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1、Lesson1Positionofmetalforminginmodernindustry金属成形在现代工业中的地位Metalformingisoneofthefundamentalmanufacturingprocess.Itplaysanimportantpartinmetallurgy冶金,machinebuilding机械制造,power电力,autobile汽车,railroad,aerospace航空,ship-building,weapon,chemical化工,electronics电子,i
2、nstrumentandmetermaking仪器和仪表制造andlightindustries轻工业.金属成形是材料的塑性加工过程。在金属成形工艺中，最初的简单零件,坯料或板料通过在模具之间变形而获得所需零件的最终形状。由于模具具有所需零件的几何形状，通过模具内表面对变形材料施压，简单形状的零件就会变成复杂形状的零件。金属成形很少产生废料甚至不产生废料，并且往往在很短时间内（即压力机或锻锤的一次或几次行程中）形成产品形状。因此，金属成形可节能省材。特别是在大中批量生产时，模具成本容易收回。另外，对于给定重
3、量的零件，用金属成形加工比用铸造和切削加工生产具有更好的力学性能、冶金性能和可靠性。Atpresent,netshapemanufacturing净形制造andnearnetshapemanufacturing近净形制造havebecomethefocusofstudies研究的焦点pursed追逐bythemetalformingcircle领域.Researchinstitutions研究学会，研究机构concentratingonthestudyofnetshapemanufacturing净形制造h
4、avebeenestablished建立andenormous巨大fundsandminds财力与智力invested.Netshapemanufacturingisvigorouslydevelopingthroughouttheworld.Bytheapplicationofcoldextrusion冷挤压,coldheading冷镦,precisiondieforging精密模锻,specialrolling特殊滚压,fineblanking精冲,spinning旋压,multi-ramforging
5、多向模锻,multi-positionpressing多工位压制,high-speedpressingwithprogressivedies级进模高速冲压,powderforging粉末锻压,superplasticforming超塑性成形andlaserprocessing激光加工,finishedpartscanbeproducedwithhighaccuracy高精确度,lowsurfacecrudeness粗糙度.Thedayshavealreadygonewhen（定语从句）metalformin
6、gwasconsidered认为asaprocessbywhichonly认为asaprocessbywhichonlysemifinishedproductscouldbemade（从句）.Itispredicted预测by…that（从句）bytheyear2000metalformingcombinedwiththeyear2000metalformingcombinedwithgrindingtechnology（定语）磨削工艺willreplacemostofmetalcutting.Lesson
7、2ClassificationofMetalFormingProcessesNearlyallmentalformingprocessesinvolvetheworkpiecebeingsubjectedtocomplexstressstates(处于复杂应力状态下)whichcanvaryfrom,saytriaxialcompression(三向压应力)tobiaxialtension(两向拉应力).However,shearstresses(剪切应力)neednotbeconsideredunless
8、theyconstitute(构成)majorstressestowhichtheworkpieceissubjectedandarethusinfluentialincontributingtoplasticdeformation.Mostofthecomplexstressstatescanbeapproximated(近似)bytheirprincipalstresscomponents(主应力),that
