第一篇：機(jī)械專業(yè)英語(yǔ)文章中英文對(duì)照

英語(yǔ)原文

NUMERICAL CONTROL

Numerical control(N/C)is a form of programmable automation in which the processing equipment is controlled by means of numbers, letters, and other symbols, The numbers, letters, and symbols are coded in an appropriate format to define a program of instructions for a particular work part or job.When the job changes, the program of instructions is changed.The capability to change the program is what makes N/C suitable for low-and medium-volume production.It is much easier to write programs than to make major alterations of the processing equipment.There are two basic types of numerically controlled machine tools：point—to—point and continuous—path(also called contouring).Point—to—point machines use unsynchronized motors, with the result that the position of the machining head Can be assured only upon completion of a movement, or while only one motor is running.Machines of this type are principally used for straight—line cuts or for drilling or boring.The N/C system consists of the following components：data input, the tape reader with the control unit, feedback devices, and the metal—cutting machine tool or other type of N/C equipment.Data input, also called “man—to—control link”, may be provided to the machine tool manually, or entirely by automatic means.Manual methods when used as the sole source of input data are restricted to a relatively small number of inputs.Examples of manually operated devices are keyboard dials, pushbuttons, switches, or thumbwheel selectors.These are located on a console near the machine.Dials ale analog devices usually connected to a syn-chro-type resolver or potentiometer.In most cases, pushbuttons, switches, and other similar types of selectors are digital input devices.Manual input requires that the operator set the controls for each operation.It is a slow and tedious process and is seldom justified except in elementary machining applications or in special cases.In practically all cases, information is automatically supplied to the control unit and the machine tool by cards, punched tapes, or by magnetic tape.Eight—channel punched paper tape is the most commonly used form of data input for conventional N/C systems.The coded instructions on the tape consist of sections of punched holes called blocks.Each block represents a machine function, a machining operation, or a combination of the two.The entire N/C program on a tape is made up of an accumulation of these successive data blocks.Programs resulting in long tapes all wound on reels like motion-picture film.Programs on relatively short tapes may be continuously repeated by joining the two ends of the tape to form a loop.Once installed, the tape is used again and again without further handling.In this case, the operator simply loads and1

unloads the parts.Punched tapes ale prepared on type writers with special tape—punching attachments or in tape punching units connected directly to a computer system.Tape production is rarely error-free.Errors may be initially caused by the part programmer, in card punching or compilation, or as a result of physical damage to the tape during handling, etc.Several trial runs are often necessary to remove all errors and produce an acceptable working tape.While the data on the tape is fed automatically, the actual programming steps ale done manually.Before the coded tape may be prepared, the programmer, often working with a planner or a process engineer, must select the appropriate N/C machine tool, determine the kind of material to be machined, calculate the speeds and feeds, and decide upon the type of tooling needed.The dimensions on the part print are closely examined to determine a suitable zero reference point from which to start the program.A program manuscript is then written which gives coded numerical instructions describing the sequence of operations that the machine tool is required to follow to cut the part to the drawing specifications.The control unit receives and stores all coded data until a complete block of information has been accumulated.It then interprets the coded instruction and directs the machine tool through the required motions.The function of the control unit may be better understood by comparing it to the action of a dial telephone, where, as each digit is dialed, it is stored.When the entire number has been dialed, the equipment becomes activated and the call is completed.Silicon photo diodes, located in the tape reader head on the control unit, detect light as it passes through the holes in the moving tape.The light beams are converted to electrical energy, which is amplified to further strengthen the signal.The signals are then sent to registers in the control unit, where actuation signals are relayed to the machine tool drives.Some photoelectric devices are capable of reading at rates up to 1000 characters per second.High reading rates are necessary to maintain continuous machine—tool motion；otherwise dwell marks may be generated by the cutter on the part during contouring operations.The reading device must be capable of reading data blocks at a rate faster than the control system can process the data.A feedback device is a safeguard used on some N/C installations to constantly compensate for errors between the commanded position and the actual location of the moving slides of the machine tool.An N/C machine equipped with this kind of a direct feedback checking device has what is known as a closed-loop system.Positioning control is accomplished by a sensor which, during the actual operation, records the position of the slides and relays this information back to the control unit.Signals thus received ale compared to input signals on the tape, and any discrepancy between them is automatically rectified.In an alternative system, called an open—loop system, the machine is positioned solely by stepping motor drives in response to commands by a controllers.There is one basic type of NC motions.Point-to-point or Positional Control In point-to-point control the machine tool elements(tools, table, etc.)are moved to programmed locations and the machining operations performed

after the motions are completed.The path or speed of movement between locations is unimportant;only the coordinates of the end points of the motions are accurately controlled.This type of control is suitable for drill presses and some boring machines, where drilling, tapping, or boring operations must be performed at various locations on the work piece.Straight-Line or Linear Control Straight-Line control systems are able to move the cutting tool parallel to one of the major axes of the machine tool at a controlled rate suitable for machining.It is normally only possible to move in one direction at a time, so angular cuts on the work piece are not possible, consequently, for milling machines, only rectangular configurations can be machined or for lathes only surfaces parallel or perpendicular to the spindle axis can be machined.This type of controlled motion is often referred to as linear control or a half-axis of control.Machines with this form of control are also capable of point-to-point control.The original N/C used the closed—loop system.Of the two systems, closed and open loop, closed loop is more accurate and, as a consequence, is generally more expensive.Initially, open—loop systems were used almost entirely for light-duty applications because of inherent power limitations previously associated with conventional electric stepping motors.Recent advances in the development of electro hydraulic stepping motors have led to increasingly heavier machine load applications.中文譯文

數(shù)控技術(shù)

數(shù)控是可編程自動(dòng)化技術(shù)的一種形式,通過數(shù)字、字母和其他符號(hào)來控制加工設(shè)備。數(shù)字、字母和符號(hào)用適當(dāng)?shù)母袷骄幋a為一個(gè)特定工件定義指令程序。當(dāng)工件改變時(shí),指令程序就改變。這種改變程序的能力使數(shù)控適合于中、小批量生產(chǎn),寫一段新程序遠(yuǎn)比對(duì)加工設(shè)備做大的改動(dòng)容易得多。

數(shù)控機(jī)床有兩種基本形式：點(diǎn)位控制和連續(xù)控制(也稱為輪廓控制)。點(diǎn)位控制機(jī)床采用異步電動(dòng)機(jī),因此,主軸的定位只能通過完成一個(gè)運(yùn)動(dòng)或一個(gè)電動(dòng)機(jī)的轉(zhuǎn)動(dòng)來實(shí)現(xiàn)。這種機(jī)床主要用于直線切削或鉆孔、鏜孔等場(chǎng)合。

數(shù)控系統(tǒng)由下列組件組成：數(shù)據(jù)輸入裝置,帶控制單元的磁帶閱讀機(jī),反饋裝置和切削機(jī)床或其他形式的數(shù)控設(shè)備。

數(shù)據(jù)輸人裝置,也稱“人機(jī)聯(lián)系裝置”,可用人工或全自動(dòng)方法向機(jī)床提供數(shù)據(jù)。人工方法作為輸人數(shù)據(jù)唯一方法時(shí),只限于少量輸入。人工輸入裝置有鍵盤,撥號(hào)盤,按鈕,開關(guān)或撥輪選擇開關(guān),這些都位于機(jī)床附近的一個(gè)控制臺(tái)上。撥號(hào)盤通常連到一個(gè)同步解析器或電位計(jì)的模擬裝置上。在大多數(shù)情況下,按鈕、開關(guān)和其他類似的旋鈕是數(shù)據(jù)輸入元件。人工輸入需要操作者控制每個(gè)操作,這是一個(gè)既慢又單調(diào)的過程,除了簡(jiǎn)單加工場(chǎng)合或特殊情況,已很少使用。

幾乎所有情況下,信息都是通過卡片、穿孔紙帶或磁帶自動(dòng)提供給控制單元。在傳統(tǒng)的數(shù)控系統(tǒng)中,八信道穿孔紙帶是最常用的數(shù)據(jù)輸入形式,紙帶上的編碼指令由一系列稱為程序塊的穿孔組成。每一個(gè)程序塊代表一種加工功能、一種操作或兩者的組合。紙帶上的整個(gè)數(shù)控程序由這些連續(xù)數(shù)據(jù)單元連接而成。帶有程序的長(zhǎng)帶子像電影膠片一樣繞在盤子上,相對(duì)較短的帶子上的程序可通過將紙帶兩端連接形成一個(gè)循環(huán)而連續(xù)不斷地重復(fù)使用。帶子一旦安裝好,就可反復(fù)使用而無需進(jìn)一步處理。此時(shí),操作者只是簡(jiǎn)單地上、下工件。穿孔紙帶是在帶有特制穿孔附件的打字機(jī)或直接連到計(jì)算機(jī)上的紙帶穿孔裝置上做成的。紙帶制造很少不出錯(cuò),錯(cuò)誤可能由編程、卡片穿孔或編碼、紙帶穿孔時(shí)的物理?yè)p害等形成。通常,必須要試走幾次來排除錯(cuò)誤,才能得到一個(gè)可用的工作紙帶。

雖然紙帶上的數(shù)據(jù)是自動(dòng)進(jìn)給的,但實(shí)際編程卻是手工完成的,在編碼紙帶做好前,編程者經(jīng)常要和一個(gè)計(jì)劃人員或工藝工程師一起工作,選擇合適的數(shù)控機(jī)床,決定加工材料,計(jì)算切削速度和進(jìn)給速度,決定所需刀具類型,仔細(xì)閱讀零件圖上尺寸,定下合適的程序開始的零參考點(diǎn),然后寫出程序清單,其上記載有描述加工順序的編碼數(shù)控指令,機(jī)床按順序加工工件到圖樣要求。

控制單元接受和儲(chǔ)存編碼數(shù)據(jù),直至形成一個(gè)完整的信息程序塊,然后解釋數(shù)控指令,并引導(dǎo)機(jī)床得到所需運(yùn)動(dòng)。

為更好理解控制單元的作用,可將它與撥號(hào)電話進(jìn)行比較,即每撥一個(gè)數(shù)字,就儲(chǔ)存一個(gè),當(dāng)整個(gè)數(shù)字撥好后,電話就被激活,也就完成了呼叫。

裝在控制單元里的紙帶閱讀機(jī),通過其內(nèi)的硅光二極管,檢測(cè)到穿過移動(dòng)紙帶上的孔漏

過的光線,將光束轉(zhuǎn)變成電能,并通過放大來進(jìn)一步加強(qiáng)信號(hào),然后將信號(hào)送到控制單元里的寄存器,由它將動(dòng)作信號(hào)傳到機(jī)床驅(qū)動(dòng)裝置。

有些光電裝置能以高達(dá)每秒1000個(gè)字節(jié)的速度閱讀,這對(duì)保持機(jī)床連續(xù)動(dòng)作是必須的,否則,在輪廓加工時(shí),刀具可能在工件上產(chǎn)生劃痕。閱讀裝置必須要能以比控制系統(tǒng)處理數(shù)據(jù)更快的速度來閱讀數(shù)據(jù)程序塊。

反饋裝置是用在一些數(shù)控設(shè)備上的安全裝置,它可連續(xù)補(bǔ)償控制位置與機(jī)床運(yùn)動(dòng)滑臺(tái)的實(shí)際位置之間的誤差。裝有這種直接反饋檢查裝置的數(shù)控機(jī)床有一個(gè)閉環(huán)系統(tǒng)裝置。位置控制通過傳感器實(shí)現(xiàn),在實(shí)際工作時(shí),記錄下滑臺(tái)的位置,并將這些信息送回控制單元。接受到的信號(hào)與紙帶輸入的信號(hào)相比較,它們之間的任何偏差都可得到糾正。

