A Short-Process Preparation Method for Aluminum-Magnesium-Silicon Alloy Conductors

Abstract

This invention relates to a short-process manufacturing method for aluminum-magnesium-silicon alloy wire rods, comprising steps including direct cooling continuous casting of wire rod blanks, multi-pass small-deformation roll cold rolling, single-pass precision drawing, and artificial aging treatment. The invention first uses direct cooling continuous casting to obtain small-diameter aluminum alloy wire rod blanks, effectively improving the compositional segregation commonly seen in casting. Multi-pass small-deformation roll cold rolling enhances its machinability. Single-pass precision drawing yields a uniform, extremely fine fibrous structure and wire with extremely high solid solubility, thereby effectively improving the alloy's aging strengthening effect and synergistically increasing the strength and conductivity of the aluminum alloy wire rods. This invention eliminates the need for heat treatment (solution and annealing) or hot working processes required in traditional continuous casting or continuous casting-rolling methods for producing aluminum alloy wire rods. While ensuring the matching of the wire's mechanical and electrical properties, it simplifies the entire production process operation and control, thereby stabilizing product quality, improving production efficiency, and reducing costs.

Description

Technical Field

[0001] This invention relates to the field of metal plastic processing technology, and specifically to a short-process method for preparing aluminum-magnesium-silicon alloy wires. Background Technology

[0002] Aluminum-magnesium-silicon alloys (typically 6101 and 6201) have a high combination of strength and conductivity, and are widely used in the development of high-performance aluminum alloy conductors. For aluminum-magnesium-silicon alloy conductors, there are currently three main production processes based on continuous casting and rolling + multi-pass stretching: (1) Traditional production process: continuous casting and rolling, solution treatment and quenching, stretching, and aging treatment; (2) Semi-continuous production process: continuous casting and rolling, solution treatment, stretching, and aging treatment; (3) Continuous thermomechanical treatment production process: continuous casting and controlled rolling online solution treatment, controlled stretching and online aging. Solution treatment is a key process that affects the matching of mechanical and electrical properties of alloy conductors (generally, the higher the conductor strength, the lower the conductivity, and matching means that the conductor has both high strength and conductivity). Continuous casting and rolling is the main method for producing aluminum and soft aluminum alloy wire blanks in the wire and cable industry. Its process flow is: batching → melting → refining → continuous casting → hot rolling → wire rod blank with a diameter of about 9.5 mm. However, since continuous casting and rolling connect continuous casting and hot rolling, it is necessary to ensure both castability and hot rolling machinability. The usual practice is to reheat the cast trapezoidal bars before they enter the rolling mill to ensure that the hot-rolled wire rod billets are in a solution-treated state. This method increases the complexity of the process and the difficulty of operation and control.

[0003] Direct water-cooled continuous casting and horizontal continuous casting are also methods for preparing aluminum alloy wire rod blanks. The process flow is: batching → melting → refining → horizontal continuous casting → wire rod blank. Invention patent 201010593503.6 provides a high-conductivity, heat-resistant aluminum alloy wire and its preparation method. The aluminum alloy wire is manufactured through processes such as aluminum ingot melting, "boroning" treatment, refining, alloying, secondary refining, direct water-cooled continuous casting, annealing, drawing, and stabilization treatment. However, common problems such as specific gravity segregation, dendrite segregation, grain boundary segregation, and regional segregation inevitably occur in horizontally continuously cast aluminum alloy wire rod blanks. These segregations are difficult to eliminate in subsequent drawing processes, and homogenization treatment of the horizontally continuously cast aluminum alloy wire rod blank is usually necessary. Furthermore, since horizontally continuously cast wire rods are essentially a cast structure with poor plasticity, they are prone to wire breakage during subsequent drawing. They typically require intermediate annealing (but the annealing temperature is lower than the solution temperature, causing the precipitation of Mg2Si strengthening phases during annealing, significantly reducing the age-hardening effect; therefore, a solution quenching treatment is necessary afterward). Therefore, this process is not suitable for the production of heat-treatable aluminum-magnesium-silicon alloy wires. Invention patent ZL201210328680.0 proposes a method for manufacturing aluminum-magnesium-silicon alloy wires, comprising processes such as horizontal continuous casting of aluminum alloys, continuous extrusion, online quenching and stretching, and artificial aging. This process suffers from the same problems as invention CN201010593503.6.

