电焊工技师、高级技师理论考试题目（welder technician and senior technician in theory exam）

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电焊工技师、高级技师理论考试题目（Weldertechnicianandseniortechnicianintheoryexam）WeldertechnicianandseniortechnicianintheoryexamAbriefanswer:1.Howmanykindsofweldmarkingmethodsarethere?Whatarethey?Answer:therearetwokinds:Dimensioninganddiagramming2,heattreatmentofsteelcanberoughlydividedintothosebasictypesAnswer:theheattreatmentofsteelisdividedinto1,commonheattreatment(annealing,normalizing,quenchingandtempering)2surfaceheattreatment(1)surfacequenching(2)chemicalheattreatment(carburizing,nitriding,carbonitriding)3,accordingtotherelevantsafetytechnicalstandards,whatarethesafetyvoltagesforaspecificoperatingenvironment?Answer:1,forrelativelydryandelectricshockdangerousenvironment,thesafetyvoltageis36V.2,fordampandelectricshock,dangerousenvironment,the safetyvoltageis12V.3,forunderwaterorotherelectricshockcausedbyserioustwoaccidentenvironment,thesafetyvoltageis3V,Thestandardalsospecifiesthesafevoltageisnotusedautotransformerforportableworklamporcontrolbutton,becausetheautotransformeroutputvoltageandlowvoltagenetworkarenotisolated,sothereisnosecurity.4,whataretheadvantagesoffluxcoredwire?Answer:1,weldingprocessperformanceisgood.2,depositionfast,highproductionefficiency.3,alloysystemadjustment,theapplicabilityofsteel,4,lowenergyconsumption,5,comprehensivecostislow,5,commerciallyavailableCO2gas,suchashighwatercontent,whatmeasurescanbetakentoreducemoisture?Answer:1,thenewgasbottleupsidedownfor2hours,Openthevalve,drainthewaterwhichisdepositedinthelowerpart,andpourthegascylinderdownafterthewaterisfinished. 2.Useairfor2-3minutesbeforeusebecausetheupperairusuallycontainsmoreairandwater.3.HighpressuredryersandlowpressuredryersareinstalledinthegaspathtofurtherreducemoistureintheCo2.Generallyusesilicagelordehydratedcoppersulfateasdesiccant,canberepeateddrying,afterrepeateduseofwater.4,whenthegaspressureinthecylinderfallsbelow0.98MPa,nolongeruse.Atthispoint,whentheliquidCo2hasevaporated,thegaspressuredecreaseswiththegasconsumption,therelativepressureofwaterincreases,andthevolatilecontentincreases.Ifcontinuetouse,theweldmetalwillproduceairholes.6,accordingtothedischargecurrentsize,thegasdischargeisdividedintoseveralformsWhatisit?Answer:threeforms:darkdischarge,glowdischarge,arcdischarge.7,whataresomeoftheMIGwelding?Answer:highefficiency,deepmelting,suitableforthinwallpartswelding,weldingspeed,deformation,smokeless,weldmetalhydrogencontentislow,brightarcwelding,easytoachieveallpositionwelding.8,whataretheadvantagesofsubmergedarcwelding?Answer:highproductionefficiency,goodweldingqualityand goodworkingconditions.9.Whatarethecausesofstressconcentrationinwelding?Answer:weldingprocessdefects,unreasonableweldshape,designunreasonableweldjoints.10,thefactorsaffectingweldingdeformation?Answer:thelocationoftheweld,therigidityoftheweldingstructure,theassemblyandweldingsequenceoftheweldingstructure,theweldingmethod,theweldingdirectionandthecoefficientofmateriallinearexpansion.Two.Questionsandanswers:1,weldingroddryingshouldpayattentiontowhatmatters?Answer:1,whendryingelectrode,forbidtoputtheelectrodesuddenlyintothehightemperaturestove,orsuddenlytakeoutcooling,preventtheelectrodetoquench,suddenlyheatandproducemedicineskincrackphenomenon.Theweldingmaterial2,eachdryingboxonlyonceinagrade,inthesamedryingconditions,materialsandimplementstheseparationbetweenmarkedweldingconditionsofdifferentgrades,canbethesamedryingboxweldingmaterialintodifferentgrades,dryinguponlyaweldingelectrode,overlappingthreelayers.Toavoidtheunevenheatinganddryingwhentheelectrodeisnoteasytoremovemoisture. 