FUNDAMENTALS OF RESISTANCE WELDING - 1.

Two conditions must be met to produce a good weld: the oxide layer covering the metal surfaces must be eliminated, and the irregular surface of the metals must be brought into intimate contact all along the bond. All present day welding processes are just different ways of achieving these two goals by using various combinations of heat, pressure and time. At one extreme is the oxyacetylene torch method, representing heat and time only. At the other end of the scale is the compressive or cold weld which is accomplished with pressure and time. Because it uses heat, pressure and time, resistance welding holds a place between these two extremes. The pressure is applied by electrodes which also carry a current that generates heat at the metal interface. This article presents basic information about the technique, including power source, types of resistance welds, and forms of resistance welding.