简介:ESD(electrosparkdeposition)isapromisingprocesstoproducehardandwear-resistingcoatingsonmetallicsubstrates.InthispapermicrostructureandinterfacialcharacteristicsoftheWC92-Co8coatedontitaniumandcarbonsteelarepresented.Ametallurgicalbondingbetweenthecoatingandsubstrateisobtained.TheTielementwasfoundtodistributeinWC92-Co8atthemetalpool,aswellastheinterfacebydiffusion.SomenewphaseswereproducedinthecoatinglayerduetothechemicalreactionduringtheESDprocess.ExperimentalobservationandthermodynamicanalysiswereutilizedtostudythemechanismofESD.
简介:Themechanicalproperties,creepdamage,creeprupturestrengthandfeaturesofinterfacialfailuresofweldedjointsbetweenmartensite(SA213T91)andpearlitesteel(12Cr1MoV)havebeeninvestigatedbymeansofargontungstenpulsedarcwelding,hightemperatureacceleratedsimulation,creeprupture,mechanicalpropertytestsandscanningelectronicmicroscope(SEM).Theresearchresultsindicatethatthemechanicalpropertiesofovermatchedandmediummatchedjointdeteriorateobviously,andtheyaresusceptibletocreepdamageandfailureafteracceleratedsimulationoperation500h,intheconditionofpreheat250℃,andpostweldingheattreatment750℃×1h.However,themechanicalpropertiesofundermatchedjointarethebest,theinterfacialfailuretendencyofundermatchedweldedjointislessthanthoseofmediumandovermatchedweldedjoint.Therefore,itisreasonablethatlowalloymaterialTR31isusedasthefillermetalofweldbetweenSA213T91and12Cr1MoVsteel.
简介:<正>据国家经贸委预测,2002年国际有色金属市场有以下特点:首先,联合重组加快,产业集中度提高。为了适应市场竞争,国外大企业近年来普遍加快了收购、兼并、联合步伐、组建更大规模的跨国公司(多数为采选冶加工联合企业),实现规模化运营,扩大市场份额。例如,美国铝业公司(Alcoa)是一家集铝土矿开采、氧化铝、电解铝生产和铝材加工为一体的综合性铝业集团,1998年兼并了美国阿鲁玛克斯(ALUMAX)公司,收购了世界第三大制铝公司美国雷诺兹金属公司(Reynolds),当年销售额达210亿美元,年生产铝352万吨,占世界铝产量的15%。
简介:ButtjointsofQCrO.8/1Cr2lNiSTiequal-thicknessdissimilarmaterialswereobtainedbyelectronbeamweldingwithfixedacceleratingvoltage60kVandfocuscurrent1.99A,changedelectronbeamcurrentandweldingvelocity.MicrostructureandcompositionoftheEBWjointwereinvestigatedbymeansofopticalmicrographyandEDXanalysis,mechanicalpropertiesofthejointwerealsotested.Theresultsshowthatjoint'smacrostructurewasdividedintothreezones:topweldzonenearQCrO.8andbottomweldzoneconsistingofCu(ss.Fe)withacertainamountofdispersedlydistributed(α+ε)mixedmicrostructure,middleweldzoneconsistingof(α+ε)microstracturewithasmallamountofCu(ss.Fe)particles.MorphologicalinhomogeneousmacrostructureandunevenchemicalcompostionofQCrO.8/1Cr21NiSTijointbyEBWarethemostimportantfactortoresultindecreasingjoiningstrength.
简介:GB/T15579.5-2005《弧焊设备安全要求第五部分:送丝装置》和GB/T15579.7-2005《弧焊设备安全要求第七部分:焊炬(枪)》(以下简称新标准)已于2005年12月1日正式实施。自新标准实施之日起.JB/T9533-1999《焊机送丝装置:技术条件》、JB/T9526-1999《TIG焊焊炬技术条件》和JB/T9532-1999《MIG/MAG焊焊枪技术条件》(以下简称旧标准)废止。