Long composite material and manufacturing method of long composite material

Abstract

To provide a long composite material and a manufacturing method of the long composite material with which a long article formed of a plurality of materials can be stably manufactured and a degree of freedom of design is high.SOLUTION: A long composite material includes a plurality of core materials and a cylindrical tube member covering an outer peripheral surface of the plurality of core materials, the composite material being formed by wire drawing. At least one core material among the plurality of core materials is formed of a material different from that of other core materials. A filling rate of the plurality of core materials in a cross section of the tube member is equal to or greater than 97.5%. A ratio of an absolute value of a difference between a length of the shortest core material among the plurality of core materials and a length of the tube member with respect to the length of the tube member is equal to or less than 4.5%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a length of composite material and a method for producing a length of composite material. [Background technology]

[0002] Traditionally, components used in industrial products have often been made of a single material, such as carbon steel or aluminum alloy. However, in recent years, due to increasing demands on industrial products, it has become difficult for a single material to meet the required performance. Therefore, many industrial products have begun to use composite materials, which are made up of multiple materials, rather than a single material.

[0003] Clad materials have been attracting attention as composite materials. The material properties of clad materials can be changed by changing the types and proportions of the constituent materials. For example, Patent Document 1 discloses a magnesium-clad cord including a first wire made of magnesium or a magnesium alloy and a second wire made of a different metal (a metal different from both magnesium and a magnesium alloy) that is annularly disposed around the first wire and extends spirally in the longitudinal direction of the first wire.

[0004] In recent years, there has been a demand for composite materials (multi-property materials) that can achieve desired performance by designing them through optimization of the selection and arrangement of materials used (topology optimization). However, Patent Document 1 does not disclose anything about such multi-property materials.

[0005] On the other hand, with regard to multi-property materials, for example, Patent Document 2 discloses a technology for appropriately arranging multiple materials to produce a clad material with desired properties through extrusion processing with high precision in a short time. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-76490 A [Patent Document 2] International Publication No. 2023 / 063185 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the extrusion processing technique described in Patent Document 2 has the problem that it is difficult to obtain a long composite material, and is therefore unsuitable for industrial continuous production.

[0008] Therefore, the present invention has been made in consideration of the above circumstances, and aims to provide a long composite material and a method for manufacturing a long composite material that can stably manufacture long products made of multiple materials and has a high degree of design freedom. [Means for solving the problem]

[0009] As a result of extensive research to solve the above problems, the present inventors have found that the above problems can be solved by the following configuration, and have completed the present invention through further research based on this finding.

[0010] A long composite material according to one embodiment of the present invention is a long composite material that has been drawn and comprises a plurality of core materials and a cylindrical tubular material covering the outer surfaces of the plurality of core materials, wherein at least one of the plurality of core materials is made of a material different from the other core materials, the filling rate of the plurality of core materials in the cross section of the tubular material is 97.5% or more, and the ratio of the absolute value of the difference between the length of the shortest core material among the plurality of core materials and the length of the tubular material to the length of the tubular material is 4.5% or less.

[0011] Another aspect of the present invention relates to a method for manufacturing a long composite material, which method comprises inserting multiple core materials into a cylindrical tubular material and performing a wiredrawing process, wherein at least one of the multiple core materials is composed of a material different from the other core materials, the multiple core materials have a multilayer structure of two or more layers in the cross section of the tubular material, the multilayer structure has at least one inner layer composed of at least one core material and an outermost layer composed of two or more core materials, the average hardness of the core material constituting the outermost layer is greater than or equal to the average hardness of the core material constituting the inner layer, the void ratio within the tubular material before the wiredrawing process is 15.5% or less, and the area reduction rate during the wiredrawing process is 20% or more.

[0012] A method for manufacturing a long composite material according to yet another embodiment of the present invention is a method for manufacturing a long composite material, which comprises inserting multiple core materials into a cylindrical tubular material and performing a wiredrawing process, wherein at least one of the multiple core materials is composed of a material different from the other core materials, the multiple core materials have a multilayer structure of two or more layers in the cross-section of the tubular material, the multilayer structure has at least one inner layer composed of at least one core material and an outermost layer composed of two or more core materials, the average hardness of the core material constituting the outermost layer is lower than the average hardness of the core material constituting the inner layer, the void ratio within the tubular material before the wiredrawing process is 8.5% or less, and the area reduction rate in the wiredrawing process is 30% or more. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a long composite material and a method for manufacturing a long composite material that can stably manufacture long products made of multiple materials and has a high degree of design freedom. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view showing an example of the arrangement of a plurality of core materials in a tubular material before wire drawing of a long composite material according to one embodiment of the present invention. [Figure 2]FIG. 2 is a cross-sectional view showing another example of the arrangement of a plurality of core materials in a tubular material before wire-drawing of a long composite material according to one embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing cross-sectional views of Examples 1 to 5 and Comparative Examples 1 to 11 before and after pre-processing. [Figure 4] FIG. 4 is a schematic diagram illustrating that when a core material is arranged as shown in FIG. 1, drawing causes misalignment at the end due to the material and arrangement of the core material. [Figure 5] FIG. 5 is a diagram showing the relationship between the void ratio and the rear end displacement rate in the composite materials of Examples 1 and 2 and Comparative Examples 1 and 2. [Figure 6] FIG. 6 is a diagram showing the relationship between the void ratio and the rear end displacement rate in the composite materials of Examples 3 and 4 and Comparative Example 4. [Figure 7] FIG. 7 is a diagram showing the relationship between the void ratio and the rear end displacement rate in the composite materials of Comparative Examples 5 to 8. [Figure 8] FIG. 8 is a diagram showing the relationship between the void ratio and the rear end displacement rate in the composite materials of Example 5 and Comparative Examples 9 to 11. [Figure 9] FIG. 9 is a diagram showing cross-sectional views before and after pre-processing in Examples 6 to 10 and Comparative Examples 12 to 23. [Figure 10] FIG. 10 is a schematic diagram illustrating that when a core material is arranged as shown in FIG. 2, punching causes misalignment at the end due to the material and arrangement of the core material. [Figure 11] FIG. 11 is a diagram showing the relationship between the void ratio and the rear end displacement rate in the composite materials of Examples 6 and 7 and Comparative Examples 12 and 13. [Figure 12] FIG. 12 is a diagram showing the relationship between the void ratio and the rear end displacement rate in the composite materials of Examples 8 and 9 and Comparative Examples 14 and 15. [Figure 13] FIG. 13 is a diagram showing the relationship between the void ratio and the rear end displacement rate in the composite materials of Comparative Examples 16 to 19. [Figure 14] FIG. 14 is a diagram showing the relationship between the void ratio and the rear end displacement rate in the composite materials of Example 10 and Comparative Examples 20 to 23. [Figure 15]FIG. 15 is a diagram showing a cross section of the drawn material obtained in Test Example 2. [Figure 16] FIG. 16 is a diagram showing the measured and calculated values ​​of the density of the drawn material obtained in Test Example 2. [Figure 17] FIG. 17 is a diagram showing the measured values ​​and calculated values ​​of the tensile strength of the drawn material obtained in Test Example 2. [Figure 18] FIG. 18 is a diagram showing the measured values ​​and calculated values ​​of Young's modulus of the drawn material obtained in Test Example 2. [Figure 19] FIG. 19 is a diagram showing the measured and calculated electrical resistivities of the drawn material obtained in Test Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these.

