材料成型及控制工程专业英语-12.WELDING TECHOLOGY

1、2009 Hisuntech Corp.CHAPTER 12 WELDING TECHOLOGY- - 1 1 - - - 2 2 - -CHAPTER 12 WELDING TECHOLOGYpWelding is a process in which two materials, usually metals, are permanently joined together through localized coalescence, resulting from a suitable combination of temperature, pressure, and metallurgi

2、cal conditions.p焊接是将两种材料，一般为金属材料，在适当的温度、压力焊接是将两种材料，一般为金属材料，在适当的温度、压力和冶金条件下，通过局部融合，被永久地连接在一起的一种和冶金条件下，通过局部融合，被永久地连接在一起的一种工艺过程。工艺过程。 localized 局部的；小范围的局部的；小范围的coalescence metallurgical 冶金的冶金的- - 3 3 - -CHAPTER 12 WELDING TECHOLOGYpBecause the combination of temperature and pressure can range from high

3、 temperature with no pressure to high pressure with no increased temperature, welding can be accomplished under a very wide variety of conditions, and numerous welding processes have been developed and are used routinely in manufacturing. p由于温度和压力的组合的范围很广，可以从高温不加压，到由于温度和压力的组合的范围很广，可以从高温不加压，到高压力不加热均可

4、，因此焊接可以各种条件下实现，目前已高压力不加热均可，因此焊接可以各种条件下实现，目前已经发展了许多焊接工艺，它们通常用于在加工制造中。经发展了许多焊接工艺，它们通常用于在加工制造中。numerous 许多的，很多的许多的，很多的routinely 通常地；常规地通常地；常规地- - 4 4 - -CHAPTER 12 WELDING TECHOLOGYpThe average person usually has little concept of the importance of welding as a manufacturing process, yet a large propor

5、tion of our metal products would have to be drastically modified, would be considerably more costly, or could not perform as efficiently, if it were not for the use of welding.p一般人通常没有认识到焊接作为制造工艺的重要性，但如果一般人通常没有认识到焊接作为制造工艺的重要性，但如果不采用焊接技术，我们的金属产品的很大一部分将不得不大不采用焊接技术，我们的金属产品的很大一部分将不得不大幅修改，或将相当多的昂贵，或者无法高效

6、运转。幅修改，或将相当多的昂贵，或者无法高效运转。concept 观念，概念观念，概念drastically 彻底地彻底地- - 5 5 - -CHAPTER 12 WELDING TECHOLOGYpTo obtain coalescence between two metals, there must be a combination of sufficient proximity and activity between the atoms of the pieces being joined to cause the formation of common metallic cryst

7、als.p以获得两个金属间的融合，就必须要求两个被连接的工件的以获得两个金属间的融合，就必须要求两个被连接的工件的原子具有足够的距离和活性，以能使他们形成共同的金属晶原子具有足够的距离和活性，以能使他们形成共同的金属晶体。体。proximity 邻近；接近邻近；接近 activity 活度，活性活度，活性common 共同的共同的- - 6 6 - -CHAPTER 12 WELDING TECHOLOGYpThe ideal metallurgical bond requires: (1) perfectly smooth, flat or matching surfaces; (2) cl

8、ean surfaces, free from oxides, absorbed gases, grease, or other contaminants; (3) no impurities be present within the metals; and (4) that both metals be single crystals with identical crystallographic orientation.p理想的冶金结合需要：（理想的冶金结合需要：（1）完全光滑的，平坦的或匹配的）完全光滑的，平坦的或匹配的表面表面; （2）表面清洁，无氧化膜，没有吸收气体，油脂或其）表面

9、清洁，无氧化膜，没有吸收气体，油脂或其他污染物他污染物; （3）金属之间无杂质存在）金属之间无杂质存在;（4）无论是金属的单）无论是金属的单晶具有相同的晶体取向。晶具有相同的晶体取向。identical 同一的；完全相同的同一的；完全相同的crystallographic orientation 晶向晶向- - 7 7 - -CHAPTER 12 WELDING TECHOLOGYpObviously, these conditions are difficult to obtain, even under ideal conditions, and are impossible under