3,thedryingelectrodeshouldbeinthetemperaturedroppedto100-150degrees,fromthedryingboxintotheincubatorstorage,thetemperatureoftheincubatoriscontrolledwithintherangeof100-150degrees.4,weldingelectrode,fluxshouldberecordedwhendrying.5,bakingovenisnotallowedtobakeotherthings.2.Thecharacteristicsoftheweldingthermalprocessdeterminewhatarethemaincharacteristicsoftheweldingprocess?Answer:1,thearcofhightemperatureandlargetemperaturegradient,weldingarctemperatureupto5000-8000DEGC,themetalevaporation,gasarcaroundthedifferentdegreesofdecompositionofgasatomsandions,dissolvedinliquidmetal,thetemperaturedropscannotprecipitate,resultinginstomatal.Atthesametime,themoltenpoolundertheactionofhightemperatureissurroundedbynormaltemperaturemetal,andthetemperaturegradientisgreat.Thisisthemainfactorofweldingstressanddeformation.2,thereactiontimeisshort,thatis,themoltenpoolhasashorttime,themetallurgicalreactionoftheweldmetalisnotenough,andthemicrostructureisquitedifferent.3,theweldpoolsizeissmall,andthereactioncontactareaislarge,thefronthasbeendescribed,withelectrodeweldingasanexample,Thequalityoftheweldpoolisonly3-5grams,andexcessive tomoltendropletsurfaceareaof1000-10000csquaremeters/kg,1000timeslargerthanthesteel,whichmakesthemetallurgicalreactionfierce,andhavestrongmixingeffect.4.Thereactionofmoltenpoolismoving.Whenwelding,themoltenpoolmovescontinuously,andthereactionmaterialchangesconstantly,whichmakestheweldingmetallurgicalreactionmorecomplicated.3,heattreatmentisdividedintoseveralkinds?Whatisthepurpose?Answer:heattreatmenthasannealing,normalizing,quenching,temperingandsoonAnnealing:heatingtheworkpiecetoacriticalpoint(Ac1orAc3)aboveacertaintemperatureforacertainperiodoftime(holdingit)andthenperformingaslowcooling(coolingwiththefurnace).ThisprocessiscalledannealingThepurposeofannealing:1.reducehardness,easytocuttheworkpiece2.improvethestructureandmechanicalpropertiesofmaterials3.improvetheorganizationalstructureandprepareforfuturequenching4.eliminateinternalstress 5.gettinycrystalsNormalizing:heattheworkpiecetoAc3ormorethan30-50Acm.Afterheatpreservation,removeheatfromthefurnaceandcoolitintheair.(normalizingcoolingismuchfasterthanannealing)Afternormalizing,thestrengthandhardnessarehigherthanthoseofannealing,theplasticityisalittlelower,thepearlitequantityincreases,andtheimprovedstructureensureshighermechanicalproperties,becauseofthecoolinginair,theproductivityishighQuenchingistheworkpieceheatedtothecriticalpoint(Ac3orAc1)above,afterheatpreservation,rapidcoolingtoobtainmartensiticmicrostructure(austenitealsohaveacertainamountof),theheattreatmentoperationcalledquenchingsteelafterquenching.Prominentfeaturesintheperformanceisofhighhardnessandplasticityisverylow.Quenchingpurposes:1.increasethehardnessandwearresistanceofthesteelworkpiece2.byquenchingandsubsequentmediumtemperatureorhightemperaturetemperingcanmaketheworkpiecegetgoodcomprehensiveperformanceTempering:heatingtheworkpieceisquenchedtobelowAc1temperature,holdingtime,andthencoolingdowninthewater, oilorair.(temperingisdoneimmediatelyafterquenching,temperingtempering,temperingandtempering)Thepurposeoftemperingistoreduceoreliminatetheinternalstresscausedbythehardeningoftheworkpieceandtoimprovetheplasticityandtoughnessinordertoobtainthedesiredandpossiblemechanicalpropertiesoftheworkpieceinuse4,theroleofweldingfluxinweldingprocessisdiscussedAnswer:welding,weldingfluxistoensurethequalityofthemainfactors,ithasseveralfunctions;(1)thefluxismeltedonthemoltenmetalsurfacetoprotectthemoltenpoolandpreventtheharmfulgasesfromattackingintheair.