JP2013039603A - Method of manufacturing molten solder-plated twisted wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a molten solder-plated twisted wire capable of performing immersion into a solder plating tank in a shorter time when manufacturing the soft copper twisted wire, and further increasing the speed of a plating line as compared with the case that oxygen-free copper (OFC) is used.SOLUTION: The method of manufacturing the molten solder-plated twisted wire includes: a wire drawing process A of applying a wire drawing process to a dilute copper alloy material containing copper containing inevitable impurities, oxygen of a quantity exceeding 2 mass ppm, and at least one kind of additive element out of Mg, Zr, Nb, Ca, V, N, Mn, Ti and Cr to manufacture a drawn wire 2a; a wire twisting process A of preparing a plurality of the drawn wires 2a to manufacture a twisted wire 9 by intertwisting them; and a molten solder plating process C of forming a plated layer on each surface of the drawn wires 2a by immersing the twisted wire 9 in a molten solder plating tank where each drawn wire 2a is transformed to a soft copper wire by the quantity of heat of the molten solder plating process C.

Description

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

  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, 0.05 to 0.9% by mass of Mg or In is contained, and copper and inevitable impurities are contained. The remaining copper alloy is drawn to form an ultrafine copper wire, and the ultrafine wire after final wire diameter formation is heat treated to give a tensile strength of 343 MPa or more, an elongation of 5% or more, and an electrical conductivity of 80%. It is described that tempering is more than IACS.

  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, increasing the speed of the plating line is an important factor, and further shortening of the plating immersion time of the copper wire and the copper twisted 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, the object of the present invention is to solve the above-mentioned problems, and in the production of soft copper stranded wire, the immersion time in the solder plating bath is shorter in comparison with the case of using oxygen-free copper (OFC). An object of the present invention is to provide a method for producing a molten solder-plated stranded wire that can be carried out and can further increase the speed of the plating line.

  The present invention was devised to achieve the above object, and the invention of claim 1 is directed to copper containing inevitable impurities, oxygen exceeding 2 mass ppm, Mg, Zr, Nb, Ca, V, , N, Mn, Ti, at least one additive element of Cr, a wire drawing process for producing a wire drawing material by drawing a dilute copper alloy material, and preparing a plurality of the wire drawing materials, A molten solder plating comprising a stranded wire process for producing a stranded wire by twisting them together and a molten solder plating step for forming a plating layer on the surface of the wire drawing material by immersing the stranded wire in a molten solder plating bath It is a method for producing a stranded wire, wherein the wire drawing material is transformed into a soft copper wire by the amount of heat in the process.

  Invention of Claim 2 is the titanium of 4 mass ppm or more and 55 mass ppm or less, and the said addition element contains sulfur of 2 mass ppm or more and 12 mass ppm or less, and oxygen exceeding 2 mass ppm and below 30 mass ppm. It is a manufacturing method of the described twisted wire.

  In the invention of claim 3, the degree of processing of the wire drawing material when it is drawn 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 The method for producing a molten solder-plated wire according to claim 1, wherein is 2 to 5 seconds.

  In the invention of claim 4, the degree of processing of the wire drawing material when drawn to the final wire diameter is 50% or more, the plating temperature of the molten solder plating tank exceeds 300 ° C, and is 380 ° C. 2. The method for producing a molten solder plated wire according to claim 1, wherein the time is 1 second or more.

  In the invention of claim 5, 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 2. The method for producing a molten solder plated wire according to claim 1, wherein the second is a second.

  As compared with the case of using oxygen-free copper (OFC), the present invention can perform a dipping time in a solder plating tank in a shorter time in producing a solder-plated soft copper stranded wire, and further plating. It exhibits an excellent effect that the speed of the line can be increased.

It is a figure explaining the manufacturing method of the molten solder plating twisted wire of this invention. It is a figure explaining the manufacturing method of the conventional molten solder plating twisted wire.

  A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the manufacturing method of the molten solder plated stranded wire of the present invention is selected from the group consisting of Ti, Mg, Zr, Nb, Ca, V, Ni, Mn, and Cr in the wire drawing step A. The wire rod 2 made of a soft dilute copper alloy material containing the added elements and the balance being copper and inevitable impurities is drawn to the final wire diameter to obtain a wire drawing material 2a. A plurality of wiredrawing materials 2a are twisted to form a stranded wire 9, and in the plating step C, the stranded wire 9 is subjected to molten solder plating through the solder plating tank 13 and the stranded wire 9 is annealed at the temperature of the plating bath. It is a thing.

