Use of rice husk as hot tipping on steel casting parts

Abstract

The use of feeding aids in the foundry process has become widespread globally recent decades, leading to increased efficiency. This article examines the characterization of rice husks, their ashes, and their positive impact as hot topping on the efficiency of open risers in casting cylindrical parts made of AISI 1045 steel. The rice husks were analyzed through X-Ray Diffraction test, Thermal-Gravimetric Analysis, and Differential Thermal-Gravimetric Analysis, while the ashes were characterized using X-Ray Diffraction. The analyzed rice husks were found to contain cellulose and low crystallinity silicon, whereas the ashes primarily consisted of cristobalite and tridymite. It was observed that the thermal decomposition of rice husks occurs in three stages, with approximately 81% of the mass lost during their combustion as hot topping on liquid steel. The location of cavities contraction in the risers of casting parts was made through longitudinal cut of the part-riser system. The increase in the rice husks topping layer thickness positively influences the concentration of these cavities on the upper surface and enhances the feeder's efficiency.