Copper alloy wire, copper alloy stranded wire, coated wire, and wire with terminals

Abstract

A copper alloy wire having a composition made of a copper alloy containing 0.05% by mass or more and 1.60% by mass or less of iron, 0.01% by mass or more and 0.70% by mass or less of phosphorus, and 0.05% by mass or more and 0.70% by mass or less of tin, a wire diameter of 0.1 mm or more and 15.0 mm or less, and a cross section having a central portion and an outer peripheral portion, wherein the component ratio of the tin content rate in the central portion to the tin content rate in the outer peripheral portion is 2.0 or less.

Description

[Technical Field]

[0001] The present disclosure relates to a copper alloy wire, a copper alloy stranded wire, a coated electric wire, and an electric wire with a terminal. [Background technology]

[0002] Patent Document 1 discloses a copper alloy wire made of a copper alloy containing a specific additive element at a predetermined content. The specific additive element is at least one selected from the group consisting of iron (Fe), titanium (Ti), tin (Sn), silver (Ag), magnesium (Mg), zinc (Zn), chromium (Cr), and phosphorus (P). This copper alloy wire is produced by drawing a cast wire produced by continuous casting. Hereinafter, the copper alloy wire will be simply referred to as a copper alloy wire. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-203136 Summary of the Invention

[0004] The copper alloy wire of the present disclosure has a composition made of a copper alloy containing 0.05% by mass to 1.60% by mass of iron, 0.01% by mass to 0.70% by mass of phosphorus, and 0.05% by mass to 0.70% by mass of tin, a wire diameter of 0.1 mm to 15.0 mm, and a cross section having a central portion and an outer peripheral portion, wherein the ratio of the tin content in the central portion to the tin content in the outer peripheral portion is 2.0 or less. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a schematic view showing an example of a copper alloy wire according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Figure 3]FIG. 3 is a schematic view illustrating the cast texture angle of the cast wire rod in the manufacturing process of the copper alloy wire according to the embodiment. [Figure 4] FIG. 4 is a schematic perspective view showing a coated electric wire according to an embodiment. [Figure 5] FIG. 5 is a schematic side view showing the vicinity of the terminal portion of the electric wire with terminal according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0006] [Problem to be solved by this disclosure] A cast wire made of a copper alloy may have a structure in which an additive element is segregated at grain boundaries or a structure in which a compound containing the additive element is unevenly distributed. When a cast wire having such a structure is subjected to wire drawing, breakage due to the structure easily occurs. A copper alloy wire obtained by wire drawing a cast wire that is prone to breakage tends to have poor mechanical properties.

[0007] An object of the present disclosure is to provide a copper alloy wire having excellent mechanical properties.

[0008] [Effects of this disclosure] The copper alloy wire of the present disclosure has excellent mechanical properties.

[0009] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] (1) A copper alloy wire according to an embodiment of the present disclosure has a composition made of a copper alloy containing 0.05% by mass to 1.60% by mass of iron, 0.01% by mass to 0.70% by mass of phosphorus, and 0.05% by mass to 0.70% by mass of tin, a wire diameter of 0.1 mm to 15.0 mm, and a cross section having a center and an outer periphery, wherein the ratio of the tin content in the center to the tin content in the outer periphery is 2.0 or less.

[0011] Copper alloy wires made of copper alloys containing iron, phosphorus, and tin as additive elements in the above ranges have excellent tensile strength. In particular, copper alloy wires in which the tin content of the additive elements is 2.0 or less have excellent mechanical properties throughout their entire length because the center is not embrittled. Copper alloy wires in which the tin content of the additive elements is 2.0 or less are less likely to break during the manufacturing process and have excellent productivity. Copper alloy wires in which the tin content of the additive elements is 2.0 or less are manufactured by drawing a cast wire rod in which the tin content is 2.0 or less. When the tin content exceeds 2.0, tin is concentrated in the center of the cast wire rod, and the tin-concentrated area is prone to embrittlement. Therefore, when a cast wire rod in which the tin content exceeds 2.0 is drawn, breakage is likely to occur starting from the tin-concentrated area. In other words, a cast wire having a tin content of 2.0 or less is resistant to breakage, and a copper alloy wire obtained by drawing this resistant cast wire is excellent in productivity and mechanical properties.

[0012] (2) In the copper alloy wire of (1) above, the central portion may be a circle having a center on the central axis of the copper alloy wire and a radius of 1 / 8 of the wire diameter, and the outer circumferential portion may be a ring-shaped portion having a predetermined length of 1 / 8 of the wire diameter from the outer circumferential surface of the copper alloy wire toward the central axis.

[0013] A copper alloy wire in which the tin content in a relatively narrow central region is 2.0 or less tends to have high mechanical properties over the entire length of the copper alloy wire.

