What is shot peening?

Shot peening is a cold working process, used to produce a compressive residual stress layer and modify mechanical properties of metals and composites. It entails impacting a surface with shot (by round metallic, glass, or ceramic particles) with force sufficient to create plastic deformation.

In machining, shot peening is used to strengthen the surface and relieve stress in components like steel automobile crankshafts and connecting rods. It also provides a muted finish to bright metal surface for cosmetic effect.

Shot peening is similar to sandblasting, except that it operates by the mechanism of plasticity rather than abrasion: each particle functions as a ball-peen hammer. In practice, this means that less material is removed by the process, and less dust created.