JP3191010B2 - High-strength low-thermal-expansion alloy wire having excellent torsion characteristics and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength, low-thermal-expansion alloy wire having excellent torsion characteristics of an Fe-Ni series having excellent strength and torsion characteristics, which is used for a core wire for a low sag heat-resistant transmission line. It is.

[0002]

2. Description of the Related Art In recent years, F having a high strength and a low coefficient of thermal expansion has been developed.
It is desired to develop an e-Ni-based alloy wire, for example, as a wire for the central portion of an overhead transmission line (ACSR) with low sag. For such an application, Japanese Patent Publication No. 56-59990
No., JP-A-55-41928, JP-B-57-1794.
No. 2, JP-A-55-122855, JP-A-55-12
No. 8565, JP-A-55-131155, JP-A-56
Japanese Patent Application Laid-Open Nos. -142851, 57-26144, 57-41350, 58-11767 and 58-11768 are disclosed.
Furthermore, for the purpose of improving the strength and torsion characteristics of these alloys, JP-B-63-56289, JP-B-60-346.
No. 13, JP-A-57-110659, Tokuhei 2-15
606, JP-A-58-77525, JP-A-58-2
10126, JP-A-58-221225, JP-A-5-222
No. 7-41350, Japanese Patent Publication No. 2-41577 and Japanese Patent Publication No. 2-55495 disclose a method for producing a high-strength low-thermal-expansion alloy wire or alloy wire.

[0003]

The above-mentioned conventional high-strength low-thermal-expansion alloys all contain 35% or more of Ni or Ni + Co.
In the range of 50%, C and N interstitial solid solution strengthening elements, and several substitutional solid solution strengthening elements such as Cr and Mo, and T
It has an alloy composition consisting of several kinds of precipitation strengthening elements such as i and Nb in a range not impairing the low thermal expansion characteristics, and the balance being Fe. In any of these alloys, in the solution heat treatment or the annealing heat treatment, good torsion characteristics can be obtained, but the tensile strength is at most 50 to 80 kgf / mm ² , and in this state, low sag overhead It is not suitable for applications of core wires for power transmission lines. However, each of these alloys has a higher work hardening ability than a typical Fe-Ni alloy such as a 36% Ni-Fe alloy or a 42% Ni-Fe alloy which is a conventional low thermal expansion alloy, A tensile strength of 100 kgf / mm ² or more can be obtained by processing. However, simply applying strong working in the cold region greatly reduces the torsion characteristics. Therefore, various manufacturing methods have been proposed to achieve both tensile strength and torsion characteristics.

For example, in Japanese Patent Publication No. 60-34613 and Japanese Patent Publication No. 2-15606, strain relief annealing is performed in a stage before cold working or in the middle of cold working to try to achieve both strength and torsion characteristics. Have been. It is specified in these manufacturing methods that good twisting characteristics can be obtained by removing surface distortion caused by peeling by annealing heat treatment.
The present inventor also performed a manufacturing test of a high-strength low-thermal-expansion alloy wire by this method. As a result, the twisting characteristics were not always stable, and variation was observed in the range of 5 to 80 times.

On the other hand, the alloy wire disclosed in Japanese Patent Publication No. 2-41577 and Japanese Patent Publication No. 2-55495 uses almost the same manufacturing process as the above-mentioned Japanese Patent Publication No. 60-34613 and Japanese Patent Publication No. 2-15606. However, it is described here that Mo2C carbide generated during annealing after cold working contributes to improvement in strength and torsion characteristics. Tokuho 2-415
One of the inventors of Japanese Patent Publication No. 77 and Japanese Patent Publication No. 2-55495 is "Effect of processes of drawing on torsional prop".
erty of high-tensile strength Invar alloywire '' (Wir
e Journal International vol.21, No.4 (1988), p.

