Tungsten alloy wire and metal product

Abstract

A tungsten alloy wire (1) according to the present invention is used in an environment in which heat is affected at least once at a temperature of 1100 DEG C or higher. The tungsten alloy wire (1) contains rhenium at a content of 5 wt% or more and 26 wt% or less.

Description

Technical Field

[0001] The invention relates to tungsten alloy wire and metal products. Background Art

[0002] Patent Document 1 discloses a tungsten wire having a tensile strength of 3900 MPa or more.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-001660 Summary of the invention

[0006] Problems to be solved by the invention

[0007] An object of the present invention is to provide a tungsten alloy wire having excellent bending resistance and a metal product including the tungsten alloy wire.

[0008] Means for solving problems

[0009] A tungsten alloy wire according to one embodiment of the present invention is used in an environment subjected to heat of 1100° C. or higher at least once, and contains rhenium in an amount of 5 wt % to 26 wt %.

[0010] A metal product according to one aspect of the present invention includes the tungsten alloy wire according to the above aspect.

[0011] Effects of the Invention

[0012] According to the present invention, a tungsten alloy wire having excellent bending resistance and a metal product including the tungsten alloy wire can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic perspective view of a tungsten alloy wire according to an embodiment.

[0014] Figure 2A This is a schematic perspective view of a rod including a tungsten alloy wire according to an embodiment.

[0015] Figure 2B This is a schematic perspective view of an electrode including a tungsten alloy wire according to an embodiment.

[0016] Figure 2C This is a schematic perspective view of a twisted wire of a tungsten alloy wire according to an embodiment.

[0017] Figure 3 This is a graph showing the bending resistance of the tungsten alloy wire according to the embodiment after being affected by heat.

[0018] Figure 4It is a diagram showing an outline of a winding test of a tungsten alloy wire according to an embodiment. DETAILED DESCRIPTION

[0019] Hereinafter, the tungsten alloy wire and metal products of the embodiments of the present invention are described in detail using the accompanying drawings. It should be noted that the embodiments described below are all embodiments representing a specific example of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, configurations of constituent elements and connection forms, steps, order of steps, etc. shown in the following embodiments are examples, and the main purpose is not to limit the present invention. Therefore, the constituent elements not recorded in the independent claims among the constituent elements in the following embodiments are described as optional constituent elements.

[0020] In addition, each figure is a schematic diagram and may not be illustrated strictly. Therefore, for example, the scales in each figure may not be consistent. In addition, in each figure, the same symbols are marked for substantially the same structure, and repeated descriptions are omitted or simplified.

[0021] In the present specification, terms indicating shapes of elements such as a cylinder or a circle, and numerical ranges are not intended to be strictly defined but include substantially equivalent ranges, for example, differences of about several percent.

[0022] (Implementation Method)

[0023] [constitute]

[0024] First, for the tungsten alloy wire of this embodiment, use Figure 1 Provide explanation. Figure 1 It is a schematic perspective view of the tungsten alloy wire 1 according to the present embodiment.

[0025] like Figure 1 As shown in , the tungsten alloy wire 1 is stored by being wound on a reel 2. The reel 2 is sometimes referred to as a bobbin, a reel, a spool, or a drum. The tungsten alloy wire 1 has a total length of, for example, about 100 m in the meter (m) level to a kilometer (km) level, but is not particularly limited.

[0026] Figure 1 The tungsten alloy wire 1 shown in FIG. 1 is used in the manufacture of metal products. Figure 2A to Figure 2C Each of them is a schematic perspective view showing an example of a metal product including the tungsten alloy wire 1 according to the present embodiment.

[0027] Figure 2AThe rod 11 shown in the figure is an example of a metal product, and is provided with a tungsten alloy wire 1. Specifically, the rod 11 is a tungsten alloy wire 1 of a predetermined length. The length of the rod 11 is not particularly limited, and can be set to an appropriate length according to the application. The rod 11 is used as a part of various metal products or intermediate processing components provided with the tungsten alloy wire 1, but the application is not particularly limited. It should be noted that the rod is sometimes also called a needle.

