Comparative study on CO2 laser overlap welding and resistance spot welding for automotive body in white

Our previous study included a comparative analysis of the characteristics of CO2 laser overlap welding and resistance spot welding in terms of the weld fundamentals, tensile-shear performance, microstructure, hardness, and corrosion resistance of welding joints. In this study, the processing properties of the two types of welding methods were further investigated. First, experiments were conducted on dissimilar auto body sheets using resistance spot welding and laser welding with different weld lengths. Next, the layout of the laser welding joints was analyzed. Finally, experiments were performed on an auto door sub-assembly using resistance spot welding and laser welding respectively. Experimental results showed that both the sheet thickness and weld pool width were correlated with the laser weld length (LWL). When the LWL was increased to 20 mm, the tensile-shear performance of the specimen was better than that of one resistance-spot welding point under various conditions. When performing weld joint layout using the "short-length and multi-segment'' scheme, it was possible to produce laser welding specimens with a preferable joint morphology and mechanical properties. The laser welded auto door with welding joints having an optimized weld length and layout had better quality and performance, and the laser welding process had higher flexibility. (C) 2015 Elsevier Ltd. All rights reserved.