鋼鐵熱處理中英文對照外文翻譯文獻(xiàn)

外文資料原文與譯文中英文對照外文翻譯(文檔含英文原文和中文翻譯)原文:HeatTreatmentofSteelTypesofHeatTreatingOperationsFiveOperationsaredetailedinthislessonasthebasisofheattreatment.Explanationsoftheseoperationsfollow.FullannealingFullannealingistheprocessofsofteningsteelbyaheatingandcoolingcycle,sothatitmaybebentorcuteasily.Inannealing,steelisheatedaboveatransformationtemperatureandcooledveryslowlyafterithasreachedasuitabletemperature.Thedistinguishingcharacteristicsoffullannealingare:(a)temperatureabovethecriticaltemperatureand(b)veryslowcooling,usuallyinthefurnace.NormalizingNormalizingisidenticalwithannealing,exceptthatthesteelisaircooled;thisismuchfasterthancoolinginafurnace.Steelisnormalizedtorefinegrainsize,makeitsstructuremoreuniform,ortoimprovemachinability.HardeningHardeningiscarriedoutyquenchingasteel,thatis,coolingitrapidlyfromatemperatureabovethetransformationtemperature.Steelisquenchedinwaterorbrineforthemostrapidcooling,inoilforsomealloysteels,andinairforcertainhigheralloysteels.Aftersteelisquenched,itisusuallyveryhardandbrittle;itmayevencrackifdropped.Tomakethesteelmoreductile,itmustbetempered.TemperingTemperingconsistesofreheatingaquenchedsteeltoasuitabletemperaturebelowthetransformationtemperatureforanappropriatetimeandcoolingbacktoroomtemperature.Howthisprocessmakessteeltoughwillbediscussedlater.StressrelievingStressrelievingistheheatingofsteeltoatemperaturebelowthetransformationtemperature,asintempering,butisdoneprimarilytorelieveinternalstressandthuspreventdistortionorcrackingduringmachining.Thisissometimescalledprocessannealing.ReasonsforHeatTreatingHeattreatmentofsteelisusuallyintendedtoaccomplishanyoneofthefollowingobjectives:Removestressesinducedbycoldworkingortoremovestressessetupbynonuniformcoolingofhotmetalobjects;Refinethegrainstructureofhotworkedsteelswhichmayhavedevelopedcoarsegrainsize;Securethepropergrainstructure;Decreasethehardnessandincreasetheductility;Increasethehardnesssoastoincreaseresistancetowearortoenablethesteeltowithstandmoreserviceconditions;Increasethetoughness;thatis,toproduceasteelhavingbothahightensilestrengthandgoodductility,enablingittowithstandhighimpact;Improvethemachinability;Improvetheelectricalproperties;Changeormodifythemagneticpropertiesofsteel.HeatTreatmentThehardestconditionforanygivenssteelisobtainedbyquenchingtoafullymartensiticstructure.Sincehardnessisdirectlyrelatedtostrength,asteelcomposedof100%martensiteisatitsstrongestpossiblecondition.However,strengthisnottheonlypropertythatmustbeconsideredintheapplicationofsteelparts.Ductilitymaybeequallyimportant.TemperingDuctilityistheabilityofametaltochangeshapebeforeitbreaks.Fleshlyquenchedmartensiteishardbutnotductile;infact,itisverybrittle.Temperingisneededtoimpartductilitytothemartensite,usuallyatasmellsacrificeinstrength.Inaddition,temperinggreatlyincreasestheresistanceofmartensitetoshockloading.Theeffectoftemperingmaybeillustratedasfollows.Iftheheadofahammerwerequenchedtoafullymartensiticstructure,itprobablywouldcrackafterthefirstfewblows.Temperingduringmanufactureofthehammerimpartsshockresistancewithonlyaslightdecreaseinhardness.Temperingisaccomplishedbyheatingaquenchedperttosomepointbelowthetransformationtemperature,andholdingitatthistemperatureforanhourormore,dependingonitssize.Moststeelsaretemperedbetween205and5,950C.Ashighertemperaturesareemployed,toughnessorshockresistanceofthesteelisincreased,butthehardnessandstrengthdecrease.Annealingthetwo-stageheattreatingprocessofquenchingandtemperingisdesignedtoproducehighstrengthsteelcapableofresistingshockanddeformationwithoutbreaking.Ontheotherhand,theannealingprocessisintendtomakesteeleasiertodeformofmachine.Inmanufacturingsteelproducts,machiningandseverebendingoperationsareoftenemployed.Eventemperedsteelmaynotcutorbendveryeasilyandannealingisoftennecessary.ProcessannealingProcessannealingconsistsofheatingsteeltoatemperaturejustbelowthelowesttransformationtemperatureforashorttime.Thismakesthesteeleasiertoform.Thisheattreatmentiscommonlyappliedinthesheetandwireindustries,andthetemperaturesgenerallyusedarefrom550to650oC.FullannealingProcessannealing,wheresteelisheated50to100oCabovethethirdtransformationtemperatureforhypoeutectoidsteels,andabovethelowesttransformationtemperatureforhypereutectoidsteels,andslowcooled,makesthesteelmucheasiertocut,aswellasbend.Infullannealing,coolingmusttakeplaceveryslowlysothatacoarsepearliteisformed.Showcoolingisnotessentialforprocessannealing,sinceanycoolingratefromtemperaturesbelowthelowesttransformationtemperaturewillresultinthesamemicrostructureandhardness.Duringcolddeformation,steelhasatendencytohardenindeformedareas,makingitmoredifficulttobendandliabletobreakage.Alternatedeformingandannealingoperationsareperformedonmostmanufacturedsteelproducts.NormalizingTheprocessofnormalizingconsistsofheatingtoatemperatureabovethethirdtransformationtemperatureandallowingtheperttocoolinstillair.Theactualtemperaturerequiredforthisdependsonthecompositionofthesteel,butisusuallyaround870oC.Actually,thetermnormalizedoesnotdescribethepurpose.Theprocessmightbemoreaccuratelydescribedasahomogenizingorgrain-refiningtreatment.Withinanypieceofsteel,thecompositionisusuallynotuniformthroughout.Thatis,oneareamayhavemorecarbonthantheareaadjacenttoit.Thesecompositionaldifferencesaffectthewayinwhichthesteelwillrespondtheattreatment.Ifitisheatedtoahightemperature,thecarboncanreadilydiffusethroughout,andtheresultisareasonablyuniformcompositionfromoneareatonext.Thesteelisthenmorehomogeneousandwillrespondtotheheattreatmentinamoreuniformway.Becauseofcharacteristicsinherentincaststeel,thenormalizingtreatmentismorefrequentlyappliedtoingotspriortoworking,andtosteelcastingsandforgingspriortohardening.StressRelievingWhenametalisheated,expansionoccurswhichismoreorlessproportionaltothetemperaturerise.Uponcoolingmetal,thereversereactiontakesplace.Thatis,acontractionisobserved.Whenasteelbarorplateisheatedatonepointmorethanatanother,asinweldingorduringforging,internalstressaresetup.Duringheating,expansionoftheheatedareacannottakeplaceunhindered,andittendstodeform.Oncooling,contractionispreventedfromtakingplacebytheunyieldingcoldmetalsurroundingtheheatedarea.Theforcesattemptingtocontractthemetalarenotrelieved,andwhenthemetaliscoldagain,theforcesremainasinternalstresses.Stressesalsoresultfromvolumechanges,whichaccompanymetaltransformationsandprecipitation.Internalorresidualstressesarebadbecausetheymaycausewarpingofsteelpartswhentheyaremachined.Torelievethesestresses,steelisheatedtoaround595oC,assumingthattheentirepertisheateduniformly,thencooledslowlybacktoroomtemperature.Thisprocedureiscalledstressreliefannealing,ormerelystressrelieving.

