Tungsten alloy wire and metal product

Abstract

To provide a tungsten alloy wire with superior flex resistance.SOLUTION: A tungsten alloy wire 1 is used in an environment that receives at least one thermal impact of at least 1100°C. The tungsten alloy wire 1 contains rhenium at a content of 5 to 26 wt.% inclusive.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

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

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-001660 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to provide a tungsten alloy wire having excellent bending resistance and a metal product including the tungsten alloy wire. [Means for solving the problem]

[0005] The tungsten alloy wire of one aspect of the present invention is used under the environment that is subjected to the heat influence of 1100 ℃ or more at least once, and comprises rhenium content of 5wt% or more and 26%wt% or less.

[0006] A metal product according to one aspect of the present invention includes the tungsten alloy wire according to the above aspect. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a tungsten alloy wire having excellent bending resistance and a metal product including the tungsten alloy wire. [Brief explanation of the drawings]

[0008] [Figure 1]FIG. 1 is a schematic perspective view of a tungsten alloy wire according to an embodiment. [Figure 2A] FIG. 2A is a schematic perspective view of a rod including a tungsten alloy wire according to an embodiment. [Figure 2B] FIG. 2B is a schematic perspective view of an electrode including a tungsten alloy wire according to an embodiment. [Figure 2C] FIG. 2C is a schematic perspective view of a stranded wire including tungsten alloy wires according to an embodiment. [Figure 3] FIG. 3 is a diagram showing the bending resistance of the tungsten alloy wire according to the embodiment after being subjected to a thermal effect. [Figure 4] FIG. 4 is a diagram showing an outline of a coiling test of a tungsten alloy wire according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Below, the tungsten alloy wire and metal product according to the embodiment of the present invention will be described in detail with the drawings.It should be noted that the embodiment described below is all a specific example of the present invention.Therefore, the numerical value, shape, material, components, the arrangement and connection form of components, steps, step order, etc. shown in the following embodiment are only examples, and do not intend to limit the present invention.Therefore, among the components in the following embodiment, the components that are not described in independent claims will be described as optional components.

[0010] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the figures do not necessarily match. Furthermore, in each figure, substantially the same components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0011] Furthermore, in this specification, terms indicating the shape of elements such as cylinder or circle, as well as numerical ranges, are not expressions that express only the strict meaning, but are expressions that include a substantially equivalent range, for example, a difference of about several percent.

[0012] (Embodiment) [composition] First, the tungsten alloy wire according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic perspective view of a tungsten alloy wire 1 according to this embodiment.

[0013] As shown in Fig. 1, tungsten alloy wire 1 is wound around a reel 2 and stored. Reel 2 may be called bobbin, reel, spool or drum. For example, tungsten alloy wire 1 has a total length of about 100m (meter order) to km order, but is not particularly limited.

[0014] The tungsten alloy wire 1 shown in Fig. 1 is used to manufacture a metal product. Fig. 2A to Fig. 2C are each a schematic perspective view showing an example of a metal product including the tungsten alloy wire 1 according to the present embodiment.

[0015] The rod 11 shown in FIG. 2A is an example of a metal product, and includes 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 an appropriate length depending on the application. The rod 11 is used as a part or intermediate processed member of various metal products that include a tungsten alloy wire 1, and the application is not particularly limited. The rod may also be called a pin.

[0016] The electrode 12 shown in FIG. 2B is an example of a metal product and includes a tungsten alloy wire 1. Specifically, the electrode 12 is a tungsten alloy wire 1 of a predetermined length, the tip of which is thinned. The tip shape of the electrode 12 is, for example, a cone shape, but is not limited thereto. The tip shape of the electrode 12 may be a cone shape or a truncated cone shape with a rounded tip, or a pyramid or a truncated pyramid shape. The electrode 12 is used, for example, for electrical discharge machining, but its use is not particularly limited.

[0017] The twisted wire 13 shown in FIG. 2C is an example of a metal product and includes a plurality of tungsten alloy wires 1. Specifically, the twisted wire 13 is a ply-twisted yarn produced by plying and twisting a plurality of tungsten alloy wires 1 of a predetermined length. The twisted wire 13 may also be a covered yarn that includes a tungsten alloy wire 1 as a core yarn or a sheath yarn. One of the core yarn and the sheath yarn may be a metal wire other than the tungsten alloy wire 1, and may be a chemical fiber, a natural fiber, a recycled fiber, or the like. The twisted wire 13 may also be bundled together and used as a rope or a string, and the use is not particularly limited.

[0018] In addition, examples of metal products using the tungsten alloy wire 1 are not limited to those shown in Figures 2A to 2C. For example, the metal product may be a saw wire, a mesh, a catheter, a textile product, etc. The metal product may include the tungsten alloy wire 1 and a member formed using a material other than metal (for example, resin).

[0019] The tungstenalloy wire 1 of the present embodiment is used under the environment that is subjected to the heat influence of 1100 ℃ or more at least once.Specifically, the tungstenalloy wire 1 is subjected to the heat influence at least once when it is processed for manufacturing metal products or when it is used as metal products.The specific example of the heat influence is, for example, when the tungstenalloy wire 1 is welded to other metal members such as iron, or when it is used as discharge electrode, but is not particularly limited.

