简介:WeldingresearchofA6N01S-T5aluminumalloyprofileforhigh-speedtrainwasdonebyusinglaser-MIGhybridweldingandMIGweldingindividually.Andtheweldappearance,weldingdistortion,mechanicalpropertiesofthejointsandmicrostructureswereanalyzed.Thetestresultsdemonstratedthathigh-efficientweldingfortheprofilecanbeachievedbyusinglaser-MIGhybridwelding,thespeedofwhichcanbeover3.0m/min.Theprocessinghadagoodgapbridgingability,evenifthegapofthebuttjointwasupto2.0mm,agoodweldappearancecanalsobegot.Whilethehybridweldingspeedwasgreaterthan2.5m/min,theweldingdistortionofthelaser-tandemMIGhybridjointswasjustabout33%ofthatoftheMIGjoints,buttheweldingefficiencywasover3timesofMIGwelding.Andtensilestrengthofthehybridjointswas85%ofthatofA6N01S-T5basemetal,9%higherthanthatoftheMIGjoints.Fatiguepropertieswastestedindividuallywithpulsedtensilefatiguemethodintheconditionof1×107lifetime.Thetestresultsdemonstratedthatthefatiguestrengthofthejointswasalittlelowerthanthatofbasematerial,whichcouldbeupto115MPa.Butthefatiguestrengthofhybridweldingjointswas107.5MPa,whichwas23%higherthan87MPaofMIGweldingjoints.
简介:DD6alloywasbondedbytransientliquidphase(TLP)diffusionbonding.Themaincompositionsoftheinterlayeralloyemployedweresimilartothoseofthebasemetal,DD6,andacertainamountofelementBwasaddedasthemeltingpointdepressant.Theresultsshowthatitisdifficulttoobtainthejointswiththemicrostructurescompletelyhomogeneous.ForthejointTLPdiffusionbondedat1290℃for12h,abouthalfareasofthebeampossessedαγ+γ′microstructure,nearlyidenticalwiththatofthebasemetal,andtheotherlocalareasconsistedofT-solution,borides,etc.Prolongingthebondingtimeto24h,theinhomogeneousareasinthejointreduced,andthejointpropertyimproved.Thejointstress-rupturestrengthat980℃and1100℃reached90%-100%and70%-80%ofthoseofthebasemetalrespectively.
简介:Theeffectofnonmetallicinclusionsinthedropletofthestainlesssteelcoveredelectrodeontheporositywasresearched.Theresultshowsthatthenonmetallicinclusionsinthedropletarespherical,theircompositionisdifferentfromtheoneofslagandtheinclusionshavethecharacterof"innerformation".Whentheratioofrutiletoilmeniteinthecoatedmaterialisincreased,thedropletbecomescoarse,thecontentofnonmetallicinclusioninthedropletdecreases,andtheporositysensitivityintheweldmetalalsodecreases.Whentheratiooffledspartoilmeniteinthecoatedmaterialisincreased,thedropletbecomesfine,thecontentofnonmetallicinclusioninthedropletincreases,andtheporositysensitivityintheweldmetalincreases.WhentheratioofFe2O3toilmeniteinthecoatedmaterialisincreased,thedropletbecomesfine,thecontentofnonmetallicinclusiondecreases,whiletheporositysensitivitydoesnotreduce.
简介:FlameheatingcombinedwithwatercoolingwasusedtostraightenA6N01aluminumalloyweldedjointandeffectofflameheatingpassonitsmicrostructureandmechanicalpropertieswasstudied.ResultsshowedthattheflameinducedtheprecipitationandgrowthoftheMg2SiphaseontheAlsubstrateforthethermalagingA6N01aluminumalloyweldedjoints,thusitledthedecreaseofmicro-hardnessandtensilestrengthoftheA6N01aluminumalloyweldedjointwiththeincreaseoftheheatingpass.However,thefatiguepropertyoftheflameheatedjointwasimprovedbecausetheMg2Siprecipitationhinderedtheinitiationandpropagationofthefatiguecrack.
简介:Inthispaper,6mmthick2219-T6aluminumalloywasjoinedbymeansofvariablepolaritytungsten-arcwelding(VP-TIG)andtheinfluenceofgradientmismatchesonVP-TIGjointsisinvestigated.Theaveragetensilestrengthofthejointsreduces32%,53%and59%,whenthemismatchofthejointwas0.635mm,1.44mm,1.83mm,respectively.Incompletepenetration,additionalbendingmoment(Ma)anddecreaseofeffectiveloadregionareaareconsideredtoexplainthisphenomenon.Thefracturelocationoftensilespecimensoccurredattheweldzone(WZ)closetopartialmeltzone(PMZ),correspondingtoasharpdeclineofmicrohardnessfromPMZtoWZ.Theoriginalpositionoffractureisfoundatweldtoe,whereincompletepenetrationformsduetotheintroductionofgradientmismatches.
简介:ThesusceptibilityofweldedjointfortheX65pipelinesteeltoH2Sstresscorrosioncracking(SCC)isinvestigated.SCCtestsonthesteelarecarriedoutintheenvironmentbasedonNACETM-01-77solutionwithsaturatedgaseousH2S.Thethresholdstressintensityfactorandcrackpropagationvelocityarecalculatedaccordingtowedge-openingloading(WOL)specimens.Thethree-dimensionalelastic-plasticfiniteelementanalysisofWOLspecimensisperformedbyusingtheFEMprogrammingpackageANSYS.Stressfieldandconcentrationofhydrogendistributionpropertyaheadofthecracktipareobtained.ThispapersurveyedthemicrostructureofweldedjointandstudiedonthemechanicalpropertiesofX65pipelinesteel.Itprovidesexperimentalbasisforstudyingstresscorrosion.Theresultsofnumericalanalysisareconsistentwithconclusionsofstresscorrosiontest.
简介:Stationaryshoulderfrictionstirlapwelding(SSFSLW)wassuccessfullyusedtoweld6005A-T6aluminumalloyinthispaper.EffectofpinrotatingspeedoncrosssectionmorphologiesandlapshearstrengthoftheSSFSLWjointsweremainlydiscussed.Resultsshowthatjointswithoutflashandshouldermarkscanbeobtainedbythestationaryshoulder.CrosssectionoftheSSFSLWjointpresentsabasin-likemorphologyandlittlematerialloss.Byincreasingtherotatingspeedfrom1000rpmto1600rpm,botheffectivesheetthicknessandlapwidthincrease,whilelapshearfailureloadfirstlydecreasesandthenincreases.Themaximumfailureloadof14.05kNisattainedwhen1000rpmisused.AllSSFSLWjointspresentshearfracturemode.
简介:GB/T15579.5-2005《弧焊设备安全要求第五部分:送丝装置》和GB/T15579.7-2005《弧焊设备安全要求第七部分:焊炬(枪)》(以下简称新标准)已于2005年12月1日正式实施。自新标准实施之日起.JB/T9533-1999《焊机送丝装置:技术条件》、JB/T9526-1999《TIG焊焊炬技术条件》和JB/T9532-1999《MIG/MAG焊焊枪技术条件》(以下简称旧标准)废止。