JP5609564B2 - Manufacturing method of molten solder plating wire - Google Patents

Description

  The present invention relates to a method for manufacturing a molten solder-plated wire, and more particularly to a method for manufacturing a molten solder-plated wire that can omit the annealing step after processing the final wire diameter.

  In recent science and technology, electricity is used in all parts such as electric power as a power source and electric signals, and wires such as cables and lead wires are used to transmit them. And as a material used for the conducting wire, a metal having high conductivity such as copper and silver is used, and in particular, a copper wire is very often used in consideration of cost.

  The copper and lump can be broadly divided into hard copper and soft copper according to the molecular arrangement. And the kind of copper which has a desired property according to the utilization purpose is used.

  Hard lead wires are often used as lead wires for electronic parts. For example, cables used in electronic devices such as medical devices, industrial robots, and notebook computers are combined with severe bending, twisting, and tension. Since it is used in an environment where external force is repeatedly applied, rigid hard copper wire is inaccurate and soft copper wire is used.

  For example, Patent Document 1 discloses a round cross section used in a field where bending resistance is required, such as a portable information / communication / recording terminal such as an electronic device such as a notebook computer, a mobile phone, or a digital video camera. In the ultrafine copper alloy wire having a wire diameter of 0.01 to 0.1 mm, Mg or In is contained in an amount of 0.05 to 0.9% by mass, and copper and inevitable impurities are the balance. The copper alloy is drawn to form an ultrafine copper wire, and the ultrafine wire after final wire diameter formation is heat treated to have a tensile strength of 343 MPa or more, an elongation of 5% or more, and an electrical conductivity of 80% IACS. It is described that tempering as described above.

  Further, for example, Patent Document 2 discloses a Sn-based plated rectangular conductor having a conductor size of 0.035 mm in thickness and 0.30 mm in width for an Sn-based plated rectangular conductor used in a flexible flat cable for electronic equipment. After the production, a method for producing a flat conductor for a flexible flat cable that satisfies various specifications such as bending resistance by changing the annealing temperature condition in the final annealing of the flat conductor is described.

  Further, for example, in Patent Document 3, for a rectangular conductor used for an electrode wire for a solar cell, a Cu single layer is obtained by slitting a rolled sheet made of oxygen-free copper to obtain a core material at 500 ° C. It describes that a soft electrode wire for a solar cell is obtained by subjecting to × 1 minute softening annealing and plating.

  As described above, soft copper wires are used in a wide variety of technical fields. In the soft copper wire manufacturing method described in the above-mentioned patent document, the final wire diameter is determined in the manufacturing process of the soft copper wires. An annealing treatment is performed in another process in order to obtain soft characteristics. However, in the manufacturing process including the annealing process before the final wire diameter for the purpose of obtaining such soft characteristics, there are problems that productivity is inferior and manufacturing cost is increased.

  Thus, for example, Patent Document 4 relates to an electrode wire for solar cells. As a technique for easily producing a soft copper wire without providing a softening annealing step, the bath temperature of the molten solder bath is 250 ° C. or higher. 380 ° C. or lower, and the core material immersion time is 6 to 10 seconds when the bath temperature is 250 ° C. or higher and lower than 280 ° C., and 3 to 10 seconds when the bath temperature is 280 ° C. or higher and 350 ° C. or lower, or 350 It is described that it is 3 to 5 seconds when it is above 380 ° C. and below 380 ° C.

JP 2002-129262 A JP 2003-86024 A International Publication No. 2005/114751 Pamphlet International Publication No. 2007/037184 Pamphlet

  The manufacturing method described in Patent Document 4 is an effective technique in the sense that the annealing process can be omitted after finishing the final wire diameter processing, but in the product field that uses soft plated copper wires widely. In order to further reduce the manufacturing cost, an increase in the speed of the plating line is an important factor, and a further reduction in the plating immersion time of the copper wire is required.

  Moreover, the manufacturing method described in Patent Document 4 is used for a high-working element wire (in the example, a reduction rate of 95%) using an element wire made of oxygen-free copper. It is understood that the higher degree of workability is intended to soften the conductor by utilizing the phenomenon that the softening temperature in the heat treatment state becomes lower when immersed in the solder plating bath, and it is applied to the wire with higher workability However, for wire with a relatively low degree of processing, it has not yet been fully studied and applied to copper wire with a low degree of processing. In the process, there is a limit naturally, and a manufacturing technique that can be applied to a product type with a low degree of processing is required.

  Therefore, an object of the present invention is to make the immersion time in the solder plating bath shorter in producing a soft copper wire than in the case of using oxygen-free copper (OFC). An object of the present invention is to provide a method for producing a molten solder plating wire capable of realizing an increase in the speed of the plating line.

