JPS6216269B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention improves the manufacturing method of Al-Zr alloy, which is known as a heat-resistant aluminum alloy for conductive use, and specifically, by combining the alloy composition and manufacturing process, it significantly improves strength and heat resistance without reducing conductivity. The present invention relates to a method for manufacturing a high-strength, heat-resistant aluminum alloy conductor. Traditionally, overhead power transmission lines mainly use steel-core aluminum stranded wires (ACSR), but under special power transmission conditions, steel-core heat-resistant aluminum alloy stranded wires (TACSR), which add heat resistance to aluminum conductors, are used. I came. As is known, Al--Zr alloys have been used as the aluminum alloys used in the TACSR wires. Regardless of the amount of Zr, the tensile strength of the conductor of Al-Zr alloys is not so high at 17 to 20 Kg/ ^mm2 , so it cannot be used as a conductor for long span power transmission, and all-aluminum alloy stranded wires cannot be used. (AAAC) could not be used. For this purpose, 5005 alloy (Al--0.5 to 1.1 wt% Mg) has been used as is known. This alloy has a high tensile strength of 24Kg/ ^mm2 , but its heat resistance is the same as ordinary aluminum wire (ECAl).
Large-capacity power transmission was not possible due to lack of heat resistance. However, with the recent increase in power demand, there has been a demand for conductors with heat resistance and high strength.The heat resistance of the known 5005 alloy has been improved, and the strength of the known heat resistant aluminum alloy has been improved. are desired by each. Furthermore, although the heat resistance of Al-Zr alloys, which are currently used as heat-resistant aluminum alloys for electrical conductivity, increases depending on the amount of Zr added, the electrical conductivity decreases, and therefore conductors with better heat resistance are not available. In order to obtain this, the amount of Zr must be increased, but the electrical conductivity will drop significantly, making it unsuitable for practical use. Furthermore, when various elements are added to improve strength, the electrical conductivity also decreases. In view of the above, the present invention was developed as a result of research into the combination of alloy composition and manufacturing process in order to provide a conductor with excellent strength and heat resistance without significantly reducing conductivity. It is. The aluminum alloy materials used in the present invention include Zr0.15-0.8wt%, Fe0.05-0.6wt%, Si0.04
Contains ~0.20wt%, and Mg0.005~0.5wt%,
Cu0.005~0.5wt%, rare earth elements 0.01~0.5wt%,
It contains one or more elements of 0.005 to 0.1 wt% Sb and 0.005 to 0.1 wt% Be, and consists of the remainder Al and normal impurities. The method of the present invention is a method in which the above alloy material is heated at 500 to 645°C, then rapidly cooled, cold processed to reduce the area by 65% or more, and then heat treated at 250 to 400°C for 1 to 400 hours. method), or in method (), the heat treatment process after 65% or more area reduction processing is divided into two stages, the first stage is heat treated at 200 to 400°C for 1 to 400 hours, and the second stage is the first stage. 1 to 30℃ higher than the stage and within the temperature range of 250 to 500℃
This relates to a method of heat treatment for 400 hours. The reason why the alloy composition is limited as described above in the present invention is as follows. In other words, Zr is added to improve strength and heat resistance, and the amount added is 0.15 to 0.8 wt% (hereinafter referred to as Zr).
wt% is simply abbreviated as %) because if it is less than 0.15%, the strength will be low and the heat resistance will not be improved.
This is because if it exceeds 0.8%, the effect of improving strength and heat resistance will be lost, and the electrical conductivity will also decrease. Like Zr, Fe is also added to improve strength and heat resistance, and the amount added is 0.05 to 0.6%.
This is because if the content is less than 0.05%, the effect will be small, and if it is more than 0.6%, no further improvement in strength or heat resistance will be observed and the electrical conductivity will decrease. The purpose of adding Si is to improve the strength, and the reason why the amount added is 0.04 to 0.20% is because if it is less than 0.04%, the strength will be low, and if it is more than 0.20%, the electrical conductivity will be low. . Mg and Cu are added to improve strength, and the amount of these added is set at 0.005 to 0.5%.If each is less than 0.005%, there is no strength improvement effect, and if each exceeds 0.5%, the electrical conductivity will decrease. This is because the decrease becomes large. Rare earth elements (hereinafter simply referred to as RE), Sb, Be
The purpose of adding is to improve strength and bending workability without reducing conductivity. The amount of RE added was set at 0.01 to 0.5% because if it is less than 0.01%, there is almost no effect, and if it exceeds 0.5%, the strength improvement effect disappears, the conductivity decreases, and the bending workability actually worsens. It is. In addition, the addition amount of Sb and Be was set to 0.005 to 0.1% each, but if it is less than 0.005% each, there is no effect of addition, and 0.1%.
This is because even if it is added in excess of %, no further improvement in strength will be observed, but rather the conductivity will decrease. In carrying out the present invention, Zr0.3~0.6%, Fe0.2~
Contains 0.4%, Si0.06~0.08%, Mg0.05~0.2
%, Cu0.05~0.2%, RE0.1~0.3%, Sb0.01~
