JP2013047379A - Method for producing oxygen-free copper rod - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an oxygen-free copper rod, which allows the production of a copper rod having a low oxygen content and not adhering even if a mutual contact state of copper wire materials is maintained.SOLUTION: A thick copper rod 31 with a large diameter is formed by allowing a copper seed wire to traverse a coating chamber 6, connected with a holding furnace 5 holding molten copper, to stick the molten copper on the surface of the seed wire. The oxygen-free copper rod is prepared by sequentially subjecting the copper rod to cooling, hot rolling, recooling, and winding steps. The temperature of the holding furnace for keeping the molten copper warm is 1,140 to 1,180°C, and the temperature of the copper rod stuck with the molten copper before entering the hot rolling step after being cooled is 600 to 800°C. The temperature during winding is higher than room temperature and lower than 100°C. Thereby, a high quality copper wire material having an oxygen content of 2-10 ppm is produced. Further, mutual adhering of the wire materials is suppressed in an annealing step during winding by forming a specific oxide film.

Description

  The present invention relates to a method for producing a copper rod, and specifically relates to a method for producing an oxygen-free copper rod. Oxygen-free copper rods manufactured by this method have characteristics such as high electrical conductivity, low oxygen content, and high tensile rate, and are mainly used in wind power generation, nuclear power generation, high-speed rail, in-vehicle conductors, It can be used in fields where high quality is required for copper rods, such as high-voltage electric wires.

  Currently, wind power generation is the cleanest and safest power generation technology, which is being introduced more rapidly than other new energy worldwide, and may become one of the major power sources in the future. China Wind Energy Association forecasts that the total installed capacity of Chinese wind power will reach 8 billion watts in 2020, 18 billion watts in 2030, and 50 billion watts in 2050 . The Chinese government will actively promote the construction of smart grids and solve the transmission problem in wind power generation. In the future, wind power will become one of China's main power sources.

  At the same time, China is focusing on the priority development of high-speed railways as an emerging industry in the “Twelfth Five-Year Plan”. By 2010, the operating mileage of China Railway has reached 91,000 kilometers and the operational mileage of high-speed railway has reached 8358 kilometers. However, this is just the beginning. According to the forecast, by the end of the 12th Five-Year Plan (2015), China Railway's operating mileage has reached more than 120,000 kilometers, of which high-speed railways It is expected to reach more than 16,000 kilometers.

  In power generation units, transformers, traction motors, trolley wires, etc. used in the above industries, high-quality magnet wires are used in large quantities. The main quality indicators for magnet wires include tensile strength, stretch ratio, electrical conductivity, pressure resistance, oxygen content and surface quality, of which oxygen content is one of the main indicators. If the oxygen content of the copper rod, which is the raw material of the magnet wire, is too high, the following phenomenon occurs.

1) The oxygen in the copper rod is in the state of copper oxide, and when viewed from the crystal phase structure, copper oxide is present near the boundaries of the crystal grains. Copper oxide appears as a mixed form at the crystal interface and adversely affects the toughness of the material. For this reason, the mechanical performance of the copper rod is lowered, and a tearing phenomenon occurs in the subsequent processing steps.
2) The conductivity of the copper rod is reduced due to the presence of copper oxide.
3) Copper products after processing generate bubbles and pinholes when annealed in hydrogen, deteriorating the surface quality.
4) If there is a defect on the surface of the product due to the generation of these bubbles or pinholes, the high-pressure resistance is reduced.

  Here, the oxygen content of the low-oxygen copper rod produced by continuous casting continuous rolling currently on the market is 200 to 400 ppm, and the oxygen content of the oxygen-free copper rod produced by the pulling continuous casting technique is 10 to 20 ppm, both of which have a high oxygen content.

  In the conventional method of manufacturing a coated metal wire, for example, there is a dip forming method in which a bus bar (seed wire) is immersed in a coating material such as a molten copper or a molten copper alloy, and the coating material is attached to the surface of the bus bar. is there. In this method, a covering material is attached by inserting a bus bar from the bottom (downward) of the crucible holding the molten metal and pulling it out from above (for example, see Patent Document 1).

  The Dip Forming method described in Patent Document 2 is an invention related to an adhesion crucible. The purpose is to solve the unevenness of the copper alloy layer on the surface of the bus bar. Under the temperature conditions described in the examples, the temperature of the melting furnace is 1160 ° C.

  The Dip Forming method described in Patent Document 3 is an invention for enhancing the strength and wear resistance of a wire. The busbar is continuously adhered with molten copper or copper alloy, then hot rolled at a rolling ratio of 10% to 40% under a temperature condition of 750 ° C to 850 ° C to form a metal bond between the busbar and the molten metal. To increase the strength and wear resistance of the wire.

