JP5401670B2 - Method for producing copper-coated aluminum wire - Google Patents

Description

  The present invention relates to a method for producing a copper-coated aluminum wire in which pure aluminum or an aluminum alloy is used as a main conductor and copper is coated on the outer periphery of the main conductor.

  Conventionally, as a wire material for electronic devices, cable conductors and braided wires, various motor coils, etc., pure aluminum or an aluminum alloy is used as a main conductor, and a copper-coated aluminum wire in which copper is coated on the outer periphery of the main conductor has been used. Yes.

  The copper-coated aluminum wire is usually manufactured by the following two steps. The first step is a step of manufacturing a composite wire of a copper-coated aluminum wire by coating copper on an aluminum wire that is a core material formed of pure aluminum or an aluminum alloy, and the aluminum wire is vertically attached to the copper tape. Then, the copper tape is formed into a tubular shape on an aluminum wire, the butt portion of the copper tape is welded by a TIG (tungsten inert gas) method, and the copper tape formed and welded into a tubular shape is reduced in diameter by a roll, and the core material This is a step of closely contacting the aluminum wire. In this process, before winding the composite wire of the copper-coated aluminum wire, a die is used to evacuate the air between the copper tape and the aluminum wire. It is not a die for drawing. In addition to the pipe forming method as described above, a plating method in which copper plating is applied to an aluminum wire is also employed in the first step.

  The second step is a step in which the composite wire of the copper-coated aluminum wire obtained in the first step is drawn using a wire drawing machine and is thinned to a predetermined diameter (for example, Patent Documents). 1). In this step, a die having a predetermined area reduction rate is used, and the composite wire of the copper-coated aluminum wire is gradually thinned. However, the standard for the split of the die is 20%. It is described in.

JP 2007-152398 A

  However, in the second step, that is, the wire drawing step, disconnection due to copper layer peeling due to poor adhesion of the copper tape to the aluminum wire was a chronic problem. There was a problem that a disconnection of the cup and cone type occurred. Therefore, one of the important required qualities of the copper-coated aluminum wire is the wire drawing workability after pipe forming (form welding) of the copper tape.

  Therefore, an object of the present invention is to reduce cup-and-cone disconnection in a wire drawing process for producing a copper-coated aluminum wire, and to improve wire drawing workability and wire drawing yield.

  The present invention as a means for solving the above-mentioned problems is a plurality of used at the time of wire drawing in the production of a copper-coated aluminum wire in which pure aluminum or an aluminum alloy is used as a main conductor and the outer periphery of the main conductor is coated with copper. Among these dies, the area reduction rate of the first die is 26.9% or more and less than 30%, which is a method for producing a copper-coated aluminum wire.

  2. The method for producing a copper-coated aluminum wire according to claim 1, wherein the area reduction rate of the second die among the plurality of dies used for wire drawing is 26.9% or more and less than 30%. It is a manufacturing method of the copper covering aluminum wire of description.

  According to the present invention as described above, in the wire drawing process for manufacturing a copper-coated aluminum wire, it has become possible to reduce the disconnection of the cup and cone type and improve the wire drawing workability.

  Embodiments of the present invention will be described below. The present invention is a method for producing a copper-coated aluminum wire, using pure aluminum or an aluminum alloy as a core material as a core material, and manufacturing a copper-coated aluminum wire in which copper is coated as a coating material on the outer periphery of the main conductor. After the step of manufacturing the composite wire of the copper-coated aluminum wire, a plurality of dies used in the wire drawing process for drawing the composite wire of the copper-coated aluminum wire using a wire drawing machine and thinning it to a predetermined diameter Among them, the area reduction rate of the first die or the second die is 26.9% or more and less than 30%. In addition, the die for extracting the air between the copper tape and the aluminum wire of the core material before winding is used in the pipe forming process, that is, the process of manufacturing the composite wire of the copper-coated aluminum wire. Not a die. The first die means the first die among a plurality of dies used at the time of wire drawing.