The present invention has been devised to achieve the above object, and the invention of claim 1 is characterized in that pure copper containing unavoidable impurities is added to 2 to 12 mass ppm of sulfur and more than 2 mass ppm of oxygen to 30 mass ppm or less . look containing a titanium 4～55Mass ppm, was added to the titanium to copper melt was melt at the molten copper temperature of 1200 ° C. or higher 1320 ° C. or less, after producing the ingot rod from molten copper in which the titanium is added, For the dilute copper alloy material manufactured through the process of hot rolling the ingot rod by controlling the temperature at the first rolling roll to 880 ° C. or lower and the temperature at the final rolling roll to 550 ° C. or higher . A step of producing a wire drawing material by drawing the final wire diameter, and a molten solder for forming a molten solder plating layer on the surface of the wire drawing material by immersing the wire drawing material in a molten solder plating bath A Kki step, in which the extension wire by heat of molten solder plating process was altered to a soft copper wire.

  In the invention of claim 2, the degree of processing when drawing to the final wire diameter is 50% or more, the plating temperature of the molten solder plating tank is 260 ° C to 300 ° C, and the immersion time is 2 to 5 It is a manufacturing method of the molten solder plating wire which is second.

In the invention of claim 3, the degree of processing when drawing to the final wire diameter is 50% or more, the plating temperature of the molten solder plating tank is over 300 ° C and 380 ° C or less , and the immersion time is 1 It is a manufacturing method of the molten solder plating wire which is less than second.

  In the invention of claim 4, the degree of processing when drawing to the final wire diameter is less than 50%, the plating temperature of the molten solder plating bath is 280 ° C to 380 ° C, and the immersion time is 1 to 10 It is a manufacturing method of the molten solder plating wire which is second.

  The invention of claim 5 includes a step of drawing a rough drawn wire made of a dilute copper alloy material before the step of drawing the final wire diameter, and subjecting the wire to electrical annealing after the drawing. It is a manufacturing method of a molten solder plating wire.

  Invention of Claim 6 is a manufacturing method of the molten solder plating wire provided with the rolling process process formed in flat shape by rolling this wire drawing material before the said molten solder plating process.

According to a seventh aspect of the present invention, in the diluted copper alloy material, the sulfur and the titanium form a compound or aggregate in the form of TiO, TiO ₂ , TiS, Ti—O—S, and the remaining titanium and the titanium This is a method for producing a molten solder plated wire which is a diluted copper alloy material in which sulfur is present in the form of a solid solution.

In the invention according to claim 8, the dilute copper alloy material is distributed in the crystal grains so that the TiO size is 200 nm or less, the TiO ₂ is 1000 nm or less, the TiS is 200 nm or less, and the Ti—O—S is 300 nm or less. And a method for producing a molten solder plated wire which is a dilute copper alloy material in which particles of 500 nm or less are 90% or more.

  According to the present invention, as compared with the case of using oxygen-free copper (OFC), in producing a soft copper wire, the immersion time in the solder plating bath can be performed in a shorter time, and a further plating line can be obtained. The speed can be increased.

It is a figure which shows the SEM image of a TiS particle | grain. It is a figure which shows the analysis result of FIG. Is a view showing an SEM image of the TiO ₂ particles. It is a figure which shows the analysis result of FIG. It is a figure which shows the SEM image of Ti-O-S particle | grains. It is a figure which shows the analysis result of FIG. It is a figure explaining the manufacturing method of the fusion | melting solder plating wire of this invention. It is a figure explaining the manufacturing method of the conventional fusion | melting solder plating wire.

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

First, the present invention uses an SCR continuous casting and rolling facility to reduce the softening temperature of a copper material that is a raw material of a molten solder plated wire, and has few surface scratches, a wide manufacturing range, and stable production. In addition, the development of a material having a softening temperature of 148 ° C. or less at a processing degree of 90% (for example, φ8 mm → φ2.6 mm) for the wire rod was examined. Moreover, although it is secondary, conductivity is 98% IACS (conductivity with universal standard soft copper (International Anne Copper Copper) resistivity 1.7241 × 10 ⁻⁸ Ωm being 100%), 100% IACS, An investigation was made to obtain conditions for producing a hot-dip soldered wire satisfying 102% IACS.

  For Cu (6N, purity 99.9999%), the softening temperature at a processing degree of 90% is 130 ° C. Therefore, the present invention provides a soft copper having a soft material having a softening temperature of 130 ° C. or higher and 148 ° C. or lower that allows stable production, and a conductivity of 98% IACS or higher, 100% IACS or higher, and a conductivity of 102% IACS or higher. We investigated to obtain the manufacturing conditions of the material as the molten solder plating wire that can be manufactured stably.

  Here, high purity copper (6N) having an oxygen concentration of 1 to 2 mass ppm was used, and a small continuous casting machine (small continuous casting machine) was used in a laboratory, and the molten metal was manufactured from a molten metal with several mass ppm added to the molten metal. When the softening temperature is measured with a φ8 mm wire rod φ2.6 mm (working degree 90%), it is 160 to 168 ° C., and the softening temperature is not lower than this. The conductivity is about 101.7% IACS. Therefore, it was found that even when Ti was added at a low oxygen concentration, the softening temperature could not be lowered, and the electrical conductivity of high purity copper (6N) was worse than 102.8% IACS.

  The reason for this is that sulfur is contained in several mass ppm or more as an unavoidable impurity during the production of molten metal, and sulphide such as TiS is not sufficiently formed between this sulfur and titanium, so that the softening temperature is not lowered. .