在另一個(gè)稱為開環(huán)的系統(tǒng)中,機(jī)床僅由響應(yīng)控制器命令的步進(jìn)電動(dòng)機(jī)驅(qū)動(dòng)定位,工件的精度幾乎完全取決于絲杠的精度和機(jī)床結(jié)構(gòu)的剛度。有幾個(gè)理由可以說明步進(jìn)電機(jī)是一個(gè)自動(dòng)化申請(qǐng)的非常有用的驅(qū)動(dòng)裝置。對(duì)于一件事物,它被不連續(xù)直流電壓脈沖驅(qū)使,是來自數(shù)傳計(jì)算機(jī)和其他的自動(dòng)化的非常方便的輸出控制系統(tǒng)。當(dāng)多數(shù)是索引或其他的自動(dòng)化申請(qǐng)所必備者的時(shí)候,步進(jìn)電機(jī)對(duì)運(yùn)行一個(gè)精確的有角進(jìn)步也是理想的。因?yàn)榭刂葡到y(tǒng)不需要監(jiān)聽就提供特定的輸出指令而且期待系統(tǒng)適當(dāng)?shù)胤磻?yīng)的公開-環(huán)操作造成一個(gè)回應(yīng)環(huán),步進(jìn)電機(jī)是理想的。一些工業(yè)的機(jī)械手使用高抬腿運(yùn)步的馬乘汽車駕駛員,而且步進(jìn)電機(jī)是有用的在數(shù)字受約束的工作母機(jī)中。這些申請(qǐng)的大部分是公開-環(huán) ,但是雇用回應(yīng)環(huán)檢測(cè)受到驅(qū)策的成份位置是可能的。環(huán)的一個(gè)分析者把真實(shí)的位置與需要的位置作比較,而且不同是考慮過的錯(cuò)誤。那然后駕駛員能發(fā)行對(duì)步進(jìn)電機(jī)的電脈沖,直到錯(cuò)誤被減少對(duì)準(zhǔn)零位。在這個(gè)系統(tǒng)中,沒有信息反饋到控制單元的自矯正過程。出現(xiàn)誤動(dòng)作時(shí),控制單元繼續(xù)發(fā)出電脈沖。比如,一臺(tái)數(shù)控銑床的工作臺(tái)突然過載,阻力矩超過電機(jī)轉(zhuǎn)矩時(shí),將沒有響應(yīng)信號(hào)送回到控制器。因?yàn)?步進(jìn)電機(jī)對(duì)載荷變化不敏感,所以許多數(shù)控系統(tǒng)設(shè)計(jì)允許電機(jī)停轉(zhuǎn)。然而,盡管有可能損壞機(jī)床結(jié)構(gòu)或機(jī)械傳動(dòng)系統(tǒng),也有使用帶有特高轉(zhuǎn)矩步進(jìn)電機(jī)的其他系統(tǒng),此時(shí),電動(dòng)機(jī)有足夠能力來應(yīng)付系統(tǒng)中任何偶然事故。

最初的數(shù)控系統(tǒng)采用開環(huán)系統(tǒng)。在開、閉環(huán)兩種系統(tǒng)中,閉環(huán)更精確,一般說來更昂貴。起初,因?yàn)樵葌鹘y(tǒng)的步進(jìn)電動(dòng)機(jī)的功率限制,開環(huán)系統(tǒng)幾乎全部用于輕加工場(chǎng)合,最近出現(xiàn)的電液步進(jìn)電動(dòng)機(jī)已越來越多地用于較重的加工領(lǐng)域。

第二篇：機(jī)械專業(yè)英語(yǔ)文章 中英文對(duì)照

Types of Materials 材料的類型

Materials may be grouped in several ways.Scientists often classify materials by their state: solid, liquid, or gas.They also separate them into organic(once living)and inorganic(never living)materials.材料可以按多種方法分類?？茖W(xué)家常根據(jù)狀態(tài)將材料分為：固體、液體或氣體。他們也把材料分為有機(jī)材料(曾經(jīng)有生命的)和無機(jī)材料(從未有生命的)。

For industrial purposes, materials are divided into engineering materials or nonengineering materials.Engineering materials are those used in manufacture and become parts of products.就工業(yè)效用而言，材料被分為工程材料和非工程材料。那些用于加工制造并成為產(chǎn)品組成部分的就是工程材料。

Nonengineering materials are the chemicals, fuels, lubricants, and other materials used in the manufacturing process, which do not become part of the product.非工程材料則是化學(xué)品、燃料、潤(rùn)滑劑以及其它用于加工制造過程但不成為產(chǎn)品組成部分的材料。

Engineering materials may be further subdivided into: ①M(fèi)etal ②Ceramics ③Composite ④Polymers, etc.工程材料還能進(jìn)一步細(xì)分為：①金屬材料②陶瓷材料③復(fù)合材料 ④聚合材料，等等。

Metals and Metal Alloys 金屬和金屬合金

Metals are elements that generally have good electrical and thermal conductivity.Many metals have high strength, high stiffness, and have good ductility.金屬就是通常具有良好導(dǎo)電性和導(dǎo)熱性的元素。許多金屬具有高強(qiáng)度、高硬度以及良好的延展性。

Some metals, such as iron, cobalt and nickel, are magnetic.At low temperatures, some

metals

and

intermetallic

compounds

become superconductors.某些金屬能被磁化，例如鐵、鈷和鎳。在極低的溫度下，某些金屬和金屬化合物能轉(zhuǎn)變成超導(dǎo)體。

What is the difference between an alloy and a pure metal? Pure metals are elements which come from a particular area of the periodic table.Examples of pure metals include copper in electrical wires and aluminum in cooking foil and beverage cans.合金與純金屬的區(qū)別是什么？純金屬是在元素周期表中占據(jù)特定位置的元素。

例如電線中的銅和制造烹飪箔及飲料罐的鋁。

Alloys contain more than one metallic element.Their properties can be changed by changing the elements present in the alloy.Examples of metal alloys include stainless steel which is an alloy of iron, nickel, and chromium;and gold jewelry which usually contains an alloy of gold and nickel.合金包含不止一種金屬元素。合金的性質(zhì)能通過改變其中存在的元素而改變。金屬合金的例子有：不銹鋼是一種鐵、鎳、鉻的合金，以及金飾品通常含有金鎳合金。

Why are metals and alloys used? Many metals and alloys have high densities and are used in applications which require a high mass-to-volume ratio.為什么要使用金屬和合金？許多金屬和合金具有高密度，因此被用在需要較高質(zhì)量體積比的場(chǎng)合。

Some metal alloys, such as those based on aluminum, have low densities and are used in aerospace applications for fuel economy.Many alloys also have high fracture toughness, which means they can withstand impact and are durable.某些金屬合金，例如鋁基合金，其密度低，可用于航空航天以節(jié)約燃料。許多合金還具有高斷裂韌性，這意味著它們能經(jīng)得起沖擊并且是耐用的

What are some important properties of metals?

Density is defined as a material’s mass divided by its volume.Most metals have relatively high densities, especially compared to polymers.金屬有哪些重要特性？

密度定義為材料的質(zhì)量與其體積之比。大多數(shù)金屬密度相對(duì)較高，尤其是和聚合物相比較而言。

Materials with high densities often contain atoms with high atomic numbers, such as gold or lead.However, some metals such as aluminum or magnesium have low densities, and are used in applications that require other metallic properties but also require low weight.高密度材料通常由較大原子序數(shù)原子構(gòu)成，例如金和鉛。然而，諸如鋁和鎂之類的一些金屬則具有低密度，并被用于既需要金屬特性又要求重量輕的場(chǎng)合。

Fracture toughness can be described as a material’s ability to avoid fracture, especially when a flaw is introduced.Metals can generally contain nicks and dents without weakening very much, and are impact resistant.A football player counts on this when he trusts that his facemask won’t shatter.斷裂韌性可以描述為材料防止斷裂特別是出現(xiàn)缺陷時(shí)不斷裂的能力。金屬一般能在有缺口和凹痕的情況下不顯著削弱，并且能抵抗沖擊。橄欖球運(yùn)動(dòng)員據(jù)此相信他的面罩不會(huì)裂成碎片。

Plastic deformation is the ability of bend or deform before breaking.As engineers, we usually design materials so that they don’t deform under normal conditions.You don’t want your car to lean to the east after a strong west wind.塑性變形就是在斷裂前彎曲或變形的能力。作為工程師，設(shè)計(jì)時(shí)通常要使材料在正常條件下不變形。沒有人愿意一陣強(qiáng)烈的西風(fēng)過后自己的汽車向東傾斜。

However, sometimes we can take advantage of plastic deformation.The crumple zones in a car absorb energy by undergoing plastic deformation before they break.然而，有時(shí)我們也能利用塑性變形。汽車上壓皺的區(qū)域在它們斷裂前通過經(jīng)歷塑性變形來吸收能量。

The atomic bonding of metals also affects their properties.In metals, the outer valence electrons are shared among all atoms, and are free to travel everywhere.Since electrons conduct heat and electricity, metals make good cooking pans and electrical wires.金屬的原子連結(jié)對(duì)它們的特性也有影響。在金屬內(nèi)部，原子的外層階電子由所有原子共享并能到處自由移動(dòng)。由于電子能導(dǎo)熱和導(dǎo)電，所以用金屬可以制造好的烹飪鍋和電線。

It is impossible to see through metals, since these valence electrons absorb any photons of light which reach the metal.No photons pass through.因?yàn)檫@些階電子吸收到達(dá)金屬的光子，所以透過金屬不可能看得見。沒有光子

能通過金屬。

Alloys are compounds consisting of more than one metal.Adding other metals can affect the density, strength, fracture toughness, plastic deformation, electrical conductivity and environmental degradation.合金是由一種以上金屬組成的混合物。加一些其它金屬能影響密度、強(qiáng)度、斷裂韌性、塑性變形、導(dǎo)電性以及環(huán)境侵蝕。

For example, adding a small amount of iron to aluminum will make it stronger.Also, adding some chromium to steel will slow the rusting process, but will make it more brittle.例如，往鋁里加少量鐵可使其更強(qiáng)。同樣，在鋼里加一些鉻能減緩它的生銹過程，但也將使它更脆。

Ceramics and Glasses 陶瓷和玻璃

A ceramic is often broadly defined as any inorganic nonmetallic material． By this definition, ceramic materials would also include glasses;however, many materials scientists add the stipulation that “ceramic” must also be crystalline.陶瓷通常被概括地定義為無機(jī)的非金屬材料。照此定義，陶瓷材料也應(yīng)包括玻璃；然而許多材料科學(xué)家添加了“陶瓷”必須同時(shí)是晶體物組成的約定。

A glass is an inorganic nonmetallic material that does not have a crystalline structure.Such materials are said to be amorphous.玻璃是沒有晶體狀結(jié)構(gòu)的無機(jī)非金屬材料。這種材料被稱為非結(jié)晶質(zhì)材料。Properties of Ceramics and Glasses Some of the useful properties of ceramics and glasses include high melting temperature, low density, high strength, stiffness, hardness, wear resistance, and corrosion resistance.陶瓷和玻璃的特性

高熔點(diǎn)、低密度、高強(qiáng)度、高剛度、高硬度、高耐磨性和抗腐蝕性是陶瓷和玻璃的一些有用特性。

Many ceramics are good electrical and thermal insulators.Some ceramics have special properties: some ceramics are magnetic materials;some are piezoelectric materials;and a few special ceramics are superconductors at very low temperatures.Ceramics and glasses have one major drawback: they are brittle.許多陶瓷都是電和熱的良絕緣體。某些陶瓷還具有一些特殊性能：有些是磁性材料，有些是壓電材料，還有些特殊陶瓷在極低溫度下是超導(dǎo)體。陶瓷和玻璃都有一個(gè)主要的缺點(diǎn)：它們?nèi)菀灼扑椤?/p>

Ceramics are not typically formed from the melt.This is because most

ceramics will crack extensively(i.e.form a powder)upon cooling from the liquid state.陶瓷一般不是由熔化形成的。因?yàn)榇蠖鄶?shù)陶瓷在從液態(tài)冷卻時(shí)將會(huì)完全破碎(即形成粉末)。

