WO2023093131A1

WO2023093131A1 - Super-heat-resistant aluminum alloy wire and preparation method therefor

Info

Publication number: WO2023093131A1
Application number: PCT/CN2022/111772
Authority: WO
Inventors: 赵立洋; 张桓; 乔恒; 段妍彤; 张佳辉
Original assignee: 江苏亨通电力特种导线有限公司
Priority date: 2021-11-25
Filing date: 2022-08-11
Publication date: 2023-06-01
Also published as: CN114086033A; CN114086033B

Abstract

A super-heat-resistant aluminum alloy wire and a preparation method therefor. The super-heat-resistant aluminum alloy wire is composed of the following components in percentage by weight: Si: 0.18-0.22%, Mg: 0.21-0.23%, Fe: 0.10-0.15%, Zr: 0.48-0.52%, Y: 0.04-0.08%, less than 0.005% of Cr, Mn, V, and Ti in total, and the balance being Al and other inevitable impurities. An aluminum rod obtained by refining, secondary refining, removing impurities, casting, and rolling is subjected to two-stage heat treatment, cold drawing, and aging treatment, so as to obtain a final finished product, i.e., the super-heat-resistant aluminum alloy wire.

Description

A kind of super heat-resistant aluminum alloy wire and its preparation method

technical field

The invention belongs to the field of alloy materials, and in particular relates to a super heat-resistant aluminum alloy wire and a preparation method thereof.

Background technique

With the rapid development of the economy and the improvement of living standards, the demand for electricity has increased sharply, and the transmission lines have gradually developed in the direction of large capacity, which leads to the need to increase the transmission capacity of the wire. As a special wire with excellent performance, heat-resistant aluminum alloy has advantages in urban network capacity expansion and reconstruction, substation construction and lines. The heat-resistant conductor is to increase the allowable temperature of the conductor appropriately, which can increase the stable current carrying capacity of the system in case of accidents, and is used to increase the transmission capacity of the line. Through the research, it is found that adding metal zirconium (Zr) element in the aluminum material can improve the heat resistance of the aluminum material, which directly affects and leads to the production of the heat-resistant aluminum alloy stranded wire with steel core. The wire has technical characteristics such as high temperature resistance and large transmission capacity. However, there are also disadvantages such as increased loss of the line, increased sag, and high cost of the wire during high-temperature operation, which affects its application on long-distance transmission lines.

The super heat-resistant aluminum alloy wire can operate at 210°C for a long time, and the short-term temperature can reach 240°C, which greatly improves the carrying capacity and greatly reduces the loss in the power transmission process, and has been greatly developed, but At present, most of the super heat-resistant aluminum alloy wires can only achieve the electrical conductivity of the single wire between 60.0-60.5%IACS, the tensile strength between 160-170MPa and the heat resistance between 160-170MPa under the premise of ensuring heat resistance. Between 91%-95%. Low strength, large cross-sectional area of overhead wires, large sag, limited spanning distance of wires, poor electrical conductivity, high energy consumption, high electrical loss, easy segregation of Zr elements, uneven precipitation, coarse grains after heat treatment, and due to Zr The elements are easy to be distributed unevenly, and the rate of grain growth is different, and the grain size is uneven again.

Contents of the invention

In order to solve the above technical problems, the present invention aims to provide a super heat-resistant aluminum alloy wire and a preparation method thereof. Its conductivity is ≥61.5%, and its tensile strength is ≥250MPa.

The invention provides a super heat-resistant aluminum alloy wire, which is composed of the following components in weight percentage: Si: 0.18-0.22%, Mg: 0.21-0.23%, Fe: 0.10-0.15%, Zr: 0.48-0.52%, Y : 0.04-0.08%, and the total amount of Cr, Mn, V and Ti is less than 0.005%, and the balance is Al and other unavoidable impurities.

The present invention also provides a method for preparing a super heat-resistant aluminum alloy wire according to claim 1, comprising the following steps:

(1) Melt the aluminum alloy, add AlB ₃ to react, add sodium-removing refining agent (Jinlianxing, GFLUX-J185), and refine to obtain molten aluminum A;

(2) Add AlSi20, AlFe20, Mg, AlY10 and AlZr10 to the aluminum liquid A, stir for 30-35min, add a sodium-removing refining agent, perform secondary refining, and remove impurities to obtain aluminum liquid B;

(3) Casting, rolling, and double-stage heat treatment are performed on the molten aluminum B to obtain a super heat-resistant aluminum alloy rod;

(4) cold drawing the super heat-resistant aluminum alloy rod, and obtaining the super heat-resistant aluminum alloy wire after aging treatment.