[0020] The tungsten alloy wire 1 is strong against bending even when it is subjected to the heat influence of 1100 ℃ or more. That is, the tungsten alloy wire 1 has excellent bending resistance. Even when the tungsten alloy wire 1 is bent with a predetermined curvature, it does not break or peel off on the surface. Note that 1100 ℃ is an example of the temperature at which tungsten undergoes primary recrystallization.

[0021] Generally, tungsten has the property of withstanding high temperatures. However, tungsten has a problem in that its grain boundaries are weak, i.e., cracks are likely to occur at the grain boundaries. Specifically, when tungsten is subjected to a heat effect to the extent that the size of the grains changes (specifically, above the temperature at which tungsten undergoes primary recrystallization (1100°C)), not only do the tungsten grains grow and the number of grain boundaries decrease, but oxygen also penetrates the grain boundaries. As the number of grain boundaries decreases, the amount of oxygen that penetrates the grain boundaries also increases relatively, weakening the strength of the tungsten. As a result, when stress such as folding or bending is applied to tungsten after the heat effect, cracks are likely to occur at the grain boundaries, resulting in a deterioration in flex resistance.

[0022] On the other hand, the tungsten alloy wire 1 of the present embodiment comprises tungsten and rhenium (Re), and tungsten and rhenium form solid solution and are alloyed.The rhenium content in the tungstenalloy wire 1 is more than 5wt% and less than 26wt%.

[0023] In the tungsten alloy wire 1, the rhenium content is 5 wt% or more, so that the rhenium present in the crystal grains can absorb the oxygen that gets into the wire when it is subjected to heat. This reduces the amount of oxygen present in the crystal grain boundaries, making it difficult for cracks to occur and preventing deterioration of bending resistance.

[0024] In addition, in the tungsten alloy wire 1, the rhenium content is 26wt% or less, so that the solid solution of rhenium and tungsten can be formed.If the rhenium content is more than 26wt%, the solid solution cannot be formed, and the strength of the tungsten alloy wire 1 may be reduced and become brittle.

[0025] [Bending resistance] Next, the bending resistance of the tungsten alloy wire 1 according to this embodiment will be described with reference to FIGS.

[0026] Fig. 3 is a diagram showing the bending resistance of the tungsten alloy wire according to the present embodiment after being subjected to heat influence. Examples 1 to 8 shown in Fig. 3 are tungsten alloy wires that differ in at least one of wire diameter and composition. The wire diameter of the tungstenalloy wire 1 according to each example is within the range of 0.02mm or more and 1.00mm or less. The rhenium content in the tungstenalloy wire 1 according to each example is within the range of 5wt% or more and 26wt% or less. The tungsten content in the tungstenalloy wire 1 according to each example is within the range of 74wt% or more and 95wt% or less.

[0027] FIG. 3 also shows the bending resistance of the tungsten wires according to Comparative Examples 1 to 7. Comparative Examples 1 to 3 are tungsten alloy wires containing rhenium. The rhenium content in the tungsten alloy wires according to Comparative Examples 1 to 3 is 1 wt% or 3 wt% or less. The wire diameter of the tungsten alloy wires according to Comparative Examples 1 to 3 is 0.10 mm or 0.50 mm. Comparative Examples 4 to 6 are tungsten wires containing potassium (potassium-doped tungsten wires). The potassium content in the potassium-doped tungsten wires according to Comparative Examples 4 to 6 is 0.007 wt%. The wire diameter of the potassium-doped tungsten wires according to Comparative Examples 4 to 6 is 0.04 mm, 0.10 mm, or 0.50 mm. Comparative Example 7 is a pure tungsten wire containing no additives. Note that each Example and Comparative Example contains a small amount of unavoidable impurities that are unavoidable during manufacturing.

[0028] The inventors of the present application performed heat treatment at a predetermined temperature on the tungsten alloy wires according to Examples 1 to 8, and the tungsten alloy wires, potassium-doped tungsten wires, and pure tungsten wires according to Comparative Examples 1 to 7. Five samples were prepared for each Example and Comparative Example, and each sample was subjected to heat treatment at a different temperature (1100°C, 1300°C, 1500°C, 1700°C, 2000°C). The heat treatment time does not have any particular effect, but is, for example, about 1 minute.

[0029] After the heat treatment, a coiling test was carried out on each sample of each example and each comparative example. Fig. 4 is a diagram showing an outline of the coiling test of the tungsten alloy wire 1 according to the present embodiment.

[0030] In the coiling test, a tungsten alloy wire 1 was wound around a rod-shaped core material 20 having a circular cross section and a uniform diameter, and it was confirmed whether or not the tungsten alloy wire 1 broke or peeled off. The cross-sectional diameter R of the core material 20 used in the coiling test was the same as the wire diameter φ of the target tungsten alloy wire 1. That is, the smaller the wire diameter of the tungsten alloy wire 1, the smaller the curvature radius (larger curvature) at which bending (coiling) was performed. For example, in the case of the tungsten alloy wire 1 having a wire diameter of 1.00 mm in Example 1, a cylindrical core material 20 having a wire diameter of 1.00 mm was used. In the case of the tungsten alloy wire 1 having a wire diameter of 0.04 mm in Example 7, a cylindrical core material 20 having a wire diameter of 0.04 mm was used. The same applies to the tungsten alloy wires, potassium-doped tungsten wires, and pure tungsten wires in Comparative Examples 1 to 7.