  The wire drawing apparatus 1 in the wire drawing process A draws the wire rod 2 from the delivery bobbin 3 through a wire drawing machine 5 provided with a plurality of dies 4 so that the degree of processing becomes 50% or more. The wire diameter is taken up and the drawn wire 2a is wound around the winding bobbin 6.

  The stranded wire device 7 in the stranded wire process B is a device in which a wire drawing material 2a having a final wire diameter is sent out from a plurality of delivery bobbins 8 and twisted to be wound around a take-up bobbin 10 as a stranded wire 9. .

  The plating apparatus 11 in the plating step C performs hot-dip solder plating on the stranded wire 9 by immersing the stranded wire 9 from the delivery bobbin 12 into the molten solder 14 in the solder plating tank 15 with a plurality of guide rolls 13. Then, it is wound around the winding bobbin 17 as a molten solder plating stranded wire 16. At this time, the plating temperature of the solder plating tank 15 is 260 ° C. to 300 ° C., the immersion time of the stranded wire 9 is 2 to 5 seconds, or the temperature exceeds 300 ° C. and 380 ° C., and the immersion time is 1 second or more. Thus, the stranded wire 19 can be plated and annealed simultaneously in the plating bath.

  Next, the structure of the conductor used for the stranded wire which concerns on this Embodiment is demonstrated.

(1) About additive element The conductor used for the twisted wire which concerns on this Embodiment contains the additive element selected from the group which consists of Ti, Mg, Zr, Nb, Ca, V, Ni, Mn, and Cr, A soft dilute copper alloy material with the balance being copper and inevitable impurities.

  The reason for selecting an element selected from the group consisting of Ti, Mg, Zr, Nb, Ca, V, Ni, Mn, and Cr as an additive element is that these elements are easily active elements that are easily combined with other elements. This is because S can be trapped because it is easily combined with S, and the copper base material (matrix) can be highly purified and the hardness of the material can be reduced. One or more additive elements may be included. Also, other elements and impurities that do not adversely affect the properties of the alloy can be included in the alloy.

  Further, in the preferred embodiment described below, it is explained that the oxygen content is better than 2 mass ppm and 30 mass ppm or less, but depending on the addition amount of the additive element and the S content, In the range having the properties of an alloy, it can contain more than 2 and 400 mass ppm.

(2) About composition ratio Since the conductor used for the twisted wire which concerns on this Embodiment is used as an electroconductive material, the thing with higher electroconductivity is preferable.

For example, the stranded wire according to the present embodiment has a conductivity of 98% IACS (conductivity when the universal annealed copper standard or higher, resistivity 1.7241 × 10 ⁻⁸ Ωm is 100%), It is preferable that a soft dilute copper alloy material as a soft copper material satisfying 100% IACS or more, more preferably 102% IACS or more is used.

  When obtaining a soft copper material with a conductivity of 98% IACS or higher, as pure copper (base material) containing inevitable impurities, sulfur of 3 mass ppm to 12 mass ppm, oxygen of more than 2 mass ppm and oxygen of 30 mass ppm or less, and 4 mass ppm A soft dilute copper alloy material containing 55 mass ppm or less of titanium is used, and a wire rod (rough drawing wire) is manufactured from the soft dilute copper alloy material.

  Here, when obtaining a soft copper material having an electrical conductivity of 100% IACS or more, as pure copper (base material) containing inevitable impurities, sulfur of 2 mass ppm to 12 mass ppm, and more than 2 mass ppm and 30 mass ppm or less. A soft dilute copper alloy material containing oxygen and titanium of 4 mass ppm to 37 mass ppm is used.

  Further, when obtaining a soft copper material having an electrical conductivity of 102% IACS or more, as pure copper (base material) containing inevitable impurities, sulfur of 3 mass ppm to 12 mass ppm and oxygen of more than 2 mass ppm and 30 mass ppm or less. And a soft dilute copper alloy material containing 4 mass ppm or more and 25 mass ppm or less of titanium.