[0014] (3) In the copper alloy wire of (1) or (2), the ratio of the phosphorus content in the central portion to the phosphorus content in the outer periphery may be 2.0 or less.

[0015] A copper alloy wire having a phosphorus content of 2.0 or less in addition to a tin content is less likely to become embrittled at the center, and tends to have high mechanical properties over the entire length of the copper alloy wire.

[0016] (4) In the copper alloy wire according to any one of (1) to (3), the outer circumferential surface of the copper alloy wire may have processing marks.

[0017] The formation of processing marks on the outer peripheral surface of a copper alloy wire indicates that the copper alloy wire is obtained by subjecting a cast wire material to processing corresponding to the processing marks. The processing marks are, for example, wiredrawing marks. As described above, a copper alloy wire having a tin content of 2.0 or less is manufactured by subjecting a cast wire material having a tin content of 2.0 or less to wiredrawing. A copper alloy wire obtained by subjecting a cast wire material having a tin content of 2.0 or less to wiredrawing is excellent in productivity and mechanical properties.

[0018] (5) In the copper alloy wire according to any one of (1) to (4), the tensile strength may be 250 MPa or more.

[0019] A copper alloy wire having a tensile strength of 250 MPa or more has excellent strength.

[0020] (6) A copper alloy stranded wire according to an embodiment of the present disclosure is formed by twisting together a plurality of copper alloy wires according to any one of (1) to (5) above.

[0021] A stranded wire has superior flexibility compared to a single wire having the same cross-sectional area, and each strand is less likely to break even when subjected to impact and repeated bending. Therefore, the copper alloy stranded wire has excellent impact resistance and fatigue properties.

[0022] (7) A coated electric wire according to an embodiment of the present disclosure includes a conductor and an insulating layer covering the outer periphery of the conductor, and the conductor includes the copper alloy stranded wire described above in (6).

[0023] The coated electric wire has excellent impact resistance and fatigue characteristics because it includes a conductor made of a copper alloy twisted wire, which has excellent impact resistance and fatigue characteristics.

[0024] (8) An electric wire with a terminal according to an embodiment of the present disclosure includes the insulated electric wire of (7) above and a terminal portion attached to an end of the insulated electric wire.

[0025] The electric wire with terminal has excellent impact resistance and fatigue characteristics because it includes, as a constituent element, a covered electric wire having excellent impact resistance and fatigue characteristics.

[0026] [Details of the embodiments of the present disclosure] Specific examples of the copper alloy wire, copper alloy stranded wire, coated electric wire, and electric wire with terminal of the present disclosure will be described with reference to the drawings. The same reference numerals in the drawings indicate the same or equivalent parts. In each drawing, for the sake of convenience, some of the configurations may be exaggerated or simplified. The dimensional ratios of each part in the drawings may also differ from the actual ratios. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0027] <Copper alloy wire> Overview The copper alloy wire 1 of the embodiment has a composition made of a copper alloy containing a specific additive element at a predetermined content ratio, a wire diameter 1d shown in FIG. 1, and a cross section 2 shown in FIG. 2. The cross section 2 has a central portion 3 and an outer peripheral portion 4. One of the features of the copper alloy wire 1 of the embodiment is that the component ratio of tin among the additive elements is 2.0 or less. The component ratio of tin is the content ratio of tin in the central portion 3 relative to the content ratio of tin in the outer peripheral portion 4. The copper alloy wire 1 is manufactured by drawing a cast wire rod.

[0028] ≪Composition≫ The composition of the copper alloy wire 1 is a copper alloy containing additive elements, with the remainder being copper (Cu) and unavoidable impurities. The copper alloy is an alloy containing copper in the largest amount. The additive elements include iron (Fe), phosphorus (P), and tin (Sn) as essential additive elements. The iron content is 0.05% by mass or more and 1.60% by mass or less. The phosphorus content is 0.01% by mass or more and 0.70% by mass or less. The tin content is 0.05% by mass or more and 0.70% by mass or less. The copper alloy wire 1 made of a copper alloy containing iron, phosphorus, and tin as additive elements in the above ranges has excellent tensile strength. The content ratio of each element in the composition is the mass ratio of each element when the copper alloy composition is 100% by mass.

[0029] The iron content may be 0.10% by mass or more and 1.50% by mass or less, or 0.20% by mass or more and 1.40% by mass or less, the phosphorus content may be 0.03% by mass or more and 0.60% by mass or less, or 0.05% by mass or more and 0.50% by mass or less, and the tin content may be 0.07% by mass or more and 0.60% by mass or less, or 0.10% by mass or more and 0.50% by mass or less.

