Failure of AISI 304H stainless steel elbows in a heat exchanger

A. Bahrami, S. H. Mousavi Anijdan, P. Taheri, M. Yazdan Mehr*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

14 Citations (Scopus)


This work investigates the effects of grain boundary oxidation on the failure of AISI 304H stainless steel elbows in a heat exchanger in a power plant after 8 years of service at 400 °C. Optical and electron microscopes, elemental mapping, electron dispersive spectroscopy (EDS), inductively-coupled plasma atomic energy spectroscopy (ICP-AES) and hardness tester were used to understand the failure mechanism. Elemental mapping of the samples operating for 8 years showed high concentrations of oxygen and carbon at the grain boundaries. Results showed that cracks were propagated along the grain boundaries due to the brittleness of the oxide layer at the boundaries. Results confirmed the intergranular and brittle nature of the fracture. Microhardness profilometry showed that oxidized/carburized grain boundaries are significantly harder than matrix inside grains.

Original languageEnglish
Pages (from-to)397-403
JournalEngineering Failure Analysis
Publication statusPublished - 2018


  • 304H stainless steel
  • Failure
  • Grain boundary oxidation
  • Heat exchanger


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