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Failure of a Pressure Regulator System by Crevice Corrosion: Attributed to Improper Material Selection

Authors :
K. P. Balan
Mrityunjoy Hazra
Source :
Journal of Failure Analysis and Prevention. 21:22-27
Publication Year :
2020
Publisher :
Springer Science and Business Media LLC, 2020.

Abstract

A pressure regulator in a system of the base shroud failed during service. The pressure regulator is intended to regulate the inlet pressure of 275 to 50 kg/cm2 outlet pressure. The working medium is stated to be nitrogen gas. On disassembly of the system, a brown layer was observed on the seating surface of poppet of the main regulator. A brown layer was also observed on the spring pocket and on the spring end surface which was in contact with the poppet. Metallographic tests and hardness measurement were carried out on the components to reach to the cause of failure. The poppet of the pressure regulator failed to function in service due to rusting of its seating surface by crevice corrosion and partial closure of the holes. The crevices at contact surface between the poppet and the spring seems to have formed by settlement of a stagnant condensed moisture along the surface. Partial closure of the holes was due to the presence of condensed moisture as well as rust. Spring made of AISI 302 austenitic stainless steel did not corrode at all, while poppet made of AISI 420 martensitic stainless steel corroded heavily.

Details

ISSN :
18641245 and 15477029
Volume :
21
Database :
OpenAIRE
Journal :
Journal of Failure Analysis and Prevention
Accession number :
edsair.doi...........ea428890255f0c476ab141cb379f1821
Full Text :
https://doi.org/10.1007/s11668-020-01069-4