阅读说明：本技术 一种耐热性好的高导电率软铝单丝及其制备方法 (High-conductivity soft aluminum monofilament with good heat resistance and preparation method thereof ) 是由 陈保安 祝志祥 潘学东 张强 陈新 杨长龙 丁一 赵丽丽 张宏宇 韩钰 韦瑾 于 2019-10-30 设计创作，主要内容包括：本发明提出了一种耐热性好的高导电率软铝单丝及其制备方法,该软铝单丝以纯度≥99.7％的工业纯铝,Al-B中间合金和Al-RE中间合金为原料制得,其包括按质量百分比计的下述组分：B≤0.02％,RE：0.1-0.3％,Si:≤0.07％,Fe:≤0.2％,(V+Ti+Cr+Mn)≤0.012％,其余为Al和不可避免的杂质；RE为La或Ce中的一种或两种,本发明在提高软铝单丝导电率的基础上还大大提高了其耐热性,使软铝单丝更加满足电网建设的需要。(The invention provides a high-conductivity soft aluminum monofilament with good heat resistance and a preparation method thereof, the soft aluminum monofilament is prepared by taking industrial pure aluminum with the purity of more than or equal to 99.7%, Al-B intermediate alloy and Al-RE intermediate alloy as raw materials, and comprises the following components in percentage by mass: b is less than or equal to 0.02%, RE: 0.1 to 0.3 percent of Si, less than or equal to 0.07 percent of Fe, less than or equal to 0.2 percent of (V + Ti + Cr + Mn), less than or equal to 0.012 percent of (V + Ti + Cr + Mn), and the balance of Al and inevitable impurities; RE is one or two of La or Ce, and the heat resistance of the soft aluminum monofilament is greatly improved on the basis of improving the conductivity of the soft aluminum monofilament, so that the soft aluminum monofilament can better meet the requirements of power grid construction.)

1. The high-conductivity soft aluminum monofilament with good heat resistance is characterized in that the monofilament is prepared from industrial pure aluminum with the purity of more than or equal to 99.7%, Al-B intermediate alloy and Al-RE intermediate alloy as raw materials, and comprises the following components in percentage by mass: b is less than or equal to 0.02%, RE: 0.1 to 0.3 percent of Si, less than or equal to 0.07 percent of Fe, less than or equal to 0.2 percent of (V + Ti + Cr + Mn), less than or equal to 0.012 percent of (V + Ti + Cr + Mn), and the balance of Al and inevitable impurities;

and the RE is one or two of La or Ce.

2. A soft aluminum monofilament as claimed in claim 1, wherein said soft aluminum monofilament comprises: 0.02 percent of B, 0.3 percent of RE, less than or equal to 0.04 percent of Si, less than or equal to 0.18 percent of Fe, (V + Ti + Cr + Mn) less than or equal to 0.012 percent, and the balance of aluminum and inevitable impurities.

3. A soft aluminum monofilament as claimed in claim 1, wherein said soft aluminum monofilament comprises: 0.01-0.015% of B, 0.15-0.3% of RE, 0.05% of Si, 0.15% of Fe, (V + Ti + Cr + Mn) is 0.012%, and the balance of aluminum and inevitable impurities.

4. A soft aluminum monofilament as claimed in claim 1, wherein said soft aluminum monofilament comprises: 0.012% of B, 0.2% of RE, 0.07% of Si, 0.14% of Fe, (V + Ti + Cr + Mn) ═ 0.008%, and the balance of aluminum and inevitable impurities.

5. A method of producing a soft aluminium monofilament according to claims 1 to 4, characterized in that it comprises the steps of:

(1) smelting;

(2) refining;

(3) casting;

(4) and (6) rolling.

6. The method for preparing soft aluminum monofilament as claimed in claim 5, wherein the step 1) comprises melting the raw material at 730-780 ℃ and standing for 15-30 min.

7. The method for preparing soft aluminum monofilament as claimed in claim 5, wherein the aluminum ingot and Al-B intermediate alloy are melted at 750-780 ℃, and then the Al-RE intermediate alloy is added at 730-750 ℃ for melting and then is left standing for 20-30 min.

