Alloy 316-300系列不銹鋼性能

/Chinese/309-309S.html300不銹鋼板材Alloy316/316L

SandmeyerSteelCompanystocksthelargestsingle-sitestainlesssteelplateinventoryinNorthAmericawiththicknessesfrom3/16"through6-1/2"in1/8"increments.Alloy316/361L316合金(UNSS31600)和316L(UNSS31603)是以鉬為基礎的奧氏體不銹鋼，這個不銹鋼與常規(guī)的鉻-鎳奧氏體如304合金相比，具有更好的抗一般腐蝕及斑蝕、裂隙腐蝕的能力。這些合金具有更高的延展性、抗應力腐蝕性能、耐壓強度及耐高溫性能。除了出色的抗腐蝕能力及強度，316合金和316L銅-鎳-鉬合金還具有奧氏體不銹鋼的典型特征即良好的裝配性及成形性。Specs:316(UNSS31600),316L(S31603)

GeneralProperties

Composition

ResistancetoCorrosion

OxidationResistance

PhysicalProperties

MechanicalProperties

HeatTreatment

Fabrication

GeneralProperties

Alloys316(UNSS31600),316L(S31603),and317L(S31703)aremolybdenum-bearingausteniticstainlesssteelswhicharemoreresistanttogeneralcorrosionandpitting/crevicecorrosionthantheconventionalchromium-nickelausteniticstainlesssteelssuchasAlloy304.Thesealloysalsoofferhighercreep,stress-to-rupture,andtensilestrengthatelevatedtemperature.Alloy317Lcontaining3to4%molybdenumispreferredtoAlloys316or316Lwhichcontain2to3%molybdenuminapplicationsrequiringenhancedpittingandgeneralcorrosionresistance.Inadditiontoexcellentcorrosionresistanceandstrengthproperties,theAlloys316,316L,and317LCr-Ni-Moalloysalsoprovidetheexcellentfabricabilityandformabilitywhicharetypicaloftheausteniticstainlesssteels.BacktotopComposition

ChemicalcompositionasrepresentedbyASTMA240andASMESA-240specificationsareindicatedinthetablebelow.

PercentagebyWeight

(maximumunlessrangeisspecified)ElementAlloy316Alloy316LAlloy317LCarbon0.080.0300.030Manganese2.002.002.00Silicon0.750.750.75Chromium16.00

18.0016.00

18.0018.00

20.00Nickel10.00

14.0010.00

14.0011.00

15.00Molybdenum2.00

3.002.00

3.003.00

4.00Phosphorus0.0450.0450.045Sulfur0.0300.0300.030Nitrogen0IronBalanceBalanceBalanceBacktotopResistancetoCorrosion

GeneralCorrosion

Alloys316,316L,and317Laremoreresistanttoatmosphericandothermildtypesofcorrosionthanthe18-8stainlesssteels.Ingeneral,mediathatdonotcorrode18-8stainlesssteelswillnotattackthesemolybdenum-containinggrades.Oneknownexceptionishighlyoxidizingacidssuchasnitricacidtowhichthemolybdenum-bearingstainlesssteelsarelessresistantAlloys316and317Lareconsiderablymoreresistantthananyoftheotherchromium-nickeltypestosolutionsofsulfuricacid.Attemperaturesashighas120°F(38°C),bothtypeshaveexcellentresistancetohigherconcentrations.Servicetestsareusuallydesirableasoperatingconditionsandacidcontaminantsmaysignificantlyaffectcorrosionrate.Wherecondensationofsulfur-bearinggasesoccurs,thesealloysaremuchmoreresistantthanothertypesofstainlesssteels.Insuchapplications,however,theacidconcentrationhasamarkedinfluenceontherateofattackandshouldbecarefullydetermined.Themolybdenum-bearingAlloys316and317Lstainlesssteelsalsoprovideresistancetoawidevarietyofotherenvironments.Asshownbythelaboratorycorrosiondatabelow,thesealloysofferexcellentresistancetoboiling20%phosphoricacid.Theyarealsowidelyusedinhandlinghotorganicandfattyacids.Thisisafactorinthemanufactureandhandlingofcertainfoodandpharmaceuticalproductswherethemolybdenum-containingstainlesssteelsareoftenrequiredinordertominimizemetalliccontamination.Generally,theAlloy316and316Lgradescanbeconsideredtoperformequallywellforagivenenvironment.ThesameistrueforAlloy317L.Anotableexceptionisinenvironmentssufficientlycorrosivetocauseintergranularcorrosionofweldsandheat-affectedzonesonsusceptiblealloys.Insuchmedia,theAlloy316Land317Lgradesarepreferredfortheweldedconditionsincelowcarbonlevelsenhanceresistancetointergranularcorrosion.CorrosionResistanceinBoilingSolutionsBoilingTest

