Static and fatigue performance of weld bonded dual phase steel sheets

Abstract

Lap joints of dual phase steel sheets of 1·0 mm were prepared by adhesive bonding, spot welding and weld bonding processes using a one component epoxy base structural adhesive. Mechanical properties of the joints were evaluated by tensile shear and fatigue tests. The size of the weld nugget for both spot weld and weld bond was measured for different welding parameters (current, time) and compared. For identical welding parameters, weld bonded nuggets exhibit higher nugget diameter. Tensile shear strength of weld bonded joints is 40 and 58% higher than spot welded joints and 15 and 39% higher than adhesive bonded joints and for DP590 and DP780 steels respectively. Considering 10⁶ cycles, the endurance limit of weld bonded joint is much higher than spot welded joint but smaller than adhesive bonded joints. Overall the performance of weld bonded joints is superior to those of resistance spot welding.