Rare earth element composite modified aluminum alloy single wire material and preparation method thereof

Abstract

The invention provides a rare earth element composite modified aluminum alloy single wire material and a preparation method thereof, and the aluminum alloy single wire material comprises the following element components in percentage by mass: 0.65%-0.95% of magnesium, 0.50%-0.80% of silicon, 0.10%-0.50% of gadolinium, 0.10%-0.50% of ytterbium and the balance of aluminum and inevitable impurity elements. The preparation method comprises the stages of smelting treatment, continuous casting and rolling, solid solution aging, drawing forming and low-temperature aging. In the smelting treatment stage, element components of aluminum, magnesium and silicon in the aluminum alloy single wire are added in the form of elementary substances, and element components of gadolinium and ytterbium are added in the form of intermediate alloy. The rare earth elements gadolinium and ytterbium of the same family are compositely doped on the basis of aluminum-magnesium-silicon alloy components, and the gadolinium and ytterbium generate a synergistic effect, so that the mechanical property of the aluminum alloy single wire material can be improved, the total amount of the doped rare earth elements is reduced, and the influence on the conductivity of the aluminum alloy single wire material is further reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of overhead power transmission conductor, and particularly relates to a rare earth element composite modified aluminum alloy single wire material and a preparation method thereof. BACKGROUND

[0002] Overhead power transmission line is an important physical carrier for realizing cross-regional energy allocation and power supply. As an important component of overhead power transmission line, conductor shoulders the key task of conducting current and transmitting electric energy, and bears normal operation load and additional load caused by environmental factors such as strong wind and icing, so the overhead power transmission conductor material should have good electrical conductivity and bearing capacity. Steel-cored aluminum stranded wire is a main type of conductor due to its simple structure, convenient erection and maintenance, and low cost.

[0003] However, with the rapid expansion of the spatial scale of the power grid, more stringent requirements are put forward for the loss level of overhead power transmission line. The large power loss and low tensile strength of traditional steel-cored aluminum stranded wire become an important bottleneck for line capacity reduction and loss reduction, which limits its large-scale application.

[0004] The existing aluminum-magnesium-silicon alloy has the characteristics of low density, good electrical conductivity and thermal conductivity, and excellent corrosion resistance, and is an ideal overhead power transmission conductor material system. However, the aluminum alloy overhead power transmission conductor made of aluminum-magnesium-silicon alloy is prone to strand breakage due to its limited mechanical tensile strength, which greatly limits the application of aluminum alloy conductor in overhead power transmission line, especially in heavy icing and large span power transmission line.

[0005] Correspondingly, there is a need for a new aluminum alloy single wire material and a preparation method thereof to solve the above problems. SUMMARY

[0006] The purpose of the present application is to solve the problem of poor tensile strength of the existing aluminum alloy single wire material.

[0007] The purpose of the present application is achieved by adopting the following technical solutions:

[0008] The present application provides a rare earth element composite modified aluminum alloy single wire material, the element components of the aluminum alloy single wire material include, by mass percentage: magnesium 0.65%-0.95%, silicon 0.50%-0.80%, gadolinium 0.10%-0.50%, ytterbium 0.10%-0.50%, and the balance is aluminum and unavoidable impurity elements.

[0009] Preferably, the magnesium content is 0.75%-0.90%; and / or the silicon content is 0.50%-0.65%; and / or the gadolinium content is 0.10%-0.30%; and / or the ytterbium content is 0.10%-0.30%.

[0010] Based on the same inventive concept, the application further provides a preparation method of the rare earth element composite modified aluminum alloy single wire material, which comprises a melting treatment, continuous casting and rolling, solid solution aging, drawing forming and low-temperature aging stages; in the melting treatment stage, the element components aluminum, magnesium and silicon in the aluminum alloy single wire are added in the form of elemental substance, and the element components gadolinium and ytterbium are added in the form of intermediate alloy.

[0011] Preferably, in the melting treatment stage, the ingredient aluminum, magnesium and silicon blocks of elemental substance, gadolinium intermediate alloy and ytterbium intermediate alloy are obtained according to the element component proportion of the aluminum alloy single wire material; all the ingredients are melted at 750-770°C, and the alloy melt is obtained after stirring and filtering under argon atmosphere; the alloy melt is kept and placed at 720-760°C, and the keeping and placing time is 0.5-1h.

