Understanding the Peening Time Paradox The Key to Uncoupling Intensity and Coverage

Author:  John Cammett, Consultant, Nadcap Auditor and Lead Instructor
Source:  The Shot Peener magazine, Vol 28, Issue 2, Spring 2014
Doc ID:  2014016
Year of Publication:  2014
Abstract:  
What I refer to as a time paradox is only a seeming paradox. Time is used in the standard protocol for determining peening intensity, yet intensity itself is independent of time during peening provided that machine settings or other key parameters are not altered during the process. This may seem paradoxical though in reality it is not. Coverage certainly is time dependent because an increase in exposure time during peening results in more impact dents on the surface of the part. One of the continuing challenges encountered in my twenty-plus years of teaching shot peening in training and workshop sessions has been to get students to grasp the difference between intensity and coverage concepts and their separate relationship to time.