Quote Originally Posted by MartinS View Post
Fake news alert!!

Peening is the art of creating a compressive stress in a metal surface. (check out ball peen hammer and its uses)

The roots of gear teeth are control shot peened to increase their bensing strength through inducing a compressive stress in the metal surface. Con-rods are strenghtened by shot peening (this also removes suface imperfections). Peening is also used to bend wing surfaces before fitting.

Bead blast and shot blast are similar processes but with different intended results

.......just to clarify.
This man is totally correct and is one of the few with correct engineering information, quite rare these days. It can also be commonly known as 'surface conditioning', which also includes other processes affecting the surface of a component. Well done MartinS!