[T12] Ferrous Materials

[14F-T12-04] Effect of Vacuum Carburising on Tensile Properties of Fe-Cr Sintered Steel

T. Yamada¹, M. Aramaki¹, T. Ohnishi³, H. Sakuta², H. Kabasawa³, M. Aramaki¹, *Y. Ozaki¹ (1.Kyushu University, Japan, 2.Nihon Parkerizing Co., Ltd., Japan, 3.Nihon Techno Co., Ltd., Japan)

キーワード：Vacuum Carburization, Fe-Cr sintered steel, Tensile properties, Acetylene gas

When considering the conservation of rare metal resources, the use of Cr as an alloying element is important in the alloy design of iron-based sintered materials because of its high quenching multiple and the ability to increase the strength of materials with the addition of small amounts of Cr. However, Cr, which is also a readily oxidizable element, is preferentially oxidized by the presence of H₂O and CO₂ in the atmosphere in the conventional carburizing process using hydrocarbon-modified gas. Oxidation of Cr during carburizing is a problem to be solved because it leads to variation in the mechanical strength of sintered and carburized materials. Therefore, in this study, we applied vacuum carburization using acetylene gas, which can suppress Cr oxidation and further reduce the environmental load without CO₂ emissions, to Fe-Cr sintered steels. In this paper, will be reported the tensile properties of the vacuum-carburized materials.