Increasing the durability of large-calibre cannon barrels through strengthening them by surface plastic deformation

Abstract

The paper presents a technology for strengthening the internal surface of the bore of cannon and tank barrels through surface plastic deformation. It is recommended to carry out the strengthening treatment in two stages: firstly, ball peening of the inner working surface of the barrel with hardened steel balls; secondly, application of a heat-resistant hard alloy coating using deforming bodies made of the VK6 alloy. It was established that as a result of this strengthening treatment, residual compressive stresses are formed in the near-surface layer of the bore material, its surface microhardness increases, and the resistance of the metal in the working surface of the barrel against burnout and cracking improves. Overall, the resistance of the barrel material to wear during cannon shots increases. A design of the strengthening device for this treatment has been developed. It consists of a cylindrical hardener with deforming bodies, an electric drive motor and a torque transmission mechanism from the motor shaft to the hardener. During the strengthening treatment, the device is moved along the channel of the cannon barrel, allowing the hardener to roll over the processed inner surface of the barrel and peen its material. The provided strengthening thickness is 0.15–0.20 mm, while the thickness of the applied hard alloy coating is up to a 100 μm.