胀断连杆用高钒中碳钢的动态再结晶行为

Dynamic Recrystallization Behavior of Medium-Carbon Vanadium-Microalloyed Steel for Fracture Splitting Connecting Rod

利用Gleeble 3800热模拟试验机进行单道次压缩试验,研究了1种新型胀断连杆用高钒中碳钢37MnSiVS在900~1 150℃温度区间和0.1~10s-2变形速率条件下的动态再结晶行为。结果表明：试验料的热变形特征与传统的中碳微合金钢基本一致,较高的温度和较低的应变速率有利于发生动态再结晶。试验料在变形温度低于1 000℃时开始发生再结晶的时间进一步延长。透射电镜（TEM）观察结果表明,试验料中的钒主要以固溶态的形式存在于奥氏体中,从而影响奥氏体的动态再结晶行为。所获得的试验料的热变形激活能为364.9kJ/mol,并得出了其热变形方程及动态再结晶晶粒尺寸与Zener-Hollomon参数之间的关系式。

Single compression tests were carried out using Gleeble 3800 thermal simulator in the temperature range of 900--1 150℃ and strain rates of 0.1--10s^-1 to investigate the dynamic reerystallization behavior of a new vana- dium mieroalloyed medium carbon steel 37MnSiVS for fracture splitting connecting rod. The results show that the hot deformation behavior of the tested steel is similar to that of conventional medium-carbon microalloyed steels and dynamic recrystallization is easier to occur at higher deformation temperature and lower strain rate. The start ing time of dynamic recrystallization is significantly prolonged when deformation temperature is lower than about 1 000 ℃. TEM observation reveals that vanadium is mainly in dissolved condition in austenite and thus affects the dynamic reerystallization behavior of the tested steel. The hot deformation activation energy of the tested steel is 364.9kJ/mol. Furthermore, the hot deformation equation and the relationship between the sizes of dynamic re- crystallization grains and Zener Hollomon parameter were obtained.