Exfoliation Corrosion Located by Search Peening

Search peening can be defined as the use of controlled shot peening as a tool to expose subsurface corrosion. The stretching of the surface coupled with the compressive stress induced by the multiple impacts of the shot help to delaminate hidden layers, as is found in exfoliation corrosion.

Recently, Boeing Airplane Company's Defense and Space Group, in association with the United States Air Force, funded a study to determine the application of using shot peening to identify exfoliation corrosion. Metal Improvement Company and British Airways have also developed a method to determine the extent of corrosion so that the removal of damage can be accomplished with a high degree of accuracy. This certifiable controlled process, “search peening,” allows a minimal amount of metal removal, so that engineers have the maximum acceptable material to work with, enabling them to keep tolerances within safe limits.