Dissimilar fiber laser welding between dual phase and high strength low alloy steels

Abstract

With increasing use of dual phase steels in the automotive industry, it is important to have an understanding of how they behave when they are welded to conventional high strength low alloy steels (HSLA). Fiber laser welded dissimilar joints between DP980 and HSLA steels were evaluated in tension at low temperature (-40°C), room temperature (25°C), elevated temperature (180°C), and in fatigue under different welding conditions. Triple dissimilar welds were tested in various combinations and with different types of protective zinc coatings to determine the effect that coatings play on the tensile and fatigue behaviour. Lastly, an analysis was done on how the change in DP980 chemistry could affect the final mechanical properties of their welded joints.