WO2018193810A1

WO2018193810A1 - High strength and low thermal expansion alloy wire

Info

Publication number: WO2018193810A1
Application number: PCT/JP2018/013316
Authority: WO
Inventors: 孝細田; 中間　一夫; 知哉松岡; 美里草刈
Original assignee: 山陽特殊製鋼株式会社; 住友電気工業株式会社
Priority date: 2017-04-19
Filing date: 2018-03-29
Publication date: 2018-10-25
Also published as: KR102509847B1; CN110546292A; CN110546292B; JP6812461B2; JPWO2018193810A1; KR20200003794A

Abstract

The purpose of the present invention is to provide an alloy wire having properties required of high strength and low thermal expansion alloy wires, wherein a wide range of conditions can be used for heat treatment when manufacturing the alloy wire to obtain a desired hardness. In order to achieve the purpose, there is provided a high strength and low thermal expansion alloy wire having a predetermined alloy composition and having grains in which a (Mo,V)C-based composite carbide is present, wherein the value of ([Mo]+2.8[V])/[C] is 9.6-21.7 and the value of {Mo}/{V} is 2.0-4.0, [Mo], [V], and [C] being, respectively, the amounts of Mo, V, and C contained in the alloy wire, {Mo} and {V} being, respectively, the amounts of Mo and V contained in the (Mo,V)C-based composite carbide.

Description

High strength low thermal expansion alloy wire

Cross-reference of related applications

This application claims priority based on Japanese Patent Application No. 2017-083035 filed on Apr. 19, 2017, the entire disclosure of which is incorporated herein by reference.

In the present invention, it is desired to avoid changes in size and shape due to thermal expansion. However, the present invention can be used for core materials for low-slack power transmission lines, wires for precision mechanical parts, etc. that may increase in temperature during use. The present invention relates to a high strength low thermal expansion alloy wire and a high strength low thermal expansion coated alloy wire.

Conventionally, various high-strength low thermal expansion alloy wires are known. For example, in Patent Document 1 (Japanese Patent Laid-Open No. 7-228947), by weight ratio, C: 0.1 to 0.4%, Si: 0.2 to 1.5%, Mn: 0.1 to 1.5%, Ni: 33-42%, Co: 5.0% or less, Cr: 0.75-3.0%, V: 0.2-3.0%, B: 0.003% or less, O: 0.003% or less, Al: 0.1% or less, Mg: 0.1% or less, Ti: 0.1% or less, Ca: 0.1% or less, and the balance from Fe and inevitable impurities And a high-strength, low-thermal-expansion alloy wire characterized by having a relationship of 1.0% ≦ V + Cr ≦ 5.0%.

In Patent Document 2 (Japanese Patent Laid-Open No. 2002-256395), C: 0.1 to 0.4%, V: more than 0.5% to 3.0%, and Ni: 25 to 50% by mass. A high-strength, low-thermal-expansion alloy wire excellent in twisting characteristics, characterized in that it contains 2%, satisfies 2 ≦ V / C ≦ 9, and consists of the balance Fe and inevitable impurities. In Patent Document 2, the high-strength low thermal expansion alloy wire contains one or more of Al, Mo, Ti, Nb, Ta, Zr, Hf, W, and Cu in a total amount of 5% or less. It is disclosed that

Patent Document 3 (Japanese Patent Application Laid-Open No. 2003-82439) discloses that by weight, C: 0.20 to 0.40%, Si: ≦ 0.8%, Mn: ≦ 1.0%, P: ≦ 0.050%, S: ≦ 0.015%, Cu: ≦ 1.0%, Ni: 35-40%, Cr: ≦ 0.5%, Mo: 1.5-6.0%, V: 0.05 to 1.0%, O: ≦ 0.015%, N: ≦ 0.03%, Mo / V ≧ 1.0 and (0.3Mo + V) ≧ 4C, and the balance Fe And the average coefficient of linear thermal expansion from 20 to 230 ° C. and from 230 to 290 ° C. is 3.7 × 10 ⁻⁶ or less and 10.8 × 10 ⁻⁶ or less, respectively. An Invar alloy wire excellent in strength and twisting characteristics, which is characterized by being, has been disclosed.

JP-A-7-228947 JP 2002-256395 A JP 2003-82439 A

Conventional high strength and low thermal expansion alloy wires as disclosed in Patent Documents 1 to 3 are hardened by precipitation hardening by aging heat treatment, but the optimum conditions for aging heat treatment (temperature and holding time of the temperature) ) Range, for example, the optimum range for obtaining the maximum hardness is narrow, and it is difficult to obtain the desired hardness.

Therefore, the present invention is an alloy wire having characteristics (for example, high strength, high twist value, good ductility, low coefficient of thermal expansion, etc.) necessary as a high strength low thermal expansion alloy wire, An object of the present invention is to provide an alloy wire capable of using a wide range of conditions for heat treatment to obtain a desired hardness.

By appropriately controlling the composition of the alloy wire, the composition of the carbides present in the crystal grains, the dispersion state of the carbides present in the crystal grains, the present inventors have obtained the characteristics necessary as a high-strength low thermal expansion alloy wire. (For example, high strength, high twist value, good ductility, low coefficient of thermal expansion, etc.) When manufacturing alloy wires, a wide range of conditions can be used for heat treatment to obtain the desired hardness As a result, the present inventors have found that an alloy wire can be realized.

