阅读说明：本技术 Ni基超耐热合金线材的制造方法和Ni基超耐热合金线材 (Method for producing Ni-based superalloy wire and Ni-based superalloy wire ) 是由 A·A·B·穆哈默德 韩刚 向瀬莱米 于 2018-06-26 设计创作，主要内容包括：本发明提供弯曲加工性优异的Ni基超耐热合金线材的制造方法和Ni基超耐热合金线材。一种Ni基超耐热合金线材的制造方法,其具备：棒材准备工序,准备Ni基超耐热合金的棒材；和棒材加工工序,从该棒材的圆周面朝向轴心地以500℃以下的温度进行多次单次加工率为40％以下的塑性加工,直至使得累积加工率成为60％以上,压缩上述棒材的截面积。而且,为一种Ni基超耐热合金线材的制造方法,其具备：热处理工序,对通过上述棒材加工工序而得到的Ni基超耐热合金线材进一步进行超过500℃的温度下的热处理。通过这些制造方法得到的Ni基超耐热合金线材具有塑性加工组织或再结晶组织。(The invention provides a method for manufacturing a Ni-based super heat-resistant alloy wire rod with excellent bending workability and the Ni-based super heat-resistant alloy wire rod. A method for producing a Ni-based superalloy wire, comprising: a bar material preparation step of preparing a bar material of a Ni-based superalloy; and a bar material processing step of performing plastic working with a single working ratio of 40% or less from the circumferential surface of the bar material toward the axial center at a temperature of 500 ℃ or less a plurality of times until the cumulative working ratio becomes 60% or more, and reducing the cross-sectional area of the bar material. Also disclosed is a method for producing a Ni-based superalloy wire, which comprises: and a heat treatment step of further heat-treating the Ni-based superalloy wire obtained in the bar processing step at a temperature exceeding 500 ℃. The Ni-based superalloy wire obtained by these production methods has a plastic worked structure or a recrystallized structure.)

1. A method for manufacturing a Ni-based superalloy wire, comprising:

a bar material preparation step of preparing a bar material of a Ni-based superalloy; and the combination of (a) and (b),

and a bar material processing step of performing plastic working with a single working ratio of 40% or less from the circumferential surface of the bar material toward the axial center at a temperature of 500 ℃ or less a plurality of times until the cumulative working ratio becomes 60% or more, and compressing the cross-sectional area of the bar material.

2. The method of manufacturing a Ni-based superalloy wire according to claim 1, wherein the cumulative working ratio is 70% or more.

3. The method of manufacturing a Ni-based superalloy wire according to claim 1 or 2, wherein the single pass reduction rate is 30% or less.

4. The method of manufacturing a Ni-based superalloy wire according to any one of claims 1 to 3, wherein in the rod processing step, a cross-sectional area of the rod is compressed to a wire diameter of a final Ni-based superalloy wire.

5. The method for producing the Ni-based superalloy wire according to any one of claims 1 to 4, comprising:

and a heat treatment step of heat-treating the Ni-based superalloy wire obtained in the bar processing step at a temperature exceeding 500 ℃.

6. The method for producing the Ni-based superalloy wire according to any of claims 1 to 5, wherein the Ni-based superalloy has a precipitation-strengthening type composition in which an equilibrium precipitation amount of γ' at 700 ℃ is 35 mol% or more.

7. The method for producing the Ni-based superalloy wire according to claim 6, wherein the composition is composed of, in mass%, C: 0-0.25%, Cr: 8.0-25.0%, Al: 0.5 to 8.0%, Ti: 0.4 to 7.0%, Co: 0-28.0%, Mo: 0-8.0%, W: 0-6.0%, Nb: 0-4.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0-0.300%, and the balance of Ni and impurities.

8. The method for producing the Ni-based superalloy wire according to claim 7, wherein the composition is composed of, in mass%, C: 0-0.2%, Cr: 8.0-22.0%, Al: 2.0-8.0%, Ti: 0.4 to 7.0%, Co: 0-28.0%, Mo: 2.0-7.0%, W: 0-6.0%, Nb: 0-4.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0-0.300%, and the balance of Ni and impurities.

9. The method for producing the Ni-based superalloy wire according to claim 7, wherein the composition is composed of, in mass%, C: 0-0.2%, Cr: 20.0 to 25.0%, Al: 0.5 to 5.0%, Ti: 1.0-6.0%, Co: 10.0 to 28.0%, Mo: 0-8.0%, W: 0.5 to 5.0%, Nb: 0.1 to 3.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0.010-0.300%, and the balance of Ni and impurities.

10. A Ni-based superalloy wire, characterized in that,

the precipitation-strengthened type composite material has the following composition: a composition consisting of C: 0-0.25%, Cr: 8.0-25.0%, Al: 0.5 to 8.0%, Ti: 0.4 to 7.0%, Co: 0-28.0%, Mo: 0-8.0%, W: 0-6.0%, Nb: 0-4.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0-0.300%, and the balance of Ni and impurities; the equilibrium deposition amount of gamma' at 700 ℃ is 35 mol% or more,

the Ni-based superalloy wire has a plastic worked structure or a recrystallized structure.

