摘要
通过Gleeble-2000D热/力模拟试验机对Nb微合金化齿轮钢18CrNiMo7-6进行了热压缩试验,研究了试验钢在变形温度为900~1100℃、应变速率为0.01、0.1、1和10 s^(-1)下的热塑性,计算了热变形激活能,并构建了峰值应力的本构方程。结果表明,试验钢的应力-应变曲线具有典型的动态再结晶特征,动态再结晶为主要的软化机制;在相同应变速率下,变形温度越高,热塑性越好,动态再结晶是一个热激活过程;通过Thermo-calc热力学软件计算得到,试验钢中主要存在的碳化物为M_(23)C_(6)和NbC,其中NbC的全固溶温度达到1180℃,Nb主要以NbC析出相为主,NbC在不同变形温度下的析出含量分别为0.0343%、0.0322%、0.0289%、0.0236%及0.0156%;采用Arrhenius双曲正弦函数建立了试验钢的峰值应力本构方程,确定了热变形激活能为Q=344.55 kJ/mol,模型预测出的峰值应力与实测峰值应力平均误差1.5%。
Hot compression test was subjected on Nb microalloyed gear steel 18CrNiMo7-6 by Gleeble-2000D thermal simulation testing machine to investigate the thermoplastic properties of the tested steel at deformation temperatures between 900-1100℃and strain rates at 0.01,0.1,1 and 10 s^(-1),respectively.The activation energy of thermal deformation was calculated,and the constitutive equation of peak stress was constructed.The results show that the stress-strain curves of the tested steel exhibits typical dynamic recrystallization characteristics,which is the main softening mechanism.At the same strain rate,the higher the deformation temperature,the better the thermoplastic properties,and dynamic recrystallization is a thermal activation process.The main carbides present in the tested steel are calculated by using Thermo-calc thermodynamic software to be M_(23)C_(6),and NbC.The full solution temperature of NbC reaches 1180℃,and Nb is mainly composed of NbC precipitates.The precipitation content of NbC at different deformation temperatures is 0.0343%,0.0322%,0.0289%,0.0236%and 0.0156%,respectively.The peak stress constitutive equation of the tested steel is established by using Arrhenius hyperbolic sine function.The activation energy of hot deformation is determined to be Q=344.55 kJ/mol,and the average error between the peak stress predicted by the model and the measured peak stress is 1.5%.
作者
杨少朋
周大元
王雅倩
景宏亮
吴胜付
胡芳忠
汪开忠
王毛球
Yang Shaopeng;Zhou Dayuan;Wang Yaqian;Jing Hongliang;Wu Shengfu;Hu Fangzhong;Wang Kaizhong;Wang Maoqiu(Institute for Special Steels,Central Iron and Steel Research Institute Company Limited,Beijing 100081,China;Technology Center,Ma'anshan Iron and Steel Co.,Ltd.,Ma'anshan Anhui 243000,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2023年第6期178-185,共8页
Heat Treatment of Metals
基金
工信部工业强基项目(TC180A3Y1/分包号:14)。