The present invention provides the following high-strength low thermal expansion alloy wires and high-strength low thermal expansion coated alloy wires.
(1) By mass%, C: 0.1% to 0.4%, Si: 0.1% to 2.0%, Mn: more than 0% to 2.0%, Ni: 25% to 40% %: V: 0.5% to 3.0%, Mo: 0.4% to 1.9%, Cr: 0% to 3.0%, Co: 0% to 3.0% B: 0% to 0.05%, Ca: 0% to 0.05%, Mg: 0% to 0.05%, Al: 0% to 1.5%, Ti: 0% or more 1.5% or less, Nb: 0% to 1.5%, Zr: 0% to 1.5%, Hf: 0% to 1.5%, Ta: 0% to 1.5%, W: 0% to 1.5%, Cu: 0% to 1.5%, O: 0% to 0.005%, and N: 0% to 0.03%, the balance being Fe High and inevitable impurities Every time a low thermal expansion alloy wire,
In the alloy wire crystal grains, there is a (Mo, V) C-based composite carbide containing both Mo and V.
When the amounts of Mo, V and C contained in the alloy wire are [Mo], [V] and [C], respectively, the value of ([Mo] +2.8 [V]) / [C] is 9. 6 to 21.7,
When the amount of Mo and V contained in the (Mo, V) C-based composite carbide is {Mo} and {V}, respectively, the value of {Mo} / {V} is 0.2 or more and 4.0 or less. The high strength low thermal expansion alloy wire.
(2) In the crystal grains, the density of the (Mo, V) C-based composite carbide is 10 pieces / μm ² or more, and the diameter is 150 nm or less with respect to the total number of the (Mo, V) C-based composite carbides. The high-strength, low-thermal-expansion alloy wire according to (1), wherein a ratio of the number of the (Mo, V) C-based composite carbide is 50% or more.
(3) By mass%, Cr: more than 0%, including 3.0% or less,
When the amounts of Mo, V and Cr contained in the alloy wire are [Mo], [V] and [Cr], respectively, the value of ([Mo] + [V]) / [Cr] is 1.2 or more. The high-strength low thermal expansion alloy wire according to (1) or (2).
(4) By mass%, Co: more than 0%, including 3.0% or less,
Any one of (1) to (3), wherein [Co] + [Ni] is 35% or more and 40% or less when the amounts of Co and Ni contained in the alloy wire are [Co] and [Ni], respectively. A high-strength, low-thermal-expansion alloy wire according to claim 1.
(5) By mass%, B: more than 0% 0.05% or less, Ca: more than 0% 0.05% or less, and Mg: more than 0% 0.05% or less The high-strength low thermal expansion alloy wire according to any one of (1) to (4), comprising:
(6) In mass%, Al: more than 0% and 1.5% or less, Ti: more than 0% and 1.5% or less, Nb: more than 0% and 1.5% or less, Zr: more than 0% and 1.5% or less Hf: more than 0% and 1.5% or less, Ta: more than 0% and 1.5% or less, W: more than 0% and 1.5% or less, and Cu: more than 0% and 1.5% or less The high-strength low-thermal-expansion alloy wire according to any one of (1) to (5), comprising seeds or two or more kinds.
(7) The high-strength, low-thermal-expansion alloy wire according to any one of (1) to (6), which includes N: more than 0% and 0.03% or less by mass%.
(8) The high-strength low thermal expansion alloy wire according to any one of (1) to (7), which has a tensile strength of 1400 MPa or more.
(9) The high strength and low thermal expansion according to any one of (1) to (8), wherein the twist value measured at a distance between the gauge points 100 times the final wire diameter of the alloy wire is 20 times or more. Alloy wire.
(10) The high strength and low thermal expansion alloy wire according to any one of (1) to (9), wherein the elongation is 0.8% or more.
(11) Average linear thermal expansion coefficient between two points from 15 ° C. to 100 ° C. is 3 × 10 ⁻⁶ / ° C. or less (15 to 100 ° C.), average linear thermal expansion between two points from 15 ° C. to 230 ° C. A coefficient of 4 × 10 ⁻⁶ / ° C. or less (15 to 230 ° C.), an average linear thermal expansion coefficient between two points from 100 ° C. to 240 ° C. of 4 × 10 ⁻⁶ / ° C. or less (100 to 240 ° C.), and The high strength according to any one of (1) to (10), wherein an average linear thermal expansion coefficient between two points from 230 ° C. to 290 ° C. is 11 × 10 ⁻⁶ / ° C. or less (230 to 290 ° C.) Low thermal expansion alloy wire.
(12) A high-strength and low-heat comprising the high-strength low-thermal expansion alloy wire according to any one of (1) to (11) and an Al coating layer or a Zn coating layer formed on the surface of the high-strength low-thermal expansion alloy wire Expanded coated alloy wire.

According to the present invention, an alloy wire having characteristics necessary for a high-strength low thermal expansion alloy wire (for example, high strength, high twist value, good ductility, low thermal expansion coefficient, etc.) Alloy wires and coated alloy wires are provided that can be used in a wide range of conditions for heat treatment to obtain the desired hardness. The alloy wire and the coated alloy wire of the present invention are desired to avoid dimensional and shape changes due to thermal expansion. However, there is a possibility that the temperature rises during use. It is useful as a high-strength, low-thermal expansion alloy wire used in

Fig. 1 shows an example of a curve in which the horizontal axis is the aging temperature and the vertical axis is the tensile strength when aging heat treatment is performed with the heating time fixed at 6 hours and the heating temperature varied between 610 and 650 ° C. FIG. FIG. 2 shows a curve in which the horizontal axis is the aging temperature and the vertical axis is the tensile strength when the heating temperature is fixed at 650 ° C. and the heating time is changed between 30 minutes and 9 hours. It is a conceptual diagram which shows an example.

<Composition of alloy wire>
Hereinafter, the composition of the alloy wire of the present invention will be described. In the present specification, “%” means mass% unless otherwise specified.

C: 0.1% or more and 0.4% or less C is an essential element of the alloy wire of the present invention. C is effective for strengthening solid solution, precipitation hardening due to carbide formation, and strengthening thereof. From the viewpoint of effectively exhibiting such C effects, the C content is adjusted to 0.1% or more, preferably 0.13% or more, and more preferably 0.15% or more. On the other hand, when the content of C is excessive, ductility is lowered and the linear thermal expansion coefficient is increased. Therefore, the C content is adjusted to 0.4% or less, preferably 0.38% or less, and more preferably 0.36% or less.

Si: 0.1% or more and 2.0% or less Si is an essential element of the alloy wire of the present invention. Si is effective for strengthening solid solution. From the viewpoint of effectively exhibiting the effect of Si, the Si content is adjusted to 0.1% or more, preferably 0.2% or more, and more preferably 0.3% or more. On the other hand, if the Si content is excessive, the linear thermal expansion coefficient increases. Accordingly, the Si content is adjusted to 2.0% or less, preferably 1.7% or less, and more preferably 1.3% or less.

Mn: more than 0% and not more than 2.0% Mn is an essential element of the alloy wire of the present invention. Mn acts as a deoxidizer and is effective for strengthening solid solution. From the viewpoint of effectively exhibiting such an effect of Mn, the content of Mn is adjusted to more than 0%, preferably 0.1% or more, and more preferably 0.2% or more. On the other hand, if the Mn content is excessive, the linear thermal expansion coefficient increases. Therefore, the Mn content is adjusted to 2.0% or less, preferably 1.8% or less, and more preferably 1.3% or less.

Ni: 25% or more and 40% or less Ni is an essential element of the alloy wire of the present invention. Ni is effective for realizing a low linear thermal expansion coefficient. From the viewpoint of effectively exhibiting such an effect of Ni, the Ni content is adjusted to 25% or more, preferably 30% or more, and more preferably 34% or more. On the other hand, if the Ni content is excessive, it is difficult to achieve a low linear thermal expansion coefficient, and the alloy wire cost increases. Therefore, the Ni content is adjusted to 40% or less, preferably 39% or less, and more preferably 38% or less.

V: 0.5% to 3.0% V is an essential element of the alloy wire of the present invention. V is effective for precipitation hardening due to carbide formation and its strengthening, and is effective for avoiding ductile deterioration through suppressing coarsening of carbides in crystal grains and promoting fine precipitation of carbides in crystal grains. From the viewpoint of effectively exhibiting such V effects, the V content is adjusted to 0.5% or more, preferably 0.6% or more, and more preferably 0.7% or more. On the other hand, if the content of V is excessive, the above effect is saturated, an increase in the effect commensurate with the increase in content cannot be obtained, and the linear thermal expansion coefficient increases. Therefore, the content of V is adjusted to 3.0% or less, preferably 2.8% or less, and more preferably 2.6% or less.