Preferably, in the step (1), the purity of the aluminum alloy is not less than 99.85%.

Preferably, in the step (1), the melting temperature is 780-800° C.; the mass ratio of aluminum alloy to AlB ₃ is 1000:1-5. Said refining is passed into a protective atmosphere and left to stand for 40-50 minutes at a temperature of 780-800°C.

Preferably, in the step (2), 7-9kg, 1-2kg, 2-3kg, 5-7kg and 40-60kg of AlSi20, AlFe20, Mg, AlY10 and AlZr10 are added per ton of aluminum alloy respectively.

Preferably, in the step (2), the secondary refining is carried out in a furnace for 20-30 minutes, standing still for 30-40 minutes, and the temperature is 780-800°C.

Preferably, in the step (3), the casting temperature is 670-680°C, the casting speed is 7.0-7.5t/h, the cooling water temperature is 25-35°C, and the billet discharge temperature is 520-550°C.

Preferably, in the step (3), during the rolling process, the rolling temperature is 510-540°C, and the finishing rolling temperature is 200-300°C.

Further, the two-stage heat treatment is to cool down to room temperature (25±5°C), raise the temperature to 590-620°C for 7-8h, and keep it for 15-20h; The cooling rate of ℃/s quickly cools down to room temperature (25±5℃).

Further, in the step (4), the deformation amount of each cold drawing is 20-40%, and after 8-12 passes, the deformation is 2.8-3.6mm.

Further, the aging treatment is to raise the temperature to 180-200° C. for 1-2 hours, and keep the temperature for 10-30 hours.

Through aging treatment, the precipitation of Mg and Si elements is promoted, thereby reducing the resistance; at the same time, the Mg2Si phase is formed to achieve the purpose of increasing the strength.

Compared with the prior art, the technical solution of the present invention has the following advantages:

1. Sodium element is easy to form eutectic with low melting point, and it is easy to melt during high-temperature annealing process to cause structural defects, which affects material properties. Therefore, sodium-removing refining agents are introduced in the present invention to remove sodium in the ingredients.

2. Through low-temperature casting, increase the supercooling degree in the crystallization process to achieve the purpose of refining grains.

3. By using heat treatment to precipitate Al3Zr, the strength can be improved while reducing the resistance. Mg and Si elements can form Mg2Si phase to improve the matrix strength. At the same time, Si elements can promote the precipitation of Zr elements and reduce the occurrence of segregation. Fe elements It can improve the creep resistance of the material, and the rare earth element Y can purify the matrix, reduce pores and impurities, refine the grains, and promote the precipitation of various elements.

4. Through two-stage annealing and heat treatment at 590-620°C, Si, Mg, and Zr elements can be fully dissolved in the gold matrix, and at the same time promote uniform organization. After 440-470°C heat treatment, the Zr in the matrix can be dissolved The precipitation of elements is reduced, and the precipitation of Si and Mg elements is prevented by rapid cooling.

5. Through the aging treatment of monofilament, the resistance can be reduced and the strength can be improved. The finished product has high tensile strength, high electrical conductivity and excellent heat resistance.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it, but the examples given are not intended to limit the present invention.

Example 1

Put the aluminum alloy with a purity of 99.85% into the melting furnace to heat and melt it, keep it warm at 780°C, add _3kg of AlB3 per ton of aluminum water into the melting furnace for boronization, blow into the sodium-removing refining agent (Jinlianxing, GFLUX) with argon gas -J185), refining and standing for 40min to obtain the first liquid aluminum.

Add an intermediate alloy to the first aluminum liquid in the holding furnace, stir for 30 minutes, and obtain the second aluminum liquid; wherein, the temperature of the holding furnace is 800 ° C, and the intermediate alloys are AlSi20, AlFe20, pure Mg ingot, AlY10 and AlZr10, respectively according to 8kg/t, 1.25kg/t, 2.2kg/t, 6kg/t and 50kg/t were added. After the composition of the second aluminum liquid has passed the inspection, a sodium-removing refining agent is blown in, and argon is used for secondary refining. After standing still, the slag is removed, and the third aluminum liquid is obtained after standing; After removing the sodium refining agent, the furnace was stuffed for 20 minutes, the refining temperature was 780°C, and the standing time was 30 minutes. The third aluminum liquid is poured through the holding furnace, and then degassed and filtered through the degassing box and filter box to obtain the fourth aluminum liquid, which is continuously cast at low temperature; the casting temperature is 670 ° C, and the casting The speed is 7.0t/h, the cooling water temperature is 25°C, and the billet discharge temperature is 520°C. Then, the slab obtained by continuous casting is rolled, the rolling temperature is 510° C., and the final rolling temperature is 200° C. to obtain an aluminum rod.

