Method for preparing high-strength high-conductivity heat-resistant aluminum alloy conductor in short process

Abstract

The invention discloses a method for preparing a high-strength, high-conductivity and heat-resistant aluminum alloy conductor in a short process, belongs to the field of aluminum alloy conductors, and comprises the following steps: S1, preparing the high-strength, high-conductivity and heat-resistant aluminum alloy conductor in the short process; alloy smelting and component design are conducted, specifically, an aluminum alloy melt is prepared, and the aluminum alloy melt is prepared from, by mass, 0.05%-0.15% of Zr, 0.10%-0.25% of Fe, smaller than or equal to 0.10% of Si, 0.005%-0.02% of B and the balance Al and inevitable impurities; wherein the mass ratio of iron to silicon, namely Fe / Si, is controlled to be 1.5-3.0. According to the method, a plurality of traditional independent long-flow procedures including casting, homogenization, hot rolling and the like are creatively integrated into a core procedure of continuous rheological extrusion, and one-step forming from liquid metal to a rod blank is achieved. And homogenization heat treatment and intermediate annealing are omitted, the production period is greatly shortened, energy consumption and equipment investment are reduced, and the production efficiency can be improved by more than 30%.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aluminum alloy conductor, in particular, relates to a short process for preparing high-strength high-conductivity heat-resistant aluminum alloy conductor. BACKGROUND

[0002] With the development of extra-high voltage power transmission, long-distance large-capacity power transmission and urban power grid capacity expansion and reconstruction, higher requirements are put forward for the performance of overhead conductors. Although the traditional pure aluminum conductor has high conductivity, it has low strength and poor heat resistance, which is difficult to meet the application in complex environments such as large span and heavy ice area. High-strength high-conductivity heat-resistant aluminum alloy conductor has become an ideal choice to replace traditional conductor due to its excellent comprehensive performance.

[0003] At present, the mainstream process for preparing high-strength high-conductivity heat-resistant aluminum alloy conductor generally includes: semi-continuous casting to prepare large-size round ingot → homogenization heat treatment → sawing → milling → heating → hot rolling into rod → multi-pass cold drawing → intermediate annealing → final drawing into target line diameter → aging heat treatment. The traditional process has long process flow, high energy consumption and large equipment investment, and multiple heating and cold working easily lead to coarse grains and increase of internal defects, affecting the conductivity and fatigue performance of the final product. Especially the homogenization heat treatment and intermediate annealing links, which take several hours to several tens of hours, seriously restrict the production efficiency and cost control.

[0004] Therefore, it is of important industrial application value to develop an aluminum alloy conductor preparation method with short process flow, low energy consumption, high efficiency, and excellent strength, conductivity and heat resistance of the product. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a short process for preparing high-strength high-conductivity heat-resistant aluminum alloy conductor, which solves the problems raised in the background art. To achieve the above purpose, the present application is realized by the following technical scheme: A short process for preparing high-strength high-conductivity heat-resistant aluminum alloy conductor, comprising the following steps: S1. Alloy smelting and composition design: preparing an aluminum alloy melt, the composition of which is as follows in terms of mass percentage: Zr: 0.05%-0.15%, Fe: 0.10%-0.25%, Si: ≤0.10%, B: 0.005%-0.02%, the balance being Al and unavoidable impurities; wherein the mass ratio of iron to silicon Fe / Si is controlled between 1.5-3.0; S2. Melt treatment: refining and purifying the melt in S1, and then standing and heat preservation; S3. Continuous rheological extrusion forming: introducing the melt treated in S2 into a continuous rheological extruder, and directly extruding and forming into an aluminum alloy rod blank with a set size; S4. Online solution and rapid cooling: immediately perform online solution treatment on the just-extruded rod blank in S3, and then perform forced rapid cooling; S5. Continuous cold drawing: continuously perform multi-pass cold drawing on the rod blank treated in S4 to process into a target-diameter wire; S6. Aging heat treatment: perform graded aging heat treatment on the wire obtained in S5.

