Percussion welding is a type of resistance welding process. Coalescence in percussion welding is produced by high-temperature heat obtained from an arc produced by a rapid discharge of electrical energy. And the pressure is (rapidly) applied during or immediately after an electrical discharge.
Percussion welding is accomplished in the following steps:
First of all, the workpiece is freed from grease, dirt, paint, etc., then the workpiece is clamped in a machine or fixer, then the two ends of the workpiece to be joined are brought together using light force. thereafter, the arc is struck between the faces of the workpiece, using several methods such as
- The workpiece is brought into light contact to establish the flow of current. Then the workpiece is pulled back to draw the arc,
- By cutting one of the pieces to form a nib of smaller cross-sectional area, as current flows through the nib, the nib explodes thereby establishing an ionized path for the welding current to flow.
See More: Welding Arc establishment
- In another method, when sufficient DC voltage is applied, the air gap between the workpieces is neutralized and the current begins to flow
- Another method is also used to generate an arc, in which an auxiliary high-frequency, high-voltage AC is superimposed on a low-voltage current in the gap between the workpieces. Here high-frequency AC ionizes the air in the gap and maintains the low-voltage DC arc.
The arc is produced using one of the above methods and is heated to join the faces of two workpieces.
Power supplies for percussion welding are as follows:
|Low voltage (D.C)||10-150 Volts||Capacitive storage|
|High voltage (D.C)||1000-6000 Volts||Capacitive storage|
|Electromagnetic or inductive storage|
|Low voltage (A.C)||10-35 Volts||Uses a transformer to furnish|
The following types of metals can be welded by percussion welding
- Copper to Molybdenum
- Stainless steels
- Low carbon steels
- Aluminum alloys
- Medium Carbon steels
- Nickel alloys
- Copper alloys