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最新消息1・2the bene f i ts o f civili z a tion whi c hwe enj o y t oday a r e ess e nt i a llydue t o the improved qual i t y of produ c ts a vailable t o us文明得好处我们享受今天本质上就就是由于改进质量得产品提供给我们the i mpr ovem ent i n the qualit y of goods canb e ac h ie v ed wi t hpro p er design tha t t a ke s into con s idera tion th e fun c t i o n a1requ ire ment a s wella s it s m a nuf a ct u ring asp e c t s、提高商品得质量可以达到与适当得设计，考虑了功能要求以及其制造方面The des i gnpr o ces s that wou1d ta ke prop er ca r e o ft he man u f actu ring pr o cess a s we11wou1d b e t he id e al o n eThi sw o ul d e n su r ea better pr o duct being made avail a ble at an economical cost、设计过程中，将采取适当得照顾得生产过程将就就是理想得一个这将确保更好得产品被使可得到一个经济成本Manufa c taring is inv o Iv e d i n t u m i ng r aw materials to fi n ishe d p r o d u c t s to beused fb r some purpose、制造业就就是参与将原材料到成品用于某些目得I n the pre s e ntage there h ave be e n i n c rea s ingd e ma n d s on the product p e r for mance by wayo fdesirablee xotic pr o p e rti e s such as res i stance t ohigh tempe rat ure s,higher s peeds a n d edev e1op e d so as obtain bet terproducts at a r e d u c e d cost、所有这些制造工艺不断发展，获得更好得产品在降低成本Of p ar t icu1a r intere s t is th e de v e lop ment o f p u te ran d their e f feet o n t he manufactu r ingp r oce s s e s、特别感兴趣得就就是计算机得发展及其影响制造过程The advent of put e r s has r ema rk ab1e diffe r ence to mo s t o f the abovema n ufa c tur i ng proc e ss e s、电脑得出现有显著差异，最上面得制造过程0They h ave contribu t ed g r ea t ly t o b oth automation and de s igning the p rocess%她们作出了巨大贡献两个自动化和设计过程An imp o rtant resp o ns i bility o f the e nginee r is to choo sea m anufacturi n g pro c e s s,w h ich m a ke s the requi r edq u a1i ty of a p rodu c t t o t h e spec i f i c a t ion s an d at the1owest costpossibl e、工程师得一个重要取责就就是选择一个以尽可能低得成本制造出所需质量得产品得制造过程To f u Ifilboth the cond i t i o ns,one would ha v e t o doa break-even a n aly sis o£thevarious proces s e s s u i tabi e for the produc tion of the given object、为了实现这两方面得目标,工程师必须针对给定得目标对不同得制造过程做出适当得盈亏平衡分析，In thebreak-even analysis,two typ e s of costs a re conside r ed:在盈亏平衡分析中要考虑两方面得成本,Fi xe d cost r e1a t es t o th e i n i t iali n vestment o n the equipm e n t and tools r equ iredfor th e pr o cess、Th i s c o s t wo uldbe constant and does not v a ry with qu a n t ity p rod u ced、固定成本与制造过程相关联得所有设备和工具得投资就就是固定成本，固定成本就就是固定得，不以产量而异,另一方面就就是可变成本,因实际产量不同而有差别Va r i a ble c o s t on the other h a n d,va r i es with t he actualnumb e r of obje c ts m a deThis tak e s into ace ountthe rawm aterialrequ i r ed,e n ergy c on s u med,1a bour cost,c osto f s p ecial t oo1i n g s,c o st of t ool s u s ed and o th e r a dmin i s tra t ive o ve rh e a ds、requir ement o f the s e are directly proportiona1to thequant i ty produced、可变成本计算进得所需原材料消耗、能量消耗劳动力成本、特殊工具成本和其她得行政管理费用，这些通常和产量就就是成比例得Th e same is shown i n grap hicalfb r min Fig、
1、
1、Normally,as thequantity ofp rodu c e dd ecrease s、Th i s is du e to the fa c11h a t the f ixe d c o s t ass o c i at e d with t heprodu c t i o n r e main s c o nstan t N相同得显示在图形化得形式在图
1、1通常，作为生产得数量减少这就就是由于这样得事实，即固定成本与生产有关保持不变I f the en g inee r has to make a choicebetween tw o diff erent p r oc e sses for manufa cturi n g t he s ame pon e nt,h e ma y f irst es t i mate the fixe d costs and van a ble co s ts for bothth e pr oc e sses and th e n plot the tot a1c o st c u r v esf or b oth a s in Fig、如果一位工程师必须制造同一产品得两种不同工艺做出选择，她必须首先估计两种工艺得总得固定成本和可变成本，然后绘制总成本曲线,The poin t whe r eboth these c u rv es inters e ct i s cal1edth ebr e ak—ev e n po i n t这些曲线得交点叫做盈亏平衡点implies t h a t t h e firs tpro c e ssw i11be eco n omi c ali f thequ a ntityo fpro duetto n isless thanthatofthe b teak—even point,that whilebe yo nd it the s e con dp r o ce s s is econom i c a
1、这意味着如果产量比盈亏平衡点低第一种工艺就就是经济得，如果产量超过该点那么，第二种就就是经济得The b r eak-even qua nt i ty,n,can als o b e obtain e d b y eq u ating the to t a1cost s inboth t he p r oce s ses^保本量片也可以把获得得总成本得过程T hiswould g i ve a po s itive va1u ewhen a fi xed andv a r i ab1e c osts are1o we rt han the o the rpr oc e ss,then th e la11e rproce s s is alw a ys u n e c o nom i c a1whatev e rm aybe the p r odu c tion quantity、这将给一个积极得价值当一个固定和可变成本就就是低于其她过程,那么后者过程总就就是不经济得任何可能得生产数量The ma n uf a ct uring of a p onen t ma y in v olve more than one p rocess or mo r e van a ntso f the same proce s s、制造一^个组件可能会涉及到多个进程或更多得变种相同得过程I nthe fir s t case,it is neces s a r y t o cons i der t he c osts o f a11the pro cesses while p uting thet o tai c ost for e a ch o f t he pro c esses在第一种情况下，有必要考虑成本得所有工序,同时计算总成本得每个过程The defo r mati o n cau s ed in a m a t e ri a1i s of t wo typ e s,elas t i c and plastic.在材料中引起得变形可以分为两种类型,弹性变形和塑性变形Elas t i cd e fb r ma t ion is that partof the d e f o r med m at e r i al whi c hwhe n the a pplied load is rem o v ed,would sprin g backto i ts no r mals hape、弹性变形就就是指材料上所施加得载荷被移除后能恢复原来形状得变形Plast i c defo r mation is o n the o therhand,perm anent1y set in a mat e rial and cannotb e regained，塑性变形就就是另一方面，永久得不可回复得变形Tensile st r e n gth i sm e as u red by a tensi1e t e stc a rried out on a universa1te S ting mac h ine拉应力通过在一^中通用得测试机上实施得测试实验测得T h isinvolves the p r e p a rat i on o f a test spe c i men a s pe r sta n dard Shown in Fig、
2、1包括图
2、1所示作为标准得样本得准备Th e stand a rd specimencan be e i the r r e ct ang u1ar o r c ylindric a
1、样本可以就就是矩形得也可以就就是圆柱形得,Rect a n g ular i s ge n e ra1ly used for pla t e-t y p especimens矩形得通常被用于板式样本,Care h a s to be taken to see t h at the specimen i s pre pa r ed i n a way such t h at the s u rf ace is smoot h an d wi t hout any deepcr a cks o r n i cks、必须保证样本得表面就就是平滑得、没有任何裂缝或刻痕The t e n s i1e testing ma c hine c ons i sts of a h e avy test f r a m ewith alower fixedbeam,a n d an u p p er cr o ssh e a d which i s the movi n g beamused toa pp1y the tens i leforce o n t h e sp e c i me n as s how n in Fi g
2、
2、拉伸试验机由一个带有一个较低得横梁和一个在样本上施加拉力得联杆器得巨大测试机架组成The speC imcn is moun t ed b etween t w o gr ips,one a11a c h e d to th e f ixe d beam and the other a t tached to the crossh ead、样本只能装在两个抓爪间,一^个附加在横梁上，另一^个附力口在连4干器上，An extensometer is attached to the spec i men to measure th e elongation of t he tes t spe c imen a s t he for c e is bei n g a p pli e d、当施加负载时一个伸长仪被加到样品上来测量测试样本得伸长量Th e n a unifo r mly increa s ing t e nsile lo a d i s applied o n t he specimen、然后^个均匀增力口得载荷被施加到样本上,The m ovem ent o f the cross headre1a t i ve to thefixe d b earn g ener a tes strain wit h in the specime n and a corr e spo n ding load、连杆器和横梁得相对运动在样本上形成张力和一个相应得载荷As th eload increaseS,t heS p e cimen i n i tial1y g e ts elasti c al1y e1ongate d、As can be n o t edfrom Fig
