1121 浸炭されたオーステナイト系ステンレス鋼 SUS316 の疲労挙動  [in Japanese] Fatigue Behaviour of Carburized Austenitic Stainless Steel SUS316  [in Japanese]

The fatigue behaviour and fracture mechanism of carburized austenitic stainless steel, SUS316,were studied under rotary bending in laboratory air and in 3%NaCl aqueous solution using smooth specimens with two different carburized case depths. A modified carburizing was performed at a temperature below 500℃ in a CO and H_2 gas mixture, Fatigue strength was evaluated and fracture mechanism was discussed on the basis of observation of crack initiation and small crack growth and fracture surface analysis. In laboratory air, the carburized specimens showed considerably higher fatigue strength than the untreated specimens. The fatigue strength in 3%NaCl aqueous solution was the same as that in laboratory air, indicating excellent corrosion resistance of the carburized specimens. Regardless of environment, cracks initiated underneath the carburized case at a very early stage of fatigue life and grew predominantly into the core material with a fish-eye like pattern.