Gigacycle Fatigue Properties Evaluation for Martensitic Stainless Steels by Using Ultrasonic Fatigue Tests (Study for Materials with Different Level of Inclusion Size)

• Published in: Nihon Kikai Gakkai ronbunshū. A Vol. 16; no. 8; pp. 1080 - 1086
• Main Authors: Miyamoto, Nobuyuki, Asai, Hiromitsu, Miyakawa, Susumu, Akiniwa, Yoshiaki, Tanaka, Keisuke
• Format: Journal Article
• Language: Japanese
• Published: 01.08.2004
• ISSN: 0387-5008

Gigacycle fatigue properties of two martensitic stainless steels with different level of inclusion size were investigated by using ultrasonic fatigue tests at room temperature. As a result of the tests, the S-N curves for the both materials were straight on the downside. All of the fatigue fracture started from defects at the internal or at the surface. And almost fracture surfaces had facet regions around the defects. There were not facet regions under 2 x 105 cycles for SUS-A with larger level of inclusion and under 5 x 105 cycles for SUS-B with smaller level of inclusion. There were some specimens of SUS-B which didn't break in the regime from 109 to 10' cycles, and which had smaller facet regions than those of the broken specimens. This gives a suggestion that the fatigue limit for internal fatigue fracture exists. For SUS-A and SUS-B, the I area parameter model with ,/ areaF. can explain whether a specimen breaks.