11. The Ni-based superalloy wire according to claim 10, wherein the composition consists of, in mass%, C: 0-0.2%, Cr: 8.0-22.0%, Al: 2.0-8.0%, Ti: 0.4 to 7.0%, Co: 0-28.0%, Mo: 2.0-7.0%, W: 0-6.0%, Nb: 0-4.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0-0.300%, and the balance of Ni and impurities.

12. The Ni-based superalloy wire according to claim 10, wherein the composition consists of, in mass%, C: 0-0.2%, Cr: 20.0 to 25.0%, Al: 0.5 to 5.0%, Ti: 1.0-6.0%, Co: 10.0 to 28.0%, Mo: 0-8.0%, W: 0.5 to 5.0%, Nb: 0.1 to 3.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0.010-0.300%, and the balance of Ni and impurities.

13. The Ni-based superalloy wire according to any of claims 10 to 12, wherein the Ni-based superalloy wire does not break when a bending displacement of 50mm is reached in a bending test based on a cantilever beam as follows: a Ni-based superalloy wire having a length of 150mm was prepared, a position 25mm from one end of the Ni-based superalloy wire was constrained, and a load was applied to a position 25mm from the other end.

Technical Field

The present invention relates to a method for producing a Ni-based superalloy wire and a Ni-based superalloy wire.

Background

As aircraft engines and power generation gas turbines have become more highly functional and less fuel-consuming, heat-resistant parts used for the engines have been required to have excellent heat resistance (high-temperature strength). As a material for the heat-resistant member, a Ni-based superalloy is often used (non-patent documents 1 and 2). The Ni-based superalloy has a structure containing a large amount of γ 'as a precipitation hardening phase, wherein γ' is Ni₃The precipitation strengthening phase of the intermetallic compound mainly composed of Al improves the heat resistance. Further, the 713 alloy and the 939 alloy (for example, the symbols IN the IN713 and IN939 alloys are typical) are Ni-based superalloys excellent IN heat resistance by containing a large amount of Al, Ti, and Nb as γ' forming elements.

In recent years, there has been an increasing demand for repairing a heat-resistant member made of a Ni-based superalloy by welding or the like, or for producing the heat-resistant member itself by three-dimensional molding by a stack molding method using laser or electron beam as a heat source. Further, as a shaped material in this case, a "wire rod" of a Ni-based superalloy is demanded. The wire diameter (diameter) of the wire rod is, for example, as small as 5mm or less, and further as small as 3mm or less.

Disclosure of Invention

Problems to be solved by the invention

Conventional Ni-based superalloy wire rods are provided as individual "rods" because they are difficult to bend into a coil shape because they are broken (fractured) immediately after being bent. Therefore, when the heat-resistant member is repaired or the heat-resistant member itself is manufactured using the Ni-based superalloy wire, a new Ni-based superalloy wire needs to be attached every time one Ni-based superalloy wire is consumed, and the supply of the Ni-based superalloy wire is interrupted. Therefore, if the Ni-based superalloy wire rod can be bent into a coil shape, the Ni-based superalloy wire rod can be provided in a "coil" form, and the Ni-based superalloy wire rod can be continuously fed out from the coil and supplied, and therefore, the work efficiency is improved.

The object of the present invention is to provide: a method for producing a Ni-based superalloy wire rod having excellent bending workability, and a Ni-based superalloy wire rod.

Means for solving the problems

The present inventors have studied the bending workability of a Ni-based superalloy wire. As a result, they found that: when a tensile strength is imparted to the Ni-based superalloy wire, the breakage of the Ni-based superalloy wire during the bending process is suppressed, and the improvement of the bending workability of the Ni-based superalloy wire is effective. Further, the present inventors have found a production method effective for producing such a Ni-based superalloy wire, and have specified a structural form exhibited when the Ni-based superalloy wire is excellent in bending workability, and have completed the present invention.

That is, the present invention is a method for producing a Ni-based superalloy wire, including: a bar material preparation step of preparing a bar material of a Ni-based superalloy; and a bar material processing step of performing plastic working with a single working ratio of 40% or less from the circumferential surface of the bar material toward the axial center at a temperature of 500 ℃ or less a plurality of times until the cumulative working ratio becomes 60% or more, and reducing the cross-sectional area of the bar material. In this case, the cumulative working ratio is preferably 70% or more. The single working ratio is preferably 30% or less. In the above-described bar material processing step, the cross-sectional area of the bar material is preferably reduced to the wire diameter of the final Ni-based superalloy wire rod.

Further, the method for producing a Ni-based superalloy wire includes: and a heat treatment step of further heat-treating the Ni-based superalloy wire obtained in the bar processing step at a temperature exceeding 500 ℃.

