资源描述：
《metalworking basics of metal casting外语英文电子书》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、1Lecture2.BasicsofMetal-Casting2.1.CastingmethodsMetalcastingprocessbeginsbycreatingamold,whichisthe‘reverse’shapeofthepartweneed.Themoldismadefromarefractorymaterial,forexample,sand.Themetalisheatedinanovenuntilitmelts,andthemoltenmetalispouredintothemouldcavity.Theliquidtakesthesha
2、peofcavity,whichistheshapeofthepart.Itiscooleduntilitsolidifies.Finally,thesolidifiedmetalpartisremovedfromthemould.Alargenumberofmetalcomponentsindesignsweuseeverydayaremadebycasting.Thereasonsforthisinclude:(a)Castingcanproduceverycomplexgeometrypartswithinternalcavitiesandhollowse
3、ctions.(b)Itcanbeusedtomakesmall(fewhundredgrams)toverylargesizeparts(thousandsofkilograms)(c)Itiseconomical,withverylittlewastage:theextrametalineachcastingisre-meltedandre-used(d)Castmetalisisotropic–ithasthesamephysical/mechanicalpropertiesalonganydirection.Commonexamples:doorhand
4、les,locks,theoutercasingorhousingformotors,pumps,etc.,wheelsofmanycars.Castingisalsoheavilyusedinthetoyindustrytomakeparts,e.g.toycars,planes,andsoon.Table1summarizesdifferenttypesofcastings,theiradvantages,disadvantagesandexamples.ProcessAdvantagesDisadvantagesExamplesSandWiderangeo
5、fmetals,sizes,shapes,lowpoorfinish,widetoleranceengineblocks,cylindercostheadsShellmoldbetteraccuracy,finish,higherproductionlimitedpartsizeconnectingrods,gearratehousingsExpendableWiderangeofmetals,sizes,shapespatternshavelowstrengthcylinderheads,brakepatterncomponentsPlastermoldcom
6、plexshapes,goodsurfacefinishnon-ferrousmetals,lowprototypesofmechanicalproductionratepartsCeramicmoldcomplexshapes,highaccuracy,goodsmallsizesimpellers,injectionmoldfinishtoolingInvestmentcomplexshapes,excellentfinishsmallparts,expensivejewelleryPermanentmoldgoodfinish,lowporosity,hi
7、ghCostlymold,simplergears,gearhousingsproductionrateshapesonlyDieExcellentdimensionalaccuracy,highcostlydies,smallparts,precisiongears,cameraproductionratenon-ferrousmetalsbodies,carwheelsCentrifugalLargecylindricalparts,goodqualityExpensive,limitedshapespipes,boilers,flywheels22.1.1
8、SandcastingF
