Abstract In this paper, a series of high-cycle fatigue tests were carried out on S280, S350 and LQ550 cold-rolled steel sheets considering different rolling directions and specimen geometries. The S-N curves with a 95% survival probability were derived by fitting the test data using the least squares method. Furthermore, the test results were analyzed from fatigue strength, fatigue damage, and microscopic perspective. We can conclude that the fatigue performance of base metal along the rolling direction (L) is superior to that transverse to the rolling direction (T). S280 and S350 cold-rolled steel sheets exhibit better fatigue performance than LQ550 cold-rolled steel sheet. The above results are attributed to grain size of base metal. Besides, the fatigue performance of cold-rolled steel sheets is better than Q690 high-strength steel and common hot-rolled steel. Under 95% survival probability, the fatigue limit values obtained from test fitting curves are 44% to 67% higher than theoretical calculation values based on AISI 360-2016, AISI S100-2016, and GB50017-2017.
Wang et al. (Thu,) studied this question.