[0016] [Composite materials] The long composite material according to this embodiment is a wire-drawn long composite material comprising multiple core materials and a cylindrical tubular material covering the outer surfaces of the multiple core materials, wherein at least one of the multiple core materials is made of a different material from the other core materials, the filling rate of the multiple core materials in the cross section of the tubular material is 97.5% or more, and the ratio of the absolute value of the difference between the length of the shortest core material among the multiple core materials and the length of the tubular material to the length of the tubular material is 4.5% or less. This configuration allows for the stable production of long products made of multiple materials, and allows for the production of long composite materials with a high degree of design freedom.

[0017] The length of the long composite material in this embodiment is not particularly limited as long as it is a length that can generally be considered long. An example of a long composite material is a composite material with a length of 10 m or more.

[0018] By manufacturing the composite material using wiredrawing, it is possible to stably manufacture long products compared to manufacturing using extrusion. The method of wiredrawing in this embodiment is not particularly limited, and examples thereof include, similar to known wiredrawing methods, a method in which multiple core materials are inserted into a tubular material, which is then drawn using a die, and wiredrawing is performed in multiple stages until a composite material of a predetermined length and diameter is obtained. More specifically, wiredrawing may be performed using the wiredrawing method described in [Method for manufacturing a composite material] below.

[0019] In the long composite material, by having the filling rate of the multiple core materials in the cross section of the tubular material be 97.5% or more, long products can be stably manufactured even if the composite material is composed of multiple materials. The filling rate is preferably 99.0% or more. Furthermore, there is no particular upper limit to the filling rate, and the filling rate is preferably close to 100%.

[0020] The filling rate can be measured, for example, by the following method. First, a cross-sectional photograph of the composite material is imported into image processing software ImageJ. Next, the area of ​​the interior of the tubular material and the area of ​​the voids between multiple core materials are measured, and the filling rate is calculated as (1 - interior area / void area) x 100.

[0021] In the long composite material, the ratio of the absolute value of the difference between the length of the shortest core material among the plurality of core materials and the length of the tube material to the length of the tube material is 4.5% or less, preferably 3.5% or less, and more preferably 2.5% or less.

[0022] When multiple core materials, including two or more core materials made of different materials, are drawn together, the elongation rate of each core material during the drawing process may differ depending on the deformation characteristics of the materials used for each core material and the arrangement of each core material, and the length of at least one core material may become shorter than the length of the tubular material. This may result in non-uniform deformation of the composite material after the drawing process. However, if the ratio of the absolute value of the difference between the length of the shortest core material among the multiple core materials and the length of the tubular material is 4.5% or less, this means that almost no non-uniform deformation occurs due to the drawing process, and long products can be reliably obtained even from composite materials made of multiple materials.

[0023] As mentioned above, non-uniform deformation due to wiredrawing occurs when the length of at least one core material is shorter than the length of the tubular material. Therefore, it is preferable that the lengths of all core materials are the same as or longer than the length of the tubular material after wiredrawing. When the lengths of all core materials are longer than the length of the tubular material after wiredrawing, even if the ratio of the absolute value of the difference between the length of the shortest core material among the multiple core materials and the length of the tubular material to the length of the tubular material is greater than 4.5%, it can be said that non-uniform deformation due to wiredrawing has hardly occurred. In other words, when the lengths of all core materials are the same as or longer than the length of the tubular material after wiredrawing, long products can be reliably obtained even for composite materials composed of multiple materials.

[0024] The difference between the length of each of the multiple core materials and the length of the tubular material can be measured, for example, by inserting a thin wire into the end of the tubular material, as described in the examples below.

[0025] (multiple core materials) At least one of the plurality of core materials is made of a material different from the other core materials, thereby making it possible to obtain a long composite material made of a plurality of materials. As long as at least one of the plurality of core materials is made of a material different from the other core materials, the material, dimensions, length, cross-sectional shape, number of core materials, etc. of each core material are not particularly limited.

[0026] The materials (substances) that can be used to form the plurality of core materials include, for example, copper, aluminum, iron, magnesium, silver, titanium, zinc, and alloys of these.

[0027] The number of types and strands of materials used as the multiple core materials is preferably equal to or greater than the number of desired composite material properties. Specifically, if the desired composite material has three specified properties, namely, density, tensile strength, and electrical resistivity, it is preferable to use at least one strand of each of the three core materials, for example, aluminum, iron, and copper. This makes it easier to obtain each desired property.

[0028] Generally, various properties of composite materials are predicted by the rule of mixtures described below, and specifically, each property is determined by a regression equation in which the factors are the individual physical properties of the materials that make up the composite material and their ratios. Therefore, in order to achieve highly accurate optimization, it is necessary to increase the number of factors used in the design, and highly accurate optimization can be achieved by setting the number of types and numbers of materials of the multiple core materials to be equal to or greater than the number of desired properties.

[0029] (pipe material) The pipe material is cylindrical, and the diameter, dimensions, cross-sectional shape, material, etc. of the pipe material are not particularly limited.

[0030] The cross-sectional shape of the tubular material is preferably, for example, a circle or a polygon. Examples of polygonal shapes include a triangle, a rectangle, a hexagon, etc. When the cross-sectional shape of the core material is a polygon, it is preferably a regular polygon.

[0031] The material (quality of material) of the pipe may be, for example, copper, aluminum, iron, magnesium, silver, titanium, zinc, or alloys thereof.

[0032] It is preferable that the deformation resistance of the tubular material is greater than the deformation resistance of at least one of the core materials among the plurality of core materials. By using such a tubular material, breakage of the tubular material during wire drawing can be suppressed and uniform deformation can be achieved.

[0033] In the composite material, the mixing ratio of the core materials to the tubular material is not particularly limited and is determined, for example, by the inner and outer diameters of the tubular material used and the number and diameter of the core materials used. The diameter size of the core materials is determined by the processing conditions of the wire drawing process (such as the area reduction rate and the number of repetitions), which will be described later.

[0034] [Method of manufacturing composite materials] The method for producing a long composite material in this embodiment will be described below, but the present invention is not limited thereto.

[0035] As mentioned above, when multiple core materials, including two or more core materials made of different materials, are drawn together, the elongation rate of each core material during the drawing process differs depending on the differences in the deformation characteristics of the materials used for each core material and the arrangement of each core material. This causes the length of each core material to be shorter than the length of the tube material, resulting in defects such as sagging of the outer layer wire and breakage of the inner layer wire.

[0036] Therefore, the inventors conducted extensive research to solve these problems, and discovered that by adjusting the arrangement (insertion position) of the multiple core materials within the tubular material, the void ratio within the tubular material before the wiredrawing process, and the area reduction rate during the wiredrawing process, it is possible to suppress the occurrence of uneven deformation due to the wiredrawing process, thereby enabling the stable production of long composite materials and the production of long composite materials with a high degree of design freedom.

[0037] In this embodiment, a method for producing a long composite material involves inserting multiple core materials into a cylindrical tubular material and drawing them, wherein at least one of the multiple core materials is made of a different material than the other core materials, and the multiple core materials have a multilayer structure of two or more layers in the cross section of the tubular material, with the multilayer structure including at least one inner layer made of at least one core material and an outermost layer made of two or more core materials. [1] If the average hardness of the core material making up the outermost layer is equal to or greater than the average hardness of the core material making up the inner layer, the porosity within the tubular material before the wiredrawing is 15.5% or less, and the area reduction rate during the wiredrawing is 20% or more. [2] If the average hardness of the core material making up the outermost layer is lower than the average hardness of the core material making up the inner layer, the porosity within the tubular material before the wiredrawing is 8.5% or less, and the area reduction rate during the wiredrawing is 30% or more. The method for producing the composite material is described in detail below.