8. A method for preparing a soft aluminum monofilament as claimed in claim 5, wherein the step 2) comprises: blowing 0.1 to 0.2 percent of refining agent or 0.3 to 0.5 percent of C into the molten liquid obtained in the step 1) with the temperature reduced to 710-730 DEG C₂Cl₆Standing for 20-30min, and removing slag.

9. A method for preparing a soft aluminum monofilament as claimed in claim 5, wherein the step 3) comprises: the aluminum alloy liquid is poured into the die at the temperature of 690 and 710 ℃.

10. The method for preparing the soft aluminum monofilament as claimed in claim 5, wherein the soft aluminum monofilament is obtained by heat preservation at 280-320 ℃ for 4-10h after the rolling in the step 4).

11. The method for preparing soft aluminum monofilament as claimed in claim 10, wherein the round aluminum alloy rod with a diameter of 9.5mm is obtained by 5 passes of rolling at 520-530 ℃, and then the monofilament with a diameter of 3-4mm is obtained by 8-12 passes of drawing.

Technical Field

The invention relates to a preparation method of an electrical conductor material, in particular to a high-conductivity soft aluminum monofilament with good heat resistance and a preparation method thereof.

Background

The characteristics of energy centralized distribution and economic development determine that large-capacity, low-loss and long-distance power transmission must be carried out. The rapid development of power grid construction also puts higher requirements on the performance of overhead conductors. The steel-cored aluminum strand of one of the most applied conductors in the overhead transmission line accounts for more than 80% of the whole conductor type, so that the optimization of the performance of the steel-cored aluminum strand is required by the development of electric energy and has great economic benefit.

Chinese patent CN201610388851 discloses a low-cost 63% IACS high-conductivity duralumin conductor and its manufacturing method, however, its heat resistance still cannot meet the requirement of power grid construction development.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the high-conductivity soft aluminum monofilament with good heat resistance.

The technical scheme provided by the invention is as follows:

the high-conductivity soft aluminum monofilament with good heat resistance is prepared from industrial pure aluminum with the purity of more than or equal to 99.7%, Al-B intermediate alloy and Al-RE intermediate alloy as raw materials, and comprises the following components in percentage by mass: b is less than or equal to 0.02%, RE: 0.1 to 0.3 percent of Si, less than or equal to 0.07 percent of Fe, less than or equal to 0.2 percent of (V + Ti + Cr + Mn), less than or equal to 0.012 percent of (V + Ti + Cr + Mn), and the balance of Al and inevitable impurities;

and the RE is one or two of La or Ce.

Further, the soft aluminum monofilament comprises: 0.02 percent of B, 0.3 percent of RE, less than or equal to 0.04 percent of Si, less than or equal to 0.18 percent of Fe, (V + Ti + Cr + Mn) less than or equal to 0.012 percent, and the balance of aluminum and inevitable impurities.

Further, the soft aluminum monofilament comprises: 0.01-0.015% of B, 0.15-0.3% of RE, 0.05% of Si, 0.15% of Fe, (V + Ti + Cr + Mn) is 0.012%, and the balance of aluminum and inevitable impurities.

Further, the soft aluminum monofilament comprises: 0.012% of B, 0.2% of RE, 0.07% of Si, 0.14% of Fe, (V + Ti + Cr + Mn) ═ 0.008%, and the balance of aluminum and inevitable impurities.

The preparation method of the soft aluminum monofilament comprises the following steps:

(1) smelting;

(2) refining;

(3) casting;

(4) and (6) rolling.

Further, the step 1) comprises the steps of melting the raw materials at 730-780 ℃ and standing for 15-30 min.

Further, the aluminum ingot and the Al-B intermediate alloy are smelted at 750-780 ℃, and then the Al-RE intermediate alloy is added at 730-750 ℃ for smelting and then standing for 20-30 min.

Further, the step 2) comprises: blowing 0.1 to 0.2 percent of refining agent or 0.3 to 0.5 percent of C into the molten liquid obtained in the step 1) with the temperature reduced to 710-730 DEG C₂Cl₆Standing for 20-30min, and removing slag.

Further, the step 3) comprises: the aluminum alloy liquid is poured into the die at the temperature of 690 and 710 ℃.

Further, after the rolling in the step 4), the soft aluminum monofilament is obtained by heat preservation for 4-10h at the temperature of 280-320 ℃.

