KR102465440B1 - Wire rod having high strength and high conductivity, and method for manufacturing thereof - Google Patents

Abstract

The present invention relates to a high-strength, high-conductivity iron-copper wire and a method for manufacturing the same. A process of injecting into a mold and manufacturing an ingot, a process of rolling the ingot at a rolling ratio of 40 to 60%, and drawing the rolled ingot at a reduction in area of 10 to 20%, and annealing between the drawing steps It characterized in that it comprises a process of thinning by performing the process.

Description

High-strength, high-conductivity iron-copper wire and manufacturing method thereof

The present invention relates to a high-strength, high-conductivity iron-copper wire and a method for manufacturing the same, and more particularly, it can be used for the production of materials for electronic components, the production of various iron-copper alloy materials, and furthermore, the alloy production technology of copper alloys.

Due to the recent trend of high integration of information and communication products and weight reduction of automobiles, electronic components used are gradually becoming smaller and highly integrated. There is a demand for a better material that can be adapted to the

In particular, high integration is essential to solve the heat dissipation problem. In relation to this problem, related materials must, firstly, have excellent electrical conductivity in order to reduce the generation of heat, and secondly, in order to dissipate the generated heat well. Thermal conductivity must be excellent, and thirdly, heat resistance, that is, hot strength, must be excellent in order not to be easily deformed even when the temperature of the material rises.

In general, since electrical conductivity and thermal conductivity of metal materials have the same tendency, copper alloys have been mainly used from this point of view. Since pure copper has low strength, in order to compensate for this, a second or third element is alloyed to increase the strength. raised and used. In this case, if other elements are added to copper, the electrical and thermal conductivity is lowered. The alloy design has been designed to minimize the decrease in conductivity.

Currently, various copper alloys such as phosphor copper, beryllium copper, and chromium copper have been developed and used, but most of them do not meet all the necessary characteristics in terms of strength, electrical conductivity and heat resistance (softness). was a reality.

In order to develop alloys that can meet these industrial needs, the field of interest is ferrous-copper alloys. The reason is that copper (Cu) and iron (Fe) have little solid solubility with each other in a solid state at room temperature, that is, they do not mix, so that strength can be improved without loss of electrical conductivity. In addition, chromium (Cr) or beryllium (Be) in copper-chromium (Cu-Cr) and copper-beryllium (Cu-Be) alloys are elements that are harmful to the human body and cause environmental pollution problems. It is active.

C194 (Cu- 2.5 wt% Fe) iron-copper alloy developed as part of these efforts has been commercialized and is widely used in the form of plates. These iron-copper alloys have superior electrical conductivity compared to copper alloys for similar uses, but have a disadvantage in that the strength is lowered.

Currently, we are producing C194 level plates, but until recently, we have tried several times to develop iron-copper alloys with Fe content of 5 wt% or more. There are no success stories

On the other hand, in terms of demand, iron-copper alloy is a material that can replace copper-chromium (Cu-Cr), copper-beryllium (Cu-Be), copper-tin-phosphorus (Cu-Sn-P), etc., and is environmentally friendly, Domestic demand is estimated to be about 1000 tons/year or more.

An object of the present invention is to provide a material having high conductivity and high strength as a material for various electronic components applied to the mechanical field.

In order to solve the above technical problem, the present invention is a process of dissolving an iron-copper master alloy (Fe-Cu) material and pure copper (Cu) to form a molten metal, injecting the molten metal into a mold at an injection temperature of 1400 to 1600 ° C. A process of manufacturing an apron, a process of rolling the ingot at a rolling ratio of 40 to 60%, and drawing the rolled ingot at a reduction in area of 10 to 20%, and performing an annealing process between the drawing processes to make it thinner It is characterized in that it includes a process of

In addition, it is characterized in that the molten metal is applied by adding a grain refiner and B ₂ 0 ₃ during the formation of the molten metal.

In addition, the grain refiner includes potassium tetrafluoroborate (KBF₄) and zirconium fluoride (ZrF), characterized in that it is added in an amount of 0.5 to 0.9 wt%.

In addition, the drawing of (d) is characterized in that it is performed by changing the cross-sectional reduction ratio.

In addition, the annealing process of (d) is characterized in that it is performed at 500 to 600 ℃, 1 to 2 hours.

In addition, the thinning of (d) is characterized in that it is performed with a diameter of 0.5 to 0.7mm.

