Army howitzer gun tubes made from high strength gun steel, which is affordable and strong but susceptible to corrosion. They are also susceptible to stress corrosion cracking because they are autofrettaged. Field usage causes pitting and cracking in bore evacuator holes. The Army needs an affordable method of detecting, typing (Pit Crack Cracked pit) and sizing corrosion damage in bore evacuator holes at field maintenance levels. Presence of any pitting in the bore evacuator holes is cause for condemnation because it is currently not possible to detect cracks at the bottom of the pits. A portable inspection device is needed to determine if cracks are present so that condemnation criteria can be relaxed and crack size substituted as reduced EFC criteria. Formal investment in portable inspection equipment for crack detection is important as it will likely be useful throughout the Army. TRI/Austin proposes to develop a multimodal NDT device, using two complementary modalities, to examine flaws in internal surfaces of holes in steel structures. TRI/Austins NDT Toolbox software for analyzing, manipulating, and fusing NDT data will be used to decrease false positives while maintaining detection reliability. NDT Toolbox can also assist in creating probability-of-detection curves.
