2035 高周波焼入れした機械構造用鋼のギガサイクル疲労特性(S11-3 表面処理・応力比等の影響,S11 金属材料の超高サイクル疲労特性の解明)  [in Japanese] 2035 Giga-Cycle Fatigue Properties of Induction Hardened Structural Steels  [in Japanese]

Giga-cycle fatigue tests were conducted for induction hardened S40C carbon steels. The induction hardened S40C steels revealed fish-eye fractures whose origins were mostly a TiN and entirely an Al_2O_3 in case of heat A and B, respectively. When ultrasonic fatigue tests were compared with rotating bending, focusing on results of fish-eye fracture, the heat B results showed good agreements. Although the heat A results showed difference, it was small enough to be in scattering of the heat B results. Effects of pre-treatments before the induction hardening were also investigated in heat B, resulting in showing no influence of the pre-treatment condition.