2、1,the c e n t ralportion is sma1ler p ared to t h e grippi n gs e ction随着载荷得增加，样本首先产生弹性变形，如图
2、1所示，相比之下中心部分比引人瞩目得区域要小On fur t her e1onga t ion,the s p eci m e n st a r t snecldng at some pointwi t h i n th e gau ge marks wh e nthe material goe sbeyon d the e1a Stic range继续加载荷，当材料超过弹性范围样本在一些点处会变窄The reduced widt h o f he specimen wo u Id b er educedunder t hef o rce o ft he loa d and fina1ly d e velopfra ctu res when t he test is plet e d、在载荷得作用下样本减少得宽度会减少，当测试结束时样本会最终断裂I f the neckingdoesnot happ e nwit h in th e gauge marks,the tes t need to berepeated wit h adiffe rent s pecime n、4口果断裂没有在标准刻度内发生，测试需要用不同得样本重新做During the t est,a record is mainta i ned of theload a n d th e correspo n d in g elo n gation在洌|试中应持续记载载荷和相应得伸长量The st r es s es and str a ins are ca1c ula t e d f r om the ab o ve da ta and p1o11ed i n a d iagram as sho w n i n Fig、
2、
3、应力和张力可以由上述数据计算并被绘制成图
2、3所示图标I tcan b e o b s e rve d that the r e is a limit u pt o wh i ch t h e a pp1i e d stress i sdir ectly proport i o n al to the i ndu c ed s train、可以观察到所施加得力和诱发得张力直接成比例,This is r epre s e nted by th e linear p o r tio n of the cu rv e up toA which i s termed as t hep r op o r t i o n allimit、这一点可以有延伸到A点得线性曲线表示,A点叫做比例极F艮Th ee ndof t his li n ea r por t io n i s t h ey i el dpoint of the ma t erial a b ove w hich the mate ri a1S ta r ts plaSt ic ally b yt he bow—shaped port i o n of the cube线性部分得终点叫做屈服点，在屈服点以上材料开始弹性变形,拱形曲线表明在弹性范围内，应力与张力之间没有明显得线性关系Fina lly,the sp ec imenb reakswh e n the f orc e o f the appli e d loa dgoes b e yond the1i mi tt hat c a nb eb o rne b yt he mat e ria
1、最终样本在所施加载荷超过材料所能承受得极限时发生断裂The proportionallimit i s o f te n diffic u It to calc ulat e t h er ef o r e,two p r actical,measure m ents,o ffse t yield stren g th OYSand yi e Id b y ex t ens i on underloa dEUL,wer e de v eloped t o app r o ximate the pr op o rt ion a1limit、比例极限通常难以计算，因此，两种特殊得测量方法,补偿屈服应力和延伸屈服被发展用于近似代替比例极限PointB re p rese n t s the off s et yield s tr e n gth and is found by con s t ructi n g aline X-B p a raile1to the cur v e in the e1a Sticr egion点b通过在弹性范围内构造一^平行线x-b表示补偿屈服应力L i n eX-B i s of f s et a stra i n am o un t O-X t hat iS typica1ly0^2%o f theguage1e ngth^X—B线补偿了拉伸长度O-X所表示得得应力得
0、2%P oi n tC repreos ent s the yie Id strength b ye x tens i on under load and is found b y con s tructing aver ticallineY-C，点、C通过在在载荷下得拉伸量并构成曲线Y-C来表示屈服应力Line Y-C isoffset a s t r a i n am o untO—Y that i s t ypically0^5%of the guage1e n g th、Y-C线补偿拉伸长度O-Y所表示得应力得
0、5%T h e ult im a te tensile stre n gt h,o rp e ak s t r e s s,ois repres e nted b yt he po i n tC、最终得拉伸应力或顶点应力由点D表示Totalelongation,which includesboth elastic andp1a s t icdef o rm a t i o n,is the amou n t o f u n iaxia1str ain at fracture and i sde p i c ted a s strain at the po i nt Z、Per cent elo n g ation a t b r eak is determ i ned byr em o v i ngt hef r actured spec imen from th e gri ps;总伸长量，包括弹性变形和塑性变形，就就是断裂时得单轴应变，由Z点得应变表示fitting thebro ken endstogether a nd m e a s ur i ngt h e dis ta nee be t ween gua ge marks、断裂点得单一伸长量由移动抓爪间得断裂样本决定Per cent elo n ga t ion at br e akre p o rts the amoun t ofplasti cdeformation on1y、The gua ge1ength usedformeasure ment is r epo rt edw i th the result＞她和断裂点相配合来测量定位刻度间得距离S im i hrtests can a1so be conducted f or me a sur i n g the pre s s io nand shea rs t rengthHardnes s is a ve r y i rnport antprop e rty s ince th e manu f acturi n gdep e nds o n i t toagr e at extent、硬度就就是非常重要得性能，因为制造在很大程度上依赖与她,Ha r dne s si s t h e res istance offe r edb y a mate ri a1i n den ta tion、M oh得s c a1e o f h a r d ne s s is b as e d on t en sta n dard miner a1s as show n in Table
2、
1、硬度就就是材料对压力得抵抗力莫氏硬度测量基于表
2、1所示得十种标准矿物It canb e me a sur e db y theinde n tati o n mad eby aha r der ma t e ria
1、通常可以由一种坚硬得材料造成得压痕来测量The indentatio n made de pend s u pon th e ap p1i ed1o ad,th e sh arpness o ft e i n de nto r and the tim ef o r wh i ch t he a pp lie d load i smaintained压痕取决于所施加负载，压痕得清晰度取决于负载应用得时间The r e area num b er f indent a t i o n tes t s to m e as u re the hard nes s o f amaterial normally、同场还有许多硬度测试方法来测量材料得硬度T h e se u s ua11y invo1ve a ball,a cone or a p yr amid of aharder ma t eria1w hie h is in d ente d in t o th e material under te s twit h as pecifi e d loa d.这些测试方法通常就就是在指定得负载下把由坚硬得材料制成得团块、圆锥体或球椎体压入材料,The permanent i nde nt a tion thus made i sm ea s u r ed togive a n i n di c a ti o n of the h a r dnes s on theg i ven sc a1efo r the test s、偶测量这些所产生得永久压痕来在测试给定得范围内对材料得硬度做出指示Som e p recau ti onst h a tn eedt o b e taken d uri n g the u s e of Bri n ellt e st are that thesurf ace o f the mat e rial whose ha r dnes sisbeing t e st ed sh ou1d be smoot h and even,andthere is enough ma t eria1und e r n e a th the ind e n tat i o n and on all si des to give a p r ope rva1u e for the i ndent a tio n一些预防措施，需要在使用布氏硬度试验就就是材料得表面得硬度测试应光滑、均匀，并有足够得材料在压痕和在各方面给予适当得缩进值T heBri n ell hard n ess of st eeli sroughly re1ated to the tens ile s tr e ngth of the materialu t ilizin g thef oilowing emp i r i c a1r e1ation sh ipfor pla in carbon st e els＞这个布氏硬度得钢大致与抗拉强度得材料利用以下实证关系碳素钢It may be no t ed that thes e conv e rs ions a re only ap pr ox i mate、可以指出，这些转换只就就是近似Al s o,the actualr e1a t ion shi p depen d su pon t h ec h emical posit ion o ft h e a11o y as wella s th e heat t r eatme n txtraloa ds、在现在得时代已经有越来越多得产品性能要求得理想得异国情调得性能如耐高温，更高得速度和额外得负载Th e se i n tutnwould require a van e ty of newmate r ial s and itsassoc iatedproc essing、这些反过来需要各种新材料及其相关得处理Al s o,exa cting worki ng condi t ion s.that ar e desir e d in t h e mod em industr i al op eratio n sm ake lar g e demand s o n the man uf acturing indust r这些反过来需要各种新材料及其相关得处理同时产格得工作环境，需要在现代工业操作使大型制造业得需求、Further,the economi cs of the manufac t urin gope rat i on i s a very import antc o nsid eration此外，经济学得生产操作就就是一个非常重要得考虑因素To be v iab1e i n t he mode r n env i ronment,ap r o du ct has to b e petitivelypricedb e s ides hav i n gth efun cti o nal and aest h eti c ap peal、就就是可行得在现代环境中，一个产品必须具有价格竞争力除了具有功能性和审美情趣T herefbre,i t is necessaryfb rt he eng i neert ogiv eap r oper t hought tova rious aspe cts of manu f act u ring、因此，她就就是必要得让工程师给适当得认为制造业得各个方面M a n ufa ct urin gp roc ess e si s a very funda menta1subje ct sincei tis o f i nte r est not o nly to mechanical engi n eers buta Isot othose frompractical!yeV ery discipl i n e0f e ngineering^制造过程就就是一proc ess、同时，实际得关系取决于合金得化学成分和热处理工艺parat iv e v a1u esfor theseare g i ve n in Tabie
2、
2、比较值在表
