汽车曲轴用钢中碳氮化钒的析出行为研究

Research on Precipitation of Vanadium Carbonitride in Automobile Crankshaft Steel

采用应力松弛法在Gleeble-3500热模拟试验机上研究了汽车曲轴用钢中碳氮化钒在奥氏体中的析出行为。研究结果表明:在ε=15%、ε=0.1 s^(-1)的条件下,当钢中氦含量为0.013%时,碳氮化钒在奥氏体中的最快析出温度为845℃,从析出开始到结束仅需65 s;且当氮含量由0.007%增加到0.023%时,碳氮化钒的最快析出温度和开始析出时间分别为890℃和6.8 s。基于Johnson-Mehl-Avrami方程,计算了V-N微合金钢中V(C,N)在奥氏体中的析出动力学,理论计算得出的最快开始析出温度与实验结果相吻合。

The precipitation behavior of Vanadium Carbonitride V(C,N)in austenite of automobile crankshaft steel is researched on Gleeble-3500 by the tensile stress relaxation method.The result shows that under the condition of ε=15%,ε0.1 s^(-1),the fastest precipitation temperature of V(C,N)(when N%=0.013%)in austenite is 845℃,it only takes 65 s to precipitate from beginning to end.When N%increases from 0.007%to 0.023%,the fastest precipitation temperature is 890 ℃,and precipitation start time is 6.8s.Based on Johnson-Mehl-Avrami equation,precipitation kinetics of V(C,N)in austenite of V-N micro-alloy steel is calculated and the theoretical fastest precipitation temperature and precipitation start time are in line with the experiment results.