SolutionCorrosionRateinMilsperYear(mm/y)forCitedAlloysAlloy316LAlloy317LBase

MetalWeldedBase

MetalWelded20%

AceticAcid0.12

(0.003)0.12

(0.003)0.48

(0.012)0.36

(0.009)45%

FormicAcid23.4

(0.594)20.9

(0.531)18.3

(0.465)24.2

(0.615)1%

HydrochloricAcid0.96

(0.024)63.6

(1.615)54.2

(1.377)51.4

(1.306)10%

OxalicAcid48.2

(1.224)44.5

(1.130)44.9

(1.140)43.1

(1.094)20%

PhosphoricAcid0.60

(0.15)1.08

(0.027)0.72

(0.018)0.60

(0.015)10%

SulfamicAcid124.2

(3.155)119.3

(3.030)94.2

(2.393)97.9

(2.487)10%

SulfuricAcid635.3

(16.137)658.2

(16.718)298.1

(7.571)356.4

(9.053)10%

SodiumBisulfate71.5

(1.816)56.2

(1.427)55.9

(1.420)66.4

(1.687)50%

SodiumHydroxide77.6

(1.971)85.4

(2.169)32.8

(0.833)31.9

(0.810)Pitting/CreviceCorrosion

Resistanceofausteniticstainlesssteelstopittingand/orcrevicecorrosioninthepresenceofchlorideorotherhalideionsisenhancedbyhigherchromium(Cr),molybdenum(Mo),andnitrogen(N)content.ArelativemeasureofpittingresistanceisgivenbythePREN(PittingResistanceEquivalent,includingNitrogen)calculation,wherePRE=Cr+3.3Mo+16N.ThePRENofAlloys316and316L(24.2)isbetterthanthatofAlloy304(PREN=19.0),reflectingthebetterpittingresistancewhich316(or316L)offersduetoitsMocontent.Alloy317L,with31.%MoandPREN=29.7,offersevenbetterresistancetopittingthanthe316alloys.Alloy304stainlesssteelisconsideredtoresistpittingandcrevicecorrosioninwaterscontaininguptoabout100ppmchloride.TheMo-bearingAlloy316andAlloy317Lontheotherhandwillhandlewaterswithuptoabout2000and5000ppmchloride,respectively.Althoughthesealloyshavebeenusedwithmixedsuccessinseawater(19,000ppmchloride),theyarenotrecommendedforsuchuse.Alloy2507with4%Mo,25%Cr,and7%Niisdesignedforuseinsaltwater.TheAlloys316and317Lareconsideredtobeadequateforsomemarineenvironmentapplicationssuchasboatrailsandhardwareandfacadesofbuildingsneartheocean,whichareexposedtosaltspray.TheAlloys316and317Lstainlesssteelsallperformwithoutevidenceofcorrosioninthe100-hour,5%saltspray(ASTMB117)test.IntergranularCorrosion

