Creep-fatigue crack growth in austenitic stainless steel centre cracked plates at 650°C. Part I: experimental study and interpretation

Experimental data on fatigue or creep-fatigue crack growth on large components at high temperature are of primary importance to validate or develop further existing defect assessment procedures and leak before break methods. This paper addresses in the first part a detailed presentation of a creep-fatigue experiment consisting of a wide plate subjected to cyclic bending loads. The specimen consists of a large 316L(N) austenitic stainless steel plate containing a wide semi-elliptical surface notch, machined in the centre of the specimen. The test is conducted at a temperature of 650°C. Over 3000 cycles with a one hour holdtime at the peak load of the cycle were applied to the plate allowing to obtain a significant amount of crack growth, both on the surface and through the thickness of the plate. In the second part, a first interpretation of the experimental results is proposed. It is based on global fracture mechanics quantities estimated from a linear elastic analysis. The results are compared with those...