简介：Inthispaper,aslowbendingspeedvarestrainttestmethodwithcon-tinuouslyadjustabledeformationratefortestinghotcrackingsensitivityisde-velopedanditsworkingprincipleisdescribed.Fromgreatamountsoftests,itisknownthatstrainrateaffectsthesensitivityofsolidificationcrackbecauseofitsinflunceonmaterialductilityinBTRdirectly.Thesmallerthestrainrate,thebettertheductilityandthelowerthesolidificationcracksensitivity.Theex-tentofthiseffectvarieswithdifferentmaterials,forLF-6aluminumalloy,itisgreat,butfor16Mn,19Mn5and20Gsteels,itissmall.Throughsystematicinvestigation,itisconcludedthatstrainrateofametalduringweldingcanbeloweredandtheresistancetosolidificationcrackcanbeenhancedbyreducingstructrualrestraintandbyadjustmentofweldingparameters.

简介：Anexperimentfordeterminingthelaser-TIGhybridweldingcharacteristicswascarriedoutinthreekindsofhybridmethods:CO2laser-TIGcoaxialhybrid,CO2laser-TIGparaxialhybridandNd:YAGlaser-TIGparaxialhybrid.TheexperimentalresultsindicatethathybridweldinghastwoweldingmechanismsinCO2laser-TIGhybridwelding:deeppenetrationweldingandheatconductionwelding.Astheeffectofthelaser-inducedkeyhole,thearcrootiscondensed,thecurrentdensityandpenetrationdepthincreasesignificantly,theweldingcharacteristicisapttodeeppenetrationwelding.Whencurrentincreasestosomedegree,thekeyholeinducedbylaserdisappears,whichproducesashallowpenetrationandwidebead.Theweldexhibitsheatconductionweldingcharacteristics.Furthermore,thearcimagesandweldbeadcross-sectionsofthreekindsofhybridmannerswerealsocomparedandanalyzedatdifferentweldingcurrents,whichestablishedthefoundationforunderstandingtheweldingcharacteristicsoflaser-TIGhybridweldingcomprehensively.

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简介：Thisstudydevelopedasequentialcouplingfiniteelementproceduretopredictresidualstressesofsteelpipeswithlongitudinalwela\circumferentialweldandspiralweld.Theresultsshowthattheresidualstressinheataffectedzone(HAZ)ishigherthanthatinweldforspiralweldpipe.Forthecircumferentialweldpipeandspiralweldpipe,theresidualstressininnersurfaceishigherthanthatinoutersurface.However,forthespiralweldpipe,theresidualstressininnersurfaceissmallerthanthatinoutersurface.Thehoopresidualstressofcircumferentialweldpipeishigherthanthatoflongitudinalweldpipe,whiletheaxialresidualstressofcircumferentialweldpipeissmallerthanthatoflongitudinalweldpipe.Thehoopstressesforcircumferentialweldpipeandaxialstressforlongitudinalweldpipehaveexceededtheyieldstrengthofbasemetal.Withtheincreaseofhelixangle,thehoopstressdecreaseswhiletheaxialstressincreases.Forthespiralpipe(α=30°to50°),boththehoopstressandaxialstressarerelativelysmall.Thespiralpipe(helixanglerangingfrom30°to50°)ishelpfultoreducestresscorrosioncracking(SCC)anditisrecommendedtomanufacturethesteelpipe.

简介：Ti-basedfillermetalsmadebytransientsolidificationandnormalcrystallizationwereselectedforthevacuumbrazingoftheTiAlalloyand42CrMounderdifferentprocessingparameters.Theresultsshowthatthetensilestrengthofthejointoftransientsolidifiedfillermetalishigherthanthatofnormalcrystallizedfillermetalunderthesameprocessingparameters.Bytheanalysisofscanningelectronmicroscope(SEM)andX-raydiffracting(XRD),itisfoundthatthehigherstrengthmaybecausedbythegeneratingofTiAl,TiNiandTiCuattheinterfaceofjointmadebytransientsolidifiedfillermetal.

简介：TIGweldingwasusedtodepositCo-8.8Al-9.8W-0.2Bsuperalloyon304austenitestainlesssteel.Theformfactorofweld,dilutionratio,microhardness,microstructureanddistributionofalloyingelementswereinvestigated.Themicrostructureofcladdinglayerwasmainlyhypoeutectic.Theprimaryphaseswerecobalt-richsolidsolution.Theeutecticphasewascomposedofcobalt-richsolidsolution,Co6W6CandCoCx.Whentheboroncontentincreasedfrom0.2%to0.5%,thedilutionratiodecreased,theprimaryphasebecamecoarseandthemicrohardnessdecreased.Whentheboroncontentwasfrom0.5%to2%,thedilutionratioandmicrohardnessincreasedobviously,buttheprimaryphasewasrefined.ThehardphaseofCo-8.8Al-9.8Wbecamerefinedandtheamountwasraised,andtheperformanceofcladdinglayerwasimprovedwithappropriateboronincrease.

简介：Weldshapecontrolisafundamentalissueinautomaticwelding.Inthispaper,adoublesidevisualsystemisestablishedforpulsedgasmetalarcwelding(P-GMAW),andbothtopsideandbacksideweldpoolimagescanbecapturedandstoredcontinuouslyinrealtime.Byanalyzingtheweldshaperegulationwiththemoltenmetalvolume,sometopsideweldpoolcharacterizedparameters(WPCPs)areproposedfordeterminingpenetrationinbuttweldingofthinmildsteel.Moreover,someBPnetworkmodelsareestablishedtopredictbacksideweldpoolwidthwithweldingparametersandWPCPsasinputs.

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