Abstract
The requirement of the high processing, high strength and light weight steel sheet recently rises in automobile industries based on various consideration such as safety, cost reduction, save energy, or even environmental protection. In the present paper, fatigue properties of extra-low carbon steels with different Sn (tin) contents, ranging from 0.002 to 0.22% mass, were investigated. The results show that the fatigue strength by 1×10^7 cycles and hardness number increase with increasing Sn content. In addition, the grain size of materials decreases with increasing Sn content. Fatigue cracks are initiated from the surface of specimens and propagate mainly in an intergranular mode for all of the extra-low carbon steels.
