INITIAL ASSESSMENTS OF NOTCH DUCTILITY BEHAVIOR OF A533 PRESSURE VESSEL STEEL WITH NEUTRON IRRADIATION.

Exploratory assessments were made of the Charpy-V notch ductility characteristics of heavy section A533-B and A533-C steel plate and submerged arc weldments following neutron irradiation at 550F. The experimental evaluations were performed largely with commercial production materials and included comparisons of materials in both Class 1 and Class 2 strength ranges. Postirradiation notch ductility properties of one 5-34-in. A533-B Class 1 electroslag weldment were also developed. Assessments made of relative irradiation performance were assisted by a compilation of recent information on the response of the ASTM reference A302-B steel plate. Major research findings include the observation of significant variability in radiation embrittlement sensitivity of A533-B and A533-C steel wherein the sensitivity level of plate and weld metal in some cases exceeded that of the ASTM reference plate. High radiation embrittlement sensitivity was noted for both submerged arc weld deposits examined however, the data suggest that the performance of the weld-heat-affected zone parallels that of the parent plate. High embrittlement sensitivity was also noted for the electroslag weld deposit, in contrast to markedly low sensitivity of the weldment parent plate. The notch ductility behavior of A533 plate and weld metal under 550F irradiation was not found to be measurably influenced by either the strength class Class 1 or 2 or by the particular grade of steel Grade B or C. Similarly, there were no marked variations in irradiation response through the thickness of plate or weld metals, or between RW longitudinal versus WR Transverse orientations in cross-rolled plate. Author