  Usually, in the industrial production of pure copper, sulfur is taken into copper when producing electrolytic copper. Therefore, it is difficult to reduce sulfur to 3 mass ppm or less. The upper limit of the sulfur concentration of general-purpose electrolytic copper is 12 mass ppm. In this embodiment, so-called low oxygen copper (LOC) is targeted because it contains oxygen exceeding 2 mass ppm and not more than 30 mass ppm.

  When the oxygen concentration is low, the hardness of the conductor used for the stranded wire is difficult to decrease, so the oxygen concentration is controlled to an amount exceeding 2 mass ppm. Further, when the oxygen concentration is high, the surface of the conductor is likely to be damaged in the hot rolling process, so it is controlled to 30 mass ppm or less.

(3) About dispersed substances It is preferable that the size of the dispersed particles dispersed in the conductor used in the stranded wire according to the present embodiment is small, and a large number of dispersed particles are dispersed in the conductor. It is preferable. The reason for this is that the dispersed particles have a function as a sulfur precipitation site, and the precipitation sites are required to have a small size and a large number. As a result, the formation of the dispersed particles and the deposition of sulfur on the dispersed particles are required. This is because the purity of the matrix of the copper base material is improved and the material hardness is reduced.

Specifically, sulfur and titanium contained in the conductor are TiO, TiO ₂ , TiS, or a compound having a Ti—O—S bond or a compound having a TiO, TiO ₂ , TiS, or Ti—O—S bond. It is contained as an aggregate and the remaining Ti and S are contained as a solid solution.

(Manufacturing method of conductor used for stranded wire according to this embodiment)
The manufacturing method of the conductor used for the twisted wire which concerns on this Embodiment is as follows. As an example, a case where Ti is selected as an additive element will be described.

  First, a soft diluted copper alloy material containing Ti as a raw material for stranded wire is prepared (raw material preparation step).

  Next, this soft dilute copper alloy material is made into a molten metal at a molten copper temperature of 1100 ° C. or higher and 1320 ° C. or lower (melt manufacturing process).

  Next, a wire rod is produced from the molten metal (wire rod production process).

  Subsequently, the wire rod is hot-rolled at a temperature of 880 ° C. or lower and 550 ° C. or higher (hot rolling step).

  Further, the wire rod that has undergone the hot rolling process is subjected to wire drawing and heat treatment (wire drawing, heat treatment step).

  As a heat treatment method, traveling annealing using a tubular furnace, electric annealing using resistance heat generation, or the like can be applied. In addition, batch-type annealing is also possible.

  Thereby, the conductor used for the twisted wire which concerns on this Embodiment is manufactured.

  In addition, the conductor is manufactured using the soft dilute copper alloy material containing the above-described sulfur of 2 mass ppm to 12 mass ppm, oxygen of 2 mass ppm to 30 mass ppm, and titanium of 4 mass ppm to 55 mass ppm. Is preferred.

  Therefore, the present inventor has studied the following two measures in order to realize a decrease in the hardness of the conductor used in the stranded wire according to the present embodiment and an improvement in the conductivity of the conductor. And the conductor used for the twisted wire which concerns on this Embodiment was obtained by using together the following two measures for manufacture of a copper wire rod.

First, the first strategy is to prepare a molten Cu in a state where titanium (Ti) is added to Cu having an oxygen concentration exceeding 2 mass ppm. It is considered that TiS and titanium oxide (for example, TiO ₂ ) and Ti—O—S particles are formed in the molten metal.

Next, the second policy aims to facilitate the precipitation of sulfur (S) by introducing dislocations in the copper, and the temperature in the hot rolling process is set to the temperature in the normal copper production conditions (that is, , 950 ° C. to 600 ° C.) lower temperature (880 ° C. to 550 ° C.). With such a temperature setting, S can be precipitated on dislocations or by using titanium oxide (for example, TiO ₂ ) as a nucleus.

  By the first and second measures described above, sulfur contained in copper crystallizes and precipitates, so that a copper wire rod having desired soft characteristics and desired conductivity is obtained after cold drawing. be able to.

  The conductor used for the stranded wire according to the present embodiment uses SCR continuous casting equipment, has few scratches on the surface, has a wide manufacturing range, and can be stably produced.

