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1、1宿迁应用职业技术学院（校）20072008 学年度第一学期机电专业英语 期末考试试卷（试卷编号 A ）（闭 卷 100 分钟）题号 一 二 三 四 五 六 总分 复核人实得分阅卷人一.Translations of Phrases and Expressions(215=30)1.heat treatment2.room temperature 3.raw material4.worm gear5.flame cutter6.canned routine7.as far as be concerned8.at the points where9.be divided by10.at righ
2、t angles to11.induced current12.controlled varriable13.closed system14.action-one15.carbon dioxide系 专业 年级 班 学号 姓名 装 订 线.2二Calculations(5+10=15)1.How much current will flow through a 24 electric heater when voltage of 240V is applied?2.A transformer supplies a load with 30A at 120V .If the primary vo
3、ltage is 2400V,find:(a)the secondary voltamperes;(b)the primary voltamperes;And (c)the primary current.三Reading Comprehensions(30)Iron and SteelThe earth contains a large number of metals which are useful to man.One of the most important of these is iron.Modern industry needs considerable quantities
4、 of this 3metal,either in the form of iron or in the form of steel.A certain number of non-ferrous metals,including aluminum and zinc,are also important,but even today the majority of our engineering products are of iron or steel.Moreover,iron possesses magnetic properties,which have made the develo
5、pment of electrical power possible.The iron ore which we find in the earth is not pure.It contains some impurities which we must remove by smelting.The process of smelting consists of heating the ore in a blast furnace with coke and limestone,and reducing it to metal.Blasts of hot air enter the furn
6、ace from the bottom and provide the oxygen which is necessary for the reduction of the ore.The ore becomes molten,and its oxides combine with carbon from the coke.The non-metallic constituents of the ore combine with the limestone to form a liquid slag.This floats on top of the molten iron,and passe
7、ss out of the furnace through a tap.The metal which remains is pigiron.We can melt this down again in another furnacea cupolawith more coke and limestone,and tap it out into a ladle or directly into mould.This is cast-iron.Cast-iron does not have the strength of steel.It is brittle and may fracture
8、under tension.But it possesses certain properties which make it 4very useful in the manufacture of machinery.In the molten state it is very fluid,and therefore it is easy to cast it into complicated shapes.Also it is easy to machine it.Castiron contains small proportions of other substances.These no
9、n-metallic constituents of cast-iron include carbon,silicon and sulphur,and the presence of these substances affects the behaviour of the metal.Iron which contains a small quantity of carbon,for example wrought-iron,behaves differently from iron which contains a lot of carbon.The carbon in cast-iron
10、 is present partly as free graphite and partly as a chemical combination of iron and carbon which we call cemmentite.This is a very hard substance,and it makes the iron hard too.However ,iron can only hold about 1.5% of cementite.Any carbon content above that percentage is present in the form of fre
11、e graphite.Steel contains no free graphite,and its carbon content ranges from almost nothing to 1.5%.We make wire and tubing from mild steel with a very low carbon content,and drills and cutting tools from high carbon steel. Questions1. (33=9)True and false statements(1) ( )Heat treatment is a proce
12、ss of heating metals to 5alter their mechanical properties.(2) ( )A steel part must be heated to the critical temperature in order to be completely austenitized.(3) ( )Annealing is not a method of softening.2. (33=9)Rephrasing(1)(After it is machined to shape)the punch must be hardened.(2)When a ste
13、el part is heated in a hardening furnace,a temperature(50 to 100 degree higher than the critical temperature)is usually selected.(3)(After)the heating (process)is completed,the steel part may be quenched into cold water.3. (211=22)Complete the following abstract of the text.Heat treatment refers to
14、the process of heating and cooling a metal to its mechanical properties.After being heat treatd a metal part must be ground to and provide.In order to be either hardened or softened,the steel must be,that is,its temperature must be taken the 6critical temperature line.Also,it must be held at tempera
15、ture for sufficient time.The residence time in the furnace depends on the operatorswith any particular steel.The determines whether the steel will be hardened or softened.A steel part will be hardened when quenched into ,and softened whrn cooled in .There are several softening methods.Annealing leaves the steel in the condition.四Translations of these Sentences(55=25)1.A tool steel intended to be machined into a punch may first be softened so that it can be machined.2. The rate of metal removal can be increased b