In this paper, the improvement of the torsion characteristics is not sufficient only by performing an annealing heat treatment for precipitating Mo ₂ C carbide after cold working. In particular, in the hardness distribution of the cross section of the alloy wire after drawing, It is reported that a special jig called a Christopherson tube is required to reduce the die withdrawal angle and increase lubricity so that the hardness of the central portion becomes the highest. From this paper, the methods disclosed in the above-mentioned four patent publications (Japanese Patent Publication No. 60-34613, Japanese Patent Publication No. 2-15606, Japanese Patent Publication No. 2-41577 and Japanese Patent Publication No. 2-55495) are all disclosed by Regarding the production of a high-strength low-thermal-expansion alloy wire having excellent turning characteristics, it is clear that the necessary conditions are not sufficient conditions.

However, increasing the twisting characteristics by using a special jig called a Christopherson tube for reducing the die withdrawal angle or improving lubricity increases the number of drawing passes ( If the drawing angle is small, it is not possible to increase the reduction in area per pass), and it takes time to change the process of the line, and it is extremely efficient for the production of alloy wires having a total length of several km. Is a bad manufacturing method. In view of the above problems, the present inventors have elucidated the twisting mechanism, and have attempted to manufacture an alloy wire that can obtain a high twisting value by using a normal process of manufacturing a steel bar.

[0008]

Means for Solving the Problems The inventors of the present invention have manufactured a wire by a number of manufacturing processes using a hot-rolled Fe-Ni-based alloy material mixed with various additive elements, and manufactured the alloy wire. The tensile properties, torsion properties, and thermal expansion coefficient of the rubber were investigated. As a result, in order to obtain a low-thermal-expansion alloy wire having a tensile strength of 120 kgf / mm ² or more, it is important to make the texture of the cross section of the alloy wire uniform. It was found that, by setting the degree of orientation to 60% or more, a high twist value of 70 times or more can be stably obtained. Further, an optimal solution treatment for obtaining an alloy wire having a high degree of orientation of the {111} crystal plane,
Recovery heat treatment and cold working conditions were also found. Among these Fe—Ni-based high-torsion, high-strength, high-strength, low-thermal-expansion alloys, in particular, the upper limit temperature of the actual use of transmission lines is 23
The composition range in which the average coefficient of thermal expansion up to 0 ° C. can be suppressed to the lowest level was also clarified.

That is, among the high-strength low-thermal-expansion alloy wires having excellent torsion characteristics according to the present invention, the first invention relates to a Fe—Ni-based alloy having a tensile strength of 120 kgf / mm ² or more in a final processed wire diameter. In the texture of the cross section of the alloy wire,
(1) A high-strength low-thermal-expansion alloy wire having excellent twisting characteristics, wherein the degree of orientation of the crystal plane is 60% or more;
The invention is based on the finding that the alloy wire particularly has a C content of 0.15 to 0.30% by weight.
%, Si 0.5% or less, Mn 0.5% or less, Mo1.0
-4.0%, and Ni 30% or more and less than 38% and Co8
% Or less of Ni + Co is 35% or more and 38%
Fe-Ni-based alloy wire having a composition of Fe excluding impurities and a balance of less than 120 kgf / mm ^{2 in} the final processed wire diameter, and a cross section of the alloy wire In the texture of, the degree of orientation of the {111} crystal plane is 6
It is a high-strength low-thermal-expansion alloy wire excellent in twisting characteristics characterized by being 0% or more,

[0010] The third invention is based on the invention that the alloy wire has C
0.15 to 0.30%, Si 0.5% or less, Mn 0.5
% Or less, Mo 1.0 to 4.0%, B 0.0005 to 0.
02 and one or two of 30% or more and less than 38% of Ni and 8% or less of Ni in the range of 35% or more and less than 38% of Ni + Co, with the balance being Fe, excluding impurities,
A Fe—Ni-based alloy wire having a tensile strength of 120 kgf / mm ² or more at the final processing wire diameter, and in the texture of the cross section of the alloy wire, the degree of orientation of the {111} crystal plane is 60% or more. It is a high-strength low-thermal-expansion alloy wire excellent in twisting characteristics.

In a fourth aspect of the present invention, a Fe—Ni alloy wire is drawn after hot working or after hot working.
A solution heat treatment at 10 to 1150 ° C. is performed, and then cold working at a surface reduction rate of 20 to 60% is performed.
A high strength low thermal expansion alloy wire having excellent torsion characteristics, characterized by performing a recovery heat treatment at ℃ and then performing cold working with a surface reduction rate of 65% or more to obtain a predetermined wire diameter.

