Ferrite transformation law of Q&P steel during cooling process
HE Fang1, WANG Rui-zhen1, YANG Cai-fu1, JIA Ya-fei2, WU Yan-xin3, LI Mian3
1. Institute of Structural Steels,Central Iron and Steel Reserch Institute, Beijing 100081, China; 2. Technical Center,Handan Iron and Steel Group Co. , Ltd. , Handan 056015, Hebei, China; 3. Institute of Engineering and Technology, University of Science and Technology Beijing, Beijing 100081, China
Abstract：In order to study the ferrite transformation of Q&P (quenching and partition steel) during cooling,the ferrite phase transformation thermal expansion data of different cooling rates of Q&P steel with chemical composition 0.2%C,1.25%Si,2.0%Mn was measured on the thermal dilatometer. The soaking hot treatment process was 846 ℃ soaking for 200 s. The thermal expansion data were treated as the relationship between the phase volume fraction and temperature by lever law. The ferrite phase volume fraction and ferrite grain size were measured by optical microscope. Based on the mixed model,the phase boundary migration rate of ferrite was obtained. Combined with the starting temperature of transformation,the end temperature of transformation was calculated by the mixed model. The evolution process of ferrite grain size in the process of transformation was discussed. The calculated value of ferrite grain size was in good agreement with the measured value. The error between the calculated value and the measured value of the end temperature of transformation was within ±15 ℃. The obtained ferrite transformation law can be used to control the ferrite volume fraction in the cooling process of Q&P steel.
何方, 王瑞珍, 杨才福, 贾亚飞, 吴彦欣, 李免. Q&P钢在冷却过程中铁素体的相变规律[J]. 钢铁, 2020, 55(9): 81-85.
HE Fang, WANG Rui-zhen, YANG Cai-fu, JIA Ya-fei, WU Yan-xin, LI Mian. Ferrite transformation law of Q&P steel during cooling process[J]. Iron and Steel, 2020, 55(9): 81-85.
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2020, Vol. 55 