[0030] The composition of the copper alloy wire 1 may or may not contain additional elements other than iron, phosphorus, and tin. The optional additional elements other than iron, phosphorus, and tin are, for example, silver (Ag), magnesium (Mg), nickel (Ni), and silicon (Si). The optional additional elements other than iron, phosphorus, and tin may be one type or two or more types. In other words, the composition of the copper alloy wire 1 may include the essential additional elements and at least one element of the optional additional elements, with the balance being unavoidable impurities and copper.

[0031] The total content of the additional elements, including both the essential and optional additional elements, is, for example, 0.11 mass % or more and 3.10 mass % or less, 0.12 mass % or more and 3.00 mass % or less, or 0.13 mass % or more and 2.90 mass % or less.

[0032] <Wire diameter> The wire diameter 1d of the copper alloy wire 1 is 0.1 mm or more and 15.0 mm or less. If the wire diameter 1d is 0.1 mm or more, the degree of wiredrawing can be increased in the manufacturing process of the copper alloy wire 1. If the degree of wiredrawing is large, the strength of the copper alloy wire 1 manufactured by work hardening tends to be increased. If the wire diameter 1d is 15.0 mm or less, the casting speed can be increased in the manufacturing process of the copper alloy wire 1. If the casting speed is high, the copper alloy wire 1 can be manufactured with high productivity. The casting speed will be described later. The wire diameter 1d of the copper alloy wire 1 may be 0.11 mm or more and 14.0 mm or less, or 0.12 mm or more and 13.0 mm or less. The wire diameter 1d of the copper alloy wire 1 may be 0.1 mm or more and 3.0 mm or less, or 0.1 mm or more and 2.5 mm or less.

[0033] The shape of the cross section 2 of the copper alloy wire 1 is not particularly limited. The cross section 2 is a cross section perpendicular to the longitudinal direction of the copper alloy wire 1. The shape of the cross section 2 in this example is circular as shown in FIG. 2. The copper alloy wire 1 in this example is a round wire as shown in FIG. 1. The shape of the cross section 2 may be elliptical or polygonal. The polygonal shape is, for example, a square or hexagonal shape. When the copper alloy wire 1 is a round wire, the shape of the cross section 2 is circular, and the wire diameter 1d of the copper alloy wire 1 is the diameter. When the shape of the cross section 2 is elliptical or polygonal, the wire diameter 1d is the diameter of a circle having an area equal to the area of ​​the cross section 2.

[0034] <<Center and Periphery>> As shown in FIG. 2, the cross section 2 has a central portion 3 and an outer peripheral portion 4. The central portion 3 is the interior of a circle centered on the central axis of the copper alloy wire 1 and having a radius 3r that is 1 / 8 of the wire diameter 1d. The outer peripheral portion 4 is a ring-shaped interior extending from the outer peripheral surface 5 of the copper alloy wire 1 toward the central axis and having a predetermined length 3L that is 1 / 8 of the wire diameter 1d. Between the central portion 3 and the outer peripheral portion 4 is an intermediate portion 6. The intermediate portion 6 is the ring-shaped interior between the outer peripheral surface of the central portion 3 and the inner peripheral surface of the outer peripheral portion 4. In FIG. 2, for ease of understanding, the boundary between the central portion 3 and the intermediate portion 6 and the boundary between the outer peripheral portion 4 and the intermediate portion 6 are indicated by two-dot chain lines.

[0035] The ratio B / A of the tin content B in the central portion 3 to the tin content A in the outer circumferential portion 4 is 2.0 or less. Hereinafter, the ratio of the tin content B in the central portion 3 to the tin content A in the outer circumferential portion 4 will be simply referred to as the tin content ratio. A copper alloy wire 1 having a tin content ratio of 2.0 or less has excellent mechanical properties throughout its entire length because the central portion 3 is not embrittled. As shown in the test examples described below, a copper alloy wire 1 having a tin content ratio of 2.0 or less is manufactured without breakage during the manufacturing process. A copper alloy wire 1 having a tin content ratio of 2.0 or less is manufactured by drawing a cast wire having a tin content ratio of 2.0 or less. When the tin content ratio exceeds 2.0, tin is concentrated in the central portion of the cast wire, and the tin-concentrated portion is embrittled. When a cast wire having a tin content ratio of more than 2.0 is drawn, breakage is likely to occur starting from the tin-concentrated portion. In other words, the copper alloy wire 1 having a tin content of 2.0 or less can be obtained by drawing a cast wire having a tin content of 2.0 or less without wire breakage. The tin content may be 1.9 or less, or 1.8 or less.

[0036] The component ratio C / A, which is the tin content ratio C in the intermediate portion 6 to the tin content ratio A in the outer circumferential portion 4, is, for example, 2.0 or less, 1.9 or less, or 1.8 or less. The component ratio B / C, which is the tin content ratio B in the central portion 3 to the tin content ratio C in the intermediate portion 6, is, for example, 2.0 or less, 1.9 or less, or 1.8 or less. The copper alloy wire 1 in which the values ​​obtained for the ratios B / A, C / A, and B / C are each 2.0 or less has few tin-enriched portions throughout the entire cross section 2.

