Abstract: As a secondary refining apparatus, the ladle furnace(LF) plays a pivotal role in contemporary steelmaking processes. The performance of LF lining refractory materials  is crucial for controlling the composition of molten steel, enhancing production efficiency, and ensuring cost-effectiveness. Magnesia-carbon bricks are frequently utilized as lining materials for their superior high-temperature strength and excellent resistance to erosion. However, under the process model of adding scrap steel to molten steel in LF, the introduction of scrap leads to fluctuations in slag composition, which periodically reduces the slag basicity and consequently accelerates the erosion and degradation of magnesia-carbon bricks. This study focuses on the magnesiacarbon bricks used in the LF at  a steel plant, investigating the impact mechanism of changes in slag basicity on the erosion behavior of these bricks. Research findings indicate that at high basicity (R=4.88), erosion primarily manifests as infiltration; whereas at low basicity (R=1.57), dissolution becomes more prominent, with the rate of dissolution increasing and the thickness of the eroded layer growing as basicity decreases. Furthermore, the analysis of post-service magnesia-carbon bricks from the field corroborates the experimental outcomes, providing theoretical insights for extending the service life of magnesia-carbon bricks.

Key words: ladle furnace, slag basicity, magnesia-carbon refractories, erosion behavior