The fifth invention is characterized in that, in terms of% by weight, C 0.15 to 0.
30%, Si 0.5% or less, Mn 0.5% or less, Mo
An alloy material having a composition of 1.0 to 4.0%, and one or two of Ni 30% or more and less than 38% and Co 8% or less in the range of 35% or more and less than 38% by Ni + Co, with the balance being Fe excluding impurities. After hot working or after the hot working, wire drawing is performed, solution heat treatment at 1010 to 1150 ° C is performed, and then cold working at a surface reduction rate of 20 to 60% is applied, and then recovery at 550 to 800 ° C is performed. A method for producing a high-strength low-thermal-expansion alloy wire having excellent torsion characteristics, which comprises performing a heat treatment and then performing cold working with a surface reduction rate of 65% or more to obtain a predetermined wire diameter;

The sixth invention is characterized in that, in terms of% by weight, C 0.15-0.
30%, Si 0.5% or less, Mn 0.5% or less, Mo
One or two of 1.0 to 4.0%, B 0.0005 to 0.02%, Ni 30% or more and less than 38%, and Co 8% or less in the range of 35% or more and less than 38% by Ni + Co, with the balance being impurities. , After hot working or after the hot working, wire-drawing the alloy material having a composition of Fe
Perform a solution heat treatment at 150 ° C., and then reduce the area
After the 60% cold working, a recovery heat treatment at 550 to 800 ° C. is performed, and then the cold working with a surface reduction rate of 65% or more is performed to obtain a predetermined wire diameter. This is a method for producing a high-strength low-thermal-expansion alloy wire.

In the first and fourth aspects of the present invention, Fe-N
The i-based alloy wire includes Ni or Ni + Co in a range of 35 to 50%, and further includes a solid solution strengthening element selected from C, N, Cr, Mo, and the like, and Ti, N if necessary.
It has an alloy composition containing precipitation hardening elements such as b and W within a range that does not impair the low thermal expansion characteristics, and the balance substantially consisting of Fe. Further, the second invention, the third invention, the fifth invention, and the sixth invention
The alloy composition specified in the invention is also novel as a composition.

In the present invention, the ratio of the crystal orientation in the cross section of the alloy wire was obtained by a normal X-ray diffraction pattern (1).
{111}, {200}, {2} from the peak intensity ratios corresponding to (11), (200), (220) and (311).
The ratio between 20} and {311} is determined. $ 11
1} The crystal plane is the main slip plane of the austenitic alloy, and increasing the degree of orientation of the {111} crystal plane in the cross section of the alloy wire during the manufacturing stage makes it easy to slip in the shear direction during the torsion test. In this way, local twisting, that is, breaking of the alloy wire is less likely to occur. The alloy wire having a degree of orientation of the {111} crystal plane of less than 60% causes local torsion, and greatly varies in the range of 5 to 80 twists. Therefore, in the final working wire diameter obtained by the present invention, the tensile strength of 120 kgf / mm ² or more and the stable cross section of the Fe-Ni-based alloy wire having a high torsion value of 70 times or more at the time of the final working are as follows: The degree of orientation of the 111 ° crystal plane needs to be 60% or more. The greatest feature of the present invention is that the relationship between the degree of crystal orientation and the twisting characteristic has been found,
This is one of the major differences from the prior art.

The present inventors need to carefully control the solid solution and precipitation of Mo or Cr carbide in order to produce an alloy wire having a high degree of orientation of the {111} crystal plane as described above. It revealed that. That is, the carbide of Mo or Cr needs to be sufficiently dissolved once at a high temperature for the purpose of precipitating the carbide finely during hot-working or during drawing after hot-working and subsequent recovery heat treatment. There is. There are only a few known examples that describe heating at a high temperature in the conventional method for producing a high-strength low-thermal-expansion alloy wire and alloy wire, which can be found only in JP-A-57-41350.
This is a technology that has received little attention in the past. In JP-A-57-41350, the alloy wire is 900 to 1000
Although the purpose is unclear, heat treatment in this temperature range is inadequate because the solid solution of carbides of Mo or Cr is insufficient, and the subsequent annealing temperature range is also low. The torsion value seen in the example is at most 25
It stays at the level of ~ 50 times. Therefore, it is hard to say that the core wire of the overhead power transmission line has sufficient twisting characteristics in consideration of variation.

