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焊接专业英语课文翻译

时间:2021-06-19 19:37:36 翻译 我要投稿

焊接专业英语课文翻译

  焊接技术与工程专业一般对于中专技校生而设置,培养适应焊接生产、管理、服务第一线需要的,德、智、体、美等方面全面发展的专业人才。下面小编为大家带来焊接专业英语课文翻译,希望对大家有帮助!

焊接专业英语课文翻译

  1.Pattern Material

  Wood is the most common material for patterns. It is easy to work and readily available. Properly selected and kiln-dried mahogany, walnut, white pine, and sugar pine are often used. Sugar pine is most often used because it is easily worked and is generally free from warping and cracking. Moisture in the wood should be about 5 to 6% to avoid warping, shrinking, or expanding of the finished pattern.

  Metal patterns may be loose or mounted. If usage warrants a metal pattern, then the pattern probably should be mounted on a plate and include the gating system. Metal is used when a large number of castings are desired from a pattern or when conditions are too severe for wooden patterns. Metal patterns wear well. Another advantage of a metal pattern is freedom from warping in storage. Commonly a metal pattern is itself cast from a master pattern and can be replaced readily if damaged or worn.

  Patterns are made of plaster and plastics. Plaster patterns are easy to make; they can be cast where original molds are available. However, plaster is brittle and not suitable for molding large numbers of sand castings. Plastics serve in several ways for pattern making. Some conventional patterns are made of abrasion-resistant plastics with cost and durability between wood and metal. Another use of certain plastics is to make emergency patterns quickly or to salvage worn or broken patterns.

  1.模型材料

  木板是常用的材料,很容易去做并且很通用,普通的选择是桃花芯木,胡桃木,白松和糖松。糖松是最常用的,很容易去制作而且很容易收缩和开裂很自如。在完成的模型中水分应控制在5%-6%之间为防止变形、收缩、膨胀。

  金属模型可能是实体的或模板的,模型可能被铸造在一个金属板上,包括浇注系统。当大量的铸件都特别需要一个模型,或者条件非常严格时,就要用金属,金属模板的耐磨性很好。另一个优点是它不受储藏变形的限制。一般来说,金属模板由一个主要模板铸造而成,如果它被损坏或磨损了也很容易被替代。

  模板由石膏和塑料制成。石膏模板很容易制作,它们可以被制作当原始铸型,然而,石膏是容易损坏的,并且不适合于数量多的砂型铸造,塑料在模板制作中可以有很多方式,一般现用的模板都由持久磨损的塑料和介于木头和金属之间的耐磨材料制成。塑料的另一种用途是能快速做成应急模板或者用旧的或者破损的模板。

  2.Cleaning , Finishing Castings

  After solidification and removal from the molds, most castings require some cleaning and finishing. These may involve all or several of the following steps:

  1. Removing cores.

  2. Removing gates and risers.

  3. Removing fins and rough spots from the surface.

  4. Cleaning the surface.

  5. Repairing any defects.

  The required operations are not always done in the same order, and the particular casting process may eliminate some of them. Because cleaning and finishing operations may involve considerable expense, some consideration should be given to them in designing castings and in selecting the casting method to be used. Often substantial savings can be effected. In recent years much attention has been given to mechanizing these operations.

  Sand cores usually can be removed by shaking. Sometimes they must be removed by dissolving the core binder. On small castings, gates and risers can often be knocked off. However, on large castings, and often on small castings, they must be cut off, On nonferrous and cast iron castings this usually is done by means of an abrasive cutoff wheel, power hacksaw or bandsaw. Gates and risers on steel castings, especially large ones, are often removed by an oxyacetylene torch.

  After the gates and risers are removed, small castings are often put through tumbling barrels, to remove fins, snags, and sand that adhere to the surface. Tumbling also may be used to remove cores and, in some cases, gates and risers. Frequently, some type of shot or slug material is added to the barrel to aid in the cleaning. Larger castings may be passed through a cleaning chamber on a conveyor, wherein they are subjected to blasts of abrasive or cleaning material. Large castings usually have to be finished manually, using pneumatic chisels, portable grinders, and manually directed blast hoses in separate cleaning rooms.

