Evaluation of Thermal-Aged Plates, Forgings, and Submerged-Arc Weld Metals

Abstract

Thermal-aged surveillance material was removed from two commercial reactor pressure vessels. The material from the first reactor vessel received a thermal exposure of approximately 103,000 hours at 282°C (540°F), while the material from the second reactor vessel received a thermal exposure of approximately 93,000 hours at 282°C (540°F). The surveillance material removed consisted of SA-508, Class 2 and SA-533, Grade B, Class 1, base metals; Mn-Mo-Ni/Linde 80 flux weld metals; and SA-533, Grade B, Class 1, correlation monitor material. Charpy V-notch impact specimens were fabricated from these materials and tested. In addition, selected thermal-aged specimens were annealed at 343°C (650°F) and 454°C (850°F) and impact tested. Unaged material was tested to establish baseline data for evaluating the thermal-aged material and thermal-aged/annealed material. Small variations in the impact properties were observed for all materials. Small increases in transition temperature were observed for the forging base metal and weld metal B surveillance materials, while the upper-shelf energies exhibited small decreases. The 454°C (850°F) anneal restored the upper-shelf energy for the forging base metal and weld metal B surveillance materials.