Wear of uncoated and PVD coated cemented carbide tools for processing of copper based materials part II: Exploring the sliding contact with pure copper

Abstract

Cemented carbide tools are successfully used to shear Cu alloy wire into zipper elements in the zipper industry. However, wear of the tools is the limiting factor for the production rate and the industry would benefit from more wear resistant tools. Previous investigations have indicated that the wear is tribochemical, and to investigate the role of Zn in commonly used Cu alloy testing is repeated against pure Cu in this work. The tool material used is a cemented carbide, in uncoated, CrC coated and CrN coated versions. The tests are performed in a simplified sliding test rig, combined with intermittent scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis.The tools are gradually worn and Cu is adhered and transferred to all tool surfaces. This process results in a pattern consisting of ridges and valleys on uncoated cemented carbide and CrC. Both are worn significantly faster than CrN, where much of the original surface roughness still remains after the full test. These worn surfaces are similar to the corresponding surfaces worn against the previously tested Cu–Zn alloy. However, the wear rate is dramatically higher in the pure Cu tests.