The Ni-based superalloy preferably has a precipitation-strengthening type composition in which an equilibrium precipitation amount of γ' at 700 ℃. Further, the composition of the component is specifically preferably composed of, in mass%, C: 0-0.25%, Cr: 8.0-25.0%, Al: 0.5 to 8.0%, Ti: 0.4 to 7.0%, Co: 0-28.0%, Mo: 0-8.0%, W: 0-6.0%, Nb: 0-4.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0-0.300%, and the balance of Ni and impurities.

As one of the specific component compositions, there may be mentioned a composition consisting of, in mass%, C: 0-0.2%, Cr: 8.0-22.0%, Al: 2.0-8.0%, Ti: 0.4 to 7.0%, Co: 0-28.0%, Mo: 2.0-7.0%, W: 0-6.0%, Nb: 0-4.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0-0.300%, and the balance of Ni and impurities.

In addition, as another one of the specific component compositions, there may be mentioned a composition consisting of, in mass%, C: 0-0.2%, Cr: 20.0 to 25.0%, Al: 0.5 to 5.0%, Ti: 1.0-6.0%, Co: 10.0 to 28.0%, Mo: 0-8.0%, W: 0.5 to 5.0%, Nb: 0.1 to 3.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0.010-0.300%, and the balance of Ni and impurities.

Further, the present invention is a Ni-based superalloy wire having a precipitation hardening type composition of: a composition consisting of C: 0-0.25%, Cr: 8.0-25.0%, Al: 0.5 to 8.0%, Ti: 0.4 to 7.0%, Co: 0-28.0%, Mo: 0-8.0%, W: 0-6.0%, Nb: 0-4.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0-0.300%, and the balance of Ni and impurities; the equilibrium precipitation amount of gamma' at 700 ℃ is 35 mol% or more, and the Ni-based superalloy wire has a plastic worked structure or a recrystallized structure.

Further, as one of the above-mentioned component compositions, there may be mentioned a composition consisting of, in mass%, C: 0-0.2%, Cr: 8.0-22.0%, Al: 2.0-8.0%, Ti: 0.4 to 7.0%, Co: 0-28.0%, Mo: 2.0-7.0%, W: 0-6.0%, Nb: 0-4.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0-0.300%, and the balance of Ni and impurities.

In addition, as another one of the above-mentioned component compositions, there may be mentioned a composition consisting of, in mass%, C: 0-0.2%, Cr: 20.0 to 25.0%, Al: 0.5 to 5.0%, Ti: 1.0-6.0%, Co: 10.0 to 28.0%, Mo: 0-8.0%, W: 0.5 to 5.0%, Nb: 0.1 to 3.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0.010-0.300%, and the balance of Ni and impurities.

The Ni-based superalloy wire preferably does not break when the bending displacement reaches 50mm in a bending test based on a cantilever beam as follows: a Ni-based superalloy wire having a length of 150mm was prepared, a position 25mm from one end of the Ni-based superalloy wire was constrained, and a load was applied to a position 25mm from the other end.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there can be provided: a method for producing a Ni-based superalloy wire rod having excellent bending workability, and a Ni-based superalloy wire rod.

Drawings

FIG. 1 is a photograph used as a drawing showing an example of a cross-sectional microstructure of a Ni-based superalloy wire rod produced in an example of the present invention.

FIG. 2 is a photograph as an illustration showing an example of a cross-sectional microstructure of a Ni-based superalloy wire rod produced in another example of the present invention.

FIG. 3 is a photograph as an illustration showing an example of a cross-sectional microstructure of a Ni-based superalloy wire rod produced in another example of the present invention.

Detailed Description

Conventional Ni-based superalloy wires are poor in bending workability, and sometimes break immediately after bending. This is because the conventional Ni-based superalloy wire rod is molded by casting, and has a brittle cast structure. In the case of such a wire rod shaped by casting, it is difficult to improve the bending workability even if the wire rod is further subjected to a light processing for adjusting the shape or a heat treatment for removing the cast structure.

Therefore, the present inventors have studied the bending workability of the Ni-based superalloy wire. As a result, they found that: by eliminating the cast structure of the Ni-based superalloy wire, tensile strength can be imparted to the Ni-based superalloy wire, and the bending workability of the Ni-based superalloy wire can be improved. Moreover, it was found that: therefore, it is effective to finish the Ni-based superalloy wire into a wire shape by strong plastic deformation.

That is, the present invention is a method for producing a Ni-based superalloy wire, including: a bar material preparation step of preparing a bar material of a Ni-based superalloy; and a bar material processing step of performing plastic working with a single working ratio of 40% or less from the circumferential surface of the bar material toward the axial center at a temperature of 500 ℃ or less a plurality of times until the cumulative working ratio becomes 60% or more, and reducing the cross-sectional area of the bar material. Further, the method for producing a Ni-based superalloy wire further includes, in addition to the above steps: and a heat treatment step of heat-treating the Ni-based superalloy wire obtained in the bar processing step at a temperature exceeding 500 ℃.

