变形温度对ULCB钢动态再结晶的影响

Effect of deformation temperature on dynamic recrystallization of ULCB steel

取得800MPa级和900MPa级ULCB钢，在1100-850℃进行单道次变形的热模拟试验，变形量为40％，应变速率为2s^-1。将应力一应变变化特征和显微组织观察相结合，分析研究变形温度对ULCB钢奥氏体动态再结晶的影响规律。结果表明，温度低于950℃时以形变硬化和动态回复为主，奥氏体形变再结晶主要发生在1000℃以上的高温变形中；奥氏体再结晶百分数随变形温度升高而增加，在1050℃变形后奥氏体再结晶百分数约40％，在1100℃变形后则发生完全再结晶。

The single pass thermo mechanical simulation test has been carried out on 800 MPa grade and 900 MPa grade ULCB steels at 1 100 to 850 ℃ （deformation degree 40 % and strain rate 2 s^-1）. The law of influence of deformation temperature on the dynamic recrystallization of austenite of ULCB steel has been studied and analyzed in combination with observation on the characteristics of change of the stress-strain curve and the microstructure. Results show that at 950 ℃ deformation hardening and dynamic recovery predominate and deformation recrystallization of austenite takes place primarily at over 1 000 ℃ and the fraction of recrystallization of austenite increases with rise of temperature and after deformation at 1 050 ℃ the fraction of austenite recrystallization is about 40 % and after deformation at 1 100 ℃ the complete recrystallization of austenite occurs.