1)Resistance Spot Welding: 
It is a process to join two or more metal sheets by applying pressure and passing an electric current through them. The resulting resistance heating melts the metal at a concentrated spot, creating a fused bond upon cooling. This efficient, cost-effective, and automatable process is widely used in the automotive industry for joining thin sheets.

2)Projection Welding: 
It is a type of resistance welding that uses pre-designed projections on the workpiece to concentrate electrical current and pressure at specific, small points. This process creates strong welds by efficiently generating heat where needed. This allows for precise control, potential for multiple welds at once, and improved weld quality.

3)Seam Welding: A welding method that uses two rolling electrodes (wheels), one above the other, to apply pressure to the workpieces and weld them together through the passage of an electric current. It is primarily used for continuous welding of thin metal sheets, such as metal tin cans, water tank, fire extinguisher, and steel fuel tank...etc. 

4)Butt Welding: A resistance welding process used to join thick metal plates/files or bars end-to-end. It works by applying opposing forces directly with electrodes that clamp the workpieces. After the workpieces are heated, a forging operation is applied. Often, no melting occurs, resulting in a solid-state weld. This welding method is widely used in the manufacturing of items like wires joints, strips and rods, construction rebars, wheel rims, steel bar, chain links, tubes, pipelines, profiles, connecting rods...etc.