[0038] (Preparation of multiple core materials and tube materials) First, a plurality of core materials and tube materials to be used in the manufacturing method of a long composite material in this embodiment are prepared. The plurality of core materials before the wiredrawing process are not particularly limited in terms of the cross-sectional shape, cross-sectional dimensions, length, material, and number of core materials, as long as at least one core material among the plurality of core materials is made of a material different from the other core materials. By making at least one core material among the plurality of core materials made of a material different from the other core materials, a long composite material made of a plurality of materials can be obtained.

[0039] Before the wire drawing process, the material (quality of material) and number of core materials constituting each core material can be explained in the same manner as in the explanation of the plurality of core materials in the above-mentioned [composite material].

[0040] Before the wire drawing process, the cross-sectional shape of each core material is not particularly limited, but is preferably circular or polygonal. The outer circumferential surfaces of the core materials are preferably covered with a cylindrical tubular material, and the core materials are preferably inserted as many as possible into the tubular material with as few gaps as possible. Furthermore, it is preferable that each core material has a simple cross-sectional shape, which is easy to manufacture. In consideration of these points, the cross-sectional shape is preferably circular or polygonal. Examples of polygonal shapes include triangles, rectangles, and hexagons. If the cross-sectional shape is polygonal, it is preferably a regular polygon.

[0041] Before the wire drawing process, the cross-sectional size of each core material is not particularly limited, but is preferably 0.1 to 5.0 mm.

[0042] Before the wire drawing process, the length of each core material is not particularly limited and can be changed depending on the desired length of the composite material, and is preferably, for example, 400 mm or more.

[0043] Before the wire drawing process, the cross-sectional shapes, cross-sectional dimensions, and lengths of the core materials may be different or the same, but it is preferable to use core materials with the same cross-sectional shapes, cross-sectional dimensions, and lengths, which is thought to make it easier to predict the properties of the composite material and improve the prediction accuracy.

[0044] It is preferable to use wire material as the multiple core materials. With this configuration, it is possible to insert a large number of small-diameter core materials into the tubular material, making it easier to obtain characteristics close to the required characteristics. Furthermore, wire material has the advantage of being easy to manufacture and readily available from outside. Although round wire material is preferable as the wire material, wire material with a cross section of a triangle, square, hexagon, etc. may also be used.

[0045] As long as the tubular material before the wire drawing process is cylindrical, various conditions of the tubular material, such as the diameter, cross-sectional shape, length, material, etc., are not particularly limited. The cross-sectional shape and material of the tubular material can be explained in the same manner as the explanation of the tubular material in the above-mentioned [Composite Material].

[0046] Before the wire drawing process, the outer diameter of the tubular material is preferably φ1.5 mm to φ15.0 mm, and the inner diameter of the tubular material is preferably φ0.5 mm to φ12.0 mm.

[0047] Before the wire drawing process, the length of the tube material is preferably 400 mm or more.

[0048] (Insertion of core material) Next, multiple core materials are inserted (arranged) into a cylindrical tubular material. Specifically, the multiple core materials are inserted so that the tubular material has a multilayer structure of two or more layers in its cross section. The multilayer structure has at least one inner layer composed of at least one core material and an outermost layer composed of two or more core materials. Specific examples of the multilayer structure include those shown in Figures 1 and 2. Figures 1 and 2 show cross-sectional views illustrating an example of the arrangement of the multiple core materials within the tubular material before wiredrawing of the composite material. For example, in Figure 1, one first-layer (inner layer) core material F1 is arranged in the center of the tubular material, six second-layer (inner layer) core materials F2 are arranged around the first-layer core material, and 12 third-layer (outermost layer) core materials F3 are arranged around the second-layer core material. Also, for example, in Figure 2, one first layer (inner layer) core material F4 is placed in the center of the pipe material, and six second layer (outermost layer) core materials F5 are placed around the first layer core material.

[0049] In the multilayer structure, the material of the core material arranged in each layer may be the same as or different from the material of the core material arranged in the other layers. Furthermore, when two or more core materials are arranged in the same layer, the materials of the core materials in the same layer may be the same as or different from each other.

[0050] The core materials in the tubular material are preferably arranged in positions that are symmetrical about the center of the tubular material. This suppresses the occurrence of non-uniform deformation during wire drawing. Furthermore, composite materials without deviations in properties can be easily manufactured. When the tubular material is cylindrical, the core materials are preferably arranged concentrically about the center of the tubular material.

[0051] [1] The above-mentioned "the average hardness of the core material constituting the outermost layer is equal to or greater than the average hardness of the core material constituting the inner layer" means, specifically referring to Figure 1, that the average hardness of the 12 core materials F3 in the third layer is equal to or greater than the average hardness of the total seven core materials: the core material F1 in the first layer and the six core materials F2 in the second layer. In this case, the porosity within the pipe material is set to 15.5% or less. The porosity is preferably set to 14.0% or less, and more preferably to 12.0% or less. Meanwhile, there is no particular limit to the lower limit of the porosity, and the closer to 0%, the better.

[0052] [2] The above-mentioned "the average hardness of the core material constituting the outermost layer is lower than the average hardness of the core material constituting the inner layer" means, specifically, with reference to Figure 1, that the average hardness of the 12 core materials F3 in the third layer is lower than the average hardness of the total seven core materials: the core material F1 in the first layer and the six core materials F2 in the second layer. In this case, the porosity within the pipe material is set to 8.5% or less. Meanwhile, there is no particular lower limit for the porosity, and the closer to 0%, the better.

[0053] The average hardness can be calculated using the hardness of each core material measured by a Vickers hardness test. Specifically, the Vickers hardness is measured at three points in the center of the cross section of each core material, and the average value is used as the hardness of each core material. From the results, the average hardness of the core material constituting the outermost layer in the multilayer structure and the average hardness of the core material constituting the inner layer are calculated.

[0054] The porosity can be calculated by measuring the area of ​​the interior of the tube and the area of ​​the core material from a cross-sectional view of the tube using image processing software ImageJ. The porosity can be adjusted, for example, by adjusting the number and dimensions of the core materials, the inner diameter of the tube, etc. Alternatively, the porosity can be adjusted by passing the tube with multiple core materials inserted through a drawing die and pre-processing it before wiredrawing.

[0055] (Wire drawing process) Subsequently, a plurality of core materials are inserted into a cylindrical tubular material and then subjected to wire drawing (drawing), thereby obtaining a long composite material.

[0056] The wire drawing process can be performed by, for example, a known process using a die. Specific examples of the wire drawing method include a method in which the core materials are inserted into the cylindrical tubular material in a predetermined arrangement and then drawn through a die hole.

[0057] As described above, [1] the average hardness of the core material constituting the outermost layer is equal to or greater than the average hardness of the core material constituting the inner layer, and when the porosity within the tubular material is set to 15.5%, and the multiple core materials are inserted into the tubular material and then wiredrawn, the area reduction rate in the wiredrawing is set to 20% or more. This configuration prevents non-uniform deformation caused by the wiredrawing process, enabling the stable production of long composite materials. On the other hand, the area reduction rate is preferably set to 45% or less, and more preferably 30% or less. By setting the area reduction rate to 45% or less, the risk of wire breakage can be reduced.