  The Dip Forming method described in Patent Document 4 is an invention that improves the electrical conductivity and bending resistance of a wire by a method in which a copper alloy is continuously adhered and cast onto a bus bar using a special crucible. The temperature conditions described in the examples are such that the temperature of the molten metal in the melting furnace is around 1150 ° C., and the temperature before the rolling process is around 800 ° C.

Japanese Patent Publication No.49-39740 JP 57-68263 A Japanese Patent Publication No.2-11460 JP-A-60-261658

  However, even when manufactured using the Dip Forming method under the temperature conditions described in Patent Documents 1 to 4, the copper wire after winding has a problem that variation in oxygen content distribution occurs. For example, when the oxygen content of the wire is too high, there is a problem that bubbles are formed at the welding point when the copper wire is welded to a specific position.

  Moreover, in the annealing process at the time of winding the copper wire after winding (when bobbing and annealing), there arises a problem that the wires stick to each other. This is a problem peculiar to copper wires produced by the Dip Forming method with extremely low oxygen content.

  In particular, a copper wire material for in-vehicle electronic components is required to have a high-quality wire having a good surface condition as well as a low oxygen content for satisfying the requirement for welding to a specific position.

  The present invention has been made in view of the above points, and overcomes the defect of high oxygen content in copper rods made by current manufacturing techniques, and maintains low oxygen content and the state in which copper wires are in contact with each other. It aims at providing the manufacturing method of an oxygen free copper rod which does not adhere even if it is.

  In order to achieve the object of the present invention, the present invention employs the following technical method for producing an oxygen-free copper rod. After the copper material is heated in a drying furnace, it is put into a melting furnace and melted. The molten metal after melting flows into the holding furnace through the runner and is kept warm. One continuous thin copper rod seed wire is passed through an adhesion chamber communicating with a holding furnace, and a molten metal is adhered to the surface of the copper rod seed wire to form a large-diameter copper rod. Then, after performing cooling, hot rolling, recooling, and a winding process in order, the oxygen-free copper rod of arbitrary lengths with high electrical conductivity, a low oxygen content, and a high tensile rate is obtained. The temperature of the holding furnace that keeps the molten metal to be attached to the surface of the copper rod seed wire is 1140 to 1180 ° C, and the copper rod formed by adhering the molten metal to the copper rod seed wire is cooled and then hot rolled. The temperature before entering is 600 to 800 ° C, and the temperature at winding is higher than room temperature and lower than 100 ° C.

  Preferably, the temperature during winding is 45 ° C. or higher and 80 ° C. or lower.

  Preferably, the molten metal surface of the melting furnace is covered with a floating material for blocking air intrusion. Furthermore, this floating material is carbon. In particular, the carbon has a thickness of 100 to 300 mm.

  Preferably, the temperature of the molten metal in the melting furnace is controlled between 1140 ° C and 1180 ° C, and the furnace is filled with a protective reducing gas.

  Preferably, the holding furnace is filled with a protective reducing gas.

  Preferably, a ceramic partition wall having a lower end lower by 100 to 200 mm than the liquid level of the molten metal is provided near the runner inside the melting furnace.

  Preferably, the inside of the adhesion chamber is filled with a protective reducing gas.

  Preferably, the copper rod seed wire is subjected to a skinning process before entering the adhesion chamber. The copper rod seed line to be peeled is a multilayer copper rod obtained by performing the step of completing the oxygen-free copper rod at least twice.

  Preferably, in the cooling treatment, the copper rod is passed through a cooling chamber. The inside of the cooling chamber is filled with protective reducing gas.

Preferably, the protective reducing gas is a mixture gas of _{N 2,} H 2, _{O 2,} volume concentration of 0.5% to 4.5% of _{H 2, O 2} concentration is less than 20 ppm, remainder _{N 2} It is.

  Preferably, deposits on the copper material (copper plate) are removed before the copper material (copper plate) is heated in the drying furnace.

  The present invention is obtained after using a continuous thin copper rod as a substrate seed line (copper rod seed line) and attaching a molten copper to the surface of the copper rod seed line using a dip forming method. The large-diameter copper rod seed wire is subjected to cooling, hot rolling, recooling, and winding processes in order. This completes an oxygen free copper rod, that is, an oxygen free rod is manufactured. Oxygen-free copper rods manufactured by this method have any length, high conductivity, low oxygen content (2 ppm to 10 ppm), and high tensile rate, so wind power generation, nuclear power generation, high-speed rail, in-vehicle It can be used in fields where high quality is required for copper rods, such as conducting wires and ultra high voltage electric wires.

