Effects of austempering and tempering process on microstructure and mechanical properties of Cr-Ni-Mo-V alloy steel

doi:10.13251/j.issn.0254-6051.2024.06.009

Abstract

Abstract: Microstructure and mechanical properties of Cr-Ni-Mo-V alloy steel with bainite/martensite duplex structure formed by austempering during tempering were investigated. The orthogonal experiment scheme was designed with austempering temperature, austempering time and tempering temperature as factors. The effects of austempering and tempering process on the mechanical properties of the Cr-Ni-Mo-V ultra-high strength and toughness steel were explored by means of the impact testing machine combined with Vickers hardness tester, and the microstructure changes of the material were analyzed by scanning electron microscope and metallographic microscope. The results indicate that both the austempering temperature and tempering time have a significant effect on the microstructure and mechanical properties of the material, with the tempering time having a greater impact. During the tempering process, bainite transforms to tempered troostite and M/A islands gradually decompose. After austempering at 280 ℃ for 12 h and tempering at 560 ℃, the specimen shows the best impact property. After austempering at 280 ℃ for 50 min and non-tempering, the specimen shows the highest hardness, and the best heat treatment parameters are obtained after austempering at 280 ℃ for 12 h and tempering at 560 ℃, with impact absorbed energy of 60.0 J and the hardness of 518.7 HV2.

Key words: Cr-Ni-Mo-V alloy steel, duplex structure, heat treatment, austempering

CLC Number:

TG142.1

Yu Guining, Tian Ze, Wang Xuanru, Yan Sujia, Zhou Cong, Cao Tieshan, Qi Lin. Effects of austempering and tempering process on microstructure and mechanical properties of Cr-Ni-Mo-V alloy steel[J]. Heat Treatment of Metals, 2024, 49(6): 55-61.

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