10、normal conditions. Consequently, the various joining methods are designed to overcome or compensate for the inability to achieve ideal conditions.p显然，这些条件即使在理想的条件下也很难获得，在正常条显然，这些条件即使在理想的条件下也很难获得，在正常条件下是不可能的。因此，人们设计了各种接合方法来克服或件下是不可能的。因此，人们设计了各种接合方法来克服或补偿无法实现理想的条件。补偿无法实现理想的条件。Consequently 因此；结果因此；结果co

11、mpensate 补偿，赔偿；抵消补偿，赔偿；抵消- - 8 8 - -CHAPTER 12 WELDING TECHOLOGYpThe various welding processes not only differ considerably in the manner in which temperature and pressure are combined and achieved, they also vary as to the attention that must be given to the cleanliness of the metal surface prior t

12、o welding and to possible oxidation or contamination of the metal during welding.p各种焊接工艺中各种焊接工艺中,不仅温度和压力相结合方式和获取方式大不不仅温度和压力相结合方式和获取方式大不相同，而且必须考虑的焊接前金属表面的清洁和焊接过程中相同，而且必须考虑的焊接前金属表面的清洁和焊接过程中可能的氧化和污染也不相同。可能的氧化和污染也不相同。oxidation 氧化氧化contamination 污染，玷污；污染物污染，玷污；污染物- - 9 9 - -CHAPTER 12 WELDING TECHOLOGYpI

13、f high temperatures are used, most metals are affected more adversely by the surrounding environment and, if actual melting occurs, serious modification of the metal may result. p由于温度和压力的组合的范围很广，可以从高温不加压，到由于温度和压力的组合的范围很广，可以从高温不加压，到高压力不加热均可，因此焊接可以各种条件下实现，目前已高压力不加热均可，因此焊接可以各种条件下实现，目前已经发展了许多焊接工艺，它们通常用于

14、在加工制造中。经发展了许多焊接工艺，它们通常用于在加工制造中。numerous 许多的，很多的许多的，很多的routinely 通常地；常规地通常地；常规地- - 1010 - -CHAPTER 12 WELDING TECHOLOGYpAlso, the metallurgical structure and, quality of the metal may be affected-usually adversely-as a consequence of the heating and cooling, and these effects should be taken into acc

15、ount.p此外，由于加热和冷却的原因，金属的金相结构和质量会受此外，由于加热和冷却的原因，金属的金相结构和质量会受到影响，这些影响通常是不利的，并且这些作用应予以考虑。到影响，这些影响通常是不利的，并且这些作用应予以考虑。metallurgical 金相的，冶金的金相的，冶金的adversely 不利地不利地- - 1111 - -CHAPTER 12 WELDING TECHOLOGYpIn summary, in order to obtain satisfactory welds it is desirable to have a satisfactory heat and/or pr

16、essure source, a means of protecting or cleaning the metal, and avoidance of, or compensation for, harmful metallurgical effects.p总之，为了获得满意的焊缝，需要有具有令人满意的热源和总之，为了获得满意的焊缝，需要有具有令人满意的热源和/或压力源，保护或清洁金属的有效手段，和避免或补偿有或压力源，保护或清洁金属的有效手段，和避免或补偿有害的冶金作用。害的冶金作用。welds 焊缝焊缝compensation 补偿，赔偿；抵消补偿，赔偿；抵消CHAPTER 12 WEL

17、DING TECHOLOGY- - 1212 - - - 1313 - -CHAPTER 12 WELDING TECHOLOGYpOxyacetylene welding (OAW) is a process by which coalescence is achieved by heating a workpiece with flame produced by the combination of oxygen and acetylene gases. The process may be used with or without pressure or filler materials

