金属热处理 ›› 2025, Vol. 50 ›› Issue (6): 270-275.DOI: 10.13251/j.issn.0254-6051.2025.06.041

• 表面工程 • 上一篇    下一篇

渗碳工艺对18CrNiMo7-6齿轮钢渗层组织的影响

田学锋1, 肖金1, 宋小春2   

  1. 1.广东松山职业技术学院 先进制造学院, 广东 韶关 512126;
    2.华南理工大学 机械与汽车工程学院, 广东 广州 510641
  • 收稿日期:2024-12-03 修回日期:2025-03-19 出版日期:2025-06-25 发布日期:2025-07-08
  • 作者简介:田学锋(1974—),男,副教授,博士,主要研究方向为金属材料组织演变及成形工艺,E-mail: tianxuefeng05@163.com
  • 基金资助:
    国家自然科学基金(52001123);韶关市科技计划(210806154531768)

Effect of carburizing process on microstructure of carburied layer of 18CrNiMo7-6 gear steel

Tian Xuefeng1, Xiao Jin1, Song Xiaochun2   

  1. 1. School of Advanced Manufacturing, Guangdong Songshan Polytechnic, Shaoguan Guangdong 512126, China;
    2. School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou Guangdong 510641, China
  • Received:2024-12-03 Revised:2025-03-19 Online:2025-06-25 Published:2025-07-08

摘要: 以高性能18CrNiMo7-6齿轮钢为研究对象,对其进行不同渗碳温度和淬火方式的渗碳处理,采用金相显微镜、X射线衍射仪和硬度计对渗碳层组织和硬度进行表征。结果表明,在930~1020 ℃渗碳温度范围内,随着渗碳温度的升高,渗碳层深度由1.51 mm增加至2.23 mm,渗碳层的峰值硬度逐渐下降,930 ℃渗碳层峰值硬度最高,为751 HV0.2。随着渗碳温度的升高,碳化物、针状马氏体以及残留奥氏体均发生粗化,当渗碳温度超过990 ℃时粗化最为明显。渗碳后两次淬火处理试样中残留奥氏体含量较直接淬火处理降低了8%,渗碳层硬度由751 HV0.2提高到762 HV0.2,且渗碳层深度为1.53 mm,略大于直接淬火试样。综合考虑,18CrNiMo7-6钢渗碳温度不宜超过990 ℃,且优先选择两次淬火工艺。

关键词: 齿轮钢, 渗碳层, 渗碳温度, 淬火工艺, 组织, 硬度

Abstract: Taking high-performance 18CrNiMo7-6 gear steel as the research object, carburizing treatment was carried out at different carburizing temperatures and quenching methods. The microstructure and hardness of carburized layer were characterized by using metallographic microscope, X-ray diffractometer, and hardness tester. The results show that in the carburizing temperature range of 930-1020 ℃, with the increase of carburizing temperature, the depth of carburized layer increases from 1.51 mm to 2.23 mm, and the peak hardness of carburized layer decreases gradually. The peak hardness of carburized layer is the highest at 930 ℃, which is 751 HV0.2. With the increase of carburizing temperature, the carbides, acicular martensite and retained austenite all undergo coarsening. When the carburizing temperature exceeds 990 ℃, the coarsening is the most obvious. The content of retained austenite in the double quenched specimen after carburizing is 8% lower than that of the direct quenched specimen, the hardness of carburized layer increases from 751 HV0.2 to 762 HV0.2, and the depth of carburized layer is 1.53 mm, which is slightly greater than that of the direct quenched specimen. Overall consideration, the carburizing temperature of the 18CrNiMo7-6 steel should not exceed 990 ℃, and double quenching process is preferably selected.

Key words: gear steel, carburized layer, carburizing temperature, quenching process, microstructure, hardness

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