[0058] As described above, [2] when the average hardness of the core material constituting the outermost layer is lower than the average hardness of the core material constituting the inner layer, the porosity within the tubular material is 8.5%, and the multiple core materials are inserted into the tubular material and then wiredrawn, the area reduction rate in the wiredrawing is 30% or more. This configuration prevents non-uniform deformation caused by the wiredrawing process and enables the stable production of long composite materials. On the other hand, it is preferable that the area reduction rate is 45% or less. By setting the area reduction rate to 45% or less, the risk of wire breakage can be reduced.

[0059] The number of times the wiredrawing is performed is not particularly limited, and the wire can be drawn multiple times until a composite material of a predetermined length and thickness is obtained. When the wiredrawing is performed multiple times, the above-mentioned "area reduction rate in the wiredrawing" means the area reduction rate in the first wiredrawing (initial wiredrawing rate).

[0060] Multi-Property Materials In the method for manufacturing a long composite material according to this embodiment, it is preferable to manufacture a long composite material having desired properties by adjusting the combination of the tubular material and the multiple core materials, inserting the multiple core materials into the tubular material, and then performing a wiredrawing process. This configuration allows for the production of a composite material (multi-property material) with desired performance, enabling a design that does not require optimization of material selection or placement. Below, we will specifically explain how to predict the properties of a composite material and adjust the combination of the tubular material and the multiple core materials.

[0061] (characteristics prediction) There are two types of methods for predicting the properties of composite materials used to manufacture composite materials with desired properties: a prediction method based on the physical properties of the core material and the tube material, and a prediction method based on an analysis of the properties of a composite material that has already been manufactured.

[0062] Prediction based on the properties of the core and pipe materials It is preferable to predict the properties of the composite material obtained by combining multiple core materials and tube materials based on the physical properties of the core material and the tube material, and then, by referring to the prediction, determine the combination of multiple core materials and tube materials necessary to obtain a composite material with the desired properties, and insert the multiple core materials into the tube material as determined and perform wire drawing, thereby producing a composite material with the desired properties.

[0063] In this way, by predicting the properties of the composite material based on the physical properties of the core material and the physical properties of the tube material, and determining the combination of multiple core materials and tube materials by referring to the predictions, composite materials with the desired properties can be manufactured efficiently and accurately.

[0064] As a specific prediction method, the rule of mixtures (rule of mixtures) is preferred because it allows for easy prediction. An example of a method for predicting the density, tensile strength, Young's modulus, and electrical resistivity of a composite material using the rule of mixtures will be described below. It is assumed that, before wire drawing, a plurality of core materials have a three-layer structure in the cross section of the pipe material, with the first layer (inner layer) core material F1 being aluminum (Al), the second layer (inner layer) core material F2 being iron (Fe), and the third layer (outermost layer) core material F3 being copper (Cu).

[0065] (1) Area ratio To predict the properties of composite materials, the arithmetic mean (rule of mixtures) weighted by the cross-sectional area before wire drawing is generally used.

[0066] Assuming that the tube material and core material are uniformly deformed during wire drawing, the area ratio of the tube material after wire drawing, f s , and the area ratio of the core material after wire drawing f c , and the area ratio of one core material after wire drawing f f where n is the number of core materials, d0 is the outer diameter of the pipe material (mm), and d i is the inner diameter of the pipe (mm), d f When is the diameter of the core material (mm), it can be calculated using the following formula.

[0067] f s =(d0 2 -d i 2 ) / (d0 2 -d i 2 +nd f 2 ) f c =nd f 2 / (d0 2 -d i 2 +nd f 2 ) f f =d f 2 / (d0 2 -d i 2 +nd f 2 )

[0068] (2) Density The density ρ of the composite material is ρ s is the density of the pipe material, ρ c is the density of the core material, f c is the area ratio of one core material, ρ Al , ρ Fe , ρ Cu are the densities of aluminum (Al), iron (Fe), and copper (Cu), respectively, and n Al , n Fe , n Cu When these are the numbers of Al core materials, Fe core materials, and Cu core materials, respectively, they can be predicted by the following formula.

[0069] ρ=ρ s f s +ρ c f c =ρ s f s +ρ Al n Al f f +ρ Fe n Fe f f +ρ Cu n Cu f f

[0070] (3) Tensile strength The tensile strength σ of a composite material is σ s is the tensile strength of the pipe material, σ c is the tensile strength of the core material, σ Al , σ Fe , σ Cu are the tensile strengths of Al, Fe, and Cu, respectively, and are predicted by the following formula:

[0071] σ=σ s f s +σ c f c =σ s f s +σ Al n Al f f +σ Fe n Fe f f +σCu n Cu f f

[0072] (4) Young's modulus The Young's modulus E of a composite material is E s is the Young's modulus of the pipe material, E c is the Young's modulus of the core material, E Al , E Fe , E Cu are the Young's moduli of Al, Fe, and Cu, respectively, and are predicted by the following formula:

[0073] E=E s f s +E c f c =E s f s +E Al n Al f f +E Fe n Fe f f +E Cu n Cu f f

[0074] (5) Electrical resistivity The electrical resistivity κ of the composite material is calculated by assuming that the tube material and all core materials are connected in parallel. s is the electrical resistivity of the pipe material, κ Al , κ Fe , κ Cu are the electrical resistivities of Al, Fe, and Cu, respectively, and are predicted by the following formula:

[0075] 1 / κ=f s / κ s +(n Al / κ Al +n Fe / κ Fe +n Cu / κ Cu )f f

[0076] Although the above prediction uses a method that uses the mixture rule, machine learning may also be used. Highly accurate predictions can be achieved by using machine learning. Known methods for machine learning include supervised learning such as neural networks and deep learning, and unsupervised learning such as clustering.

[0077] Prediction based on analysis of the properties of previously manufactured composite materials When manufacturing a composite material using the manufacturing method of this embodiment, it is preferable to analyze the characteristics of a composite material previously manufactured using the manufacturing method, change the combination of the tubular material and multiple core materials used to manufacture the previously manufactured composite material based on the analysis, and determine the combination of the multiple core materials and tubular material based on the changed combination, and then perform wire drawing to manufacture a composite material with the desired characteristics.

[0078] By analyzing the properties of a composite material that has been previously manufactured, it is possible to easily adjust the combination of multiple core materials and tube materials in order to manufacture a composite material with the desired properties.

[0079] (Combinations of multiple core materials and pipe materials) The combination of multiple core materials and pipe materials is preferably a combination of the material of the pipe material, the number of core materials, the material of each of the multiple core materials, and the insertion position of each of the multiple core materials into the pipe material. By combining the material of the pipe material, the number of core materials, the material of each of the multiple core materials, and the insertion position of each of the multiple core materials into the pipe material, it is possible to accommodate most composite materials with desired properties, and by limiting them to these, prediction, design, and manufacturing can be carried out quickly and efficiently.

[0080] (Manufacturing flow for multi-property materials) As described above, by predicting the properties of a composite material, it is possible to manufacture a long composite material (multi-property material) having desired properties. An example of a manufacturing flow of a composite material in this embodiment will be described below.

[0081] (1) Basic design of the product First, the basic design of the product is done.

[0082] (2) Specifying dimensions and characteristics of components Next, the dimensions and characteristics of the components required for the product are specified.

