Four casting methods of fused cast AZS bricks

The fused zirconium corundum brick ingot will form chemical-phase composition segregation along the cross section due to the effect of temperature gradient during the condensation process.

 The higher the ZrO2 content, the larger the ingot size, the worse the segregation degree.
The ingot is generally divided into three zones: the surface rapid cooling zone (small and uniform crystals), the middle dense zone (high concentration of ZrO2, the crystal growth) and the shrinkage cavity zone (cavity).
The first two zones are the most resistant to erosion.
The condensation of the melt in the sand mold will cause a volume shrinkage of 12% to 15%, forming shrinkage cavities.
According to the size of the shrinkage cavity and the treatment method, there are four casting methods.

① Ordinary casting method (abbreviated as PT) is cast with ordinary risers.
The first solidified part has fine crystals, and the latter solidified part has coarse crystals.
There are large shrinkage holes, and the position of the shrinkage holes is basically the same as that of the casting holes on the brick surface.
The bulk density is around 3.3g/cm3.
②The inclined casting method (abbreviated as QX) places the mold at a certain angle, and the riser is placed on the upper end of the mold, so that the shrinkage cavity is condensed at one end of the product, and the position of the shrinkage cavity is close to the bottom of the brick.
Most of the molds are dense, especially in the lower half of the bevel.
This method works for long bricks.
③No shrinkage casting method (abbreviated WS) casting sand with additional dimensions.
Concentrate the shrinkage at the top.
Cut off after annealing.
The rest of the used part is uniform in composition and dense in organization.
④ Dense casting method (abbreviated as MS) Dense casting method is also known as strengthening casting method or multiple supplementary pouring method.
In the first casting, shrinkage cavities are generated, and after a certain period of time, a riser is replaced, and then supplementary pouring is performed.
This can greatly reduce the shrinkage cavity volume and improve the full casting rate of the casting.
The average bulk density of fused zirconium corundum bricks containing 33% ZrO2 can reach about 3.6g/cm3.