Theoretical Principles of Shot Peening Coverage

Author:  Dr. David Kirk, Coventry University, U.K.
Source:  The Shot Peener magazine, Vol 19 / Issue 2, Spring 2005
Doc ID:  2005145
Year of Publication:  2005
Abstract:  
INTRODUCTION Coverage is arguably the most important variable in shot peening. It is defined as the percentage area of a surface that has been impacted. This paper examines the major factors that influence the increase in coverage that occurs as peening progresses. A secondary objective is to stimulate debate on the vexed question of "What is 100% coverage?" In the 19th century investigators recognized the need to reduce information to numerical values in order to avoid the ambiguity of verbal description. Even with numerical description there is room for ambiguity. Lewis Carroll's Governor was on firm ground when he said, "Surely Her Radiancy would admit that ten is nearer to ten than nine is - also nearer than eleven is." Less firm would be a shot peener's assertion that "100% coverage is nearer to 100% coverage than is 300% coverage."