JP4674483B2 - Copper material manufacturing method and copper material - Google Patents

Description

  The present invention relates to a method for producing a copper material, and more particularly to a copper material produced using a continuous casting and rolling apparatus.

  At present, most of various types of wires including copper wires are formed by a continuous casting and rolling method. First, the molten metal melted in the shaft furnace is supplied to the SCR type or Contirod (registered trademark) type continuous casting means to obtain a casting bar. Next, the casting bar is supplied to a hot rolling means connected to the continuous casting means and rolled to a predetermined outer diameter. Thereafter, the rolled material is cooled, and a rough drawing line is obtained.

  In the continuous casting and rolling method, each line of the melting step, the casting step, and the hot rolling step is continuous, which is an efficient method for producing the roughing wire and is an excellent method for productivity. The rough drawing wire thus obtained is then subjected to a cold drawing step and an annealing step to obtain a final product (for example, a copper wire).

JP-A-6-240426 JP 58-181853 A JP-A-2-104629

  By the way, industrial productivity can be improved by performing continuous annealing in the annealing process of copper wire manufacture (a cold wire drawing process and an annealing process are performed continuously). However, in this case, if the softening temperature of the annealed material is high, the annealing process takes time, and it is necessary to match the production speed of the cold drawing process with the production speed of the annealing process, which hinders the productivity of copper wire. Is done. Moreover, when the softening temperature of the material to be annealed is high, the thermal energy required for annealing increases, leading to an increase in manufacturing cost. Therefore, the softening temperature of the material to be annealed is lowered.

  In order to lower the softening temperature of the copper material, it is necessary to remove the impurity elements contained in the copper base material and increase the Cu purity. As a method for removing the impurity element, there are, for example, selection of a molten metal raw material (using a high-purity material), oxidation refining of the molten metal, reduction refining, and the like. However, this method of removing the impurity element is a method that is very expensive. For this reason, when tough pitch copper is used for the molten metal raw material, this method is extremely disadvantageous economically and cannot be said to be an industrially suitable method.

  On the other hand, as another method for lowering the softening temperature of the copper material, it is known that the concentration of a certain element among impurity elements contained in the copper base material may be lowered. One of the elements mentioned here includes sulfur (S) and lead (Pb) that are present in a solid solution state in Cu. In order to reduce the concentration of S and Pb solid-dissolved in Cu, measures such as vacuum degassing of the molten copper and heat treatment at a specific temperature on the copper bar after casting have been attempted. However, since these conventional measures cannot sufficiently reduce the concentration of S and Pb, the softening temperature of the copper material cannot be sufficiently lowered.

  An object of the present invention created in view of the above circumstances is to provide a copper material manufacturing method and a copper material that are inexpensive and have a low softening temperature.

In order to achieve the above object, a method for producing a copper material according to the present invention is a method for producing a copper material directly from a molten copper using a continuous casting and rolling device, and is stored in a molten metal storage means of the continuous casting and rolling device, At least one metal or alloy selected from Ti, Zr, V, Ta, Fe, Ca or Ni is added to a molten copper having an oxygen content of 0.02 to 0.05 % by mass, and the metal contained in the molten copper Alternatively, the ratio of the alloy is adjusted to 0.0007 to 0.05% by mass, a rough drawn material is produced using the molten copper, and the rough drawn material is subjected to cold drawing with a surface reduction rate of 30% or more. The wire drawing material is heat-treated at 100 to 600 ° C. for 1 hour or longer.

  On the other hand, the copper material according to the present invention is a copper material manufactured using the manufacturing method described above, and has a semi-softening temperature of 147 ° C. or lower.

  According to this invention, the outstanding effect that the copper material with a low softening temperature can be obtained is exhibited.

  Hereinafter, a preferred embodiment of the present invention will be described.

  The manufacturing method of the copper material which concerns on suitable one embodiment of this invention manufactures a copper material directly from molten copper using a continuous casting rolling apparatus.

