简介：Keyholeplasmaarcweldingexperimentsareconductedtomeasuretheweldgeometryandpenetrationatdifferentmomentsduringtheinitialphasefromignitingarctoquasi-steadystate.Indirectinformationonkeyholeformationandevolutioninplasmaarcweldingcanbeextractedbasedontheweldmacrophotographatcrosssection.Ithaslaidfoundationtoverifythemathematicalmodelsofkeyholeplasmaarcwelding.

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简介：Anewkindofcontrolsystemforkeyholeplasmaarcwelding(K-PAW)wasdevelopedbasedonthecomputerandtheGraphicsLanguage-LabVIEW.Itcansetandoutputtherequiredcurrentwaveformswithdesireddecreasingslopessothatthecorresponding'openingandclosing'ofkeyholecanoccurperiodically.Withthiscontrolstrategyofweldingcurrentwaveforms,theworkpieceisfullypenetratedwhilenoburn-throughoccurs.Keyholeplasmaarcweldingexperimentswereconductedtoverifythestabilityandreliabilityofthedevelopedsystem.

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简介：Metaltransferisanimportantphenomenoninmetalinertgas(MIG)arcweldingwithlongitudinalalternatingmagneticfield.Itisofgreatsignificancetoobservethemetaltransfermodesunderdifferentexcitatorycurrentsandfrequencies.However,itisverydifficulttoviewthemetaltransferprocessdirectlyduringwelding,duetothestronginterferencefromthearclight.Toobtaintherelationshipbetweenthemetaltransfermodesandthedifferentmagneticfields,ahigh-speedvideocamerawasusedtoacquiretheimagesofglobules.Differentmetaltransfermodesundertheconditionsofdifferentmagneticfieldsandweldingparameterswerestudied.Theexperimentshowsclearimagesofdroplettransferaswellasinfluenceoflongitudinalmagneticfieldonbothmetaltransferandglobuleshape.

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简介：Alotofexperimentalmethodshavebeenbroughtforthtoassessthedynamiccharacterofthearcweldingpowersource,butuptonow,thisissuehasnotbeensolvedverywell.Inthispaper,basedonthefuzzylogicreasoningmethod,adynamiccharacterassessingmodelforthearcweldingpowersourcewasestablishedandusedtoanalyzethedynamiccharacteroftheweldingpowersource.Threedifferenttypesofweldingmachinehavebeentested,andthecharacteristicinformationoftheelectricalsignalssuchasre-strikingarcvoltage,lowweldingcurrentandsoonoftheweldingprocesswereextractedaccuratelybyusingaself-developedweldingdynamicarcwaveletanalyzer.Theexperimentalresultsindicatethatthismodelcanbeusedasanewassessingmethodforthedynamiccharacterofthearcweldingpowersource.

简介：ThesoftswitchingareweldinginverterreducesswitchinglossesandimprovesoperatingenvitonmentofdevicesbyusingZero-Voltage-Transition(ZVT)technique.Step-by-stepanalysisofeachtimingintervalandtheassociatingvoltageandcurrentwaveformsareincludedfortheFull-BridgeZero-Voltage-SwitchedPWMcomerter,Numerousdesignequationssupportingthephase-shiftedsoftswitchingtechniquearehighlighte.

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简介：Accordingtothespecificationofsuperalloy-stainlesssteelarcbrazingandcharacteristicofthebasemetal,abestfillermetalwhichhasrelativelowermeltingpoint,nicewettability,goodweldforming,andadequateshearstrengthwasresearched.TheexperimentresultsshowthatwettabilityofCuFeMnonthestainlesssteelisverypoor,concomitantwithamassofpurplesootduringtheweldingwhichdeterioratestheworkingcondition.CuSiMnhasthebestwettabilityonboththesuperalloyandstainlesssteel,butthereremainsalotofpitandslagonthesurfaceoftheweldbead.Copper-basedsolderhasthehighestmeltingpointanditswettabilityandclearancefillabilityareweakerthanCuSi3.WettabilityandclearancefillabilityoftheCuSi3arethebestinallthecandidatefillermetals,anditsweldissmoothnessandhashighershearstrength.Foritscomprehensiveability,CuSi3isselectedasthefinalfillermetal.

简介：Full-bridgeZero-Voltage-SwitchPWMconvertercombinesadvantagesofthePWMcontroltechniqueandresonanttechnique.However,FullZVSisachievedonlyunderlargeloadcurrentbecauseresonanttankofthiscircuitismadeupoftheparasiticcapacitanceofthepowersemiconductorsandtheleakageinductorofthetransformerprimary.Inthispapertwosaturableinductorsasmagneticswitchesareaddedtosecondary,sooutputinductorisalwaysreflectedtoprimaryandassistsresonanttransition.FullZVSisachievedunderlowerloadcurrent.Theabove-mentionedinvestigatedresultsarevalidatedbythecomputerizedsimulationandhardwarecircuitexperiment.

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简介：Adigitalarcweldingpowersupplywasdesignedwiththeadvancedreducedinstructionsetcomputermachine(ARM)andembeddedreal-timemulti-taskoperatingsystemmicroC/OS-Ⅱ.TheARM,withitspowerfulcalculatingspeedandcompleteperipheralequipments,isverysuitabletoworkasthecontrollerofthedigitalpowersupply.ThemicroC/OS-ⅡtransplantedinARM,helpstoimprovetherespondentspeedagainstvariousweldingsignals,aswellasthereliabilityofthecontrollingsoftware.Theweldingprocessconsistsofninetasks.Thetasksofgreatsignificanceonreliabilityofthewelder,forexample,theA/Dconversionofcurrentandvoltage,enjoytoppriority.Toavoidsimultaneous-sharingonA/DconverterandLCDmodule,twosemaphoresareintroducedintoensurethesmoothperformanceoftheweldingpowersupply.Provenbyexperiments,theARMandthemicroC/OS-Ⅱcangreatlyimproveboththerespondentspeedandthereliabilityofthedigitalwelder.

简介：OnthebasisOftheYoung-LaplaceEquationthatdescribesthepressuredifferencebetweeneachsideofacurvedliquidsurface,astaticequilibriummodelisestablishedtodescribethesurfaceshapeoftheweldbead.Thegeo-metricalmodelforthemoltenpoolisincluded,whichisessentialtoexplaintheundercutphenomenonduringhighspeedbead-on-platewelding.Theresultsgotfromaniterationalgorithmshowthatitistheforcebalanceontheliquidmixtureofthedepositedmetalandthedepositedmetalandthemoltenbasemetalandthemoltenbasemetalthatcausestheundercut.Somefactorsandtheireffectsarealsoana-lyzed.