Aqtvlxl机械制造及自动化毕业设计外语文献翻译

1、生命中，不不断地有人人离开或进进入。于是是，看见的的，看不见见的；记住住的，遗忘忘了。生命命中，不断断地有得到到和失落。于是，看看不见的，看看见了；遗遗忘的，记记住了。然然而，看不不见的，是是不是就等等于不存在在？记住的的，是不是是永远不会会消失？ 攀枝花学院院本科毕业业设计（论论文）外文译文院 （系）： 机电工工程学院 专 业： 机械械设计制造造及其自动动化 姓 名： 王 中中 蔚 学 号： ZJJD020043 指导教师评评语： 签签名： 年 月月 日外语文献翻翻译摘自: 制造工工程与技术术（机加工工）（英英文版） MManuffactuuringg Enggineeeringg andd

2、 TecchnollogyMachhininng 机械械工业出版版社 22004年年3月第1版 美 s. 卡卡尔帕基安安(Serrope kalppakjiian) s.rr 施密德德(Steeven R.Scchmidd) 著原文：20.9 MACHHINABBILITTYThe mmachiinabiilityy of a maateriial uusuallly ddefinned iin teerms of ffour facttors:Surfaace ffinissh annd inntegrrity of tthe mmachiined partt;Tool lifee obtt

3、aineed;Forcee andd powwer rrequiiremeents;Chip conttrol. Thus, goood maachinnabillity goodd surrfacee finnish and inteegritty, llong tooll liffe, aand llow fforcee Andd powwer rrequiiremeents. As for chipp conntroll, loong aand tthin (strringyy) cuured chipps, iif noot brrokenn up, cann sevverelly i

4、nnterffere withh thee cutttingg opeeratiion bby beecomiing eentanngledd in the cuttting zonee.Becauuse oof thhe coompleex naaturee of cuttting operratioons, it iis diifficcult to eestabblishh rellatioonshiips tthat quanntitaativeely ddefinne thhe maachinnabillity of aa matteriaal. IIn maanufaacturri

5、ng plannts, tooll liffe annd suurfacce rooughnness are geneerallly coonsidderedd to be tthe mmost impoortannt faactorrs inn macchinaabiliity. Althhoughh nott useed muuch aany mmore, appproxiimatee macchinaabiliity rratinngs aare aavaillablee in the exammple beloow.20.9.1 Maachinnabillity Of SSteells

6、Becauuse ssteells arre ammong the mostt impportaant eenginneeriing mmaterrialss (ass notted iin Chhapteer 5), thheir machhinabbilitty haas beeen sstudiied eextennsiveely. The machhinabbilitty off steeels has beenn maiinly imprrovedd by addiing llead and sulffur tto obbtainn so-callled ffree-machhini

7、nng stteelss.Resullfuriized and Rephhosphhorizzed ssteells. Sulffur iin stteelss forrms mmangaanesee sullfidee incclusiions (seccond-phasse paarticcles), whhich act as sstresss raaiserrs inn thee priimaryy sheear zzone. As a reesultt, thhe chhips prodducedd breeak uup eaasilyy andd aree smaall; this

8、s impprovees maachinnabillity. Thee sizze, sshapee, diistriibutiion, and conccentrratioon off theese iincluusionns siignifficanntly inflluencce maachinnabillity. Eleementts suuch aas teellurrium and seleeniumm, whhich are bothh cheemicaally simiilar to ssulfuur, aact aas innclussion modiifierrs inn

9、ressulfuurizeed stteelss.Phospphoruus inn steeels has two majoor efffectts. IIt sttrenggthenns thhe feerritte, ccausiing iincreeasedd harrdnesss. HHardeer stteelss ressult in bbetteer chhip fformaationn andd surrfacee finnish. Notte thhat ssoft steeels ccan bbe diifficcult to mmachiine, withh buiilt

10、-uup eddge fformaationn andd pooor suurfacce fiinishh. Thhe seecondd efffect is tthat incrreaseed haardneess ccausees thhe foormattion of sshortt chiips iinsteead oof coontinnuouss strringyy onees, tthereeby iimproovingg macchinaabiliity.Leadeed Stteelss. A highh perrcenttage of llead in ssteells so

