Wear of cemented carbide tools in a copper alloy forging process - Verification of a new lab test

Abstract

Cemented carbide tools are commonly used in both shearing and forging processes associated to zipper production. In the actual production, the tool life is often limited by wear after many millions of repeated contacts with copper alloys. A series of previous investigations has shown that the wear of the tools is tribochemical for both shearing and forging, however with different features. The mechanisms causing this wear are not well understood.To gain deeper insights into the active wear mechanisms during the copper alloy forging process, a new tribotester was proposed and developed. By this tester, a cemented carbide cylinder is repeatedly put in sliding contact with a rotating copper alloy cylinder in a crossed cylinders arrangement. The test was interrupted at selected intervals so that the cemented carbide cylinder could be repeatedly evaluated by SEM and EDS. It was revealed that the characteristic wear of actual tools, tribochemical smooth wear in common, and preferential removal of Co binder and partially Zn rich transfer for the forging tool, can be reproduced by this tribotester.