JP3227072B2 - Method of manufacturing aluminum alloy wire for electric conduction - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an aluminum alloy wire which is excellent in strength, conductivity and heat resistance and is suitable as a conductor of a power cable.

[0002]

2. Description of the Related Art As a heat-resistant aluminum alloy wire for electric conduction, 60TAl (a heat-resistant aluminum alloy with 60% electric conductivity) and the like have been put into practical use.
l has a problem that the allowable temperature for a short time is as low as 180 ° C. On the other hand, an aluminum alloy wire having a conductivity of 60% or more and a high short-time allowable temperature of 280 ° C. or more is known (Japanese Patent Application Laid-Open No. 4-31549). However, such aluminum alloy wires are excellent in electrical conductivity and heat resistance, but have insufficient mechanical strength. In other words, even in the case of aluminum alloy wire with greatly improved conductivity and heat resistance, it is inevitable due to the environment in which the wire is laid, such as in mountainous areas or crossing the strait where it is difficult to construct a power transmission tower. In the case where it is necessary to wire the wire between the long diameters, or in applications where severe snow accretion, strong wind, etc. are exposed, it cannot be said that it has sufficient characteristics in terms of mechanical strength. Was. Therefore, there is a steel core aluminum stranded wire (ACSR) in which a high strength steel core wire is placed at the center of the aluminum stranded wire in order to impart strength to the aluminum alloy wire, but it is heavier and lighter than a single aluminum wire. Therefore, there is a problem that the strength is insufficient when used for an electric wire having a structure in which a steel core as a tension member is omitted. On the other hand, although the high strength alloy Al-Mg-Si alloy series No.A aluminum alloy wire has sufficient strength,
Current capacity is limited due to low electrical conductivity of 52% IACS and low heat resistance. Therefore, a conductive aluminum alloy wire having both conductivity and heat resistance while maintaining high strength is desired.

In view of the above, an object of the present invention is to provide a method for obtaining a conductive aluminum alloy having excellent strength, electrical conductivity, and heat resistance, and particularly improved strength.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above-mentioned object, and as a result, have used a specific alloy-based rough wire and applied a specific heat treatment to the rough wire derived from the alloy. And processing, it has been found that an aluminum alloy wire having high strength, high heat resistance and high electrical conductivity can be stably manufactured, and the present invention has been completed.

That is, in the present invention, in addition to Zr 0.1 to 0.5% by weight and Ti 0.01 to 0.08% by weight, Mg 0.005 to 0.5% by weight and Cu 0.005 to 0.5%
At least one selected from weight% and the alloy-derived rough wire containing the balance Al are heated from normal temperature to a temperature of 250 to 450 ° C. at a heating rate of 100 ° C./hour or less, and held for 2 to 100 hours. And then performing a process of reducing the cross-sectional area at a rate of 65% or more from a temperature of 40 ° C. or less.
In addition, after performing a process of reducing the cross-sectional area from a temperature of 40 ° C. or less to a cross-sectional area reduction rate of 65% or more, a heat treatment is further performed at a temperature of 150 to 350 ° C. for 1 to 20 hours to produce a conductive aluminum alloy wire. The method further comprises that the alloy further contains 0.05-1.0% by weight of Fe and 0.03-0.5% of Si.
The present invention relates to a method for producing a conductive aluminum alloy wire containing or containing at least one selected from the group consisting of at least one selected from the group consisting of:

[0006]

