Abstract
Isothermal oxidation of plasma-nitrided tool steel at 750°C, typical of steel thixoforming process, was investigated. A multi-layered oxide forms on the surface of plasma nitrided X32CrMoV33 hot work tool steel when held at 750°C in an air furnace for 6 hours. The hematite layer at the surface is replaced by magnetite in the middle. The innermost layer is an iron –chromium spinel with approximately 4 at% Cr. These features are typical of oxidised low-Cr steels and suggest that nitriding does not affect the response to thermal exposure of hot work tool steels at elevated temperatures. It is thus concluded that hot-work tool steels are inadequate for tooling in the steel thixoforming process even when plasma-nitrided. The substrate tool material must contain higher levels of Cr to assure a slowly growing, adherent Cr2O3 layer to reduce the overall oxidation rate.
Sign-in/Register to access full text options 
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.
