铸造和铸造过程外文文献翻译、中英文翻译、材料加工铸造外文翻译

外文原文： Casting and its processes 1.1 Introduction Manufacturing process can be classified into two general groups known as primary and secondary processes. The primary processes, namely, casting, forging, cold heading, cold extruding, brake forming, and so on, are those that convert raw material into shapes. These forming methods include both hot and cold working processes and, in general, will still require further finishing operations in order to obtain an end product. The secondary processes are those that bring the part to the dimensions and surface finish specified. One may also include in the secondary processes such operations as heat treating and surface treatments for corrosion resistance, hardness, and appearance. Secondary processes are planning , turning ,milling, drilling , boring , reaming , broaching , grinding , honing ,lapping , polishing , and special methods of metal removal such as electrochemical machining. Operations like screw cutting, tapping, thread milling, gear cutting, and so on ,are secondary processes that are merely adaptations of one of the aforementioned processes that are merely adaption of one of the aforementioned processes. A complete discussion of these procedures is beyond the scope of this text. Therefore, we will confine ourselves to succinct descriptions of the most prominent techniques. 1.2 Castings Castings are identified by the type of mold or the force required toy fill the mold. Molds are either permanent or expendable. The pattern of sand, shell, and plaster molds, however, can be used repeatedly for making new molds. As the metal cools, it takes the shape of the cavity. The basic casting methods are described below. Sand castings. 1. The green sand process is one in which most, bonded sands packed around a wood or metal pattern. The pattern is then removed and molten metal is poured into the cavity .When the metal solidifies, the mold is broken and the casting is removed . Almost any metal can be used, with virtually no limit as to the size or shape of the part . The method permits casting complex components at a low tooling cost and is the most direct route from pattern to casting . Some machining is always necessary with the green sand process, and large castings have rough surface finish .Close tolerances are difficult to achieve, and long, thin projections should not be cast. It is possible , however , to design for bosses, undercuts and inserts .The minimum core hole diameter advisable are aluminum,3| 161|4 in. ；and the minimum section thicknesses advisable are aluminum ,3|16 in .；cooper , 3|32 in .； iron ,3|32 in .； magnesium,5|332 in ；and steel , 1|41|2 in . 2. The dry sand process is similar to the green sand process except that core boxes are used in place of patterns .This method is usually limited to smaller parts than method 1. The sand is bonded with a setting binder, and the core is then oven baked at 300400 to remove the moisture. 3.The carben dioxide sand process is one in which the sand molds are bonded whit sodium silicate solutions and set by forcing carbon dioxide gas through the sand .This type of mold is strong and permits the production of better dimensionally controlled castings than either method 1 or 2 . 4 .The coresand mold process is one where the molds are put together completely from oven baked cores set with organic binders such as oil or dextrines. Shell Mold Casting . This is a process where the molds are made by coating the sand with a thermosetting plastic .The mold is then supported on the outsaid by sand or shot, and molten metal is poured .When the metal has solidified , the mold is broken away from the finished casting. Shell molding produces casting with smooth surfaces, uniform grain structure ,high dimensional accuracy , rapid production rate and minimal amount of finishing operations . The minimum section thickniss castable is 1|161|4 in .but section differences where the maximum minimum ratio is greater than 5 to 1 should be avoided. Bosses, undercuts and inserts are easily cast and the minimum cored hole diameter is 1|81|4 in .The method is relatively