简介:Adigitalcontrolofpulsedgasmetalarcweldinginverterwasproposed.AcontrolsystemconsistingofanaloguepartswasreplacedwithanewdigitalcontrolimplementedinaTMS320LF2407ADSPchip.Thedesignandconstructionalfeaturesofthewholedigitalcontrolwerepresented.TheresourcesoftheDSPchipwereefficientlyutilizedandthecircuitsareveryconcise,whichcanenhancethestabilityandreliabilityofweldinginverter.Experimentalresultsdemonstratethatthedevelopeddigitalcontrolhastheabilitytoaccomplishtheexcellentpulsedgasmetalarcweldingprocessandthemeritsofthedevelopeddigitalcontrolarestableweldingprocess,littlespatterandperfectweldappearance.
简介:ThesusceptibilityofweldedjointfortheX65pipelinesteeltoH2Sstresscorrosioncracking(SCC)isinvestigated.SCCtestsonthesteelarecarriedoutintheenvironmentbasedonNACETM-01-77solutionwithsaturatedgaseousH2S.Thethresholdstressintensityfactorandcrackpropagationvelocityarecalculatedaccordingtowedge-openingloading(WOL)specimens.Thethree-dimensionalelastic-plasticfiniteelementanalysisofWOLspecimensisperformedbyusingtheFEMprogrammingpackageANSYS.Stressfieldandconcentrationofhydrogendistributionpropertyaheadofthecracktipareobtained.ThispapersurveyedthemicrostructureofweldedjointandstudiedonthemechanicalpropertiesofX65pipelinesteel.Itprovidesexperimentalbasisforstudyingstresscorrosion.Theresultsofnumericalanalysisareconsistentwithconclusionsofstresscorrosiontest.