JPS59107067A - Production of heat resistant aluminum alloy conductor - Google Patents

Abstract

PURPOSE:To produce a heat resistant aluminum alloy conductor having excellent strength and conductivity by subjecting a roughly drawn wire consisting of an aluminum alloy having a specific compsn. contg. Zr, Fe and Si to an aging heat treatment and further to an adequate heat treatment. CONSTITUTION:An aluminum alloy contg. 0.15-0.8wt% Zr, 0.05-0.8% Fe, and 0.04-0.5% Si and consisting of the balance Al and ordinary impurities is continuously or semicontinuously cast and rolled to a roughly drawn wire wherein Zr is uniformly solubilized. The roughtly drawn wire is cold worked to improve strength. The wire is subjected to an aging heat treatment before or after the cold working to deposit uniformly and finely Zr and is further subjected to a heating treatment for 0.5-20hr at the temp. lower than the aging heat treatment in a temp. range of 200-350 deg.C to deposit uniformly and finely Fe and Si, whereby the heat resistant aluminum alloy conductor having improve conductivity without decreasing strength and heat resistance is obtd. The above-mentioned aging heat treatment is accomplished preferably by two stages of aging heat treatments or by heating for 5-200hr at 250-450 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides Al-7r-
This invention relates to a method for manufacturing a heat-resistant aluminum alloy conductor made of Fe-3i alloy, and in particular improves conductivity without impairing the strength and heat resistance of the conductor.

Conventionally, copper-core aluminum stranded wires, in which a conductive aluminum conductor is twisted around a copper core, have been used for overhead power transmission lines.In cases where heat resistance is particularly required, a heat-resistant aluminum alloy conductor made of △1-7r alloy is used with a copper core. Heat-resistant aluminum alloy strands twisted around the core are used. However, in recent years, due to land shortages for power transmission lines and increasing power demand, there has been a need for long-diameter power transmission, and Fe and Sl have been added to A12R alloy to improve its strength and heat resistance. conductor was developed. Although this alloy had improved heat resistance due to the solid solution of Zr, and improved strength due to the addition of e and Si, it had the disadvantage of poor electrical conductivity.

In recent years, instead of Ahzr-based conductors that utilize the heat resistance mechanism of solid solution Zr, heat-treated type Δ conductors that utilize the heat resistance mechanism of precipitated Zr have been developed.
1-7r series conductors were developed. This conductor is made by continuous or semi-continuous casting and rolling, and is made of a rough drawn wire containing Zr as a solid solution, before or after cold working, at high temperature and for a long time, for example, 3
Aging heat treated at 50℃ for 100 hours to finely and uniformly disperse and precipitate 7r, which has a conductivity of 58%lAC3.
or more, or 60% lAC3 or more conductor is 1q. However, in order to make a conductor with excellent conductivity,
high temperature.

Since long-term heat treatment is required, Zr precipitation occurs in a so-called over-aged state, resulting in a disadvantage that the strength and heat resistance are lower than IIc. Heat it to a relatively low temperature to spread it out! A so-called two-stage aging heat treatment has been proposed in which the fine and uniform precipitation of 7R is completed in a short time by heating at a high temperature afterwards. However, in this method, C was also unable to prevent a decrease in the strength and heat resistance of the conductor.

In view of this, as a result of various tests, the present invention has found that by precipitating Fe and Si together with the precipitation of 7r, the conductivity can be improved without impairing the strength and heat resistance of the conductor. A method for manufacturing a heat-resistant aluminum alloy conductor with excellent properties has been developed.
8 Wj%, FeO,05~0,8W[%,3i0
．． A method for producing a conductor, in which an aluminum alloy containing 04 to 0.5 wt% and the balance △1 and normal impurities is made into a rough wire by continuous or semi-continuous casting and rolling, and the wire is subjected to aging heat treatment before or after cold working. After the aging heat treatment, a heat treatment is performed for 0.5 to 20 hours at a temperature lower than the aging heat treatment within a temperature range of 200 to 350''C.

However, in the present invention, the reason why the alloy composition is limited as described above is as follows.