Specifically, first, it is stored in a molten metal storage means (for example, tundish etc.) of a continuous casting and rolling apparatus, and an oxygen content of 0.05 mass % or less, for example, a tough pitch copper molten metal, Ti, Zr, V, At least one metal or alloy selected from Ta, Fe, Ca or Ni is added. At this time, the addition amount is adjusted so that the ratio of at least one metal contained in the molten copper is 0.0007 to 0.05 mass %. Any of these metals or alloys is a metal having a high affinity for S (hereinafter referred to as a sulfur affinity metal). The sulfur-affinity metal mentioned here may be either a simple substance or a mixture of metal elements, or a simple substance or a mixture of alloys.

  Next, the tough pitch copper molten metal containing a sulfur affinity metal is subjected to a casting process and a hot rolling process to continuously produce a roughing material (for example, roughing wire) of tough pitch copper. After that, the rough drawn material is subjected to cold drawing with a reduction in area of 30% or more and heat treatment at 100 to 600 ° C for 1 hour or more to obtain the final wire diameter. Copper with a semi-softening temperature of 147 ° C or less A material (for example, copper wire) is obtained. A product obtained by subjecting this copper material to annealing treatment is the final product. The semi-softening temperature referred to here is a temperature at which the tensile strength of the copper material after heating for 60 minutes becomes half the tensile strength of the copper material before heating.

The reason why tough pitch copper is used as the base material of the roughing material is that oxygen coexists in the copper base material at a ratio of 0.02% by mass to 0.05 % by mass (relatively exists). The oxygen reacts with various impurities dissolved in the copper base material to form oxides, thereby reducing the concentration of various impurities dissolved in the copper base material. The tough pitch copper is used because it is widely used as a copper wire material and is cheaper and more cost-effective than oxygen-free copper. Here, the tough pitch copper may be either one formed using only electric copper or one formed by mixing electric copper and scrap copper.

The content of sulfur affinity metal from 0.0007 to 0.05 wt%, preferably is was defined as 0.001 to 0.05 wt%, that's content is less than 0.0007 wt%, a solid solution of sulfur affinity metal and copper matrix This is because S which does not sufficiently react and the effect of lowering the softening temperature cannot be sufficiently obtained. On the other hand, when the content exceeds 0.05% by mass , the amount of the sulfur-affinity metal dissolved in the copper material is excessively increased, and the softening temperature of the copper material is increased.

  The reason for defining the area reduction rate of cold drawing as 30% or more is that if the area reduction rate is less than 30%, the effect of promoting the precipitation of S and Pb and reducing the softening temperature of the copper material is insufficient. It is because it becomes.

  The heat treatment temperature for the cold drawn wire was defined as 100 to 600 ° C. Here, the reaction for precipitating S, Pb and the like dissolved in the copper material is a diffusion reaction, and a sufficient reaction temperature (heating temperature) is required to sufficiently generate the diffusion reaction. When the heat treatment temperature is less than 100 ° C., the diffusion reaction cannot be sufficiently caused. In addition, when the heat treatment temperature exceeds 600 ° C., the solid solubility limit of S and Pb with respect to Cu increases, so the concentration of S and Pb that dissolve in the copper material increases conversely. As a result, the softening of the copper material The temperature rises further.

  On the other hand, the heat treatment time for the cold drawn wire was defined as 1 hour or more. Here, a sufficient reaction time (heating time) is required to sufficiently cause the diffusion reaction described above. When the heat treatment time is less than 1 hour, it is not possible to ensure a sufficient reaction time for precipitating S, Pb and the like dissolved in the copper material.

  The reason why the semi-softening temperature is defined as 147 ° C. or lower is that when the semi-softening temperature exceeds 147 ° C., the effect of reducing the softening temperature of the copper material is not sufficient.

  Here, the reason why the softening temperature of the copper material according to the present embodiment is greatly reduced is considered as follows.