costly is limited to few metals. Full-Mold Casting . A process in which a green sand or cold-setting resin bonded is packed around a foamed plastic pattern (for example ,polystyrene ).The plastic pattern is vaporized with the pouring of the molten metal into the mold .An improved casting surface can be obtained by putting a refractory type of coating on the pattern surface before sand packing .The pattern can be one piece or several pieces , depending upon the complexity of the part to be cast . The plastic patterns are handled easily . They do not require any draft ,and produce no flash on the casting . For small quantity production this method can be expensive, depending upon the size and complexity of the casting .The minimum recommended section thickness is 0 .1 in .,and the maximum section thickness is unlimited .Bosses, undercuts , and inserts present no problem in this type of casting . The minimum cored hole diameter is 1|4 in. Permanent Mold Castings .These are formed by a mold that can be used repeatedly . Some applications have reported as many as 25 000 castings being made from the same mold .Usually , the mold requires some redressing after about 3000 uses . The molds are machined of metal (for example ,gray iron ) for casting nonferrous metals and cast itons . Machined graphite molds are used to cast steel. This method produces castings that have a good surface finish as well as a good grain structure ,low porosity ,and high dimensional accuracy .The initial mold cost is relatively expensive, but castings weighing as little as several ounces to castings are limited to relatively simple shapes and forms. The maximum recommended section thickness is about 2.0 in .The minimum thickness , however ,dependsuoon the material being cast as follows :3|16 in .for iton ,3|321|8 in .for aluminum, 5|32 in .for magnesium, and 3|32 5|16 in .for copper .The minimum castable holes are 3|161|4 in .in diameter. Die Casting . A process used extensively in the quantity production of intricately shaped zinc, alumimum, lead and magnesium alloys .The method is limited in use with tin and copper alloys. Castings are formed by forcing molten metal under pressures of 1500-25 000 psi into an accurately machined steel die .The steel die ,which is water cooled ,is held together by a hydraulic press until the metal casting(s) solidifies., To ease the ejection of the cast parts, a lubricant is sprayed on the die forming surface and the ejection pins. For small die cast components .,multiple cavity dies are used . The surface finish of the resulting castings is quite smooth and has excellent dimensional accuracy .Although the cost of production is relatively cheap ,the initial die cost is high .Diecasting is limited to nonferrous metals and by the size of the part that can be cast .The maximum wall section thickness is usually restricted to 3|16 in . but certainly to no greater than 0.50 in. Plaster Mold Casting . These are made by pouring a nonferrous alloy (for example , aluminum ,copper ,or zinc alloy ) into a plaster mold ,which is then broken to remove the solidified casting . The castings produced by this process are smooth, have high dimensional accuracy, low porosity, and can be made in many intricate shapes. The method, however, has disadvantages in that is limited to nonferrous metals, small castings and also requires a relatively long time to make the molds. The minimum wall section thickness is 0.040-0.060 in . for a cast area that is less than 2 sq .in . For larger cast areas ,the minimum wall thickness increased accordingly . The show process, developed within the last decade, is a cost promising method .It employs the use of plaster molds .This procedure produces castings with fine detail and excellent dimensional accuracy and surface finish. Ceramic Mold Casting . This process uses a mold made of a ceramic powder ,binder ,and gelling agent. The mold can also be made of a ceramic facing reinforced with a sand backing .The method is restricted to casting intricate parts requiring fine detail ,close tolerances ,and smooth finishes .The minimum wall thickness recommended