Study of the effects produced by shot peening on the surface of quenched and tempered steels: roughness, residual stresses and work hardening

Abstract Shot peening induces important effects on the surface of materials, both positive and negative, the correct balance between them being the key to success. Roughness, impact mark size, compressive residual stress and work hardening of six steel grades obtained from an AISI 4340 steel were studied to explain their evolution according to the Almen intensity and their mechanical properties. A linear relationship between the impact diameter, the kinetic energy of the balls and the Almen intensity was found. Moreover, under full coverage, the surface and the maximum compressive stresses only depend on the mechanical properties of the steels, whereas the depth subjected to high compressive residual stresses and the total depth subjected to compressive residual stresses depend on the mechanical properties of the steel and the Almen intensity. Furthermore, several mathematic expressions were formulated to predict the residual stress profiles using the Almen intensity and the mechanical properties of the steels.