材料成型及控制工程專業(yè)英語(yǔ)11.casting

1、材料成型及控制工程專業(yè)英語(yǔ)Translation Skill Semantic Extension （翻譯技巧 句子成分轉(zhuǎn)換）謂語(yǔ)、表語(yǔ)、賓語(yǔ)、狀語(yǔ)轉(zhuǎn)譯成主語(yǔ)；主語(yǔ)、定語(yǔ)、表語(yǔ)、狀語(yǔ)轉(zhuǎn)譯成謂語(yǔ)；主語(yǔ)、狀語(yǔ)、賓語(yǔ)轉(zhuǎn)譯成定語(yǔ)；定語(yǔ)、謂語(yǔ)、主語(yǔ)轉(zhuǎn)譯成狀語(yǔ)；主語(yǔ)、狀語(yǔ)、謂語(yǔ)轉(zhuǎn)譯成賓語(yǔ)；主語(yǔ)、賓語(yǔ)轉(zhuǎn)譯成表語(yǔ)。 句子成分轉(zhuǎn)換是指詞類不變而成分改變的譯法。通過(guò)改變?cè)闹心承┚渥映煞?，以達(dá)到譯文邏輯正確、通順流暢、重點(diǎn)突出等目的。謂語(yǔ)、表語(yǔ)、賓語(yǔ)、狀語(yǔ)轉(zhuǎn)譯成主語(yǔ)Gases differ from liquids in that the former have greater compressibility t

2、han the latter.譯：氣體和固體的區(qū)別，在于前者比后者有更大的壓縮性。（謂語(yǔ)轉(zhuǎn)譯成主語(yǔ)）Rubber is a better dielectric but a poorer insulator than air.譯：橡膠的介電性比空氣好，但絕緣性比空氣差。（表語(yǔ)轉(zhuǎn)譯成主語(yǔ)）Water has a density of 62.4 pounds per cubic foot.譯：水的密度是每立方英尺62.4磅。（賓語(yǔ)轉(zhuǎn)譯成主語(yǔ)） Aluminum is very light in weight, being only one third as heavy as iron.譯：鋁的重量很

3、輕，只有鐵的1/3.（狀語(yǔ)轉(zhuǎn)譯成主語(yǔ)） The same signs and symbols of mathematics are used throughout the world.譯：全世界都使用同樣的數(shù)學(xué)記號(hào)和符號(hào)。（狀語(yǔ)轉(zhuǎn)譯成主語(yǔ)）謂語(yǔ)、表語(yǔ)、賓語(yǔ)、狀語(yǔ)轉(zhuǎn)譯成主語(yǔ)主語(yǔ)、定語(yǔ)、表語(yǔ)、狀語(yǔ)轉(zhuǎn)譯成謂語(yǔ)The prevention of many types of occupational diseases isdistinctly within the realm of possibility.譯：許多職業(yè)病顯然可以預(yù)防。（主語(yǔ)轉(zhuǎn)譯成謂語(yǔ)）A semiconductor has a poor

4、 conductivity at room temperature, but it may become a good conductor at high temperature.譯：在室溫下，半導(dǎo)體導(dǎo)電率差，但在高溫下，它可能成為良導(dǎo)體。（定語(yǔ)轉(zhuǎn)譯成謂語(yǔ)） The wide applications of computers affect tremendously the development of science and technology.譯：計(jì)算機(jī)的廣泛應(yīng)用，對(duì)科學(xué)技術(shù)的影響極大。（狀語(yǔ)轉(zhuǎn)譯成謂語(yǔ)）Also present in solids are numbers of free

5、 electrons.譯：固體中也存在著大量的自由電子。（表語(yǔ)轉(zhuǎn)譯成謂語(yǔ)）主語(yǔ)、定語(yǔ)、表語(yǔ)、狀語(yǔ)轉(zhuǎn)譯成謂語(yǔ)主語(yǔ)、狀語(yǔ)、賓語(yǔ)轉(zhuǎn)譯成定語(yǔ)CMOS chips in the computer work a thousand times more rapidly than nerve cells in the human brain.譯：電腦芯片的工作比人類大腦中的神經(jīng)細(xì)胞要快1000倍。（主語(yǔ)轉(zhuǎn)譯成定語(yǔ)） In Britain the first stand-by gas-turbine electricity generator was in operation in Manchester in