  In the present invention, the surface of the melting furnace is covered with a floating material for blocking the intrusion of air into the molten metal, and the content of oxygen does not increase even if the copper material (copper plate) is charged into the melting furnace in several steps. I did it. In addition, by separating the adhesion chamber from the melting furnace, guaranteeing the stability of the adhesion condition of the molten metal, and suppressing the influence on the adhesion process due to multiple injections of materials, it was possible to produce oxygen-free copper rods continuously.

  According to the present invention, it is possible to overcome the defect that the oxygen content is high, and to realize a copper rod that has a low oxygen content and does not stick even if the copper wires are kept in contact with each other.

Schematic of a production line in a method for producing an oxygen-free copper rod according to an embodiment of the present invention Schematic of a combination furnace in a method for producing an oxygen-free copper rod according to an embodiment of the present invention Sectional drawing of the combination furnace shown in FIG. Schematic of the adhesion chamber in the manufacturing method of an oxygen free copper rod concerning an embodiment of the invention The schematic diagram for demonstrating the outline | summary of the manufacturing method of the oxygen-free copper rod which concerns on embodiment of this invention.

  Hereinafter, the present invention will be described in combination with the drawings. The present invention discloses a method for producing an oxygen-free copper rod. Copper rods manufactured by conventional manufacturing methods have a high oxygen content. In the production method of the present invention, the copper material dried by heating is melted, the molten metal is held in a holding furnace, one seed wire is passed through an adhesion chamber communicating with the holding furnace, and the molten metal is placed on the surface of the copper rod. A large diameter copper rod is formed by adhering.

  The manufacturing method of the oxygen-free copper rod according to the embodiment of the present invention is as follows.

  The copper material (copper plate) heated in the drying furnace is divided into multiple times (in the implementation process of the method, according to the amount of molten metal decreased, the copper material is added and the raw material is replenished in a timely manner). Add and dissolve. The molten metal flows into the holding furnace through a runner (can be made with a crucible) and is kept warm. A thin copper rod seed wire is passed through an adhesion chamber that communicates with the holding furnace. Thereby, the molten copper adheres to the surface of the copper rod seed wire, and a copper rod having a larger diameter than the copper rod seed wire is formed. The copper rod is subjected to cooling, hot rolling, recooling, and winding treatment in order to produce an oxygen-free copper rod of any length with high conductivity, low oxygen content, and high tensile rate.

  The temperature of the holding furnace for keeping the molten copper is 1140 ° C to 1180 ° C. Moreover, the temperature before the copper rod seed wire to which the molten metal has adhered enters the hot rolling process after cooling is 600 ° C to 800 ° C. Furthermore, the temperature at the time of winding the copper rod is higher than room temperature and lower than 100 ° C. Preferably, the temperature during winding is controlled between 45 ° C and 80 ° C.

  The heat source used for heating in the present invention is an electric heating method or a gas heating method. By using the above temperature control management technique, in this embodiment, an oxygen-free copper rod that is a high-quality copper wire having an oxygen content of 2 ppm to 10 ppm can be manufactured.

  Moreover, this invention can form a specific oxide film on the surface of a copper rod by utilizing the temperature control technique mentioned above. For this reason, in the annealing process at the time of subsequent winding, not only can the copper wire rods of the copper rods be prevented from sticking to each other, but also the surface is not damaged or disconnected. Therefore, a high-quality oxygen-free copper rod having a good surface state can be produced.

  When the winding temperature exceeds the above range, a thick oxide film is formed on the surface of the copper rod due to a rapid oxidation reaction, and the surface is damaged or broken during processing, so that the surface condition is poor. It becomes an oxygen copper rod. Thereby, an oxygen-free copper rod having a desired oxygen content cannot be obtained.

  Moreover, when the temperature at the time of winding is less than said range, an oxide film cannot be formed on the surface of a copper rod. Therefore, in the subsequent annealing process at the time of winding the copper rod, the copper wire of the copper rod adheres to each other to form an oxygen-free copper rod having a poor surface state, and also to obtain a desired high-quality oxygen-free copper rod wire Can not.

  Thus, in this embodiment, by controlling the temperature at the time of winding the copper rod to be higher than room temperature, a very small amount of oxidation reaction is generated, and the problem of mutual adhesion between the wires in the copper rod is solved. Solve.

  According to the manufacturing method in the present embodiment, an oxygen-free copper rod which is a copper wire having an oxygen content of 2 ppm to 10 ppm can be manufactured. This oxygen-free copper rod is used particularly for in-vehicle electronic components.

  That is, when the oxygen content exceeds the above range (2 ppm to 10 ppm), not only bubbles are generated during the welding process, but also a thick oxide film is formed on the surface of the copper rod. For this reason, in a copper rod, a damage | wound or disconnection generate | occur | produces in the case of a process, and it becomes an oxygen free copper rod with a bad surface state. Therefore, when the oxygen content exceeds the above range (2 ppm to 10 ppm), it cannot be used for an on-vehicle electronic component in which a high-quality wire having a good surface condition and the like is strictly required.

