Evaluation of factors affecting the fatigue behavior of butt-welded joints using SM520C-TMC steel

To evaluate the factors affecting fatigue behavior of butt-welded joints, fatigue tests and tension tests were conducted on SM520C-TMC steels with thicknesses ranging from 20 mm to 80 mm. When the fatigue strength of 20 mm thick plate is achieved, the reduction of the fatigue strength of 80 mm thick plate by the present study is improved by over 11.7% to that of previous studies. For fatigue behavior, the reduction in fatigue strength was influenced more significantly by the effect of the geometry of the toe of the weld than by the softening effect. Therefore, the major determinant of fatigue life is the stress concentration factor depending on the shape of the weld zone. These are the same results as those reported in previous research with small-sized tests.