通过对新型TiC 增强耐磨钢进行在线回火热模拟试验，采用扫描电子显微镜(SEM) 结合能谱INCA Feature 功能分析了回火温度对TiC 粒子体积分数和尺寸分布的影响。结果表明：与未经热处理的试验钢相比，回火后钢中TiC 析出相的体积分数有所增加。但温度较低时(500 ℃)，析出相增加不明显且小尺寸粒子(1~3 μm) 所占比例偏低，大于5 μm 的析出相所占比例高。随回火温度的增加，高于550 ℃后，析出相总量显著提高，同时尺寸分布在1~3 μm 范围内的粒子所占比例明显增加，650 ℃回火时，达到72% 左右。且粒子的最大尺寸及其比例均下降。因此，500 ℃回火主要有利于TiC 粒子的粗化长大，而温度超过550 ℃后则TiC 粒子的形核、析出过程更加显著，粒子尺寸较小。

Effect of tempering temperature on the volume fraction and size distribution of TiC particles in TiC strengthened antifriction steel was analyzed by on-line tempering thermal simulation technique, SEM and INCA Feature. The results show that the volume fraction of TiC in the steel increases after tempering. But at 500 ℃, the increase is not obvious and the proportion of TiC particles with small size (1—3 μm) is low. What’s more, the proportion of TiC particles with size larger than 3 μm, especially larger than 5 μm, is very high. On the contrary, after tempering temperature exceeds 550 ℃, the summation of precipitations and the proportion of TiC particles with small size (1—3 μm) increase rapidly. When tempering temperature is 650 ℃, the proportion of TiC particles with small size (1—3 μm) reaches about 72%. In addition, both the largest size and its proportion of precipitations drop. So tempering at 500 ℃ is propitious to the growth of TiC particles. While when tempering temperature is larger than 550 ℃, it is beneficial to the nucleation and precipitation of TiC particles, which makes TiC particles small.