[0037] The ratio β / α of the phosphorus content β in the central portion 3 to the phosphorus content α in the outer peripheral portion 4 is, for example, 2.0 or less. Hereinafter, the ratio of the phosphorus content β in the central portion 3 to the phosphorus content α in the outer peripheral portion 4 will be simply referred to as the phosphorus content ratio. A copper alloy wire 1 having a phosphorus content ratio of 2.0 or less in addition to a tin content ratio is less likely to embrittle the central portion 3 and more likely to have high mechanical properties throughout the entire length of the copper alloy wire 1. In a cast wire rod, when the phosphorus content ratio is 2.0 or less, wire breakage is less likely to occur even when wiredrawing is performed. The phosphorus content ratio may be 1.9 or less, or 1.8 or less.

[0038] The component ratio γ / α of the phosphorus content ratio γ in the intermediate portion 6 to the phosphorus content ratio α in the outer circumferential portion 4 is, for example, 2.0 or less, 1.9 or less, or 1.8 or less. Moreover, the component ratio β / γ of the phosphorus content ratio β in the central portion 3 to the phosphorus content ratio γ in the intermediate portion 6 is, for example, 2.0 or less, 1.9 or less, or 1.8 or less. The copper alloy wire 1 having each of the values ​​obtained for the ratios β / α, γ / α, and β / γ of 2.0 or less has few locations where phosphorus is concentrated throughout the entire cross section 2.

[0039] The component ratio b / a, which is the iron content b in the central portion 3 to the iron content a in the outer circumferential portion 4, is, for example, 2.0 or less, 1.9 or less, or 1.8 or less. The component ratio c / a, which is the iron content c in the intermediate portion 6 to the iron content a in the outer circumferential portion 4, is, for example, 2.0 or less, 1.9 or less, or 1.8 or less. The component ratio b / c, which is the iron content b in the central portion 3 to the iron content c in the intermediate portion 6, is, for example, 2.0 or less, 1.9 or less, or 1.8 or less. The copper alloy wire 1 of this example, in which the values ​​obtained for the ratios b / a, c / a, and b / c are each 2.0 or less, has few iron-enriched portions throughout the entire cross section 2. The copper alloy wire 1 of this example has few iron-enriched portions throughout the entire cross section 2.

[0040] The components and content ratios of each element in the central portion 3, the outer peripheral portion 4, and the intermediate portion 6 can be measured by mapping analysis using an electron probe microanalyzer (EPMA).

[0041] The outer peripheral surface 5 of the copper alloy wire 1 has, for example, processing marks (not shown). The formation of processing marks on the outer peripheral surface 5 of the copper alloy wire 1 indicates that the copper alloy wire 1 is obtained by subjecting a cast wire material to processing corresponding to the processing marks. The processing marks are, for example, wiredrawing marks. The wiredrawing marks are formed in the form of stripes extending along the length of the copper alloy wire 1. The copper alloy wire 1 is produced by subjecting a cast wire material to wiredrawing. The copper alloy wire 1 may also be produced by subjecting a cast wire material to rolling processing and then subjecting the resulting wire material to wiredrawing.

[0042] <Tensile strength> The tensile strength of the copper alloy wire 1 is, for example, 250 MPa or more. A copper alloy wire 1 having a tensile strength of 250 MPa or more has excellent strength. The tensile strength can be measured based on JIS Z 2241:2011. The tensile strength may be 260 MPa or more, or 270 MPa or more. In terms of the balance with electrical conductivity, the tensile strength may be 1200 MPa or less.

[0043] <Stretch> The copper alloy wire 1 having a tin content of 2.0 or less has an elongation that is 10% or more higher than that of the copper alloy wire 1 having a tin content of more than 2.0, for example.

[0044] <Method of manufacturing copper alloy wire> The above-mentioned copper alloy wire 1 can be manufactured through a casting process of producing a cast wire made of a copper alloy and a wiredrawing process of drawing the cast wire. Fig. 3 shows an example of a cast wire 10.

[0045] <Casting process> In the casting process, a molten copper alloy is subjected to intermittent continuous casting to produce a cast wire 10. The copper alloy has the same composition as the copper alloy wire 1 described above. Continuous casting is, for example, top casting, vertical casting, or horizontal casting. In top casting, the end of a cylindrical mold is placed in the molten metal, and the wire solidified inside the mold is pulled up above the mold to produce the cast wire 10. In intermittent continuous casting, the cast wire 10 is repeatedly pulled and stopped.