Cool the aluminum rod after winding down to room temperature and then perform two-stage heat treatment, raise the temperature to 590°C for 7 hours, keep it for 15 hours, then cool it down to 440°C, keep it for 40 hours and then quickly cool it down to room temperature to get a super heat-resistant aluminum alloy rod. The obtained aluminum rod is subjected to cold drawing. The amount of deformation is 30% each time, and after 10 times of drawing to 3.2mm, a super heat-resistant aluminum alloy monofilament is obtained. Aging treatment was performed on the obtained super heat-resistant aluminum alloy monofilament, the temperature was raised to 180° C. within 1 hour, and the temperature was kept for 10 hours to obtain a super heat-resistant aluminum alloy wire.

Example 2

Add an intermediate alloy to the first aluminum liquid in the holding furnace, stir for 30 minutes, and obtain the second aluminum liquid; wherein, the temperature of the holding furnace is 780°C, and the intermediate alloys are AlFe20, pure Mg ingot, AlY10 and AlZr10, respectively by 1.25kg /t, 2.2kg/t, 6kg/t and 50kg/t were added. After the composition of the second aluminum liquid has passed the inspection, a sodium-removing refining agent is blown in, and argon is used for secondary refining. After standing still, the slag is removed, and the third aluminum liquid is obtained after standing; After removing the sodium refining agent, the furnace was stuffed for 30 minutes, the refining temperature was 780 ° C, and the standing time was 30 minutes. The third aluminum liquid is poured through the holding furnace, and then degassed and double-stage filtered through the degassing box and filter box to obtain the fourth aluminum liquid, which is continuously cast at low temperature; the casting temperature is 670°C, and the casting The speed is 7.0t/h, the cooling water temperature is 25°C, and the billet discharge temperature is 520°C. Then, the slab obtained by continuous casting is rolled, the rolling temperature is 510° C., and the final rolling temperature is 200° C. to obtain an aluminum rod.

Example 3

Add an intermediate alloy to the first aluminum liquid in the holding furnace, stir for 30 minutes, and obtain the second aluminum liquid; wherein, the temperature of the holding furnace is 800°C, and the intermediate alloys are AlSi20, AlFe20, AlY10 and AlZr10, respectively at 8kg/t, 1.25kg/t, 6kg/t and 50kg/t added. After the composition of the second aluminum liquid has passed the inspection, a sodium-removing refining agent is blown in, and argon is used for secondary refining. After standing still, the slag is removed, and the third aluminum liquid is obtained after standing; After removing the sodium refining agent, the furnace was stuffed for 20 minutes, the refining temperature was 780°C, and the standing time was 30 minutes. The third aluminum liquid is poured through the holding furnace, and then degassed and filtered through the degassing box and filter box to obtain the fourth aluminum liquid, which is continuously cast at low temperature; the casting temperature is 670 ° C, and the casting The speed is 7.0t/h, the cooling water temperature is 25°C, and the billet discharge temperature is 520°C. Then, the slab obtained by continuous casting is rolled, the rolling temperature is 510° C., and the final rolling temperature is 200° C. to obtain an aluminum rod.

Example 4

Add an intermediate alloy to the first aluminum liquid in the holding furnace, stir for 30 minutes, and obtain the second aluminum liquid; wherein, the temperature of the holding furnace is 800°C, and the intermediate alloys are AlSi20, AlFe20, pure Mg ingots and AlZr10, respectively at 8kg/ t, 1.25kg/t, 2.2kg/t and 50kg/t were added. After the composition of the second aluminum liquid has passed the inspection, a sodium-removing refining agent is blown in, and argon is used for secondary refining. After standing still, the slag is removed, and the third aluminum liquid is obtained after standing; After removing the sodium refining agent, the furnace was stuffed for 20 minutes, the refining temperature was 780°C, and the standing time was 30 minutes. The third aluminum liquid is poured through the holding furnace, and then degassed and filtered through the degassing box and filter box to obtain the fourth aluminum liquid, which is continuously cast at low temperature; the casting temperature is 670 ° C, and the casting The speed is 7.0t/h, the cooling water temperature is 25°C, and the billet discharge temperature is 520°C. Then, the slab obtained by continuous casting is rolled, the rolling temperature is 510° C., and the final rolling temperature is 200° C. to obtain an aluminum rod.

