金属热处理外文文献及翻译.docx

金属热处理外文文献及翻译.docx

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金属热处理外文文献及翻译

原文

Ｈｅat　trｅａtmeｎtｏf　ｍetal

Tｈegｅｎerallyａcｃeｐteｄ　dｅfｉniｔionforｈeａttreatinｇmｅtalsanｄmetaｌ　alloｙｓｉｓ　“hｅatｉng　andｃooｌｉnｇasolｉｄｍetalorａlloyｉｎａ　wayｓoasｔoobtaｉnsｐecifｉc　ｃondｉtionsorprｏｐertｉes."Hｅaｔinｇforthｅsoｌepurpose　of　hｏｔworkinｇ（as　iｎ　fｏrｇiｎgoperatｉons）iｓ　excluded　fｒomthiｓｄｅfiniｔｉon。

Ｌiｋewise,tｈetypｅｓof　ｈｅat　treatmeｎt　thataｒesometｉmｅsuｓedforproductssucｈas　glａsｓorpｌasｔicｓarｅalｓoexｃludｅｄｆｒom　ｃoveraｇeby　thiｓ　definitｉon.

TransｆｏrmatioｎCurｖｅｓ

Ｔhe　baｓisｆoｒheattrｅatｍｅntistｈetiｍe—tempeｒature—ｔraｎsformaｔion　cuｒｖes　orTTTcｕrveswｈere，ｉn　ａｓingleｄiagram　ａlｌthethｒeｅｐarameｔeｒsaｒeplotted.Ｂｅcauseｏftheshapeｏｆthecurves，tｈey　arealsｏsomeｔｉｍeｓcalｌedC—cｕｒｖes　orＳ－curｖes.

To　plotTＴTcurｖes，ｔｈｅpａrｔicｕｌarｓteelisheｌｄａtagivｅnteｍｐerａtｕｒeanｄthｅstｒuctuｒeｉsexaｍiｎed　at　pｒedeteｒminedintervalstoｒecoｒdtheaｍoｕntoftｒansformatiｏn　ｔａｋen　pｌａｃe.Itiｓknown　tｈat　the　eutectoｉdstｅeｌ（T８０）ｕnｄer　equilibｒiumconditｉons　contains，aｌl　aｕsteniteabove72３℃,ｗｈereas　ｂelｏｗ，iｔisthepearlite。

Toformpearlite,thｅｃaｒbonａtoms　should　dｉｆfuｓetｏformcemｅntite。

Ｔheｄｉfｆusion　beinｇ　aｒatｅ　proｃesｓ,wouldreqｕｉresufficienｔ　tiｍefｏr　completetransfoｒｍatｉoｎoｆaｕsteniｔetopｅarlｉte．Froｍｄiffereｎｔｓaｍplｅs，itiｓpｏssible　ｔo　nｏtｅ　the　amｏuntoｆｔhetｒaｎｓforｍａtｉoｎ　tａkinｇplace　atanyｔeｍperature.Theｓeｐointｓarｅｔhenplotteｄonagraphｗitｈtiｍeaｎdtｅｍpeｒaturｅ　ａｓ　thｅaxeｓ。

Thｒoughthｅｓepｏiｎts，ｔransｆormationcurvescanbeplottｅdaｓshownｉｎ　Fig．1　forｅuｔectｏidsｔeｅl.Tｈeｃurｖｅａｔｅｘｔｒeme　ｌeftrｅpｒesentstｈetｉmeｒeｑｕiredfｏrｔhetｒansfoｒmatioｎofａusteniｔetoｐearｌitetｏｓtaｒｔatany　ｇiventemｐｅrature．Similarly,theｃuｒｖｅ　at　eｘｔremerightｒｅpｒｅsents　thetiｍerequiredｆorcomplｅｔing　ｔhｅtrａnｓformａtｉｏn．Betweenthｅtｗoｃuｒvesarethepｏｉｎtsreｐresentingｐartｉaltransfｏrmａtion.TｈehorｉzontalｌｉｎesＭsandMfrepresenｔtheｓｔart　andfiｎiｓhof　martenｓitictraｎsfｏrmａtｉoｎ.

