Abstract: The types, morphology, composition and distribution of carbides in 7Cr5Mo2V steel during quenching and tempering were studied by scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM) and energy dispersive spectroscopy (EDS).The experiment results showed that after quenching at 1 030 ℃ and tempering at 400 ℃, coarsen Cr-rich and Fe-rich M7C3 carbides in the 7Cr5Mo2V steel led to the hardness drop. And fine secondary V6C5 and Mo2C should be responsible for the secondary hardening peak when tempered at 550 ℃. After aging at 550 ℃ for 24 hours, V-rich carbides were noodle-like and Mo-rich carbides were short rod-like. After aging at 550 ℃ for 48 hours,V6C5 grew into micron-sized in length while Mo2C transformed into spherical Mo6C. The dissolution of alloy cementite was delayed during 550 ℃ aging, which was attributed that about 57.3% of Fe was substituted by Cr and Mo.
孙朋朋, 闵娜, 左鹏鹏, 吴晓春. 7Cr5Mo2V冷作模具钢回火特性研究[J]. 材料导报, 2019, 33(z1): 377-381.
SUN Pengpeng, MIN Na, ZUO Pengpeng, WU Xiaochun. Study on the Tempering Characteristics of 7Cr5Mo2V Cold Work Die Steel. Materials Reports, 2019, 33(z1): 377-381.
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