超高强度Ti微合金复相钢再结晶行为研究

Recrystallization behavior of ultra-high strength low carbon micro-alloyed Complex Phase steel

本文采用单道次和双道次压缩实验研究超高强度微合金Ti复相钢(CP钢)在变形温度为800～1150℃,应变速率为0.1～10 s-1条件下的再结晶行为,观察了各种变形条件下的对再结晶行为的影响.研究发现,高的钛含量明显提高了动态再结晶和静态再结晶的激活能.通过扫描电镜发现,细小氮化钛和碳化钛分布在奥氏体基体及晶界处,其颗粒大小在50——200nm之间.动力学曲线和金相表明,实验钢的未再结晶的临界温度介于1000-950℃之间.实验钢动态再结晶的峰值应要明显高于一般碳锰钢.基于动力学曲线,建立了实验钢静态再结晶的本构方程.

The dynamic and static recrystallization behavior of a 0.11%（in mass） Ti-microalloyed complex phase steel（CP steel） were studied by single-hit hot compression and double-hit isothermal hot compression tests.The influences of different deforming temperature,strain rate,strain and different holding times on microstructure transformation were investigated.It was found that the high contain of micro-alloyed element Ti improved the deformation activation energy of dynamic and static recrystallization.The precipitations was fine Ti（CN） located at the grain boundary and the austenitic matrix,and the size of precipitations is about 50nm-200nm.The calculated kinetic results and microstructures show that the no-recrystallization temperature（Tnr） is about 950℃.Based on the stress-strain curves,a kinetic equation was estabilished to predict the static recrystallization fraction of Ti-microalloyed steel.