This also allows the use of flat electrodes, which are most easily dressed to an original condition. Then moves again and is welded. Butt welding Typically used to join the ends of two pieces of wire. The ends of the wire are clamped and brought together under pressure, then current is applied to form the weld. Top Fundamentals of Resistance Welding A spot weld is made by applying pressure to two or more pieces of overlapping metal, then passing an electrical current through a localized contact area, for a very specific time period, to heat the area till a weld nugget forms.
Force is continued to be applied after the weld time until the weld has solidified and forged.
To minimize heat dissipation the weld is formed very quickly. This requires very large electrical transformers. PCT are the factors used to construct a weld schedule. To use the schedule you look up the size of the thinnest piece of metal being welded. Looking across, you will see values for the correct amount of force, the proper weld time value, and the amount of amperage necessary to weld.