And 5 to 10 mass% of iron (Fe) and the balance is an alloy composition consisting of copper (Cu), the diameter is 0.5 to 0.7mm, the tensile strength is 60kg / mm ² or more, and the conductivity is 50 to 60% IACS, characterized in that the iron-copper alloy wire rod.

Through the above-described problem solving means, the present invention can provide a material suitable for each characteristic in the development of materials requiring high strength and high conductivity.

In addition, the present invention functions as a substitute for copper-beryllium (Cu-Be) and copper-chromium (Cu-Cr) alloys that cause environmental problems, thereby providing an eco-friendly material.

In addition, the present invention is advantageous in terms of economy by reducing dependence on imports of copper-beryllium (Cu-Be) and copper-chromium (Cu-Cr) alloys.

However, the effects that can be achieved by the high-strength, high-conductivity iron-copper wire and the method for manufacturing the same according to the embodiments of the present invention are not limited to those mentioned above, and other effects not mentioned are from the following description to which the present invention belongs. It will be clearly understood by those of ordinary skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included as a part of the detailed description to help the understanding of the present invention, provide embodiments of the present invention, and together with the detailed description, explain the technical spirit of the present invention.
1 is a flowchart illustrating a process for manufacturing an iron-copper wire rod according to the present invention.
2 shows the microstructure of the iron-copper alloy prepared without the addition of a particle refining agent or flux.
3 (a), (b), (c), (d) is the particle refining agent (KBF ₄ ) and ZrF) according to the amount of Cu-10 wt%.Fe.
4 (a), (b), (c), (d) shows the microstructure of Cu-10wt%.Fe according to the tapping temperature.
5 (a) to (g) show the microstructure of the iron-copper alloy according to the change in the iron (Fe) content.
6 is a graph showing changes in hardness and electrical conductivity according to iron (Fe) content.
7 (a), (b), (c), (d) shows the microstructure according to the reduction ratio in the Cu-10 wt% Fe alloy.
Figure 8 (a) shows the microstructure before heat treatment, (b) shows the microstructure after heat treatment.
9(a), (b), (c), and (d) are graphs showing changes in hardness and electrical conductivity according to holding time of specimens annealed at 400°C, 500°C, and 600°C after rolling.
10 shows the tensile strength and electrical conductivity of the drawn wire rod and the annealed wire rod.

The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that can be, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention, and do not represent all the technical spirit of the present invention, so they can be substituted at the time of the present application It should be understood that various equivalents and modifications may be made. Hereinafter, a high-strength, high-conductivity iron-copper wire and a manufacturing method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart illustrating a manufacturing process of an iron-copper wire according to the present invention.

Like the general manufacturing process, a melting process (S100), a rolling (extrusion) process (S200), a drawing process (S300), and a heat treatment process (S400) are performed.

In the melting process (S100), the enthalpy of the iron-copper alloy has a positive (+) value when the iron and copper are alloyed, so that phase separation is highly likely to occur depending on the casting conditions. That is, segregation may occur due to the density difference between the two elements. To solve the above problems, potassium tetrafluoroborate (KBF ₄ ) and zirconium fluoride (ZrF) were mixed and added (added) as a grain refiner, and to prevent oxidation, B ₂ O ₃ was used to dissolve the molten metal was applied to prevent oxidation of iron.

The microstructure of the iron-copper alloy prepared without the addition of a particle refining agent or a separate flux is shown in FIG. 2 . In this case, looking at the copper-iron (Cu-Fe) phase diagram shown in FIG. 2, the iron (Fe) component exists in a dendritic form (a shape extending into multiple strands like a tree branch) in the base of the copper (Cu) component, Some of them exist as large dendritic forms, suggesting that segregation is severe. Here, segregation refers to a state in which alloying elements or impurities are distributed in an unbalanced manner.

In the present invention, potassium tetrafluoroborate (KBF ₄ ) and zirconium fluoride (ZrF) particle refiner were added to improve the phenomenon of severe segregation as described above.

3 (a), (b), (c), and (d) show the microstructure of Cu-10 wt%.Fe according to the amount of the particle refiner (KBF ₄ and ZrF).

Potassium tetrafluoroborate (KBF ₄ ) and zirconium fluoride (ZrF) particle refining agents were added to investigate the refining and homogenizing effect of the iron phase. Specifically, Figure 3 shows the microstructure of the as-cast state of the Cu-10 wt% Fe alloy cast by adding particle refinement to 0.3 wt%, 0.5 wt%, 0.7 wt%, and 0.9 wt%, respectively.

