山东科学 ›› 2023, Vol. 36 ›› Issue (2): 69-75.doi: 10.3976/j.issn.1002-4026.2023.02.009

• 新材料 • 上一篇    下一篇

铁路钢桥高强度紧固螺栓断裂分析及防护

郭卫民1, 董有福2, 雷太安2, 张钦然2, 刘国强3, 刘国飞4, 孟令强4, 田力男1, 丁宁1,*()   

  1. 1.齐鲁工业大学(山东省科学院) 山东省分析测试中心 山东省材料失效分析与安全评估工程技术研究中心,山东 济南 250014
    2.山东高速轨道交通集团有限公司 益羊铁路管理处,山东 潍坊 261000
    3.齐鲁工业大学(山东省科学院) 山东省机械设计研究院,山东 济南 250031
    4.铁正检测科技有限公司,山东 济南 250014
  • 收稿日期:2022-04-06 出版日期:2023-04-20 发布日期:2023-04-11
  • 通信作者: *丁宁,女,副研究员,研究方向为机械结构失效分析及安全评估。Tel:13280020902,E-mail: dingningch@aliyun.com E-mail:dingningch@aliyun.com
  • 作者简介:郭卫民(1984—),女,博士,助理研究员,研究方向为金属结构件断裂与失效分析。
  • 基金资助:
    山东省自然科学基金面上项目(ZR2021ME158);山东省自然科学基金面上项目(ZR2021ME148);齐鲁工业大学科研项目(2022PY034);齐鲁工业大学科研项目(2022PX065);齐鲁工业大学科研项目(2022PX068);山东省“泰山学者”特聘专家专项经费;山东省重点研发计划(2017GSF220004);山东省科学院科研项目(2020QN003);山东省科学院科研项目(2019GHPY11);山东省科学院科研项目(KJHZ201805)

Fracture analysis and prevention of high-strength fastening bolts used in railway steel bridges

GUO Weimin1, DONG Youfu2, LEI Tai'an2, ZHANG Qinran2, LIU Guoqiang3, LIU Guofei4, MENG Lingqiang4, TIAN Linan1, DING Ning1,*()   

  1. 1. Research Center of Failure Analysis and Engineering Safety Assessment, Shandong Analysis and Test Center, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250014, China
    2. Yiyang Railway Management Office of Shandong Hi-Speed Rail Transit Group Co., Ltd., Weifang 261000,China
    3. Shandong Institute of Mechanical Design and Research, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250031, China
    4. Tiezheng Testing Technology Co., Ltd., Jinan 250014, China
  • Received:2022-04-06 Online:2023-04-20 Published:2023-04-11

摘要:

为探求高强度紧固螺栓发生断裂的原因,对某铁路钢桥上断裂的紧固螺栓进行了失效分析。利用扫描电子显微镜、能量色散X射线谱、金相显微镜、洛氏硬度仪、X射线荧光光谱仪、电子万能试验机等技术手段,对铁路钢桥失效螺栓的断口形貌、断口微区成分、显微组织、硬度、螺栓用钢的成分以及力学性能等方面进行分析与研究。结果显示:螺栓用钢的化学成分、硬度及力学性能均符合国家标准要求;螺栓断口起裂区存在树枝状裂纹,裂纹内部有含硫的腐蚀产物,且螺栓工作时所受外力为交变载荷。因此,螺栓的断裂是在交变载荷下发生的腐蚀疲劳断裂。螺栓断裂的初始裂纹源位于螺杆上螺纹的根部或螺柱与螺母连接位置的根部,为由硫元素引起的应力腐蚀裂纹。此研究为防止螺栓发生应力腐蚀裂纹及衍生病害提供了理论依据。

关键词: 钢桥, 高强螺栓, 应力腐蚀裂纹, 疲劳, 断裂

Abstract:

Several high-strength fastening bolts were found broken on a railway steel bridge. Failure analysis of these bolts was performed to determine why they fractured and to prevent future bolt fractures. The fracture morphology, microarea-chemical analysis of the fracture, microstructure and hardness of the bolts, compositional contents, and mechanical properties of the bolt steel were analyzed by using scanning electron microscopy, energy dispersive X-ray spectrometry, optical microscopy, a Rockwell hardness tester, X-ray fluorescence spectrometry, and an electronic universal testing machine, respectively. The results indicate that the compositional contents, hardness, and mechanical properties are consistent with the 20MnTiB steel standard. In addition, dendritic cracks can be observed in the fracture initiation zones of the fastening bolts and the corrosion products in the cracks contain sulfur.The fastening bolts are subjected to cyclic loads in normal working conditions. Therefore, fractures of the fastening bolts were caused by corrosion fatigue fractures under cyclic loads. The cracks initiated at the root of the screw thread or the connecting point between the stud and nut, which are particularly vulnerable to stress corrosion cracks caused by the presence of sulfur.

Key words: steel bridge, high strength bolt, stress corrosion crack, fatigue, fracture

中图分类号: 

  • TG115