Ordinary tough pitch copper contains about 10 ppm of S as a solid solution, and this S is said to be a major factor for increasing the softening temperature of the copper material. Therefore, in the manufacturing method according to the present embodiment, a sulfur-affinity metal is added at a predetermined ratio to a molten copper having an oxygen content immediately before casting of 0.05 mass % or less, for example, a tough pitch copper molten metal. The sulfur-affinity metal (for example, Ti) reacts with S that is dissolved in the tough pitch copper molten metal, so that S is precipitated as a sulfide (for example, TiS), and the solid solution amount of S is reduced. In addition, since the sulfur affinity metal becomes a nucleus when the tough pitch copper melt is solidified and recrystallized, the recrystallization generation energy of the tough pitch copper can be lowered.

Moreover, the rough-drawn material rapidly cooled through the hot rolling process of the continuous casting rolling method is in a state where impurity elements such as S and Pb are dissolved in a supersaturated state. However, in the manufacturing method according to the present embodiment, the rough drawn material that has been continuously cast and rolled is subjected to cold wire drawing with a reduction in area of 30% or more and heat treatment at 100 to 600 ° C. for 1 hour or more. In this way, by performing cold drawing on the roughing material, Cu atoms and S atoms can be easily diffused and moved by dislocations increased and grown during the cold drawing. As a result, during heat treatment, an impurity element such as S that is supersaturated in the copper material is combined with Cu and is likely to precipitate as a precipitate (for example, Cu ₂ S). In particular, S, which raises the softening temperature of copper, is easily precipitated by cold wire drawing and heat treatment since the solid solubility limit for Cu is small. As a result, it is considered that the concentration of S or Pb dissolved in the copper material is reduced, and the softening temperature of the copper material is lowered. Thus, it is considered that the softening temperature of the copper material can be greatly reduced by a combination of the effects of both (cold drawing and heat treatment).

  The form of the roughing material used in the manufacturing method according to the present embodiment and the finally obtained copper material is not particularly limited as long as it can be formed by surface reduction processing. For example, the shape is linear or plate-like. Or any of the stripes.

  Next, the operation of the copper material according to the present embodiment will be described.

  Usually, a copper material obtained by subjecting a rough drawing material to cold drawing, drawing and drawing is a wire material having high hardness (for example, hard copper wire) by work hardening. For this reason, when annealing normal copper wire, particularly when annealing annealing, high temperature and long time heat treatment is required.

However, the copper material obtained by the manufacturing method according to the present embodiment is a molten copper having an oxygen content of 0.05 % by mass or less, such as a tough pitch copper molten metal, from Ti, Zr, V, Ta, Fe, Ca, or Ni. At least one selected sulfur-affinity metal is added so that the content thereof is 0.0007 to 0.05% by mass .

  Here, since the sulfur affinity metal is a metal having a strong reactivity with oxygen, it easily reacts with oxygen in the atmosphere and oxidizes. Therefore, if it takes a long time to add the sulfur-affinity metal to the molten copper and actually use it for casting, it takes longer time for the sulfur-affinity metal to be exposed to the atmosphere. Additive loss. Therefore, it is important to suppress the reaction between the sulfur affinity metal and oxygen in the atmosphere. In the manufacturing method according to the present embodiment, a desirable timing for adding the sulfur affinity metal to the molten copper is immediately before casting. Moreover, the addition form of a sulfur affinity metal may add the simple substance of a sulfur affinity metal directly, However, It is preferable to add what was alloyed with the copper base material. Thereby, as described above, oxidation of the sulfur affinity metal can be suppressed. In addition, variation in the amount of addition can be suppressed, and as a result, the accuracy of the content of sulfur-affinity metal can be increased.

  The copper material obtained by the above manufacturing method uses tough pitch copper and has a softening temperature lower than that of a copper material manufactured by a conventional method (hereinafter referred to as a conventional copper material) (for example, semi-softening). The temperature becomes 147 ° C or less). For this reason, the copper material of the present embodiment can be sufficiently annealed at a lower temperature. Therefore, when performing annealing annealing, the copper material of the present embodiment can be annealed at a lower temperature and in a shorter time than a conventional copper material. As a result, productivity of the copper material is improved, and energy required for manufacturing the copper material can be reduced.

  The copper material of the present embodiment is made of inexpensive tough pitch copper and its softening temperature is significantly lower than that of the conventional copper material, so that the raw material cost and manufacturing cost of the final product are reduced, It is a copper material with very high industrial value.

