Resistance welding

From GAWDAwiki

Resistance welding refers to a group of welding processes in which coalescence results from application of pressure and from heat produced by resistance between a work piece and an electric current.[1]

There are at least seven forms of resistance welding.

Resistance Spot Welding

Resistance spot welding uses heat from an electric current between work pieces held together under pressure and electrodes to produce coalescence at the faying surface in a single spot. The size and shape of individually formed welds are determined by the electrodes used.

Learn more about resistance spot welding.

Projection Welding

Projection welding is similar to spot welding, but the size and shape of welds are not determined by the electrodes being used. Rather, they are determined by the base metals themselves. Welds and heating are localized at pre-determined points based on projections, embossments or intersections.

Learn more about projection welding.

Resistance Seam Welding

Resistance seam welding uses electrodes in the form of wheels to join two pieces. The process results in a series of overlapping resistance spot welds.

Learn more about resistance seam welding.

Flash Welding

Flash welding produces coalescence over the entire area of abutting surfaces via heat and pressure. The process is named for the “flash” created when metal is expelled. An arc is formed between the pieces after this expulsion and it is maintained until they reach their melting points. Pressure is then applied, the arc is extinguished and upsetting occurs.

Learn more about flash welding.

Upset Welding

Upset welding differs from flash welding in that pressure is applied before heating commences and is maintained for the duration of the heating period. Once a sufficient forging temperature is reached in the joint, upsetting occurs and the current is stopped.

Learn more about upset welding.

Percussive Welding

Percussive, or percussion, welding produces coalescence of abutting members using a high-temperature arc formed after a rapid discharge of electrical energy. Pressure may be applied during or immediately following this discharge. Percussive welding may be used only on parts of the same geometry and cross section.

Learn more about percussive welding.

High-Frequency Resistance Welding

High-frequency resistance welding uses a current in the 10,000 to 500,000 hertz range in order to join metals via coalescence. The high-frequency current is applied to the surfaces of the pieces to be joined before they make contact with each other.

Learn more about high-frequency resistance welding.^[1]