钢材种类和变形的基础知识复习过程.ppt

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1、钢材种类和变形的基础知识Introductiontoelasticityandplasticity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(elasticdeformation)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)。Dislocationmovement2UniaxialtensiletestGB/T228金属材料室温

2、拉伸试验方法EN10002-1Metallicmaterials-Tensiletest-Part1:testmethod(inambienttemperature)Typicaltensiletestpiece3Engineeringstress-straincurve4Engineeringstress-straincurve5StrengthandDuctilityStrengthparametersEngineeringstressEngineeringstrainElongationReductionofareaDuctility6Truestres

3、s-straincurveTruestressTruestrain7Workinghardening(strainhardening)Strainhardeningexponent(n-value)8Influenceofstrain-hardeningexponentn3n2n19Anisotropy(R-value)Widthstrain:εw=ln(w/w0)Thicknessstrain:εt=ln(t/t0)R=εw/εtPlanaranisotropyratioNormalplasticanisotropyratio10Strainratesens

4、itivityStrainrateStrainratesensitivityexponentStrainratesensitivityhasacrucialinfluenceontheresearchofcrashresistanceandhigh-speedstampingformability.11Worldwidesteelgrades12Worldwidesteelgrades13CommonsteeltypesandevolvingAHSStypesInterstitialfree(IF)steelsMildsteelsBakehardenable(

5、BH)steelsIsotropic(IS)steelsCarbon-manganese(CM)steelsHigh-strengthlow-alloy(HSLA)steelsDualphase(DP)steelsTransformationinducedplasticity(TRIP)steelsComplexphase(CP)steelsMartensitic(Mart)steels14Strengtheningmechanism15HSLAsteel16GradesofHSLAsteelinEU17ApplicationofHSLAsteel18Dual

6、phase(DP)steel19EUsteelgradesComparisonEuropeansteelgrades(Mildsteel,HSLA,Dual-Phase)Legend:ColdRolledHotRolledDualPhasecoldrolled(valuesfromARCELOR)Notfornewproducts!:AvailibilitytobeclarifiedFromClausUnruh20DimensionavailabilityAvailabilitycheckmaterialsEuropeversusUS–updateNov2

7、006(onlyacc.myinformation;mustbecheckedandconfirmedbyPurchasingdepartment)Materialavailibilityofstandardmaterialsisgiven.MaterialavailibilityofS460MCisdecreasingeveninEurope.MaterialavailibilityofDualPhaseandotherspecialgradesmustcheckedforeachdimensionsFromClausUnruh21Dimensionav

8、ailabilityAvailabil