Claｓsｉfication　of　Heaｔ　Tｒｅatｉng　Prｏcｅsses

In　ｓomeinstances,hｅattreatｍentｐrocedurｅs　areｃleａr－cutiｎｔｅrmsｏf　techniqueandaｐpｌicatｉｏn．whｅreasin　otheｒinsｔances,ｄｅscriptiｏnsorｓｉmpleexplａnａtions　areiｎｓufficientbecausethesamｅｔecｈniｑuｅｆreqｕently　maｙbeｕsed　to　oｂtaindiｆferenｔｏｂｊｅctiｖes。

Forexａmｐle，sｔress　ｒｅlieviｎgand　temperinｇaｒｅoftｅｎａcｃomplｉshed　wiｔh　the　sameequipmｅntaｎd　ｂｙuseofidentical　timeaｎdtemperaturｅcyｃleｓ。

Ｔheobjeｃtivｅs,ｈowever,aredｉfferentfoｒthetwoｐｒocｅssｅs．

Ｔｈefollowingdescriptionsofthe　princiｐａｌheattreatｉngprocesｓesaregeneralｌyaｒrangｅd　acｃｏrding　totheｉrinterrelａtｉoｎshiｐs.

Ｎｏｒmalｉzｉnｇconsｉstsofheatiｎgaferrｏuｓallｏytｏ　a　suｉtabletemｐerａｔuｒe（usuａlly　50°Ｆｔo　10０°Fｏr　28℃　tｏ56℃）aｂoveｉtsspecｉｆicupｐｅｒtｒansfｏrmaｔioｎtemperaｔｕre.Ｔhiｓisｆollｏwedｂycoｏｌinｇiｎ　ｓtillairtoatleastsomｅtemperatureｗｅｌｌbelｏwiｔstransformatｉoｎ　ｔempeｒaｔure　raｎｇe．Fｏrlow—carbｏnｓteels，the　rｅsultinｇsｔｒucture　aｎｄpｒｏpeｒｔiｅsarethesaｍｅａsthoseachievedｂyfuｌlaｎnealｉng;fｏrmostｆｅrrousａｌloys,noｒｍalｉziｎgand　ａnnealinｇareｎotsｙnonymouｓ.

Normalｉzingｕsｕalｌyisusedasａ　condｉｔioｎinｇtreａtｍent，nｏtabｌyfor　rｅfinｉnｇ　thｅ　grａinsofsteels　ｔhathａvebeｅnｓubjeｃtedto　highｔeｍperａturｅsfoｒｆorｇingorotheｒhoｔ　workiｎgoｐerａｔions.The　ｎｏrmaliｚinｇｐroceｓｓusｕaｌlｙ　iｓsｕcceedｅd　ｂy　ａnoｔheｒheattｒeａｔing　operａtioｎsｕchasaustｅnitizinｇforhardeｎｉng，annｅaｌiｎg，　orｔemperiｎg.

Aｎnｅaliｎｇ　ｉsa　ｇenｅriｃｔｅrmdenｏtiｎgaheａtｔreａtmenｔthaｔconsistｓofｈeatiｎg　ｔoandhｏlding　ａtaｓuiｔable　temperature　folｌowedbycoolingat　asuiｔabｌerate。

Iｔis　uｓeｄｐrimaｒilｙｔosｏfｔｅnmetａllｉcmateriaｌｓ，butalｓoｔosimultaneousｌyproducedesireｄｃhaｎgesｉｎ　otheｒ　ｐropeｒtiesoｒin　micrｏstrｕctｕｒe.Thepurposｅofsuchｃｈangesmaybｅ，buｔis　noｔconfｉnｅdto,impｒovement　oｆｍａchinａbｉｌiｔy，fａｃiliｔａtion　ofcoldｗｏrk（knoｗnasin-proｃess　anｎealing），　ｉmｐroveｍｅnｔ　oｆmecｈanicaｌ　orelectrｉcalpｒｏｐeｒｔiｅs,orｔｏ　increase　dimenｓｉonal　stabｉlity.When　apｐliedsolｅlytoreliｖesｔrｅｓseｓ，iｔ　ｃommoｎｌyiｓ　callｅdstｒess-rｅｌiefａnnｅａｌing，synonymouswithstreｓsrｅｌieviｎg．

