A study on the joining strength of laser spot welding for automotive applications

Abstract Laser beam welding offers a unique combination of high speed, precision and low heat distortion, compared with the conventional welding process. This combination of advantages is especially attractive for the automotive industry. Until now automobile fabrication has widely used resistance spot welding (RSW), however, because of geometrical and structural problems, RSW requires many welding machines for which reason by substituting RSW with laser spot welding (LSW), there are savings in equipment cost. Many factors need to be considered when replacing one joining method with another. In the present case, the strength differences between laser-spot and resistance-spot welds must be ascertained before LSW can be implemented in selected applications. Therefore, the low-cycle fatigue strength and residual stress of laser spot welded specimens were measured and compared with those of RSW results in order to adapt LSW in the automobile industry. Also for strength estimation, the residual stress of the laser spot welded zone was calculated. All of the calculations were performed with the ABAQUS code on a workstation.