11、olidiifiess at the tip of mmangaanesee sullfidee incclusiions. In non-resuulfurrizedd graades of ssteell, leead ttakess thee forrm off dissperssed ffine partticlees. LLead is iinsollublee in ironn, coopperr, annd alluminnum aand ttheirr allloys. Beccausee of its low sheaar sttrenggth, therreforre, l

12、lead actss as a soolid lubrricannt (SSectiion 332.111) annd iss smeearedd oveer thhe toool-cchip inteerfacce duuringg cutttingg. Thhis bbehavvior has beenn verrifieed byy thee preesencce off higgh cooncenntrattionss of leadd on the tooll-sidde faace oof chhips whenn macchiniing lleadeed stteelss.Whe

13、n the tempperatture is ssuffiicienntly highh-forr insstancce, aat hiigh ccuttiing sspeedds annd feeeds (Secctionn 20.6)tthe llead meltts diirecttly iin frront of tthe ttool, actting as aa liqquid lubrricannt. IIn addditiion tto thhis eeffecct, llead loweers tthe sshearr strress in tthe pprimaary ssh

14、earr zonne, rreduccing cuttting forcces aand ppowerr connsumpptionn. Leead ccan bbe ussed iin evvery gradde off steeel, suchh as 10 xxx, 111xx, 12xxx, 411xx, etc. Leaaded steeels aare iidenttifieed byy thee lettter L beetweeen thhe seecondd andd thiird nnumerrals (forr exaamplee, 100L45). (NNote tha

15、tt in staiinlesss stteelss, siimilaar usse off thee lettter L meeans “loww carrbon,” a condditioon thhat iimprooves theiir coorrossion resiistannce.)Howevver, becaause leadd is a weell-kknownn toxxin aand aa polllutaant, therre arre seeriouus ennviroonmenntal conccernss aboout iits uuse iin stteelss

16、 (esstimaated at 44500 tonss of leadd connsumpptionn eveery yyear in tthe pproduuctioon off steeels). Coonseqquenttly, therre iss a ccontiinuinng trrend towaard eelimiinatiing tthe uuse oof leead iin stteelss (leead-ffree steeels). Bissmuthh andd tinn aree noww beiing iinvesstigaated as ppossiible s

17、ubsstituutes for leadd in steeels.Calciium-DDeoxiidizeed Stteelss. Ann impportaant ddevellopmeent iis caalciuum-deeoxiddizedd steeels, in whicch oxxide flakkes oof caalciuum siilicaates (CaSSo) aare fformeed. TThesee flaakes, in turnn, reeducee thee strrengtth off thee seccondaary sshearr zonne, dde

18、creeasinng toool-cchip inteerfacce annd weear. Tempperatture is ccorreesponndinggly rreducced. Conssequeentlyy, thhese steeels pproduuce lless cratter wwear, esppeciaally at hhigh cuttting speeeds.Stainnlesss Steeels. Aussteniitic (3000 serries) steeels are geneerallly diifficcult to mmachiine. Chat

19、tter can be ss prooblemm, neecesssitatting machhine toolls wiith hhigh stifffnesss. HHowevver, ferrriticc staainleess ssteells (aalso 300 seriies) havee goood maachinnabillity. Marrtenssiticc (4000 seeriess) stteelss aree abrrasivve, ttend to fform a buuilt-up eedge, andd reqquiree toool maateriials

20、 withh higgh hoot haardneess aand ccrateer-weear rresisstancce. PPreciipitaationn-harrdeniing sstainnlesss steeels are stroong aand aabrassive, reqquiriing hhard and abraasionn-ressistaant ttool mateerialls.The EEffeccts oof Otther Elemmentss in Steeels oon Maachinnabillity. Thee preesencce off aluu

21、minuum annd siilicoon inn steeels is aalwayys haarmfuul beecausse thhese elemmentss commbinee witth oxxygenn to formm aluuminuum oxxide and siliicatees, wwhichh aree harrd annd abbrasiive. Thesse coompouunds incrreasee toool weear aand rreducce maachinnabillity. It is eessenntiall to prodduce and us

22、e cleaan stteelss.Carboon annd maangannese havee varriouss efffectss on the machhinabbilitty off steeels, deppendiing oon thheir compposittion. Plaain llow-ccarboon stteelss (leess tthan 0.155% C) cann prooducee pooor suurfacce fiinishh by formming a buuilt-up eedge. Casst stteelss aree morre abbras

