洛阳理工专业英语课件

1、Unit 3 Welding 焊接 ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3 Welding 3 Welding 23 Welding 3 Welding EmphasisEmphasis：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:Dif

2、ficulty: Flux 助焊剂-cored Wire Welding 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33.1 Introduction to Welding Processes3.1 Introduction to Welding Processes Welding is essential 实质上 for the manufacture of a rang

3、e of engineering components, which may vary from (vary from a to b 在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 A

4、ND ENGINEERING II 3.1 Introduction to Welding Processes3.1 Introduction to Welding Processes3.1.1 Definition and Classification of Welding Processes给予，提供；致使4 Based on these definitions welding processes may be classified into those which rely on the application of pressure and those which used eleva

5、ted temperatures to achieve the bond. The most important processes are shown in Figure 3.1ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.1 Definition and Classification of Welding Processesor alternatively:结合Either or 或者或者，二选一5ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.1 Definition and

6、 Classification of Welding Processes驱动对接手工电弧焊药芯焊6 Key words: render 给予，提供；致使 filler metal 填充金属 parent metal 母材 coalescence 结合 ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.1 Definition and Classification of Welding Processes7 The most widely used welding processes rely on fusion of the compone

7、nts at the joint 接头，接缝 line 结合线. In fusion welding, a heat source melts the metal to form 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 ProcessesFigure 3

8、.2 Welding arc8 The molten metal must be protected from 保护免受 the atmosphere absorption of 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

9、 processes and techniques are available. No process is universally 通用的，万能的 (univers 宇宙，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 Processes9Each has its own special attributes 特性，属性 and must be matched to t

10、he application. Choosing the most suitable process requires consideration of a number 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, safe

11、ty and the environment consideration.ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.1 Definition and Classification of Welding Processes10 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 MATERI

12、ALS SCIENCE AND ENGINEERING II 3.1.2.1 Shielded Metal Arc Welding3.1.2.1 Shielded Metal Arc Welding (SMAW) (SMAW) Figure 3.3 shielded metal arc welding11ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.2.1 Shielded Metal Arc Welding3.1.2.1 Shielded Metal Arc Welding (SMAW) (SMAW) 12 It has for ma

13、ny 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 provided by gases generated by the decomposition of the electrode coating material and by the slag produced by the melting of mineral constit

14、uents 成分 of the coating.ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.2.1 Shielded Metal Arc Welding3.1.2.1 Shielded Metal Arc Welding (SMAW) (SMAW)13 In addition to 此外 heating and melting the parent material (and) the arc also melts the core of the electrode and thereby provides filler materi

15、al 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- and corrosion-resistant layers for surface protection.ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.

16、1.2.1 Shielded Metal Arc Welding3.1.2.1 Shielded Metal Arc Welding (SMAW) (SMAW)14 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 extremely portable 便携的; (4) the operating efficiency is low; (5) it

17、 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 Weldin

18、g3.1.2.1 Shielded Metal Arc Welding (SMAW) (SMAW)15 Key words: shielded metal arc welding (SMAW) 手工电弧焊 electrode 焊条，电极 slag 熔渣 joint 接头，接缝ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.2.1 Shielded Metal Arc Welding3.1.2.1 Shielded Metal Arc Welding (SMAW) (SMAW)焊接接缝的形式16 Gas metal arc welding,

19、 shown in Figure 3.4 and Figure 3.5, is also known as metal inert gas (MIG) or metal active gas (MAG) welding in Europe. ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.2.2 Gas Metal Arc Welding 3.1.2.2 Gas Metal Arc Welding (GMAW) (GMAW)Figure 3.4 Gas Metal Arc Welding17ENGLISH IN MATERIALS SCI

20、ENCE AND ENGINEERING II 3.1.2.2 Gas Metal Arc Welding 3.1.2.2 Gas Metal Arc Welding (GMAW) (GMAW)CO2气体保护焊CO2气体保护焊机18ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.2.2 Gas Metal Arc Welding 3.1.2.2 Gas Metal Arc Welding (GMAW) (GMAW)Figure 3.5 GMAW system焊炬夹钳 导线 软管 调节阀 19Gas metal arc welding us

21、es the heat generated by an electric arc to fuse 熔化；保险丝 the joint area. The arc is formed between the tip 尖端 of a consumable, continuously fed filler wire and the workpiece and the entire arc area is shielded by an inert gas. The principle of operation is illustrated in Figure 3.6.ENGLISH IN MATERIA

22、LS SCIENCE AND ENGINEERING II 3.1.2.2 Gas Metal Arc Welding 3.1.2.2 Gas Metal Arc Welding (GMAW) (GMAW)喷嘴小滴Principle 原理Principal 首要的；校长20 Some of the more important features of the process are summarized below: (1) low heat input ( compared with SMAW and SAW); (2) continuous operation; (3) high depo

23、sition rate; (4) no heavy slag reduced post-weld cleaning; (5) low hydrogen reduces risk of cold cracking. Depending on the operating mode of the process it may be used at low currents for thin sheet or positional 位置的welding 全位置焊.ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II 3.1.2.2 Gas Metal Arc

24、Welding 3.1.2.2 Gas Metal Arc Welding (GMAW) (GMAW)21 The process is used for joining plain carbon steel sheet from 0.5 to 2 mm thick in the following applications: automobile bodies, exhaust 排气 systems, storage tanks 储藏罐, tubular 管状的 steel furniture, heating and ventilating 通风的 ducts 风管. The process is applied to positional welding of thick plain carbon and low alloy steels in the following areas: oil pipelines, marine structures and earth-moving 土方移动 equipment. ENGLISH IN MATERIALS SCIENCE AND ENGINEERING II