  As the main conductor of the copper-coated aluminum wire, pure aluminum (electrical aluminum) or an aluminum alloy can be used, and the aluminum alloy is not particularly limited, but is a high-tensile type, for example, 5 mass% magnesium, the remaining aluminum. In addition to JIS 5056 aluminum alloy, 2.5 mass% magnesium, and the balance aluminum JIS5052 aluminum alloy, for example, 0.5 mass% magnesium, 0.5 mass% silicon, and the remaining aluminum (i) aluminum alloy can be used.

  Although the copper coating layer of a copper covering aluminum wire is not specifically limited, It is preferable that the copper coating space factor which is an area ratio of the copper in the cross-sectional area of copper and aluminum shall be 1-20%. If it is less than 1%, the copper coating layer is likely to be broken, causing disconnection or connection failure. If it exceeds 20%, the core aluminum wire may be easily disconnected at the time of wire drawing. is there.

  The step of manufacturing a composite wire of a copper-coated aluminum wire is a step of manufacturing a composite wire of a copper-coated aluminum wire by coating copper on an aluminum wire of a core material formed of pure aluminum or an aluminum alloy. A known method can be employed using the apparatus, and as the aluminum wire, a continuous drawn and rolled rough drawn wire or a wire formed by drawing the rough drawn wire can be used. As a specific example of this process, the aluminum wire is fed out from the core material supply device, straightened with a strainer, cleaned with a surface cleaning device, and polished with a brush made of stainless steel or synthetic resin with a polishing device. Further, the copper tape is fed out from the copper tape supply device and polished by the polishing device. As an example of the copper tape, an oxygen-free copper drape having an oxygen amount of 10 ppm and having a thickness of 0.4 mm and a width of 42 mm can be used, but it is not limited thereto.

  Then, using the pipe making method, the polished aluminum wire and copper tape are introduced into the forming device, the aluminum wire is vertically attached to the copper tape by the forming device, and the copper tape is rolled onto the aluminum wire so as to cover the aluminum wire. Formed continuously into a tubular shape by forming, the butt portion of the copper tape is continuously welded by the TIG (tungsten inert gas) method, and the copper tape formed and welded into a tubular shape is reduced in diameter by a roll to form a core material It is closely attached to the aluminum wire and wound on a winder. In addition, the process of manufacturing the composite wire of this copper covering aluminum wire can employ | adopt the plating system etc. which apply copper plating to an aluminum wire, without being limited to the above pipe making systems.

  In the wire drawing step, the composite wire of the copper-coated aluminum wire obtained by the above step, in which the copper tape is in close contact with the aluminum wire of the core material, is drawn using a known wire drawing machine until the predetermined diameter is reached. This is a step of producing a copper-coated aluminum wire by thinning, and gradually thinning using a plurality of dies. Here, the wire diameter of the composite wire of the copper-coated aluminum wire is not particularly limited. In this wire drawing process, the drawing speed for pulling the composite wire of the copper-coated aluminum wire may be within a normal range. For example, the outlet drawing speed is about 100 m to 500 m / min on the upstream side, and 500 m to 2000 m on the downstream side. Per minute.

  In the wire drawing process for thinning the copper-coated aluminum wire, the number of dies to be used is not limited, but among the plurality of dies used for wire drawing, the first die or the individual dies of the first and second dies are used. The area reduction ratio is set to 26.9% or more and less than 30%.

  The cause of cup-and-cone disconnection is the internal void (shrinkage cavity) inherent in the aluminum wire. If the die area reduction is small, the wire drawing of the composite wire of copper-coated aluminum wire Without being able to reduce the internal void (shrinkage cavity) inherent in the aluminum wire generated in the casting and rolling stage of the aluminum wire as the core material, the compression process at the time does not reach the inside of the copper-coated aluminum wire, Cup-and-cone disconnection occurs during wire drawing, but by making the area reduction ratio of the first or first and second dies as described above 26.9% or more and less than 30%, The internal void (shrinkage nest) can be reduced, and the disconnection of the cup and cone type can be prevented.

