Resistance welding is a high-speed method of joining metals by applying pressure and electrical heat under accurate controls, making a weld in a fraction of a second.
In a resistance weld, a large amount of welding current is passed through a concentrated area – also known as the weld zone – for a specific time while being held under a localized forging pressure. Heat energy is generated when an electrical current passes through an electrical resistance.
Since resistance is the highest at the faying surfaces (part to part interface), a greater volume of heat is generated at that interface allowing the metal to become molten. A forging pressure is applied at the molten area and the work pieces will alloy together to form a weld nugget.
Closeup of a spot welding nugget being formed.
The formula for making a good resistance weld includes the proper amount of force, current, time and temperature.
Spot welding is the most common form of resistance welding. Opposing electrodes or tips conduct and concentrate welding current and apply forging force to form each weld.
Projection welding is similar to spot welding except that embossed or solid projections in the part being welded concentrate the heat and form the welds. Multiple projections can be welded with one stroke of the machine.
Seam welding is accomplished with a machine equipped with copper wheels (round electrodes) that rotate and produce a continuous or intermittent weld joint.
Butt welding is typically used to join ends of wire together.
Flash welding is used to butt weld large diameter parts together.
When properly applied, resistance welding has many advantages over other metal joining methods including a low cost and little operator training required.
Once proper parameters are developed, a resistance weld is a fast and efficient way of joining two metals together without the use of gases or filler metals. The welding process can be continued automatically as fast as the material can be fed to the machine.
T. J. Snow has a deep understanding of the resistance welding process. We design, manufacturer and deliver solutions that improve quality, durability and productivity. Our engineered solutions deliver improved performance and consistent results.
To gain a better understanding of the resistance welding process, T. J. Snow offers a variety of training options including seminars hosted at your plant and classes offered throughout the United States.