一种新型冷轧工作辊用高速钢的热变形行为

Hot deformation behavior of a novel high speed steel for cold mill work roller

采用Gleeble-3500热模拟试验机对一种新型冷轧工作辊用高速钢进行了热压缩变形试验,研究了该钢在900～1150℃、应变速率为0.01～10 s-1条件下的动态再结晶行为,测量了该钢的应力-应变曲线并观察了其典型的微观组织,建立了Z参数表达式、热变形方程、峰值应力和峰值应变与Z参数的关系及动态再结晶模型图。结果表明:冷轧工作辊用高速钢的应力-应变曲线表现为动态再结晶型;其热变形激活能为541.4 kJ/mol;峰值应力、峰值应变与Z参数近似成指数关系;随着Z参数的增大,发生动态再结晶的临界应变εp和发生完全再结晶的应变εs均增加。

Hot compressive experiment of a novel high speed steel for cold mill work roller was carried out on a Gleeble-3500 thermo- simulation machine. The dynamic recrystallization behavior of the steel between 900 to 1150 ℃ and with strain rates from 0.01 to 10 s-1 was investigated. The stress-strain curves were measured and the typical microstructure were observed. Meanwhile, the Zener-Hollomon parametric equation, the thermal deformation equation, the relationship between the peak stress, peak strain and Z parameter and dynamic recrystallization diagram were established, respectively. The results show that the stress-strain curve of the high speed steel for cold mill work roller exhibits dynamic recrystallization characteristics and its thermal deformation activation energy is 541.4 kJ/mol. The peak stress, peak strain and Z parameter follow an exponential law. With the increase of Z parameter, the critical strain εp for dynamic reerystallization occurring and strain εs for complete dynamic recrystallization increase together.