Simulation of multiaxial fatigue strength of steel component treated by surface induction hardening and comparison with experimental results

This paper proposes a method to assess the high-cycle multiaxial fatigue strength of components treated by surface induction hardening (SIH). Surface quenching following surface induction heating is simulated, taking into account the following features of the process: (i) electromagnetic and thermal fields, (ii) phase transformation, and (iii) the residual stress field resulting from the entire process. The fatigue strength of the specimens was simulated using Crossland and Dang-Van criteria; the field of the residual stresses and the fatigue characteristics of both the untreated material and the treated layer (martensite) are considered. Fatigue tests on smooth specimens were carried out to compare simulated results with experimental data. These tests yield information regarding the influence of the thermal treatment on material behaviour and strength, including microstructure evolution and mechanical characteristics, especially in fatigue. For this purpose, residual stresses were analyzed by X-ray diffraction before and after the fatigue tests. Fatigue crack initiation areas (at the specimen’s surface or below) are predicted depending on the depth of the hardened material layer. The simulation of the fatigue strength at 2 × 106 cycles is in good agreement with experimental results.