Abstract
DP980 dual phase and high strength low alloy (HSLA) steels were welded, using fibre laser, with varying amounts of concavity to determine its effects on the tensile and fatigue properties. Higher concavity, 25 to 35%, was observed to reduce the tensile strength of the DP980 welds, while not affecting the tensile strength of HSLA welds. All welds exhibited lower fatigue resistance compared to their base metals. However, DP980 welds with higher concavity (25 to 35%) exhibited even lower fatigue resistance while HSLA welds showed similar performance regardless of changes in concavity. Concavity could be minimised by reducing welding power and increasing the welding speed.
This research was funded by the International Zinc Association, USA; AUTO21, Canada’s automotive research and development program, Initiative for Automotive Manufacturing Innovation (IAMI). The authors are thankful to Dr Scott Lawson for the valuable discussion. The help of ArcelorMittal Dofasco Inc. in Hamilton, Canada in providing materials for this study is highly acknowledged.