JPS5858236A - Electrode for electrical heat treatment - Google Patents

Abstract

PURPOSE:To prevent sparking and to improve quality of W wires by using the fine W wires tightened like sponge for the parts of electrodes for electrical heat treatment which anneal the traveling W wire by conducting electric current thereto contact the W wire. CONSTITUTION:A W (tungsten) wire 1 to be annealed is fed continuously by a coiler and is passed between a pair of electrode 3 and 4 provided in a furnace 2. The electrode 3 is fixed but the electrode 4 is held energized by a spring 5; therefore the electrodes 3, 4 contact the wire 1 satisfactorily. In this case, the parts of the electrodes 3, 4 which sre in contact with the wire 1 are formed of the W wires of <=25mu sizes which are tightened like sponge. If a voltage is applied between the electrodes 3 and 4, the wire 1 evolves heat of itself and is annealed. The parts of the electrodes in contact with the wire 1 do not consume early, and since no sparking is generated, the wire 1 is heat-treated uniformly to high quality.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode for electrical heat treatment in which a running tungsten wire is annealed by passing an electric current through it.

Mercury has traditionally been used in electrodes for this type of current-carrying heat treatment, but as its toxicity has become a problem, tungsten wire, a high melting point metal, has been hardened into a sponge-like material instead. It is used.

However, the existing electrodes for current-carrying treatment, which are made of tungsten wires hardened in the shape of strips or strips, tend to wear out quickly and often cause sparks between them and the tungsten wires to be heat-treated, causing excessive heating of the tungsten wires. There is a problem in that the tungsten wire becomes brittle, causing breakage, and deteriorating the quality of the tungsten wire.

The present invention has been made in view of these problems, and it is an object of the present invention to obtain a tungsten wire of excellent quality by eliminating premature wear, preventing sparks, and uniformly heat-treating the tungsten wire. The present invention provides an electrode for electrical heat treatment that can be used for electrical heat treatment.

Embodiments of the present invention will be described below with reference to the drawings.

In the figure, a tungsten wire 1 to be annealed is continuously fed by a winding device (not shown) and passed between a pair of electrodes 3 and 4 provided in a furnace 2. . Electrode 3 is fixed, but electrode 4 is connected to spring 6.
This allows the tungsten wire 1 to move to make good contact with the electrode 3. The contact parts of the electrodes 3 and 4 with the tungsten wire 1 are as follows:
It is made of tungsten wire hardened into a spongy shape. However, when a voltage is applied between the electrodes 3, 3, the tungsten wire 1 self-heats, thereby annealing the tungsten wire 1.

Good results were obtained when the sponge-like tungsten wires 1 of the electrodes 3 and 4 had a wire diameter of 26 μm or less. That is, this wire diameter is 10, 20, 26
, 29, using a sponge-like tungsten wire changed to 507+m, the degree of wear of this tungsten wire and the spark generation rate were investigated, and the results were as shown in the table below. .

(Margin below) (-X-1)
The degree of wear of the tungsten wire for the IT electrode is expressed as the length at which the tungsten wire for the heat treatment can be heat-treated by the tungsten wire for the electrode. In this case, once the contact part of the electrode tungsten wire with the heat-treated tungsten wire wears out, it can be used further by changing the contact surface. The use on the surface is described.

(Kaoru 2) Length of tungsten wire for heat treatment 1000m
Number of sparks per hit.

From the above, as a sponge-like tungsten wire, 25μ
It is clear that when less than m is used, it is possible to prevent premature wear and to obtain very good results with less spark generation.

In the figure, 6 is a gas pipe for feeding inert gas or reducing gas into the furnace 2, 7 is a lid, and 8 is a hook.

As explained above, the present invention is an electrode for electrical heat treatment in which a running tungsten wire is annealed by passing an electric current through it, and the part in contact with the tungsten wire has a wire diameter of 26 μm.
Since it is made of tungsten wire hardened into a sponge-like shape, it is possible to prevent early wear and tear, prevent the formation of snook, and uniformly heat the tungsten wire. Electrical heat treatment f! can eliminate the brittleness of tungsten wire and produce tungsten wire of excellent quality! This is something that can be provided to the public.

[Brief explanation of the drawing]

The figure is a partially cutaway side view showing a heat treatment apparatus equipped with an electrode for electrical heat treatment according to the present invention. 1... Tungsten wire, 3, 4... Electrode. Name of agent: Patent attorney Toshio Nakao and one other person Procedural amendment April 1988 1. Address of the case to the Commissioner of the Japan Patent Office 1986 Patent Application No. 167089 2. Name of the invention 3. Electrode for energization heat treatment 3. Amendment Relationship with the case involving the person who filed the patent application Address: 1006 Kadoma, Kadoma City, Osaka Name (582) Representative of Matsushita Electric Industrial Co., Ltd.
Toshihiko Yamashita 4th Agent 571 Address 6, Matsushita Electric Industrial Co., Ltd., 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture Amend "However" to "However" in the third line of page 3 of the statement of contents of the amendment. Masu.

Claims (1)

[Claims] An electrode for current-carrying heat treatment for annealing a running tungsten wire by passing an electric current therethrough, characterized in that the part that comes into contact with the tungsten wire is made of a tungsten wire hardened into a sponge-like shape with a wire diameter of 25 μm or less. Electrode for heat treatment.