Repair of Erosion Defects in Gun Barrels by Direct Laser Deposition

In recent years the development of functional carbide coatings follows the trend to use composite powders with fine grained hard particles. In addition to thermal spraying, laser cladding is a suitable surface technology in particular for dynamically loaded components, and it is widely used for the manufacturing of coatings as well as complex 3D structures. The paper presents an application addressing the repair of erosion defects in large gun barrels using a novel internal diameter laser cladding head. The most promising material systems are TiC- and VC-based metal-matrix composites. Samples were evaluated in a special erosion test that emulates realistic load conditions. In this test, the materials are exposed to extreme stresses by temperature and pressure shocks, a very reactive atmosphere and erosive particles. As result, TiC-based coatings showed the best performance, and they are applicable for both repair and surface protection of inner surfaces of components and tools.