PENGARUH PROSES SHAW DAN UNICAST TERHADAP SIFAT FISIS DAN MEKANIS CETAKAN COR PASIR KROMIT

Abstract

Steel casting has been done using sand molds, both river sand and silica sand, tends to experience casting defects, especially surface defects. One way to overcome surface defects is to use sand that has a higher melting point, including chromite sand and zircon sand. Chromite sand has a higher price, so it is often mixed into silica sand, but this mixing can cause clumping when exposed to molten metal at high temperatures (e.g. steel). One solution proposed in several literature is using ceramic molds. Ceramic molds are molds made of ceramics or minerals, in this case, sand that has been sintered to become ceramics. For this reason, it is necessary to test the ability of chromite sand as a raw material for this ceramic mold. There are two ceramic sintering processes, namely the Shaw process and the Unicast process, where the Shaw process requires higher production costs because the sintering time is longer. In this study, the Shaw process showed better ability than the Unicast process in producing chromite sand ceramic molds, with an optimum sintering temperature of 1050°C. The Fenotec 810 resin produced by PT. Foseco Indonesia is a binder that has varying drying time characteristics, so it can be adjusted according to needs in forming ceramic molds.