简介:Problemsencounteredintheproductionoflownickelausteniticstainlesssteelhavebeenstudied.Theseproblemsprimarilyincludethechangestothemicrostructureoftheslabduringtheheatingprocess,theformationandremovalofdeformation-inducedmartensiteduringcoldrolling,andtheeffectsoftheannealingprocessonthesurfaceoxidestructure.Areasonablemanufacturingprocesshasbeenproposedonthebasisoftheresearchresultsandhighqualitycold-rolledstripsoflownickelausteniticstainlesssteelhavebeenproduced.
简介:Inrecentyears,nitrogen-alloyedstainlesssteelshavebeenaresearchhotspotinthefieldofstainlesssteelproductandtechnology.Nitrogen-alloyedausteniticstainlesssteelsdevelopedbyBaosteelandtheirapplicationsareintroduced.Thesesteelsarenitrogen-controlledproducts304Nand316LN,nitrogencontainingeconomicalproductsBNseriesandhigh-nitrogenstainlesssteel(HNS)series.Theresultsshowthatthepresenceofnitrogencansignificantlyimprovethestrengthandcorrosionresistanceofsteelproduced.Bynitrogenalloying,economicalausteniticstainlesssteelswithconsiderablylessnickelthan304canbeobtained;thecorrosionresistancesofthesesteelsarealmostthesameas304.Furthermore,byascientificapproachofnitrogenalloying,high-nitrogensteelof0.8%nitrogencontentisfabricatedunderthenon-pressurizedconditions,andthepittingpotentialofthissteelis>1.0V.Atpresent,nitrogen-alloyedsteelsdevelopedbyBaosteelarewidelyutilizedinthemanufactureofcryogenicstoragecontainers,transportationcontainers,andmanyhouseholdwares.
简介:309Lisakindofausteniticstainlesssteel.Thispaperdiscusses309L,whichwassmeltedandrolledinalab.Itsmicrostructuralcharacteristicsinstatesofas-cast,hot-rolling,cold-rollingandsolidsolutionwereinvestigatedrespectivelybyopticalmicroscope(OM).Itisfoundthat309Liscomposedofausteniteandresidualδ-ferriteundertheseconditions,andtheδ-ferritecannotbeeliminatedeasilybyheat-treatment.Itshotplasticityanddeformationresistancewereinvestigatedinaseriesofheatsim...
简介:CuprecipitationbehaviorsintwoCu-bearingausteniticantibacterialstainlesssteels,type304andtype317L,weresystematicallystudiedbyusingrelativelysimplemethodsformaterialsanalysis,includingmicro-hardness,electricalresistivity,electrochemicalimpedancespectroscopy,X-raydiffractionanddifferentialscanningcalorimetry.Theresultsindicatedthatafteragingatelevatedtemperature,themicro-hardness,electricalresistivity,electrochemicalimpedanceandlatticeconstantofthesteelwereallvariedatdifferentdegreesduetotheprecipitationandgrowthofCu-richphases.TheresultsalsoshowedthattheheatevolutionduringtheprocessofCuprecipitationcouldbesensitivelydetectedbymeansofdifferentialscanningcalorimetry,obtainningthestartingtemperature,peaktemperature,peakareaoftheCu-richprecipitation,andeventheactivationenergybycalculation.TheresultsconfirmedthattheCu-richphasedprecipitationintheCu-bearingausteniticantibacterialstainlesssteelshouldbeathermalactivationprocesscontrolledbyCudiffusion.AllthematerialsanalysismethodsusedinthisstudycanbemoresimpleandeffectiveforapplicationinR&DoftheCu-bearingantibacterialstainlesssteels.
简介:Twothermo-mechanicalcontrolledprocesses(TMCP)includingcontrolledrollingandacceleratedcoolingareproposedfortheproductionofheavygaugeSUS304Lausteniticstainlesssteelplateswithdifferentstrengthsandothercharacteristics.BasedontherecrystallizationmechanismandcarbideprecipitationbehaviorofSUS304Lausteniticstainlesssteel,TMCPprovidesapowerfulmeanstocontrolthemicrostructureandprecipitationofthehotrolledsteelplatebythecontrolledrollingandacceleratedcoolingprocess.Thedislocationdensityandgrainsizearethemainfactorsindeterminingthestrengthofthestainlesssteelplates.Therefore,itisnecessarytostrictlycontrolthehotrollingparameters,includingparameterssuchasthefinishhotrollingtemperatureintherecrystallizationtemperatureregionandthetotalreductioninthenon-recrystallizationregion.Furthermore,inordertoavoidcarbideprecipitationandguaranteetheintergranularcorrosionresistanceofTMCPSUS304Lausteniticstainlesssteel,acriticalcoolingrateafterrollingisdetermined.
