钢制压力容器焊接工艺评定EN

本英文版为内部资料，仅供参考，以中文版为准。TheChineseversionofstandardshasprecedencetotheirEnglishtranslationswhichareonlyforinternalreference.中华人民共和国行业标准IndustrialStandardofthePeople'sRepublicofChinaJB4708—2000JB/T4709—2000JB4744—2000钢制压力容器焊接工艺评定钢制压力容器焊接规程钢制压力容器产品焊接试板的力学性能检验WeldingprocedurequalificationforsteelpressurevesselsWeldingspecificationforsteelpressurevesselsMechanicalpropertytestsofproductweldedtestcouponsforsteelpressurevesselsIssuance:15-08-2000Implementation:01-10-2000TheStateBureauofIndustryIssuedJointlyTheStateBureauofPetroleumandChemicalbyIndustryNoticefortheIssuanceofFourIndustrialStandardssuchas“WeldingProcedureQualificationforSteelPressureVessels”etc.No.:SMIB[2000]401Allsectorsinvolved,ThisistonotifythatinaccordancewiththeApprovalProceduresofPressureVesselsIndustrialStandardsasstipulatedbytheStateQuality&TechnologySupervisionBureau,thefourindustrialstandardssuchasWeldingProcedureQualificationforSteelPressureVesselsaretobereleasedwiththeindividualnumberanddesignationasfollows:Compulsivestandards:JB4708—2000WeldingProcedureQualificationforSteelPressureVessels，toreplaceJB4708—1992，JB4710—2000SteelTowerVessel，toreplaceJB4710—1992，JB4744—2000MechanicalPropertyTestsofProductWeldedTestCouponsforSteelPressureVessels，toreplaceGB150—1998AppendixE，Recommendedstandards:JB/T4709—2000WeldingSpecificationsforSteelPressureVessels，toreplaceJB/T4709—1992，TheabovestandardswillbeimplementedfromOctober1,2000.TheStateStandardTechnologyCommitteeofPressureVesselwillbewhollyresponsibleforthereleaseofthesestandardsinduetime.Regards,TheStateMachineryIndustrialBureauTheStatePetroleum&ChemicalIndustrialBureauAugust15,2000ContentsJB4708-2000Weldingprocedurequalificationforsteelpressurevessels……………4Preface…………………41.Scope………………52.Quotedstandards…………………53.Terminologies……………………64.Generalprinciples………………………75.Weldingprocedurequalificationregulationsforbuttandfilletweldingseam………86.Weldingprocedurequalificationregulationsforcorrosion-resistingbeadwelding…217.Testrequirementsandresultevaluation………………23AppendixA(appendixforstandard)Weldingprocedurequalificationforstainlesssteelcompoundsteel…………36AppendixB(appendixforprompts)Weldingprocedureinstructionandtherecommendedpatternsofweldingprocedurequalificationrecord…………38JB/T4709-2000WeldingspecificationforsteelpressurevesselsPreface1.Scope2.Quotedstandards3.Weldingmaterials4.Weldingprocedurequalificationandwelder5.Preparationbeforewelding6.Welding7.Postheating8.Postweldheattreatment9.Weldingseamre-repairing10,WeldinginspectionAppendixA(appendixforstandards)WeldingspecificationforstainlesssteelcompoundsteelAppendixB(appendixforprompts)RecommendedformofweldingprocedureinstructionJB4744-2000Mechanicalpropertytestsofproductweldedtestcouponsforsteelpressurevessels1.Scope2.Quotedstandards3.Symbols4.Themanufacturingrequirementsofproductweldedtestcoupons5.Testsamplepreparationofproductweldedtestcoupons6.Thetensiletest7.Thebendingtest8.Theimpacttest9.Re-testJB4708-2000Weldingprocedurequalificationforsteelpressurevessels中华人民共和国行业标准IndustrialStandardofthePeople'sRepublicofChinaJB4708-2000ToreplaceJB4708-1992钢制压力容器焊接工艺评定Weldingprocedurequalificationforsteelpressurevessels1.ScopeThisstandardstipulatesweldingprocedurequalificationregulations,testingmethodandqualifiedindexesforsteelpressurevessels.Thestandardissuitableforweldingprocedurequalificationofgaswelding,weldingrodelectricalarcwelding,submergedarcwelding,gasmetal-arcwelding,gastungsten-arcwelding,electroslagwelding,corrosion-resistingbeadwelding,etc.forsteelpressurevessels.2.QuotedstandardsThearticlesincludedinthefollowingstandardsbecomearticlesofthestandardbyquotation.Whenbeingpublished,allversionsofthestandardsarevalid.Sinceallstandardswillberevised,everyusershallseekthepossibilityofadoptingthelatestversionofthefollowingstandards.GB150-1998steelpressurevesselsGB/T228-1987metalstensiletestingmethodGB/T229-1994metalsimpacttestingmethodofxiabinotchGB/T232-1988metalsbendingtestingmethodGB713-1997steelplatesforboilerGB/T912-1989thinhot-rolledsteelplatesandsteelstripsofcarbonstructuralsteelandlow-alloystructuralsteelGB3087-1982seamlesssteelpipeforlowandmiddlepressureboilerGB/T3274-1988thickhot-rolledsteelplatesandsteelstripsofcarbonstructuralsteelandlow-alloystructuralsteelGB/T3280-1992cold-rolledstainlesssteelplatesGB3531-1996lowalloysteelplatesforlow-temperaturepressurevessels(includingtheNo.1modificationlist)GB/T4237-1992hot-rolledstainlesssteelplatesGB5310-1995seamlesssteelpipeforhigh-pressureboilerGB6479-1986seamlesssteelpipeforfertilizerequipmentGB6654-1996steelplatesforpressurevessels(includingtheNo.1andNo.2modificationlist)GB/T8163-1987seamlesssteelpipeforconveyingliquidsGB9948-1988seamlesssteelpipeforoilcrackingGB13296-1991seamlessstainlesssteelpipeforboiler’sheatexchangerGB/T14976-1994seamlessstainlesssteelpipeforconveyingliquidsJB4726-2000theforgedpiecesofcarbonsteelandlowalloysteelforpressurevesselsJB4727-2000theforgedpiecesoflowalloysteelforlow-temperaturepressurevesselsJB4728-2000thestainlesssteelforgedpiecesforpressurevesselsJB4730-1994thenon-destructivedetectionforpressurevessels3.TerminologiesThestandardadoptsthefollowingdefinitions.3.1WeldingprocedurequalificationTheexperimentalprocedureandresultevaluationcarriedoutforverifyingthecorrectnessofweldingpiece’sdraftedweldingprocedure.3.2WeldingprocedureinstructionTheweldingproceduredocumentsdrawnupforverificationexperiments,andpassingevaluationandtobeusedtoguidetheproduction.3.3ProcedurequalificationrecordTherecordreportingwhichmadearecordofaresultoftheverificationexperimentsindesignatedformsandevaluatedthecorrectnessofthedraftedweldingprocedure.3.4WeldedjointThejointpointwheretwoormorethantwopartswillbeweldedorhavebeenweldedtogether,wheninspectingjoint’sproperty,theinteractionofthedifferentsections,suchastheweldingseam,themoltenareaandtheheat-affectedzone,evenwithmaterials,shouldbetakenintoaccount.3.5WeldmentThepressurevesselsorotherpartsjoinedbywelding,theweldmentincludingbasemetalsandweldedjoints.3.6TestpieceTheweldmentforweldingprocedurequalificationtestmanufacturedaccordingtothepredeterminedweldingprocedure.Thetestpieceincludesbasemetalandweldedjoints.3.7PostweldheattreatmentTheheatingprocessthatcanchangethetissuesandpropertiesofweldedjointsortheirremainingstress.3.8LowertransformationtemperatureThephasechangetemperatureduringtheheatingprocesswherebeginstoformintoaustenite.3.9UppertransformationtemperatureThephasechangetemperatureduringtheheatingprocesswherefinishesausteniteforming.3.10TransversebendThebendbecauseoftheaxisoftheweldingseamisperpendiculartothelongitudinalaxisofthetestpiece.3.11LongitudinalbendThebendbecauseoftheaxisoftheweldingseamisparalleltothelongitudinalaxisofthetestpiece.3.12FacebendThebendbecauseofthetensilesurfaceofthetestpieceisthefrontsideoftheweldingseam.Thesurfacewhichhaslargerweldingseamwidthiscalledthefrontface;iftheweldingseamwidthsinbothsidesareequal,thenthefacewhosesurface-coveringweldingseamisfirstfinishedisthefrontface.3.13RootbendThebendbecauseofthetensilesurfaceofthetestpieceisthereversesideoftheweldingseam.3.14SidebendThebendbecauseofthetensilesurfaceofthetestpieceisthetransversesectionoftheweldingseam.4.Generalprinciples4.1Theweldingprocedurequalificationshouldbebasedonreliablesteelweldingpropertiesandfinishedbeforeweldingproducts.4.2Thegeneralprocessofweldingprocedurequalificationis:drawinguptheweldingprocedureinstruction,weldingtestpiecesandmanufacturingtestsamples,inspectingtestpiecesandsamples,measuringifweldedjointshavetherequiredutilityproperties,submittingweldingprocedurequalificationrecordandevaluatingtheweldingprocedureinstruction.Theweldingprocedurequalificationverifiesthecorrectnessofweldingproceduredrawnupbytheweldingunitandjudgesitscapability.4.3FortheT-typejointsandanglejoints,whosecrosssectionhavebeenweldedall,buttheirinteriordefectscannotbedetectedandthemanufacturingunithasnocapabilitytoensuretheweldingthroughout,thenthemodelingtestpieceshouldbemanufacturedforweldingprocedurequalificationandtheweldingshallbeallowedonlyafteraffirmationbydissectiontest.4.4Theequipmentandinstrumentsforweldingprocedurequalificationhavetobeinnormaloperatingcondition,steelsandweldingmaterialshavetobeconformedtotherelevantstandards,theunit’sskillfulweldercanoperatetheunit’sweldingequipmenttoweldtestpieces.5.Weldingprocedurequalificationregulationsforbuttandfilletweldingseam5.1Thebuttweldingtestpieceshouldbeadoptedwhencarryingoutthebuttweldingprocedurequalification.Thequalifiedbuttweldingprocedureissuitableforthefillet-weldingseam.Whenevaluatingtheweldingprocedureofno-pressurefilletweldingseam,thefilletweldingtestpiecescanbeonlyadopted.Thetestpiecesshapesareshowedinfigure1.a)Theplatebuttweldingtestpieceb)Thepipebuttweldingtestpiece，1，Thebuttweldingtestpiecesa)Theplatefilletweldingtestpieceb)Theplateandpipefilletweldingtestpiece，2，ThefilletweldingtestpiecesFigure1Thetestpiecesshapesforweldingprocedurequalification5.1.1Thequalifiedweldingprocedureoftheplatebuttweldingtestpiecesisapplicabletothepipebuttweldingseam,andviceversa.5.1.2Thequalifiedweldingprocedureoftheplateandpipefilletweldingtestpiecesisapplicabletotheplatefillet-weldingseam,andviceversa.5.2Theweldingprocedureelementsaredividedintotheimportantfactor,additionalfactorandminorfactor.5.2.1Theimportantfactorreferstotheweldingprocedurefactors,whichmayaffectweldedjointstensilestrengthandbendstrength.5.2.2Theadditionalfactorsrefertotheweldingprocedurefactors,whichmayaffectweldedjoints’impacttoughness.Iftheimpacttestisstipulated,theadditionalfactorshavetobeadded.5.2.3Theminorfactorsrefertotheweldingprocedurefactorsthathavenomarkedinfluenceonthestipulatedmechanicalproperties.5.3Qualificationregulations5.3.1Theweldingmethod5.3.1.1Re-qualificationisindispensableifchangingtheweldingmethod.5.3.1.2theimportant,additionalandminorfactorsoftheweldingprocedurequalificationforvariouskindsofweldingmethodsseetable1.a)Whenchanginganyimportantfactoritisnecessarytoevaluatetheweldingprocedurequalificationagain.b)Whenaddingorchanginganyadditionalfactor,thetestpiecesforadditionalimpactingtoughnesshavetobetestedaccordingtotheaddedorchangedadditionalfactors.c)Whenchangingminorfactors,re-qualificationoftheweldingprocedurequalificationisunnecessary,buttheweldingprocedureinstructionshouldbedraftedagain.5.3.1.3Thesameseamcanbequalifiedseparatelyaccordingtoeachweldingmethodorweldingprocedurewhenitisweldedbyadoptingthetwoormoreweldingmethods,orbytheweldingprocedurewhichhasdifferentimportantandadditionalfactors,anditcanalsobequalifiedcomprehensivelybyadoptingthetwoormoreweldingmethods,weldingproceduresandweldingpieces.Whenbeingappliedtotheweldmentaftercomprehensivequalificationqualification,oneormoreweldingmethods,weldingprocedurecanbeadopted,buttheirimportantandadditionalfactorsshouldberemainedunchanging,accordingtotherelevantregulationsforeachweldingmethodorweldingproceduredeterminestheeffectiverangeissuitableforweldmentthickness.5.3.2BasemetalsThestandardshallclassforthebasemetalsclassificationandgroupsaccordingtothechemicalcomposition,mechanicalpropertiesandweldingproperties(seetable2).5.3.2.1Groupingregulationsa)Whentheimportantandadditionalfactorsremainunchanged,thequalifiedweldingprocedureofonegradebasemetalmaybesuitablefortheothergradebasemetalsinthesamegroup.b)ThequalificationforthebasemetalsingroupVI-2issuitableforthebasemetalsingroupII-1.c)Inthesameclassificationnumber,thequalificationforbasemetalswithhighergroupnumberissuitablefortheweldedjointsmadeofthebasemetalsinthisgroupandthebasemetalswithlowergroupnumber.d)Apartfromthecircumferencesthatisregulatedinb)andc),ifthereischangeinbasemetalsgroupnumber,therehavetohaveare-qualification.5.3.2.2ClassificationqualificationregulationsForweldedjointsmadefrombasemetalswithdifferentclassification,evenifeachbasemetalhasbeenqualified,re-qualificationfortheweldedjointsisnecessary.ButthequalificationoftheIIclassification(orVI-1,VI-2group)basemetalwiththesamesteelgradeissuitablefortheweldedjointsfromthesameclassification(orthesamegroup)basemetalandtheIclassificationbasemetal.5.3.2.3Qualificationregulationsofthesteelgradesnotincludingintable2a)ThegradeofsteelincludedinNationalStandardsorIndustrialStandardsshouldbeclassifiedintotheircorrespondingclassificationsandgroupsorintonewclassificationsandgroupsaccordingtotheirchemicalcomposition,mechanicalpropertiesandweldingproperties.AndtheweldingprocedurequalificationshouldbecarriedoutforthesteelgradesthatarenotincludedinNationalStandardsorIndustrialStandards.b)Fortheforeignsteels,theweldingprocedurequalificationshouldbecarriedouttoeachsteelgrade(namedasitsNationalstandardregulation)onitsfirstapplication.Ifitsweldingpropertieshavebeenknownanditschemicalcomposition,mechanicalpropertiesareequivalenttothatofonesteelgradeintable2,andtheweldingprocedurequalificationforthatsteelcodehasbeenfinished,thentheweldingprocedurequalificationforthisforeignsteelcanbeexempted.Itcanbeclassifiedintotheclassificationandgroupofthatsteelgradeintheunitstechnologydocuments.5.3.3Post-weldingheattreatment5.3.3.1Classificationsofthepost-weldingheattreatment5.3.3.1.1ThebasemetalswithclassificationNo.VIIisdividedinto:a，Donotcarryoutpost-weldingheattreatment;b，Carryingoutthesolidsolutiontreatmentorstabilizationheattreatmentafterwelding.5.3.3.1.2ThebasemetalsexceptclassificationNoVIIaredividedinto:a，Donotcarryoutpost-weldingheattreatment;b)Carryingoutpost-weldingheattreatmentwhentemperatureislowerthanthelowertransformationtemperature;c)Carryingoutthepostweldingheattreatmentwhentemperatureishigherthantheuppertransformationtemperature(forexample:normalizing);d)Carryingoutthepostweldingheattreatmentfirstlyintemperaturehigherthantheuppertransformationtemperature,thenintemperaturelowerthanthelowertransformationtemperature,(e.g.temperingafternormalizingorquenching);e)Carryingoutthepostweldingheattreatmentbetweentheupperandlowertransformationtemperature.5.3.3.2Weldingprocedurere-qualificationisnecessaryifchangingthekindofpost-weldingheattreatment.5.3.3.3Whentheimpacttestisspecified,Theweldingprocedurequalificationisneededifchangingtherangeoftemperatureandthetimeofthepost-weldingheattreatment.Butthegasweldingistheexception.Thepost-weldingheattreatmentofthetestpiecesshouldbegenerallysameasthatoftheweldedpiecesinthemanufacture,theheatingtemperatureoftestpiecesshouldnotviolatetheregulationsofthecorrespondingstandardsortechnologydocuments.Whencarryingoutthepost-weldingheattreatmentwiththetemperaturebelowthelowertransformationtemperature,thetestpiecesholdingtimeshouldbenolessthan80%oftheweldingpiecesamountedholdingtimeduringitsmanufacturingprocess.5.3.4TestpiecesthicknessandweldingpiecesthicknessTheeffectiveextentofweldingpiecesthicknessforwhichthequalifiedweldingprocedureofbuttweldingtestpiecesissuitable:followingtheregulationsoftable3and4ifthebasemetalsofthetestpiecesareinIV-2groupandthestrength-typelowalloysteelwhoselowerlimitofthestandardtensilestrengtharelargerthan540MPa;Others,thesteelsshouldfollowtheregulationoftable5and65.3.4.1Fortheelectric-arcweldingofwelding-rod,submerged-arcwelding,gastungsten-arcweldingandgasmetal-arcwelding,iftheimpacttestisspecifiedforweldingpieces,inthecaseof?8mm,theminimumoftheTeffectiveextentoftheweldingpiecesbasemetalsthicknessaftertestpieceshadbeenassessedasqualificationshouldallbe0.75T,itwouldbetreatedaccordingtotheoriginalregulationsifthetestpieceshavebeenprocessedbypost-weldingheattreatmentintemperatureabovetheuppertransformationtemperatureortheaustenitebasemetalshavebeenprocessedbysolidsolutiontreatmentafterwelding.5.3.4.2Iftheweldingpiecesarewithinthecircumferenceoftable7,themaximumoftheeffectiveextentofweldingpiecesbasemetalsthicknessshouldfollowtheregulationsintable7aftertestpieceshadbeenassessedasqualification.Table3TheregulationonthetestpiecesbasemetalsthicknessandweldingpiecesbasemetalsthicknessmmTheeffectiveextentsuitableforweldingpiecesbasemetalsThetestpiecesbasethicknessmetalsthicknessTMinimumMaximumT<1.52TT1.5?T<81.52Tandnothickerthan12T?80.75T1.5TTable4TheregulationsonthetestpiecesweldingseammetalsthicknessandweldingpiecesweldingseammetalsthicknessmmTheeffectiveextentsuitableforweldingpiecesweldingThetestpiecesweldingseammetalthicknessseammetalsthicknesstMinimumMaximum<1.5Nolimitation2tt1.5?t<8Nolimitation2t,Nothickerthan12t?8Nolimitation1.5tNote:trepresentsthicknessoftheweldedwelding-seammetalbythesameweldingmethod(orweldingprocedure).Table5Theregulationonthetestpiecesthicknessandweldingpiecesthickness(carryingoutthetestpiecesmechanicalpropertiestestandtransversebendingtest)mmThetestpiecesTheeffectiveextentsuitableforTheeffectiveextentsuitableforbasemetalsweldingpiecesbasemetalsweldingpiecesweldingseammetalthicknessTthicknessthicknessMinimumMaximumMinimumMaximum<1.5T2TNolimitation2t1.5?T<101.52TNolimitation2t10<T<3852TNolimitation2t?385200*Nolimitation2t(t<20)*?385200*Nolimitation200(t?20)*Limitedtomulti-runweldingofwelding-rodelectricarcwelding,submerged-arcwelding,gastungsten-arcweldingandgasmetal-arcweldingTable6Theregulationonthetestpiecesthicknessandweldingpiecesthickness(carryingoutthetestpiecesmechanicalpropertiestestandlongitudinalbendingtest)mmTheeffectiveextentsuitableforTheeffectiveextentsuitableforThetestpiecesweldingpiecesbasemetalsweldingpiecesweldingseambasemetalsthicknessmetalthicknessthicknessTMinimumMaximumMinimumMaximum<1.5T2TNolimitation2t1.5?T?101.52TNolimitation2t>1052TNolimitation2tTable7thetestpiecesthicknessandtheregulationonweldingpiecesthicknessinspecialconditionmmTheeffectiveextentsuitableforweldingpiecesbasemetalsTheThetestpiecesthicknessserialbasemetalsTheweldingpiecesNo.thicknessconditionMinimuMaximumm1Whenthewelding-rodelectric-arcwelding,Qualifiedaccordingsubmerged-arcwelding,tothequalificationgastungsten-arcweldingresultsofothersandgasmetal-arcwelding?13*weldingproceduresareusedastherootforweldingseamswelding,itcanbecontinualfilling.assessedsingularly,atthemoment2Thepartbuttwelding?38*Nolimitationpieceswhichwerewelded3Repairingwelding,?38*Nolimitationmake-upwelding4Nospecifyingtheimpacttestforthebase(Thebasemetal’smetalwhosethicknessofthe*Theunequal-thicknessclassificationisthickeredge)buttweldingtestpiecesVIINolimitationshouldbeassessedbythe?6equal-thicknessbuttweldingtestpieces(Thebasemetal’sExceptthebasethicknessofthemetalwhose*thickeredge)classificationisVII,?38Nolimitation*Accordingtothetestpiecesorweldingpiecescondition,followingthecorrespondingregulationsintables3,5,6andarticle5.3.4.1.5.3.4.3Ifthetestpiecesconformtotheweldingconditionsintable8,themaximumthicknesssuitableforweldingpiecesaftertestpieceshavebeenassessedasqualificationarespecifiedintable8.Table8.RegulationsonthetestpiecesthicknessandweldingpiecesthicknessinspecialweldingconditionmmTheThemaximumthicknesssuitableThetestpiecesweldingconditionserialforweldingpiecesNoBasemetalWeldingseammetal1Exceptgaswelding,thetestpiecesbeingprocessedbypostweldingheat1.1T*treatmentovertheuppertransformationtemperature.2Whentestpiecesaresingle-runormulti-runwelding,ifthethicknessofany1.1T*oneofitsweldingbeadisthickerthan13mm3GasweldingT*4Electroslagwelding1.1T*5Whenthetestpiecesthicknessisthickerthan150mm,andadoptingmulti-runweldingofwelding-rodelectric-arcwelding,submerged-arcwelding,gas1.33T1.33ttungsten-arcweldingandgasmetal-arcwelding(excepttheshort-circuitedtransition)6Whenthetestpiecesthicknessisthinnerthan13mm,andadoptinggasmetal-arc1.1T*weldingwithshort-circuitedtransition7Whenthetestpiecesweldingseammetal’sthicknessisthinnerthan13mm,*1.1tandadoptinggasmetal-arcweldingwithshort-circuitedtransition*Accordingtothetestpiecesorweldingpiecescondition,followingthecorrespondingregulationsintables4,5,6andarticle5.3.4.1.5.3.4.4Thereisnolimitationontheweldingpiecesthicknesseffectiveextentwhenthequalifiedweldingprocedureforbuttweldingtestpiecesisappliedtothefilletweldingpieces;Thereisnolimitationontheweldingpiecesthickness’effectiveextentwhenthequalifiedweldingprocedureforfilletweldingtestpiecesisappliedtothenon-pressurefilletweldingpieces.5.3.4.5Afterfinishingthecompoundqualification,theeffectiveextentoftheweldingpiecesbasemetal’sthicknessshouldbedeterminedbysingleweldingmethods(orweldingprocedure)qualification.6.Weldingprocedurequalificationregulationsforcorrosion-resistingbeadwelding6.1Re-qualificationisindispensableifchangingthebeadweldingmethod.6.2IfthethicknessofthetestpiecesbaselayerTislessthan25mm,thequalifiedweldingprocedureissuitableforweldingpieceswhosebaseisnolessthanorequalto,Ifthetestpiecesthicknesslayer’sthicknessTTTTisnolessthan25mm,thequalifiedweldingprocedureissuitableforweldingpieceswhosebaselayer’sthicknessisnolessthanorequalto25mmtoo.6.3Theweldingconditionsforre-qualificationofthecorrosion-resistingbeadweldingseetable9.Table9.Weldingconditionsforre-qualificationofthecorrosion-resistingbeadweldingClassificationThebeadweldingconditionsGasweldingWeldingrodelectricarcweldingSubmergedarcweldingThebeadThebeadweldinglayer’sthicknessisweldingthinnerthanthequalifiedminimumGasmetal-arcwelding—?????layer’sthicknessGastungsten-arcweldingthicknessChangingtheclassificationofthebaseElectroslagwelding??????layer’smetalBasemetalThethicknessofthebaselayersteelis??????beyondtheregulationof6.2Changingweldingrod’sspecifications(onlyconsideringthelater—?————twodigitsofitsclassification)Changingweldingrod’sdiameterwhencarryingourthefirstlayerbead—?————weldingAddingorcancelingadditionalfiller——??—?metalFillermetalChangingthesteelgradeofthewelding——????wire(orsteelstrip)Changingtheweldingflux’sspecificationorthemixingproportion——?——?ofthemixingweldingfluxChangingthesolidweldingwiretotheshieldedcoredweldingwire,orvice———??—versaClassificationThebeadweldingconditionsGasweldingWeldingrodelectricarcweldingSubmergedarcweldingExceptthequalificationfortransversewelding,erectweldingoroverheadGasmetal-arcweldingWeldingweldingpositionissuitablefortheflat—?—??—positionGastungsten-arcweldingweldingposition,changingthequalifiedweldingpositionElectroslagweldingThepre-heatingtemperatureis50?lowerthanthequalifiedvalueorisoverPre-heating—?????themaximumlayertemperatureofthequalificationrecordTheheatChangingtheclassificationoftheheattreatmenttreatmentofpostwelding,orthetotalofincreasedtimeforthepostweldingheat—?????post-weldintreatmentexceedsthequalifiedtimebyg25%.Changingtheclassificationofshieldedgas,changingthemixingproportionofGas———??—themixingshieldedgas,cancelingshieldedgas.Changingcurrent’sclassificationor—?????polarityElectricityTheincreasedlinearpowerorthecharacteristivolumeofweldedmetalonperunitcs—?????lengthweldingbeadhasexceededtheassessedqualificationvalueby10%TheChangingthemulti-layerbeadweldingtechnologytosingle–layerbeadwelding,or—?????measuresvice-versa.Cancelingthemagneticfieldcontrolof——?——?themoltenweldingpoolChangingthequantityoftheelectrodes——??—?onthesamemoltenpoolAddingorcancelingelectrodes’——????oscillationNote:1.Thesymbol“?”meansthattheweldingmethodisthere-assessedweldingmethod2.Thesymbol“*”meansthequalifiedbeadweldingprocedureforbaselayer’ssteelgradein?-1groupiss