Control of oxide inclusions in high quality spring steel during refining process
TANG Wei1, YANG Jun1, LIU Qing2, WANG Chen2
1. Hunan Valin Xiangtan Iron and Steel Company Limited, Xiangtan 411101, Hunan, China; 2. State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
Abstract:The influence of technologies as appropriate deoxidation, slag, alloy and inclusions control was studied on the cleanliness of molten steel when lean narrow window control technics route of LF-VD-CC was used. The results show that high quality spring steel of total oxygen mass fraction less than 0.000 8%, titanium mass fraction less than 0.001 8% and acid aluminum mass fraction less than 0.002 2% can be produced, and the oxide inclusions with low melting point and deformability can be obtained effectively when the mass fraction of Al2O3 in refining top slag was controlled to not more than 5%. The oxide inclusions of melting point under 1 600 ℃ isotherm grow up ceaseless and be removed by floatation during refining process, and the remaining oxide inclusions in steel not only have low melting point and good deformability, but also have thin size, and have little influence on fatigue properties.
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