资源描述：
《刘瑶中期论文 修改》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、临沂师范学院本科专业职业生涯设计外文文献翻译模板1：2010届 本科专业外文文献翻译Heattreatmentofmetal金属热处理 姓名 刘滕宝 学号 200615840114 年级 2006 专业 机械设计制造及其自动化 系 （院） 工学院 指导教师 王宁宁 2010年01月15临沂师范学院本科专业职业生涯设计外文文献翻译HeattreatmentofmetalInindustrytodaytherearemorethanathousan
2、ddifferentmetalsbeingusedtomanufactureproducts.Themodernautomobilehasmorethanonehundreddifferentmetalsusedinitsconstruction.Anattemptwillbemadeinthispassagetogiveanunderstandingofthebasicclassificationofmetals.Metalswereformerlythoughttobethoseelementsthathadametalliclusterandweregoodconduct
3、orofheatandelectricity.Actually,metalsaregenerallydefinedasthoseelementswhosehydroxidesfrombases(suchassodiumorpotassium).thenonmetals’hydroxidesfromacids(suchassulphur).Metalsmayexistaspureelements.Whentwoormoremetallicelementsarecombined,theyformamixturecalledanalloyThetermalloyisusedtoide
4、ntifyanymetallicsystem.Inmetallurgyitisasubstance,withmetallicproperties,thatiscomposedoftwoormoreelements,intimatelymixed.Oftheseelementsonemustbeametal.Plaincarbonsteel,inthesense,isbasicallyanalloyofironandcarbon.Otherelementsarepresentintheformofimpurities.However,forcommercialpurposes,p
5、laincarbonsteelisnotclassifiedasanalloysteel.Alloymaybefurtherclassifiedasferrousandnonferrous.Ferrousalloyscontainiron.Nonferrousalloysdonotcontainiron.Allcommercialvarietiesofironandsteelarealloys.Theordinarysteelsarethoughtofasiron-carbonalloys.However,practicallyallcontainsiliconandmanga
6、neseaswell.Inaddition,therearethousandsofrecognizedalloysteels.Examplesarespecialtoolsteels,steelsforcastings,forgings,androlledshapes.Thebasemetalforalltheseisiron.Steelsareoftencalledbytheprincipalalloyingelementpresent.Examplesaresiliconsteel,manganesesteel,nickelsteel,andtungstensteel.Ev
7、ennonferrousalloysmaycontainironinasmallamount,asimpurities.Someofthenonferrousalloysarebronze,brass,andmonel.Althoughpuremetalssolidifyataconstanttemperature,alloysdonot.Thefirstnucleihaveatendencytoformatahighertemperaturethanthatatwhichcompletes
