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1、 最新消息1-2the benefits of civilization which we enjoy today are essentially due to the improved quality of products available to us .文明的好处我们享受今天本质上是由于改进质量的产品提供给我们。the improvement in the quality of goods can be achieved with proper design that takes into consideration the functional requirement as well
2、 as its manufacturing aspects. 提高商品的质量可以达到与适当的设计,考虑了功能要求以及其制造方面。The design process that would take proper care of the manufacturing process as well would be the ideal one. This would ensure a better product being made available at an economical cost.设计过程中,将采取适当的照顾的生产过程将是理想的一个。这将确保更好的产品被使可得到一个经济成本。Ma
3、nufacturing is involved in turning raw materials to finished products to be used for some purpose. 制造业是参与将原材料到成品用于某些目的。In the present age there have been increasing demands on the product performance by way of desirable exotic properties such as resistance to high temperatures, higher speeds and ext
4、ra loads.在现在的时代已经有越来越多的产品性能要求的理想的异国情调的性能如耐高温,更高的速度和额外的负载These in turn would require a variety of new materials and its associated processing.这些反过来需要各种新材料及其相关的处理Also, exacting working conditions that are desired in the modern industrial operations make large demands on the manufacturing industry.这些反过
5、来需要各种新材料及其相关的处理。同时,严格的工作环境,需要在现代工业操作使大型制造业的需求.Further, the economics of the manufacturing operation is a very important consideration. 此外,经济学的生产操作是一个非常重要的考虑因素。To be viable in the modern environment, a product has to be petitively priced besides having the functional and aesthetic appeal.是可行的在现代环境中,一
6、个产品必须具有价格竞争力除了具有功能性和审美情趣。 Therefore, it is necessary for the engineer to give a proper thought to various aspects of manufacturing.因此,它是必要的让工程师给适当的认为制造业的各个方面。 Manufacturing processes is a very fundamental subject since it is of interest not only to mechanical engineers but also to those from practic
7、ally every discipline of engineering. 制造过程是一个非常基本的主题,因为它是有趣的,不仅机械工程师但同样从几乎每个学科的工程。It is so because engineering as a whole is meant for providing various materials for human consumption.它是如此因为工程作为一个整体是用来提供各种材料供人类食用For various products such as plant machinery required for chemical, civil, electrical,
8、electronic, textile, etc., the manufacturing process forms a vital ingredient.对于不同的产品,如植物机械所需的化工、土木、电气、电子、纺织等,生产过程形成一个至关重要的因素.A detailed understanding of the manufacturing processes is thus essential for every engineer. 详细了解生产流程是必不可少的每个工程师这样。This helps him appreciate the capabilities, advantages and
9、 also the limitations of the various manufacturing processes.这有助于他欣赏能力、优势和局限性,各生产工序。 This in turn helps in the proper design of any product required for him.这反过来有助于正确的设计的任何产品需要他。 Firstly, he would be able to assess the feasibility of manufacturing from his designs.首先,他将能够评估制造的可行性从他的设计。 He may also f
10、ind out that there more than one process available for manufacturing a particular product and so he can make a proper choice of the process which would require the lowest manufacturing cost and would deliver the product of desired quality. 他可能也发现有超过一种过程用于生产特定的产品,所以他可以使一个适当的选择过程,需要最低的制造成本和交付产品的期望质量。H
11、e may also modify his design slightly to suit the particular manufacturing process he chooses.也可以修改自己的设计稍微适应特定的制造过程他选择. Manufacturing is defined by the Merriam Webster online dictionary as to make into a product suitable to use. 制造业是梅里厄姆-韦伯斯特词典定义的在线词典使成一个产品适合使用。Manufacturing remained as a craft till
12、 the first industrial revolution towards the end of the 18th century with low volumes and single-piece productions.制造业仍然作为一个工艺直到第一次工业革命对18世纪末的低量和单件生产。 It required highly skilled craftsmen to individually produce the pieces and fit them when the assembly was required. 它需要高度熟练的工匠来单独生产件和适合他们的需要时组装。This
