Nature of the high hardness of P/M high-speed steels
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High hardness of P/M high-speed steels is observed with a large amount of retained austenite −50–60%.
The largest amount of retained austenite (50–60%) is formed with cooling at rates of 104–105 deg/sec.
The variations of the amount of retained austenite and distortion of the lattice with the cooling rate are similar, which indicates supersaturation of austenite with carbon and alloying elements.
The reasons for the high hardness of the particles with a large amount of retained austenite are the high supersaturation of austenite (and thus martensite) with carbon and alloying elements, the partial decomposition of austenite during cooling with precipitation of highly dispersed carbides, refining of the structural components, including eutectic carbides, and the change in the quantitative ratio of the carbides, the principal carbide being MC.
KeywordsPrecipitation Carbide Austenite Martensite Cool Rate
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- 1.Yu. A. Geller et al., "Structure and properties of high-speed steels in relation to cooling rate in the temperature range of primary crystallization," Metalloved. Term. Obrab. Met., No. 6, 44 (1979).Google Scholar
- 2.I. S. Miroshnichenko et al., "Effect of cooling rate and subsequent annealing on the structure of R6M5K5 powder," in: Production, Properties, and Applications of Atomized Metallic Powders [in Russian], IPM Akad. Nauk Ukr. SSR, Kiev (1976), p. 66.Google Scholar
- 3.A. K. Petrov et al., "Crystallization of metallic powders produced by atomization of the liquid phase," Poroshk. Metall., No. 1, 16 (1973).Google Scholar
- 4.A. N. Popandopulo, "Phase composition and structure of atomized powders of high-vanadium W−Mo steel," Poroshk. Metall., No. 12, 5 (1976).Google Scholar
- 5.L. P. Korotkova et al., "Investigation of atomized powders of high-speed steels," Izv. Vyssh. Uchehn. Zaved. Mashinostr., No. 6, 91 (1980).Google Scholar