicatedcold-formingoperations,intermediate

annealingofthematerialmaysometimesbenecessary,espe-ciallyiftheworkpieceiswelded. Theeffectofworkhardening,duringandaftercold-forming,isillustratedinfig.11and12.


Machining

Austeniticstainlesssteelsworkhardenquicklyandthis,togetherwiththeirtoughness,meansthattheyareoftenperceivedasproblematicfromamachiningperspective,e.g.inoperationssuchasturning,millinganddrilling.Thisappliestoanevengreaterextenttomosthighlyalloyedsteelsandespeciallythosethathaveahighnitrogencontent,i.e.254SMO®and4565. However,withtherightchoiceoftools,toolsettingsandcuttingspeeds,thesematerialscanbesucessfullymachined.ForfurtherinformationcontactOutokumpu.

Welding

Allthesesteelsarewellsuitedforweldingandthemethodsusedforweldingconventionalausteniticsteelscanalsobeusedon904L,254SMO®and4565.However,duetotheirstableausteniticstructure,theyaresomewhatmoresensitivetohotcrackinginconnectionwithweldingandgenerallyweldingshouldbeperformedusingalowheatinput. Ondelivery,sheet,plateandotherprocessedproductshaveahomogeneousausteniticstructurewithanevendist-ributionofalloyingelementsinthematerial.Solidificationafterpartialremelting,e.g.bywelding,causesredistributionofcertainelementssuchasmolybdenum,chromiumandnickel.Thesevariations,segregation,remaininthecaststructureoftheweldandcanimpairthematerial’scorrosionresistanceincertainenvironments. Segregationtendencyislessevidentin904Landthissteelisnormallyweldedusingafillerofthesamecompositionasthebasematerialanditcanevenbeweldedwithoutfiller.For254SMO®and4565,however,thevariationformolyb-

* For use in certain oxidising environments, e.g. chlorine dioxide stage in pulp bleaching plants, when welding 254 SMO® or 4565.** For submerged arc welding it is preferable to use a Nb-free version, EN ISO NiCr22Mo9 or NiCr25Mo16.

denuminparticularissogreatthatitmustbecompensatedforbyusingfillers,whichhaveahighercontentofmolybde-num.ENISONiCr21MoFeNbtypefillerisnormallyusedforwelding254SMO®andISONiCr25Mo16typefillerisrecommendedfortheweldingof4565. Theeffectofsegregationafterweldingcanalsobereducedbysubsequentheattreatment,quenchannealing,butsuchactionisnormallylimitedtouncomplicatedgeometries,e.g.,pipes,pipefittingsandendpieces. Inthecaseofmulti-runwelding,theworkpieceshouldbeallowedtocoolto100°Cbeforeweldingthenextrun.Thisisthecaseforallthreesteels. Forfurtherinformationregardingjointselectionandpreparation,weldingtechniques,heatinputandpost-weldcleaning,pleasecontactOutokumpu.

Post Fabrication treatment

Inordertorestorethestainlesssteelsurfaceandachievegoodcorrosionresistanceafterfabrication,itisoftenneces-sarytoperformapostfabricationtreatment.Therearedifferentmethodsavailable,bothmechanicalmet-hodssuchasbrushing,blastingandgrindingandchemicalmethods,e.g.pickling.Whichmethodtoapplydependonwhatconsequencesthefabricationcaused,i.e.whattypeofimperfectionstoberemoved,butalsoonrequirementswithregardtocorrosionresistance,hygienicdemandsandaesthe-ticappearance.Formoreinformation,contactOutokumpu.

Product form Designation Typical composition, % C Si Mn Cr Ni Mo Others

Welding of 904L

Welding wire ISO 20 25 5 Cu L 0.01 0.35 1.7 20 25.5 4.5 1.5 CuCovered electrodes ISO 20 25 5 Cu N L 0.03 0.8 1.2 20.5 25 4.5 1.5 Cu

Welding of 254 SMO®

Welding wire ** EN ISO NiCr22Mo9Nb 0.01 0.1 0.1 22 65 9 3.6 Nb ISO NiCr25Mo16 0.01 0.1 0.2 25 60 15 -Covered electrodes EN ISO NiCr21MoFeNb 0.02 0.4 0.4 21.5 66 9.5 2.2Nb EN ISO NiCr23Mo16 0.02 0.2 0.3 25 59 15 -

Welding of 4565

Welding wire ISO NiCr25Mo16 0.01 0.1 0.2 25 60 15 - EN ISO NiCr20Mo15 0.015 0.1 1.0 20 64 15 -Covered electrodes ISO NiCr19Mo15 0.02 0.3 1.5 19 63 15 0.3 V EN ISO NiCr23Mo16 0.02 0.2 0.3 25 59 15 -