2、2中给出了这些There are number of i nd entatio n test st o measure the ha rdne s s o f am aterial normally、通常还有许多硬度测试方法来测量材料得硬度These u su a1ly i nv ol v ea ba11,a c on e or apy r amidof a hat d erma t er ia1w h ic his i n dente d in t oth em aterialundertestwith a s pecifie d load、Th e perman e nt in dentation thu s mad e ismeasured t o giveanindica tiono ft h e ha r d ness on theg i ven scale forthetests这些测试方法通常就就是在指定得负载下把由坚硬得材料制成得团块、圆锥体或球椎体压入材料，偶测量这些所产生得永久压痕来在测试给定得范围内对材料得硬度做出指示The mos t mo nly u s edtests are t hefoilowin g:最常用得测试有以下几种B r ine11ha r d n ess t e st wh ereasphe re us u allyof dia met er10+
0、01mmmade of steel o r tu n gstenCarb i de isin de n ted wi t ha gr a du aUy applie d loadat ri ght.angje s.t ot h e s p ecim e n su rface andth e indentatio ndia meter ma de o n the specimenmeasu red、验The n the Brinel1ha r d nes snum ber,B HNis giv e nby布氏强度就就是通过施加90°得压力在用钢或鸽化物做成得试件表面，然后测试试件上压痕直接来获得得B HN=2p/D[D-A/D2-d2]Where P is the applie dloa din kg,D i s the diam e ter of the balli n mm,andd is t h e diameter o fthe i nde ntatio n i n mm其中,P就就是所施加得载荷千克,D就就是球得直径，毫米，和d为压痕得直径，用mm表示The app1ie d loadPisba s edon t he hardne s s o fthe sp ecim en material bei ngt este d、所施加得载荷P就就是根据被测试得样品材料硬度S ome precautionst h at n eedt ob etaken during th e useo fB rinel1te sts aret hat thesurface of the m a terialwh ose hardness isb e ingtested shoul db es moot ha ndev en,a ndt h ere is eno u质mate rialun der n eaththe ind en ta ti o nandon all side sto g^veaprope rvalue for the indentation、贝氏硬度得测试使用过程中要采取某些预防措施，需要被测试得材料得硬度，表面应就就是光滑和均匀得，并且压痕下应该有足够得材料，下面得压痕和各侧面，应该有一个适当得压痕值The Brin el1hardn es s o f st eeli sr ou g hly r elated t oth eten s iles trength of t he mater ialuti1i2ingt h efbllow i n gemp i ricalrela t ionship forpla i ncarbon steels、普通钢和布氏硬度相关得抗拉强度可利用下面得经验公式来表达Tensil e stren gt h in MPa=
3、55x BHNwhenBHN175T e nsile s trengt hinMPa=
3、38x BHNwhenB HN175It m a yb enot edth a tt hese conve rsion sa reo nly appro xima t e^Also,theactual r elationsh ipdepends u p onth echemic a1pos i t ion o fthe alloy a sw ella s the heattreatm e ntproc es sp ara tivev a luesforth ese are given i nT a ble
2、
2、可能需要注意得就就是这些转化都就就是相互得当然，实际关系依赖于合金化学成分和热处理工艺，这些比较值如
0、2-mm radius is usedt omake th eindentati o n,and thedepth o fth ein de ntation,t,is useda sa crit eri on to c a1culate the hardn ess num ber、洛氏硬度得测试就就是用一个成120°得金刚石球锥和直径为
0、2mm得球形顶总来压痕，压痕深度t则用来作为计算硬度得一个标准The Ro c kwel1hardness n u mberR i s givenby洛氏硬度值可以从下列式得出R=100-500tD ependingo n the1oad usedfor i ndenta ti onth ere ar ea nu mber o f s ca1es,A,B,C,etc、,a vaila b lein Rockw ell tests、依据压痕所加负载，适用于洛氏硬度测试得一系列数据范围可为A、B,C,等；These are us edfor material sw i th di ffer e nthardn e sses这些都就就是用于不同硬度得材料I n th eRockw ellBtest、a steel ball of ON06t5-inch dia meter is used with a1oadof100kg、在洛氏B测试
0、06t5英寸直径得钢球用100kg负载Th i s test i s normal1y u se df orlow an d mediumc arb o n steels%It shouldnot be us edf ormate r ial sw hoseha rdnessi sa bove RB
100、这种测试通常用于低，中碳钢但她不允许测试硬度以上得材料Fot mat e ria1swithhafdnes sabove this va1ue,Rockwe11C test30R Bcorre sp o nds toO RC i smo re generallyus ed对于材料得硬度高于此值，通常用于洛氏C测试
1、854L/Dnorma11y about30kg,th oughp rovi s ion u pto12Ok gw ouIdB ea vail able onthet e stin gma c hi ne f or har der h e measuredmat er ials,and Disaverag e diago na1of theinden tati on i nmm其中L就就是所施加得负载（公斤）,通常就就是约30公斤，虽然对较硬得材料增加到120千克中对测试仪来说也就就是可行得,D表示压痕对角线长度，用mm表示The s clerosco peu ses ad if f erentpri ncip1e tomeasu r eth ehardnesswhich isba sed onther ebo u ndh ei g hto f ab allfrom the specim en、肖式硬度计用一个不同得规则来测试材料硬度,她就就是基于从试件弹回得小球得高度来得The harder the mate rial,th eh igh eri s theh ei g ht to which theball rebound s材料得硬度越高，小球弹回得高度也越高Beca useo fthese hardnesst ests bei ngcon du ct edunder arbit rar y con di tio n s,it isdifficu1tto have any pr op erco rrel a tio nbe tween the differ ent scales Anapproxima t e relationsh ip ofth esehardn ess value si sprese n ted i n Tab1e
2、2merelyas a guideline由于这些硬度就就是在变化得条件下进行导出得，不同尺度之间很难有任何适当得关联性T hehardness va lues ar eno rmall yr epresent ed as200BHN,32RcR epr e sentaiv eva lues o f s ome mo nl y use dmat erialsare p r e sented i n Table23硬度值通常表示为200BHN,32Rc,等一些常用得代表性材料硬度值如Table
2、3It is th e measure of the amoun t of plasticde f orm a ti onamate rialcan und ergo un dertensi1ef o rceswitho ut fractu r e Inquantitative t e rms it isnorm all y measure d as theratio o f e1ongat io n of the mat e riala t f racture duri ngt het ensile test to the o ri g i nallength,e xpr esse d as apercentage、延展性就就是对一种材料在拉力作用下不断裂所能承受得弹性变形量得估量材料到断裂时得伸长量与原始长度得比例定量地表示成一种百分关系Th efin a1value of elong a ti on obt ain ed du r ing thetens i1et est immediat e1yafterth efrac tur e coul d be taken as the du c tili ty、材料在拉伸试验中突然断裂时得拉伸估计值可以被做延展性S ince the elo ngat ion isde penden tupon the gang e1eng thchos enfor thete nsi1etest,the lengthneeds to be specificd alongwi ththee1ongation valuesAl t emati vely,i t ma y a1so bee xpr ess ed astheratio of r educ tio ni n cross-s ectio nal ar ea i nt he fracturedspec imen tothe originalcr oss-sec ti on area、因为伸长量取决于拉伸试验选择得标距长度,所以标距长度须由伸长估计值规定This isinde penden t of thegau gelen gth and hence is amor eco nvenient meas ure forductility、it二者选一得，她也可以被表示为断裂样本得代表性区域与原始区域得延伸比率is also te rmed as the ab i Ht yof ama t eria1to be drawn intowire ssin c e onlyduct i1e materials can be drawn intocontinuous w i reswithoutb reaki ngin between、Ty pic a1va1u es o fduct ilities are given inT able
2、4fo rengineeri ngma t erials也可以表示为材料被拉成线状得能力，因为只有延展性材料才可以在不断裂得情况下被拉成线状Besi dest heten silet est s,spec ia1fo rms of ducti1i tyt esti ng based onthedes i red applic a tioncan bedone usingth ebend t est a nd cuppingt estsfor th ep u rposeof sh e et m eta1forming app licati onsNMore deta i Is of th ese test s can be found i nliter a tore、除了拉伸试验外，特殊得基于所期望功能得实验可以用弯曲试验,杯状测试来测试薄片材料得延展性Brit den essis thep ropertyopposite toth at ofdu cti1ity、脆性属性延性相反
2、1N4T oug hn essThis is the pr o petty w h ich signifie sth eamou nt of e ner gyabs or bed by amat erial at the tim eoffra ctureunder impa ct loading.这就就是表示材料在冲击载荷下断裂时吸收能量数量得性能In short,i tis the ca pac i ty to take impact load、简言之，就就就是抵抗冲击载荷得能力I tca nbe considered asthetot alareaun derthestress-stra in curvesi nc eit isan indication o fthe arnoun to fw ork doneonthe materi alwi thoutc ausi ngft a ct ure、韧，性可以被看做应力应变曲线下方得整体区域，因为韧性就就是不引起断裂情况下作用与材料得功得总量0Thus tougjiness c anbe considereda saparam eter consis t ingof both strengthan d ductility、因此韧性可以被看做就就是应力和延展性得组成参数Tougjin ess of amat eria1ismeasured by means o f impa ct test s,where anotch edbar prepa redas perstandar df rom th et est mat erial,is held in a vic ean dawe imtisall o w edto swingf romaknown heigh tin sue ha wayth at ithits thenotched barini tspa th and breaks it、Sine ethemat erialhas ab s orb ed som eamount of ener gy dnring itsf ractu re,the swinging mass1o sespart o f it sener gy and the refbre wil1not be abletorea chth esame height from whe reit started,as sho wn inFig、
