The lifespan of the ladle slide gate is relatively low.
Currently, in China, aluminum-zirconium-carbon is commonly used as the material for ladle slide gates. This material, with high strength, good thermal shock resistance, and excellent resistance to erosion and corrosion, is well-suited for ladle applications. However, in terms of ladle slide gate slag blocking technology, the lifespan of the slide gate is relatively short, typically stable between 10 to 14 heats. It requires replacement almost every shift, resulting in frequent mechanical replacements. This, to a certain extent, fails to meet the demands of the fast-paced steelmaking process in the converter, and also increases the labor intensity for workers.
Export lifespan needs further improvement.
The export lifespan is one of the crucial indicators for ladle slide gate slag blocking technology. Due to constant exposure to high-temperature molten steel and highly oxidizing furnace slag, combined with rapid cooling and heating effects, the export is susceptible to damage. Its lifespan directly affects the converter smelting cycle, steel production rate, slag blocking effectiveness, and consequently, the quality of the steel. The integrity of the export directly controls the amount of slag drained from the converter, which directly affects alloy recovery rate and the subsequent refining processes (LF, RH, etc.).
Currently, the lifespan can be stabilized between 90 to 110 heats, but it is challenging to surpass this bottleneck and achieve a higher lifespan. The core issue lies in the bonding between the steel outlet and the inner nozzle brick, which relies on a flat or nested contact adhered by refractory mortar. The contact surface is a planar interface, making it more prone to air infiltration. Oxidation, loosening, and peeling of the contact surface due to multiple replacements, especially in the contact part of the steel outlet and inner nozzle (end C brick), are more pronounced. As it needs to be used in coordination with multiple sets of inner nozzle bricks, the impact of oxidation and loosening on the contact surface is even more significant, and the usage time of the steel outlet end C brick has become the key factor in determining whether the steel outlet can have a long lifespan.
