Resistance welding is divided into three types: spot welding, seam welding and butt welding.

(1) Spot welding: the weldment is pressed between the two columnar electrodes, and is heated by electricity to melt the weldment at the contact to form a nugget, then power off, and solidify and crystallize under pressure to form a dense joint. .
Spot welding is suitable for welding thin plates (laps) and steel bars up to 4 mm, and is widely used in the production of automobiles, airplanes, electronics, instruments and daily necessities.

(2) Seam welding: Seam welding is similar to spot welding except that a rotating disk electrode is used instead of the column electrode. The stacked workpieces are energized between the discs and fed as the disc rotates to form a continuous weld.
Seam welding is suitable for welding thin plates with a thickness of less than 3 mm. It is mainly used for the production of sealed containers and pipes.

(3) Butt welding: According to the welding process, butt welding can be divided into resistance butt welding and flash butt welding.