NON-MECHANICAL JOINTS 2 PROFESSIONAL ENGLISH IN USE FOR ENGINEERING

 

PROFESSIONAL ENGLISH IN USE FOR ENGINEERING UNIT 29. NON-MECHANICAL JOINTS 2

 

A Specialized welding techniques The web page below, from a technical guide to welding techniques, explains some more specialized welding methods. Resistance welding involves passing an electric current through metal components that are touching. This heats the metal and welds it. The technique can be used for spot welding – welding a number of small points between the surfaces of the components. It can also be used for seam welding, to make long, narrow welds. B Brazing and soldering In brazing, brass – an alloy of copper (Cu) and zinc (Zn) – is melted using an oxyfuel torch, and added as filler to form the joint. Unlike welding, the base metal of the components is not melted, so the components are not fused. Brazed joints are therefore not as strong as welded joints. C Adhesives Adhesive – called glue in everybody language – can be used to bond (permanently join) components together. Its purpose is to adhere to the surfaces being joined, to create a bond between them. Most adhesives are liquids, which can be applied to (put on) the surfaces that need to be glued together. EXERCISES 29.1 Make word combinations with welding using words from A opposite. Then match the combinations with the descriptions (1-4) below. 1. components are joined by several small welded points 2. the weld is in the form of a very thin line 29.2 Tick one or more of the boxes to show which technique(s) each sentence applies to, or leave all three boxes empty if the sentence applies to none. Look at B opposite to help you. 29.3 Choose the correct words from the brackets to complete the sentences about adhesives. Look at C opposite to help you. 1. Surfaces can be glued together by applying different types of (adhesive/ adhesion). 2. When adhesive-covered surfaces touch, they (adhere to/ apply to) each other. 3. If an adhesive reacts with the material which the components are made from, it forms a (chemical bond/ mechanical bond) with the material.

ANSWER KEY