JPH0881723A - Chromium copper and contact chip and cap chip for welding machine - Google Patents

Abstract

PURPOSE: To produce the chromium copper capable of reducing cutting resistance without impairing its characteristics of high hardness and high electric conductivity and produce a contact chip and a cap chip for a welding machine using the same. CONSTITUTION: This chromium copper is constituted of solid solution essentially consisting of copper and contg., by weight, 0.5 to 2.0% chromium and 0.01 to 1.0% tellurium. On the other hand, the contact chip and cap chip can be obted. by subjecting a block 7 using the same chromium copper as a stock to cutting into a shell shape. A through hole 10 provided on the center shaft part of the contact chip is the one for putting through a welding wire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact tip for a welding machine, a chrome copper having a high conductivity and a hardness suitable for a material of an electric contact such as a cap tip, and a contact tip cap for a welding machine using the same. It's about chips.

[0002]

2. Description of the Related Art Chromium copper obtained by adding a small amount of chromium to copper to form a solid solution exhibits high hardness and high electrical conductivity. Therefore, it is used as a material for electric contacts such as contact tips for welding machines and cap tips.

There are various types of contact tips and cap tips for welding machines. The shell-shaped contact tip 1 used in the arc welder (MIG or carbon dioxide gas welder, etc.) shown in FIG. 2 has a through hole 2 in its central axis portion, and a welding wire fed out through the through hole 2 3 is a consumable electrode. In this case, the base material 6 is welded in an atmosphere in which the inert gas 5 such as carbon dioxide gas, Ar or He sent through the space between the contact tip 1 and the cylindrical body 4 surrounding the contact tip 1 is used as the shield gas.

As an example, the contact chip 1 has an axial length of about 45 mm and the through hole 2 has a diameter of 1.0 mm.
The welding wire 3 is made of a steel wire having a wire diameter of about 0.9 mm, and this steel wire has a copper plating layer or a rust preventive oil on its surface. There is also a steel wire in which the central shaft portion is filled with flux. Chromium copper is mainly used as the material of the contact chip 1, but Zr copper and chromium Zr are also used.
There are those using copper, Be copper, electrolytic copper, or alumina-dispersed copper.

[0005]

By the way, about 960 ° C.
Since the cutting resistance of chrome copper, which has been increased in hardness by solutionizing in, is large, it is necessary to perform work on a bullet-shaped block or to drill a through hole with a diameter of about 1.0 mm or less in its central shaft part. Cutting work such as drilling is not easy. In particular, in drilling, a through hole of a predetermined length cannot be obtained unless drilling work is repeated by moving back and forth many times. In addition, the through hole is often bent or the drill is often broken, resulting in an extremely low manufacturing yield.

Accordingly, an object of the present invention is to provide a chromium copper and a contact tip / cap tip for a welding machine using the chromium copper which can reduce the cutting resistance without deteriorating the characteristics of high hardness and high conductivity. is there.

[0007]

According to the present invention, in order to achieve the above-mentioned object, copper as a main component and chromium.
Provided is a chromium copper comprising a solid solution containing 5 to 2.0% by weight and tellurium 0.01 to 1.0% by weight.

Further, there is provided a contact tip for a welding machine, characterized in that the above-mentioned chrome copper is used as a material and is machined into a shell shape, and has a through hole for inserting a welding wire in a central shaft portion. To be done.

Further, there is provided a cap tip for a welding machine, which is made of the above-mentioned chrome copper and is made of a block machined into a bullet shape.

[0010]

Since the chromium copper according to the present invention comprises a solid solution containing 0.01 to 1.0% by weight of tellurium (Te),
Cutting resistance can be reduced without impairing the characteristics of high hardness and high conductivity. In other words, it is possible to obtain free-cutting properties that can perform machining such as machining and drilling with high accuracy and smoothly and in a short time. Therefore, especially when used as a contact tip or a cap tip for a welding machine, both the quality and the productivity can be improved.

When the content of Te exceeds 1.0% by weight, the Hv hardness (Vickers hardness) is lowered although the conductivity is not lowered, so that wear due to contact with a welding wire or the like becomes severe. Further, the content of Te is 0.01
If it is less than wt%, the effect of reducing cutting resistance cannot be satisfactorily obtained. On the other hand, if the Cr content is less than 0.5% by weight, high hardness cannot be obtained, and conversely, if it exceeds 2.0% by weight, the hardness is saturated and the conductivity is lowered.