6、1952.譯：英國(guó)的第一臺(tái)輔助燃?xì)獍l(fā)電機(jī)于1952年在曼徹斯特開(kāi)始運(yùn)轉(zhuǎn)。（狀語(yǔ)轉(zhuǎn)譯成定語(yǔ)） By 1914 Einstein had gained world fame.譯：1914年愛(ài)因斯坦已成了著名的科學(xué)家。（賓語(yǔ)轉(zhuǎn)譯成定語(yǔ)）定語(yǔ)、謂語(yǔ)、主語(yǔ)轉(zhuǎn)譯成狀語(yǔ)After more experiments, Galileo succeeded in making a much better telescope.譯：又做了一些實(shí)驗(yàn)之后，伽利略成功地制造了一架好得多的望遠(yuǎn)鏡。（謂語(yǔ)轉(zhuǎn)譯成狀語(yǔ)） The result of its revolutionary design is that the engi

7、ne is much smaller, works more smoothly, and has fewer moving parts.譯：由于他在設(shè)計(jì)上的革新，發(fā)動(dòng)機(jī)變得小多了，工作得更平穩(wěn)了，活動(dòng)部件也少了。（主語(yǔ)轉(zhuǎn)譯成狀語(yǔ)）It was an amazing piece of scientific clairvoyance, comparable perhaps to Charles Babbages anticipation of the principle of the computer.譯：這個(gè)理論在科學(xué)上充滿了元件卓識(shí)，也許可以跟巴貝奇的計(jì)算機(jī)原理相提并論。（定語(yǔ)轉(zhuǎn)譯成狀語(yǔ)）定語(yǔ)

8、、謂語(yǔ)、主語(yǔ)轉(zhuǎn)譯成狀語(yǔ)主語(yǔ)、狀語(yǔ)、謂語(yǔ)轉(zhuǎn)譯成賓語(yǔ)The mechanical energy can be changed back into electrical energy by means of a generator.譯：利用發(fā)電機(jī)可以把機(jī)械能重新轉(zhuǎn)變成電能。（主語(yǔ)轉(zhuǎn)譯成賓語(yǔ)）Television has been successfully sent by laser, too.譯：用激光發(fā)射電視也獲得了成功。（狀語(yǔ)轉(zhuǎn)譯成賓語(yǔ)） The sun affects tremendously both the mind and body of a man. 譯：太陽(yáng)對(duì)人的身體和精神都有極大的

9、影響。（謂語(yǔ)轉(zhuǎn)譯成賓語(yǔ)）主語(yǔ)、賓語(yǔ)轉(zhuǎn)譯成表語(yǔ)A great contribution of Edison was the carbon microphone.譯：炭精傳聲器是愛(ài)迪生的一大貢獻(xiàn)。（主語(yǔ)轉(zhuǎn)譯成表語(yǔ)） The production had considerable difficulty getting patent protection if it had no patent right.譯：如果產(chǎn)品沒(méi)有專利權(quán)，要獲得專利保護(hù)是相當(dāng)困難的。（賓語(yǔ)轉(zhuǎn)譯成表語(yǔ)） 由此看來(lái)，句子成分的轉(zhuǎn)譯顯得變化萬(wàn)千，異彩紛呈，難于窮究，幾乎所有的句子成分都可以互相轉(zhuǎn)譯。進(jìn)行成分轉(zhuǎn)譯的目的是為了使譯文通順

10、，合乎漢語(yǔ)習(xí)慣和更好地跟上下文響應(yīng)。CHAPTER 11 CASTING11.1Various Casting Processsand mold 砂型plastic-bonded shell mold 塑性粘結(jié)殼型die-casting metal mold 壓鑄用金屬型plaster mold 石膏型investment 熔模鑄造shrinkage 收縮flask 砂箱core 型芯dry sand molds 干砂鑄型- 12 -CHAPTER 11 CASTING11.1Various Casting Processgreen sand mold 濕砂鑄型thermosetting re