In the method for producing an aluminum alloy wire according to the present invention, the aluminum alloy used is Zr 0.1-0.5.
Wt% and Ti 0.01-0.08 wt% plus Mg
0.005 to 0.5% by weight and at least one selected from 0.005 to 0.5% by weight of Cu, and the balance of Al, or further containing 0.05 to 1.0% by weight of Fe and 0.
It contains at least one selected from 03 to 0.5% by weight. The alloy is cast, Zr is dissolved in the Al matrix in a supersaturated form, and then the temperature is raised from room temperature to a temperature of 250 to 450 ° C. at a temperature rising rate of 100 ° C./hour or less, and a heat treatment is performed for 2 to 100 hours. Finely precipitate and disperse as Al ₃ Zr. The processed structure is stabilized by the fine precipitates, and thus high heat resistance can be obtained without lowering the conductivity. Further, the addition of Fe and Si is
Promotes fine precipitation and dispersion of Al ₃ Zr. Further, at the time of casting, Ti refines the casting structure, thereby suppressing the occurrence of casting defects and enabling the production of high-quality rough drawn wires. In the subsequent processing at a cross-sectional area reduction rate of 65% or more from a temperature of 40 ° C. or less, solid solution Mg and Cu increase work hardening and increase strength.
The processing structure introduced in this processing was finely dispersed as described above.
Stabilized by Al ₃ Zr, thus achieving both high strength and heat resistance. Further, in order to alleviate the residual stress of the strongly processed structure, if necessary, 150 to
Heat treatment is performed at a temperature of 350 ° C. for 1 to 20 hours.

In the aluminum alloy, Zr is set to 0.1
The reason for setting to 0.5% by weight is that if it is less than 0.1% by weight, the heat resistance is not sufficient due to insufficient dispersion of Al ₃ Zr upon heat treatment.
If the content is more than 0.5% by weight, not only is it difficult to manufacture a rough drawn wire, but also it takes a long time for heat treatment to obtain electrical conductivity. A preferable addition amount of Zr is 0.2 to 0.4% by weight, more preferably 0.25 to 0.35% by weight.

[0008] The reason why the content of Ti is set to 0.01 to 0.08% by weight is that if the content is less than 0.01% by weight, the effect of suppressing the casting defects is not sufficient, and if it exceeds 0.08% by weight, the electrical conductivity is reduced. The preferable addition amount of Ti is 0.02 to 0.06% by weight, more preferably 0.03 to 0.05% by weight.

The alloy used in the present invention contains at least one selected from 0.005 to 0.5% by weight of Mg and 0.005 to 0.5% by weight of Cu in order to increase the strength.

The reason why Mg is set to 0.005 to 0.5% by weight is that 0.00
If the amount is less than 5% by weight, the strength during processing tends to be insufficient, and if it is more than 0.5% by weight, the electrical conductivity decreases. The preferable addition amount of Mg is 0.01 to 0.3% by weight, more preferably 0.02 to 0.2% by weight.

The reason why the content of Cu is 0.005 to 0.5% by weight is that 0.005 to 0.5% by weight is used.
If the amount is less than 5% by weight, the strength during processing tends to be insufficient, and if it is more than 0.5% by weight, the electrical conductivity decreases. The preferable addition amount of Cu is 0.01 to 0.3% by weight, more preferably 0.02 to 0.2% by weight.

When the alloy contains both Mg and Cu,
The total is preferably 0.01 to 0.6% by weight,
More preferably, it is 02 to 0.4% by weight.

[0013] The alloy used in the present invention is Al
_{3 In} order to promote the precipitation and dispersion of Zr, Fe0.05-1.
It is preferable to contain at least one selected from 0% by weight and 0.03 to 0.5% by weight of Si.

The reason why the content of Fe is set to 0.05 to 1.0% by weight is 0.05 weight.
If the amount is less than%, Al _ThreeZr precipitation, dispersion promotion
Tends to be inadequate, more than 1.0% by weight
This is because the electrical conductivity and the heat resistance tend to decrease. Good
Preferably, the amount of Fe added is 0.1-0.8% by weight, more preferably
0.12 to 0.5% by weight.

The content of Si in the range of 0.03 to 0.5% by weight is 0.03 weight%.
If the amount is less than%, Al _ThreeZr precipitation, dispersion promotion
Tends to be insufficient, more than 0.5% by weight
And the tendency of casting defects of rough wire to increase, as well as heat resistance
Is likely to decrease. Preferred amount of added Si
Is 0.05 to 0.3% by weight, more preferably 0.07 to 0.2% by weight
It is.

When the alloy contains both Fe and Si,
The total is preferably 0.08 to 1.2% by weight, and
More preferably, it is 1 to 0.8% by weight.

Al used in the present invention may contain ordinary impurities, which are usually contained in the Al.
It is preferable to use a base metal with a small amount of elements that lowers the conductivity as described above.