[0083] (3) Determining manufacturing conditions Next, based on the specified characteristics and the outer diameter of the pipe, the inner diameter of the pipe, the alignment and number of cores to be inserted, the type of material for the pipe and core, and the insertion position (positioning position) of the core are determined, and the core placement is determined. In addition, the outer diameter of the pipe is selected, and the wire drawing conditions, such as the wire drawing equipment, area reduction rate, speed, lubrication, and die angle, are set, and the wire drawing conditions are determined.

[0084] (4) Manufacturing of composite materials Based on the combination of the plurality of core materials and the pipe material determined above, the plurality of core materials are inserted into the pipe material, and wire drawing is performed under the conditions determined above to produce a composite material.

[0085] (5) Check the dimensions and properties of the composite material Finally, the dimensions and properties of the manufactured composite material are checked, and if there are no problems, the composite material is shipped to the destination where it is subjected to secondary processing and used for various purposes.

[0086] It should be noted that the scope of the present invention also includes a long composite material obtained by the above-described manufacturing method.

[0087] As described above, this specification discloses various aspects of the technology, but the main technologies among them are summarized below.

[0088] In the first aspect, the long composite material is a long composite material that has been wire-drawn and comprises multiple core materials and a cylindrical tubular material covering the outer surfaces of the multiple core materials, wherein at least one of the multiple core materials is made of a material different from the other core materials, the filling rate of the multiple core materials in the cross section of the tubular material is 97.5% or more, and the ratio of the absolute value of the difference between the length of the shortest core material among the multiple core materials and the length of the tubular material to the length of the tubular material is 4.5% or less.

[0089] In a second aspect, the long composite material is the long composite material of the first aspect, wherein the filling rate is 99.0% or more.

[0090] In a third aspect, a method for manufacturing a long composite material is a method for manufacturing a long composite material, in which multiple core materials are inserted into a cylindrical tubular material and subjected to wire drawing, wherein at least one of the multiple core materials is composed of a material different from the other core materials, the multiple core materials have a multilayer structure of two or more layers in the cross section of the tubular material, the multilayer structure has at least one inner layer composed of at least one core material and an outermost layer composed of two or more core materials, the average hardness of the core material constituting the outermost layer is greater than or equal to the average hardness of the core material constituting the inner layer, the void ratio within the tubular material before the wire drawing is 15.5% or less, and the area reduction rate during the wire drawing is 20% or more.

[0091] In a fourth aspect, a method for manufacturing a long composite material is a method for manufacturing a long composite material, in which multiple core materials are inserted into a cylindrical tubular material and drawn, wherein at least one of the multiple core materials is made of a material different from the other core materials, the multiple core materials have a multilayer structure of two or more layers in the cross section of the tubular material, the multilayer structure has at least one inner layer made of at least one core material and an outermost layer made of two or more core materials, the average hardness of the core material making up the outermost layer is lower than the average hardness of the core material making up the inner layer, the void ratio within the tubular material before the wiredrawing process is 8.5% or less, and the area reduction rate in the wiredrawing process is 30% or more.

[0092] The fifth aspect of the method for producing a long composite material is the same as the third or fourth aspect of the method for producing a long composite material, in which the combination of the tubular material and the multiple core materials is adjusted, the multiple core materials are inserted into the tubular material, and then the material is drawn to produce a long composite material having the desired properties.

[0093] The sixth aspect of the method for manufacturing a long composite material is the fifth aspect of the method for manufacturing a long composite material, in which the combination of the tubular material and the multiple core materials is a combination of the material constituting the tubular material, the number of the multiple core materials, the material constituting each of the multiple core materials, and the insertion position of each of the multiple core materials into the tubular material.

[0094] A seventh aspect of the method for producing a long composite material is the method for producing a long composite material according to any one of the third to sixth aspects, wherein the plurality of core materials are inserted at positions that are symmetrical about an axis.

[0095] In the eighth aspect, the method for producing a long composite material is the method for producing a long composite material in any one of the third to seventh aspects, wherein the number of the multiple core materials is equal to or greater than the number of desired properties of the composite material.

[0096] A ninth aspect of the method for producing a long composite material is the method for producing a long composite material according to any one of the third to eighth aspects, wherein the cross-sectional shape of the core material is circular or polygonal.

[0097] A tenth aspect of the method for producing a long composite material is the method for producing a long composite material according to any one of the third to ninth aspects, wherein the core material is a wire material.

[0098] In the 11th aspect, the method for manufacturing a long composite material is the method for manufacturing a long composite material in any one of the third to tenth aspects, wherein the deformation resistance of the tubular material is greater than the deformation resistance of at least one of the multiple core materials.

[0099] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples in any way. [Example]

[0100] <Test Example 1> A long composite material according to this embodiment was produced on a laboratory scale as follows.

[0101] [Examples 1 to 5, Comparative Examples 1 to 11] First, the pipe materials and core materials used in Examples 1 to 5 and Comparative Examples 1 to 11 will be described below.

[0102] The pipe material used was a pure copper pipe (C1020-H) with an outer diameter of φ11, an inner diameter of φ8, and a length of 650 mm.

[0103] Three types of wire were used for the core material: pure copper wire (C1020W-O), pure aluminum wire (A1070-O), and ordinary iron wire (SWM-B (SWRM6)).The dimensions of each wire were φ1.5 in diameter and 650 mm in length.

[0104] As shown in Figure 1, 19 cores were arranged in a regular pattern inside the copper pipe. The central core is called the first layer (inner layer), the six adjacent cores are called the second layer (inner layer), and the 12 surrounding cores are called the third layer (outermost layer). Cores of the same material were arranged within each layer, and two combinations of materials were used: core F1 for the first layer, core F2 for the second layer, and core F3 for the third layer: ACF and FCA. In the above, C, F, and A represent pure copper (C), ordinary iron (F), and pure aluminum (A), respectively. From left to right, the materials used are core F1 for the first layer, core F2 for the second layer, and core F3 for the third layer.

[0105] The hardness of each material is shown in Table 1. Hardness was measured using a Vickers hardness test. Specifically, the test load was 0.1 kgf for iron and 0.02 kgf for aluminum and copper. Hardness was measured at three points in the center of the core material cross section, and the average value was calculated.

[0106] [Table 1]

[0107] Using the hardness values ​​in Table 1, we confirmed the average hardness of the core material constituting the outermost layer (third layer) and the average hardness of the core material constituting the inner layers (first and second layers) for the ACF and FCA core material arrangements. The results are shown in Table 2.

[0108] [Table 2]

[0109] Next, the pipe material (copper pipe) with the core material disposed (inserted) therein was passed through a drawing die with the die diameters shown in Tables 3 and 4 to adjust the porosity inside the copper pipe by pre-processing. Note that pre-processing was not performed in Comparative Examples 1, 3, 5, and 9. The porosity was calculated by measuring the area inside the copper pipe and the area of ​​the core material from cross-sectional images of the copper pipe using the image processing software ImageJ. Figure 3 shows cross-sectional images of copper pipes with a core material disposed therein to form ACF or FCA before and after pre-processing. Specifically, Figure 3 shows a cross-sectional image of the copper pipe before pre-processing, where the outer diameter of the copper pipe was 11.0 mm, and cross-sectional images of the copper pipe after pre-processing, where the outer diameter of the copper pipe was reduced to 10.5 mm, 10.1 mm, and 9.85 mm by pre-processing.

[0110] Next, the pre-processed samples (in Comparative Examples 1, 3, 5, and 9, samples in which a core material was placed in a tubular material) were cut to a length of 500 mm, and one pass of drawing was performed under the drawing conditions (die diameter, area reduction rate) shown in Tables 3 and 4, to obtain the composite materials of Examples 1 to 5 and Comparative Examples 1 to 11.

