金属热处理 ›› 2025, Vol. 50 ›› Issue (7): 335-338.DOI: 10.13251/j.issn.0254-6051.2025.07.049

• 测试与分析 • 上一篇    下一篇

40Cr钢销轴轴向开裂原因分析

金丽君1, 代玉杰2, 毕高杰1   

  1. 1.青岛征和工业股份有限公司, 山东 青岛 266705;
    2.青岛金链检测技术服务有限公司, 山东 青岛 266705
  • 收稿日期:2025-02-24 修回日期:2025-05-29 出版日期:2025-07-25 发布日期:2025-07-28
  • 通讯作者: 代玉杰,高级工程师,硕士,E-mail:yujiedaiqd@163.com
  • 作者简介:金丽君(1975—),女,正高级工程师,学士,主要研究方向为链传动系统设计开发,E-mail:lj0638@163.com。

Causes analysis of axial cracking of 40Cr steel pin shaft

Jin Lijun1, Dai Yujie2, Bi Gaojie1   

  1. 1. Qingdao Choho Industrial Co., Ltd., Qingdao Shandong 266705, China;
    2. Qingdao Gold Chain Detection Technology Service Co., Ltd., Qingdao Shandong 266705, China
  • Received:2025-02-24 Revised:2025-05-29 Online:2025-07-25 Published:2025-07-28

摘要: 通过金相显微镜、洛氏硬度计和直读光谱仪对纵向开裂的40Cr钢销轴进行分析。结果表明,40Cr钢销轴的化学成分满足GB/T 3077—2015《合金结构钢》标准要求,裂纹处及其附近的非金属夹杂物较少,显微组织为细针状回火马氏体。裂纹两侧未见脱碳、氧化、折叠形貌,为典型的淬火纵向裂纹。销轴纵向开裂原因为销轴淬火时采用20~30 ℃的水冷却,造成销轴冷却速度过快,淬火后又未及时回火,导致销轴表面的拉应力过大,从而导致销轴表面纵向开裂。

关键词: 40Cr钢, 销轴, 淬火裂纹, 淬火介质, 回火

Abstract: Longitudinal cracking cause of 40Cr steel pin shaft was analyzed by metallographic microscope, Rockwell hardness tester and direct reading spectrometer. The results indicate that the chemical composition of the 40Cr steel pin shaft meets the requirement of the standard GB/T 3077—2015 “Alloy structure steels”, with fewer non-metallic inclusions at and near the crack, and fine needle-like tempered martensite. No decarburization, oxidation, or folding morphology is observed on both sides of the crack, indicating a typical longitudinal quenching crack. The reason for the longitudinal cracking of the pin shaft is that the pin shaft is cooled with water at 20-30 ℃ during quenching, which causes the cooling rate of the pin shaft to be too fast. After quenching, it is not tempered in time, resulting in excessive tensile stress on the surface of the pin shaft, thus forming longitudinal cracking on the surface of the pin shaft.

Key words: 40Cr steel, pin shaft, quenching crack, quenching medium, tempering

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