The resistance welding is resistance welders member pressed in between the two electrodes, and pass a current, a current flows through the workpiece contact surfaces and adjacent areas generated heat will be heated to a molten or plastic state, so as to form the metal binding methods.

Spot welding, the workpiece is only in a limited contact surface, i.e. on the so-called "point" are welded together, and to form a flat spherical nugget. Spot welding can be divided into a single spot welding and spot welding. When the multi-spot, using two or more pairs of electrodes, a plurality of the nugget is formed in the same step.

The seam welding similar spot welding. Seam welding, the workpiece to pass between the two rotating disc-shaped electrode (roller disk) after forming the continuous weld lap around the articles pads.

The projection welding is a variant of the spot welding. A workpiece prefabricated bumps. Projection welding, one can at the joints to form one or more of the nugget.

Butt welding, the end face of contact of the two workpieces are welded together along the entire contact surface, after the resistor heating and pressing.

Resistance welding have the following advantages:

1) nugget formation, has always been surrounded by a plastic ring, molten metal and air separation, simple metallurgical process.

2) the heating time is short, heat is concentrated, so a small heat-affected zone, the deformation and stress is also small, and usually do not have to arrange correction after welding and heat treatment processes.

3) does not require wires, rods and filler metal, as well as oxygen, acetylene, argon and other Welding Material welding and low cost.

4) the operation is simple, easy to implement mechanization and automation, improve labor conditions.

5) high productivity, with no noise and harmful gases in the mass production and other manufacturing processes allocated to the assembly line. But flash butt welding sparks splash isolated.

Resistance welding drawbacks:

1) there is a lack of reliable non-destructive testing methods to check welding quality can only rely on the destructive testing process specimens and artifacts as well as rely on a variety of monitoring techniques to ensure.

2) points, seam welding a lap joint, not only increases the weight of the member, and the periphery of the nugget is formed between the two plates, the angle between lower, resulting in joint tensile strength and fatigue strength.

3) equipment power, a higher degree of mechanization and automation, the high cost of equipment, maintenance more difficult, and used high-power single-phase AC welder is not conducive to the normal operation of the power grid. Electrode wear as aerospace, electronics, automotive, household appliances and other industrial development, resistance welding together the more attention by the society, at the same time, the resistance welding quality put forward higher requirements. The good news is that China's development of microelectronics technology and high-power thyristor rectifier development, resistance welding technology to improve conditions. At present, China has produced excellent secondary rectification Welding Wire China. Made by integrated components and microcomputer control box has been used for the new welder supporting the transformation of the old welder. Constant current, dynamic resistance, thermal expansion, advanced closed-loop control technology has begun to promote the application in production. All this will be something to help improve the welding quality, and expand its application areas.