Whenthｅteｒm“anneａｌｉng”ｉsapplｉed　to　ferrousａlｌoys　ｗｉｔhoutqualifiｃaｔion,fｕlｌ　anｎeaｌiｎｇisapｐｌieｄ。

Thisｉsacｈieｖｅdbｙ　ｈeａｔingabovetｈeaｌloy’stranｓformａtiontｅmpｅrａtuｒe,thenapplying　acoolｉngｃyclｅｗｈiｃh　ｐrｏｖides　mａxｉmｕmsｏftness.　Ｔｈｉscycｌeｍayvarywidely,dｅpenｄｉｎgｏn　comｐｏｓitionaｎｄcharacteristicｓｏfthe　spｅcificalｌoｙ。

Qｕｅnchingｉsarapｉdcooliｎｇof　asteｅloｒalloy　froｍ　the　auｓtenitizｉｎgtempeｒatuｒe　ｂyiｍmｅrｓingthｅｗorkpieｃe　iｎａliqｕiｄｏｒgaｓｅｏusmedｉuｍ．Quenｃhｉngmediｕm　cｏｍmonly　usedincludｅ　waｔer，5%ｂｒinｅ，5％ｃauｓtｉcin　ａnaqueoussoｌuｔion，　ｏｉl，　pｏlymｅr　solutionｓ,or　ｇas（usuallyaiｒornitｒｏgeｎ）。

Ｓelｅｃtiｏnoｆaquencｈｉng　ｍediumｄependsｌargeｌyoｎ　ｔｈe　hardｅｎability　ofmaterｉaｌａnｄthe　massoｆtｈe　materｉalbeingtreatｉnｇ（ｐｒｉｎciｐａllysｅcｔｉonthicknesｓ）．

Thｅ　coolｉngcａpaｂiliｔies　ｏfthe　abｏve－lｉstedqueｎchiｎg　ｍediavary　ｇrｅatly。

In　selｅctｉｎgaqｕenchiｎgmｅdｉｕm，itiｓｂｅｓtｔoaｖoiｄasolutｉon　thaｔhasmore　coｏliｎｇ　ｐower　thanｉsｎeedeｄ　ｔoachieｖｅｔhｅrｅｓuｌts,ｔｈusmiｎimｉzｉng　the　ｐossibilｉtｙofcｒackｉnｇaｎｄ　wａrpｏf　theparts　beinｇ　tｒeaｔeｄ。

　Modifiｃaｔｉｏnsofthetermqｕeｎcｈingｉnclｕｄｅdｉrectqｕenｃhｉｎg,fogqｕenchｉng,hotqueｎching,interrｕｐtedquｅncｈiｎg,　sｅlｅctivｅquenchｉng,ｓpraｙ　quenchｉng,ａnd　timequeｎcｈiｎg。

Tｅmpｅring.Ｉn　hｅatｔreａtingofferrｏusalｌoｙs，ｔeｍperingｃｏｎsistsｏfｒehｅａｔingthe　auｓtｅniｔizeｄ　ａndquenｃｈ－ｈardenedsteeloｒirontoｓoｍｅpｒesｅlｅcteｄteｍperａtｕreｔhatｉs　bｅlｏwthｅloｗerｔrａｎsｆormaｔｉon　tempeｒatuｒe（generａllybelｏw13０0℃oｒ７０5℃）．Tｅmpｅrｉngｏfｆeｒs　a　meａnｓofobｔainingｖａrｉouｓcｏmｂinationｓ　of　mｅｃｈaniｃaｌ　ｐroｐerties.Ｔｅmpeｒｉngteｍperaｔｕreｓｕsedforhａrｄeneｄsｔeelｓare　often　ｎｏ　hiｇheｒthan　300℃（1５0℃）．Ｔhｅterm“temperｉng”shouｌdnot　bｅconfuｓedｗitｈeiｔherprocessaｎneａlｉｎgorstrｅssreliｅving。

Eｖenthoughtimeanｄtempｅrａtuｒecｙcｌes　fｏrtｈe　three　prｏcｅsseｓｍayｂｅtｈeｓame，the　condiｔionsoｆ　themａtｅrialsbｅinｇprocｅssed　and　the　obｊecｔives　mａybediffeｒｅnt。

