第5章-Kinds-of-Steel知识讲解

第5章-Kinds-of-Steel

(2) Mediumcarbonsteelcontainingfrom0.15to0.60percentcarbon.

(3) Highcarbonsteelcontainingfrom0.6to1.50percentcarbon;thissteelissometimescalled“toolsteel”.

2．Alloysteels

(1) Specialalloysteel,suchasnickel,chromiumsteel;

(2) High-speedsteelalsoknownasself-hardeningsteel.Carbonsteelsarethemostcommonsteelsusedinindustry.Thepropertiesofthesesteelsdependonlyonthepercentageofcarbontheycontain.Lowcarbonsteelsareverysoftandcanbeusedforboltsandformachinepartsthatdonotneedstrength.

Mediumcarbonsteelsareabettergradeandstrongerthanlowcarbonsteels.Itisalsomoredifficulttocutthanlowcarbonsteels.

Highcarbonsteelsmaybehardenedbyheatingittoacertaintemperatureandthenquicklycoolinginwater.Themorecarbonthesteelscontainsandthequickerthecoolingis,theharderitbecomes.Becauseofitshighstrengthandhardnessthisgradeofsteelmaybeusedfortoolsandworkingpartsofmachines.

Butforsomespecialuses,forexample,forgears,bearings,springs,shaftsandwire,carbonsteelscannotbealwaysusedbecausetheyhavenopropertiesneededfortheseparts.

Somespecialalloysteelsshouldbeusedforsuchpartsbecausethealloyingelementsmakethemtougher,stronger,orharderthancarbonsteels.Somealloyingelementscausesteeltoresistcorrosion,andsuchsteelsarecalledstainlesssteels.Stainlesssteelscontainahighpercentageofchromium.Chromiumalsomakessteelharder.Nickelisusedinsteeltoincreasestrengthandtoughness.Somealloyingelements(suchaschromiumandtungsten)makethegrainofsteelfiner,thusincreasingthehardnessandstrengthofsteel,becausethefinerthegrainis,thestrongerthesteelbecomes.

Heat-resistantsteelismadebyaddingsometungstenandmolybdenum,whilemanganeseincreasesthewearresistanceofsteel.Vanadiumsteelsresistcorrosionandcanstandshocksandvibration.

Toolsmadeofhigh-speedsteelcontainingtungsten,chromium,vanadium,andcarbon,maydotheworkatmuchhigherspeedsthancarbontoolsteels.LEARNTOSPEAKMr.Yang: Morning!Mr.Smith: Morning!Mr.Yang: Doyouknowaboutthekindsofsteels?Mr.Smith: Yes,therearetwogeneralkindsofsteels:carbonsteelandalloysteel.Mr.Yang: Couldyoudescribeitindetail?Mr.Smith: Ok.Carbonsteelcontainsonlyironandcarbon,whilealloysteelcontainssomeother“alloyingelements”suchasnickel,chromium,etc.Mr.Yang: Whatcanthecarbonsteelbeusedfor?Mr.Smith: Thecarbonsteelcontainslow,mediumandhighcarbonsteel,andcanbeusedforbolts,toolsandworkingpartsofmachines.Mr.Yang: Then,whatcanthealloysteelbeusedfor?Mr.Smith: Alloysteelcanbeusedforgears,bearings,springsandwires,etc.Becausethealloyingelementsmakethemtougher,stronger,orharderthancarbonsteel.Mr.Yang: Howaboutthetoolswhichmadeofhighspeedsteel?Mr.Smith: Thetoolsmadeofhigh-speedsteelofalloysteelcontainingtungsten,chromium,vanadiumandcarbon,maydotheworkatmuchhigherspeedsthancarbontoolsteels.NEWWORDSANDPHRASESnickel ['nɪkl]n.镍chromium [ˈkrəʊmiəm]n.铬Manganese[mængˈni:z] n.锰molybdenum [məˈlɪbdənəm]n.钼tungsten ['tʌŋstən]n.钨vanadium [vəˈneɪdiəm]n.钒medium ['mi:dɪəm]n.介质a.中间的

harden ['hɑ:dn] v.淬火bolt [bəʊlt] n.螺栓，螺钉v.用螺栓固定gear [ɡɪə] n.齿轮bearing n.轴承shaft [ʃɑ:ft] n.轴corrosion [kə'rəʊʒn] n.腐蚀stainless ['steɪnlɪs] n.不锈钢grain ['greɪn] n.晶粒toolsteel 工具钢self-hardeningsteel 自硬钢heat-resistant 耐热的heat-resistantsteel 耐热钢high-speed 高速的NOTES1．high-speedsteelalsoknownasself-hardeningsteel.

高速钢，也称为自硬钢。

“alsoknownasself-hardeningsteel”为分词短语作定语，修饰“high-speedsteel”。高速钢是一种含有钨、铬、钒等合金元素的高合金工具钢，它可以在空气中自行淬硬，因而又称“self-hardeningsteel”，故又称为风钢。2．Themorecarbonthesteelcontainsandthequickerthecoolingis,theharderitbecomes.