18、. p氧乙炔焊接（氧乙炔焊接（OAW）是通过用氧气和乙炔气体的混合火焰）是通过用氧气和乙炔气体的混合火焰来加热的工件，以实现材料连接的工艺。该工艺可用加压或来加热的工件，以实现材料连接的工艺。该工艺可用加压或不加压，用或者不用填充材料。不加压，用或者不用填充材料。coalescence 合并；联合；接合合并；联合；接合acetylene gases 乙炔气乙炔气- - 1414 - -CHAPTER 12 WELDING TECHOLOGYpOAW is the most widely used oxyfuel method, whose flame is hotter than the fl

19、ame of any other common gas and is the only one of sufficient temperature to gas-weld many alloys.p氧乙炔焊接是最广泛使用的氧的方法，其火焰是比任何其它氧乙炔焊接是最广泛使用的氧的方法，其火焰是比任何其它常见气体的火焰温度都高，是唯一具有足够的温度以气体焊常见气体的火焰温度都高，是唯一具有足够的温度以气体焊接合金的气体。接合金的气体。oxyfuel 气焊气焊flame 火焰火焰- - 1515 - -CHAPTER 12 WELDING TECHOLOGYpThe welding process

20、is illustrated in Fig. 12. 1. With the workpieces in position the flame is directed at the joint. The welder holds the torch in one hand and the filler metal in the other. When the flame has melted a small amount of the base metal, the end of the filler metal is placed in the pool of molten metal.p焊

21、接过程如图焊接过程如图12.1所示。把工件置于适当的位置，火焰冲着所示。把工件置于适当的位置，火焰冲着接头。焊工一手拿着焊枪，另一只手拿着填充金属。当火焰接头。焊工一手拿着焊枪，另一只手拿着填充金属。当火焰熔化少量的基体金属的时候，填料金属的端部被放置在熔融熔化少量的基体金属的时候，填料金属的端部被放置在熔融金属池中。金属池中。illustrate 图解图解torch 焊枪焊枪- - 1616 - -CHAPTER 12 WELDING TECHOLOGYpAs the base metal and filler metal melt and flow together, the torch

22、and filler metal are moved slowly along the joint. The puddle then cools and forms a continuous bead of solid weld metal. If more than one bead is needed for joints in thick material, filler metal is deposited on top of the previous beads until the weld is completed.p随着基体金属和填充金属一起熔化并流动，焊枪和填充金属随着基体金属

23、和填充金属一起熔化并流动，焊枪和填充金属都沿着接头慢慢移动。然后都沿着接头慢慢移动。然后熔池熔池冷却并形成固体焊缝金属的冷却并形成固体焊缝金属的连续焊道。如果在焊接厚材料时需要一个以上的焊道时，填连续焊道。如果在焊接厚材料时需要一个以上的焊道时，填料金属上堆积在前一焊道上，直到焊接完成。料金属上堆积在前一焊道上，直到焊接完成。puddle 熔池熔池 bead 焊道焊道deposite 沉淀，堆放，堆积沉淀，堆放，堆积- - 1717 - -CHAPTER 12 WELDING TECHOLOGYpOxyacetylene welding can be done in all of the st

24、andard positions (flat, vertical, horizontal, and overhead). Thin material is sometimes joined without using filler metal. The faying surfaces are heated with the torch until they melt and flow together.p氧乙炔焊接可以在所有的标准位置来完成（平，立，横，氧乙炔焊接可以在所有的标准位置来完成（平，立，横，仰）。薄料的焊接有时不使用填充金属。接合面用焊枪加热，仰）。薄料的焊接有时不使用填充金属。接

25、合面用焊枪加热，直到它们融化和流动起来。直到它们融化和流动起来。faying surfaces 搭接面搭接面- - 1818 - -CHAPTER 12 WELDING TECHOLOGYpFluxes used with Oxyacetylene welding are pastes that are brushed on the base-metal and filler metal. During welding, the flux melts and floats on top of the molten weld metal to prevent air from contactin

26、g the metal.p氧乙炔焊接所用助焊剂是浆料，它们被刷在基体金属和填充氧乙炔焊接所用助焊剂是浆料，它们被刷在基体金属和填充金属上。焊接时焊剂熔化，浮在熔融焊接金属的表面，以防金属上。焊接时焊剂熔化，浮在熔融焊接金属的表面，以防止空气从金属接触。止空气从金属接触。pastes 膏；糊状物膏；糊状物- - 1919 - -CHAPTER 12 WELDING TECHOLOGYpAnother important function of the flux is to clean the base metal to permit more thorough wetting of the so

27、lid metal by the molten weld metal. The flux solidifies with the weld metal and is scraped or wire-brushed off after the joint is completed. p焊剂的另一个重要功能是清洁的基体金属，使固体金属被熔焊剂的另一个重要功能是清洁的基体金属，使固体金属被熔融焊缝金属更彻底地润湿。焊剂与焊缝金属一起凝固，最后融焊缝金属更彻底地润湿。焊剂与焊缝金属一起凝固，最后在接头成形后被刮掉或用钢丝刷刷净。在接头成形后被刮掉或用钢丝刷刷净。thorough 彻底的；十分的彻底的；

28、十分的 wetting 浸润，润湿浸润，润湿scraped 刮掉刮掉 wire-brushed用钢丝刷刷净用钢丝刷刷净- - 2020 - -CHAPTER 12 WELDING TECHOLOGYpSome materials can be oxyacetylene-welded without the use of flux; the burned gases from the torch are sufficient to protect the weld metal.p一些材料可以无需使用焊剂而进行氧乙炔焊接的，从焊枪出一些材料可以无需使用焊剂而进行氧乙炔焊接的，从焊枪出来的燃烧气体足

29、以保护焊缝金属。来的燃烧气体足以保护焊缝金属。- - 2121 - -CHAPTER 12 WELDING TECHOLOGYpOAW is a common welding method, and one in which the human welder has considerable control over the weld zone temperature, filler-metal deposition rates, shaping and positioning of the weld, and flame envelope direction. p氧乙炔焊接是一种常见的焊接方

30、法，在这种方法中，焊工可氧乙炔焊接是一种常见的焊接方法，在这种方法中，焊工可以很大程度上控制焊接区的温度，填充材料的金属的沉积速以很大程度上控制焊接区的温度，填充材料的金属的沉积速率，焊缝的成形和位置，以及火焰包围的方向。率，焊缝的成形和位置，以及火焰包围的方向。envelope 包裹，包围包裹，包围- - 2222 - -CHAPTER 12 WELDING TECHOLOGYpThese attributes make this gas welding method very versatile for field work, repairs and maintenance, and sh

31、ort production runs.p这些属性使这种气体焊接方法非常适用于野外作业，维修及这些属性使这种气体焊接方法非常适用于野外作业，维修及保养，以及小批量生产。保养，以及小批量生产。versatile 通用的，万能的通用的，万能的scfield work 现场（野外）作业现场（野外）作业CHAPTER 12 WELDING TECHOLOGY- - 2323 - - - 2424 - -CHAPTER 12 WELDING TECHOLOGYpMetal arc welding involves fusing the faying surface of workpiece, using

32、 temperatures of approximately 5,980 C (10,000 F) produced by an electric arc between an electrode and workpiece. p金属极电弧焊利用电极和工件之间的电弧所提供的大约金属极电弧焊利用电极和工件之间的电弧所提供的大约5980 C 的高温将工件的结合面熔化。的高温将工件的结合面熔化。fusing 熔化熔化 - - 2525 - -CHAPTER 12 WELDING TECHOLOGYpMetal are readily joined by a variety of arc weldin

33、g processes, all employing the arc to melt the edges of the work and the electrode or filler metal to form a pool of molten metal. A solid, continuous workpiece joint is created upon cooling.p金属可教容易地通过各种电弧焊接方法连接，所有这些方法金属可教容易地通过各种电弧焊接方法连接，所有这些方法都是采用电弧熔化的工作边缘和电极或填充金属，用以形成都是采用电弧熔化的工作边缘和电极或填充金属，用以形成熔融金属

