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47
Reading 2
11 You will read the text Alternative Types of Welding. Before you read
suggest your answers to the following questions.
1. What is the difference between the principle (“traditional”) and alternative
types of welding?
2. Why are traditional welding processes not sufficient?
12 Match welding types (1-6) with their description (A-F). Then read the
text and check your answers.
1. Cold welding A. Light energy is used to weld parts together.
2. Friction welding B. The weld is formed at the expense of the applied
pressure at a high temperature for a long period of
time.
3. Laser welding C. Vibration is used to generate heat necessary to
produce a weld. e
4. Diffusion bonding D. The heat to accomplish the joint is generated by
rotation.
5. Ultrasonic welding E. The most important factor to accomplish the weld
is pressure. No heat is applied.
6. Explosive welding F. Rapid plastic deformation of the welded materials
is caused by detonation.
Alternative Types of Welding
Cold welding
Cold welding, the joining of materials without the use of heat, can be
accomplished simply by pressing them together. Surfaces have to be well
prepared, and pressure sufficient to produce 35 to 90 percent deformation at
the joint is necessary, depending on the material. Lapped joints in sheets and
cold-butt welding of wires constitute the major applications of this
technique. Pressure can be applied by punch presses, rolling stands, or
pneumatic tooling. Pressures of 1,400,000 to 2,800,000 kilopascals (200,000
to 400,000 pounds per square inch) are needed to produce a joint in
aluminum; almost all other metals need higher pressures.
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