JPS607703B2 - Manufacturing method of heat-resistant aluminum alloy conductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a heat-resistant aluminum alloy conductor based on A-Zr-Fe. By performing a combination of cold rolling and heat treatment, the heat resistance of the conductor is improved.

In recent years, with the increase in power transmission capacity, steel-core heat-resistant aluminum alloy stranded wires have been used in overhead power transmission lines, but under special power transmission conditions, better heat-resistant aluminum alloy conductors are needed to further increase power transmission capacity. ``Many heat-resistant aluminum alloys for conductive use have been researched.

However, what is currently in practical use is an A-Zr alloy containing Zr as an active ingredient.

Although the heat resistance of this alloy increases depending on the amount of Zr added, the electrical conductivity decreases. Therefore, in order to further increase heat resistance, Zr
If the amount is increased, the conductivity will drop significantly, making it impractical for practical use. In view of this, the present invention has developed a method for manufacturing a heat-resistant aluminum alloy conductor that can improve the heat resistance of the conductor without significantly lowering the conductivity, as a result of various studies on A-Zr alloys.

That is, the present invention is based on Zro. 15-0. Sakaki t% (hereinafter wt%
is simply written as %), Feo. 05-0.6%, Sio.
04-0.3%, and Mg0.002-0.5%
, Cuo. In the production of heat-resistant aluminum alloy conductors, an alloy containing one or both of 002 and 0.5% and the remainder A and ordinary impurities is continuously cast and rolled into a rough wire, which is then cold-worked. A molten alloy of 740 to 95 qC is placed in a mold heated to 80 to 200 q C to create a 0. is solidified and continuously cast at a cooling rate of 0/sec or more, and rolling is started at a temperature of 550 oo or less while continuing to cool the obtained mirror block at a rate of 6000/min or more,
Before finishing the rolling at a temperature of 35,000 or less, the area is reduced by 40% or more to obtain a rough wire. One of the inventions is
After heat-treating this rough drawing wire, cold processing is applied to reduce the area by 65% or more.
A method of treating for 1 to 40 field hours at a temperature of 100°F (IA method), or a heat treatment for 1 to 40 field hours at a temperature of 200 to 400°C, and then at a temperature of 3 degrees or more higher than the nuclear treatment temperature.
Moreover, it is a method (IB method) in which heat treatment is performed for 1 to 400 hours within a temperature range of 250 to 55 pi.

Another aspect of the present invention is to heat-treat the rough-drawn wire, then apply cold processing to reduce the area by 65% or more, and then further heat-treat the wire at a temperature of 250 to 500 qo. A method of processing for 1 to 40 hours at a temperature of 250 to 450 degrees, followed by cold processing for 1 to 400 hours at a temperature of 250 to 450 degrees (the method of secretion), or a method of reducing the surface by 65% or more at a temperature of 250 to 450 degrees. Either or both of the heat treatment before and after adding
Heat treatment at a temperature of ~40,000 °C for 1 to 400 hours, and then at a temperature of 30oo or more higher than the treatment temperature, and at a temperature of 250 °C.
This is a method of heating the bait for 1 to 40 hours within a temperature range of ~55,000 °C (Hi's method).

In the present invention, the alloy composition is limited as described above for the following reasons. Zr is added to improve strength and heat resistance, and the content should be adjusted from 0.15 to
The reason why it is set at 0.8% is that if the content is less than 0.15%, the strength and heat resistance will be insufficient, and if the content exceeds 0.8%, the effect of improving strength and heat resistance will be saturated, and the conductivity will decrease. This is because the decrease becomes significant. Fe, like Zr, is added to improve strength and heat resistance, and its content should be adjusted from 0.05 to
The reason why it is set at 0.6% is because if the content is less than 0.05%, the effect will be small, and if the content exceeds 0.6%, no further improvement in strength and heat resistance will be observed, and the conductivity will decrease. be.
The purpose of adding Si is to improve the strength, and the reason why the content is 0.04 to 0.3% is because the content is 0.04%.
This is because the strength is low when the content is full, and the conductivity decreases when it exceeds 0.3%. Furthermore, Mg and/or Cu are added to improve strength, and the content of these is reduced to 0.
．． The reason for setting the content to 0.002 to 0.5% is that if the content is less than the lower limit, there is no effect of improving strength, and if the content exceeds the upper limit, the conductivity will decrease significantly.