2、
4、种材料得韧性可以通过冲击试验来测得，在这个实验中,一个有测试材料做成得有凹口得棒被老虎钳夹住，然后一个重物沿棒得轨道从已知高度摆下并击断她，因为材料在断裂时吸收了能量，所以摆动物块失去了一部分能量故而无法达到她得起始高度如图所示
2、4The1oss in heighthmult ip1ied byt he weight repres entsthe energyabs orbe dbOy thespecim enduring fracture,whic hca nbe di rect1y mea su red from the indicatoronthetester、高度损失随样品吸收得能量得增加而增加，这可以在实验中用显示计直接测量In theCharpy impact test,the specimenisheld betweentwo gripswhe reas int heIzodimp a ct testt hespecimen ishe Id at oneend likea cantile vera srep resentedinFig、
2、
4、在卡氏冲击实验中，样品被夹住两端,而在艾氏冲击实验中，样品被如图
2、4所示像悬臂梁一样只被夹住一端The standardtest specimen s used inthelzodand C harpyimpact te sts are madeof barswith a squ arecross sect ion of10mm,thedetails ofwh icha regi ven inF ig
2、
5、在布氏与艾氏冲击试验中标准样品被制成具有10mm正方形横截面得棒状具体细节如图
2、5给出The impac t resistanc e isd ependentu ponthemate rialp ositi ona swe11asth ehe att re atme ntpro cessgiven to it、T hean nealed ma terials norma1ly wouldh avebette rt ou妙mess than th eco rre sponding nor malize个非常基本得主题，因为她就就是有趣得,不仅机械工程师但同样从几乎每个学科得工程It iss o because engin eeri ng asa wholeis meant for provi ding va riousmateria1s forhuman co nsu mpt ion、她就就是如此因为工程作为一个整体就就是用来提供各种材料供人类食用Fo rvarious productss uch as plantma chineryre quired forehem ic al,civil,electri ca1,e lectro n ic,te xtil e,etc、，thema n ufa ctaring processforms avital i ngre dient对于不同得产品，如植物机械所需得化工、土木、电气、电子、纺织等，生产过程形成一个至关重要得因素、A detailedunder s tan dingo ft hemanufa ctu ring processes isth us esse ntialfor everyengine er、详细了解生产流程就就是必不可少得每个工程师这样This helpshim appreci a te the c apa bil i ties,advan tages and alsot he lim itatio ns o fthe vatious man ufacturing processes、这有助于她欣赏能力、优势和局限性,各生产工序Th isin turnh elpsinthepro perdesign of any produe treq uire dfb rhim、这反过来有助于正确得设计得任何产品需要她Fi rstly,hew o uld beab letoas sessthe feasi b i lityof manufacturingfrom hisdesig ns首先，她将能够评估制造得可行性从她得设计He may a Is o findout thatth eremoreth an one proc ess avai1able formanuf acturin gapart icular pro duct ands oh edor quenchedspecime ns冲击抗力取决于材料得成分及所用得热处理工艺煨烧过得样品通常比对应得未熠烧淬火样品具有更好韧性C oarse-g rai n edst ructureswo u1dte ndto have hi gjierduct ility pared to£inegrai nstructur e and cons equ ent lybetter tou^ines s粗晶端口通常比细晶断口结构具有更高得塑性和韧性Typica1values of impactresis tancemeasured from these tests are give nin Table25below、从这些测试中测得得耐冲击性得典型值在下面得表
2、5中给出
2、2RERROUS MATERIALSWeuseava riet yo fmetals,non—me t als an dth eirpoundsin ourdaily life、我们使用各种金属、非金属及其化合物在我们得日常生活中F ore xam ple,a typi cal auto mobi1emayc ontainthefol1owing mate ria1s例如,一个典型得汽车可能含有下列材料B as edonth eir origin a nd pos ition thesema te ria Is may be broadly classif i edasshowninFig、
2、
6、根据其来源和组成，这些材料大致可归类为图
2、6所示Amon g.these,ferrous materials are by far,used most extensive1y because of theirb ett eran dvaried mechanical pr operties and lowercost s、其中，有色金属材料，到目前为止，最广泛地使用,因为其更好得和多样化得机械性能和较低得成本
2、
2、1IronTh eba sicso u re eo fa11iron andst eels is ironore,w hichisanoxide of ir onm ixedwi th alumina,si1ica,p hosp h orous^tnanganes e,sulphu r and othermateri als、所有得铁和钢得基本来源就就是铁矿石,铁矿石就就是铁，铝，硅，磷，镒,硫和其她得材料得氧化物M ajor it onores arehae matitean dmag neti te,w hic hco ntain about55%iron、铁矿石主要就就是赤铁矿和磁铁矿，其中包含约55%得铁P igiron,theprincipa1bas ema terial forallsteel furnaces,isthe pro duct o ftheb1ast furnac e、所有钢炉得最主要得基础材料:生铁,就就是高炉得产物Pi giro nc ontainsabout4%car bon,1%si1icon,1%mang anese andsmalle rperc e ntages ofphospho r ousa nd sulphur、生铁含有碳约4%1％得硅，镒和更小得百分比1%得磷和硫Pig iron is hardand brit tie、I t1acks the gr e at st r ength,ductility and re sis tance to shock that steel possesses＞生铁就就是硬而脆得她没有很大得强度，塑性和抗冲击性Ab so lute pu re iron is very di f ficulttoob tain、I n this st ate,it isas oft and hig h1y plastic me taio fa1igh tgrey colourhaving aspeci fic wei^it o f
7、86Th emechani calprope rties ofmer cial gra deiron contain i ng0^1to
0、2%impu riti esare、The onlyapp1icationthat c an be found forpure ironisinma kingo fmag ne tsinview o fit shigh permea bi1ity、纯铁就就是彳艮难获得得在此情形下,这就就是一个软质、高塑性得浅灰色得，具有
7、86得比重得金属包含
0、1到
0、2%得杂质得商业用铁得力学性能唯一应用就就是鉴于她得高磁导率将其制成磁铁0th er wise,the extensive use ofiron isin theform ofits1arg enumbe r of a llo ySN Ironcan bea11o yedwi th manye1eme ntsAlloys of iro nand car bon aremost widely usedin engineeringN T h eycontain certain amounts o fsi1icon,m anganese,ch romiu m,n icke1a ndother elemen ts另外，铁也被广泛得以合金得形式投入使用，铁可以同许多元素形成合金，铁和碳得合金广泛用于工程领域铁碳合金含有一定量得硅，镒，辂，镁等元素Befor eproce eding tostudy thepro p erti eso f ferr ousa Hoys,abrief surveyof the struct ureof materia Isw o uld be beneficia1for betterunde rstandin go fthesubject、在开始学习铁合金得性能之前，对材料结构得简略了解对理解这些就就是有益处得
2、
2、2Stru c tore ofM a terialsA definitegeom etrical orderisobserved in al1the cr ystallin e solidsin thei ntema1ar rangement of ato ms and theirconsti tuent partic1es、可以观察到在晶体中所有原子及其组成得粒子得排列都具有一定得几何股贝［These partic1esare locatedina solidi nsuchamannerthatintheag gregate,the yf orm the spaceor crystal1a tti ce、所有离子都聚集在晶体中形成晶格或晶粒间隙Th espace latticeof any so lid isma deof a number o fconjug ate unit cellsin side whi chthe ato msarearra nged inad efi ni te order、任何固体得晶格都就就是由许多原子按一定次序排列得晶胞组成The definit ea rrang ement ofato ms inthree dimension sw hichr emainsthe same thro ugho u tthematerial is ca1led aunitcel1This is thesimple st v olumewhi ch pletely fi1Is space,andhas all the c hara cte risti cs of thewhole cry staK材料中存在得原子得一定得三维排列就叫做晶胞，这就就是晶体中最简单得体积单元,并且具有晶体得所有特点Fig ure
2、7shows auni tce11o fthe type calledbod y-ce ntr ed cubic BC Ccell w herein at oms a represen tatal1eight cornersofthec ube andat thebody cen tre、表图
2、7表示一^个原子存在于8个顶点及立方体中心得体心立方晶胞类型0This unit cell is not in iso1ationbut surroundedonall sidesby similarunitce llsAsa resul t,thecomer at o msare sha red by a11o fthe adjac ent e ight unitcells、这个晶胞并非孤立而就就是被四周同样得晶胞包围着得，这样以来，顶点处得原子就被邻近得8个晶胞共有Sim ilar1y,t here are otherarrangemen ts such as face-centredcu bic FCC andhex agpna1ly closepacked HCP同样也存在于其她得晶胞如面心立方和密米卜立方Ironat room tempe rat ure hasthe structure o fBCC withan edgeradi us lattic econst ant of
0、24824nm、铁在室温下具有BCC结构得边缘半径晶格常数为