  Although it is desirable that casting contain no defects, it is inevitable that some will occur, particularly in large castings where only one or a few of a particular design are made. Some types of defects can be repaired readily and satisfactorily by arc welding. However it is imperative that the casting be of a material that can be welded satisfactorily, that all defective areas be removed down to sound metal by grinding, or chipping, and that a sound repair weld be made.

  2.清洗,整理铸件

  凝固后、清除模具,大多数铸件需要一些清洁和整理活动。这些可能涉及所有或几个下列步骤。

  1.移除内核。

  2.移除浇注系统和冒口。

  3.移除表面飞边和粗糙点。

  4.清理表面。

  5.修理所有缺陷。

  在相同的顺序中所需的行动并不总是要做,特别是铸造工艺可以消除其中的一些。由于清洁和整理的行动可能涉及相当大的开支,在设计和选择铸件的铸造方法使用方面应该给与一些考虑。往往可以获得大量节省。近年来,更多的注意力已经放在机械化去进行这些行动。

  通过摇晃砂芯通常可以去除。有时 ,他们必须通过解散砂心粘结剂来去除。小铸件,浇注系统和冒口往往可以被打掉。然而,在大型铸件以及小铸件,他们必须切断。对于非铁金属铸件和铸铁件的浇注系统与冒口,一般用切割砂轮、电动弓锯或带锯去除。钢铸件的阀门和立管,尤其是大企业,往往是通过氧乙炔火焰来去除。

  浇注系统和冒口去除以后,通常将小型铸件放入清理滚筒内,以去除飞边、毛刺和铸件表面上的粘砂。滚筒也可用于消除内核,在某些情况下,浇注系统和冒口。经常地,某些类型的炮弹或星铁材料被添加到圆桶以协助清理。较大的铸件可通过清理室的传送带,在那里他们受到研磨料的喷射或清洗材料。较大的铸件通常都必须手工完成,采用气动凿子,便携式磨床,并在单独清洗室手动指示喷砂胶管。

  尽管铸件不含缺陷是令人期望的,但是不可避免有些缺陷也会发生,特别是在大型铸件,只有一个或几个特定设计的意见。通过弧焊某些类型的缺陷可以容易地修复和令人满意的。然而,当务之急是铸造一种材料,可以令人满意地进行焊接,通过磨光、削可以将有缺陷的区域被删除成为优质金属,而且优质的焊接修补可以进行。

  3.Sand Conditioning and Control

  Sand used to make must be carefully conditioned and controlled in order to give satisfactory and uniform results. Ordinary silica(SiO2), zircon, or olivine ( forsterite and fayalite ) are compounded with additives to meet four requirement:

  1. Refractoriness: the ability to withstand high temperatures.

  2. Cohesiveness (referred to as bond): the ability to retain a given shape when packed in a mold.

  3. Permeability: the ability to permit gases to escape through it.

  4. Collapsibility: the ability to permit the metal to shrink after it solidifies.

  Refractoriness is provided by the basic nature of the sand. Cohesiveness, bond, or strength is obtained by coating the sand grains with clays, such as bentonite, kaolin or illite, that become cohesive when moistened. Collapsibility is obtained by adding cereals or other organic materials such as cellulose, that burn out when exposed to the hot metal, thereby reducing the volume of solid bulk and decreasing the strength of the restraining sand. Permeability is primarily a function of the sand particles, the amount and types of clays or other bonding agents, and the moisture content.

  Sand control. Although sand control is of concern to the designer of castings, it is a matter of great concern to the foundry worker, who is expected to deliver castings of good and consistent quality.Standard tests and procedures have been developed to maintain consistent sand quality by evaluating grain size, moisture content, clay content, mold hardness, permeability, and strength.

  Grain size is determined by shaking a known amount of dry silica grains downward through a set of 11standard sieves having increasing fineness. After shaking for 15 minutes, the amount remaining in each sieve weighed, and the weights are converted into an AFS number.