The wire diameter (diameter) of the Ni-based superalloy wire obtained by the production method of the present invention is, for example, preferably 10mm or less, and more preferably 6mm or less, 5mm or less, and 4mm or less, in order to adapt to various usage forms. Further, 3.5mm or less, 3mm or less, 2.5mm or less, and 2mm or less are more preferable. In order to improve the bending workability of such a Ni-based superalloy wire, if it is considered to eliminate the cast structure and to impart sufficient tensile strength to the Ni-based superalloy wire, it is effective to produce the Ni-based superalloy wire by the following production method: a material (rod material) having a cross-sectional area larger than that of the wire rod is prepared, and strong plastic working (that is, plastic working having a large working ratio) is performed thereon.

In this case, as means for enabling the above-described "strong plastic working", swaging working, drawing working using a die such as a box roll die or a hole die, and the like can be exemplified. The swaging is a processing method of forging the circumferential surface of the bar while rotating a plurality of dies surrounding the entire bar. This makes it possible to compress the cross-sectional area of the rod material while uniformly and uniformly applying pressure to the rod material, and therefore, this is an effective means for performing plastic working on a Ni-based superalloy that is considered to be difficult to perform plastic working while suppressing the occurrence of cracks and flaws.

In order to achieve the "strong plastic working", the method for producing the Ni-based superalloy wire of the present invention includes: the bar is subjected to plastic working at a high working ratio of "60% or more". The reduction ratio is preferably 70% or more, more preferably 80% or more. The working ratio is a cross-sectional area A of the bar (also referred to as "wire rod") before plastic working₀Cross-sectional area A of wire material after plastic working₁In the relation of (A)₀-A₁)/A₀]X 100 (%) formula. Further, the wire diameter of the Ni-based superalloy wire rod can be finished to be as small as, for example, 3.5mm or less, 3mm or less, 2.5mm or less, or 2mm or less, in accordance with the high reduction ratio. The upper limit of the working ratio of 60% or more is not particularly required. For example, the final wire diameter of the Ni-based superalloy wire rod to be produced may be set to less than 100%, 98%, or 95%.

The method for producing the Ni-based superalloy wire of the present invention is as follows: the plastic working at a reduction ratio of "60% or more" is further divided into a plurality of plastic working (so-called multi-pass). In the plastic working such as the swaging and die drawing, the number of "passes" may be counted as "1 pass" in the plastic working performed by one (or a pair of) dies or the like. It is important to reduce the single working ratio to "40% or less" in the plastic working divided into the plurality of times. That is, the plastic working (bar processing step) carried out in the present invention is "small-interval (stepwise) plastic working" in which plastic working is carried out a plurality of times with a single working ratio of 40% or less until the cumulative working ratio thereof becomes 60% or more. By plastic working of the small spaces, the cast structure of the Ni-based superalloy wire can be eliminated "throughout the entirety". Further, by reducing the single pass rate, the occurrence of flaws on the surface of the Ni-based superalloy wire rod can be further suppressed. The above-mentioned single pass plastic working at a small interval with a single pass working ratio of 30% or less is preferable.

The lower limit of the single pass reduction is not necessarily set. The lower limit thereof may be set to, for example, about 10% in terms of processing efficiency and the like. Alternatively, the working ratio may be 15% or more in one or two or more of the above-described plurality of times of plastic working.

Further, in the above-described multiple plastic working performed in the present invention, it is effective to set each plastic working temperature to a low temperature region in which recovery and recrystallization can be suppressed in order to impart tensile strength to the Ni-based superalloy wire finished into a final shape by completing all the passes of the multiple plastic working. In the present invention, the temperature is 500 ℃ or lower. Preferably 300 ℃ or lower, more preferably 100 ℃ or lower. Further preferably 50 ℃ or lower (e.g., room temperature). In contrast, in order to maintain the "plastic worked structure" and the "recrystallized structure" described below in the metallic structure of the Ni-based superalloy wire rod of the present invention, it is effective to set the plastic working temperature to a low temperature range in which recovery and recrystallization can be suppressed.

In the course of the above-mentioned multiple times of plastic working, it is not necessary to carry out heat treatment. The heat treatment here means a heat treatment in a high temperature region such as recovery or recrystallization, and is, for example, a heat treatment heated to a temperature exceeding 500 ℃. After the plastic working is completed a plurality of times, the heat treatment can be appropriately performed on the Ni-based superalloy wire finished into a final shape.

By the above method for producing the Ni-based superalloy wire, tensile strength can be imparted to the Ni-based superalloy wire. The tensile strength imparted to the Ni-based superalloy wire can be confirmed by the fact that the metallographic structure at this time is not a brittle "cast structure" but a "plastic worked structure" obtained by strong plastic deformation or a "recrystallized structure" obtained by subjecting the plastic worked structure to the above-described heat treatment. In addition, the above method for producing the Ni-based superalloy wire can adjust the metallographic structure of the Ni-based superalloy wire to the plastic worked structure or the recrystallized structure.

