Draw die for metal wire - has hardened body with vapourized diamond deposited on hole surfaces

摘要

A die for drawing thin metal wires is made from hardened steel or sintered carbide (1). Since the die hole is subjected to extreme frictional wear, the harder the surfaces (2, 3, 4) of the die hole, the longer is its useful life. This is achieved by placing the die with the preformed hole in a vacuum chamber so that vapourized diamond can be deposited on the hole surfaces by means of a cathodic gas discharge. A layer of 0.5 to 5 mu m is formed in this way. The hole in the metal body is so dimensioned that no further treatment is required after the formation of the diamond layer.