Journal of Failure Analysis and Prevention

, Volume 15, Issue 4, pp 555–562 | Cite as

Failure Analysis of Micro Cracks and Alumina Inclusions Induced Insulator Pin’s Low Stress Mode of Fracture

Technical Article---Peer-Reviewed
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Abstract

A tensile test must be conducted for each finished insulator in which a common but significant problem is a low stress mode of fracture. In order to investigate the cause of the low stress fracture in a batch of insulators, a series of failure analysis methods were carried out. As described in this paper, macro-fracture analysis, SEM observation, EDS examination, metallographic structure analysis, hardness test, and inclusion rating were all conducted on the investigation. The results of this investigation show that the major cause of incident fracture is micro cracks in the pin, which are the result of both the molding method and the heating treatment. However, the major reason for the macro cracks lies in the induction heating process, which lacked the accurate temperature control method and using of higher electric power. Furthermore, alumina inclusions in the pin were in excess of standard, so they may also have contributed to the low stress fracture of the pin.

Keywords

Insulator pin Low stress fracture Micro cracks Alumina inclusions Induction heating 

Notes

Acknowledgments

This paper is supported by the National Demonstration Central of Experimental Education of Materials Science and Engineering and the Key Lab of Advanced Technologies of Materials in Southwest Jiaotong University.

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Copyright information

© ASM International 2015

Authors and Affiliations

  • Qiangyun Yang
    • 1
  • Hui Zhao
    • 1
  • Wuqian Chai
    • 1
  • Chuan Yang
    • 1
  1. 1.College of Materials Science and EngineeringSouthwest Jiaotong UniversityChengduChina

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