Abstract：The element powder was used as the raw material, the uniformly distributed mixed powder was obtained by two steps ball-milling, and M2 high speed steel was obtained by compression molding and vacuum sintering. The effects of carbon contents on the phase composition, microstructure, density, bending strength and hardness of high speed steel were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and mechanical property testing. The results show that increasing the carbon contents can decrease the sintering temperature and achieve densification at lower temperature. The main components of the sintered samples are α-Fe, M6C carbides, MC carbides, and austenite. With the increase of carbon contents, the porosity of M2 high-speed steel decreases and the amount of granular carbides with regular shape increases, which is beneficial to the improvement of bending strength and hardness of the material. However, excessive carbon contents will lead to the precipitation and growth of carbides at grain boundaries and reduce the strength of high-speed steel.
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2019, Vol. 24 