[0111] [Table 3]

[0112] [Table 4]

[0113] (Filling rate) For the composite materials of Examples 1 to 5 and Comparative Examples 1 to 11 obtained as described above, the area inside the copper tube and the area of ​​the voids in the core material were measured from cross-sectional images of the copper tubes using image processing software ImageJ, and the filling rate was calculated as (1 - internal area / void area) x 100. The results are shown in Tables 5 and 6.

[0114] (Measurement of edge misalignment) When a core material is inserted into a pipe material and then drawn, the elongation varies depending on the material and arrangement of the core material, which can cause misalignment at the end of the pipe after drawing. Specifically, as shown in Figure 4, the length of the core material can become shorter than the length of the copper pipe (pipe material) after drawing.

[0115] For the composite materials of Examples 1 to 5 and Comparative Examples 1 to 11 obtained as described above, a thin wire was inserted into the end of the copper tube, and the absolute value of the difference (deviation) between the length of each core material and the length of the tube material was measured. However, in this example, since the length of the shortest core material among multiple core materials is focused on, if the length of the core material after drawing was longer than the length of the copper tube, the deviation was recorded as 0 mm. Furthermore, for Comparative Example 3, the deviation was not measured because it broke during the drawing process.

[0116] Next, the ratio (deviation rate) of the absolute value of the difference (deviation) between the length of each core material and the length of the tubing (after drawing) was calculated. Then, if the ratio (deviation rate) of the absolute value of the difference (deviation) between the length of each core material and the length of the tubing after drawing was 4.5% or less for any of the first to third layers, the tubing was deemed to have passed. In other words, if the ratio (deviation rate) of the absolute value of the difference (deviation) between the length of the shortest core material among the multiple core materials and the length of the tubing was 4.5% or less, the tubing was deemed to have passed. These results are shown in Tables 5 and 6.

[0117] Graphs showing the relationship between the arrangement of core materials, area reduction rate, void ratio, and displacement rate are shown in Figures 5 to 8. In Figures 5 to 8, the horizontal axis represents void ratio, and the vertical axis represents the calculated ratio (displacement rate) of the absolute value of the difference between the length of each core material and the length of the tube material after drawing. More specifically, Figure 5 shows the relationship between the void ratio and the displacement rate at the rear end when the arrangement of core materials is ACF and the area reduction rate is 20%. Figure 6 shows the relationship between the void ratio and the displacement rate at the rear end when the arrangement of core materials is ACF and the area reduction rate is 30%. Figure 7 shows the relationship between the void ratio and the displacement rate at the rear end when the arrangement of core materials is FCA and the area reduction rate is 20%. Figure 8 shows the relationship between the void ratio and the displacement rate at the rear end when the arrangement of core materials is FCA and the area reduction rate is 30%.

[0118] [Table 5]

[0119] [Table 6]

[0120] (Consideration) As can be seen from Table 5, when the core material was arranged as an ACF (the average hardness of the core material constituting the outermost layer was equal to or greater than the average hardness of the core material constituting the inner layer), Examples 1 to 4, which had wiredrawing conditions of a porosity of 15.5% or less and an area reduction rate of 20% or more, passed the test. As can be seen from Table 6, when the core material was arranged as an FCA (the average hardness of the core material constituting the outermost layer was lower than the average hardness of the core material constituting the inner layer), Example 5, which had wiredrawing conditions of a porosity of 8.5% or less and an area reduction rate of 30% or more, passed the test. The reason why the acceptable wiredrawing conditions differed depending on the core material arrangement is thought to be that when the core material was arranged in a combination of ACFs with a higher hardness iron wire on the outside, the processing was more easily transmitted to not only the outermost layer (third layer) but also the inner layers (first and second layers), resulting in more uniform processing.

[0121] [Examples 6 to 10, Comparative Examples 12 to 23] First, the pipe materials and core materials used in Examples 6 to 10 and Comparative Examples 12 to 23 will be explained below.

[0122] The tube material used was a phosphorus-deoxidized copper tube (C1220T-H) with an outer diameter of φ7, an inner diameter of φ5, and a length of 650 mm.

[0123] Two types of wire were used for the core material: pure aluminum wire (A1070-O) and ordinary iron wire (SWM-B (SWRM6)). Both wires had a diameter of φ1.5 and a length of 650 mm.

[0124] Seven core materials were arranged regularly inside the copper pipe, as shown in Figure 2. The central core material is referred to as the first layer (inner layer), and the six adjacent core materials are referred to as the second layer (outermost layer). Core materials of the same material are arranged within each layer, and there are two combinations of materials for the first layer core material F4 and the second layer core material F5: AF and FA. In the above, F and A represent ordinary iron (F) and pure aluminum (A), respectively, and from left to right, they represent the materials for the first layer core material F4 and the second layer core material F5.

[0125] Using the hardness values ​​in Table 1, the average hardness of the core material constituting the outermost layer (second layer) and the average hardness of the core material constituting the inner layer (first layer) were confirmed for the AF and FA core material arrangements. The results are shown in Table 7.

[0126] [Table 7]

[0127] Next, the pipe material (copper pipe) with the core material disposed (inserted) therein was passed through a drawing die with the die diameters shown in Tables 8 and 9 to adjust the porosity inside the copper pipe by pre-processing. Note that pre-processing was not performed in Comparative Examples 12, 14, 16, and 20. The porosity was calculated by measuring the area inside the copper pipe and the area of ​​the core material from cross-sectional images of the copper pipe using the image processing software ImageJ. Figure 9 shows cross-sectional images of copper pipes with a core material disposed therein to form AF or FA before and after pre-processing. Specifically, Figure 9 shows a cross-sectional image of the copper pipe before pre-processing, where the outer diameter of the copper pipe was 7.0 mm, and cross-sectional images of the copper pipe after pre-processing, where the outer diameter of the copper pipe was reduced to 6.53 mm, 6.30 mm, 6.15 mm, and 6.07 mm by pre-processing.

[0128] Next, the pre-processed samples (samples in which a core material was placed in a tubular material in Comparative Examples 12, 14, 16, and 20) were cut to a length of 500 mm. However, in Comparative Example 17, the sample was cut to a length of 460 mm as an exception, because the length of the sample was insufficient. The cut-to-length samples were subjected to one pass of drawing under the drawing conditions (die diameter, area reduction rate) shown in Tables 8 and 9, to obtain composite materials of Examples 6 to 10 and Comparative Examples 11 to 23.

[0129] [Table 8]

[0130] [Table 9]

[0131] (Filling rate) For the composite materials of Examples 6 to 10 and Comparative Examples 12 to 23 obtained as described above, the area inside the copper tube and the area of ​​the voids in the core material were measured from cross-sectional images of the copper tubes using the image processing software ImageJ, and the filling rate was calculated as (1 - internal area / void area) x 100. The results are shown in Tables 10 and 11.

[0132] (Measurement of edge misalignment) When a core material is inserted into a pipe material and then drawn, the elongation varies depending on the material and arrangement of the core material, which can cause misalignment at the end of the pipe after drawing. Specifically, as shown in Figure 10, the length of the core material can become shorter than the length of the copper pipe (pipe material) after drawing.