Hence, all the simple and efficient manufacturing techniques used for glass production such as casting and blowing, which involve the molten state, cannot be used for the production of crystalline ceramics.Instead, “sintering” or “firing” is the process typically used.因此，所有用于玻璃生產(chǎn)的簡(jiǎn)單有效的—諸如澆鑄和吹制這些涉及熔化的技術(shù)都不能用于由晶體物組成的陶瓷的生產(chǎn)。作為替代，一般采用“燒結(jié)”或“焙燒”工藝。

In sintering, ceramic powders are processed into compacted shapes and then heated to temperatures just below the melting point.At such temperatures, the powders react internally to remove porosity and fully dense articles can be obtained.在燒結(jié)過程中，陶瓷粉末先擠壓成型然后加熱到略低于熔點(diǎn)溫度。在這樣的溫度下，粉末內(nèi)部起反應(yīng)去除孔隙并得到十分致密的物品。

An optical fiber contains three layers: a core made of highly pure glass with a high refractive index for the light to travel, a middle layer of glass with a lower refractive index known as the cladding which protects the core

glass from scratches and other surface imperfections, and an out polymer jacket to protect the fiber from damage.光導(dǎo)纖維有三層：核心由高折射指數(shù)高純光傳輸玻璃制成，中間層為低折射指數(shù)玻璃，是保護(hù)核心玻璃表面不被擦傷和完整性不被破壞的所謂覆層，外層是聚合物護(hù)套，用于保護(hù)光導(dǎo)纖維不受損。

In order for the core glass to have a higher refractive index than the cladding, the core glass is doped with a small, controlled amount of an impurity, or dopant, which causes light to travel slower, but does not absorb the light.為了使核心玻璃有比覆層大的折射指數(shù)，在其中摻入微小的、可控?cái)?shù)量的能減緩光速而不會(huì)吸收光線的雜質(zhì)或攙雜劑。

Because the refractive index of the core glass is greater than that of the cladding, light traveling in the core glass will remain in the core glass due to total internal reflection as long as the light strikes the core/cladding interface at an angle greater than the critical angle.由于核心玻璃的折射指數(shù)比覆層大，只要在全內(nèi)反射過程中光線照射核心/覆層分界面的角度比臨界角大，在核心玻璃中傳送的光線將仍保留在核心玻璃中。

The total internal reflection phenomenon, as well as the high purity of the core glass, enables light to travel long distances with little loss of intensity.全內(nèi)反射現(xiàn)象與核心玻璃的高純度一樣，使光線幾乎無強(qiáng)度損耗傳遞長(zhǎng)距離成為可能。

Composites 復(fù)合材料

Composites are formed from two or more types of materials.Examples include polymer/ceramic and metal/ceramic composites.Composites are used because overall properties of the composites are superior to those of the individual components.復(fù)合材料由兩種或更多材料構(gòu)成。例子有聚合物/陶瓷和金屬/陶瓷復(fù)合材料。之所以使用復(fù)合材料是因?yàn)槠淙嫘阅軆?yōu)于組成部分單獨(dú)的性能。

For example: polymer/ceramic composites have a greater modulus than the polymer component, but aren’t as brittle as ceramics.Two types of composites are: fiber-reinforced composites and particle-reinforced composites.例如：聚合物/陶瓷復(fù)合材料具有比聚合物成分更大的模量，但又不像陶瓷那樣易碎。

復(fù)合材料有兩種：纖維加強(qiáng)型復(fù)合材料和微粒加強(qiáng)型復(fù)合材料。Fiber-reinforced Composites Reinforcing fibers can be made of metals, ceramics, glasses, or polymers that have been turned into graphite and known as carbon fibers.Fibers

increase the modulus of the matrix material.纖維加強(qiáng)型復(fù)合材料

加強(qiáng)纖維可以是金屬、陶瓷、玻璃或是已變成石墨的被稱為碳纖維的聚合物。纖維能加強(qiáng)基材的模量。

The strong covalent bonds along the fiber’s length give them a very high modulus in this direction because to break or extend the fiber the bonds must also be broken or moved.沿著纖維長(zhǎng)度有很強(qiáng)結(jié)合力的共價(jià)結(jié)合在這個(gè)方向上給予復(fù)合材料很高的模量，因?yàn)橐獡p壞或拉伸纖維就必須破壞或移除這種結(jié)合。

Fibers are difficult to process into composites, making fiber-reinforced composites relatively expensive.把纖維放入復(fù)合材料較困難，這使得制造纖維加強(qiáng)型復(fù)合材料相對(duì)昂貴。Fiber-reinforced composites are used in some of the most advanced, and therefore most expensive sports equipment, such as a time-trial racing bicycle frame which consists of carbon fibers in a thermoset polymer matrix.纖維加強(qiáng)型復(fù)合材料用于某些最先進(jìn)也是最昂貴的運(yùn)動(dòng)設(shè)備，例如計(jì)時(shí)賽競(jìng)賽用自行車骨架就是用含碳纖維的熱固塑料基材制成的。

Body parts of race cars and some automobiles are composites made of glass fibers(or fiberglass)in a thermoset matrix.競(jìng)賽用汽車和某些機(jī)動(dòng)車的車體部件是由含玻璃纖維(或玻璃絲)的熱固塑料基材制成的。

Fibers have a very high modulus along their axis, but have a low modulus perpendicular to their axis.Fiber composite manufacturers often rotate layers of fibers to avoid directional variations in the modulus.纖維在沿著其軸向有很高的模量，但垂直于其軸向的模量卻較低。纖維復(fù)合材料的制造者往往旋轉(zhuǎn)纖維層以防模量產(chǎn)生方向變化。

Particle-reinforced composites Particles used for reinforcing include ceramics and glasses such as small mineral particles, metal particles such as aluminum, and amorphous materials, including polymers and carbon black.微粒加強(qiáng)型復(fù)合材料[番茄用戶1] [番茄用戶2] [番茄用戶3] [番茄用戶4] [番茄用戶5] [番茄用戶6] 用于加強(qiáng)的微粒包含了陶瓷和玻璃之類的礦物微粒，鋁之類的金屬微粒以及包括聚合物和碳黑的非結(jié)晶質(zhì)微粒。

Particles are used to increase the modulus of the matrix, to decrease the permeability of the matrix, to decrease the ductility of the matrix.An example of particle-reinforced composites is an automobile tire which has carbon black particles in a matrix of polyisobutylene elastomeric polymer.微粒用于增加基材的模量、減少基材的滲透性和延展性。微粒加強(qiáng)型復(fù)合材料的一個(gè)例子是機(jī)動(dòng)車胎，它就是在聚異丁烯人造橡膠聚合物基材中加入了碳黑微粒。

Polymers 聚合材料

A polymer has a repeating structure, usually based on a carbon backbone.The repeating structure results in large chainlike molecules.Polymers are useful because they are lightweight, corrosion resistant, easy to process at low temperatures and generally inexpensive.聚合物具有一般是基于碳鏈的重復(fù)結(jié)構(gòu)。這種重復(fù)結(jié)構(gòu)產(chǎn)生鏈狀大分子。由于重量輕、耐腐蝕、容易在較低溫度下加工并且通常較便宜，聚合物是很有用的。

Some important characteristics of polymers include their size(or molecular weight), softening and melting points, crystallinity, and structure.The mechanical properties of polymers generally include low strength and high toughness.Their strength is often improved using reinforced composite structures.聚合材料具有一些重要特性，包括尺寸(或分子量)、軟化及熔化點(diǎn)、結(jié)晶度和結(jié)構(gòu)。聚合材料的機(jī)械性能一般表現(xiàn)為低強(qiáng)度和高韌性。它們的強(qiáng)度通常可采用加強(qiáng)復(fù)合結(jié)構(gòu)來改善。

Important Characteristics of Polymers Size.Single polymer molecules typically have molecular weights between 10,000 and 1,000,000g/mol—that can be more than 2,000 repeating units

depending on the polymer structure!聚合材料的重要特性

尺寸：?jiǎn)蝹€(gè)聚合物分子一般分子量為10,000到1,000,000g/mol之間，具體取決于聚合物的結(jié)構(gòu)—這可以比2,000個(gè)重復(fù)單元還多。

The mechanical properties of a polymer are significantly affected by the molecular weight, with better engineering properties at higher molecular weights.聚合物的分子量極大地影響其機(jī)械性能，分子量越大，工程性能也越好。Thermal transitions.The softening? point(glass transition temperature)and the melting point of a polymer will determine which it will be suitable for applications.These temperatures usually determine the upper limit for which a polymer can be used.熱轉(zhuǎn)換性：聚合物的軟化點(diǎn)(玻璃狀轉(zhuǎn)化溫度)和熔化點(diǎn)決定了它是否適合應(yīng)用。這些溫度通常決定聚合物能否使用的上限。

For example, many industrially important polymers have glass transition temperatures near the boiling point of water(100℃, 212℉), and they are most useful for room temperature applications.Some specially engineered polymers can withstand temperatures as high as 300℃(572℉).例如，許多工業(yè)上的重要聚合物其玻璃狀轉(zhuǎn)化溫度接近水的沸點(diǎn)(100℃，212℉)，它們被廣泛用于室溫下。而某些特別制造的聚合物能經(jīng)受住高達(dá)300℃(572℉)的溫度。

Crystallinity.Polymers can be crystalline or amorphous, but they usually have a combination of crystalline and amorphous structures(semi-crystalline).結(jié)晶度：聚合物可以是晶體狀的或非結(jié)晶質(zhì)的，但它們通常是晶體狀和非結(jié)晶質(zhì)結(jié)構(gòu)的結(jié)合物(半晶體)。

Interchain interactions.The polymer chains can be free to slide past one another(thermo-plastic)or they can be connected to each other with crosslinks(thermoset or elastomer).Thermo-plastics can be reformed and recycled, while thermosets and elastomers are not reworkable.原子鏈間的相互作用：聚合物的原子鏈可以自由地彼此滑動(dòng)(熱可塑性)或通過交鍵互相連接(熱固性或彈性)。熱可塑性材料可以重新形成和循環(huán)使用，而熱固性與彈性材料則是不能再使用的。

Intrachain structure.The chemical structure of the chains also has a tremendous effect on the properties.Depending on the structure the polymer may be hydrophilic or hydrophobic(likes or hates water), stiff or flexible, crystalline or amorphous, reactive or unreactive.鏈內(nèi)結(jié)構(gòu)：原子鏈的化學(xué)結(jié)構(gòu)對(duì)性能也有很大影響。根據(jù)各自的結(jié)構(gòu)不同，聚合物可以是親水的或憎水的(喜歡或討厭水)、硬的或軟的、晶體狀的或非結(jié)晶質(zhì)的、易起反應(yīng)的或不易起反應(yīng)的。

The understanding of heat treatment is embraced by the broader study of metallurgy.Metallurgy is the physics, chemistry, and engineering related to metals from ore extraction to the final product.對(duì)熱處理的理解包含于對(duì)冶金學(xué)較廣泛的研究。冶金學(xué)是物理學(xué)、化學(xué)和涉及金屬?gòu)牡V石提煉到最后產(chǎn)物的工程學(xué)。

Heat treatment is the operation of heating and cooling a metal in its solid state to change its physical properties.According to the procedure used, steel can be hardened to resist cutting action and abrasion, or it can be softened to permit machining.熱處理是將金屬在固態(tài)加熱和冷卻以改變其物理性能的操作。按所采用的步驟，鋼可以通過硬化來抵抗切削和磨損，也可以通過軟化來允許機(jī)加工。

With the proper heat treatment internal stresses may be removed, grain size reduced, toughness increased, or a hard surface produced on a ductile interior.The analysis of the steel must be known because small percentages of certain elements, notably carbon, greatly affect the physical properties.使用合適的熱處理可以去除內(nèi)應(yīng)力、細(xì)化晶粒、增加韌性或在柔軟材料上覆蓋堅(jiān)硬的表面。因?yàn)槟承┰?尤其是碳)的微小百分比極大地影響物理性能，所以必須知道對(duì)鋼的分析。