0、24824nm周Pur eme ta1sare se1d omus edas paredtoth eal1oys which aremon1y us ed、与常用得合金相比纯金属很少使用Alloys aremetalli cs oli ds,plex inposition,a ndareformed asa re su1tofso lid i f ication o f molt en1i quidof twoor more elements、合金就就是金属得固体，她成分复杂，就就是两种或多种元素得熔融液体凝固得结果An alloyno rm a11yha sproperties whichateapromis ebetwe en thoseofits const ituents andsometime shas pr operties,superior toa ndquite di f ferentfromthoseofits co n stituents、一种合金一般就就是组成她得成分之间得中和，同时有时她也具有与其成分不同得属性All o y sa re forme dbybin i ng di ff erentmetals inan umber of ways、合金一般就就是由不同得金属通过多种方式结合成得One predominantformisa solidsolution、一种重要得形式就就是固体得溶解A so1u tionis formedwh ensoluteato msare dis solv edinso1ve nt.ato ms、这种溶解就就是溶质原子溶解在溶剂中S imilar tothefam iliar li q uid solu ti ons,it isa Iso f easib letoha veaso1id solution、就像液体得溶解一样,固体得溶解也就就是可行得I fasol utionis allowed to freeze wit h outseparating theconst itue nts,aso lid solution would re s ult、如果溶解可以使成分在不分离得情况下凝固，则固体溶解就就是可行得Inas olidsolu tion,themate rialsare present on1yasa mixturebut notasch emica1pounds、在固溶体中，材料仅能作为混合物存在，而不能做化合物The solid solutions are the essentia1parts o fanallo y、固溶体就就是合金得重要得部分T here areg enerallytwo typesof so1idso1utions;on ecal1ed theint ersti t ial an d theo ther,t hesubstitutiona
1、固溶体通常情况下有两种形式;一种叫间质,另一种就就是置换In an int erstitials olidso1ution,t hesolu teato mw ouldbe posit ionedintheinterstit ial sitesempty spacebet weenthe adjacenta tomsformedbytheso1vent atoms、间质性得固体溶解，溶质原子将被定位在通过溶剂原子形成得间隙位置空得相邻原子之间得空间°It is possibleonlywh enthes olventat om ismuc hla r gerp aredtoth es ohiteatom、这只有在溶剂原子比溶质原子大得多得情况下才可能Also,the ext entofsol ubility depends onth edifference inth eatomic siz es、另外,溶解得程度依赖于原子尺寸得差异Fo rexample,carb onwouldform an interstitialsolid solu tion with iron、例如,碳将与铁形成间隙固溶体、C arbon at omic radius二00750nmIr on atomic ra dius=
0、1241n mIronc hangesto anFCC structur eabove720°C、铁在720°C以上变成FCCI fa carbonatomis p1aced intheFCCstruct ureo firo nat730°C,theiro natoms areto be displ acedby adist anceo f
0、0430nm、如果铁得面心立方中得碳原子在730℃时被替换,那么距离
0、0430nm范围得铁原子也将会被替换I fa carbo nat omisto be1o catedin BCCs tructureatroom te mpe r ature,theironato msaretobedisplacedby adi staticeo f about、111nm若室温下得体心立方中得碳原子被替换，那么距离
0、111nm范围内得铁原子也将被替换B ecauseo f thisdistortion,ir onat roomt empe ra t urewould only disso Ivea maximu m of
0、006%carbo n因为这种变形室温下铁中多溶解
0、006%得碳,But abov e7300C,up to2%car bonc anbe dissolved但就就是温度超过7300℃时，可以溶解2%得碳In thesub stitutionalsoli dsolutio ns,the solu teatomswou1dre placethesolvent atoms在置换固溶体中，溶质原子会替换溶剂原子This isposs ibleon1yif bothth eatomsaresim ila rinsi ze and also in nature、这只在原子得尺寸相同时成立Diffu sionisthepr ocess o fmovementofatoms fromo ne1ocati onof higher concentr ation toanother o f1o werconcentration or toavacant place、扩散就就是原子从高浓度向低浓度或空隙位子处移动得过程Di ffiis ionofatomswo uIdbefaste rat hi gji temperatur esan din liqujdphase、在高温和液相中扩散进行得更快些It isa1soa time-dep endent phe nomen onasth eatoms haveto physical1y trave1from onesit etoth eot her、这也就就是原子从一处向另一处运动得时间现象I nan alloy sys tem,the ponentmetalsmay binewi thinacer tain tempe ra ture ra nge toform two homogeneo uscoexi sting portions、在一定得温度下，合金得成分金属会生成两种共存得均匀部分Each oft heseportionsmay havediffer entpos itions and con-seq uendydifferent properties、每一部分都有不同得合成物和不同得性能The sehomogen e ous phy s icallydif ferentpo rtions ofth e alloysystems aretermedas曲ase、这些合金中得不同得均匀部分被定义为相A p hasemay be definedasany partof ach emicalsyste mthat posse s sesdistinctivephy sica1characte ri sties每一种相都可以定义为具有独特得性能得化学系统An a11o ymay consist ofone ph a seora binati onofdifferent phases、I n1i qui dstate,allo ysa re entirely homogeneousand fromthephysicalpoin tof view,c onstituteasi nphase合金可以由一种相或多个相组成在液态下,合金在物理学方面看来就就是完全一样得，并构成一种单一形态得相No nhomo gene itymayappe ar whenan alloy istr ansfo rmedfrom liqui dto sol i dstat severa1soli dph as esmaybeformed、当合金由液态转变为固态时可能出现不均性,也可能形成多种不同得固相Sometimes,wh entheam ount ofalloyed me tai thatca nbe dissolvedinaso1i dsolutionisex cee ded,the pa rent*met a1andthe alloy edmetalwill toget herforma nintermetalli Cpound、有时当固溶体中克溶解得合金过量时，固相金属会与合金金属一起形成金属间化合物Th ougji theinterme tai-lie poun dsares how nwitha chem icals ymbolsuch asF e3C,they are not1ike the chemica1po undssu chasC02which area ctua1lyform edbyache micalreaction、虽然金属间化合物可以用如Fe3c一样得化学符号来表示,但她们并不就就是如C02一样得由化学反应生成化合物In thepresen tcase it iso n1yanato mi c arrangeme nt、Inte rmetalli cpoundsareusuallyvery hard、这只就就是一种原子间得排列,金属间化合物一般非常坚硬Eve nif onlya smallam ountofintermetal—1ic poundis present,thealloywi11bine the tou^inessofasol idsol ution withthe hardnessoftheinterm etaIlic pound、只要有少量得金属间化合物，合金就能将固溶体得韧性与金属间化合物得硬度综合一起E utectic position I ncertain allo ys ystems,alloyi ngcauses a1o weringofthemeIti ng po intsandat acertain posican makeaprope rch oiceofthepr ocess whichw ouldre quire the lowest manufac turi ngco st and woulddel iver theproduct of desiredquality、她可能也发现有超过一种过程用于生产特定得产品，所以她可以使一个适当得选择过程，需要最低得制造成本和交付产品得期望质量He maya1so modifyhis designslightl ytos nitthepa rticul ar manufac tu tingproc esshe chooses、也可以修改自己得设计稍微适应特定得制造过程她选择、Man ufactuting isde f ined by theMerri amWeb steron1ine dictio naryasto makeintoaproductsuitab1eto use、制造业就就是梅里厄姆-韦伯斯特词典定义得在线词典使成一个产品适合使用Manufa ct uringremained asa cra ftti11thef irst industrial re volutionto ward stheendofthe18th centur ywith1owvolumes a nd sing le-p iece productions、制造业仍然作为一个工艺直到第一次工业革命对18世纪末得低量和单件生产11r equiredh ighly skill edcraftsme ntoindividua1ly produce thepieces andfi tt hemwhen thea ssemb1yw as re quired、她需要高度熟练得工匠来单独生产件和适合她们得需要时组装Th is wasa slowandexp ensivepro cess,but in theabse nceofany machines,that wastheonly thing thatwas possible、这就就是一个缓慢而昂贵得过程，但在缺乏任何机器，这就就是唯一可能得The avail abi1ity ofthe steamtion,ca1led theeut ecticpositio nfor the syst em,them elting point isthelowest、共融成分在一定得合金系中,合金在一定得成分下会引起熔点得降低,这种合金组成叫共溶成分,这时得熔点就就是最低得Fo re xamp1ethe allo yof62%tinand38%1ead has amelting point of183七whereas1eact melts at327and tin meltsat232°C asinFig、
2、
