Tensile shear strength of laser welded lap joints

The dependency of fracture position and maximum load of laser welded lap joints on the weld-bead length and width was clarified through tensile shear test of joints, and a mechanical prediction model for the test results was developed. Joints showed the strength proportional to base metal tensile strength, which have the weld length over 60% of specimen width or the weld width of 2 times of sheet thickness. The developed model, which considers a joint dividing it into the base metal under uniaxial tensile stress, a portion R under stretch bending and the weld metal under shear stress, proved capable of qualitatively predicting the fracture behavior of laser welded lap joints of mild steel sheets at tensile shear test.