Datasheetupdated2015021610:39:29(supersedesallpreviouseditions)

Sandvik 254 SMO(Tube and pipe, seamless)Sandvik254SMOisahighalloyausteniticstainlesssteeldevelopedforuseinseawaterandotheraggressivechloridebearingmedia.Thesteelischaracterizedbythefollowingproperties:

Excellent resistance to pitting and crevice corrosionHigh resistance to general corrosionHigh resistance to stress corrosion crackingHigher strength than conventional austenitic stainless steelsGood weldability

STANDARDS

UNS S31254EN number 1.4547EN name X1CrNiMoCuN20-18-7W.Nr. 1.4529**SS 2378*AFNOR Z1 CNDU 20.18.06AZ*

*Obsolete.ReplacedbyEN.**Nearestequivalentgrade.

Product standardsSeamless tube and pipe: ASTM A269, A213, A312, NFA 49-217, EN 10216-5Welded tube and pipe: ASTM A249, A269 , A312, A358, A409Fittings: ASTM A182Bar: ASTM A276, A479, EN 10088-3Forged products: ASTM A473

ApprovalsUNS S31254 (Sandvik 254 SMO) in the form of seamless pipe has been approved by theAmerican Society of Mechanical Engineers (ASME) for use according to ASME Boiler andPressure Vessel Code section VIII, div. 1. However, there is no approval for UNS S31254in the form of seamless tube, but according to the ASME paragraph UG-15 it is allowed touse the design values for seamless pipe according to ASME section VIII, div. 1 also forseamless tube.NACE MR 0175 (sulphide stress cracking resistant material for oil field equipment).

CHEMICAL COMPOSITION (NOMINAL) %

C Si Mn P S Cr Ni Mo N Cu

0.020 0.80 1.00 0.030 0.010 20 18 6.1 0.20 0 .7

FORMS OF SUPPLY

Seamlesstubeandpipearesuppliedindimensionsupto230mm(9.06in.)outsidediameter.Thedeliveryconditioniseithersolutionannealedandwhitepickled,orsolutionannealedinabrightannealingprocess.

Other forms of supplyWelded tube and pipeFittings and flangesBar steelForged productsCast products

MECHANICAL PROPERTIES

Thefollowingfiguresapplytosolutionannealedconditionseamlesstubeandpipe.

Wall thickness Proofstrength Tensilestrength Elong. Hardness

R R R A A HRB

mm MPa MPa MPa % %

METRIC UNITS, AT 20C

5 310 340 655850 35 35 961MPa=1N/mm

Wall thickness Proofstrength Tensilestrength Elong. Hardness

R R R A A HRB

inch ks i ks i ks i % %

IMPERIAL UNITS, AT 68F

0.187 45 49 98123 35 35 96a)R andR correspondto0.2%offsetand1.0%offsetyieldstrength,respectively.b)BasedonL =5.65S whereL istheoriginalgaugelengthandS theoriginalcrosssectionarea.

Impact strengthDuetoitsausteniticmicrostructure,Sandvik254SMOhasverygoodimpactstrengthbothatroomtemperatureandatcryogenictemperatures.

Testshavedemonstratedthatthesteelfulfilstherequirements(60J(44ftlb)at196 C(320 F))accordingtotheEuropeanstandardsEN134452(UFPV2)andEN102165.

At high temperaturesIntermetallicphasesareprecipitatedwithinthetemperaturerangeof6001000C(11101830F).Therefore,thesteelshouldnotbeexposedtothesetemperaturesforprolongedperiods.

Temperature Proofstrength

C R R

MPa MPa

min. min.

METRIC UNITS

100 230 270

200 190 225

300 170 200

400 160 190

500 148 180

p0 . 2a )

p 1 . 0a )

mb )

2 "

2

p0 . 2a )

p 1 . 0a )

mb )

2 "

p0.2 p1.00 0 0 0

oo

p0 . 2 p 1 . 0

Temperature Proofstrength

F R R

ks i ks i

min. min.

IMPERIAL UNITS

200 34 40

400 27 32

600 24 29

700 24 28

900 22 26

Figure1.Strengthvalues(min.values)forSandvik254SMOandallowablestressaccordingtoASMEBoilerandPressureVesselCodesectionVIII,div.1.

