Turbine blades in low pressure steam turbines are usually made of martensitic steels with a Cr concentration between 9 and 13%. Because of inhomogeneities within the flow field, blades are stressed by torsional and bending vibrations with a frequency > 1000 Hz. Due to the high useful life of the blades, loads are within the very high cycle fatigue (VHCF) range and are affected by mean loads that originate from the dead load and the rotation (mostly 50 Hz).

This project examined the fatigue behavior of steel X10CrNiMoV12-2-2 with the help of an ultrasonic testing system for different load ratios, and under the influence of notches in the material.