Abstract
Precipitation behavior during normalizing heat treatment has been investigated on a 9Cr-1Mo-V-Nb steel. Heterogeneously distributed spherical MX (M=Nb, V, Cr and X=C, N) carbonitride particles and platelet M3C (M=Fe, Cr) carbide were observed in the as normalized condition. Number of the precipitates decreased with increasing normalizing temperature and no precipitates was observed after normalizing at 1250°C. Although the size of M3C was almost constant independent of normalizing temperature, that of MX increased with increase in normalizing temperature up to 1200°C. For MX carbonitride, not only size, but also composition of metallic elements was influenced by normalizing temperature. Since equilibrium composition of MX carbonitride depends on temperature, MX particle with non-equilibrium composition dissolves and precipitation of it takes place with its equilibrium composition at the normalizing temperature. A phase field diagram of NbX-VX quasi binary system in a 9Cr-1Mo-V-Nb steel was experimentally determined. It has been supposed that precipitation of M3C takes place during cooling from normalizing temperature in the surrounding area of MX particles where the concentration of niobium and vanadium in matrix is poor.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
