Abstract: Tungsten metal powder of controlled particle sizes is obtained in a fluid bed process by reducing particles of tungsten oxide having the formula WO.sub.X where x is from 2.5 to 3.0. The WO.sub.X powder particles are heated to and then maintained at a temperature between 650.degree. and 1000.degree. C. in a reducing atmosphere, which is maintained by passing a mixture of hydrogen gas, water and optionally nitrogen gas through a fluid bed of the tungsten oxide particles until substantially all of the powder solid is tungsten dioxide, WO.sub.2. The ratio of water partial pressure to hydrogen partial pressure in the feed gas is equal to or slightly higher than the equilibrium partial pressure ratio. The flow of water vapor is then discontinued, either gradually or instantaneously, while maintianing the flow of hydrogen gas to reduce the WO.sub.2 to tungsten metal. By maintaining the ratio of water partial pressure to hydrogen partial pressure above the equilibrium value until the original WO.sub.

Abstract: A wire electrode for a traveling wire EDM apparatus that comprises a copper clad steel core that is clad with a homogenous, outer brass layer using a classical bonding process. The copper clad steel core has a conductivity in the range of 50%-70% IACS (International Annealed Copper Standard) and the brass layer comprises 35%-50% by volume of the electrode. The brass layer comprises 65% copper and 35% zinc in an optimum construction. For a wire electrode having an overall diameter of 0.010 inches, the outer homogenous, brass layer is substantially 25 microns thick when the brass comprises 35% by volume of the wire and the copper clad steel core has a conductivity of 60% IACS and is contructed from AISI 10006 steel wire.

Abstract: An improved electrical discharge machining electrode permitting improved cutting action to be achieved at the same level of electrical power being applied to the wire electrode. Such improvement is attributable to a particular configuration and the material being employed in the wire electrode which has an iron alloy core coated with an intermediate layer including a copper and zinc heat reaction product on which is deposited an adherent carbon surface coating. The improved method and apparatus for employment of this electrode is also described along with one method to form the multilayer coating on the electrode wire core.