1.序言疲劳裂纹通常从表面开始。金属的疲劳现象是受表面或表面层影响较大的现象之一。所以,疲劳现象受表面状态和环境所左右。其影响,对同一材料来说,在低应力、长时间的试验时较大[1]。因而,在通常的交变速度下,研究一般的分散度较大的疲劳强度时,要得到可靠的实验结果,需要 1. Introduction Fatigue cracks usually start from the surface. Metal fatigue phenomenon is affected by the surface or surface layer of a larger phenomenon. Therefore, the phenomenon of fatigue by the surface conditions and the environment around. Its impact on the same material, in the low-stress, long time test larger [1]. Therefore, under the normal alternating speed, when studying general fatigue strength with large degree of dispersion, it is necessary to obtain reliable experimental results