简介：ThesusceptibilityofweldedjointfortheX65pipelinesteeltoH2Sstresscorrosioncracking(SCC)isinvestigated.SCCtestsonthesteelarecarriedoutintheenvironmentbasedonNACETM-01-77solutionwithsaturatedgaseousH2S.Thethresholdstressintensityfactorandcrackpropagationvelocityarecalculatedaccordingtowedge-openingloading(WOL)specimens.Thethree-dimensionalelastic-plasticfiniteelementanalysisofWOLspecimensisperformedbyusingtheFEMprogrammingpackageANSYS.Stressfieldandconcentrationofhydrogendistributionpropertyaheadofthecracktipareobtained.ThispapersurveyedthemicrostructureofweldedjointandstudiedonthemechanicalpropertiesofX65pipelinesteel.Itprovidesexperimentalbasisforstudyingstresscorrosion.Theresultsofnumericalanalysisareconsistentwithconclusionsofstresscorrosiontest.

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简介：Inthisinvestigation,themechanicalpropertiesandlow-temperaturefracturetoughnessofAPI5LX65offshorepipelineweldedjointswerestudied.StructureIntegrityAssessmentProcedure(SINTAP)-FailureAssessmentDiagram(FAD)methodwasappliedtothepipestructurewithsurfaceflawattheweldtoe.AccordingtotheISOstandardBS7448,theCTODfracturetoughnessoftheweldedjointswasdeterminedatthetemperatureof0℃.Fortheheat-affectedzone(HAZ)specimens,post-testmetallographicanalysiswasperformedtoverifythatthetipofthecrackwaslocatedinthecoarsecrystalzoneinordertoconfirmthevalidityoftheaboveresults.Thefailurelinesofanalysislevel1and3ofweldmetalwerederivedfromtheresultsofthemechanicalpropertytest.Theassessmentwasperformed,consideringthemaximumlaystress,residualstressconservativelyassumedtobeuniformtensilestress,andminimumCTODvalue.Theresultsoftheassessmentshowedthatpipelinestructurewithasurfaceflaw(theheightandlengtharerespectively2.2mmand5mm)attheweldtoeissafe.ThisstudylaysthefoundationofapplicationofSINTAPtopipelinestructureassessment.

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简介：Whenmeasuringresidualstressofcoarse-grainaluminumalloyusingX-raydiffractionmethod,thediffractionprofileshowstwopeaksandpositionofmeasured2dwillbechanged,whichleadtoaninaccuratemeasurementresult.Hence,inthispaper,somemethodswereemployedtoimprovethemeasurementaccuracy.Duringthemeasuringprocess,differentparameters(diameterofirradiatedarea,Ψ-oscillationrangeandexposuretime)wereselectedandprofilepeakshiftmethodwasutilized.Moreover,whenthe20ofprofileswasdetermined,differentcalculationmethodswereusedtocalculatetheresidualstress.TheresultsshowthatdiameterofirradiatedareaandΨ-oscillationrangehavesignificantinfluenceonthemeasuringresult.Forstressvaluecalculateddirectlyfromthetestequipment,crosscorrelationmethodismoreaccuratethantheabsolutepeak.Furthermore,anothertwocalculationmethodsofslopewith2θ-sin~2Ψande-sin~2Ψwereusedtocalculatethestressbasedonparameters(2θ,ε)obtainedfromcrosscorrelationmethod.Itisconcludedthat20-sin~2Ψmethodcanfurtherimprovethemeasurementaccuracy.

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简介："GasTransmittingFromWesttoEastProject"issignificant.Itshouldensuretheweldingqualityandsafetyofpipeline.Thetaskisveryarduoustoguaranteethequalityoftheprojectintheconditionoflongline,complexweatherandgeologyfeatures.Inthispaper,theweldingcoldcrackingsusceptibilityofdomesticX-70pipelinesteeladoptedbytheproject,whichisoneofthemostinterestingquestionsofweldingqualityaboutpetrolpipeline,wasstudiedbymeansofobliqueY-groovecrackingtest.Thecrackratioofsurfaceandsectionwastestedundertheconditionsofdifferentweldingmaterialsandpreheattemperature.TheX-70pipelinesteelhasgoodcrackresistance.Theresearchhasimportantvaluefortheconstructionoflarge-scalepipelineengineeringandtheapplicationofdomesticX-70pipelinesteel.

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简介：BondingofAl2O3tocuisperformeddirectlyusingTifoilattemperatureof1273K.Themicrostructureofthejointinterfaceisinuestigatedthroughscanningelectronmicroscope（SEM）,electron.probemicroanalysis（EPMA）andX-raydiffraction（XRD）.theeffectoftheinitialtifoilthicknessonthereactionlayerthicknessandthejointStrengthareinvestigated.

简介：本文结合生产实践,简要分析提出了CO2气体保护焊目前所存在的缺陷与问题,并提出了相应的解决方法与CO2气体保护焊的发展趋势。

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简介：ＡｖｉｓｉｏｎｔｒａｃｋｉｎｇｓｙｓｔｅｍｏｆｒｏｂｏｔＣＯ２ｓｈｏｒｔｔｒａｎｓｆｅｒｗｅｌｄｉｎｇＷｕＲｅｎｙｕ；ＷａｎｇＧｕｏｄｏｎｇａｎｄＬｉＸｉａｏｑｉ（ＴｉａｎｊｉｎＵｎｉｖｅｒｓｉｔｙ）ＺｈａｎｇＬｉａｎｃｈａｎｇ(ＭｏｔｏｒｏｌａＣ?..

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简介：本文介绍了CO2气体保护电弧焊的冶金特点，CO2气体保护电弧焊焊接过程中的熔滴过渡形式；从焊丝的冶金过程，焊接时的工艺参数的选择及调整等方面探讨了汽车白车身CO2焊接质量的控制。

简介：IntheautomaticCO2arcwelding,thealterationoftheverticaldistancebetweentheweldingtorchandtheworkpiecehasastrongeffectontheweldingparameterssuchasweldingcurrentandvoltage,withtheresultthattheappearanceandqualityofweldarenotsteady.Toweakentheinfluenceofthedistancealteration,amethodisputforwardinthepaper.Themethodisthatthealternatewire-feedcontrolisusedforcompensatingtheweldingcurrent.Onthebasisoftheoreticalanalysis,astaticnumericalmodelforalternatewire-feedcontrolisestablished.Theexperimentsshowthatthemodel-basedregulationofthewirefeedratecancompensatetheweldingcurrentandensuretheappearanceofweld.Whenthealterationofverticaldistancebetweenthetorchandtheworkpieceisgreater,notonlyisthewirefeedrateregulated,buttheoutputvoltageofthepowersourceisadjustedtoensuretheappearanceandqualityofweld.

简介：本文介绍了CO2焊工艺方法及其高效、优质、低成本的综合优越性以及在石油、化工、天然气工程建设中的应用与发展,不同种类的气体与焊丝相组合的工艺特点及控制焊缝成形的操作技术。