Analysis on evolution law of inclusions in H08A wire steel
LIU Jun1, SONG Zhao-qi2, LIU Jie2, YANG Shu-feng2, LI Jing-she2
1. Nanjing Iron and Steel Co., Ltd., Nanjing 210035, Jiangsu, China; 2. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
Abstract：In order to improve the drawing and welding performance of H08A welding wire steel, the whole process of this steel was sampled and analyzed, the morphology of the inclusions were observed by scanning electron microscope, the number density was counted, and the composition change and distribution of inclusions were analyzed by the inclusion automatic analysis system. The low melting point area distribution of inclusions was verified using FactSage thermodynamics software. The results show that the total oxygen content in steel can indirectly reflect the number density of inclusions. Without LF refining and tundish protection pouring, it is difficult for the total oxygen in cast slab to reach the required 0.005%. The type of inclusions is mainly the composite inclusions of silico-manganese-aluminum oxide. After deoxidation and alloying, composition of inclusions tends to be stable. Most of large-size inclusions are MnO-SiO2-Al2O3, with a maximum size of 70 μm. The calcium yield is not high, and no typical calcium oxide inclusions are found in the inclusions. The inclusions are mainly spherical, and the total amount of large-size inclusions is large. In the tundish and cast slab, large-size inclusions below 80 μm account for a relatively small proportion, and large-size inclusions above 80 μm account for about 87.6%-87.9%.
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LIU Jun, SONG Zhao-qi, LIU Jie, YANG Shu-feng, LI Jing-she. Analysis on evolution law of inclusions in H08A wire steel[J]. China Metallurgy, 2021, 31(3): 44-49.
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2021, Vol. 31 
