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本文在544根L207E柴油机球铁曲轴断裂统计资料的基础上,对其中521根应用数理统计法,求得现用曲轴的一般平均使用寿命。并根据对涉及亚蠕变范围内疲劳裂纹起始机理的理解,进一步对曲轴断裂的性质、部位及在各轴位上分布机率之影响因素作了扼要的讨论分析。然后,从疲劳裂纹的亚临界扩展特性与一般性规律出发,结合断裂力学观点,对球铁曲轴的断裂进行了初步分析和材料的评定。由此,提出延长曲轴使用寿命的若干途径。
Based on the statistical data of fracture of 544 L207E diesel ductile iron crankshafts, 521 of them are analyzed by mathematical statistics, and the average service life of the existing crankshafts is obtained. Based on the understanding of the initiation mechanism of fatigue crack in the range of sub-creep, the properties of the crankshaft fracture, the location and influencing factors of the distribution probability in each axis are further discussed and analyzed. Then, based on the subcritical propagation characteristics and general laws of fatigue crack, the fracture of the ductile iron crankshaft was analyzed and the materials were evaluated based on the fracture mechanics. Thus, several ways to extend the service life of crankshafts are proposed.