Alloy steel owe their properties to the presence of one or more elements other than carbon, namely nickel, chromium, manganese, molybdenum, tungsten, silicon, vanadium, and copper.Because of their improved physical properties they are used commercially in many ways not possible with carbon steels.合金鋼的性質(zhì)取決于其所含有的除碳以外的一種或多種元素，如鎳、鉻、錳、鉬、鎢、硅、釩和銅。由于合金鋼改善的物理性能，它們被大量使用在許多碳鋼不適用的地方。

The following discussion applies principally to the heat treatment of ordinary commercial steels known as plain carbon steels.With this process the rate of cooling is the controlling factor, rapid cooling from above the critical range results in hard structure, whereas very slow cooling produces the opposite effect.下列討論主要針對(duì)被稱為普通碳鋼的工業(yè)用鋼而言。熱處理時(shí)冷卻速率是控制要素，從高于臨界溫度快速冷卻導(dǎo)致堅(jiān)硬的組織結(jié)構(gòu)，而緩慢冷卻則產(chǎn)生相反效果。

A Simplified Iron-carbon Diagram 簡(jiǎn)化鐵碳狀態(tài)圖

If we focus only on the materials normally known as steels, a simplified diagram is often used.如果只把注意力集中于一般所說的鋼上，經(jīng)常要用到簡(jiǎn)化鐵碳狀態(tài)圖。

Those portions of the iron-carbon diagram near the delta region and those above 2% carbon content are of little importance to the engineer and are deleted.A simplified diagram, such as the one in Fig.2.1, focuses on the eutectoid region and is quite useful in understanding the properties and processing of steel.鐵碳狀態(tài)圖中靠近三角區(qū)和含碳量高于2%的那些部分對(duì)工程師而言不重要，因此將它們刪除。如圖2.1所示的簡(jiǎn)化鐵碳狀態(tài)圖將焦點(diǎn)集中在共析區(qū)，這對(duì)理解鋼的性能和處理是十分有用的。

The key transition described in this diagram is the decomposition of single-phase austenite(γ)to the two-phase ferrite plus carbide structure as temperature drops.在此圖中描述的關(guān)鍵轉(zhuǎn)變是單相奧氏體(γ)隨著溫度下降分解成兩相鐵素體加滲碳體組織結(jié)構(gòu)。

Control of this reaction, which arises due to the drastically different carbon solubility of austenite and ferrite, enables a wide range of properties to be achieved through heat treatment.控制這一由于奧氏體和鐵素體的碳溶解性完全不同而產(chǎn)生的反應(yīng)，使得通過熱處理能獲得很大范圍的特性。

To begin to understand these processes, consider a steel of the eutectoid composition, 0.77% carbon, being slow cooled along line x-x’ in

Fig.2.1.At the upper temperatures, only austenite is present, the 0.77% carbon being dissolved in solid solution with the iron.When the steel cools to 727℃(1341℉), several changes occur simultaneously.為了理解這些過程，考慮含碳量為0.77%的共析鋼，沿著圖2.1的x-x’線慢慢冷卻。在較高溫度時(shí)，只存在奧氏體，0.77%的碳溶解在鐵里形成固溶體。當(dāng)鋼冷卻到727℃(1341℉)時(shí)，將同時(shí)發(fā)生若干變化。

The iron wants to change from the FCC austenite structure to the BCC ferrite structure, but the ferrite can only contain 0.02% carbon in solid solution.鐵需要從面心立方體奧氏體結(jié)構(gòu)轉(zhuǎn)變?yōu)轶w心立方體鐵素體結(jié)構(gòu)，但是鐵素體只能容納固溶體狀態(tài)的0.02%的碳。

The rejected carbon forms the carbon-rich cementite intermetallic with composition Fe3C.In essence, the net reaction at the eutectoid is austenite 0.77%C→ferrite 0.02%C+cementite 6.67%C.被析出的碳與金屬化合物Fe3C形成富碳的滲碳體。本質(zhì)上，共析體的基本反應(yīng)是奧氏體0.77%的碳→鐵素體0.02%的碳+滲碳體6.67%的碳。

Since this chemical separation of the carbon component occurs entirely in the solid state, the resulting structure is a fine mechanical mixture of ferrite and cementite.Specimens prepared by polishing and etching in a weak solution of nitric acid and alcohol reveal the lamellar structure of

alternating plates that forms on slow cooling.由于這種碳成分的化學(xué)分離完全發(fā)生在固態(tài)中，產(chǎn)生的組織結(jié)構(gòu)是一種細(xì)致的鐵素體與滲碳體的機(jī)械混合物。通過打磨并在弱硝酸酒精溶液中蝕刻制備的樣本顯示出由緩慢冷卻形成的交互層狀的薄片結(jié)構(gòu)。

This structure is composed of two distinct phases, but has its own set of characteristic properties and goes by the name pearlite, because of its resemblance to mother-of-pearl at low magnification.這種結(jié)構(gòu)由兩種截然不同的狀態(tài)組成，但它本身具有一系列特性，且因與低倍數(shù)放大時(shí)的珠母層有類同之處而被稱為珠光體。

Steels having less than the eutectoid amount of carbon(less than 0.77%)are known as hypo-eutectoid steels.Consider now the transformation of such a material represented by cooling along line y-y’ in Fig.2.1.含碳量少于共析體(低于0.77%)的鋼稱為亞共析鋼?，F(xiàn)在來看這種材料沿著圖2.1中y-y’ 線冷卻的轉(zhuǎn)變情況。

At high temperatures, the material is entirely austenite, but upon cooling enters a region where the stable phases are ferrite and austenite.Tie-line and level-law calculations show that low-carbon ferrite nucleates and grows, leaving the remaining austenite richer in carbon.在較高溫度時(shí)，這種材料全部是奧氏體，但隨著冷卻就進(jìn)入到鐵素體和奧氏體穩(wěn)定狀態(tài)的區(qū)域。由截線及杠桿定律分析可知，低碳鐵素體成核并長(zhǎng)大，剩下含碳

量高的奧氏體。

At 727℃(1341℉), the austenite is of eutectoid composition(0.77% carbon)and further cooling transforms the remaining austenite to pearlite.The resulting structure is a mixture of primary or pro-eutectoid ferrite(ferrite that formed above the eutectoid reaction)and regions of pearlite.在727℃(1341℉)時(shí)，奧氏體為共析組成(含碳量0.77%)，再冷卻剩余的奧氏體就轉(zhuǎn)化為珠光體。作為結(jié)果的組織結(jié)構(gòu)是初步的共析鐵素體(在共析反應(yīng)前的鐵素體)和部分珠光體的混合物。

Hypereutectoid steels are steels that contain greater than the eutectoid amount of carbon.When such steel cools, as shown in z-z’ of Fig.2.1 the process is similar to the hypo-eutectoid case, except that the primary or pro-eutectoid phase is now cementite instead of ferrite.過共析鋼是含碳量大于共析量的鋼。當(dāng)這種鋼冷卻時(shí)，就像圖2.1的z-z’線所示，除了初步的共析狀態(tài)用滲碳體取代鐵素體外，其余類似亞共析鋼的情況。

As the carbon-rich phase forms, the remaining austenite decreases in carbon content, reaching the eutectoid composition at 727℃(1341℉).As before, any remaining austenite transforms to pearlite upon slow cooling through this temperature.隨著富碳部分的形成，剩余奧氏體含碳量減少，在727℃(1341℉)時(shí)達(dá)到共析組

織。就像以前說的一樣，當(dāng)緩慢冷卻到這溫度時(shí)所有剩余奧氏體轉(zhuǎn)化為珠光體。

It should be remembered that the transitions that have been described by the phase diagrams are for equilibrium conditions, which can be approximated by slow cooling.With slow heating, these transitions occur in the reverse manner.應(yīng)該記住由狀態(tài)圖描述的這種轉(zhuǎn)化只適合于通過緩慢冷卻的近似平衡條件。如果緩慢加熱，則以相反的方式發(fā)生這種轉(zhuǎn)化。

However, when alloys are cooled rapidly, entirely different results may be obtained, because sufficient time is not provided for the normal phase reactions to occur, in such cases, the phase diagram is no longer a useful tool for engineering analysis.然而，當(dāng)快速冷卻合金時(shí)，可能得到完全不同的結(jié)果。因?yàn)闆]有足夠的時(shí)間讓正常的狀態(tài)反應(yīng)發(fā)生，在這種情況下對(duì)工程分析而言狀態(tài)圖不再是有用的工具。

Hardening 淬火

Hardening is the process of heating a piece of steel to a temperature within or above its critical range and then cooling it rapidly.淬火就是把鋼件加熱到或超過它的臨界溫度范圍，然后使其快速冷卻的過程。If the carbon content of the steel is known, the proper temperature to which the steel should be heated may be obtained by reference to the iron-iron

carbide phase diagram.However, if the composition of the steel is unknown, a little preliminary experimentation may be necessary to determine the range.如果鋼的含碳量已知，鋼件合適的加熱溫度可參考鐵碳合金狀態(tài)圖得到。然而當(dāng)鋼的成分不知道時(shí)，則需做一些預(yù)備試驗(yàn)來確定其溫度范圍。

A good procedure to follow is to heat-quench a number of small specimens of the steel at various temperatures and observe the result, either by hardness testing or by microscopic examination.When the correct temperature is obtained, there will be a marked change in hardness and other properties.要遵循的合適步驟是將這種鋼的一些小試件加熱到不同的溫度后淬火，再通過硬度試驗(yàn)或顯微鏡檢查觀測(cè)結(jié)果。一旦獲得正確的溫度，硬度和其它性能都將有明顯的變化。

In any heat-treating operation the rate of heating is important.Heat flows from the exterior to the interior of steel at a definite rate.If the steel is heated too fast, the outside becomes hotter than the interior and uniform structure cannot be obtained.在任何熱處理作業(yè)中，加熱的速率都是重要的。熱量以一定的速率從鋼的外部傳導(dǎo)到內(nèi)部。如果鋼被加熱得太快，其外部比內(nèi)部熱就不能得到均勻的組織結(jié)構(gòu)。

If a piece is irregular in shape, a slow rate is all the more essential to eliminate warping and cracking.The heavier the section, the longer must be the heating time to achieve uniform results.如果工件形狀不規(guī)則，為了消除翹曲和開裂最根本的是加熱速率要緩慢。截面越厚，加熱的時(shí)間就要越長(zhǎng)才能達(dá)到均勻的結(jié)果。

Even after the correct temperature has been reached, the piece should be held at that temperature for a sufficient period of time to permit its thickest section to attain a uniform temperature.即使加熱到正確的溫度后，工件也應(yīng)在此溫度下保持足夠時(shí)間以讓其最厚截面達(dá)到相同溫度。

The hardness obtained from a given treatment depends on the quenching rate, the carbon content, and the work size.In alloy steels the kind and amount of alloying element influences only the hardenability(the ability of the workpiece to be hardened to depths)of the steel and does not affect the hardness except in unhardened or partially hardened steels.通過給定的熱處理所得到的硬度取決于淬火速率、含碳量和工件尺寸。除了非淬硬鋼或部分淬硬鋼外，合金鋼中合金元素的種類及含量?jī)H影響鋼的淬透性(工件被硬化到深層的能力)而不影響硬度。

Steel with low carbon content will not respond appreciably to hardening treatment.As the carbon content in steel increases up to around 0.60%, the possible hardness obtainable also increases.含碳量低的鋼對(duì)淬火處理沒有明顯的反應(yīng)。隨著鋼的含碳量增加到大約0.60%，可能得到的硬度也增加。