BothAlloys316and317Laresusceptibletoprecipitationofchromiumcarbidesingrainboundarieswhenexposedtotemperaturesinthe800to1500°F(427to816°C)range.Such"sensitized"steelsaresubjecttointergranularcorrosionwhenexposedtoaggressiveenvironments.Whereshortperiodsofexposureareencountered,however,suchasinwelding,Alloy317Lwithitshigherchromiumandmolybdenumcontent,ismoreresistanttointergranularattackthanAlloy316forapplicationswherelightgaugematerialistobewelded.Heaviercrosssectionsover7/16inch(11.1mm)usuallyrequireannealingevenwhenAlloy317Lisused.Forapplicationswhereheavycrosssectionscannotbeannealedafterweldingorwherelowtemperaturestressrelievingtreatmentsaredesired,thelowcarbonAlloys316Land317Lareavailabletoavoidthehazardofintergranularcorrosion.Thisprovidesresistancetointergranularattackwithanythicknessintheas-weldedconditionorwithshortperiodsofexposureinthe800to1500°F(427to826°C)temperaturerange.Wherevesselsrequirestress-relievingtreatment,shorttreatmentsfallingwithintheselimitscanbeemployedwithoutaffectingthenormalexcellentcorrosionresistanceofthemetal.Acceleratedcoolingfromhighertemperaturesforthe"L"gradesisnotneededwhenveryheavyorbulkysectionshavebeenannealed.Alloys316Land317Lpossessthesamedesirablecorrosionresistanceandmechanicalpropertiesasthecorrespondinghighercarbonalloysandofferanadditionaladvantageinhighlycorrosiveapplicationswhereintergranularcorrosionisahazard.Althoughtheshortdurationheatingencounteredduringweldingorstressrelievingdoesnotproducesusceptibilitytointergranularcorrosion,itshouldbenotedthatcontinuousorprolongedexposureat800to1500°F(427to826°C)canbeharmfulfromthisstandpointwithAlloys316Land317L.Alsostressrelievingbetween1100to1500°F(593to816°C)maycausesomeslightembrittlementofthesetypes.IntergranularCorrosionTestsASTMA262Evaluation

TestCorrosionRate,Mils/Yr(mm/a)Alloy316Alloy316LAlloy317LPracticeB

BaseMetal

Welded

36(0.9)

41(1.0)

26(0.7)

23(0.6)

21(0.5)

24(0.6)PracticeE

BaseMetal

Welded

NoFissures

onBend

SomeFissures

onWeld(unacceptable)

NoFissures

NoFissures

NoFissures

NoFissuresPracticeA

BaseMetal

Welded

StepStructure

Ditched(unacceptable)

StepStructure

StepStructure

StepStructure

StepStructureStressCorrosionCracking

Austeniticstainlesssteelsaresusceptibletostresscorrosioncracking(SCC)inhalideenvironments.AlthoughtheAlloys316and317LaresomewhatmoreresistanttoSCCthanthe18Cr-8Nialloysbecauseoftheirmolybdenumcontent,theystillarequiresusceptible.ConditionswhichproduceSSCare:(1)presenceofhalideion(generallychloride),(2)residualtensilestresses,and(3)temperaturesinexcessofabout120°F(49°C).Stressesresultfromcolddeformationorthermalcyclesduringwelding.Annealingorstressrelievingheattreatmentsmaybeeffectiveinreducingstresses,therebyreducingsensitivitytohalideSCC.Althoughthelowcarbon"L"gradesoffernoadvantageasregardsSCCresistance,theyarebetterchoicesforserviceinthestress-relievedconditioninenvironmentswhichmightcauseintergranularcorrosion.Halide(Chloride)StressCorrosionTestsTestU-Bend(HighlyStressed)SamplesAlloy316Alloy316LAlloy317L42%MagnesiumChloride,BoilingCracked,

4-24hoursCracked,

21-45hoursCracked,

72hours33%LithiumChloride,BoilingCracked,

48-569hoursCracked,

21-333hoursCracked,

22-72hours26%SodiumChloride,BoilingCracked,

530-940hoursNoCracking,

1002hoursCracked,

1000hours40%CalciumChloride,BoilingCracked,

144-1000hours----SeacoastExposure,AmbientTemperatureNoCrackingNoCrackingNoCrackingBacktotopOxidationResistance

TheAlloys316and317Lexhibitexcellentresistancetooxidationandalowrateofscalinginairatmospheresattemperaturesupto1600to1650°F(871to899°C).TheperformanceofAlloy316isgenerallysomewhatinferiortothatofAlloy304stainlesssteelwhichhasslightlyhigherchromiumcontent(18%vs.16%forAlloy316).Sincetherateofoxidationisgreatlyinfluencedbytheatmosphereencounteredandbyoperatingconditions,noactualdatacanbepresentedwhichareapplicabletoallserviceconditions.BacktotopPhysicalProperties