[0004] In summary, traditional continuous casting and rolling or continuous casting-drawing methods for producing aluminum alloy wires all require heat treatment (solution and annealing) or hot working processes. Therefore, researchers still need to develop new, low-cost, low-energy-consumption, short-process manufacturing methods to ensure a balance between the mechanical and electrical properties of aluminum alloy wires. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the technical problems in existing aluminum-magnesium-silicon alloy wire production processes, such as the need for heat treatment (solution and annealing) or hot working, the tendency for segregation in horizontal continuous casting, and the difficulty in process control, which affects the matching of mechanical and electrical properties of the wire products, this invention proposes a new short-process preparation method for aluminum-magnesium-silicon alloy wires. This method eliminates the need for heat treatment (solution and annealing) or hot working in traditional continuous casting or continuous casting-rolling methods for producing aluminum alloy wires, making process operation and control simpler, improving production efficiency, and reducing production costs.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0009] In a first aspect, the present invention provides a short-process method for preparing aluminum-magnesium-silicon alloy wires, which consists of the following four steps performed in sequence:

[0010] S1, Aluminum Alloy Wire Rod Billet Direct Cooling Continuous Casting

[0011] The alloy melt obtained by smelting is used as a mold by direct cooling continuous casting to obtain a small diameter aluminum alloy wire rod blank; the melt flows out from the hole with a diameter of 7-9 mm on the plate, and the melt is directly cooled and solidified with water at the outlet of the hole to obtain the small diameter aluminum alloy wire rod blank with a diameter of 7-9 mm.

[0012] S2, multi-pass small deformation roll cold continuous rolling

[0013] The small-diameter aluminum alloy wire rod blank is subjected to multi-pass cold continuous rolling with small deformation to obtain wire with a target diameter of 1.05-1.2 times, and the deformation of each rolling pass is controlled at 5-10%.

[0014] S3, Single-pass sub-precision pulling

[0015] The wire obtained by S2 is precision drawn to the target diameter of the product in a single pass;

[0016] S4. Artificial Aging Processing

[0017] The wires made from S3 are kept at 115-145℃ for 6-12 hours.

[0018] In step S4, since rapid cooling during casting can form a high solid solubility microstructure, followed by cold working deformation, this will produce a cold working fibrous microstructure with extremely high dislocation density, giving the alloy microstructure extremely high deformation energy storage, which is conducive to accelerating deformation and improving aging effect. Therefore, compared with traditional aging conditions, the aging temperature can be reduced and the time shortened.

[0019] According to a preferred embodiment of the present invention, in S1, the direct cooling continuous casting is a multi-flow direct cooling continuous casting, specifically, the melt is divided into 16-32 flows; the plate hole is a high-temperature resistant inert material plate hole. Multi-flow direct cooling continuous casting can improve casting efficiency, thus solving the problem of low casting efficiency for "small diameter" products.

[0020] According to a preferred embodiment of the present invention, in S1, the plate hole is an asbestos plate with holes, and the number of holes is the same as the number of melt flows; a water spraying device is provided at the top of the outlet of the hole, and the water sprayed by the water spraying device directly cools and solidifies the melt flowing out of the hole into a rod blank.

[0021] In addition, S1 also includes batching according to the alloy composition and then melting to obtain an alloy melt.

[0022] According to a preferred embodiment of the present invention, in S1, the pouring temperature is controlled at 680-690℃, and the casting speed is 500-600mm / min. If the pouring temperature is too high or the speed is too fast, the casting will not form properly; if the pouring temperature is too low, the flow will be obstructed, and the casting will easily break.

[0023] According to a preferred embodiment of the present invention, in S3, a coil drawing machine is used to perform a single-pass precision drawing on the wire obtained in S2. This precision drawing is used to meet the dimensional accuracy requirements of the final conductor product.

[0024] According to a preferred embodiment of the present invention, in S4, the artificial aging treatment adopts a box-type hot air circulating electric furnace.

[0025] (III) Beneficial Effects of the Invention

[0026] The method for preparing aluminum-magnesium-silicon alloy wires provided by this invention is based on the following idea: first, a small-diameter aluminum alloy wire rod blank is obtained by direct cooling continuous casting process; then, it is subjected to multi-pass small deformation roll cold continuous rolling to improve its processing performance (providing conditions for subsequent precision drawing); and finally, after single-pass precision drawing, a uniform and consistent ultra-fine fibrous structure and wire with extremely high solid solubility are obtained, thereby effectively improving the alloy aging strengthening effect and achieving the technical effect of synergistically improving the strength and conductivity of aluminum alloy wires.

