機(jī)械專業(yè)英語(yǔ)(章躍版)課后英漢翻譯

第一章：應(yīng)力與應(yīng)變Thatbranchofscientificanalysiswhichmotions,timesandforcesiscalledmechanicsandismadeupoftwoparts,staticsanddynamics.研究位移、時(shí)間和力運(yùn)動(dòng)乘力是科學(xué)分析法的一個(gè)分歧，被稱作力學(xué)，力學(xué)由兩大部分組成，靜力學(xué)和動(dòng)力學(xué)。Forexample,iftheforceoperatingonasleevebearingbecomestoohigh,itwillsqueezeouttheoilfilmandcausemetal-to-metalcontact,overheatingandrapidfailureofthebearing.例如：如果止推軸承上的作用力過(guò)大的話，會(huì)擠出油膜，引起金屬和金屬之間的相互接觸，軸承將過(guò)熱而迅速失效。Ourintuitiveconceptofforceincludessuchideasasplaceofapplication,direction,andmagnitude,andthesearecalledthecharacteristicsofaforce.力的直觀概念包括力的作用點(diǎn)、大小、方向，這些被稱為力的三要素。Allbodiesareeitherelasticorplasticandwillbedeformedifacteduponbyforces.Whenthedeformationofsuchbodiesissmall,theyarefrequentlyassumedtoberigid,i.e.,incapableofdeformation,inordertosimplifytheanalysis.所有的物體既可以是彈性的也可以是塑性的，如果受到力的作用就產(chǎn)生變形。當(dāng)變形很小的時(shí)候它們被假設(shè)成剛體，也就是不產(chǎn)生變形。Therigid-bodyassumptioncannotbeusedininternalstressesandstrainsduetotheappliedforcestobeanalyzed.Thusweconsiderthebodytobecapableofdeforming.剛體假設(shè)不能應(yīng)用于內(nèi)應(yīng)力和內(nèi)應(yīng)變的分析，所以在實(shí)際力的分析時(shí)，要考慮物體的形變。Ifalltheforcesactingonaparticlearebalanced,theparticlewilleitherremainatrestorwillcontinuetomoveinastraightlineatauniformvelocity.如果作用在質(zhì)點(diǎn)上所有的力是平衡的，質(zhì)點(diǎn)將會(huì)保持靜止或做做勻速直線運(yùn)動(dòng)。：材料的強(qiáng)度與塑性1.Atensiletestconsistsofslowlypullingasampleofmaterialwithatensileloaduntilitbreaks.Theendsoftensilespecimensareusuallyenlargedtoprovideextraareaforgrip-pingandtoavoidhavingthesamplebreakwhereitisbeinggripped.拉伸試驗(yàn)包括慢慢加載拉伸載荷直到斷裂。拉伸試件兩端加粗為了提供裝夾區(qū)域和避免試件斷裂。Theusualmannerofconductingthetestistodeformthespecimenataconstantspeed.Forexample,intheuniversaltestingmachines,themotionbetweenthefixedandmovingcrossheadscanbecontrolledataconstantspeed.通常進(jìn)行試驗(yàn)的方法就是使試件以恒定速度發(fā)生變形。例如，在萬(wàn)能拉伸試驗(yàn)機(jī)上，固定端和移動(dòng)的十字滑塊之間的變形是以恒定速度進(jìn)行的。Theloadthatmustbeappliedtoenforcethisdisplacementratevariesasthetestproceeds.ThisloadFmaybedividedbythecross-sectionalareaAtoobtainthestressinthespecimenatanytimeduringthetest.隨著實(shí)驗(yàn)的進(jìn)行，用來(lái)產(chǎn)生位移的載荷是隨位移的變化而變化。在實(shí)驗(yàn)中，載荷F除以橫截面積A可以得到任意時(shí)刻點(diǎn)的應(yīng)力。HoweveractualmeasurementofΔLispreferablewherethisisfeasible.Stressandstrainbasedontheinitial(undeformed)dimensions,AiandLi,arecalledengineeringstressandstrain.然而，在可行的位置上ΔL的實(shí)際測(cè)量是更可取的，基于原始尺寸Ai和Li的應(yīng)力和應(yīng)變稱為工程應(yīng)力和工程應(yīng)變。Ductile andbrittlematerialsbehavedifferentlyincompressiontestaswell.Thecompressiontestisconductedonshortcylindricalspecimensplacedbetweenparallelplates.塑性和脆性材料在壓縮試驗(yàn)中表現(xiàn)的特性是不相同的。壓縮試驗(yàn)是把短圓柱形試件放在兩平行平板之間進(jìn)行的。