  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, a condition for manufacturing a wire rod of φ8 mm with a processing degree of 99.3% is adopted.

  The molten copper temperature in the melting furnace is preferably controlled to 1100 ° C. or higher and 1320 ° C. or lower. When the temperature of the molten copper is high, blowholes increase, and scratches are generated and the particle size tends to increase, so the temperature is controlled to 1320 ° C. or lower. Moreover, although the reason for controlling to 1100 degreeC or more is because copper is hardened easily and manufacture is not stable, molten copper temperature is desirable as low as possible.

  As for the temperature of the hot rolling process, it is preferable to control the temperature in the first rolling roll to 880 ° C. or lower and the temperature in the final rolling roll to 550 ° C. or higher.

  These casting conditions are different from normal pure copper production conditions, and aim to further reduce the solid solubility limit, which is the driving force for sulfur crystallization in molten copper and precipitation of sulfur during hot rolling. Is.

  Further, the temperature in the normal hot rolling process is 950 ° C. or less in the first rolling roll and 600 ° C. or more in the final rolling roll, but for the purpose of reducing the solid solution limit, It is desirable to set 880 ° C. or lower for the first rolling roll and 550 ° C. or higher for the final rolling roll.

  The reason why the temperature in the final rolling roll is set to 550 ° C. or higher is that when the temperature is lower than 550 ° C., the obtained wire rod has many scratches and the manufactured conductor cannot be handled as a product. The temperature in the hot rolling process is preferably as low as possible while controlling the temperature to 880 ° C. or lower in the first rolling roll and 550 ° C. or higher in the final rolling roll. By setting such a temperature, the hardness of the conductor matrix can be made close to that of high-purity copper (5N or more).

  After the base material copper is melted in the shaft furnace, it is preferably flowed into the trough in a reduced state. That is, in a reducing gas (for example, CO) atmosphere, the wire rod is stably manufactured by casting while controlling the sulfur concentration, titanium concentration, and oxygen concentration of the dilute alloy and rolling the material. It is preferable. In addition, mixing of copper oxide and / or a particle size larger than a predetermined size degrades the quality of the manufactured conductor.

  From the above, a soft dilute copper alloy material that is softer than the oxygen-free copper (OFC) conductor can be obtained as a raw material for the conductor used in the stranded wire according to the present embodiment.

  A plating layer can also be formed on the surface of the soft dilute copper alloy material. Furthermore, the shape of the soft dilute copper alloy material is not particularly limited, and can be a round cross-section, a rod, or a flat conductor.

  In the present embodiment, the wire rod is manufactured by the SCR continuous casting and rolling method, and the soft material is manufactured by hot rolling, but the twin roll type continuous casting rolling method or the Properti type continuous casting and rolling method is adopted. You can also.

  Now, the manufacturing method of the molten solder plating stranded wire of this invention which used this diluted copper alloy material as a raw material is demonstrated again using FIG.

  This plated stranded wire is a molten solder plated stranded wire 16 having a plating layer on its surface. The molten solder plated stranded wire 16 is made of the above-described 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.

  The manufacturing method of the molten solder plated stranded wire 16 includes a wire drawing step A for drawing the wire rod 2 made of the above-mentioned diluted copper alloy material, and a wire drawing material 2a made of a hard copper wire drawn to the final wire diameter. Are provided with a stranded wire process B for twisting and a solder plating process C for forming a plating layer on the surface of the stranded wire 9.

  FIG. 2 shows a manufacturing method for manufacturing a conventional molten solder-plated stranded wire 25.

  The process of manufacturing the conventional molten solder-plated stranded wire 25 includes a plating process D, a wire drawing / annealing process E, and a stranded wire process F. The plating apparatus 11 in the plating process D, the wire drawing / annealing process E The wire drawing device 1 and the wire drawing device 7 in the stranded wire process F are basically the same as the plating device 11, the wire drawing device 1 and the wire drawing device 7 described in FIG. I will explain.

  The conventional molten solder-plated stranded wire 25 shown in FIG. 2 is manufactured by plating the rod (copper element wire) 2 with the plating device 11 before the final wire diameter to form a plated wire 18. The apparatus 1 is drawn to the final wire diameter to obtain a wire drawing material 19, and is energized between the guide rollers 21, 22 while being wound around the take-up bobbin 24 through the guide rollers 20, 21, 22. Line 23. Thereafter, the flexible copper wire 23 is twisted together with the twisted wire device 7 to form the twisted wire 25.

