Liquid-phase sintering refers to sintering produced by liquid phase. The liquid phase may be formed by the reaction of alkaline oxides such as Fe2O3, Na2O, TiO2, and K2O with Al2O3 and SiO2, resulting in a decrease in the high-temperature strength of the shell and cooling of the liquid phase. The particles are firmly connected to increase their residual strength. At 1200-1500°C, secondary morpholinization occurs in the shell, and alkaline oxides form liquid phases with Al2O3 and SiO2, resulting in increased shell-like residual strength and possible high-temperature softening. The recrystallized sinters above 1500°C have been in the softening stage, the residual strength has increased significantly, and the shelling has deteriorated. Fe, Mg, Na, Ca, K and other elements react with Al2O3 and SiO2 to form low-melting substances during high-temperature roasting, which results in changes in the surface morphology of the shell and may cause high-temperature softening of the shell. In order to ensure the surface quality of the shell and good shelling, reduce the possibility of high temperature softening during the casting process, we must strictly control the content of impurities in the shell. Clearly, the temperature has an important influence on the residual strength of the silica sol shell. The variation of the residual strength of the shell under different calcination temperatures: when the calcination temperature is between 900 and 1200 °C, the residual strength of the shell remains basically unchanged; when the temperature is between 1200 and 1500 °C, the residual strength of the shell gradually increases with the increase of the temperature; At 1500 °C, the residual strength of the shell increased significantly. Therefore, controlling the roasting temperature of a good shell in precision casting can effectively improve the shelling performance of the silica sol shell. In the process of precision casting, the factors influencing the shelling performance of silica sol shells are relatively complex and mutually restrictive. The actual production should be based on the structural characteristics of each casting and the requirements for shelling, selection of shell raw materials, the development of a reasonable process plan, to ensure that the shell has sufficient high temperature strength, to reduce the residual strength, improve the shelling performance purpose. Round Bathtub Round Bathtub Guangzhou Aijingsi Sanitary Products Co.,Ltd , https://www.comoxvalleyhottubs.com
Temperature has an important influence on the residual strength of silica sol shells