简介：Itisofgreatimportanceforobtainingtheperfectweldingpropertiestocontroltheacicularferrite(AF)transformationbehaviorreasonablyinsteelweld.AFcontinuoustransformationkineticsintheHSLAsteelweldwascalculatedandmodeledbasedonthedirectgrowthontheinclusionsinertinterface.Thesimulationresultsarecoincidentwiththeexperimentalvaluewell.

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简介：Themechanicalproperties,creepdamage,creeprupturestrengthandfeaturesofinterfacialfailuresofweldedjointsbetweenmartensite(SA213T91)andpearlitesteel(12Cr1MoV)havebeeninvestigatedbymeansofargontungstenpulsedarcwelding,hightemperatureacceleratedsimulation,creeprupture,mechanicalpropertytestsandscanningelectronicmicroscope(SEM).Theresearchresultsindicatethatthemechanicalpropertiesofovermatchedandmediummatchedjointdeteriorateobviously,andtheyaresusceptibletocreepdamageandfailureafteracceleratedsimulationoperation500h,intheconditionofpreheat250℃,andpostweldingheattreatment750℃×1h.However,themechanicalpropertiesofundermatchedjointarethebest,theinterfacialfailuretendencyofundermatchedweldedjointislessthanthoseofmediumandovermatchedweldedjoint.Therefore,itisreasonablethatlowalloymaterialTR31isusedasthefillermetalofweldbetweenSA213T91and12Cr1MoVsteel.

简介：Anewhardfacingprocess,reactivebrazecoatingprocess(RBCC)wasstudied,and(TiC+Cr3C2)/FecompositecoatingswerepreparedbyRBCCusingcarbon,Cr3C2,iron,ferrochromiumandtitaniumpowderastherawmaterialsinvacuumbrazefurnace.TheresultsshowthatTiCisin-situsynthesizedinthecoatings.ThemethodsofintroducingCr3C2havegreateffectsonthedistributionofTiC.AddingCr3C2directlytotherawmaterialsforcoatings,fineTiCparticlesaggregateintodiscoidsparalleltothecoatingsurface,whereas,in-situsynthesizingCr3C2incoatings,theaggregationsofTiCarelumpish.Duringbrazecoating,Cr3C2particlesdirectlyaddeddissolveandprecipitatetobecomeneedle-shaped.Thecoatingshaveanevenandsmoothsurfaceandarecombinedwiththeirmildsteelsubstratesbyametallurgicalbonding.

简介：Theeffectofnonmetallicinclusionsinthedropletofthestainlesssteelcoveredelectrodeontheporositywasresearched.Theresultshowsthatthenonmetallicinclusionsinthedropletarespherical,theircompositionisdifferentfromtheoneofslagandtheinclusionshavethecharacterof"innerformation".Whentheratioofrutiletoilmeniteinthecoatedmaterialisincreased,thedropletbecomescoarse,thecontentofnonmetallicinclusioninthedropletdecreases,andtheporositysensitivityintheweldmetalalsodecreases.Whentheratiooffledspartoilmeniteinthecoatedmaterialisincreased,thedropletbecomesfine,thecontentofnonmetallicinclusioninthedropletincreases,andtheporositysensitivityintheweldmetalincreases.WhentheratioofFe2O3toilmeniteinthecoatedmaterialisincreased,thedropletbecomesfine,thecontentofnonmetallicinclusiondecreases,whiletheporositysensitivitydoesnotreduce.

简介：EffectsofalloyelementsonthemicrostructureandcrackresistanceofFe-C-Crweldsurfacinglayerwereinvestigated.Theresultsshowthatmicrostructuresofthelayermainlyconsistofcarbidesandaustenitematrix.IncreasingCandCrcontentsimpairthecrackresistanceofthelayerduetoincreasedamountofbrittlecarbides.TheadditionofNi,NborMoimprovesthecrackresistanceofFe-C-CrweldsurfacinglayerbyincreasingtheamountofausteniteandformingfineNbCorM7C3carbidesinthelayer.But,theexcessiveNb(>2.50wt%)orMo(>1.88wt%)impairsthecrackresistanceofthelayer,whichhasrelationwithincreasedcarbidesorcarbidecoarseningandaustenitematrixsolidsolutionstrengthening.ThepropercombinationofC,Cr,Ni,NbandMocanfurtherimprovenotonlythecrackresistanceofFe-C-CrweldsurfacinglayerbutalsotheerosionresistanceasaresultoffineNbCandM7C3carbidesdistributinguniformlyinaustenitematrix.Theoptimallayercompositionsare3.05wt%C,20.58wt%Cr,1.75wt%Ni,2.00wt%Nband1.88wt%Mo.

简介：ButtjointsofQCrO.8/1Cr2lNiSTiequal-thicknessdissimilarmaterialswereobtainedbyelectronbeamweldingwithfixedacceleratingvoltage60kVandfocuscurrent1.99A,changedelectronbeamcurrentandweldingvelocity.MicrostructureandcompositionoftheEBWjointwereinvestigatedbymeansofopticalmicrographyandEDXanalysis,mechanicalpropertiesofthejointwerealsotested.Theresultsshowthatjoint'smacrostructurewasdividedintothreezones:topweldzonenearQCrO.8andbottomweldzoneconsistingofCu(ss.Fe)withacertainamountofdispersedlydistributed(α+ε)mixedmicrostructure,middleweldzoneconsistingof(α+ε)microstracturewithasmallamountofCu(ss.Fe)particles.MorphologicalinhomogeneousmacrostructureandunevenchemicalcompostionofQCrO.8/1Cr21NiSTijointbyEBWarethemostimportantfactortoresultindecreasingjoiningstrength.

简介：北京市东升电焊机厂生产的ZX7-400ST手/氩两用焊机是具有国内先进水平、高效节能的焊接设备,具有直流手工电弧焊和直流氩弧焊两种工作方式。该焊机使用IGBT模块为开关元件,采用脉宽调制技术实现电流控制,具有良好的动特性和电网波动自动补偿功