[0046] The ratio S1 / ST of the time S1 (sec) of one withdrawal to the total time ST (sec) of the time S1 (sec) of one withdrawal and the time S2 (sec) of one stop is, for example, 0.75 or less. The wire diameter x (mm) of the cast wire 10 and the casting speed y (mm / sec) of the cast wire 10 satisfy, for example, y≦155 / x. The casting speed y is the value obtained by dividing the length of one cast wire 10 by the time required to produce one cast wire 10. In other words, the casting speed y is the value obtained by dividing the length of the cast wire 10 by the total time of all withdrawals S1 and all stop times S2. By making the ratio S1 / ST 0.75 or less and satisfying y≦155 / x, it is easy to produce a cast wire 10 having a cast texture angle of 70° or less, as described below. A cast wire 10 having a cast texture angle of 70° or less is likely to have a tin content ratio of 2.0 or less.

[0047] The ratio S1 / ST may be 0.70 or less, or 0.65 or less. There is no particular lower limit for the ratio S1 / ST. The ratio S1 / ST may be 0.10 or more, 0.15 or more, or 0.20 or more. That is, the ratio S1 / ST may be 0.10 or more and 0.75 or less, 0.15 or more and 0.70 or less, or 0.20 or more and 0.65 or less. The wire diameter x is, for example, 5 mm or more and 25 mm or less. The wire diameter x may be 6 mm or more and 24 mm or less, or 7 mm or more and 23 mm or less. The casting speed y is, for example, 1.67 mm / sec or more and 30 mm / sec or less. The casting speed y may be 2 mm / sec or more and 28 mm / sec or less, or 2.5 mm / sec or more and 25 mm / sec or less.

[0048] The acceleration from the stopped state of the cast wire 10 to the withdrawal speed is, for example, 50 mm / sec. 2 More than 1500mm / sec 2 The drawing speed is the value obtained by dividing the length of the cast wire 10 by the total time S1 of all the drawing operations. 2 More than 1500mm / sec 2When the acceleration is 70 mm / sec or less, it is easy to manufacture a cast wire rod 10 having a cast texture angle of 70° or less, as described below. A cast wire rod 10 having a cast texture angle of 70° or less is easy to satisfy the tin component ratio of 2.0 or less. 2 More than 1300mm / sec 2 or less than 100 mm / sec 2 More than 1000mm / sec 2 The following is also acceptable.

[0049] The deceleration rate from the above-mentioned drawing speed until the cast wire rod 10 stops is, for example, 50 mm / sec. 2 The deceleration is 50 mm / sec. 2 If the deceleration is 70 mm / sec or more, it is easy to produce a cast wire rod 10 having a cast texture angle of 70° or less, which will be described later. A cast wire rod 10 having a cast texture angle of 70° or less is easy to satisfy the tin component ratio of 2.0 or less. 2 or more, or 100 mm / sec 2 The deceleration may be, for example, 1000 mm / sec 2 Below, 800mm / sec 2 or less, or 600 mm / sec 2 That is, the deceleration is 50 mm / sec or less. 2 More than 1000mm / sec 2 Below, 70mm / sec 2 More than 800mm / sec 2 or less than 100 mm / sec 2 More than 600mm / sec 2 The following is also acceptable.

[0050] In the casting process, by keeping the acceleration and deceleration constant within the above ranges and repeatedly drawing and stopping the cast wire so that the ratio S1 / ST is 0.75 or less, it is easy to achieve a tin content of 2.0 or less.

[0051] The cast texture angle is determined as follows. As shown in FIG. 3, a longitudinal section of the cast wire 10 is taken. The longitudinal section is a cross section that passes through the center of the cast wire 10 and is along the axis of the cast wire 10. The longitudinal section is taken so that the length between the upper side 21 and the lower side 22 of the longitudinal section is the wire diameter x. In the longitudinal section of FIG. 3, the direction of the hollow arrow pointing from left to right on the page is the traveling direction of the cast wire 10.

[0052] An upper parallel line 31 is drawn from the upper side 21 to the lower side 22 of the longitudinal section, passing through a point 1 / 4 of the wire diameter x and parallel to the upper side 21. Five upper reference points 51 are drawn on the upper parallel line 31 at 6 mm intervals from the left side 23 to the right side 24. A lower parallel line 32 is drawn from the lower side 22 to the upper side 21 of the longitudinal section, passing through a point 1 / 4 of the wire diameter x and parallel to the lower side 22. Five lower reference points 52 are drawn on the lower parallel line 32 at 6 mm intervals from the left side 23 to the right side 24. The five upper reference points 51 are referred to as the first to fifth upper reference points 51 from left to right. The five lower reference points 52 are referred to as the first to fifth lower reference points 52 from left to right.