  Therefore, in the present invention, in order to lower the softening temperature and improve the electrical conductivity, the two measures have been studied and the two effects have been combined to achieve the goal.

(A) Increase the oxygen concentration of the material to an amount exceeding 2 mass ppm and add titanium. Thereby, it is considered that TiS, titanium oxide (TiO ₂ ) and Ti—O—S particles are first formed in the molten copper (see the SEM images in FIGS. 1 and 3 and the analysis results in FIGS. 2 and 4). ). In FIGS. 2, 4, and 6, Pt and Pd are vapor deposition elements for observation.

(B) Next, by setting the hot rolling temperature lower (880 to 550 ° C.) than the normal copper production conditions (950 to 600 ° C.), dislocations are introduced into the copper and S is likely to precipitate. Like that. As a result, precipitation of S on the dislocations or precipitation of S using titanium oxide (TiO ₂ ) as a nucleus forms Ti—O—S particles and the like as an example of molten copper (SEM image of FIG. 5 and FIG. 6 shows the analysis result).

  According to (a) and (b), sulfur in copper crystallizes and precipitates, and a copper wire rod that satisfies the softening temperature and conductivity after cold wire drawing can be obtained.

  Next, in this invention, (1)-(4) was restrict | limited as a restriction | limiting of manufacturing conditions with SCR continuous casting equipment.

(1) Restriction of composition When obtaining a soft copper material having an electrical conductivity of 98% IACS or higher, pure copper (base material) containing inevitable impurities is 3 to 12 mass ppm of sulfur, more than 2 and oxygen of 30 mass ppm or less. A wire rod (rough drawing wire) is manufactured from a dilute copper alloy material containing 4 to 55 mass ppm of Ti.
Also, other elements and impurities that do not adversely affect the properties of the alloy can be included in the alloy.

  Here, when obtaining a soft copper material having an electrical conductivity of 100% IACS or more, 2 to 12 mass ppm of sulfur, oxygen exceeding 2 to 30 mass ppm and Ti and Ti to 4 to 37 mass ppm are added to pure copper containing inevitable impurities. The wire rod is preferably made of a diluted copper alloy material.

  Furthermore, when obtaining a soft copper material having an electrical conductivity of 102% IACS or higher, pure copper containing inevitable impurities contains 3-12 mass ppm of sulfur, oxygen exceeding 2 and less than 30 mass ppm, and dilute containing 4-25 mass ppm of Ti. The wire rod is preferably made of a copper alloy material. In this embodiment, so-called low oxygen copper (LOC) is targeted because it contains oxygen exceeding 2 massppm and not more than 30 massppm.

  Usually, in the industrial production of pure copper, sulfur is taken into copper when producing electrolytic copper, so it is difficult to make sulfur 3 mass ppm or less. The upper limit of the sulfur concentration of general-purpose electrolytic copper is 12 mass ppm.

As described above, if the amount of oxygen to be controlled is small, the softening temperature is difficult to decrease, so the amount exceeds 2 mass ppm. Further, if there is too much oxygen, surface scratches are likely to occur in the hot rolling process, so it is set to 30 mass ppm or less. In addition, depending on the addition amount of the additive element and the content of S, it can exceed 2 mass ppm and contain 400 mass ppm within a range having the properties of the alloy.

(2) Restriction of dispersed substances It is desirable that the size of dispersed particles is small and distributed in large numbers. The reason is that it is required to have a small size and a large number because it functions as a sulfur precipitation site.

Sulfur and titanium form compounds or aggregates in the form of TiO, TiO ₂ , TiS, and Ti—O—S, and the remaining Ti and S are present in the form of a solid solution. A dilute copper alloy material in which the size of TiO is 200 nm or less, TiO ₂ is 1000 nm or less, TiS is 200 nm or less, and Ti—O—S is 300 nm or less is distributed in the crystal grains. “Crystal grains” means the crystal structure of copper.

  However, since the size of the formed particles changes depending on the holding time of the molten copper during casting and the cooling condition, it is necessary to set casting conditions.

(3) Restriction of casting conditions By SCR continuous casting and rolling, a wire rod is manufactured with an ingot rod working degree of 90% (30 mm) to 99.8% (5 mm). As an example, φ8 mm at a working degree of 99.3% There is a way to make a wire rod.

  (A) Molten copper temperature in a melting furnace shall be 1100 degreeC or more and 1320 degrees C or less. When the temperature of the molten copper is high, blowholes increase, scratches are generated, and the particle size tends to increase. The reason why the temperature is set to 1100 ° C. or higher is that copper is likely to solidify and the production is not stable, but the casting temperature is preferably as low as possible.

  (B) As for the hot rolling temperature, the temperature at the first rolling roll is 880 ° C. or lower, and the temperature at the final rolling roll is 550 ° C. or higher.

  Unlike normal pure copper production conditions, crystallization of sulfur in molten copper and precipitation of sulfur during hot rolling are the subject of the present invention, so in order to reduce the solid solubility limit that is the driving force. The molten copper temperature and the hot rolling temperature are preferably (a) and (b).