The solid solution temperature of the carbide of Mo or Cr is 1
010 ° C. or higher, and in order to precipitate fine Mo or Cr carbide for sufficient tensile strength and torsion value improvement in a post-process, it is necessary to carry out this process during hot working or during drawing after hot working. It is necessary to heat the solution to a temperature or more to perform a sufficient solution heat treatment. However, the solution heat treatment temperature is 11
If the temperature exceeds 50 ° C., decarburization occurs and the crystal grains become coarse and the strength decreases. Therefore, the solution heat treatment during the hot drawing of the alloy wire of the present invention or during the drawing after the hot working is 1010 to 1010.
Limit to the range of 1150 ° C. In the case of high-strength low-thermal-expansion alloy wires, by performing such a high-temperature solution heat treatment, carbides were uniformly and finely precipitated during the subsequent recovery heat treatment, and the degree of orientation of the {111} crystal plane was increased. This is one of the features of the invention.

The solution heat treatment may be performed after hot working, or may be performed in a step during cold working after hot working. In order to achieve the present invention, a step of cold working with a surface reduction of 20 to 60%, a subsequent recovery heat treatment, and a cold working with a surface reduction of 65% or more is included after the solution treatment. I just need. Since the solution heat treatment is heating at a high temperature, if an oxide layer (so-called scale) adheres to the surface of the wire, a step of removing the oxide layer as necessary before cold working is required. Of course. The removal of the oxide layer employs a method such as grinding, cutting, or pickling.

The alloy wire which has been subjected to a solution heat treatment is work-hardened in a later step of cold working than the alloy wire in which Mo or Cr exists as a carbide, and a tensile strength of 120 kgf / mm ² or more can be easily obtained. . However, in this case, in order to manufacture an alloy wire having a high degree of orientation of the {111} crystal plane, not only the solution heat treatment but also the recovery heat treatment during the cold working is very important. By performing the recovery heat treatment, many dislocations introduced by the cold working rearrange in the longitudinal direction of the alloy wire to form sub-grain boundaries (FIG. 1).
-B shows a representative tissue). At that time, carbides of Mo and Cr are finely precipitated at the sub-crystal grain boundaries, and have an effect of pinning the sub-crystal grain boundaries. Due to this effect, the recrystallization temperature is increased, and a recovered structure having a high degree of orientation of the {111} crystal plane can be obtained in a wide heat treatment temperature range.

In order to obtain such a recovery structure, it is necessary to define a cold working ratio and a recovery heat treatment temperature after the solution heat treatment until the recovery heat treatment. In order to obtain a uniform rearrangement structure of dislocations during the recovery heat treatment, it is necessary to introduce sufficient working strain by cold working. For this purpose, the cold work rate needs to be at least 20% or more. However, when the cold work rate exceeds 60%, the recovery / recrystallization temperature decreases, and the temperature falls below the precipitation temperature range of Mo or Cr carbide. As a result, the degree of orientation of the {111} crystal plane decreases. Therefore, the cold working ratio between the solution heat treatment and the recovery heat treatment of the alloy wire of the present invention is 20 to 60.
%.

FIG. 1 shows the recovery heat treatment temperature.
At a temperature lower than 550 ° C. as shown in FIG. 1A, rearrangement of dislocations does not occur. Conversely, when the temperature exceeds 800 ° C. as shown in FIG. 1C, recrystallization occurs and dislocations disappear, and carbides of Mo and Cr are coarse. Since the degree of work hardening during subsequent cold working is reduced and alloy wires having a tensile strength of 120 kgf / mm ² or more cannot be easily manufactured, the recovery heat treatment temperature is shown in FIG.
Is limited to the range of 550 to 800 ° C at which such a recovery tissue is obtained.

