Effects of water chemistry transients on crack growth rate of nickel-based weld metals

Aki Toivonen, Pekka Moilanen, Pertti Aaltonen, Laura Taivalaho, Erkki Muttilainen

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

    2 Citations (Scopus)

    Abstract

    Stress corrosion crack growth rates of Alloy 182 and 82 weld metals in thermally aged (400°C/200 h) conditions have been measured in simulated BWR conditions. The effects of water chemistry impurity concentration transients on crack growth rate and cracking morphology have been studied. The time for onset of accelerated crack growth due to impurity / conductivity transient was measured when the conductivity of the coolant was adjusted by additions of sulphate as H2SO4 in the range of 10-100 ppb. Crack growth was monitored using potential drop method during slow rising displacement testing applied to 10x10 mm2 cross section, fatigue pre-cracked, three point bend specimens. The delay in crack growth rate slow down after returning to high purity water was also measured. In the tests an increase in the crack growth rate became visible in Alloy 182 within 25-45 h after sulphate was introduced into the bulk water. Although there is no reason or consistent data to support a permanent increase in crack growth rate caused by a sulphate transient, the measured crack growth rate did not return back to the level prevailing prior to the transient. In Alloy 82 no crack growth was observed with any of the applied conditions of this study. Crack growth rates were measured also for cold deformed AISI 316NG and furnace sensitised AISI 304 stainless steels, as reference.
    Original languageEnglish
    Title of host publication Plant Life Management
    Subtitle of host publicationProgress for structural integrity
    Place of PublicationEspoo
    PublisherVTT Technical Research Centre of Finland
    Pages223-239
    ISBN (Electronic)951-38-6281-X
    ISBN (Print)951-38-6280-1
    Publication statusPublished - 2003
    MoE publication typeB3 Non-refereed article in conference proceedings
    EventPlant Life Management: Progress for structural integrity - Espoo, Finland
    Duration: 1 Jan 20021 Jan 2002

    Publication series

    SeriesVTT Symposium
    Number227
    ISSN0357-9387

    Seminar

    SeminarPlant Life Management
    CountryFinland
    CityEspoo
    Period1/01/021/01/02

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  • Cite this

    Toivonen, A., Moilanen, P., Aaltonen, P., Taivalaho, L., & Muttilainen, E. (2003). Effects of water chemistry transients on crack growth rate of nickel-based weld metals. In Plant Life Management: Progress for structural integrity (pp. 223-239). VTT Technical Research Centre of Finland. VTT Symposium, No. 227 http://www.vtt.fi/inf/pdf/symposiums/2003/S227.pdf