Further, rolling the round aluminum alloy rod with the diameter of 9.5mm at the temperature of 520 ℃ and 530 ℃ for 5 times, and drawing the round aluminum alloy rod with the diameter of 3 mm to 4mm for 8 to 12 times.

Compared with the closest prior art, the technical scheme provided by the invention has the following beneficial effects:

(1) the technical scheme provided by the invention develops the soft aluminum monofilament with excellent heat resistance and electric conductivity by using industrial pure aluminum with the purity of more than or equal to 99.7%, Al-B intermediate alloy and Al-RE intermediate alloy as raw materials, the strength residual rate of the soft aluminum monofilament can reach 93% when the soft aluminum monofilament is kept at 230 ℃ for 1h, the electric conductivity of the soft aluminum monofilament can reach 63.5% (20 ℃) IACS, and the soft aluminum monofilament can meet the requirement of power grid construction.

(2) The soft aluminum monofilament provided by the invention has excellent mechanical properties, the tensile strength of 60-80MPa and the elongation of 20-30%, and is suitable for large-scale application of power transmission lines.

Detailed Description

The technical solutions provided by the present invention are described below clearly and completely, and it is obvious that the described embodiments are only a part of the present invention, and not all of it.

The invention aims to develop an Al-RE-B soft aluminum monofilament by using an electrical aluminum ingot with the purity of 99.7 percent as a raw material, and solve the technical problem of poor heat resistance of the high-conductivity soft aluminum monofilament.

The action and mechanism of each alloy element are as follows:

b: if the impurity elements exist in a solid solution state, the influence on the conductivity is very large, and the invention provides an effective method for reducing the impurity content, namely boronization treatment, namely, Al-B intermediate alloy is added into the aluminum alloy, and B can react with transition group impurity elements such as Cr, Mn, V, Ti and the like, so that the impurity elements are converted into a compound state from the solid solution state and are deposited at the bottom of a melt, and the conductivity of the aluminum alloy is improved.

RE: the La or Ce introduced in the invention has the function of purifying the alloy liquid, can change impurity elements from solid solution atoms into a second phase, and can obviously improve the comprehensive performance of the aluminum alloy.

Si: silicon is one of impurity elements in industrial aluminum, and Si can react with elements such as Fe, Re and the like to generate a second phase, so that the mechanical property of the aluminum alloy is improved.

Fe: iron is a major impurity in industrial aluminum. Iron usually appears as coarse primary crystals or as aluminum-iron-silicon compounds, which increase the hardness of aluminum to some extent but reduce the plasticity of aluminum, so care should be taken to control the iron content.

V, Mn, Cr, Ti: when impurity elements such as Ti, V, Mn, and Cr in the aluminum conductor exist in a solid solution state, free electrons in the conductor material are easily absorbed and the incomplete electron layer is filled. The reduction of the number of conduction electrons leads to the reduction of the conductivity of the aluminum conductor, so that the strict control of the contents of the elements has important practical significance for ensuring the quality of the aluminum conductor.

The preparation process of the high-conductivity soft aluminum monofilament with good heat resistance comprises the following steps:

(1) smelting: adding an industrial pure aluminum ingot with the purity of more than or equal to 99.7% into a smelting furnace at the temperature of 750-780 ℃, and adding an Al-B intermediate alloy for boronizing after pure aluminum is completely melted; and cooling to 730-750 ℃, adding the Al-RE intermediate alloy, melting, stirring for 10-15 min, and standing for 20-30 min.

(2) Refining: cooling to 710-730 ℃, blowing 0.1-0.2% of refining agent by using N2, or adding 0.3-0.5% of C₂Cl₆Standing for 20-30min, and removing slag.

(3) Casting: and cooling to 690-710 ℃ and pouring the aluminum alloy liquid into the die.

(4) Rolling: rolling the aluminum alloy round bar into an aluminum alloy round bar with the diameter of 9.5mm by 5 passes at the rolling temperature of 520-530 ℃;

drawing an aluminum alloy round rod with the diameter of 9.5mm for 8-12 times to obtain a monofilament with the diameter of 3-4mm, and preserving heat for 4-10 hours at 280-320 ℃ to obtain the high-heat-resistance Al-RE-B soft aluminum monofilament.

And (3) the steps (3) to (4) can also adopt a continuous casting and rolling method to obtain the aluminum alloy round rod with the diameter of 9.5 mm.