[0053] An upper cross line 41 is defined as a line extending along the grain boundary and intersecting with the upper parallel line 31. A lower cross line 42 is defined as a line extending along the grain boundary and intersecting with the lower parallel line 32. In any of the continuous casting methods described above, the grain boundaries are formed so as to incline from the axis of the cast wire 10 toward the upper edge 21 or the lower edge 22 as they move in the direction of travel of the cast wire 10. This is because the cast wire 10 is produced by cooling the molten metal from the outer periphery of the metal in contact with the mold toward the center and from the front to the rear in the direction of travel of the molten metal. As shown in FIG. 3, the upper cross line 41 and the lower cross line 42 are lines that incline toward the upper edge 21 or the lower edge 22 as they move in the direction of travel of the cast wire 10. For ease of explanation, seven upper cross lines 41 and six lower cross lines 42 are shown in FIG. 3. The seven upper cross lines 41 are numbered first to seventh upper cross lines 41 from left to right. The six lower crossing lines 42 are numbered first to sixth lower crossing lines 42 from left to right.

[0054] On the upper parallel line 31, the smaller angle θ is determined between each of the upper cross lines 41 that are closest to each of the first to fifth upper reference points 51 and the upper parallel line 31. That is, in FIG. 3, the smaller angle θ is determined between each of the second upper cross line 41, the fourth upper cross line 41, the fifth upper cross line 41, the sixth upper cross line 41, and the seventh upper cross line 41 and the upper parallel line 31. On the lower parallel line 32, the smaller angle θ is determined between each of the lower cross lines 42 that are closest to each of the first to fifth lower reference points 52 and the lower parallel line 32. That is, in FIG. 3, the smaller angle θ is determined between each of the second lower cross line 42, the third lower cross line 42, the fourth lower cross line 42, the fifth lower cross line 42, and the sixth lower cross line 42 and the lower parallel line 32. The average value of the 10 angles θ thus determined is the cast structure angle.

[0055] For ease of explanation, FIG. 3 shows an example in which there is no upper cross line 41 passing through the upper reference point 51. However, if there is an upper cross line 41 passing through the upper reference point 51, the upper cross line 41 passing through the upper reference point 51 is the upper cross line 41 that is closest to the upper reference point 51. This is also true for the lower cross line 42 that is closest to the lower reference point 52. In FIG. 3, near the second upper reference point 51, there are a third upper cross line 41 located to the left of the second upper reference point 51 and a fourth upper cross line 41 located to the right of the second upper reference point 51. In this case, the distance between the second upper reference point 51 and the fourth upper cross line 41 is closer than the distance between the second upper reference point 51 and the third upper cross line 41 on the upper parallel line 31. Therefore, the smaller angle θ between the fourth upper intersection line 41 and the upper parallel line 31 is found, but the smaller angle θ between the third upper intersection line 41 and the upper parallel line 31 is not found.

[0056] ≪Wire drawing process≫ In the wiredrawing process, the cast wire 10 is subjected to wiredrawing. The degree of wiredrawing can be appropriately selected depending on the wire diameter x of the cast wire 10 and the wire diameter 1d of the copper alloy wire 1 after wiredrawing. The degree of wiredrawing is, for example, 0.1 to 12.0, 0.2 to 11.0, or 0.3 to 10.0. The degree of wiredrawing is the absolute value, expressed as a natural logarithm, of the ratio of the cross-sectional area of ​​the wire before wiredrawing to the cross-sectional area of ​​the wire after wiredrawing. The wiredrawing is performed using, for example, an AWG (American Wire Gauge) standard die.

[0057] In the wire drawing step, the cast wire rod 10 may be rolled and then drawn.

[0058] The cast wire rod 10 having a tin content of 2.0 or less is less likely to break during wiredrawing. Therefore, the copper alloy wire 1 obtained by drawing the cast wire rod 10 having a tin content of 2.0 or less is less likely to break during the manufacturing process and has excellent productivity.

[0059] <Copper alloy stranded wire> As shown in Fig. 4, the copper alloy wire 1 of the embodiment can be used as an element wire of a copper alloy stranded wire 120. The copper alloy stranded wire 120 is formed by twisting together multiple copper alloy wires 1. The copper alloy stranded wire 120 has superior flexibility compared to a single copper alloy wire 1 having the same cross-sectional area, and each element wire is less likely to break even when subjected to impact and repeated bending. Therefore, the copper alloy stranded wire 120 has excellent impact resistance and fatigue properties. Fig. 4 shows an example of a copper alloy stranded wire 120 with seven concentrically twisted copper alloy wires 1, but the number of twisted copper alloy wires 1 and the twisting method can be changed as appropriate.

[0060] The copper alloy stranded wire 120 can be a compressed stranded wire that is twisted and then compressed. A compressed stranded wire has excellent stability in the twisted state. Furthermore, a compressed stranded wire tends to have better mechanical properties than a wire that is simply twisted, and can be made smaller in diameter.