[0012] Preferably, in the continuous casting and rolling stage, the alloy melt after keeping and placing is cast into a crystallizer to obtain a casting blank, the casting speed is 12-15m / min, and the casting blank temperature after leaving the crystallizer is 460-480°C; the casting blank is subjected to continuous casting and rolling to obtain an aluminum alloy round rod with a diameter of 9.5mm, and the open rolling temperature of the casting blank is 510-530°C.

[0013] Preferably, in the solid solution aging stage, the aluminum alloy round rod is sequentially subjected to solid solution quenching and aging treatment; the solid solution temperature of the solid solution quenching is 530-560°C, the solid solution keeping and placing time is 0.5-3h, and then quenching, the interval time before quenching is ≤10s, and the cooling medium temperature used for quenching is ≤40°C; the aging temperature of the aging treatment is 120-180°C, and the aging keeping and placing time is 5-15h.

[0014] Preferably, in the drawing forming stage, the aluminum alloy round rod is drawn for nine times, and the diameter is reduced from 9.5mm to 3.44mm to form an alloy wire, the radial deformation amount of each time is ≤12%, the drawing speed is 3-8m / s, and the drawing temperature is 35-60°C.

[0015] Preferably, in the drawing forming stage, nine drawing die sets are used, and the hole diameters of the drawing die sets change in turn as follows: 8.42mm→7.50mm→6.68mm→5.95mm→5.30mm→4.72mm→4.21mm→3.75mm→3.44mm, and the relative sliding rates of each time are in turn 1.01→1.01→1.01→1.015→1.02→1.02→1.03→1.03→1.04.

[0016] Preferably, in the low-temperature aging stage, the aging temperature of the alloy wire is 110-140°C, the aging keeping and placing time is 6-12h, and then the alloy wire is cooled to room temperature.

[0017] Preferably, the gadolinium intermediate alloy is Mg-30% Gd alloy, and the ytterbium intermediate alloy is Al-10% Yb alloy.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] The present application provides a rare earth element composite modified aluminum alloy single wire material, and the material components of the aluminum alloy single wire include, in percentage by mass: 0.65%-0.95% of magnesium, 0.50%-0.80% of silicon, 0.10%-0.50% of gadolinium, 0.10%-0.50% of ytterbium, and the balance of aluminum and inevitable impurity elements. By compounding and doping the same group rare earth elements gadolinium and ytterbium on the basis of aluminum-magnesium-silicon alloy components, through the synergistic effect between the rare earth elements, the mechanical properties of the aluminum alloy single wire material can be improved, and the total amount of doped rare earth elements can be reduced, thereby reducing the influence on the electrical conductivity of the aluminum alloy single wire material. Compared with the aluminum alloy single wire before modification, the rare earth element composite modified aluminum alloy single wire material provided by the present application has higher electrical conductivity and tensile strength, and can meet the requirements of low loss and high reliability of overhead transmission lines.

[0020] The preparation method of the rare earth element composite modified aluminum alloy single wire material provided by the present application includes melting treatment, continuous casting and rolling, solid solution aging, drawing forming, and low-temperature aging stages. In the melting treatment stage, the aluminum, magnesium, and silicon elements in the aluminum alloy single wire are added in the form of single elements, and the gadolinium and ytterbium elements are added in the form of intermediate alloys, which can reduce the loss of rare earth elements in the preparation process. Among them, the aluminum alloy round rod is subjected to solid solution aging treatment and the aluminum alloy single wire is subjected to low-temperature aging treatment, which can eliminate the primary Mg-Si transition phase β', and promote the precipitation of the Mg-Si transition phase β". At the same time, by using the effects of deformation strengthening and dislocation recovery, the electrical conductivity and mechanical properties of the aluminum alloy single wire material can be balanced. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The TEM bright field image of the microstructure of the rare earth element composite modified aluminum alloy single wire material of the present application. DETAILED DESCRIPTION

[0022] The following examples are provided to better further understand the present application, and do not limit the best embodiments, and do not limit the content and protection scope of the present application. Any person who obtains any product same or similar to the present application under the inspiration of the present application or by combining the present application with other prior art features falls within the protection scope of the present application.

[0023] In the present application, the specific experimental stages or conditions are not specified, and can be performed according to the conventional experimental stage operations or conditions described in the literature in the art.