11、sin 熱固樹(shù)膠（脂）centrifugal casting 離心鑄造low-melting alloys 低熔點(diǎn)合金silica 硅石，硅土，無(wú)水硅酸ethyl silicate 硅酸乙酯tilting furnace 可傾式鐵爐- 13 -砂型和芯是用型砂和芯砂制造的。型(芯)砂是由原砂、粘結(jié)劑、水和附加物按一定比例混合制成。用一種遇熱硬化的型砂（酚醛樹(shù)脂覆膜砂）覆蓋在加熱到180280的金屬模板上，使其硬化為薄殼（薄殼厚度一般為612毫米），再加溫固化薄殼，使達(dá)到足夠的強(qiáng)度和剛度，因此將上下兩片型殼用夾具卡緊或用樹(shù)脂粘牢后，不用砂箱即可構(gòu)成鑄型，澆注鑄件金屬模板的加熱溫度一般為300左右

12、，使用的型砂為樹(shù)脂砂，即以酚醛樹(shù)脂為粘結(jié)劑的樹(shù)脂砂。同樣也可用上述方法將型芯制成薄殼芯制造薄殼鑄型常用翻斗法。制造薄殼芯常用吹制法。- 17 -CHAPTER 11 CASTING The principal casting processes are classified according to the kind of mold used. These are sand molds, plastic-bonded shell molds, permanent and semipermanent metal molds, die-casting metal molds, plaster mo

13、lds, and investment molds.主要的鑄造工藝是根據(jù)使用的模具種類來(lái)分類的。模具類型是砂型，塑性粘結(jié)殼型，永久和半永久性的金屬型，壓鑄金屬模型，石膏模具，熔模鑄型。 classify 分類；分等permanent 永久的砂型鑄造視頻- 18 -CHAPTER 11 CASTING The first step in the production of a sand casting is to make a metal or wooden pattern.The pattern is a replica of the part being made but has sligh

14、tly larger dimensions to allow for shrinkage during solidification and cooling of the casting. 砂型鑄造生產(chǎn)的第一步是制造一副金屬或木質(zhì)模型。該模型是所鑄零件的復(fù)制品，但是考慮到鑄件凝固和冷卻過(guò)程中產(chǎn)生收縮，這個(gè)模型尺寸有些許放大。 replica 復(fù)制品，復(fù)制物shrinkage 收縮- 19 -CHAPTER 11 CASTINGThe pattern is often made in two or more parts so it can be removed easily from the m

15、old. To make the mold, sand is rammed or packed around the pattern, the sand being held in place by a boxlike container known as a flask. 木模往往被做成兩部分或更多部分，所以他們能夠很容易地從模具中（這個(gè)模具其實(shí)就是沙子制成的）取出。為做出這個(gè)模具，砂子在木模周圍要壓緊、夯實(shí)，砂子被放在稱為鑄型砂箱的盒子形狀的容器內(nèi)。ram 壓實(shí)、夯實(shí) packed 充滿的，塞滿了的boxlike 箱型的 flask 砂箱、鑄型砂箱 - 20 -CHAPTER 11 CAS

16、TINGAfter the flask is filled with sand, the pattern is withdrawn, leaving a mold cavity similar to the finished casting.當(dāng)砂箱充滿砂子后，木模被抽回，剩下具有與成型鑄件一模一樣的模具型腔。 withdraw 取出；撤退- 21 -CHAPTER 11 CASTINGIf there are hollow spaces in the casting, such as an axle hole in a wheel, sand molded to the shape of th

17、e hollow space must be placed in the mold cavity. These void-producing shapes are known as cores. 如果鑄件有中空部分，例如輪零件的中間軸孔，在這種模具型腔中，需要放置被制成中空形狀的型砂。那些能形成中空形狀的型砂被稱為型芯。hollow 中空的、空心的 axle hole 軸孔 void-producing 產(chǎn)生空隙 core 型芯- 22 -CHAPTER 11 CASTINGThe sand used for the mold and cores is held together by cla

18、y and cereal-bonding agents. If the molds are baked, they are known as dry sand molds. If used in the moist condition, they are known as green sand molds. 用于模型和型芯的砂子是用粘土和谷物粘結(jié)劑粘結(jié)在一起的。如果模型進(jìn)行烘干，他們就被稱作干砂鑄造。如果在潮濕的條件下使用，他們就被稱作濕砂鑄造。clay 粘土、白土、泥土 cereal-bonding agents谷物類粘結(jié)劑 baked 烤 moist 潮濕- 23 -CHAPTER 11

