The technique of shot peening is commonly used to increase the fatigue limit of a steel. However, there are many practical difficulties in applying it to very high HV steel and complicated components. To overcome these problems, the authors proposed two new methods: stress double shot peening and stress reflection double shot peening. Both techniques were applied to quench and tempered steel (QT steel) and induction‐heated steel (IH steel). The main results were as follows: (a) by double shot peening, the compressive residual stress near the sample surface was increased considerably; (b) by stress shot peening, the maximum compressive residual stress (σmax ) and the surface compressive residual stress (σs ) were greatly increased; (c) by stress double shot peening, very high compressive residual stresses (σmax = −1710 MPa and σs = −1320 MPa) were successfully introduced into a hard steel (HV = 700); (d) in the new method (stress reflection double shot peening), very high compressive residual stresses (σmax = −1760 MPa and σs = −1460 MPa) were successfully introduced into a hard steel (HV = 700).

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