Depletion zones and intergranular corrosion of superaustenitic stainless steel Alloy 926

G. Mori*, M. Prohaska, R. Lackner, K. Rokosz, M. Albu, G. Kothleitner

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Superaustenitic stainless steel Alloy 926 was evaluated after different isothermal annealing and thermomechanical heat treatments. The impact of two different quenching and tempering processes on sensitization was determined. Since Alloy 926 contains large amounts of molybdenum and chromium, precipitation of various intermetallic phases is strongly favored. Based on SEM and EF-TEM, it was found that the size as well as the extent of elemental depletion zones is in good agreement with the degree of sensitization (DOS), independently of the applied corrosion test. Elemental depletion zones of two isothermally annealed conditions were obtained quantitatively and related to those of thermo-mechanically rolled samples. Comparison of both annealed conditions revealed the different operating principles of Streicher test and DL-EPR-test. In consequence, morphology, distribution, and chemical composition of precipitates have a considerable impact on corrosion test results. Different microstructural parameters and their relevance on prediction of corrosion properties are pointed out and discussed accurately.

Original languageEnglish
Pages (from-to)284-294
Number of pages11
JournalMaterials and Corrosion
Volume68
Issue number3
DOIs
Publication statusPublished - 1 Mar 2017

Keywords

  • Alloy 926
  • depletion zone
  • EPR test
  • intergranular corrosion
  • sensitization

ASJC Scopus subject areas

  • Environmental Chemistry
  • Mechanics of Materials
  • Mechanical Engineering
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

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