[0006] Preferably, in S1, the content of each of the inevitable impurities is ≤0.03%, and the total content of the impurities is ≤0.10%.

[0007] Preferably, in S2, the refining is performed by argon rotary blowing or hexachloroethane tablet, and the purification treatment is performed by foam ceramic filter plate filtering.

[0008] Preferably, in S3, the temperature of the melt introduced into the continuous rheological extruder is controlled to be 10-30℃ above the liquidus temperature; and the temperature of the rod blank extruded from the die of the extruder is 450-550℃.

[0009] Preferably, in S3, the continuous rheological extruder is a Conform continuous extruder, and the diameter of the rod blank ranges from 8.0 mm to 12.0 mm.

[0010] Preferably, in S4, the online solution treatment is realized by an induction heating device or an electric resistance heating tunnel, the solution treatment temperature is 480-520℃, and the holding time is 10-60 seconds.

[0011] Preferably, in S4, the forced rapid cooling is performed by water mist cooling or high-pressure gas cooling, the cooling rate is not less than 50℃ / second, and the final cooling temperature is not higher than 100℃.

[0012] Preferably, in S5, the total deformation amount of the cold drawing is 75%-90%; the die angle of the drawing die used in the cold drawing process is 12°-16°, and the ratio of the length of the sizing belt to the wire diameter is 0.8-1.2.

[0013] Preferably, in S6, the graded aging heat treatment specifically includes: K1, first-stage preheating: holding at 100-130℃ for 1-3 hours; K2, second-stage aging: heating to 170-230℃ and holding for 2-8 hours; K3, cooling: after the holding, air cooling to room temperature.

[0014] The application has the following advantages: (1) The process of the application is very short and energy efficient: the application innovatively integrates multiple independent long process procedures such as "casting → homogenization → hot rolling" into a core process of "continuous flow extrusion", realizing "one-step" forming from liquid metal to rod blank. The homogenization heat treatment and intermediate annealing are omitted, the production cycle is greatly shortened, the energy consumption and equipment investment are reduced, and the production efficiency can be increased by more than 30%.

[0015] (2) The application significantly refines the grains through severe shear deformation and rapid solidification, eliminates the macrosegregation, shrinkage and other defects commonly found in traditional casting, and obtains a rod blank with uniform composition and dense structure. Online solid solution and rapid cooling: making full use of the extrusion residual heat for online solid solution, avoiding secondary heating, and achieving significant energy saving effect. Rapid cooling effectively inhibits the coarsening of the second phase (such as Al3Fe), and maximizes the supersaturated solid solubility of Zr element, laying a foundation for subsequent aging precipitation strengthening. Synergistic effect: fine and uniform initial structure, high supersaturated solid solution and high density of dislocation cold deformation structure, and grading aging process synergistic effect, promote the uniform and dispersed precipitation of Al3Zr and other nano-strengthening phases, thereby simultaneously greatly improving the strength, electrical conductivity and heat resistance of the wire.

[0016] (3) The application precisely controls the content of Zr and Fe and the Fe / Si ratio, uses Zr to form heat-resistant Al3Zr phase to increase the recrystallization temperature, and uses Fe to form fine AlFe phase to play a certain strengthening role without significantly damaging the electrical conductivity. The addition of trace B can refine the Al3Zr phase and further improve the precipitation strengthening effect. DETAILED DESCRIPTION

[0017] In order for those skilled in the art to better understand the scheme of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0018] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below in combination with the embodiments.

[0019] Embodiment one The embodiment provides a method for preparing a high-strength high-conductivity heat-resistant aluminum alloy wire through a short process, comprising the following steps: S1, alloy smelting and composition design: an aluminum alloy melt is prepared, which has a composition by mass percentage of Zr: 0.05%, Fe: 0.10%, Si: ≤0.10%, B: 0.005%, and the balance of Al and inevitable impurities; wherein the mass ratio of iron to silicon Fe / Si is controlled between 1.5-3.0; Among the inevitable impurities, the content of a single impurity is ≤0.03%, and the total content of impurities is ≤0.10%.