[0028] Figure 2B The electrode 12 shown in the figure is an example of a metal product, and includes a tungsten alloy wire 1. Specifically, the electrode 12 is formed by finely processing the front end portion of the tungsten alloy wire 1 of a predetermined length. The front end shape of the electrode 12 is, for example, a conical shape, but is not limited thereto. The front end shape of the electrode 12 may also be a conical shape or a truncated cone shape with a rounded front end portion, or a pyramid or a truncated cone shape. The electrode 12 is used, for example, for electrical discharge machining, but the use is not particularly limited.

[0029] Figure 2C The twisted wire 13 shown in is an example of a metal product, and has a plurality of tungsten alloy wires 1. Specifically, the twisted wire 13 is a twisted yarn manufactured by twisting a plurality of tungsten alloy wires 1 of a specified length. It should be noted that the twisted wire 13 may also be a core-covered yarn having a tungsten alloy wire 1 as a core yarn or a sheath yarn. One of the core yarn and the sheath yarn may also be a metal wire other than the tungsten alloy wire 1, or may be a chemical fiber, a natural fiber, a regenerated fiber, or the like. The twisted wire 13 may also be further bundled and used in a rope or a cord, etc., and the use is not particularly limited.

[0030] It should be noted that examples of metal products using the tungsten alloy wire 1 are not limited to Figure 2A to Figure 2C For example, the metal product may be a saw wire, a mesh, a catheter, a fiber product, etc. The metal product may include the tungsten alloy wire 1 and a member formed using a material other than metal (eg, resin).

[0031] The tungsten alloy wire 1 of the present embodiment is used in an environment where it is subjected to heat of at least 1100°C or higher. Specifically, the tungsten alloy wire 1 is subjected to heat at least once when it is used in the manufacture of metal products or when it is used as a metal product. Specific examples of heat effects include, but are not particularly limited to, the case where the tungsten alloy wire 1 is welded to other metal components such as iron or used as a discharge electrode.

[0032] The tungsten alloy wire 1 can withstand bending even when subjected to heat above 1100°C. That is, the tungsten alloy wire 1 has excellent bending resistance. Even if the tungsten alloy wire 1 is bent at a predetermined curvature, no fracture or surface peeling will occur. It should be noted that 1100°C is an example of a temperature at which tungsten undergoes primary recrystallization.

[0033] In general, tungsten has the property of withstanding high temperatures. However, tungsten has a problem of weak crystal grain boundaries, that is, it is easy to crack with the crystal grain boundaries as the starting point. Specifically, under the influence of heat to the extent that the size of the grains changes (specifically, the temperature at which tungsten undergoes a recrystallization (1100°C) or above), not only will the tungsten grains become larger and the crystal grain boundaries become fewer, but oxygen will also enter the crystal grain boundaries. As the crystal grain boundaries become fewer, the amount of oxygen entering the crystal grain boundaries also becomes relatively more, so the strength of tungsten becomes weaker. As a result, when stress such as folding or bending is applied to tungsten after thermal influence, it becomes easy to crack with the crystal grain boundaries as the starting point, and the bending resistance deteriorates.

[0034] In contrast, the tungsten alloy wire 1 of the present embodiment contains tungsten and rhenium (Re), and tungsten and rhenium form a solid solution and are alloyed. The content of rhenium in the tungsten alloy wire 1 is 5wt% or more and 26wt% or less. Alternatively, the content of rhenium in the tungsten alloy wire 1 may be 6wt% or more, 7wt% or more, 8wt% or more, 9wt% or more, 10wt% or more, 12wt% or more, 15wt% or more, or 20wt% or more. In addition, the content of rhenium in the tungsten alloy wire 1 may be 25wt% or less, 20wt% or less, 15wt% or less, 12wt% or less, 10wt% or less, 9wt% or less, 8wt% or less, 7wt% or less, or 6wt% or less.

[0035] In the tungsten alloy wire 1, when the rhenium content is 5 wt% or more, the rhenium in the crystal grains can absorb oxygen that enters when affected by heat. This can reduce the amount of oxygen in the crystal grain boundaries, making it difficult to crack and suppressing the deterioration of bending resistance.

[0036] In the tungsten alloy wire 1, a solid solution of rhenium and tungsten can be formed when the rhenium content is 26 wt% or less. If the rhenium content exceeds 26 wt%, a solid solution cannot be formed, and the strength of the tungsten alloy wire 1 may decrease and become brittle.

