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。
简介:BondingofAl2O3tocuisperformeddirectlyusingTifoilattemperatureof1273K.Themicrostructureofthejointinterfaceisinuestigatedthroughscanningelectronmicroscope(SEM),electron.probemicroanalysis(EPMA)andX-raydiffraction(XRD).theeffectoftheinitialtifoilthicknessonthereactionlayerthicknessandthejointStrengthareinvestigated.
简介:IntheautomaticCO2arcwelding,thealterationoftheverticaldistancebetweentheweldingtorchandtheworkpiecehasastrongeffectontheweldingparameterssuchasweldingcurrentandvoltage,withtheresultthattheappearanceandqualityofweldarenotsteady.Toweakentheinfluenceofthedistancealteration,amethodisputforwardinthepaper.Themethodisthatthealternatewire-feedcontrolisusedforcompensatingtheweldingcurrent.Onthebasisoftheoreticalanalysis,astaticnumericalmodelforalternatewire-feedcontrolisestablished.Theexperimentsshowthatthemodel-basedregulationofthewirefeedratecancompensatetheweldingcurrentandensuretheappearanceofweld.Whenthealterationofverticaldistancebetweenthetorchandtheworkpieceisgreater,notonlyisthewirefeedrateregulated,buttheoutputvoltageofthepowersourceisadjustedtoensuretheappearanceandqualityofweld.
简介:ThispaperintroducesabrazingprocessbetweenAl_2O_3ceramicandInvaralloy.Al_2O_3canbebrazedwithInvareffectively.TheinterfacialstructureofAl_2O_3/Invarjointcanbeexpressedas:Invar/Ag(s,s)+Cu(s,s)+Fe_2Ti(zoneⅠ)/Ag(s,s)+Cu(s,s)+Fe_2Ti+NiTi+Cu_3Ti(zoneⅡ)/Ag(s,s)+Cu(s,s)+Cu_2Ti+Al(s,s)+TiC+TiO(zoneⅢ)/Al_2O_3.Themaximumshearstrengthof139MPawasmeasuredforas-brazedAl_2O_3/Invarjointbrazedat850℃for25minor900℃for15min.
简介:AnewkindofsimpleandflexibleCO_2weldingsystemwasdevelopedtocarryoutwaveformcontrol.ThesystemconsistedofIGBTinverter,PWMcircuitandmicroprocessorunit(MPU),inwhichtheoutputcurrentofconstantcurrent(CC)powersupplycouldbechangedaccordingtotransientphysicalstate,andthevariabledownsloperatecontrolcouldbeusedtoensureastableweldingprocess.Theweldingexperimentresultsprovedtheeffectivenessofthiscontrolapproach.
简介:Theeffectsoftwopost-weldheattreatmentprocessesonthemicrostructureandfatiguepropertiesoftheelectronbeamweldedjointsof30CrMnSiNi2Asteelwerestudied.Electronbeamlocalpost-weldheattreatment(EBLPWHT),inavacuumchamber,immediatelyafterweldingandatraditionalfurnacewholepost-weldheattreatment(FWPWHT)wereaccepted.Theexperimentalresultsshowthat,afterEBLPWHT,themainmicrostructureofweldischangedfromcoarseacicularmartensiteintolathmartensite,andbasemetalischangedfromferriteandperliteintoupperbainiteandresidualaustenite,howeverthemicrostructuresofdifferentzonesofjointsinFWPWHTconditionsaretemperedsorbite.Thefatiguecrackgrowthrateda/dNofweldsandbasemetalarenotobviouslychangedamongEBLPWHT,FWPWHTtestandas-welded(AW)test,asthemechanicalpropertiesofmaterialshaveacertainbutnotlargeeffectontheda/dNofweldedjoints.TheresistancetonearthresholdfatiguecrackgrowthdataofweldedjointscanbelargelyimprovedbyEBLPWHTanditisrelatedtomicrostructureandcrackclosureeffect.
简介:AnewsimulationmodelofCO2short-circuitingtransferweldingmaybeemployedtodevelopanewpatternofweldingmachineandtopredictweldingprocessparameterstoobtaintheoptimumweldingtechnologyproperties.Inthispaper,anewsimulatingmodelisdevelopedaccordingtotheAWP(adaptingweldingphysicsprocess)waveformcontrolmethod.Goodagreementisshownbetweenthepredictedandexperimentallydeterminedresults.ThemodelwillmakeanimportantpromotioninthedevelopmentofCO2arcweldingtechnique.
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.