Why Cheaper Tools Wear Out Faster When Cutting Brass
A new study reveals why zinc content in brass dramatically affects tool lifespan during manufacturing—a finding that could reshape purchasing decisions for zipper makers and other metal-cutting industries. Researchers discovered that zinc acts as a chemical shield against oxidative wear, meaning cost-cutting material substitutions can multiply tooling costs.
Originaltitel: Exploring the tribochemical wear and material transfer caused by Cu15Zn alloys on shearing tools
<p>Cemented carbide tools are extensively used in the zipper industry, including shearing of a pre-formed Cu15Zn wire into individual zipper elements. Although the work material is significantly softer than the tool, wear is the life limiting factor for the tools and is considered to be of tribochemical nature. So far it has not been explained, however, it is known that the wear rate of uncoated, as well as CrC and CrN coated, cemented carbide increases dramatically when Zn is omitted from the Cu alloy. In this paper, worn tool surfaces, including any transferred material, were studied to investigate the tribochemical wear mechanism in detail. Material transfer occurred onto all tool surfaces. Cu and Zn were separated on the sub-micron scale, and preferential transfer of one of the constituents was observed. This is reflected in the outermost surface of the sheared element, which shows a homogeneous composition elsewhere. Oxidation was observed of all tool surfaces, which indicates elements of oxidative wear. Further, any Zn transferred to the tool surfaces was oxidized. Thus, it is suggested that the presence of Zn reduces the oxygen available and consequently reduces the oxidation rate of the tool surfaces, leading to the protective effect previously observed.</p>