Shot peening is a process specifically designed to enhance the fatigue strength of components which are subject to high alternating stress. Surface treatment procedures like grinding, milling, bending or heat treatment procedures cause Tensile Residual Stress. This Tensile Residual Stress leads to low life cycles of the parts. Shot Peening converts Tensile Residual Stress into Compressive Residual Stress which leads to significant increases in the life cycle of parts and their maximum load capacities.
Shot Peening is cost effective and reliable and can be achieved with Air blasting or Wheel blasting– depending on capacities, part size and requirements. Landing gears or turbine blades of aircraft, gear wheels, gear shafts, valve springs, suspension springs, connecting rods, and many other parts in various industries are shot peened every day.
The Mechanics of Shot Peening
What is shot peening?
Shot peening is a cold working process used to produce a compressive residual stress layer and modify the mechanical properties of metals. It entails impacting a surface with shot (round metallic, glass, or ceramic particles) with a force sufficient to create plastic deformation. Peening a surface spreads it plastically, causing changes in the mechanical properties of the surface. The main benefit of shot peening is the delay or prevention of cracks in highly tensile stressed alloy components.
We can alter these undesirable manufacturing and operational tensile stresses to life enhancing residual compressive stresses therefore extending component life. The process works by introducing the residual compressive stress in the surface of the component. The compressive stress helps to prevent crack initiation as cracks cannot propagate in the compressive environment generated by peening.