金属热处理 ›› 2020, Vol. 45 ›› Issue (4): 137-140.DOI: 10.13251/j.issn.0254-6051.2020.04.028

• 工艺研究 • 上一篇    下一篇

直流电场对40Cr钢的低温QPQ催渗

杜航1, 罗德福1, 陈甥怡2, 罗俊1   

  1. 1. 西华大学 材料科学与工程学院, 四川 成都 610000;
    2. 湖南红宇耐磨新材料股份有限公司, 湖南 长沙 410000
  • 收稿日期:2019-09-23 出版日期:2020-04-25 发布日期:2020-05-08
  • 通讯作者: 罗德福,教授,E-mail:cd df@126.com
  • 作者简介:杜 航(1994—),男,硕士研究生,主要从事金属材料表面改性研究工作,E-mail:18408230091@163.com

Low temperature QPQ accelerating nitriding for 40Cr steel by applying DC electric field

Du Hang1, Luo Defu1, Chen Shengyi2, Luo Jun1   

  1. 1. College of Materials Science and Engineering, Xihua University, Chengdu Sichuan 610000, China;
    2. Hunan Hongyu Wear-resistant New Materials Co., Ltd., Changsha Hunan 410000, China
  • Received:2019-09-23 Online:2020-04-25 Published:2020-05-08

摘要: 以40Cr作为基体材料,研究了施加直流电场对450 ℃低温QPQ处理时的加速渗氮。对处理后试样的渗层组织、渗层厚度、渗层硬度及物相进行了分析,并对低温QPQ直流电场加速渗氮的机理进行了分析。结果表明:通入直流电场保温2 h后试样的化合物层可达18 μm,与无直流电场保温17 h的化合物层厚度相近,显著提高了渗氮速度。施加直流电场后的40Cr钢表面硬度达到813 HV0.1,是无直流电场硬度的1.3倍。直流电场能够使阳极试样周围聚集CNO-离子,并为CNO-离子的分解提供额外能量,获得更多渗氮所需的活性氮原子,从而达到催渗效果。

关键词: QPQ工艺, 直流电场, 加速渗氮, 机理

Abstract: Using 40Cr as the matrix material, the low temperature QPQ nitriding process at 450 ℃ was accelerated by applying direct current (DC) electric field and the corresponding mechanism was studied. The microstructure, thickness, hardness and phases of the nitriding layer of the treated samples were analyzed. The results show that when the DC electric field is applied and holding for 2 h, the compound layer thickness of the sample can reach 18 μm, which is similar to that of nitriding for 17 h without DC electric field. It means that the DC electric field significantly increases the nitriding speed. The surface hardness of the steel reaches 813 HV0.1 after applying DC electric field, which is 1.3 times of that without DC electric field. The DC electric field can make more CNO- ions to exist around the anode sample, providing extra energy for the decomposition of CNO- ions and obtaining more active nitrogen atoms required for nitriding, so as to achieve the accelerating effect of infiltration.

Key words: QPQ process, direct current electric field, accelerated nitriding, mechanism

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