34、池。随后熔融金属池冷却，形成一个坚实的，连续熔融金属池。随后熔融金属池冷却，形成一个坚实的，连续的工件接头。的工件接头。 readily 容易地容易地 electrode 焊条，电极，焊丝焊条，电极，焊丝 pool 熔池熔池- - 2626 - -CHAPTER 12 WELDING TECHOLOGYpIn most arc welding processes, the weld area is shielded to protect the molten metal from oxidizing. Such shielding is provided by the melting of t

35、he flux coating on the electrode, by a granular flux blanket which forms a cover of molten slag, or by an atmosphere of shielding gas. p在大多数电弧焊过程中，焊接区被隔离，以保护熔融金属不在大多数电弧焊过程中，焊接区被隔离，以保护熔融金属不被氧化。这样的隔离是通过以下的方式提供：在焊丝上的焊被氧化。这样的隔离是通过以下的方式提供：在焊丝上的焊剂涂层的熔化，粒状焊剂覆盖层形成的熔渣，或保护气体。剂涂层的熔化，粒状焊剂覆盖层形成的熔渣，或保护气体。shielded

36、 隔离的；屏蔽了的；防护的隔离的；屏蔽了的；防护的slag 熔渣熔渣- - 2727 - -CHAPTER 12 WELDING TECHOLOGYpShielding arcs produce cleaner and tougher welding joints. The techniques and attributes of the several arc welding processes emerge in the following paragraphs.p屏蔽电弧产生能使焊接接头更洁净，牢固。下面几段将介绍屏蔽电弧产生能使焊接接头更洁净，牢固。下面几段将介绍几种电弧焊接的过程及其

37、特征。几种电弧焊接的过程及其特征。- - 2828 - -CHAPTER 12 WELDING TECHOLOGYpShielded Metal Arc Welding (SMAW) is the most common of the arc welding processes, because of its wide range of metal joint application, and because it requires only relatively low-cost equipment. This method uses heat supplied by an electric

38、 arc generated between the piecework and a consumable electrode. See fig.12.2. p手工电弧焊（手工电弧焊（SMAW）是最常见的电弧焊工艺，这是由于其）是最常见的电弧焊工艺，这是由于其金属接头应用广泛，以及它的设备成本相对教低。该方法使金属接头应用广泛，以及它的设备成本相对教低。该方法使用的热源是工件和可熔电极之间产生的电弧。见图用的热源是工件和可熔电极之间产生的电弧。见图.12.2。Shielded Metal Arc Welding 手工电弧焊手工电弧焊consumable electrode 可熔电极可熔电极手工

39、电弧焊视频手工电弧焊视频- - 2929 - -CHAPTER 12 WELDING TECHOLOGYpThe electrode, which also serves as the filler metal, is a metal rod coated with a flux, which melts as the electrode is consumed. Part of the remainder forms a slag deposit on the weld as it cools. Both protect the molten metal from oxidation by

40、excluding air from the weldment.p电极同时也作为填充金属，它是涂有焊剂金属棒。焊剂并随电极同时也作为填充金属，它是涂有焊剂金属棒。焊剂并随着电极熔化被消耗。含有部分残余冷却后形成熔渣沉积于焊着电极熔化被消耗。含有部分残余冷却后形成熔渣沉积于焊缝的表面。这两部分都能通过从焊件排除空气保护熔融金属缝的表面。这两部分都能通过从焊件排除空气保护熔融金属不被氧化。不被氧化。rod 棒棒 weldment 焊件焊件 - - 3030 - -CHAPTER 12 WELDING TECHOLOGYpSMAW is a fast, very versatile process.

