Effect of microstructure on KCl corrosion attack of modified AISI 310 steel

Yohanes Chekol Malede*, Melanie Montgomery, Kristian Vinter Dahl, John Hald

*Corresponding author for this work

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Abstract

The effect of microstructure on KCl corrosion attack was studied using a specifically chosen modified AISI 310 austenitic steel in a 15% (v/v) H2O (g)+ 5%(v/v) O2 (g) + N2 (g) (balance) atmosphere at 600°C for 168 h. The material was a targeted choice as it allows investigation of different microstructures i.e. as-received (without sigma phase) and heat-treated (29% σ-phase per area) microstructures. The corrosion attack was studied with light optical, scanning electron and transmission electron microscopy as well as X-ray diffraction. The heat-treated sample showed a corrosion attack that was 5 times higher than the as-received sample. In the heat-treated sample, the σ-phase was selectively attacked. At the corrosion front, chlorine (but not potassium) was detected in the selectively attacked σ- phase but not in the unattacked adjacent matrix. Therefore, the corrosion attack was propagated by preferential σ-phase attack by chlorine species.
Original languageEnglish
JournalMaterials at High Temperatures
Volume35
Issue number1-3
Pages (from-to)243-254
ISSN0960-3409
DOIs
Publication statusPublished - 2018

Keywords

  • Internal corrosion
  • Effect of microstructure
  • KCl corrosion
  • Modified 310 steel
  • High temperature corrosion
  • Sigma-phase

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