中南大学学报(英文版)
中南大學學報(英文版)
중남대학학보(영문판)
JOURNAL OF CENTRAL SOUTH UNIVERSITY OF TECHNOLOGY(ENGLISH EDITION)
2015年
9期
3265-3274
,共10页
袁晓虹%郑善举%杨卯生%赵昆渝
袁曉虹%鄭善舉%楊卯生%趙昆渝
원효홍%정선거%양묘생%조곤투
high-alloy steel%Z parameter%grain size refinement%carbides%dynamic recrystallization (DRX) mechanism
The dynamic recrystallization and carbides precipitation of the Cr-Co-Mo-Ni bearing steel were investigated by hot compression tests performed at temperatures ranging from 850 °C to 1080 °C with strain rate of 1?20 s?1. The activation energy (Q) for the tested steel is calculated to be around 682.99 kJ/mol at a deformation strain of 0.6. Microstructural analysis by SEM shows that the dynamic recrystallization (DRX) behavior is dependent sensitively on the deformation strain, temperature and strain rate, while an exponential relationship between DRX grain size and Z parameter is obtained from the computational formula. Moreover, the M6C-type carbides (<1μm) act as the main prohibitor of grain coarsening, and the polynomial regression relationship between them is worked out. With electron backscatter diffraction (EBSD) observation, DRX is the main nucleation mechanism responsible for the formation of new grains during hot compression. In conclusion, the interaction between DRX affected by hot deformation parameters and carbides precipitation determines the ultimate grain size refinement.