Gun barrels are subjected to wear and erosion from the hot propellant gases and high loads from the passage of projectiles.Sustained fire duration and rate of fire are largely limited by barrel thermal considerations, since the heat buildup in the barrel can cause rounds to fire prematurely (cook-off) or weaken the barrel and cause catastrophic failure. A cost effective solution of using a wear resistant liner with an inexpensive outer jacket has long been sought. Tantalum liners are proving effective for larger calibers but the methods for liner application are not suitable for small calibers. This proposal is for a new method to form and bond liners in place in 5.56 and 7.62 mm caliber barrels. The method plastically forms the liners in place and then metallurgically bonds them to the barrels through a thermal process. The process has been demonstrated on small bore tubes of titanium and steel outer jackets, with Stellite and refractory metal liners.The goal of this project is to demonstrate a manufacturing method to produce bimetallic gun barrels with 2-3 times the wear resistance, better thermal performance and cost less than existing gun barrels.