Mo: 0.4% or more and 1.9% or less Mo is an essential element of the alloy wire of the present invention. Mo is effective for precipitation hardening by carbide formation and its strengthening, and is effective for preventing ductility deterioration through suppressing coarsening of carbides in crystal grains and promoting fine precipitation of carbides in crystal grains. From the viewpoint of effectively exhibiting such an effect of Mo, the Mo content is adjusted to 0.4% or more, preferably 0.5% or more, and more preferably 0.7% or more. On the other hand, when the content of Mo is excessive, the above effect is saturated, an increase in the effect commensurate with the increase in content cannot be obtained, and the linear thermal expansion coefficient increases. Therefore, the Mo content is adjusted to 1.9% or less, preferably 1.7% or less, and more preferably 1.5% or less.

([Mo] +2.8 [V]) / [C] Value When the amounts of Mo, V and C contained in the alloy wire of the present invention are [Mo], [V] and [C], respectively ( The value of [Mo] +2.8 [V]) / [C] is not less than 9.6 and not more than 21.7. When the value of ([Mo] +2.8 [V]) / [C] is less than 9.6, the C content becomes relatively excessive and ductility is lowered. Therefore, the value of ([Mo] +2.8 [V]) / [C] is adjusted to 9.6 or more, preferably 10.0 or more, and more preferably 10.8 or more. When the value of ([Mo] +2.8 [V]) / [C] is 9.6 or more, precipitation hardening by carbide formation and its strengthening can be realized, and ductility can be optimized. On the other hand, when the value of ([Mo] +2.8 [V]) / [C] exceeds 21.7, the V content and the Mo content become relatively excessive, and the effects of V and Mo are saturated. However, an increase in effect commensurate with the increase in content cannot be obtained, and the linear thermal expansion coefficient increases. Therefore, the value of ([Mo] +2.8 [V]) / [C] is adjusted to 21.7 or less, preferably 21.3 or less, and more preferably 21.0 or less.

The alloy wire of the present invention contains the above essential elements, and the balance consists of Fe and unavoidable impurities, but can contain one or more of the following optional elements and impurities as necessary.

Cr: 0% to 3.0% Cr is an optional element of the alloy wire of the present invention. Cr is effective for strengthening solid solution. When it is desired to effectively exhibit such an effect of Cr, the Cr content is adjusted to more than 0%, preferably 0.1% or more, more preferably 0.3% or more. On the other hand, when the content of Cr is excessive, the formation of coarse carbides decreases the strength and ductility, and increases the linear thermal expansion coefficient. Therefore, the Cr content is adjusted to 3.0% or less, preferably 2.5% or less, and more preferably 2.0% or less.

When the amounts of Mo, V and Cr contained in the alloy wire of the present invention are [Mo], [V] and [Cr], respectively, the value of ([Mo] + [V]) / [Cr] is preferably Is 1.2 or more. When the value of ([Mo] + [V]) / [Cr] is less than 1.2, the Cr content becomes relatively excessive, and precipitation hardening is hindered by the formation of coarse carbides, and ductility. Decreases. Therefore, the value of ([Mo] + [V]) / [Cr] is adjusted to 1.2 or more, preferably 1.3 or more, and more preferably 1.5 or more. The upper limit of the value of ([Mo] + [V]) / [Cr] is not particularly limited, but is preferably 8.0 or less, more preferably 6.0 or less.

Co: 0% to 3.0% Co is an optional element of the alloy wire of the present invention. Co has the same effect as Ni and is effective in stabilizing the linear thermal expansion coefficient due to an increase in the Curie point. When it is desired to effectively exhibit such an effect of Co, the Co content is adjusted to more than 0%, preferably 0.1% or more, and more preferably 0.3% or more. On the other hand, if the Co content is excessive, the alloy wire cost increases and the linear thermal expansion coefficient increases. Therefore, the Co content is adjusted to 3.0 or less, preferably 2.8 or less, and more preferably 2.5% or less.

[Co] + [Ni] is preferably 35% or more and 40% or less, when the amounts of Co and Ni contained in the alloy wire of the present invention are [Co] and [Ni], respectively. When [Co] + [Ni] is less than 35%, it is difficult to realize a low linear thermal expansion coefficient. Therefore, [Co] + [Ni] is adjusted to preferably 35% or more, more preferably 36% or more, and still more preferably 37% or more. When [Co] + [Ni] is 35% or more, a low linear thermal expansion coefficient can be realized. On the other hand, when [Co] + [Ni] exceeds 40%, it is difficult to realize a low coefficient of linear thermal expansion, and the alloy wire cost increases. Therefore, [Co] + [Ni] is adjusted to preferably 40% or less, more preferably 39.5% or less, and still more preferably 39% or less.

B: 0% to 0.05% B is an optional element of the alloy wire of the present invention. B is effective for improving hot workability by strengthening grain boundaries and strengthening resistance to grain boundary oxidation. When it is desired to effectively exhibit such an effect of B, the B content is adjusted to more than 0%, preferably 0.001% or more, more preferably 0.002% or more. On the other hand, when the content of B is excessive, hot workability is lowered. Therefore, the B content is adjusted to 0.05% or less, preferably 0.03% or less, and more preferably 0.01% or less.

Ca: 0% to 0.05% Ca is an optional element of the alloy wire of the present invention. Ca is effective in improving hot workability by S fixation. When it is desired to effectively exhibit such an effect of Ca, the Ca content is adjusted to more than 0%, preferably 0.005% or more, and more preferably 0.01% or more. On the other hand, when the content of Ca is excessive, hot workability is lowered. Therefore, the Ca content is adjusted to 0.05% or less, preferably 0.04% or less, and more preferably 0.03% or less.

Mg: 0% to 0.05% Mg is an optional element of the alloy wire of the present invention. Mg is effective in improving hot workability by S fixation. When it is desired to effectively exhibit such an effect of Mg, the content of Mg is adjusted to more than 0%, preferably 0.01% or more, more preferably 0.015% or more. On the other hand, when the content of Mg is excessive, hot workability is lowered. Therefore, the Mg content is adjusted to 0.05% or less, preferably 0.045% or less, and more preferably% 0.04 or less.

Al: 0% to 1.5% Al is an optional element of the alloy wire of the present invention. Al is effective for removal of oxide inclusions due to the deoxidation effect, strengthening of solid solution, precipitation hardening, and strengthening thereof. When it is desired to effectively exhibit such an effect of Al, the Al content is adjusted to more than 0%, preferably 0.005% or more, and more preferably 0.01% or more. On the other hand, when the content of Al is excessive, the ductility is lowered, the thermal expansion coefficient is increased, and the alloy wire cost is increased. Therefore, the Al content is adjusted to 1.5% or less, preferably 1.3% or less, and more preferably 1.0% or less.

Ti: 0% or more and 1.5% or less Ti is an optional element of the alloy wire of the present invention. Ti is effective for precipitation hardening and strengthening thereof, and can be used as an alternative element for V or Mo. When it is desired to effectively exhibit the effect of Ti, the Ti content is adjusted to more than 0%, preferably 0.001% or more, and more preferably 0.005% or more. On the other hand, when the content of Ti is excessive, a decrease in age hardening ability, a decrease in ductility, an increase in thermal expansion coefficient, and an increase in alloy wire cost occur. Therefore, the Ti content is adjusted to 1.5% or less, preferably 1.3% or less, and more preferably 1.0% or less.

