A study of comparison different Al2O3-ZrO2-C slide gate plates for the casting Al killed steel

Abstract

Continuous casting refractories are the most important materials that provide critical flow control components in steel making process. Ladle slide plates, named in this group, are subjected to sudden thermal shock, physical erosion of molten hot metal and slag. Therefore, the slide gate plate must have good resistance to both thermal shock and corrosion [1]. Generally, alumina based plates are used for Al-killed steel casting processing, however these plates are subjected to huge corrosion during alloy casting which contains higher amount of Mn, Cr or Ca (Ca >15-30ppm) [2]. In order to overcome this major concern ZrO₂ additives have been started to be used. Its well-known that, addition of Ca is the best way to avoid Al clogging problems in Al killed steels.  However, the Ca content in Al₂O₃-ZrO₂-C (AZC) slide plates results in increased corrosion. Hence, it is necessary to determine the most suitable ZrO₂ percentage content in the sliding plate for the continuity of the process and the reliability of continuous casting.

The present paper deals with corrosion and diameter expansion comparison results of three different content of ZrO2 slide plates that used in 250-ton ladles in medium carbon Al-killed steel production. In the comparison studies, LF (Ladle Furnace) output analyzes, temperature of liquid steel (T_{s-liq -s}), casting speeds, total casting times values and operating factors such as full open or semi open operation of the mechanism were taken into considered.

The test results provide information about which zircon ratio is suitable for a reliable casting process and the maximum number of castings that can be achieved.