  In addition, if it falls below the above range (2 ppm to 10 ppm), an oxide film cannot be formed on the surface of the copper rod, and the copper wire rods of the copper rod stick to each other in the annealing process after winding. And it becomes an oxygen-free copper rod having a poor surface condition. As a result, when the oxygen content is below the range of 2 ppm to 10 ppm, as in the case of the range above 2 ppm to 10 ppm, it is used for in-vehicle electronic components where high quality wire with good surface condition is strictly required Can not.

  As a further improvement plan of such a technical plan and a supplement thereto, the embodiment according to the present invention may further include additional technical features described below. As a result, in the embodiment of the present invention, it is possible to incorporate the above-described technical solution according to a specific action.

  First, in order to control the oxygen concentration and suppress the sticking phenomenon, the temperature during winding is 45 ° C. or higher and 80 ° C. or lower.

  Second, the surface of the molten metal of the melting furnace is covered with a floating material for blocking air intrusion. Further, this floating material is carbon, and in particular, the thickness of carbon is 100 to 300 mm.

  Third, the temperature of the molten metal in the melting furnace is controlled between 1140 ° C and 1180 ° C, and the furnace is filled with protective reducing gas.

  Fourth, the holding furnace is filled with a reducing gas for protection.

  Fifth, a ceramic partition wall having a lower end lower by 100 to 200 mm than the melt surface is provided near the runner inside the melting furnace.

  Sixth, the inside of the adhesion chamber (which can be made with a crucible) is filled with protective reducing gas.

  Seventh, the copper rod seed wire is stripped before passing through the adhesion chamber.

Eighth, the reducing protective gas _is mixed gas of N _2, H 2, _{O 2,} the volume concentration of _{H 2} is set to 0.5% ~4.5%, _{O 2} concentration in 20ppm or less, the remainder to _{N 2} .

  Ninth, before heating the copper material (copper plate) in the drying furnace, the deposits (copper oxide grains, patina, etc.) on the copper material (copper plate) are removed.

The technical means of the present invention realizes the object of the invention by utilizing the following mechanism.
(1) Copper material (copper plate, the higher the purity of copper, the better) is that after surface heating and dust removal treatment, impurities and moisture on the surface are removed, and after charging into the melting furnace, the water undergoes the following chemical reaction under high temperature conditions. To prevent.

2H ₂ O = 2H ₂ + O ₂
When oxygen decomposed from this reaction is dissolved in the molten metal, the oxygen content of the molten metal is increased.
The following series of chemical reactions occur in the carbon and protective reducing gas in the melting furnace.

2Cu + O ₂ = 2CuO
2C + O ₂ = 2CO
2H ₂ + O ₂ = 2H ₂ O
2CuO + CO + H ₂ = 2Cu + H ₂ O + O ₂
By these reactions, the oxygen content in the molten metal is reduced. The thickness of the carbon layer directly affects the oxygen content of the melt. When the thickness of the carbon layer is insufficient, the reduction reaction becomes insufficient due to the lack of CO in the gas inside the melting furnace. On the other hand, if it is too thick, H ₂ cannot smoothly come into contact with the molten metal, and similarly, the reduction reaction becomes insufficient and the oxygen content of the molten metal cannot be effectively reduced.

(2) The molten metal flows from the runner below the liquid level into the sealed holding furnace, and then flows into the deposition chamber (crucible) communicating with the holding furnace. The inside of the holding furnace is filled with a protective gas composed of 0.5% to 4.5% H ₂ and a large amount of N ₂ , and the following chemical reaction occurs.

2H ₂ + O ₂ = 2H ₂ O
CuO + H ₂ = Cu + H ₂ O
By these reactions, the oxygen content in the molten metal is further reduced.

  The action of the ceramic partition inside the holding furnace is to prevent copper slag floating on the surface of the holding furnace from flowing into the adhesion chamber and adhering to the surface of the copper rod seed wire, affecting the surface quality. Corundum ceramic material is used as the material.

(3) A thin copper rod seed wire is passed from the bottom of the deposition chamber communicating with the holding furnace, and a large diameter copper rod is formed by adhering the molten metal to the surface of the copper rod seed wire. The deposition chamber is also filled with a large amount of protective gas composed of N ₂ containing 0.5% to 4.5% H ₂ , causing a reduction reaction and simultaneously isolating oxygen in the air. Before the copper rod seed line passes through the bottom of the deposition chamber, a skinning process (skinning is a process of removing a layer having a high oxygen content on the surface of the copper rod seed line) is performed. Thereby, it is possible to keep the oxygen content of the copper rod seed line before the copper melt adheres to the lowest state, and to ensure that a copper rod having a low oxygen content is finally produced.