Nb: 0% to 1.5% Nb is an optional element of the alloy wire of the present invention. Nb is effective for precipitation hardening and strengthening thereof, and can be used as an alternative element for V or Mo. When it is desired to effectively exhibit such an effect of Nb, the content of Nb is adjusted to more than 0%, preferably 0.01% or more, more preferably 0.02% or more. On the other hand, when the content of Nb is excessive, a decrease in age hardening ability, a decrease in ductility, an increase in thermal expansion coefficient, and an increase in alloy wire cost occur. Therefore, the Nb content is adjusted to 1.5% or less, preferably 1.3% or less, and more preferably 1.0% or less.

Zr: 0% to 1.5% Zr is an optional element of the alloy wire of the present invention. Zr is effective for precipitation hardening and strengthening thereof, and can be used as an alternative element for V or Mo. When it is desired to effectively exhibit such Zr effects, the Zr content is adjusted to be more than 0%, preferably 0.01% or more, more preferably 0.02% or more. On the other hand, when the content of Zr is excessive, a decrease in age hardening ability, a decrease in ductility, an increase in thermal expansion coefficient, and an increase in alloy wire cost occur. Therefore, the Zr content is adjusted to 1.5% or less, preferably 1.3% or less, and more preferably 1.0% or less.

Hf: 0% to 1.5% Hf is an optional element of the alloy wire of the present invention. Hf is effective for precipitation hardening and strengthening thereof, and can be used as an alternative element for V or Mo. When it is desired to effectively exhibit such an effect of Hf, the content of Hf is adjusted to more than 0%, preferably 0.01% or more, more preferably 0.02% or more. On the other hand, when the content of Hf is excessive, a decrease in age hardening ability, a decrease in ductility, an increase in thermal expansion coefficient, and an increase in alloy wire cost occur. Therefore, the content of Hf is adjusted to 1.5% or less, preferably 1.4% or less, and more preferably 1.3% or less.

Ta: 0% to 1.5% Ta is an optional element of the alloy wire of the present invention. Ta is effective for precipitation hardening and strengthening thereof, and can be used as an alternative element for V or Mo. When it is desired to effectively exhibit such an effect of Ta, the content of Ta is adjusted to more than 0%, preferably 0.01% or more, more preferably 0.02% or more. On the other hand, when the content of Ta is excessive, a decrease in age hardening ability, a decrease in ductility, an increase in thermal expansion coefficient, and an increase in alloy wire cost occur. Therefore, the Ta content is adjusted to 1.5% or less, preferably 1.4% or less, and more preferably 1.3% or less.

W: 0% to 1.5% W is an optional element of the alloy wire of the present invention. W is effective for precipitation hardening and strengthening thereof, and can be used as an alternative element for V or Mo. When it is desired to effectively exhibit such an effect of W, the W content is adjusted to more than 0%, preferably 0.01% or more, more preferably 0.02% or more. On the other hand, when the content of W is excessive, a decrease in age hardening ability, a decrease in ductility, an increase in thermal expansion coefficient, and an increase in alloy wire cost occur. Therefore, the W content is adjusted to 1.5% or less, preferably 1.4% or less, and more preferably 1.3% or less.

Cu: 0% to 1.5% Cu is an optional element of the alloy wire of the present invention. Cu is effective for precipitation hardening and its strengthening by forming Cu particles and raises the Curie point. When it is desired to effectively exhibit such an effect of Cu, the Cu content is adjusted to more than 0%, preferably 0.01% or more, more preferably 0.02% or more. On the other hand, when the Cu content is excessive, the hot workability is lowered and the alloy wire cost is increased. Therefore, the Cu content is adjusted to 1.5% or less, preferably 1.3% or less, and more preferably 1.0% or less.

O: 0% or more and 0.005% or less O is an impurity of the alloy wire of the present invention. O reduces ductility due to oxide formation. Therefore, the content of O is adjusted to 0.005% or less, preferably 0.003% or less, and more preferably 0.001% or less.

N: 0% or more and 0.03% or less N is an optional element of the alloy wire of the present invention. N has the same effects as C, such as solid solution strengthening. When it is desired to effectively exhibit such an effect of N, the N content is adjusted to more than 0%, preferably 0.01% or more. On the other hand, if the content of N is excessive, ductility is reduced due to nitride formation. Therefore, the N content is adjusted to 0.03% or less, preferably 0.025% or less.

The alloy wire according to an embodiment of the present invention includes B: more than 0% and less than 0.05%, Ca: more than 0% and less than 0.05%, and Mg: more than 0% and less than 0.05%. Includes seeds or two or more.

The alloy wire according to another embodiment of the present invention includes Al: more than 0% and 1.5% or less, Ti: more than 0% and 1.5% or less, Nb: more than 0% and 1.5% or less, Zr: 0% More than 1.5%, Hf: more than 0% and 1.5% or less, Ta: more than 0% and 1.5% or less, W: more than 0% and 1.5% or less, and Cu: more than 0% 1.5 % Or less of 1 type or 2 types or more.

<Structure of alloy wire>
Hereinafter, the structure of the alloy wire of the present invention will be described.
The alloy wire of the present invention has crystal grains in which (Mo, V) C-based composite carbide containing both Mo and V (hereinafter sometimes referred to as “composite carbide”) exists.

When the amounts of Mo and V contained in the (Mo, V) C-based composite carbide are {Mo} and {V}, respectively, the value of {Mo} / {V} is 0.2 or more and 4.0 or less. . If the value of {Mo} / {V} is less than 0.2, Mo-deficient carbides are formed, hardness and strength are reduced, and intragranular carbides are formed and grown quickly in aging heat treatment, resulting in high hardness. In addition, the temperature range of aging heat treatment that can maintain high strength is narrowed, and high hardness and high strength cannot be obtained under aging conditions in a wide temperature range. Therefore, the value of {Mo} / {V} is adjusted to 0.2 or more, preferably 0.3 or more, and more preferably 0.4 or more. When the value of {Mo} / {V} is 0.2 or more, precipitation hardening and its strengthening can be optimized. On the other hand, if the value of {Mo} / {V} exceeds 4.0, V-deficient carbides are formed, the hardness and strength are reduced, and the formation and growth of intragranular carbides occur early in the aging heat treatment. The temperature range of aging heat treatment that can maintain hardness and high strength is narrowed, and high hardness and high strength cannot be obtained under aging conditions in a wide temperature range. Therefore, the value of {Mo} / {V} is adjusted to 4.0 or less, preferably 3.7 or less, and more preferably 3.4 or less. When the value of {Mo} / {V} is 4.0 or less, precipitation hardening and its strengthening can be optimized.

