Electric Welding Control
Welding is important and necessary process required in fabrication. There are basically three types of welding systems :
1. Forge welding
2. Fusion welding
3. Resistance welding
1. Forge welding :
- Here the jobs that are to be welded are heated upto their plasticity stage and then the jobs are superimposed to form a joint by applying pressure externally by either power hammering or pressing the jobs together.
- This is one of the oldest type of welding .
2. Fusion welding :
- In fusion welding the pieces to be welded are heated at their joints till they enter into their molten state and then allowed to cool and solidify.
- In this there is a need for filter material. This welding takes place at very high temperature.
- The welding can take place by arc and the electrode melts in this process. Gas welding (CO2 gas) is also used in the fusion welding.
- The heat for the welding is obtained by passing an electric current (by arcing it) through a metal job.
3. Resistance welding :
- Resistance welding is a process in which two or more metal pieces are welded by passing a short duration high value ac or de current through the area of contact between the metal pieces.
- The duration for which the current is passed varies from a few milli seconds to several seconds depending on the type of job.
- The amplitude of current will also vary depending on which metal is to be welded.