Above this point the hardness can be increased only slightly, because steels above the eutectoid point are made up entirely of pearlite and cementite in the annealed state.Pearlite responds best to heat-treating operations;and steel composed mostly of pearlite can be transformed into a hard steel.高于此點(diǎn)，由于超過共析點(diǎn)鋼完全由珠光體和退火狀態(tài)的滲碳體組成，硬度增加并不多。珠光體對(duì)熱處理作業(yè)響應(yīng)最好；基本由珠光體組成的鋼能轉(zhuǎn)化成硬質(zhì)鋼。

As the size of parts to be hardened increases, the surface hardness decreases somewhat even though all other conditions have remained the same.There is a limit to the rate of heat flow through steel.即使所有其它條件保持不變，隨著要淬火的零件尺寸的增加其表面硬度也會(huì)有所下降。熱量在鋼中的傳導(dǎo)速率是有限的。

No matter how cool the quenching medium may be, if the heat inside a large piece cannot escape faster than a certain critical rate, there is a definite limit to the inside hardness.However, brine or water quenching is capable of rapidly bringing the surface of the quenched part to its own temperature and maintaining it at or close to this temperature.無論淬火介質(zhì)怎么冷，如果在大工件中的熱量不能比特定的臨界速率更快散發(fā)，那它內(nèi)部硬度就會(huì)受到明確限制。然而鹽水或水淬火能夠?qū)⒈淮懔慵谋砻嫜杆倮鋮s至本身溫度并將其保持或接近此溫度。

Under these circumstances there would always be some finite depth of surface hardening regardless of size.This is not true in oil quenching, when the surface temperature may be high during the critical stages of quenching.在這種情況下不管零件尺寸如何，其表面總歸有一定深度被硬化。但油淬情況就不是如此，因?yàn)橛痛銜r(shí)在淬火臨界階段零件表面的溫度可能仍然很高。

Tempering 回火

Steel that has been hardened by rapid quenching is brittle and not suitable for most uses.By tempering or drawing, the hardness and brittleness may be reduced to the desired point for service conditions．

快速淬火硬化的鋼是硬而易碎的，不適合大多數(shù)場(chǎng)合使用。通過回火，硬度和脆性可以降低到使用條件所需要的程度。

As these properties are reduced there is also a decrease in tensile strength and an increase in the ductility and toughness of the steel.The operation consists of reheating quench-hardened steel to some temperature below the critical range followed by any rate of cooling.隨著這些性能的降低，拉伸強(qiáng)度也降低而鋼的延展性和韌性則會(huì)提高。回火作業(yè)包括將淬硬鋼重新加熱到低于臨界范圍的某一溫度然后以任意速率冷卻。

Although this process softens steel, it differs considerably from annealing in that the process lends itself to close control of the physical properties and in most cases does not soften the steel to the extent that

annealing would.The final structure obtained from tempering a fully hardened steel is called tempered martensite.雖然這過程使鋼軟化，但它與退火是大不相同的，因?yàn)榛鼗疬m合于嚴(yán)格控制物理性能并在大多數(shù)情況下不會(huì)把鋼軟化到退火那種程度?；鼗鹜耆阌蹭摰玫降淖罱K組織結(jié)構(gòu)被稱為回火馬氏體。

Tempering is possible because of the instability of the martensite, the principal constituent of hardened steel.Low-temperature draws, from 300℉ to 400℉(150℃~205℃), do not cause much decrease in hardness and are used principally to relieve internal strains.由于馬氏體這一淬硬鋼主要成分的不穩(wěn)定性，使得回火成為可能。低溫回火，300℉到400℉(150℃~205℃)，不會(huì)引起硬度下降很多，主要用于減少內(nèi)部應(yīng)變。

As the tempering temperatures are increased, the breakdown of the martensite takes place at a faster rate, and at about 600℉(315℃)the change to a structure called tempered martensite is very rapid.The tempering operation may be described as one of precipitation and agglomeration or coalescence of cementite.隨著回火溫度的提高，馬氏體以較快的速率分解，并在大約600℉(315℃)迅速轉(zhuǎn)變?yōu)楸环Q為回火馬氏體的結(jié)構(gòu)。回火作業(yè)可以描述為滲碳體析出和凝聚或聚結(jié)的過程。

A substantial precipitation of cementite begins at 600℉(315℃), which

produces a decrease in hardness.Increasing the temperature causes coalescence of the carbides with continued decrease in hardness.滲碳體的大量析出開始于600℉(315℃)，這使硬度下降。溫度的上升會(huì)使碳化物聚結(jié)而硬度繼續(xù)降低。

In the process of tempering, some consideration should be given to time as well as to temperature.Although most of the softening action occurs in the first few minutes after the temperature is reached, there is some additional reduction in hardness if the temperature is maintained for a prolonged time.在回火過程中，不但要考慮溫度而且要考慮時(shí)間。雖然大多數(shù)軟化作用發(fā)生在達(dá)到所需溫度后的最初幾分鐘，但如果此溫度維持一段延長(zhǎng)時(shí)間，仍會(huì)有些額外的硬度下降。

Usual practice is to heat the steel to the desired temperature and hold it there only long enough to have it uniformly heated.通常的做法是將鋼加熱到所需溫度并且僅保溫到正好使其均勻受熱。

Two special processes using interrupted quenching are a form of tempering.In both, the hardened steel is quenched in a salt bath held at a selected lower temperature before being allowed to cool.These processes, known as austempering and martempering, result in products having certain desirable physical properties.兩種采用中斷淬火的特殊工藝也是回火的形式。這兩種工藝中，淬硬鋼在其被允許冷卻前先在一選定的較低溫度鹽浴淬火。這兩種分別被稱為奧氏體回火和馬氏體回火的工藝，能使產(chǎn)品具有特定所需的物理性能。

Annealing 退火

The primary purpose of annealing is to soften hard steel so that it may be machined or cold worked.退火的主要目的是使堅(jiān)硬的鋼軟化以便機(jī)加工或冷作。

This is usually accomplished by heating the steel too slightly above the critical temperature, holding it there until the temperature of the piece is uniform throughout, and then cooling at a slowly controlled rate so that the temperature of the surface and that of the center of the piece are approximately the same.通常是非常緩慢地將鋼加熱到臨界溫度以上，并將其在此溫度下保持到工件全部均勻受熱，然后以受控的速率慢慢地冷卻，這樣使得工件表面和內(nèi)部的溫度近似相同。

This process is known as full annealing because it wipes out all trace of previous structure, refines the crystalline structure, and softens the metal.Annealing also relieves internal stresses previously set up in the metal.這過程被稱為完全退火，因?yàn)樗コ艘郧敖M織結(jié)構(gòu)的所有痕跡、細(xì)化晶粒并

軟化金屬。退火也釋放了先前在金屬中的內(nèi)應(yīng)力。

The temperature to which a given steel should be heated in annealing depends on its composition;for carbon steels it can be obtained readily from the partial iron-iron carbide equilibrium diagram.When the annealing temperature has been reached, the steel should be held there until it is uniform throughout.給定的鋼其退火溫度取決于它的成分；對(duì)碳鋼而言可容易地從局部的鐵碳合金平衡圖得到。達(dá)到退火溫度后，鋼應(yīng)當(dāng)保持在此溫度等到全部均勻受熱。

This usually takes about 45min for each inch(25mm)of thickness of the largest section.For maximum softness and ductility the cooling rate should be very slow, such as allowing the parts to cool down with the furnace.The higher the carbon content, the slower this rate must be.加熱時(shí)間一般以工件的最大截面厚度計(jì)每英寸(25mm)大約需45min。為了得到最大柔軟性和延展性冷卻速率應(yīng)該很慢，比如讓零件與爐子一起冷下來。含碳量越高，冷卻的速率必須越慢。

The heating rate should be consistent with the size and uniformity of sections, so that the entire part is brought up to temperature as uniformly as possible.加熱的速率也應(yīng)與截面的尺寸及均勻程度相協(xié)調(diào)，這樣才能使整個(gè)零件盡可能均勻地加熱。

Normalizing and Spheroidizing 正火和球化

The process of normalizing consists of heating the steel about 50℉ to 100℉(10℃~40℃)above the upper critical range and cooling in still air to room temperature.正火處理包括先將鋼加熱到高于上臨界區(qū)50℉到100℉(10℃~40℃)然后在靜止的空氣中冷卻到室溫。

This process is principally used with low-and medium-carbon steels as well as alloy steels to make the grain structure more uniform, to relieve internal stresses, or to achieve desired results in physical properties.Most commercial steels are normalized after being rolled or cast.退火主要用于低碳鋼、中碳鋼及合金鋼，使晶粒結(jié)構(gòu)更均勻、釋放內(nèi)應(yīng)力或獲得所需的物理特性。大多數(shù)商業(yè)鋼材在軋制或鑄造后都要退火。

Spheroidizing is the process of producing a structure in which the cementite is in a spheroidal distribution.If steel is heated slowly to a temperature just below the critical range and held there for a prolonged period of time, this structure will be obtained.球化是使?jié)B碳體產(chǎn)生成類似球狀分布結(jié)構(gòu)的工藝。如果把鋼緩慢加熱到恰好低于臨界溫度并且保持較長(zhǎng)一段時(shí)間，就能得到這種組織結(jié)構(gòu)。

The globular structure obtained gives improved machinability to the steel.This treatment is particularly useful for hypereutectoid steels that must be machined.所獲得的球狀結(jié)構(gòu)改善了鋼的可切削性。此處理方法對(duì)必須機(jī)加工的過共析鋼特別有用。

Surface Hardening 表面硬化 Carburizing The oldest known method of producing a hard surface on steel is case hardening or carburizing.Iron at temperatures close to and above its critical temperature has an affinity for carbon.滲碳

最早的硬化鋼表面的方法是表面淬火或滲碳。鐵在靠近并高于其臨界溫度時(shí)對(duì)碳具有親合力。

The carbon is absorbed into the metal to form a solid solution with iron and converts the outer surface into high-carbon steel.The carbon is gradually diffused to the interior of the part.The depth of the case depends on the time and temperature of the treatment.碳被吸收進(jìn)金屬與鐵形成固溶體使外表面轉(zhuǎn)變成高碳鋼。碳逐漸擴(kuò)散到零件內(nèi)

部。滲碳層的深度取決于熱處理的時(shí)間和溫度。

Pack carburizing consists of placing the parts to be treated in a closed container with some carbonaceous material such as charcoal or coke.It is a long process and used to produce fairly thick cases of from 0.03 to 0.16 in.(0.76~4.06mm)in depth.固體滲碳的方法是將要處理的零件與木炭或焦炭這些含碳的材料一起放入密閉容器。這是一個(gè)較長(zhǎng)的過程，用于產(chǎn)生深度為0.03到0.16 英寸(0.76~4.06mm)這么厚的硬化層。

Steel for carburizing is usually a low-carbon steel of about 0.15% carbon that would not in itself responds appreciably to heat treatment.In the course of the process the outer layer is converted into high-carbon steel with a content ranging from 0.9% to 1.2% carbon.用于滲碳的一般是含碳量約為0.15%、本身不太適合熱處理的低碳鋼。在處理過程中外層轉(zhuǎn)化為含碳量從0.9%到1.2%的高碳鋼。

A steel with varying carbon content and, consequently, different critical temperatures requires a special heat treatment.含碳量變化的鋼具有不同的臨界溫度，因此需要特殊的熱處理。

Because there is some grain growth in the steel during the prolonged carburizing treatment, the work should be heated to the critical temperature of the core and then cooled, thus refining the core structure.The steel

should then be reheated to a point above the transformation range of the case and quenched to produce a hard, fine structure.由于在較長(zhǎng)的滲碳過程中鋼內(nèi)部會(huì)有些晶粒生長(zhǎng)，所以工件應(yīng)該加熱到核心部分的臨界溫度再冷卻以細(xì)化核心部分的組織結(jié)構(gòu)。然后重新加熱到高于外層轉(zhuǎn)變溫度再淬火以生成堅(jiān)硬、細(xì)致的組織結(jié)構(gòu)。