6.Thecompressiontestdiagramforthesematerialsretainsthequalitativefeaturesofthetensiontestdiagram.Theultimatecompressivestrengthofabrittleofabrittlematerialisdeterminedinthesamewayasintension.材料壓縮試驗(yàn)圖保持了拉伸試驗(yàn)圖性能上的特征。脆性材料的最大壓縮強(qiáng)度與最大拉伸強(qiáng)度得到的方法相同。：砂型鑄造1.Thefirststageintheproductionofsandcastingmustbethedesignandmanufactureofasuitablepattern.Castingpatternhastobemadelargerthanthefinishedcastingsizetoallowfortheshrinkagethattakesplaceduringsolidificationandcooling.在型砂鑄造生產(chǎn)中，第一階段是必須設(shè)計(jì)和制造合適的模型，考慮到鑄件在凝固和冷卻期間產(chǎn)生的收縮鑄件模型的尺寸要比鑄件的尺寸大。2.Ifahollowcastingistobemadethepatternwillincludeextensionpiecessothatspacestoacceptthesandcorearemoldedintothesand.Theseadditionalspacesinthemoldaretermedcoreprints.如果鑄造空心鑄件時(shí)模型上包含伸長(zhǎng)桿便于在砂中放置砂芯的空間稱為型芯座。3.Sandmoldsfortheproductionofsmallandmedium-sizedcastingsaremadeinamoldingbox.Themoldismadeintwoormorepartsinorderthatthepatternmayberemoved.中小型尺寸的鑄件砂型是在一個(gè)砂箱中制造，砂型由兩部分或更多部分組成，以利于模型的順利取出。4.Thisprocessoffillingandrammingmaybedonebyhandbutmoldproductionisautomatedinalargefoundrywiththemoldboxesmovingalongaconveyor,firstlytobefilledwithsandfromhoppersandthentopassundermechanicalhammersforramming.填充和夯實(shí)的過(guò)程可以手工完成，但在大型鑄造中砂型的制造是自動(dòng)完成的，砂箱隨著傳送帶移動(dòng)，首先被料斗中的砂子填滿，然后通過(guò)機(jī)械錘時(shí)被打?qū)崱?.Therisersshouldcoincidewiththehighestpointsofthemoldcavitysothatthedisplacedaircanreadilyescapefromthemold.Thesizesofrisersshouldbesuchthatthemetalinthemdoesnotfreezetoorapidly.冒口應(yīng)該與型腔的最高點(diǎn)相連接，使得進(jìn)入的空氣可以容易的從模型中溢出，冒口的尺寸應(yīng)該足夠大使模型中金屬不會(huì)太快凝固。6.Whenthemetalthathasbeenpouredintoasandmoldhasfullysolidified,themoldisbrokenandthecastingisremoved.Thecastingstillhastherunnerandrisersattachedtoitandtherewillbesandadheringtoportionsofthesurface.當(dāng)熔的金屬被傾倒到砂型內(nèi)并充分凝固以后，砂型將被打破取出鑄件，鑄件上依然帶有橫澆口和冒口并且依然有砂子粘在表面。電弧焊1.arcweldinginoneformoranotheristhemostwidelyusedformofwelding.theelectricalsupplyislowvoltagebuthighamperageandmaybeeitheralternatingordirect.電弧焊在一種或另一種形式是應(yīng)用最廣泛的焊接形式。電力供應(yīng)是低電壓，但是大電流，并且可以是交流或直流。theearliestformsofarcweldingusedcarbonelectrodes.butnowadaysthearcisstruckbetweenametalelectrodeandwork-piece.theelectrodemayeitherbeoftungstenorbeaconsumablemetalelectrodethatmelts,actingasasourceoffillermetal.電弧焊接的最早的形式使用碳電極，但現(xiàn)在的電弧觸發(fā)一個(gè)金屬電極與工件之間，電極可以是鎢或可熔化，作為填充金屬供源的消耗性金屬電極。analternating-currentarcisbrokenandre-establishedateachhalfcycleandthisleadstoarcinstabilityalthoughtheuseofarc-establishedagentsinthefluxcoatingofelectrodewirescanovercomethisproblem.交流電弧被打破并且重新建立在每個(gè)半周期，這導(dǎo)致電弧不穩(wěn)定雖然在電極布線焊劑涂層使用電弧建立劑可以克服這個(gè)問題。uncoatedweldingrodscanbeusedforarcwilding.butitismoreusualtouseflux-coatedelectrodes.whensteelsareweldedusinguncoatedelectrodes,oxidesandnitridescanformandremainintheweldwithaconsequentlossoftoughness.未涂覆的焊條可以用于電弧野生植物。但更通常使用的焊劑涂覆的電極。當(dāng)鋼在使用未涂覆的電極焊接，氧化物和氮化物能夠形成并保持在焊縫韌性因此而喪失。