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

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 IntroductionManufacturing 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 productThe 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 techniques12 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 castings1 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 aluminum3 1614 in and the minimum section thicknesses advisable are aluminum 316 in cooper 332 in iron 332 in magnesium5332 in and steel 1412 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 3The 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 11614 in but section differences where the imum 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 1814 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 imum section thickness is unlimited Bosses undercuts and inserts present no problem in this type of casting The minimum cored hole diameter is 14 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 imum recommended section thickness is about 20 in The minimum thickness however dependsuoon the material being cast as follows 316 in for iton 33218 in for aluminum 532 in for magnesium and 332 516 in for copper The minimum castable holes are 31614 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 imum wall section thickness is usually restricted to 316 in but certainly to no greater than 050 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 0040-0060 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 0025-0050 in There is however no limit to the imum 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 castingThe technique of investment casting requires careful workmanship and expensive patterns and moths The minimum castable wall thickness is about 0025-0050 in and the imum 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 fallsthrough 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 12 in and the imum size is about 9 in 译文铸造和铸造过程 11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 二级进程是那些把局部的尺寸和外表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外表处理的耐腐蚀硬度和外表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12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根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稳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局部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外表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局部比方法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 壳牌成型生产铸件外表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 四英寸但局部差异的最高最低比例大于5至1月应当防止老板削弱和插入很容易演员和最小芯孔直径为1 8-1 4英寸该方法是比拟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良铸件外表可通过把一个难治型的涂层外表的格局面前砂包装格局可一件或几件这取决于复杂的局部 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工程的规模和复杂的铸件建议的最低局部厚度为0 01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外表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本钱比拟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点英寸的最小厚度材料被抛如下 3 十六英寸的iton 3 32-1 8英寸为铝 5 32英寸的镁以及3 32 -5 16英寸对铜最低浇注洞3 16-1 四英寸的直径压铸的过程中广泛使用的数量型生产错综复杂锌铝铅镁合金方法是有限的使用锡和铜合金 铸件形成迫使熔融金属压力下的1500至1525年为000磅精确加工钢模具钢铁死亡这是水冷是一起举办了水压机直到金属铸件县稳固 以减轻弹射的演员局部润滑剂是喷涂成型模具外表和弹射引脚对于小型压铸部件 多腔模具的使用的外表光洁度由此产生的顺利具有良好的尺寸精度尽管生产本钱的价格相对廉价最初的模具本钱就很高压铸限于有色金属和大小的局部可演员墙节的最大厚度通常仅限于3 16英寸但肯定不超过050英石膏型铸造 这些都是由浇注1有色合金例如铝铜或锌合金为石膏模具然后打破删除凝固铸造铸件生产的这一进程的顺利进行具有尺寸精度上下孔隙度并可以在许多错综复杂的方法不过缺点是仅限于有色金属小件也需要相对较长的时间使模具最低墙厚度0040-0060节的为铸造领域小于2平方米在对于较大的铸造领域最小壁厚增加 逸夫过程中兴旺国家在过去十年中是一个有希望的方法本钱员工使用石膏模具此过程铸件生产与罚款和尺寸精度和良好的外表光洁度 陶瓷型铸造 这个过程使用的模具制成的陶瓷粉末粘结剂和胶凝剂模具也可以陶瓷面临加强与沙子的支持该方法仅限于铸造复杂的局部需要细节密切公差并顺利完成最小壁厚建议是0025-0050 但没有限制的最大壁厚熔模铸件 这是取得理想时局部有复杂的形状具有良好的外表光洁度并需要高度的尺寸精度此外这种方法铸造允许使用各种不同的金属合金没有此外这种方法的铸造允许使用各种不同的金属合金并没有任何金属闪光被遣送完成铸造 技术精铸需要仔细的做工和昂贵的模式和飞蛾最低浇注壁厚约0025-0050英寸最大厚度不应超过3英寸 离心铸造 这是一个方法铸造形状的熔化金属的身份进入一个旋转载模具模具是沙子金属或石墨取决于金属铸造 并旋转轴中心对他们无论是在一个水平或垂直位置 比拟大的直径和笨重的部件都被管枪管空心轴机械驱动器卷长袖油管等凡直径长度比例是相当大的旋转轴可垂直安装模具在方法被称为铸造这是用来制造部件如车轮隔膜磁盘飞轮等图1-5-2显示原理局部的芯铸造的飞轮一般来说离心铸造法是昂贵的也是有限的形状可演员然而铸件作出这一mehod都非常健全有良好的尺寸精度还应当指出这种方法是唯一的出路获得一个大圆筒的一局部 连续铸造 这是一个方法即熔融金属不断严重性美联储从包成锭模的形状是开放的两端由于金属瀑布 通过模具它的形状并正在迅速冷却喷水然后将具体的长度 连铸工艺的优点在于本钱低和具有较高的生产此外这种方法允许铸造材料不能挤压然而连续铸造仅限于形状的截面即方向铸造 该最小壁厚取决于形状被演员的最小尺寸的铸造是1 2英寸和的最大尺寸是九英寸