Sｔrｅss　relieviｎg。

Liｋetempｅriｎg,ｓtｒｅｓsrelieviｎｇis　alｗaysｄonｅｂyheａtinｇｔoｓomeｔemｐｅraturebelｏw　ｔhe　ｌowｅrtraｎsｆoｒmａｔｉontemperatureforsｔeeｌs　andｉronｓ．　Forｎonferｒoｕs　metalｓ，ｔｈｅｔemperatｕrｅ　mayvaｒｙｆrom　sｌｉgｈtly　aｂoveroomtemperaturｅtoｓeｖerａl　ｈunｄｒed　degｒｅes，ｄｅpｅndｉnｇon　tｈｅａｌloyaｎdｔheaｍoｕntofstress　ｒeliefthatｉsdesｉｒed.

Theprｉmary　ｐurposeoｆsｔｒessreｌｉｅviｎｇisｔoｒelievestresｓｅstｈathavebｅeｎｉmpａrｔeｄtotｈewｏｒkpiecefrom　suｃhｐrｏceｓｓesas　fｏrmｉng,　rolｌing，maｃhining　or　ｗeldiｎｇ．Ｔhe　usuａl　pｒocedｕreisto　hｅat　workｐiｅcetｏthe　pre—estａblisｈeｄteｍｐeratｕre　lｏngenoughｔoreｄucetherｅｓｉdｕａlstｒｅｓsｅs　（ｔｈisｉsａtime－aｎdtemｐeraｔuｒe-depenｄｅｎtｏｐeratiｏｎ）　ｔoaｎacceｐtaｂleｌeveｌ；thｉsis　ｆｏllｏｗeｄ　ｂｙ　coｏlｉngat　areｌatｉveｌyslowrate　toａvｏidcreａtiｏnofnｅｗstｒessｅs.

Ｔhｅgeneｒallｙaccepteddeｆiniｔion　ｆorheat　tｒeaｔiｎｇ　ｍeｔals　andmetalaｌloysｉs　“heatingaｎdcooｌｉnga　solidｍｅtａｌｏr　aｌloｙ　ina　ｗａysoastoｏbｔainｓpecｉfiｃconditionsorpｒopｅrtｉｅs.”Heatｉng　for　thesolepurposeｏf　ｈot　worｋｉnｇ（ａs　in　forｇｉng　operations）isexcludｅdfromthis　ｄｅｆｉnition．Liｋｅwｉse，ｔｈetｙｐeｓ　ofhｅatｔrｅatmentthaｔａｒesoｍｅtiｍes　useｄ　forproductssuｃhaｓｇlass　orplａｓｔｉcsarealｓo　ｅｘｃluded　frｏmｃoveｒaｇeｂyｔhｉsdefinｉｔioｎ．

Transforｍation　Ｃｕrｖes

Ｔhｅbaｓisforｈeattｒｅatment　isthe　ｔime—tｅmｐeratuｒe-tranｓｆorｍａtioncurｖeｓorTＴT　ｃuｒves　where，inaｓiｎgle　diagramall　tｈｅｔhreepａramｅterｓareｐloｔted．Becａuseofthe　ｓｈａpeofｔhe　curves,theyarealsosomｅtimescaｌleｄC—curｖｅs　or　S—curvｅｓ．

Topｌot　TTＴcurves,theｐarｔicularsteeliｓｈeｌdａta　giveｎtemｐｅｒａtuｒeanｄthestrucｔurｅｉs　eｘａmineｄatpredetermiｎediｎtｅrvalｓ　torecｏrdｔhｅaｍountoftrａnｓforｍatioｎ　takeｎplａce．Ｉｔｉｓknownthattheeuｔectoidｓtｅel（Ｔ8０）underequilｉbriuｍconditioｎscontaｉns,ａｌl　austeniteaｂove723℃,ｗherｅasbelｏw，it　ispearlｉte.Ｔoform　peａrlｉｔe，thｅ　cａｒｂon　atoｍｓ　ｓｈouｌdｄｉｆfｕse　toｆormcｅmenｔitｅ。

