JP2010046710A - Copper for wire and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide copper for wires in which coarse particles of oxidized copper are few in the vicinity of the surface and the generation of the defects such as omission and cracks on the surface of a copper wire are reduced, and to provide a method of manufacturing the same. <P>SOLUTION: The copper for the wires is manufactured by continuously rolling a copper ingot and, when observing a cross section of optional three places, the particles of the oxidized copper, having the maximum diameter of ≥10 μm, being present in the region of within 100 μm from the surface, are ≤15 pieces on an average. In the method of manufacturing the copper for wires, the copper ingot is continuously rolled and rolling roll stands are arranged in multistage from the upstream side where the copper ingot is supplied and, at at least one stand, rolling is performed after the surface temperature of the roll in the biting part of the rolling roll is lowered to ≤60°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to copper for wire and a method for producing the same. In particular, the present invention relates to copper for wire rods that has few coarse copper oxide particles in the vicinity of the surface and can reduce the occurrence of defects such as missing or cracks on the surface of the copper wire.

  As a winding copper wire used for a motor coil, a magnet coil, or the like, for example, a coated wire such as an enamel-coated copper wire obtained by enamelling a copper wire is used.

  The copper wire used for such a coated wire is generally manufactured by rolling and drawing a tough pitch copper ingot manufactured by continuous casting. Specifically, a copper ingot produced from a continuous casting machine is supplied to a multi-stage rolling mill, and the copper ingot is continuously rolled with a plurality of rolling rolls so as to have a predetermined wire diameter, and copper roughing is performed. Processed into wire (copper for wire). And this copper for wire is wound up with a winder (coiler), finally, this copper for wire is supplied to a wire drawing machine, and it is penetrated to a wire drawing die, and a copper wire is manufactured. Usually, the continuous casting process and the rolling process are performed continuously.

  By the way, if there are defects such as wrinkles or bulges in the sheath of the coated wire, the coating is easily peeled off from this, and when an electric current is passed through the coated wire (copper wire), leakage (short circuit) or short circuit (short) may occur. Highly dangerous and very dangerous.

  One of the factors that cause such a defect in the coating of the coated wire is a defect such as a chip or a crack present on the surface of the copper wire. Since the coating of the coated wire is very thin, if there is a defect such as a chip or a crack on the surface of the copper wire, the coating tends to be defective due to the influence. For example, in the case of enamel-coated copper wire, the enamel resin is applied to the copper wire surface and then baked to coat the enamel. In addition, when the resin is baked, the gas in the gap expands and the coating may swell. Therefore, it is desired to use a copper wire excellent in surface properties with few defects such as missing and cracks in the production of the coated wire.

  One of the factors that cause such defects on the surface of copper wire is copper oxide particles pushed into the inside (near the surface) when copper ingot is continuously rolled in copper for wire before wire drawing. The existence of For example, Patent Document 1 discloses a technique for removing copper oxide particles that have been pushed near the surface when a copper ingot is continuously rolled. In Patent Document 1, before the finish rolling step, performing a rolling polishing step of polishing a rod-shaped material while rolling it with a rolling polishing roll, and further, at least of the rolling rolls disposed before the rolling polishing step On the other hand, it is proposed that the rolling roll surface is cleaned by spraying rolling oil at a high pressure.

JP 2007-50440 A

  However, in the prior art, it is difficult to sufficiently reduce the coarse copper oxide particles present near the surface of the copper for wire. Recently, it has been demanded to further reduce defects such as chipping and cracks on the surface of the copper wire.

  As a result of intensive studies by the present inventors, when a large number of coarse copper oxide particles, specifically, copper oxide particles having a maximum diameter of 10 μm or more exist in the vicinity of the surface of the copper for wire, the copper for wire was drawn. In some cases, the copper oxide particles dropped off together with the surrounding structure to generate copper powder, and it was recognized that defects such as missing and cracks were likely to occur on the surface of the copper wire after wire drawing.

  In Patent Document 1, as one means for removing copper oxide particles, it is proposed to perform a rolling polishing process before the finish rolling process. However, as a result of studies by the present inventors, the following was found.

