金属热处理 ›› 2021, Vol. 46 ›› Issue (2): 213-217.DOI: 10.13251/j.issn.0254-6051.2021.02.040

• 测试与分析 • 上一篇    下一篇

40CrNiMo7钢锻轴淬火开裂的原因分析

张家文, 付天亮, 吴昊, 王昭东   

  1. 东北大学 轧制技术及连轧自动化国家重点实验室, 辽宁 沈阳 110819
  • 收稿日期:2020-07-29 出版日期:2021-02-25 发布日期:2021-05-08
  • 通讯作者: 付天亮,副教授,博士,E-mail:futianliang@126.com
  • 作者简介:张家文(1996—),男,硕士研究生,主要研究方向为钢铁材料热处理工艺与组织性能,E-mail:1119589043@qq.com。

Cause analysis on quenching cracking of 40CrNiMo7 steel forged shaft

Zhang Jiawen, Fu Tianliang, Wu Hao, Wang Zhaodong   

  1. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang Liaoning 110819, China
  • Received:2020-07-29 Online:2021-02-25 Published:2021-05-08

摘要: 通过宏观形貌观察、化学成分分析、硬度测试、金相分析、能谱分析等方法,对40CrNiMo7钢锻轴开裂的原因进行了分析讨论。结果表明,锻轴的裂纹属于淬火纵向裂纹,钢中Cr元素含量偏高,增加了开裂倾向,试样表层有较多TiN夹杂物以及Al2O3、MnS等夹杂,同时试样有0.6 mm左右的脱碳层,促进了裂纹的形成。淬火时产生的组织应力使表面呈现拉应力状态,并在脱碳层和非金属夹杂物的影响下超过了材料的断裂强度而产生了开裂。

关键词: 40CrNiMo7钢, 淬火开裂, 组织应力, 脱碳层, 夹杂物

Abstract: Causes of 40CrNiMo7 steel forged shaft cracking were analyzed by means of macroscopic morphology observation, chemical composition analysis, hardness test, metallographic analysis, energy spectrum analysis and other methods. The results show that the crack of the forged shaft is a longitudinal quenching crack, due to that the Cr element in the steel exceeds the standard, and increases the cracking tendency. The specimen surface has more TiN inclusions and Al2O3, MnS etc., and a decarburized layer of about 0.6 mm, which promotes the formation of cracks. The generated structural stress during quenching causes the surface to exhibit a tensile stress state, and with the help of decarburized layer and non-metallic inclusions, the fracture strength of the material is exceeded and cracking occurs.

Key words: 40CrNiMo7 steel, quenching cracking, structural stress, decarburized layer, inclusions

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