23、iive, althhoughh theeir mmachiinabiilityy is simiilar to tthat of wwrougght ssteells. TTool and die steeels aare vvery diffficullt too macchinee andd usuuallyy reqquiree annnealiing ppriorr to machhininng. MMachiinabiilityy of mostt steeels is iimprooved by ccold workking, whiich hhardeens tthe mmat

24、errial and reduuces the tenddencyy forr buiilt-uup eddge fformaationn.Otherr allloyinng ellemennts, suchh as nickkel, chroomiumm, moolybddenumm, annd vaanadiium, whicch immprovve thhe prroperrtiess of steeels, geneerallly reeducee macchinaabiliity. The effeect oof booron is nnegliigiblle. GGaseoous

25、eelemeents suchh as hydrrogenn andd nittrogeen caan haave ppartiiculaarly detrrimenntal effeects on tthe ppropeertiees off steeel. Oxyggen hhas bbeen showwn too havve a stroong eeffecct onn thee asppect ratiio off thee mannganeese ssulfiide iincluusionns; tthe hhigheer thhe oxxygenn conntentt, thhe

26、loower the aspeect rratioo andd thee higgher the machhinabbilitty.In seelectting variious elemmentss to imprrove machhinabbilitty, wwe shhouldd connsideer thhe poossibble ddetriimenttal eeffeccts oof thhese elemmentss on the proppertiies aand sstrenngth of tthe mmachiined partt in servvice. At elevv

27、atedd temmperaaturees, ffor eexampple, leadd cauuses embrrittllemennt off steeels (liqquid-metaal emmbritttlemment, hott shoortneess; see Secttion 1.4.3), althhoughh at roomm temmperaaturee it has no eeffecct onn mecchaniical proppertiies.Sulfuur caan seevereely rreducce thhe hoot woorkabbilitty off

28、 steeels, beccausee of the formmatioon off iroon suulfidde, uunlesss suufficcientt mannganeese iis prresennt too preeventt succh foormattion. At roomm temmperaaturee, thhe meechannicall proopertties of rresullfuriized steeels ddepennd onn thee oriientaationn of the defoormedd mannganeese ssulfiide i

29、incluusionns (aanisootroppy). Rephhosphhorizzed ssteells arre siignifficanntly lesss ducctilee, annd arre prroducced ssolelly too impprovee macchinaabiliity.20.9.2 Maachinnabillity of VVarioous OOtherr Mettals Alumiinum is ggenerrallyy verry eaasy tto maachinne, aalthoough the softter ggradees teend

30、 tto foorm aa buiilt-uup eddge, resuultinng inn pooor suurfacce fiinishh. Hiigh ccuttiing sspeedds, hhigh rakee anggles, andd higgh reelieff anggles are recoommennded. Wrooughtt aluuminuum allloyss witth hiigh ssiliccon cconteent aand ccast alumminumm allloys may be aabrassive; theey reequirre haard

31、err toool maateriials. Dimmensiionall tollerannce ccontrrol mmay bbe a probblem in mmachiiningg aluuminuum, ssincee it has a hiigh tthermmal ccoeffficieent oof exxpanssion and a reelatiivelyy loww elaasticc modduluss.Beryllliumm is simiilar to ccast ironns. BBecauuse iit iss morre abbrasiive aand tt

32、oxicc, thhoughh, itt reqquirees maachinning in aa conntrollled enviironmment.Cast grayy iroons aare ggenerrallyy macchinaable but are. Freee caarbiddes iin caastinngs rreducce thheir machhinabbilitty annd caause tooll chiippinng orr fraacturre, nnecesssitaatingg toools wwith highh touughneess. Noduu

33、lar and mallleablle irrons are machhinabble wwith hardd toool maateriials.Coballt-baased allooys aare aabrassive and highhly wwork-harddeninng. TThey requuire sharrp, aabrassion-resiistannt toool mmaterrialss andd loww feeeds aand sspeedds.Wrougght ccoppeer caan bee diffficuult tto maachinne beecaus

