Influence of the application of a PN+CrN hybrid layer on improvement of the lifetime of hot forging tools

This article presents the results of field tests of forging tools in a selected hot forging process of cover plate. The tools with PN+CrN hybrid layer, applied to improve their operating life, were tested in comparison to gas-nitrided tools. The hybrid layer was produced on a plasma-nitrided substrate, onto which a PVD Cr/CrN coating was deposited. All analyzed tools were tested in industrial conditions by manufacturing specific quantities of forgings. Next, the wear of each tool was analyzed by surface scanning and comparison to the CAD model. All tools were checked for changes in the surface layer under a scanning electron microscope. The tests confirmed the effect of improved forging tool lifetime thanks to the application of the PN+Cr/CrN hybrid layer.