PHYSICAL PROPERTIES

Density:8.0g/cm ,0.29lb/in

Tempera tu re , C W /m C Tempera tu re , F Btu/f t h F

THERMAL CONDUCTIVITY

20 10 68 6

100 12 200 7

200 14 400 8

300 16 600 9.5

400 18 800 10.5

500 20 1000 11.5

600 21 1200 12.5

700 23 1300 13

p0 . 2 p 1 . 0

3 3

o o o o

Tempera ture , C J/kgC Temperature , F Btu/ft hF

SPECIFIC HEAT CAPACITY

20 485 68 0.12

100 510 200 0.12

200 535 400 0.13

300 565 600 0.14

400 585 800 0.14

500 600 1000 0.14

600 615 1200 0.15

700 625 1400 0.15

Tempera ture , C Per C Temperature , F PerF

THERMAL EXPANSION, MEAN VALUES IN TEMPERATURE RANGES (X10 )

30100 16 86200 9

30200 16 86400 9

30300 16.5 86600 9

30400 16.5 86800 9.5

30500 17 861000 9.5

30600 17 861200 9.5

30700 17.5 861300 10

Tempera ture , C MPa Temperature , F k s i

MODULUS OF ELASTICITY, (X10 )

20 195 68 28.3

100 190 200 27.6

200 182 400 27.5

300 174 600 25.1

400 166 800 23.8

500 158 1000 22.5

CORROSION RESISTANCE

Insolutionscontaininghalidessuchaschlorideandbromideions,conventionalstainlesssteelscanbereadilyattackedbylocalcorrosionintheformofpittingcorrosion,crevicecorrosionorstresscorrosioncracking(SCC).Inacidenvironments,thepresenceofhalidesalsoacceleratesgeneralcorrosion.

General corrosionInpuresulphuricacid,Sandvik254SMOismuchmoreresistantthanASTMTP316,andinnaturallyaeratedsulphuricacidcontainingchlorideionsSandvik254SMOexhibitshigherresistancethan'904L',seeFigure2.

6

3

Figure2.Isocorosiondiagram0.1mm/year(4mpy)innaturallyaeratedsulphuricacidcontaining2000ppmchlorideions.

Stress corrosion cracking (SCC)OrdinaryausteniticsteelsoftheASTMTP304andTP316typearepronetostresscorrosioncracking(SCC)inchloridecontainingsolutionsattemperaturesexceedingabout60C(140F).Fortheausteniticsteels,resistancetoSCCincreaseswithhighernickelandmolybdenumcontents.Thetablesbelowshowtheresultsoftwoacceleratedtests,clearlydemonstratingthatSandvik254SMOhasaverygoodresistancetoSCC.

Grade Timetofailure Remark

STRESS COROSION CRACKING TESTS IN BOILING 25% NACL SOLUTION, PH=1.5. U-BEND SPECIMENS.

ASTMTP316

Pitting corrosionItshighchromiumcontentandparticularlythemolybdenumcontentgiveSandvik254SMOexcellentresistancetopittingandcrevicecorrosion.Thehighnitrogencontentalsoimprovespittingresistance.

Theresultsoflaboratorydeterminationofthecriticalpittingtemperature(CPT)in3%NaClareshowninFigure3,whereitcanbeseenthatSandvik254SMOpossessesverygoodresistanceinwatercontainingchlorides.Sandvik254SMOis,therefore,asuitablematerialforuseinseawater.

Crevice corrosionTheweakpointofconventionalstainlesssteelsistheirlimitedresistancetocrevicecorrosion.Inseawater,forexample,thereisaconsiderablygreaterriskofcrevicecorrosionundergaskets,depositsorfouling.Testsinnaturalseawaterat60C(140F)haveshownthatSandvik254SMOcanbeexposedforprolongedperiodswithoutsufferingcrevicecorrosion.Figure4showstheresultsofacceleratedcrevicecorrosiontests.

Figure3.Criticalpittingtemperature(CPT)in3%NaCl,600mV/SCE.

Figure4.CriticalcrevicecorrosiontemperatureinFeClforSandvik254SMO,AISI316Land904L.AccordingtoASTMG48.

HEAT TREATMENT

Thetubesaredeliveredinheattreatedcondition.Ifadditionalheattreatmentisneededduetofurtherprocessingthefollowingisrecommended.