That is, Zr is added to improve the strength and heat resistance of the conductor, and its content is 0.15 wt%.
(Hereinafter, wt% is simply abbreviated as %) If it is less than 0.8%, sufficient strength and heat resistance cannot be obtained, and if it exceeds 0.8%, the effect of improving strength and heat resistance will be saturated, but the conductivity will be significantly reduced. It's for a reason. Fe is added to improve the strength of conductors, but if its content is less than 0.05%, its effect is small, and if it exceeds 0.8%, not only the strength improvement effect is saturated, but also the conductivity This is because the decrease in f4 becomes more significant.

In addition, Si is added to improve the strength of the conductor, promote the precipitation of J3L and 7R during aging heat treatment, and accelerate recovery of conductivity, or its content is 0.0
If the ir content is less than 4%, not only will sufficient strength not be obtained, but the effect of promoting 7r precipitation will be small, and if it exceeds 0.5%, the conductivity will be significantly lowered. In the present invention, d5 is ZrO, 25 to 0.5%.

FeO, 1-0.4%, 3i 0.06-0.
By using an aluminum alloy containing 2% and the remainder Δ1 and ordinary impurities, it is possible to produce a conductor with particularly excellent performance.

The present invention casts and hot-rolls an alloy having the composition ffG as described above by continuous or semi-continuous casting and rolling to obtain a rough drawn wire in which 7r is uniformly dissolved in solid solution, which is subjected to aging heat treatment before or after cold working. Then, 7r is uniformly and finely precipitated, and this is subjected to aging heat treatment within a temperature range of 200 to 350°C and heat treatment at a low temperature for 0.5 to 20 hours. is uniformly and finely precipitated to improve conductivity without impairing the strength and heat resistance of the conductor.

However, by continuous or semi-continuous casting and rolling, 7"
In order to remove the rough wire that forms a solid solution, it is desirable that the pouring temperature during casting be 750° C. or higher.

In addition, aging heat treatment includes heat treatment at a high temperature for a long time or heat treatment at a relatively low temperature, followed by high temperature C heat treatment.
Stage aging treatment is used, and in particular, in order to prevent overaging of 7R precipitation, 5 to 200
It is desirable to perform aging heat treatment for a period of time. The reason for this is that even if the heating temperature is less than 250℃ or the heating period is less than 5 hours, Z
The precipitation of r is insufficient and no improvement in conductivity can be expected, and even if the heating temperature exceeds 450°C or the heating time exceeds 200 hours, the precipitated 7r becomes coarse or overaged, resulting in poor heat resistance and strength. This is because it is low.

In addition, the reason why the heat treatment after the aging heat treatment is performed at a temperature lower than the aging heat treatment within the temperature range of 200 to 350 °C for 0.5 to 20 hours is to precipitate Fe and 3i in an equilibrium state by the aging heat treatment. When the heat treatment temperature is higher than the aging heat treatment temperature, Fe and 3i dissolve into solid solution, reducing the conductivity. Furthermore, even if the heating temperature is less than 200°C or the heating time is less than 0.5 hours, Fe The amount of precipitated Si and Sl is small, and no improvement in conductivity can be expected, and if the heating humidity exceeds 350°C, Fe and Sl will re-dissolve, resulting in poor conductivity (1
This is because (I), if the heating time exceeds 20 hours, the precipitation of Fe and Sl will be almost saturated, and recovery of the conductivity beyond failure cannot be expected, and on the contrary, the heat resistance will decrease.

In addition, in the present invention, cold working is performed before or after the aging heat treatment and heat treatment in order to increase the strength of the container. , cold working to reduce the area by 60% or more, and aging heat treatment (including 2-stage 04 effect heat treatment) to 300~4
It is desirable to carry out the heat treatment at a temperature of 250 to 320'C for 40 to 100 hours, and then carry out the subsequent heat treatment at a temperature of 250 to 320'C/1 to 8 hours.

Examples of Kikomei will be described in detail below.

An alloy having the composition shown in Table 1 was melted using a 1li99.8% electric A1 ingot, potassium zirconium oxide (Kz Zr Fs), a Δ1-6% Fe-red alloy, and a Δ1-20% S1 master alloy. It was cast and rolled using a Bell 1-and-boil type continuous casting and rolling mill to form a rough wire having a diameter of 9.5 mm. The pouring temperature during casting was 750 to 830'C.

The rough drawn wire C-formed in this way is subjected to aging heat treatment as shown in Table 2, followed by heat treatment, and subjected to area reduction processing not shown in Table 2 using a continuous wire drawing machine to produce a conductor. did.