[0061] <Insulated wire> The copper alloy wire 1 of the embodiment or the copper alloy stranded wire 120 of the embodiment can be used as a conductor for an electric wire. As shown in FIG. 4 , the covered electric wire 100 of the embodiment includes a conductor 110 and an insulating layer 130. The conductor 110 includes a copper alloy stranded wire 120. The insulating layer 130 covers the outer periphery of the conductor 110. The covered electric wire 100 has excellent impact resistance and fatigue properties because it includes the conductor 110 made of the copper alloy stranded wire 120, which has excellent impact resistance and fatigue properties. As another example of the covered electric wire 100, the conductor 110 may be a solid copper alloy wire 1.

[0062] The insulating material forming the insulating layer 130 can be selected appropriately. Examples of the insulating material include polyvinyl chloride (PVC), halogen-free resin, and a material with excellent flame retardancy. Known insulating materials can be used. The thickness of the insulating layer 130 can be selected appropriately within a range that provides a predetermined insulating strength.

[0063] <Wire with terminal> The covered electric wire 100 of the embodiment can be used as an electric wire for various applications, such as wire harnesses mounted on devices such as automobiles or airplanes, wiring for various electrical devices such as industrial robots, and wiring for buildings. When the covered electric wire 100 is used in a wire harness or the like, a terminal portion 210 is typically attached to the end of the covered electric wire 100. As shown in FIG. 5 , the terminal-fitted electric wire 200 of the embodiment includes the covered electric wire 100 of the embodiment and the terminal portion 210 attached to the end of the covered electric wire 100. This terminal-fitted electric wire 200 has excellent impact resistance and fatigue characteristics because it includes the covered electric wire 100, which has excellent impact resistance and fatigue characteristics. FIG. 5 illustrates an example of the terminal portion 210, which is a crimp terminal having a female or male fitting portion 212 at a first end, an insulation barrel portion 213 attached to the insulating layer 130 at a second end, and a wire barrel portion 211 attached to the conductor 110 at an intermediate portion. The crimp terminal is crimped onto the end of the conductor 110 exposed by removing the insulating layer 130 at the end of the coated electric wire 100, and is electrically and mechanically connected to the conductor 110. The terminal portion 210 may be a crimp type such as a crimp terminal, or may be connected by melting the conductor 110.

[0064] [Test example] A cast wire made of a copper alloy was prepared, and the presence or absence of wire breakage when this cast wire was subjected to wire drawing was examined.

[0065] <Sample> For all of Samples No. 1 to No. 3 and Samples No. 11 to No. 14, a cast wire was produced by intermittently continuously casting a molten copper alloy, and then this cast wire was subjected to wire drawing to produce a drawn wire.

[0066] In each sample, the molten copper alloy had a composition containing iron, phosphorus, and tin, with the remainder being copper and unavoidable impurities. The content ratio of each element contained in the molten metal of each sample is as shown in Table 1. The cast wire of each sample was produced by intermittent top-draw continuous casting. The length of the cast wire was 50 m. The wire diameter (mm) of the cast wire to be produced, the casting speed (mm / sec), the ratio S1 / ST of the time S1 for one withdrawal to the total time ST of the time S1 for one withdrawal and the time S2 for one stop, and the acceleration (mm / sec) from the stop state of the cast wire to the withdrawal speed were determined. 2 ), and the deceleration from the above withdrawal speed until the cast wire rod stops (mm / sec 2 ) are as shown in Table 1. In this example, the acceleration and deceleration were constant, and the ratio S1 / ST was varied. In Samples No. 1 to No. 3, the ratio S1 / ST was 0.75 or less, and the relationship between the casting speed y and the wire diameter x of the cast wire rod satisfied y≦155 / x.

[0067] The drawn wire material for each sample was produced by drawing the cast wire material. The drawing degree and the final wire diameter (mm) of the drawn wire material are shown in Table 2.

[0068] [Table 1]

[0069] <Cast structure angle> The cast structure angle (°) of each sample cast wire was determined. The method for determining the cast structure angle was as described above with reference to Figure 3. The results of the cast structure angle are shown in Table 1. The values ​​shown in Table 1 are rounded to the nearest digit.

[0070] <Component analysis> The composition of the drawn wire of each sample was investigated by mapping analysis using an electron probe microanalyzer (EPMA). As a result, the composition of the drawn wire of each sample was the same as the composition of the molten copper alloy. In other words, the composition of the drawn wire of each sample was as shown in Table 1.

