Decrease of surface compressive residual stresses in an perfectly induction hardened and tempered steel S45C was confirmed to be small during rotating bending fatigue process. Before fatigue, the surface compcessive residual stress firstly relaxed in room temperature for about 5 years, and secondly relaxed in 80℃ for about 35 months or 120℃ for about 83 days, after that, relaxed by 200℃ tempering.