[0020] S2, melt treatment: the melt in S1 is subjected to refining and purification treatment, and then is placed and kept warm; The refining is performed by argon rotary blowing or hexachloroethane tablet, and the purification treatment is performed by a foam ceramic filter plate.

[0021] S3, continuous rheological extrusion forming: the melt treated in S2 is introduced into a continuous rheological extruder, and is directly extruded into an aluminum alloy rod blank of a set size; The temperature of the melt introduced into the continuous rheological extruder is controlled at 10℃ above the liquidus temperature; and the temperature of the rod blank extruded from the die of the extruder is 450℃; The continuous rheological extruder is a Conform continuous extruder, and the diameter of the rod blank ranges from 8.0mm.

[0022] S4, online solid solution and rapid cooling: the rod blank just extruded in S3 is immediately subjected to online solid solution treatment, and then is subjected to forced rapid cooling; The online solid solution treatment is realized by an induction heating device or an electric resistance heating tunnel, the solid solution treatment temperature is 480℃, and the holding time is 10 seconds; The forced rapid cooling is performed by water mist cooling or high-pressure gas cooling, the cooling rate is not less than 50℃ / s, and the final cooling temperature is not higher than 100℃.

[0023] S5, continuous cold drawing: the rod blank treated in S4 is subjected to continuous multi-pass cold drawing to process a target diameter wire; The total deformation amount of the cold drawing is 75%; the die angle of the drawing die used in the cold drawing process is 12°, and the ratio of the length of the sizing belt to the wire diameter is 0.8.

[0024] S6, aging heat treatment: the wire obtained in S5 is subjected to graded aging heat treatment.

[0025] The graded aging heat treatment specifically includes: K1, first stage preheating: holding at 100℃ for 1 hour; K2, second stage aging: heating to 170℃ and holding for 2 hours; K3, cooling: after the holding is completed, air cooling to room temperature.

[0026] Example Two A method for preparing high-strength and high-conductivity heat-resistant aluminum alloy wire in a short process, comprising the following steps: S1. Alloy smelting and composition design: preparing an aluminum alloy melt, the composition of which is as follows in terms of mass percentage: Zr: 0.15%, Fe: 0.25%, Si: ≤0.10%, B: 0.02%, the balance being Al and unavoidable impurities; wherein the mass ratio of iron to silicon Fe / Si is controlled to be between 1.5-3.0; In the unavoidable impurities, the content of each single impurity is ≤0.03%, and the total content of impurities is ≤0.10%.

[0027] S2. Melt treatment: refining and purifying the melt in S1, and then standing and heat preservation; The refining is performed by argon rotary blowing or hexachloroethane tablets, and the purifying treatment is performed by a foam ceramic filter plate.

[0028] S3. Continuous rheological extrusion forming: introducing the melt treated in S2 into a continuous rheological extruder to directly extrude and form an aluminum alloy rod blank of a set size; The temperature of the melt introduced into the continuous rheological extruder is controlled to be 30℃ above the liquidus temperature; and the temperature of the rod blank extruded from the die of the extruder is 550℃; The continuous rheological extruder is a Conform continuous extruder, and the diameter of the rod blank ranges from 12.0 mm.

[0029] S4. Online solid solution and rapid cooling: immediately performing online solid solution treatment on the rod blank just extruded in S3, and then performing forced rapid cooling; The online solid solution treatment is realized by an induction heating device or an electric resistance heating tunnel, the solid solution treatment temperature is 520℃, and the heat preservation time is 60 seconds; The forced rapid cooling is performed by water mist cooling or high-pressure gas cooling, the cooling rate is not less than 50℃ / s, and the final cooling temperature is not higher than 100℃.

[0030] S5. Continuous cold drawing: continuously and multi-pass cold drawing the rod blank treated in S4 to a target diameter wire; The total deformation amount of the cold drawing is 90%; the die angle of the drawing die used in the cold drawing process is 16°, and the ratio of the length of the sizing belt to the wire diameter is 1.2.