19、CASTINGDry sand molds are stronger than green sand molds and show greater resistance to erosion and crushing. Surface quality of sand castings is improved by covering the pattern with a fine sand known as facing sand before ramming the balance of the sand.干砂模型比濕砂模型要堅(jiān)固，而且表現(xiàn)出較強(qiáng)的耐侵蝕和抗壓碎能力。在對(duì)砂子進(jìn)行均勻緊實(shí)之前，

20、通過(guò)對(duì)砂型表面覆蓋被稱為面砂的細(xì)砂，能使砂型鑄件的表面質(zhì)量得到了提高。crushing 壓碎、破碎- 24 -CHAPTER 11 CASTINGPlastic-bonded shell molding is a modification of sand casting. A metal pattern is heated to about 350F( 175 C ) and then clamped on top of a box containing a mixture of fine sand and a thermosetting resin.塑性粘結(jié)殼型鑄造是砂型鑄造的改良。先把金屬

21、模型加熱到175度，然后固定在裝滿細(xì)砂和熱固樹(shù)脂的盒子的頂部。 clamp 夾緊、夾持、卡緊 thermosetting resin 熱固塑膠（脂）殼型鑄造視頻- 25 -CHAPTER 11 CASTING When the box is inverted and its contents fall on the hot pattern, the resin is softened by heat. This causes a thin shell of molding material to form around the pattern. 當(dāng)盒子倒置過(guò)來(lái)時(shí)，盒子里的砂子會(huì)落在熱的模型上，

22、樹(shù)脂就會(huì)被熱軟化。這樣就在模型周圍形成了一個(gè)薄薄的模具的殼。invert 倒置- 26 -CHAPTER 11 CASTINGThe box is then returned to its original position, and the unreacted resin and sand fall away from the pattern. After the resin has had time to harden fully the shell is stripped. 然后盒子返回原位，沒(méi)有起作用的樹(shù)脂和砂子就會(huì)落下離開(kāi)模型。當(dāng)樹(shù)脂經(jīng)過(guò)一定的時(shí)間重復(fù)硬化后，這層殼就被剝離。unre

23、acted 沒(méi)有起反應(yīng)、沒(méi)有起作用resin 樹(shù)脂- 27 -CHAPTER 11 CASTINGA finished mold consists of two matching shells held firmly together and surrounded by metal shot (or some other backing material) that is kept in place by a flask. Use of metal shot increases the speed of cooling and solidification.一副完成的模具包含兩個(gè)緊緊地固定在一

24、起的匹配的殼，并環(huán)繞著模具包裹著的鐵丸（或者一些其他的基底材料），運(yùn)用金屬噴丸會(huì)提高冷卻和固化的時(shí)間。- 28 -CHAPTER 11 CASTINGPermanent and semipermanent molds are made of metal. Permanent molds use metal cores if coring is required. Semipermanent molds use sand cores. The halves of the mold are frequently hinged and fastened with a screw device. 永久

25、或半永久型模具由金屬制成。如果需要型芯永，那么久性模具使用金屬芯。半永久性模具運(yùn)用的是砂芯。兩半模具頻繁地被鉸鏈在一起并被螺旋裝置固定。hinged 鉸鏈、用鉸鏈（結(jié)合、附著）fastened 扣緊、固定、關(guān)牢 screw 螺旋（絲、孔、釘）- 29 -CHAPTER 11 CASTINGMold coatings or washes consisting of a refractory material, a lubricant such as graphite or rouge, and a binder, are used to assist removal of the casting

26、 from the mold. Different mold materials are used depending upon the metal being cast. 模具涂料或薄涂漿中包含有耐火材料，石墨或過(guò)氧化鐵粉的潤(rùn)滑劑，粘結(jié)劑，涂料用來(lái)幫助從模具中取出鑄件。模具材料的運(yùn)用依賴于鑄造的金屬不同。washes 涂漿、洗滌劑 refractory 耐火的lubricant 潤(rùn)滑劑；潤(rùn)滑油 graphite 石墨rouge 紅鐵粉，三氧化二鐵 binder 粘結(jié)劑- 30 -CHAPTER 11 CASTINGCentrifugal casting is a special form o