钢的含碳量越高，冷却速度越快，钢就变得越硬。

“the+比较级……(从句)+the+比较级……(主句)”结构表示“越……越……”之意。

本句中的比较状语从句为“Themorecarbonthesteelcontainandthequickerthecoolingis”。主句为“theharderitbecomes”。句中第一个“the”和第二个“the”均为副词，分别引出两个并列的比较状语从句。在这种情况下，第一个“the”相当于“bysomuch”，第二个“the”相当于“bythatmuch”。3．becausethealloyingelementsmakethemtoughers,strongerorharderthancarbonsteels.Somealloyingelementscausesteeltoresistcorrosion,andsuchsteelarecalledstainlesssteels.

因为合金元素能提高钢的韧性、强度和硬度(在碳钢的基础上)。有些合金元素能提高钢的耐蚀性，这种钢称做不锈钢。

句中的“make”和“cause”均为及物动词，它们的宾语分别为“them”和“steel”。作为宾语“them”的补足语是形容词比较级“tougher,stronger,harder”等，现时作为宾语“steel”的补足语是不定式短语“toresistcorrosion”。“stainlesssteels”是主语“suchsteel”的补足语。4．Toolsmadeofhigh-speedcontainingtungsten,chromium,vanadiumandcarbon,maydotheworkatmuchhigherspeedsthancarbontoolsteels.

用含有钨、铬、钒、碳的高速钢制成的刀具能以比碳素工具钢高得多的速度进行切削加工。

“madeofhigh-speedsteel”作为分词短语，修饰“Tools”，而“containingtungsten,chromium,chromium,vanadiumandcarbon”是另一分词短语作后置短语，修饰“high-speedsteel”。EXERCISES1．DiscussthefollowingquestionsinEnglish:(1)  Whatmethodsareavailableforimprovingthehardnessofhighcarbonsteel?(2)  Whatarethemachinepartsmadeof,thatdonotneedstrength?(3)  Howdothealloyingelementssuchaschromiumandtungstenincreasethehardnessandstrengthofsteel?2．UseEnglishforreplacingChineseoruseChineseforreplacingEnglish.(1)碳钢和合金钢

(2)材料的性能

(3)高速钢

(4) heat-resistantsteel(5) self-hardeningsteel(6) nickelsteel3．Placea“T”aftersentencesthataretrueandan“F”afterthosethatarefalse.(1) Alloyshavingmorethan0.6%carbonarecalledhighcarbonsteels.()(2) Alloyscontaining0.15%(orless)carbonarecalledlowcarbonsteels.()(3) Highspeedsteelissometimescalledself-hardeningsteel.()(4) Thepropertiesofcarbonsteelsdependnotonlyonthepercentageofcarbontheycontain,butalsoonthealloyingelements.()(5) Steelscontainmorecarbonthancastirons.()(6) Lowcarbonsteelisharderthanhighcarbonsteel.()(7) Toolsmadeofhigh-speedsteeldotheworkatmuchlowerspeedsthancarbonsteels.()(8) Stainlesssteelscontainsomealloyingelementswhichcausesteelstoresistcorrosion.()Strength.StrengthorMechanicalStrengthofamaterialmaybedefinedastheabilityofthematerialtosustainloadswithoutunduedistortionorfailure.Materialshouldhaveadequatestrengthwhensubjectedtotension,compression,shear,bendingortorsionaspertheintendeduse.Stiffness.Stiffnessistheabilityofamaterialorshapetoresistelasticdeflection.Foridenticalshapes,thestiffnessisproportionaltothemodulusofelasticity.Ductility.Ductilityreferstothecapacityofamaterialtoundergodeformationundertensionwithoutruptureasinawiredrawingoperation.PROFESSIONALWORDSANDPHRASESessential[I5senF(E)l] adj.主要的，根本的n.本质，基础sound [saJnd] adj.健全的，坚固的conduct [kEn5dQkt] vt.实施，进行experimental [Ik5sperIment(E)l] adj.试验(用)的specimen [5spesImEn] n.样品，试样strength [streNW] n.强度tension [5tenF(E)n] n.张(拉)力，拉伸compression [kEm5preF(E)n] n.压力，压缩shear [FIE(r)] n.剪(切)stiff [stIf] adj.刚(性)的stiffness [5stIfnIs] n.刚度，强度impact [5ImpAkt] n.冲击ductility [dQk`tIlEtI] n.延(展)性，韧性hardness [5hB:dnIs] n.硬度toughness [tQfnIs] n.韧性，韧度load [lEJd] n.负载，载荷sustain [sE5steIn] vt.支持，维持undue [Qn5dju:;(?@)Qn5du:] adj.过度的distortion [dIs`tR:FEn] n.变形，歪曲failure [5feIljE(r)]