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ID:17833676
大小:1.55 MB
页数:97页
时间:2018-09-07
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1、模具专业英语UnitOneUnitOneMoldMaterialsandHeatTreatment1EngineeringMaterials2KindsofSteel3Polymers4MoldMaterials5HeatTreatmentofMetalsPassageOneEngineeringMaterialsUnitOneMoldMaterialsandHeatTreatmentMaterialsmaybegroupedinseveralways.Scientistsoftenclassifymaterialsbytheirstate:Solid,l
2、iquid,orgas.Theyalsoseparatethemintoorganic(onceliving)andinorganic(neverliving)materials.Forindustrialpurposes,materialsaredividedintoengineeringmaterialsornonengineeringmaterials.Engineeringmaterialsarethoseusedinmanufactureandbecomepartsofproducts.Nonengineeringmaterialsarethec
3、hemicals,fuels,lubricants,andothermaterialsusedinthemanufacturingprocesswhichdonotbecomepartoftheproduct.Engineeringmaterialsmaybeclassifiedintofourgroups:Metals,ceramics,polymers,andcompositematerials.11.MetalsUnitOneMoldMaterialsandHeatTreatmentMetalsandalloys,whichincludesteel,
4、aluminum,mag-nesium,zinc,castiron,titanium,copper,nickel,andmanyothers,havethegeneralcharacteristicsofgoodelectricalandthermalconductivity,relativelyhighstrength,highstiffness,ductilityorformability,andshockresistance.Theyareparticularlyusefulforstructuralorload-bearingapplication
5、s.Althoughpuremetalsareoccasionallyused,combinationsofmetalscalledalloysarenormallydesignedtoprovideimprovementinaparticulardesirablepropertyorpermitbettercombinationsofproperties.2.CeramicsUnitOneMoldMaterialsandHeatTreatmentCeramics,suchasbrick,glass,tableware,insulators,andabra
6、sives,havepoorelectricalandthermalconductivity.Althoughceramicsmayhavegoodstrengthandhardness,theirductility,formability,andshockresistancearepoor.Consequently,ceramicsarelessoftenusedforstructuralorload-bearingapplicationsthanmetals①.However,manyceramicshaveexcellentresistancetoh
7、ightemperaturesandcertaincorrosivemediaandhaveanumberofunusualanddesirableoptical,electrical,andthermalproperties.3.PolymersUnitOneMoldMaterialsandHeatTreatmentPolymersincluderubber,plastics,andmanytypesofadhesives.Theyareproducedbycreatinglargemolecularstructuresfromorganicmolecu
8、les,obtainedfrompetroleumoragricu
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