JPS61243159A - Production of heat resistant aluminum alloy conductor having high electric conductivity - Google Patents

Abstract

PURPOSE:To obtain a conductor having superior electric conductivity and heat resistance by hot rolling and clad working an Al alloy contg. restricted amounts of Zr, Fe and Si under regulated conditions. CONSTITUTION:The Al alloy consisting of, by weight, 0.005-0.05% Zr, 0.05-0.2% Fe, <=0.07% Si and the balance Al with ordinary impurities is continuously cast. The cast alloy is hot rolled at 450-600 deg.C, rapidly cooled at once to <=200 deg.C and continuously hot rolled at <=200 deg.C. The resulting rough wire is cold rolled down and >=60% reduction of area. By this method, the conductor having superior electric conductivity and heat resistance can be obtd. without reducing the strength.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a highly conductive heat-resistant aluminum alloy conductor, and in particular, it relates to a method for producing a highly conductive heat-resistant aluminum alloy conductor, and in particular, it has a tensile strength equivalent to that of conventional heat-resistant aluminum alloy conductors and superior heat resistance and conductivity. The purpose is to manufacture a conductor having the following characteristics.

[Prior art] Generally, overhead power transmission lines are made of electrical aluminum ingot (J
An aluminum conductor made from 15H2110) with a conductivity of 62% 1AC3 or higher is used. However, it is necessary to limit the short-time use temperature of this conductor to 100° C. or less, and the strength of the conductor cannot be guaranteed above this temperature. For this reason, when heat resistance is required, 0.06 wt% Zr is added to the electrical aluminum base metal.
A heat-resistant aluminum alloy conductor is used.

This conductor can be used at temperatures up to 180°C for a short period of time, and can guarantee heat resistance (tensile strength retention rate) of 90% at 230°C for 1 hour.

[Problems to be Solved by the Invention] Since the conductivity of the heat-resistant aluminum alloy conductor is as low as about 60%, improvement thereof is strongly desired.

In other words, the electrical conductivity and heat resistance of a conductor are determined by the amount of lr contained, so in order to improve the electrical conductivity, it is necessary to reduce the amount of Zr contained, but on the other hand, reducing the amount of Zr contained has the disadvantage that heat resistance decreases. There is.

[Means for Solving the Problems] In view of this, as a result of various studies, the present invention has developed a high-temperature aluminum alloy that has almost the same tensile strength as conventional heat-resistant aluminum alloys, superior heat resistance, and far superior electrical conductivity. A method for manufacturing conductive heat-resistant aluminum alloy conductors has been developed, and Z r 0
．． 005~0,05 wt%, l"eO105~0,2
wt%, S i O, 07 wt% or less, the balance A (and normal impurities) is continuously cast, followed by hot rolling to form a rough wire, and cold working to form a conductor. , 450-6 for the first half of hot rolling
After being heated to 00°C, it is immediately quenched to 200°C or below, and then the latter half is continuously rolled at 200°C or below to form a rough drawn wire, which is then cold-rolled to reduce the area by 60% or more. It is something to do.

[Function] The reason why the alloy composition is limited as described above in the present invention is as follows.

Z is an additive element to improve heat resistance, and if its content is less than 0.005wt%, sufficient heat resistance cannot be obtained, and if it exceeds o,os wt%, the electrical conductivity will decrease significantly. .Fe is an additive element to improve strength and further improve heat resistance, and its content is o, o
If it is less than s wt%, sufficient strength and heat resistance cannot be obtained, and 0
, 2 wt%, the conductivity decreases significantly. Further, 3i is contained as an impurity, and since it lowers the conductivity, it is desirable to have a small amount, and the content is limited to 0.07 wt% or less.

In the process of continuously casting an alloy with such a composition, then hot rolling it into rough drawn wire, and cold working it to make a conductor, the first half of hot rolling is carried out at 450 to 600°C. This is to ensure sufficient solid solution of Zr and Fe. If the first half of hot rolling is less than 450°C, the amount of solid solution of Zr and Fe will be insufficient, and if it exceeds 600°C, hot rolling cracks will occur and the steel will not be healthy. I can't get a conductor. The reason for rapidly cooling to below 200°C immediately after the first half hot rolling is to keep the temperature below the precipitation temperature without causing solid solution Z and solid solution Fe to precipitate. Above 200°C, precipitation of Fe occurs and heat resistance decreases. The reason why the second half is continuously rolled at 200°C or less is to prevent the precipitation of solid solution Fe and to improve the strength.
The purpose of reducing the area by 0% or more is to increase the strength of the conductor, and if the degree of processing is less than 60%, sufficient strength cannot be obtained.

[Example] An aluminum base metal with a purity of 99.8% was melted, and zirconium potassium fluoride (Zr content 30 wt%) A, e
-6wt% Fe master alloy, AJ! -10 wt% 3i master alloy was added to produce an alloy having the composition shown in Table 1, and a cross-sectional area of 2000 Ia2 was produced using a belt-and-wheel continuous casting machine.
This was continuously cast into an ingot, which was subsequently rolled in a hot rolling mill under the conditions shown in Table 2 to obtain a rough wire having a diameter of 9.5 mm. A heating burner was attached to each roll stand of the hot rolling mill for heating, and for cooling, the flow rate and temperature of the cooling tank and rolling oil were adjusted.