  (4) The copper rod is continuously cooled in the cooling chamber above the deposition chamber. In the cooling chamber, the amount of cooling water in each cooling segment is adjusted to control the crystal speed of the copper rod.

Since the cooling chamber is filled with a large amount of protective gas composed of N ₂ containing 0.5% to 4.5% of H ₂ , the following chemical reaction occurs in this treatment.

2H ₂ O = 2H ₂ + O ₂
2Cu + O ₂ = 2CuO
CuO + H ₂ = Cu + H ₂ O
The action of the protective gas is to prevent oxygen decomposed from the cooling water from entering the copper rod at a high temperature and prevent an increase in the oxygen content of the copper rod.

(5) The copper rod after cooling is put into a rolling mill and the surface is rolled. Since the temperature of the copper rod after cooling and before entering the rolling mill becomes 600 to 800 ° C., in order to prevent an oxidation reaction in a high temperature state, 0.5% to 4.5% H ₂ is also provided inside the rolling mill as in the cooling chamber. It is necessary to fill a protective gas composed of a large amount of N ₂ containing.

  (6) The copper rod after the rolling process is cooled again and coiled by the winding device, but the surface temperature of the copper rod before entering the winding device is controlled to be higher than room temperature and lower than 100 ° C. The Further, it is preferably controlled between 45 ° C. and 80 ° C. This temperature control technology makes it possible to produce high-quality copper wires (oxygen-free copper rods) with an oxygen content of 2 ppm to 10 ppm. That is, the surface temperature of the copper rod immediately after winding by the winding device is controlled in a range higher than room temperature and lower than 100 ° C. The surface temperature of the copper rod immediately after winding is preferably controlled between 45 ° C. and 80 ° C.

  Moreover, in this Embodiment, a specific oxide film is formed in the surface of a copper rod by utilizing said temperature control technique. For this reason, in the annealing process at the time of winding up a copper rod after oxide film formation, not only can the wire rods of the copper rods be prevented from sticking to each other, but also the surface will not be scratched or broken. For this reason, it is possible to produce a high-quality oxygen-free copper rod having a good surface condition.

  When the temperature at the time of winding exceeds the above range, a thick oxide film is formed on the surface of the copper rod by a rapid oxidation reaction. For this reason, scratches or disconnections occur during processing, resulting in an oxygen-free copper rod having a poor surface state, and a copper wire having a desired oxygen content cannot be obtained.

  Moreover, when the temperature at the time of winding is less than said range, an oxide film cannot be formed on the surface of a copper rod. For this reason, in the annealing process at the time of subsequent winding, the wire materials adhere to each other, resulting in an oxygen-free copper rod having a poor surface state, and a desired high-quality copper wire material cannot be obtained. Therefore, by controlling the winding temperature to be higher than room temperature, an extremely small amount of oxidation reaction is generated on the surface of the copper rod, thereby solving the problem of mutual adhesion of the wires on the copper rod.

  Hereinafter, a method for manufacturing an oxygen-free copper rod according to an embodiment of the present invention will be described with reference to a schematic diagram of a production line shown in FIG.

  After being processed, the copper plate 26 (see FIG. 3) is put into the melting furnace 4 by the copper material supply roller 1, the supply carriage 2, and the transport roller 3, and is melted by heating. Since the level of the molten metal in the melting furnace 4 is relatively high, the molten metal flows into the holding furnace 5 that communicates with the melting furnace 4. Since the holding furnace 5 passes through the adjacent deposition chamber 6, the molten metal further flows into the deposition chamber 6 through the holding furnace 5.

  When the melting furnace 4 stops operation, the entire combined furnace (the combined furnace shown in FIG. 2 includes the melting furnace 4, the holding furnace 5, and the adhesion chamber 6) is slightly tilted, so that the molten liquid inside the adhesion chamber 6 is obtained. The surface can be raised.

  After passing through the stripping and straightening device 18, the copper rod seed wire enters from the bottom surface of the adhesion chamber 6 and is pulled out from the upper part by the wire drawing machine 7 (see FIG. 4). If the diameter of the connecting portion of the copper rod is large and the die on the bottom surface of the adhesion chamber 6 cannot be passed, the connecting portion may be narrowed by the swaging machine 8 and then passed through the die.

  The copper rod 31 after the adhesion (see FIG. 4) passes through the pre-rolling tension controller 9 after being pulled out, enters the series rolling mill 10 with the approach speed adjusted by the tension of the copper rod by the pre-rolling tension controller 9. The series rolling mill 10 rolls the copper rod 31 and sprays the emulsion to cool it. The emulsion whose temperature has risen is subjected to heat exchange cooling with cooling water in the emulsion cooling system 14.

