Effect of slag composition on steel cleanliness in interstitial-free steel

• 作 者: Rui Wang Yan-ping Bao Yi-hong Li Tai-quan Li Di Chen
• 机 构: State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,School of M
• 出 处: Journal of Iron and Steel Research(International)
• 发表日期: 2017年06期
• 关键词: IF steel Ladle slag Reoxidation Inclusion Holding process

Ladle slag affects steel cleanliness at the end of the Ruhrstahl-Hereaeus(RH)and holding process.The relationship between composition of ladle slag,total oxygen(TO)and inclusions was investigated using X-ray fluorescence(XRF),infrared absorption,and SEM+EDS methods.The results indicate that TO in steel at the end of RH increases linearly with increasing FeO content in slag.TO is lower when wCaO/wAlO(C/A)=1.5-2.0than4under23 that of C/A=1.0-1. an approximate content of FeO.During the holding process,irregular Al_2O_3 inclusions are newly generated due to slag reoxidation.Additionally,Al_2O_3-Ti_xO inclusions are newly generated in the steel when the content of FeO is higher.By combining experimental and thermodynamic calculation results,it is determined that the slag has a good melting property within the zone of C/A=1.2-1.8and adsorption capacity of Al_2O_3 when the content of SiO_2 in slag is controlled at 4%-6%.The increase in the C/A ratio and the decrease of FeO content in slag can slow down the reoxidation rate.

Ladle slag affects cleanliness at the end of the Ruhrstahl-Hereaeus (RH) and holding process. The relationship between composition of ladle slag, total oxygen (TO) and inclusions was investigated using X-ray fluorescence (XRF) SEM + EDS methods. The results indicate that TO in steel at the end of RH increases linearly with increasing FeO content in slag. TO is lower when wCaO / wAlO (C / A) = 1.5-2.0 than4under23 that of C / A = 1.0 An approximate content of FeO.During the holding process, irregular Al 2 O 3 inclusions are newly generated due to slag reoxidation. Additionally, Al 2 O 3 -Ti xO inclusions are newly generated in the steel when the content of FeO is higher.By combining experimental and thermodynamic Calculation results, it is determined that the slag has a good melting property within the zone of C / A = 1.2-1.8 and adsorption capacity of Al 2 O 3 when the content of SiO 2 in slag is controlled at 4% -6%. The increase in the C / A ratio and the decrease of FeO content in slag can slow down the reoxidation rate.