  When a rod-shaped material is rolled, the oxide film on the surface of the material is broken by rolling to expose the new surface, and the new surface and the rolling roll come into contact with each other, so that copper adheres to the surface of the rolling roll and may be baked. Then, the copper baked on the surface of the rolling roll is oxidized to become copper oxide, and coarse copper oxide particles separated from the surface of the rolling roll during continuous rolling are pushed into the vicinity of the surface of the rod-shaped material. For this reason, the rolling polishing step alone is not sufficient in reducing the coarse copper oxide particles present near the surface of the copper for wire rod. As another means, it has been proposed to spray the rolling oil at a high pressure on at least one of the rolling rolls to clean the surface of the rolling roll. This is intended to prevent the copper oxide from being pushed into the rod-shaped material in the rolling process by removing the oxide film peeled off from the surface of the rod-shaped material and adhered to the surface of the rolling roll. Usually, one nozzle is provided in the circumferential direction of the rolling roll for one rolling roll (see FIG. 1 of Patent Document 1). However, even if the rolling oil is sprayed from one nozzle at a high pressure, it is difficult to completely remove the copper adhering to the entire surface of the rolling roll, and some copper may be baked on the surface of the rolling roll.

  The present invention has been made in view of the above circumstances, and one of its purposes is that there are few coarse copper oxide particles near the surface, and it is possible to reduce the occurrence of defects such as defects and cracks on the copper wire surface. The object is to provide copper for wire. Another object of the present invention is to provide a method for producing copper for wire that can reduce coarse copper oxide particles present in the vicinity of the surface of copper for wire.

  The present inventors observe the rolling roll during continuous rolling and the rolled material rolled by the rolling roll, and conduct a detailed study on the generation mechanism of coarse copper oxide particles existing near the surface of the copper for wire rod. It was. As a result, even if the lubricant is sprayed from the nozzle to the rolling roll at a high pressure, a part of the copper adhering to the surface of the rolling roll may be baked as it is, and the seizure preventing effect on the rolling roll is not sufficient. I found that there was no.

  However, when the inventors controlled the rolling roll to increase the flow rate of the lubricant to lower the surface temperature of the rolling roll, rather than spraying the lubricant at a high pressure on the rolling roll, It turned out that copper becomes difficult to adhere, seizure to the rolling roll can be prevented, and as a result, coarse copper oxide particles existing in the vicinity of the surface of the copper for wire rods can be reduced. In addition, when the inventors observed the surface temperature at the biting portion of the rolling roll, it was about 80 ° C. before increasing the flow rate of the lubricant, whereas it was 45 after increasing the flow rate of the lubricant. It was about ~ 50 ° C.

  The present invention has been made based on the above findings. The present invention will be described in detail below.

  The copper for wire according to the present invention is a copper for wire manufactured by continuously rolling a copper ingot, and when a cross section at any three locations is observed, a maximum diameter of 10 μm or more existing in a region within 100 μm from the surface The number of copper oxide particles is an average of 15 or less.

  According to the copper for wire rod of the present invention, there are few coarse copper oxide particles in the vicinity of the surface, and the generation of copper powder can be suppressed when the copper for wire rod is drawn. It is possible to reduce the occurrence of defects. Here, the average number of copper oxide particles having a maximum diameter of 10 μm or more present in a region within 100 μm from the surface is preferably 10 or less, particularly preferably 5 or less. The maximum diameter of the copper oxide particles referred to in the present invention is the diameter of the smallest circle (minimum inclusion circle) that can include the entire copper oxide particles when the cross section is observed. In the present invention, the cross section is observed over the entire circumference of the copper for wire.

  The copper for wire rod according to the present invention has a maximum of 20 copper oxide particles with a maximum diameter of 10 μm or more at a location where the number of copper oxide particles with a maximum diameter of 10 μm or more existing in a region within 100 μm from the surface is the largest among any three locations. The following is preferable.

  According to this configuration, the maximum number of coarse copper oxide particles is 20 or less, and the occurrence of defects on the surface of the copper wire can be reduced over the entire length of the copper wire.

  Furthermore, it is preferable that the copper for wire rods of the present invention has 15 or less copper oxide particles having a maximum diameter of 10 μm or more at all three arbitrary locations.