  However, the plated stranded wire 25 twisted together in the stranded wire process F is work-hardened in the stranded wire process F, and although it is a soft stranded wire, there is a problem that it does not become a complete soft stranded wire.

  On the other hand, as described above, if the method for producing a molten solder-plated twisted wire of the present invention is used, a material having a low semi-softening temperature is used. A product can be manufactured only by a twisting process and a plating process from a processing process, energy can be reduced at a low cost, and high productivity can be obtained.

  Furthermore, according to the present invention, based on the data shown in Table 1 and Table 2 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 shows oxygen-free copper (OFC) sample No. Sample No. 9 was prepared by adding a small amount of Ti to conventional material A 9 to 15 and oxygen-free copper. The result of having measured the Vickers hardness when changing the solder plating temperature and immersion time to the comparative material A and the implementation material A which were set to 1-8 is shown.

  These sample Nos. 1 to 15 are the results of measuring the Vickers hardness after immersion in the plating tank in the case of 91.7%, which is a relatively high workability.

  In order to grasp the softening characteristics of the sample after immersion, Vickers hardness was measured. The target value was set to 60 HV or less.

  The reason why the Vickers hardness is specified to be 60 or less is that when the Vickers hardness exceeds this value, the soft characteristics of the cable are insufficient, and there is a possibility that inconvenience may occur during cable routing.

  Here, Sample No. For the material A of 2 to 8, the material obtained by adding 13 mass ppm of Ti to low oxygen copper (oxygen concentration of 7 to 8 mass ppm, sulfur concentration of 5 mass ppm) was drawn to φ0.9 mm and then stretched on the same line. The energization annealer is processed until it reaches 30%, and is further drawn to φ0.26 mm (working degree: 91.7%). Thereafter, for example, seven stranded wires are used. Without providing an annealing step, this stranded wire is continuously immersed in a solder plating bath in the state of a hard copper stranded wire and pulled up by a pulling roll to form a molten solder plating layer around the wire. The obtained soft copper stranded wire is obtained.

  On the other hand, the conventional material A was manufactured under the same conditions as the above-described material A 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”.

  Sample No. corresponding to the execution material A 2 to 4, when the solder plating temperature is 260 ° C. to 300 ° C., the immersion time is 2 to 10 seconds, the Vickers hardness is less than 60 HV, and the solder is good despite the short immersion time. It can be seen that a plated soft copper stranded wire is obtained.

  On the other hand, Sample Nos. 9 and 10 which are the conventional material A are examples in which the solder plating temperature is 260 ° C. and 280 ° C., but the immersion time is 60 seconds and the Vickers hardness is Both exceeded the target value of 60HV.

  Moreover, about sample Nos. 5-8 corresponding to the implementation material A, the hard copper twisting is performed depending on the amount of heat in the molten solder plating process even though the solder plating temperature is 320 ° C. to 380 ° C. and the immersion time is 1 second. The lines were altered, and the Vickers hardness was below 60 HV, whereas the samples No. 12 to 15 as the conventional material A did not fall below the Vickers hardness of 60 HV, and sample Nos. 5 to 8 corresponding to the implementation material A It can be seen that it is harder than

  From these results in Table 1, when the material of the implementation material A to which a small amount of Ti was added produced a soft copper stranded wire with respect to the conventional example using oxygen-free copper (OFC), the immersion time in the solder plating tank was It can be performed in a shorter time. More specifically, the target Vickers hardness is reached in 1 second or less if it is 260 ° C to 300 ° C and 2 to 10 seconds if it exceeds 320 ° C and 380 ° C or less. It can be said that it is more effective in terms of speeding up the plating line.

  As for Comparative Material A, the Vickers hardness was measured under the condition that the solder immersion time was 10 seconds when the solder plating temperature was 260 ° C., which was much higher than the target value of 60 HV.

