油環境下におけるS35C焼なまし平滑材の微小疲労き裂伝ぱ挙動
1992 年 58 巻 547 号 p. 348-352
詳細
1992 年 58 巻 547 号 p. 348-352
In order to clarify the small-crack growth behavior in oil environments, rotating bending fatigue tests of annealed 0.34 % C steel plain specimens with a small blind hole are carried out in environments of paraffinic base oils having 4 viscosities η. The cycle frequencies f used are 12.5, 25 and 50Hz. The main results obtained are as follows : the effect of oil viscosity η on the growth rate of a small crack dl/dN depends on the cycle frequency. The relation between the crack propagation life and the term ηf is approximated by a smooth curve. The maximum propagation life appears at around ηf=2×10-3 m2/s2. The existence of ηf which prodce the maximum propagation life seems to generate the dissimilar effect of η on dl/dN under the different values of f. dl/dN of a small crack is determined uniquely by the term σnal