  According to this structure, it can reduce more that a defect generate | occur | produces on the copper wire surface over the copper wire full length. Here, the maximum number of copper oxide particles having a maximum diameter of 10 μm or more present in a region within 100 μm from the surface is preferably 10 or less, particularly preferably 5 or less.

  The method for producing copper for wire rod according to the first aspect of the present invention is a method for continuously rolling a copper ingot, and the stands of rolling rolls are arranged in multiple stages from the upstream side to which the copper ingot is supplied. And in at least 1 stand, it rolls by making roll surface temperature in the biting part of a rolling roll 60 degrees C or less.

  According to this manufacturing method, by reducing the surface temperature of the rolling roll, it becomes difficult for copper to adhere to the rolling roll, and seizure to the rolling roll can be prevented. Coarse copper oxide particles can be reduced. Normally, the temperature of the copper ingot produced from the continuous casting machine is about 900 ° C, and the rolling roll of the stand located on the most upstream side is in contact with this copper ingot, so the surface temperature is likely to rise and copper adheres. Easy to do. Therefore, in the first manufacturing method, it is preferable that the surface temperature of the rolling roll is set to 60 ° C. or less in the stand located on the most upstream side. In addition, the biting part of the rolling roll referred to in the present invention is a part facing the upstream side of the rolling roll, and is a place immediately before starting contact with the flowing copper ingot (rolled material). Specifically, in FIG. 2 or FIG. 3, it is a portion indicated by oblique lines from the upper right to the lower left of the rolling roll 2. In the first production method, the roll surface temperature at the biting portion of the rolling roll is preferably 50 ° C. or less.

  In the first manufacturing method, it is preferable to arrange a plurality of nozzles in the circumferential direction of the rolling roll and adjust the roll surface temperature in the rolling roll by spraying a lubricant from the plurality of nozzles onto the rolling roll.

  By disposing the plurality of nozzles in the circumferential direction of the rolling roll and spraying the lubricant from the plurality of nozzles onto the rolling roll, the cooling effect on the rolling roll can be sufficiently ensured.

  Further, it is preferable that at least one of the plurality of nozzles is installed so as to spray the lubricant onto the exit portion of the rolling roll, and the flow rate of the lubricant is preferably over 64 L / min.

  Conventionally, the flow rate of the lubricant sprayed from the nozzle to the rolling roll is about 60 L / min. Therefore, the cooling effect with respect to the rolling roll can be enhanced by increasing the flow rate of the lubricant to more than 64 L / min. Moreover, the exit part of a rolling roll is a location immediately after contact with a copper ingot (rolled material) as described later, and the surface temperature becomes the highest. Therefore, by providing a nozzle with a large flow rate at the exit portion of the rolling roll, the exit portion of the rolling roll can be effectively cooled, and the surface temperature of the rolling roll can be lowered overall, so that a high cooling effect is obtained. Can do. In addition, the exit part of the rolling roll as used in the field of this invention is a part which faces the downstream side in a rolling roll, and is a location immediately after contact with the copper ingot (rolled material) which passed. Specifically, in FIG. 2 or FIG. 3, it is a portion indicated by oblique lines from the upper left to the lower right of the rolling roll 2.

  The method for producing copper for wire rod according to the second aspect of the present invention is a method for continuously rolling a copper ingot, and the stands of rolling rolls are arranged in multiple stages from the upstream side to which the copper ingot is supplied. And, disposing the descaler at least at one position between the stands, spraying the lubricant at a high pressure on the surface of the rolled material rolled by the upstream rolling roller, and removing the copper oxide on the surface of the rolled material. Features.

  According to this manufacturing method, the coarse copper oxide particle which exists in the surface vicinity of the copper for wire rods can be reduced as a result by removing the copper oxide on the surface of a rolling material with the scaler arrange | positioned between stands. The pressure of the lubricant sprayed from the descaler is not particularly limited, but is preferably 10 MPa or more and 14 MPa or less. In addition, since the descaler sprays lubricant directly on the rolled material, if it is placed between all stands, the temperature of the rolled material may be excessively lowered, which may make it difficult to perform the downstream rolling process. There is. Therefore, it is preferable to dispose the descaler between the stands on the downstream side rather than the upstream side in consideration of the capability of the rolling mill.