  After the rolling process, the copper rod 31 enters the tension controller 11 after rolling, the pulling speed is adjusted by adjusting the tension, and finally coiling is performed by the winding device 12. The coiled copper rod is conveyed to the finished product roller 13. A part of the finished product enters the seed line circulation supply device 15 as a raw material copper seed line and again enters the production process. The debris generated in the peeling process is collected by the waste wire winder 17. When it is necessary to connect separately coiled seed wires and continuously produce them, the seed wire connecting machine 16 performs connection processing.

  The melting furnace 4 is heated by the eddy current effect by the first inductor 19 and the third inductor 21 shown in FIGS. The second inductor 20 heats the holding furnace 5, and the molten metal 25 enters the adhesion chamber 6 from the holding furnace 5 through the communicating runner 22. When the copper plate 26 is charged into the combination furnace, the charging port 24 is opened. When the entire combination furnace is operated, the holding furnace lid 23 is in a closed state, and the exhaust port 27 of the furnace body is in an open state. The low level liquid level sensor 28 and the high level liquid level sensor 29 sense the state of the liquid level of the molten metal 25 of the holding furnace 5 and feed back to the control system. Thereby, it is determined whether the copper plate 26 is charged and melted or the combination furnace is tilted. Throughout the operation process of the production line, the protective reducing gas of the prepared composition is continuously injected into the inlet of each furnace, and a stable atmosphere of the protective gas or reducing gas in each furnace is ensured.

  As described above, in the method for producing an oxygen-free copper rod according to the embodiment of the present invention, as shown in FIG. 5, the copper material (copper plate) 26 is transported by the transport roller 3 and heated by the drying furnace 3a as a preheating device. To do. The heated copper plate 26 is put into the melting furnace 4 and melted. It should be noted that the amount of the copper plate 26 charged into the melting furnace 4 is adjusted to the amount of molten metal in the melting furnace 4 depending on the detection results of the low level liquid level sensor 28 and the high level liquid level sensor 29 in the melting furnace 4. Is set. The molten copper 25 in the melting furnace 4 flows into the holding furnace 5 through the runner and is kept warm.

  On the other hand, the copper rod seed line supplied as a raw material from the seed line circulation supply device 15 is corrected by the correction device 18a and the oxidized portion of the surface is shaved by the skinning device 18b, and then, as a thin copper rod seed wire, It passes through a deposition chamber 6 that communicates with the holding furnace 5. The copper rod seed wire passes through the straightening device 18 a and the skinning device 18 b, enters from the bottom surface of the adhesion chamber 6, and is drawn out from the upper portion of the adhesion chamber 6 by the wire drawing machine 7. In addition, when the diameter of the connection part of a copper rod seed wire is large and cannot pass the die | dye of the bottom face of the adhesion chamber 6, after making a connection part thin by the swaging machine 8, it passes through the adhesion chamber 6. Thereby, the molten copper is adhered to the surface of the copper rod seed wire, and the copper rod 31 having a larger diameter than the copper rod seed wire is formed.

  After the copper rod 31 after adhering is cooled by the cooling device 140, when it passes through the pre-rolling tension controller 9 (see FIG. 1), the entering speed is adjusted by the tension of the copper rod 31 and enters the series rolling mill 10. In the series rolling mill 10, the copper rod 31 is rolled, and the cooling device 32 performs heat exchange cooling with cooling water. The copper rod 31 after the rolling process passes the post-rolling tension controller 11 (see FIG. 1), and the tension of the copper rod 31 by the controller 11 is adjusted. As a result, the pulling speed is adjusted, and finally coiling is performed by the winding device 12.

  As a result, an oxygen-free copper rod having an arbitrary length with a high conductivity, a low oxygen content, and a high tensile rate is produced. The coiled copper rod is transported to the finished product roller 13 or supplied to the seed wire circulation supply device 15 as a copper rod seed wire as a raw material and enters the production process again.

  In this manufacturing method, the temperature of the holding furnace 5 for keeping the molten copper, the temperature before the molten metal is attached to the copper rod seed wire and entering the rolling process, and the temperature immediately after winding by the winding device 12 are controlled. . For example, the control unit 400 controls the temperature at which the molten copper in the holding furnace 5 is kept at 1140 ° C. to 1180 ° C. Further, the control unit 400 controls the cooling device 140 so that the temperature before the copper rod 31 enters the series rolling mill 10 in the hot rolling process after passing through the cooling device 140 becomes 600 ° C to 800 ° C. To do. Further, for example, the control unit 400 controls the cooling device 32 and the like so that the temperature immediately before the copper rod is wound by the winding device 12 is higher than room temperature and lower than 100 ° C., preferably 45 ° C. to Keep between 80 ° C.

