Effects of thermal aging on the low cycle fatigue of austenitic-ferritic duplex cast stainless steel behavior

Thermal aging is observed in a primary reactor cooling system (RCS) made of cast stainless steel. The observation occurs when the RCS is exposed for a long period of time to a reactor operating temperature between 290 and 330 degreesC. An investigation of the effect of thermal aging on the low cycle fatigue characteristics of CF8M is required. The purpose of the present in vestigation is to find the effect of thermal aging of CF8M on a low cycle f atigue life. The specimen of CF8M is prepared by an artificially accelerate d aging technique maintained for 300 and 1800 h at 4300 degreesC, respectiv ely. The low cycle fatigue tests for the virgin acid two aged specimens are performed at room temperature for the strain amplitudes (epsilon (ta)) of 0.3, 0.5, 0.8, 1.0, 1.2 and 1.5%. In the experiment, it is found that the f atigue life is rapidly reduces with an increase of aging time. The experime ntal fatigue life estimation formula, between the virgin and two aged speci mens are obtained. (C) 2001 Elsevier Science B.V. All rights reserved.