Projection welding process: Definition, and working principle

Projection welding process

It is a set of resistance welding processes wherein Unionization is produced by the heat received from resistance to electric current flow through the work parts held together under pressure by electrodes.

The projection welding process is very similar to the spot welding process. Multiple welds are made in each operation, whether it is driven by electric force or by mechanical pressure.

Welding Equipment

A projection welding machine is a press-type machine, like a spot-welding machine, in which the welding head is actuated by air, spring, or hydraulic system.

Low carbon steels, Coated metals i.e. Galvanized steel, terne plate, tin plate, etc. are satisfactorily welded by the projection welding process.

Advantages and limitations of the projection welding process

This process is very beneficial in many cases,such as :-

  • Thicker parts of metals, which are difficult to welding by spot welding, can be welded by projection welding.
  • Multiple welds can be welded by this process at once.
  • By this method, multiple welds can be made simultaneously.
  • Electrodes in projection welding run longer than spot welding, due to less wear and maintenance resulting from fusion and overheating.
  • Less power and pressure consumption needed.

Although projection welding is a profitable welding method, it has some limitations such as:-

Metal that is not strong enough, can not weld satisfactorily by projection weldings such as some brasses or copper is important to arrange all projections at the same height to achieve proper welding.

Applications projection welding process

Projection welding is used extensively in the automobile sector.

Fasteners, nuts are used to weld with large components by projection welding.


Projection welding is very suitable for mass production such as welding of refrigerator condenser, cross-welding (rack, gritting, grill), etc.