The "plastic worked structure" of the Ni-based superalloy wire rod of the present invention means, for example, a structure that is deformed in the plastic working direction thereof (that is, a structure that extends in the longitudinal direction of the wire rod) by strong plastic deformation. Such a Ni-based superalloy has a hardness of, for example, 500HV or more. In addition, for example, has a hardness of less than 700 HV. In addition, for example, in the Ni-based superalloy wire having a composition described later, the plastic worked structure can be specified by the presence of "collecting flow patterns" of γ' observed in the metallic structure. Fig. 1(a) is a photomicrograph obtained by observing a cross section including a central axis in a longitudinal direction of a structure of a Ni-based superalloy wire rod produced according to an example of the present invention. At this time, the left-right direction of fig. 1(a) (i.e., the direction of the arrow in the figure) is the longitudinal direction of the wire rod. In the scanning electron microscope image (hereinafter, referred to as "SEM image") at observation magnification of 5000 times in fig. 1(a), the portion (light-colored portion) visible in the collection of fine particulate dispersion is "γ'" (one large lump confirmed in the upper right is "carbide"). Further, it was confirmed that γ' was present as "flow-collecting streaks" along the longitudinal direction of the wire rod.

In the optical microscope image (hereinafter, referred to as "light microscopic image") at an observation magnification of 200 times in fig. 1 a, an aggregate (dark portion) in a substantially continuous band shape is "carbide". And it was confirmed that: the carbide is also present in the form of a "collecting flow" substantially parallel to the longitudinal direction of the wire. When a large amount of carbide exists in the metallographic structure, the plastic worked structure may be specified by the flow grain of the carbide.

The "recrystallized structure" of the Ni-based superalloy wire rod of the present invention is, for example, a structure in which crystal grains grow, which can be obtained by subjecting the plastic worked structure to a heat treatment or the like at a recrystallization temperature (e.g., a temperature exceeding 500 ℃). Fig. 1(b) is a photomicrograph obtained by observing a cross section including the central axis in the longitudinal direction of the structure of the Ni-based superalloy wire rod produced in the inventive example. The left-right direction of fig. 1(b) (i.e., the direction of the arrow in the figure) is the longitudinal direction of the wire rod. Fig. 1(b) shows a structure of the Ni-based superalloy wire shown in fig. 1(a) after heat treatment at a predetermined recrystallization temperature. In the light microscopic image at an observation magnification of 200 times in fig. 1(b), a substantially straight line clearly visible in the boundary between the different depths in the entire field of view is a "grain boundary". Further, it was confirmed that the unit surrounded by the grain boundary was "recrystallized grains". This grain boundary can also be confirmed by an SEM image of 5000 × observation magnification in fig. 1(b) (large lumps are "carbides").

In the case of the Ni-based superalloy wire of the present invention, the "having a recrystallized structure" may represent the size of the crystal grains. In the above case, the recrystallized structure may be expressed in the form of, for example, "having crystal grains with a maximum length of 100 μm or more" in the cross-sectional structure (the upper limit is about 1500 μm). In addition, such Ni-based superalloy has hardness of less than 500HV, for example. Further, the hardness is 400HV or more, for example.

Even in the case of the Ni-based super heat resistant alloy wire rod having the recrystallized structure, when a large amount of carbide is present in the metallic structure, the flow grains of the carbide can be confirmed in the grains or across the grain boundaries in the metallic structure (the microscopic image in fig. 1 (b)). Further, the metallurgical structure is "a structure obtained by subjecting the plastic worked structure to a heat treatment at a recrystallization temperature" based on the collective grain of the carbide. It is also known that the Ni-based superalloy wire having the recrystallized structure is formed into a wire shape by plastic working.

In the present invention, the brittle cast structure can be eliminated by adjusting the metallographic structure of the Ni-based superalloy wire to the "plastic worked structure or recrystallized structure" described above, and therefore, the wire is not easily broken even when bent, and the bending workability of the Ni-based superalloy wire can be improved. Further, the effect of improving the bending workability also depends on imparting tensile strength to the Ni-based superalloy wire. Therefore, in the case of the Ni-based superalloy wire of the present invention, the tensile strength imparted thereto may be represented by having the above-described plastic worked structure or recrystallized structure.

In addition, the Ni-based superalloy wire of the present invention is excellent in such bending workability, and is, for example, an Ni-based superalloy wire that does not break when a bending displacement reaches 50mm in a bending test by a cantilever beam as follows: "prepare a wire rod having a length of 150mm, restrain a position 25mm from one end of the wire rod, and apply a load to a position 25mm from the other end".

The Ni-based superalloy wire of the present invention is used by melting in, for example, repair or three-dimensional molding of a heat-resistant member. In the above case, the Ni-based superalloy wire is melted and then solidified, and if necessary, heat-treated after the solidification to complete the wire as a heat-resistant member. In order to maintain the heat resistance of the heat-resistant member and impart excellent bending workability to the wire rod before use, the Ni-based superalloy wire rod of the present invention (i.e., the rod material before plastic working) is preferably of a precipitation-strengthened type in which the equilibrium precipitation amount of γ' at 700 ℃. The equilibrium deposition amount of γ 'is a deposition amount of γ' which is stable in a thermodynamic equilibrium state. Further, the equilibrium precipitation amount of γ' at 700 ℃ is set to 35 mol% or more, whereby the heat resistance is effectively improved. More preferably 40 mol% or more, and still more preferably 50 mol% or more. Further, 60 mol% or more is particularly preferable. Further, it is preferably 63 mol% or more, further preferably 66 mol% or more, and further preferably 68 mol% or more. The upper limit of the value is not particularly required. However, about 75 mol% is realistic.

