What are the reasons for cracks in fused azs brick?

Fused azs brick is a high-quality refractory material, mainly used in high-temperature equipment in forni per vetro, metallurgical furnaces, and petrochemical industries. It has the advantages of good high-temperature strength, strong resistance to chemical erosion, good wear resistance, and excellent thermal shock stability. Tuttavia, in practical applications, fused zirconium corundum bricks occasionally crack, which not only affects the service life of the brick body but may also cause equipment failure and damage. This article will analyze in detail the main reasons for cracks in fused zirconium corundum bricks.

The main reason for cracks in fused azs brick

Raw material composition and formula ‌

The raw material composition and formula of fused bricks have an important influence on their performance. If the raw materials contain too many impurities or the proportion of ingredients is improper, the brick body may shrink unevenly during the cooling process, thus causing network cracks. Perciò, optimizing the raw material formula is the key to reducing the occurrence of cracks ‌

Production process control ‌

The control of the production process is also an important factor affecting the quality of fused bricks. In the production links such as smelting, casting, and cooling, any improper operation may cause stress inside the brick body, and then form cracks in the subsequent process. Especially in the cooling stage, too fast or too slow cooling speed may cause the brick body to crack .

Temperature change and thermal stress ‌

Fused bricks will experience drastic temperature changes during the production process. During the cooling process from high-temperature molten state to room temperature, complex thermal stress will be generated inside the brick body. If the thermal stress is not effectively released, a network crack will be formed on the surface or inside the brick body ‌

Stress distribution and release ‌

In addition to thermal stress, mechanical stress is also an important cause of network cracks. In the production, transportation and use of fused bricks, the action of various mechanical forces will cause stress concentration inside the brick body. When these stresses exceed the bearing limit of the brick, they will be released in the form of cracks.

Crystal transformation

During the cooling and crystallization process, the melt of the fused zircon corundum brick will undergo a large volume change due to crystal transformation, especially when the high-temperature cubic crystal system is transformed into the monoclinic zircon below 1008℃, it will be accompanied by a large volume expansion, which may also lead to the formation of network cracks.