Effect of cleaning parameters on the molten pool shape and molten slag dynamics in the corner scarfing process of the casting slab

Abstract

In the steel industry, improving the hot charging and heat delivery ratio in the continuous casting of slabs and thick slabs can effectively reduce carbon emissions, lower energy consumption, and improve production efficiency. However, this puts very strict requirements on the surface quality of continuous-casting slab. Flame scarfing (or cleaning) technology is currently an important process in the metallurgy field, which can effectively remove impurities and crack defects on the surface and corners of continuous casting slab to ensure the quality and performance of the final product. Under the action of cleaning flame and iron oxide reaction heat, a cleaning molten pool is formed in the corner of the casting slab, and the shape and depth of the molten pool have an important influence on the cleaning effect. A three-dimensional mathematical model is developed to study the effect of slab cleaning speed and oxygen flow rate on the shape of the molten pool in the corners for the corner flame cleaning process. Simultaneously, a two-phase flow volume of fluid (VOF) model for gas-slag interactions is employed to examine the motion behavior of the molten slag. The results showed that when the operating conditions changed, the cleaning speed increased by 1 m/min, the length of the wide and narrow sides decreased by approximately 9.2 mm, and the depth of the corner pool decreased by approximately 5.3 mm. Moreover, a slag-blocking device was designed to mitigate the issue of slag splashing effectively based on the numerical simulation results compared with and without the slag-blocking device. These study works provide beneficial theoretical support and practical guidance for refining and optimizing flame-cleaning techniques.