The main feature of special-shaped refractory bricks is high early strength, with a compressive strength of over 30MPa at room temperature after 3-7 days. The disadvantage is poor volume stability at medium temperature, resulting in a decrease in strength by about 40%. Therefore, it is required that the compressive strength at room temperature must meet the design and national standard requirements. The main factor causing the decrease in thermal strength is that when the low calcium high aluminum cement of the irregular refractory brick reaches a certain temperature (around 350 ℃) during the heating process of the furnace, the hydrates begin to dehydrate and transform, resulting in a decrease in the structure, density, and strength of the cement stone, and a change in the volume of the castable. At this time, the strength of the castable body drops to a low point and then tends to stabilize.
As the heating temperature rises to 1100 ℃, the cement stone gradually sinter, and the crystal structure of the shaped refractory brick begins to transform into mullite crystals. As the temperature continues to rise, the mullite crystals continue to grow, and the matrix glass phase in the casting material is in a liquid state, forming a high-temperature ceramic sintered state with significantly improved strength. At around 1300 ℃, the strength of the special-shaped refractory brick can reach over 60MPa, which is also a significant characteristic of the high-temperature state of special-shaped refractory bricks.
Contact me:
Email:wp@cnjingganrefractory.com/sdwenping@163.com
TEL: 86-0533-4188518 / FAX: 86-0533-4188518
Rose:+86-13275332819(wechat/whatsapp number)
