Iyer R, Ramrattan S, Lannutti J, Li W

Abstract: Chemically bonded sand cores and molds are an important part of metal casting technology and their behavior in contact with molten metal is of great interest. The various test methods currently employed to measure heat-induced thermo-mechanical changes cannot satisfactorily explain the influence of binder thermo-chemistry on dimensional changes. The new thermal distortion test uses a disc specimen that remains intact after thermal exposure offers a method to study the changes brought about by the thermo-chemical reactions of the binder. In the present work, specimens based on conventional shell, phenolic urethane and an alkaline phenolic-ester type binder system were studied and the changes observed are correlated to the curing and decomposing characteristics of the binders. In addition, X-ray Computed Tomography was used to characterize the uniformity of these composites as it related to the forming conditions.

Keywords: Chemically bonded sand, Thermo-mechanical properties