Reducing Surface Roughness of Cold-drawn Steel via Die Coating Modification

Recently, breakthrough optimisation has been achieved in cold drawing processing. Research teams have adopted mould coating modification to address the industrial challenge of high surface roughness and surface scratches on cold drawn steel. Intense friction between moulds and steel blanks during cold drawing easily triggers metal adhesion and cavity abrasion, resulting in surface defects and limiting the quality upgrade of high-precision component raw materials.

In this solution, PVD nano composite coatings are applied to modify the cavity surface of cold drawing dies. The compact coating lowers the interfacial friction coefficient, prevents cold welding between steel and moulds and minimises scratch damage during drawing. Mass production tests verify obvious reduction in surface roughness of cold drawn steel alongside fewer surface scratches and pits. Meanwhile, cavity wear is alleviated to extend mould service life.

This technology requires no major reconstruction of existing cold drawing production lines and fits round steel and special-shaped steel. Cold drawn steel with improved surface finish cuts stock removal for subsequent turning and grinding, lowering overall processing costs. It is suitable for raw material manufacturing of construction machinery, hydraulic parts and precision transmission components, enabling manufacturers to supply higher-grade precision steel products.