As macroscopic imperfections can be locally treated as notches, it is advisable to use
established notch fatigue concepts to deduce the service strength of defect-afflicted cast steel
alloys. Recently, an advanced local fatigue assessment method has been developed within
the CD-Laboratory for ‘Manufacturing Process based Component Design’ at the Chair of
Mechanical Engineering, Montanuniversität Leoben. This design procedure bases on the
“Total Strain Energy Density” method (T-SED) and features a probabilistic assessment of
planar defect projections. The method has been validated for large-scale, defect afflicted,
specimens under constant amplitude loading. This contribution addresses the operational
strength as variable amplitude loading for cast steel G12MnMo7-4+QT. In total, forty variable
amplitude load tests were carried out covering block-load sequences as well as service-load
signals from railway bogie measurements. It is demonstrated that the T-SED method is well
applicable to calculate the service strength of cast steel samples under variable, uniaxial
loading for varying bulk defect geometries. A damage sum of D = 0.3 is recommendable to
meet the design limit curve of the investigated high-strength cast steel alloy.