EFFECTS OF RESIDUAL STRESSES ON THE STATIC AND FATIGUE STRENGTH OF LASER-WELDED LAP JOINTS WITH DIFFERENT WELDING SPEEDS |
R. A. SINDHU1, M. K. PARK1, S. J. LEE1, K. D. LEE2 |
1Myongji University 2Institute for Advanced Engineering |
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ABSTRACT |
This study was conducted to determine whether the different residual stresses caused by different welding speeds affect the static and fatigue strength of laser-welded lap joints. Residual stresses in STS301L laser-welded lap joints of different thicknesses under two laser-welding speed conditions, 4.1 m/min and 5.1 m/min, were evaluated with the incremental hole-drilling strain gage method at the middle of the heat-affected zone (HAZ). Then, static and fatigue tests were performed. The results show that higher static and fatigue strengths were obtained from the specimens welded with a 4.1 m/ min welding speed than from the specimens welded at 5.1 m/min. The main difference was due to the compressive principal residual stress magnitude and its orientation near the HAZ. Also, the micro-hardness profile along the failure interface was measured to verify the static and fatigue failure behavior. |
Key Words:
Residual stress, Welding speed, Laser-welded lap joint, Static strength, Fatigue strength |
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