3(a) shows a case in which the input amount of the particle refining agent is the smallest, that is, 0.3 wt%. In this case, the precipitated iron particles were formed relatively large compared to other cases, and some segregation was observed. However, when 0.5wt%, 0.7wt%, and 0.9wt% were added as shown in (b), (c), and (d) of FIG. 3, the iron (Fe) particles were relatively evenly dispersed and formed, and the size of the particles was also larger. It can be seen that it has been refined.

4 (a), (b), (c), (d) shows the microstructure of Cu-10 wt%.Fe according to the tapping temperature. To investigate the effect of the injection temperature of the molten metal into the mold on the segregation of iron particles, the homogeneity of the iron particles in the microstructure was investigated after injection at 1400°C, 1500°C, 1600°C, and 1700°C.

As shown in (a), (b), and (c) of FIG. 4 , in the case of injection temperatures of 1400° C., 1500° C., and 1600° C., iron (Fe) particles are relatively homogeneously distributed, but when injected at 1700° C. It can be seen that iron (Fe) particles were segregated, and the coarse iron particles had a distinct dendritic shape even at a magnification of 100 times.

As a preferred embodiment according to the present invention, in order to reduce segregation after dissolution, it may be carried out under the conditions of 0.5 wt% or more of particle refiners (KBF4 and ZrF) and a casting temperature of 1500°C.

In the production of this iron-copper alloy, pure copper and pure iron were melted in a crucible using alumina refractory material to prepare an alloy of Cu-10 wt% Fe composition, and then an ingot was prepared using a mold coated with alumina refractory material. The induction furnace used here was a 5 KHz, 150 KW induction melting furnace, and an ingot of Φ80 X 300 mm was manufactured using a mold. The material thus prepared was subjected to homogenization heat treatment at 600° C. for 10 hours and then put into extrusion.

In the extrusion process (S200), the homogenized ingot is heated in the atmosphere at 850° C. for 2 hours using a resistance heating furnace, and then extruded in Φ3.5 mm X 3 rows. At this time, the extrusion ratio was 174 and the extruder used was a direct type, and the capacity was 800 tons. Here, the extrusion ratio (extrusion ratio) is the ratio of the cross-sectional area of the material to the cross-sectional area of the extruded product, and if the reduction in area is R ₀ , the extrusion ratio is 1/(1-R ₀ ).

In the drawing process (S300), the drawing process was used to finally thin the wire of Φ3.5 mm manufactured through the extrusion process to Φ0.5 mm. The most important things in establishing the drawing process are the reduction in area and pass schedule for each cycle, and the annealing process conditions inserted during the process. This is because the present process is carried out under a cold working process. A wire drawing machine and an electric heating furnace for softening the work-hardened material during the drawing process were used in the annealing process.

The pass schedule used in the process according to the present invention is as follows.

Φ3.5 mm ==> Φ3.2 mm ==> Φ3.0 mm ==> Φ2.8 mm ==> Φ2.6 mm ==> Φ2.4 mm ==> Φ2.2 mm ==> Φ2 .0 mm ==> Φ1.8 mm ==> Φ1.6 mm ==> Φ1.5 mm ==> Φ1.4 mm ==> Φ1.3 mm ==> Φ1.2 mm ==>Φ1. 1 mm ==>Φ1.0 mm ==>Φ0.9 mm ==>Φ0.8 mm ==>Φ0.75 mm ==>Φ0.70 mm ==>Φ0.65 mm ==>Φ0.60 mm ==>Φ0.55 mm ==>Φ0.50 mm

That is, from Φ3.5 mm to Φ1.6 mm, the diameter was reduced by 0.2 mm, from Φ1.6 mm to Φ0.8 mm by 0.2 mm, and below that, the diameter was decreased by 0.1 mm to finally Φ0. A wire rod of .50 mm was prepared.

Annealing is to remove the heat history and processing effects remaining in the internal structure of the material by heating the metal material, and heat treatment to a certain temperature and then slowly cool it to correct the internal deformation of the metal (S400) one of the processes.

The annealing process was inserted during the process to recover the decrease in elongation due to work hardening, and was performed every 3 times up to Φ1.0 mm and every 2 times under Φ1.0 mm using a batch furnace after drawing. The annealing process conditions were maintained at 600 °C in the air for 1 hour and then air-cooled. At this time, a slight oxide layer was observed on the surface, but it was confirmed that it was removed in a subsequent process.