27、f permanent mold casting, using a rotating mold that throws the metal outward against the mold walls. It is used for castings that have a rotational axis of symmetry, such as pipe, gun tubes, and gear stock.離心鑄造是永久性模具鑄造的特殊形式，它運(yùn)用旋轉(zhuǎn)的模具把金屬向外正對(duì)著拋向模具四壁。常用于具有對(duì)稱性旋轉(zhuǎn)軸的鑄件，像管狀鑄件、炮管、齒輪裝置。centrifugal casting 離心鑄

28、造 gear stock 齒輪裝置離心鑄造視頻- 31 -CHAPTER 11 CASTINGDie casting is an improved version of permanent mold casting. The essential features of a die-casting die are shown in Fig. 11.1. In die casting, the molten metal is forced into the mold or die under pressure. 壓鑄是永久型金屬模鑄造的改進(jìn)的形式。圖11.1表示了壓鑄模的基本特征。在壓鑄模鑄造中，

29、熔融的金屬在壓力的作用下進(jìn)入型腔。version 版本- 32 -CHAPTER 11 CASTINGHalf of the die is rigidly attached to the frame of the die-casting machine, and the other half is movable. Design of the die is such that the casting tends to adhere to the movable portion of the die.一半模具被剛性地固定在壓鑄機(jī)的框架上，另一半模具能夠運(yùn)動(dòng)的。模具如此設(shè)計(jì)，能使鑄件依附于模具的動(dòng)

30、模部分。rigidly 剛性地 frame 框架；結(jié)構(gòu)adhere 依附；粘著 portion 部分- 33 -CHAPTER 11 CASTINGAs the mold opens, the casting is carried with the movable portion of the die until knocked clear by the ejector pins shown in Fig. 11.1. Dies are oil-or-water-cooled to permit more-rapid operation. 隨著模具的打開(kāi)，鑄件跟隨動(dòng)模部分運(yùn)動(dòng)直到由推桿把鑄件完

31、全推離模具，如圖11.1。為了快速生產(chǎn)，模具用水路或者油路冷卻。knock 敲；打 clear 完全地ejector pins 頂桿 ；推桿- 34 -CHAPTER 11 CASTINGWhen hot metal enters the mold, it forces the air from the die cavity through shallow grooves ground in the die faces. Some die-casting machines are also fitted with vacuum devices that evacuate the die cav

32、ity before the hot metal is charged into it. 當(dāng)熱的金屬液進(jìn)入模具，金屬液就會(huì)把模具型腔內(nèi)的氣體通過(guò)分型面的淺槽排出去。一些壓鑄機(jī)也安裝有裝置，能在熱的金屬液充填型腔之前就抽空模具型腔中的氣體。 shallow 淺的、薄的 groove 槽、溝 vacuum 真空 evacuate 抽空、排空 charged into 沖向- 35 -CHAPTER 11 CASTINGThis reduces the amount of air trapped in the casting and produces more dense metal and mor

33、e sound casting.這樣就減少了鑄件中的含氣量，生產(chǎn)出更致密更光潔的金屬鑄件。 trapped in 把關(guān)在里dense 稠密的；濃厚的 sound 好的- 36 -CHAPTER 11 CASTINGPlaster molds are similar to sand molds, except that a mixture of plaster of Paris and water is poured into a flask that holds a pattern. After the plaster begins to set, the pattern is withdra

34、wn.石膏型模具鑄造與砂型鑄造像類似，除了熟石膏和水的混合物是澆注進(jìn)裝有模型型腔的砂箱。當(dāng)石膏模制成之后，模型被撤走。plaster of Paris 熟石膏石膏型鑄造視頻1石膏型鑄造視頻2- 37 -CHAPTER 11 CASTINGIf cores are required, they too are made of plaster. Molds and cores are baked to eliminate water and produce a porous mold through which entrapped air and gases can escape.如果需要型芯，它