  Table 2 shows that in the case of 49.3%, which is a relatively low degree of processing, oxygen-free copper (OFC) is sample No. Conventional material B having 24 to 30 and sample No. 2 in which a slight amount of Ti is added to oxygen-free copper. Nos. 16 and 17 and Sample No. It is the result of having measured the Vickers hardness after plating tank immersion for the implementation material B of 18-23. The evaluation method of Vickers hardness is the same as in Table 1.

  Here, sample No. For Example Material B of 18 to 23, after the material was drawn to φ0.9 mm, it was subjected to energization annealing until the elongation reached 30% on the same line, and further drawn to φ0.365 mm. The energization annealing was performed until the elongation reached 30% on the same line. Subsequently, this was further drawn to φ0.26 mm, and then, for example, 7 stranded wires were obtained to obtain a hard copper stranded wire (working degree: 49.3%). The subsequent steps are the same as those in Table 1. In addition, the raw material of the implementation material B was the same as that of the implementation material A.

  On the other hand, the conventional material B was manufactured under the same conditions as the above-mentioned material B except that oxygen-free copper (OFC) was used as a raw material. In addition, about the specific method of a work degree, it is the same as that of the implementation material A.

  As for the execution material B, when the solder plating temperature is 280 ° C. to 380 ° C., the immersion time is 1 to 10 seconds and the Vickers hardness is less than 60 HV. It can be seen that the hard copper stranded wire is denatured by the amount of heat in the molten solder plating process by immersion in the bath, and a good solder-plated soft copper stranded wire can be produced (Sample Nos. 18 to 23).

  On the other hand, even in the case of the conventional material B, even if the immersion time was increased to 60 seconds at 260 ° C. to 320 ° C., the Vickers hardness exceeded 60 HV, and oxygen-free copper (OFC) was used as the copper wire material. ) Was used, it was found that a copper wire softening effect by immersion in a solder plating bath could not be obtained (Sample Nos. 24-27). Further, even at 340 ° C. to 380 ° C., the Vickers hardness exceeded 60 HV. Moreover, since immersion time in the solder plating tank was too long as 30 seconds, it turned out that it is inferior in terms of productivity (sample No. 28-30). 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 2, the phenomenon that the wire material is softened due to the heat treatment effect by solder plating is disclosed for the copper wire having a higher workability than the conventional material B (for example, 95% reduction in Patent Document 4). 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.

  In addition, for the comparative material A, when the solder plating temperature was 260 ° C., the Vickers hardness was measured under the condition that the solder immersion time was 30 seconds and 60 seconds, respectively, but the result was below the target value of 60 HV. It was necessary to make the solder immersion time longer than that of the implementation material B, resulting in inferior productivity.

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

DESCRIPTION OF SYMBOLS 1 Wire drawing apparatus 2 Wire rod 2a Wire drawing material 7 Twisted wire apparatus 9 Twisted wire 11 Solder plating apparatus 16 Molten solder plating twisted wire

Claims (5)

For a dilute copper alloy material containing copper containing inevitable impurities, oxygen in an amount exceeding 2 mass ppm, and at least one additive element of Mg, Zr, Nb, Ca, V, N, Mn, Ti, and Cr A wire drawing process for producing a wire drawing material by performing wire drawing;
Preparing a plurality of the wire drawing materials, and twisting them to produce a stranded wire; and
A molten solder plating step of forming a plating layer on the surface of the wire drawing material by immersing the stranded wire in a molten solder plating tank;
A method for producing a stranded wire, wherein a wire drawing material is transformed into a soft copper wire by the amount of heat in a molten solder plating process.   2. The method for producing a stranded wire according to claim 1, wherein the additive element is titanium of 4 mass ppm or more and 55 mass ppm or less, and includes sulfur of 2 mass ppm or more and 12 mass ppm or less and oxygen of more than 2 mass ppm and 30 mass ppm or less. .   The degree of processing of the wire drawing material when drawn 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 seconds. The method for producing a molten solder plated wire according to claim 1.   The degree of processing of the wire drawing material when drawn 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., and the immersion time is 1 second or more. The method for producing a molten solder plated wire according to claim 1.   The degree of processing of the wire drawing material when drawn to the final wire diameter is less than 50%, the plating temperature of the molten solder plating tank is 280 ° C. to 380 ° C., and the immersion time is 1 to 10 seconds. The method for producing a molten solder plated wire according to claim 1.

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