EFFECT OF SULPHUR ON WETTABILITY OF LIQUID FE-0.45%C WITH ALUMINA

Non-metallic inclusions, particularly alumina (Al2O3), pose significant challenges in steelmaking. Their behaviour in molten steel is largely governed by wettability. This study investigates the effect of sulphur, a surface-active element, on the wettability between liquid Fe-0.45%C and alumina substrates, to improve the understanding of alumina non-metallic inclusion formation in medium carbon steel. Experiments were conducted using the sessile drop method in a high-temperature melting microscope. Three Fe-0.45%C samples with varying sulphur contents (0.0020, 0.0120, and 0.0340 w/%) were placed on polished single-crystal alumina substrates and heated to 1600 °C in a purified argon atmosphere. Results show that increasing sulphur content in the Fe-0.45%C melt decreases the contact angle with alumina substrates from 106.5° (0.0020 w/% S) to 102.0° (0.0340 w/% S). Furthermore, sulphur addition increases the influence of temperature leading to a clearer trend of decreasing contact angle values as temperature rises. This implies an increased risk of solid alumina non-metallic inclusion formation if the sulphur content is elevated.