Effect of Niobium on the Secondary Precipitates and Tempering Resistance of Spray-Formed M3:2 High-Speed Steel

Journal Article · Fri Feb 15 04:00:00 EST 2019 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-019-3883-3· OSTI ID:22970935

Wang, Hebin ^[1]; Hou, Longgang ^[2]; Li, Yabin; Ou, Ping; Shen, Li; Wen, Xinger ^[1]; Cui, Hua; Zhang, Jishan ^[2]

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1. Jiangxi University of Science and Technology, School of Materials Science and Engineering (China)
2. University of Science and Technology Beijing, State Key Laboratory for Advanced Metals and Materials (China)

The precipitation of secondary carbides in spray-formed M3:2 high-speed steels with or without 2% niobium (Nb) addition during overtempering at 600 °C was characterized, and the carbides were identified in detail using transmission electron microscopy. Strengthening in the peak-hardened state is due to coherent precipitates of types MC and M{sub 2}C. During overtempering, the hardness of M3:2 steel greatly decreases due to M{sub 2}C coarsening with the precipitation of M{sub 3}C carbide, whereas the very fine and dense nature of the M{sub 2}C precipitates is responsible for the remarkable long-time strength exhibited by the Nb-containing steel. The MC precipitates, however, are fairly stable. The addition of Nb results in substantial dissolution of Mo and Cr into the matrix prior to tempering, which refines the secondary M{sub 2}C precipitate dispersion and delays overaging reactions; therefore, superior tempering resistance can be obtained.

• OSTI ID: 22970935
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 2 Vol. 28; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBIDES
NIOBIUM
PRECIPITATION
STEELS
TEMPERING
TRANSMISSION ELECTRON MICROSCOPY