In the Ni-based superalloy of the present invention, the value indicating the equilibrium precipitation amount of γ' in "mol%" is a value that can be determined by the composition of the Ni-based superalloy. The value of "mol%" of the equilibrium precipitation amount can be determined by analysis based on thermodynamic equilibrium calculation. In the case of analysis based on thermodynamic equilibrium calculation, it can be determined with high accuracy and ease by using various thermodynamic equilibrium calculation software.

As the precipitation strengthening Ni-based superalloy having an equilibrium precipitation amount of γ 'at 700 ℃ of "35 mol% or more", for example, it is preferable to first adjust the precipitation strengthening Ni-based superalloy to a precipitation strengthening Ni-based superalloy having an equilibrium precipitation amount of γ' at 700 ℃ of, by mass%, C: 0-0.25%, Cr: 8.0-25.0%, Al: 0.5 to 8.0%, Ti: 0.4-7.0%, and the balance of Ni and impurities. The above-mentioned basic composition may further contain, as necessary, a component selected from the group consisting of Co: 0-28.0%, Mo: 0-8.0%, W: 0-6.0%, Nb: 0-4.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0-0.300% of 1 or more than 2 element species. The effects of the respective elements of the exemplified composition are described below (mass%, "%" for short).

＜C：0～0.25％＞

C has an effect of improving the strength of grain boundaries. However, if C is increased, coarse carbides increase, and ductility during plastic working deteriorates. Thus, the content of C is preferably 0.25% or less. More preferably 0.2% or less, still more preferably 0.1% or less, and still more preferably 0.05% or less. Particularly preferably 0.02% or less. The coarse carbide may be a starting point of tearing when the Ni-based superalloy wire is bent. Therefore, C is also preferably limited in improving the bending workability of the Ni-based superalloy wire. When C can be made to be at a non-additive level (impurity level of the raw material), the lower limit of C may be set to 0%.

On the other hand, the strength-improving effect by the C content acts to impart tensile strength to the Ni-based superalloy wire, and can contribute to improvement in bending workability of the Ni-based superalloy wire. In order to obtain this effect, the content of C is preferably 0.001% or more. More preferably 0.003% or more. More preferably 0.005% or more. Particularly preferably 0.01% or more.

＜Cr：8.0～25.0％＞

Cr is an element that improves oxidation resistance and corrosion resistance. However, if Cr is contained excessively, an brittle phase such as sigma (sigma) phase is formed, and hot workability in preparing a rod material, for example, is degraded. Thus, the content of Cr is preferably 8.0 to 25.0%.

＜Al：0.5～8.0％＞

Al is an element which forms gamma' and improves high-temperature strength. However, excessive Al content causes unstable metallographic structure of the heat-resistant member in a high-temperature state. Therefore, the Al content is preferably 0.5 to 8.0%.

＜Ti：0.4～7.0％＞

Like Al, Ti is an element that forms γ 'and strengthens γ' in a solid solution to improve high-temperature strength. However, if Ti is excessively contained, the metallographic structure of the heat-resistant member in a high-temperature state becomes unstable. Therefore, the content of Ti is preferably 0.4 to 7.0%.

The balance other than the elements described above is Ni, and it is needless to say that inevitable impurities may be contained. The basic composition may contain the following element types as necessary.

＜Co：0～28.0％＞

Co is one of the elements selected to improve the stability of the metallographic structure of the heat-resistant member. However, if Co becomes excessive, a brittle intermetallic compound of Co series is generated. Thus, Co is preferably contained at 28.0% or less as necessary. When Co can be made to be at a non-additive level (impurity level of the raw material), the lower limit of Co can be set to 0%.

＜Mo：0～8.0％＞

Mo is one of the selection elements which are beneficial to the solid solution strengthening of the matrix and the improvement of high-temperature strength. However, if Mo is excessive, an intermetallic compound phase is formed, and the high-temperature strength is deteriorated. Thus, Mo is preferably contained by 8.0% or less as necessary. When Mo can be made to be at a non-additive level (impurity level of the raw material), the lower limit of Mo may be set to 0%.

＜W：0～6.0％＞

W is one of the elements which is advantageous for solid solution strengthening of the matrix, similarly to Mo. On the other hand, if W is excessive, a harmful intermetallic compound phase is formed, and the high-temperature strength is deteriorated. Accordingly, W is preferably contained at 6.0% or less as necessary. When W may be at a non-additive level (impurity level of the raw material), the lower limit of W may be set to 0%.

