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兵工学报 ›› 2025, Vol. 46 ›› Issue (6): 240532-.doi: 10.12382/bgxb.2024.0532

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深冷时间对低碳高合金马氏体钢组织性能的影响

何金1, 杨彬1, 王迎春1,2,*(), 迟宏宵3, 周健3, 程兴旺1,2   

  1. 1 北京理工大学 材料学院, 北京 100081
    2 冲击环境材料技术国家级重点实验室, 北京 100081
    3 钢铁研究总院特殊钢研究院, 北京 100081
  • 收稿日期:2024-07-04 上线日期:2025-06-28
  • 通讯作者:
  • 基金资助:
    国家科技重大专项项目(J2019-VI-0019-0134)

Effect of Cryogenic Treatment Time on Microstructure and Mechanical Properties of a Low-carbon High-alloy Martensite Steel

HE Jin1, YANG Bin1, WANG Yingchun1,2,*(), CHI Hongxiao3, ZHOU Jian3, CHENG Xingwang1,2   

  1. 1 School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
    2 National Key Laboratory of Science and Technology on Materials Under Shock and Impact, Beijing Institute of Technology, Beijing 100081, China
    3 Institute for Special Steels, Central Iron and Steel Research Institute, Beijing 100081, China
  • Received:2024-07-04 Online:2025-06-28

摘要:

为了控制残余奥氏体含量以获得更高性能的航空轴承钢,优化深冷处理工艺是有效的途径。研究深冷时间对经淬火、-75℃下深冷和回火处理后的低碳Co-Cr-Mo-Ni-W高合金钢组织和力学性能影响,结果表明:深冷回火后试验钢的组织主要为回火马氏体,同时还有一定量残余奥氏体和细小均匀分布在基体上的纳米碳化物;在2~6h范围内,随着深冷时间延长,由于残余奥氏体含量降低,回火马氏体板条细化,位错密度提高,纳米级碳化物数量增加且分布均匀化,强度显著提高,塑性逐渐降低;深冷时间超过6h后,残余奥氏体含量继续减小,位错密度增加,纳米碳化物尺寸长大,数量减少,强度和塑性均变化不大;试验条件下,深冷时间为6~10h时,获得了超高强度和良好的强塑性匹配,屈服和抗拉强度分别为~1690MPa和~1940MPa,延伸率为~14.3%。

关键词: 低碳高合金钢, 深冷处理, 残余奥氏体, 纳米碳化物, 力学性能

Abstract:

To achieve the superior performance of aerospace bearing steel by controlling the retained austenite content,the optimization of cryogenic treatment parameters is an effective approach.The microstructure and mechanical properties of a low-carbon Co-Cr-Mo-Ni-W high-alloy martensite steel after quenching,cryogenic treatment at -75℃ for different times and tempering are investigated.The results show that the microstructure of the martensite steel after cryogenic tempering contains the complex phases with tempered martensite,retained austenite and nano-carbides.As the cryogenic time increases from 2 to 6h,the strength of the steel significantly improves and its ductility reduces due to the refinement of tempered martensite lath and the decrease in residual austenite volume fraction,the increase in dislocation density and the increase in the quantity of nano-carbides with more uniform distribution.When the cryogenic time exceeds 6h,the strength and ductility of the steel change slightly because the retained austenite volume fraction decreases,the dislocation density increases and the nano-carbide sizes coarsen with the decrease in quantity.An excellent balance of strength and ductility,with the mean yield strength of about 1690MPa,the ultimate strength of about 1940MPa and the mean elongation of about 14.3%,is achieved for the steel after quenching,cryogenic treatment for 6-10h and tempering.

Key words: low-carbon high-alloy steel, cryogenic treatment, retained austenite, nano-carbide, mechanical property