金属热处理 ›› 2021, Vol. 46 ›› Issue (11): 110-119.DOI: 10.13251/j.issn.0254-6051.2021.11.017

• 工艺研究 • 上一篇    下一篇

65Mn钢渗硼层的微观组织、硬度及生长动力学

魏祥1, 蒋彦清1, 庾灵颉1, 彭广威1, 鱼宏斌2, 郝鹏磊3   

  1. 1.湖南人文科技学院 材料工程系, 湖南 娄底 417000;
    2.湖南华菱涟源钢铁有限公司, 湖南 娄底 417009;
    3.陕西法士特汽车传动集团有限责任公司, 陕西 宝鸡 722409
  • 收稿日期:2021-08-17 出版日期:2021-11-25 发布日期:2021-12-08
  • 作者简介:魏 祥(1988—),男,讲师,博士,主要研究方向为高性能耐磨材料,E-mail:hnwxiang@126.com
  • 基金资助:
    湖南省自然科学基金(2020JJ5274);湖南省教育厅项目(19B292)

Microstructure, hardness and growth kinetics of 65Mn steel borided layer

Wei Xiang1, Jiang Yanqing1, Yu Lingjie1, Peng Guangwei1, Yu Hongbin2, Hao Penglei3   

  1. 1. Department of Materials Engineering, Hunan University of Humanities, Science and Technology, Loudi Hunan 417000, China;
    2. Valin Lianyuan Steel Co., Ltd., Loudi Hunan 417009, China;
    3. Shanxi Fast Auto Drive Group Co., Ltd., Baoji Shaanxi 722409, China
  • Received:2021-08-17 Online:2021-11-25 Published:2021-12-08

摘要: 采用固体渗硼工艺对65Mn钢进行渗硼处理,并借助光学显微镜、X射线衍射仪、电子探针及维氏硬度计等手段系统研究了渗硼温度(800~1000 ℃)和渗硼保温时间(2~8 h)对65Mn钢渗硼层厚度、微观组织和硬度的影响规律以及渗硼层的生长动力学。结果表明,随着渗硼温度的升高或渗硼时间的延长,渗硼层的厚度不断增大,但当渗硼温度超过900 ℃时,渗硼层中黑色孔洞的数量、大小以及距离渗硼层表面的深度都逐渐增大。65Mn钢渗硼层都由Fe2B柱状晶,以及位于Fe2B柱状晶生长前沿及晶粒间的Fe3(B,C)相、二元铁硅化合物和三元铁碳硅化合物组成,其维氏硬度(800~1590 HV0.05)远大于65Mn钢基体的硬度(238 HV0.05)。由于硬度较低的Fe3(B,C)相和富硅相分布于高硬度的Fe2B柱状晶晶粒之间,导致渗硼层的硬度并不随离渗硼层表面距离的增加而单调减小。渗硼层厚度的平方与渗硼时间呈线性关系,B原子在65Mn钢渗硼层中的扩散激活能为220.96 kJ/mol。

关键词: 65Mn钢, 渗硼层, 硬度, 微观组织, 生长动力学

Abstract: Effects of boriding temperature (800-1000 ℃) and boriding time (2-8 h) on the thickness, microstructure and hardness of the borided layers on 65Mn steel by pack boriding and its growth kinetics were systematically investigated by optical microscope, XRD, EPMA and Vickers hardness tester, etc. The results show that with the increase of boriding temperature or time, the thickness of the borided layers increases continuously, but the amount, size and depth away from the surface of borided layer of black holes also increase gradually when the boriding temperature exceeds 900 ℃. The layers are composed of Fe2B columnar crystals, Fe3(B,C) phase, Fe-Si binary compounds and Fe-C-Si ternary compounds, and the later three are formed between and in the front of Fe2B columnar crystals. The hardness of the layers (800-1590 HV0.05) is greatly higher than that of the 65Mn steel (238 HV0.05). However, it is found that the hardness values of the borided layers are not monotonically decreasing when the distance from the surface of the layers is increasing, which should be attributed to the Fe3(B,C) and Si-rich phases with lower hardness distributed between the Fe2B columnar crystals with higher hardness. There is a liner relationship between square of the thickness of borided layer and boriding time, and the calculated diffusion activation energy of boron atoms in borided layer on the 65Mn steel is 220.96 kJ/mol.

Key words: 65Mn steel, borided layer, hardness, microstructure, growth kinetics

中图分类号: