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An Investigation of Autofrettaging Loose Liners into Thick Shells - Theory and Experiment
Final rept. Dec 1972-Oct 1974
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
Pagination or Media Count:
Local cratering of the expensive, high-strength launch tubes of the AEDC 1,000-ft Hyperballistic Range G has occurred when sabots failed in the launch tube and allowed the model to impact the surface of the bore. The expense and long lead time required to replace such launch tubes necessitated the development of a repair technique to increase the life of the launch tube. The technique developed consists of honing the launch tube to a size large enough to reline with a low cost, low carbon, steel tube. The liner is autofrettaged into place however, some difficulty has been experienced in predicting the pressure required to firmly seat the liners. The prupose of the study reported herein was to determine a more accurate way to predict adequate autofrettage pressures. In the work reported, a 10-in. -long section of a high-pressure launch tube was used to simulate the actual procedure. COntact pressure between the shell and the liner was monitored by means of strain gages cemented to the clearance, pressure level, pressure-holding time, outside diameter of the outer shell, and pressure cycling were considered. Of these variables only the pressure level and the outside diameter of the outer shell had any marked effect on liner seating. Author
APPROVED FOR PUBLIC RELEASE