Thediｆfusioｎｂeiｎg　aratｅprocess，wouldｒequｉresｕfｆｉcieｎｔtiｍefor　ｃoｍpletetransfoｒmａtionｏfａusｔｅnitｅto　ｐearliｔe.Fromｄiｆferｅnｔsampleｓ，itispｏssibleｔo　noteｔheamｏｕntofthｅ　ｔranｓｆormation　taｋingpｌacｅataｎｙtｅｍpeｒaturｅ．Ｔhｅsｅｐointｓ　are　ｔｈｅｎ　ploｔtedonａgrａpｈ　with　timeanｄtemｐeｒaturｅaｓ　thｅaxes。

Ｔhｒoｕgh　tｈesepoinｔs，traｎsforｍaｔｉoncurvescan　be　plｏtｔedas　ｓhowninＦig．１foｒeutectoid　steel．Ｔhe　cｕrvｅaｔexｔｒemeleｆtreｐｒesｅntｓthetimerｅquiｒｅdforthｅtransformatｉｏn　oｆauｓteniｔetopｅarliｔｅ　to　ｓtartａtaｎygｉvｅntempｅｒature．Siｍｉｌａrly，thecurvｅａｔeｘtｒemerightｒｅｐrｅsenｔsthetimeｒequｉrｅdfor　cｏmpletingtｈｅtrａnｓformation。

Ｂeｔweenthｅtｗo　ｃｕｒveｓaretｈｅ　pointsrepｒｅｓｅnｔingparｔial　transformation。

Thehoriｚoｎｔａl　ｌinesＭs　anｄMｆ　repｒesｅｎｔthｅ　startanｄ　fｉniｓhｏfmartensitic　ｔransforｍatｉoｎ.

CｌａｓsificationｏfHeatTreaｔinｇPrｏｃｅｓｓes

Ｉn　sｏｍeinstaｎcｅｓ，heaｔtreatｍｅntpｒoceｄｕｒesaｒecleａｒ－cｕｔiｎterｍsoftechｎiqｕeanｄ　aｐplicａtion．whｅrｅasinｏｔher　instances，descriｐｔiｏｎs　orsimple　eｘｐｌanａtionｓareinsｕfficiｅｎtbecause　ｔhｅ　saｍetechniquｅfrｅquenｔlymayｂeuｓｅdｔoｏbtａindifｆereｎt　objecｔｉｖｅs.Forexample，　ｓtrｅsｓｒelieving　ａｎdteｍperingａｒeｏftｅnaccｏmpｌiｓhｅｄ　ｗithｔhe　saｍe　equｉｐmeｎtａndbyuｓe　ofidenｔicａltime　andtemperaｔurecｙcｌｅs．Thｅoｂjｅｃtｉves，hｏｗever,areｄiｆferentfoｒ　ｔｈetｗｏprｏcessｅs．

Theｆollowｉｎgdeｓcrｉｐtｉons　ofｔhepｒｉncipal　heaｔtreatｉｎgprocesses　ａregｅneｒally　ａrrangｅdａccoｒdingtoｔheiｒ　inｔerrelationsｈips。

Nｏｒｍaliｚingconｓistsofｈeatingａfeｒrｏusallｏytoasuiｔabｌetemperaｔure　（usually50°Ftｏ1０0°F　or2８℃tｏ56℃）aboveiｔsｓpｅcifiｃuppｅrtrａnsforｍatioｎtemｐeratuｒe．Tｈisｉｓfollowedbycoｏliｎginstilｌ　ａiｒ　toａtleastsomeｔemperatｕreｗｅllｂelｏｗits　transfｏrmatiｏnｔｅmpeｒature　rａnge．Ｆor　low－cａrbonsｔeelｓ,ｔherｅsulting　stｒｕctureａndproperｔiesare　thesaｍeａsthoseachieved　byfull　aｎnｅａlinｇ；ｆor　mｏstferｒous　allｏys，normａliziｎgａnｄaｎnｅａliｎg　arenotsynｏnymoｕs.

Normaliziｎg　usuallｙisuseｄasa　conditioｎiｎg　treatmeｎｔ，nｏtably　forrefiniｎｇtheｇrainｓofsteelｓｔhat　havebeensubjecteｄ　tｏhightemperatuｒesforfoｒgingｏrotheｒhoｔｗoｒkingoperａtｉｏns。

Thenormａlｉzingprｏcesｓｕｓuａlｌy　is