JPH06240426A - Production of high strength copper alloy trolley wire - Google Patents

Abstract

PURPOSE:To produce a high strength copper alloy trolley wire by specifying hot rolling and wire drawing conditions for a copper alloy containing specific amounts of tin. CONSTITUTION:A cast stock of a cooper alloy having a composition consisting of 0.4-0.7wt.% tin and the balance copper with inevitable impurities is hot-rolled at >=700 deg.C, and the resulting rolled stock is rolled at <=500 deg.C into a rough-drawn wire of >=30kg/mm<2> tensile strength and this rough-drawn wire is wiredrawn into prescribed shape, that is, tin content is increased and hot rolling, finish rolling, and further wiredrawing are performed by which the trolley wire having superior electric conductivity and high strength can be produced. Moreover, because a copper alloy as simple substance is used in this method, the effect of the ease of recycling is also obtained, as compared with the conventional copper coated steel wire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high-strength copper alloy trolley wire, which is suitable as a trolley wire for a train having high strength and high operating speed.

[0002]

2. Description of the Related Art Conventionally, copper or a copper alloy has been used as a material for a trolley wire because of its excellent conductivity. As a copper alloy for the trolley wire, for example, tin (S
There is a copper alloy containing n) in an amount of 0.25 to 0.35% by weight and the balance copper and inevitable impurities (Japanese Patent Publication No. 59-43332).
issue). The trolley wire made of this copper alloy has an advantage that the conductivity is as good as about 75% of that of pure copper and the wear resistance is also excellent.

A copper or copper alloy trolley wire is usually manufactured by producing a copper or copper alloy rough drawn wire by a continuous casting and rolling method.
It is manufactured by cold drawing this rough wire and forming it into a predetermined shape.

By the way, in recent years, as represented by the Shinkansen, there is a demand for improvement in the operating speed of electric trains. In order to increase train operation speed, it is important that stable current collection is possible between the pantograph and trolley line. For this purpose, it is necessary to increase the overhead wire tension of the trolley wire and increase the wave propagation velocity of the trolley wire. The wave propagation velocity is proportional to (T) ^1/2 where T is the overhead wire tension.

Recently, as a trolley wire having a higher tensile strength than that of a copper or copper alloy trolley wire, a copper-coated steel wire in which a steel wire is used as a core material and copper is coated around the steel wire is used. became. This copper-clad steel wire has the advantage that it has high strength because the steel wire is the core material and that it also has excellent conductivity because it is coated with copper. For example, the strength of copper-clad steel wire is 60 kg
f / mm ² or more, and the conductivity is about 60% of pure copper.

Such a copper-clad steel wire is manufactured, for example, by immersing the steel wire in molten copper and adhering and solidifying the copper on its peripheral surface (Japanese Patent Publication No. 2-11460).

[0007]

However, the above-mentioned conventional trolley wire has the following problems. That is, the trolley wire made of copper or copper alloy has insufficient strength and cannot be applied to a train having a high operating speed.
It is possible to further increase the strength of the copper alloy by increasing the Sn content as compared with the copper alloy disclosed in JP-B-59-43332, but if this is done, the electrical conductivity will decrease significantly. On the other hand, the copper-clad steel trolley wire has a drawback that the manufacturing method becomes complicated because it is necessary to manufacture a steel wire and coat the circumference of the steel wire with copper. Further, the copper-clad steel wire has a drawback that it is necessary to separate copper and steel when recycling, and the treatment is extremely complicated.

The present invention has been made in view of the above problems, and produces a trolley wire which is made of only a copper alloy, is easy to recycle, has high strength, and can be applied to a train having a high operating speed. An object of the present invention is to provide a method for producing a high-strength copper alloy trolley wire that can be used.

[0009]

The method for producing a high-strength copper alloy trolley wire according to the present invention comprises a copper alloy containing 0.4 to 0.7% by weight of tin, the balance being copper and inevitable impurities. A step of hot rolling a cast material at a temperature of 700 ° C or higher to obtain a rolled material, and a step of rolling this rolled material at a temperature of 500 ° C or lower to obtain a rough drawn wire having a tensile strength of 30 kg / mm ² or more. And a step of drawing the rough wire into a predetermined shape.

[0010]

In the method of the present invention, a cast material of a copper alloy containing 0.4 to 0.7% by weight of tin (Sn) and the balance of copper and unavoidable impurities is hot-rolled at a temperature of 700 ° C. or higher. Then, for example, this rolled material is water-cooled and further rolled at a temperature of 500 ° C. or lower to obtain a tensile strength of 30 kgf / mm ²
Get the above rough line. In this way, after hot rolling, by performing finish rolling at a relatively low temperature, it is possible to improve the conductivity even if the tin content is the same, as compared with the case of finish rolling at a high temperature. Obtainable.
In other words, even if the tin content is increased to increase the strength, if hot rolling and finish rolling are performed as described above,
The decrease in conductivity is suppressed, and as a result, it is possible to obtain a rough wire having high strength and good conductivity. When the wire is drawn, the strength is further improved. That is, in the present invention, since the strength of the trolley wire is improved in this way, good conductivity can be obtained even if the Sn content is relatively large.

