When producing fused cast AZS, the bricks are always molded in sand molds. So, the properties of the sand mold are important for the casting of AZS bricks.

The thermo-mechanical properties, average density, contraction when drying, the drying system, the moisture of the sand mold and other factors all have effect on the quality of AZS bricks.

The thermo-mechanical properties are important indicators for the quality of sand molds. Only when the sand mold meets the requirements under insulation and cooling conditions can the strength of the mold be ensured during the whole process of casting.

During casting, the sand mold is subjected to the flow pressure of the melt stream and temperature. The effective area of the sand mold to resist the pressure of the melt is reduced since the mold will lose its strength when heated to 400—500℃. Since the temperature is not even in the mold, thermal stress will be formed in the buffer of the mold.

If casting 1800℃ AZS melt into a sand or sand-quartz mold, a cured layer will be formed near the mold wall. When the thickness of the layer reaches the thickness of the template, high temperature will damage the layer of the mold.

Article Source:http://refractorybrick.over-blog.com/2016/07/the-sand-mold-for-fused-cast-azs-blocks.html