Electric Welding Control

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.