Nano-Structured Tungsten Carbide Coating Reduces Wear of Tooling for Extrusion and Abrasive Materials Forming

Abstract

This paper presents the applications of advanced CVD Tungsten Carbide coating to extend the life of tooling used for forming abrasive and corrosive materials.Hardide nanostructured Tungsten Carbide coating combines high hardness (70-77Rc) with excellent toughness. Unlike other hard coatings Hardide can produce a conformal coating layer on complex-shaped tools, including internal surfaces of extrusion die cavities and moulds. In ASTM G65 test the Hardide coating abrasion resistance exceeded WC/Co (9%) cemented carbide by a factor of 4X, and D2 tool steel by 10X. Thus the coating can significantly increase the life of D2 steel tooling used for forming abrasive materials and by maintaining better dimensional tolerances and surface finish of the tool it will manufacture better quality products.The Hardide coating has enhanced resistance to corrosion and aggressive media, including acids; this makes the coating especially suitable for the tooling used in forming uPVC, PTFE and other corrosive materials.The Hardide coating has been tested on extrusion and pelletizing dies processing abrasive and corrosive slurries and typically showed a 3X increase in the life of the tooling. Similar results were achieved by the coating of powder compaction punch/die sets for pharmaceuticals tableting.