  The normal hot rolling temperature is such that the temperature at the first rolling roll is 950 ° C. or lower and the temperature at the final rolling roll is 600 ° C. or higher. In order to reduce the solid solution limit, The temperature at the first rolling roll is set to 880 ° C. or lower, and the temperature at the final rolling roll is set to 550 ° C. or higher.

The reason why the temperature is set to 550 ° C. or higher is that the wire rod has many scratches below this temperature, so that the product is not manufactured. The hot rolling temperature is preferably as low as possible, with the temperature at the first rolling roll being 880 ° C. or lower and the temperature at the final rolling roll being 550 ° C. or higher. By doing so, the softening temperature (after processing to φ8 mm to φ2.6 mm ) is infinitely close to Cu (6N, softening temperature 130 ° C.).

  (C) The electrical conductivity of a wire rod having a diameter of φ8 mm is 98% IACS or more, 100% IACS or more and 102% IACS or more, and the softening temperature of the wire rod (for example, φ2.6 mm) after cold drawing is 130 ° C. A dilute copper alloy wire or plate-like material having a temperature of ˜148 ° C. can be obtained.

  In order to use it industrially, it is necessary to use 98% IACS or more in the industrially used soft copper wire produced from electrolytic copper, and the softening temperature is 148 ° C. or less in view of its industrial value. When Ti is not added, the temperature is 160 to 165 ° C. Since the softening temperature of Cu (6N) was 127 to 130 ° C., the limit value is set to 130 ° C. from the obtained data. This slight difference is in inevitable impurities not found in Cu (6N).

  The conductivity is about 101.7% IACS at the level of oxygen-free copper, and 102.8% IACS at Cu (6N). Therefore, it is desirable that the conductivity be as close as possible to Cu (6N).

(4) Restriction of casting conditions The copper of the base material was controlled to be in a reduced state after melting in the shaft furnace, that is, the sulfur concentration of the constituent element of the dilute alloy in a reducing gas (CO) atmosphere, A method of stably producing a wire rod that is cast and rolled while controlling the Ti concentration and oxygen concentration is preferable. Since the copper oxide is mixed and the particle size is large, the quality is lowered.

  Here, the reason for selecting Ti as an additive is as follows.

  (A) Ti is easily bonded to sulfur in molten copper to form a compound.

  (B) It can be processed and handled more easily than other additive metals such as Zr.

  (C) It is less expensive than Nb or the like.

  (D) It is because it is easy to precipitate using an oxide as a nucleus.

  The dilute copper alloy material obtained by the above can be used as a soft copper wire because it can reduce the energy during molten solder plating material (wire, plate, foil), enameled wire, soft pure copper, high conductivity copper, and annealing. It is possible to obtain a practical dilute copper alloy material that is highly conductive and excellent in electrical conductivity, softening temperature, and surface quality.

  In the above-described embodiment, the wire rod is manufactured by the SCR continuous casting rolling method and the soft material is manufactured by hot rolling. However, the twin roll type continuous casting rolling method or the Properti type continuous casting rolling method has been described. You may make it manufacture by a method.

  Now, a method for producing a molten solder plated wire of the present invention using this diluted copper alloy material as a raw material will be described with reference to FIG.

  This plated wire is a copper wire having a plating layer on its surface. This copper wire is made of the above-mentioned diluted copper alloy material. Moreover, as a plating layer, what has tin, nickel, and silver as a main component is applicable, for example, you may use what is called Pb free plating.

  As shown in FIG. 7, the method of manufacturing a plated wire includes a wire drawing step of drawing the wire rod 2 made of the above-described diluted copper alloy material, and a flat conductor ( A rolling step for forming a soft flat conductor 10 and a solder plating step for forming a plating layer on the surface of the flat conductor 10. Here, although the case where a rolling process is included is demonstrated, the manufacturing method without this rolling process may be sufficient as the manufacturing method of the molten solder plating wire of this invention.

  The wire drawing apparatus 1 used in the wire drawing process draws the feed bobbin 3 around which the wire rod 2 made of the above-mentioned diluted copper alloy material is wound, and the wire rod 2 sent from the feed bobbin 3. It consists of a wire drawing machine 5 having a plurality of dies 4 and a winding bobbin 6 for winding the wire rod 2a after drawing. Further, when the wire rod is drawn, an electric heating device (not shown) is provided inside the wire drawing device 1, and the wire rod is sent out from the delivery bobbin 3, and the wire drawing material is taken up on the take-up bobbin 6. In particular, annealing treatment may be performed by a process such as energization annealing on the same line as the wire drawing. The object of the present invention is to omit the annealing step after finishing to the final wire diameter. Thus, in the stage before processing to the final wire diameter, on the same line as the wire drawing processing. In the case of performing the annealing process, since it is a short-time process, it is not a problem in terms of productivity, and the present invention is intended to exclude the case where such an annealing process is performed. is not.

  The rolling device 7 used in the rolling process is a rolling machine that rolls the wire bobbin 8 (winding bobbin 6) around which the wire rod 2 after drawing is wound and the wire rod 2a fed from the wire bobbin 8 from above and below. The rolling machine 11 has a roll 9 and processes the wire rod 2 a into a flat conductor 10, and a winding bobbin 12 that winds the flat conductor 10.

