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1、Mainarticle:Casting(metalworking)[edit]MeltingMeltingisperformedinafurnace.Virginmaterial,externalscrap,internalscrap,andalloyingelementsareusedtochargethefurnace.Virginmaterialreferstocommerciallypureformsoftheprimarymetalusedtoformaparticularalloy.Alloyingelementsareeitherpureforms
2、ofanalloyingelement,likeelectrolyticnickel,oralloysoflimitedcomposition,suchasferroalloysormasteralloys.Externalscrapismaterialfromotherformingprocessessuchaspunching,forging,ormachining.Internalscrapconsistsofthegates,risers,ordefectivecastings.Theprocessincludesmeltingthecharge,ref
3、iningthemelt,adjustingthemeltchemistryandtappingintoatransportvessel.Refiningisdonetoremovedeleteriousgasesandelementsfromthemoltenmetaltoavoidecastingdefects.Materialisaddedduringthemeltingprocesstobringthefinalchemistrywithinaspecificrangespecifiedbyindustryand/orinternalstandards.
4、Duringthetap,finalchemistryadjustmentsaremade.[edit]FurnaceSeveralspecialisedfurnacesareusedtomeltthemetal.Furnacesarerefractorylinedvesselsthatcontainthematerialtobemeltedandprovidetheenergytomeltit.Modernfurnacetypesincludeelectricarcfurnaces(EAF),inductionfurnaces,cupolas,reverber
5、atory,andcruciblefurnaces.Furnacechoiceisdependentonthealloysystemandquantitiesproduced.Forferrousmaterials,EAFs,cupolas,andinductionfurnacesarecommonlyused.Reverberatoryandcruciblefurnacesarecommonforproducingaluminumcastings.Furnacedesignisacomplexprocess,andthedesigncanbeoptimized
6、basedonmultiplefactors.Furnacesinfoundriescanbeanysize,rangingfrommereouncestohundredsoftons,andtheyaredesignedaccordingtothetypeofmetalsthataretobemelted.Also,furnacesmustbedesignedaroundthefuelbeingusedtoproducethedesiredtemperature.Forlowtemperaturemeltingpointalloys,suchaszincort
7、in,meltingfurnacesmayreacharound327Celsius.Electricity,propane,ornaturalgasareusuallyusedforthesetemperatures.Forhighmeltingpointalloyssuchassteelornickelbasedalloys,thefurnacemustbedesignedfortemperaturesover3600Celsius.Thefuelusedtoreachthesehightemperaturescanbeelectricityorcoke.T
8、hemajorityof