Processing of Composite Gun Tubes with GLEEM and Hammer Forging

Abstract

Refractory metal liners have been shown to extend the service life of gun tubes a considerable amount. The major technical hurdle to date has been keeping the liners in place during firing. To address this problem, composite gun tubes made of steel and pure niobium have been fabricated through a combination of the GLEEM (gun liner emplacement with an elastomeric material) and the hammer forging. The three barrels made by this approach were test fired in single-shot and burst-fire mode. One of the barrels whose liner had been cold-sprayed with tungsten carbide particles before the GLEEM process showed no liner movement in any of the tests. The success of this new liner processing technology to prevent liner movement offers the potential for further investigations of refractory metals that are more suitable as liner materials.

Keywords:

• Composite
• Elastomer
• Firing
• Gun
• Hammer-forge
• Liner
• Niobium

ACKNOWLEDGMENTS

The author wishes to acknowledge the assistance of Bob Sewell of FN Manufacturing who was instrumental in providing the hammer forging support. Mike Gallante of the Aberdeen Test Center and Thomas Puckett of the U.S. ARL conducted the rapid and single-shot firing tests, respectively. Thanks go to Micah Gallagher and James Catalano for the preparation of the micrographs of the niobium liners. Finally, Hoang Nguyen is acknowledged for his help in applying the GLEEM process to the niobium liners.