<Example>

dissolution of the test piece

Ferro-copper alloys for specimens of various compositions were manufactured using a 1kg-class small vacuum induction furnace. The induction furnace used in this experiment had a capacity of 10KW with a frequency of 10KHz. A graphite mold coated with paint was used for the mold, and it was processed to be cast in the form of a plate with a thickness of 18 mm. Copper (Cu) and iron (Fe) have a large melting point difference, and when heated to 1600°C for iron dissolution, iron may be oxidized depending on the degree of vacuum in the vacuum induction furnace. In order to solve this problem, since it is difficult to accurately match the iron content by slug heating, a master alloy with a composition of Cu-30wt%.Fe was prepared and used to adjust the iron content. The master alloy was prepared at about 30 kg.

In the operation of the vacuum induction furnace, an alumina crucible was used instead of the graphite crucible to prevent the graphite pick-up in iron. After filling an alumina crucible with pure copper (Cu) and a master alloy material of Cu-30wt%.Fe composition weighed to the desired content, start drawing a vacuum and start heating when it reaches 2.0 X 10 ^-2 torr, and when it reaches about 1400℃ it dissolves The molten metal thus prepared was cast into the prepared graphite mold under vacuum. After casting, the plate sample was heated at 900° C. for 6 hours using an atmospheric furnace for homogenization of the microstructure and then air-cooled.

rolled and drawing process

In order to manufacture a wire-shaped specimen, a plate-shaped ingot is rolled down to a thickness of 11 mm, and then cut into a 11 mm square, followed by die rolling, and rolled into a Φ4 mm wire. After the drawing process, wire rods up to Φ0.5mm are manufactured. Various necessary physical properties were measured using the above material. At this time, since the rolling or drawing process is a cold plastic working, an annealing process was performed at about 600° C. for about 1 hour for softening (a process in which a hard thing becomes soft) in the middle.

heat treatment process

The effect on changes in mechanical properties or changes in electrical conductivity according to the amount of cold working or heat treatment conditions was evaluated using the wire produced through the above process or the wire during the process. At this time, in order to change various heat treatment conditions, atmospheric tube furnaces or atmospheric box furnaces were used, and temperature was measured using R-type or K-type thermocouples.

<Test Example>

of iron-copper alloy Alloy design research

Through the above process, it is a wire for electronic components such as connector pins and heat-resistant springs with high conductivity and heat resistance, with a heat resistance temperature of 450 degrees or higher (this is a temperature at which 80% of the tensile strength at room temperature), a tensile strength of 60 kg/mm ² or more, Conductivity 50% IACS or more, stress relaxation resistance has characteristics of 80% or more, and it is possible to manufacture a Φ0.50 mm iron-copper alloy wire containing iron (Fe) of 10 mass% or more.

To investigate the effect of iron content on mechanical properties and electrical conductivity in iron-copper alloys, changes in microstructure, hardness, and electrical conductivity were measured while varying the iron content in the range of 7 wt% to 13 wt%. At this time, the iron content was used as a master alloy of Cu-30wt%Fe. Table 1 shows the target iron content and the composition of each alloy actually measured using ICP. Comparing the quantum values, it can be seen that the measured value of the content of iron (Fe) is smaller. The difference value is within about 0.5 wt%, and it can be seen that the difference decreases as the iron content increases.

ICP component analysis result of Cu-Fe alloy Goal setting (wt%) 7.0 8.0 9.0 10.0 11.0 12.0 13.0 Actual composition (wt%) 6.66 7.90 8.65 9.57 10.72 11.84 12.98

5 (a) to (g) show the microstructure of the iron-copper alloy according to the change in the iron (Fe) content.

The black particles shown in each image in FIG. 5 are iron (Fe) particles, and it can be seen that the iron (Fe) particles are relatively evenly distributed in each image. In addition, it can be seen that some iron particles are precipitated in a dendritic form, and it can be seen that the planar density of the dendritic phase increases as the iron content increases. On the other hand, since it is a cast structure, it is estimated that Cu, which is a matrix, contains as much iron as the solubility of iron (Fe) directly below the solidification temperature.

