Two-dimensional model describing electric conduction and heat transfer within electrodes and plates during resistance seam welding is developed. The model is numerically solved using a finite element method. The effect of electric current path length on welding phenomena is numerically 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 current range.
The effect of tin coating weight on the heat affected zone and 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 calculation and the experiment shows that the experimental results can be explained by the change in the current path length. The model also predicts the experimental relation between weldability and dynamic electric resistance measured between the electrodes.