The lower heat-treating temperature of the case results from the fact that hypereutectoid steels are normally austenitized for hardening just above the lower critical point.A third tempering treatment may be used to reduce strains.由于恰好高于低臨界溫度通常使過共析鋼奧氏體化而硬化，所以對(duì)外層采用較低的熱處理溫度。第三次回火處理可用于減少應(yīng)變。

Carbonitriding Carbonitriding, sometimes known as dry cyaniding or nicarbing, is a case-hardening process in which the steel is held at a temperature above the critical range in a gaseous atmosphere from which it absorbs carbon and nitrogen.碳氮共滲

碳氮共滲，有時(shí)也稱為干法氰化或滲碳氮化，是一種表面硬化工藝。通過把鋼放在高于臨界溫度的氣體中，讓它吸收碳和氮。

Any carbon-rich gas with ammonia can be used.The wear-resistant case produced ranges from 0.003 to 0.030 inch(0.08~ 0.76mm)in thickness.An advantage of carbonitriding is that the hardenability of the case is significantly increased when nitrogen is added, permitting the use of low-cost steels.可以使用任何富碳?xì)怏w加氨氣，能生成厚度從0.003到0.030英寸(0.08~ 0.76mm)的耐磨外層。碳氮共滲的優(yōu)點(diǎn)之一是加入氮后外層的淬透性極大增加，為使用低價(jià)鋼提供條件。

Cyaniding Cyaniding, or liquid carbonitriding as it is sometimes called, is also a process that combines the absorption of carbon and nitrogen to obtain surface hardness in low-carbon steels that do not respond to ordinary heat treatment.氰化

氰化，有時(shí)稱為液體碳氮共滲，也是一種結(jié)合了吸收碳和氮來獲得表面硬度的工藝，它主要用于不適合通常熱處理的低碳鋼。

The part to be case hardened is immersed in a bath of fused sodium cyanide salts at a temperature slightly above the Ac1 range, the duration of soaking depending on the depth of the case.The part is then quenched in water or oil to obtain a hard surface.35

需表面硬化的零件浸沒在略高于Ac1溫度熔化的氰化鈉鹽溶液中，浸泡的持續(xù)時(shí)間取決于硬化層的深度。然后將零件在水或油中淬火。

Case depths of 0.005 to 0.015in.(0.13~0.38mm)may be readily obtained by this process.Cyaniding is used principally for the treatment of small parts.通過這樣處理可以容易地獲得0.005到0.015英寸(0.13~0.38mm)的硬化深度。氰化主要用于處理小零件。

Nitriding Nitriding is somewhat similar to ordinary case hardening, but it uses a different material and treatment to create the hard surface constituents.滲氮

滲氮有些類似普通表面硬化，但它采用不同的材料和處理方法來產(chǎn)生堅(jiān)硬表面成分。

In this process the metal is heated to a temperature of around 950℉(510℃)and held there for a period of time in contact with ammonia gas.Nitrogen from the gas is introduced into the steel, forming very hard nitrides that are finely dispersed through the surface metal.這種工藝中金屬加熱到約950℉(510℃)，然后與氨氣接觸一段時(shí)間。氨氣中的氮進(jìn)入鋼內(nèi)，形成細(xì)微分布于金屬表面又十分堅(jiān)固的氮化物。

Nitrogen has greater hardening ability with certain elements than with others, hence, special nitriding alloy steels have been developed.氮與某些元素的硬化能力比其它元素大，因此開發(fā)了專用的滲氮合金鋼。Aluminum in the range of 1% to 1.5% has proved to be especially suitable in steel, in that it combines with the gas to form a very stable and hard constituent.The temperature of heating ranges from 925℉ to 1,050℉(495℃~565℃).在鋼中含鋁1%到1.5%被證明特別合適，它能與氨氣結(jié)合形成很穩(wěn)定堅(jiān)固的成分。其加熱溫度范圍為925℉到1,050℉(495℃~565℃)。

Liquid nitriding utilizes molten cyanide salts and, as in gas nitriding, the temperature is held below the transformation range.Liquid nitriding adds more nitrogen and less carbon than either cyaniding or carburizing in cyanide baths.液體滲氮利用熔化的氰化物鹽，就像氣體滲氮，溫度保持在低于轉(zhuǎn)化范圍內(nèi)。液體滲氮時(shí)在氰化物溶液中加入比氰化及滲碳都較多的氮和較少的碳。

Case thickness of 0.001 to 0.012in.(0.03~0.30mm)is obtained, whereas for gas nitriding the case may be as thick as 0.025 in.(0.64mm).In general the uses of the two-nitriding processes are similar.液體滲氮可以獲得厚度為0.001到0.012英寸(0.03~0.30mm)的硬化層，然而氣體滲氮?jiǎng)t能獲得厚0.025英寸(0.64mm)的硬化層。一般而言兩種滲氮方法的用途是類

似的。

Nitriding develops extreme hardness in the surface of steel.This hardness ranges from 900 to 1,100 Brinell, which is considerably higher than that obtained by ordinary case hardening.滲氮在鋼表面獲得遠(yuǎn)遠(yuǎn)超出正常標(biāo)準(zhǔn)的硬度。其硬度范圍為900到1,100布氏硬度，這遠(yuǎn)高于普通表面硬化所獲得的硬度。

Nitriding steels, by virtue of their alloying content, are stronger than ordinary steels and respond readily to heat treatment.It is recommended that these steels be machined and heat-treated before nitriding, because there is no scale or further work necessary after this process.由于滲氮鋼的合金比例，它們比普通鋼更強(qiáng)，也容易熱處理。建議對(duì)這種鋼在滲氮前先機(jī)加工和熱處理，因?yàn)闈B氮后沒有剝落并不需要更多的加工。

Fortunately, the interior structure and properties are not affected appreciably by the nitriding treatment and, because no quenching is necessary, there is little tendency to warp, develop cracks, or change condition in any way.The surface effectively resists corrosive action of water, saltwater spray, alkalies, crude oil, and natural gas.值得慶幸的是由于滲氮處理一點(diǎn)都不影響內(nèi)部結(jié)構(gòu)和性能，也無需淬火，所以幾乎沒有任何產(chǎn)生翹曲、裂縫及變化條件的趨勢(shì)。這種表面能有效地抵御水、鹽霧、堿、原油和天然氣的腐蝕反應(yīng)。

Casting is a manufacturing process in which molten metal is poured or injected and allowed to solidify in a suitably shaped mold cavity.During or after cooling, the cast part is removed from the mold and then processed for delivery.鑄造是一種將熔化的金屬倒入或注入合適的鑄模腔并且在其中固化的制造工藝。在冷卻期間或冷卻后，把鑄件從鑄模中取出，然后進(jìn)行交付。

Casting processes and cast-material technologies vary from simple to highly complex.Material and process selection depends on the part’s complexity and function, the product’s quality specifications, and the projected cost level.鑄造工藝和鑄造材料技術(shù)從簡(jiǎn)單到高度復(fù)雜變化很大。材料和工藝的選擇取決于零件的復(fù)雜性和功能、產(chǎn)品的質(zhì)量要求以及成本預(yù)算水平。

Castings are parts that are made close to their final dimensions by a casting process.With a history dating back 6,000 years, the various casting processes are in a state of continuous refinement and evolution as technological advances are being made.通過鑄造加工，鑄件可以做成很接近它們的最終尺寸?；厮?,000年歷史，各種各樣的鑄造工藝就如同科技進(jìn)步一樣處于一個(gè)不斷改進(jìn)和發(fā)展的狀態(tài)。

Sand Casting 砂型鑄造

Sand casting is used to make large parts(typically iron, but also bronze，39

brass, aluminum).Molten metal is poured into a mold cavity formed out of sand(natural or synthetic).砂型鑄造用于制造大型零件(具有代表性是鐵，除此之外還有青銅、黃銅和鋁)。將熔化的金屬倒入由型砂(天然的或人造的)做成鑄模腔。

The processes of sand casting are discussed in this section, including patterns, sprues and runners, design considerations, and casting allowance.本節(jié)討論砂型鑄造工藝，包括型模、澆注口、澆道、設(shè)計(jì)考慮因素及鑄造余量。The cavity in the sand is formed by using a pattern(an approximate duplicate of the real part), which are typically made out of wood, sometimes metal.The cavity is contained in an aggregate housed in a box called the flask.砂型里的型腔是采用型模(真實(shí)零件的近似復(fù)制品)構(gòu)成的，型模一般為木制，有時(shí)也用金屬制造。型腔整個(gè)包含在一個(gè)被放入稱為砂箱的箱子里的組合體內(nèi)。

Core is a sand shape inserted into the mold to produce the internal features of the part such as holes or internal passages.Cores are placed in the cavity to form holes of the desired shapes.Core print is the region added to the pattern, core, or mold that is used to locate and support the core within the mold.砂芯是插入鑄模的砂型，用于生成諸如孔或內(nèi)通道之類的內(nèi)部特征。砂芯安放在型腔里形成所需形狀的孔洞。砂芯座是加在型模、砂芯或鑄模上的特定區(qū)域，用

來在鑄模內(nèi)部定位和支撐砂芯。

A riser is an extra void created in the mold to contain excessive molten material.The purpose of this is to feed the molten metal to the mold cavity as the molten metal solidifies and shrinks, and thereby prevents voids in the main casting.冒口是在鑄模內(nèi)部增加的額外空間，用于容納過多的熔化金屬。其目的是當(dāng)熔化金屬凝固和收縮時(shí)往型腔里補(bǔ)充熔化金屬，從而防止在主鑄件中產(chǎn)生孔隙。

In a two-part mold, which is typical of sand castings, the upper half, including the top half of the pattern, flask, and core is called cope and the lower half is called drag, as shown in Fig.3.1.The parting line or the parting surface is line or surface that separates the cope and drag.在典型砂型鑄造的兩箱鑄模中，上半部分(包括型模頂半部、砂箱和砂芯)稱為上型箱，下半部分稱為下型箱，見圖3.1所示。分型線或分型面是分離上下型箱的線或面。

The drag is first filled partially with sand, and the core print, the cores, and the gating system are placed near the parting line.The cope is then assembled to the drag, and the sand is poured on the cope half, covering the pattern, core and the gating system.首先往下型箱里部分地填入型砂和砂芯座、砂芯，并在靠近分型線處放置澆注系統(tǒng)。然后將上型箱與下型箱裝配在一起，再把型砂倒入上型箱蓋住型模、砂芯和

澆注系統(tǒng)。

The sand is compacted by vibration and mechanical means.Next, the cope is removed from the drag, and the pattern is carefully removed.The object is to remove the pattern without breaking the mold cavity.型砂通過振動(dòng)和機(jī)械方法壓實(shí)。然后從下型箱上撤掉上型箱，小心翼翼地取出型模。其目的是取出型模而不破壞型腔。

This is facilitated by designing a draft, a slight angular offset from the vertical to the vertical surfaces of the pattern.This is usually a minimum of 1.5mm(0.060in.), whichever is greater.The rougher the surface of the pattern, the more the draft to be provided.通過設(shè)計(jì)拔模斜度—型模垂直相交表面的微小角度偏移量—來使取出型模變得容易。拔模斜度最小一般為1.5mm(0.060in.)，只能比此大。型模表面越粗糙，則拔模斜度應(yīng)越大。

The molten material is poured into the pouring cup, which is part of the gating system that supplies the molten material to the mold cavity.熔化的金屬?gòu)臐沧⒈⑷胄颓?，澆注杯是澆注系統(tǒng)向型腔提供熔化金屬的部分。The vertical part of the gating system connected to the pouring cup is the sprue, and the horizontal portion is called the runners and finally to the multiple points where it is introduced to the mold cavity called the gates.42

將澆注系統(tǒng)的垂直部分與澆注杯連接的是澆注口，澆注系統(tǒng)的水平部分稱為澆道，最后到多點(diǎn)把熔化金屬導(dǎo)入型腔的稱為閘道。

Additionally there are extensions to the gating system called vents that provide the path for the built-up gases and the displaced air to vent to the atmosphere.除此之外，還有稱為排放口的澆注系統(tǒng)延長(zhǎng)段，它為合成氣體和置換空氣排放到大氣提供通道。

