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Title | Fatigue Strength Predictions of Notched Specimens of Spring Steel |
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Author | Fumio TAKAHASHI 1) Akira TANGE 1) Yoshiki ONO 1) Kotoji ANDO 2) |
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Abstract | This paper presents the study on fatigue strength and fatigue life predictions of surface notched specimens of
spring steel. The validity of the fatigue limit prediction and the fatigue crack growth prediction based on
Haddad's equation, where the hardness of material and stress ratio were taken into considerations, were
studied, compared with the experimental results. The specimens with semicircular notch by electrical
discharge machining were prepared. The conditions of tests were without decarburization, with
decarburization and with shot peening. The main results can be summarized below:
¡Ê1¡ËThe calculated fatigue limits were slightly smaller than the experimental results for the without
decarburization specimens. It can be said that the fatigue limit prediction is evaluated within the safe side
in this case.
¡Ê2¡ËThe calculated fatigue limits were between the experimental fracture and non-fracture results for the
decarburized specimens. Therefore, the fatigue limit prediction can be said to be effective.
¡Ê3¡ËThe fatigue limit prediction for the shot peeed specimens was evaluated within the safe side. It can be
said that the prediction is effective.
¡Ê4¡ËThe calculated fatigue crack growth behavior with da/dN-¦¤K diagrams showed good agreements with
experimental results.
¡Ê5¡ËThe calculated fatigue life was slightly shorter than the experimental fatigue life without decarburization
on the S-N curves. The calculated fatigue life showed good agreements with the experimental results
with decarburization. Therefore, it can be concluded that the fatigue crack growth prediction is very
effective. |
Ãø¼Ô¤Î½ê° | 1)ÆüËÜȯ¾òê¡¡£²¡Ë²£É͹ñΩÂç³Ø |
Belonging | £±¡ËNHK SPRING CO., LTD.¡¡£²¡ËYokohama National University |
Key Words | Fatigue limit, Fatigue life, Notched specimens, Decarburization, Shot peening |