flux-coatedelectrodesarewidelyused.thecompositionofthecoatingsiscomplexandavarietyofdifferentcoatingsareusedtocaterfordifferenttypesofweldingapplication.焊劑涂覆的電極被廣泛使用。涂層的組成是復(fù)雜和各種不同的涂料是用于配合不同類型的焊接應(yīng)用。inthiscasetheelectronflowisfromelectrodetowork-piece.Aconcentratedarcissuesfromtheelectrodetipandheatingofthework-pieceislargelyconfinedtotheverysmallaresbeneaththeelectrode.在這種情況下電子流動(dòng)是從電極到工件，從電極頭和工件的加熱濃縮的弧的問題在很大程度上僅限于電極下方的非常小頃。第十章：鋼1.Insimpleterms,aplaincarbonsteelmaybesaidtobeanalloyofironandcarboncontaininglessthan1.7%carbon.Inpractice,however,thesesteelsrarelycontainmorethan1.4%carbonandotherelementsarealsopresent,eitherasdeliberateadditions(e.g.manganese)orasimpurities(e.g.sulphurandphosphorus).簡(jiǎn)單來(lái)說(shuō)，普通碳素鋼也被稱為含碳量少于1.7%的合金鋼。然而事實(shí)上，這些鋼材中很少有含碳量多于1.4%，同時(shí)也含有其它元素，例如一些額外添加物（如錳）或者雜志（如硫和磷）。2.Inthemanufactureofthismaterial,completedeoxidationisnotcarriedoutanditismadeasrimmingsteel.Itisproducedashotandcoldwordedsheet,strip,rod,wireandtube,andisavailableinthehot-workedorprocessannealedcondition.在材料的生產(chǎn)加工中，不能實(shí)現(xiàn)脫氧還原反應(yīng)的鋼被稱為沸騰鋼。它被用來(lái)生產(chǎn)熱處理或冷處理的薄片、帶、棒、電線、和管，并且它適用熱軋和退火的情況下。3.Thestrengthandhardnessofthesesteelislow,butahardsurfacecanbeobtainedbycarbursinginordertocombineawear-resistantsurfacewithtoughcoreproperties.鋼的強(qiáng)度和硬度低，可以通過(guò)滲碳的方法獲得表面硬化以達(dá)到表面耐寒內(nèi)部韌性較好的特性。4.Asthecarboncontentisraisedabove0.2%,thestrengthincreasesintotherangerequiredforconstructionalpurposes,buttheductilitydecreases.Thefabricationqualities(workingandweldingcharacteristics)ofthismaterialareverygood.一旦鋼中含碳量上升超過(guò)0.2%，結(jié)構(gòu)上的強(qiáng)度會(huì)發(fā)生巨大變化，但是其延展性會(huì)下降。材料的制造質(zhì)量（承載和焊接特性）非常好。5.Mediumcarbonsteelsareoftenquenched-hardenedandfullytemperedtogivegoodstrengthwithmaximumtoughness,whicharethepropertiesrequiredofcomponentssuchasshafts,gearsandconnectingrods.中碳鋼常被淬火硬化和高溫回火處理以便給予良好的溫度和最大的韌性，這些是軸、齒輪和連桿所要求的能力特性。6.Highcarbonsteelsarequenchhardenedandlightlytemperedtogivehighhardnesswithonlylimitedtoughness.Materialinthisclassificationismainlyusedformakingfairlysmall,relativelyinexpensivecuttingtoolssothatthegroupasawholeisknownascarbontoolsteel.高碳鋼常被淬火硬化和低溫回火處理以便給予高硬度和一定韌性。此類材料主要被用于生產(chǎn)相當(dāng)小、可靠地、廉價(jià)的切削工具，者這就是碳素工具鋼。：金屬熱加工Theprincipalkindsofheat-treatmentusedinpractice.whichdifferentlyaffectthestructureandproperties,andwhichareassignedtomeettherequirementsmadetothesemifabricatedmaterials(castingsforgings,rolledstock,etc.)andfinishedarticles:are(1)annealing;(2)normalizing;(3)hardeningand(4)tempering.所用的主要種類熱處理的做法，以不同方式影響結(jié)構(gòu)和性能，并分配給滿足于半加工材料制成的要求（鑄件鍛件，軋材等）和必要的類型：是（1）退火（2）正火，（3）淬火和（4）回火。Normalizingraisesthestrengthandhardnessofmediumandhigh-carbonsteelsby10to15percentascomparedtoannealedsteel.正火引起較退火的鋼的強(qiáng)度和中等和高碳鋼硬度由10至15％。