The value of {Mo} / {V} is obtained as follows. A specimen is taken from the alloy wire and the cross section of the specimen is polished. The composition of carbides present inside the crystal grains is analyzed using a transmission electron microscope (TEM) and an energy dispersive X-ray fluorescence analyzer (EDX). Specifically, using TEM, the microstructure of the cross section of the polished specimen is observed, and using EDX, (Mo, V) C-based composite carbide existing inside the crystal grains is identified, and (Mo , V) The amount of Mo and V contained in the C-based composite carbide is measured, and the value of {Mo} / {V} is obtained.

The density of (Mo, V) C-based composite carbide in the crystal grains is preferably 10 pieces / μm ² or more. If the density of the (Mo, V) C-based composite carbide in the crystal grains is less than 10 pieces / μm ² , the precipitates are few and the strength may be reduced, but the (Mo, V) C in the crystal grains may be low. When the density of the system composite carbide is 10 pieces / μm ² or more, precipitation hardening and its strengthening can be optimized.

Ratio of the number of (Mo, V) C-based composite carbides having a diameter of 150 nm or less to the total number of (Mo, V) C-based composite carbides in the crystal grains (the presence of (Mo, V) C-based composite carbides having a diameter of 150 nm or less The ratio is preferably 50% or more, more preferably 70% or more, and still more preferably 90% or more. When the ratio of the number of (Mo, V) C-based composite carbides having a diameter of 150 nm or less to the total number of (Mo, V) C-based composite carbides in the crystal grains is less than 50%, a large number of coarse particles are formed, Although there is a risk of low strength, the ratio of the number of (Mo, V) C composite carbide having a diameter of 150 nm or less to the total number of (Mo, V) C composite carbide in the crystal grains is 50% or more. Precipitation hardening and its strengthening can be optimized.

The density of the (Mo, V) C-based composite carbide in the crystal grains and the abundance of the (Mo, V) C-based composite carbide having a diameter of 150 nm or less are measured as follows using TEM and EDX. Using TEM, the microstructure of the cross section of the polished specimen is observed, and (Mo, V) C-based composite carbide existing in the crystal grains is identified by composition analysis using electron diffraction and EDX. In addition, the total number of (Mo, V) C-based composite carbides is counted from the TEM bright field images observed and photographed at a magnification of 5,000 to 200,000 according to the size of the carbides present in the crystal grains. The number of (Mo, V) C-based composite carbides having a diameter of 150 nm or less existing in the field image is counted. Based on the observation area of the TEM bright field image and the total number of (Mo, V) C composite carbides present in the TEM bright field image, the density of (Mo, V) C composite carbide (pieces / μm). ² ). Based on the total number of (Mo, V) C-based composite carbides counted by the above method and the number of (Mo, V) C-based composite carbides having a diameter of 150 nm or less, the total number of (Mo, V) C-based composite carbides The ratio of the number of (Mo, V) C-based composite carbides having a diameter of 150 nm or less to the number (the presence ratio of (Mo, V) C-based composite carbides of 150 nm or less) is determined. The major axis of the (Mo, V) C-based composite carbide (that is, the diameter of a circle circumscribing the (Mo, V) C-based composite carbide) is defined as the diameter of the (Mo, V) C-based composite carbide.

<Characteristics of alloy wire>
The tensile strength (TS) of the alloy wire of the present invention is preferably 1300 MPa or more, more preferably 1400 MPa or more, and even more preferably 1500 MPa or more. The elongation (EL) of the alloy wire of the present invention is preferably 0.8% or more, more preferably 1.0% or more. TS and EL are measured by carrying out a tensile test according to JIS Z 2241 on a test piece prepared from an alloy wire.

The twist value of the alloy wire of the present invention measured at a distance between the gauge points 100 times the final wire diameter of the alloy wire of the present invention is preferably 20 times or more, more preferably 60 times or more. The twist value is measured as follows. One end of a test piece prepared from an alloy wire is fixed, the other end of the test piece is twisted, and the number of twists until the test piece breaks is measured as a twist value. The distance between the gauge points is 100 × D (D represents the final wire diameter of the test piece), and the twisting speed is 60 rpm. In the present invention, “wire diameter” means the diameter of a circle when the cross section of the test piece is a circle, and the equivalent circle diameter converted from the area of the cross section when the cross section of the test piece is not a circle. Means. In the present invention, the “equivalent circle diameter” means the diameter of a circle having the same area as the cross-sectional area of the test piece.

The average linear thermal expansion coefficient between two points from 15 ° C. to 100 ° C. of the alloy wire of the present invention is preferably 3.4 × 10 ⁻⁶ / ° C. or less, more preferably 3.0 × 10 ⁻⁶ / ° C. or less. It is. The average linear thermal expansion coefficient between two points from 15 ° C. to 230 ° C. of the alloy wire of the present invention is preferably 4.4 × 10 ⁻⁶ / ° C. or less, more preferably 4.0 × 10 ⁻⁶ / ° C. or less. It is. The average linear thermal expansion coefficient between two points from 100 ° C. to 240 ° C. of the alloy wire of the present invention is preferably 4.4 × 10 ⁻⁶ / ° C. or less, more preferably 4.0 × 10 ⁻⁶ / ° C. or less. It is. The average linear thermal expansion coefficient between two points from 230 ° C. to 290 ° C. of the alloy wire of the present invention is preferably. It is 11.4 × 10 ⁻⁶ / ° C. or less, more preferably 11.0 × 10 ⁻⁶ / ° C. or less. The linear thermal expansion coefficient is measured as follows. Measure the displacement of the test piece in the temperature rising process with a Formaster tester (Formaster-EDP, manufactured by Fuji Electric Koki Co., Ltd.). Average linear thermal expansion coefficient between two points from 15 ° C to 100 ° C, 15 ° C Average linear thermal expansion coefficient between two points from 1 to 230 ° C, average linear thermal expansion coefficient between two points from 100 ° C to 240 ° C, and average linear thermal expansion coefficient between two points from 230 ° C to 290 ° C Measure.

<Form of alloy wire>
The form of the alloy wire of the present invention is not particularly limited as long as it is linear. Examples of the form of the alloy wire of the present invention include a round wire, a flat wire, and a square wire. The wire diameter of the alloy wire of the present invention is not particularly limited, but is, for example, 2.0 to 3.8 mm. The meaning of “wire diameter” is as described above.

<Method for producing alloy wire>
The alloy wire of the present invention can be produced, for example, by the following method. A steel material having a desired shape such as a round bar or square bar by hot forging or hot rolling after melting the steel having the alloy composition of the present invention and producing a steel ingot or bloom by ingot forming or continuous casting. To form. Thereafter, the alloy wire of the present invention can be manufactured by sequentially performing solution treatment, wire drawing and aging heat treatment on the steel material. For example, the solution treatment can be performed at a heating temperature of 1200 ° C. and a heating time of 30 minutes. The solution treatment can be omitted if rapid cooling such as water cooling is performed immediately after the steel material manufacturing process by hot forging or hot rolling. The aging heat treatment can be performed, for example, at a heating temperature of 625 ° C. and a heating time of 2 hours. It is preferable to cold work the steel after the solution treatment and before the aging heat treatment.