Example 5

Add an intermediate alloy to the first aluminum liquid in the holding furnace, stir for 30 minutes, and obtain the second aluminum liquid; wherein, the temperature of the holding furnace is 800°C, and the intermediate alloys are AlSi20, AlFe20, pure Mg ingot and AlY10, respectively, at 8kg/ t, 1.25kg/t, 2.2kg/t and 6kg/t were added. After the composition of the second aluminum liquid has passed the inspection, a sodium-removing refining agent is blown in, and argon is used for secondary refining. After standing still, the slag is removed, and the third aluminum liquid is obtained after standing; After removing the sodium refining agent, the furnace was stuffed for 20 minutes, the refining temperature was 780°C, and the standing time was 30 minutes. The third aluminum liquid is poured through the holding furnace, and then degassed and filtered through the degassing box and filter box to obtain the fourth aluminum liquid, which is continuously cast at low temperature; the casting temperature is 670 ° C, and the casting The speed is 7.0t/h, the cooling water temperature is 25°C, and the billet discharge temperature is 520°C. Then, the slab obtained by continuous casting is rolled, the rolling temperature is 510° C., and the final rolling temperature is 200° C. to obtain an aluminum rod.

Example 6

Add an intermediate alloy to the first aluminum liquid in the holding furnace, stir for 30 minutes, and obtain the second aluminum liquid; wherein, the temperature of the holding furnace is 800°C, and the intermediate alloys are AlFe20, AlY10 and AlZr10, respectively at 1.25kg/t and 6kg /t and 50kg/t added. After the composition of the second aluminum liquid has passed the inspection, a sodium-removing refining agent is blown in, and argon is used for secondary refining. After standing still, the slag is removed, and the third aluminum liquid is obtained after standing; After removing the sodium refining agent, the furnace was stuffed for 20 minutes, the refining temperature was 780°C, and the standing time was 30 minutes. The third aluminum liquid is poured through the holding furnace, and then degassed and filtered through the degassing box and filter box to obtain the fourth aluminum liquid, which is continuously cast at low temperature; the casting temperature is 670 ° C, and the casting The speed is 7.0t/h, the cooling water temperature is 25°C, and the billet discharge temperature is 520°C. Then, the slab obtained by continuous casting is rolled, the rolling temperature is 510° C., and the final rolling temperature is 200° C. to obtain an aluminum rod.

Example 7

Add an intermediate alloy to the first aluminum liquid in the holding furnace, stir for 30 minutes, and obtain the second aluminum liquid; wherein, the temperature of the holding furnace is 800°C, and the intermediate alloy is AlSi20, pure Mg ingot and AlZr10, respectively at 8kg/t, 2.2kg/t and 50kg/t added. After the composition of the second aluminum liquid has passed the inspection, a sodium-removing refining agent is blown in, and argon is used for secondary refining. After standing still, the slag is removed, and the third aluminum liquid is obtained after standing; After removing the sodium refining agent, the furnace was stuffed for 20 minutes, the refining temperature was 780°C, and the standing time was 30 minutes. The third aluminum liquid is poured through the holding furnace, and then degassed and filtered through the degassing box and filter box to obtain the fourth aluminum liquid, which is continuously cast at low temperature; the casting temperature is 670 ° C, and the casting The speed is 7.0t/h, the cooling water temperature is 25°C, and the billet discharge temperature is 520°C. Then, the slab obtained by continuous casting is rolled, the rolling temperature is 510° C., and the final rolling temperature is 200° C. to obtain an aluminum rod.

Example 8

The preparation steps are the same as those in Example 1, except that no aluminum rod is added for high-temperature annealing.

Example 9

The preparation steps are the same as those in Example 1, except that no aluminum rod is added for low-temperature annealing.

Example 10

The preparation steps are the same as in Example 1, except that the monofilament annealing is not added.

Example 11

The preparation steps are the same as those in Example 1, except that the aluminum rod is first annealed at low temperature and then at high temperature.

Effect evaluation 1

The conductivity, tensile strength and heat resistance of Example 1 were tested, and the test results are shown in Table 1.

The conductivity, tensile strength and heat resistance of Examples 2-12 were tested, and the test results are shown in Table 2.

