HEAT TREATMENT OF 2 one quarter CR-1 MO STEEL FOR BREEDER REACTOR STEAM GENERATORS.

The mechanical properties of 2 one quarter Cr-1 Mo steel are determined by the microstructure, which can be different for annealed and normalized-and-tempered steel. The extreme in microstructural difference is when the normalized-and-tempered steel is entirely bainite and the anealled steel is 75 to 80% proeutectoid ferrite, the balance bainite. Mechanical property data for annealed and normalized-and-tempered 2 one quarter Cr-1- Mo steel with these microstructures were compared. The results were analyzed in terms of the kinetics of the different metallurgical changes that the various microstructures undergo during an elevated-temperature test or elevated-temperature exposure during service.