[0024] The application provides a rare earth element composite modified aluminum alloy single wire material, and element components of the aluminum alloy single wire material include, in percentage by mass: 0.65-0.95% of magnesium, 0.50-0.80% of silicon, 0.10-0.50% of gadolinium, 0.10-0.50% of ytterbium, and the balance of aluminum and inevitable impurity elements.

[0025] The preparation method of the rare earth element composite modified aluminum alloy single wire material includes 1) a smelting treatment, 2) a continuous casting and rolling, 3) a solid solution aging, 4) a drawing forming, and 5) a low-temperature aging stage; in the smelting treatment stage, the element components aluminum, magnesium and silicon in the aluminum alloy single wire are added in the form of single elements, and the element components gadolinium and ytterbium are added in the form of intermediate alloys. Since gadolinium and ytterbium are chemically active, the addition of gadolinium and ytterbium in the form of intermediate alloys can avoid element oxidation and reduce the loss of rare earth elements in the preparation process.

[0026] Specifically, in the smelting treatment stage, the ingredients are aluminum, magnesium and silicon blocks, gadolinium intermediate alloy and ytterbium intermediate alloy; the gadolinium intermediate alloy is Mg-30%Gd alloy, and the ytterbium intermediate alloy is Al-10%Yb alloy. The above ingredients are weighed according to the element component proportion of the aluminum alloy single wire material.

[0027] All the ingredients are put into the crucible of the resistance melting furnace, and all the ingredients are melted into alloy melt at 750-770℃, argon is filled into the alloy melt, and the alloy melt is stirred by using a graphite rod. The stirred and filtered alloy melt is obtained, and the alloy melt is kept at 720-760℃ for 0.5-1h.

[0028] In the continuous casting and rolling stage, the alloy melt after standing is poured into a crystallizer through a flow guide groove in the holding furnace to obtain a casting blank, the pouring speed is 12-15m / min, and the temperature of the casting blank leaving the crystallizer is 460-480℃; the end of the casting blank is sent into a continuous casting and rolling mold after head cutting treatment, and the casting blank is guided out of the mold cavity along the rear end of the mold under the action of the mold rollers, and gradually cooled under the action of the peripheral circulating water system to obtain an aluminum alloy round rod with a diameter of 9.5mm. The open rolling temperature of the casting blank is 510-530℃.

[0029] In the solid solution aging stage, the rolled aluminum alloy round rod is treated by solid solution quenching using a solid solution furnace, the solid solution temperature of the solid solution furnace is 530-560℃, the solid solution holding time is 0.5-3h, and then quenching, the interval time before quenching is ≤10s, and the cooling medium temperature used for quenching is ≤40℃; the aluminum alloy round rod is aged using an aging furnace, the quenched aluminum alloy round rod is put into the aging furnace, the aging temperature of the aging furnace is 120-180℃, the aging holding time is 5-15h, and the aluminum alloy round rod is cooled to room temperature in air after being taken out. The solid solution aging is used to eliminate the primary Mg-Si transition phase β' and promote the precipitation of Mg-Si transition phase β".

[0030] In the drawing forming stage, the aluminum alloy round rod is drawn by nine passes, the diameter is reduced from 9.5mm to 3.44mm to form the alloy wire, the radial deformation of each pass is ≤12%, the drawing speed is 3-8m / s, and the drawing temperature is 35-60℃.

[0031] In the drawing forming stage, the aluminum alloy round rod is drawn by nine passes, the diameter is reduced from 9.5mm to 3.44mm to form the alloy wire, the radial deformation of each pass is ≤12%, the drawing speed is 3-8m / s, and the drawing temperature is 35-60℃.

[0032] Specifically, the aluminum alloy round rod is put into the feeding port of the drawing die of a high-speed drawing machine, under the action of external tension, the aluminum alloy round rod is drawn for nine passes, and the length is increased, and the diameter is gradually reduced from 9.5 mm to 3.44 mm. In order to avoid the fracture caused by excessive deformation of the aluminum alloy round rod, the radial deformation of each pass is not greater than 12%, and the drawing die hole diameter is determined according to the principle of gradually increasing the relative sliding rate from 1.01 to 1.04. In the drawing forming process, the drawing speed is controlled at 3 m / s-8 m / s, and the drawing temperature is controlled at 35℃-60℃.

[0033] In the low-temperature aging stage, the aging temperature of the alloy wire is 110℃-140℃, and the aging holding time is 6h-12h, and then cooled to room temperature. The low-temperature aging stage is used to eliminate the residual stress and dislocation recovery in the alloy wire, so as to further balance the electrical conductivity and mechanical properties of the aluminum alloy single wire material.

