JPH11197738A - Extrusion molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably manufacture a copper extruded article of stably excellent quality by specifying the ratio of the sectional area orthogonal in the longitudinal direction of a copper stock to be extruded by a conform to the sectional area orthogonal to in the longitudinal direction of the extruded article. SOLUTION: A copper or copper alloy stock 3 in which an oxide film and stains on its surface are completely removed is continuously drawn into an introduction passage 4 formed by a wheel 1 to be driven by the guide of a guide roller 10 and a fixed shoe block 5, changed in direction by an abutment 8, and fed into a die chamber 6. The copper stock 3 is turned into a plastic fluid by the friction heat and the high pressure to be generated between the introduction passage 4 and the shoe block 5, and extruded from a die 7 as a rectangular copper wire 9. In this operation, the A/A0 is set to range from 1.5 to 10 where A0 is the sectional area in the longitudinal direction of the copper stock 3, and A is the sectional area orthogonal to in the longitudinal direction of the extruded article 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously extruding a copper or copper alloy wire material by extrusion using a conform.
The present invention relates to an extrusion molding method suitable for forming a rectangular wire, a segmental conductor strand, a copper-coated composite wire, and the like, and particularly to an extrusion molding method for reducing the inclusion of foreign matter in an extruded product.

[0002]

2. Description of the Related Art Conventionally, copper products such as copper pipes, copper rectangular wires and copper wires for segmental conductors, and copper-coated composite wires such as copper-coated steel wires and copper-coated aluminum wires are formed by extrusion molding called a conform extruder. It is manufactured by extrusion molding using an apparatus.

FIG. 1 is a sectional view showing a conventional extrusion molding apparatus. The wheel 1 of the extrusion molding apparatus has a copper material 3
Is formed along the circumferential direction, and is rotatably driven in a certain direction. A shoe block 5 is provided along a peripheral surface of the wheel 1 from above to a side of the wheel 1. The shoe block 5 is provided with a die chamber 6 at a position in a side area of the center axis of the wheel 1. The die chamber 6 is provided with an extrusion die 7 for defining an extrusion shape of a molded product.
And an abutment 8 inserted in the groove 2 of the wheel 1
And These dice 7 and abutment 8
Are fitted in the die chamber 6, and the abutment 8 is arranged so as to be located in the groove 2. At the entrance of the copper material 3 between the shoe block 5 and the wheel 1, a guide roller 10 and an introduction path 4 are provided.
The copper material 3 is guided by the guide roller 10 and the introduction path 4
The copper material 3 is heated by the frictional heat between the introduction path 4 and the wheel 1 in the introduction path 4 and plasticized and fluidized.

When a copper wire is extruded into a rectangular copper wire using the conventional extrusion molding apparatus having the above-described configuration, first, the copper material 3 to be extruded is made of an oxide film on its surface and an oil or the like. With the dirt completely removed, the guide roller 10
Is continuously drawn into an introduction path 4 formed by a wheel 1 guided and driven by a shoe and a fixed shoe block 5, changed direction by an abutment 8, and then supplied into a chamber of a die chamber 6. At this time, the copper material 3 in the introduction passage 4 and the die chamber 6 becomes a plastic fluid due to frictional heat and high pressure generated between the introduction passage 4 and the shoe block 5. Then, the plastic material copper material 3 is extruded from the die 7 as a copper flat wire 9. As described above, according to the conventional extrusion molding apparatus, the copper material can be continuously extruded.

However, when an extruded product is manufactured using this conventional extruder, the quality of the extruded product may be degraded due to abnormalities such as swelling on the surface of the extruded product. Groove 2
Is exposed to the atmosphere at a high temperature after passing through the abutment 8, copper oxide is generated on the surface. A part of this copper oxide can be recovered as scrap called a flash at the time of extrusion molding, but a part remains on the surface of the groove 2 without being recovered. Residual copper oxide 1
Since the wheel 1 is driven into the introduction path 4 by driving the wheel 1, when the copper material 3 is continuously drawn into the introduction path 4, the copper material 3 adheres to the surface of the copper material 3 and is brought into the die chamber 6. The copper oxide 11 is caught in the inside of the extruded product, and the dirt, foreign matter, gas components, and the like brought into the inside of the extruded product cause irregularities such as swelling on the surface of the extruded product. It is lowering.

