金属热处理 ›› 2020, Vol. 45 ›› Issue (11): 78-82.DOI: 10.13251/j.issn.0254-6051.2020.11.015

• 工艺研究 • 上一篇    下一篇

18CrNiMo7-6齿轮钢温锻后余热等温正火工艺

王会珍, 翟月雯, 周乐育   

  1. 北京机电研究所有限公司, 北京 100083
  • 收稿日期:2020-08-10 出版日期:2020-11-25 发布日期:2020-12-29
  • 作者简介:王会珍(1984—),女,高级工程师,博士研究生,主要研究方向为材料热处理,E-mail: wanghzh@jds.ac.cn
  • 基金资助:
    国家科技重大专项(2018ZX04024001-002)

Isothermal normalizing process of 18CrNiMo7-6 gear steel directly after warm forging

Wang Huizhen, Zhai Yuewen, Zhou Leyu   

  1. Beijing Research Institute of Mechanical and Electrical Technology Ltd., Beijing 100083, China
  • Received:2020-08-10 Online:2020-11-25 Published:2020-12-29

摘要: 对18CrNiMo7-6齿轮钢进行了温锻余热等温正火工艺研究。结果表明:在温锻余热等温正火工艺中,冷却速度、等温温度、等温时间为关键的工艺参数。较低冷却速度和较高的等温温度,可在有限等温时间内有效提高珠光体的转变量,减少残留奥氏体含量及室温马氏体和贝氏体等非平衡组织,获得理想的组织及性能。以0.1 ℃/s和1 ℃/s冷却速度降至等温正火温度650 ℃保温1 h 后冷却可获得硬度163~164 HBS,F晶粒度10~11.5级,带状组织1.5级,组织及性能均符合技术要求,可具有良好的切削加工性能,并为后续热处理工艺提供理想组织。

关键词: 齿轮钢, 温锻, 等温正火, 硬度, 显微组织

Abstract: Isothermal normalizing of 18CrNiMo7-6 gear steel directly after warm forging was studied. The results show that the cooling rate, isothermal temperature and isothermal time are the key process parameters in the isothermal normalizing process utilizing residual warm forging heat. Lower cooling rate and higher isothermal temperature can effectively improve pearlite transformation in limited isothermal time, reduce the content of retained austenite and non-equilibrium microstructure such as martensite and bainite at room temperature, and therefore obtain ideal microstructure and properties. The hardness of 163-164 HBS, ferrite grain size of grade 10-11.5 and banded structure of grade 1.5 can be obtained by the process of cooling rate of 0.1 ℃/s and 1 ℃/s and isothermal temperature of 650 ℃ for 1 h. The microstructure and properties can meet the technical requirements, meanwhile it has good machinability and provides ideal microstructure for subsequent heat treatment process.

Key words: gear steel, warm forging, isothermal normalizing, hardness, microstructure

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