Formation mechanism of submerged entry nozzle #br# clogging layer structure of 40Cr steel
JI Sha1，LUO Yan1，ZHANG Guofeng2，JIA Wenjun2，REN Ying1，ZHANG Lifeng1
(1. School of Metallurgy and Ecological Engineering， University of Science and Technology Beijing，
Beijing 100083, China；
2. Technology Center， Lingyuan Iron and Steel Co.， Ltd.， Lingyuan 122500， Liaoning， China)
Abstract：In order to clarify the formation mechanism of the layered structure of 40Cr steel submerged entry nozzle clogging under the conditions of BOF→LF refining→continuous casting process. The morphology and layered structure of 40Cr steel nozzles were analyzed comprehensively by scanning electron microscopy，cathodoluminescence and FactSage7.1 thermodynamics software. The research shows that the submerged entry nozzle clogging from the nozzle side to the molten steel side is divided into a nozzle decarburization layer，a condensation steel layer，an inclusion accumulation layer，a condensation steel layer and a surface loose layer. The layered deposition of Al2O3，Al2O3CaO(SiO2) and Al2O3MgO spinel in the inner wall of 40Cr steel in continuous casting process is revealed. Combined with the production process，the formation mechanism of the doublecondensed steel layer was studied，and the formation mechanism of the clogging was explained by thermodynamic calculation.
