機(jī)械工程專業(yè)英語(yǔ)唐一平翻譯

1、Unit11.2FerrousMetalsAlloysByvirtueoftheirwiderangeofmechanicalphysicalchemicalpropertiesferrousmetalsalloysareamongthemostusefulofallmetals.Ferrousmetalsalloyscontainironastheirbasemetal:thegeneralcategiesarecastironsca

2、rbonalloysteelsstainlesssteelstooldiesteels.1.2黑色金屬及其合金：由于它們的一系列廣泛的機(jī)械物理和化學(xué)的特征，黑色金屬及其合金是所有金屬中最有用的鐵是黑色金屬及其合金中的基本元素主要種類有鑄鐵，碳鋼，合金鋼，不銹鋼，工具鋼和磨具鋼Thetermcastironreferstoafamilyofferrousalloyscomposedofironcarbon(rangingfrom2.11%

3、toabout4.5%)silicon(uptoabout3.5%).Castironsareusuallyclassifiedasfollows:1.Graycastirongrayiron2.Ductilecastironnodularcastironsphericalgraphitecastiron3.Whitecastiron4.Malleableironpactedgraphiteiron。（），它包含鐵碳（2.5%—4.5%

4、）和硅（3.5%）鑄鐵的分類如下1.灰鑄鐵2.球墨鑄鐵3.白口鑄鐵4.可鍛鑄鐵5.如墨鑄鐵TheequilibriumphasediagramrelevanttocastironsisshowninFig.1.1inwhichtherightboundaryis100%carbonthatispuregraphite.Theeutectictemperatureis1154hC(2109hF)socastironsarecomplete

5、lyliquidattemperatureslowerthanthoserequiredfliquidsteels.Consequentlyironwithhighcarboncontentcanbecastatlowertemperaturesthancansteels.有關(guān)鑄鐵的平衡相圖如圖1.1所示其右邊界是100%的碳那是純石墨，其共晶溫度是1154℃因此鑄鐵可以在比那些熔化鋼更低的溫度下完全液化所以含碳量較高的鑄鐵的澆注溫度比

6、鋼低。Carbonsteelsaregenerallyclassifiedbytheirproption(byweight)ofcarboncontent.1.Lowcarbonsteelalsocalledmildsteelhaslessthan1.30%carbon.Itisgenerallyusedfcommonindustrialproductssuchasboltsnutssheetplatetubesfmachinecomp

7、onentsthatdonotrequirehighstrength.3.碳鋼：碳銅大體上是按碳含量的臂力來(lái)分類的1）低碳鋼又叫做軟鋼其碳含量小于0.30%它用于普遍的工業(yè)產(chǎn)品，例如螺栓，螺母。鋼板，港片鋼管和那些強(qiáng)度要求不高的機(jī)器零件Unit55.1IntroductionConventionalmachiningisthegroupofmachiningoperationsthatusesinglemultipointtoolsto

8、removematerialinthefmofchips.Metalcuttinginvolvesremovingmetalthroughmachiningoperations.Machiningtraditionallytakesplaceonlathesdrillpressesmillingmachineswiththeuseofvariouscuttingtools.Mostmachininghasverylowsetupcost

9、comparedwithfmingmoldingcastingprocesses.Howevermachiningismuchmeexpensivefhighvolumes.Machiningisnecessarywheretighttolerancesondimensionsfinishesarewithabsoluteaccuracy.Actualsurfacesoftheproducedpartstherefedifferfrom

10、idealsurfacesprescribedindrawings.Deviationsofactualsurfacesaredividedintofourgroupstoenableassessmentpreioncheckingofthepermittedinaccuracyduringproduction:1:Dimensionaldeviations2:Shapedeviations3:Positiondeviations4:S

11、urfaceroughnessdeviations.一張工程圖應(yīng)有恰當(dāng)?shù)某叽鐦?biāo)注，來(lái)把設(shè)計(jì)師的想法傳遞給用戶，加工出的零件尺寸應(yīng)與圖紙上所標(biāo)注的零件尺寸完全一致并匹配，但是加工零件的尺寸不可能是精確的尺寸，大多數(shù)的尺寸都有一個(gè)加工范圍，這是可接受的規(guī)定尺寸變化極限的一種方法，以至于可以接受并使用這一加工零件，各個(gè)零件的尺寸精度，形狀精度，互換位置精度必須保持在一個(gè)精度范圍以內(nèi)，以便正確可靠的實(shí)現(xiàn)他們的功能，常規(guī)的加工過(guò)程不允許對(duì)具有絕對(duì)