Predicting weld creep strength reduction for 9% Cr steels

Stefan Holmström (Corresponding Author), Pertti Auerkari

    Research output: Contribution to journalArticle in a proceedings journalScientificpeer-review

    11 Citations (Scopus)

    Abstract

    In design standards and in post-service life assessment, the cross-weld (CW) creep strength of ferritic steels is nearly universally assumed to be 80% of the corresponding value for the parent material (PH). However, CW data assessment of some 9% Cr steels such as E911 and P91 suggests that this would not hold at least at the high temperature end of the testing range. The resulting weld creep strength factor (WSF) is then attaining values well below 0.8 when extrapolated to typical design life of 100 000 h or more. Under such conditions the conventional value of 0.8 would result in non-conservative (too long) predicted life for structures subjected to CW loading in the creep regime.

    To accommodate the CW strength data for realistic values of WSF requires appropriate correction based on actual data. For this purpose, an alternative assessment approach, rigidity parameter correction (RPC), is proposed. This approach can be used to predict CW rupture strength from the PM master curves, with any PM rupture model optimized to correspond to the welded materials data.
    Original languageEnglish
    Pages (from-to)803-808
    Number of pages6
    JournalInternational Journal of Pressure Vessels and Piping
    Volume83
    Issue number11-12
    DOIs
    Publication statusPublished - 2006
    MoE publication typeA4 Article in a conference publication
    EventInternational Conference WELDS 2005: Design, Testing, Assessment and Safety of High Temperature Welded Structures - Geesthacht, Germany
    Duration: 8 Aug 20059 Aug 2005

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    Keywords

    • creep
    • welds
    • modeling
    • extrapolation
    • 9% Cr
    • ferritic steel
    • ECCC

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