Shot peening

Hearst Mining building clad in stone on the left, with extension on the right covered in shot peened aluminum alloy

Shot peening is a cold working process used to produce a compressive residual stress layer and modify the mechanical properties of metals and composites. It entails striking a surface with shot (round metallic, glass, or ceramic particles) with force sufficient to create plastic deformation.[1][2]

In machining, shot peening is used to strengthen and relieve stress in components like steel automobile crankshafts and connecting rods. In architecture it provides a muted finish to metal. Shot peening is similar mechanically to sandblasting, though its purpose is not to remove material, but rather it employs the mechanism of plasticity to achieve its goal, with each particle functioning as a ball-peen hammer.

  1. ^ "Shot Peening," Tool and Manufacturing Engineers Handbook (TMEH), Volume 3, Society of Manufacturing Engineers, 1985
  2. ^ "Shot Peening Applications" (PDF) (10th ed.). Metal Improvement Company. 2020.