Explosive Autofrettage of Cannon Barrels
Final rept. 24 Apr 1969-24 Feb 1971
MARTIN MARIETTA AEROSPACE DENVER CO
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The object of this program was to determine the feasibility of autofrettaging cannon barrels with explosives. The study involved determining the applicability of, the reliability of, and the scaling laws associated with the process. The results of this study provide the basis for the establishment of specifications and procedures for the explosive autofrettage of 152 mm gun barrels. The study consisted of mutually supportive experimental and analytical programs conducted concurrently. An experimental process was undertaken to determine the expansion produced at the bore of a tube, which modelled the breech section of the 152 mm gun tube, due to different amounts of explosive material along the bore of the tube. It was found that the explosive process could be controlled to produce the desired residual bore expansion. Using results of the analysis to make changes in the experimental approach, a method of expanding the tubes explosively was developed which gave acceptable results in both the 20 and 40 models of the breech section and also with a 40 scale model of the entire M81, 152 mm gun tube. The process was scaled up and applied to a breech section of a 105 mm gun tube.
- Fabrication Metallurgy