Next, the rough drawn wire was cold drawn to produce a conductor, and the electrical conductivity, tensile strength, and heat resistance of the conductor were measured, and the results are shown in Table 3. The tensile strength was measured using an Instron type tensile tester, and the electrical conductivity was determined by measuring electrical resistance using a Kelvin double bridge. The heat resistance was determined by measuring the tensile strength of the conductor after heating it at 230° C. for 1 hour, and expressed as a percentage of the tensile strength before heating.

Table 1 Alloy composition by alloy (wt%) B
O,0100,090,06#G 0901
B 0.18 0.04 IID O
,0270,140,05,##E
00037 0.10 0.05 #F
O,0440,080,05#II G
O, 0390, 160, 04N comparative alloy
HO,0010,150,05#1 0.08
0.10 0.05,.

J O,0310,020,04//K
O,0280,250,05#L O,0380
,160,09〃Conventional alloy M 0005
0.20 0.13 #Table 2 Manufacturing method No. Alloy First half hot rolling Temperature after quenching Second half rolling temperature Cold working rate symbol Temperature ('C)
(”C) (’C) (%
) Method of the present invention 1A480-470 150
15shi~130 66.52 B 475
~580 185 185~150 7
4,53 C51 540 165 16
5-150 80,54 0 560-500
145 145-125 74,55E
575-460 140 140-130
86.46F560~550 160
160-145 86.47 G 52 to 5
40 155 155-145 80.
5 comparative method 88480-530 155
155-140 74,59151 5(9)
150 15F Episode 1 Marshal, 5”
10J 575-480 140 14
()-12574,5〃 5ω to 11 ~ 520
165 165~140 86.4#
121 480-520 15
5 155-135 74.5n
13B 400-430 120
12 To 115 B6.44# 14G
380~470 135 135~12
5 86.4II 15 E 56 625 195 195-150 74
．． 5# 16F 620~550 19
0 1 to 180 74.5#17A480~
520 250 195-140 80.
5n 18E 510-540 195
220~180 74,5# 19
F 530-570 195 225~
205 80.5〃 20C520~540
175 175-140 53.2 Conventional method 21 M
74.5 Table 3 3 61.2 17.6 93.4 4 61.4 17.4 92.6 5 61.3 17.8 92.8 6 61.5 17.6 92.6 7 61.2 17.8 94.1 Comparative method 8 62.4 17.0
88.19 60.3 17.4 93.2 10 61.3 15.9 88.41160゜0
18.2 91.8 12 60.5 17.5 92.113 61.5
17.6 89.014 61.2 17.4
89.215 59.9 16.4 91.416
59.9 16.3 92.217 61.9 1
7.4 88.918 61.4 17.0 88.
619 61.6 17.7 89.020 61.
3 15.4 91.4 Conventional method 21 60
．． 4 17.4 90.6 As is clear from Tables 1 to 3, the conductors manufactured by the methods NQ1 to 7 of the present invention have a tensile strength of 16.9 to 17.8 Kg/am2 and a heat resistance of 91.3. ~94.1%, electrical conductivity of 61% lAC3 or higher, and compared to the conductor manufactured by the conventional method 21, the tensile strength is almost the same, but the heat resistance and electrical conductivity are far superior. I know that there is.

On the other hand, in Comparative Methods Nos. 8 to 12, which fall outside the alloy composition range specified by the method of the present invention, and Comparative Methods No. 13 to 20, in which the manufacturing conditions deviate from the specified range even if the alloy composition is within the specified range,
It can be seen that all of them are inferior in one or more of electrical conductivity, tensile strength, and heat resistance. That is, Comparative Process No. 8, which has a low Zr content, has poor heat resistance, Comparative Process NC19, which has a high Zr content, has low conductivity, and Comparative Process NQ10, which has a low Fe content, has low strength and poor heat resistance. Comparative method No. 11, which has a high 3i content, has a low conductivity, and comparative method No. 12, which has a high 3i content, also has a low conductivity.Also, even if the alloy composition is within the range of the alloy composition regulated by the method of the present invention, the conductivity is low. Comparative method NQ1 with low temperature
Comparative method NQ15.16 has poor heat resistance and high hot rolling temperature in 3.14, which has low conductivity and tensile strength due to wire surface defects due to hot rolling cracks in the ingot, and the temperature after quenching is low. It can be seen that the comparative method N1117, which has a high temperature, has poor heat resistance, the comparative method 11, which has a high re-rolling temperature, and the comparative method 118.19, which has a low heat resistance, and the comparative method 1k120, which has a low area reduction in cold rolling, has a low tensile strength.

[Effects of the Invention] As described above, according to the present invention, it is possible to manufacture a conductor that has strength equivalent to that of conventional heat-resistant aluminum alloy conductors and far superior conductivity and heat resistance, and overhead power transmission lines using this conductor can be manufactured. This has significant industrial effects, such as being able to increase power transmission capacity.

Claims (1)

[Claims] Zr0.005~0.05wt%, Fe0.05~0.
2wt% Si, 0.07wt% or less of Si, the balance Al and normal impurities are continuously cast, followed by hot rolling to form a rough wire, which is then cold worked into a conductor. 450-60 for the first half of rolling
After being heated at 0℃, it is immediately quenched to 200℃ or less, and then the second half is continuously rolled at 200℃ or less to form a rough drawn wire, which is then subjected to a cold area reduction process of 60% or more. A method for producing highly conductive, heat-resistant aluminum alloy conductors.