Investigation of Thickness Effects on Cooling Rate and Hardness of Gray Cast Iron in Metal and Sand Molds

This study investigates the influence of casting thickness on the cooling rate of gray cast iron using metal molds and compares it to the cooling rate achieved with traditional sand molds. Sand molds represent the oldest and most widely used method in metal casting, while metal molds are a relatively newer application for gray cast iron. The cooling rates during solidification were monitored using thermocouples connected to a data logger. The smelting of gray cast iron was performed in an induction furnace, with some samples inoculated using FeSi and FeMn additions, while others were cast without inoculation. This study analyzed the chemical composition, microstructure, hardness, and surface morphology of gray cast iron through SEM-EDS for both inoculated and non-inoculated samples. The results indicate that FeSi and FeMn inoculation enhanced the carbon content of the cast iron. Additionally, while the differences in cooling rate due to the casting thickness in permanent metal molds were not substantial, a distinct pattern emerged. The mid-thickness regions exhibited the highest cooling rates, which influenced the hardness distribution across the castings. This research highlights the nuanced effect of the mold type and casting thickness on the cooling dynamics and mechanical properties of gray cast iron.