外文翻译--船舶焊接.doc

Weldingistoensurethattheshipoftheshipandthestrengthofthekey.Thispaperdescribestheshipintheweldingofseveralcommonreasonsfortheshortcomingsandproposepreventivemeasures.Weldingistoensurethattheshipoftheshipandthestrengthofthekeyistoensurethatthekeytothequalityoftheship,istoensurethesafetyofshipsnavigatingandoperatinganimportantconditionfor.Ifthereisaweldingdefect,itmaycausestructuralfaults,leakage,orevencausetheshipsank.Accordingtotheshipbrittlefractureaccidentinvestigationshowedthat40percentofbrittlefracturefromtheaccidentwasthebeginningofthewelddefects.Shipsinthetownshipinshipbuilding,shiptheweldingqualityisparticularlyprominent.Intheinspectionofshipsintheprocessofweldingthetestisparticularlyimportant.Therefore,shouldtheearlydetectionofdefects,theweldingdefectsrestrictedtoacertainextent,toensurenavigationalsafety.Manytypesofshipweldingdefects,accordingtotheirdifferentpositions,thedefectscanbedividedintoexternalandinternaldefects.Defectshavepores,slag,weldingcracks,lackofpenetration,notfusion,weldandshapeofDimensionarenotmet,thebitingedge,ofwelding,suchasarcpit.firststomatalporestomatalporemeansthatthewelding,bubblebathinthesolidificationofthefailedescapetheholeformed.Themainreasontherehavestomata:grooveedgeofdirty,water,oilandXiuji；electrodeornotprovisionsofcuringflux,solderorrust-coreskindegeneration,suchasspalling.Inaddition,low-hydrogenweldingelectrode,thearcistoolong,weldingtoofast；submergedarcweldingvoltagetoohigh,areeasilygeneratedintheprocessofweldingstomata.Becausethepresenceofporositysothattheseamofeffectivecross-sectiondecreased,toolargeporeswillreducethestrengthofwelds,thedestructionoftheweldmetaldensity.Preventionistohaveastoma:choosetherightweldingcurrentAndweldingspeedandgrooveedgetocleanupwater,oilandXiuji.Strictlyinaccordancewiththeregulationscustody,clearingandcuringweldingmaterials.Nottousedegenerateelectrode,whentheskindegenerationdrugdiscoveryelectrode,spallingorweldingcorecorrosion,shouldstrictlycontroltheuseof.SAW,shouldusetheappropriateweldingprocessparameters,particularlytheplateautomaticwelding,weldingspeedshouldbeassmallaspossiblemore.Sendcent,slagSlagistheresidueoftheweldslag.Weldslagwillalsoreducetheintensityanddensity.AslagisthemainreasonforWeldaerobiccuttingedgeofgasorcarbonarcshaverresidualslag；grooveangleorweldingcurrentistoosmall,toofastorwelding.Acidintheuseofelectrode,thecurrentistoosmallorbecauseofimpropertransportofapasteresiduetousealkalineelectrode,thearcistoolongorbecauseofincorrectpolaritywillcausetheslag.ASAWbackcover,fromweldingwirecenter,butalsoeasytoslagformation.PreventionSlagproducedthemeasuresare:selecttherightgroovesize,tocleanupgrooveedge,choosetherightweldingcurrentandweldingspeed,andtransportoftheswingshouldbeappropriate.Multi-welding,shouldbecarefullyobservedgrooveonbothsidesofmelting,eachlayermustbeweldedtocleanupweldingslag.Backcoverweldingslagshouldbethoroughlyremoved,SAWattentionshouldbepaidtopreventthesolderside.Third,biteWeldleftedgeoftheDepression,knownasthebitingedge.Abitingedgebecausetheweldingcurrentistoolarge,Yunofthespeedandarcweldingrodstretchedtoolongorinappropriateangle.SAWweldingspeedtoofastorwelderorbitcausesofinequality,willcausethemeltingofweldingtoacertaindepth,andfilledwithmetalalsofailedtofilltheresultingbitingedge.Reducethebitingedgeofthebasemetaljointcross-sectionofwork,therebyresultinginthebitingedgeofstressconcentration,itwasimportanttothestructureorstructureofthedynamicload,isgenerallynotallowedtobiteWhilethere,ortobite-depthlimit.Bite-preventionapproachis:Choosetherightoftheweldingcurrentandtransportpractices,theattentionofcontrolatanytimearcweldingrodangleandlength；SAWprocessparameterstobeappropriate,withspecialattentiontoweldingspeedshouldnotbetoohigh,weldingmachinetotrackformation.Fourth,lackofpenetration,nofusionWelding,thejointswerenotfullyrootpenetrationofthephenomenon,knownasthelackofpenetrationintheweldingpiecesofmetalandweldseamorapartiallayerofpenetrationphenomenon,knownasFusiondidnot.Lackofpenetrationorfusionisamoreseriousflaw,sincelackofpenetrationorfusion,Weldwillappearintermittentormutation,weldstrengthgreatlyreduced,orevencausecracks.Therefore,inthehulloftheimportantpartsofthestructuredoesnotallowexistenceoflackofpenetration,thesituationisnotfusion.LackofpenetrationandfusionisnotthecauseoftheweldingassemblyspaceorslopeargumentOfsmall,blunt-thick,toomuchelectrodediameter,thecurrentistoosmall,toofastandtoolongarc,andsoon.Weldmentgroovesurfaceoxidefilm,oil,andsodidnotremoveclean,orwhenitflowsintheweldingofmetalslaghinderthetransportofthefusionorimproperpractices,thearcinthegroovewhilepartialandotherreasons,willnotcausetheedgefusion.Preventthelackofpenetrationorfusionapproachistherightsizeselectedgroove,areasonablechoiceofweldingcurrentandspeed,grooveandthesurfaceofskintoremoveoilpollutionclean；backcoverwelding-rootsthoroughly,andtransportoftheswingshouldbeappropriate,paycloseattentiontoslopeIfusiononbothsidesofthesituation.fifth,weldingcracksWeldingCrackisaveryseriousshortcomings.Morefromthedestructionofthecracks,intheprocessofweldingtotakeallnecessarymeasurestopreventtheemergenceofcrackintheweldingusedvariousmethodstocheckforcracks.Foundacrack,shouldberemoved,andthentorepair.Weldingcrackahotcrack,crackcold.Weldmetalfromliquidtosolidinthecrystallizationprocessknownasthecrackofcrack,itscharacteristicisthatimmediatelyafterthewelding,andmoreinthecenterseamalongtheseamlengthofthedistribution.Heatcracksthesurfacethroughoutmostofthegap,showingofcolor,slightlycracktheendofround.Ahotcrackintheweldpoolbecausetherearelowmeltingpointimpurities(suchasFeS,etc.).Asaresultoftheseimpuritieslowmeltingpoint,crystalsolidifiedthelatest,afterthesolidificationofplasticandintensityisverylow.BecauseThis,inthestructureofbindingstressenoughtheoutsideworldandthesolidificationoftheweldmetalcontraction,thepooloflowmeltingpointoftheseimpuritiesinthesolidificationprocesswasstarted,orshortlyafterbeingopenedcoagulation,resultingincracksbetweenthecrystal.Weldingelectrode,andpiecesofsulphur,copperandotherimpuritiesinalongtime,butalsoeasytoproducethermalcracks.Preventhotcrackthemeasuresareasfollows:1tostrictlycontroltheweldingprocessparameters,slowdownthecoolingrate,toincreaseweldshapefactor,asfaraspossible,usingsmallcurrentmulti-channelmulti-welding,inordertoavoidweldcracksCentreandtheotherisseriouslyTheimplementationofapointoforder,selectareasonableweldingprocess,weldingtoreducestress.Weldmetalinthecoolingprocessorcooling,thebasemetalorinthebasemetalandweldthejunctionofthefusionlineknownasthecoldcrackcrack.Suchcracksarelikelytoariseimmediatelyaftertheweldingisalsopossibleinafewhoursafterwelding,afewdaysorevenlongerbeforethere.Coldcrackthemainreasonfor:1)theroleofheatcycle,theheat-affectedzonegeneratedHardenedorganizations,2)aweldintheexcessiveproliferationofhydrogen,andhasaconcentrationoftheconditions3)jointbearBindingagreaterstress.PreventThecoldcrackmeasuresare:1)choiceoflow-hydrogenelectrode,intheweldtoreducethespreadofthecontentofhydrogen,2)strictlyabidebytheweldingmaterials(electrode,Flux)custody,baking,usethesystem,guardagainstexposedtomoisture,3)carefullycleaningupslopeIedgeoftheoilpollution,waterandXiuji,toreducethesourcesofhydrogen,4)Accordingtomaterialgradesofcarbonequivalent,componentthickness,theenvironment,suchaswelding,areasonablechoiceoftheweldingprocessparametersandenergylines,suchasweldingbeforepreheating,solderAfterthecoldease,takingmulti-channelmulti-welding,acertainlevelofcontroltemperature,5)aftertheheatemergencyTreatmenttodehydrogenase,toeliminatethestressandtemperhardenedorganizations,toimprovejointtoughness；6)thereasonableuseofweldingprocedures,theuseofsub-retreatlaw,suchaswelding,andweldingtoreducestress.sixth,otherflawsWeldingisalsocommontoanumberofwelding,arcweldingpitandontheexternaldimensionsandshapeofthedefect.Aweldingofthemainreasonsistheunevendistributionoftransport,resultingpooltemperatureistoohigh,theliquidmetalsolidifiedslowlyfalling,thusformedonthesurfaceoftheweldmetalaneurysm.Li,Yangwelding,theuseoftoomuchcurrentandarcwelding,butalsolikelytobeofwelding.Hanggeneratedarcisputoutthe