简介：TheunstabledimensionaldistortionofLF21aluminumalloyweldmentsatroomtemperatureandafterthermalcycleswasstudiedbyuseoflightinterferenceandCMM.Atthesametime,distortionmechanismwasanalyzedfromtheviewpointofmechanicsandmicrostructure.ExperimentalresultsshowthatthereexistsobviousdifferenceofunstabledimensionaldistortionbetweenLF21weldedspecimensundertwoconditionsmentionedabove.Underroomtemperature,dimensionalvariationofweldedspecimenswilldecreasegraduallyandfinallytendstobestableduring130hafterwelding.Therelativeelongationofweldedspecimenis4.2×10-5.Afterthermalcycles,distortionofweldedspecimenismuchlargerthanthatatroomtemperature.After11thermalcycles,thedimensionwilltendtobestable.Dimensionalunstabledistortionofweldmentsmainlyresultsfromtemperaturecondition,microstructurevariationandrelaxationofweldingresidualstress.

简介：Adigitalcontrolofpulsedgasmetalarcweldinginverterwasproposed.AcontrolsystemconsistingofanaloguepartswasreplacedwithanewdigitalcontrolimplementedinaTMS320LF2407ADSPchip.Thedesignandconstructionalfeaturesofthewholedigitalcontrolwerepresented.TheresourcesoftheDSPchipwereefficientlyutilizedandthecircuitsareveryconcise,whichcanenhancethestabilityandreliabilityofweldinginverter.Experimentalresultsdemonstratethatthedevelopeddigitalcontrolhastheabilitytoaccomplishtheexcellentpulsedgasmetalarcweldingprocessandthemeritsofthedevelopeddigitalcontrolarestableweldingprocess,littlespatterandperfectweldappearance.