The cavity is usually made oversize to allow for the metal contraction as it cools down to room temperature.This is achieved by making the pattern oversize.To account for shrinking, the pattern must be made oversize by these factors on the average.These are linear factors and apply in each direction.型腔通常大于所需尺寸以允許在金屬冷卻到室溫時(shí)收縮。這通過把型模做得大于所需尺寸來達(dá)到。為解決收縮效應(yīng)，一般而言型模做得比所需尺寸大，必須考慮線性因素并作用于各個(gè)方向。

These shrinkage allowances are only approximate, because the exact allowance is determined by the shape and size of the casting.In addition, different parts of the casting might require different shrinkage allowances.收縮余量?jī)H僅是近似的，因?yàn)闇?zhǔn)確的余量是由鑄件的形狀和尺寸決定的。另外，鑄件的不同部分也可能需要不同的收縮余量。

Sand castings generally have a rough surface sometimes with surface impurities, and surface variations.A machining(finish)allowance is made for this type of defect.砂型鑄件一般表面粗糙，有時(shí)還帶有表面雜質(zhì)和表面變異。對(duì)這類缺陷采用機(jī)加工(最后一道工序)的余量。

In general, typical stages of sand casting operation include(as shown in Fig.3.2): 1.Patterns are made.These will be the shape used to form the cavity in the sand.一般而言，砂型鑄造作業(yè)的典型階段包括(如圖3.2所示)： 1.制作型模。做成用于在型砂中形成型腔的形狀。

2.Cores may also be made at this time.These cores are made of bonded sand that will be broken out of the cast part after it is complete.3.Sand is mulled(mixed)thoroughly with additives such as bentonite to increase bonding and overall strength.2.同時(shí)還要制作砂芯。這些砂芯用粘結(jié)砂做成，等鑄件完成后將被打碎取出。3.型砂與膨潤(rùn)土之類的添加劑充分地混合以增強(qiáng)連接及整體強(qiáng)度。

4.Sand is formed about the patterns, and gates, runners, risers, vents

and pouring cups are added as needed.A compaction stage is typically used to ensure good coverage and solid molds.4.型砂在型模周圍成形，并根據(jù)需要安放閘道、澆道、冒口、排放口和澆注杯等。通常要采取壓緊步驟來保證良好的覆蓋和堅(jiān)固的鑄型。

Cores may also be added to make concave or internal features for the cast part.Alignment pins may also be used for mating the molds later.Chills may be added to cool large masses faster.安放砂芯來制成鑄件的凹形結(jié)構(gòu)或內(nèi)部特征。為了以后鑄模匹配還要用到定位銷。對(duì)大質(zhì)量鑄件可能需要加入冷卻物來使其較快冷卻。

5.The patterns are removed, and the molds may be put through a baking stage to increase strength.6.Mold halves are mated and prepared for pouring metal.5.取走型模，將鑄模烘焙以增加強(qiáng)度。6.匹配上下鑄模，做好澆鑄金屬的準(zhǔn)備。

7.Metal is preheated in a furnace or crucible until is above the liquidus temperature in a suitable range(we don’t want the metal solidifying before the pour is complete).The exact temperature may be closely controlled depending upon the application.7.金屬在熔爐或坩堝中預(yù)熱到高于液化溫度的一個(gè)合適范圍內(nèi)(不希望金屬在

澆鑄完成前凝固)。確切的溫度要根據(jù)應(yīng)用場(chǎng)合嚴(yán)格控制。

Degassing, and other treatment processes may be done at this time, such as removal of impurities(i.e.slag).Some portion of this metal may be remelted scrap from previously cast parts—10% is reasonable.在此期間還要進(jìn)行排氣和其它處理步驟，例如去除雜質(zhì)(即熔渣)?？梢约尤胍欢吭仁沁@種金屬鑄件的廢料再融化—10%是適當(dāng)?shù)摹?/p>

8.The metal is poured slowly, but continuously into the mold until the mold is full.9.As the molten metal cools(minutes to days), the metal will shrink and the volume will decrease.During this time molten metal may backflow from the molten risers to feed the part and maintain the same shape.8.將金屬緩慢而連續(xù)地注滿型模。

9.隨著熔化金屬的冷卻(幾分鐘到幾天)，金屬收縮體積減小。在此期間熔化金屬可能從冒口回流供給零件以保持其形狀不變。

10.Once the part starts to solidify small dendrites of solid material form in the part.During this time metal properties are being determined, and internal stresses are being generated.If a part is allowed to cool slowly enough at a constant rate then the final part will be relatively homogenous and stress free.46

10.在零件開始凝固其內(nèi)部形成固態(tài)金屬的小型樹枝狀結(jié)晶期間金屬性能被確定，同時(shí)也產(chǎn)生了內(nèi)應(yīng)力。如果零件以恒定速率冷卻得足夠緩慢，最終零件將相對(duì)均質(zhì)并釋放內(nèi)應(yīng)力。

11.Once the part has completely solidified below the eutectic point it may be removed with no concern for final metal properties.At this point the sand is simply broken up, and the part removed.At this point the surface will have a quantity of sand adhering to the surface, and solid cores inside.11.一旦零件在共析點(diǎn)以下完全凝固，可以不考慮金屬的最后性能而將其取出。這時(shí)可以簡(jiǎn)單地打碎砂型并取出零件，但零件表面會(huì)有大量型砂粘附著，內(nèi)部還有實(shí)心的砂芯。

12.A bulk of the remaining sand and cores can be removed by mechanically striking the part.Other options are to use a vibrating table, sand/shot blaster, hand labor, etc.12.大量的剩余型砂和砂芯要通過機(jī)械敲擊零件來去除。其它的選擇還有采用振動(dòng)臺(tái)、噴砂/噴丸機(jī)、手工作業(yè)等等。

13.The final part is cut off the runner gate system, and is near final shape using cutters, torches, etc.Grinding operations are used to remove any remaining bulk.14.The part is taken down to final shape using machining operations.And cleaning operations may be used to remove oxides, etc.47

13.最后零件要用刀具、噴槍等切掉澆道閘道系統(tǒng)，這樣就接近最終形狀了。再用磨削作業(yè)去除多余的部分。

14.通過機(jī)加工將零件切削到最終形狀。可能還要用清洗作業(yè)去除氧化物等。Investment casting 熔模鑄造

Investment casting is also known as the lost wax process.This process is one of the oldest manufacturing processes.The Egyptians used it in the time of the Pharaohs to make gold jewelry(hence the name Investment)some 5,000 years ago.熔模鑄造也稱為失蠟加工。這是最古老的制造工藝之一。大約在5,000年前的法老王時(shí)代，埃及人就用它制造黃金飾品(因此而得名投資)。

Intricate shapes can be made with high accuracy.In addition, metals that are hard to machine or fabricate are good candidates for this process.It can be used to make parts that cannot be produced by normal manufacturing techniques, such as turbine blades that have complex shapes, or airplane parts that have to withstand high temperatures.復(fù)雜的形狀能被高精度地制造。另外較難機(jī)加工或制作的金屬都能用此工藝。它還能用于生產(chǎn)一般制造技術(shù)無法生產(chǎn)的零件，例如有復(fù)雜形狀的渦輪葉片或必須耐得住高溫的飛機(jī)零件。

The mold is made by making a pattern using wax or some other material that can be melted away.This wax pattern is dipped in refractory slurry, which coats the wax pattern and forms a skin.This is dried and the process of dipping in the slurry and drying is repeated until a robust thickness is achieved.制作鑄型的型模采用石蠟或其它一些能被融化掉的材料做成。石蠟型模浸泡在耐熱漿里，讓它覆蓋型模并形成外殼，然后使其變干。重復(fù)這個(gè)浸泡、變干的過程直至獲得足夠的厚度。

After this, the entire pattern is placed in an oven and the wax is melted away.This leads to a mold that can be filled with the molten metal.Because the mold is formed around a one-piece pattern(which does not have to be pulled out from the mold as in a traditional sand casting process), very intricate parts and undercuts can be made.完成后把整個(gè)型模放在烤箱里融化石蠟。這樣就做成了能填充熔化金屬的鑄型。由于這種鑄型是環(huán)繞整塊型模形成的(無需像傳統(tǒng)的砂型鑄造工藝那樣拔模)，能制作十分復(fù)雜的零件和浮雕。

The wax pattern itself is made by duplicating using a stereo lithography or similar model—which has been fabricated using a computer solid model master.石蠟型模本身能用立體制版或類似的模型復(fù)制—這可以采用計(jì)算機(jī)立體模型原

版制作。

The materials used for the slurry are a mixture of plaster, a binder and powdered silica, a refractory, for low temperature melts.For higher temperature melts, sillimanite or alumina-silicate is used as a refractory, and silica is used as a binder.對(duì)較低熔化溫度而言，用于耐熱漿的材料是石膏作粘合劑和用粉末狀硅石作耐溫材料的混合物。對(duì)較高熔化溫度而言，則采用硅線石或氧化鋁硅酸鹽作耐溫材料、無水硅酸作粘合劑。

Depending on the fineness of the finish desired additional coatings of sillimanite and ethyl silicate may be applied.The mold thus produced can be used directly for light castings, or be reinforced by placing it in a larger container and reinforcing it more slurry.根據(jù)最后所需光潔度也可采用硅線石和乙烷基硅酸鹽。這樣生成的鑄?？芍苯佑糜诒”阼T件或通過將其放在較大容器內(nèi)用更多耐熱漿加強(qiáng)。

Just before the pour, the mold is pre-heated to about 1,000℃(1,832℉)to remove any residues of wax, harden the binder.The pour in the pre-heated mold also ensures that the mold will fill completely.在正要澆鑄之前，將型模預(yù)熱到約1,000℃(1,832℉)以去除剩余石蠟、硬化粘合劑。在預(yù)熱的型模中澆鑄也能保證型模完全充滿。

Pouring can be done using gravity, pressure or vacuum conditions.50

第三篇：專業(yè)英語(yǔ)感受 中英文對(duì)照

電力工程專業(yè)英語(yǔ)

Power engineering professional English

專業(yè)英語(yǔ)學(xué)習(xí)體會(huì)

