This type of welding is a pressure process, as is forge welding. It consists of heating to their plastic temperature the surfaces of parts to be joined, then applying pressure mechanically to achieve complete union of the parts. The heating is accomplished by passage of a heavy, localized electric: current. Alternating current of common commercial voltage is employed for this purpose.
In all types of resistance welding, selection of proper electrodes is important to the success of the process. Electrodes must possess a high degree of thermal and electrical conductivity, and they also must possess strength and hardness.
Spot Welding— this process consists of holding two more metals between suitable electrodes which pass a heavy current through the materials to be welded.
The electrodes then arc forced together by pressure of sufficient force to join the surfaces of the base metals in a spot.
A spot-welding machine is the simplest form of resistance-welding device; therefore it is widely adapted throughout the metal-working industry.
Butt-Welding — By this process the parts to be welded are gripped mechanically and pressed together while heat is generated by passage of a heavy current through the area of the joint.
Butt welding is used extensively for resistance welding work. Pipes, tubing, bars, rods, light- and medium-weight structural shapes, etc., may be butt welded.
Word List:
forge welding – кузнечне зварювання
complete union of the parts – прочне з’єднання частин
accomplish – здійснювати, виконувати
resistance welding – контактне зварювання
degree of thermal and electrical conductivity - ступінь термоелектричної провідності