[0037] [Bending resistance]

[0038] Next, the bending resistance of the tungsten alloy wire 1 of this embodiment was measured using Figure 3 and Figure 4 Provide explanation.

[0039] Figure 3 This is a graph showing the bending resistance of the tungsten alloy wire according to the present embodiment after being affected by heat. Figure 3Examples 1 to 8 shown in the are tungsten alloy wires having at least one of different wire diameters and components. The wire diameter of the tungsten alloy wire 1 of each example is within the range of 0.02 mm or more and 1.00 mm or less. In addition, the content of rhenium in the tungsten alloy wire 1 of each example is within the range of 5 wt % or more and 26 wt % or less. In addition, the content of tungsten in the tungsten alloy wire 1 of each example is 74 wt % or more and 95 wt % or less.

[0040] In addition, Figure 3 In the figure, the bending resistance of the tungsten wires of Comparative Examples 1 to 7 is also shown. Comparative Examples 1 to 3 are tungsten alloy wires containing rhenium. The rhenium content in the tungsten alloy wires of Comparative Examples 1 to 3 is 1wt% or less than 3wt%. The wire diameter of the tungsten alloy wires of Comparative Examples 1 to 3 is 0.10mm or 0.50mm. Comparative Examples 4 to 6 are tungsten wires containing potassium (potassium-doped tungsten wires). The potassium content in the potassium-doped tungsten wires of Comparative Examples 4 to 6 is 0.007wt%. The wire diameter of the potassium-doped tungsten wires of Comparative Examples 4 to 6 is 0.04mm, 0.10mm or 0.50mm. Comparative Example 7 is a pure tungsten wire without additives. It should be noted that in each embodiment and each comparative example, unavoidable impurities that cannot be avoided in manufacturing are contained in trace amounts.

[0041] The inventors of the present application heat-treated the tungsten alloy wires of Examples 1 to 8 and the tungsten alloy wires, potassium-doped tungsten wires, and pure tungsten wires of Comparative Examples 1 to 7 at a predetermined temperature. Five samples were prepared for each of the Examples and Comparative Examples, and each sample was heat-treated at a different temperature (1100°C, 1300°C, 1500°C, 1700°C, 2000°C). The heat treatment time does not particularly affect, but is, for example, about 1 minute.

[0042] After the heat treatment, a winding test was performed on each sample of each Example and each Comparative Example. Figure 4 This is a diagram showing an overview of a winding test of the tungsten alloy wire 1 according to the present embodiment.

[0043] In the winding test, a tungsten alloy wire 1 is wound around a rod-shaped core material 20 having a circular cross-sectional shape and a uniform diameter, and whether or not the tungsten alloy wire 1 is broken or peeled off on the surface is confirmed. The diameter R of the cross section of the core material 20 used in the winding test is set to be the same as the wire diameter φ of the tungsten alloy wire 1 being the object. That is, the smaller the wire diameter of the tungsten alloy wire 1, the smaller the curvature radius (larger the curvature) is used for bending (winding). For example, in the case of the tungsten alloy wire 1 with a wire diameter of 1.00 mm in Example 1, a cylindrical core material 20 with a wire diameter of 1.00 mm is used. In the case of the tungsten alloy wire 1 with a wire diameter of 0.04 mm in Example 7, a cylindrical core material 20 with a wire diameter of 0.04 mm is used. The same is true for the tungsten alloy wires, potassium-doped tungsten wires, and pure tungsten wires of Comparative Examples 1 to 7.

[0044] At once Figure 3 As for the tungsten alloy wires 1 of Examples 1 to 8, no fracture or surface peeling occurred at any temperature (indicated by "OK" in the figure). That is, regardless of the wire diameter, when the rhenium content is in the range of 5wt% to 26wt%, it is possible to achieve a tungsten alloy wire 1 that can withstand bending (excellent bending resistance) even when subjected to heat above 1100°C.

[0045] In contrast, as shown in Comparative Examples 1 to 3, when the rhenium content was 1 wt% or 3 wt%, fracture or surface peeling occurred (indicated by "NG" in the figure) except for the case of Comparative Example 3 subjected to the heat effect of 1100°C. In Comparative Example 3, it is assumed that since the wire diameter was 0.10 mm and thin, less oxygen was taken into the crystal grain boundary at a low temperature (1100°C) and fracture did not occur.

