Grain coarsening of As-cast austenite and evolution of grain structure during hot charging reheating
ZHENG Hong-guang1, LIU Hua-song2
1. Central Research Institute, Baoshan Iron and Steel Co., Ltd., Shanghai 201900, China; 2. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
Abstract:In order to reveal the evolution of austenite grain structure in continuous casting procedure, the coarsening behavior of austenite grains was studied through the thermal experiments. Due to the influence of precipitates, it was found that the grain growth behaviors of different steel grades are different in high temperature insulation, and the grain size changes little below 1 250 ℃. On this basis, the evolution of austenite grain structure during the reheating process was investigated to reveal the effect of charging temperature on austenite grain structure after slab reheating. The result shows that the grain structure of pre-rolling austenite is consistent with that of pre-cooling when the charging temperature is higher than the pearlite formation temperature. However, when the charging temperature was lower than that, a large number of new fine grains appears after the phase transition. For the latter, abnormal grain growth occurs in the process of continuous reheating, resulting in the eventually larger structure than before cooling.
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ZHENG Hong-guang, LIU Hua-song. Grain coarsening of As-cast austenite and evolution of grain structure during hot charging reheating. CONTINUOUS CASTING, 2020, 39(2): 45-51.
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