Experimental Study on Elevated Temperature Low Cycle Fatigue of P92 Steel

A supercritical water cooled reactor (SCWR) is being considered as a candidate reactor of the Generation Ⅳ nuclear reactors due to its high thermal efficiency and simple system composition. A critical question to attain is to choose proper materials for the core components, especially for the fuel cladding. The mechanic properties, corrosion and stress corrosion cracking susceptibilities, radiation resistances, etc., of these materials at high temperature are extremely important for the safety of nuclear power plant. The paper presents the low cycle fatigue behaviors of P92, a kind of F/M type candidate materials for the SCWR. The experiments were carried out at 600 ℃ and 650 ℃ with total strain controlled. The strain range is from ±0.2%±0.6%, respectively. The results show that P92 steel is cyclic strain softening at both temperatures, but stable cyclic phenomena were not observed. The decline ratio of macro-crack appearance with the strain range increasing is milder at 650 ℃ than that at 600 ℃, and the cycles to failure are remarkably higher at 650 ℃ than those at 600 ℃ under the same total strain ranges. The relationship of cycle stable stress vs. strain range and number of cycles to failure vs. total strain range were obtained.