Microcracks repairing technique for gun barrel

摘要

When a gun fires the diffusion of chemical species from the propellant gas, such as CO, CO_2, H_2, H_2 O and N_2, into the hot surface through the microcracks forms reaction products and speeds up the erosion process. Therefore, crack repairing and healing can be a possible measure for protecting against erosion of gun bore. The present study develops a novel nanocomposite with the size of 30 -150 nm to repair and heal the microcracks so that the propellant gas can be prevented from reacting with the steel. Sample of gun steel 40CrNiMoV plate (10 mm x 10 mm x 2 mm) is prepared and a fishtail crack is generated through a repeated plastic deformation process. The crack-repairing results show that the fishtail crack become shorter and narrower. A new phase is formed, which is found to have the elements, such as Ca, La, from the raw materials of nanocomposite by energy spectrum analysis.