机械工程英语课后习题答案（精编版）

1、第一课第 9 页1. 机械工业用于制造产品的材料，可以分为金属材料、 聚合物、 陶瓷和复合材料。the materials used for manufacturing products can be divided into four categories: metallics, polymerics, ceramics and composites. 2. 金属可以分为有色金属和黑色金属。metallics can be classified into non-ferrous and ferrous metallics. 3.塑料可以分为热固性塑料和热塑性塑料。plastics cab b

2、e grouped into thermosets(thermosetting plastics) and thermoplastics.4. 复合材料可以由两种或两种以上性质不同的材料组合，保留各自的特点，得到单一材料无法比拟的、优越的综合性能。a composite consists of two more kinds of different materials, with e ach material keeping its own property, to get the superior synthetical (combined) performance which is unp

3、aralled (unmatched) by that of the individual material.5. 当其所处的工作环境变化时， 智能材料能改变其性能、 颜色和形状等。an intelligent material can change its property, color, shape and so on when its working environment changes.第二课第 17 页 2. 汉翻英1. 材料的特性可分为物理特性和化学特性两大类。the properties of a material can be divided into two main gr

4、oups: p hysical and chemical property.2. 塑性材料在拉伸载荷的作用下应力到达屈服强度时，产生塑性变形。when the stress of a material under the action of tensile load reache s yield strength, it will produce plastic deformation.3. 除软钢等材料有明显的屈服点外， 合金钢和有色合金等塑性材料无明显的屈服点。except that materials such as mild steel have obvious yielding po

5、int, plastic materials such as alloy steel and non-ferrous alloys have no o bvious yielding point.4. 脆性材料拉伸时， 以抗拉强度为极限应力， 压缩时以抗压强度为极限应力。when a brittle material is stretched, the tensile strength is used as its ultimate stress, and when the material is compressed, compressive str ength is used as its

6、 ultimate stress.5. 蠕变是指材料在恒定温度和恒定应力的长期作用下，随着时间的延长会缓慢的发生塑性变形的现象。creep is referred to the phenomena that under the long-time action of constant temperature and load, the material will slowly produce pl astic deformation with the extension of time.第五课第 39 页 2. 汉翻英1. 将金属从矿石中别离出来的过程叫冶炼。the process in wh

7、ich metal is separated from ore is called smelting.2. 几乎所有的黑色金属中都含有碳。almost all the ferrous metallics contain carbon. 3.影响铸件质量的因素很多。the factors that affect the quality of a casting are numerous. 4.通 常认为金属铸造是艺术与科学的结合。it is usually believed that metal casting is a combination of art and sci ence. 5.熔模

8、铸造具有很多独特的优点。investment casting has many peculiar advantages.第六课第 45 页 2. 汉翻英1. 今天，在锻造工艺中，金属的成形并非总是采用加热和锻打的方法。today，in forging process, metal forming does not always use the method of heating and hammering.2. 液压机锻锤被广泛地用于锻造工艺中。hydraulic presses and the hammer are widely used in forging proce ss.3. 随着锻

9、造技术的进步， 许多以前认为不可能锻的材料现在也可通过常规锻造工艺进行加工。with the development of forging technology, many materials which was believed that it was impossible to be forged can now be forged wi th the regular forging process.4. 锻造就是要使金属材料变形为所需要的形状，而不同的材料对外界所施加的变形力的反应极不相同。the purpose of forging is to make the shape of me

10、tal to be changed into what is needed, and the responses of different materials to the de forming force exerted by outsides are extremely different.5. 锻造设备的行为是锻造技术发展的一个重要课题，因为它直接影响着锻造工艺的效果。the behavior of forging equipments is an important topic in the devel opment of forging technology, because it

11、directly influences the effect s of forging process.第九课 2汉翻英1螺杆用来传递运动和力。screw threads are used to transmit motion and force. 2. 铆接既可以是搭接也可以是对接。rivet joints can be either a lap or a butt joint.3. 焊接残余应力是由于热膨胀和收缩不均匀产生的。welding residual stress is produced by the uneven thermal expansio n or contraction

