Specimen geometry effect on creep crack growth in 316L(N)

International audienceThe ASTM E1457-98 standard describes the procedure to determine the master curve da/dt versus C* parameter, for creeping solids. However, the methodology is only to be applied to compact tension (CT) specimens. The European collaborative program CRETE aims at extending the application of the ASTM E1457-98 standard to other types of laboratory specimens. In this paper, an existing database of creep crack growth on 316L(N) stainless steel is utilized, concerning three types of specimens: circumferentially cracked round bars (CCRBs) and double edge notched tensile (DENT) specimens for tensile mechanical loading whereas the classical CT specimen combines tensile and bending loading modes. A modified procedure based on the ASTM E1457-98 standard has been applied to the database, resulting in a unique master curve of da/dt versus C*. The geometry effect is then investigated by introducing the Q* parameter by analogy to the Q parameter in the elastic–plastic J-Q approach