  A solder plating apparatus 13 used in the solder plating process is sent out from a delivery bobbin 14 (winding bobbin 12) around which a flat conductor 10 is wound, a solder plating tank 15 filled with a molten solder S, and a delivery bobbin 14. A plurality of pulleys 16 for guiding the flat conductor 10 to the solder plating tank 15 and a winding bobbin 18 for winding the flat conductor 17 having a plating layer formed on the surface of the flat conductor 10 through the solder plating tank 15.

  As shown in FIG. 8, conventionally, in order to produce a plated rectangular conductor 19, the round wire material 20 is made into a rectangular shape (flat conductor 21) in the processing step (the wire drawing step / rolling step), and finally the wire rod is finished. After performing an appropriate process, after the annealing process (heat treatment process), the manufacturing method in which it is immersed in the solder plating tank 15 and made into a plating composite material (flat conductor 19) is performed.

  However, the material 20 processed in the processing step had to be work-hardened and softened in the next annealing step. In the annealing process, the rectangular conductor 21 is annealed using the tubular furnace 22 or the batch furnace 23. For this reason, the manufacturing cost was high, and there were problems in economy and productivity.

  On the other hand, as described above, if the method for producing a molten solder plated wire according to the present invention is used, a material having a low semi-softening temperature is used, and therefore, a manufacturing process is performed from a processing process through an annealing process and a plating process. Thus, a product can be manufactured only from the processing step to the plating step without providing a softening annealing step after the final wire drawing process, so that the cost is low and high productivity is obtained.

  Furthermore, according to the present invention, based on the data shown in Tables 3 and 4 to be described later, compared to the case of using oxygen-free copper (OFC), in producing a soft copper wire, The dipping time can be performed in a shorter time, and further increase in the speed of the plating line can be realized.

  Table 1 relates to experimental conditions and results.

  First, as an experimental material, a φ8 mm copper wire (wire rod) with a processing degree of 99.3% was prepared with the oxygen concentration, sulfur concentration, and Ti concentration shown in Table 1. The φ8 mm copper wire is hot-rolled by SCR continuous casting and rolling. Ti flows the molten copper melted in the shaft furnace into the reed in the reducing gas atmosphere, guides the molten copper flowing in the reed to the casting pot of the same reducing gas atmosphere, and after adding Ti in this casting pot, An ingot rod was made with a mold formed between the cast ring and the endless belt through the nozzle. This ingot rod is hot-rolled to produce a φ8 mm copper wire. The experimental material was cold-drawn, the semi-softening temperature and conductivity at a size of φ2.6 mm were measured, and the dispersed particle size at a copper wire of φ8 mm was evaluated.

  The oxygen concentration was measured with an oxygen analyzer (Leco ™ oxygen analyzer). Each concentration of sulfur and Ti is the result of analysis with an ICP emission spectroscopic analyzer.

  The measurement of the semi-softening temperature in the size of φ2.6 mm was obtained from the result of quenching in water after holding each temperature at 400 ° C. or less for 1 hour and conducting a tensile test. Semi-softening the temperature corresponding to the strength showing half the difference in tensile strength, using the result of tensile test at room temperature and the result of tensile test of soft copper wire heat-treated at 400 ° C for 1 hour. Determined as temperature.

It is desirable that the dispersed particles have a small size and are distributed a lot. The reason is that the size is small and the number is large because it functions as a sulfur deposition site. That is, the case where the number of dispersed particles having a diameter of 500 nm or less was 90% or more was regarded as acceptable. Here, the “size” is the size of the compound and means the size of the major axis of the major axis and minor axis of the shape of the compound. “Particles” refer to TiO, TiO ₂ , TiS, and Ti—O—S. “90%” indicates the ratio of the number of corresponding particles to the total number of particles.

  In Table 1, the comparative material 1 is a result of trial production of a copper wire having a diameter of φ8 mm in an Ar atmosphere in a laboratory, and is obtained by adding 0 to 18 mass ppm of Ti to a molten copper.

  With this addition of Ti, 13 mass ppm decreases to 160 ° C. and becomes minimum with a semi-softening temperature of 215 ° C. where the Ti addition amount is zero, and increases with the addition of 15, 18 mass ppm, and the desired softening temperature is 148 ° C. or less. Did not become. However, although the industrially required conductivity was 98% IACS or more, it was satisfactory, but the overall evaluation was x.

  Therefore, a Ø8 mm copper wire (wire rod) was prototyped by adjusting the oxygen concentration to 7 to 8 mass ppm by the SCR continuous casting and rolling method.

  The comparative material 2 is one having a low Ti concentration (0.2 mass ppm) among the prototype manufactured by the SCR continuous casting and rolling method, and the conductivity is 102% IACS or more, but the semi-softening temperature is 164,157 ° C. Since the required temperature of 148 ° C. or lower was not satisfied, the overall evaluation was x.

  Regarding the implementation material 1, the oxygen concentration and the sulfur concentration are almost constant (7 to 8 mass ppm, 5 mass ppm), and the results of the prototype material having different Ti concentrations (4 to 55 mass ppm).