Structure

Whenproperlyannealed,Alloys316and317Lareprimarilyaustenitic.Smallquantitiesofferritemayormaynotbepresent.Whenslowlycooledorheldinthetemperaturerange800to1500°F(427to816°C),carbidesareprecipitatedandthestructureconsistsofaustenitepluscarbides.MeltingRange:2450to2630°F(1390to1440°C)Density:0.29lb/in3(8.027g/cm3)ModulusofElasticityinTension:29x106psi(200Gpa)ModulusofShear:11.9x106psi(82Gpa)CoefficientofLinearThermalExpansionTemperatureRangeCoefficients°F°Cin/in/°Fcm/cm/°C68-21220-1009.2x10-616.5x10-668-93220-50010.1x10-618.2x10-668-183220-100010.8x10-619.5x10-6ThermalConductivityTemperatureRangeBtu?in/hr?ft2?°FW/m?K°F°C68-21220-100100.814.6Theoverallheattransfercoefficientofmetalsisdeterminedbyfactorsinadditiontothermalconductivityofthemetal.Theabilityofthe18-8stainlessgradestomaintaincleansurfacesoftenallowsbetterheattransferthanothermetalshavinghigherthermalconductivity.SpecificHeat°F°CBtu/lb?°FJkg?K68200.108450200930.116485ElectricalResistivityAlloyValueat68°F(20°C)Microhm-in.Microhm-cm.31629.174.031731.179.0MagneticPermeability

Austeniticstainlesssteelsarenon-magneticintheannealed,fullyausteniticcondition.ThemagneticpermeabilityoftheAlloys316and317Lintheannealedconditionisgenerallylessthan1.02at200H(oersteds).Permeabilityvaluesforcolddeformedmaterialvarywithcompositionandtheamountofcolddeformationbutareusuallyhigherthanthatforannealedmaterial.BacktotopMechanicalProperties

RoomTemperatureTensileProperties

MinimummechanicalpropertiesforannealedAlloys316,316Land317LausteniticstainlesssteelplateasrequiredbyASTMspecificationsA240andASMEspecificationSA-240areshownbelow.PropertyMinimumMechanicalPropertiesRequiredbyASTMA240andASMESA-240Alloy316(S31600)Alloy316L(S31603)Alloy317L(S31703)YieldStrength

0.2%Offset

psi(MPa)30,000

(205)25,000

(170)30,000

(205)UltimateTensileStrength

psi(MPa)75,000

(515)70,000

(485)75,000

(515)PercentElongationin2in.or51mm.40.040.040.0HardnessMax.

Brinell(RB)217

(95)217

(95)217

(95)EffectofColdWork

Deformationofausteniticalloysatroomorslightlyelevatedtemperatureproducesanincreaseinstrengthaccompaniedbyadecreaseinelongationvalue.Alloys316,316L,and317Lflatrolledproductsaregenerallyavailableintheannealedcondition.AnalysesTested(Seefootnote)AlloyCMnCrNiMo3160.0511.6517.3313.792.02316L0.0151.8416.1710.162.11317L0.0251.7218.4812.753.15ElevatedTemperatureTensileProperties

RepresentativeshorttimeelevatedtemperaturetensilepropertiesforAlloys316,316L,and317Lofthefollowinganalysesareshownbelow.AnalysesTested(Seefootnote)AlloyCMnCrNiMo3160.0801.517.7812.52.46316L0.0151.8416.1710.162.11317L0.0251.7218.4812.753.15Type316(Barspecimentensiontestprocedures)TestTemperatureYieldStrength

0.2%OffsetUltimateTensile

Strength°F°CpsiMPapsiMPa682042,00029282,00056820093----75,600521400204----71,400492600316----71,15049180042726,50018371,450493100053823,40016168,400472120064922,60015650,6503491400760----30,7002121600871----18,000124TestTemperatureElongation,Percentin

2in.(51mm)Reduction

inArea,Percent°F°C682068.081.02009354.080.040020451.078.060031648.071.080042747.071.0100053855.070.0120064924.032.0140076026.035.0160087147.040.0StressRuptureandCreepProperties

Attemperaturesofabout1000°F(538°C)andhigher,creepandstressrupturebecomeconsiderationsfortheausteniticstainlesssteels.Considerablevariationinthecreepstrengthandstressrupturestrengthvaluesisreportedbyvariousinvestigators.ImpactResistance

