Study on Flow Behavior and Processing Maps of High‐Ti Low‐C Microalloyed Steel during Hot Compression

• Published in: Steel research international 2021-08, Vol.92 (8), p.n/a
• Main Authors: Song, Li-ying, Gao, Xiu-hua, Wang, Ming-ming, Xue, Qi-he, Misra, R. Devesh Kumar, Li, Jin-bo, Wu, Hong-yan, Du, Lin-xiu
• Format: Article
• Language: English
• Subjects: Compression tests; Constitutive models; Dynamic recrystallization; Flow mapping; Grain boundaries; Grain size; High strength low alloy steels; high-Ti low-C microalloyed steels; hot compression; Hot pressing; Microalloying; Precipitates; Process mapping; processing maps; recrystallization; Strain rate
• ISSN: 1611-3683; 1869-344X
• DOI: 10.1002/srin.202100009

Deformation behavior of a high‐Ti low‐C microalloyed steel is studied by isothermal compression tests at temperatures of 800–1100 °C and strain rates of 0.1–10 s−1. The results indicate that the lower the strain rate and higher the temperature of steel, the more likely is the dynamic recrystallization. The stress–strain predicted by the constitutive model, which is established based on the experimental data, are in good agreement with the experimental results. It is noted from the processing maps of steel at various strains that there is instability zone which should be avoided during thermal processing at strain rate less than 1 s−1. The range of 850–1100 °C and 5–10 s−1 strain rate is more conducive to the processing of experimental steel. The movement of grain boundaries, subboundaries, and dislocations is hindered by precipitates in steel. In addition, the mean grain size of austenite at 0.1 s−1 is larger than 5 s−1. This is mainly because low strain rate provides more time for growth of grains. Flow behavior and processing maps of the high‐Ti low‐C microalloyed steel are developed. It is more suitable for hot processing of the steel in the range of 850–1100 °C and 5–10 s−1 strain rates. The precipitates play an essential role during hot compressive deformation. The movement of grain boundaries, subboundaries, and dislocations is hindered by precipitates in steel.