简介:Toavoidintergranularcorrosionandobtainmicrostructuralhomogenization,theconventionalSUS304austeniticstainlesssteelneedstobesolutionannealedafterhotrolling.Thisstudyinvestigatesthethermal-mechanicalcontrolledprocess(TMCP)ofSUS304steel,especiallythecontrolledrollingandonlineacceleratedcoolingprocedures.Theobjectiveofthisresearchistoreduceorevenpreventcarbideprecipitationbasedonthedescriptionofthetime-temperature-precipitation(TTP)curve.Thedynamicandpost-dynamicrecrystallizationbehaviorsofthissteelensuredthehomogenizationofgrainsinthisprocessdueto,whichwasstudiedbythehotcompressiontests.ThemicrostructureandthepropertiesoftheTMCP-producedSUS304steelstripwerecomparedwiththeconventionalmethodofsolutionannealing.Basedontheaboveresults,thenewlydevelopedTMCP-producedSUS304hot-rolledausteniticstainlesssteelstriphasbeensuccessfullyproducedanditcanbedirectlyutilizedinthecoldrollingprocesswithoutsolutionannealing.
简介:FSWandTIGwereconductedon316Lstainlesssteel.Variationduringmicrostructureandpropertiesinjointsobtainedbydifferentweldingmethodswasstudied.TheresultsshowthattheeffectofseveremechanicalstirringandintenseplasticdeformationcreatafinerecrystallizedgrainintheweldingjointduringFSW.AsforTIG,thetemperatureofweldingjointexceedsthemeltingpointofweldedmaterialitself.Theentireweldingprocessbelongstothesolidificationofasmallmoltenpool;andthemicrostructureofthejointtakesonatypicalcastingstructure.Whentheweldingparameterswereselectedappropriately,theaverageultimatetensilestrengthofFSWjointscanreach493MPa,whichis83.6%ofbasemetal;theaverageelongationis52.1%ofbasemetal.TheaverageultimatetensilestrengthofTIGjointsis475MPa,whichis80.5%ofbasemetal;theaverageelongationis40.8%ofbasemetal.ThetensiletestofFSWjointsissuperiortotheTIGjoints.ThemicrohardnessofFSWjointcomparedtobasemetalandTIGjointhavingasignificantimprovement,whicharel95.5HV,159.7HVand160.7HV,respectively;grainrefinementstrengtheningplaysanimportantroleinenhancingthemicrohardness.TheelectrochemicalcorrosiontestsshowthatthejointofFSW316Lausteniticstainlesssteelhasagoodcorrosionresistance.
简介:Improvingtheunitheatefficiency,reducingcoalconsumptionandtheemissionofCO2andmeetingtherequirementsofenvironmentalprotectionandenergyconservationisthegoaloftheboilerandthepowerindustry.Developmentsoflargecapacityandhighparameterultra-supercritical(USC)unitsarethetendencyofthepowerindustry.ThereisnodoubtthatthedevelopmentofUSCunitsisbasedonthedevelopmentofmaterials,especiallythematerialsusedforsuper-heaterandreheaterinhigh-temperatureUSCboiler.Duetothelongtimeexposuretotheharshenvironment,suchasbearingthe600℃steamoxidation,andwithstandingthecorrosivefluegasandflyasherosion,thematerialsrequirenotonlygoodhigh-temperaturestrength,butalsoagoodcorrosionresistance.Inconsiderationoftherequirementscitedabove,foreigncountrieshaddevelopedTP310HCbN(07Cr25Ni21CbN)austeniticheat-resistantsteel.However,thedomesticdemandsforthismaterialstilldependonimportandthecostishigh,sotheboilerandthepowerindustryexpectseagerlythatthesesteelscanbeproducedbydomesticmetallurgicalindustry,especiallyBaosteel,toreplacetheimportedproducts.Inordertosatisfytherequirementsofdomesticmanufacturingsuper-heaterandreheaterusedinultra-supercriticalpowerboiler,afterdevelopedT23、T91、T92、S30432highpressureboilertube,BaosteelbegantodevelopTP310HCbN(07Cr25Ni21CbN)austeniticstainlesssteeltubeinJanuaryof2007.Thisstudydescribesthecompositiondesign,themanufacturingprocessofproduct,andtheassessmentofperformanceofBaosteel’sTP310HCbN(07Cr25Ni21CbN).ThedataindicatesthatpropertiesofBaosteel’sTP310HCbN(07Cr25Ni21CbN)conformtotheASMESA-213standardandGB5310standard,soitcansubstitutetheimportedproductsandissuitableformanufacturingpowerstationboilerofgreatcapacityandhighsteamparameters.
简介:Thestudyintroducesthechemicalcomposition,mechanicalproperties,physicalpropertiesandproductionprocessesoftheFe-23Mn-2Al-Vausteniticsteel.Investigationsweremadeintotheformationofcracksinthehot-rolledFe-23Mn-2Al-Vsteelplates,withopticalmicroscopy(OM),scanningelectronmicroscopy(SEM)andenergydispersivespectrum(EDS).Theresultshaveshownthatintergranularoxidationinthereheatingfurnaceisthemaincauseofthecracksonthesurfaceofthehot-rolledsteelplates.Thesurfacecrackingcanbelargelyavoidedbycontrollingtheremainingoxygencontentinthereheatingfurnaceandimprovingcontinuouscasting(CC)processestoincreasethethicknessoffineequiaxedgrainlayerofthesteelslabs.