In-situ observation of carbide precipitation behavior in Cr8Mo2SiV steel

doi:10.13251/j.issn.0254-6051.2025.03.034

Abstract

Abstract: Focusing on Cr8Mo2SiV ledeburite cold working die steel with high carbon and medium chromium content, the evolution of eutectic carbides (M₇C₃) and secondary carbides (M₇C₃) during the process of heating, holding and cooling was in-situ observed by using a high-temperature laser scanning confocal microscope. The results show that when the heating temperature exceeds 1180 ℃, the low-melting eutectic phase undergoes remelting, leading to pronounced overheating and overburning phenomena around the grain boundaries. Furthermore, The higher the holding temperature is, the higher the precipitation temperature of secondary carbides during the cooling process is. As the holding temperature rises from 1160 ℃ to 1200 ℃, Mo-rich particulate metastable carbides located at the grain boundaries dissolve, and the alloy elements enriched in the elongated dendritic secondary carbides continuously diffuse into the matrix. The difference in alloy element content between the matrix and the carbides is reduced gradually.

Key words: cold working die steel, carbide, in-situ observation, precipitation morphology

CLC Number:

TG156

He Shuai, Hong Xiaoli, Zhao Jinhuan, Liu Xin, Qin Zhe, Wang Junsheng. In-situ observation of carbide precipitation behavior in Cr8Mo2SiV steel[J]. Heat Treatment of Metals, 2025, 50(3): 214-219.

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