Comparison of Amplitude Dependent Fatigue Lives of Resistance Spot Welded Dual Phase Steels
AbstractBending fatigue lives of resistance spot welded (RSW) joints using commercial DP600 and DP1000 advanced high strength automotive sheets were compared in this study. Advanced high strength steels, especially DP600 and DP1000 steels which are used in this study, are the most important metal materials in which today's automotive body and attachment parts are produced. The materials used for the manufacture of the vehicle under dynamic conditions need to be identified of their all features are vey important. The literature has mainly focused on axial fatigue. Fatigue lives of base material and resistance spot welded joints obtained from different welding parameters were investigated by using two different high strength dual phase steel. It was seen that as the welding current increased and the electrode pressure increased up to a certain value as in the axial fatigue, the bending fatigue life was increased from the results of this study. Direct proportional relationship was obtained between the weld nugget size and fatigue life. 7 kA-4 bar (DP600) and 7 kA-3 bar (DP1000) welding parameters yielded better fatigue life. DP1000 and DP600 steel sheet samples have similar fatigue life values in low cycle fatigue. It was also seen that DP600 steel had better fatigue life than DP1000 in high cycle fatigue.