JPH036215B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a heat-resistant aluminum alloy for conductive use and a method for manufacturing the same. In particular, the present invention relates to a heat-resistant aluminum alloy for conductive use and a method for manufacturing the same. In particular, it has strength equivalent to that of conventional heat-resistant aluminum alloy for conductive use (Al-Zr alloy), and has heat resistance without significantly reducing conductivity. This is an improvement. Conventionally, steel-core aluminum stranded wires with conductors made of electrical grade Al have been used for overhead power transmission lines, and transmission lines that require particularly high heat resistance have utilized the heat resistance mechanism of solid solution Zr in Al-Zr alloys. A steel-core heat-resistant aluminum alloy stranded wire using a conductor made of a solid solution type heat-resistant aluminum alloy has been used, but in recent years there has been a demand for improved heat resistance due to increased demand for electric power. In response to this, a heat-resistant conductive aluminum alloy with an increased amount of solid solution Zr and a conductive heat-resistant aluminum alloy that utilizes the heat resistance mechanism of precipitated Zr instead of the heat resistance mechanism of solid solution Zr have been developed. However, an increase in the amount of solid solution Zr leads to a decrease in electrical conductivity, and in order to take advantage of the heat resistance mechanism of precipitated Zr, long-term heat treatment is required at a temperature of 300 to 450°C, resulting in high costs. It was hot. In addition, the usable heating temperature of these alloys when energized is about 300°C, and there is a strong desire to improve their heat resistance to withstand even higher temperatures. In view of this, as a result of various studies, the present invention has been developed as a conductive material that has strength equivalent to that of conventional conductive heat-resistant aluminum alloys (Al-Zr alloys) and has far superior heat resistance without significantly reducing conductivity. The company has developed a heat-resistant aluminum alloy and its manufacturing method. That is, the alloy of the present invention contains 1.5 to 6 wt% Ni (hereinafter wt% is simply abbreviated as %), 0.02 to 0.3% Cu, and 0.03 to 0.5% Be.
, with the balance consisting of Al and normal impurities. In addition, the manufacturing method of the present invention has Ni1.5 to 6% and Cu0.02 to 0.3%.
%, Be 0.03 to 0.5%, and the balance Al and normal impurities is continuously or semi-continuously cast, and after cold drawing into hot-rolled rough drawn wire, 200 to 500 It is characterized by heat treatment at a temperature of 0.5 to 10 hours. However, the reason why the alloy composition is limited as described above in the present invention is as follows. The reason for limiting the Ni content to 1.5 to 6% is to improve the strength and heat resistance as a eutectic structure in which _NiAl3 is dispersed in the Al matrix by adding Ni. However, if the Ni content is less than 1.5%, If it exceeds 6%, the dendrite phase of primary NiAl ₃ crystallizes in the alloy structure, which not only impairs workability but also reduces ductility. The reason for limiting the Cu content to 0.02 to 0.3% is that although the strength and heat resistance are improved by dispersing _NiAl3 by adding Ni, the strength is insufficient because the Al matrix is pure Al. This strengthens the Al matrix and improves its strength.
This is because when the Cu content is less than 0.02%, the effect is insufficient, and when it exceeds 0.3%, the conductivity decreases significantly. In addition, the Be content was limited to 0.03 to 0.5%.
This is to improve the corrosion resistance of the alloy by adding Be, but if the Be content is less than 0.03%, the effect will be small, and if it exceeds 0.5%, the electrical conductivity will decrease significantly. Other impurities are impurities that are unavoidably included in ordinary Al metal for electrical use, and
As long as it is contained in the Al base metal, the properties of the alloy of the present invention will not be impaired in any way. The alloy of the present invention has the above composition and is cast by conventional continuous or semi-continuous casting, followed by hot rolling to form a rough drawn wire. This is then cold drawn to the desired wire diameter, and then drawn at a temperature of 200 to 500℃ to a
Produced by heat treatment for a period of time. 0.5 at a temperature of 200-500℃ after cold wire drawing
The reason for the heat treatment for ~10 hours is to adjust the strength and conductivity as well as impart heat resistance.
If the temperature is below 200℃, the conductivity will not recover, and if the temperature exceeds 500℃, the strength will decrease significantly, and the processing time will be 0.5℃.
If the heating time is less than 15 hours, the conductivity and heat resistance will not recover, and if the heating time exceeds 15 hours, the strength will decrease significantly. The present invention will be described in detail below with reference to examples.
99.8% purity electrical Al ingot and Al−10%Ni, Al−
Using each mother alloy of 50% Cu and Al-5% Be, alloys having the compositions shown in Table 1 were mixed and melted. This was cast using a belt-and-wheel type continuous casting machine, and the obtained ingot was immediately hot rolled into a rough wire having a diameter of 9.5 mm. This is cold wire drawn to a diameter of 4.5mm.
After making wire rods, they were heat-treated at various temperatures, and their electrical conductivity, tensile strength, heat resistance, and corrosion resistance were measured. The results are compared with a wire rod made of a conventional conductive heat-resistant aluminum alloy (Al-Zr alloy) and are also listed in Table 1. The electrical conductivity was calculated by measuring resistance using a Kelvin double bridge, and the tensile strength was measured using an Amsler type tester. Further, heat resistance was expressed as the heating temperature at which the tensile strength decreased by 10% after 1 hour of heat treatment, and corrosion resistance was expressed as the weight loss rate after conducting a 5% NaCl spray test for 100 days.

