钢材种类和变形的基础知识.ppt

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1、BasicKnowledgeofSteelandPlasticMechanics基础钢和塑性变形知识Contents1.SteelMechanicalpropertiesWorldwidesteelgradesAdvancedhighstrengthsteel(AHSS)2.PlasticmechanicsSheetdeformationmodesForminglimitsYieldcriteria2Introductiontoelasticityandplasticity固体材料受外力作用产生变形，从变形开始到破坏一般要经历两个阶段：弹性变形(elasticdeformatio

2、n)和塑性变形(plasticdeformation)。外力卸载后，弹性变形能够完全消失，而塑性变形不能消失。弹性变形和塑性变形的机理：材料原子之间的作用力平衡。位错(dislocation)理论。强化机制(workhardeningmechanism)。Dislocationmovement3UniaxialtensiletestGB/T228金属材料室温拉伸试验方法EN10002-1Metallicmaterials-Tensiletest-Part1:testmethod(inambienttemperature)Typicaltensiletestpiece4Engine

3、eringstress-straincurve5Engineeringstress-straincurve6StrengthandDuctilityStrengthparametersEngineeringstressEngineeringstrainElongationReductionofareaDuctility7Truestress-straincurveTruestressTruestrain8Workinghardening(strainhardening)Strainhardeningexponent(n-value)9Influenceofstrain-harde

4、ningexponentn3n2n110Anisotropy(R-value)Widthstrain:εw=ln(w/w0)Thicknessstrain:εt=ln(t/t0)R=εw/εtPlanaranisotropyratioNormalplasticanisotropyratio11StrainratesensitivityStrainrateStrainratesensitivityexponentStrainratesensitivityhasacrucialinfluenceontheresearchofcrashresistanceandhigh-speedst

5、ampingformability.12Worldwidesteelgrades13Worldwidesteelgrades14CommonsteeltypesandevolvingAHSStypesInterstitialfree(IF)steelsMildsteelsBakehardenable(BH)steelsIsotropic(IS)steelsCarbon-manganese(CM)steelsHigh-strengthlow-alloy(HSLA)steelsDualphase(DP)steelsTransformationinducedplasticity(TRI

6、P)steelsComplexphase(CP)steelsMartensitic(Mart)steels15Strengtheningmechanism16HSLAsteel17GradesofHSLAsteelinEU18ApplicationofHSLAsteel19Dualphase(DP)steel20EUsteelgradesComparisonEuropeansteelgrades(Mildsteel,HSLA,Dual-Phase)Legend:ColdRolledHotRolledDualPhasecoldrolled(valuesfromARCELOR)N

7、otfornewproducts!:AvailibilitytobeclarifiedFromClausUnruh21DimensionavailabilityAvailabilitycheckmaterialsEuropeversusUS–updateNov2006(onlyacc.myinformation;mustbecheckedandconfirmedbyPurchasingdepartment)Materialavailibilityofstandardmateria