Composite electrode wire for use in electroerosion machining has coating of gamma-brass with fissures filled by beta-brass under-layer

摘要

The electroerosion electrode wire (1), comprising a copper, copper alloy or brass core (2) and a brass coating, has the coating made from an under-layer (3) of beta-brass and an outer layer of gamma-brass (4) with fissures (5a) that are filled at least partially by beta-brass from the continuous under-layer. The combined thickness of the two brass coating layers is less than 10 per cent of the overall diameter of the electrode wire, and the outer surface can be oxidised, with either a dull or bright finish. An independent claim covers the manufacture of the electrode wire from a zinc-coated core which is drawn and heated to 200 - 400 degrees C to produce the beta- and gamma-brass phases.