Resistance welding is a method of forming a metal bond by heating the workpiece to a molten or plastic state through the resistance heating effect generated by the current flowing through the contact surface and adjacent areas of the workpiece. There are four main methods of resistance welding, namely spot welding, seam welding, projection welding, and butt welding.

Characteristics of Resistance Welding

1: Resistance welding is the process of using the resistance heat generated inside the welded component to conduct from the high temperature zone to the low temperature zone, heating and melting the metal to achieve welding. It belongs to internal distributed energy.

2: The weld seam of resistance welding solidifies or crystallizes under pressure, belonging to the category of pressure welding and possessing forging characteristics.

3: Due to the concentration of welding heat and short heating time, the heat affected zone is small, and welding deformation and stress are also small. So, usually there is no need for correction or heat treatment after welding.

4: Usually, welding materials such as welding wire, flux, and shielding gas are not required, resulting in low welding costs.

5: The fusion core of resistance welding is always surrounded by solid metal, and the melted metal is isolated from air, making the welding process relatively simple.

6: Easy to operate, easy to implement mechanization and automation, with good working conditions.

7: High productivity, can be arranged together with other processes on the assembly and welding production line. However, flash welding still needs to be isolated due to sparks splashing.

8: Due to the high power, mechanization, and automation of resistance welding equipment, it requires a large initial investment and is difficult to maintain. Additionally, commonly used high-power single AC welding machines are not conducive to the normal operation of the power grid.

9: The lap joint of point and seam welding not only increases the quality of the component, but also reduces the tensile strength and fatigue strength of the joint.

10: At present, there is a lack of reliable non-destructive testing methods for the quality of resistance welding, which can only be checked by process samples, destructive tests, and various monitoring technologies.