The Zr element can improve the heat resistance of the material very well, but the Zr dissolved in the matrix has a great influence on the resistivity, and the precipitation of Al3Zr after heat treatment can improve the strength while reducing the resistance. Mg and Si elements can The Mg2Si phase is formed to increase the strength of the matrix. At the same time, the Si element can promote the precipitation of the Zr element and reduce the occurrence of segregation. The Fe element can improve the creep resistance of the material. The rare earth element Y can purify the matrix, reduce pores and impurities, and refine the grain , to promote the precipitation of each element. The finished product has high tensile strength, high electrical conductivity, elongation: 5-6%, and excellent heat resistance. After heat resistance test, more than 95% of the tensile strength remains after 240°C heat preservation for 400h, and 96.5-98.3% of the tensile strength remains after 280°C heat preservation for 1h.

Table 1 The properties of the super heat-resistant aluminum alloy wire prepared in Example 1 of the present invention

Table 2 The performance situation of super heat-resistant aluminum alloy wire prepared by comparison of the present invention

Use a sodium-removing refining agent to remove the sodium element in the ingredients. The sodium element is easy to form a eutectic with a low melting point, and it is easy to melt during the high-temperature annealing process to cause structural defects, which will affect the material properties.

Through double-stage annealing and heat treatment at 590-620°C, Si, Mg, and Zr elements can be fully dissolved in the gold matrix, and at the same time, the structure is uniform. After 440-470°C heat treatment, the Zr elements dissolved in the matrix can be completely dissolved. The precipitation is reduced, and the precipitation of Si and Mg elements is prevented by rapid cooling.

Apparently, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation. For those of ordinary skill in the art, on the basis of the above description, other changes or changes in various forms can also be made. It is not necessary and impossible to exhaustively list all the implementation manners here. However, the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims

A super heat-resistant aluminum alloy wire is characterized in that it consists of the following components in weight percentage:

Si: 0.18-0.22%, Mg: 0.21-0.23%, Fe: 0.10-0.15%, Zr: 0.48-0.52%, Y: 0.04-0.08%, and the total amount of Cr, Mn, V and Ti is less than 0.005%. The amount is Al and other unavoidable impurities.
A method for preparing a super heat-resistant aluminum alloy wire according to claim 1, comprising the steps of:

(1) Melting the aluminum alloy, adding AlB 3 for reaction, adding a sodium-removing refining agent, and refining to obtain liquid aluminum A;

(2) adding AlSi20, AlFe20, Mg, AlY10 and AlZr10 to the aluminum liquid A, adding a sodium-removing refining agent, secondary refining, and removing impurities to obtain aluminum liquid B;

(3) Casting, rolling, and double-stage heat treatment are performed on the molten aluminum B to obtain a super heat-resistant aluminum alloy rod;

(4) cold drawing the super heat-resistant aluminum alloy rod, and obtaining the super heat-resistant aluminum alloy wire after aging treatment.
The preparation method according to claim 2, characterized in that, in the step (1), the purity of the aluminum alloy is not less than 99.85%.
The preparation method according to claim 2, characterized in that, in the step (1), the mass ratio of aluminum alloy to AlB3 is 1000:1-5.
The preparation method according to claim 2, characterized in that, in the step (2), AlSi20, AlFe20, Mg, AlY10 and AlZr10 are respectively added 7-9kg, 1-2kg, 2-3kg, 5-7kg and 40-60kg.
The preparation method according to claim 2, characterized in that, in the step (2), the temperature of the secondary refining is 780-800°C, and the time is 20-30min.
The preparation method according to claim 2, characterized in that, in the step (3), the casting temperature is 670-680°C, the casting speed is 7.0-7.5t/h, and the billet discharge temperature is 520-550°C.
The preparation method according to claim 2, characterized in that, in the step (3), during the rolling process, the rolling temperature is 510-540°C, and the finishing rolling temperature is 200-300°C.
The preparation method according to claim 2, characterized in that, the specific operation of the two-stage heat treatment is: cooling the cast and rolled aluminum liquid B to room temperature, raising the temperature to 590-620°C for 7-8 hours, and keeping it warm for 15 -20h; cool down to 440-470°C, keep warm for 40-60h, and cool down to room temperature at a cooling rate of 9-11°C/s.
The preparation method according to claim 2, characterized in that, the aging treatment is to raise the temperature to 180-200° C. for 1-2 hours, and keep the temperature for 10-30 hours.