  In at least one stand in the first and second manufacturing methods, the surface of the rolling roll is preferably shot blasted.

  By subjecting the surface of the rolling roll to shot blasting, irregularities are formed on the surface of the rolling roll, and the lubricant is held on the irregularities, thereby making it difficult for copper to adhere to the rolling roll. Further, the projection material used for the shot blasting is not particularly limited, but it is preferable to use one having a particle size of 0.45 mm or more and 2 mm or less. When the particle size of the projecting material is less than 0.45 mm, the unevenness of the surface of the rolling roll is liable to be loosened, and when it exceeds 2 mm, cracks may occur on the surface of the rolling roll.

  In addition, as the lubricant in the present invention, commercially available solubil oil can be used. Soluble oils include those based on mineral oils or synthetic oils, but it is preferable to use solubil oils based on synthetic oils in terms of cooling ability.

  The copper for wire rod according to the present invention has few coarse copper oxide particles in the vicinity of the surface, and can reduce the occurrence of defects such as defects and cracks on the surface of the copper wire. Moreover, the manufacturing method of copper for wire rods of this invention can reduce the coarse copper oxide particle which exists in the surface vicinity of copper for wire rods.

Example 1
Using a multi-stage rolling mill, various coppers for wire rods were manufactured by changing manufacturing conditions such as the presence / absence of a displacer, the presence / absence of shot blasting, and the flow rate of lubricant from a nozzle. Moreover, it evaluated about each manufactured copper for wires.

<Manufacture of copper for wire>
1-4 is a figure for demonstrating the multi-high rolling mill used for embodiment of this invention. The multi-stage rolling mill M includes a plurality of stands 1 having a pair of rolling rolls 2 in a cover 3. The multi-stage rolling mill M has a supply port 31 for supplying a copper ingot C produced from a continuous casting machine (not shown), and the copper ingot C is continuously rolled by a rolling roll 2. There is a delivery port 32 for delivering the obtained copper W for wire rod, and the copper W for wire rod delivered from the delivery port 32 is wound up by a winder (not shown).

  The stands 1a to 1n are arranged in multiple stages from the upstream side where the supply port 31 is located toward the downstream side where the delivery port 32 is located. Moreover, each rolling roll 2a-2n provided in the stands 1a-1n continuously rolls the rolled material rolled by the copper ingot C or the rolling roll from the upstream side toward the downstream side, and finally the wire rod The copper W is adjusted so as to have a predetermined wire diameter φ (here, φ = 8 mm). Here, among the rolling rolls 2a to 2n, the rolling rolls 2a, 2c, 2e, 2g, 2i, 2k, and 2m are vertical rolling rolls that roll in the vertical direction, and the rolling rolls 2b, 2d, 2f, 2h, 2j , 2l and 2n are horizontal rolling rolls that roll in the horizontal direction. In addition, in FIG. 1, the arrow shows the rotation direction of each rolling roll.

  Each rolling roll 2 is provided with a nozzle N for spraying lubricant onto the rolling roll 2 as shown in FIG. 2 and 3 show a state in which a plurality of nozzles N1 to N3 are arranged in the circumferential direction of the rolling roll 2, and FIG. 4 shows a state in which one nozzle N is arranged for the rolling roll 2. Each nozzle N is supplied with a lubricant from a lubricant supply pipe, and the flow rate of the lubricant sprayed from each nozzle N to the rolling roll 2 is a pressure control valve (here) Then, the pressure is fixed at 0.5 MPa) and the diameter of the injection port of each nozzle N is determined. Here, when arranging a plurality of nozzles, each nozzle N is connected to the lubricant supply pipe via a branch pipe. In FIG. 2, the nozzle axis of each nozzle N coincides with the normal direction of the rolling roll surface, and in FIGS. 3 and 4, the nozzle axis of each nozzle N coincides with the tangential direction of the rolling roll surface. . The lubricant used was a soluble oil based on synthetic oil.

<Production conditions>
Manufacturing conditions were various conditions described in Table 1. Hereinafter, various conditions will be described in detail.