  Moisture content most commonly is determined by a special device which measures the electrical conductivity of a small sample of sand that is compressed between two prongs. Another device provides a continuous measure of the moisture content, by emission from a radioactive source, as the sand passes along a conveyor belt. A third method is to measure the direct weight loss from a 50-gram sample when it is subjected to a flow of air at about 110℃for 3 minutes.

  Clay content is determined by washing the clay from a 50-gram sample of molding sand in water that contains sufficient sodium hydroxide to make it alkaline. After several cycles of agitation and washing in such a solution, the clay will have been removed. The remaining sand is dried and then weighed to determine the proportion of the original sample that was clay.

  3.砂处理和控制

  砂用于制造铸型必须仔细调节和控制以提供满意的服务和统一的结果。普通石英(二氧化硅),锆石,或橄榄石(镁橄榄石和铁橄榄石)加上添加剂以满足四个要求:

  1.耐火度:耐高温能力。

  2.凝聚力(称为债券):能够保留一个给定的形状时,装在一个模具的能力。

  3.透气性:允许气体逸出的能力。

  4.退让性:金属凝固后收缩的能力。

  耐火度是沙子的基本性质。型砂的强度是靠包覆在砂粒表面的粘土,如膨润土、高岭土或伊利石加水后具有粘性而获得的。退让性是通过添加谷物或其他有机材料获得,如纤维素,当暴露在热金属会烧毁,从而减少了固体散装的体积和降低抑制砂的强度。透气性是砂颗粒的主要功能,数量和粘土的类型或其他粘合剂和含水量。

  防砂。尽管防砂是设计师关注的铸件,是铸造工人所关注的`问题,他们被期望输送优良和统一质量的铸件。标准测试程序已经发展到由晶粒的大小,水分含量,粘粒含量,模具的硬度,透气性和强度来评价保持一致的砂的质量。

  原砂粒度组成的测定方法,是把一定数量的干硅砂试样放在一套标准筛上进行筛分,而标准筛是由十一个越来越细的筛子构成的。摇后15分钟,称量剩余在每个筛子里面的数量,权重转化为AFS数。

  含水量最常见的是由一个特殊的装置决定的,测量一个被压缩在两个尖头叉子小样本沙子的电导率。另一个装置提供了一种可以连续测量含水量,通过发射从放射性源,如砂沿着输送带。第三种方法是从50克样品中,当它在大约110℃进行3分钟流动的空气中直接测量减少量。

  粘土含量是由在水中洗粘土从50克样品的型砂含有足够的氢氧化钠使其碱性决定的。在这种解决方案中,经过几个周期的搅拌和清洗,粘土已被移除。剩下的砂干燥,,然后称重以确定原样品粘土的比例。

  4.Investment Casting

  Investment casting actually is a very old process. It existed in china for centuries, and Cellini employed a form of it in Italy in the sixteenth century. Dentists have utilized the process since 1897, but it was not until World War II that it attained industrial importance for making jet turbine blades from metals that were not readily machinable. Currently millions of castings are produced by the process each year, its unique characteristics permitting the designer almost unlimited freedom in the complexity and close tolerances he can utilize.

  Investment casting involves the following steps:

  1. Produce a master pattern.

  2. From the master pattern, produce a master die.

  3. Produce the wax patterns.

  4. Assembly the wax patterns to a common wax sprue.

  5. Coat the cluster with a thin layer of investment material.

  6. Produce the final investment around the coated cluster.

  7. Vibrate the flask to remove the entrapped air and settle the investment material around the cluster.

  8. Allow the investment to harden.

  9.Melt or dissolve the wax pattern to permit it to run out of the mold.

  10.Preheat the mold preparatory to pouring.

  11.Pouring the molten metal.

  12.Remove the castings from the mold.

