Automatic Vapour Sorption Analysis as New Methodology for Assessing Moisture Content of Water Based Foundry Coating and Furan Sands

Abstract

Gas generated during the casting process can cause defects that increase the cost of the components and possibly lead to scrapping the parts. Gases are produced during evaporation of water and by decomposition of organic materials present in the foundry coating and in the moulding sand. This study investigates how equilibrium water content varies in foundry coating and in different furan based binding systems with the objective to determine what variables are critical for material moisture process control. The influence of relative humidity, temperature, dust levels and binder type are investigated. Results show that highest effects are given by relative humidity and binder type. They can cause moisture level variations from 0.1% to about 0.8%. Temperature and dust levels play a minor role. Hysteresis effects between sorption and desorption curves are limited. Finally, the sorption curves are fitted with 3rd order polynomial equations.