Shot Peening – What Is It and How Does It Work?

October 14, 2015

Shot peening in its earliest form was known as mechanical prestressing or cold hammering. It is a process for increasing the life, strength and performance of metal parts, but why and how?

What does Shot Peening Do?

Controlled shot peening creates an area of compressive stress which is resistant to fatigue and stress corrosion cracking. The compressive stress replaces any residual stresses that may have been introduced during manufacturing and by external applied stresses such as bending load, torsional load and pressure load. If shot peening is introduced as part of the manufacturing process, significant improvements in life and performance can be realised. Fatigue resulting from residual and applied stresses, together with stress corrosion is reduced by shot peening.

Shot peening is a cost effective treatment which can be performed on components of any shape and size and also on-site for large or fixed equipment. When combined with reduced maintenance costs achieved by extended part life, you can clearly see why leading manufacturers include this process in their specifications.

What is the process of Shot Peening?

Shot peening is still a cold working process where small spherical media called shot strikes the surface creating a small indentation. In order for the indentation to appear the surface layer must yield in tension. However, the compressed material grains try to restore the original shape which produces an area of compression. Continual coverage forms a uniform layer of residual compressive stress. Cracks will not occur in a compressively stressed area. For more information visit our controlled shot peening page or alternatively contact us to discuss your requirements.