[0046] In addition, as shown in Comparative Examples 4 to 6, in the case of potassium-doped tungsten wire, fracture or surface peeling occurred except for the case where the wire diameter was small and the heat treatment temperature was low (1100°C in Comparative Example 5 and 1100°C and 1300°C in Comparative Example 6). It should be noted that potassium, unlike rhenium, exists at the crystal grain boundary and has no effect of taking up oxygen.

[0047] As shown in Comparative Example 7, in the case of the pure tungsten wire, oxygen generated by thermal influence enters the crystal grain boundary, thereby causing fracture or surface peeling.

[0048] [Effects, etc.]

[0049] As described above, the tungsten alloy wire 1 of the present embodiment is used in an environment subjected to heat of 1100° C. or higher at least once, and contains rhenium in an amount of 5 wt % to 26 wt %.

[0050] Thus, the tungsten alloy wire 1 contains 5 wt% or more of rhenium, so that rhenium can absorb oxygen that enters the crystal grain boundary when it is affected by heat, and can suppress the occurrence of cracks starting from the crystal grain boundary. Therefore, even if it is affected by heat, it is not easy to break the wire, and it is possible to achieve a tungsten alloy wire 1 with excellent bending resistance. In addition, by setting the rhenium content to 26 wt% or less, an alloy (solid solution) of rhenium and tungsten can be formed, so the strength of the tungsten alloy wire 1 can be improved.

[0051] Furthermore, the metal product of the present embodiment includes the tungsten alloy wire 1. For example, the metal product is a rod 11, an electrode 12, or a twisted wire 13.

[0052] Thus, even if the tungsten alloy wire 1 is affected by heat during the manufacture or use of the metal product, it is possible to withstand bending, thereby suppressing the degradation of the quality of the metal product.

[0053] [Manufacturing method]

[0054] The tungsten alloy wire 1 of the present embodiment can be produced, for example, by the following method.

[0055] First, tungsten powder and rhenium powder are mixed, compacted, and sintered to form an ingot. The rhenium content can be adjusted to 5 wt % or more and 26 wt % or less by adjusting the mixing ratio of the tungsten powder and the rhenium powder.

[0056] Next, the ingotized tungsten block is subjected to die forging, which compresses and stretches it from the periphery, to form a wire. After that, wire drawing is performed using a wire drawing die. Wire drawing is performed using a plurality of wire drawing dies with different hole diameters in a sequence of gradually decreasing hole diameters.

[0057] By properly adjusting the hole diameter of the wire drawing die, it is possible to produce Figure 3 The tungsten alloy wire 1 has a diameter of 0.02 mm to 1.00 mm as shown in FIG. It should be noted that heating at a predetermined temperature may be performed during the wire drawing. In addition, the tungsten alloy wire 1 after the wire drawing may be subjected to surface treatment such as electrolytic polishing.

[0058] (other)

[0059] As mentioned above, the tungsten alloy wire and the metal product of the present invention have been described based on the above-mentioned embodiments, etc., but the present invention is not limited to the above-mentioned embodiments.

[0060] For example, the tungsten alloy wire may also contain ruthenium (Ru) or cobalt (Co) instead of rhenium. For example, the tungsten content of the tungsten alloy wire is 99.8wt%, the ruthenium content is 0.2wt%, and a trace amount of impurities may also be contained. After the tungsten alloy wire is heat-treated, the winding test is carried out. The result shows that no deterioration of bending resistance is observed in any case where the heat treatment temperature is 1100°C, 1300°C, 1500°C, 1700°C, and 2000°C.

[0061] In addition, the present invention also includes the following aspects: aspects obtained by implementing various modifications that can be conceived by those skilled in the art to the various embodiments, and aspects achieved by arbitrarily combining the constituent elements and functions in the various embodiments without departing from the gist of the present invention.

[0062] Explanation of symbols

[0063] 1. Tungsten Alloy Wire

[0064] 11 sticks

[0065] 12 Electrodes

[0066] 13 Twisting

Claims

1. A tungsten alloy wire used in an environment subjected to heat of 1100° C. or higher at least once, Rhenium is contained in a content of 5 wt % or more and 26 wt % or less.

2. A metal product comprising the tungsten alloy wire according to claim 1.

3. The metal product according to claim 2, wherein: The metal product is a rod, an electrode or a twisted wire.

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