Reduction of forging die wear with the application of ceramic coatings

The ability of forged components to compete with parts formed by other techniques depends to a large extent on the lifetime of the dies used, as tooling costs account for around 10% of the component manufacturing costs. The main problem is die wear. Ceramic materials can be applied to the dies, either as coatings or solid inlays, to improve their wearing characteristics. Both monolayer and multilayer coatings were tested. These consisted of the following materials CrC, CrN, TiAlN and TiN. Dies prepared by a combination of nitriding and monolayer coating (applied by PVD, CVD and PACVD) perform considerably better than nitrided but uncoated dies made of hot-worked steel. The application of multilayer coatings to cold-forming tools and chip removal tools has already proved successful for reducing wear. Wear decreases as the number of layers is increased.