Mn-Cr齿轮钢动态再结晶行为及组织演变  

Dynamic recrystallization behavior and microstructure evolution of a Mn-Cr gear steel

作　　者：王秉新[1] 周存龙[1] 徐旭东[1] 刘相华[1] 王国栋[1] 

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室

出　　处：《材料科学与工艺》2006年第4期377-380,共4页Materials Science and Technology

基　　金：国家重点基础研究发展规划项目(G2000067208-4)

摘　　要：采用Gleeble 1500热模拟试验机研究了-Mn—Cr齿轮钢在变形速率为0．1—1s^-1、变形温度为900—1150℃、原始奥氏体晶粒尺寸为70—150μm条件下的动态再结晶行为及再结晶奥氏体晶粒尺寸的变化规律．实验结果表明，Mn—Cr齿轮钢在温度较高，应变速率较低及原始奥氏体晶粒较细的情况下变形时，表现出典型的动态再结晶行为．再结晶发生的条件为Zener—Hollomon参数小于某一临界值（Zc）．再结晶晶粒按晶界突出机制形核．通过回归分析，确定该齿轮钢的再结晶激活能为378．6kJ／mol，应力指数为5．8．Z参数控制形变储存能，因而唯一地决定动态再结晶晶粒尺寸Ds，二者符合关系式Ds=1．3×10^5Z^-0.25．Using a Gleeble 1500 thermal simulator, the dynamic recrystallization（DRX） behavior and changes of DRX grain size for a Mn - Cr type gear steel have been investigated at 900 - 1150℃ , with strain rates of 0. 1 - 1 s^-1, and initial grain sizes of 70 - 150 μm. The experimental results show that the Mn - Cr gear steel exhibits a typical DRX behavior at higher deformation temperatures, lower strain rates and smaller initial grain sizes. The DRX takes place when Zener - Hollomon parameter （Z） is less than a critical value （Zc）. The DRX grains are formed by the bulging mechanism. By regression analysis, activation energy and stress exponent were determined to be 378.6 kJ/mol and 5.8 respectively. The DRX grain size Ds is determined only by Z because Z controls the stored energy. The equation Ds = 1.3 × 10^5Z^-0.25 gives the relation between Ds and Z.

关 键 词：Mn-Cr齿轮钢 热变形条件 动态再结晶 奥氏体晶粒尺寸 

分 类 号：TG111.7[金属学及工艺—物理冶金]