[0034] Specifically, the drawn aluminum wire is wound on the wire disc shaft and put into the aging furnace as a whole, the aging furnace is heated to 110℃-140℃, the aging holding time is 6h-12h, then taken out and cooled to room temperature in the air, and the low-temperature aging treatment is completed.

[0035] Based on the above-mentioned different ranges of rare earth element composite modified aluminum alloy single wire material element component ratio and preparation process parameters, the following specific examples are obtained.

[0036] Examples 1-5

[0037] Table 1 is a comparison table of element component ratio of rare earth element composite modified aluminum alloy single wire material in examples 1-5, as follows:

[0038] Table 1

[0039]

[0040] Among them, the balance is aluminum and unavoidable impurity elements.

[0041] Table 2 is a comparison table of the preparation process parameters for rare earth element composite modified aluminum alloy single wire materials in Examples 1-5, as follows:

[0042] Table 2

[0043]

[0044]

[0045] It should be noted that in the drawing stage 3), Examples 1-5 all use drawing dies and wire drawing relative slip ratio for nine-pass drawing. Parameters such as the change in wire drawing die aperture, the relative slip ratio of each wire drawing pass, and the radial deformation of the drawing are all the same, so they are not listed in this table.

[0046] Results Test

[0047] The conductivity and tensile strength of the rare earth element composite modified aluminum alloy single-wire material samples from Examples 1-5 and the comparative example were tested respectively. The results are shown in Table 3.

[0048] Table 3

[0049]

[0050]

[0051] Table 3 compares the conductivity and tensile strength of rare earth element composite modified aluminum alloy single-wire materials in Examples 1-5 and the comparative examples.

[0052] As can be seen from the comparison of the results in Table 3, the single-wire aluminum-magnesium-silicon gadolinium-ytterbium alloy of the present invention has a conductivity of not less than 53% IACS at 20℃, a tensile strength of not less than 360MPa, and an elongation of not less than 6.4%, which are superior to the comparative example in terms of conductivity and mechanical properties.

[0053] like Figure 1 As shown, the microstructure characterization of the rare earth element composite modified aluminum alloy single-wire material of the present invention was performed. Taking the sample results of Example 1 as an example, no slender needle-like β' phase was found in the alloy single-wire sample, while short rod-like β" phase was clearly precipitated. Figure 1 The β" phase (indicated by the middle arrow) has a size in the range of 10nm-20nm and is uniformly and diffusely distributed in the matrix. Compared with the large-sized needle-like transition phase β', the nanoscale transition phase β" can produce a more obvious precipitation strengthening effect, while reducing the scattering of free electrons, thereby synergistically improving the electrical conductivity and mechanical properties of aluminum alloy single wires.

[0054] The modified aluminum alloy single wire material provided by the application has preferably 0.75%-0.90% of magnesium content, 0.50%-0.65% of silicon content, 0.10%-0.30% of gadolinium content and 0.10%-0.30% of ytterbium content. In the content range, the synergistic effect between gadolinium and ytterbium is optimal, both of which are precipitated from the matrix in the same phase form, the dislocation density at the interface between the precipitated phase and the matrix is increased, and the dislocation strengthening effect is more obvious. In addition, magnesium and silicon are precipitated from the matrix in the form of nanoscale transition phase β", the transition phase β" is short and rod-shaped, and is uniformly and dispersedly distributed in the matrix, thereby producing more obvious precipitation strengthening effect. The comprehensive effect of the above two factors can further improve the mechanical properties of the aluminum alloy single wire, and the alloying elements mainly exist in the form of precipitation in the matrix, which can improve the electrical conductivity of the aluminum alloy single wire compared with the solid solution state.

[0055] In conclusion, the rare earth element composite modified aluminum alloy single wire material and the preparation method thereof provided by the application have extremely high electrical conductivity, tensile strength and elongation, and are particularly suitable for the design and manufacture of conductors in overhead transmission lines, especially in heavy icing and large-span transmission lines, can realize the low-loss and high-reliability target of overhead transmission lines, and guarantee the safe and stable operation of overhead transmission lines.

[0056] The above is only an embodiment of the application and is not used to limit the application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application are included in the scope of the claims of the application to be approved.

