Superior Coating Technology for Advanced Cold Wire Drawing of Spring Steels

Abstract

The technology of cold wire drawing belongs to an ancient class of technologies, but their use lasts for centuries. Today, special forming machines, advanced tool materials and effective lubricants are used. In this paper, a progressive physical vapour technology (PVD) of coating for inner surfaces is used which resulted in significant prolongation of tool life. The technology of HiPIMS (High-power Impulse Magnetron Sputtering) exhibited excellent performance in protective (Al,Ti)N coating of whole inner surfaces that are in contact with the drawn wire which is impossible to do with other coating techniques. The increase in production of the drawn steel spring wire by the coated die by more than 100% was excellent, and it opens new horizons to some similar technological applications.