Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 19 No. 6 December 2009|
（1. Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China;
2. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:Processing maps for a medium carbon V-N microalloyed steel(designated as VN steel) and a medium carbon V-N bared steel(designated as Non-VN steel) were developed to study the hot deformation behavior and the influence of vanadium and nitrogen, in the temperature range of 750−1 100 ℃ and strain rate range of 0.005−30 s−1. Experimental results show that the processing map for the VN steel exhibits two dynamic recrystallization and three instability domains, while that for the Non-VN steel has one dynamic recrystallization and three instability domains. The instability domains of VN steel are larger than those of the Non-VN steel, and the VN steel is easier to be unstable when being hot deformed at high temperature and high stain rate. The addition and precipitation of vanadium and nitrogen can hinder the dynamic recrystallization. Compared with the Non-VN steel, the VN steel has higher dynamic recrystallization critical strain and the corresponding stress.
Key words: medium carbon V-N microalloyed steel; hot deformation; processing map; dynamic recrystallization