“两次造渣法”冶炼不锈钢超薄带理论和工业应用

doi:10.13228/j.boyuan.issn0449-749x.20210193

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Abstract Precision calendered ultra-thin stainless steel strip (<0.3 mm) is required with sound steel cleanness and non-inclusion plasticity to obtain high comprehensive properties and surface quality while the two aspects are in contradiction. In order to solve the conflicts between steel cleanness improvement and non-inclusion plasticity,thermodynamic analysis and laboratory-scale slag-metal equilibrium experiments were carried out for achievement of high purity for stainless steel and admirable inclusion plasticity. The results show that with the slag basicity decrease, the desulfurization and deoxidation are depressed, as well as the molten steel purity, the use of high basicity slag is a necessary condition for obtaining high purity of molten steel. The inclusion composition evolves from CaO-SiO₂-Al₂O₃ based system to plasticized SiO₂-Al₂O₃-MnO based system with the decrease of slag basicity. The content of Al_s in the steel decreases, and the content of Al₂O₃ in inclusions also decreases obviously, while the plasticity becomes better. Proper MgO content addition into the slag can restrain the corrosion of lining refractory effective. It proposes a new "two step slagging strategy" based on the thermodynamic analysis, in which high basicity slag is applied in AOD to desulfurization and deoxidation, low basicity slag is employed in LF refining process to plasticized inclusions in the steel. The industrial trial results verify that the new strategy can achieve high steel cleanness and inclusion plasticity. w(T[O]) is less than 0.002 5%,w([S]) is less than 0.001 0% and inclusion is SiO₂-Al₂O₃-MnO dominated silicon-manganese aluminum-garnet inclusions with an average mass percent of Al₂O₃ lower than 20%, the plasticity is outstanding, which meets the requirement of ultra-thin stainless steel trip.

Key words： stainless steel steel purity slag basicity inclusion plasticity two step slagging strategy

Received: 08 April 2021

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	GUO Jing
	CHEN Xing-run
	HAN Shao-wei
	YAN Yan
	GUO Han-jie

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GUO Jing,CHEN Xing-run,HAN Shao-wei等. Theory and industrial applications for improvement of ultra-thin stainless steel strip purity and inclusion plasticity by development of "two step slagging strategy"[J]. Iron and Steel, 2021, 56(12): 43-51.

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http://www.chinamet.cn/Jweb_gt/EN/10.13228/j.boyuan.issn0449-749x.20210193 OR http://www.chinamet.cn/Jweb_gt/EN/Y2021/V56/I12/43

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