  Fig.3-7-5 schematically shows the investment procedure wherein the investment-mold material fills the entire

  Fig.3-7-5  Investment flask-casting procedure

  4.熔模铸造

  熔模铸造实际上是一个非常古老的铸造过程。它在中国存在了几个世纪,在十六世纪的意大利,赛里尼铬锰钢就以熔模铸造的一种形式被制造。自从1897年以来,牙医就已经利用了这个程序,但直到第二次世界大战期间,它在工业制造中获得一定的重要地位,从金属不易加工到加工制造喷气涡轮叶片目前每年数以万计的铸件通过这个过程被生产出来,其独特的特点就是允许设计者在复杂性和公差方面几乎可以无限制地利用。

  熔模铸造包括以下步骤:

  1.产生一个主模式。

  2.从主模式,产生一个主模。

  3.产生蜡模式。

  4.装配到一个共同的蜡型浇口。

  5.外套集群有一层薄薄的铸模材料。

  6.在涂覆集群生成最终的铸模。

  7.在模组的周围,振动长颈瓶移除裹入的气体和处理熔模材料。

  8.允许熔模变硬。

  9.熔融或溶解蜡模式允许它脱离出模具。

  10.预热模具准备浇注。

  11.浇注熔融金属。

  12.从模具中移出熔模。

  图3-7-5示意图显示了铸造过程中,熔模铸型材料充满了整个瓶子。

  5.Patterns

  A pattern is a form used to prepare and produce a mold cavity. It is another tool in the hands of a founder. It has been said that a poor casting may be produced from a good pattern, but a good casting will not be made from a poor pattern.

  The designer of a casting must look forward to the pattern to assure economical production. The design should be as simple as possible to make the pattern easy to draw from the sand and avoid more cores than necessary.

  Types of patterns. Many molds are made from loose patterns. Such a pattern has essentially the shape of the casting with perhaps forms for sprues, risers, etc, attached. This is the cheapest pattern to make but the most time consuming to use. A loose pattern may be made in one or more pieces. For instance, a two-piece pattern is normally split into cope and drag parts to facilitate molding. For a part difficult to mold, some loose pieces may be removable to allow the pattern to collapse for withdrawal from the sand that would otherwise not be possible.

  Patterns fastened permanently to a board or match plate are known as mounted patterns. A main advantage is that a mounted pattern is easier than a loose pattern to use and store. Another advantage is that the gating system can be mounted on a match plate, and thus the time required to cut the gating system in the mold can be eliminated. Mounted patterns cost more than loose patterns, but when many castings are to be made from a pattern, the time saved in operation warrants the cost of mounting the pattern.

  A core box is essentially a type of pattern into which sand is rammed or packed to form a core as illustrated in

  Fig.3-2-1 Typical core boxes

  Symmetrical molds and cores, particularly in large sizes, are sometimes shaped by means of sweeps as illustrated in Fig.3-2-2. The sweep is a flat board with an outline of the cross section of the part to be made and is revolved around a central axis to clear away excess sand inside the mold.

  Fig.3-2-2  Sweep pattern

  5.模型

  模样是用来形成铸件型腔的工艺装备它是铸工手中的另一个工具,据说质量差的铸件有可能是由一个好的铸件制造的,但是好的铸件绝不是由差的铸件制造而成的。

  铸件的设计者希望模样可以确保生产成本。设计要尽可能简单,以便于起模,而且要避免使用过多的型芯。

  模样的类型。很多模具都是由实体模铸成的。一个模型有基本的铸件形状并附有浇道、冒口等其它铸件。这是铸造花费最便宜的模型,但是时间花费很多。一个实体模型可以由一个或多个部分组成。例如,两箱式模型可以裂开以便于起模,对于用其它方法难以造型的零件。为了能从型砂中取出模样,可将整体模样局部做成一些活块,以便于起模。

  模样固定永久地在木板上或双面模板就是我们熟知的模板,与单体模相比,模板的一个主要优点是容易使用和存放。另一个优点是浇注系统可以消除,模板要比实体模花费的要多,但是当批量生产时,节约了大量的操作。

  芯核本质上也是模样的一种,用沙子填塞或充满型芯例如插图Fig3-2-1。

  对称的模型和型芯,尤其是大尺寸的。有时通过刮板的方法制造成型如插图Fig3-2-2。刮板即平板,与大纲的横截面的部分制造而成和绕着中心轴使旋转去清除大量的在子模型里面的沙子。

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