35、們也被做成石膏型芯。烘烤模具和型芯排除水分，并生產(chǎn)出透氣的模具，通過(guò)它能夠使空氣或其他氣體排出。eliminate 排除 entrapped 誘捕, 使陷入圈套 porous 1. 多孔的 2. 滲水的;透氣的- 38 -CHAPTER 11 CASTINGInvestment molds are used for making precision castings. This casting technique is also known by the name lost wax process. The process is unique in that both a new patter

36、n and a new mold are required for each casting. 熔模鑄造用來(lái)制造精磨鑄件。這種鑄造技術(shù)也被叫做“失蠟鑄造”這個(gè)名字。每制造一個(gè)鑄件，都需要新模型和新模具，只有熔模鑄造有這一特點(diǎn)。wax 蠟 permanent 永久的熔模鑄造視頻- 39 -CHAPTER 11 CASTINGThermoplastic or thermosetting resins, low-melting alloys, mercury, and waxes have been used to make patterns. The pattern is, in reality,

37、 a die-casting or injection-molded plastic or wax part reproducing the details of the finished object. 熱塑性或熱固性樹(shù)脂，低熔點(diǎn)合金，水銀和石蠟已經(jīng)被用來(lái)做制作模型。事實(shí)上，模型是一個(gè)壓鑄件或注射模制作的塑料件或蠟件，這些塑件或蠟件能翻印出成品件的細(xì)節(jié)。 mercury 汞、水銀 reproducing 仿制、模擬、翻印finished object 成品、光制品- 40 -CHAPTER 11 CASTINGThe pattern is dipped into a mixture of w

38、ater and fine-grained refractory of creamy consistency. This forms a thin layer corresponding to facing sand on the surface of the pattern. 把模型浸入水和細(xì)粒耐火材料組成的油狀混合物。這樣模型表面的面砂就產(chǎn)生一層薄層的殼。dip 把浸入 fine-grained 細(xì)粒的 creamy 含乳油的consistency 稠度，稠性corresponding to 相對(duì)于、對(duì)應(yīng)于- 41 -CHAPTER 11 CASTING Coarse-grained si

39、lica is then sifted over the pattern and some of the particles are retained by the wet refractory coating. The coarse particles act as an anchor for the backing material of the mold. 大晶粒的硅土從模型上被淘汰下來(lái)，一些微粒通過(guò)液態(tài)耐火涂料被保留。那些大粒硅土可以當(dāng)作模具基體材料固定器。coarse-grained 粗粒的 sifted 過(guò)濾、挑選、淘汰 particles 微粒、小粒 anchor 錨、固定器-

40、42 -CHAPTER 11 CASTINGThe pattern is next placed in a flask that is filled with a substance such as silica flour bonded with ethyl silicate. The backing material sets, and the flask and contents are fired at high temperature to melt or burn out the pattern and drive off all moisture. 接下來(lái)，模型被放置在砂箱中，砂

41、箱中充滿著諸如被硅酸乙脂粘結(jié)在一起的硅砂粉這樣的材料?；w材料裝置和砂箱及其內(nèi)容物在高溫下開(kāi)始熔化或燒盡，從而除去掉所有的水分。silica flour 硅砂粉 silicate 硅酸乙脂moisture 水分- 43 -CHAPTER 11 CASTINGA clean mold cavity remains, which has the same shape as the original pattern. Casting is often accomplished by clamping the mold on top of a tilting furnace.這樣一個(gè)光滑的型腔就被保留

42、下來(lái)，它與原始模型有著相同的形狀。鑄件經(jīng)常通過(guò)被固定在傾轉(zhuǎn)爐的頂部的模具來(lái)完成。tilting furnace 傾轉(zhuǎn)爐CHAPTER 11 CASTING11.2Properties of Castingwrought form 精煉狀態(tài)ductility 延展性 toughness 韌性 void 縮孔 impurity content 雜志含量 gas bubble 氣泡 residual strength 殘余應(yīng)力 creep strength 抗蠕變強(qiáng)度 equiaxed grain 等軸晶 - 44 -CHAPTER 11 CASTING11.2Properties of Casti

