Wire electrode for electric discharge cutting processes

Abstract

The invention relates to a wire electrode (1, 1') for electric discharge cutting processes and a method for the production thereof. The wire electrode (1, 1') has a core (2) containing a metal or a metal alloy, and a coating (3, 4; 3, 4, 5) that surrounds the core (2) and includes one or more coating layers (3, 4, 5), at least one (3) of which contains a phase mixture of beta-brass and / or beta'-brass and gamma-brass. In said at least one coating layer (3) containing beta-brass and / or beta'-brass and gamma-brass, the beta-phase and / or beta'-phase and the gamma-phase are arranged next to each other in a fine-grained structure in which the mean size of the beta-brass and / or beta'-brass grains and the gamma-brass grains amounts to a maximum of 5 [mu]m relative to the cross-section extending perpendicular to the longitudinal axis of the wire electrode (1, 1'). In order to produce the wire electrode (1, 1'), a wire is used that has a coating layer predominantly containing gamma-brass, and a homogenizing step is carried out in which the gamma-brass is substantially transformed into a beta-brass having a minimum zinc concentration of 51 percent by weight at temperatures exceeding 600 DEG C, and the wire (1, 1') is finally cooled, a process during which zones of gamma-brass are separated from the supersaturated solid solution of beta-brass.

Description

technical field [0001] The invention relates to an electrode wire used for cutting by electric discharge machining or electric discharge corrosion cutting, and a manufacturing method thereof. The wire electrode has a core comprising a metal or metal alloy, and a sheath or coating surrounding the core and comprising one or more cladding or coatings, wherein at least one cladding or coating comprises Phase mixture of beta and / or beta' brass and gamma brass. Background technique [0002] Electro-discharge machining (EDM), or spark erosion, is used to separate electrically conductive workpieces and is based on the removal of material by an electrical discharge between the workpiece and the tool. For this purpose, a controlled spark discharge is carried out between each workpiece and the tool in a non-conductive liquid, such as deionized water or oil. The tool is placed in close proximity to the workpiece and functions as an electrode by applying voltage pulses. In this way, wo...

AI Technical Summary

Problems solved by technology

However, it was found here that in the case of adding a brittle phase, such as a gamma-phase coating, firstly, the performance does not necessarily increase as the coating thickness increases (see EP1295664), and secondly, the formability of thicker coatings may or may not be improved. Processability is limited, which is not conducive to economical production (see US5945010)

In addition, the wear rate of gamma brass coatings is higher than that of beta brass coatings, and in practice, the former often reduces cutting performance

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