What is Shot Peening?

Shot peening is a cold working metal treatment process used to improve the fatigue life of a part. It substantially increases the fatique strength as well as increasing the resistance of stress, corrosion and wear. It also improves surface finish and coating adhesion. The presence of this surface compressive force serves to impede the start and growth of fatique cracks.

How is Shot Peening Done?

In the shot peening process, thousands of tiny uniformly sized spherical steel balls (shots) are propeled against the part at high energy. Each shot striking the part acts as a tiny peening hammer which creates small indentations or dimples on the surface. The outcome of this process is a uniformly dimpled surface; the roughness being determined by the shot size and peening force. This results in a stressed surface layer that serves as a deterrent to fatique cracks. Peening is capable of producing uniform results on a consistent basis and the process is non-abrasive.

How Does Shot Peening Work?

Shot peening is a surface treatment process, and most fatique failures are generated from stress raised at the surface. The fatique failures emerge from various sources and result in concentrations of residual surface stresses. Shot peening counteracts residual surface tensile stresses by the introduction fo compressive stresses. This creates numerous improvements and some are detailed below.

What are the Improvements from Shot Peening?

The most significant and obvious improvement will be that shot peening will prevent fatique failures in metal parts thereby allowing the part to function under greater stress levels. For example, a spring's life will be increased 400% to 1000% depending on the extent of peening already imparted on the spring. Gear life will increase up to 500% and drive pinions display a 40% to 414% life increase with peening. These are just a few of the improvements. Contact Metal Preparations and see how we can improve the productivity of your company.