13、 was a slow and expensive process , but in the absence of any machines, that was the only thing that was possible.这是一个缓慢而昂贵的过程,但在缺乏任何机器,这是唯一可能的。 The availability of the steam engine and coal-fire furnaces made the invention of a number of steam-power driven machinery to greatly increase the manufact
14、uring capacity. 蒸汽引擎的可用性和煤火熔炉使发明一种数量的全局驱动机械制造能力大大增加。A large number of inventions related to machine tools took place during this period and continued into the 19th century. 大量的发明与机床发生在这一时期,持续到19世纪。对十九世纪末的发明电力和更好的工程材料、生产操作变得更有效率。Towards the end of the 19th century with the invention of electricity an
15、d better engineering materials, manufacturing operations became more productive. The developments in the automobiles at the beginning of the 20th century are instrumental in the growth of a variety of manufacturing methods and practices.对十九世纪末的发明电力和更好的工程材料、生产操作变得更有效率。汽车的发展在20世纪初期是工具性成长的各种生产方法和实践。The
16、re are a large number of processes available to the engineer for manufacture.有大量的流程提供给工程师制造。 These processes can be broadly classified into four categories.这些过程可以大致分为四类Casting processes forming processes fabrication processes material removal processes铸造工艺成形过程工艺制备材料去除的过程These are the only processes
17、where liquid metal is used. 这些是唯一使用过程中,液态金属。Casting is also one of the oldest known manufacturing processes.铸造是一个已知的最古老的制造过程。它需要准备一个腔通常在耐火材料类似于最终对象是。 It required preparation of a cavity usually in a refractory material to resemble closely the final object to be made.它需要准备一个腔通常在耐火材料类似于最终对象是。 Molten m
18、etal is poured into this refractory mould cavity and is allowed to solidify. 金属熔液注入这耐火模腔和允许巩固。凝固后的对象被删除从模具。The object after solidification is removed from the mould.凝固后的对象被删除从模具。 Casting processes are universally used for manufacture of a wide variety of products. 铸造过程是普遍用于制造各种各样的产品The principal pro
19、cess among these is sand casting where sand is used as the refractory material. 其中的主要过程是砂铸,砂用作耐火材料。The process is equally suitable for the production of a very small batch as well as on a very large scale.这个过程同样适用于生产的一个非常小的批量以及一个非常大尺度。 Some of the other casting processes for specialized needs are一些其
20、他的铸造工艺专业需求Shell-mould casting. 壳型铸造permanent-mould casting硬模铸造Precision-investment. 精密的投资casting die-casting铸造压铸Plaster-mould casting. 石膏型铸造Centrifugal casting离心铸造 These are solid state manufacturing processes involving minimum amount of material wastage and faster production.这些都是固态制造过程涉及最少的材料损耗和更快的
21、生产。 In a forming process, the metal may be heated to a temperature, which is slightly below the solidus temperature and then a large force is applied such that the material flows and takes the desired shape. 在成形过程中,金属可能被加热到一个温度,略低于固相线温度,然后一个大力量是应用的材料流和需要所需的形状。The desired shape is controlled by means
22、 of a set of tools called dies, which may be pletely closed or partially closed during manufacture. 所需的形状是通过控制的一组工具称为死亡,这可能是完全封闭或部分封闭在制造。These processes are normally used for large-scale production rates. These are generally economical and in many cases improve the mechanical properties too. 这些过程通常用
23、于大规模的生产速度。这些通常是经济和在许多情况下改善机械性能太Some of the metal forming processes are rolling ,extrusion ,drop forging ,wire drawing ,press forging ,sheet metal operations ,upset forging . 一些金属成形过程是轧制、挤压、落锤锻造,拉丝,按锻造、金属板操作、顶锻 These are secondary manufacturing processes where the starting raw materials are processed
24、 by any of the previous manufacturing processes described .这些是二次制造过程的起始原料处理前面的任何制造过程描述。It essentially, envolves joining pieces either permanently or temporarily so that they would perform the necessary function. 它从本质上讲,envolves加入碎片要么永久或暂时如此,他们将执行必要的功能。The joining can be achieved by either or both of