英語(yǔ)作為一門重要的學(xué)科，正在由于科技的飛速發(fā)展、信息全球化、社會(huì)化的日趨接近以及國(guó)際語(yǔ)言的特殊身份而身價(jià)倍增，成為了跨入二十一世紀(jì)所必備的三張通行證之一。English as an important subject, is due to the rapid development of science and technology, the information globalization, the increasingly close to social special identity and values as well as the international language, has become the essential coming 21-st century one of the three pass.新的一代是否具備這張通行證將會(huì)直接影響祖國(guó)明天的輝煌。A new generation have this pass will directly affect the glory of the motherland tomorrow.從這個(gè)意義上說，通過學(xué)習(xí)英語(yǔ)來培養(yǎng)學(xué)生積極學(xué)習(xí)、主動(dòng)探取的主體性品質(zhì)以適應(yīng)現(xiàn)代化社會(huì)的發(fā)展顯得尤為必要。In this sense, through learning English to cultivate students' positive learning, active agent take the subjective quality of the development of the society it is necessary to adapt to the modernization尤其是我們當(dāng)代研究生，掌握好英語(yǔ)，尤其是自己專業(yè)方面的外語(yǔ)，無論是對(duì)自己完成學(xué)業(yè)，還是未來找工作都有很重要的作用。Especially our contemporary graduate student, mastering English well, especially in foreign languages, in their major area of both finished school on their own, or in the future job has a very important role.通過這學(xué)期專業(yè)英語(yǔ)的學(xué)習(xí)，我學(xué)到了很多東西，更重要的是知道了學(xué)習(xí)專業(yè)英語(yǔ)的重要性。Through the study of professional English this term, I learned a lot of things, more important is to know the importance of learning English.首先，雖然我們以前已經(jīng)學(xué)了很長(zhǎng)時(shí)間的英語(yǔ)，但學(xué)的還遠(yuǎn)遠(yuǎn)不夠。First of all, although we had for a long time to learn English, but learning is not enough因?yàn)槲覀儗W(xué)的英語(yǔ)基本上都是一些基礎(chǔ)的、常用的表達(dá)，對(duì)于自己專業(yè)領(lǐng)域的一些詞匯怎么表達(dá)還不了解。Because we learn English is essentially the expression of some basic and commonly used, some words how to say about their professional field is not understood.所以，學(xué)習(xí)專業(yè)英語(yǔ)是很必要的。尤其是隨著地理學(xué)科的不斷發(fā)展和新技術(shù)的廣泛應(yīng)用，對(duì)地理專業(yè)學(xué)生來說學(xué)習(xí)電力專業(yè)英語(yǔ)是必不可少的，也是吸取國(guó)外先進(jìn)知識(shí)，進(jìn)行國(guó)內(nèi)外學(xué)術(shù)交流的基礎(chǔ)。So, learning English is very necessary.Especially with the continuous development of geography and the wide application of new technology for geography majors to learn professional English is indispensable, and absorbing the foreign advanced knowledge, on the basis of domestic and international academic exchanges 因?yàn)橛⒄Z(yǔ)作為世界上應(yīng)用最廣泛的一門語(yǔ)言，許多專業(yè)領(lǐng)域的文獻(xiàn)和資料都是用英文書寫的。Because English is the world the most widely used language in the world, many professional in the field of literature and data are written in English.如果我們想了解我們專業(yè)領(lǐng)域的最新研究成果，我們就必須學(xué)好專業(yè)英語(yǔ)，這樣才能讀懂自己專業(yè)方面的英文文獻(xiàn)，使自己的研究跟上時(shí)代的步伐。

If we want to know we are professional in the field of the latest research results, we must learn English well, so you can read English literature in their

major area of, make oneself of the study to keep up with the pace of The Times.其次，隨著中國(guó)國(guó)門的不斷開放，我們與國(guó)外相關(guān)專家學(xué)者交流的機(jī)會(huì)將不斷增多，這就需要我們掌握好英語(yǔ)——這張世界的通行證。Second, as China's doors open, us the opportunity to communicate with foreign related experts and scholars will continuously increase, this needs us to master English well, the world pass.如果我們不能很好的掌握自己研究領(lǐng)域的英文表達(dá)，那么在與國(guó)外專家交流時(shí)就會(huì)遇到這樣那樣問題，影響我們的正常交流。而一口流利的，專業(yè)詞匯把握準(zhǔn)確的英語(yǔ)，則會(huì)給對(duì)方留下深刻的印象，從而加深交流，真正達(dá)到交流的目的?？上攵?，兩者的差距。If we are not very good control over his research in the field of English expression, you will meet you when you communicate with foreign experts such as problem, affect our normal communication.And fluent, professional vocabulary to grasp English accurately, will leave deep impression to the other side, thus deepening exchanges, truly achieve the goal of communication.It is conceivable that the gap.最后，專業(yè)英語(yǔ)是高等學(xué)校研究生階段各專業(yè)的一門重要輔助課程，是基礎(chǔ)英語(yǔ)的延伸，其目的是為了拓寬學(xué)生的專業(yè)詞匯量和閱讀量，特別是強(qiáng)化英文表達(dá)方法，為將來的學(xué)術(shù)論文的閱讀、寫作和交流打下堅(jiān)實(shí)的基礎(chǔ)。Finally, specialized English is a high school graduate student stage is an important supplementary course of each professional is the extension of basic English, its purpose is to broaden the students' professional vocabulary and reading, especially to strengthen the English expression method, for the future of academic papers lay a solid foundation for reading, writing and communication.電力專業(yè)是個(gè)高新技術(shù)的學(xué)科，為了追蹤該學(xué)科的動(dòng)態(tài)并趕上國(guó)際水平，必須熟練的掌握該專業(yè)的英語(yǔ)詞匯量及表達(dá)方式；Electricity is a high-tech professional disciplines, in order to track the dynamics of the discipline and catch up with the international level, must be skilled to master the professional English vocabulary and expressions;電力專業(yè)學(xué)生畢業(yè)后在很大程度上面臨的是教學(xué)和科研，必須了解國(guó)內(nèi)外地理理領(lǐng)域的最新動(dòng)態(tài)，并需要經(jīng)常查閱文獻(xiàn)、寫科研論文、參加學(xué)術(shù)會(huì)議等；The power professional students after graduation to a great extent, is facing the teaching and scientific research, must grasp the newest trend of domestic foreign LiLi field, and need to consult the literature often, write research papers, attending conferences, etc.;此外，畢業(yè)生就業(yè)實(shí)行雙向選擇，自主擇業(yè)，人才市場(chǎng)對(duì)于復(fù)合型人才的需要越來越多。因此，電力專業(yè)英語(yǔ)課程的開設(shè)就顯得尤為重要。In addition, graduate employment to realize two-way choice, choose their career, talent market need more and more interdisciplinary talents.English is particularly important, therefore, geographic location.對(duì)于專業(yè)英語(yǔ)這門課的建議有如下幾點(diǎn)：For professional English this course suggestion as follows: 首先、希望可以把速度放慢些，不一定要講那么多，但是講過的句子都能講清楚，重質(zhì)不重量，因?yàn)橛⒄Z(yǔ)句子就那幾大種，當(dāng)方法完全掌握便可舉一反三。First of all, the hope can slow down the speed, don't have to speak so much, but can clearly spoken sentences, quality over quantity, because the English sentence that several big kinds, when master can extrapolate method completely.第二是，希望對(duì)于句子中的一些重要詞匯、短語(yǔ)、句型要更加重視，特別是那些重要的，應(yīng)該著重講述，以實(shí)現(xiàn)記憶和應(yīng)用。The second is that hope for some important words, phrases, sentence patterns in the sentence to pay more attention to, especially those that are important, should focus on, in order to realize the memory and the application.第三是，老師應(yīng)該除了分析句子成分之外，還應(yīng)該分析這個(gè)句子應(yīng)該怎么翻譯，有什么翻譯技巧，通過怎樣的翻譯才能把句子翻譯地流暢，翻譯得好。The third is that the teacher should be in addition to the analysis of sentence composition, also should be analyzed should be how to translate this sentence, what translation skills, through the translation to translate the sentence with how smooth, is a good translation.最后，我真的覺得用這本書作為學(xué)習(xí)教材，不是那么地好，句子不適合四六級(jí)的誰(shuí)平也不怎么針對(duì)考研。希望如果老師有時(shí)間，再換一個(gè)上課教材。而且發(fā)現(xiàn)我們老師對(duì)句子語(yǔ)法掌握的也不是那么系統(tǒng)，有很多是知道卻很難說明白，建議老師看看何凱文的長(zhǎng)難句。Finally, I really think that this book was used as learning materials, is not so good, the sentence is not suitable for the band 4 and band 6 who also don't for one's deceased father grind.Hope that if the teacher had the time, in another class teaching materials.And find that our teacher of a sentence grammar is not so system, there are a lot of know but it's hard to understand, suggested that the teacher see He Kaiwen long difficult sentences.

第四篇：中英文對(duì)照文章⑥

If如果

If you can keep your head when all about you Are losing theirs and blaming it on you;

If you can trust yourself when all men doubt you, But make allowance for their doubting too;

If you can wait and not be tired by waiting,Or, being lied about,don't deal in lies,Or, being hated, don't give way to hating,And yet don't look too good, nor talk too wise;

If you can dreamand not make thoughts your aim;If you can meet with triumph and disaster

And treat those two impostors just the same;If you can bear to hear the truth you've spoken Twiseted by knaves to make a trap for fools,Or watch the things you gave your life to broken, And stoop and build 'em up with wornout tools;

If you can make one heap of all your winnings And risk it on one turn of pitch-and-toss,And lose, and start again at your beginnings And never breathe a word about your loss;

If you can force your heart and nerve and sinew To serve your turn long after they are gone, And so hold on when there is nothin in you

Except the Will which says to them:“Hold on!”;

If you can talk with crowds and keep your virtue, Or walk with Kings-nor lose the common touch;If neither foes nor loving friends can hurt you;If all men count with you, but none too much;If you can fill the unforgiving minute

With sixty second' worth of distance run-

Yours is the Earth and everything that's in it, Andyou'll be a Man my son!

如果所有人都失去理智，咒罵你，你仍能保持頭腦情形；

如果所有人都懷疑你，你仍能堅(jiān)信自己，讓所有的懷疑動(dòng)搖；

如果你要等待，不要因此厭煩，為人所騙，不要因此騙人，為人所恨，不要因此抱恨，不要太樂觀，不要自以為是；

如果你是個(gè)追夢(mèng)人——不要被夢(mèng)主宰；

如果你是個(gè)愛思考的人——光想會(huì)達(dá)不到目標(biāo)； 如果你遇到驕傲和挫折

把兩者當(dāng)騙子看待；

如果你能忍受，你曾講過的事實(shí)

被惡棍扭曲，用于蒙騙傻子；

看著你用畢生去看護(hù)的東西被破壞，然后俯身，用破爛的工具把它修補(bǔ)；

如果在你贏得無數(shù)桂冠之后?

突遇顛峰下跌之險(xiǎn)，失敗過后，東山再起，不要抱怨你的失??；

如果你能迫使自己，在別人走后，長(zhǎng)久堅(jiān)守陣地，在你心中已空蕩蕩無一物?

只有意志告訴你“堅(jiān)持！”；

如果你與人交談，能保持風(fēng)度，伴王行走，能保持距離；

如果仇敵和好友都不害你；

如果所有人都指望你，卻無人全心全意； 如果你花六十秒進(jìn)行短程跑，填滿那不可饒恕的一分鐘—— 你就可以擁有一個(gè)世界，這個(gè)世界的一切都是你的，更重要的是，孩子，你是個(gè)頂天立地的人。

第五篇：機(jī)械名稱中英文對(duì)照

一、除大塊機(jī)Eliminates the bulk machine

二、齒型篩分除雜物機(jī)The screening and eliminates the sundry goods machine

三、振動(dòng)煤箅Vibration Coal Grate

四、滾軸篩Roller Screen

五、滾筒篩Trommel Screen

六、振動(dòng)概率篩Vibration Probability Screen

七、減振平臺(tái)Antivibration Platform

八、布料器Distributing Device

九、皮帶機(jī)頭部伸縮裝置Conveyer Belt Telescopiform Device

十、膠帶給料機(jī)Belt Feeder

十一、往復(fù)式給料機(jī)Reciprocating Feeder

十二、振動(dòng)給煤機(jī)Vibrator Feeder

十三、葉輪給煤機(jī)Coal Impeller Feeder

十四、埋刮板輸送機(jī)Buried Scraper Conveyer

十五、螺旋輸送機(jī)Screw Conveyer

十六、板式喂料機(jī)Apron Feeder

十七、緩沖彈簧板式大塊輸送機(jī)Buffer Spring Apron Bulk Converyor

十八、斗式提升機(jī)Chain-Bucket Elevator

十九、TD75、DTⅡ型帶式輸送機(jī)Type TD75/DTII Belt Conveyer

二十、電動(dòng)三通3-Through-Chute With Electric Drive Gate 二

十一、重力式煤溝擋板Gravity Type Coal Ditch Baffle

二十二、物料穩(wěn)流器Material Constant Staticizer

二十三、犁式卸料器、刮水器Plough Type Tripper/Wiper 二

十四、棧橋沖洗器Flusher

二十五、噴霧除塵系統(tǒng)Exhaust System 二

十六、緩沖鎖氣器Buffer Air Lock 二

十七、緩沖滾筒Snub Pulley二十八、二十九、三

十、緩沖平臺(tái)Buffer Platform 膠帶防撕裂保護(hù)裝置Belt Protective Device 鏈斗卸車機(jī)Bucket-Chain Unloader