1. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China; 2. State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, Hebei, China; 3. The Centre of Iron and Steel Technology Research Institute, HBIS, Shijiazhuang 050011, Hebei, China
Abstract:Non-metallic inclusions are one of the important factors that affect the drawing performance of tire cord steels. In order to study the formation and transformation mechanism of inclusions in tire cord steel, the transformation of nonmetallic inclusions from molten steel to billet under different basicity in the industrial process of tire cord steel was observed and analyzed by ASPEX automatic scanning electron microscope. The transformation mechanism of nonmetallic inclusions was discussed using FactSage 7.0 thermodynamic calculation software. Under the condition of high basicity, the non-metallic inclusions in the molten steel are mainly CaO-SiO2-Al2O3-MnO type with a low melting point. The content of CaO and MnO in non-metallic inclusions in the billets decreases, while the content of SiO2 increases. In the heat refined by low-basicity slag, the non-metallic inclusions in molten steel are mainly SiO2-MnO-CaO type with a high melting point and the low content of Al2O3. The content of SiO2 of non-metallic inclusions in billets is higher than that in the molten steel, and the content of MnO is lower. It was indicated from the thermodynamic calculation that the transformation of non-metallic inclusions in the process of solidification and cooling of tire cord steels is caused by the phase transformation and precipitation of inclusions, the reaction between inclusions and molten steel and reaction between the dissolved oxygen and elements in the steel matrix. The transformation of the composition and morphology of inclusions from the molten steel to the billet during the industrial production of tire cord steels was well explained by the thermodynamic analysis,and provide a reference for the control of non-metallic inclusions in tire cord steels.
牛凯军, 杨文, 张立峰, 储焰平, 张洪起, 郭子强. 帘线钢凝固过程夹杂物生成热力学及工业实践[J]. 钢铁, 2020, 55(6): 61-67.
NIU Kai-jun, YANG Wen, ZHANG Li-feng, CHU Yan-ping, ZHANG Hong-qi, GUO Zi-qiang. Thermodynamics and industrial practice of formation of inclusions during solidification of tire cord steels. Iron and Steel, 2020, 55(6): 61-67.
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