| One mechanism that many surface hardening process applied to the spindled-shaped component is carburizing process. The carburizing is a process of diffusion of carbon in carbon steel surface, thereby increasing the carbon content in the surface. Carburizing process certainly requires a source of carbon, which can be solid, gas and liquid. According to a study turns green mussel shells containing CaCO3 is quite high, about 66.70%. Thus, the carbon contained in the shells potential to be used as a source of carbon in the surface hardening process. Utilization of waste shells can be one of the efforts to make green environment. In this research, the potential of the green mussel shell waste as a source of carbon in the carburizing process about to be answered through a heat treatment process. Optical metallographic and hardness tests conducted in this research were undertaken to investigate the consistency of the relationship between microstructure and hardness number to calculate the depth of hardening that occurs. Increased surface hardness ST 37 steel occurs very significant at the time of the addition of the energizer by 40-50% with carburizing time for eight hours. The result of this research, powder shells or have not yet potentially effective when used as an alternative source of carbon in the pack carburizing process on an industrial scale. The time needed to carbon diffuses from powder shells to the surface of the shaft very long, it means requires more energy. If the green mussel shell powder is used as a carbon source in the industry need to think about costs. |