The Sn content of the copper alloy used as the material is 0.4
It is necessary to be 0.7 to 0.7% by weight. Sn has the effect of improving the strength of the copper alloy. However, if the Sn content is less than 0.4% by weight, sufficient strength cannot be obtained. Further, when the Sn content exceeds 0.7% by weight,
The conductivity is significantly reduced. Therefore, the Sn content is 0.
It is necessary to be 4 to 0.7% by weight.

If the temperature during hot rolling is less than 700 ° C., it becomes insufficient to destroy the directional cast structure to form a uniform recrystallized structure. Therefore, the temperature during hot rolling needs to be 700 ° C. or higher. The temperature at the time of further rolling (finish rolling) after hot rolling is 500
It must be below ℃. If the temperature during rolling exceeds 500 ° C., recrystallization occurs and sufficient strength cannot be obtained. Therefore, it is necessary that the temperature at the time of further rolling after the hot rolling is 500 ° C. or lower.

[0013]

EXAMPLE Next, the results of actually manufacturing a trolley wire by the method of an example according to the present invention and examining its performance are as follows.
Description will be made in comparison with a comparative example outside the scope of the claims.

First, using a continuous casting and rolling apparatus in which a mold is composed of a wheel and a belt, a casting bar of a copper alloy containing Sn in a content shown in Table 1 below, with the balance being copper and inevitable impurities. Was manufactured. The cross sectional shape of this casting bar is a rectangle having a width of 110 mm and a height of 50 mm. The conventional copper alloy is the alloy disclosed in Japanese Patent Publication No. 59-43332.

Next, these casting bars were hot-rolled at a temperature of 750 ° C. to obtain wire rods having a diameter of about 30 mm, and then water cooling was carried out for Examples 1 to 3 and Comparative Examples 3 and 4 to obtain wire rod temperatures. Was cooled to the rolling temperature shown in Table 1 and then further rolled to obtain a rough drawn wire having a diameter of 19 mm. Also,
In Comparative Examples 1 and 2 and the conventional example, finish rolling was performed at a temperature of 750 ° C. to obtain a rough drawn wire having a diameter of 19 mm. In addition, normally, the operations from casting to rolling are continuously performed. However, these operations are not necessarily continuous and may be finished by once cooling to room temperature and then heating to the finish rolling temperature.

Next, these rough drawn wires were subjected to wire drawing to manufacture grooved trolley wires having a height of about 12.3 mm. The cross-sectional area of each of these trolley wires is 110m.
m ² . Then, the tensile strength and conductivity of these trolley wires were measured. The results are also shown in Table 1 below.

[0017]

[Table 1]

As is clear from Table 1, the conductivity of each of Examples 1 to 3 is 61% IACS or more, which is about the same as or higher than that of the copper-clad steel wire.
Further, in these Examples 1 to 3, the tensile strength of the rough wire is 30 kgf / mm ² or more, and the tensile strength after wire drawing is 50 kgf / mm ² or more, which is significantly higher than that of the conventional example. Has improved. On the other hand, the finish rolling temperature is 750 ° C.
In Comparative Examples 1 and 2, which were high, the tensile strength of the trolley wire was 46 kgf / mm ² or less, which was not sufficient. In addition, Comparative Example 3 having a low tin content was also unsatisfactory in the tensile strength of the trolley wire. Furthermore, the electrical conductivity of Comparative Example 4 having a high tin content was not satisfactory.

[0019]

As described above, according to the present invention, a cast material of a copper alloy containing a predetermined amount of tin and the balance of copper and unavoidable impurities is hot-rolled at a temperature of 700 ° C. or higher. Since the rough drawn wire obtained by rolling at a temperature of 500 ° C. or less is drawn into a predetermined shape, a trolley wire having high conductivity and high strength can be manufactured. Further, since the trolley wire manufactured by the present invention is made of a copper alloy simple substance, it has an effect that it is easier to recycle than the conventional copper-clad steel trolley wire.

Claims (1)

[Claims] 1. A copper alloy casting material containing 0.4 to 0.7% by weight of tin, the balance being copper and inevitable impurities.
Hot rolling at a temperature of 00 ° C. or higher to obtain a rolled material,
This rolling material is rolled at a temperature of 500 ° C. or lower to obtain a wire drawing wire having a tensile strength of 30 kg / mm ² or more, and a step of drawing the wire drawing wire into a predetermined shape. High strength copper alloy trolley wire manufacturing method.