SEDL / STP / STP725-EB / STP28206S

Experimental Investigation of Multicycle Irradiation and Annealing Effects on Notch Ductility of A533-B Weld Deposits

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

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

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

Pages: 13    Published: Jan 1981

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Abstract

Postirradiation heat treatment (annealing) at 399°C has demonstrated a capability for the relief of radiation embrittlement to reactor vessel steels. Building on an earlier investigation, this report describes a study of Charpy-V (CV) notch ductility and tensile properties behavior of two representative reactor vessel welds under cyclic 399°C postirradiation annealing and 288°C reirradiation. The welds were by the submerged-arc process and were chosen for their high radiation sensitivity (high copper content) and for their difference in as-fabricated CV upper-shelf energy levels derived from different welding fluxes. Weld properties were determined at each phase of the anneal-reirradiation-reanneal-reirradiation sequence.

The study clearly demonstrates the capability of the annealing method for maintaining property changes for reactor steels, including CV upper-shelf reduction and transition temperature elevation, below prefixed limits. In addition, the study confirms a significantly greater rate of embrittlement by heat-treated material compared with nonheat-treated material. Pronounced dissimilarities between CV upper-shelf energy and transition temperature behavior were observed, but parallels were shown with tensile ductility and strength changes, respectively, during annealing and reirradiation.