[0006] Even if no abnormality occurs immediately after extrusion molding, the extruded product may be subjected to a heat treatment such as annealing or a heating test simulating the environment actually used as a subsequent step. May swell on the surface or a large void may be formed inside.

[0007] Therefore, the introduction path which becomes high temperature during extrusion molding,
A method has been proposed in which a reducing gas is blown onto a die chamber and an abutment to suppress oxidation of a material (G).
BB-2241660). Further, a method has been proposed in which the entire apparatus as described above is surrounded by a hood, and the inside thereof is filled with an inert gas or the like to form a non-oxidizing atmosphere, thereby suppressing oxidation (PCT Publication WO95 / 17270).
issue).

[0008]

However, these conventional methods have the following problems.

In the method disclosed in GB-B-2241660, under conditions where the extrusion rate is high and the formation of the oxide and the entrainment of the oxide are carried out rapidly, the reduction reaction cannot be carried out in time, and the entrainment of the oxide occurs. Is not sufficiently suppressed. There is also a disadvantage that the surfaces of the die chamber and the abutment exposed to the reducing gas deteriorate rapidly, and the life of these extrusion tools is shortened. As a result, the cost of the extruded product increases.

On the other hand, the method disclosed in PCT Publication No. WO 95/17270 has disadvantages in that the entire apparatus is covered with a hood, so that workability is extremely deteriorated and the cost of the apparatus increases.

The present invention has been made in view of the above problems, and provides an extrusion molding method capable of preventing a decrease in quality of an extruded product without increasing the cost of an apparatus and an extruded product. The purpose is to:

[0012]

An extrusion molding method according to the present invention is directed to an extrusion molding method having a step of extruding a copper or copper alloy material by a conform, wherein a cross section orthogonal to a longitudinal direction of the copper or copper alloy material is provided. When the area is A ₀ and the cross-sectional area perpendicular to the longitudinal direction of the extruded product is A ₁ , A ₀ / A ₁ is 1.5 to 10.

Another extrusion molding method according to the present invention is directed to an extrusion molding method comprising a step of extruding and coating a copper or copper alloy material around a core material by a conform, wherein the copper or copper alloy material is coated in a longitudinal direction of the copper or copper alloy material. When the cross-sectional area orthogonal to A ₀ and the cross-sectional area orthogonal to the longitudinal direction of the copper or copper alloy coating material in the extruded product are A ₁ , A ₀ / A ₁ is 1.5 to 10. It is characterized by the following.

In order for the present inventors to solve the above-mentioned problems,
As a result of intensive experimental research, the ratio of the cross-sectional area of copper or copper alloy (hereinafter, copper and copper alloy is collectively referred to as copper) material to the cross-sectional area of copper material in the extruded product is made appropriate. As a result, it has been found that the quality reduction of the extruded product due to the copper oxide can be reliably suppressed at low cost.

