The paper contains the results of fatigue tests of 10HNAP steel under nonproportional
bending with torsion. The circular smooth specimens were tested. The tests were
carried out at the fatigue test stands MZGS-200PL and MZGS-200L. The best results of
experimental and calculation lives consistence for the considered materials was obtained
using the criterion of maximum shear stresses in the critical plane and the Palmgren-Miner
hypothesis of damage accumulation