Solution annealing11501200C(21002190F),quenchinginwater.Thinwalledtubesmin.1130C(2060F),quenchinginair/water.

WELDING

TheweldabilityofSandvik254SMOisgood.Weldingshouldbeundertakenwithoutpreheating,andifcorrectlyperformedtherewillbenoneedforanysubsequentheattreatment.Suitablemethodsoffusionweldingaremanualmetalarcweldingwithcoveredelectrodesandgasshieldedarcwelding,mainlybymeansoftheTIGandMIGmethods.

Sincethematerialisintendedforuseunderseverecorrosiveconditions,weldingmustbecarriedoutwithcareandfollowedbythoroughcleaningtoensurethattheweldmetalandtheheataffectedzonemaintainthebestpossiblecorrosionproperties.

Theheatinputduringweldingshouldnotexceed1.5kJ/mm,andinmultipassweldingtheinterpasstemperatureshouldnotexceed100C(210F).Astringerbeadweldingtechniqueshouldbeused.

Theweldingoffullyausteniticsteelsusuallyentailsariskofhotcrackingintheweldmetal,particularlyiftheweldmentisunderconstraint.However,sinceSandvik254SMOhasaveryhighdegreeofpurity,theriskofthistypeofcrackingisgreatlyreduced.Backingbarsorsimilardevicesofcopperalloysmustnotbeusedsincecopperpenetrationintothegrainboundariesinstainlesssteelcanleadtocracking.

Incommonwithallausteniticstainlesssteels,Sandvik254SMOhaslowthermalconductivityandhighthermalexpansion.Forthisreason,weldingshouldbecarefullyplannedinadvancesothatdistortionoftheweldedjointcanbeminimized.If,despitetheseprecautions,itisbelievedthatresidualstressesmayimpairthefunctionoftheweldment,itisrecommendedthattheentirestructurebesolutionannealed.SeeunderHeattreatment.

Intheassuppliedcondition,thematerialhasahomogeneousstructure.Weldingwithoutfillermetalleadstostructuralchangesthatreducecorrosionresistance.Suchweldingshouldbefollowedbysolutionannealinginordertoensurethatthecorrosionpropertiesoftheweldmetalareequaltothoseoftheparentmetal.

WeldingwireSanicro60andcoveredelectrodesSanicro60arerecommendedasfillermetal.Thesefillermetalsareoveralloyedinordertocompensateformicrosegregationofmolybdenumandtherebyproducingaweldwithgoodcorrosionresistance.Dilutionfromparentmaterialintotheweldmetalshouldbekeptaslowaspossibletosecuregoodcorrosionresistance.Sanicro60isalsosuitableforweldingjointsbetweenSandvik254SMOandnickelalloys,otherstainlesssteelsorcarbonsteels.

FABRICATION

Avoidabrasionagainstcopper/copperalloysorothersimilarmetalswhich,ifpresentinmetallicform,cancausecracksduringsubsequentwelding,hotprocessingorheattreatment.

BendingTheexcellentformabilityofSandvik254SMOpermitscoldbendingtoverytightbendingradii.Annealingisnotnormallynecessaryaftercoldbending.

MachiningSandvik254SMOisahighalloyedausteniticstainlesssteelandthustougherinsertsinmetalcuttingareneededthanisthecaseforloweralloyedausteniticgrades.WhenmachiningSandvik254SMOconsiderablylowercuttingspeedsarerecommendedcomparedtothegradesSanmac304/304LandSanmac316/316L,whichhaveimprovedmachinability.

APPLICATIONS

Sandvik254SMOisusedinthefollowingapplications:

Equipment for handling of seawater, such as, seawater cooling, cooling water pipes,ballast water systems, firefighting systems etc.Hydraulic and instrumention tubingEquipment in pulp bleaching plantsComponents in gas cleaning systemsTanks and pipelines for chemicals with high halide contents

Trademarkinformation:254SMOisatrademarkownedbyOutokumpuOY.

DISCLAIMER:Recommendationsareforguidanceonly,andthesuitabilityofamaterialforaspecificapplicationcanbeconfirmedonlywhenweknowtheactualserviceconditions.Continuousdevelopmentmaynecessitatechangesintechnicaldatawithoutnotice.ThisdatasheetisonlyvalidforSandvikmaterials.

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