  Thus, the reason why the area reduction ratio of the first or first and second dies is 26.9% or more and less than 30% is that the upstream side of the wire drawing, that is, the initial die of the wire drawing, Specifically, the effect of preventing cup-and-cone disconnection is enhanced by increasing the area reduction ratio of the first die or the first and second dies within a range where disconnection does not occur. Further, if the area reduction ratio of the first die is less than 26.9%, in the wire drawing process for further thinning, wire breakage occurs frequently, and the amount of drawn wire is reduced, and the effect of the present invention is sufficiently obtained. It is because it cannot be obtained. Moreover, if the area reduction rate of the die is set to 30% or more, the pulling force becomes excessive and the wire breaks.

  When the area reduction rate of the first and second dies is 26.9% or more and less than 30%, the area reduction rate of the second die is preferably equal to or less than the area reduction rate of the first die. .

  In addition, the area reduction rate of the second die when the area reduction rate of the third die and after and the area reduction rate of the first die are 26.9% or more and less than 30% are less than 30% without disconnection. If there is no particular limitation, a conventionally used dicing with a reduction in area of about 10 to less than 20% can be used, but in order to increase the amount of wire drawing and improve the effect of the present invention, It is preferable that the area reduction of individual dies from the third die to the eighth die is 20% or more and less than 25%. Furthermore, the first die is not limited to the eighth die, and the first die is not limited to the first die. It is more preferable that the area reduction rate of each die of the ninth die from the die or the tenth die from the first die is 20% or more and less than 25%. It should be noted that the area reduction rate of the 11th and subsequent dies does not affect the drawn wire production amount as long as it is within the range where no wire breaks.

  When the area reduction rate of the second die is 26.9% or more and less than 30%, the area reduction rate of the third die is preferably equal to or less than the area reduction rate of the second die.

  After forming the composite wire of the copper-coated aluminum wire of the copper-coated aluminum wire as shown in Table 1 below in the process as described above by cold working, The wire-drawing process was performed with the die reduction ratio shown in Table 1 to form a copper-coated aluminum wire with a wire diameter of 2.53 mm, and the wire was further drawn to a wire diameter of 1.6 mm and a wire diameter of 0.9 mm without disconnection. Thereafter, the amount of drawn wire in the process of drawing to a wire diameter of 0.135 mm was determined. The area reduction rate of the 11th and subsequent dies was appropriately less than 10 to 25% in order to make the final wire diameter 0.135 mm. Here, the amount of drawn wire means the weight that could be drawn per disconnection, and a larger value indicates that there is no disconnection and wire drawing workability is better.

  In Examples 1 to 33, the area reduction rate of the first die was set to 26.9% or more and less than 30%. Furthermore, in Examples 6 to 10, 13, 14, 17, 18, 20, 22 to 24, 27 to 29, 32, and 33, the area reduction rate of the second die was also set to 26.9% or more and less than 30%. . As comparative examples, in Comparative Examples 2, 4, 6 and 8, the area reduction rate of the first die was less than 26.9%, specifically 26.0%. In Comparative Examples 1, 3, 5 and 7, The area reduction rate of the first die was set to 30% or more, specifically 30%.

  As can be seen from Table 1, in the example in which the area reduction ratio of the first die or the area reduction of the first and second dies was 26.9% or more and less than 30%, the main conductor of the copper-coated aluminum wire As compared with the comparative example in which the surface area reduction rate of the first die was less than 26.9% for each material, the wire drawing yield was improved. In each of the comparative examples in which the area reduction rate of the first die was 30%, the aluminum wire broke during wire drawing with the first die.

  By the method for producing a copper-coated aluminum wire of the present invention, the production efficiency of the copper-coated aluminum wire can be improved, and the copper-coated aluminum wire produced by the method for producing a copper-coated aluminum wire of the present invention is an electronic device, It can be suitably used as a wire material for cable conductors, braided wires, and various motor coils.

Claims (2)

  In the production of a copper-coated aluminum wire using pure aluminum or an aluminum alloy as a main conductor and copper is coated on the outer periphery of the main conductor, the area reduction ratio of the first die is 26 A method for producing a copper-coated aluminum wire, characterized by being 9% or more and less than 30%.   2. The method for producing a copper-coated aluminum wire according to claim 1, wherein the area reduction rate of the second die out of the plurality of dies used in the wire drawing process is 26.9% or more and less than 30%.