Temperature Distributions at Various Stages of Spot Welding

Abstract

Foundamental formulas were derived by the following assumptions.
1. The material and electrode are thermally one body and infinite.
2. The current flows uniformly over the path.
3. The specific heat, density and diffusibility of heat of materials and the mechanical equivalent of heat are constant.
4. The temperature coefficient of the specific resistance and current density are functions of time.
5. The contact resistance distributes uniformly on the surface and keeps constant until it disappears.
6. A thermally neutral.point exists on the center line of the current path because of the cooling effect of the electrode.
Then, from these foundamental formulas, temperature distributions at various stages of spot welding are derived.
At last, the effect of the thermal isolation by the plate surface and the plate end is calculated.