In carrying out the present invention, Zro. 15-0. class t%
, Fe o. 05-0.6%, Sio. 04-0.3%
and Mg0.002-0.5%, Cuo. 00
A conductor with particularly excellent performance can be obtained by using an alloy composition containing 2 to 0.5% of one or both of them, and the remainder A and other ordinary impurities.

Next, the casting and rolling conditions for continuous casting and rolling of the alloy in the above composition range were specified as above in order to forcibly drop Zr and Fe among the alloy components during casting, and to prevent them from precipitating as they are. This is to improve the strength, electrical conductivity, and heat resistance by bringing the hot-rolled material to room temperature and heat-treating it before and/or after the lining processing to finely precipitate Zr and Fe.

Therefore, the temperature of the mold (casting wheel and belt in the case of a regular belt-and-wheel type continuous casting machine) is specified to be 80 to 200°C.The reason is that if the temperature is lower than 80q○, the surface of the Zenitama in contact with the mold will be cooled too much. , the surface of the coin coin shrinks after solidification, forming an air gap, which slows down the cooling rate of the coin coin as a whole, making it ineffective for the strength melting of Zr and Fe.Also, when the mold temperature is higher than 20,000℃, the mold and coin This is because the temperature gradient of the lump becomes smaller, the cooling rate becomes slower, and the forced collective melting of Zr and Fe becomes ineffective.

In addition, the temperature of the molten metal poured was set at 740 to 950 qo in order to solidify it with a steep temperature gradient.
If it is lower than 950°C, the temperature gradient will be small and the amount of forced solidification of Zr and Fe will be small, and if it is higher than 950°C, the oxidation of the molten metal surface will be intense and a good quality coin coin will not be obtained due to the entrainment of oxides etc. , and because there is a large difference in the solidification rate between the surface and the center of the coin coin, Zr and Fe segregate and their concentrations differ between the surface and the center of the coin coin, making it impossible to obtain a product with excellent performance. .

Next, molten metal of 740 to 950 oo is poured into a mold heated to 80 to 20,000 ℃. The reason for solidifying at a cooling rate of 0/sec or more is to force Zr and Fe into solid solution, and this cooling rate is usually controlled by water cooling the casting wheel and belt.

This water cooling is insufficient and the cooling rate is 0. This is because if it is slower than 0/sec, Zr and Fe cannot be forcibly dissolved into solid solution, and if water cooling is too intense, an air gap is created between the mold and the mirror block, which slows down the cooling rate. Must be carefully controlled. Rolling the thus obtained coin block while cooling it at a speed of 6000/min or higher is necessary to forcibly dissolve Zr and Fe into a solid solution.
This is to prevent the precipitation of
If the temperature is slower than in, precipitation of Zr and Fe will occur.

Also, rolling was started at a temperature of 550q○ or less, and rolling was started at a temperature of 350q.
Adding surface reduction processing of 40% or more before finishing rolling at the following temperature prevents Zr and Fe from precipitating during rolling, destroys the casting structure, and prevents forced solidification during solidification. This is to crush and refine the coarse crystallized phases of Zr and Fe that are partially crystallized in order to obtain a uniformly dispersed rolling mass. If the rolling start temperature is higher than 550 pm and the rolling end temperature is higher than 350 pm, forced solid solution Zr and Fe will precipitate, and if the area reduction rate is less than 40%, the casting assembly will deteriorate. The destruction of the microstructure is insufficient, and coarse crystallized substances remain in the structure, reducing strength and heat resistance. By continuously casting and rolling the alloy under the above conditions, a rough drawn wire in which Zr and Fe are forced into a solid solution can be obtained.

The reason why the above-mentioned rough drawn wire is heat-treated by the IA method of the present invention and then subjected to cold area reduction processing is to improve the strength and conductivity through age hardening by heat treatment, and to greatly increase the work hardening ability in the subsequent cold working. The purpose of this is to improve the strength, electrical conductivity, and heat resistance by cold working this.The reason why the heat treatment is 250 to 500 qo and 1 to 40 feeding hours is because the processing temperature is lower than 250 °C or 250 qo. ~500q
Even within the temperature range of 0, if the treatment time is shorter than 1 hour, the aging effect will not appear, and if the treatment temperature is higher than 50,030 or the treatment time is longer than 40, the strength will decrease due to the over-aging phenomenon. .