Claims

1. A rare earth element complex modified aluminum alloy single wire material, characterized by, The element components of the aluminum alloy single-wire material by mass percentage include: 0.65-0.95% of magnesium, 0.50-0.80% of silicon, 0.10-0.50% of gadolinium, 0.10-0.50% of ytterbium, and the balance of aluminum and inevitable impurities.

2. The rare earth element composite modified aluminum alloy single-wire material according to claim 1, characterized in that, the content of magnesium is 0.75-0.90%; and / or the content of silicon is 0.50-0.65%; and / or the content of gadolinium is 0.10-0.30%; and / or the content of ytterbium is 0.10-0.30%.

3. A method of producing a single wire of a rare earth complex modified aluminum alloy according to any one of claims 1 to 2, characterized by, The process includes a smelting stage, continuous casting and rolling, solid solution aging, drawing forming, and a low-temperature aging stage; in the smelting stage, the element components aluminum, magnesium, and silicon in the aluminum alloy single-wire are added in the form of elemental substance, and the element components gadolinium and ytterbium are added in the form of intermediate alloy.

4. The method of producing a rare earth complex modified aluminum alloy single wire material according to claim 3, characterized by, In the smelting stage, the ingredients aluminum, magnesium, and silicon in the form of elemental substance, gadolinium intermediate alloy, and ytterbium intermediate alloy are obtained according to the element component ratio of the aluminum alloy single-wire material; all the ingredients are melted at 750-770°C, and after stirring, the alloy melt is obtained by filtration under an argon atmosphere; the alloy melt is kept at 720-760°C for 0.5-1h.

5. The method for preparing rare earth element composite modified aluminum alloy single-wire material according to claim 4, characterized in that, In the continuous casting and rolling stage, the alloy melt after standing is cast into a crystallizer to obtain a casting blank, the casting speed is 12-15m / min, and the temperature of the casting blank leaving the crystallizer is 460-480°C; the casting blank is subjected to continuous casting and rolling to obtain an aluminum alloy round rod with a diameter of 9.5mm, and the open rolling temperature of the casting blank is 510-530°C.

6. The method of claim 5, wherein the rare earth complex modified aluminum alloy monowire material is prepared by the steps of: preparing a rare earth complex modified aluminum alloy ingot; and performing a single crystal growth process on the rare earth complex modified aluminum alloy ingot. In the solid solution aging stage, the aluminum alloy round rod is subjected to solid solution quenching and aging treatment in sequence; the solid solution temperature of the solid solution quenching is 530-560°C, the solid solution is kept for 0.5-3h before quenching, the interval before quenching is ≤10s, and the cooling medium used for quenching has a temperature of ≤40°C; the aging temperature of the aging treatment is 120-180°C, and the aging keeping time is 5-15h.

7. The method of producing a rare earth complex modified aluminum alloy single wire material according to claim 6, characterized by, In the drawing forming stage, the aluminum alloy round rod is drawn for nine passes, the diameter is reduced from 9.5mm to 3.44mm to form an alloy wire, the radial deformation amount of each pass is ≤12%, the drawing speed is 3-8m / s, and the drawing temperature is 35-60°C.

8. The method of claim 7, wherein the rare earth complex modified aluminum alloy monowire material is prepared by the following steps of: In the drawing forming stage, nine drawing die sets are used, and the hole diameters of the drawing die sets change in sequence as follows: 8.42mm→7.50mm→6.68mm→5.95mm→5.30mm→4.72mm→4.21mm→3.75mm→3.44mm, and the relative sliding rates of each pass are in sequence as follows: 1.01→1.01→1.01→1.015→1.02→1.02→1.03→1.03→1.

04. ​ 9. The method of claim 7, wherein the rare earth complex modified aluminum alloy monowire material is prepared by the steps of: preparing a rare earth complex modified aluminum alloy ingot; and performing a single crystal growth process on the rare earth complex modified aluminum alloy ingot. In the low-temperature aging stage, the aging temperature of the alloy wire is 110-140°C, and the aging keeping time is 6-12h before cooling to room temperature.

10. The method of claim 4, wherein the rare earth complex modified aluminum alloy monowire material is prepared by the steps of: preparing a rare earth complex modified aluminum alloy ingot; and performing a single crystal growth process on the rare earth complex modified aluminum alloy ingot. The gadolinium intermediate alloy uses Mg-30%Gd alloy, and the ytterbium intermediate alloy uses Al-10%Yb alloy.

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