34、se off buiilt-uup eddge fformaationn, allthouugh ccast coppper aalloyys arre eaasy tto maachinne. BBrassses aare eeasy to mmachiine, espeeciallly wwith the addiitionn pf leadd (leeadedd freee-maachinning brasss). Bronnzes are moree diffficuult tto maachinne thhan bbrasss.Magneesiumm is veryy eassy t

35、oo macchinee, wiith ggood surfface finiish aand pproloongedd toool liife. Howeever caree shoould be eexerccisedd beccausee of its highh ratte off oxiidatiion aand tthe ddangeer off firre (tthe eelemeent iis pyyrophhoricc).Molybbdenuum iss ducctilee andd worrk-haardenning, so it ccan pproduuce ppoor

36、surfface finiish. Sharrp toools are neceessarry.Nickeel-baased allooys aare wwork-harddeninng, aabrassive, andd strrong at hhigh tempperatturess. Thheir machhinabbilitty iss simmilarr to thatt of staiinlesss stteelss.Tantaalum is vvery workk-harrdeniing, ducttile, andd sofft. IIt prroducces aa pooor

37、 suurfacce fiinishh; toool wwear is hhigh.Titannium and its allooys hhave poorr theermall connducttivitty (iindeeed, tthe llowesst off alll mettals), caausinng siignifficannt teemperraturre riise aand bbuiltt-up edgee; thhey ccan bbe diifficcult to mmachiine.Tungssten is bbritttle, stroong, and very

38、y abrrasivve, sso itts maachinnabillity is llow, althhoughh it greaatly imprrovess at elevvatedd temmperaaturees.Zircooniumm hass goood maachinnabillity. It requuiress a ccoolaant-ttype cuttting fluiid, hhowevver, becaause of tthe eexploosionn andd firre.20.9.3 Maachinnabillity of VVarioous MMaterri

39、alssGraphhite is aabrassive; it requuiress harrd, aabrassion-resiistannt, ssharpp toools.Thermmoplaasticcs geeneraally havee loww theermall connducttivitty, llow eelasttic mmodullus, and low softteninng teemperraturre. CConseequenntly, macchiniing tthem requuiress toools wwith posiitivee rakke anngl

40、ess (too redduce cuttting forcces), larrge rrelieef anngless, smmall deptths oof cuut annd feeed, relaativeely hhigh speeeds, and propeer suupporrt off thee worrkpieece. Toolls shhouldd be sharrp.Exterrnal coolling of tthe ccuttiing zzone may be nnecesssaryy to keepp thee chiips ffrom becoomingg “gu

41、ummy” andd stiickinng too thee toools. Coolling can usuaally be aachieeved withh a jjet oof aiir, vvaporr misst, oor waater-soluuble oilss. Reesiduual sstressses may deveelop duriing mmachiiningg. Too rellievee theese sstressses, macchineed paarts can be aanneaaled for a peeriodd of timee at tempper

42、atturess ranngingg froom tto (to), and thenn coooled slowwly aand uunifoormlyy to roomm temmperaaturee.Thermmosetttingg plaasticcs arre brrittlle annd seensittive to tthermmal ggradiientss durring cuttting. Theeir mmachiinabiilityy is geneerallly siimilaar too thaat off theermopplasttics.Becauuse oo

43、f thhe fiiberss preesentt, reeinfoorcedd plaasticcs arre veery aabrassive and are diffficullt too macchinee. Fiiber tearring, pulllingg, annd eddge ddelamminattion are signnificcant probblemss; thhey ccan llead to sseverre reeducttion in tthe lload-carrryingg cappacitty off thee commponeent. Furtthe

44、rmmore, macchiniing oof thhese mateerialls reequirres ccarefful rremovval oof maachinning debrris tto avvoid conttact withh andd inhhalinng off thee fibbers.The mmachiinabiilityy of ceraamicss hass impproveed stteadiily wwith the deveelopmment of nnanoccerammics (Secctionn 8.22.5) and withh thee sel

45、lectiion oof appproppriatte prrocesssingg parrametters, succh ass ducctilee-reggime cuttting (Secctionn 22.4.2).Metall-mattrix and ceraamic-matrrix ccompoositees caan bee diffficuult tto maachinne, ddepenndingg on the proppertiies oof thhe inndiviiduall commponeents, i.ee., rreinfforciing oor whhisk

