The influence of microwave heating and water glass kind on the properties of molding sands

This work presents results of research on the influence of microwave heating time on the process of hardening of water glass molding sands. Essential influence of this drying process on basic properties such as: compression, bending and tensile strength as well as permeability and wear resistance, has been found. It has been proved, that all the investigated sorts of sodium water glass could be used as binding material of molding sands intended for curing with the microwave process heating. It has been found, while analyzing the results of property studies of microwave heated molding sands with 2.5% addition of water glass, that all available on the market kinds of this binding agent (including the most frequently used in foundry 145 and 149 kinds) after microwave heating guarantee very good compression, bending and tensile strength as well as permeability and wear resistance. Moreover, it has been determined that the optimal curing power of molding sands containing various kinds of water glass is 560 W. All values exceeding this result in stabilization of basic properties of molding sands. The use of microwave curing of water glass molding sands results in a significant decrease of hardening a process time, full stabilization of molding sands as well as much lower energy consumption.