Welding of 254 SMO®* or 4565 *

Welding wire Avesta Welding P54 * 0.02 0.2 5.1 26 22 5.5 0.35 N

Welding consumables Table 11


Product

Hot rolled plate, sheet and strip

Cold rolled sheet and strip

Bars and forgins

Tube and Pipe

Pipe fittings

Wire rod and drawn wire

Castings

904L

Dimension according to Outokumpu product program





Fagersta Stainless

Foundries

254 SMO®






Fagersta Stainless

Licensed foundries

4565

Plate according to Outo-kumpu product program


see also www.outokumpu.com

Products

Outokumpu products Table 12


Material standards Table 13

EN 10028-7 Flat products for pressure purposes – Stainless steels

EN 10088-2 Stainless steels – Corrosion resisting sheet/plate/strip for general and construction purposes

EN 10088-3 Stainless steels – Corrosion resisting semi-finished products/bars/rods/wire/sections for general and construction purposes

EN 10088-4 Technical delivery conditions for sheet/plate and strip of corrosion resisting steels for construction purposes

EN 10088-5 Technical delivery conditiions for bars, rods, wire, sections and bright products of corrosion resistant steels for construction purposes

EN 10272 Stainless steel bars for pressure purposes

EN 10283 Corrosion resistant steel castings

ASTM A182 / ASME SA-182 Forged or rolled alloy-steel pipe flanges, forged fittings etc for high temperature service

ASTM A193 / ASME SA-193 Alloy and stainless steel bolts and nuts for high pressure and high temperature service

ASTM A240 / ASME SA-240 Heat-resisting Cr and Cr-Ni stainless steel plate/sheet/strip for pressure purposes

ASTM A249 / ASME SA-249 Welded austenitic steel boiler, superheater, heat exchanger and condenser tubes

ASTM A269 Seamless and welded austenitic stainless steel tubing for general service

ASTM A276 Stainless and heat-resisting steel bars/shapes

ASTM A312 / ASME SA-312 Seamless and welded austenitic stainless steel pipe

ASTM A351 / ASME SA-351 Steel castings, austenitic, duplex for pressure containing parts

ASTM A358 / ASME SA-358 Electric fusion-welded austenitic Cr-Ni alloy steel pipe for high temperature

ASME SA-403 Wrought austenitic stainless steel piping fitting

ASTM A409 / ASME SA-409 Welded large diameter austenitic pipe for corrosive or high-temperature service

ASTM A473 Stainless steel forgings for general use

ASTM A479 / ASME SA-479 Stainless steel bars for boilers and other pressure vessels

ASTM A743 Castings, Fe-Cr-Ni, corrosion resistant for general application

ASTM A744 Castings, Fe-Cr-Ni, corrosion resistant for severe service

NACE MR0175 Sulphide stress cracking resistant material for oil field equipment

ASTM B649 / ASME SB-649 Bar and wire

Norsok M-CR-630 Material data sheets for 6Mo stainless steel

VdTÜV WB 473 Austenitischer Walz- und Schmiedestahl. Blech, Band, Schmiedestück, Stabstahl für Druckbehälter

VdTÜV WB 537 Stickstofflegiertes austenitischen Stahl X2CrNiMnMoN 25-18-6-5 Werkstoff-Nr 1.4565

Information given in this brochure may be subject to alterations without notice. Care has been taken to ensure that the contents of this publication are accurate but Outokumpu and its affiliated companies do not accept responsibility for errors or for information which is found to be misleading. Suggestions for or descriptions of the end use or application of products or methods of working are for information only and Outokumpu and its affiliated companies accept no liability in respect thereof. Before using products supplied or manufactured by the company the customer should satisfy himself of their suitability.

1044EN

-GB

:5. Cen

trum

Tryck AB

, Avesta, S

wed

en. sep

2009.

www.outokumpu.com

Outokumpu Stainless AB, Avesta Research Centre

Box 74, SE-774 22 Avesta, Sweden

Tel. +46 (0)226 810 00, Fax +46 (0)226 810 77

Outokumpu is a global leader in stainless steel. Our vision is to be the undisputed number one in stainless, with success based on operational excellence. Customers in a wide range of industries use our stainless steel and services worldwide. Being fully recyclable, maintenance-free, as well as very strong and durable material, stainless steel is one of the key building blocks for sustainable future. What makes Outokumpu special is total customer focus - all the way, from R&D to delivery. You have the idea. We offer world-class stainless steel, technical know-how and support. We activate your ideas. (www.outokumpu.com)

Documents

High Performance Austenitic Stainless file4529 1.4529 N08926 0.01 0.20 20 25 6.5 Cu – 1.4529 – – 4565 1 ... 2 High Performance Austenitic Stainless Steel Mechanical properties