The electrical conductivity, tensile strength, and heat resistance of this conductor were measured. The results are shown in Table 2 (71).The electrical conductivity was determined by determining the electrical resistance using a Kelvin tuple bridge.
The tensile strength was measured using an Ins 1-ron type testing machine. In addition, heat resistance is determined by heat-treating the conductor at a temperature of 270°C for 1 hour.
It was determined from the ratio of the tensile strength before and after the treatment.

Table 1 Mn n Q7 n □------C □ Table 2 [・As is clear from Table 1 and Table F2, the present invention method N02
The conductors manufactured by the conventional method NO, 23
24, it can be seen that the conductivity is much improved without deteriorating the tensile strength and heat resistance.

In contrast, to comparative method No. 11 using alloys 11 to M which fall outside the metal composition range defined by the method of the present invention.
8 and Comparative method N in which the heat treatment conditions after aging heat treatment are different even if the alloy composition is within the range specified by the method of the present invention.
It can be seen that between 0.19 and 22, either the conductivity 1 strength or the heat resistance is decreased.

Example (2) An alloy having the composition shown in Table 1 was melted in the same manner as in Example (1), and continuously cast in the same manner.

It was made into a rough wire by hot rolling. This is not shown in Table 13, but was subjected to cold area reduction processing using a strip A'↑, subjected to aging heat treatment, and then heat treated to produce a conductor.

Regarding this conductor, conductivity was determined in the same manner as in Example <1).
Tensile strength and heat resistance were measured. The results are shown in Table 3.
I wrote 1.

Regarding heat resistance, the conductor can be heated to 420°C and 370"
The specimen was heat-treated at a temperature of C for 1 hour, and the tensile strength after the treatment was determined.

As is clear from Tables 1 and 3, the method of the present invention N O
, 25-32 has a conductivity of 6()%.
If fAcsJy is above, the heat resistance at a heating temperature of 370°C is 93.6% or more, and the electrical conductivity is 58.7 to 59.
5%1 to AC8, the heat resistance to a heating temperature of 420°C is 94.2% or more, and conventional method N
o.

It can be seen that the conductivity is far superior to that of the conductors manufactured in Nos. 43 and 44.

On the other hand, even those within the alloy composition range defined by the alloy composition range J defined by the present invention, comparative methods No. 33 to 38 using the dislocated base metals 1 to M, and the alloy composition range defined by the method of the present invention, Comparison method No. 3 with different heat treatment conditions after heat treatment
9 to 42 have conductivity similar to Example (1).

It can be seen that either strength or heat resistance is inferior.

As described above, according to the method of the present invention, a highly conductive conductor can be manufactured without impairing heat resistance.
It is used for long-diameter twisted wires for power transmission, etc., and exhibits a νr1 effect.

-1J Nishiben Yamaj Ching Calendar jl (/j style) April 27, 1981, Special Edition Agency Waka], Shapeless [Iji (pressure 1, ヱJ+l'l indication 1111 sum) 571+', 4 views 1 condyle No. 2148; U3 No. 2, Name of defense of heat-resistant aluminum alloy η body!!AI"j1] Method 3, Relationship with n6iil-+!i, IIl 1" I revision applicant 11 place
21-6-1 Marunouchi, Chiyoda-ku, Tokyo Name
(529) Furukawa Electric Industry Co., Ltd. (Meeting L4, agent address Kami 1, Chiyoda-ku, Tokyo)] 16N Kitajomonocho
Address: 101, Building 3rd Floor, 5th, day of correction order

Claims (1)

[Claims] (l) 7. r 0015~0.8 Wj%, "
O0005~0.8wt%Si0.04~0.5w
In a conductor manufacturing method in which an aluminum alloy containing t% and the balance AI and normal impurities is made into a rough wire by continuous or semi-continuous VJ forming and subjected to cold working or aging heat treatment after working, aging heat treatment is performed. Go 200-3
0.5 to a temperature lower than aging heat treatment within the temperature range of 50℃
A method for producing a heat-resistant aluminum alloy conductor, the method comprising heat-treating for ~20 hours. (2) The method for producing a heat-resistant aluminum alloy conductor according to claim 1, wherein a two-stage aging heat treatment is performed as the aging heat treatment. (3) Aging heat treatment at a temperature of C250-450℃ for 5~
A method for manufacturing a heat-resistant aluminum alloy conductor according to claim 1, wherein the conductor is heated for 200@.