[0031] S6. Aging heat treatment: performing graded aging heat treatment on the wire obtained in S5.

[0032] The graded aging heat treatment specifically includes: K1, first stage preheating: heat preservation at 130℃ for 3 hours; K2, second stage aging: heating to 230 °C and holding for 8 hours; K3, cooling: after holding, air cooling to room temperature.

[0033] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical solutions and the inventive concept of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for preparing high-strength, high-conductivity, and heat-resistant aluminum alloy wires using a short-process method, characterized in that, Includes the following steps: S1; Alloy smelting and composition design: Prepare aluminum alloy melt with the following composition by mass percentage: Zr: 0.05%-0.15%, Fe: 0.10%-0.25%, Si: ≤0.10%, B: 0.005%-0.02%, with the balance being Al and unavoidable impurities; wherein the mass ratio of iron to silicon, Fe / Si, is controlled between 1.5 and 3.0; S2. Melt treatment: The melt in S1 is refined and purified, and then kept at a constant temperature. S3. Continuous rheological extrusion forming: The melt treated by S2 is introduced into a continuous rheological extruder and directly extruded into an aluminum alloy rod blank of a set size; S4. Online solution treatment and rapid cooling: The bar billet that has just been extruded in S3 is immediately subjected to online solution treatment, followed by forced rapid cooling; S5. Continuous cold drawing: The rod blank treated by S4 is continuously cold drawn in multiple passes to process the wire to the target diameter; S6. Aging heat treatment: The conductor obtained in S5 is subjected to graded aging heat treatment.

2. The method for preparing high-strength, high-conductivity, and heat-resistant aluminum alloy wires via a short process according to claim 1, characterized in that, In S1, among the unavoidable impurities, the content of a single impurity is ≤0.03%, and the total content of impurities is ≤0.10%.

3. The method for preparing high-strength, high-conductivity, and heat-resistant aluminum alloy wires via a short process according to claim 2, characterized in that, In S2, the refining is carried out by argon rotary jetting or hexachloroethane tablets, and the purification process is carried out by filtration using foam ceramic filter plates.

4. The method for preparing high-strength, high-conductivity, and heat-resistant aluminum alloy wires via a short process according to claim 3, characterized in that, In S3, the temperature of the melt introduced into the continuous rheological extruder is controlled at 10-30°C above the liquidus temperature; the temperature of the billet extruded from the extruder die is 450-550°C.

5. The method for preparing high-strength, high-conductivity, and heat-resistant aluminum alloy wires via a short process according to claim 4, characterized in that, In S3, the continuous rheological extruder is a Conform continuous extruder, and the diameter of the bar billet ranges from 8.0 to 12.0 mm.

6. The method for preparing high-strength, high-conductivity, and heat-resistant aluminum alloy wires via a short process according to claim 5, characterized in that, In S4, the online solution treatment is achieved through an induction heating device or a resistance heating tunnel, with a solution treatment temperature of 480-520℃ and a holding time of 10-60 seconds.

7. The method for preparing high-strength, high-conductivity, and heat-resistant aluminum alloy wires via a short process according to claim 6, characterized in that, In S4, the forced rapid cooling adopts water mist cooling or high-pressure air cooling, with a cooling rate of not less than 50°C / second and a final cooling temperature of not more than 100°C.

8. The method for preparing high-strength, high-conductivity, and heat-resistant aluminum alloy wires using a short-process method according to claim 7, characterized in that, In S5, the total deformation of the cold drawing is 75%-90%; the die angle of the drawing die used in the cold drawing process is 12°-16°, and the ratio of the sizing strip length to the wire diameter is 0.8-1.

2.

9. The method for preparing high-strength, high-conductivity, and heat-resistant aluminum alloy wires using a short-process method according to claim 8, characterized in that, In S6, the graded aging heat treatment specifically includes: K1, First stage preheating: Keep warm at 100-130℃ for 1-3 hours; K2, second stage aging: heat to 170-230℃ and hold for 2-8 hours; K3, Cooling: After the heat preservation is completed, remove from the furnace and air cool to room temperature.