In addition, the area reduction rate in cold working was set to 65% or more because
This is because if the surface loss rate is less than 65%, sufficient work hardening will not be obtained, and not only the strength but also the heat resistance and electrical conductivity will decrease. The reason why the rough drawn wire is further heat treated after the cold working in the IA method of the present invention is to further improve the heat resistance and conductivity by age hardening, and the heat treatment is performed at 250 to 250°C. The processing temperature is lower than 250do or 250 to 45 at 450qo.
Even within the temperature range of 450°C, no improvement in heat resistance and conductivity was observed if the treatment time was shorter than 1 hour.
This is because if the treatment time is higher than qo or the treatment time is longer than 40 cycles, the strength and conductivity will decrease due to the over-aging phenomenon.

In addition, the heat treatment steps before and after cold working in methods IA and 2A of the present invention are divided into two stages, and the first stage is 200 to 400 qo.
The IB and spot treatment methods of the present invention include heating for a period of 1 to 40 degrees at a temperature in the second stage at a temperature of 250 to 550 degrees Celsius or more at a temperature higher than the first stage by at least 30 minutes. By dividing the treatment process into two stages, the formation of fine precipitates is promoted to make the precipitation effect even more pronounced, thereby further improving the electrical conductivity and strength.

However, the reason why the first stage was specified as 200 to 40,000 for 1 to 400 hours was because the effect was not recognized at 200 qo or 1 hour, and the strength decreased at temperatures higher than 400 ℃. Even if the food is heated for a longer time than the feeding time, no greater effect is observed and it is uneconomical. In addition, during the second stage heating, heating is performed at a temperature 30q0 or more higher than the first stage treatment temperature in order to grow the ultrafine precipitates or precipitation nuclei formed in the first stage.
If it is less than that, there is no effect and there is no difference from simply heating continuously. Also, the second stage is 1 to 4 with 250 to 550 qo.
00 hours is defined as the growth of fine precipitates is slow at temperatures below 250°C or treatment for less than 1 hour, and no improvement in conductivity and strength is observed.
This is because if the treatment is longer than the zero-field time, the precipitates will become coarser and both strength and heat resistance will decrease. As described above, according to the method of the present invention, it is possible to obtain a conductor with excellent strength, electrical conductivity, and heat resistance. o. 10
~0.40%, Si 0.006~0.20%,
and Mg0.05-0.20%, Cuo. 05-0.2
In the production of a heat-resistant aluminum alloy conductor obtained by continuous casting and rolling of an alloy consisting of 0.0% and the remainder of
150oo, cooling rate during solidification 0.5-100qo/
sec, and the coin coins are heated at 150 to 300℃/m.
Rolling is started at a temperature of 400 to 500 qo while cooling at a cooling rate of 1.5 in, and the surface is reduced by 60% or more, and rolled to a rough drawing line with a temperature of 300 to 150 qo at the end of rolling. , the area reduction rate during cold working is 75~
97%, and each heat treatment before and after cold processing was
Divided into stages, the first step is at 300-400°C for 2-2 hours, then at a temperature 50-100°C higher than the processing temperature of the first stage, and within the temperature range of 380-450oo for 2-2 hours.
Feed time treatment yields conductors with even better performance.

Hereinafter, the present invention will be explained with reference to examples.

(Example) Electrical A metal with a purity of 99.8% was melted, and to this was added A-5% Zr, A-6% Fe, A-20% Si, and A-50% Cu. A-Z by adding each mother alloy and Mg alone
An r-Fe alloy was melt-tempered and cast and rolled under various conditions using a belt-and-wheel continuous casting and rolling mill to form rough wires.

Table 1 shows the alloy composition and manufacturing conditions of the rough wire. Furthermore, Fe
, electrical grade A metal with a purity of 99.9% was used to melt the Si-poor alloy. Table 1 In Table 1, A is pouring overflow (00), B is mold temperature (00)
, C is the cooling rate during casting (g○/sec), D is the rolling start temperature (°C), E is the rolling end temperature (00), F is the cooling temperature during rolling (°C/min), and G is the rolling reduction rate. shows.

