Resistance Welding Method

There are many types of electric resistance welding(erw), and there are three types of welding, seam welding, butt welding and projection welding.

First, spot welding
Spot welding is a method of electric resistance welding in which a weldment is assembled into a lap joint and pressed between two columnar electrodes to melt the base metal by electric resistance to form a solder joint. Spot welding is mainly used for thin plate welding.

Spot welding process:
1. Preloading to ensure good contact with the workpiece.
2. Power on, so that the weld is formed into a nugget and a plastic ring.
3. Power-off forging, so that the nugget cools and crystallizes under the pressure, and forms a welded joint with dense structure, no shrinkage hole and crack.

Second, seam welding
Seam welding is mainly used for welding welds that are relatively regular and require sealing. The thickness of the joint is generally less than 3 mm.

Third, butt welding
Butt welding is a resistance welding method in which a 35Crmo alloy tube is welded along the entire contact surface.

Fourth, projection welding
Projection welding is a variant of spot welding; there are prefabricated bumps on a workpiece, and one or more nuggets can be formed at the joint at a time.