洛阳理工专业英语课件

2.1.2CarbonandAlloySteel

◆CarbonSteel碳钢Aplain

普通的，朴素的carbonsteelisoneinwhichcarbonistheonlyalloying

合金化element.Theamountofcarboninthesteelcontrolsitshardness,strength,andductility.Thehigherthecarboncontent,theharderthesteel.Carbonsteelsareclassifiedaccordingtothepercentageofcarbontheycontain.Theyarereferredto

涉及；谈到

aslow,medium,high,andveryhigh-carbonsteels.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII1

Low-carbonSteels低碳钢=mildsteelSteelswithcarbonrangeof0.05to0.30percentarecalledlow-carbonsteels.Steelsinthisclass

类别aretough

韧性的，坚韧的,ductile

易延展的,andeasilymachined用机器加工,formed,andwelded.Mostofthemdonotrespondto

对…做出响应anyheattreatingprocessexceptcase

箱，盒

hardening表面淬火.

Medium-carbonSteels中碳钢Thesesteelshaveacarbonrangefrom0.30to0.45percent.Theyarestrongandhardbutcannotbeworkedorweldedaseasilyaslow-carbonsteels.Becauseoftheirhighercarboncontent,theycanbeheattreated热处理.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel2Successfulweldingofthesesteelsoftenrequiresspecialelectrodes

焊条；电极,buteventhengreatercaremustbetakentopreventformationofcracksaroundtheweldarea.

HighandVery-high-carbonSteels高碳钢和超高碳钢Steelswithacarbonrangeof0.45to0.75percentareclassifiedashigh-carbonandthosewith0.75to1.7percentcarbonasvery-high-carbonsteels.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel3Bothofthesesteelsrespondwellto

对…产生回应heattreatment.Asarule

一般说来

,steelsupto

直到0.65percentcarboncanbeweldedwithspecialelectrodes特殊焊条,althoughpreheating

预热（pre-welding焊前,post-welding焊后)andstressrelievingtechniques(工艺technology;craft;industrialart;workmanship;process;technique)

mustoftenbeusedaftertheweldingiscompleted.Usuallyitisnotpracticaltoweldsteelsinthevery-high-carbonrange.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel4Carbonistheprincipal

主要的，首要的；中小学校长elementcontrollingthestructureandpropertiesthatmightbeexpectedfromanycarbonsteel.Theinfluencethatcarbonhasinstrengtheningandhardeningsteelisdependentupontheamountofcarbonpresentanduponitsmicrostructure.Slowlycooledcarbonsteelshavearelativelysoftironpearlitic

珠光体的

（pearlite珠光体）microstructure微观组织，显微组织;ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel5whereas

反之rapidlyquenchedcarbonsteelshaveastrong,hard,brittle,martensitic

马氏体的

(martensite马氏体）microstructure.Incarbonsteelatnormal正常的（abnormal

不正常的）roomtemperature,theatomsarearrangedinabody-centeredlattice

晶格，空间点阵.Thisisknownas被称作，以…著称alphairon.Eachgrain

晶粒=crystalgrain

ofthestructureismadeupoflayersofpureiron(ferrite)andacombinationofironandcarbon.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel6Thecompound化合物ofironandcarbon,orironcarbide

碳化物,iscalledcementite

渗碳体=Cm,Fe3C.Thecementiteisveryhardandhaspracticallynoductility.Inasteelwith0.8percentcarbon,thegrainsarepearlitic,meaningthatallthecarboniscombinedwithirontoformironcarbide.Thisisknownasaeutectoid共析的mixtureofcarbonandiron.SeeFigure2.1.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel7Ifthereislessthan0.8percentcarbon,themixtureofpearlite

珠光体andferrite

铁素体

referredtoas

把…称作=beknownas

hypoeutectoid

亚共析.AnexaminationofsuchamixturewouldshowgrainsofpureironandgrainsofpearliteasshowninFigure2.2.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel8Whenthemetalcontainsmorethan(反义词：lessthan)0.8percentcarbon,themixtureconsistsofpearliteandironcarbideandiscalledhypereutectoid

过共析.NoticeinFigure2.3howthegrains(crystalgrain)ofpearlitearesurrounded围绕byironcarbide

(Fe3C).Ingeneral一般而言,thegreatestpercentageofsteelusedisofthehypoeutectoid

亚共析type,thatwhichhaslessthan

（反义词：morethan）0.8percentcarbon.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel9ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel10◆AlloySteel合金钢Analloysteelisasteeltowhichoneormoreofsuchelementsasnickel镍,chromium铬,manganese锰,molybdenum钼,titanium钛,cobalt[kəu‘bɔ:lt]

钴,tungsten钨,orvanadium钒havebeenadded.Theadditionoftheseelementsgivessteelgreatertoughness,strength,resistancetowear耐磨性,andresistancetocorrosion

耐腐蚀性.Alloysteelsarecalledbythepredominating占统治地位的elementwhichhasbeenadded.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel11

Most

大部分的ofthemcanbewelded,providedspecialelectrodes电焊条areused.Thecommonelementsaddedtosteelandtheireffects影响areexplainedasthefollowing.

ManganeseTheadditionofmanganesetosteelproducesafinegrainstructurewhichhasgreatertoughness

韧性andductility

延展性.Manganesealwayspresentsinasteeltosomeextent

达到某种程度becauseitisusedasadeoxidiser

脱氧剂.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel12

siliconAlwayspresenttosomeextent,becauseitisusedwithmanganeseasadeoxidiser.

ChromiumWhenquantitiesof

大量的chromiumareaddedtosteeltheresultingproductisametalhavingextreme

极端的hardnessandresistancetowearwithoutmakingitbrittle.Chromiumalsotendstorefine改善；提炼thegrainstructureofsteel,therebyincreasingitstoughness.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel13Itisusedeitheraloneincarbonsteelorincombination

结合withotherelementssuchasnickel,vanadium,molybdenum,ortungsten.

NickelTheadditionofnickelincreasestheductilityofsteelwhileallowingittomaintainitsstrength.Whenlargequantitiesofnickelareadded(25to35percent),thesteelsnotonlybecometoughbutalsodevelophighresistancetocorrosionandshock

冲击.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel14

TungstenTungstenisusedmostlyinsteelsdesignedformetalcuttingtools.Tungstensteelsaretough,hard,andveryresistanttowear.

MolybdenumMolybdenumproducesthegreatesthardeningeffectofanyelementexceptcarbonandatthesametimeitreducestheenlargement增大ofthegrainstructure.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel15Theresultisastrong,toughsteel.Althoughmolybdenumisusedaloneinsomealloys,oftenitissupplemented补充byotherelements,particularlynickelorchromiumorboth.

VanadiumVanadiumisastrongcarbideformingelement.Additionofthiselementtosteelpromotesfinegrainstructurewhenthesteelisheatedaboveitscritical临界的；爱挑剔的，吹毛求疵的rangeforheattreatment.ENGLISHINMATERIALSSCIENCEANDENGINEERINGII2.1.2CarbonandAlloySteel16Italsoimparts传递toughnessand