Influence of crack-like surface defects on the fatigue limit of nitrocarburized carbon steel

2018 International Conference on Material Strength and Applied Mechanics

材料科学;力学

Yamada, Y.^1 ; Eto, H.^1 ; Konya, J.^2 ; Takahashi, K.^2

Isuzu Motors LTD, 8 Tsuchidana, Fujisawa-shi, Kanagawa

252-0881, Japan^1

Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama

240-8501, Japan^2

关键词: Bending fatigue limit;    Bending fatigue tests;    Crack-like surface defects;    Fatigue Limit;    Medium-carbon steels;    Nitrocarburized;    Nitrocarburized steels;    Surface cracks;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/372/1/012005/pdf
DOI  :  10.1088/1757-899X/372/1/012005

来源: IOP

【 摘 要 】

The aim of this study was to evaluate the influence of surface crack on the bending fatigue limit of nitrocarburized steel. Semicircular slits with depths of 0.040, 0.075, and 0.100 mm were introduced on the surface of nitrocarburized medium carbon steel specimens to simulate the presence of small cracks. Bending fatigue tests were performed at room temperature in air with the stress ratio R = -1. It was observed that the fatigue limit decreased as the depth of the slit increased. The acceptable crack size was estimated based on fracture mechanics. The predicted acceptable crack size was consistent with the experimental result. Therefore, the acceptable crack size of nitrocarburized carbon steel could be predicted via analysis based on fracture mechanics.