The alloy wire having the alloy composition of the present invention has a wide range of aging heat treatment conditions (temperature and holding time of the temperature) for obtaining high hardness. Therefore, when imparting hardness by aging heat treatment, it is possible to avoid a decrease in hardness due to a change in manufacturing conditions (for example, material, heating temperature, heating time, etc.), poor control, and the like. In addition, in the aging heat treatment, even when an excessive heat treatment is performed, a significant decrease in hardness due to the excessive heat treatment can be avoided. Such stability is caused by precipitation of (Mo, V) C-based composite carbide having a value of {Mo} / {V} of 0.2 or more and 4.0 or less in the crystal grains in the aging heat treatment. It is an effect.

<Coated alloy wire>
The coated alloy wire of the present invention includes the alloy wire of the present invention and an Al coating layer (Al coating) or a Zn coating layer (Zn coating) formed on the surface of the alloy wire of the present invention. The coated alloy wire of the present invention has corrosion resistance due to the Al coating layer or the Zn coating layer in addition to the same effects as the alloy wire of the present invention. The Al coating layer can be formed by a known method such as conform extrusion. The Zn coating layer can be formed by a known method such as plating.

Hereinafter, the present invention will be described in more detail based on examples.
Ingots were obtained by melting 50 kg of alloys having the composition shown in Table 1 (Invention Examples No. 1 to 30) and Table 2 (Comparative Examples No. 31 to 55) in a vacuum induction melting furnace (VIM). . The ingot was heated at 1200 ° C. for 1 hour and forged into a steel bar having a diameter of 20 mm. The steel bar was subjected to a solution treatment under the conditions of a heating temperature of 1200 ° C. and a heating time of 30 minutes. The steel bar after solution treatment was turned to a diameter of 15 mm, and then drawn at room temperature to produce an alloy wire with a wire diameter of 8 mm. In Tables 1 and 2, [Mo], [V] and [C] represent the amounts of Mo, V and C contained in the alloy, respectively.

[Evaluation of carbide in grains after aging heat treatment]
A test piece (length: 10 mm) prepared from an alloy wire having a wire diameter of 8 mm was subjected to an aging heat treatment under the conditions of a heating temperature of 500 to 1000 ° C. and a heating time of 30 minutes to 24 hours.

The test piece after the aging heat treatment was analyzed for the composition of carbides present in the crystal grains using a transmission electron microscope (TEM) and an energy dispersive X-ray fluorescence analyzer (EDX). Analysis by TEM and EDX was performed as follows. Using TEM, the microstructure of the cross section of the polished specimen is observed, and using EDX, (Mo, V) C-based composite carbide existing in the crystal grains is identified, and (Mo, V) C-based is identified. The amount of Mo and V contained in the composite carbide was measured, and the value of {Mo} / {V} was determined. The results are shown in Table 3 (Invention Examples No. 1 to 30) and Table 4 (Comparative Example Nos. 31 to 55). In Tables 3 and 4, {Mo} and {V} represent the amounts of Mo and V contained in the (Mo, V) C-based composite carbide, respectively.

About the test piece after aging heat processing, the density of the (Mo, V) C type complex carbide which exists in a crystal grain was analyzed using TEM and EDX. Analysis by TEM and EDX was performed as follows. Using TEM, the microstructure of the cross section of the polished specimen was observed, and (Mo, V) C-based composite carbide existing inside the crystal grains was identified by composition analysis using electron diffraction and EDX. And the amount of Mo and V contained in the (Mo, V) C-based composite carbide was measured, and the value of {Mo} / {V} was determined. The value of {Mo} / {V} of the composite carbide targeted in the present invention is 0.2 to 4.0. For the quantification of the dispersion state, the total number of (Mo, V) C-based composite carbides is counted from a TEM bright field image observed and photographed at a magnification of 5,000 to 200,000 according to the size of carbides present in the crystal grains. In addition, the number of (Mo, V) C-based composite carbides having a diameter of 150 nm or less present in the TEM bright field image was counted. Based on the observation area of the TEM bright field image and the total number of (Mo, V) C composite carbides present in the TEM bright field image, the density of (Mo, V) C composite carbide (pieces / μm). ² ) was obtained. Based on the total number of (Mo, V) C-based composite carbides counted by the above method and the number of (Mo, V) C-based composite carbides having a diameter of 150 nm or less, the total number of (Mo, V) C-based composite carbides The ratio of the number of (Mo, V) C-based composite carbide having a diameter of 150 nm or less to the number (the presence ratio of (Mo, V) C-based composite carbide having a diameter of 150 nm or less) was determined. The major axis of the (Mo, V) C-based composite carbide (that is, the diameter of a circle circumscribing the (Mo, V) C-based composite carbide) was defined as the diameter of the (Mo, V) C-based composite carbide. The value of {Mo} / {V} of the (Mo, V) C-based composite carbide satisfies 0.2 to 4.0, and at the same time, the density is 10 pieces / μm ² or more and the diameter is 150 nm or less (Mo, V V) When the abundance of the C-based composite carbide is 50% or more, “A: the target composite carbide exists and the dispersion state is good”, (Mo, V) C-based composite carbide {Mo} / { When the value of V} satisfies 0.2 to 4.0, but the density is less than 10 pieces / μm ² or the abundance of (Mo, V) C-based composite carbide having a diameter of 150 nm or less is less than 50% “B: The target composite carbide exists but the dispersion state is poor”, and the value of {Mo} / {V} of the (Mo, V) C-based composite carbide does not satisfy 0.2 to 4.0. Was evaluated as “F: composite carbide defect”. Evaluation F is outside the scope of the present invention. The results are shown in Table 3 (Invention Examples No. 1 to 30) and Table 4 (Comparative Example Nos. 31 to 55).

[Evaluation of thermal aging stability]
An aging heat treatment was performed on a test piece (length: 100 mm) produced from an alloy wire having a wire diameter of 8 mm, with the heating time fixed at 6 hours and the heating temperature varied between 610-650 ° C. JIS No. 14A test specimens are produced by machining the specimens before aging treatment and after aging heat treatment, and tensioned according to JIS Z 2241 using a tensile tester (100 kN universal testing machine, manufactured by Shimadzu Corporation). The test was conducted and the tensile strength (TS) was measured. Create a curve with the aging temperature on the horizontal axis and the tensile strength on the vertical axis (see Fig. 1). Based on this curve, a temperature range that can ensure a tensile strength of 96% or more of the maximum tensile strength (MAX6hr) Asked. The case where the temperature range in which the tensile strength of 96% or more of the maximum tensile strength (MAX 6 hr) can be secured is 30 ° C. or more is “A: good thermal aging stability”, and the case where the temperature range is less than 30 ° C. is “F: The thermal aging stability was poor. The results are shown in Table 5 (Invention Examples No. 1 to 30) and Table 6 (Comparative Example Nos. 31 to 55). 1 shows a curve in which the horizontal axis is the aging temperature and the vertical axis is the tensile strength when the aging heat treatment is performed with the heating time fixed at 6 hours and the heating temperature varied between 610 ° C. and 650 ° C. In this curve, the temperature range in which 96% or more of the maximum tensile strength (MAX 6 hr) can be secured is 32 ° C.