25、 heat and pressure and/or a joining material.的加入可以达到的一种或两种热量和压力和/或加入材料。 Many of the steel structural constructions we see are first rolled and then joined together by a fabrication process.许多钢结构建筑,我们看到的是第一卷,然后连接在一起的工艺过程。Some of the processes of interest in this category are gas welding, cold welding
26、, electric arc welding, brazing, electric resistance welding, soldering, thermit welding.一些感兴趣的过程都属于这一类气体焊接、冷焊接、电弧焊、钎焊、电阻焊、钎焊、铝热焊。These are also secondary manufacturing processes where the additional unwanted material is removed in the form of chips from the blank material by a harder tool so as to
27、obtain the final desired shape.这些是二次制造工艺,额外的不必要的材料去除的形式的芯片从空白材料的困难,得到了工具最终想要的形状。 Material removal is normally the most expensive manufacturing process because more energy is consumed and also, a lot of waste material is generated in the process. 材料去除的通常是最昂贵的制造过程,因为更多的能量消耗,同时,大量的废弃物产生的过程。Still this i
28、s widely used because it delivers very good dimensional accuracy and good surface finish. 这仍是广泛使用的,因为它提供了非常良好的尺寸精度和良好的表面光洁度。It also generates accurate contours. Material removal processes are also called machining processes.它还生成精确的轮廓。材料去除过程也称为加工过程。The various processes in this category are turning,
29、grinding, drilling, broaching, shaping and planning, sowing, milling.各种流程在这个类别是车削、磨削、钻孔、扩孔、塑造和规划、播种、铣削。All these manufacturing processes have been continuously developed so as obtain better products at a reduced cost. 所有这些制造工艺不断发展,获得更好的产品在降低成本。Of particular interest is the development of puter and t
30、heir effect on the manufacturing processes.特别感兴趣的是计算机的发展及其影响制造过程。 The advent of puters has remarkable difference to most of the above manufacturing processes. 电脑的出现有显著差异,最上面的制造过程。They have contributed greatly to both automation and designing the process.他们作出了巨大贡献两个自动化和设计过程An important responsibility
31、 of the engineer is to choose a manufacturing process, which makes the required quality of a product to the specifications and at the lowest cost possible.工程师的一个重要职责是选择一个以尽可能低的成本制造出所需质量的产品的制造过程。 To fulfil both the conditions, one would have to do a break-even analysis of the various processes suitab
32、le for the production of the given object.为了实现这两方面的目标,工程师必须针对给定的目标对不同的制造过程做出适当的盈亏平衡分析,In the break-even analysis, two types of costs are considered:在盈亏平衡分析中要考虑两方面的成本,Fixed cost relates to the initial investment on the equipment and tools required for the process. This cost would be constant and does
33、 not vary with quantity produced.固定成本与制造过程相关联的所有设备和工具的投资是固定成本,固定成本是固定的,不以产量而异,另一方面是可变成本,因实际产量不同而有差别。Variable cost on the other hand, varies with the actual number of objects made. This takes into account the raw material required, energy consumed, labour cost, cost of special toolings, cost of tools
34、 used and other administrative overheads. requirement of these are directly proportional to the quantity produced.可变成本计算进的所需原材料消耗、能量消耗劳动力成本、特殊工具成本和其他的行政管理费用,这些通常和产量是成比例的The same is shown in graphical form in Fig. 1.1.Normally, as the quantity of produced decreases. This is due to the fact that the f
35、ixed cost associated with the production remains constant.相同的显示在图形化的形式在图1.1。通常,作为生产的数量减少。这是由于这样的事实,即固定成本与生产有关保持不变。If the engineer has to make a choice between two different processes for manufacturing the same ponent, he may first estimate the fixed costs and variable costs for both the processes an
36、d then plot the total cost curves for both as in Fig. 如果一位工程师必须制造同一产品的两种不同工艺做出选择,他必须首先估计两种工艺的总的固定成本和可变成本,然后绘制总成本曲线,The point where both these curves intersect is called the break-even point. 这些曲线的交点叫做盈亏平衡点,It implies that the first process will be economical if the quantity of production is less tha