That is, in the present invention, extrusion molding is carried out with an appropriate ratio between the cross-sectional area of the copper or copper alloy material and the cross-sectional area of the extruded product or the copper or copper alloy coating material therein. The copper oxide remaining in the grooves of the conform wheel is extruded without depositing or compacting with dead metal in the die chamber. Therefore, it is possible to prevent the quality of the extruded product from being deteriorated due to the copper oxide. In addition, since large-scale equipment is not required, an increase in cost can be suppressed.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the extrusion molding method according to the present invention will be further described. The cross-sectional area perpendicular to the longitudinal direction of the copper material and A _0, the cross-sectional area perpendicular to the longitudinal direction of the copper material in the extrusion A ₁ and then these ratios A ₀ / A ₁ when the
Is set to 1.5 to 10, the copper oxide remaining in the groove of the wheel and adhering to the surface of the continuously supplied copper material and being brought into the die chamber is not deposited by the dead metal in the die chamber. And extruded from the die at high speed. Therefore, even when using a conventional extrusion molding apparatus, in the extruded product, the copper oxide is stretched and dispersed in the extrusion direction without being dense, and the crystal grain boundary in a sound structure is divided. Since such defects are unlikely to occur, abnormal portions such as voids are unlikely to develop.

As a result, the surface does not swell immediately after extrusion. Also, when a heat treatment such as annealing is performed as a post-process of extrusion molding, or when a heating test or the like simulating an actual use environment is performed, swelling occurs on the surface or a large void is formed inside the extruded product. Does not occur. That is, a stable and high-quality copper extruded product can be stably manufactured.

Furthermore, the extrusion tool does not deteriorate as in the conventional method using a reducing gas, and the workability is reduced or the cost of the apparatus is increased as in the conventional method in which the entire apparatus is covered with a hood. Also does not invite.

If the ratio A ₀ / A _{1 of} the cross-sectional area is less than 1.5, the copper oxide adhering to the surface of the copper material and being brought into the die chamber is deposited on the dead metal and becomes dense. Extruded from die. As a result, swelling occurs on the surface immediately after extrusion, or swelling occurs on the surface when heat treatment such as annealing is performed as a post-process of extrusion molding or when a heating test or the like that simulates an environment actually used is performed. Or a large void is formed inside the extruded product. On the other hand, when the cross-sectional area ratio A ₀ / A ₁ exceeds 10, the copper oxide is less likely to be deposited and densely formed on the dead metal, and an extruded product of good quality can be obtained. The resistance is remarkably increased and wear of the extrusion tool is increased, and the amount of copper scrap generated at the time of extrusion molding is increased, so that workability is reduced and equipment or tool costs are increased. Therefore, when the cross-sectional area of the copper material is A ₀ and the cross-sectional area of the copper material in the extruded product is A ₁ , the ratio A ₀ / A ₁ is 1.5 to 10.

The shape of the extruded product by the extruder is not limited to a rectangular wire. By selecting a die, for example, it can be extruded into a pipe and a segmental conductor strand. Further, the present invention can be applied to copper composite materials such as copper-coated aluminum wires and copper-coated steel wires.

[0021]

EXAMPLES Examples of the present invention will be specifically described below in comparison with comparative examples that fall outside the scope of the claims.

First, an oxygen-free copper wire (JIS C 1020) having the shape shown in Table 1 below, which is manufactured by a dip forming method, the surface of which is degreased and washed with a solvent, and whose surface oxide is removed by pickling, is extruded. It was supplied to the apparatus to produce a copper flat wire. At this time, the cross-sectional shape of the copper flat wire of each of the examples and the comparative examples was changed as shown in Table 1 below by replacing the die. In the column of copper rectangular wire size in Table 1, 8 × 12 means that the length of one side in the cross section of the copper rectangular wire is 8 mm, and the length of one side orthogonal to this is 12 mm. Indicates that

[0023]

[Table 1]

Next, with respect to the prepared copper rectangular wires of Examples and Comparative Examples, the internal structure was observed, a heating test, a vibration fatigue test, and an evaluation of wear loss of the extrusion tool were performed.

In the observation of the internal structure, by observing the cross section of the copper rectangular wire, the presence or absence of oxide entanglement and the presence or absence of structural defects such as voids were investigated.