Theannealedausteniticstainlesssteelsmaintainahighlevelofimpactresistanceevenatcryogenictemperatures,apropertywhich,incombinationwiththeirlowtemperaturestrengthandfabricability,hasledtotheirextensiveuseincryogenicapplications.RepresentativeCharpyV-notchimpactdataforannealedType316atroomtemperatureareshownbelow.TemperatureEnergyAbsorbed°F°CFt-lbJ752365-10088-134FatigueStrength

Thefatiguestrengthorendurancelimitisthemaximumstressbelowwhichmaterialisunlikelytofailin10millioncyclesinairenvironment.Forausteniticstainlesssteelsasagroup,thefatiguestrengthistypicallyabout35percentofthetensilestrength.Substantialvariabilityinserviceresultsisexperiencedsinceadditionalvariablessuchascorrosiveconditions,formofstressandmeanvalue,surfaceroughness,andotherfactorsaffectfatigueproperties.Forthisreason,nodefinitiveendurancelimitvaluescanbegivenwhicharerepresentativeofalloperatingconditions.BacktotopHeatTreatment

Annealing

Theausteniticstainlesssteelsareprovidedinthemillannealedconditionreadyforuse.Heattreatmentmaybenecessaryduringorafterfabricationtoremovetheeffectsofcoldformingortodissolveprecipitatedchromiumcarbidesresultingfromthermalexposures.FortheAlloys316and317Lthesolutionannealisaccomplishedbyheatinginthe1900to2150°F(1040to1175°C)temperaturerangefollowedbyaircoolingorawaterquench,dependingonsectionthickness.Coolingshouldbesufficientlyrapidthroughthe1500to800°F(816to427°C)rangetoavoidreprecipitationofchromiumcarbidesandprovideoptimumcorrosionresistance.Ineverycase,themetalshouldbecooledfromtheannealingtemperaturetoblackheatinlessthanthreeminutes.Alloys316and317Lcannotbehardenedbyheattreatment.ForgingInitial2100-2200°F(1150-1205°C)Finishing1700-1750°F(927-955°C)BacktotopFabrication

Theausteniticstainlesssteels,includingtheAlloys316and317L,areroutinelyfabricatedintoavarietyofshapesrangingfromtheverysimpletoverycomplex.Thesealloysareblanked,pierced,andformedonequipmentessentiallythesameasusedforcarbonsteel.Theexcellentductilityoftheausteniticalloysallowsthemtobereadilyformedbybending,stretching,deepdrawing,andspinning.However,becauseoftheirgreaterstrengthandworkhardenability,thepowerrequirementsfortheausteniticgradesduringformingoperationsareconsiderablygreaterthanforcarbonsteels.Attentiontolubricationduringformingoftheausteniticalloysisessentialtoaccommodatethehighstrengthandgallingtendencyofthesealloys.Welding

Theausteniticstainlesssteelsareconsideredtobethemostweldableofthestainlesssteels.Theyareroutinelyjoinedbyallfusionandresistanceweldingprocesses.Twoimportantconsiderationsforweldjointsinthesealloysare(1)avoidanceofsolidificationcracking,and(2)preservationofcorrosionresistanceoftheweldandheat-affectedzones.Fullyausteniticwelddepositsaremoresusceptibletocrackingduringwelding.Forthisreason,Alloys316,316L,and317L"matching"fillermetalsareformulatedtosolidifywithasmallamountofferriteinthemicrostructuretominimizecrackingsusceptibility.Forweldmentstobeusedintheas-weldedconditionincorrosiveenvironments,itisadvisabletoutilizethelowcarbonAlloys316Land317Lbasemetalandfillermetals.Thehigherthecarbonlevelofthematerialbeingwelded,thegreaterthelikelihoodtheweldingthermalcycleswillallowchromiumcarbideprecipitation(sensitization),whichcouldresultinintergranularcorrosion.Thelowcarbon"L"gradesaredesignedtominimizeoravoidsensitization.High-molybdenumwelddepositsmayexperiencedegradedcorrosionresistanceinsevereenvironmentsduetomicro-segregationofmolybdenum.toovercomethiseffect,themolybdenumcontentoftheweldfillermetalshouldbeincreased.Forsomesevereapplicationforthe317Lalloys,welddepositscontaining4percentormoreofmolybdenummaybedesirable.Alloy904L(AWSER385,4.5%Mo)orAlloy625(AWSERNiCrMo-3,9%Mo)fillermetalshavebeenusedforthispurpose.Becarefultoavoidcopperorzinccontaminationintheweldzonesincetheseelementscanformlowmeltingpointcompoundswhichinturncancreateweldcracking.Alloy317L

