Thermodynamics and industrial practice of non-metallic inclusions formation during solidification and cooling of Q195 hot rolled strip
ZHANG Xu-hui1, WANG Ju-jin2, KONG Xiang-yu1, MENG Run-ze1, REN Ying2
1. Tangshan Xinbaotai Iron and Steel Co., Ltd., Tangshan 064000, Hebei, China; 2. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
Abstract：In order to control the transformation of non-metallic inclusions in Q195 steel during solidification and cooling, the transformation of inclusions in practical production process was studied by ASPEX automatic scanning electron microscope, and the thermodynamic principle of the transformation was calculated by FactSage software. The results show that inclusions in molten steel of Si-Mn-Al deoxidized Q195 hot rolled strip are mainly SiO2-MnO-Al2O3. There is a sharp increase in sulfide inclusions in bloom after solidification and cooling. An increase of SiO2 and an decrease of MnO in oxide inclusions can also be detected. The composition of inclusions in steel have obvious corresponding relationship with the size of inclusions, which is that the content of Al2O3 in inclusions increase with diameter of inclusion, while the content of SiO2 decreases. As the size of the inclusion in bloom decreases, content of sulfides and SiO2 in oxide inclusions have a dramatic increase. Thermodynamic calculation by FactSage indicates that SiO2, Mn2Al4Si5O18 and MnS precipitate during solidification and cooling of steel, and the size of precipitated phase is generally small, which results in the increase of content of SiO2 and MnS in small size inclusions. Thermodynamic theoretical calculation can explain the transformation of inclusion composition duiring solidification and cooling process.
张旭辉, 王举金, 孔祥玉, 孟润泽, 任英. Q195热轧带钢凝固冷却过程非金属夹杂物生成热力学及工业实践[J]. 连铸, 2020, 39(1): 61-65.
ZHANG Xu-hui, WANG Ju-jin, KONG Xiang-yu, MENG Run-ze, REN Ying. Thermodynamics and industrial practice of non-metallic inclusions formation during solidification and cooling of Q195 hot rolled strip. CONTINUOUS CASTING, 2020, 39(1): 61-65.
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