《洛阳理工专业英语课件.》由会员分享，可在线阅读，更多相关《洛阳理工专业英语课件.（23页珍藏版）》请在金锄头文库上搜索。
1、Unit 3 Welding 焊接 ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3 Welding 1 3 Welding Emphasis： Shielded Metal Arc Welding 自动保护金属极电弧焊 Gas Metal Arc Welding 气体保护金属极电弧焊 Plasma Welding 等离子 焊 Submerged Arc Welding 埋弧焊 (merge 合并，熔合) Resistance Projection Welding 电阻凸焊 Difficulty: Flux 助焊剂-cored Wire Wel
2、ding 药芯焊丝焊 ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II Project vt. 计划 n. 项目 Projection n. 计划 n. 突出 电阻凸焊：在工件上有预制凸点 ，可以一次在接头处形成一个或 多个熔核 2 3.1 Introduction to Welding Processes Welding is essential 实质上 for the manufacture of a range of engineering components, which may vary from (vary from a to b 在
3、a到b范围内变化 ) very large structures such as ships and bridges to miniature 微型的 components for microelectronic applications. Several alternative 两者中选一的 definitions are used to describe a weld, for example: ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1 Introduction to Welding Processes3.1.1 Definit
4、ion and Classification of Welding Processes 给予，提供；致使 3 Based on these definitions welding processes may be classified into those which rely on the application of pressure and those which used elevated temperatures to achieve the bond. The most important processes are shown in Figure 3.1 ENGLISH IN M
5、ATERIALS SCIENCE AND ENGINEERING II 3.1.1 Definition and Classification of Welding Processes or alternatively: 结合 Either or 或者或者，二选一 4 ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.1 Definition and Classification of Welding Processes 驱动 对接 手工电弧焊 药芯焊 5 Key words: render 给予，提供；致使 filler metal 填充
6、金属 parent metal 母材 coalescence 结合 ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.1 Definition and Classification of Welding Processes 6 The most widely used welding processes rely on fusion of the components at the joint 接头，接缝 line 结 合线. In fusion welding, a heat source melts the metal to form
7、a bridge between the components. A wide used heat source is electric arc, as shown in Figure 3.2. ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.1 Definition and Classification of Welding Processes Figure 3.2 Welding arc 7 The molten metal must be protected from 保护免受 the atmosphere absorption o
8、f oxygen and nitrogen leads to a poor quality weld. Air in the weld area can be replaced be a gas which does not contaminate the metal, or the weld can be covered with a flux 助焊剂. A large number of fusion welding processes and techniques are available. No process is universally 通用 的，万能的 (univers 宇宙，
9、万物，总体；General Motor Company, 美国通用公司) best. ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.1 Definition and Classification of Welding Processes 8 Each has its own special attributes 特性，属性 and must be matched to the application. Choosing the most suitable process requires consideration of a numbe
10、r of factors, including type of metal, type of joint 接头，接 缝, material thickness, production constraints 约束，限 制, equipment availability 可用性, labour 劳力，劳工 availability, labour costs, costs of consumables 消耗品, health, safety and the environment consideration. ENGLISH IN MATERIALS SCIENCE AND ENGINEERIN
11、G II 3.1.1 Definition and Classification of Welding Processes 9 Shielded metal arc welding 自动保护金属极电弧焊 process, shown in Figure 3.3, is also known as manual a. 手工的；n. 手册 metal arc welding (MMA) in Europe. ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.2.1 Shielded Metal Arc Welding (SMAW) Figure
12、 3.3 shielded metal arc welding 10 ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.2.1 Shielded Metal Arc Welding (SMAW) 11 It has for many years been one of the most common techniques 技术 applied to the fabrication 制造；捏造 of steels. The process uses an arc as the heat source and shielding 防护物 is
13、provided by gases generated by the decomposition of the electrode coating material and by the slag produced by the melting of mineral constituents 成分 of the coating. ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.2.1 Shielded Metal Arc Welding (SMAW) 12 In addition to 此外 heating and melting the
14、 parent material (and) the arc also melts the core of the electrode and thereby provides filler material for the joint. The electrode coating 药皮 may also be used as a source of alloying elements and additional filler material. The flux and electrode chemistry may be formulated 配制 to deposit wear- an
15、d corrosion-resistant layers for surface protection. ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.2.1 Shielded Metal Arc Welding (SMAW) 13 Significant features of the process are: (1) equipment requirements are simple; (2) a large range of consumables 耗材 are available; (3) the process is extr
16、emely portable 便携的; (4) the operating efficiency is low; (5) it is labour intensive 密集的；精度的. For these reasons the process has been traditionally used in structural steel fabrication, shipbuilding and heavy engineering as well as for small batch 一批 production and maintenance 维 修，保养。 ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.2.1 Shielded Metal Arc Welding (SMAW) 14 Key words: shielded metal arc welding (SMAW) 手工电弧焊 electrode 焊条，电极 slag 熔