Martensiteisveryhardandbrittle,havingamuchhighertensilestrengththanthesteelwithapearlitemicrostructure.馬氏體是非常硬且脆的，具有高得多的抗張強(qiáng)度比鋼具有珠光體組織。Tempering,ordrawing,isaprocessofreheatingasteelpartthathasbeenpreviouslyhardenedtotransformhardmartensiteintosofterstructure.thehigherthetemperingtemperatureused,thesofterandtougherthepiecebecomes.回火，或圖中，是再加熱先前已硬化改造硬馬氏體成較軟的結(jié)構(gòu)的鋼部件的工藝?；鼗饻囟戎惺褂玫妮^高，較軟及更嚴(yán)格的片而成。Forlowcarbonsteels,normalizingenablesabettersurfacefinishtobeobtainedinmachiningandraisetheproductioncapacity.對(duì)于低碳鋼，正火使得能夠在加工得到更好的表面光潔度，并提高生產(chǎn)能力。Incommercialtemperingthetemperaturerangeof250-425℃isusuallyavoidedbecauseofanunexplainedembrittlement,orlossofductility,thatoftenoccurswithsteelstemperedinthisrange.在商業(yè)回火250-425℃的溫度范圍通常是可以避免的，因?yàn)橐环N原因不明的脆化，或延展性的損失，經(jīng)常發(fā)生回火鋼在此范圍內(nèi)。第二十章：數(shù)控技術(shù)Numericalcontrolmeansthecontrolofmachinetoolsandothermanufacturingsystemsthroughtheuseofprerecorded,writtensymbolicinstructions.Ratherthanoperatingamachinetool,anNCtechnicianwritesaprogramthatissuesoperationalinstructionstothemachinetool.數(shù)字控制手段控制的機(jī)床和其他制造業(yè)通過(guò)系統(tǒng)的使用做,書面象征性指示。而於操作機(jī)床、NC技術(shù)員寫一個(gè)程序問題業(yè)務(wù)指示機(jī)工具。Likesomanyadvancedtechnologies,NCwasborninthelaboratoriesoftheMassachusettsInstituteofTechnology.TheconceptofNCwasdevelopintheearly1950withfundingprovidedbytheU.S.AirForce.象許多先進(jìn)技術(shù)，數(shù)控出生在馬薩諸塞的實(shí)驗(yàn)室技術(shù)Institude。數(shù)控的概念在早期1950年被開發(fā)了與資助由美國(guó)空軍提供。Thisproblemledtothedevelopmentin1959oftheAutomaticallyProgrammedTools(APT)language.ThisisaspecialprogramminglanguageforN/CthatusesstatementssimilartoEnglishlanguagetodefinethepartgeometry,describethecuttingtoolconfiguration,andspecifythenecessarymotions.這個(gè)問題在1959年導(dǎo)致了發(fā)展刀具控制程序自動(dòng)編制系統(tǒng)中(APT)語(yǔ)言。這是使用聲明相似的N/C的一種特別編程語(yǔ)言對(duì)定義部分幾何的英文，描述切割工具配置，并且指定必要的行動(dòng)。4.N/Cmachinestoolelementsconsistofdimensioningsystems,controlsystems,servomechanismsandopen-orclosed-loopsystems.數(shù)控機(jī)床元素有尺寸體系、控制系統(tǒng)、伺服結(jié)構(gòu)和開環(huán)或閉環(huán)系統(tǒng)組成。Continuous-pathmachinesaremoreexpensivethanpoint-to-pointsystemandgenerallyrequireacomputertoaidprogrammingwhenmachiningcomplexcontours.連續(xù)路徑機(jī)器都高于點(diǎn)對(duì)點(diǎn)系統(tǒng),一般要求計(jì)算機(jī)援助方案在加工復(fù)雜輪廓。N/Cincreaseflexibility.Engineeringchangesinproductionpartsarelesscostlyandmorerapid,sincechangeswithN/Carequicklyaccomplishedbychangingataperatherthanbuildingnewjigsandfixtures.N/C增加靈活性。工程生產(chǎn)部分變化較少價(jià)格昂貴，而且由于N/C的變化快速通過(guò)更改更快磁帶而不建立新的夾具和固定裝置。第二十一章：機(jī)器人1.Notethatthisdefinitioncontainsthewordsreprogrammableandmultifunction.Itisthesetwocharacteristicsthatseparatethetrueindustrialrobotfromthevarioussingle-purposemachinesusedinmodernmanufacturingfirms.注意本定義包含了可重編程和多功能的特點(diǎn)。就是這兩點(diǎn)把現(xiàn)代制造企業(yè)中的真正