[Evaluation of aging stability over time]
An aging heat treatment was performed on a test piece (length: 100 mm) produced from an alloy wire having a wire diameter of 8 mm, with the heating temperature fixed at 650 ° C. and the heating time varied between 30 minutes and 9 hours. JIS14A test piece is prepared by machining the test piece before aging treatment and after aging heat treatment, and tensioned according to JIS Z 2241 using a tensile tester (500 kN universal testing machine, manufactured by Shimadzu Corporation). The test was conducted and the tensile strength (TS) was measured. Create a curve with aging temperature on the horizontal axis and tensile strength on the vertical axis (see Fig. 2). Based on this curve, a time range in which a tensile strength of 97% or more of the maximum tensile strength (MAX 650 ° C) can be secured. Asked. When the time range in which a tensile strength of 97% or more of the maximum tensile strength (MAX 650 ° C.) can be secured is 3 hours or more, “A: good aging stability over time” and “F” : Aging stability over time was poor. The results are shown in Table 5 (Invention Examples No. 1 to 30) and Table 6 (Comparative Example Nos. 31 to 55). In FIG. 2, when the aging heat treatment is performed with the heating temperature fixed at 650 ° C. and the heating time varied between 30 minutes and 9 hours, the horizontal axis represents the aging temperature and the vertical axis represents the tensile strength. It is an example of a curve. In this curve, the time range in which a tensile strength of 97% or more of the maximum tensile strength (MAX 650 ° C.) can be secured is 3.8 hours.

When the thermal aging stability and the temporal aging stability were both evaluated as A, the following evaluation was performed, but when either was evaluated as F, the following evaluation was not performed.

[Evaluation of tensile properties after aging treatment]
An aging heat treatment was performed on a test piece (length: 300 mm) produced from an alloy wire having a wire diameter of 8 mm under the conditions of a heating temperature of 500 to 1000 ° C. and a heating time of 30 minutes to 24 hours. The test piece after the aging heat treatment was drawn at room temperature to prepare a test piece (length 400 mm or more) having a wire diameter of 3.1 mm. Using a tensile tester (100 kN universal testing machine, manufactured by Shimadzu Corporation) on a tensile test piece having a wire diameter of 3.1 mm and a gauge length of 250 mm, a tensile test at a stroke speed of 20 mm / min or less at room temperature. And tensile strength (TS) and elongation (EL) were measured. When TS is 1500 MPa or more and EL is 0.8% or more, “A: tensile property is very good”, when TS is less than 1500 MPa, 1400 MPa or more and EL is 0.8% or more, “B : Tensile property is good ”, TS is less than 1400 MPa, 1300 MPa or more, and EL is 0.8% or more.“ C: Tensile property is generally good ”, TS is less than 1300 MPa, or EL is 0.8%. The case where it was less than "F: Tensile properties were poor" was evaluated. The results are shown in Table 5 (Invention Examples No. 1 to 30) and Table 6 (Comparative Example Nos. 31 to 55). When the evaluation was A, B, or C, the following evaluation was performed. However, when the evaluation was F, the following evaluation was not performed.

[Evaluation of twist value after aging heat treatment]
The twist value of a test piece (length: 310 mm) having a wire diameter of 3.1 mm produced in the same manner as described above was measured. The twist value was measured as follows. One end of the test piece was fixed, the other end of the test piece was twisted, and the number of twists until the test piece was broken was measured as a twist value. The distance between the gauge points was 100 D (D represents the final wire diameter of the test piece), and the twisting speed was 60 rpm. When the twist value is 60 times or more, “A: The twist value is very good”, and when the twist value is 20 to 59 times, “B: The twist value is good”, and the twist value is 20 times. The case where it was less than "F: Twist value is bad" was evaluated. The results are shown in Table 5 (Invention Examples No. 1 to 30) and Table 6 (Comparative Example Nos. 31 to 55). When it was evaluated as A or B here, the following evaluation was performed. When it was evaluated as F here, the following evaluation was not performed.

[Evaluation of linear thermal expansion coefficient after aging heat treatment]
The linear thermal expansion coefficient of a test piece having a wire diameter of 3.1 mm produced in the same manner as above was measured. The linear thermal expansion coefficient was measured as follows. Measure the displacement of the test piece in the temperature rising process with a Formaster tester (Formaster-EDP, manufactured by Fuji Electric Koki Co., Ltd.). Average linear thermal expansion coefficient between two points from 15 ° C to 100 ° C, 15 ° C Average linear thermal expansion coefficient between two points from 1 to 230 ° C, average linear thermal expansion coefficient between two points from 100 ° C to 240 ° C, and average linear thermal expansion coefficient between two points from 230 ° C to 290 ° C Was measured. When the average linear thermal expansion coefficient between two points from 15 ° C. to 100 ° C. is 3.0 × 10 ⁻⁶ / ° C. or less, “A: linear thermal expansion coefficient is extremely low”, 3.0 × 10 ⁻⁶ / B is less than 3.5 × 10 ⁻⁶ / ° C., “B: low linear thermal expansion coefficient”, and 3.5 × 10 ⁻⁶ / ° C. or more, “F: linear thermal expansion coefficient is High ”. Further, when the average linear thermal expansion coefficient between two points from 15 ° C. to 230 ° C. is 4.0 × 10 ⁻⁶ / ° C. or less, “A: the linear thermal expansion coefficient is extremely low”, 4.0 × 10 ^-6 / case of less than 4.5 × ^{10 -6} / ° C. beyond ° C. "B: a low linear thermal expansion coefficient", the case of 4.5 × ^{10 -6} / ° C. or more "F: linear thermal expansion The coefficient is high. " Further, when the average linear thermal expansion coefficient between two points from 100 ° C. to 240 ° C. is 4.0 × 10 ⁻⁶ / ° C. or less, “A: the linear thermal expansion coefficient is extremely low”, 4.0 × 10 ^-6 / case of less than 4.5 × ^{10 -6} / ° C. beyond ° C. "B: a low linear thermal expansion coefficient", the case of 4.5 × ^{10 -6} / ° C. or more "F: linear thermal expansion The coefficient is high. " Furthermore, the case where the average linear thermal expansion coefficient between two points from 230 ° C. to 290 ° C. is 11.0 × 10 ⁻⁶ / ° C. or less is expressed as “A: linear thermal expansion coefficient is extremely low”, 11.0 × 10 ^-6 / a of less than 11.5 × ^{10 -6} / ° C. beyond ° C. "B: a low linear thermal expansion coefficient", the case of more than 11.5 × ^{10 -6} / ° C. "F: linear thermal expansion The coefficient is high. " From the results of measuring and evaluating the above four temperature ranges, the linear thermal expansion coefficient of each test piece was further comprehensively evaluated. In the evaluation of the average linear thermal expansion coefficient from 15 ° C to 230 ° C, the average linear thermal expansion coefficient from 100 ° C to 240 ° C, and the average linear thermal expansion coefficient from 15 ° C to 290 ° C, all have one A or B evaluation. The overall evaluation when the other three are A evaluations is “A: The linear thermal expansion coefficient is very low”, and the two B evaluations are two, and the overall evaluation is “B: linear thermal expansion coefficient is The overall evaluation when the “low” one is A evaluation and the three are B evaluation is “C: linear thermal expansion coefficient is generally low”, and the overall evaluation when one or more F evaluations is “F: linear thermal expansion” The coefficient is high. " The results are shown in Table 5 (Invention Examples No. 1 to 30) and Table 6 (Comparative Example Nos. 31 to 55).