(Presence / absence of displacer)
The descaler is an apparatus that is disposed between the stands and sprays lubricant at a high pressure on the surface of the rolled material R (see FIGS. 2 to 4) rolled by the upstream rolling roller to remove copper oxide on the surface of the rolled material. It is. Here, the disc scaler sprays a lubricant onto the rolled material, and is different from the above-described nozzle that sprays the lubricant onto the rolling roll. In Table 1, in the “Disceller Placement” column, the “Position (st)” column indicates the presence / absence and location of the displacer, and the “Pressure (MPa)” column indicates the pressure of the lubricant sprayed from the discerer. Respectively. If there is a circle in the column “ac” of “Position (st)”, this indicates that the descalers are arranged at a total of three positions between the stands 1a and 1b, 1b and 1c, and 1c and 1d. On the other hand, if there is a circle in the “f-l” column of “position (st)”, stands 1f and 1g, 1g and 1h, 1h and 1i, 1i and 1j, 1j and 1k, 1k and 1l, and 1l This shows that the descalers were placed at a total of 7 locations between 1m and 1m. When the “position (st)” column is blank, it indicates that no descaler is arranged. In the “pressure (MPa)” column, a circle indicates that the lubricant was sprayed at that pressure value.

(With or without shot blasting)
The shot blasting process is a process in which a projection material collides with the surface of the rolling roll 2 to form irregularities on the surface of the rolling roll. In Table 1, in the “Presence / absence of shot blasting” column, the “Position (st)” column is the presence / absence and position of shot blasting on the surface of the rolling roll, and the “Particle size (mm)” column is shot. It represents the particle size of the projection material used when blasting. When the “position (st)” column “a-h” has a circle, it indicates that only the rolls 2a to 2h are subjected to shot blasting. Next, when there is a circle in the “a-l” column of “position (st)”, it indicates that only the rolls 2a to 2l have been subjected to shot blasting. Next, when there is a circle in the “position” column of “position (st)”, this indicates that the rolls 2a to 2n, that is, all the surfaces of the roll 2 have been shot blasted. In addition, when the column of “position (st)” is blank, it indicates that none of the rolling rolls has been subjected to shot blasting. In addition, a circle in the column of “particle size (mm)” indicates that a projection material having the particle size was used. Here, steel shot was used as the projection material.

(Lubricant flow rate from nozzle)
Except for the condition No. 1, a plurality of nozzles N1 to N3 were arranged in the circumferential direction of the rolling roll 2. In Table 1, in the “Lubricant flow rate from nozzle” column, the “Nozzle shaft angle (°)” column indicates the orientation of each nozzle with respect to the roll surface, “Flow rate at outlet (L / min)”. The column of each represents the flow volume of the lubricant in the nozzle provided so that a lubricant may be sprayed on the exit part of a rolling roll among several nozzles. When the “90” column of “Nozzle axis angle (°)” has a circle, it indicates that each nozzle is installed so that the nozzle axis coincides with the tangential direction of the surface of the rolling roll (see FIG. 3). ). At this time, the diameters of the nozzles of the nozzles N1 to N3 are different for each rolling roll, but all are the same at 3.4 to 5.2 mm, and the flow rate of the lubricant at each nozzle N1 to N3 is about 32 to 50 L / min. Met. Further, by providing the nozzle shaft so as to coincide with the tangential direction of the surface of the rolling roll, it is easy to scrape off the copper adhering to the surface of the rolling roll, and an improvement in the cleaning effect on the rolling roll can be expected.

  On the other hand, when there is a circle in the “0” column of “Nozzle axis angle (°)”, this indicates that each nozzle was installed so that the nozzle axis coincided with the normal direction of the surface of the roll (see FIG. 2). At this time, as shown in FIG. 2, the diameter of the nozzle N1 provided at the outlet of the rolling roll 2 is larger than those of the other nozzles N2 and N3. Specifically, the diameter of the nozzle N1 was 7.2 mm, the diameter of the nozzles N2 and N3 was 3.4 to 4.8 mm, and the flow rate of the lubricant in the nozzle N1 was about 70 L / min. In addition, the nozzle shaft is provided so as to coincide with the normal direction of the surface of the rolling roll, and by increasing the flow rate of the nozzle N1, the exit portion of the rolling roll can be effectively cooled, and the cooling effect on the rolling roll can be improved. I can expect.

