在变形温度600～950 ℃、应变速率1 s-1的条件下对碳质量分数分别为0.26%, 0.33%, 0.42%的含钒微合金钢进行了应力松弛试验, 得到了其应力松弛曲线和V(C,N)的析出动力学(PTT)曲线, 结合显微组织分析了V(C,N)析出规律。结果表明: V(C,N)的析出会阻碍试验钢中奥氏体再结晶, 减缓应力的下降; 奥氏体中V(C,N)的PTT曲线呈S形, 在900 ℃时V(C,N)析出最快; 试验钢中碳含量的增加加快了V(C,N)的析出速率, 但不影响其最快析出温度, 含碳量最高的试验钢具有最短的开始析出时间,为7.5 s。

The stress relaxation experiments under the conditions of deformation temperature of 600-950 ℃ and strain rate of 1 s-1were conducted on the vanadium microalloyed steels with different carbon content of 0.26wt%, 0.33wt% and 0.42wt%, and then the stress relaxation curves of the steels and the precipitation kinetics (PTT) curves of V(C,N) were obtained. Combining with the microstructure, the precipitation law of V(C,N) was analyzed. The results show that the precipitation of V(C,N) inhibited the recrystallization of austenite in the tested steels, resulting in the decrease of stress. The PTT curves of V(C,N) precipitates in austenite showed a S-like shape. The precipitation rate of V(C,N) was the fastest at 900 ℃. The increase of carbon content in the tested steels accelerated V(C,N) precipitation rate, but had no effect on the temperature with the fastest precipitation rate. The tested steel with the highest carbon content had the shortest precipitation start time of 7.5 s.