Development of an in situ Plasma Treatment of X155CrMoV12 for a (Cr,Al)N PVD Tool Coating for Dry Metal Forming in Cold Forging

Cold forging processes are of great importance in production engineering due to the high material utilization and the associated energy and resource efficiency. Liquid and solid lubricants are used in order to perform cold forging processes successfully. These lubricants are often questionable due to ecological, economic, and legislative reasons. For these reasons, dry metal forming exhibits an increased research potential in surface engineering. The absence of lubricants in dry metal forming contributes significantly to the waste reduction in manufacturing processes and to the goal of a lubricant-free factory. Coated metal forming tools may enormously reduce tool and workpiece wear in cold forging or deliver special functions even in the absence of the lubricants. However, the abdication of lubricants goes along with the requirement that the dry tribological system has to withstand the increased tribological loads. In this contribution a (Cr,Al)N PVD tool coating and an in situ plasma etching process are developed to ensure a sufficient adhesion strength on the tool material X155CrMoV12 (DIN 1.2379, AISI D2). Such a plasma treatment of the substrate is necessary for the coating to withstand increased tribological tool loads in dry metal forming