6 is a graph showing changes in hardness and electrical conductivity according to iron (Fe) content. Specifically, it shows how the Vicker's hardness value and electrical conductivity change according to the iron (Fe) content in the cast state. It can be seen that as the iron content increases, the hardness value increases while the electrical conductivity value decreases. The above results show that the increase in the content of iron (Fe) is due to the increase in the precipitated iron (Fe) particles, but also to the high capacity of iron (Fe) dissolved in the copper (Cu) matrix.

Compared to copper (Cu), iron (Fe) has a higher hardness value, but a significantly lower electrical conductivity. Therefore, as the iron content increases, the solid solution strengthening effect of the matrix increases and the overall hardness value increases due to the relatively high strength of the precipitated iron particles. This is because it also plays a role in lowering the electrical conductivity.

Plastic Processing Department Annealing Effect of Process Conditions on Hardness and Electrical Conductivity

7 (a), (b), (c), (d) shows the microstructure according to the reduction ratio in the Cu-10 wt% Fe alloy. Specifically, it shows how the casting structure changes according to the rolling rate for a specimen subjected to homogenization heat treatment after casting for Cu-10wt%Fe alloy.

As shown in (a) of Figure 7, in the case of 20% reduction, almost the cast dendritic structure remains as it is, but as the reduction amount increases, the dendritic iron (Fe) structure is pulverized and arranged parallel to the rolling direction. have.

8 (a), (b) shows the microstructure before and after heat treatment, respectively. When the material that has undergone rolling under 60% reduction is annealed at 500°C for 1 hour, as shown in FIG. Able to know. Therefore, it can be seen that the 60% cold-rolled iron-copper alloy is recrystallized at 500° C., and it can be seen that annealing is sufficiently performed at that temperature.

9 (a), (b), (c), and (d) are graphs showing changes in hardness and electrical conductivity according to holding time of specimens annealed at 400°C, 500°C, and 600°C after rolling. Specifically, when annealing at 400°C, 500°C, and 600°C for each material rolled at a reduction ratio of 20%, 40%, 60% and 80% with respect to Cu-10wt% Cu alloy, in each condition according to the annealing time It shows the change of hardness value and electrical conductivity.

Referring to FIG. 9 , it can be seen that basically, as the annealing temperature increases, the hardness decreases and the electrical conductivity increases. Looking at the hardness change, it can be seen that the hardness value decreases as the annealing time increases at all annealing temperatures. However, as for the degree of reduction, when the reduction amount is as small as 20%, the decrease in hardness value according to the change of the tested annealing temperature section or the holding time is negligible regardless of the annealing temperature.

However, as the rolling reduction gradually increases, the drop in the hardness value according to the holding time further increases. In the case of 40% and 60% reduction in reduction, the drop in 400°C and 500°C annealing is almost the same, and in the case of 600°C annealing, it significantly decreases, whereas in the case of 80% reduction, in the case of 400°C annealing, hardness according to holding time While the drop in value is insignificant, a significant decrease in hardness value can be observed in the holding time range tested in the case of annealing at 500°C and 600°C. This result is believed to be because the recrystallization temperature decreases as the reduction amount increases, and it can be estimated that the temperature drops below 500°C when the reduction is 80%.

On the other hand, it can be seen that the electrical conductivity increases when the holding time is long regardless of the annealing temperature for the rolled specimen for all rolling reductions. The above result is believed to be because, as annealing, iron (Fe) atoms that were dissolved in the copper (Cu) matrix are precipitated, so that the amount of dissolved iron (Fe) decreases as well as the density of dislocations decreases. In addition, in the case of all rolling reductions, the 500 °C annealing showed higher electrical conductivity values at all holding temperatures than the 400 °C and 600 °C annealing.

drawing in the wire According to the section reduction rate hardness value and Changes in electrical conductivity properties

10 shows the tensile strength and electrical conductivity of the drawn wire rod and the annealed wire rod. Tensile strength and electrical conductivity of the wire drawn with Φ1.2, 0.6, 0.5, and 0.4 mm and each wire annealed at 500 for 1 hour were measured, and the results shown in FIG. 10 were obtained.

In the case of the wire rod before annealing, it was confirmed that the tensile strength increased significantly as the cross-sectional area decreased, but the electrical conductivity decreased and did not reach the target value. It was confirmed that the tensile strength decreased by about 30kgf/mm² after annealing compared to before annealing. Through the above results, it can be seen that the work-hardened copper is recrystallized to significantly decrease the tensile strength, and the deformation of the copper inner lattice is reduced, thereby greatly increasing the electrical conductivity.

