钛合金

2010,Vol.31,No.3　　　TRANSACTIONSOFTHECHINAWELDINGINSTITUTION

University,Xiπan710049,China).p37-40

Abstract:Anumericalcalculationmodelwithlocalrefinedmeshforlaserdeeppenetrationweldingoftitaniumalloyispres2ented.ARotatry2Gaussbodyheatsourcemodelwasestablishedtoaccuratelydescribetheshapeofkeyholeandmoltenpoolofthelaserweldedjoint.Theprofileofkeyholeandmoltenpoolaswellasthedistributionofhighgradientresidualstresseareobtained.Itisshowedthattheregionofhighstresslocatesinthekeyholeregion,andhighgradientresidualstressdistributesintheotherregionofweldedseam.Thestressegradientincreasesinthestateofexcessivelyhighandlowlevelofenergydensityaswellasthestateoflowerlinearenergy.Itissupposedthatkeepingthelaserenergydensityinstateoflowandmediumlevelorkeepingthelinearenergyinstateoflowlevelcouldavoidthehighgradientstresses.

Keywords:　highgradient;residualstresses;energyden2sity;linearenergy;keyhole

Researchonmeltingmetalbehaviorofultrasonic2tungsteninertgaswelding　　SUNQingjie,YANGChunli,LINSan2bao,FANYangyang(StateKeyLaboratoryofAdvancedWeldingProductionTechnology,HarbinInstituteofTechnology,Harbin150001,China).p41-44

Abstract:　Themechanismofmeltingbehaviorofmetalunderultrasonic2tungsteninertgas(U2TIG)weldingied.TheresultsindicatethatU2TIGen2hancethearcforceandelectrmetalflowbehavior,ratioofdepthtothelicationrangeandimprovesprordinaryTIGwelding.Besides,themechanismofforceenhancingandpenetrationincreasingwerealsopresentedincombinationwithexperimentandtheoreti2calanalysis.

Keywords:　ultrasonic2tungsteninertgaswelding;arcforce;arcshape;meltingbehavior

Effectofsprayparametersonmicrostructureofplasmasprayedwollastonitecoatings　　HUANGQing,WANGWeize,WANLei,XUANFuzhen(KeyLabofSafetyScienceofPressurizedSystem,MinistryofEducation,SchoolofMechanicalandPowerEngineering,EastChinaUniversityofScienceandTechnology,Shanghai200237,China).p45-48

Abstract:　Wollastonitecoatingwaspreparedbyplasmasprayingatdifferentsprayingdistances,primarygasflowratesandplasmapower.Themicrostructureofthecoatinglagerwasexaminedbyscanningelectronmicroscope(SEM).Theresultsshowthatthethreesprayingparametersaffectthemicrostructureofwollastonitecoatingsgreatly.Flattendegreeofmoltenpowderdecreasedandthenumberofporesincreasedwiththeincrementofsprayingdistanceatlargerflowrateofprimarygas.However,flattendegreeofmoltenpowderfirstlyincreasedandthende2creasedwiththesprayingdistanceatthelowerflowrateofprima2rygas.Themicrostructureofcoatingsisdenserwithlargergasflowrate.Flattendegreeincreasedwithplasmapowerupto36kW.Furtherincreaseofplasmapowerresultsinmoreroundporesappearingincoatings.Effectofsprayparametersonthemicrostructureofwollastonitecoatingsmainlyresultedfromthe

Ⅲ

influenceonvelocityandtemperatureofthemoltendroplets.

Keywords:　plasmaspraying;wollastonitecoating;spra2yingdistance;plasmapower;gasflowrateInfluenceoftransversealternativemagneticfieldonmicro2structureandpropertiesofplasmaarcsurfacinglayer　　LIUZhengjun,ZHAOQian,SONGXingkui,YANGYang(SchoolofMaterialScienceandEngineering,ShenyangUniver2sityofTechnology,Shenyang110870,China).p49-52Abstract:　Intheresearchoftheinfluenceofalternativepulsedmagneticfieldonmicrostructureandpropertiesofnickel2basealloy,atransversealternativepulsedmagneticfieldhadbeenappliedtotheplasmaarcsurfacingweldingonlowcarbonsteel.Thehardness,wearresistanceandmicrostructureofsurfa2cinglayerwithdifferentpulsedmagneticfieldcurrents,dutycy2cleshavebeensystematicallyanalyzed.Theresultsindicatedthattransversealternativepulsedmagneticfieldcaneffectivelyim2provethecrystalshapeofplasmaarcsurfacinglayer,refinecrys2talgrain.Properpulsedmagneticfieldcurrent,dutycyclecanobtaintheoptimumeffectonelectrostirring,whichcanincreasetheamountofhardeningoverlaydeposit,con2trolthegrandimprovetheoverlay.

　transversemagneticfield;mi2Investigationonweldingstressandstrainoftitaniumalloy　　LIJu1,GUANQiao1,SHIYaowu2(1.BeijingAeronauticalManufacturingTechnologyResearchInstitute,P.O.Box863,Beijing100024,China;2.SchoolofMaterialScienceandTech2nology,BeijingUniversityofTechnology,Beijing100022,Chi2na).p53-56,60

Abstract:　Theweldingstressandstrainwereinvestigatedusingthefiniteelementmethodcombinedwiththeexperiments.Theresearchresultsshowedthatthemetalinthemeltingpoolismeltedintheframeofareawithcompressiveplasticstrain,andcooleddownalsointheframeoftheareawithcompressiveplasticstrain.Thetensileplasticstrainisproducedintheweldwhenitisinthestateof‘mechanicalmelting’duringthecoolingprocess.Butintheresidualstate,thecompressiveplasticstrainstillremainsintheweld.Thepeakvalueoflongitudinaltensilestressintheweldoftitaniumalloyisalwayslowerthanitsyieldstrengthattheappropriatetemperatureduringthecoolingprocess,thissituationiskeptuntiltheresidualstate.

Keywords:　titaniumalloy;welding;stress;strainFiniteelementanlysisofweldingsequenceimpactonblisk

1,31,2

roundness　　ZHANGXueqiu,YANGJianguo,LIUXue2

112

song,CHENXuhui,FANGHongyuan,QUShen(1.StateKeyLaboratoryofAdvancedWeldingProductionTechnology,HarbinInstituteofTechnology,Harbin150001,China;2.She2nyangLimingAero2EngineGroupCorporation,Shenyang110043,China;3.BaosteelGroupCorporation,Shanghai201900,China).p57-60

Abstract:　Thefiniteelementmodelofbliskismadebytheseveralsoftwaresandbasedonthedifferenttemperatureeffectsduringtheweldingprocess,threekindsoftypicalwelding