[0031] In the tungsten alloy wire 1 of embodiment 1 to 8 in Fig. 3, no breakage or surface peeling occurs at any temperature (shown as "OK" in the figure).That is, regardless of wire diameter, when the rhenium content is in the range of 5wt% or more and 26wt% or less, even if it is subjected to the heat influence of 1100 ℃ or more, the tungsten alloy wire 1 can be realized to be strong against bending (having excellent bending resistance).

[0032] 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 in all cases (indicated by "NG" in the figure), except for Comparative Example 3, which was subjected to a heat effect at 1100°C. In Comparative Example 3, the wire diameter was 0.10 mm, which was thin, so it is assumed that at the low temperature (1100°C), there was little oxygen absorbed into the grain boundaries, and fracture did not occur.

[0033] Furthermore, as shown in Comparative Examples 4 to 6, in the case of potassium-doped tungsten wires, fracture or surface peeling occurred in all cases except when 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). Note that, unlike rhenium, potassium exists at the grain boundaries and does not have the effect of capturing oxygen.

[0034] As shown in Comparative Example 7, in the case of the pure tungsten wire, oxygen due to the heat influence penetrated into the grain boundaries, causing fracture or surface peeling.

[0035] [Effects, etc.] As described above, the tungstenalloy wire 1 of the present embodiment is the tungstenalloy wire that is used under the environment that is subjected to the thermal influence of 1100 ℃ or more at least once, and comprises rhenium in the content of 5wt% or more and 26%wt% or less.

[0036] Therefore, by containing 5 wt% or more of rhenium, the tungsten alloy wire 1 can absorb oxygen that enters the grain boundary when it is subjected to heat, and can suppress the occurrence of cracks originating from the grain boundary. Therefore, even if it is subjected to heat, it is difficult for breakage to occur, and it is possible to realize a tungsten alloy wire 1 with excellent bending resistance. In addition, by making the rhenium content 26 wt% or less, it is possible to form an alloy (solid solution) between rhenium and tungsten, and therefore the strength of the tungsten alloy wire 1 can be increased.

[0037] The metal product according to this embodiment includes a tungsten alloy wire 1. For example, the metal product is a rod 11, an electrode 12, or a stranded wire 13.

[0038] Therefore, even if the tungsten alloy wire 1 is subjected to heat influence during the manufacturing or use of the metal product, it is strong against bending, and therefore it is possible to suppress deterioration of the quality of the metal product.

[0039] [Manufacturing method] The tungsten alloy wire 1 according to this embodiment can be manufactured, for example, by the following method.

[0040] First, tungsten powder and rhenium powder are mixed, press-molded, and sintered to form an ingot. By adjusting the mixing ratio of the tungsten powder and the rhenium powder, the rhenium content can be adjusted to between 5 wt% and 26 wt%.

[0041] Next, the tungsten ingot is swaged, which compresses and stretches it from the periphery, to form it into a wire. It is then drawn using a wire-drawing die. The wire is drawn using multiple wire-drawing dies with different hole diameters, in order of decreasing hole diameter.

[0042] By adjusting the hole diameter of wire drawing die appropriately, can produce the tungsten alloy wire 1 in the range of 0.02mm to 1.00mm as shown in Figure 3. In addition, when drawing wire, can be heated at a predetermined temperature. In addition, the tungsten alloy wire 1 after drawing can be subjected to surface treatment such as electrolytic polishing.

[0043] (others) Above, the tungsten alloy wire and metal product of the present invention are explained based on the above-mentioned embodiment, but the present invention is not limited to the above-mentioned embodiment.

[0044] For example, tungsten alloy wire can contain ruthenium (Ru) or cobalt (Co) instead of rhenium.For example, tungsten alloy wire can contain 99.8wt% of tungsten, 0.2wt% of ruthenium, and contain trace amounts of impurities.After heat treatment of this tungsten alloy wire, coiling test is carried out, and no deterioration in bending resistance is observed in any of the cases where the heat treatment temperature is 1100 ℃, 1300 ℃, 1500 ℃, 1700 ℃, and 2000 ℃.

[0045] In addition, the present invention also includes forms obtained by applying various modifications to each embodiment that a person skilled in the art would think of, and forms realized by arbitrarily combining the components and functions of each embodiment within the scope of the present invention. [Explanation of symbols]

[0046] 1. Tungsten alloy wire 11 bars 12 electrodes 13 Stranded Wire

Claims

1. A tungsten alloy wire used in an environment where it is subjected to heat influence of 1100°C or more at least once, Contains rhenium in an amount of 5 wt% or more and 26 wt% or less; Tungsten alloy wire.

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

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

Images