Also, in Table 1, enemies for the present invention. Nos. 1 to 10 are rough drawn wires formed using alloy compositions specified in the present invention under casting conditions and rolling conditions specified in the present invention, and No. 1 for comparison. Nos. 11 to 17 are rough drawn wires formed under the casting conditions and rolling conditions specified in the present invention, which differ from the alloy composition specified in the present invention.

Furthermore, No. for comparison. Reference numerals 18 to 21 indicate rough drawn wires obtained by casting and rolling alloy compositions specified in the present invention under conditions other than the casting conditions and/or rolling conditions specified in the present invention. The cooling rate during solidification is adjusted by adjusting the casting speed (rotational speed in casting theory), the amount of water flowing to the casting wheel and belt, which are water-cooled molds, and the water temperature. The cooling rate was controlled using a continuous rolling mill that was equipped with a cooling device and could freely control the rolling temperature.

[11] Using a part of the rough drawn wire shown in Table 1 formed in this way, it was heat-treated under the conditions shown in Table 2 according to the IA method of the present invention, and then subjected to wire drawing processing to form a conductor. was manufactured.

The tensile strength, electrical conductivity, and heat resistance of these conductors were measured. The results are also listed in Table 2. The tensile strength was measured using an Instron type tester, and the electrical conductivity was determined by measuring electrical resistance using a Kelvin double bridge. Moreover, heat resistance was determined by heating each sample at a temperature of 270° C. for 1 hour and expressing the ratio (%) of the tensile strength before and after the heat treatment. Second
As is clear from Tables 1 and 2, methods 1 to 5 of the present invention
The tensile strength of all conductors manufactured by
It can be seen that high characteristics such as leg 2 or higher, electrical conductivity of 59.6% IACS or higher, and heat resistance of 92.2% or higher can be obtained.

On the other hand, in Comparative Methods 6 to 11, in which the rough wire forming conditions are different from those of the present invention, any one or more of the properties of tensile strength, dew conductivity, and heat resistance are decreased, and the rough wire forming conditions are different from those of the present invention. Even if the conditions are the same, it can be seen that at least one of tensile strength, electrical conductivity, and heat resistance is decreased in Comparison *Methods 12 to 14, which are different from the heating conditions or cold working conditions specified in the present invention.

'21 A conductor was manufactured by using a portion of the rough drawn wire shown in Table 1 above and subjecting it to heat treatment, cold working, and heat treatment under the conditions shown in Table 3 according to the method of the present invention. The conductor characteristics of these conductors were measured in the same manner as in Example 1. The results are also listed in Table 3. The heat resistance was determined by heating each sample at a temperature of 300 am for 1 hour and expressing the ratio (%) of the tensile strength before and after the heat treatment. As is clear from Table 3, Tables 1 and 3, methods of the present invention 15-
The tensile strength of all conductors manufactured by No. 19 is 17.6k.
9/Yanagi 2 It can be seen that high characteristics such as electrical conductivity of 59.5% IACS or higher and heat resistance of 91.0% or higher can be obtained.

On the other hand, in Comparative Methods 20 to 24, in which the conditions for forming the rough wire are different from those of the present invention, any one or more of the properties of tensile strength, electrical conductivity, and heat resistance are decreased, and the conditions for forming the rough wire are different from those of the present invention. It can be seen that even if the values are the same, any one or more of tensile strength, electrical conductivity, and heat resistance is decreased in Comparative Methods 25 to 27, which deviate from the heating conditions or processing conditions specified in the present invention.

{31 Using a part of the rough lines shown in Table 1 above, cold working after two-stage heat treatment under the conditions of Table 4 according to the IB and wave methods of the present invention, and before and after cold working. A conductor was manufactured by a method in which one or both of the subsequent heat treatments were performed in two stages.

The conductor characteristics of these conductors were measured using the same machine as in Example 1. The results are also listed in Table 4. Regarding heat resistance, in Table 4, methods 28 to 30 of the present invention and comparative method 34 were heated at a temperature of 270 am for 1 hour, and expressed as the ratio (%) of the tensile strength before and after heating.