In this Ti concentration range of 4 to 55 mass ppm, the semi-softening temperature is 148 ° C. or less, the conductivity is 98% IACS or more, 102% IACS or more, and the dispersed particle size is also preferably 90% or more for particles of 500 nm or less. It is. And the surface of the wire rod is also clean, and all are satisfied as product performance (overall evaluation ○).

  Here, the case where the electrical conductivity satisfies 100% IACS or higher is when the Ti concentration is 4 to 37 mass ppm, and the case where the electrical conductivity satisfies 102% IACS or higher is when the Ti concentration is 4 to 25 mass ppm. When the Ti concentration was 13 mass ppm, the maximum conductivity was 102.4% IACS, and the conductivity was slightly lower in the vicinity of this concentration. This is because when Ti is 13 mass ppm, the sulfur content in copper is captured as a compound, thereby showing conductivity close to that of high-purity copper (6N).

  Therefore, both the semi-softening temperature and the conductivity can be satisfied by increasing the oxygen concentration and adding Ti.

  Comparative material 3 is a prototype material having a Ti concentration as high as 60 mass ppm. In this comparative material 3, the electrical conductivity satisfies the request, but the semi-softening temperature is 148 ° C. or higher, and the product performance is not satisfied. Furthermore, there were many surface damages on the wire rod, making it difficult to produce a product. Therefore, the addition amount of Ti is preferably less than 60 mass ppm.

  Next, Example Material 2 is a prototype material in which the sulfur concentration is set to 5 mass ppm, the Ti concentration is set to 13 to 10 mass ppm, and the oxygen concentration is changed to examine the influence of the oxygen concentration.

  Regarding the oxygen concentration, prototype materials with greatly different concentrations from 2 to 30 mass ppm or less were used. However, when oxygen is less than 2 mass ppm, production is difficult and stable production cannot be performed, so the overall evaluation is Δ. It was also found that even when the oxygen concentration was increased to 30 mass ppm, both the semi-softening temperature and the conductivity were satisfied.

  Moreover, as shown in the comparative material 4, when oxygen was 40 mass ppm, there were many scratches on the surface of the wire rod, and the product did not become a product.

  Therefore, by setting the oxygen concentration in the range of more than 2 and 30 mass ppm or less, the semi-softening temperature, the conductivity of 102% IACS or more, and the dispersed particle size can be satisfied, and the wire rod surface is also clean. Yes, both can satisfy product performance.

  Next, the embodiment material 3 is an example of a prototype material in which the oxygen concentration and the sulfur concentration are relatively close to each other, and the Ti concentration is changed to 4 to 20 mass ppm. In this material 3, the prototype material with less than 2 mass ppm of sulfur could not be realized from the raw material side, but by satisfying both the semi-softening temperature and the conductivity by controlling the concentrations of Ti and sulfur. Can do.

  When the sulfur concentration of the comparative material 5 was 18 mass ppm and the Ti concentration was 13 mass ppm, the semi-softening temperature was high at 162 ° C. and the required characteristics could not be satisfied. Moreover, since the surface quality of the wire rod was particularly poor, it was difficult to commercialize the product.

  From the above, when the sulfur concentration is 2 to 12 mass ppm, the characteristics of the semi-softening temperature, the conductivity of 102% IACS or more, and the dispersed particle size are all satisfied, and the surface of the wire rod is clean and all the product performance is achieved. I was satisfied.

  Moreover, although the examination result using Cu (6N) as the comparative material 6 was shown, the semi-softening temperature is 127 to 130 ° C., the conductivity is 102.8% IACS, and the dispersed particle size is 500 nm or less. It was not recognized at all.

  Table 2 shows the molten copper temperature and rolling temperature as the production conditions.

  Comparative material 7 shows the result of trial manufacture of a wire rod of φ8 mm at a molten metal temperature of 1330 to 1350 ° C. and a rolling temperature of 950 to 600 ° C.

  Although this comparative material 7 satisfied the semi-softening temperature and the electrical conductivity, the size of the dispersed particles was about 1000 nm, and the particles of 500 nm or more exceeded 10%. Therefore, this was inappropriate.

  The execution material 4 shows the result of trial manufacture of a φ8 mm wire rod at a molten copper temperature of 1200 to 1320 ° C. and a lower rolling temperature of 880 to 550 ° C. About this implementation material 4, the wire surface quality and the dispersed particle size were also good, and the overall evaluation was good.

  Comparative material 8 shows the result of trial production of a wire rod of φ8 mm at a molten copper temperature of 1100 ° C. and a lower rolling temperature of 880 to 550 ° C. Since this comparative material 8 had a low molten copper temperature, the wire rod had many surface scratches and was not suitable for the product. This is because scratches are likely to occur during rolling because the molten copper temperature is low.

  Comparative material 9 shows the result of trial production of a wire rod of φ8 mm at a molten copper temperature of 1300 ° C. and a higher rolling temperature of 950 to 600 ° C. Since this comparative material 9 had a high hot rolling temperature, the surface quality of the wire rod was good, but some of the dispersed particles were large, and the overall evaluation was x.