[0012]

EXAMPLES In view of the fact that the conventional chromium-copper for contact chips generally contains 0.84% by weight of chromium, the present invention including those having this composition is shown in Table 1.
Test pieces of different composition were made. First, 6 types of billets for test pieces were cast and hot extruded into bar materials having a diameter of 32 mm. Next, this bar material was solution-treated at a temperature of about 960 ° C. for about 1 hour, and then drawn into a bar material having a diameter of 25 mm and a length of 50 mm. Then, this was aged at a temperature of about 455 ° C. for about 3 hours to obtain a test piece. As can be seen from Table 1, the Hv hardness and the electrical conductivity of the six test pieces after the aging treatment were such that the addition amount of Te was 0.01 to 0.1.
If it is in the range of weight%, the conductivity will be slightly lowered,
The Hv hardness shows a high value.

[0013]

[Table 1]

Table 2 shows the cutting resistance test results of the above-mentioned six kinds of test pieces. This test uses a high speed steel drill with a diameter of 3 mm and measures the drilling resistance in the torque and thrust directions. The rotation speed of the drill was 2360 rpm, cutting oil was used, and the feed rate of the drill was set to three types of 0.05 mm / revolution, 0.08 mm / revolution and 0.13 mm / revolution. As can be seen from Table 2, the torque and the thrust both show low values when the amount of Te added is in the range of 0.01 to 0.1% by weight.

[0015]

[Table 2]

Next, six kinds of contact chips were manufactured by using the above-mentioned six kinds of test pieces as raw materials. First, FIG.
The columnar block 7 shown in (a) was cut out with a metal saw. The block 7 has a diameter of 9 mm and an axial length of 45 mm. Next, as shown in FIG. 1B, a conical portion 8 and a screw portion 9 are formed by reaming on the base end side of the block 7, and then the center of the block 7 is formed as shown in FIG. 1C. A through hole 10 having a diameter of 1.0 mm was drilled in the shaft portion. Since the drilling was performed from the tip end side of the block 7 toward the base end side, the drilled through hole 1
A bend of 0 (center shift) can be seen at a glance when viewed from the side of the conical portion 8. Then, in the step shown in FIG. 1D, the tip end side was cut to form the tapered portion 11, and the shell-shaped contact tip was completed.

Next, the center deviation of the through hole 10 was measured. In this measurement, 0.05 mm on the conical part 8 side
Those having the above center deviation were judged to be curved.

There are 81 test pieces, and the results of the judgment are shown in Table 3. That is, in the case of not containing Te at all, it frequently occurred as 21%, but Te0.071
The content of 5% by weight is 5%, and the content of Te 0.108% by weight or more is none.

[0019]

[Table 3]

The bending of the through hole is more likely to occur as the rotation speed (processing speed) of the drill is higher. According to the experimental results shown in Table 4, the bending that occurs when drilling the chrome copper containing no Te occurs at a rate of 21% when the advance distance per revolution of the drill is 0.4 mm. On the other hand, when the forward distance was set to 0.6 mm, the bending occurrence rate increased to 33%. However,
With chrome copper containing 0.108% by weight of Te, no bending occurs even when the advance distance is set to 0.4 mm to 0.6 mm, and even when the advance distance is set to 1.0 mm. The bending rate is only 5%.
This means that the drilling efficiency can be doubled as compared with the conventional one.

[0021]

[Table 4]

The contact tip has a through hole for inserting a welding wire in its central shaft portion, but in a welding machine such as a resistance welding type which does not use the welding wire, a shell-shaped cap tip having no through hole. Are used as welding electrodes. In this case as well, cutting out from the base material and machining of the tapered portion or the like are required. Therefore, when the chromium copper according to the present invention is used, cap chips can be manufactured with high accuracy and high yield.

[0023]

As described above, according to the present invention, it is possible to obtain chromium copper which is a solid solution having a high hardness and a high electric conductivity and also having a free-cutting property, and welding using the chromium copper as a raw material. Machine contact tips and cap tips can be manufactured with high accuracy and high yield, and since they have particularly high hardness, excellent wear resistance can be obtained even when they come into contact with welding wires and the like.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a manufacturing process of a contact chip according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a main part of an arc welding machine using a contact tip.

[Explanation of symbols]

 7 blocks 10 through holes

Claims (3)

[Claims] 1. A main component of copper and chromium of 0.5 to 2.0.
A chromium copper comprising a solid solution containing 1% by weight and 0.01 to 1.0% by weight tellurium. 2. A contact for a welding machine, characterized by being machined into a shell shape using the chrome copper according to claim 1 and having a through hole for inserting a welding wire in a central shaft portion. Chips. 3. A cap tip for a welder, comprising a block machined from the chrome copper according to claim 1 and shaped like a shell.