Journal of Failure Analysis and Prevention

, Volume 16, Issue 2, pp 302–309 | Cite as

Failure and Fracture Analysis of Bolt Assembled on the Fan Used in the Internal Combustion Engine

  • Jingbao Zhang
  • Ai Li
  • Chengsong Zhang
  • Chuan Yang
Technical Article---Peer-Reviewed


Three connecting bolts fractured, which were assembled on the fan used in the internal combustion engine. Detailed fractographic study and metallurgical analysis were focused on the fractured bolts. Fractographic and metallurgical studies indicate that the fracture surface and the microstructure of three bolts exhibit similar features. The fatigue fracture is the main failure mechanism of the bolts. Appearance of the micro-cracks in the thread tip of the fractured bolts makes the stress at the thread regions increase intensively so that the fatigue cracks initiated from the thread regions. Due to the presence of dynamic load, the bolts were never properly tightened during installation which should be responsible for the formation of the cracks.


Fractured bolt Fractography Micro-cracks Dynamic load Fatigue 


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Copyright information

© ASM International 2016

Authors and Affiliations

  • Jingbao Zhang
    • 1
  • Ai Li
    • 1
  • Chengsong Zhang
    • 1
  • Chuan Yang
    • 1
  1. 1.College of Materials Science and EngineeringSouthwest Jiaotong UniversityChengduChina

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