The alloy wire that has been subjected to the solution heat treatment, the cold working and the recovery heat treatment described above is subjected to a cold working of 65% or more to maintain a high twisting characteristic of 120 kg.
It can have a tensile strength of f / mm ² or more. 120 kg if the cold work rate after recovery heat treatment is less than 70%
Since the tensile strength of f / mm ² or more cannot be obtained and it is not suitable as the core wire of overhead power transmission lines, the cold working rate after recovery heat treatment is 65%.
% Or more.

The heat resistant temperature of the Al alloy of the Al transmission line having such a high-strength low-thermal-expansion alloy wire as the core wire is a maximum of approximately 230 ° C. at a continuous energizing temperature, and the core wire for suppressing the sag is from normal temperature to 230 ° C. A low coefficient of thermal expansion is required in the above temperature range. Conventional high-strength low-thermal-expansion alloy wires have been developed with emphasis on the average thermal expansion coefficient up to a temperature higher than 230 ° C., for example, up to 300 ° C. However, in practice, the upper limit of the operating temperature of the transmission line is determined by the heat resistant temperature of Al. Therefore, the high-strength low-thermal-expansion alloy has an average thermal expansion coefficient up to 230 ° C., which is the upper limit of the continuous conduction temperature of the Al alloy. This is particularly problematic.

The reasons for limiting the components of the novel alloy composition range in which the average thermal expansion coefficient from room temperature to 230 ° C. is particularly low among the Fe—Ni high twist high strength low thermal expansion alloy wires will be described below. C has the effect of significantly improving the cold work hardening ability of the alloy wire of the present invention together with Mo described below. C required for that is at least 0.15%,
Since excessive addition of C exceeding 0.3% causes an increase in the coefficient of thermal expansion, the amount of C is limited to 0.15 to 0.30%. S
i and Mn are included in the alloy wire of the present invention as deoxidizing elements. However, excessive amounts of Si and Mn cause an increase in the coefficient of thermal expansion.

Of the many strengthening elements, Mo has the greatest hardening ability by cold working when added in combination with C. This is thought to be due to the interaction between Mo, which is an interstitial solid-solution strengthening element, and C, which is a substitutional solid-solution strengthening element, in a solid solution state, and furthermore, a part thereof is precipitated as a fine secondary carbide of Mo ₂ C. Can be In addition, the fine secondary carbides precipitate along the sub-grain boundaries during the recovery heat treatment after the cold working after the solution heat treatment, and the dislocations rearrange in the longitudinal direction of the alloy wire to form {111} crystal planes. Increases the degree of orientation and contributes to the improvement of the twisting characteristics without lowering the strength. On the other hand, Cr is Mo
And contributes to strengthening for the same reason as Mo.
Since the thermal expansion coefficient becomes too high when solid solution strengthening is attempted as much as Mo, the addition of Mo alone is more effective, particularly for the purpose of lowering the thermal expansion coefficient up to 230 ° C. Therefore, the required Mo is at least 1.0%, but an excessive addition exceeding 4.0% causes an increase in the coefficient of thermal expansion, so that the Mo is limited to 1.0 to 4.0%.

In the alloy wire of the present invention, B segregates at the sub-grain boundary during the recovery heat treatment, like the secondary carbide of Mo, pinning the sub-grain boundary, and has the effect of expanding the proper range of the recovery heat treatment temperature. Have. That is. Without addition of B, 760-78
At 0 ° C. or higher, there is no problem in practical use, but the torsion value slightly decreases. However, the material to which B is added does not decrease the torsion value to 800 ° C., and a wide temperature range can be adopted. However, excessive addition exceeding 0.02% reduces hot workability, so B is limited to 0.02% or less. In the conventional Fe—Ni-based high-strength low-thermal-expansion alloy wire, there is no invention focusing on the effect of the addition of B, and this is one of the features of the present invention.

