机械类英语论文翻译

铜陵学院期末论文1InfluenceofHotPressFormingTechniquesonPropertiesofVehicleHighStrengthSteels(SchoolofAutomotiveEngineering,StateKeyLaboratoryofStructuralAnalysisforIndustrialEquipment,DalianUniversityofTechnology,Dalian116024,Liaoning,China)Abstract:Basedonthecombinationofmaterialsscienceandmechanicalengineering,hotpressformingprocessofthevehiclehighstrengthsteelswasanalyzed.Thehotformingprocessinclud-ed:heatingalloysrapidlytoaustenitemicrostructures,stampingandcoolingtimely,maintainingpressureandquenching.Theresultsshowedthatmostofaustenitemicrostructurewaschangedintouniformmartensitebythehotpressformingwhilethesampleswereheatedat900。Candquenched.Theoptimaltensilestrengthandyieldstrengthwereupto1530MPaand1000MPa,respectively,andtheshapedeformationreachedabout23%.Andspringbackdefectdidnothapp-eninthesamples.Keywords:highstrengthsteel;lightweight;hotforming;martensiteAsaneffectiveeconomicalenergymeasure,thelightweightdevelopmentdirectionofautomo-bilehasbecomeoneofthemostimportantresearchsubjectsintheautomotiveindustry.Therearethreemajorwaystoachieveautomobilelightweight:optimizingvehicleframesandstruc-tures;makingvehiclebodyorframeofnewandalternativematerialstoreducethevehiclemass(Thehighandultrahighstrengthsteelcanbeusedasalternativematerialsbecauseofitsthinnerthickness);adoptingadvancedmanufacturingtechniquesforthesakeofautomobilelightwei-ght,suchasthickness-gradienthighstrengthsteel(HSS)ormetalbasedcompoundplatesbycon-tinuouspressingorhotpressforming[1].AlthoughHSShasbeenappliedinsomedomestictopgradevehicles,thekeyproducingtechnologieshavealwaysbeendominatedbyforeigncompan-ies,suchasAcelorCompany,soastoraisetheproductcostobviously.Bydomesticself-designedhotpressformingtechniquesandwater-coolingmould,theautomobileHSScanbeproducedtosubstituteforeignvehicleparts.Ingeneral,withtheenhancementofsteelblank，smechanicalstrength,itsformabilityisworseneddramatically.ItisdifficulttoapplythetraditionalcoldstampingtechnologyintothefieldofpressingHSS.Thus,thehotstampingtechnologyofmartensiticsteelblankisappliedasanewtechnology,whichcombinesmetalthermoplasticformingmethodandwater-coolingmouldquenchingprinciple.Inthispaper,boronsteelblankwasformedandwater-coolingmouldwasquenchedsimultaneouslyduringtheprocessofhotstamping.Comparedwithoriginalautomobilepearlitesteel[2],theautomobileHSSobtainedbyadvancedhotpressformingtechniquecanreduceabout30%ofthetotalvehiclemassandachievecomplexgeometries,highsecurityandmechanicalstrength.Thereasonisthataustenitemicrostructurewithoptimalplasticityandductilitycanbeobtainedbyhotpressformingathigh程艳.热压成形技术对汽车高强度钢性能影响（翻译）2temperature[3-5],andtheHSSwithbothexcellentmechanicalpropertiesandlightweightwillbeobtainedafterbeingformedandquenched[6-8].Theapplicationofhot-formedthinnerHSSplateswillbecomanimportantmeasuretorealizevehiclelightweight.1ExperimentalSetupInordertoformHSSathightemperature,andtoavoidcracksandspringback,thesam-plesneedrapidheatingandtransformcompletelyintostableaustenitemicrostructure.Andthen,samplesarepressedandcooledinself-madewater-coolingmould.FortheobtainedHS-Ssample,itsshape-freezingcharacterornospringbackdefectisanobviousadvantage,andmostofmicrostructureinthesampleismartensite.Thethicknessofsampleis1.6mm,andthemainelementsofHSSinthisexperimentareshowninTable1.Table1Mainelementsofmaterialintheexperimen22MnB5CMnCrSiBPSAlMinimum0.2201.2000.1100.0020.002--0.020Maximum0.2501.4000.2000.0050.0050.0200.0050.050Actualexperimentalprocedureincluded:1)setdifferentheattreatmenttemperaturesintherangeof750to1000℃;2)putthesampleintotheheattreatedfurnacetobeheatedfor4minatacertaintemperature;3)removeitbymechanicalhandandputitintothehotformingmouldstobepressedquickly;4)simultaneously,itwaswater-cooledatabout30℃/sinthemound.Themechanicalpropertiesofsamplewereanalyzedbytensiletestsystemandthemicrostructureappearancewasanalyzedbymetallographicanalysisdevice.TheshapeandsizeoftestsampleareshowninFig.1.Fig1Theshapeandsizeofspecimen2ResultsandDiscussionMechanicalpropertiesofHSS(boronsteels)withdifferentthicknesses(1.0mm,1.6mm,2.0mm,2.5mm,3.0mmand4.0mm,respectively)werechecked(GBT16865-1997wasconsulted,andsampleswereselectedalong0℃,45℃and90℃rollingdirectionrespec-tively).Theunidirectionaltensiletests(basedonthemetaltensiletestingstandardofGBT228-2002)werefinished.ComparedwithUSIBOR1500,thevaluesofbasicmechanicalpropertiesforHSSwithdifferentthicknessesintheexperimentareshowninFig2.Fig2showsthatafterwater-coolingquenching,thetensilestrengthandyieldstrengthofsamples(excepttheonewiththicknessof4.0mm)reached1500MPaand1000MPa,respectively.Thevaluesofthestrengthweretwicebetterthanthoseof铜陵学院期末论文3samplesbeforequenching,andnearlythesametothoseoftheplatesofthickness1.75mmfromAcelorCompany(USIBOR1500showninFig1).Fig2Tensileandyieldstrengthofhighstrengthsteelswithdifferentthicknessesbeforeandafterquench–ingGenerally,hotpressformingofsamplesisoperatedabovetransitiontemperatureofmartensitemicrostructure.Theheatingtemperatureinthisexperimentwasintherangeof750to1000℃becauseittook3sorsoforthesamplestobedeliveredintheair