JPH0215625B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a conductive heat-resistant aluminum alloy wire (hereinafter abbreviated as aluminum alloy wire) having excellent heat resistance and conductivity. Traditionally, Al has been used as a heat-resistant aluminum alloy for conductive use.
By adding a small amount of Zr and using a manufacturing method in which Zr is dissolved as a solid solution during the manufacturing process, an aluminum alloy wire with excellent heat resistance and conductivity has been obtained (for example, the patent
842110, 842111). This type of conductive heat-resistant aluminum alloy wire is known as 60% heat-resistant aluminum alloy wire (60TAl), and its conductivity is 60% IACS or higher, and its heat resistance has a continuous operating temperature of 150%.
It has the characteristics of ℃. In recent years, there has been a strong desire to further improve the heat resistance of conductive heat-resistant aluminum alloy wires and increase the current carrying capacity of wires of the same size. The present invention was obtained as a result of studies conducted by the present inventors on various alloys and manufacturing methods in order to further improve the above-mentioned heat resistance.
By applying a special processing and heat treatment process to Al-Zr alloy, the conductivity is 60%, the same as 60TAl.
The purpose is to provide a heat-resistant aluminum alloy wire for conductive use that has significantly superior heat resistance and is better than IACS. The present invention includes Zr0.15-0.35%, Fe0.05-0.5%,
When continuously casting and rolling a molten alloy containing 0.03 to 0.25% Si and the balance Al and normal impurities, casting is performed at a pouring temperature of 710 to 750°C, and the rolling start temperature is 540 to 580°C. , followed by cold working with an area reduction rate of 50% or more, and then 300~500
By applying aging treatment at ℃ for 5 to 200 hours and then cold working with an area reduction rate of 35% or more, it has an electrical conductivity of 60% IACS or more, a strength equivalent to hard aluminum wire, and a wire that lasts for 1 hour. This is a method for producing a heat-resistant aluminum alloy wire for conductive use, which is characterized by having a 10% softening temperature of 300°C or higher when heated. Here, the 10% softening temperature means the lowest heating temperature at which the tensile strength decreases by 10% after heating for 1 hour. In the present invention, the Zr content is specified as 0.15 to 0.35% because if it is less than 0.15%, the heat resistance is insufficient.
This is because if it exceeds 0.35%, coarsening of precipitates occurs, and as the amount of Zr increases, heat resistance deteriorates and costs also increase. In addition, the reason why the amount of Fe is specified as 0.05 to 0.5% is that if it is less than 0.05%, the strength of the drawn wire will be low and it will not be effective in shortening the aging time, and if it exceeds 0.5%, the electrical conductivity and heat resistance will decrease. It is from. Also, the amount of Si was specified as 0.03% to 0.25%, which is 0.03%.
If it is less than 0.25%, not only will the cost of the metal increase increase, but it will not be effective in shortening the aging time, and if it exceeds 0.25%, casting cracks will be noticeable and the heat resistance will also decrease. Next, in the present invention, continuous casting and rolling of the molten alloy can be carried out using a casting machine consisting of an endless belt and a rotary casting wheel, such as the Propelch method or the SCR method, or a Hezlett method.
A combination of a casting machine such as the 3C method and a rolling mill that performs continuous hot rolling is used. According to such a continuous casting and rolling method, the Zr that is forcibly dissolved in the solid solution during casting is brought to the hot rolling process without precipitating, so that it precipitates uniformly and finely as Al ₃ Zr during the subsequent aging treatment. , can significantly improve heat resistance. For example, ^the solidification conditions during casting are as follows:
By casting within the range of 5.0 to 7.0 ton/hr and using cooling conditions that allow the hot rolling start temperature to be 530°C or higher, an alloy with the desired performance can be obtained. Next, in the present invention, the temperature of the molten metal immediately before the casting machine (casting temperature) is preferably 700°C or higher. The reason for this is that when the Zr concentration is high as in the present invention, when the casting temperature is lower than 700℃, Zr crystallizes in the form of coarse particles in the form of Al ₃ Zr, and the heat resistance becomes poor in the added Zr. This is because not only the effective amount decreases, but also the crystallized coarse particles lower the heat resistance. In addition, the temperature of the ingot immediately before the hot rolling mill (rolling start temperature) is preferably 530°C or higher;
