模具专业英语课件- unit one

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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