THERMAL FATIGUE BEHAVIOR FOR A 316-L-TYPE STEEL

This paper deals with initiation and growth of cracks produced by ther mal fatigue loadings on 316 L steel, which is a reference material for the first wall of the next fusion reactor ITER. Two types of faciliti es have been built. As for true components, thermal cycles have been r epeatedly applied on the surface of the specimen, The first is mainly concerned with initiation, which is detected with a light microscope. The second allows one to determine the propagation of a single crack. Crack initiation is analyzed using the French RCC-MR code procedure, a nd the strain-controlled isothermal fatigue curves. To predict crack g rowth, a model previously proposed by Haigh and Skelton is applied. Th is is based on determination of effective stress intensity factors, wh ich takes into account both plastic strain and crack closure phenomena . It is shown that estimations obtained with such methodologies are in good agreement with experimental data.