*Additionally, methods 31 to 3 of the present invention
3 and comparative method 35 were heated at a temperature of 300° C. for 1 hour and expressed as the ratio (%) of the tensile strength before and after heating. Table 4 As is clear from Tables 1 and 4, the method of the present invention 28
Samples No. 30 to 30 were heat treated in two stages before cold working, and when compared with Example 1 and Table 2, it can be seen that higher performance can be obtained.

On the other hand, in Comparative Example 34, the heating conditions were different from those of the method of the present invention, so the performance was inferior.

Methods 31 to 33 of the present invention are those in which either or both of the heat treatments before and after cold working are performed in two stages, and all have higher performance compared to Example 2 and Table 3. It turns out that you can get it.

On the other hand, in Comparative Method 35, the heating conditions were different from those of the method of the present invention, so the performance was lower. As described above, according to the present invention, a conductor with excellent tensile strength, electrical conductivity, and heat resistance can be manufactured by specifying the composition range of the alloy, processing conditions such as casting conditions, rolling conditions, and heating conditions. This has a remarkable industrial effect.

Claims (1)

[Claims] 1 Zp0.15-0.8wt%, Fe0.05-0.
6 wt%, Si0.04 to 0.3 wt%, and M
g0.002~0.5wt%, Cu0.002~0.5
Continuous casting and rolling of an alloy containing one or both of wt% and the balance consisting of Al and normal impurities to form a rough wire,
In the production of heat-resistant aluminum alloy conductors that undergo cold working, 740~200℃ is placed in a mold heated to 80~200℃
Molten alloy at 950°C is poured and solidified at a cooling rate of 0.2°C/sec or more for continuous casting, and the resulting ingot is continuously cooled to 550°C while cooling at a rate of 60°C/min or more.
Rolling is started at a temperature below, and while finishing rolling at a temperature below 350°C, an area reduction of 40% or more is applied to create a rough drawn wire, which is then heat treated and then cold rolled to reduce an area of 65% or more. A method for manufacturing a heat-resistant aluminum alloy conductor, which is characterized by adding processing. 2. The method for manufacturing a heat-resistant aluminum alloy conductor according to claim 1, wherein the rough drawn wire is heat treated at a temperature of 250 to 500°C for 1 to 400 hours, and then cold processed to reduce the area by 65% or more. 3 After heat-treating the rough wire at a temperature of 200-400°C for 1-400 hours, and then heat-treating it at a temperature 30°C or more higher than the treatment temperature and within a temperature range of 250-550°C for 1-400 hours. 2. The method for producing a heat-resistant aluminum alloy conductor according to claim 1, wherein the conductor is subjected to cold processing to reduce its area by 65% or more. 4 Zr0.15~0.8tw%, Fe0.05~0.
6 wt%, Si0.04 to 0.3 wt%, and M
g0.002~0.5wt%, Cu0.002~0.5
Continuous casting and rolling of an alloy containing one or both of wt% and the balance consisting of Al and normal impurities to form a rough wire,
In the production of heat-resistant aluminum alloy conductors that undergo cold working, 740~200℃ is placed in a mold heated to 80~200℃
Molten alloy at 950°C is poured and solidified at a cooling rate of 0.2°C/sec or more for continuous casting, and the resulting ingot is continuously cooled to 550°C while cooling at a rate of 60°C/min or more.
Starting rolling at a temperature below, and finishing rolling at a temperature below 350°C, an area reduction of 40% or more is applied to create a rough drawing wire, which is heat treated, resulting in an area reduction of 65% or more in cold rolling. A method for producing a heat-resistant aluminum alloy conductor, which comprises further applying heat treatment after processing. 5 A patent for heat-treating a rough wire at a temperature of 250-500°C for 1-400 hours, then cold processing to reduce the area by 65% or more, and then heat-treating it at a temperature of 250-450°C for 1-400 hours. A method for manufacturing a heat-resistant aluminum alloy conductor according to claim 4. 6 Heat treatment at a temperature of 200 to 400°C for 1 to 400 hours before and after cold processing to reduce the area by 65% or more, and then heat treatment at a temperature of 30°C above the processing temperature.
Claim 4: The heat treatment is performed at a temperature higher than ℃ and moreover within a temperature range of 250 to 550℃ for 1 to 400 hours.
A method for producing a heat-resistant aluminum alloy conductor as described in 1.