Effect of selective dissolution on stress corrosion cracking susceptibility of austenitic and duplex stainless steels in alkaline solutions

Heikki Leinonen, Pekka Pohjanne, Tapio Saukkonen, Tanja Schildt, Jyrki Romu, Hannu Hänninen

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    Abstract

    The formation of nickel-rich layers on austenitic stainless steels in strong caustic solutions was reported in 1970's.
    Recently, a more detailed study has shown the nature of the de-alloying process and established firm links with the other metal-environment systems that show de-alloying and associated stress corrosion cracking (SCC) in strong caustic environments. In this study, the role of de-alloying in SCC of the austenitic and duplex stainless steel AISI 304 (EN1.4301) and S322205 (EN1.4462) is evaluated in 50% NaOH and also in NaCl/Na2S containing caustic environments (pulping liquors) at 413 K (140ºC) and 463 K (190ºC).
    The results show that selective dissolution of alloying elements occurs on surface of the specimens and at the crack tip and strain is necessary for selective dissolution. The proposal that the rate determining step in SCC is generation of vacancies by selective dissolution at the crack tip will be confirmed in the further detailed examinations.
    Chromium, iron and molybdenum are dissolving selectively and/or precipitating during the process which affects the general corrosion and SCC susceptibility depending on the alloy composition and microstructure of the steel.
    FEG-SEM examination shows that the de-alloyed layer exhibits extremely fine nanoporosity.
    Original languageEnglish
    Title of host publicationProceedings
    Subtitle of host publicationCorrosion 2011, Conference & Expo
    Place of PublicationHouston, TX
    Number of pages17
    Volume2
    Publication statusPublished - 2011
    MoE publication typeA4 Article in a conference publication
    EventCorrosion 2011, Conference & Expo  - Houston, TX, United States
    Duration: 13 Mar 201117 Mar 2011

    Conference

    ConferenceCorrosion 2011, Conference & Expo 
    CountryUnited States
    CityHouston, TX
    Period13/03/1117/03/11

    Keywords

    • selective dissolution
    • de-alloying
    • duplex stainless steel
    • austenitic stainless steel
    • stress corrosion cracking
    • caustic solution

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  • Cite this

    Leinonen, H., Pohjanne, P., Saukkonen, T., Schildt, T., Romu, J., & Hänninen, H. (2011). Effect of selective dissolution on stress corrosion cracking susceptibility of austenitic and duplex stainless steels in alkaline solutions. In Proceedings: Corrosion 2011, Conference & Expo (Vol. 2). [11160]. https://www.onepetro.org/conference-paper/NACE-11160