Abstract：The types and precipitation behavior of carbides in M2 high speed steel were studied. On the one hand，the scanning electron microscope was used to observe the morphology and distribution of carbides，and the chemical composition of these carbides was detected by energy dispersive spectroscopy. On the other hand，the Thermo-Calc was used to calculate the precipitation of carbides in equilibrium and Scheil model meanwhile. In the M2 HSS after annealing，the large carbides distributed along the network，which included MC，M6C，M2C carbides and mixture of them. After forging，the zonal distribution and accumulation of carbides arised in M2 HSS. MC and M6C carbides precipitate at 1 294 and 1 288 ℃ respectively in equilibrium，higher than the austenitizing temperature. However，in Scheil solidification，MC，M6C and M2C carbide would precipitate in turn. It is difficult to eliminate large carbides in M2 HSS through heat treating and forging，but controlling the precipitation of carbides could be of great significance.
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2018, Vol. 53 