43、ngequicohesive temperature 等內(nèi)聚性溫度f(wàn)luidity 流動(dòng)性amorphous glassy structure 無(wú)定形玻璃態(tài)組織 metglass 金屬玻璃，非晶態(tài)金屬supersaturation 過(guò)飽和ferromagnetic 鐵磁的，鐵磁體hysteresis 磁滯現(xiàn)象eddy 旋轉(zhuǎn)，漩渦 - 45 - 46 -CHAPTER 11 CASTINGDepending upon the particular casting process and the alloy used, the properties of castings vary greatly

44、. Mechanical properties are probably of greatest importance.由于鑄造工藝和使用合金的不同，鑄件的性能差別很大。其中，力學(xué)性能是很重要的。tilting furnace 傾轉(zhuǎn)爐- 47 -CHAPTER 11 CASTINGGenerally speaking, cast metal has inferior properties when compared to the same metal in wrought form. This is particularly true with respect to ductility and

45、 toughness at room temperature. However, proper design may cancel out these inherent shortcomings. 一般而言，相同的材料，相較于鍛造金屬而言，鑄造金屬具有較差的性能。尤其是在室溫下的延展性和韌性方面，更是如此。然而，正確的設(shè)計(jì)可能會(huì)抵消這些固有的缺點(diǎn)。inferior 差的，下級(jí)的 wrought 鍛造的 inherent 固有的with respect to 關(guān)于 ductility 延展性 toughness 韌性- 48 -CHAPTER 11 CASTINGThe lack of duct

46、ility probably arises from the void spaces that tend to be present in cast metal. The voids originate partly through evolution and entrapment of gases as the metal solidifies. In the case of die castings, there is the added problem of air trapped in the die.缺乏延展性可能由于鑄造金屬中往往存在縮孔造成的?？s孔的產(chǎn)生，部分是由于金屬凝固過(guò)程中

47、的氣體析出和滯留造成的。在壓鑄過(guò)程中，還會(huì)有排氣不良造成的問(wèn)題。arises from 由引起，起因于 originate 發(fā)源；發(fā)生evolution 變化，演進(jìn) entrapment 截留- 49 -CHAPTER 11 CASTINGMelting under a vacuum and casting into an evacuated mold increase the soundness of cast metal and lower the impurity content. These techniques result in better fabricating and ser

48、vice properties and are applied to production of high-quality alloy steels and other critical alloys. 在真空下融化并澆注進(jìn)真空模具中，能提高鑄造金屬的穩(wěn)定性，降低雜質(zhì)含量。這些技術(shù)帶來(lái)更好的加工特性及使用性能，并適用于生產(chǎn)高品質(zhì)合金鋼及其他重要合金。soundness 穩(wěn)定性fabricating 制備，制作- 50 -CHAPTER 11 CASTINGVoids also originate as a result of contraction of the metal as it sol

49、idifies. Voids of this type are both microscopic and macroscopic in nature and, because of their sharp angular form, are worse stress raisers than the rounded voids produced by gas bubbles.金屬的凝固收縮也會(huì)導(dǎo)致縮孔。這種類型的縮孔在形式上既有微觀的也有宏觀的，且由于它們?cè)谛螤钌洗嬖诩怃J的棱角，所以比氣泡所引起的圓形縮孔更容易產(chǎn)生應(yīng)力集中。contraction 收縮，緊縮 microscopic 微觀的ma

50、croscopic 宏觀的 stress raisers 局部應(yīng)力集中- 51 -CHAPTER 11 CASTINGShrinkage tendencies continue as the metal cools in the solid state and uneven rates of cooling produced by the geometry of the casting set up shrinkage stresses that may cause cooling cracks. Proper design and inspection should eliminate th

51、is type of structural defect.隨著固態(tài)金屬的冷卻，金屬繼續(xù)收縮。由于鑄件的幾何形狀，會(huì)導(dǎo)致冷卻速率不均勻，這會(huì)導(dǎo)致產(chǎn)生收縮應(yīng)力，并可能導(dǎo)致冷卻裂紋。適當(dāng)?shù)脑O(shè)計(jì)和檢驗(yàn)應(yīng)消除這種類型的結(jié)構(gòu)缺陷。contraction 收縮，緊縮 microscopic 微觀的macroscopic 宏觀的 stress raisers 局部應(yīng)力集中- 52 -CHAPTER 11 CASTINGStresses remaining in the casting may be insufficient to cause immediate fracture. However, upon