A conductor with better performance can be obtained by using an alloy material having an alloy composition in which one or more of the following elements are added: 0.05% Be, and 0.01 to 0.05% Be. Further, if one or more of Mg and Cu and one or more of RE, Sb, and Be are simultaneously added within the above alloy composition range, a conductor with even more excellent performance can be obtained. Next, in the manufacturing steps (I) to () of the present invention, the above alloy material is heated at 500 to 645°C and then rapidly cooled in order to dissolve Zr, Fe, Mg, and Cu (solution treatment). In this case, the alloy material may be an ingot or a hot or cold worked material. In other words, the present invention aims to obtain a conductor with the target excellent performance by cold working after solution treatment, and the material before solution treatment has approximately the same performance whether it is an ingot or a processed material. can get. If the solution treatment temperature is lower than 500°C, no improvement in strength or heat resistance will be observed due to the small amount of solid solution, and if it is higher than 645°C, no further improvement will be observed, and the melting temperature Because they are so close together, manufacturing work becomes difficult. Note that air cooling or water cooling may be used as a means for rapidly cooling after this solution treatment. As mentioned above, the reason for heating at 500 to 645℃, rapid cooling, and then cold processing to reduce the area by 65% or more is to increase the strength through work hardening and subsequent heat treatment. The reason for reducing the surface area by more than 65% is because if it is less than 65%, the strength will be low. After cold working in the method () of the present invention,
Heat treatment at 250 to 450℃ for 1 to 400 hours is to improve precipitation hardening and conductivity due to aging, and if this treatment is lower than 250℃ or within the temperature range of 250 to 400℃, it is shorter than 1 hour. If the temperature is higher than 400°C or longer than 400 hours, the strength decreases due to the over-aging phenomenon and the heat resistance deteriorates. In the method () of the present invention, in the method ()
The reason why we divide the heat treatment process into two stages when heat treating a material whose area has been reduced by more than 65% is to promote the formation of fine precipitates and make precipitation hardening even more pronounced. The rate and strength are further improved. The reason why the first step was to be heat treated at 200 to 400℃ for 1 to 400 hours is because if the temperature is less than 200℃ or the heating time is less than 1 hour, the effect will not be achieved, and if the temperature is higher than 400℃, the strength will decrease. Also, heating for longer than 400 hours does not produce a greater effect and is uneconomical. Also, during the second stage of heating, the first
Heating at a temperature 30°C or more higher than the first stage is to grow the ultrafine precipitates or precipitation nuclei formed in the first stage, and below 30°C there is no effect and there is no difference from simply heating continuously. do not have. Furthermore, if the temperature is less than 250°C or the heating time is less than 1 hour, the growth of fine precipitates is slow and no improvement in electrical conductivity or strength is observed. Also, if heated at a temperature higher than 500°C or for a longer time than 400 hours, the precipitates will become coarse and both strength and heat resistance will decrease. In addition, when carrying out the method () of the present invention, 560~
After heating at 630℃, rapidly cool it, reduce the area by more than 80% in the cold, and then heat it at 300~350℃ for 70~
A conductor with excellent performance can be obtained by heat treatment for 150 hours. In addition, in carrying out the method () of the present invention, when performing heat treatment after cold working of the material manufactured within the above condition range, the first step is heated at 300 to 400 ° C. for 2 to 100 hours, and the second step is performed. Moreover, the temperature is 50 to 100℃ higher.
Conductors with better performance can be obtained by heating in the temperature range of 380-450°C for 20-100 hours. Next, the present invention will be explained in detail with reference to examples. Example Mainly using electrical aluminum ingots with a purity of 99.85 to 99.95% and melting them, Al-6% Fe master alloy, Al-20% Si master alloy, Al-50% Cu master alloy, Al
-5% Zr master alloy, Al-5% Be master alloy, Al-5%
Al alloys of various compositions were melted using Sb master alloy and Mg alone, and by adding Mitsushi metal as a rare earth element. Furthermore, as rare earth elements (RE), rare earth elements such as lanthanum, cerium, and yttrium all exhibit the same additive effect, so they exhibit exactly the same effect when added individually or when two or more types are added together. ,
It may be added as Mitsushi metal. These alloys were cast into a mold of 25 x 25 x 400 mm and then rolled into rough drawn wires with a diameter of 8 to 12 mm. After heating this to a temperature of 480 to 645℃, it is cooled with water.
60.9~91.5% wire drawing process and further 0.5~ at 200~450℃
Heat treated for 500 hours. In addition, when heat treatment is performed in two stages after cold working, the first stage is heated at 180 to 490°C.
0.5-500 hours, second stage at 230-550℃ for 0.5-500 hours
Heat treated for hours. In addition, 99.95% aluminum base metal was used for those with Fe addition amount of 0.08% or less. In any case, the amount of Fe, Si, etc. added was calculated by subtracting the amount contained in the base metal as an impurity from the blend value. The tensile strength, electrical conductivity, and heat resistance of the samples thus produced were measured. The tensile strength was determined using an Instron type tester, and the electrical conductivity was determined by measuring electrical resistance using a Kelvin double bridge. Heat resistance was determined by heating the sample at 350°C for 1 hour and expressing the ratio of the tensile strength after heating to the tensile strength before heating. Table 1 shows these alloy compositions, manufacturing conditions, and performances.