  Comparative material 10 shows the result of trial production of a wire rod of φ8 mm at a molten copper temperature of 1350 ° C. and a lower rolling temperature of 880 to 550 ° C. Since this comparative material 10 had a high molten copper temperature, some of the dispersed particles had a large size and the overall evaluation was x.

Table 3 shows immersion in a plating bath in the case of 92.1%, which is a relatively high degree of processing, with the conventional example using oxygen-free copper (OFC) as a sample and the example added with a small amount of Ti. It is the result of measuring the subsequent 0.2% yield strength value.
In order to grasp the softening characteristics of the sample after immersion, a 0.2% proof stress value was measured. The target value was set to 90 MPa or less. Here, as for the sample 5 for the execution material 5, after the third material from the top of the execution material 1 was drawn to φ2.6 mm, the annealing treatment was performed until the elongation was 30% on the same line. Furthermore, it was drawn to φ0.73 mm (working degree 92.1%). A molten solder plating step in the state of a hard copper wire without providing an annealing step to a flat wire having passed through a rolling process (0.2 × 2.0 mm) for forming the round wire into a flat shape. Then, a soft dilute copper wire having a molten solder plating layer around a flat wire was obtained by continuously dipping in a solder plating bath and pulling up with a pulling roll. On the other hand, the conventional material 1 was manufactured under the same conditions as the above-described embodiment material 5 except that oxygen-free copper (OFC) was used as a raw material. Here, the processing degree is expressed as “(cross-sectional area before processing−cross-sectional area after processing) / cross-sectional area before processing”.

As for sample Nos. 2 to 4 corresponding to the implementation material 5, when the solder plating temperature is 260 ° C. to 300 ° C., the immersion time is 2 to 5 seconds, and the 0.2% proof stress value is less than 90 MPa, and the immersion time It can be seen that a good soft copper wire is obtained in spite of being short. On the other hand, Sample Nos. 9 and 10, which are the conventional material 1, are examples in which the solder plating temperature is 260 ° C. and 280 ° C., although the immersion time is as long as 60 seconds, 0.2% The proof stress values exceeded the target value of 90 MPa. Similarly, Sample No. 11 which is the conventional material 1 has a 0.2% proof stress of 82 MPa, which is good, but the immersion time is long, resulting in poor productivity.
For sample Nos. 5 to 8, the hard copper wire was altered by the amount of heat in the molten solder plating process even though the solder plating temperature was 320 ° C. to 380 ° C. and the immersion time was 1 second. .2% proof stress value was less than 90 MPa, while sample Nos. 12 to 15 were all less than 0.2% proof stress value 90 MPa, but the immersion time was longer than Sample Nos. 5 to 8 Recognize.

  From the results of Table 3, when the material of the embodiment material 5 to which a small amount of Ti was added produced a soft copper wire compared to the conventional example using oxygen-free copper (OFC), the immersion time in the solder plating tank was further increased. It can be carried out in a short time, more specifically 260 to 300 ° C. for 2 to 5 seconds, and more than 300 ° C. to 380 ° C. or less to the target 0.2% proof stress value in 1 second or less. It can be said that it is more effective in terms of speeding up the plating line.

  For the comparative material 11, the 0.2% proof stress value was measured under the condition that the solder immersion time was 2 seconds when the solder plating temperature was 260 ° C., which was much higher than the target value of 90 MPa.

Table 4 shows the results of the conventional example using oxygen-free copper (OFC) as a sample and the example in which a small amount of Ti is added in the case of 47.7%, which is a relatively low degree of processing. It is the result of measuring a 0.2% yield strength value. The evaluation method for the 0.2% proof stress value is the same as in Table 3.
As for the sample, the material 6 is subjected to an annealing process until the third material from the top of the material 1 is drawn to φ2.6 mm and the elongation is 30% on the same line. Further, after this was drawn to φ1.01 mm, a current-carrying annealer was processed until the elongation became 30% on the same line. Subsequently, this was further drawn to φ0.73 mm to obtain a hard copper wire (working degree: 47.7%). The subsequent steps are the same as in Table 3. On the other hand, the conventional material 2 was manufactured under the same conditions as the above-described embodiment material 6 except that oxygen-free copper (OFC) was used as a raw material. The method for specifying the degree of processing is the same as that of the embodiment material 6 .

When the execution material 6 is seen, when the solder plating temperature is 280 ° C. to 380 ° C., the immersion time is 1 to 10 seconds and the 0.2% proof stress value is less than 90 MPa. It can also be seen that the hard copper wire is altered by the amount of heat in the molten solder plating process by immersion in the solder plating bath, and a good soft copper wire can be produced (Sample Nos. 18 to 23).
On the other hand, even when the conventional material 2 is seen, even if the immersion time is increased to 60 seconds at 260 ° C. to 320 ° C., the 0.2% proof stress exceeds 90 MPa, and the oxygen wire is used as the material for the copper wire. When copper (OFC) was used, it turned out that the softening effect of the copper wire by immersion to a solder plating tank is not acquired (sample No24-27). In addition, at 340 ° C. to 380 ° C., a 0.2% proof stress value is less than 90 MPa, but the immersion time in the solder plating tank is too long, 30 seconds and 60 seconds. (Sample Nos. 28 to 30). In addition, in the case where the immersion time was 30 seconds and 60 seconds at 340 ° C. to 380 ° C., the Cu of the wire rod was dissolved in the solder plating bath, the components of the plating bath were changed, and the solder of the subsequent wire rod was changed. Since it affects the composition quality of the plating layer, it cannot be applied to an actual plating production line.

