Dual Peening

Author:  Dave Breuer, Metal Improvement Company
Source:  The Shot Peener magazine, Vol 27, Issue 3, Summer 2013
Doc ID:  2013029
Year of Publication:  2013
Abstract:  
Dual peening is used to further enhance the performance of traditional shot peening. Whereas traditional shot peening uses one shot media at a specified intensity range, dual peening adds a secondary shot peening operation. The second peening operation usually uses a smaller diameter media that is peened at a lower intensity than the first peening operation. When the secondary peening is performed, the smaller media is able to pound the high points from the first shot peen into the surface. This has the effect of driving additional residual compressive stress at the outer surface.