If it is less than that, heat resistance will deteriorate. If the outside temperature, casting conditions, etc. are below 530°C, the ingot is heated after leaving the casting machine and before entering the rolling mill. In the present invention, cold working with an area reduction rate of 50% or more after continuous casting and rolling is performed in order to obtain heat resistance of 300°C or more (10% softening temperature) by combining with the subsequent aging treatment. It is also intended to improve electrical conductivity. This cold working is
It has a very large effect on improving heat resistance.
In cold working, the larger the area reduction rate, the better the heat resistance. For example, by giving an area reduction of about 69% and then adjusting the aging conditions appropriately, the heat resistance shows an extremely high value of 358°C at the 10% softening temperature, but if the area reduction is less than 50%, During processing, a 10% softening temperature of 300°C or higher cannot be achieved no matter what kind of aging treatment is performed afterwards. At the same time, the cold working with an area reduction of 50% or more also produces good results on the electrical conductivity of the wire, and the higher the area reduction, the better the electrical conductivity. Even if the area reduction rate is less than 50%, a slight improvement in conductivity can be expected, but no effective improvement can be expected. Since heat resistance and electrical conductivity must be satisfied at the same time, the present invention specifies the area reduction rate of the cold working as 50% or more. Next, in the present invention, the aging treatment conditions after the cold working are specified as 5 to 200 hours at 300 to 500°C, because this heat treatment allows Zr to precipitate uniformly and finely as Al ₃ Zr, improving electrical conductivity. This is to improve heat resistance through dispersion strengthening by finely precipitated Al ₃ Zr. At temperatures below 300°C, the heat treatment time becomes longer and productivity is hindered, and at temperatures above 500°C, precipitates form. This is because the particles become coarse and the heat resistance deteriorates. Temperature and time in aging treatment are correlated as optimal conditions; the higher the temperature, the shorter the time. The aging conditions are optimal, and the 10% softening temperature after heating for 1 hour can be 330°C or higher. In addition, after the final aging treatment, cold working with an area reduction of 35% or more is required because in order to have the same strength as hard aluminum wire, cold working with an area reduction of 35% or more is required. This is because if it is less than %, the desired strength cannot be obtained. The aging process here is divided into several times,
Surface reduction processing may also be included in between. However, from the point of view of industrial production, one aging treatment is desirable. In addition, the aluminum ingot used as a raw material in the present invention may be an ordinary electric aluminum ingot, but in order to prevent deterioration of heat resistance, the impurities contained in the aluminum ingot should be kept as small as possible. It is desirable to suppress it. By configuring the present invention as described above,
Heat resistance can be increased to a 10% softening temperature of 300℃ or higher by heating for 1 hour, which corresponds to a continuous use temperature of 210℃,
It has high heat resistance with a short-term usage temperature of about 260℃,
In addition, it has an electrical conductivity of 60% IACS or higher, a strength equivalent to that of hard aluminum wire, and the temperature and time range of aging treatment is wide, so it can be manufactured stably and easily. The present invention will be explained below using examples. Example 1 Zr, Fe, and Si in the amounts shown in Table 1 were added to electrical aluminum ingot (JISH2110) containing ordinary impurities, and after degassing treatment, a mold with a cross-sectional area of 3200
A cast rod was obtained by continuous casting using a rotating wheel trial casting machine of mm ² , and then continuously hot rolled to obtain a cast rod of 11.7 mm.
A rough line of mmφ was obtained. In this case, the temperature of the molten metal (casting temperature) immediately before the casting machine was 720 to 750°C, and the temperature of the cast rod immediately before the rolling machine (rolling start temperature) was 550 to 570°C. Next, the rough drawing line is cold worked (referred to as processing),
Aging treatment (referred to as treatment) and cold working (referred to as processing) were performed under the conditions shown in Table 1. Tensile strength and conductivity of the obtained aluminum alloy wire, 10
The % softening temperatures are shown in Table 1.