  From the results shown in Table 4, the phenomenon that the wire material is softened due to the heat treatment effect by solder plating on the copper wire having a higher workability than the conventional material 2 (for example, the reduction ratio of 95% in Patent Document 4) is disclosed. However, in the present invention, the raw material of the copper wire itself is reviewed, and by adding a small amount of Ti to the copper material having a predetermined O content and S content from the approach of improving the composition component, relatively low processing is achieved. Even in such a region, it can be said that there is an advantage that the softening effect of the copper wire can be obtained by immersion in the solder plating tank without adversely affecting the quality of the solder plating layer.

  As for the comparative material 12, the 0.2% proof stress value was measured under the condition that the solder immersion time was 30 seconds and 60 seconds, respectively, when the solder plating temperature was 260 ° C., but it was a value near the target value of 90 MPa. However, it was necessary to make the solder immersion time longer than that of the working material 6, resulting in inferior productivity.

  In addition, as a result of soldering the sample of the implementation material 5 and the sample of the implementation material 6 to a solar battery cell (silicon substrate, thickness 200 μm) and examining the occurrence of cracks in the solar battery cell after soldering, In the examples, no cracks were observed. Therefore, when using the conductor of a present Example for a solar cell use, there exists an effect which can eliminate generation | occurrence | production of the crack of the photovoltaic cell resulting from the difference in the thermal expansion coefficient after soldering.

  In the embodiment of the present invention, a rectangular conductor has been described. However, the present invention is not particularly limited to this, and a wire having a round cross section may be used.

DESCRIPTION OF SYMBOLS 1 Wire drawing apparatus 2, 2a Wire rod 3, 8, 14 Sending bobbin 4 Dies 5 Wire drawing machine 6, 12 Winding bobbin 7 Rolling apparatus 9 Roll roll 10, 17, 19, 21 Flat conductor 13 Solder plating apparatus S Solder Molten metal 15 Solder plating tank 16 Pulley 20 Material 22 Tubular furnace 23 Batch furnace

Claims (8)

Pure copper containing unavoidable impurities, 2 to 12 mass ppm of sulfur, 2 mass ppm to more than 30 mass ppm of oxygen and 4 to 55 mass ppm of titanium, and a molten copper at a molten copper temperature of 1200 ° C. to 1320 ° C. After the titanium was added to the steel and the ingot rod was made from the molten copper to which the titanium was added, the temperature at the first rolling roll was controlled to 880 ° C. or lower, and the temperature at the final rolling roll was controlled to 550 ° C. or higher. A step of producing a wire drawing material by subjecting the diluted copper alloy material manufactured through a step of hot rolling to the ingot rod to wire drawing to a final wire diameter;
A molten solder plating step for forming a molten solder plating layer on the surface of the wire drawing material by immersing the wire drawing material in a molten solder plating tank, and transforming the wire drawing material into a soft copper wire by the amount of heat in the molten solder plating step A method for producing a molten solder-plated wire.   The degree of processing when drawing to the final wire diameter is 50% or more, the plating temperature of the molten solder plating bath is 260 ° C to 300 ° C, and the immersion time is 2 to 5 seconds. The manufacturing method of the molten solder plating wire of Claim 1 to do.   The degree of processing when drawing to the final wire diameter is 50% or more, the plating temperature of the molten solder plating tank is over 300 ° C and 380 ° C or less, and the immersion time is 1 second or less. The method for producing a molten solder-plated wire according to claim 1.   The degree of processing when drawing to the final wire diameter is less than 50%, the plating temperature of the molten solder plating bath is 280 ° C. to 380 ° C., and the immersion time is 1 to 10 seconds. The manufacturing method of the molten solder plating wire of Claim 1 to do. The method comprising the step of drawing a rough drawn wire made of a dilute copper alloy material before the step of drawing the final wire diameter, and subjecting the wire to electrical annealing after the drawing. The manufacturing method of the molten solder plating wire of any one of 1-4. The molten solder plated wire according to any one of claims 1 to 5 , further comprising a rolling step for forming the wire rod into a rectangular shape by rolling the wire drawing material before the molten solder plating step. Manufacturing method. In the diluted copper alloy material, the sulfur and the titanium form compounds or aggregates in the form of TiO, TiO ₂ , TiS, and Ti—O—S, and the remaining titanium and the sulfur exist in the form of a solid solution. method for producing a molten solder plated wire according to any one of claims 1 to 6, characterized in that a dilute copper alloy material in. In the diluted copper alloy material, the size of the TiO is 200 nm or less, the TiO ₂ is 1000 nm or less, the TiS is 200 nm or less, and the Ti—O—S is distributed in the crystal grains to 300 nm or less. The method for manufacturing a molten solder plated wire according to any one of claims 1 to 7 , wherein the method is a dilute copper alloy material of 90% or more.