工程材料及其成型技术基础.pdf

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1、工程材料及其成型技术基础EngineeringMaterialsandHeattreatmentEngineeringMaterialsandHeattreatment,likeitsname,therearemainlytwoparts,engineeringmaterialsandheattreatment.Forengineeringmaterials,Ilearnedsteel,castiron,andiron‐carbonphasediagram.Forheattreatment,Ilearnednormalizing,quenching,temperi

2、ngandannealing.1.Iron‐CarbonPhaseDiagramAHBJDNCFEGPSQABCD‐liquidline(upward)AHJECF‐solidline(downward)HJB‐peritecticlineL0.53%+δ0.09%‐>A0.17%ECF‐eutecticlineL4.3%‐>γ2.11%+Fe3CPSK‐entectoidlineγ0.77%‐>α0.0218%+Fe3CES‐liquidoidofCinaustentitePQ‐liquidoidofCinferriteGS‐whereγ‐>α+γorwhere

3、α+γ‐>γ ℃%ofCinformationA15380MeltingpointofpureironB14950.53CompositionofLwhileperitectictransformationC11484.3EutecticpointD12276.69MeltingpointofcementiteE11482.11ThelargestsolubilityofCtoγ‐FeF11486.69CompositionofcementiteG9120Temperaturewhereα‐Fe& γ‐FetransfertoeachotherH14950.09T

4、helargestsolubilityofCtoδ‐FeJ14950.17PeritecticpointK7276.69CompositionofcementiteN13940Temperaturewhereδ‐Fe& γ‐FetransfertoeachotherP7270.0218ThelargestsolubilityofCtoα‐FeS7270.77EutectoidpointQ6000.0057ThesolubilityofCtoα‐Fewhen600℃2.DiagramofstressandstrainofPlasticMaterial塑性材料的应力应

5、变图σ[N/mm2]FmaxRmUniformstrainConstrictionstrainReHReLε[%]AgAgtAAtAg=uniformstrainAgt=totalstrainatmaximumloadA=elongationatruptureAt=totalstrainafterbreakRm=tensilestrengthFmax=maximumloadReH=upperelasticlimitReL=lowerelasticlimit3.ThethreeunitcellstructuresCubicCubicHexagonalclose-pa

6、ckedBCC体心立方晶格FCC面心立方晶格HCP密排六方晶格Eg.FerriteEg.Austenite4.Heattreatment热处理(1).ObjectivesChangethefollowingpropertiesorconditionsofthesteel:a.improvethetoughnessb.increasethehardnessc.increasetheductilityd.improvethemachinabilitye.refinethegrainstructuref.removetheresidualstressg.improvet

7、hewearresistance(2).TypesNormalizing正火:Heatittoacertaintemperature,keepitforaperiodoftime,putitintheair,slowlycooltotheroomtemperature.Resultsinamoreuniformstructure;higherstrengththanannealedsteel;relativelyhighstrengthandductility.Quenching淬火:Heatittoacertaintemperature,putitintowat

8、eroro