High-Temperature Degradation and Protection of Ferritic and Austenitic Steels in Steam Generators

A. Martínez-Villafañe*, M. F. Almeraya-Calderón*, C. Gaona-Tiburcio*, J. G. Gonzalez-Rodriguez*, J. Porcayo-Calderón*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The useful life of superheaters and reheaters of power stations which use heavy fuel oil is shortened and their continuous service is inhibited by corrosion (fireside) and creep-type problems. The increase of corrosionattack on boilers is caused by the presence of fuel ash deposits containing mainly vanadium, sodium,and sulfur which form low-melting-point compounds. The tubes are exposed to the action of highstresses and high temperatures, producing the so-called “creep damage.” In this work, two kinds of resultsare reported: lab and field studies using a 2.25Cr-1Mo steel. The laboratory work was in turn dividedinto two parts. In the first, the steel was exposed to the action of natural ash deposits in oxidantatmospheres at 600 °C for 24 h. In the second part, tensile specimens were creep tested in Na2SO4, V2O5,and their mixture over a temperature range of 580 to 620 °C. In the field work, components of a powerstation were coated with different types of nickel- and iron-base coatings containing chromium, Fe-Cr,and Fe-Si using the powder flame spraying technique. After testing, the coated tubes were analyzed usingelectron microscopy. The results showed that all the coating systems had good corrosion resistance, especiallythose containing silicon or chromium.

Original languageEnglish
Pages (from-to)108-113
Number of pages6
JournalJournal of Materials Engineering and Performance
Volume7
Issue number1
DOIs
StatePublished - Feb 1997
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 1997, ASM International.

Keywords

  • Alkali Metal Sulfate
  • Austenitic Stainless Steel
  • EPRI Report
  • Fireside Corrosion
  • Vanadium Pentoxide

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