Creep damage and long term life of steam line components: Case X20

Stefan Holmström, Pertti Auerkari, Jorma Salonen, Anssi Laukkanen, Juhani Rantala, Reino Nikkarila, Jarmo Junttanen

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

    Abstract

    Hot steam lines operate at high temperatures and are designed against creep. In service they will consume the creep life at the highest rate in locations with the most adverse combination of material strength (weakness) and high stress (e.g. system loads). Adverse effects in stress state are promoted by features of geometry and discontinuities in the materials properties. In practice it is essential to find the areas of maximum damage, as these will determine the locations and timing to inspect and finally to repair or replace before failures or unplanned outages. The inspection experience from power plant steam systems have provided the established views on the expected locations of the early creep damage, and rules on timing the next inspection. The experience has also shown that optimal timing is materials dependent, and that the steel grade X20CrMoV11-1 (X20, 11% Cr steel) performs particularly well in the inspection statistics. This paper describes a case with observed creep cavitation and cracking in a branch weld of a X20 steam header that was replaced after 135 000 service hours. The characteristics of the observed damage and its evolution are discussed.
    Original languageEnglish
    Title of host publicationBaltica VIII
    Subtitle of host publicationLife Management and Maintenance for Power Plants
    Place of PublicationEspoo
    PublisherVTT Technical Research Centre of Finland
    Pages154-166
    Volume2
    ISBN (Electronic)978-951-38-7594-7
    ISBN (Print)978-951-38-7593-2
    Publication statusPublished - 2010
    MoE publication typeB3 Non-refereed article in conference proceedings
    EventBALTICA VIII - International Conference on Life Management and Maintenance for Power Plants - Helsinki-Stockholm, Finland
    Duration: 18 May 201020 May 2010

    Publication series

    SeriesVTT Symposium
    Number265
    ISSN0357-9387

    Conference

    ConferenceBALTICA VIII - International Conference on Life Management and Maintenance for Power Plants
    CountryFinland
    CityHelsinki-Stockholm
    Period18/05/1020/05/10

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  • Cite this

    Holmström, S., Auerkari, P., Salonen, J., Laukkanen, A., Rantala, J., Nikkarila, R., & Junttanen, J. (2010). Creep damage and long term life of steam line components: Case X20. In Baltica VIII: Life Management and Maintenance for Power Plants (Vol. 2, pp. 154-166). VTT Technical Research Centre of Finland. VTT Symposium, No. 265 https://www.vtt.fi/inf/pdf/symposiums/2011/S265.pdf