37、n that of the break-even point, that while beyond it the second process is economical.这意味着如果产量比盈亏平衡点低第一种工艺是经济的,如果产量超过该点那么,第二种是经济的。The break-even quantity, n, can also be obtained by equating the total costs in both the processes.保本量,n,也可以把获得的总成本的过程。 This would give a positive value when a fixed and
38、variable costs are lower than the other process, then the latter process is always uneconomical whatever may be the production quantity.这将给一个积极的价值当一个固定和可变成本是低于其他过程,那么后者过程总是不经济的任何可能的生产数量。The manufacturing of a ponent may involve more than one process or more variants of the same process. 制造一个组件可能会涉及到
39、多个进程或更多的变种相同的过程。In the first case, it is necessary to consider the costs of all the processes while puting the total cost for each of the processes在第一种情况下,有必要考虑成本的所有工序,同时计算总成本的每个过程The deformation caused in a material is of two types, elastic and plastic.在材料中引起的变形可以分为两种类型,弹性变形和塑性变形Elastic deformation
40、 is that part of the deformed material which when the applied load is removed, would spring back to its normal shape. 弹性变形是指材料上所施加的载荷被移除后能恢复原来形状的变形。Plastic deformation is on the other hand , permanently set in a material and cannot be regained.,塑性变形是另一方面,永久的不可回复的变形。 Tensile strength is measured by a
41、 tensile test carried out on a universal testing machine. 拉应力通过在一种通用的测试机上实施的测试实验测得。This involves the preparation of a test specimen as per standard shown in Fig.2.1包括图2.1所示作为标准的样本的准备。 The standard specimen can be either rectangular or cylindrical. 样本可以是矩形的也可以是圆柱形的,Rectangular is generally used for p
42、late-type specimens.矩形的通常被用于板式样本, Care has to be taken to see that the specimen is prepared in a way such that the surface is smooth and without any deep cracks or nicks.必须保证样本的表面是平滑的、没有任何裂缝或刻痕。 The tensile testing machine consists of a heavy test frame with a lower fixed beam, and an upper crosshea
43、d which is the moving beam used to apply the tensile force on the specimen as shown in Fig2.2.拉伸试验机由一个带有一个较低的横梁和一个在样本上施加拉力的联杆器的巨大测试机架组成。The specimen is mounted between two grips ,one attached to the fixed beam and the other attached to the crosshead. 样本只能装在两个抓爪间,一个附加在横梁上,另一个附加在连杆器上,An extensometer i
44、s attached to the specimen to measure the elongation of the test specimen as the force is being applied .当施加负载时一个伸长仪被加到样品上来测量测试样本的伸长量。Then a uniformly increasing tensile load is applied on the specimen. 然后一个均匀增加的载荷被施加到样本上,The movement of the crosshead relative to the fixed beam generates strain with
45、in the specimen and a corresponding load.连杆器和横梁的相对运动在样本上形成力和一个相应的载荷。 As the load increases, the specimen initially gets elastically elongated. As can be noted from Fig2.1, the central portion is smaller pared to the gripping section.随着载荷的增加,样本首先产生弹性变形,如图2.1所示,相比之下中心部分比引人瞩目的区域要小。 On further elongatio
46、n, the specimen starts necking at some point (within the gauge marks) when the material goes beyond the elastic range. 继续加载荷,当材料超过弹性围样本在一些点处会变窄。The reduced width of he specimen would be reduced under the force of the load and finally develop fractures when the test is pleted. 在载荷的作用下样本减少的宽度会减少,当测试结束
47、时样本会最终断裂。If the necking does not happen within the gauge marks, the test need to be repeated with a different specimen. 如果断裂没有在标准刻度发生,测试需要用不同的样本重新做。During the test , a record is maintained of the load and the corresponding elongation. 在测试中应持续记载载荷和相应的伸长量。The stresses and strains are calculated from t
48、he above data and plotted in a diagram as shown in Fig.2.3.应力和力可以由上述数据计算并被绘制成图2.3所示图标。It can be observed that there is a limit up to which the applied stress is directly proportional to the induced strain. 可以观察到所施加的力和诱发的力直接成比例,This is represented by the linear portion of the curve up to A which is t
