STP683: Exploratory Investigations of Cyclic Irradiation and Annealing Effects on Notch Ductility of A533-B Weld Deposits

    Hawthorne, JR
    Research metallurgist and supervisory mechanical engineers, Naval Research Laboratory, Washington, D.C.

    Watson, HE
    Research metallurgist and supervisory mechanical engineers, Naval Research Laboratory, Washington, D.C.

    Loss, FJ
    Research metallurgist and supervisory mechanical engineers, Naval Research Laboratory, Washington, D.C.

    Pages: 17    Published: Jan 1979


    Abstract

    Postirradiation heat treatment (annealing) is being investigated as a possible method for the periodic relief of radiation embrittlement to reactor vessel steels. This report describes a study of the Charpy-V (CV) notch ductility of two representative A533-B weld deposits under two full annealing and reirradiation cycles. The welds were specially chosen for their high sensitivity to radiation effects and for their difference in as-fabricated CV upper-shelf energy levels. Notch ductility properties were determined at each phase in the irradiation-annealing sequence. Heat-treatment temperatures were selected to represent two heat-treatment options open for vessel annealing.

    The results demonstrate that a 399°C (750°F), 168-h heat treatment is highly effective for reducing radiation embrittlement accrual in service; in contrast, a 343°C (650°F), 168-h heat treatment is shown to be of little benefit for the fluence conditions investigated. A greater rate of radiation embrittlement was observed for the heat-treated material (both conditions) compared with nonheat-treated material. The investigations also revealed a significant difference between upper-shelf energy and transition temperature response to heat treatment.

    Keywords:

    radiation effects, notch ductility, embrittlement relief, weldments, pressure vessel steel, low-alloy steel, steels, postirradiation heat treatment, annealing


    Paper ID: STP38171S

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP38171S


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