Mean stress effect on fatigue life of 304L austenitic steel in air and PWR environments determined with strain and load controlled experiments

The mean stress effect on fatigue life of a 304L austenitic steel was evaluated at 300 °C in air and in pressurized water reactor (PWR) environment. Uniaxial tests were performed in strain-control and load-control modes with zero mean stress as well as with a positive mean stress of 50 MPa. A specific procedure was used for the strain-controlled experiments to maintain the strain amplitude and mean stress constant. The strain-controlled data indicate that the application of a positive mean stress decreases the fatigue life for a given strain amplitude in air and PWR environment. They also show that the life reduction is independent of the environments suggesting that no synergistic effects between mean stress and LWR environment occur. The load-controlled experiments confirm that the application of a positive mean stress increases the fatigue due to cyclic hardening processes. This observation is much less pronounced in PWR environment. All data were analyzed using the Smith-Watson-Topper (SWT) stress-strain function that was shown to correlate pretty well all strain- and load-controlled data with and without mean stress in each environment. In the SWT-life representation, the life reduction due PWR environment was found fully consistent with the NUREG-CR6909 predictions.

SPATIG Philiipe;  LE ROUX Jean-Christophe;  BRUCHHAUSEN Matthias;  MOTTERSHEAD Kevin; 

2021-01-29

MDPI

JRC122522

2075-4701 (online),   

https://www.mdpi.com/2075-4701/11/2/221,    https://publications.jrc.ec.europa.eu/repository/handle/JRC122522,   

10.3390/met11020221 (online),