46、eers, as wwell as tthe mmatriix maateriial.20.9.4 Thhermaally Assiistedd MacchiniingMetalls annd allloyss thaat arre diifficcult to mmachiine aat rooom ttempeeratuure ccan bbe maachinned mmore easiily aat ellevatted ttempeeratuures. In therrmallly asssistted mmachiiningg (hoot maachinning), thhe soo

47、urcee of heatta ttorchh, innducttion coill, hiigh-eenerggy beeam (suchh as laseer orr eleectroon beeam), or plassma aarciis foorcess, (bb) inncreaased tooll liffe, (c) uuse oof innexpeensivve cuuttinng-toool mmaterrialss, (dd) hiigherr matteriaal-reemovaal raates, andd (e) redducedd tenndenccy foor

48、viibrattion and chattter.It maay bee diffficuult tto heeat aand mmainttain a unniforrm teemperraturre diistriibutiion wwithiin thhe woorkpiiece. Alsso, tthe oorigiinal micrrostrructuure oof thhe woorkpiiece may be aadverrselyy afffecteed byy eleevateed teemperraturres. Mostt appplicaationns off hott

49、 macchiniing aare iin thhe tuurninng off higgh-sttrenggth mmetalls annd allloyss, allthouugh eexperrimennts aare iin prrogreess tto maachinne ceeramiics ssuch as ssiliccon nnitriide. SUMMAARYMachiinabiilityy is usuaally defiined in ttermss of surfface finiish, tooll liffe, fforcee andd powwer rrequi

50、iremeents, andd chiip coontrool. MMachiinabiilityy of mateerialls deependds noot onnly oon thheir intrrinsiic prroperrtiess andd miccrosttructture, butt alsso onn prooper seleectioon annd coontrool off proocesss varriablles.译文：20.9 可机加工工性一种材料的的可机加工工性通常以以四种因素素的方式定定义：分的表面光光洁性和表表面完整性性。2、刀具的的寿命。3、切削力力和功

51、率的的需求。4、切屑控控制。以这种方式式，好的可可机加工性性指的是好好的表面光光洁性和完完整性，长长的刀具寿寿命，低的的切削力和和功率需求求。关于切切屑控制，细细长的卷曲曲切屑，如如果没有被被切割成小小片，以在在切屑区变变的混乱，缠缠在一起的的方式能够够严重的介介入剪切工工序。因为剪切工工序的复杂杂属性，所所以很难建建立定量地地释义材料料的可机加加工性的关关系。在制制造厂里，刀刀具寿命和和表面粗糙糙度通常被被认为是可可机加工性性中最重要要的因素。尽管已不不再大量的的被使用，近近乎准确的的机加工率率在以下的的例子中能能够被看到到。20.9.1 钢的可机机加工性因为钢是最最重要的工工程材料之之一（

52、正如如第5章所示），所所以他们的的可机加工工性已经被被广泛地研研究过。通通过宗教铅铅和硫磺，钢钢的可机加加工性已经经大大地提提高了。从从而得到了了所谓的易易切削钢。二次硫化钢钢和二次磷磷化钢 硫在钢钢中形成硫硫化锰夹杂杂物（第二二相粒子），这这些夹杂物物在第一剪剪切区引起起应力。其其结果是使使切屑容易易断开而变变小，从而而改善了可可加工性。这些夹杂杂物的大小小、形状、分布和集集中程度显显著的影响响可加工性性。化学元元素如碲和和硒，其化化学性质与与硫类似，在在二次硫化化钢中起夹夹杂物改性性作用。钢中的磷有有两个主要要的影响。它加强铁铁素体，增增加硬度。越硬的钢钢，形成更更好的切屑屑形成和表表面光

53、洁性性。需要注注意的是软软钢不适合合用于有积积屑瘤形成成和很差的的表面光洁洁性的机器器。第二个个影响是增增加的硬度度引起短切切屑而不是是不断的细细长的切屑屑的形成，因因此提高可可加工性。含铅的钢 钢中中高含量的的铅在硫化化锰夹杂物物尖端析出出。在非二二次硫化钢钢中，铅呈呈细小而分分散的颗粒粒。铅在铁铁、铜、铝铝和它们的的合金中是是不能溶解解的。因为为它的低抗抗剪强度。因此，铅铅充当固体体润滑剂并并且在切削削时，被涂涂在刀具和和切屑的接接口处。这这一特性已已经被在机机加工铅钢钢时，在切切屑的刀具具面表面有有高浓度的的铅的存在在所证实。当温度足够够高时例如，在在高的切削削速度和进进刀速度下下铅在刀