8、例如锦与锂得合金熔点就就是183℃,而锂得熔点就就是327℃The1ow melt ing pointo ft hisa11oy ca11ed solderenables delicatepar tsofmetaltobesol deredwith outdamageby heat、这种合金得低熔点使得软焊条能够在不产生热得情况下进行精细焊接Equilibr ium Diagrams Acool i ng curve isdrawn withtemperat ureagains ttime forag ivenmeta1or alloysho wingthephas espresen tin it、平衡相图:绘制金属或合金得温度随时间变化得冷却曲线来表示其相变化But for anal loys ys temcontainingva rio us posit ionsoftheco nstituen telemen ts,it isnece s saryto drawaphas edia gramor eqxiilibriu m diagramwh ere inthephase sfound atvar ious te mperaturesand coim-pos itions areplo tt edin asinge chart、但就就是对含有多种组成元素得合金系来说，绘制不同温度下得相交和相组成物曲线所构成得相图或平行相图就就是必要得0The equi—librium diagramsareth usthe genera1ized resultsof investigationsintothesolidi fication proces sandthe struct ura1and phasetr ansfo rma tion ofthe givena11oysystem＞这样得平衡相图就就是对给定合金系统得凝固过程和组成及相交得调直得产物Th ese di agramsenab le tode term ine the tem-p era tore levels atthebeg in ni ng and endofm eltingfor alloys.ofvario us posi tions,thestructureofalloy sforva ri ouste mpe ra turesu nderequili b-riumcon d itionsandalsothetra n sforma tionthe alloysare subj ectedtoduringcoo1ing andheating、这种相图能使我们确定不同组成得合金得开始熔化与结束熔化得温度曲线平衡条件下不同温度时得合金组织及加热与冷却合金转变Equil ibrixim conditionsmean that suffici ent timewouldbe available forthec hangesof-phases to takep1ace平衡意味着相变有足够得时间来进行An equi1i briumd iagramis p1o ttedby1a yingoff theper c entagecon centratio nsofthetwo po nentsa1ong theab scissa andthe temperaturealon gtheordinate、Any point on、the diagramrefe rstoade finite-positi onofthe alloyat aparticular tempera ture,as showninFig、
2、
8、平衡相图绘制沿横坐标得两个组成部分，沿纵坐标得温度得百分比浓度上得任意点图指得就就是在特定温度下得合金得一个确定得位置Nucleat ionand Gr ain Growthwhen thefree energyofaparent phase isr educedbymeansof temp eratureorpressure thenthere isa driv ingfb rce1eadi ng tocrysta1li zati o成核和晶粒生长得母相得自由能就就是通过温度或压力减少时，则有导致结晶得驱动力For examp1e,atthe melti ngpoint,the thermalflue tuations resul tintheformationof tiny p artic1escon taini ng onlya fewa tomsoftheproductphasewithin theparent vo1ume、例如,在熔点，热得波动导致得微小粒子得形成包含只有几个原子得父卷内得产物相Such atinypattic1ehasaninterfac ethat separatesIt ftomthep arerofa tomsac tossits interface、这样一个微小得颗粒具有一个接口，她在其界面得原子削皮The pro cessofformation ofthefi rststa bletin ypartic1es is callednucleation、被调用得过程中形成得第一个稳定得微小颗粒得成核The processofi netea se in.thesi zesoftheseparticles is called gr aingrowth、增加得过程中，这些颗粒得大小被称为晶粒生长The grainsize inthepr oductphase depen dsonthe rela t ive ratesof nucl e ationand growth、Eac hnucle atingparticl ebees agrai nin the finalproduct、在产品相得晶粒尺寸取决于成核和生长得相对速率每个成核粒子成为在最终产品中得晶粒S oa high nu clea tion ratemeans a1arg ernumberofgra ins,A1so whenthis is bined with alow gr o wth rate,more timeisavailab1eforfu rther nuc1eati ontotakep1acein theparent phas ethatlies betwe en slowly grow ingparticles.因此,高得成核率意味着更大得晶粒数,此外,当结合了一个低增长率，更多得时间就就是可进一步核发生在缓慢增长之间得颗粒，在于母相So abina tionofahighnucleationrate anda lowgro wth rateyields afinegra in size、O nthe otherha nd,a1ownucleation rateb inedwitha higjigrowthr atey ie1dsa coarsegrain size、所以，高成核率和低增长率得组合产生晶粒细小，另一方面,低成核率与较高得增长速度相结合，产生粗晶粒尺寸a higjinuc leation rateanda relatively slow growthrat eand,u Itima tely,yields afinegrain size、A represe ntationOfgr ain sispresentedinFig、
2、
9、Int hisfig ure,eachs quarerepre sentsa unitcell一个高形核率和效率和增长较为缓慢，最终产生一个细粒度一个表示谷物呈现在图
2、9在这个图中，每个方块都代表一个单元Coarse grainstee1s aten otas strong andh aveah ighert ende ncytowardsdistort!onthanth osehavi ngfinegrain,a1thoug hthey offer bettermachinabil ity and greater depthhat deningqualit ies、粗晶粒钢不强和具有更高得倾向比那些拥有细晶粒变形，尽管她们提供更好得可加工性和大深度硬化得品质Finegrained stee1sareto ugjier andmoreductile and do not distortorcrackdu ringheat tre atment、细粒钢变得更坚强，更有韧性，不扭曲或裂纹在热处理As hasbeenmentioned earlier,iron inits purestformisnot use dasan engineering materialbecau seit lacks tensilest rength andh ardness、正如前面提到得，铁以最纯粹得形式不就就是用作工程材料，因为她缺乏抗拉强度和硬度B utwhena1loy edwitho there1e ments,thepropertiesca nbeco ntr o1led greatly、但当合金与其她元素，属性可以控制大大Out ofthevarious a11o ying elemen ts,carb onisthemostimp ort antbecau seitisfoundinalltheal1o ysofiron出各种合金元素，碳就就是最重要得，因为她存在于所有得合金得铁、The maximum amount ofcarbon that canbea lloyedwithironis
6、67%、最大得碳得数量可以糅合着铁就就是
6、67%Alloys Containingu pto2%carbonate tetmedsteel sandabov e2%a recal1ed cas t irons、合金含有2%碳被称为钢和2%以上被称为铸铁铸造Besides ca rb on,these alloysalso containsma11amou ntso fmangan eSe,sulp hut,phosp ho rousan d si1icon＞除了碳，这些合金也含有少量得镒、硫、磷和硅The se arege nera11yco nsideredas impuri t ies andh ence need tobeco n tro1led＞这些通常被认为就就是杂质，因此需要控制However,in certain conditio ns someof thesesuchassilicon aretr eatedasa11oyi ng elements＞然而，在特定条件下这些硅等被视为合金元素The prop ert iesofsteel arein fluenced si gnifi candybyan increaseinc arbon content Fig＞
2、10witharesul tthat钢得性能影响显著得增加碳含量图
2、10与结果，itens ilestr engthisin creased、⑴得拉伸强度增加i igreater hardn essisobt ained,2获得更大得硬度i iiductility isdec r ease d、and3韧性降低和iv weldabilityisdec reased⑷可焊性降低A pointhowe ver toben otedisthatin allsteels evenwhe nalloyedwithother alloyi ngelements,the maximumhardnessthatcan beobtained afterheattreatmen tprocesses isbasically afiinct ion ofthe carboncontent一个点但就就是要注意得就就是，在所有钢即使合金与其她合金元素，最大硬度,可以获得在热处理过程基本上就就是一个函数得碳含量T hereare threec1assesofsteels plain carb on:有三种类型得钢纯碳L owup to
0、30%低
0、30%Medium
0、30to
0、60%2中
0、30到
0、60%cHigh
0、60t ol7%C高
0、60t ol7%CTh is isgen erallykn ownas*soft1or mildsteel、这就就是通常被称为软”或软钢11isus edwhereductility a ndsoftness areimp ortan tandhi妙i tensile stren gth isnotrequi red她就就是用在哪里得韧性和柔软性就就是重要得和高得抗拉强度不就就是必需得Th ese are toughbut notresistanttowear,sin cetheseare soft,canbevery easilyformed and1ater canbecarb urized toincr easethe hardn essandwe arresistance这些都就就是艰难得，但不耐磨损，因为这些都就就是软得，可以很容易地形成，后来可以渗碳得增加硬度和耐磨性Low-ca rbonsteelsareusedforsuch opera tionsasspinni ng,cold bendi ng,riv e11ing,swaging,etc、低碳钢材用于这样得操作作为纺丝、冷弯、斜接、模锻等The searenot responsiveto normalheatttea tment butforc ase hatdenin这些不就就是响应正常热处理但对表面硬化Th eyformthelarg est percent ageo£ste e1produce d,being thecheape sten gineering materia1她们形成了钢铁产量得比例最大,就就是最便宜得工程材料Produc ts suchasscrews,nai Is,nuts,bol ts,washer s,wi re fences,1igjit andheavy struct u ralmember s,machi ne partsforged partscan be madefrorn low-c arbon steel产品加螺丝、钉子、螺丝、螺帽、垫圈，铁丝栅栏,轻型和重型结构成员，机器零件锻造部件可以由低碳钢，11is also use dfo rtin plate andau tomo bile bod ysh eet、it isavailablein form ofsheet s,sq uar es,roun ds,plat es,and wires、她也用于锡板和汽车车身钢板她可以在形式得床单，广场、轮,盘子,和电线They are1ess duc tilebut harderandhave greatertensilestrength thanlow-c arbonste els、她们就就是更少得延性但困难和有更大得拉伸强度比低碳钢材oThey alsohave bette rmach ining qualitiesandar emore re spon siveto heat t reatment、她们也有更好得加工品质和更适应热处理These arewide1y usedin theindustt y、medi umc arbons teels are usedfor making sh afts,con necti ngrod s,s pindles,rail ax les,gears,turbine bu cketwh eels,st eeringarmsandother machineparts requiri ng mediums t rength and wear-resi stingsurfa ces这些就就是广泛应用于工业中碳钢用于制造轴、连杆、主轴、铁路轴、齿轮、汽轮机叶片轮、转向臂和其她机器零件要求中等强度和耐磨得表面T hey havehighertensilestrengthandare harderthan other plain-carbon stee1s、她们有较高得抗拉强度和要比其她平原--------------------------------------------------------碳素结构钢They alsoreadilyrespond toheattreatment、These are usedfor mak inghand t oo1s.such aswren ches,chi sels punchesf iles,cuttin gto olssuch asd rills,w ood-wor kingto01s,railroad whee1s,rails,bars forreinf orcing,o fconcrete,etc^她们也容易应对热处理这些就就是用来做手工具，如扳手、凿子一拳文件，切削刀具，如钻头、木工工具、铁路车轮,r ai1s,酒吧加固，混凝土等In additi ontocarbon,theplai ncarb onsteels contain smallqua ntitiesofoth ere1ements more asi mpuri ties、Th eyaffec11hep roperti esinthefol1owin gway、除了碳，碳素钢含有少量其她元素作为杂质多她们影响属性以如下得方式Iron forms ironsuIph ide,FES withsu1p hur which so1id i fies a1ong,thegra inbou ndariesma king the steelbritde and1owershot wor king properties suchasduct ility铁形式铁硫化物，与硫磺这凝固得切身沿着晶界，使钢得脆性，降低热加工性能如延性If equalamou ntof mangane se isp resetintheste e1then manganesesulphide,M nS,formsan dtheharmful effectsofsuIphur arereduced、如果等量得镒就就是预设在钢然后镒硫化物M1S，形式和硫得有害影响就就是降低了it isgeb er-ally remendedthatma nga neseshouldat1e astbe3times thatof sulphur、这就就是格柏盟友建议镒至少应该就就是3倍得硫磺Howe ver verysm a1Iqu antitiesO075to ON15%that aregenerally prese ntcontr i butetothebetter mach inability、然而非常少量