＜Nb：0～4.0％＞

Nb is one of the elements selected to form γ 'and strengthen γ' in solid solution to improve high-temperature strength, similarly to Al and Ti. However, excessive inclusion of Nb results in formation of a harmful delta phase, which hinders the effect of improving the high-temperature strength by Ti. Thus, Nb is preferably contained at 4.0% or less as necessary. When Nb can be made to be at a non-additive level (impurity level of the raw material), the lower limit of Nb may be set to 0%.

＜Ta：0～3.0％＞

Ta is one of the elements selected to form γ 'and to strengthen γ' in a solid solution manner to improve high-temperature strength, similarly to Al and Ti. However, if Ta is excessively contained, γ' becomes unstable at high temperature, and it becomes difficult to obtain the effect of improving the high-temperature strength inherent in Ta. Thus, Ta is preferably contained at 3.0% or less as necessary. More preferably 2.5% or less, still more preferably 2.25% or less, still more preferably 2.0% or less, and particularly preferably 1.75% or less. When Ta can be made to be at a non-additive level (impurity level of the raw material), the lower limit of Ta may be set to 0%.

When the above-described effects by Ta being contained are obtained, the content is preferably 0.3% or more, more preferably 0.6% or more, further preferably 0.9% or more, and further preferably 1.1% or more.

＜Fe：0～10.0％＞

Fe is one of the elements that can be contained in place of expensive Ni and Co and is effective for reducing the cost of the alloy. However, if Fe is contained excessively, an brittle phase such as σ phase is formed, and hot workability in preparing a rod material, for example, is degraded. Thus, Fe is preferably contained by 10.0% or less as necessary. More preferably 8.0% or less, still more preferably 5.0% or less, and still more preferably 2.0% or less. When Fe can be made to be at a non-additive level (impurity level of the raw material), the lower limit of Fe may be set to 0%.

When the above-described effects by Fe are obtained, the content is preferably 0.1% or more, more preferably 0.4% or more, still more preferably 0.6% or more, and still more preferably 0.8% or more.

＜V：0～1.2％＞

V is one of the selective elements useful for solid solution strengthening of the matrix and grain boundary strengthening by carbide formation. However, if V is too large, unstable intermetallic compounds are formed in the metallographic structure, and the high-temperature strength is lowered. Thus, V is preferably contained at 1.2% or less as necessary. More preferably 1.0% or less, still more preferably 0.8% or less, and still more preferably 0.7% or less. When V can be made to be at a non-additive level (impurity level of the raw material), the lower limit of V may be set to 0%.

When the above-described effect by V is obtained, it is preferably 0.1% or more, more preferably 0.2% or more, further preferably 0.3% or more, and further preferably 0.5% or more.

＜Hf：0～1.0％＞

Hf is one of the selective elements useful for improving the oxidation resistance of the alloy and strengthening the grain boundary by carbide formation. However, if the amount of Hf is too large, it will cause the formation of oxides during the production process and the formation of high-temperature unstable phases, which will adversely affect the manufacturability and high-temperature mechanical properties. Thus, Hf is preferably contained at 1.0% or less as necessary. More preferably 0.7% or less, still more preferably 0.5% or less, and still more preferably 0.3% or less. When Hf may be made to be at a non-additive level (impurity level of the raw material), the lower limit of Hf may be set to 0%.

When the above-described effects by Hf being contained are obtained, the content is preferably 0.02% or more, more preferably 0.05% or more, still more preferably 0.1% or more, and still more preferably 0.15% or more.

＜B：0～0.300％＞

B is one of the elements selected for improving grain boundary strength, creep strength and ductility. However, if B is too large, the melting point of the alloy is greatly lowered, and the high-temperature strength is adversely affected. Thus, B is preferably contained at 0.300% or less as necessary. More preferably 0.200% or less, still more preferably 0.100% or less, still more preferably 0.050% or less, and particularly preferably 0.020% or less. When B may be at a non-additive level (impurity level of the raw material), the lower limit of B may be set to 0%.

When the above-described effects by the inclusion of B are obtained, the content is preferably 0.002% or more, more preferably 0.003% or more, still more preferably 0.004% or more, and still more preferably 0.005% or more.

＜Zr：0～0.300％＞

Like B, Zr is one of selective elements having an effect of improving grain boundary strength. However, if Zr is too large, the melting point of the alloy is greatly lowered, and the high-temperature strength is adversely affected. Thus, Zr is preferably contained at 0.300% or less as necessary. When Zr can be made to be a non-additive level (impurity level of the raw material), the lower limit of Zr may be set to 0%.

In the above-described basic component composition, for example, the composition is composed of, in mass%, C: 0-0.2%, Cr: 8.0-22.0%, Al: 2.0-8.0%, Ti: 0.4 to 7.0%, Co: 0-28.0%, Mo: 2.0-7.0%, W: 0-6.0%, Nb: 0-4.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: the balance precipitation amount of γ' at 700 ℃ is high (for example, 40 mol% or more) in the composition A of 0 to 0.300% and the balance of Ni and impurities, and it is preferable to improve the heat resistance of the Ni-based superalloy.

