Fatigue behaviour of 16Mo3 steel at elevated temperatures under uniaxial as well as biaxial-planar loading

The isothermal fatigue behaviour of the ferritic steel 16Mo3 was investigated at 200 and 500 degrees C under uniaxial and biaxial-planar loading. Furthermore, thermo-mechanical fatigue behaviour under uniaxial loading was characterized under in-phase (IP) and out-of-phase (OP) conditions between 200 and 500 degrees C. The fatigue lives of uniaxial and biaxial loading are in a good agreement to each other by using the distortion energy hypothesis according to von Mises. Under IP and OP thermo-mechanical loading, nearly the same lifetimes were determined. They agree well with those of the isothermal tests at 500 degrees C. A recently developed fatigue lifetime model was applied on all tests and shows an excellent agreement within a scatter of two.