Characteristics of SEN clogging and adhesive behavior of oxide inclusion during continuous casting of Ti-stabilized ultra-pure ferritic stainless steels
Xue-feng Bai1, Yan-hui Sun1, Hui-bin Wu1
1 Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China
Characteristics of SEN clogging and adhesive behavior of oxide inclusion during continuous casting of Ti-stabilized ultra-pure ferritic stainless steels
Xue-feng Bai1, Yan-hui Sun1, Hui-bin Wu1
1 Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China
摘要 Submerged entry nozzle (SEN) clogging during continuous casting of Ti-stabilized ultra-pure ferritic stainless (Ti-UPFS) steels was systematically investigated via cross-sectional analysis and acid dissolution treatment. The SEN deposit profile was characterized as occurring in three major layers: (1) an eroded refractory layer; (2) an initial adhesive layer comprised an Al2O3–ZrO2 composite sub-layer and a dense Al2O3-based deposit sub-layer; and (3) a porous multiphase deposit layer mainly consisting of MgO∙Al2O3, CaO–Al2O3, and CaO–TiOx. The MgO∙Al2O3-rich inclusions did not adhere directly to the eroded refractory but were entrapped during the deposit growth. Results of inclusion characterization in the tundish revealed that the MgO∙Al2O3-rich particles present in the tundish served as the primary source of clogging deposits. Furthermore, a novel cavity-induced adhesion model by circular approximation was established to explain the effects of complex inclusion characteristics and refractory material type on adhesion force. A high number of small MgO∙Al2O3 inclusions were expected to accelerate the buildup of clogging deposits. Improving the modification of MgO∙Al2O3-rich inclusions in the size range of 2–4 μm by Ca treatment was crucial to minimizing the risk of SEN clogging during the continuous casting of Ti-UPFS steels.
Abstract:Submerged entry nozzle (SEN) clogging during continuous casting of Ti-stabilized ultra-pure ferritic stainless (Ti-UPFS) steels was systematically investigated via cross-sectional analysis and acid dissolution treatment. The SEN deposit profile was characterized as occurring in three major layers: (1) an eroded refractory layer; (2) an initial adhesive layer comprised an Al2O3–ZrO2 composite sub-layer and a dense Al2O3-based deposit sub-layer; and (3) a porous multiphase deposit layer mainly consisting of MgO∙Al2O3, CaO–Al2O3, and CaO–TiOx. The MgO∙Al2O3-rich inclusions did not adhere directly to the eroded refractory but were entrapped during the deposit growth. Results of inclusion characterization in the tundish revealed that the MgO∙Al2O3-rich particles present in the tundish served as the primary source of clogging deposits. Furthermore, a novel cavity-induced adhesion model by circular approximation was established to explain the effects of complex inclusion characteristics and refractory material type on adhesion force. A high number of small MgO∙Al2O3 inclusions were expected to accelerate the buildup of clogging deposits. Improving the modification of MgO∙Al2O3-rich inclusions in the size range of 2–4 μm by Ca treatment was crucial to minimizing the risk of SEN clogging during the continuous casting of Ti-UPFS steels.
Xue-feng Bai,Yan-hui Sun,Hui-bin Wu. Characteristics of SEN clogging and adhesive behavior of oxide inclusion during continuous casting of Ti-stabilized ultra-pure ferritic stainless steels[J]. Journal of Iron and Steel Research International, 2023, 30(10): 1939-1951.