Shot Peening is primarily used to increase fatigue life by bombarding the surface of the part with small spheres of uniform media that induce compressive stresses. The Shotpeen Process is similar to repeatedly and evenly hammering a surface with a ball peen hammer.
Shot peening is used primarily to prevent fatigue failures that originate on the surface of a part. Small indentations or dimples form on the surface, and the metal immediately below those indentations tries to resist further compression, creating what’s known as residual compressive stress. Fatigue cracks generally will not initiate in a compressively stressed area, so part life is extended.
Shotpeening is different than Shot Blasting, which is a surface finishing technique that involves rapidly impacting the surface of an object with a controlled stream of abrasive material.