高Ti-Q550钢中Nb、Ti第二相的析出行为

 采用Thermo-Calc软件、热模拟及扫描电镜研究高Ti-Q550钢中微合金的析出规律。采用Thermo-Calc软件计算不同温度下Nb、Ti的析出规律，钛含量对钢中Nb、Ti析出规律及A3的影响。采用热模拟和扫描电镜研究钢中铌相的析出温度。计算结果表明，钛相的析出温度为1498℃，铌相析出温度为1251℃；随着钢中钛含量的增加，(Nb,Ti)C相析出温度和A3温度升高，但铌在钢中的固溶量降低；当钛的质量分数小于0. 08%时，Ti(N,C)相析出温度随钛含量增加而升高，但当钛的质量分数大于0. 08%时，相析出温度基本不变，钛在钢中的固溶量随钛含量增加而增加。

Precipitation Behaviour of Nb, Ti Second Phase in High Ti-Q550 Steel

The precipitation behavior of microalloy in Q550 steel with high Ti content was investigated by Thermo-Calc software, thermal simulation and SEM. The precipitation behavior of Nb and Ti, the influence of Ti-contents on the precipitation behavior of Nb, Ti and A3 temperature was also studied by Thermo-Calc software. The precipitation temperature of Nb in the steel was measured by thermal simulation and SEM. The calculated results show that the precipitated temperature of Ti phase is 1498℃, and precipitated temperature of Nb phase is 1251℃. With increasing of Ti content, the precipitation temperature of (Nb,Ti)C and A3 temperature increase, but the solution of Nb in the steel decrease. With less than 0. 08% (mass fraction) Ti content, the precipitation temperature of Ti(N,C) increase with increasing of Ti-content, while precipitation temperature is unchanged with more than 0. 08% (mass fraction) Ti content, and the solution of Ti increase with the increasing of Ti content.