Annealing of Shot Peened Austenitic Superheater Tubes and Its Consequences for Steamside Oxidation

Karen Pantleon*, Felix Lampert, Melanie Montgomery

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Surface modifications offer promising solutions to increase the lifetime and performance of superheaters in industrial applications. The surface and internal structure of the steamside of austenitic superheater tubes of TP347H austenitic stainless steel was modified by shot peening and the thermal stability of the microstructure at the surface was followed in-situ and ex-situ during subsequent isothermal annealing. At various industrially relevant temperatures, the kinetics of microstructure evolution near the surface was investigated by applying complementary methods of microscopy and diffraction analysis. The beneficial effect of shot peening on reducing steamside oxidation was confirmed both on laboratory scale mimicking the real industrial conditions and after long-term exposure to steam oxidation conditions in a thermal power plant. Both the effect of the grain size in austenite and the role of shot peening on steam oxidation are discussed.

Original languageEnglish
JournalMetallography, Microstructure, and Analysis
Volume9
Pages (from-to)603–614
ISSN2192-9262
DOIs
Publication statusPublished - 2020

Keywords

  • Annealing
  • Austenitic steel
  • Shot peening
  • Steamside oxidation
  • Superheater

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