譯文：鋼的熱處理各種類型的熱處理本單元詳細(xì)介紹了五種熱處理的基本方法。這些方法如下。完全退火完全退火是利用冷熱循環(huán)使鋼鐵硬度下降的過程，之后它就容易被切割和彎曲。在退火時(shí)，鋼被加熱到相變溫度上并且達(dá)到一個(gè)合適溫度后就緩慢冷卻。完全退火的區(qū)別其他退火的特點(diǎn)是：（a）溫度高于臨界溫度（b）緩慢冷卻，通常是爐冷。正火正火與退火相同，除了鋼鐵的正火是空冷，這樣將比在爐中冷卻的快。金屬進(jìn)行正火是為了細(xì)化精粒，使它的組織更加規(guī)律，或提高它的機(jī)械加工性能。淬火淬火就是鋼淬火，它是將鋼從臨界溫度以上迅速冷卻。鋼一般是在水中或者鹵水中進(jìn)行淬火，這是為了快速冷卻，而另外一些合金鋼用油冷，以及某些高等合金鋼要用空冷。鋼催后之后，一般會很硬很脆，有可能在落地后碎裂。為了是鋼有更高的韌性它，必須還要經(jīng)過回火回火回火是將淬火過的鋼再次加熱到轉(zhuǎn)變溫度以下一定時(shí)間后再冷卻到室溫的熱處理工藝。這個(gè)過程是如何使鋼有高硬度之后將會討論。去應(yīng)力去應(yīng)力是加熱鋼到轉(zhuǎn)變溫度一下，如同回火一樣，但這樣做主要是為了消除內(nèi)應(yīng)力和防止在機(jī)械加工的過程中的扭曲和變形。有時(shí)候我們也稱這個(gè)過程叫做退火。熱處理的原因鋼的熱處理經(jīng)常是為了完善如下幾個(gè)方面：消除在冷卻過程中產(chǎn)生的應(yīng)力和消除熱金屬處理中的應(yīng)力。細(xì)化晶粒組織，鋼可能在熱加工過后會產(chǎn)生粗大的晶粒。獲得穩(wěn)定的適當(dāng)?shù)木Я＝Y(jié)構(gòu)降低硬度，提高塑性。增加硬度以提高抗磨損能力或者使金屬能夠承受更多條件環(huán)境。、增加韌性，這樣一來，可以使鋼同時(shí)擁有高拉伸性和好的延展性，使它能承受高程度的碰撞。提高切削性能。提高導(dǎo)電性。改變鋼的磁性。熱處理對于任何一種鋼而言，最困難的是獲得馬氏體。由于硬度和強(qiáng)度有直接關(guān)系，鋼由百分之百的馬氏體組成時(shí)它處于最大強(qiáng)度狀態(tài)。然而，強(qiáng)度并不是鋼在應(yīng)用中唯一考慮的性質(zhì)，延展性同樣重要?；鼗鹂伤苄允侵附饘僭谄淦屏亚案淖冃螤畹哪芰?。馬氏體本身具有很高硬度但延展性不高，而且易碎?；鼗鹗潜挥米魇柜R氏體具有良好的可塑性，往往是犧牲了一小部分的強(qiáng)度。此外，回火處理大大增加了馬氏體抵抗沖擊負(fù)荷的能力?；鼗鸬挠绊懸韵屡e例說明。如果一個(gè)錘子的頭經(jīng)過淬火變成完全馬氏體的結(jié)構(gòu)，它很可能在最初的幾次打擊后破裂。錘子的韌性在回火過程中獲得提高而僅僅伴隨硬度稍微降低?；鼗鹗墙?jīng)過淬火后急速冷卻到相變溫度下某一點(diǎn)的過程，并且保持這個(gè)溫度一個(gè)小時(shí)或者更久，這個(gè)溫度由鋼的尺寸來決定。大多數(shù)鋼的回火溫度在205℃~595℃。隨著溫度的提高，鋼的韌性和抗沖擊強(qiáng)度也增強(qiáng)，但是硬度和強(qiáng)度下降。退火在回火和淬火這兩個(gè)工藝階段，其目的是能制造可以抵抗高沖擊強(qiáng)度和磨