回火温度对TiC增强耐磨钢TiC粒子析出行为的影响

通过对新型Ti C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Ti C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Ti C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(1~3μm)所占比例偏低,大于5μm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1~3μm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Ti C粒子的粗化长大,而温度超过550℃后则Ti C粒子的形核、析出过程更加显著,粒子尺寸较小。

Effect of tempering temperature on precipitation behavior of TiC particles in TiC strengthened antifriction steel

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 ??m) is low. What??s more, the proportion of TiC particles with size larger than 3 ??m, especially larger than 5 ??m, 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 ??m) increase rapidly. When tempering temperature is 650 ??, the proportion of TiC particles with small size (1??3 ??m) 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.