Effect of inclusion collision, refractory erosion, reoxidation and slag entrainment on large size inclusions in low-carbon aluminum-killed steel

The production of high-performance low-carbon aluminum-killed steel critically depends on the control of non-metallic inclusions. In particular, large-size inclusions can induce severe surface defects in steel products. Although prior studies have identified various potential sources of such inclusions, these investigations have typically focused on individual factors in isolation. Few studies have conducted comparative analyses of multiple factors within a unified framework. This study performs a systematic analysis of industrial steel samples, followed by laboratory-based thermal simulation experiments. Four distinct experimental schemes were designed to simulate the effects of inclusion collision, refractory erosion, slag entrainment, and reoxidation on the formation of large-size inclusions in low-carbon aluminum-killed steel. The results indicate that reoxidation exerts the most significant influence, contributing to a 117.9% variation in large inclusion characteristics. Slag entrainment is the second most influential factor, accounting for 105.3% variation, with tundish covering slag and mold powder exhibiting greater impact than ladle slag. Refractory erosion and inclusion collision show comparable but relatively modest contributions, with variation rates of 50.4% and 44.5%, respectively.