The method for producing the rough drawn wire used in the present invention is not particularly limited, but it can be obtained by subjecting the above aluminum alloy material to continuous casting and rolling, for example. Continuous casting and rolling methods include the Properci method, the Hezley method, and the SC method.
Known methods such as the R method and the speedem method can be employed. Preferably, the method is a Properch method.For example, a molten metal is poured between a rotating water-cooled copper mold wheel and an endless belt, and a solidified aluminum bar is continuously taken out when the wheel has rotated about 3/4, and the bar is rolled as it is. It is introduced into a machine and processed into a rough wire. 8 to 15 mm in diameter by continuous casting
At a casting temperature of 750 to 900
° C, and the obtained casting bar is preferably rolled at a cross-sectional area reduction rate of 80% or more while the temperature is 200 ° C or less.

The rough drawn wire is then heated from a normal temperature to a temperature of 250 to 450 ° C. at a temperature rising rate of 100 ° C./hour or less, kept for 2 to 100 hours, and then subjected to a heat treatment for cooling. This process resulted in supersaturated solid solution during casting and rolling.
Zr can be dispersed in the Al matrix as fine Al ₃ Zr. As a result, a substrate for forming a structure having sufficient strength and heat resistance can be obtained by cold working described later.

In the present invention, the heating from the room temperature at a heating rate of 100 ° C./hour or less during the heat treatment of the above-mentioned rough drawing is because Al ₃ Zr is finely and densely precipitated at a predetermined heat treatment temperature. In order to sufficiently generate nuclei, heat treatment at a rate of temperature rise of 100 ° C./hour or more, or a process in which a rough wire is suddenly inserted into a furnace at a predetermined temperature rather than from a room temperature is performed with a coarse and low density. This is because only precipitation and dispersion of Al ₃ Zr can be obtained, and in this case, both strength and heat resistance are significantly reduced. A preferred heating rate is 60 ° C /
Or less, particularly 5 to 50 ° C./hour.

The heat treatment temperature was set at 250 to 450 ° C.
Has sufficient Al at temperatures below 250 ° C. _ThreeZr precipitation and dispersion
Requires a very long heat treatment to obtain
Al higher than ℃_ThreeHeat resistance and strength for coarsening Zr particles
Is reduced. Preferred heat treatment temperature is 300 to
430 ° C, more preferably 320-420 ° C.
You. The reason why the heat treatment time is set to 2 to 100 hours is 2
Less than enough Al_ThreeNo precipitation or dispersion of Zr was obtained.
If it is longer than 00 hours, it has no industrial meaning.
You. The preferred heat treatment time is 4 to 80 hours, more preferably.
Preferably, it is 5 to 60 hours.

The cooling conditions are not particularly limited, and are usually 10 to 1
The cooling is performed at 000 ° C./hour, preferably 30 to 800 ° C./hour.

The heat-treated rough drawn wire is then subjected to cold working from a temperature of 40 ° C. or less to a cross-sectional area reduction rate of 65% or more. The reason for processing from 40 ° C. or lower is that when processing from a temperature higher than 40 ° C., the temperature increases during processing and the strength after processing decreases. The reason why the cross-sectional area reduction rate is 65% or more is that if the cross-sectional area reduction rate is less than 65%, sufficient work hardening cannot be obtained. Preferred cold working conditions are 30
This is a process in which the cross-sectional area reduction rate is 80% or more from a temperature of not more than ℃.

The cold-worked wire can be further subjected to a heat treatment at a temperature of 150 to 350 ° C. for 1 to 20 hours, if necessary. In the process up to cold working, the wire has a very high strength, but strength and heat resistance tend to be inversely proportional, so depending on the balance of required strength and heat resistance, In the case where the heat resistance is prioritized even if it is lowered, it is preferable to perform the above heat treatment in order to alleviate the residual stress and stabilize the metal structure. The reason for setting the heat treatment temperature to 150 to 350 ° C. in this heat treatment is that at a temperature lower than 150 ° C., the effect of relaxing the residual stress is not sufficient, and at a temperature higher than 350 ° C., the softening becomes remarkable and the strength decreases. . Further, the heat treatment time is set to 1 to 20 hours, because less than 1 hour tends to cause insufficient relaxation of residual stress, and longer than 20 hours tends to progress softening. Preferred heat treatment conditions are 200 to 30
0 ° C. for 2 to 10 hours, more preferably 210 to 2 hours.
3 hours to 8 hours at 80 ° C.

