3-Dimensional Observation of Fatigue Crack Propagation on Spot Welded Joints using High Strength Steel

Abstract

In this study, in order to investigate the fatigue characteristics of the spot welded joints using the high strength steel, fatigue tests were conducted and internal fatigue crack behavior around the spot area was observed in detail. Test results showed that spot welded joints had the low fatigue strength compared with the tensile strength of base metal and spot welded joints. Moreover, it was clarified spot welded joints used in this study require many cyclic loading to initiate the fatigue crack. Furthermore their fatigue crack propagation indicates the similar behavior in major part of life independently of the stress level.