  As described above, the present invention is not limited to the above-described embodiment, and it goes without saying that various other things are assumed.

  Next, although it demonstrates based on the Example of this invention, this invention is not limited to this Example.

Using a SCR-type continuous casting and rolling device connected to a shaft furnace, a rough drawn wire made of tough pitch copper and having a diameter of 8 mm was manufactured. The constituent material of the rough drawing wire is obtained by adding a sulfur-affinity metal to a tough pitch copper molten metal at a predetermined ratio. The rough drawing wire was repeatedly subjected to cold drawing and heat treatment as appropriate to produce copper wires having a diameter of 2.6 mm (Sample 1 to Sample 22 ).

Samples 1 to 4 are each in a state of rough drawing (no cold wire drawing and heat treatment),
A sulfur-affinity metal content of 0% by mass (Comparative Example 1)
A sulfur affinity metal content of 0.0003 mass % Ti (Comparative Example 2),
A sulfur affinity metal content of 0.003 mass % Ti (Comparative Example 3),
The one having a sulfur-affinity metal content of 0.06 mass % Ti was defined as (Comparative Example 4).

Samples 5 to 7 were obtained by subjecting a rough drawn wire having a sulfur-affinity metal content of 0.003 mass % Ti to cold drawing with a surface reduction rate of 30% and heat treatment at 400 ° C. for 60 minutes (Example) 1),
Cold drawn with a surface reduction of 20%, heat treated at 400 ° C for 60 min (Comparative Example 5),
Cold drawn with 50% area reduction, heat treated at 400 ° C x 60 min (Example 2),
It is.

Samples 8 to 10 were subjected to cold drawing with a surface reduction rate of 30% on the rough drawn wire having a sulfur-affinity metal content of 0.003 mass % Ti,
What was heat-treated at 100 ° C. for 60 minutes (Example 3),
Those subjected to heat treatment of 600 ° C. × 90 min (Example 4),
Heat-treated at 800 ° C for 30 min (Comparative Example 6)
It is.

Samples 11 and 12 are not subjected to cold wire drawing, each roughing feeder of sulfur affinity metal content of 0.003 wt% Ti, directly,
Heat-treated at 600 ° C x 30 min (Comparative Example 7)
Heat-treated at 800 ° C x 60 min (Comparative Example 8)
It is.

Samples 13 to 22 were obtained by subjecting a rough drawn wire containing a sulfur-affinity metal to cold drawing with a surface reduction rate of 30% and heat treatment at 400 ° C. for 60 minutes.
A sulfur-affinity metal content of 0% by mass (Comparative Example 9),
A sulfur affinity metal content of 0.0003 mass % Ti (Comparative Example 10),
A sulfur-affinity metal content of 0.06 mass % Ti (Comparative Example 11),
A sulfur-affinity metal content of 0.003 mass % Zr (Example 5),
A sulfur-affinity metal content of 0.003 mass % Fe (Example 6),
A sulfur-affinity metal content of 0.006 mass % Ta (Example 7 ),
The one having a sulfur affinity metal content of 0.0005 mass % Ni (Comparative Example 12),
A sulfur-affinity metal content of 0.01 mass % Ni (Example 8 ),
A sulfur-affinity metal content of 0.01 mass % Ni + 0.001 mass % Ti (Example 9 ),
A sample having a sulfur-affinity metal content of 0.01 mass % Ni + 0.001 mass % Mn was defined as (Example 10 ).

Softening tests were performed using the copper wires of Examples 1 to 10 and Comparative Examples 1 to 12, and the softening characteristics were evaluated. The results are shown in Table 1. Here, the evaluation of the softening characteristics was performed using the semi-softening temperature.

As shown in Table 1, each of the copper wires of Examples 1 to 10 has a sulfur-affinity metal content in the range of 0.0007 to 0.05% by mass , and satisfies the copper wire manufacturing method according to the present invention. It was. The semi-softening temperatures of the copper wires of Examples 1 to 10 are all 147 ° C. or lower (126 to 146 ° C.), and the semi-softening temperature (231 ° C.) of the copper wire to which no sulfur-affinity metal is added (Comparative Example 1). ), The semi-softening temperature was significantly reduced (over 80 ° C).