【table】

[Table] As is clear from Table 1, the alloys of the present invention manufactured based on the method of the present invention (Nos. 1 to 5) have a high electrical conductivity.
56.2% IACS or higher, tensile strength 17.0Kg/mm ² , heat resistance
It exhibits properties of 390°C or higher and corrosion resistance of 0.7% or less, and compared to conventional method No. 16, it has almost the same electrical conductivity, tensile strength, and corrosion resistance, and is far superior in heat resistance. On the other hand, as can be seen from Comparative Method Nos. 6 to 11, alloys outside the composition range of the present invention alloys are inferior in electrical conductivity, tensile strength, heat resistance, and corrosion resistance even if produced by the present invention method. In other words, comparative method No. 6 with low Ni content
Comparative method No. 7, which has poor heat resistance and high Ni content,
Comparative method No. 9, which has a high Cu content, and Comparative method No. 11, which has a high Be content, both have inferior conductivity, and Comparative method No. 8, which has a low Cu content, has inferior tensile strength.
Comparative method No. 10, which has a low content, has poor corrosion resistance. Furthermore, as can be seen from Comparative Methods Nos. 12 to 15, even if the alloy is within the composition range of the invention alloy, if the heat treatment conditions after cold wire drawing are outside the range, the electrical conductivity, tensile strength, and heat resistance are inferior. . In other words, comparative method No. 12, which uses a lower heating temperature, has inferior conductivity, while comparative method No. 12, which uses a higher heating temperature, has inferior conductivity.
No. 13 has inferior tensile strength. Comparative method No. 14, which requires a short heat treatment time, is inferior in all of electrical conductivity, tensile strength, and heat resistance, and comparative method No. 15, which requires a long treatment time, is inferior in tensile strength. As described above, if the alloy of the present invention is manufactured based on the method of the present invention, it will have almost the same electrical conductivity and tensile strength as the conventional heat-resistant aluminum alloy for conductive use (Al-Zr alloy), and it will have much superior strength. It provides heat resistance and has a remarkable effect in that it can be used for power transmission lines and the like to increase the size of power transmission containers.

Claims (1)

[Claims] 1 Ni1.5~6wt%, Cu0.02~0.3wt%, Be0.03~
A heat-resistant aluminum alloy for conductive use that contains 0.5wt% and the balance is Al and normal impurities. 2 Ni1.5~6wt%, Cu0.02~0.3wt%, Be0.03~
After continuously or semi-continuously casting an aluminum alloy containing 0.5wt% and the balance Al and normal impurities, and cold drawing it into a hot-rolled rough drawn wire,
A method for producing a heat-resistant aluminum alloy for conductive use, characterized by heat treatment at a temperature of 200 to 500°C for 0.5 to 10 hours.