[0133] For the composite materials of Examples 6 to 10 and Comparative Examples 12 to 23 obtained as described above, a thin wire was inserted into the end of the copper tube, and the absolute value of the difference (deviation) between the length of each core material and the length of the tube material was measured. However, since this example focuses on the length of the shortest core material among multiple core materials, if the length of the core material after drawing was longer than the length of the copper tube, the deviation was set to 0 mm.

[0134] Next, the ratio (deviation rate) of the absolute value of the difference (deviation) between the length of each core material and the length of the tubing (after drawing) was calculated. Then, if the ratio (deviation rate) of the absolute value of the difference (deviation rate) between the length of each core material and the length of the tubing after drawing was 4.5% or less in both the first and second layers, the tubing was deemed to have passed. In other words, if the ratio (deviation rate) of the absolute value of the difference (deviation rate) between the length of the shortest core material among the multiple core materials and the length of the tubing was 4.5% or less, the tubing was deemed to have passed. These results are shown in Tables 10 and 11.

[0135] 11 to 14 show graphs illustrating the relationship between the arrangement of core materials, the area reduction rate, the void ratio, and the rear end displacement rate. Specifically, in FIGS. 11 to 14, the horizontal axis represents the void ratio (%), and the vertical axis represents the calculated ratio (displacement rate) of the absolute value of the difference between the length of each core material and the length of the tube material after drawing. FIG. 11 shows the relationship between the void ratio and the rear end displacement rate when the arrangement of core materials is AF and the area reduction rate is 20%. FIG. 12 shows the relationship between the void ratio and the rear end displacement rate when the arrangement of core materials is AF and the area reduction rate is 30%. FIG. 13 shows the relationship between the void ratio and the rear end displacement rate when the arrangement of core materials is FA and the area reduction rate is 20%. FIG. 14 shows the relationship between the void ratio and the rear end displacement rate when the arrangement of core materials is FA and the area reduction rate is 30%.

[0136] [Table 10]

[0137] [Table 11]

[0138] (Consideration) As can be seen from Table 10, when the core material was arranged in an AF configuration (the average hardness of the core material constituting the outermost layer was equal to or greater than the average hardness of the core material constituting the inner layer), Examples 6 to 9, which had wiredrawing conditions of a porosity of 15.5% or less and an area reduction rate of 20% or more, passed the test. As can be seen from Table 11, when the core material was arranged in an FA configuration (the average hardness of the core material constituting the outermost layer was lower than the average hardness of the core material constituting the inner layer), Example 10, which had wiredrawing conditions of a porosity of 8.5% or less and an area reduction rate of 30% or more, passed the test. The reason why the acceptable wiredrawing conditions differed depending on the core material arrangement is thought to be that when the core material was arranged in an AF configuration, with the iron wire with higher hardness on the outside, the processing was more easily transmitted to not only the outermost layer (second layer) but also the inner layer (first layer), resulting in more uniform processing.

[0139] From the above, Test Example 1, it was found that when the multiple core materials have a multilayer structure of two or more layers in the cross section of the tubular material, the multilayer structure has at least one inner layer composed of at least one core material and an outermost layer composed of two or more core materials, and the average hardness of the core material constituting the outermost layer is equal to or higher than the average hardness of the core material constituting the inner layer, the composite materials of Examples 1 to 4 and Examples 6 to 9, which were manufactured with a void ratio within the tubular material before wiredrawing of 15.5% or less and an area reduction rate during wiredrawing of 20% or more, have small displacement at the ends and do not suffer from uneven deformation due to wiredrawing. Furthermore, when the multiple core materials have a multi-layer structure of two or more layers in the cross-section of the tubular material, the multi-layer structure has at least one inner layer composed of at least one core material and an outermost layer composed of two or more core materials, and the average hardness of the core material constituting the outermost layer is less than the average hardness of the core material constituting the inner layer, it was found that the composite materials of Examples 5 and 10, which were manufactured with a void ratio within the tubular material before wiredrawing of 8.5% or less and an area reduction rate during wiredrawing of 30% or more, had small misalignment at the ends and did not suffer from uneven deformation due to wiredrawing.

[0140] <Test Example 2> Composite materials were manufactured using three types of core constituent materials: aluminum (Al), copper (Cu), and iron (Fe). The predicted values ​​based on the prediction method described above were compared with the actual measured values ​​of the manufactured composite material for the four properties of density, tensile strength, Young's modulus, and electrical resistivity to evaluate whether a composite material (multi-property material) with the predicted properties could be manufactured using the wire drawing manufacturing method.

[0141] Furthermore, Al, Cu, and Fe were used as the core material, taking into consideration the cost, as they are suitable materials for composite materials that require lightness (low density), high tensile strength, and low electrical resistivity (high electrical conductivity).

[0142] [Measurement of actual values] (Experimental Method) A pure copper tube (C1020-H) with an outer diameter of φ11, an inner diameter of φ8, and a length of 800 mm was prepared as the tube material.

[0143] Three types of wire were used for the core material: (a) pure copper wire (C1020W-O), (b) pure aluminum wire (A1070-O), and (c) ordinary iron wire (SWM-B (SWRM6)). All of them had a diameter of φ1.5 and a length of 800 mm.

[0144] Nineteen core materials were arranged regularly inside the copper pipe as shown in Figure 1. Specifically, one core material F1 of the first layer (inner layer) was arranged in the center of the pipe material, six core materials F2 of the second layer (inner layer) were arranged around the core material of the first layer, and 12 core materials F3 of the third layer (outermost layer) were arranged around the core material of the second layer.

[0145] Within each layer, core materials of the same material are arranged, and the six combinations of materials for the first layer core material F1, the second layer core material F2, and the third layer core material F3 are AFC, ACF, FAC, FCA, CAF, and CFA. In the above, C, F, and A represent pure copper (C), pure iron (F), and pure aluminum (A), respectively, and from left to right, represent the materials for the first layer core material F1, the second layer core material F2, and the third layer core material F3. For example, FCA means that the first layer is made of iron (F), the second layer is made of copper (C), and the third layer is made of aluminum (A).

[0146] According to the combination of core materials, each core material was inserted into the above-mentioned tube material, and a four-pass drawing process was performed using a drawing die with a half angle of 6° to obtain a drawn material (composite material). The die schedule is shown in Table 12.

[0147] [Table 12]

[0148] The area reduction rate for the first pass in Table 12 was calculated using the net cross-sectional area of ​​the core material and pipe material and the φ9 die diameter as shown in the following formula (1). The area reduction rate for the second pass and thereafter is a value calculated only from the die diameter.

[0149]

number

[0150] As a reference value, the material combinations of the first layer core material F1, the second layer core material F2, and the third layer core material F3 were CCC, FFF, and AAA, and a four-pass drawing process was performed using the same method as the manufacturing method for the composite materials obtained according to the above six combinations (AFC, ACF, FAC, FCA, CAF, CFA) to obtain drawn materials (single core materials).

[0151] (Measurement results of characteristics) The density, tensile strength, Young's modulus, and electrical resistance of the drawn materials obtained by four-pass drawing were measured using the following methods. The measurement results are shown in Table 13.

[0152] ·density A 50 mm test piece was cut out at an arbitrary position from the drawn material and measured using the Archimedes method.

[0153] Tensile strength A 300 mm test piece was cut out from the drawn material and subjected to a tensile test in the axial direction until it broke, and the load at break was measured.

[0154] Young's modulus The pultruded materials were subjected to tensile tests using an autograph with a chuck distance of 200 mm and a strain rate of 0.00025 / sec. The stress-strain curve was obtained using the elongated diameter, and the Young's modulus was calculated from the slope of the elastic region. Due to sample size limitations, only pultruded materials with core material combinations of ACF, CFA, FFF, AAA, and CCC were measured.

