Hard protective layers on forging dies—development and applications

Abstract

The article presents a summary of many years of activities in the area of increasing the durability of forging dies. The results of comprehensive research work on the analysis of the destructive mechanisms of forging dies and the possibility of increasing their durability with the use of modern surface engineering methods are presented. Great possibilities in terms of shaping operational properties of forging dies by producing hybrid layers of the “Nitrided Layer + PVD Coating” (NL + PVD coating) type were confirmed. An analysis of changes in forging dies durability under various operating conditions was performed, i.e., forging—die—forging press—pressures. It has been shown that the variety of parameters of the forging process, including forgings’ geometry and weight, materials, precision, pressures applied, and, what is very important, quality of machines, makes it very difficult to compare the effectiveness of various PVD coating solutions in the process of increasing the durability of forging dies. Hybrid layers of the “NL + PVD coating” type create great possibilities in shaping the operational properties of tools and machine elements. However, in each application a precise diagnosis of the wear mechanism and the design of an individual PVD coating material solution is required.