41、 Covered electrodes ranging from plain carbon to special alloy and stainless steels are available to make this process applicable to most steels.p手工电弧焊是一种快速，灵活的工艺。焊丝范围广，可以是手工电弧焊是一种快速，灵活的工艺。焊丝范围广，可以是普通碳钢到特殊合金钢和不锈钢均可，这使这项工艺适用于普通碳钢到特殊合金钢和不锈钢均可，这使这项工艺适用于大多数钢。大多数钢。- - 3131 - -CHAPTER 12 WELDING TECHOLOGY

42、pGas metal arc welding(GMAW) employs the heat of an electric arc between the workpiece and s consumable electrode that supplied the filler metal. See fig12.3. It is a type of gas shielded arc welding, and consequently no flux or coating is used on the filler metal. p气体保护金属极电弧焊（气体保护金属极电弧焊（GMAW）采用工件和金

43、属熔化电）采用工件和金属熔化电极之间的电弧来提供热量，同时熔化电极也作为填充金属。极之间的电弧来提供热量，同时熔化电极也作为填充金属。如图如图12.3。它是一种气体保护电弧焊，因此没有焊剂，填充。它是一种气体保护电弧焊，因此没有焊剂，填充金属也没有涂层。金属也没有涂层。Gas metal arc welding 气体保护金属极电弧焊气体保护金属极电弧焊MIG焊视频焊视频- - 3232 - -CHAPTER 12 WELDING TECHOLOGYpWelding takes place in an atmosphere of gas that shields the metal from t

44、he air. The process is often called MIG (for metal inert gas) welding.p保护气体隔绝空气，焊接在这种保护气氛下进行。保护气体隔绝空气，焊接在这种保护气氛下进行。 这种工这种工艺通常被称为艺通常被称为MIG（金属惰性气体）焊接。（金属惰性气体）焊接。- - 3333 - -CHAPTER 12 WELDING TECHOLOGYpThe advantage of this process are the comparatively clean welds because there is no slag to remove,

45、and the elimination of distortion because of low heat input in the weld area. p这种工艺的的优点是焊缝比较干净，因为没有熔渣，并且由这种工艺的的优点是焊缝比较干净，因为没有熔渣，并且由于在焊接区输入热量低，因此消除变形。于在焊接区输入热量低，因此消除变形。comparatively 比较地；相当地比较地；相当地elimination 消除；除去消除；除去 distortion 变形变形- - 3434 - -CHAPTER 12 WELDING TECHOLOGYpGas tungsten arc welding (

46、GTAW) is performed with the heat from an electric arc discharge between the workpiece and a nonconsumable electrode made of tungsten. See Fig.12.4. p气体保护钨极电弧焊（气体保护钨极电弧焊（GTAW）的热量来自工件和钨制成的）的热量来自工件和钨制成的非自耗电极之间的电弧放电。如图非自耗电极之间的电弧放电。如图12.4。Gas tungsten arc welding 气体保护钨极电弧焊气体保护钨极电弧焊 discharge 放电放电 TIG焊视频焊

47、视频- - 3535 - -CHAPTER 12 WELDING TECHOLOGYpThis process, like GMAW, is gas-shielded arc welding, where an atmosphere of inert gas is maintained around the arc and no flux is used. The process is often called TIG (for tungsten inert gas) welding. p这工艺与气体保护金属极电弧焊相似，是气体保护电弧焊，这工艺与气体保护金属极电弧焊相似，是气体保护电弧焊，这

48、种工艺中惰性气体维持在电弧周围并且不用焊剂。这种工这种工艺中惰性气体维持在电弧周围并且不用焊剂。这种工艺通常被称为艺通常被称为TIG（钨极惰性气体）焊。（钨极惰性气体）焊。inert 惰性的惰性的 - - 3636 - -CHAPTER 12 WELDING TECHOLOGYp Tungsten is used for the electrode because of its resistance to high temperature, and, because the electrode does not melt, the arc is extremely steady and can

49、 be accurately directed into the joint. This welding can be done with or without the use of filler metal.p钨具有耐高温性，被用作电极，由于电极不熔化，电弧是极钨具有耐高温性，被用作电极，由于电极不熔化，电弧是极其稳定的，并能准确地引导到接头。该焊接方法可以使用或其稳定的，并能准确地引导到接头。该焊接方法可以使用或不使用填充金属。不使用填充金属。steady 稳定的；不变的稳定的；不变的 - - 3737 - -CHAPTER 12 WELDING TECHOLOGYpEquipment f

