Effect of austenitizing temperature on microstructure and properties of a high-speed cobalt steel
Author:
Pan Yongliang1, Jin Tounan1, Yuan Naibo2, Ma Tiejun1, Fu Hanguang1
Affiliation:
1. Beijing University of Technology , Beijing , China 2. Xingtai Delong Machinery Roll Co., Ltd , Xingtai , China
Abstract
Abstract
The effect of different austenitizing temperatures on the type, morphology, distribution of carbides and martensite content in cobalt high-speed steel is characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and energy dispersive spectrometry. The results show that the eutectic MC carbides hardly dissolve during austenitizing process, and the lamellar M2C carbides decompose into MC and M6C carbides at 1100 °C. A large amount of M23C6 carbides uniformly distributed on the matrix are dissolved into austenite at 1100 °C. With the increase of austenitizing temperature, alloy element dissolves into matrix and the effect of solid solution strengthening of martensite enhances, which increases the hardness of cobalt high-speed steel. However, when the austenitizing temperature exceeds 1050 °C, the excess alloying elements in the matrix reduce the Ms point and increase the volume fraction of retained austenite, resulting in decrease of hardness of cobalt high-speed steel. The peak hardness with 66.4 HRC appears when the austenitizing temperature reaches 1050 °C.
Funder
National Natural Science Foundation of China Hebei Science and Technology Major Project
Publisher
Walter de Gruyter GmbH
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science
Reference25 articles.
1. C. K. Kim, Y. C. Kim, J. I. Park, S. Lee, N. J. Kim, and J. S. Yang, “Effects of alloying elements on microstructure, hardness, and fracture toughness of centrifugally cast high-speed steel rolls,” Metall. Mater. Trans. A., vol. 36, no. 1, pp. 87–97, 2005, https://doi.org/10.1007/s11661-005-0141-0. 2. Y. Sano, T. Hattori, and M. Haga, “Characteristics of high-carbon high speed steel rolls for hot strip mill,” ISIJ Int., vol. 32, no. 11, pp. 1194–1201, 1992, https://doi.org/10.2355/isijinternational.32.1194. 3. X. F. Zhou, F. Fang, F. Li, and J. Q. Jiang, “Morphology and microstructure of M2C carbide formed at different cooling rates in AISI M2 high speed steel,” J. Mater. Sci., vol. 46, no. 5, pp. 1196–1202, 2011, https://doi.org/10.1007/s10853-010-4895-4. 4. M. A. Carvalho, R. R. Xavier, C. D. Pontes, C. Morone, M. Bocallini, and A. Sinatora, “Microstructure, mechanical properties and wear resistance of high speed steel rolls for hot rolling mills” in 42nd Mechanical Working and Steel Processing Conference, Toronto, Canada, Iron & Steel Society, 2000, pp. 685–694. 5. C. K. Kim, D. G. Lee, and S. Lee, “Correlation of microstructure and fracture properties of five centrifugal cast high speed steel rolls,” Mater. Sci. Technol., vol. 23, no. 9, pp. 1065–1074, 2007, https://doi.org/10.1179/174328407x213170.
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