Fatigue behavior of austenitic materials considering the exposure time

The ASME Code Section III includes a new design curve (air/room temperature) for all austenitic materials. In the contribution the fatigue behavior of the Nb stabilized austenitic materials 1.4550 (XCrNiNb1810 mod) is presented. Supplementary experiments have shown that qualitatively comparable results are reached with other stabilizing additives (Ti). Questions concerning the transferability of experimental laboratory results on reactor components under realistic load conditions (for instance exposure time at increased temperature) are discussed. The ASME design curve is shown to be very conservative. The evaluation of experimental results indicates a significant higher lifetime prognosis for the steel 1.4550 despite the fact that exposure times were considered.