SandmeyerSteelCompanyhastheheaviestandlargestinventoryofAlloy317Lstainlesssteelplateinthicknessesfrom3/16"through3".317L合金（UNSS31726）是以鉬為基礎的奧氏體不銹鋼。它與常規(guī)的鉻-鎳奧氏體不銹鋼如304合金相比，具有更強的抗化學腐蝕能力。另外，與常規(guī)的不銹鋼相比，317L合金具有更高的延展性、抗應力腐蝕性能、耐壓強度及耐高溫性能。它是低碳等級或L等級，這個等級具有在焊接期間及熱處理過程中抗敏化作用性能。Specs:317L

GeneralProperties

Composition

ResistancetoCorrosion

OxidationResistance

Fabrication

HeatTreatment

Welding

MechanicalProperties

PhysicalProperties

GeneralProperties

Alloy317LMNand317Laremolybdenum-bearingausteniticstainlesssteelswithgreatlyincreasedresistancetochemicalattackascomparedtotheconventionalchromium-nickelausteniticstainlesssteelssuchasAlloy304.Inaddition,317LMNand317Lalloysofferhighercreep,stress-to-rupture,andtensilestrengthsatelevatedtemperaturesthanconventionalstainlesssteels.Allarelowcarbonor"L"gradestoprovideresistancetosensitizationduringweldingandotherthermalprocesses.The"M"and"N"designationsindicatethatthecompositionscontainincreasedlevelsofmolybdenumandnitrogenrespectively.Thecombinationofmolybdenumandnitrogenisparticularlyeffectiveinenhancingresistancetopittingandcrevicecorrosion,especiallyinprocessstreamscontainingacids,chlorides,andsulfurcompoundsatelevatedtemperatures.Nitrogenalsoservestoincreasethestrengthofthesealloys.Bothalloysareintendedforsevereserviceconditionssuchasfluegasdesulfurization(FGD)systems.BacktotopCompositionChemicalCompositioninWeightPercent

perASTMA240forCitedAlloysElementType317LType317LMNCarbon0.03max0.03maxManganese2.002.00Silicon0.75max0.75maxChromium18.00-20.0017.00-20.00Nickel11.00-15.0013.50-17.50Molybden3.00-4.004.00-5.00Phosphorus0.04max0.04maxSulfur0.03max0.03maxNitrogen0.10max0.10-0.20IronBalanceBalanceUNSNo.S31703S31726*OptionalBacktotopResistancetoCorrosion

Alloys317Land317LMNstainlesssteelsaremoreresistanttoatmosphericandothermildtypesofcorrosionthanconventionalchromium-nickelstainlesssteels.Ingeneral,environmentsthatarenotcorrosiveto18Cr-8Nisteelswillnotattackalloyscontainingmolybdenum,withtheexceptionofhighlyoxidizingacidssuchasnitricacid.Alloys317LMNand317Lstainlesssteelsareconsiderablymoreresistantthanconventionalchromium-nickeltypestosolutionsofsulfuricacid.Resistanceincreaseswithalloymolybdenumcontent.Thesealloysareresistanttosulfuricacidconcentrationsupto5percentattemperaturesashighas120°F(49°C).Attemperaturesunder100°F(38°C)thesealloyshaveexcellentresistancetosolutionsofhigherconcentration.However,servicetestsarerecommendedtoaccountfortheaffectsofspecificoperatingconditionsthatmayaffectcorrosionbehavior.Inprocesseswherecondensationofsulfur-bearinggasesoccurs,thesealloysaremuchmoreresistanttoattackatthepointofcondensationthanconventionalAlloy316.Theacidconcentrationhasamarkedinfluenceontherateofattackinsuchenvironmentsandshouldbecarefullydeterminedbyservicetests.Thetablebelowcomparesthecorrosionresistanceofannealedstripsamplesof317LMNand317LstainlesssteelsinavarietyofsolutionsrelatedtotheprocessindustriesaswellasstandardASTMtests.DataonAlloys316LandAL276alloyareresentedforcomparison.CorrosionResistanceinBoilingSolutionsandASTMTestsTest