  Thereby, the molten copper adheres to the surface of the copper rod seed wire, and a copper rod having a larger diameter than the copper rod seed wire is formed. The copper rod is subjected to cooling, hot rolling, recooling, and winding treatment in order to produce an oxygen-free copper rod of any length with high conductivity, low oxygen content, and high tensile rate. In addition, before the copper rod seed wire enters the adhesion chamber 6, at least two times or more are performed to complete the oxygen-free copper rod by performing the above-described molten metal adhesion, cooling, hot rolling, recooling, and winding processes. A multilayer copper rod formed repeatedly may be used. As a result, it is possible to realize a suitable oxygen-free copper rod in which bubbles are not generated even when the oxygen content is further reduced and welding to the terminal.

  In the following, the effects of the present invention will be described based on specific data of some specific embodiments.

<1. Example 1>
An oxygen-free copper rod was manufactured using the equipment shown in FIGS. Specifically, the copper plate 26 heated in the drying furnace was put into the melting furnace 4 in a plurality of times and melted at 1160 ° C. The molten metal that was melted flowed into the holding furnace 5 through the flow path and was kept at 1160 ° C.

  A copper rod having a diameter larger than that of the copper rod seed wire was formed by passing a thin copper rod seed wire through an adhesion chamber 6 communicating with the holding furnace 5 and adhering a molten copper to the surface of the copper rod seed wire. The copper rod seed wire was subjected to a stripping treatment to remove an oxide layer having a high oxygen content on the surface of the copper rod seed wire before passing through the adhesion chamber 6.

  Thereafter, the copper rod was sequentially cooled, hot-rolled and re-cooled. At that time, the temperature of the copper rod adhered with the molten metal before cooling and before entering the hot rolling process was 700 ° C.

  Then, the winding process was performed at the temperature of 55 degreeC.

The oxygen-containing concentration of the oxygen-free copper rod produced under the above conditions was 4 ppm. This is shown in Table 1 together with the relationship between each example of the temperature at the time of winding the copper rod, the oxygen content, and the welding state, and the comparative example.

<2. Examples 2-4, Comparative Examples 1-2>
An oxygen-free copper rod was manufactured under the same conditions as in Example 1 except that the temperature during winding of the oxygen-free copper rod was changed (see Table 1).

<3. Examples 5 to 7>
The oxygen-free copper rod was manufactured under the same conditions as in Example 1 except that when the oxygen-free copper rod was produced, the number of times shown in Table 2 was repeated for adhesion of the molten metal, cooling, hot rolling, recooling, and winding. Manufactured.

In Table 2, each example of the number of seed wire adhesion layers in a copper rod, oxygen content, and a welding state is shown.

  In addition, regarding Tables 1 and 2, with regard to “whether or not the mutual adhesion phenomenon occurred in the annealing process during winding”, ○ is an acceptable state in which adhesion has not occurred, and × is a failure in which adhesion has occurred Each state is represented.

  As for “welded state”, ◎ is a very preferable state in which no bubbles are generated at the welding point when welding the terminal and the oxygen-free copper rod, and ○ is a preferable state in which almost no bubbles are generated when welding is performed. , X represents a poor welding state in which bubbles are generated at the welding points.

  Furthermore, as the “comprehensive result”, it is preferable that the result is a very favorable result by comprehensively considering “whether the mutual adhesion phenomenon has occurred in the annealing process during winding” and “welding state”. The case of a result is indicated by ◯, and the case of a bad result is indicated by ×.

  Thereby, the oxygen-free copper rods obtained in the respective examples and comparative examples were evaluated.

  As apparent from Table 1, when the temperature at the time of winding was controlled to be higher than room temperature and lower than 100 ° C., the oxygen content of the produced oxygen-free copper rod was 2 to 10 ppm. Thereby, when welding a terminal and an oxygen free copper rod, the problem that a bubble will arise in a welding point did not generate | occur | produce.

  Moreover, in the annealing process at the time of subsequent winding, the problem that the wires sticked to each other did not occur, so the surface condition was good. Furthermore, the problem of disconnection did not occur during processing.

  In particular, when the winding temperature is 45 ° C. or more and 80 ° C. or less, the oxygen content is 2 to 5 ppm, and there is no problem that bubbles are generated when welding the terminal and the oxygen-free copper rod. Did not occur. Moreover, in the annealing process at the time of subsequent winding, the problem that the wires stick to each other did not occur, so the surface condition was very good. Furthermore, the problem of disconnection did not occur at all during processing.

  However, in Comparative Example 1, the oxygen content was 1.5 ppm, and there was no problem that bubbles were generated when welding the terminal and the oxygen-free copper rod. However, the problem that the wires stick to each other occurred, and as a result, the surface condition was poor.