50、or GTAW welding is similar to that used for GMAW welding. The electrode holder is connected to a supply of shielding gas, and the electric circuit is provided by cables that connect the workpiece and electrode to the power source.pGTAW设备与设备与GMAW焊接相类似。电极枪被连接到保护气焊接相类似。电极枪被连接到保护气体供给源上，并用电缆将工件和电极与电源相连，组

51、成电路。体供给源上，并用电缆将工件和电极与电源相连，组成电路。electric circuit 电路电路cables 电缆电缆 - - 3838 - -CHAPTER 12 WELDING TECHOLOGYpSubmerged arc welding (SAW) is flux-shielded arc welding, where the heat is furnished by an electric arc occurring between the workpiece and a consumable filler metal electrode. The weld metal is

52、 shielded from the air by granular flux that surrounds the arc.p埋弧焊（埋弧焊（SAW）是焊剂保护电弧焊，焊接热量是由工件和熔）是焊剂保护电弧焊，焊接热量是由工件和熔化填充金属电极之间产生电弧的提供的。焊缝金属被电弧周化填充金属电极之间产生电弧的提供的。焊缝金属被电弧周围的粒状焊剂包围，以隔绝空气。围的粒状焊剂包围，以隔绝空气。Submerged arc welding 埋弧焊埋弧焊 furnished 供应；装备供应；装备 埋弧焊视频埋弧焊视频- - 3939 - -CHAPTER 12 WELDING TECHOLOGYpSu

53、bmerged arc welding is similar to GMAW, in that filler wire is used as the electrode, and the wire is fed automatically into the joint. The method of shielding and the nature of the arc differ greatly, however. p埋弧焊类似于熔化极气体保护焊，在该工艺中充填金属被用埋弧焊类似于熔化极气体保护焊，在该工艺中充填金属被用作电极，并且焊丝自动送入焊接接头。但是埋弧焊和电弧焊作电极，并且焊丝自动

54、送入焊接接头。但是埋弧焊和电弧焊在本质上有很大的不同。在本质上有很大的不同。feed 进给进给 - - 4040 - -CHAPTER 12 WELDING TECHOLOGYpIn SAW, the faying surfaces along the joint are covered by a thick blanket of flux. Because the end of the electrode extends into the flux, the arc is not visible during welding. The SAW process is illustrated i

55、n Fig.12.5. The flux is designed to be a nonconductor of electricity when solid, but becomes a conductor when heated to the molten state.p在埋弧焊中，沿焊缝的接合面都覆盖着厚厚的焊剂层。因为在埋弧焊中，沿焊缝的接合面都覆盖着厚厚的焊剂层。因为焊丝的端部埋在焊剂下面，所以电弧在焊接过程不可见。焊丝的端部埋在焊剂下面，所以电弧在焊接过程不可见。SAW过程如图过程如图12.5所示。焊剂固体时是电的非导体，但是当所示。焊剂固体时是电的非导体，但是当加热至熔融状态变成

56、导体。加热至熔融状态变成导体。visible 看得见的看得见的nonconductor 绝缘体绝缘体 - - 4141 - -CHAPTER 12 WELDING TECHOLOGYpThe SAW process is the most often used to join thicker sections of carbon, or low alloy steel plate. The method provides high welding speeds, but all welding is done in a horizontal position unless special fl

57、ux-holder are used.p最常使用埋弧焊连接的是碳钢或低合金钢板的厚板。该方法最常使用埋弧焊连接的是碳钢或低合金钢板的厚板。该方法焊接速度快，但只能在水平位置上施焊，除非使用特殊的焊焊接速度快，但只能在水平位置上施焊，除非使用特殊的焊剂盛放装置。剂盛放装置。- - 4242 - -CHAPTER 12 WELDING TECHOLOGYpPlasma arc welding (PAW) is similar to gas tungsten arc welding, in that an electric arc is discharge between the workpiece and a nonconsumable tungsten electrode. The arc for plasma arc welding, however, is conducted to the workpiece by a controlled stream of plasma (electrically charged gas capable of conducting electricit