In the present invention, the Ni content greatly affects the thermal expansion characteristics. Especially from room temperature to 230 ° C
For the purpose of lowering the average coefficient of thermal expansion up to
When adding Ni alone, the amount is preferably in the range of 35% or more and less than 38%. If the amount of Ni is less than 35%, the transition point meaning the temperature at which the low thermal expansion characteristic disappears shifts to the lower temperature side, and the thermal expansion coefficient up to 230 ° C increases. Conversely, when Ni exceeds 38%, the transition point shifts to the high temperature side, but the coefficient of thermal expansion on the low temperature side increases as a whole, so that the coefficient of thermal expansion up to 230 ° C. also increases. For the above reasons, Ni is limited to the range of 35% or more and less than 38%.

Co is obtained by substituting a part of Ni.
The coefficient of thermal expansion up to 230 ° C. can be further reduced as compared with the case of using Ni alone. However, Co is more susceptible to martensitic transformation during cold working than Ni, and has a strong function of destabilizing the austenite phase. Therefore, Co can be replaced with Ni in a range of 8% or less. Therefore, Co becomes Ni
When combined with Ni, 30% or more and less than 38% of Ni and 8% or less of Co are limited to a range of 35% or more and less than 38% by Ni + Co. There are various possible addition elements for strengthening the Fe-Ni alloy other than the above-mentioned C, Cr and Mo.
Elements such as i, Nb, Ta, Hf, Zr, and W have a strong affinity for C, generate a lump-shaped hard primary carbide, easily form defects during cold working, and cause variations in torsion values. Therefore, excessive addition to the alloy wire of the present invention is not preferable.
Therefore, it is desirable that the upper limit of each of these elements is suppressed to about 0.2%.

Further, gas components such as O and N form inclusions in the alloy and also cause variation in the twist value. Therefore, in the alloy wire of the present invention, each is limited to 0.01% or less. . In addition, elements such as Al, Mg, Ca, and REM added for the purpose of deoxidation and desulfurization, which are usually contained in the following amounts, may have no problem in properties. Al, REM ≤ 0.1% Mg, Ca ≤ 0.02% The alloy wire according to the present invention, in particular, intended to lower the coefficient of thermal expansion from normal temperature to 230 ° C.
Is a Fe-Ni-based high-strength low-thermal-expansion alloy wire having a novel composition composed of:

[0030]

EXAMPLES (Example 1) An Fe-Ni-based alloy having the composition shown in Table 1 was melted and finished into a round bar having a diameter of 11.2 mm by hot forging and hot rolling.

[0031]

[Table 1]

[0032]

[Table 2]

Using this sample, a coil having a diameter of 4.6 mm or 3.5 mm was manufactured under various manufacturing conditions shown in Table 2 (only the comparative alloy wire M in Table 2 had a material diameter of 9 during solution heat treatment). .8 mm). Cold drawing was performed using a very common WC die having an approach angle of 12 °, and the wire was drawn with a reduction in area of about 20% per pass. The drawing speed at that time was the same speed as the drawing speed of a normal steel wire. Using these wires, a tensile test, a twist test, a thermal expansion test and an X-ray diffraction were carried out in the state of final processing. The elongation of the tensile test was measured at 250 mm between the gauge points,
The average value of tensile strength and elongation was determined for each of the three samples. In the torsion test, the distance between grips was 100 times the self-diameter,
Ten torsion values until breakage were measured at a rotation speed of 60 rpm, and an average value and a standard deviation were determined. In the X-ray diffraction, the degree of orientation of the {111} crystal plane was determined from the peak intensity ratio corresponding to the (111), (200), (220), and (311) X-ray diffraction patterns in the cross section of the alloy wire. Table 3 summarizes the results of these tests. 1A, 1B and 1C show the structures of the comparative alloy wire L, the inventive alloy wire A and the comparative alloy wire K after recovery heat treatment, respectively.

