Predicting weld creep strength reduction for 9% Cr steels

Stefan Holmström (Corresponding Author), Pertti Auerkari

    Research output: Contribution to journalArticleScientificpeer-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 typeA1 Journal article-refereed

    Fingerprint

    Steel
    Creep
    Welds
    Ferritic steel
    Service life
    Rigidity
    Testing

    Keywords

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

    Cite this

    @article{4fedec12a9c94b24a87ace2175e396c2,
    title = "Predicting weld creep strength reduction for 9{\%} Cr steels",
    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.",
    keywords = "creep, welds, modeling, extrapolation, 9{\%} Cr, ferritic steel, ECCC",
    author = "Stefan Holmstr{\"o}m and Pertti Auerkari",
    year = "2006",
    doi = "10.1016/j.ijpvp.2006.08.007",
    language = "English",
    volume = "83",
    pages = "803--808",
    journal = "International Journal of Pressure Vessels and Piping",
    issn = "0308-0161",
    publisher = "Elsevier",
    number = "11-12",

    }

    Predicting weld creep strength reduction for 9% Cr steels. / Holmström, Stefan (Corresponding Author); Auerkari, Pertti.

    In: International Journal of Pressure Vessels and Piping, Vol. 83, No. 11-12, 2006, p. 803-808.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Predicting weld creep strength reduction for 9% Cr steels

    AU - Holmström, Stefan

    AU - Auerkari, Pertti

    PY - 2006

    Y1 - 2006

    N2 - 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.

    AB - 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.

    KW - creep

    KW - welds

    KW - modeling

    KW - extrapolation

    KW - 9% Cr

    KW - ferritic steel

    KW - ECCC

    U2 - 10.1016/j.ijpvp.2006.08.007

    DO - 10.1016/j.ijpvp.2006.08.007

    M3 - Article

    VL - 83

    SP - 803

    EP - 808

    JO - International Journal of Pressure Vessels and Piping

    JF - International Journal of Pressure Vessels and Piping

    SN - 0308-0161

    IS - 11-12

    ER -