Static and fatigue strength of laser-welded lap joints in thin steel sheet

Summary

Offering the advantages of high welding speed and low heat distortion, laser welding is an attractive process for joining thin steel sheet. This paper describes an investigation of the static and fatigue strength of laser-welded lap joints in thin steel sheet with different sheet thicknesses and tensile strengths and compares the results with those obtained for spot-welded joints. To evaluate the static strength of the joints, a method for estimation of the joint strength and fracture mode is established. To evaluate the fatigue strength of the joints, the mixed-mode fracture-mechanics criterion of Erdogan and Sih is used, giving good characterisation of the fatigue strength, including that of the spot-welded joints.