scope:

Describes the requirements for automated, controlled shot-peening of metallic articles prior to electrolytic or autocatalytic deposition of nickel or chromium, or as a final finish, using shot made of cast steel, conditioned cut wire, ceramic shot or glass beads. The process is applicable to those materials on which test work has shown it to be beneficial within given intensity ranges. Shot-peening induces residual compressive stresses in the surface and near surface layers of metallic articles, and changes the surface microstructure (including phase transformation), thereby controlling or limiting the reduction in fatigue properties that occurs from nickel or chromium plating of the article, or increasing the fatigue properties of unplated articles.