(2)thefluxhasthefunctionofdeoxidationandalloying,andwiththeweldingwire,theweldmetalgetstherequiredchemicalcompositionandmechanicalproperties.(3)theweldiswellformed.(4)slowdownthecoolingrateofmoltenmetal,reduceporosity,slaginclusionandotherdefects.(5)preventspatter,reducelossandincreasecoefficientoftie.5.ShallwepayattentiontothemattersoftheuseandmaintenanceofACarcweldingmachine? Answer:(1)shouldbeinaccordancewiththeweldingmachineratedweldingcurrentandloadduration,donotoverload.(2)thewelderisnotallowedtoshort-circuitforalongtime.(3)theregulatingcurrentshouldbeoperatedwithoutload.(4)alwayscheckwirecontacts,fuses,grounding,regulatingmechanism,etc.,andtrytobeingoodcondition.(5)keeptheweldingmachineclean,dryandventilated,preventdustandrainfrominvading.(6)thepositionissteadyandthepowersupplyiscutoffaftertheworkisfinished.(7)theweldershouldberegularlycheckedandrepaired.6.DescribethesafeoperationtechnologyofmanualarcweldingAnswer:(1)payattentiontono-loadvoltagenotexceedtheratedvalue,both:AC60V,DC90V(2)theweldingslagshouldbeprotectedwithgoggles(3)theconstructionareashouldbeequippedwithshieldboardtopreventthelightfromradiation(4)withelectrodeholdershallnottakeplace (5)donotthrowtheweldingroddirectly;itshouldbepiledupcentrally.Payspecialattentiontofireprevention(6)whenweldingnon-ferrousmetals,galvanizedpipesoralloys,masksshouldbetakentopreventZincOxidefrominhalingthebody(7)theendoftheworkshouldbeclearedofspace,tools,etc.,andcutoffthepowersupply(8)theshellofthewelderisgrounded(9)theweldingpieceneedstheplantashtokeepwarm,whencold,shouldpayattentiontothethingaround,preventfire(10)disconnectthepowersupplyfromthemobilewelderorexchangeconnection(11)theweldinginthecontainershallbeattendedbypeopleoutside(12)weldingandfillingofflammableandexplosivemediacontainersorpipes,toreplacethequalified,openallthecovers7,whatarethedangersofbrittlefracture?Answer:asbrittlefracturehasthecharacteristicsofsuddenoccurrence,lackofdiscoveryandprevention,onceithappens,theconsequencesareveryserious,whichnotonlycausesignificanteconomiclosses,butalsoendangerpeople'slife safety.Therefore,Thebrittlefractureofweldingstructureisaproblemthatshouldbepaidmoreattentionto.8,plasmasprayingcharacteristicsandapplications?Answer:thecharacteristicoftheplasmasprayingisplasmaflametemperatureishigh,canmeltalmostallrefractorymaterial,sothattheobjectisveryextensive,sprayingtheplasmaflowvelocityishigh,theparticleaccelerationeffectisgood,sothecoatingwithhighbondingstrength.Ithasawiderangeofusesandisthebestwaytosprayallkindsofceramicmaterials.9,weldingprocesscardpreparationAnswer:theprocedureofweldingprocesscardshouldbebasedonproductassemblydrawingsandpartsprocessingdiagramanditstechnicalrequirements,findoutthecorrespondingweldingprocessevaluation,drawingsketchofjointweldingprocess;giveacardnumber,figurenumber,name,numberofjointjointweldingqualificationnumberandweldercertifiedproject;accordingtotheevaluationofweldingprocessandtheactualtheproductionconditionsandproductionexperienceandtechnologytoprepareweldingsequence;accordingtotheweldingprocedurequalificationspecificweldingparameters;determinetheproductinspectionagencies,accordingtoproductdesignrequirementsandproductstandardtestmethodsandinspectionproportion.