Pre-heat treatment process for large size NiCrMoV steel forgings

doi:10.13251/j.issn.0254-6051.2025.02.037

Abstract

Abstract: In response to the problem of coarse grain and structural inheritance of high hardenability NiCrMoV steel forgings after forging, a process experiment using small-sized specimens was used to analyze the effect of heat treatment schemes such as pre-treatment before normalizing, multiple high-temperature normalizing treatments, two-phase region high-temperature side normalizing and annealing for cutting off the structural inheritance and for grain refinement. According to the size and shape characteristics of the rotor core shaft forgings, the optimal pre-heat treatment process scheme was developed, and control measures for austenitizing heating temperature and time and cooling process were proposed. The results show that after the optimal pre-heat treatment, the actual grain size of the actual produced large size forging body is sampled and tested as grade 6.5, and the ultrasonic testing of the forging meets the ø2 mm initial sensitivity requirement.

Key words: NiCrMoV steel, rotor core shaft forging, coarse grain, structural inheritance, pre-heat treatment

CLC Number:

TG142.1

Li Guang, Qin Hongfu, Li Jie, Su Wenbo, Li Liangyu, Jin Ming. Pre-heat treatment process for large size NiCrMoV steel forgings[J]. Heat Treatment of Metals, 2025, 50(2): 235-240.

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