EFFECT OF ELECTRIC-CURRENT PATH AREA ON R ESISTANCE SEAM WELDABILITY

Two-dimensional model describing electric conduction and heat transfer within electrodes and plates during resistance seam welding is develo ped. The model is numerically solved using a finite element method. Th e effect of electric current path length on welding phenomena is numer ically investigated. The calculation demonstrates that decrease of the current path length on the electrode/plate and plate/plate interfaces shortens the heat affected zone and that it decreases weldable curren t range. The effect of tin coating weight on the heat affected zone an d weldable current range is experimentally investigated. As a result, the weldable current range and the heat affected-zone length decrease with decreasing the tin coating weight. A comparison between the calcu lation and the experiment shows that the experimental results can be e xplained by the change in the current path length. The model also pred icts the experimental relation between weldability and dynamic electri c resistance measured between the electrodes.