硫对超高强度钢300M高周疲劳性能的影响

对高硫和低硫300M钢的显微组织和力学性能进行了系统研究，重点分析了硫含量对300M钢中夹杂物特征及高周疲劳寿命的影响机理。研究发现，硫含量的增加会大大降低300M钢的高周疲劳寿命。硫含量的增加会提高MnS夹杂物的析出温度及析出数量，提高试样次表层出现大尺寸MnS夹杂物的概率，大大降低高周疲劳裂纹萌生的难度，进而降低300M钢的高周疲劳寿命。

Influence of sulfur on high cycle fatigue property of 300M ultra-high strength steel

Microstructure and mechanical properties of 300M steels with high sulfur and low sulfur contents were systematically studied, and the influencing mechanisms of sulfur content on inclusion characters and high cycle fatigue life of the 300M steel were emphatically analyzed. The results indicate that high sulfur addition will dramatically decrease the high cycle fatigue life of 300M steel. Higher sulfur addition will increase the precipitating temperature and precipitating content of MnS inclusion, then the probability of large size MnS inclusions appearing in the subsurface of the specimen is increased, and the difficulty of high cycle fatigue crack initiation is greatly reduced, thus reducing the high cycle fatigue life of 300M steel.