In addition, comparative example No. 49 and No. In No. 50, since B and Mg were excessive, hot workability was poor, and many cracks were generated during forging. Therefore, evaluation test pieces could not be prepared, and various evaluations were not performed.

Invention Example No. 1-No. 26
Condition a: satisfying the alloy composition of the present invention,
Condition b: (Mo, V) C-based composite carbide exists inside the crystal grains.
Condition c: The value of ([Mo] +2.8 [V]) / [C] is 9.6 or more and 21.7 or less, Condition d: The value of {Mo} / {V} is 0.2 or more and 4 0.0 or less,
Condition e: (Mo, V) C-based composite carbide has a density of 10 pieces / μm ² or more in crystal grains and has a diameter of 150 nm or less (Mo, V) with respect to the total number of (Mo, V) C-based composite carbides. V) The ratio of the number of C-based composite carbides is 50% or more.
Condition f: When the Cr content is more than 0%, the value of ([Mo] + [V]) / [Cr] is 1.2 or more.
Condition g: When the content of Co is more than 0%, [Co] + [Ni] is 35% or more and 40% or less.
All the characteristics required for a high-strength, low-thermal-expansion alloy wire were A or B evaluations, that is, high strength, high twist value, good ductility, and low thermal expansion coefficient. In addition, Invention Example No. 1-No. No. 26 was excellent in aging stability (thermal aging stability and aging stability over time).

In addition, Invention Example No. 27-No. 30 satisfies all the conditions a to d and is generally excellent in wear resistance, high strength, good ductility, low thermal expansion coefficient and aging stability (thermal aging stability and aging stability over time). There is C evaluation which does not satisfy any one of the conditions e to g and is slightly inferior to B evaluation in any one of them.

On the other hand, Comparative Example No. 31-No. 55 does not satisfy any one or more of conditions a to d, and is at least one of strength, twisting characteristics, ductility, thermal expansion coefficient, and aging stability (thermal aging stability and aging stability over time) The species was F rated and lacked the necessary properties.

Claims

% By mass
C: 0.1% or more and 0.4% or less,
Si: 0.1% or more and 2.0% or less,
Mn: more than 0% and 2.0% or less,
Ni: 25% to 40%,
V: 0.5% to 3.0%,
Mo: 0.4% or more and 1.9% or less,
Cr: 0% to 3.0%,
Co: 0% to 3.0%,
B: 0% or more and 0.05% or less,
Ca: 0% or more and 0.05% or less,
Mg: 0% to 0.05%,
Al: 0% to 1.5%,
Ti: 0% to 1.5%,
Nb: 0% to 1.5%,
Zr: 0% to 1.5%,
Hf: 0% to 1.5%,
Ta: 0% to 1.5%,
W: 0% to 1.5%,
Cu: 0% to 1.5%,
O: 0% or more and 0.005% or less, and N: 0% or more and 0.03% or less, and the balance is a high strength low thermal expansion alloy wire composed of Fe and inevitable impurities,
In the alloy wire crystal grains, there is a (Mo, V) C-based composite carbide containing both Mo and V.
When the amounts of Mo, V and C contained in the alloy wire are [Mo], [V] and [C], respectively, the value of ([Mo] +2.8 [V]) / [C] is 9. 6 to 21.7,
When the amount of Mo and V contained in the (Mo, V) C-based composite carbide is {Mo} and {V}, respectively, the value of {Mo} / {V} is 0.2 or more and 4.0 or less. The high strength low thermal expansion alloy wire.
In the crystal grains, the density of the (Mo, V) C-based composite carbide is 10 pieces / μm 2 or more, and the (Mo, V) C-based composite carbide has a diameter of 150 nm or less with respect to the total number of the (Mo, V) C-based composite carbides. , V) The high-strength, low-thermal-expansion alloy wire according to claim 1, wherein the ratio of the number of C-based composite carbides is 50% or more.
In mass%, Cr: more than 0%, including 3.0% or less,
When the amounts of Mo, V and Cr contained in the alloy wire are [Mo], [V] and [Cr], respectively, the value of ([Mo] + [V]) / [Cr] is 1.2 or more. The high-strength low thermal expansion alloy wire according to claim 1 or 2.
In mass%, Co: more than 0%, including 3.0% or less,
4. [Co] + [Ni] is 35% or more and 40% or less when the amounts of Co and Ni contained in the alloy wire are [Co] and [Ni], respectively. The high-strength low thermal expansion alloy wire according to Item.
In mass%, including B: more than 0% 0.05% or less, Ca: more than 0% 0.05% or less, and Mg: more than 0% 0.05% or less, The high-strength, low-thermal-expansion alloy wire according to any one of claims 1 to 4.
In mass%, Al: more than 0% and 1.5% or less, Ti: more than 0% and 1.5% or less, Nb: more than 0% and 1.5% or less, Zr: more than 0% and 1.5% or less, Hf: One or two of more than 0% and 1.5% or less, Ta: more than 0% and 1.5% or less, W: more than 0% and 1.5% or less, and Cu: more than 0% and 1.5% or less The high-strength, low-thermal-expansion alloy wire according to any one of claims 1 to 5, comprising at least a seed.
The high-strength, low-thermal-expansion alloy wire according to any one of Claims 1 to 6, comprising N: more than 0% and 0.03% or less in mass%.
The high-strength low-thermal-expansion alloy wire according to any one of claims 1 to 7, having a tensile strength of 1400 MPa or more.
The high-strength, low-thermal-expansion alloy wire according to any one of claims 1 to 8, wherein a twist value measured at a distance between gauge points 100 times the final wire diameter of the alloy wire is 20 times or more.
The high-strength, low-thermal-expansion alloy wire according to any one of claims 1 to 9, having an elongation of 0.8% or more.
The average linear thermal expansion coefficient between two points from 15 ° C. to 100 ° C. is 3 × 10 −6 / ° C. or less (15 to 100 ° C.), and the average linear thermal expansion coefficient between two points from 15 ° C. to 230 ° C. is 4 × 10 −6 / ° C. or lower (15 to 230 ° C.), average linear thermal expansion coefficient between two points from 100 ° C. to 240 ° C. is 4 × 10 −6 / ° C. or lower (100 to 240 ° C.) and 230 ° C. The high-strength, low-thermal-expansion alloy according to any one of claims 1 to 10, wherein an average linear thermal expansion coefficient between two points from 1 to 290 ° C is 11 × 10 -6 / ° C or less (230 to 290 ° C). line.
A high-strength low thermal expansion coating alloy comprising the high-strength low thermal expansion alloy wire according to any one of claims 1 to 11 and an Al coating layer or a Zn coating layer formed on a surface of the high-strength low thermal expansion alloy wire. line.