Resistance welding has the following advantages：
1. When the nugget is formed, it is always surrounded by a plastic ring, the molten metal is isolated from the air, and the metallurgical process is simple.
2. The heating time is short and the heat is concentrated, so the heat-affected zone is small, and the deformation and stress are also small. Usually, it is not necessary to arrange the correction and heat treatment process after welding.
3. It does not need filler metals such as electrodes and wires, and welding materials such as oxygen, acetylene, and argon, and the welding cost is low.
4. Simple operation, easy to realize mechanization and automation, and improve working conditions.
5. High productivity, and no noise and harmful gases. In mass production, it can be compiled into the assembly line together with other manufacturing processes, but flash butt welding needs to be isolated due to sparks.
Resistance welding has the following disadvantages：
1. Lack of reliable non-destructive testing methods, welding quality can only be checked by destructive tests of process samples and weldments, as well as by various monitoring techniques to ensure.
2. The lap joint of point and seam welding not only increases the weight of the component, but also forms an angle around the nugget between the two plates, resulting in low tensile strength and fatigue strength of the joint.
3. The equipment has high power, mechanization and automation, which increases the cost of equipment. Maintenance is more difficult, and the commonly used high-power single-phase AC welding machine is not conducive to the normal operation of the power grid, and needs to be distributed separately.
The main resistance welding methods are spot welding, seam welding, projection welding and butt welding.