Radiation-embrittlement resistance of advanced NiCrMo steel plates, forgings, and weldments
The 550 deg F irradiation response characteristics of several NiCrMo steel plates, forgings, and weldments were evaluated. Primary objectives were to explore variable radiation-embrittlement tendencies and to assess notch ductility performance relative to that of the MnMoNi steel (ASTM Type A533-B) currently used in nuclear reactor vessel construction. The study was focused on ASTM Type A543 steel in Class 1 and Class 2 heat treatment conditions. Both submerged arc and electroslag weldments were evaluated. Irradiation embrittlement was indexed by the increase In Charpy-V 30 ft-lb transition temperature. Results clearly demonstrate the promise of ASTM Type X543 plate and related A508 forging steels for advanced reactor applications. Both radiation-embrittlement resistance and preirradiation transition temperature characteristics were found superior to those of standard production A533-B. With only two exceptions, the A543 plates and A503 forgings exhibited sufficient resistance to a fluence of 4 x 10/sup 19/ n/cm/sup 2/> 1 MeV to retain a subzero nil-ductility transition (NDT) temperature. Weld deposits generally had higher postirradiation transition temperatures than plates. The significant variability in radiation resistance noted among A543 plates and weld deposits could be traced in most instances to composition differences, especially residual element content differences. Anomalous weld heat-affected-zone (HAZ) behavior relative to weld thickness location was observed. A progressive increase in irradiation response with an increase in copper content was found. Vanadium content appears detrimental to radiation resistance of NiCrMo plates, but not to NiCrMo forgings. Weld deposit results infer a harmful effect of nickel content when chromium content is low. Notch ductility rccovery by postirradiation heat treatment was also explored. (auth)
- Research Organization:
- Naval Research Lab., Washington, D.C. (USA)
- NSA Number:
- NSA-29-008350
- OSTI ID:
- 4380746
- Report Number(s):
- NRL--7573
- Country of Publication:
- United States
- Language:
- English
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Significance of nickel and copper content to radiation sensitivity and postirradiation heat treatment recovery of reactor vessel steels
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Related Subjects
*STEEL-ASTM-A543-- PHYSICAL RADIATION EFFECTS
ELECTROSLAG WELDING
EMBRITTLEMENT
FAST NEUTRONS
FORGING
HIGH TEMPERATURE
N50240* --Metals
Ceramics
& Other Materials--Metals & Alloys--Radiation Effects
NEUTRON BEAMS
PLATES
PRESSURE VESSELS
SUBMERGED ARC WELDING
WELDED JOINTS STEEL-ASTM-A543