SolutionCorrosionRateinMilsperYear(mm/y)

forCitedAlloysAlloy

316LAlloy

317LAlloy

317LMNAlloy

27620%

AceticAcid0.12

(<0.01)0.48

(0.01)0.12

(<0.01)0.48

(0.01)45%

FormicAcid23.41

(0.60)18.37

(0.47)11.76

(0.30)2.76

(0.07)10%

OxalicAcid48.03

(1.23)44.90

(1.14)35.76

(0.91)11.24

(0.28)20%

Phosphoric

Acid0.06

(0.02)0.72

(0.02)0.24

(<0.01)0.36

(0.01)10%

SulfuricAcid635.7

(16.15)298.28

(7.58)157.80

(4.01)13.93

(0.35)10%

Sodium

Bisulfate71.57

(1.82)55.76

(1.42)15.60

(0.40)2.64

(0.07)50%

Sodium

Hydroxide77.69

(1.92)32.78

(0.83)85.68

(2.18)17.77

(0.45)ASTMA262

PracticeB

(FeSO4H2SO4)26.04

(0.66)20.76

(0.53)17.28

(0.44)264.5

(6.72)ASTMA262

PracticeC

(65%HNO3)22.31

(0.56)19.68

(0.50)16.32

(0.42)908.0

(23.06)ASTMA262

PracticeE

(Cu?CUSO4?H2SO4)PassPassPassPassThelowcarbon(lessthan0.03%)ofthesealloyseffectivelypreventssensitizationtointergranularcorrosionduringthermalprocessessuchasweldingorforging.Thehigherchromiumcontentsof317LMNandAlloy317Lstainlesssteelsalsoprovidesuperiorresistancetointergranularattack.Itshouldbenotedthatprolongedexposureintherange800to1400°F(427-816°C)canbedetrimentaltointergranularcorrosionresistanceandmayalsocauseembrittlementduetoprecipitationofsigmaphase.Thehighernitrogencontentofthe317LMNalloyretardstheprecipitationofsigmaphaseaswellascarbides.PittingResistanceEquivalentsAlloyPREAlloy31625Alloy317L30317LMN38Alloy62552AlloyC27669HighmolybdenumandnitrogencontentscansignificantlyimprovepittingresistanceasillustratedintheprecedingtableofPittingResistanceEquivalents(PRE).ThePREisbasedontheresultsofcorrosiontestsinwhichitwasfoundthatnitrogenwas30timesmoreeffectivethanchromiumandapproximately9timesmoreeffectivethanmolybdenuminenhancingchloridepittingresistance.ThetemperatureoftheonsetofcrevicecorrosionasdeterminedinamodifiedASTG-48Btestisausefulmeansofrankingtherelativeresistanceofstainlessandnickel-basealloys.TheCriticalCreviceCorrosionTemperaturestablethatfollowsdemonstratesthatcrevicecorrosionresistanceforausteniticstainlesssteelsincreaseswiththealloy'smolybdenumandnitrogencontent.CreviceCorrosioninaSimulated

FGDSystemEnvironmentAlloyWeightLoss(g/cm2)

forTests*atCitedTemperatures24°C

(75°F)50°C

(122°F)70°C

(158°F)Type317L0.00070.03770.0500317LMN0.00000.01290.0462Alloy6250.00000.00000.0149AlloyC2760.00000.00010.0004*72-hourexposurebasedonASTMG-48Bprocedureusingthefollowingsolution:

7vol.%H2SO4,3vol%HCI,1wt%CuCl2,1wt%FeCl3BacktotopOxidationResistance

Thechromium-nickel-molybdenumsteelsallhaveexcellentresistancetooxidationandalowrateofscalinginordinaryatmospheresattemperaturesupto1600-1650°F(871-899°C).BacktotopFabrication

Thephysicalandmechanicalpropertiesof317LMNandAlloy317Lstainlesssteelsaresimilartothoseofmoreconventionalausteniticstainlesssteelsandcan,therefore,befabricatedinamannersimilartoAlloys304and316.BacktotopHeatTreatment

Forging

Therecommendedinitialtemperaturerangeis2100-2200°F(1150-1205°C)withafinishingrangeof1700-1750°F(927-955°C).Annealing

317LMNandAlloy317Lstainlesssteelscanbeannealedinthetemperaturerange1975-2150°F(1080-1175°C)followedb