Relationship among fatigue life, inclusion size and hydrogen concentration for high-strength steel in the VHCF regime

摘要

Based on experimental data and from the viewpoint of linear elastic fracture mechanics (LEFM), this paper proposes the relationship among fatigue life, N_f, nonmetallic inclusion size, r_0, and hydrogen concentration in steel, C_H, for high-strength steels in the very high cycle fatigue (VHCF) regime. Fatigue life, depending on the inclusion size and hydrogen concentration, decreases significantly with inclusion size and/or hydrogen concentration increasing. For the high-strength spring steel 60Si2CrV, if the inclusion size is reduced by one-third or one-half, the fatigue life will be up to about 10 or 100 times, respectively. Finally, the relationships of fatigue strength and fatigue life with inclusion size were compared.