[0034]

[Table 3]

As can be seen from Table 3, the alloy wires A to D of the present invention (all of which are the alloy wires of the third invention) have a high degree of orientation of the {111} crystal plane without complicating the drawing step. , A high tensile strength and a stable high torsion value can be obtained. The microstructure of the alloy wire A of the present invention after the recovery heat treatment is shown in FIG. 1-b. The greatest feature of the alloy wire of the present invention is that it has such a structure in which dislocations rearrange in the drawing direction after the recovery heat treatment. . The alloy wire of the present invention also shows a low average thermal expansion coefficient at 30 to 230 ° C. In contrast, comparative alloy wires H to M
Has the same chemical composition as the alloy wire of the present invention, but is inferior in characteristics to the alloy wire of the present invention. The comparative alloy wire H was obtained by omitting the solution heat treatment of the alloy wire D of the present invention. Although the tensile strength of this alloy wire was close to that of the alloy wire of the present invention, the degree of orientation of the {111} crystal plane was high. It can be seen that the torsion value is low and the variation in the torsion value is large due to the low. From these results, it is clear how the solution heat treatment affects the stabilization of the torsion characteristics. Further, although the solution heat treatment was performed on the comparative alloy wire I, since the heat treatment temperature was low, the solid solution of Mo carbide was insufficient, and the degree of orientation of the {111} crystal plane was still insufficient, and The rounds are not sufficiently stable.

The comparative alloy wire J is an alloy wire having an intermediate cold drawing rate higher than that of the alloy wire B of the present invention.
Even in the recovery heat treatment at 30 ° C., the comparative alloy wire J is completely recrystallized, so that high work hardening ability due to the interaction between carbide and dislocation cannot be obtained, and the tensile strength is lower than that of the alloy wire of the present invention. The comparative alloy wire K is an alloy obtained by increasing the recovery heat treatment temperature of the alloy wire A of the present invention. As shown in FIG. 1-c, when the recovery heat treatment temperature is too high, a complete recrystallized structure is obtained, and the carbide is also coarsened. I understand. With such a structure, the work hardening ability in the subsequent cold working is reduced, and sufficient tensile strength cannot be obtained.

On the contrary, the comparative alloy wire L is an alloy obtained by lowering the recovery heat treatment temperature of the alloy wire D of the present invention. If the recovery heat treatment temperature is too low as shown in FIG. No phenomenon occurs. Therefore, although the tensile strength is high, the degree of orientation of the {111} crystal plane is low, and the twist value is significantly low. The comparative alloy wire M is an alloy wire having a lower finish cold work rate than the alloy wire A of the present invention. Even if the finish cold work rate is too low, the same tensile strength as the alloy wire of the present invention cannot be obtained. I understand.

Example 2 An Fe—Ni-based alloy having a composition shown in Table 4 was melted and finished into a round bar having a diameter of 11.2 mm by hot forging.

[0039]

[Table 4]

Using this sample, a coil having a diameter of 4.6 mm was manufactured under the same manufacturing conditions as in B of Table 2, and the same reliability test as in Example 1 was performed. Table 5 shows the accuracy test results.

[0041]

[Table 5]

Alloy wires Nos. 1, 2, 5, 7 and 8 are all alloy wires of the present invention, Nos. 1, 2, and 3 are first inventions, and No. 11, 12, and 13 are second inventions. , No.5, No.7,
8 and 21 are alloy wires corresponding to the third invention. Each alloy wire has a high degree of orientation of the {111} crystal plane, and a high tensile strength and a stable high torsion value can be obtained. However, the thermal expansion coefficient is greatly affected by the alloy composition. On the other hand, when the contents of C, Mo and Ni are limited as in the second and third inventions, the average coefficient of thermal expansion from 30 to 230 ° C. can take a lower value. In particular, it can be seen that the alloy wire in which part of Ni is replaced with Co has better low thermal expansion characteristics. The alloy wire of the third invention has a solid solution strengthening element such as C or Mo equal to or less than that of the alloy wire of the first invention (Cr
(Equivalent to 1.85 times in terms of Mo equivalent), but the tensile strength shows a value equal to or more than that. It is presumed that the effect of B segregating at sub-grain boundaries during recovery heat treatment is large. Is done.

[0043]

The alloy wire of the present invention has a high tensile strength and a high torsion value because the texture of the cross section is uniform in the degree of orientation of the {111} crystal plane to 60% or more. Further, according to the production method of the present invention, a carbide can be uniformly and finely precipitated by a combination of a solution heat treatment and a solution heat treatment, so that a stable and high twist characteristic can be obtained. Further, by making the specific alloy composition disclosed in the present invention, together with the above effects, it becomes possible to produce a core wire of a low sag transmission line having a lower coefficient of thermal expansion, and more than the conventional low sag transmission line Power transmission with high transmission capacity and excellent reliability becomes possible.

