In percussion welding, the welding heat is obtained by an arc produced by a rapid discharge of stored electrical energy in capacitor. The parts to be joined are placed in position similar to flash welding. The intense heat of arc melts the parts. The heated parts are then pressed together to complete the weld. This process is very fast on account of rapid discharge of power to the arc. The arc durations are only 1–10 ms, after which it is extinguished by the percussion blow of the two parts coming together. The use of this process is limited to very thin wires of diameters from 0.05 to 0.38 mm. It can also be used for joining wires of dissimilar metals such as copper to nichrome and copper to stainless steel.
Advantages
- There is no thermal distortion due to small heat affected zone.
- The metal of different thermal conductivity can be welded easily as heat is concentrated at the two surfaces only.
- No upsetting occurs at the joint.
- Heat treated part may be welded without being subjected to annealing.
Disadvantages
- Only small areas can be welded.
- Part should have regular section.
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