Laser Peening has a unique ability to achieve deeper depths of compressive residual stress compared to shot peening. The high-energy impact from the laser shot at the surface of the part combined with precision control are part of what enables laser peening to reach depths in a component that are unrivaled. Our engineers have the ability to control the depth of magnitude of compressive residual stresses by increasing the power and coverage of the laser pulse. Laser peening can achieve compressive stress at a depth of 12mm depending on processing conditions, material, and geometry of the part.
Because laser peening uses less than 5% cold work, compressive residual stresses are also retained at much higher temperatures. Laser peening has an advantage for imparting compressive stress in parts that have hard-to-reach surfaces or complex geometries due to the optimization possible at precise locations on a part.
In the graph to the right, the shot peening (green and blue) curves show compressive residual stress values that quickly fall towards zero as depth increases. The laser peening (pink and orange) fall off more gradually and maintain compressive stress up to a milimeter beneath the surface.