52、application of a small external load, fracture occurs. Residual stresses of this type can and should be eliminated by annealing the casting.鑄件中殘余的應(yīng)力可能不足以導(dǎo)致立即斷裂。然而，再加載一個(gè)小的外部載荷，就會(huì)發(fā)生斷裂。這種類型的殘余應(yīng)力可以并且應(yīng)該通過(guò)退火來(lái)消除。external 外部的annealing 退火- 53 -CHAPTER 11 CASTING Ductility is also affected by the grain shape

53、and grain orientation of the casting. Solidification shrinkage voids and low-melting, embrittling impurities tend to concentrate at the grain boundaries, causing planes of brittleness and weakness to develop in some castings as shown in Fig. 1l.2.延展性也受鑄件的晶粒形狀和晶粒取向影響。凝固縮孔和低熔點(diǎn)脆性雜質(zhì)傾向于集中于晶界，從而在某些鑄件形成脆性和

54、低強(qiáng)度的平面，如圖1l.2所示 。embrittling 脆化的- 54 -CHAPTER 11 CASTING Yield strength, creep strength, and ductility tend to be affected by cooling and solidification rates. Castings cooled very quickly, as in die and permanent mold castings, have fine, equiaxed grains.屈服強(qiáng)度，蠕變強(qiáng)度和延展性往往受到受冷卻和凝固速率的影響。在鍛壓模具和永久鑄模中，鑄件冷

55、卻速度非?？?，會(huì)形成細(xì)小的等軸晶。equiaxed 等軸的，各向等大的- 55 -CHAPTER 11 CASTING In precision castings, the cooling rate is sometimes intentionally kept low so that the grains are coarse and equiaxed.在精密鑄造中，有時(shí)特意保持較低的冷卻速度，以獲得粗大的等軸晶。intentionally 特意地，有意地- 56 -CHAPTER 11 CASTINGThe effect of grain size on yield strength ha

56、s been discussed earlier. Finer grain sizes not only improve strength, but also improve ductility. In regard to creep strength, fine grain sizes seem more desirable only for resisting deformation below the equicohesive temperature.前面已經(jīng)討論過(guò)晶粒大小對(duì)屈服強(qiáng)度的影響。細(xì)小的晶粒不僅提高強(qiáng)度，還提高延展性。至于蠕變強(qiáng)度，細(xì)晶粒只是在低于等強(qiáng)溫度時(shí)才能較好地抵御變形。

57、equicohesive 等強(qiáng)度的- 57 -CHAPTER 11 CASTINGAbove the equicohesive temperature coarse grain sizes improve strength. Thus, for high-temperature service at relatively low stresses and strain rates, precision-cast, slow-cooled, coarse-grained components are frequently desired. 在等強(qiáng)溫度以上，粗大晶粒提高強(qiáng)度。因此，在高溫，相對(duì)較低

58、的應(yīng)力和應(yīng)變速率下服役的機(jī)件，通常需要精密鑄造，緩慢冷卻，粗晶粒度。- 58 -CHAPTER 11 CASTINGThe very best high-temperature performance is achieved by controlling the solidification of precision-cast turbine buckets. In this application, single-crystal blades are formed having the orientation that best resists stress at high temperat

59、ure.最優(yōu)良的高溫性能是通過(guò)控制精密鑄造渦輪葉片凝固來(lái)實(shí)現(xiàn)。在此應(yīng)用中，形成的單晶葉片具有方向性，次方向是高溫下最能抵抗應(yīng)力的方向。turbine buckets 渦輪機(jī)葉片single-crystal 單晶- 59 -CHAPTER 11 CASTINGSurface smoothness is dependent upon the particular casting process. Sand castings have the poorest surface finish of all castings. Castings made in plastic-bonded shell-m

60、olds and plaster mold castings have somewhat better surface smoothness.表面光滑度是依賴于特定的鑄造工藝。砂型鑄件是所有鑄件中表面光潔度最差的。在塑性粘結(jié)殼模具和石膏模的鑄件具有較好的表面光潔度。plastic-bonded shell-molds 塑性粘結(jié)殼模具plaster mold 石膏模- 60 -CHAPTER 11 CASTINGMetal mold castings, if made in well-finished dies in good condition, have a very good surfac