Investigation of the fatigue behavior of austenitic stainless steels and their welds for reactor internals under very high cycle (VHCF) operational loading conditions

The general aim of this project is to investigate and evaluate the fatigue behaviour of austenitic steel and its welded connections at service-relevant operating temperatures for reactor pressure vessels in air environments up to very high load cycles.  For this, load-controlled fatigue tests will be carried out in an ultrasonic test system with a frequency of 20 kHz at room temperature as well as elevated temperature (T = 300 °C) up to  the limiting number of cycles (Nl = 2·109). We will examine microstructual changes resulting from the cyclic stress by light and electron-microscopy as well as X-ray methods.

The project is carried out in collaboration with Materialprüfungsanstalt Universität Stuttgart and Framatome GmbH, and supported by the Federal Ministry for Economic Affairs and Energy.

Publications

Daniel T., Smaga M., et al.: Investigation of the very high cycle fatigue (VHCF) behavior of austenitic stainless steels and their welds for
reactor internals at ambient temperature and 300 °C. Proc. ASME PVP Conf. 2020:PVP2020-21460, DOI

Daniel T., Smaga M., Beck T.: Ermüdungsverhalten des metastabilen austenitischen Stahls AISI 347 bei Raumtemperatur und 300 °C im
VHCF-Bereich, Tagungsband Werkstoffprüfung 2019:81–6

Daniel T., Smaga M., Beck T.: Cyclic deformation behavior of metastable austenitic stainless steel AISI 347 in the VHCF regime at ambient
temperature and 300 °C, Int. J. Fatigue 156, 2021, DOI