[Table] From Table 1, Nos. 1 to 10 according to the present invention have the same tensile strength as the hard aluminum wire (No. 11) and the electrical conductivity.
It can be seen that it has an IACS of 60% or higher and a 10% softening temperature of 300°C or higher. On the other hand, in the comparative example outside the composition range of the present invention, No. 1 containing a large amount of Si.
15 and No. 16 cause casting cracks and cannot be cast continuously, and other Nos. 12 to 14, 17, and 18 cannot be obtained that satisfy all of the tensile strength, conductivity, and heat resistance. I couldn't help it. Example 2 An aluminum alloy having the same composition as No. 8 shown in Table 1 was continuously cast and rolled in the same manner as in Example 1 to obtain a rough wire of 11.7 mmφ. However, the casting temperature was 710 to 740°C, and the rolling start temperature was 540 to 580°C. Next, the rough drawn wire was subjected to the processing, treatment, and processing shown in Example 1 under the conditions shown in Tables 2 and 3, respectively. The 10% softening temperature or tensile strength of the obtained aluminum alloy wire is as shown in Tables 2 and 3.

【table】

[Table] The effect of the area reduction rate of processing on the 10% softening temperature shown in Table 2 shows that Nos. 19 to 24 according to the present invention have no effect on the 10% softening temperature.
It shows a temperature of 300°C or more, but the comparative example with an area reduction rate of less than 50% does not reach 300°C. Regarding the effect of the area reduction rate of processing on the tensile strength shown in Table 3, Nos. 28 to 33 according to the present invention can obtain a tensile strength of 17 Kg/mm ² or more, but a comparative example with an area reduction rate of less than 35% has a tensile strength of 17 kg/mm 2 or more.
It was found that it did not reach Kg/mm ² . As described above, the aluminum alloy wire produced by the manufacturing method of the present invention has Zr0.15-0.35%, Fe0.05-0.5%,
Contains 0.03 to 0.25% Si, the balance consists of Al and normal impurities, and the molten alloy is continuously cast and rolled.
The Zr that was forced into solid solution during casting is dissolved without precipitation, and after continuous casting and rolling, cold working is performed with an area reduction rate of 50% or more, and then aging treatment is performed at 300 to 500℃ for 5 to 200 hours. Therefore, when the above cold working is combined with _aging treatment, improvements in electrical conductivity and heat resistance can be obtained at the same time. After treatment, we perform cold working with an area reduction rate of 35% or more, so the desired strength can be obtained, resulting in a conductivity of 60%.
It has the advantage of having strength equal to or higher than IACS and equivalent to hard aluminum wire, and excellent heat resistance with a 10% softening temperature of 300°C or higher after heating for one hour. Furthermore, since the aging treatment has a wide temperature and time range, it has the advantage that stable heat resistance performance can be easily produced.

Claims (1)

[Claims] 1 Zr0.15~0.35%, Fe0.05~0.5%, Si0.03~
When continuous casting and rolling is performed from a molten alloy containing 0.25% Al and the balance Al and normal impurities, the casting temperature is set to 710 to 750℃, and the rolling start temperature is
Conducted at 540-580℃, and then reduced area by 50
% or more cold working, then 500°C at 300~500°C.
After ~200 hours of aging treatment, the area reduction rate is 35.
By applying cold working of 60% or more, the electrical conductivity can be increased to 60%.
A method for manufacturing a heat-resistant aluminum alloy wire for conductive use, which has a strength equal to or higher than IACS and a hard aluminum wire, and has a 10% softening temperature of 300°C or higher when heated for one hour.