根据铬元素质量分数为1. 6%时垂直截面富铁端的Fe-Cr-C三元相图和碳、铬元素高温扩散性能,分析了凝固结晶时材料中碳含量分布的变化过程,说明了碳化物不均匀性缺陷的形成机理,并讨论了碳化物不均匀性缺陷对轴承接触疲劳寿命的影响。结果表明:GCr15轴承钢的碳化物不均匀性缺陷包括网状碳化物、带状碳化物和碳化物液析等,产生原因为GCr15钢液相线和固相线间隔较大,导致元素偏析明显,在凝固结晶过程中产生了碳化物不均匀性。

According to the vertical section of Fe-Cr-C ternary phase diagram with 1. 6% mass fraction of chromium and the high-temperature diffusion properties of carbon and chromium, the change process of carbon content distribution in the material during solidification and crystallization was analyzed, the formation mechanism of carbide inhomogeneity defects was explained, and the influence of carbide inhomogeneity defects on bearing contact fatigue life was discussed. The results show that the carbide inhomogeneity defects in GCr15 bearing steel included network carbide, band carbide and carbide-eliquation. The gap between liquidus and solidus of GCr15 steel was large, which caused obvious element segregation, and the carbide inhomogeneity defects were produced during solidification and crystallization.