In the case of the above-mentioned composition a, 1 or 2 or more of the elements are more preferably in the following ranges.

< Cr > for the lower limit, preferably 9.0%, more preferably 9.5%. The upper limit is preferably 18.0%, more preferably 16.0%, and still more preferably 14.0%.

< Al > for the lower limit, 2.5% is preferable, 3.5% is more preferable, and 4.5% is further preferable. The upper limit is preferably 7.5%, more preferably 7.0%, and still more preferably 6.5%.

< Ti > for the lower limit, preferably 0.45%, more preferably 0.50%. The upper limit is preferably 5.0%, more preferably 3.0%, and still more preferably 1.0%.

< Co > for the lower limit, 1.0%, more preferably 3.0%, further preferably 8.0%, further preferably 10.0%. The upper limit is preferably 18.0%, more preferably 16.0%, and still more preferably 13.0%.

< Mo > for the lower limit, 2.5% is preferable, 3.0% is more preferable, and 3.5% is further preferable. The upper limit is preferably 6.0%, more preferably 5.5%, and still more preferably 5.0%.

< W > for the lower limit, preferably 0.8%, more preferably 1.0%. The upper limit is preferably 5.5%, more preferably 5.0%, and still more preferably 4.5%.

< Nb > for the lower limit, 0.5% is preferable, 1.0% is more preferable, 1.5% is further preferable, and 2.0% is further preferable. The upper limit is preferably 3.5%, more preferably 3.0%, and still more preferably 2.5%.

< Zr > for the lower limit, 0.001%, more preferably 0.005%, still more preferably 0.010%, still more preferably 0.030% is preferable. The upper limit is preferably 0.250%, more preferably 0.200%, and still more preferably 0.150%.

In addition, the above-mentioned basic component composition is composed of, for example, C: 0-0.2%, Cr: 20.0 to 25.0%, Al: 0.5 to 5.0%, Ti: 1.0-6.0%, Co: 10.0 to 28.0%, Mo: 0-8.0%, W: 0.5 to 5.0%, Nb: 0.1 to 3.0%, Ta: 0-3.0%, Fe: 0-10.0%, V: 0-1.2%, Hf: 0-1.0%, B: 0-0.300%, Zr: 0.010 to 0.300% and the balance of Ni and impurities, and the balance of Ni and impurities. Therefore, the Ni-based superalloy wire rod of the present invention is preferably also made of the above composition, in terms of being usable for repair and production of a conventional heat-resistant member.

In the case of the above-mentioned composition B, 1 or 2 or more of the elements are more preferably in the following range.

< Cr > for the lower limit, 20.5% is preferable, 21.0% is more preferable, and 21.5% is further preferable. The upper limit is preferably 24.5%, more preferably 24.0%, and still more preferably 23.5%.

< Al > for the lower limit, 0.8% is preferable, 1.0% is more preferable, 1.25% is further preferable, and 1.5% is still further preferable. The upper limit is preferably 4.0%, more preferably 3.5%, further preferably 3.0%, and further preferably 2.5%.

< Ti > for the lower limit, 1.5%, more preferably 2.0%, further preferably 2.5%, further preferably 3.0%. The upper limit is preferably 5.5%, more preferably 5.0%, still more preferably 4.5%, and still more preferably 4.2%.

< Co > for the lower limit, 12.0% is preferable, 14.0% is more preferable, 16.0% is further preferable, and 17.0% is still further preferable. The upper limit is preferably 27.0%, more preferably 25.0%, still more preferably 23.0%, and still more preferably 21.0%.

< Mo > for the lower limit, 0.1% is preferable, 0.3% is more preferable, 0.5% is further preferable, and 0.7% is still further preferable. The upper limit is preferably 5.0%, more preferably 3.0%, and still more preferably 1.0%.

< W > for the lower limit, preferably 0.7%, more preferably 1.2%, further preferably 1.5%, further preferably 1.7%. The upper limit is preferably 4.5%, more preferably 4.0%, further preferably 3.5%, and further preferably 3.0%.

< Nb > for the lower limit, 0.2% is preferable, 0.3% is more preferable, 0.5% is further preferable, and 0.7% is still further preferable. For the upper limit, 2.5%, more preferably 2.25%, still more preferably 2.00%, still more preferably 1.50% is preferable.

< Zr > for the lower limit, 0.020% is preferable, 0.030% is more preferable, 0.050% is further preferable, and 0.070% is further preferable. The upper limit is preferably 0.250%, more preferably 0.200%, still more preferably 0.170%, and still more preferably 0.150%.

According to the present invention, a method for producing a Ni-based superalloy wire rod having excellent bending workability and a Ni-based superalloy wire rod can be provided. Thus, for example, in the bar processing step of the present invention, the cross-sectional area of the bar is reduced to the final wire diameter by performing all the predetermined passes, and the Ni-based superalloy wire excellent in bending workability can be provided as a "product". Further, such a Ni-based superalloy wire rod may be formed into a coil shape.