Failure analysis of a gas turbine marriage bolt

被引：16

作者：

Mohammadi M. ^{[1
]}

Salimi H.R. ^{[2
]}

机构：

[1] Department of Mechanical and Materials Engineering, The University of Western Ontario, London, ON N6G 1J5

[2] Department of Mechanical Engineering, Sharif University of Technology, Tehran

来源：

Journal of Failure Analysis and Prevention | 2007年 / 7卷 / 2期

关键词：

Coating Layer; Journal Shaft; Inlet Plenum; Scan Electron Microscope Inspection; Exhaust Diffuser;

D O I：

10.1007/s11668-007-9026-4

中图分类号：

学科分类号：

摘要：

A gas turbine which output 18MW power exploded after 3h of ordinary operation and after 4,785 starts. The turbine's rotor had undergone repair after 77,000 operating hours. A piece was cut from the failed marriage bolt and tested using atomic absorption spectrometry in order to know the grade of the alloy. It was found that the marriage bolt is made from ASTM A193 B16 steel which is suitable. Hardness and microhardness measurement was also determined and showed that it was within the range of the specified hardness for ASTM A193 B16 steel. The marriage bolt's mechanical properties also meet technical specifications and showed that it contained anti-corrosion properties. Visual examination showed that the marriage bolt was fractured near the first thread inside the nut which is due to the highest stress concentration and most severe loading. Deep corrosion pits were also observed which means that the bolt is exposed to aggressive corrosion environment. The presence of dimples show that he bolt fractured due to overload, not to mention deterioration of the coating layer which is due to fatigue assisted corrosion failure.

引用

页码：81 / 86

页数：5

共 3 条

[1]

ASTM E8M-90a. Standard Test Method for Tension Testing of Metallic Materials, 3, 1, (2001)

[2]

ASM Handbook. Failure Analysis and Prevention, 11, (1986)

[3]

Majzoobi G.H., Farrahi G.H., Hardy S.J., Pipelzadeh M.K., Habibi N., Experimental Results and Finite Element Predictions of the Effect of Nut Geometry, Washer and Teflon Tape on the Fatigue Life of Bolts, Fatigue and Fracture of Engineering Materials & Structures, 28, pp. 557-564, (2005)

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