[Brief description of the drawings]

FIG. 1 is a transmission electron microscope microstructure photograph of the alloy wire of the present invention and a comparative alloy wire after recovery heat treatment.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-41928 (JP, A) JP-A-58-210126 (JP, A) JP-A-6-279945 (JP, A) JP-A-3-3 115543 (JP, A) JP-A-55-119156 (JP, A) Table 6 6-500361 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C22C 38/00-38 / 60 C21D 7 / 10,8 / 06

Claims (6)

(57) [Claims] 1. An Fe—Ni-based alloy wire having a tensile strength of 120 kgf / mm ² or more at the final working wire diameter, wherein the degree of orientation of the {111} crystal plane is 6 in the texture of the cross section of the alloy wire.
A high-strength low-thermal-expansion alloy wire excellent in twisting characteristics, characterized in that it is 0% or more. 2. The alloy composition of the Fe—Ni-based alloy wire according to claim 1, wherein C is 0.15 to 0.30% by weight,
0.5% or less, Mn 0.5% or less, Mo 1.0 to 4.0
% And one or two of Ni 30% or more and less than 38% and Co 8% or less in the range of 35% or more and less than 38% by Ni + Co, and the balance is made of Fe excluding impurities. High strength low thermal expansion alloy wire. 3. The alloy composition of the Fe—Ni alloy wire according to claim 1, wherein the alloy composition is such that C is 0.15 to 0.30% by weight,
0.5% or less, Mn 0.5% or less, Mo 1.0 to 4.0
%, B 0.0005 to 0.02%, Ni 30% or more and less than 38% and Co 8% or less Ni + Co
A high-strength low-thermal-expansion alloy wire having excellent torsion characteristics, characterized by containing Fe in the range of 35% or more and less than 38% and the balance being Fe. 4. After hot working or after hot working, the Fe—Ni alloy wire is drawn, subjected to a solution heat treatment at 1010 to 1150 ° C., and then cold worked at a surface reduction rate of 20 to 60%. 2. The twisting characteristic according to claim 1, wherein a recovery heat treatment at 550 to 800 ° C. is performed after the addition of the steel, and then a cold working with a surface reduction rate of 65% or more is performed to obtain a predetermined wire diameter. Manufacturing method of excellent high strength low thermal expansion alloy wire. 5% by weight of C, 0.15 to 0.30%, S
i 0.5% or less, Mn 0.5% or less, Mo 1.0 to 4.
An alloy material having a composition of 0% and one or two of Ni 30% or more and less than 38% and Co 8% or less in the range of 35% or more and less than 38% of Ni + Co, with the balance being Fe and excluding impurities, after hot working Alternatively, after the hot working, wire drawing is performed, and 1
A solution heat treatment at 010 to 1150 ° C. is performed, and then a cold working at a surface reduction rate of 20 to 60% is performed.
A method for producing a high-strength low-thermal-expansion alloy wire having excellent twisting characteristics, comprising performing a recovery heat treatment at 0 ° C., and then performing cold working with a surface reduction rate of 65% or more to obtain a predetermined wire diameter. 6. C 0.15 to 0.30% by weight, S
i 0.5% or less, Mn 0.5% or less, Mo 1.0 to 4.
0%, B 0.0005 to 0.02, and one or two types of Ni 30% or more and less than 38% and Co 8% or less as Ni + C
The alloy material having a composition of Fe, excluding impurities in the range of 35% or more and less than 38% in o, is subjected to a solution heat treatment at 1010 to 1150 ° C. after hot working or during wire drawing after hot working. After that, after performing cold working with a surface reduction rate of 20 to 60%, a recovery heat treatment at 550 to 800 ° C. is performed,
A method for producing a high-strength low-thermal-expansion alloy wire having excellent torsion characteristics, wherein cold-working with a surface reduction rate of 65% or more is performed to obtain a predetermined wire diameter.