Carbide Evolution in High-Carbon Martensitic Stainless Cutlery Steels during Austenitizing

摘要

The carbide phase is critical in high-carbon martensitic stainless steels (HCMSS) used for cutlery. In this study, carbide evolution during the austenitizing of different HCMSS (5Cr15MoV, 7Cr17MoV, 9Cr14MoV, and 9Cr18MoV) and its effect on the microstructure and mechanical properties are investigated. The statistical analysis of carbides suggests that the dissolution of small-sized secondary carbides (< 0.5 mu m) improves the hardness. The improvement in toughness is related to the increase in the volume fraction of the retained austenite determined by the dissolution of the larger secondary carbides (> 0.5 mu m). Due to the influence of the elemental diffusion distance, the interfacial energy, and directional dissolution, smallsized carbides are more soluble than large-size carbides, which can be determined by the change of the ratio of Cr/Fe (wt.%) of carbides.