[0071] In the cross section of the drawn wire of each sample, the ratio of the tin content in the center to the tin content in the outer periphery was determined. In addition, in the cross section of the drawn wire of each sample, the ratio of the phosphorus content in the center to the phosphorus content in the outer periphery was determined. The center is the interior of a circle centered on the central axis of the drawn wire and with a radius of 1 / 8 the wire diameter of the drawn wire. The outer periphery is the interior of a ring extending from the outer surface of the drawn wire toward the central axis and with a predetermined length of 1 / 8 the wire diameter of the drawn wire. The tin and phosphorus composition ratios of each sample were as shown in Table 2.

[0072] <Tensile strength> The tensile strength of each drawn wire sample was measured based on JIS Z 2241:2011. Specifically, a sample of each sample was prepared and subjected to a tensile test with a grip distance of 200 mm and a pulling speed of 20 mm / min until the sample broke. The maximum load value during this tensile test was divided by the cross-sectional area of ​​the sample to determine the tensile strength. The results are shown in Table 2.

[0073] <Whether or not wire breakage occurs during wire drawing> Each sample was examined to see if breakage occurred during wire drawing. The results are shown in Table 2. In the breakage column of Table 2, "No" means that the drawn wire material was produced without breakage. "Yes" means that breakage occurred.

[0074] [Table 2]

[0075] In the drawn wire materials of Samples No. 1 to No. 3, no breakage occurred during the wiredrawing process. In the drawn wire materials of Samples No. 1 to No. 3, the tin composition ratio was 2.0 or less. In the cast wire materials of Samples No. 1 to No. 3, the cast structure angle was 70° or less, and it is thought that the tin composition ratio was 2.0 or less. By subjecting cast wire materials with a tin composition ratio of 2.0 or less to wiredrawing, it was possible to perform the wiredrawing process without breakage, and it is thought that drawn wire materials with a tin composition ratio of 2.0 or less could be manufactured. All of the drawn wire materials of Samples No. 1 to No. 3, which did not suffer from breakage during the wiredrawing process, are thought to have excellent mechanical properties when used as drawn wire materials.

[0076] In the drawn wires of Samples No. 11 to No. 14, wire breakage occurred during wire drawing. In the drawn wires of Samples No. 11 to No. 14, the tin composition ratio exceeded 2.0. In the cast wires of Samples No. 11 to No. 14, the cast structure angle exceeded 70°, and it is believed that the tin composition ratio exceeded 2.0. When the tin composition ratio exceeded 2.0, tin was concentrated in the center of the cast wire, and the tin-concentrated area became embrittled. Therefore, it is believed that when cast wires with a cast structure angle of more than 70° and a tin composition ratio of more than 2.0 were subjected to wire drawing, wire breakage occurred starting from the tin-concentrated area. [Explanation of symbols]

[0077] 1 Copper alloy wire 2 Cross Section 3 center 4 Outer periphery 5 Outer surface 6 Middle section 1d wire diameter 3r radius 3L length 10 Cast wire rod 21 top side, 22 bottom side, 23 left side, 24 right side 31 upper parallel lines, 32 lower parallel lines 41 Upper cross line, 42 Lower cross line 51 upper reference point, 52 lower reference point x-ray diameter θ angle 100 Insulated wire 110 conductor, 120 copper alloy stranded wire, 130 insulating layer 200 Wires with terminals 210 terminal portion, 211 wire barrel portion 212 fitting portion, 213 insulation barrel portion

Claims

1. a composition made of a copper alloy containing 0.05% by mass or more and 1.60% by mass or less of iron, 0.01% by mass or more and 0.70% by mass or less of phosphorus, and 0.05% by mass or more and 0.70% by mass or less of tin; A wire diameter of 0.1 mm or more and 15.0 mm or less; a cross-section having a center and a periphery; The cross section is a cross section perpendicular to the longitudinal direction of the copper alloy wire, the center portion is within a circle having a center on the central axis of the copper alloy wire and a radius that is 1 / 8 of the wire diameter, the outer peripheral portion is a ring-shaped interior having a predetermined length of 1 / 8 of the wire diameter from the outer peripheral surface of the copper alloy wire toward the central axis, the ratio of the tin content in the central portion to the tin content in the outer circumferential portion is 2.0 or less; Copper alloy wire.

2. 2. The copper alloy wire according to claim 1, wherein a ratio of a phosphorus content in the central portion to a phosphorus content in the outer circumferential portion is 2.0 or less.

3. The copper alloy wire according to claim 1 or 2, wherein an outer peripheral surface of the copper alloy wire has processing marks.

4. The copper alloy wire according to claim 1 or 2, having a tensile strength of 250 MPa or more.

5. A plurality of the copper alloy wires according to claim 1 or 2 are twisted together. Copper alloy stranded wire.

6. A conductor and an insulating layer covering the outer periphery of the conductor, The conductor comprises the copper alloy stranded wire according to claim 5. Insulated wire.

7. A wire assembly comprising: the coated electric wire according to claim 6; and a terminal portion attached to an end of the coated electric wire. Wire with terminals.

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