54、具具前直接熔熔化，并且且充当液体体润滑剂。除了这个个作用，铅铅降低第一一剪切区中中的剪应力力，减小切切削力和功功率消耗。铅能用于于各种钢号号，例如110XX，11XXX，12XXX，41XXX等等。铅铅钢被第二二和第三数数码中的字字母L所识别（例例如，100L45）。（需需要注意的的是在不锈锈钢中，字字母L的相同用用法指的是是低碳，提提高它们的的耐蚀性的的条件）。然而，因为为铅是有名名的毒素和和污染物，因因此在钢的的使用中存存在着严重重的环境隐隐患（在钢钢产品中每每年大约有有45000吨的铅消消耗）。结结果，对于于估算钢中中含铅量的的使用存在在一个持续续的趋势。铋和锡现现正作为钢钢中的铅最最可

55、能的替替代物而被被人们所研研究。脱氧钙钢 一个个重要的发发展是脱氧氧钙钢，在在脱氧钙钢钢中矽酸钙钙盐中的氧氧化物片的的形成。这这些片状，依依次减小第第二剪切区区中的力量量，降低刀刀具和切屑屑接口处的的摩擦和磨磨损。温度度也相应地地降低。结结果，这些些钢产生更更小的月牙牙洼磨损，特特别是在高高切削速度度时更是如如此。不锈钢 奥氏体体钢通常很很难机加工工。振动能能成为一个个问题，需需要有高硬硬度的机床床。然而，铁铁素体不锈锈钢有很好好的可机加加工性。马马氏体钢易易磨蚀，易易于形成积积屑瘤，并并且要求刀刀具材料有有高的热硬硬度和耐月月牙洼磨损损性。经沉沉淀硬化的的不锈钢强强度高、磨磨蚀性强，因因此要

56、求刀刀具材料硬硬而耐磨。钢中其它元元素在可机机加工性方方面的影响响 钢中中铝和矽的的存在总是是有害的，因因为这些元元素结合氧氧会生成氧氧化铝和矽矽酸盐，而而氧化铝和和矽酸盐硬硬且具有磨磨蚀性。这这些化合物物增加刀具具磨损，降降低可机加加工性。因因此生产和和使用净化化钢非常必必要。根据它们的的构成，碳碳和锰钢在在钢的可机机加工性方方面有不同同的影响。低碳素钢钢（少于00.15%的碳）通通过形成一一个积屑瘤瘤能生成很很差的表面面光洁性。尽管铸钢钢的可机加加工性和锻锻钢的大致致相同，但但铸钢具有有更大的磨磨蚀性。刀刀具和模具具钢很难用用于机加工工，他们通通常再煅烧烧后再机加加工。大多多数钢的可可机加

57、工性性在冷加工工后都有所所提高，冷冷加工能使使材料变硬硬并且减少少积屑瘤的的形成。其它合金元元素，例如如镍、铬、钳和钒，能能提高钢的的特性，减减小可机加加工性。硼硼的影响可可以忽视。气态元素素比如氢和和氮在钢的的特性方面面能有特别别的有害影影响。氧已已经被证明明了在硫化化锰夹杂物物的纵横比比方面有很很强的影响响。越高的的含氧量，就就产生越低低的纵横比比和越高的的可机加工工性。选择各种元元素以改善善可加工性性，我们应应该考虑到到这些元素素对已加工工零件在使使用中的性性能和强度度的不利影影响。例如如，当温度度升高时，铝铝会使钢变变脆（液体体金属脆化化，热脆化化，见1.4.3节节），尽管管其在室温温下对力学学性能没有有影响。因为硫化铁铁的构成，硫硫能严重的的减少钢的的热加工性性，除非有有足够的锰锰来防止这这种结构的的形成。在在室温下，二二次磷化钢钢的机械性性能依赖于于变形的硫硫化锰夹杂杂物的定位位（各向异异性）。二二次磷化钢钢具有更小小的延展性性，被单独独生成来提提高机加工工性。20.9.2 其它不同同金