简介：Aplasmaarcwelding(PAW)-tungsteninertgas(TIG)hybridweldingprocessisproposed.AndthispaperinvestigatedthemicrostructureandpropertiesofpurenickelN6jointsbyPAW-TIGhybridwelding.ComparedwiththeconventionalPAWmethod,thecharacteristicofPAW-TIGweldingprocessisthatthereisnointeractionbetweenthetwoarcs.TheadditionofTIGcanenhancetheintrinsichigh-efficiencypeculiarityandthestabilityofthekeyholestatusofPAW.ThejointsmadeusingPAWandPAW-TIG,respectively,weresubjectedtomicrostructuralevaluationsandtensiletestingsoastoanalyzetheeffectofTIGarcenergyonthemicrostructureandmechanicalpropertiesofthesejoints.Theresultsofthisinvestigationindicatethatsignificantgraincoarseningwasobservedintheweldmetal(WM)andheataffectedzone(HAZ)anditisfoundthattheextentofgraincoarseningincreasedwiththeadditionofTIGarc.Andthemicrostructureinhybridjoint,withwiderweldwidthandthesmoothsurface,iscoarserthaninPAWjoint.Furthermore,themicrohardnessandultimatetensilestrength(UTS)ofhybridjointisslightlylowerthanthatofPAWjoint.ThefractographobservationshowsthatthefracturingmechanismofPAWjointsductile,whilethehybridweldingjointsexistsasbrittle-ductilefracturemode.Theoutcomeofthisworkshowsthatintheconditionofsamedepositedrate,TIGarcpost-weldheattreatmentcanimprovetheweldingefficiencyandweldingspeed.TheproposedPAW-TIGhybridweldingprocessisdemonstratedtobesuitableforweldingnickelanditsalloysinindustryapplication.

简介：穿孔等离子弧焊接过程中,小孔的形状和尺寸决定着热源热流密度的分布和温度场的分布,从而影响着焊接过程的稳定性和焊接质量。本文利用四阶Runge-Kutta法求解在小孔壁上的力的控制方程组。数据表明模拟结果与试验观测现象基本吻合。

简介：Manualmonitoringandseamtrackingthroughwatchingweldpoolimagesinreal-time,bynakedeyesorbyindustrialTV,areexperience-depended,subjective,laborintensive,andsometimesbiased.Soitisnecessarytorealizetheautomationofcomputer-aidedseamtracking.APAW(plasmaarcwelding)seamtrackingsystemwasdeveloped,whichsensesthemoltenpoolandtheseaminoneframebyavisionsensor,andthendetectstheseamdeviationtoadjusttheworkpiecemotionadaptivelytotheseampositionsensedbyvisionsensor.Anovelmoltenpoolareaimage-processingalgorithmbasedonmachinevisionwasproposed.Thealgorithmprocesseseachimageatthespeedof20frames/secondinreal-timetoextractthreefeaturevariablestogettheseamdeviation.Itisprovedexperimentallythatthealgorithmisveryfastandeffective.Issuesrelatedtothealgorithmarealsodiscussed.

简介：Basedontheoriesofheattransfer,physicalmetallurgyandhydro-mechanical,inordertoanalyzetheeffectofweldingparametersonspeciesanddistributionofreinforcingphasesvisuallyandlegibly,finiteelementsoftwareANSYSwasusedtosimulatetransienttemperaturefieldforSiC_p/AIin“in-situ”weld-alloying/plasmaarcwelding.Theresultsshowthatthecalculatedresultsapproximatelyagreedwiththeexperimentalmeasuredresults.Sothemodelisbasicallycorrectandcredible.Basedonthenumericalsolutionsandexperimentalresults,effectoftemperaturefieldindifferentweldingprocessparameters(weldingcurrent,weldingvelocity)onspeciesanddistributionofreinforcingphasesisanalyzed.Theresultsshowthatadjustingandoptimizingtemperaturefieldappropriatelyisaneffectivemethodtoobtainweldedjointwithbettermicrostructureandproperty.