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Evolution of Austenite Grain Size in Continuously Cast Slab during Hot‐Core Heavy Reduction Rolling Process Based on Hot Compression Tests
Author(s) -
Gong Meina,
Li Haijun,
Li Tianxiang,
Wang Bin,
Wang Zhaodong
Publication year - 2018
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201800025
Subject(s) - materials science , dynamic recrystallization , austenite , metallurgy , slab , recrystallization (geology) , microstructure , deformation (meteorology) , grain size , hot working , volume fraction , strain rate , annealing (glass) , composite material , structural engineering , geology , paleontology , engineering
A novel technology called Hot‐core Heavy Reduction (HHR) has been developed to refine the center microstructure of continuously cast slabs, which is rolling at the end of solidification and with large temperature gradient. In this work, plant trials of Hot‐core Heavy Reduction rolling is conducted and show the significant refinement effect on the center microstructure of continuously cast slab. Dynamic recrystallization behavior in Nb–Ti microalloyed slab at high deformation temperature of 1000–1300 °C is further understood using Gleeble‐3800 thermo‐mechanical simulator. The results show that all the austenite grains are largely refined after deformation in hot compression tests. Austenite grains present different morphologies under different deformation temperature. At the temperature of 1100 °C, austenite grains can be significantly refined with increase in the strain and strain rate. While at higher deformation temperature of 1300 °C, austenite grain size cannot be further refined but become coarse to some extent when strain increases to 0.8 and strain rate increases to 10 s −1 . Moreover, the dynamic recrystallization model and austenite grain size model are established in the deformation process. Then, the dynamic recrystallization volume fraction and austenite grain size during HHR rolling process can be well reflected by the established models.