It can be seen that the optimization of cold plastic working and annealing processes is necessary to achieve the goal. Table 2 shows the results of measuring the change in electrical conductivity when the annealed Φ1.2mm wire was reduced by Φ0.1mm to achieve the above object.

Changes in electrical conductivity due to cross-section reduction after annealing Wire diameter (mm) 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 Electrical Conductivity (%IACS) 54.06 55.48 55.29 54.75 54.34 54.30 54.22 52.05

From Φ1.2mm to Φ0.6mm, the electrical conductivity is maintained almost the same without any drop as the amount of deformation increases until it reaches Φ0.6mm. These results show that the stretched iron (Fe) particles are stretched in one direction as the drawn amount increases, increasing the aspect ratio and decreasing the iron texture size of the cross-section, resulting in an effect of widening the diameter of copper through which electrons can move. As the free electron mobility increases, the electrical conductivity hardly decreases during a certain drawing process. As a result of the tensile test, the tensile strength of the Φ0.5mm wire was measured to be 66.21kgf/mm² and the electrical conductivity was measured to be 52.05 %IACS, which satisfies the target properties.

Characteristic evaluation method

microstructure

In order to see the change of microstructure according to various process conditions, a sample cut to an appropriate size is mounted, polished with sandpaper up to #1500, polished using 0.1㎛ alumina powder solution, and then 100ml of water + 30ml of hydrochloric acid + A mixed solution of 5 g of iron(II) chloride was used and etched for 1 to 3 minutes. The microstructure of the thus prepared specimen was observed at various magnifications using an optical microscope.

Hardness test and tensile test

To measure the hardness of the specimen, it was measured using a Vickers or micro Vickers hardness tester. Finally, the tensile strength evaluation of the wire rod or the wire rod manufactured using a mass production facility was measured using a wire rod tensile tester.

Measurement of electrical conductivity

The eddy-current method was initially used to measure electrical conductivity, but it was confirmed that it was not applied in alloys containing ferromagnetic materials such as iron due to the effect on the magnetic field. Therefore, the conductivity measurement method was changed to the double bridge method, and the electrical conductivity was measured by measuring the resistance value and converting the resistance value, the specific resistance according to the length and cross-sectional area of the conductor to the conductivity value.

Although representative embodiments of the present invention have been described in detail above, those of ordinary skill in the art to which the present invention pertains will understand that various modifications are possible within the limits without departing from the scope of the present invention with respect to the above-described embodiments. . Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims described below as well as the claims and equivalents.

Claims (7)

A process of forming a molten metal by dissolving an iron-copper master alloy (Fe-Cu) material and pure copper (Cu);
Addition of antioxidant B ₂ 0 ₃ to the molten metal, but 0.5 to 0.9 wt % of a grain refiner including potassium tetrafluoroborate (KBF₄) and zirconium fluoride (ZrF);
injecting the molten metal to which the grain refiner and the antioxidant additive are added into a mold to prepare an ingot;
rolling the ingot; and
The rolled ingot is drawn in a plurality of steps while reducing the diameter step by step, but whenever the number of steps of reducing the diameter reaches a predetermined number, an annealing process is inserted while drawing to form an iron-copper alloy wire rod. do,
The plurality of steps include a step in which the cross-sectional reduction rate is changed,
When drawing in the plurality of steps, after the diameter is reduced and reaches a predetermined diameter, reducing the number of steps of reducing the diameter than before reaching the predetermined diameter and inserting the annealing process,
Each of the annealing is performed at 500-600 ° C. for 1-2 hours,
The iron-copper alloy wire has a diameter of 1.0 mm or less containing 5 to 10 mass% of iron (Fe), the tensile strength of the iron-copper alloy wire is 60 kg/mm ² or more, and the conductivity is 50 to 60% IACS of the iron-copper alloy wire rod manufacturing method.
The method of claim 1,
A method of manufacturing an iron-copper alloy wire rod by injecting the molten metal into a mold and manufacturing the ingot by injecting the molten metal into the mold at an injection temperature of 1400 to 1600°C in the process of manufacturing the ingot.
The method of claim 1,
In the step of rolling the ingot, a method of manufacturing an iron-copper alloy wire rod by rolling the ingot at a rolling ratio of 40 to 60%.
The method of claim 1,
A method of manufacturing an iron-copper alloy wire rod drawn with a reduction in area of 10 to 20% in the plurality of steps. delete delete delete

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