  “○” in the “<64” column of “Flow rate (L / min)” indicates that the flow rate of the lubricant in the nozzle N1 is less than 64 L / min, and “○” in the “> 64” column. In some cases, the flow rate of the lubricant in the nozzle N1 is greater than 64 L / min.

  In condition No. 1, one nozzle N was disposed in the circumferential direction of the rolling roll 2, and the nozzle shaft was installed so as to coincide with the tangential direction of the rolling roll surface (see FIG. 4). At this time, as shown in FIG. 4, the nozzle N is not installed so as to spray the lubricant directly onto the exit portion of the rolling roll 2. Further, the flow rate of the lubricant in the nozzle N was about 60 L / min.

  In addition, the inventors removed a part of the cover 3 of the multi-stage rolling mill M during the production of copper for wire rods, and visually observed the surface of the rolling roll 2 to obtain a plurality in the circumferential direction of the rolling roll 2. In conditions No. 2 to No. 10 in which the nozzles N1 to N3 were arranged, copper was not attached to the surface of the rolling roll, and seizure to the rolling roll was prevented. In conditions No. 2 to No. 10, the surface temperature at the biting portion of the rolling roll was lowered to the extent that it was touched by hand, and all were 60 ° C. or less. In particular, the conditions No. 9 and No. 10 have a higher cooling effect on the rolling roll than the conditions No. 2 to No. 8, and the surface temperature at the biting portion of the rolling roll is about 50 ° C. It was. In contrast, in condition No. 1 in which one nozzle N was arranged in the circumferential direction of the rolling roll 2, copper adhered to the surface of the rolling roll, and seizure to the rolling roll was observed. In condition No. 1, the surface temperature at the biting portion of the rolling roll was so hot that it could not be touched by hand, and was over 80 ° C.

<Evaluation of copper for wire rod>
5 tons (5000 kg) of wire copper was produced under the conditions of No. 1 to No. 10 listed in Table 1, and the copper for wire rods produced under each condition were sample Nos. 1-1 to 1-10, respectively. It was. And about each sample No.1-1-No.1-10, the cross-section of arbitrary three places was observed and the coarse copper oxide particle which exists in the surface vicinity was measured.

  Specifically, the sample was cut every 1 m from the end, and a total of three cross sections were observed. The cross section was observed in an annular region within 100 μm from the surface, and the number of copper oxide particles having a maximum diameter of 10 μm or more existing in the region was measured. Moreover, the scanning electron microscope (SEM) or the optical microscope was used for observation of a cross section. The average number of copper oxide particles having a maximum diameter of 10 μm or more when observing the cross section at three locations (hereinafter referred to as the average number) and the location having the largest number of copper oxide particles having a maximum diameter of 10 μm or more among the three locations. Table 2 shows the number of copper oxide particles having a maximum diameter of 10 μm or more (hereinafter referred to as the maximum number).

  As is clear from the results in Table 2, Sample Nos. 1-2 to 1-10 have fewer copper oxide particles with a maximum diameter of 10 μm or more than Sample No. 1-1 and have a maximum diameter of 10 μm or more. The average number of copper oxide particles was 15 or less.

(Example 2)
In the same manner as in Example 1, copper for wire rods was manufactured under the conditions No. 1, No. 2, and No. 9 listed in Table 1, and the copper for wire rods manufactured under each condition was sample No. 2. -1 to No.2-4. However, No. 2-1 and No. 2-2 were the same conditions (No. 1). Further, in the same manner as in Example 1, for each of samples No. 2-1 to No. 2-4, the cross sections of arbitrary three locations were observed, and the average of copper oxide particles having a maximum diameter of 10 μm or more existing in the vicinity of the surface The number and maximum number were measured. The results are shown in Table 3.

<Torsion test>
Next, a twist test was performed on each of samples No. 2-1 to No. 2-4, and the amount of copper powder generated by the twist test was measured.

  In the torsion test, as shown in FIG. 5, a test piece S having a length of 300 mm or more obtained by cutting a sample is prepared, and the test piece S is gripped at two locations with an interval of 300 mm. After being twisted 20 times in this state, the original state was restored. Then, after wiping the surface of the test piece S with a cloth after the twist test, the amount of copper powder generated by the twist test was determined from the weight difference between the test piece S before and after the twist test. The results are shown in Table 3.