[0155] Electrical resistance value Voltage terminals were attached to the drawn material and the electrical resistivity was measured by the four-terminal method. The distance between the terminals was 150 mm.

[0156] [Table 13]

[0157] ·Cross-sectional area ratio A cross-sectional view of the pultruded material is shown in Figure 15. It was confirmed that all of the pultruded materials had a dense cross section with few voids. The cross-sectional area ratio of each pultruded material was measured from the cross-sectional image shown in Figure 15 using the image processing software ImageJ. The measurement results of the cross-sectional area ratio (%) of each pultruded material are shown in Table 14.

[0158] [Table 14]

[0159] [Characteristics prediction] Next, as shown below, the four characteristic values ​​of each raw material (Al, Fe, Cu, Cu pipe) estimated from a single core material or the four characteristic values ​​of each raw material actually measured were used to predict the four characteristics of the drawn material according to the above-mentioned composite rule.

[0160] -Characteristic values ​​of each raw material estimated from a single core material The density, tensile strength, Young's modulus, and electrical resistivity of copper were calculated from the measured values ​​of the density, tensile strength, Young's modulus, and electrical resistivity of the drawn material (single core material) after four-pass drawing when both the core material and the tube material were copper (CCC). It was assumed that the properties of the core material and the tube material were equivalent. Next, the density, tensile strength, Young's modulus, and electrical resistivity of the drawn material (single core material) after four-pass drawing when copper was used as the tube material and only iron (FFF) or only aluminum (AAA) was used as the core material were measured. The density, tensile strength, Young's modulus, and electrical resistivity of iron and aluminum were calculated by back-calculation from the measured values ​​of the density, tensile strength, Young's modulus, and electrical resistivity of the drawn material (single core material) after four-pass drawing and the measured cross-sectional area ratio. The results are shown in Table 15.

[0161] · Characteristic values ​​of each raw material (actual measured values) The density, tensile strength, Young's modulus, and electrical resistance of the pipe material and the core material of each material were measured using the same method as described in the above-mentioned [Measurement of Actual Values] (Measurement Results of Properties). The results are shown in Table 15.

[0162] [Table 15]

[0163] Using the property values ​​in Table 15, the property values ​​of each drawn material were calculated according to the above-mentioned rule of mixtures, and property predictions were made. Note that the area ratio used to calculate the property values ​​of each drawn material was the cross-sectional area ratio in Table 14, which was measured from the cross-sectional image shown in Fig. 15. The predicted property values ​​of each drawn material obtained by calculation are shown in Table 16.

[0164] [Table 16]

[0165] [Comparison of predicted and measured values] The results of comparing the predicted values ​​(calculated using the characteristic values ​​of each raw material estimated from a single core material, and calculated using the characteristic values ​​(actually measured values) of each raw material) with the measured values ​​for the four characteristic values ​​of the composite material are shown in Figures 16 to 19. In Figures 16 to 19, the horizontal axis represents the calculated values ​​(predicted values), and the vertical axis represents the actually measured values.

[0166] Figure 16 shows that the predicted and measured density values ​​are nearly identical, indicating that the resulting drawn material possesses the predicted properties. Figure 17 shows that the measured tensile strength values ​​tended to be higher than the predicted values ​​calculated from the characteristic values ​​of each raw material, which is thought to be due to the effect of work hardening. Figure 19 shows that the measured electrical resistivity values ​​tended to be higher than the predicted values ​​when iron wire was used in the outermost layer, which is thought to be because the contribution of conductivity from the materials used in the first and second layers was reduced by being shielded by the iron.

[0167] 16 to 19, the correlation coefficients between the predicted values ​​and the measured values ​​are shown in Table 17. From these results, it was confirmed that the four properties of each composite material produced, namely density, tensile strength, Young's modulus, and electrical resistivity, were almost in line with the predicted values.

[0168] [Table 17]

[0169] From the above, it is possible to predict the properties of the composite material and narrow down the configuration of the tube material and core material at the design stage, and then apply wire drawing to the composite material to obtain a long product. [Explanation of symbols]

[0170] F1 First layer core material F2 2nd layer core material F3 Third layer (outermost layer) core material F4 1st layer core material F5 2nd layer (outermost layer) core material P Composite material S pipe material d f Core diameter d i Inner diameter of the pipe d0 pipe outer diameter

Claims

1. A long composite material that has been wiredrawn and includes a plurality of core materials and a cylindrical tubular material that covers the outer peripheral surfaces of the plurality of core materials, At least one of the plurality of core materials is made of a material different from the other core materials, The filling rate of the plurality of core materials in the cross section of the pipe material is 97.5% or more, A long composite material in which the ratio of the absolute value of the difference between the length of the shortest core material among the plurality of core materials and the length of the tube material to the length of the tube material is 4.5% or less.

2. The long composite material according to claim 1 , wherein the filling rate is 99.0% or more.

3. A method for manufacturing a long composite material, comprising inserting a plurality of core materials into a cylindrical tubular material and performing wire drawing, At least one of the plurality of core materials is made of a material different from the other core materials, the plurality of core materials have a multi-layer structure of two or more layers in a cross section of the pipe material, The multilayer structure has at least one inner layer composed of at least one core material and an outermost layer composed of two or more core materials, the average hardness of the core material constituting the outermost layer is equal to or greater than the average hardness of the core material constituting the inner layer; The void ratio within the tube material before the wiredrawing process is 15.5% or less, A method for producing a long composite material, wherein the area reduction rate in the wire drawing process is 20% or more.

4. A method for manufacturing a long composite material, comprising inserting a plurality of core materials into a cylindrical tubular material and performing wire drawing, At least one of the plurality of core materials is made of a material different from the other core materials, the plurality of core materials have a multi-layer structure of two or more layers in a cross section of the pipe material, The multilayer structure has at least one inner layer composed of at least one core material and an outermost layer composed of two or more core materials, the average hardness of the core material constituting the outermost layer is lower than the average hardness of the core material constituting the inner layer, The void ratio within the tube material before the wiredrawing process is 8.5% or less, A method for producing a long composite material, wherein the area reduction rate in the wire drawing process is 30% or more.

5. A method for producing a long composite material as described in claim 3 or 4, in which the combination of the tubular material and the multiple core materials is adjusted, the multiple core materials are inserted into the tubular material, and then a wire drawing process is performed to produce a long composite material having desired properties.

6. A method for manufacturing a long composite material as described in claim 5, wherein the combination of the tube material and the multiple core materials is a combination of the material constituting the tube material, the number of the multiple core materials, the material constituting each of the multiple core materials, and the insertion position of each of the multiple core materials into the tube material.

7. 5. The method for producing a long composite material according to claim 3, wherein the plurality of core materials are inserted at positions symmetrical to each other along an axis.

8. The method for producing a long composite material according to claim 3 or 4, wherein the number of the plurality of core materials is equal to or greater than the number of desired properties of the composite material.

9. The method for producing a long composite material according to claim 3 or 4, wherein the cross-sectional shape of the core material is circular or polygonal.

10. The method for producing a long composite material according to claim 3 or 4, wherein the core material is a wire material.

11. The method for producing a long composite material according to claim 3 or 4, wherein the deformation resistance of the tubular material is greater than the deformation resistance of at least one of the plurality of core materials.

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