简介：TheZrcoatingwasdepositedontitaniumsurfaceusingthemagnetronsputteringtechnique.EffectsofZrcoatingonmicrostructureandmechanicalpropertiesofporcelainfiredtotitaniumhavebeeninvestigated.Theresultsshowthatinterdiffusionofelementsoccursduringporcelainfiring,andtheZrcoatingcaneffectivelyprotecttitaniumsurfacefromexcessoxidation.ThestrengthofbondzonewithZrcoatingdepositedfor1hourreaches29.7MPa,whichhasincreasedby26.4%ascomparedwiththatofbondzonewithoutcoating(23.5MPa).

简介：Fordifferentstrengthmatching,thereliabilityindexandfailureprobabilityofweldedpressurepipewithcircumferentialsurfacecrackwerecalculatedusingthreedimensionalstochasticfiniteelementmethod.Thismethodhasovercometheshortcomingsofconservativeresultsinsafetyassessmentwithdeterministicfracturemechanicsmethod.Theeffectsofexternalmomentandthedepthofthecircumferentialsurfacecrack(a)onthereliabilityofpressurepipewerealsocalculatedanddiscussed.Thecalculationresultsindicatethatthestrengthmatchinghascertaineffectonthereliabilityoftheweldedpressurepipewithcircumferentialsurfacecrack.Thefailureprobabilityofweldedpressurepipewithhighstrengthmatchingislowerthanthatwithlowstrengthmatchingatthesameconditions.Theeffectsofstrengthmatchingonthefailureprobabilityandreliabilityindexincreasedbyaddingexternalmoment(M)andthedepthofthecircumferentialsurfacecrack(a).

简介：ＭｅｃｈａｎｉｃａｌｓｔｒｅｎｇｔｈａｎａｌｙｓｉｓｏｆＳＭＴｓｏｌｄｅｒｊｏｉｎｔｓｂｙｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｔｈｏｄ￥ＷＡＮＧＣｈｕｎｑｉｎｇ；ＷＡＮＧＲｕｉｊｕｎ；ＳＡＮＧＹａｎａｎｄＱＩＡＮＹｉｙｕ（ＷｅｌｄｉｎｇＤｅｐａｒｔｍｅｎｔ...

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简介：ＥｆｆｅｃｔｓｏｆｓｔｒｅｎｇｔｈｍａｔｃｈｉｎｇａｎｄｃｒａｃｋｄｅｐｔｈｏｎｔｈｅｆｒａｃｔｕｒｅｐａｒａｍｅｔｅｒｓｆｏｒｗｅｌｄｅｄｊｏｉｎｔｓＴａｎｇＷｅｉａｎｄＳｈｉＹａｏｗｕ（Ｘｉ＇ａｎＪｉａｏｔｏｎｇＵｎｉｖｅｒｓｉｔｙ）Ａｂｓｔｒａ...

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简介：MechanicalpropertiesofSMAW(shieldedmetalarcwelding)weldmetal(yieldstrengthhigherthan900MPa)withsystematicadditionsofcopper(upto1.48wt%)weretested.Themicrostructureandprecipitatesindifferentregionswereanalyzedbyopticalmicroscopeandtransmissionelectronmicroscope.Theresultsindicatethatcopperimprovesthelowtemperaturetoughnessofweldmetalwhenthecoppercontentislowandreachesthepeakvalue48J(at-50℃)with0.2wt%copperadditions.Whenthecontentishighthecopperprecipitatesasε-Cuphaseinthereheatzoneofmiddlebeads.Theseprecipitatesimprovethestrengthoftheweldmetalevidently(yieldstrengthupto975MPa)withoutobviouseffectonthelowtemperaturetoughness.Thecopperwithin1.1wt%contentcanimprovethestrengthwithouttoughnessloss.

简介：Fromtheviewpointofweldingmechanics,twonewweldingmethods-weldingwithtrailingpeeningandweldingwithtrailingimpactiverollingwereintroduced.Foraluminumalloythin-shellstructureswithhighstrength,weldingwillleadtohotcracking,poorjointanddistortion.Inordertosolvethem,trailingimpactivedevicewasusedbehindweldingtorchtoimpactthedifferentpositionsofweldedjoints,thusrealizingtheweldingwithfree-hotcracking,lowdistortionandjointstrengthening.Byuseofimpactiverollingwheelsinsteadofpeeningheads,theoutlookofweldedspecimencanbeimprovedandstressconcentrationatweldtoescanbereduced.Equipmentofthistechnologyissimpleandportable.Itcanusedtoweldsheets,longitudinalandring-likebeamsoftube-likestructures,aswellasthethin-shellstructureswithclosedweldssuchasflangesandhatches.Sothetechnologyhasthewideapplicationforegroundinthefieldsofaviationandaerospace.