49、ermed as the proportional limit. 这一点可以有延伸到A点的线性曲线表示,A点叫做比例极限。The end of this linear portion is the yield point of the material above which the material starts plastically by the bow-shaped portion of the cube. 线性部分的终点叫做屈服点,在屈服点以上材料开始弹性变形,拱形曲线表明在弹性围,应力与力之间没有明显的线性关系。Finally, the specimen breaks when t
50、he force of the applied load goes beyond the limit that can be borne by the material.最终样本在所施加载荷超过材料所能承受的极限时发生断裂。 The proportional limit is often difficult to calculate, therefore, two practical measurements, offset yield strength (OYS) and yield by extension under load (EUL), were developed to appro
51、ximate the proportional limit. 比例极限通常难以计算,因此,两种特殊的测量方法,补偿屈服应力和延伸屈服被发展用于近似代替比例极限。Point B represents the offset yield strength and is found by constructing a line X- B parallel to the curve in the elastic region. 点b通过在弹性围构造一条平行线x-b表示补偿屈服应力。Line X-B is offset a strain amount O-X that is typically 0.2%
52、of the guage length. X-B线补偿了拉伸长度O-X所表示的的应力的0.2%。Point C represents the yield strength by extension under load and is found by constructing a vertical line Y-C. 点C通过在在载荷下的拉伸量并构成曲线Y-C来表示屈服应力。Line Y-C is offset a strain amount O-Y that is typically 0.5% of the guage length. Y-C线补偿拉伸长度O-Y所表示的应力的0.5%。The
53、 ultimate tensile strength , or peak stress, is represented by the point C.最终的拉伸应力或顶点应力由点D表示。 Total elongation, which includes both elastic and plastic deformation, is the amount of uniaxial strain at fracture and is depicted as strain at the point Z.Per cent elongation at break is determined by rem
54、oving the fractured specimen from the grips;总伸长量,包括弹性变形和塑性变形,是断裂时的单轴应变,由Z点的应变表示。 fitting the broken ends together and measuring the distance between guage marks.断裂点的单一伸长量由移动抓爪间的断裂样本决定。 Per cent elongation at break reports the amount of plastic deformation only. The guage length used for measurement
55、is reported with the result.他和断裂点相配合来测量定位刻度间的距离。Similar tests can also be conducted for measuring the pression and shear strength. Hardness is a very important property since the manufacturing depends on it to a great extent.硬度是非常重要的性能,因为制造在很大程度上依赖与他, Hardness is the resistance offered by a material
56、 indentation. Moh的scale of hardness is based on ten standard minerals as shown in Table 2.1. 硬度是材料对压力的抵抗力莫氏硬度测量基于表2.1所示的十种标准矿物。It can be measured by the indentation made by a harder material. . 通常可以由一种坚硬的材料造成的压痕来测量。The indentation made depends upon the applied load, the sharpness of the indentor and
57、 the time for which the applied load is maintained压痕取决于所施加负载,压痕的清晰度取决于负载应用的时间。There are a number of indentation tests to measure the hardness of a material normally. 同场还有许多硬度测试方法来测量材料的硬度。These usually involve a ball, a cone or a pyramid of a harder material which is indented into the material under
58、test with a specified load. 这些测试方法通常是在指定的负载下把由坚硬的材料制成的团块、圆锥体或球椎体压入材料,The permanent indentation thus made is measured to give an indication of the hardness on the given scale for the tests.偶测量这些所产生的永久压痕来在测试给定的围对材料的硬度做出指示。Some precautions that need to be taken during the use of Brinell test are that t
59、he surface of the material whose hardness is being tested should be smooth and even, and there is enough material underneath the indentation and on all sides to give a proper value for the indentation.一些预防措施,需要在使用布氏硬度试验是材料的表面的硬度测试应光滑、均匀,并有足够的材料在压痕和在各方面给予适当的缩进值。The Brinell hardness of steel is roughly related to the tensile strength of the material utilizing the following empirical relationship for plain carbon steels.这个布氏硬度的钢大致与抗拉
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