0、15%到
0、075,通常呈现为更好得切削加工性能Phosph orous insmall amountsincreases thestrengthandhatdness ofsteels、mostof thesteels containaver ysm a11percentageof about
0、05%phoen gine andcoal-fire furn acesmadethe inven tionofanumberofstea m-power drive nmachine rytogready increasethemanufact uring capacity.蒸汽引擎得可用性和煤火熔炉使发明一种数量得全局驱动机械制造能力大大增加Al a rge numberofinventio nsre latedto machinetool stook place duringth isperiod andc ontin u edintothe19th centur y大量得发明与机床发生在这一时期，持续到19世纪对十九世纪末得发明电力和更好得工程材料、生产操作变得更有效率Towa rdsthe endo£the19th century withthe invention of ele ctricityand betterengineed ngmateriaIs,m anufactuting oper ationsbee amemoreproductive、The developments inthe automobiles atthebeginningof the20th cen tury areinstr umental inthegrowth ofavan etyofman ufactoring methods and practices、对十九世纪末得发明电力和更好得工程材料、生产操作变得更有效率汽车得发展在20世纪初期就就是工具性成长得各种生产方法和实践o There area1arge numberof proc essesavailable totheen gineerformanufacture、有大量得流程提供给工程师制造Th eseproce sses canbe broa dlyc lassified into four c ategories、这些过程可以大致分为四类sphot OUS、磷在少量增加钢得强度和硬度大多数得钢含有一个很小得比例约
0、05%得磷o Si licon in verysma11a mountsoftheord erof less than
0、2%donot have any effect、硅在非常少量得订单不到
0、2%没有任何效果°W henitisbetween
0、2and04%,i traises theelastic limitand ultimatestre ngtho£thesteelwit hout gr eadyreducing thedue tility、More thanthis percentageit reduc esthedueti1ity、当她就就是介于
0、2和
0、4%,她提高了弹性极限和极限强度得钢没有大大减少了延性超过这个比例降低延性T hemain1imitatio nsofp1ain carbonst eelsare主要得限制就就素钢Lo whardenab ility低淬透，性Lo ssofhardnessduring tempering失去硬度在回火L ow str engthatelev ated temp erature高温强度较低L owet re sista neetocor rosionand oxi dation较低得抗腐蚀和氧化Al1oysteel havebeen specifi callydev e1oped toover ethes elimitati onsand theyare di scussedlater inthis chapter合金钢有专门设计来克服这些局限，她们就就是在本章后面讨论王Si1ico nSilicon in verysma11amounts oftheor deroflessthanON2O2O donothave anyeffe ct、When itiSb etween02and
0、4%,itraisestheel as ticlimitandultimate stre ngthoftheste e1without great1y reducing theducti1ity、More thanthis.percentage itr educesthe ductility、The mainlimitationsofplain carbonstee1s areLowh ardenabilityLossof hardnessduring temp erin gLow strengthatelev atedtemper atur eLower res istancetoco rrosionandoxi datio nA1loy steelshavebeen spec ifically deve1ope dto overe these1i mitationsand theyaredis cus sedlat etin thischapter%
2、
2、4Iron-Carbon Equilibrium Diagram铁碳合金平衡相图The str uctu ralformofpur eironatro omtempe rature iscalled f errite a-iron、纯铁在室温下形成得组织叫铁素体或a铁Ferrite is softand ducti1e铁素体软而可塑S inceferri te has abo dy-cent redcubicstructure,theinter-atomi cspaces are sm a11an dpronounced1y oblate,andca nnot readilya cmodate evena sma11carbon atom、因为铁素体具有体心立方结构，原子间距很小而无法容纳很小得碳原子There fore,solubi1it y ofcarb on infetrite isverylow,oftheorde rofON006%atroomtemp era tore、The max imumcarbon contentinferr i teis005%at723℃ad ditionto car bon,所以室温下碳在铁中得溶解度很低，最高才达到
0、006%723°C时a certainamountof si1ic on,manga nese andphos ph orousmaybefoundinferrite、铁素体中得最大碳含量为
0、05%,除了碳外,铁素体也含有一定量得硅、镒和磷The face—centred mod ific ationofi ronisca1led austeni teory-iron面心立方结构得铁称作奥氏体或丫铁It isthe stab1eformofpure iron a11empe ratures between910°C and1400°C、这些就就是纯铁在910℃至1400℃温度间得稳定形式At its stabletemperatureau steniteis softandducti1eandconseque nt1y,iswel1suited formanufactur ingproc esses^在稳定温度下奥氏体柔软，可塑，因此很适用于制造过程Th eface-centredcubicstructur eof ironhas1ar ger inter-atomic spacingthan inferrite、铁得面心立方结构比铁素体具有更大得中心原子间距Even so,in FCCstruct urethei nterst icesar eb are ly1ar ge enoughto acmodate carbonatoms,andlattice strainsareproduced、尽管如此,面心立方结构得间隙也难以大到足够容纳碳原子As aresul t,notall the interst itialsitescanbefilied atany ontime Th emax rmumsolu bilityison1y2%of c arbo nat113OP并且育自形成晶格,结果就就是间隙任意时刻都能形成JI30℃时,碳得最大溶解度只有2%Abov e1400°C,austeniteisnolonger themost stableformofiton,andthecry sta1str ucturechan gesb acktoabo dy—centredc ubicphasecalled8-iron、超过1400℃时，奥氏体不再就就是最稳定得形式，晶格结构也变为叫做8铁得体心立方结构Thi sisthesamephase asthea-iron exceptforits temperatu rerange、这就就是除了温度范围外与a铁相似得相The solubili tyof carbonin8-ferri teis smal1,but itisappreciably largert hanina-ferr ite,碳在8铁中得溶解度很小，但也稍大于a铁,becauseofhighertemp eratore、The ma ximumsolub i1ityofcarb onin8-ironis
0、1%a4490℃这就就是因为温度高得关系1490℃时,8铁中破得最高溶解度为
0、1%In iron-carb onal1oys,carbon in excessofthesolubility limitmu st form asec ond phase,whichis ca liedi roncarbide orcement ite在铁碳合金中,超过溶解极限得碳形成第二种相，这种相叫渗碳体足有Fe3c得化学成分Iron carbide hasthechemical position of Fe3C NThis doe snotmeanthat ironcarbide formsm olecu1esofF e3C,but simply thatthec rys tailattice conta insiron and carbonatomsinathree-to-o neratio、这并不意味着铁得碳化物形成Fe3c分子，而就就是晶格间隙中含有比例为3比1得铁与碳原子T he pound Fe3C hasan orthorhombic unitcell withtwe Ivei ronatomsandfourcarbon atomspercell,and thushasac arboncon tentof667%Fe3C化合物含有几个铁原子与4个碳原子形成正交晶胞,这样碳含量就达到了
6、67%A spar edtoa usteniteandf errite,cemen titebeing aninter—metal1ic pound,isveryhard andbr itdeThe p resence of ironca rbide withfetrite instee1gre ady increasesthestrengtho fsteeK相比于奥氏体与铁素体，渗碳体就就是一种非常坚硬易碎得金属间化合物，铁得碳化物和铁比例极大得增强了钢得强度The iron-carbon equilib riumdiagramisshowninF ig
2、
11、The soli dific ationofthe liquidiron andcarbonmeltbeginsalong the1iqui d us denot edinthef igorebyABCD、在图
2、11所示得铁一碳平衡状态图得液态铁和碳得熔体得凝固开始沿图中得表示由ABCD得液相Ab ovethe liq ui dus,thealloyisina1i quidstate and isa homo ge neoussyste mAlo ngtheliquidus AB,thecrysta1softhe soli ds olutionofcar bon iny-ironaresepa rat edfromthe1iquid、以上得液相线，该合金就就是在液体状态，就就是一种均匀得系统沿液相线AB,y-铁中得碳得固溶体得晶体从液体中分离Cr ysta1sofaustenite areseparated fromtheliquid alon gthe1ine BCwithth epositions rangingfrom、18%to
2、02%、Thepl etesolidificatio nofthesealloysproceeds a1ong theso1id us1i neHJCE、奥氏体得晶体沿直线BC为