【table】

[Table] Examples Nos. 1 to 10 were manufactured by the method () of the present invention, and the tensile strength was 23 Kg/mm ² or more and the electrical conductivity was 58
It showed excellent performance with %IACS or higher and heat resistance of 98% or higher. Example Nos. 11 and 15 were manufactured by the method () of the present invention, and had excellent performance with a tensile strength of 25.5 to 27.4 Kg/mm ² , electrical conductivity of 59% IACS or higher, and heat resistance of 94% or higher. have. Next, Comparative Examples Nos. 16 to 30 were manufactured under processing and heat treatment conditions according to the method of the present invention, but their alloy compositions were outside the range specified by the present invention. That is, Nos. 16 to 29 were manufactured according to the method in (), but No. 16 had low strength and heat resistance due to the small amount of Zr, and No. 17 had low conductivity due to the excessive amount of Zr. Not only that, but the heat resistance is also low. Nos. 18 and 19 have an inappropriate amount of Fe, and Nos. 20 and 21 have an inappropriate amount of Si, so high performance cannot be obtained. Nos. 22, 25, and 26 have insufficient amounts of added Mg, Cu, Sb, Be, RE, etc., and Nos. 23, 24, 27, 28, and 29 have excessive amounts of each of the above elements, resulting in tensile strength. It cannot exhibit excellent performance in all three properties: electrical conductivity, heat resistance, and electrical conductivity. or
No. 30 was manufactured according to the method in (), but high performance was not obtained in either case because the alloy compositions such as Si, Mg, Cu, Sb, and Be were outside the range. Next, Comparative Examples Nos. 31 to 45 are examples in which the alloy composition is within the range, but the manufacturing conditions are different from () to (). No. 31 has a low solution treatment temperature of 480℃, No. 32 has a wire drawing processing rate of 60.9%, which is lower than the conditions in method (), and Nos. 33 to 36 have a low heating temperature after wire drawing. High performance cannot be obtained because the conditions are different. In No. 37, the heating temperature in the second stage after wire drawing was lower than that in the first stage, so the effect of heat treatment in two stages was not recognized, and in this case also, the product was manufactured using method (). There's no big difference. No. 38 also had a low heating temperature in the first stage, and No. 40 had a short heating time, so the effect of the two-stage heat treatment was not significant. No. 39 has poor strength because the heating temperature after wire drawing is too high.
Heat resistance will decrease. No. 41 has too long heating time in the first stage, so No.
Nos. 42 and 43 have inappropriate second-stage heating temperatures.
For 44 and 45, the second stage heating time is inappropriate, respectively.
In either case, it is not possible to produce a conductor that is excellent in all three properties of strength, electrical conductivity, and heat resistance. Next, Table 2 shows the performance of Comparative Examples Nos. 48 to 49 produced by the conventional spreading method. In the case of this rolling method, a 25 x 25 x 400 mm ingot was produced in the same manner as in the previous example, heated at 450°C for 1 hour, and then hot rolled to form a rough drawing wire of 9.5 mmφ. Wire drawing was performed with an area reduction rate of 82.3 to 91.5%. As a result of measuring the performance of this material, it was found that the material manufactured by the conventional method had high strength, but low electrical conductivity, and especially extremely poor heat resistance.

[Table] As explained above, by manufacturing an alloy within the composition range specified in the method of the present invention according to the methods () to () specified in the present invention,
A conductor that is excellent in all three properties of heat resistance can be obtained.

Claims (1)

[Claims] 1 Zr0.15-0.8wt%, Fe0.05-0.6wt%, Si0.04
Contains ~0.20wt%, and Mg0.005~0.5wt%,
Cu0.005~0.5wt%, rare earth elements 0.01~0.5wt%,
An alloy material containing one or more elements of 0.005 to 0.1 wt% Sb and 0.005 to 0.1 wt% Be, and consisting of residual Al and normal impurities is heated at 500 to 645°C. A method for producing a high-strength, heat-resistant aluminum alloy conductor, which is characterized in that the conductor is rapidly cooled, subjected to cold processing to reduce its area by 65% or more, and then heat-treated at 250 to 400°C for 1 to 400 hours. 2 Zr0.15-0.8wt%, Fe0.05-0.6wt%, Si0.04
Contains ~0.20wt%, and Mg0.005~0.5wt%,
Cu0.005~0.5wt%, rare earth elements 0.01~0.5wt%,
Contains one or more elements of Sb0.005-0.1wt% and Be0.005-0.01wt%, with the remainder Al
and normal impurities at 500 to 645℃.
After heating with
After the above area reduction processing, the heat treatment process is divided into two stages, the first stage is heat treatment at 200 to 400 °C for 1 to 400 hours, and the second stage is at a temperature 30 °C or more higher than the first stage. 1 to within the temperature range of 250 to 500℃
A method for manufacturing high-strength, heat-resistant aluminum alloy conductors that undergoes heat treatment for 400 hours.