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简介：Thehigh-speedcamerasystemanddataacquisitionsystemofweldingparameterswerecreatedintandemMIGweldingofhighstrengthaluminumalloy.Theexperimentswerecarriedoutinordertoobtainthephotosofdroplettransferunderdifferentweldingparametersinpulsedmode.Thedroplettransfermodeof"onepulseonedroplet"becomesthepreferredselectionduringweldingprocessbecauseofitsstableprocedureandsoundweldform.Theparameterrangesforcorrespondingtransfermodewereexperimentallyachieved,amongwhichthestabledroplettransfermodeof"onepulseonedroplet"canberealized.Theseeffortsbravethewayforcontrolweldheatinputandweldformationinthefuture.

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简介：Inthispaper,thelocationparameterδαinWeibulldistributioni.e.thelowerlimitingCTODtoughnessofhighstreengthsteelweldmentsisevalvated.formGleelesimulatedcoarsegrainedspecimens.TheCharpy-Vtransitiontem-peratureobtainedfromthesespecimensistransformedtoafracturetoughnessKICvalueatagiventemperatureusingSanz’relation.Then,thelocationparameterδαisevaluated.ThepredictedlocationparameterarrivesatagreementwiththelowestCTODvalueasobtainedfromthickmultilayerweldments.TheimprovementofthefracturetoughnessofmultilayerweldmentsneedstheincreaseoftheloweringlimitingCTOD.toughnessi.e.thetoughnessofthecoaregrainedzone.

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简介：Thispaperstudiesmechanicalpropertyandfractographyoftheweldedjointsobtainedindifferentweldingparameterssuchasweldingheatandweldingpresswith/withoutgasshieldinTiNishapememoryalloyprecisepulseresistancebuttweldingusingtensilestrengthtest,XRD,SEMandTEMmeasures.Theoptimumweldingparametersobtaininghightensilestrengthweldedjointaregot.Ontheconditionofweldingpressmagnetingcurrent2Aandweldingheat75%,thejointstrengthisthehighest.ThisisimportantfortostudyotherpropertiesofTiNishapememoryalloyfurther.Theexperimentalresultsstatethatargongasshieldhavedifferenteffectsondifferentweldingparameters,lessonweldingpress,butgreatonweldingheat.Butexcessiveweldingpressandweldingheathavegreateffectsonjointtensilestrength.Toohighweldingheatcanproducethenewintermetalliccompound,thisintermetalliccompoundleadtodislocationdensitytoincreaseandformthepotentialcrackinitiation,whichcaneasilymakethejointfractureunderstresseffectanddecreasetheshapememoryratioofjointforhighdensitydislocationgroupsexistinginthetwinnedmartensite.

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简介：Thispaperstudiedthespotweldingstructureofultra-highstrengthsteel22MnB5.ANSYSsoftwarewasadoptedtosimulateitsstaticstrength;BS5400algorithmwasusedtocalculatethefatiguelife;andthegroupingmethodwasusedtotestthefatigueperformanceoftensileshearspotweldspecimens.Thesimulationresultswereingoodagreementwiththeexperimentalvalues.Basedonthevalidationofthesimulationmethod,influencesofdifferentstructuralparametersonstaticstrengthandfatiguelifewereexploredbyadoptingsinglefactor.Theresultsshowedthatwithintheselectedstructureparameterrange,increaseofthesheetthickness,nuggetdiameter,sheetwidthandoverlappinglengthcanleadtolongerfatiguelife.Besides,thefatiguelifeofspotweldtookonalinearrelationshipwiththeoverlappinglength,aDoseResprelationshipwiththesheetthickness,andasingleexponentialdecayrelationshipwiththesheetwidthandthenuggetdiameter.Moreover,inordertoestimatetheimpactfromvariousparametersonthefatiguelifeofthespecimens,theTaguchiorthogonaldesignmethodwasappliedinthesimulationdesign.Thesimulatingresultindicatedthatinfluenceofthesheetthicknessonfatiguelifewasthemostsignificant.Inaddition,theeffectsofnuggetdiameter,sheetwidthandoverlappinglengthonfatiguelifewerereducedinturn.

简介：Inthispaper,themicrostructureandhardnessofHG980Dheat-affectedzone(HAZ)atdifferentcoolingratet8/3werestudied,theimplantcriticalfracturestressunderthreediffusiblehydrogenconditionsweremeasured,andthehydrogen-inducedcracking(HIC)fractographofsteelHG980Dwereanalyzed.TheexperimentalresultsshowthatmartensiteexistsinHAZofHG980Dtillt8/3≥150s,thehardenquenchingtendencyofHG980Disgreater;Theimplantcriticalfracturestressisrelatedtodiffusiblehydrogencontentsignificantly,atlowhydrogenlevel,highrestraintstressisneededtonucleateHIC,thefractographismainlymicrovoidcoalescence,butathighhydrogenlevel,onlysmallrestraintstresscancauseHICoccurrence,thefractographismainlyquasicleavage.Itisveryimportanttochooseultra-lowhydrogenweldingconsumabletoweldsteelHG980Dtopreventhydrogen-inducedcracking.