Home Forums General Discussion Shot Peening Process, Intensity, Coverage surface compression ?

Hi to all, I have recently discovered that using glass bead (H) at 100 psi suction fead with a 3/8" nozzle has been distorting a bearing.The bearing is blasted proir to lead plating,it is 12" dia. with a wall thickness of .115 and a bronze alloy about 88% copper.Once the plastic deformation has occured from the surface compression can it be reversed? Thanks in advance for any imput

Distortion is caused by non-uniform plastic deformation and is accompanied by a corresponding non-uniform residual stress system. Minor distortion is normally corrected by finish machining. This corrects shape but still leaves a non-uniform residual stress pattern - holding the component, precariously, in its required precise shape. Subsequent shot peening imposes a uniform surface residual stress pattern. This then causes distortion of a component.
Best practice dictates that a component should be stress-relieved before final shot peening. If distortion does then occur it can only be due to non-uniform shot peening.