Further, in order to cut and remove a defect such as a flaw existing on the surface of the aluminum alloy wire, a wire surface peeling step may be inserted before or during the cold working. Here, the peeling step refers to a step of cutting and removing the surface of the wire into a thin shape with a constant thickness, and can be carried out at any stage of the wire drawing step from the rough drawn wire. For example, when a rough drawn wire is drawn, the drawn rough drawn wire is passed through one or more peeling dies at a stage where the cross-sectional area reduction rate is 3 to 80%. The thickness of the cut is appropriately selected according to the depth of a flaw or the like existing on the surface of the rough drawn wire and the cross-sectional area reduction rate of the wire.

[0026]

The present invention will be described below in more detail with reference to Examples and Comparative Examples.

Examples 1 to 10 and Comparative Examples 1 to 10 The alloys of Examples and Comparative Examples having the compositions shown in Table 1 (the balance being aluminum) were continuously cast and rolled by the Properch method.
A rough drawn wire having an outer diameter of 12 mm was obtained. After subjecting the rough drawn wire to a predetermined heat treatment, it is subjected to cold working to form an aluminum alloy wire (element wire), and if necessary, further subjected to a predetermined wire heat treatment to obtain a target conductive aluminum alloy wire. Was. The tensile strength, electrical conductivity and heat resistance of the alloy wires obtained in each of the examples and comparative examples were evaluated. Tensile strength is JIS Z-2
201. Conductivity is JIS H-0
505. The heat resistance was set to a temperature at which the tensile strength after heating for 1 hour became 90% of that before heating. In Table 1,
The alloy composition, the pouring temperature during continuous casting, and the rolling start and end temperatures during rolling are shown. Table 2 also shows the temperature rise rate, holding temperature and time of the rough drawing (WR) heat treatment, the starting temperature and the cross-sectional area reduction rate of the cold working, the wire heat treatment temperature and the time,
And properties of conductive aluminum alloy wire (tensile strength,
Conductivity and heat resistance).

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

According to the present invention, for example, a diameter of 3.8 mm
Of 25kgf / mm ² or more and 55% I
An aluminum alloy wire having a conductivity of ACS or more and a heat resistance temperature of 230 ° C. or more can be manufactured. In other words, a high-quality aluminum alloy wire for conductivity having excellent strength and heat resistance can be manufactured with good yield.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI C22F 1/00 650 C22F 1/00 650A 661 661A 691 691A 691B 691C 694 694A 694B H01B 1/02 H01B 1/02 B (58) Survey Field (Int.Cl. ⁷ , DB name) C22F 1/00-1/057 C22C 21/00-21/18 H01B 1/02 H01B 13/00

Claims (3)

(57) [Claims] 1. Zr 0.1-0.5% by weight and Ti 0.01-0.08
Wt% plus 0.005-0.5 wt% Mg and Cu
At least one type selected from 0.005 to 0.5% by weight, and a rough wire drawn from an alloy containing the balance of Al at 100 ° C /
The temperature is raised from room temperature to a temperature of 250 to 450 ° C. at a temperature rising rate of not more than time, and after keeping for 2 to 100 hours,
A method for producing a conductive aluminum alloy wire, characterized in that processing is performed from a temperature of 0 ° C. or less to a cross-sectional area reduction rate of 65% or more. 2. After performing a process of reducing the cross-sectional area by 65% or more from the temperature of 40 ° C. or less according to claim 1, the temperature is further increased by 150%.
A method for producing a conductive aluminum alloy wire, comprising heat-treating at a temperature of about 350 ° C. for about 1 to 20 hours. 3. The alloy further comprises 0.05-1.0% by weight of Fe and
3. The method for producing a conductive aluminum alloy wire according to claim 1, wherein the method contains at least one selected from 0.03 to 0.5% by weight of Si.