is 0.025-0.050 in. There is, however, no limit to the maximum wall thickness. Investment Casting. These are made when parts are desired that are intricate in shape ,have excellent surface finish , and require a high degree of dimensional accuracy .In addition ,this method of casting permits the use of a variety of metal alloys and does not have In addition ,this method of casting permits the use of a variety of metal alloys and does not have any metal flashing to be removed from the finishes casting. The technique of investment casting requires careful workmanship and expensive patterns and moths. The minimum castable wall thickness is about 0.025-0.050 in .and the maximum thickness should not exceed 3 in . Centrifugal Casting . This is a method of casting a shape by pouting the molten metal into a rotating fladk containing the mold .The molds are made of sand ,metal ,or graphite (depending on the metal cast ) and are rotated about their axial centers either in a horizontal or vertical position . Relatively large diameter and bulky components are made are pipe ,gun barrels, hollow shafts ,machinery drive rolls, long sleeves , tubing , and so on .Where the diameter to length ratio is rather large ,the rotational axis can be vertically mounted molds ,the method is called semmicentrifugal casting ,and it is used to make parts such as wheels, turbosupercharger diaphragms , disks ,flywheels ,and so on .Figure 1-5-2 shows a schematic section of a semicentrifugal casting of a cored flywheel . Generally, the method of centrifugal casting is expensive and is also limited in the shapes which can be cast .However ,the castings made by this mehod are very sound and have good dimensional accuracy .It should also be noted that this method is the only way to obtain a large cylindrical part. Continuous Casting. This is a method whereby a molten metal is continuously gravity fed from a ladle into an ingot mold of a desired shape which is open at both ends. As the metal falls through the mold , it takes its shape ,and is rapidly cooled by a water spray .It is then cut to specific lengths. The continuous casting process has the advantage of being low in cost and having a high rate of production .In addition, this method permits casting materials that cannot be extruded. However, continuous casting is restricted to shapes of uniform cross section (that is ,in the direction of casting),The minimum wall thickness depends on the shape being cast . The minimum size of casting is 1|2 in .and the maximum size is about 9 in . 译文： 铸造和铸造过程 1.1 简介 制造过程可分为两个一般群体称为初级和中级的进程。主要过程，即铸造，锻造，冷镦，冷挤压，制动形成等等，使那些原料转换成工件形状 .这些成型方法包括冷热工作程序，以及一般还需要进一步加工工作，以获得最终产品。 二级进程是那 些把部分的尺寸和表面光洁度指明。其中可能也包括在二级处理流程，如工件的热处理和表面处理的耐腐蚀，硬度，和表面粗糙度。其次，进程规划，车削，铣，钻，镗，铰孔，拉削，磨削，珩磨，研磨，抛光，和特殊方法去除金属如电化学加工。行动像螺丝切割，攻丝，螺纹铣削，齿轮加工等，是次要的过程，只是一个适应的过程，上述只是之一的上述进程。 一个完整的讨论这些程序的范围以外的文字。因此，我们将仅限于简洁的描述具有代表性的技术。 1.2 件 铸件所确定类型的模具或部队需要台岛填补模具。铸模或者永久或格局砂，贝壳，和 石膏模具，然而，可重复使用作出新的模具。金属冷却，它的形状腔。基本铸造方法介绍如下。 砂铸件。 1 绿色砂过程是一个潮湿，保税装在一个木制或金属的模式。该模式，然后删除和熔融金属注入模腔。当金属巩固，模具破裂和铸造被删除。几乎所有的金属可用于几乎没有限制的大小或形状的一部分。该法允许铸造复杂零件加工费用低，是最直接的路线从模式铸造。 一些加工始终是必要的绿色型砂进程，并有大型铸件毛坯表面光洁度。关闭公差是难以实现，以及长期薄预测时应不是可能的，但是，设计的老板，削弱和插入。最起码的核心孔径 可取的铝， 3 | 16-1 | 4 英寸 ；和最低节厚度最好是铝， 3 |一六英寸 ；库珀， 3 |三十二英寸 ；铁， 3 | 32 英寸 ；镁， 5 | 332 中 ；和钢铁， 1 | 4-1 |二英寸 2 干砂过程是类似的绿色砂工艺，但核心方块代替模腔。这种方法通常仅限于一些小的部分比方法 1 。沙子是保税的设置粘结剂，其核心是然后烤箱烘焙300-400 删除水分。 3 二氧化碳砂过程是一个砂铸模的保税白衣硅酸钠的解决方案和设置，迫使二氧化碳气体通过沙子。这种类型的模具是强有力的，并允许生产更好地控制铸件尺寸比方法 1 或 2 。 4 核心砂型过程是在模具把完全从烤箱烤内核设置与有机粘结剂如石油或。 壳型铸造。这是一个过程，模具是由涂层砂的热固性塑料。模具然后支持对的沙子或枪杀，和熔融金属倒入。当金属凝固，模具是脱离成品铸件。 壳牌成型生产铸件表面光滑，颗粒均匀的结构，尺寸精度高，快速的生产速度和最低数量的精加工工序。最低节浇注是 1 | 16-1 |四英寸但部分差异的最高最低比例大于 5 至 1 月应当避免。老板，削弱和插入很容易演员，和最小芯孔直径为 1 | 8-1 | 4 英寸该方法是比较昂贵的是仅限于少数金属。 全金 属型铸造。在这一进程中一个绿色沙子或冷战设置树脂包装约泡沫塑料模式（例如，聚苯乙烯） 。塑料格局蒸发与浇注的熔融金属的模具。一种改进铸件表面可通过把一个难治型的涂层表面的格局面前砂包装。格局可一件或几件，这取决于复杂的部分。 塑料的处理方式很容易。它们不需要任何决议草案，并没有闪光的生产铸件。对于小批量的生产这种方法可以是昂贵的，这取决于项目的规模和复杂的铸件。建议的最低部分厚度为 0 0.1 英寸，最大切片厚度是无限的。老板，削弱，并插入本没问题这种类型的铸造。最低芯孔直径为 1 |四英寸 永久模铸件。 这些都是由一个模具，可以反复使用。一些应用程序已经报告多达25 000 件是由相同的模具。通常情况下，模具需要一些纠正后，约 3000 用途。模具是机械加工的金属（例如，灰口铸铁）铸造有色金属。加工石墨模具用于铸钢。 这种方法生产铸件具有良好的表面光洁度，以及良好的晶粒结构，低孔隙度，高尺寸精度。最初的模具成本比较昂贵，但铸件重量只有几盎司，至铸件限于相对简单的形状并建议第最大厚度约为二