In the heating test, the copper flat wire of each of Examples and Comparative Examples was heated at 180 ° C., 400 ° C. or 600 ° C. in a nitrogen atmosphere.
After holding at each holding temperature for 1 hour, cooling was performed and the appearance was observed. If an oxide or a gas component accompanying the oxide is entrained inside the copper rectangular wire, the copper rectangular wire expands and swells on its surface in this heating test. In the case of a rectangular wire or the like, a wire drawing process and a heat treatment process such as annealing may be performed as a post-process of extrusion molding. It is also conceivable that a heat history may be received in an environment in which the device is actually used. Therefore, in the heating test, the absence of abnormalities such as swelling in appearance is a criterion for determining that the quality is good. Then, as a result of observing the external appearance, the case where no swelling occurred was evaluated as ○, and the case where swelling occurred was evaluated as x.

In the vibration fatigue test, fatigue fracture was caused by using a plane bending fatigue tester, and the starting point of the fatigue fracture was identified by observing the fracture surface with a scanning electron microscope. In a normal copper rectangular wire, fatigue failure occurs from the surface where the most strain occurs. On the other hand, in an abnormal copper rectangular wire, fatigue failure occurs due to a defect such as an entrained oxide or voids.

In the evaluation of the wear loss of the extrusion tool, the degree of wear loss of the extrusion tool used for extrusion molding was evaluated. The results are shown in Table 2 below.

[0029]

[Table 2]

As shown in Table 2 above, in Examples 1 to 9, extrusion molding was performed with an appropriate cross-sectional area ratio A ₀ / A ₁ , so that foreign matter and copper oxide were present inside the rectangular wire. No entrapment was observed. In addition, no swelling occurred in the heating test, and the starting point of the fatigue fracture in the vibration fatigue fracture test was the surface and was normal. That is, it can be said that the internal structure of the extruded product is sound.

On the other hand, Comparative Examples 10, 11, 13, 14, 1
In Nos. 6 and 17, the ratio A ₀ / A ₁ of the cross-sectional area is less than the lower limit of the range of the present invention. Was observed. In addition, swelling was observed in the appearance in the heating test. Furthermore, in the fatigue fracture test, fatigue fracture occurs from the cracks in the voids present inside or the voids in the entangled oxide,
Destruction was achieved with a smaller number of strain repetitions than in Examples 1 to 9.

In Comparative Examples 12, 15, and 18, since the cross-sectional area ratio A ₀ / A ₁ exceeded the upper limit of the range of the present invention, a rectangular wire of good quality could be obtained. Since the extrusion resistance of the copper material increased, the wear loss of the extrusion tool became severe.

[0033]

As described in detail above, according to the present invention,
Extrusion is performed with an appropriate ratio between the cross-sectional area of the copper or copper alloy material and the cross-sectional area of the extruded product or the copper or copper alloy coating material therein, so that the copper remaining in the grooves of the conform wheel The oxide is extruded without depositing or compacting with dead metal in the die chamber. Therefore, it is possible to prevent the quality of the extruded product from being deteriorated due to the copper oxide. In addition, since large-scale equipment is not required, an increase in cost can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an extrusion molding apparatus.

[Explanation of symbols]

 1; wheel 2; groove 3; copper material 4; introduction path 5; shoe block 6; die chamber 7; die 8; abutment 9; copper rectangular wire 10; guide roller 11;

Claims (2)

[Claims] 1. An extrusion method comprising a step of extruding a copper or copper alloy material by a conform, wherein a cross-sectional area orthogonal to a longitudinal direction of the copper or copper alloy material is A ₀ , The cross section perpendicular to the direction is A ₁
Wherein A ₀ / A ₁ is 1.5 to 10. 2. An extrusion molding method comprising a step of extruding and coating a copper or copper alloy material around a core material by a conform, wherein a cross-sectional area orthogonal to a longitudinal direction of the copper or copper alloy material is A ₀ , when copper or cross-sectional area perpendicular to the longitudinal direction of the copper alloy coating material in the extrusion molded article was a _1, an extrusion molding method, characterized in that a ₀ / a ₁ is 1.5 to 10.