  As is apparent from the results in Table 3, Samples No. 2-1 and No. 2-2, in which the average number of copper oxide particles having a maximum diameter of 10 μm or more exceeds 15, have a copper powder generation amount of 15 mg or more, Copper powder is easily generated. In contrast, Samples No. 2-3 and No. 2-4, in which the average number of copper oxide particles having a maximum diameter of 10 μm or more is 15 or less, are compared with Samples No. 2-1 and No. 2-2. It can be seen that the amount of copper powder generated is small and copper powder is hardly generated. Therefore, it is thought that copper for wire rods with a small number of copper oxide particles having a maximum diameter of 10 μm or more can suppress copper powder generated when wire drawing.

  From the above results, the copper for wire rods of the present invention with few coarse copper oxide particles in the vicinity of the surface can suppress the generation of copper powder when drawn, so that the surface of the copper wire is not damaged or cracked. It can be seen that the occurrence of defects can be reduced.

  Note that the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the gist of the present invention. For example, the number of nozzles arranged in the circumferential direction of the rolling roll may be increased, or the flow rate of the lubricant may be changed as appropriate.

  The copper for wire rods and the method for producing the same of the present invention can be suitably used for copper for wire rods used for copper wires of coated wires.

It is a figure for demonstrating the multi-high rolling mill used for embodiment of this invention. It is a figure which shows the state which has arrange | positioned the some nozzle in the circumferential direction of a rolling roll, and the nozzle axis | shaft of each nozzle corresponds with the normal line direction of the rolling roll surface. It is a figure which shows the state which has arrange | positioned the some nozzle in the circumferential direction of a rolling roll, and the nozzle axis | shaft of each nozzle corresponds with the tangential direction of the surface of a rolling roll. It is a figure which shows the state which has arrange | positioned one nozzle with respect to a rolling roll. It is a figure for demonstrating a twist test.

Explanation of symbols

M multi-stage rolling mill
1,1a-1n stand 2,2a-2n Roll
3 Cover 31 Supply port 32 Outlet
N, N1-N3 nozzle
C Copper ingot R Rolled material W Copper for wire rod S Specimen

Claims (8)

  Copper for wire rods produced by continuously rolling copper ingots. When observing the cross-sections at any three locations, an average of 15 copper oxide particles with a maximum diameter of 10 μm or more existing in a region within 100 μm from the surface Copper for wire rod characterized by the following.   2. The wire rod according to claim 1, wherein the number of copper oxide particles having a maximum diameter of 10 μm or more is a maximum of 20 or less in any of three arbitrary locations where the copper oxide particles having a maximum diameter of 10 μm or more are the largest. copper.   The copper for wire according to claim 1, wherein the number of copper oxide particles having a maximum diameter of 10 µm or more is 15 or less at all three arbitrary locations.   A method for producing copper for a wire rod, in which a copper ingot is continuously rolled, wherein rolling roll stands are arranged in multiple stages from an upstream side to which the copper ingot is supplied, and the rolling roll is bitten in at least one stand. A method for producing copper for a wire rod, comprising rolling at a roll surface temperature of 60 ° C. or less at the recessed portion.   The plurality of nozzles are arranged in a circumferential direction of the rolling roll, and the adjustment of the roll surface temperature in the rolling roll is performed by spraying a lubricant from the plurality of nozzles onto the rolling roll. For producing copper for wire.   6. The wire according to claim 5, wherein at least one of the plurality of nozzles is installed so as to spray a lubricant onto an exit portion of the rolling roll, and a flow rate of the lubricant is set to exceed 64 L / min. For manufacturing copper.   A method for producing copper for wire rods for continuously rolling a copper ingot, wherein the roll roll stands are arranged in multiple stages from the upstream side to which the copper ingot is supplied, and a descaler is disposed at least at one location between the stands. The copper is removed from the surface of the rolled material by spraying a lubricant at a high pressure on the surface of the rolled material that has been rolled by the rolling roller on the upstream side of the descaler. .   The method for producing copper for wire rod according to any one of claims 4 to 7, wherein the surface of the rolling roll is shot blasted in the at least one stand.

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