Technical note A study on stress, reflection and double shot peening to inrease compressive residual stress

Abstract

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).

Improvement of fatigue limit by shot peening for high‐strength steel containing a crack‐like surface defect

“…In general, increasing the hardness and the introduction of compressive residual stresses are effective methods for improving fatigue limits. While a hardness increase is known to increase the sensitivity of the material to defects, introducing compressive residual stresses by shot peening (SP) is widely used to improve the fatigue limits of vehicle parts (Suresh, 1991;Mitsubayashi et al, 1995;Ishigami et al, 2000;Webster et al, 2001;Guaglian et al, 2002;Lang et al, 2003).…”

Improving reliability of high‐strength steel designed against fatigue limit using surface crack nondamaging technology by shot peening

“…Residual stress ③ assumes that stress peening is performed as described in literature. 26,27 The stress range (Δσ w ) at the fatigue limit of a nonshot-peened smooth specimen (hereinafter, NonSP smooth specimen) was 840 MPa. The fatigue limit (Δσ s ) of the shot-peened smooth specimen (hereinafter, SP smooth specimen) was assumed to be 950 MPa.…”

The influence of partial surface shot peening on fatigue crack growth behaviour of a high‐strength ferritic steel

“…Mahmoudi et al studied the effect of initial compressive residual stress on subsequent compressive residual stress induced by shot peening and found that the initial residual stress was wiped out by shot peening up to the maximum compressive residual stress point. 14 Voorwald et al have investigated the effect of shot peening on rotating bending fatigue strength of chromium electroplated AISI 4340 steel for landing gear applications, and they found that the fatigue strength improved. 10 Takahashi et al investigated the effect of shot peening on the torsional fatigue limit in specimens containing artificial defects in highstrength steel specimens and found that the defect with specific dimensions could be rendered harmless by shot peening.…”

“…13 Ishigami et al have studied the influence of stress double shot peening and stress reflection double shot peening methods to quenched and tempered steel, and they found that the latter induced greater compressive residual stress at the outer surface of specimens. 14 Voorwald et al have investigated the effect of shot peening on rotating bending fatigue strength of chromium electroplated AISI 4340 steel for landing gear applications, and they found that the fatigue strength improved. They also showed that the peening process using ceramic shots resulted in lower scatter in rotating bending fatigue data than the steel shots.…”