1. When the nugget is formed, it is always surrounded by a plastic ring, and the molten metal is isolated from the air, so the metallurgical process is very simple. 2. Short heating time, concentrated heat, small heat affected zone, and small deformation and stress. There is usually no need to arrange calibration and heat treatment procedures after welding.

3, filler metals such as welding wire and covered electrode and welding materials such as oxygen, acetylene and hydrogen are not needed, and the welding cost is low.

4. Simple operation, easy mechanization and automation, and improved working conditions.

5, high productivity, no noise and harmful gas, and can be woven into an assembly line together with other manufacturing processes in mass production. However, flash butt welding needs isolation because sparks fly.

disadvantaged

There is no reliable nondestructive testing method before 1. The welding quality can only be checked by nondestructive testing of process samples and workpieces, and ensured by various monitoring technologies.

2. The lap joint welded by spot welding and seam welding not only increases the weight of the component, but also forms an included angle around the weld core of the two plates, which leads to the decrease of the tensile strength and fatigue strength of the joint.

3. The high power, mechanization and automation of the equipment make the equipment more expensive and difficult to maintain, and the commonly used high-power single-phase AC welding machine is not conducive to the balanced operation of the power grid.