Detailed details of fused zirconia corundum brick casting

The fused zirconium corundum bricks produce various defects in the production, resulting in poor quality of the products. The physical and chemical heterogeneity of zirconium corundum bricks is often the main cause of defects in products. The impervious particles in the batch and the gas inclusions that are not allowed to escape from the melt are all physically inhomogeneous. The difference in melt composition along the depth of the furnace is chemically non-uniform.

 

In fact, the common cause of defects is the destruction of the temperature regime. When the AZS brick is hardened in a closed container (if there is no subsequent melt to replenish it), shrinkage will occur due to shrinkage, which is a major drawback of fused zirconium corundum bricks. The main method for overcoming shrinkage cavities in the production of fused zirconia corundum bricks is to add a riser to the upper part of the mold to supplement the casting of the AZS bricks while cooling the bottom of the mold to allow the melt to crystallize from bottom to top. In order to ensure the formation of such crystallization, it is necessary to maintain a high temperature on the upper horizontal surface of the AZS brick and a low temperature at the bottom of the mold. Uniform directional crystallization is possible by means of bottom-up heat cleavage, so that dense AZS bricks with low porosity can be obtained.

However, to remove the shrinkage holes in the AZS bricks, the riser should have the following conditions: There should be sufficient melt in the riser that is at a higher temperature than the temperature of the AZS brick, and the riser and the riser should be correctly selected. The location is very important. The above conditions are based on the rich experience of metal casting and the production experience of 33# fused zirconium corundum brick. The riser must be calculated for each specific case. There are many basic methods for calculating risers, some of which are proposed under purely experimental conditions, and some of which are theoretically derived. The difficulty of using a large riser is that it is not easy to remove it from the cured AZS brick, and it takes a considerable amount of diamond cutter to cut it.

 

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