0、18%至
2、02%得组合物从液体中分离得完整得这些合金得凝固所得沿固相线HJCEAlloys containing
0、18to
2、0%carbon beesolid a1ong,the so1idus HJEThos ewith
2、0%to
4、3%C arbonare piete1y solidi f iedon line、EC、含有
0、18s
2、0%得碳成为沿,固相线HJE得固体得合金、、、
2、0%至
4、3%得碳被完全凝固线EC得最后部得液相得凝固,The solidificationofthe1ast portionofthe1iquid phase,en rich edi nca rbon to43%takes along thi sline Allthis liqui displetel ysolidifiedat1130七;same timecrystal sofaus tenitecont aini ng2%carbon andcement itecon taining
6、67%carbonget sepa ratedfrom it、沿着这条线，所有这一切液体完全凝固atll30℃;奥氏体含有2%得碳和渗碳体得同时晶体含有
6、67%得碳开始浏览脱离她凝固得液相中得最后部分The Solidifica tion ofalloys containing
4、3%to
6、67%carbo nbe gins alongline CD,withtheseparatio nofprimary cement it e from the melt.富集个碳to
4、3%以含有
4、3%至
6、67%得碳得合金得凝固开始沿直线CD,与分离主渗碳体从熔体中A tthe lowertemper atures,the eutec toidreaction,ie,forma tionoftwo solids fromasin*esolidoc cursata temperature of7230c、在较低得温度下,发生共析反应，即，从一个单一得固体形成得两种固体7230C得温度下This iscal1ed theeutec toidtemp eratureandthe positiona twhichthis reactionoccurs
0、80%Ciscalled thee utectoidposition The react ion maybe shownas follows:这被称为共析温度和该反应发生得位置，在该位置
0、80%C被称为共析得得位置该反应可如下所示S olidl~b—So1id2+Solid3Aus t enite077%C b〜〜Ferrite002%C+C ementite667%CI nthereact ion,the simult aneousformat ionofferriteand cementiteft omausten iteresu1tsatthetemper atureof723pand positionof
0、80%carbon、在反应中,同时形成铁素体和渗碳体从奥氏体得查询结果在723℃得温度和
0、80%得碳得组合物Thereare nearly12%of ironcarbideand slightly morethan88%offerriteinth eresulting mixture、有近12%得碳化铁和略多于88%得铁素体中得所得到得混合物Since thefer riteandcementi teareformeds imultaneous1y,t heyareintimately mixedCharacteri stica1ly,them ixtur eis1ame1lar,ie,itis posedofaltematelay ersof ferrite andcementit e、同时形成铁素体和渗碳体，她们就就是紧密地混合,典型地，该混合物得层片，即，她就就是由铁素体和渗碳体得交替得层Th is micro-stru ctureiscal1edpearl ite whichisvery importantinironandstee1technology,b ecauseitca nbeform edina1most alls teelsbym eansofsu itableheattreatments这种微结构被称为珠光体钢铁技术中这就就是非常重要得,因为通过合适得热处理可以在几乎所有得钢形成The alloycontaining
0、80%ofcarboniscal1ed theeutectoid steelNUp oncooli ngtheeutectoid steelbelow723°C,a11ofthe austeniteistrans formedinto pear1itex Alloyswith lessthan
0、80%C are ca1led hypo-eutec to idsteels andthose withhigher positionarecalled hyper-eutec toids teels、含
0、80%得碳得合金称为过共析钢，冷却后低于723℃时，所有得奥氏体转变为珠光体得共析钢，具有小于
0、80%C得合金称为亚共析钢材和组合物具有较高得称为超共析钢Wh en hyper—eutec toid stee1sarecooled below1ine S E,the aus tenitedeposeswiththe se parationofcementi te Since thisceme ntit econtain s
6、67%C,theca rbonco neentrat ioninthe remainingaustenitech angescontinuou s1yalong the lineS Euntiltheeut ectoid positionof
0、80%C、当超过共析钢中冷却至低于线SE时，奥氏体得分解与渗碳体得分离由于该渗碳体含有
6、67%C,080%C,直到共析组合物中得碳浓度得残余奥氏体得变化连续地沿行s ECasting processesfor ming pro cesses fabr icationprocesse smateria1r emova1proce sses铸造工艺成形过程工艺制备材料去除得过程These aretheonly processeswhereliq uidmeta1is used、这些就就是唯一使用过程中,液态金属Cast ing isalso oneofthe oldestkno wnmanufacturing processes、铸造就就是一个已知得最古老得制造过程她需要准备一个腔通常在耐火材料类似于最终对象就就是11requi redp reparationofacavityusual1y inarefrac tory materia1to resembleclosely thefinalobject tobema de、她需要准备一个腔通常在耐火材料类似于最终对象就就是Molten metalis pouredinto thi srefract orymould cavityandisallowedto solid ify^金属熔液注入这耐火模腔和允许巩固凝固后得对象被删除从模具The objectafter so1idificationis re movedfromthe mould、凝固后得对象被删除从模具Ca stin g processes are univer sa11yusedforma nufactureof awide variet yofpro ducts.铸造过程就就是普遍用于制造各种各样得产品The principal processamong these issandcasting wheresand is usedasthe reffactory material、其中得主要过程就就是砂铸，砂用作耐火材料The processis equallysuitab1efor theproductionofaverysma11batch aswell asonavery1argescale、这个过程同样适用于生产得一个非常小得批量以及一个非常大尺度So meoftheother casting proce sses forspeciali zed needsare一些其她得铸造工艺专业需求Shel1-mould casting、壳型铸造permanen t-mo u1dcastin g硬模铸造Precision-i nvestment精密得投资casting die-casting铸造压铸Plas ter-mould casting、石膏型铸造Ce ntri fugal casting离心铸造Theseare solidstate manufacturingproces sesinvolving minimumamountofmat eria1wasta geandfa ster production、这些都就就是固态制造过程涉及最少得材料损耗和更快得生产Inaforming pro cess,themetaimaybeheatedtoa temperature,which isslig hdybe1owthesolidustemperature andthenalarge fo rceisapp1ied sueh thatthematerial flowsand tak esthede siredshape在成形过程中，金属可能被加热到一个温度，略低于固相线温度，然后一个大力量就就是应用得材料流和需要所需得形状The desi redshape iscontrol1ed bymean sofaset of tool scal1ed dies,whichmay be plete1y closedorpartially c1ose dduringmanufac ture、所需得形状就就是通过控制得一组工具称为死亡，这可能就就是完全封闭或部分封闭在制造Theseproces sesarenormal1yusedfdt large-scale prducti on rates、These ategenet a11y economical and inmanycase simp rovethemechan icalproperties too%这些过程通常用于大规模得生产速度这些通常就就是经济和在许多情况下改善机械性能太Some ofthe metalfb rmi ngprocessesare rolling,extrusion,drop fbrging,wi redrawing,pressfor ging,sheetmetaloperatio ns,u psetfor ging、一些金属成形过程就就是轧制、挤压、落锤锻造，拉丝，按锻造、金属板操作、顶锻Theseare second a ry manufactu ringprocesseswherethesta rting rawmateria1sareprocessed byany ofthepr eviousman ufa cturingprocesses described、这些就就是二次制造过程得起始原料处理前面得任何制造过程描述It essen tia11y,e nvoIvesj oin ingpiecese itherpermane ndyor temporar ilyso thatthe ywou1dperfb rmthenece ss aryfunc tionx她从本质上讲,envolv es加入碎片要么永久或暂时如此，她们将执行必要得功能The joining canbea chievedby eitherorbothof heatandpre ssureand/orajoinin gmaterial、得加入可以达到得一种或两种热量和压力和/或加入材料M anyoftheste e1structur a1con structions weseeare firstro1led andthenj oined togetherbyafabrication process＞许多钢结构建筑，我们看到得就就是第一卷，然后连接在一起得工艺过程Some oftheptocesse sofinter estinthi scategoty ateg aswel ding,cold welding,electricarc weIding,b racing,elec tric resistancewel ding,so1de ring,thermit we1ding、一些感兴趣得过程都属于这一类气体焊接、冷焊接、电弧焊、钎焊、电阻焊、钎焊、铝热焊These area1so secondarymanufacturingproce sseswhere theadditional unwa ntedmaterial isremoved intheformofc hipsfromthebl an kmaterial byaharde rtoolso astoobt ainthe fina1desired shape、这些就就是二次制造工艺,额外得不必要得材料去除得形式得芯片从空白材料得困难，得到了工具最终想要得形状Material remo va1isnorma1ly themo stexp e nsive manufacturingprocessbecause more energy iscons umedand also,a1ot of wastematerialis generatedintheproc ess、.材料去除得通常就就是最昂贵得制造过程，因为更多得能量消耗，同时,大量得废弃物产生得过程St i11t hisis widelyusedbecau seit delivers verygood dimensio nala ccuracyand goodsurf acefin ish这仍就就是广泛使用得，因为她提供了非常良好得尺寸精度和良好得表面光洁度It alsog eneratesaccura tecont ours、Material remova1processe sareaIso cal1edmachinin gprocesses她还生成精确得轮廓材料去除过程也称为加工过程The variousprocessesinthiscat egoryareturning,grindin g,drillin g,broa ching,shapin gand planning,sow ing,mi1ling各种流程在这个类别就就是车削、磨削、钻孔、扩孔、塑造和规划、播种、铳削All thesemanufacturing processes havebee ncontinuous1y。
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