Solid-Carburizing Process of Low Carbon Steel with Carbonized Organics in Nitrogen Atmosphere

To apply carbonized organics to solid-carburizing compounds, a low carbon steel, S15C substrate, was solid-carburized at 1223 K for 18.0 ks in air with various carbonized organics in nitrogen atmosphere. Each organic changed to the black carbonized matter after carbonizing at 723 K, whereas almost organics kept a shape during carbonizing. X-ray diffraction (XRD) results show that Ca-5(PO4)(3)(OH), both KCl and KHCO3, BaCO3 and CaCO3 were identified on the surface of carbonized meat and bone meal which is organic animal products, carbonized potato, pumpkin and eggplant which are organic plant products, commercial solid-carburizing powder and milled egg shell powder, respectively. As a result of cross-sectional morphology, the martensitic structure was clearly observed on the surface region of each solid-carburized S15C sample after quenching. Hardened layer depth of most samples solid-carburized with various carbonized organics were comparable to the sample treated with commercial solid-carburizing powder, or more. These results indicate that the carbonate in solid-carburizing compounds acts as energizer for solid-carburizing process and carbonized organics and milled egg shell powder can also be used as compounds and energizer for solid-carburizing process, respectively.