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

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 indus try. Until now automobile fabrication has widely used resistance spot weldi ng (RSW), however, because of geometrical and structural problems, RSW requ ires 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 a nother. In the present case, the strength differences between laser-spot an d resistance-spot welds must be ascertained before LSW can be implemented i n selected applications. Therefore, the low-cycle fatigue strength and resi dual 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 cod e on a workstation. (C) 1999 Elsevier Science S.A. All rights reserved.