The influence of water glass on the properties of microwave cured molding sands

This work presents results of research on the influence of microwave heating time on the process of hardening of microwave cured 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, while supplementing and reinforcing influence of water glass addition on these parameters, known from practice as well as literature, has been found. A beneficial influence of hardening (drying) process has been observed in case of all available on the market kinds of this binding agent (including the most frequently used in foundry 145 and 149 kinds). It has been proved, that microwave heating guarantees obtaining very good, in comparison to traditional carbon dioxide hardening process, strength and resistance properties as well as technological characteristics of molding sand with only 1.0 up to 1.5% content of water glass. Microwave curing of water glass moldings sands guarantees, apart from a significant process time reduction, a full stabilization of their properties as well as considerable lower energy consumption and allows for amount reduction of the used binding agent and, as a result, improvement of knock-out properties of the sands. Microwave heating of water glass molding sands, through suitable process parameter selection, results in the possibility of forecasting and control of their properties.