  On the other hand, Comparative Example 2 has an oxygen content of 15 ppm, and in the subsequent annealing process during winding, there was no problem of the wires sticking to each other, but when welding the terminal and the oxygen-free copper rod, Bubbles are generated. Moreover, a thick oxide film was formed on the surface of the copper rod, and disconnection occurred during processing.

  As is apparent from Table 2, when producing an oxygen-free copper rod, the melt adhesion, cooling, hot rolling, recooling, and winding steps described in Example 1 were performed twice in Example 5 and Example. 6 was repeated 3 times and Example 7 was repeated 10 times. As a result, the oxygen-free copper rod obtained had an oxygen content of 2 to 5 ppm. When welding the terminal and the oxygen-free copper rod, there was no problem that bubbles were generated. Moreover, in the annealing process at the time of subsequent winding, the problem that the wires stick to each other did not occur, so the surface condition was very good. Furthermore, the problem of disconnection did not occur at all during processing.

  In the above invention, not only the temperature of the holding furnace 5 for keeping the molten copper and the temperature before entering the rolling treatment process by attaching the molten metal to the copper rod seed wire, but immediately after winding after processing. The temperature of the three processing steps including the temperature of was controlled. This made it possible to produce oxygen-free copper rods, which are high-quality copper wires with an oxygen content of 2 ppm to 10 ppm. In addition, by performing the above temperature control management, a special oxide film can be formed on the surface of the copper rod, and the wire rods in the copper rod can be prevented from sticking to each other in the subsequent annealing process during winding. In addition, since no flaws or disconnection occurred on the surface, it was possible to produce a high-quality oxygen-free copper rod with a good surface condition.

  According to the method for producing an oxygen-free copper rod according to the present invention, an oxygen-free copper rod having an arbitrary length, high conductivity, low oxygen content, and high tensile rate can be produced. It can be used in fields where high quality is required for copper rods, such as power generation, nuclear power generation, high-speed rail, in-vehicle conductors, and ultra-high-voltage wires.

DESCRIPTION OF SYMBOLS 1 Copper supply roller 2 Supply cart 3 Conveying roller 4 Melting furnace 5 Holding furnace 6 Adhering chamber 7 Wire drawing machine 8 Swaging machine 9 Pre-rolling tension controller 10 Series rolling machine 11 Post-rolling tension controller 12 Winding device 13 Finished product roller DESCRIPTION OF SYMBOLS 14 Emulsion cooling system 15 Seed line circulation supply device 16 Seed line connection machine 17 Waste wire winder 18 Peeling and straightening device 19 1st inductor 20 2nd inductor 21 3rd inductor 22 Runway 23 Holding furnace lid 24 Input port 25 Molten metal 26 Electrical copper plate 27 Exhaust port 28 Low level liquid level sensor 29 High level liquid level sensor 30 Ceramic partition wall 31 Copper rod

Claims (6)

After the copper material is heated in a drying furnace, it is poured into a melting furnace and melted, and the molten copper melt is poured into a holding furnace through a runner to keep it warm, and a single thin and continuous copper rod seed wire is formed. After passing through the adhesion chamber communicated with the holding furnace, adhere the molten metal to the surface of the copper rod seed wire, after obtaining a large-diameter copper rod, in order to cool the copper rod, hot rolling, A method for producing an oxygen-free copper rod that completes an oxygen-free copper rod by performing a recooling and winding process,
The temperature of the holding furnace for keeping the molten metal is 1140 ° C. to 1180 ° C., the temperature of the copper rod to which the molten metal is adhered is 600 ° C. to 800 ° C. before entering the hot rolling process after cooling, and the winding A method for producing an oxygen-free copper rod, wherein the temperature at the time of winding in the winding process is higher than room temperature and lower than 100 ° C. The temperature at the time of winding is 45 ° C. or more and 80 ° C. or less,
The manufacturing method of the oxygen-free copper rod of Claim 1. The temperature of the molten metal in the melting furnace is 1140 ° C to 1180 ° C,
The manufacturing method of the oxygen-free copper rod of Claim 1 or 2. The seed wire that is peeled before entering the adhesion chamber is a multilayer copper rod that has been subjected to the process of completing the oxygen-free copper rod at least twice,
The manufacturing method of the oxygen-free copper rod of Claim 1. The oxygen content of the oxygen-free copper rod after the winding step is 2 to 10 ppm,
The manufacturing method of the oxygen-free copper rod as described in any one of Claim 1 to 4. The oxygen-free copper rod is used as a copper wire material for in-vehicle electronic components,
The manufacturing method of the oxygen-free copper rod as described in any one of Claim 1 to 5.

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