The copper wire of Comparative Example 2 has a sulfur-affinity metal content of 0.0003 mass % Ti, which is too small, so that no effect of lowering the softening temperature of the copper wire can be obtained. Was exactly 231 ° C. The copper wire of Comparative Example 4 has too much sulfur-affinity metal content of 0.06 mass % Ti, so the softening temperature of the copper wire is raised conversely, and the semi-softening temperature is copper with no sulfur-affinity metal added. The temperature was 100 ° C. (331 ° C.) higher than that of the wire (Comparative Example 1).

The copper wire of Comparative Example 3 has a sulfur-affinity metal content of 0.003 mass % Ti within the specified range, but is not subjected to cold wire drawing and heat treatment, so the semi-softening temperature (169 ° C) is sufficient. Could not be lowered.

The copper wire of Comparative Example 5 has a sulfur-affinity metal content of 0.003 mass % Ti and a heat treatment of 400 ° C. × 60 min, both within the specified range. Since it was as small as 20%, the semisoftening temperature (154 ° C.) could not be lowered sufficiently.

The copper wire of Comparative Example 6 has a sulfur-affinity metal content of 0.003 mass % Ti and a cold-drawing area reduction rate of 30%, both within the specified range, but the heat treatment temperature is 800 High as ℃. For this reason, compared with the copper wire of Example 1, the semi-softening temperature (172 ° C.) of the copper wire of Comparative Example 6 was significantly increased.

Each copper wire of Comparative Examples 7 and 8 has a sulfur-affinity metal content within the specified range of 0.003 mass % Ti, but is not subjected to cold drawing. For this reason, the copper wires of Comparative Examples 7 and 8 had higher semi-softening temperatures (148 ° C. and 163 ° C.) than the copper wires of Example 1, respectively.
In particular, when the copper wires of Comparative Examples 7 and 8 were compared, it was confirmed that the semi-softening temperature was increased by increasing the heat treatment temperature.

  Each of the copper wires of Comparative Examples 9 to 12 has a surface reduction rate of 30% in cold drawing and a heat treatment of 400 ° C. × 60 min, both within the specified range. Is outside the specified range. For this reason, compared with the copper wire of Example 1, the copper wires of Comparative Examples 9, 10, and 12 having a sulfur-affinity metal content that is less than the specified range have a semi-softening temperature (192 ° C., 192 ° C., 165 ℃) increased. Moreover, although the copper wire of the comparative example 11 with more content of a sulfur affinity metal than a regulation range has the semi-softening temperature low compared with the copper wire of the comparative example 4 by cold wire drawing and heat processing. It was still at a high level (292 ° C).

As described above, a sulfur-affinity metal is added to the tough pitch copper molten metal, which is a constituent material of the rough drawing wire, at a predetermined ratio, and the rough tough copper wire is supplied to the continuous casting rolling apparatus to produce the rough drawing wire. It was confirmed that the softening temperature of the copper wire can be greatly reduced by subjecting the drawn wire to cold drawing and heat treatment under predetermined conditions.

Claims (2)

In a method for producing a copper material directly from a molten copper using a continuous casting and rolling device,
At least one metal selected from Ti, Zr, V, Ta, Fe, Ca, or Ni is stored in the molten metal storage means of the continuous casting and rolling apparatus, and the molten copper having an oxygen content of 0.02 to 0.05 mass% , or Add an alloy , adjust the ratio of the metal or alloy contained in the molten copper to 0.0007-0.05 mass%, manufacture the roughing material using the molten copper, and reduce the surface reduction rate to the roughened material by 30% A method for producing a copper material, comprising performing the above cold wire drawing and heat-treating the cold wire at 100 to 600 ° C. for 1 hour or more.   A copper material manufactured using the manufacturing method according to claim 1, wherein a semi-softening temperature is 147 ° C. or lower.