钢铁热处理中英文对照外文翻译文献

外文资料原文与译文中英文对照外文翻译(文档含英文原文和中文翻译)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.

译文：钢的热处理各种类型的热处理本单元详细介绍了五种热处理的基本方法。这些方法如下。完全退火完全退火是利用冷热循环使钢铁硬度下降的过程，之后它就容易被切割和弯曲。在退火时，钢被加热到相变温度上并且达到一个合适温度后就缓慢冷却。完全退火的区别其他退火的特点是：（a）温度高于临界温度（b）缓慢冷却，通常是炉冷。正火正火与退火相同，除了钢铁的正火是空冷，这样将比在炉中冷却的快。金属进行正火是为了细化精粒，使它的组织更加规律，或提高它的机械加工性能。淬火淬火就是钢淬火，它是将钢从临界温度以上迅速冷却。钢一般是在水中或者卤水中进行淬火，这是为了快速冷却，而另外一些合金钢用油冷，以及某些高等合金钢要用空冷。钢催后之后，一般会很硬很脆，有可能在落地后碎裂。为了是钢有更高的韧性它，必须还要经过回火回火回火是将淬火过的钢再次加热到转变温度以下一定时间后再冷却到室温的热处理工艺。这个过程是如何使钢有高硬度之后将会讨论。去应力去应力是加热钢到转变温度一下，如同回火一样，但这样做主要是为了消除内应力和防止在机械加工的过程中的扭曲和变形。有时候我们也称这个过程叫做退火。热处理的原因钢的热处理经常是为了完善如下几个方面：消除在冷却过程中产生的应力和消除热金属处理中的应力。细化晶粒组织，钢可能在热加工过后会产生粗大的晶粒。获得稳定的适当的晶粒结构降低硬度，提高塑性。增加硬度以提高抗磨损能力或者使金属能够承受更多条件环境。、增加韧性，这样一来，可以使钢同时拥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。提高导电性。改变钢的磁性。热处理对于任何一种钢而言，最困难的是获得马氏体。由于硬度和强度有直接关系，钢由百分之百的马氏体组成时它处于最大强度状态。然而，强度并不是钢在应用中唯一考虑的性质，延展性同样重要。回火可塑性是指金属在其破裂前改变形状的能力。马氏体本身具有很高硬度但延展性不高，而且易碎。回火是被用作使马氏体具有良好的可塑性，往往是牺牲了一小部分的强度。此外，回火处理大大增加了马氏体抵抗冲击负荷的能力。回火的影响以下举例说明。如果一个锤子的头经过淬火变成完全马氏体的结构，它很可能在最初的几次打击后破裂。锤子的韧性在回火过程中获得提高而仅仅伴随硬度稍微降低。回火是经过淬火后急速冷却到相变温度下某一点的过程，并且保持这个温度一个小时或者更久，这个温度由钢的尺寸来决定。大多数钢的回火温度在205℃~595℃。随着温度的提高，钢的韧性和抗冲击强度也增强，但是硬度和强度下降。退火在回火和淬火这两个工艺阶段，其目的是能制造可以抵抗高冲击强度和磨