12、 4. 在焊接设计时，要考虑安全因素。safety factors should be considered in welding design.5. 胶接连接的强度取决于树脂对金属外表的粘附力和树脂本身分子之间的结合力。the strength of adhesive joint is determined by the adhesion of the resin to the metal surfaces, and the cohesion between the molecules of the resin itself.第十课 2汉翻英1带传动和链传动联接两个或多个轴来传递旋转运动和运

13、动。belt and chain are used to connect two or more shafts for transmission of rotation and power. 2.链传动的传动比计算跟齿轮的传动一样，即与齿数成反比。the speed ratio of a chain drive is the same as that of a gear drive, namely, the inverse ratio of the tooth number.3. 链长必须是节距即一个连节的长度的倍数，节距的数目最好是偶数。the chain length must be a

14、multiple of the length of one shackle an d it is preferable that the number of pitches is even.4. 行星轮系在较小的空间内能得到较大的传动比。planetary gear trains can get larger speed ratio in a small package.5. 凸轮机构能把旋转运动转换成直线运动或摆动。cam mechanism can convert rotary motion into linear or oscillating (angular) motion.第十三棵1

15、液压系统有动力源、执行原件、控制元件和辅助系统组成。a hydraulic system consists of power source, actuators, control device s and auxiliary system. 2 根据动力源的不同，液压系统可分为恒流系统和恒压系统。depending on the power resource, a hydraulic system can be divided into a constant flow system and a constant pressure system.3) 齿轮泵是容积泵种结构最简单但效率最高的一种泵

16、。a gear pump is the simplest in configuration and the most efficient p ump of positive displacement pump.4) 液压系统中另一种重要元件是阀，主要有三种类型的阀：溢流阀、流量控制阀和方向控制阀。another important device in hydraulic system is valve. there are ma inly three types of valve: relief valve, flow control valve and direction control v

17、alve.lesson 14 page 1002. translate the following sentences into english:1) 在车床加工中，工件的旋转为主运动，刀具的运动为进给运动。in turning machining, the turning of the work-piece is primary motio n and the motion of the tool is feed motion.2) 常用的铣床有以下几种：1立式铣床； 2卧式铣床； 3龙门铣床。the commonly used milling machines are as the fol

18、lowing kinds:1)horizontal milling machine;2)vertical milling machines;3) plano-millers。3磨床加工形成的切屑非常小，以至难于与粉尘相区别。chips formed by a grinding machine are so small that it is difficult to tell the difference between them and dusts.4)机械加工在工业生产中得到了非常广泛的应用，它可以改变零件的几何形状，从而得到所需要的尺寸和外表质量。machining are widely

19、used in industry production。it can change the geometric configuration of a work-piece and form t he desired size and surface quality 。age 119第 17 课1电化学加工是一种电解过程，依靠电解池作为阴极和工件作为阳极发生电化学分解去除金属。ecm(electrochemical machining) is a electrolytic process, in which m etals are removed by means of electrochemi

20、cal decomposition using e lectrolytic reservoir as the cathode and a work-piece as the anode.2) 类似电化学加工过程的第一个专利是在1929年由gusseff 申请的 。 the first patent on a process resembling ecm was filed by guss eff in 1929.3) 工件和加工工具分别被制成电解电池的阳极和阴极，它们的电势差大约是 10 伏。a work-piece and a tool are respectively made into

21、an anode and a cathode of an electrolytic cell and the potential difference between the t wo electrodes is about 10 v.4) 由于其速度和操作简单，电化学去毛刺常用一种固定的、稳定的阴极工具进行加工 。 owing to its speed and simplicity of operation, electrochemical deburring can often be performed with a fixed, stationary cathode tool.第 18 课 page 1251早在 1768 年前，人们就发现了电火花放电能引起金属的腐蚀。as early as the time before 1768, it was found th