Preparation of the projectile rotating band and its performance evaluation

Alternative materials are being investigated as substitution of the traditional copper rotating band, in order to solve problems associated with their mechanical and physical properties. Meanwhile, new processes for joining the rotating band on the projectile body have also to be developed because of different material physical properties. In this paper, swaging, welding, and newly developed spraying technologies for fabricating rotating band are analyzed, respectively. Quasi-static and dynamic engraving methods are presented for evaluating the performance of as-prepared rotating band. The former was performed on an 810 Material Testing System and the latter was carried out by using a specially developed gas-gun-based impact test rig. Hoop and axial direction strain gauges were positioned on the exterior of the barrel to monitor the effect of the rotating band on the barrel during engraving process. It is suggested that aluminum bronze coating prepared by the High Velocity Arc Spraying (HVAS) process should be a good candidate for application to a rotating band of medium- and large- caliber projectiles. The measured strains were found to be dependent on a set of variables, such as loading rate, band material and structure, forcing cone and rifling (land and groove) structure, bore condition (oiled or dry), etc. The loading rate has been verified as the most important factor and the essential difference among quasi-static engraving, dynamic engraving, and actual firing.