[0027] Among them, since the diameter of the aluminum alloy wire rod blank obtained by the direct cooling continuous casting process is very small, the cooling rate is inevitably very fast. Therefore, compared with the traditional continuous casting process, it can effectively improve the problem of compositional segregation that is common in the casting process. At the same time, it is combined with multi-pass small deformation type roll cold continuous rolling to improve its processing performance.

[0028] The manufacturing process of this invention eliminates the need for heat treatment (solution and annealing) or hot working processes required in the traditional continuous casting or continuous casting and rolling methods for producing aluminum alloy wires. Under the premise of ensuring the matching of mechanical and electrical properties of aluminum alloy wires, the entire production process is simpler to operate and control, thereby stabilizing product quality, improving production efficiency and reducing costs.

[0029] This invention provides a novel short-process manufacturing process for aluminum-magnesium-silicon alloy wires, which can be applied to the development and production of special aluminum alloy wires. Detailed Implementation

[0030] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to specific embodiments.

[0031] The following embodiments use typical 6201 aluminum alloy wires as examples to illustrate the features and technical effects of the present invention.

[0032] Examples 1-8

[0033] Based on the standard chemical composition of the alloy, 99.7 aluminum ingots, magnesium ingots, and Al-30Si master alloy were used to prepare the aluminum alloy according to the designed weight ratio and feeding rules. The alloy was melted in a dual 500Kg capacity gas-fired melting furnace. After degassing and slag removal refining treatment, the melt was sampled and chemically analyzed using a direct reading spectral method. The measured composition is shown in Table 1.

[0034] Table 1. Main chemical composition (weight percentage, %) of the 6201 aluminum alloy of this invention

[0035] alloy Si Fe Cu Mn Mg Cr Zn B standard 0.50-0.95 ≤0.50 ≤0.10 ≤0.03 0.60-0.90 ≤0.03 ≤0.10 ≤0.06 Actual measurement 0.682 0.124 0.023 0.006 0.721 0.003 0.061 0.016

[0036] After heat preservation and filtration, the material is continuously cast into round wire rods with a diameter of Ф7.5mm using a 16-strand direct cooling system. The casting temperature is controlled at 680-690℃, and the casting speed is approximately 550mm / min. The Ф7.5mm diameter round wire rod billets are then cold-rolled on a 15-stand continuous rolling mill into wires with diameters of Ф3.8mm, Ф3.5mm, Ф3.2mm, and Ф2.8mm (the wire diameter is varied by adjusting the height of the subsequent stand rolls), with a deformation of 5-6% per pass. These are then precision drawn on a 600-type coil drawing machine to produce conductor products with finished diameters of Ф3.58mm, Ф3.22mm, Ф3.02mm, and Ф2.65mm. The wires are then loosely wound into coils and subjected to artificial aging treatments in a 110KW box-type resistance furnace, holding at 120℃ for 12 hours and at 135℃ for 8 hours respectively. The measured mechanical and electrical properties of the aluminum alloy conductors are shown in Table 2.

[0037] Table 2 Comparison of test results of mechanical and electrical properties of the 6201 aluminum alloy wire of the present invention

[0038]

[0039] The measurement results in the table above show that the tensile strength of the conductors in Examples 1-8 is between 311.7-320.8 MPa, the elongation is between 3.4-4.6%, and the conductivity at 20℃ (% IACS) is between 55.3-56.2. Therefore, the mechanical and electrical properties of the 6201 aluminum alloy conductor of this invention meet the requirements of standard ASTM B 398-02 Electrical 6201-T81 aluminum alloy wire (standard: tensile strength 295-300 MPa, elongation 3.0-3.5%, conductivity 52.5-53.0% IACS).

[0040] Furthermore, according to verification, the existing method for manufacturing aluminum-magnesium-silicon alloy conductors proposed in CN102828130B produces products with the following performance characteristics:

[0041] Example Product tensile strength / MPa Elongation / % 1 291 5 2 305 6 3 294 6 4 296 7 5 289 8 6 316 6 7 320 6 8 331 5

[0042] Comparison shows that the tensile strength of the conductors prepared in the embodiments of the present invention is between 311.7-320.8 MPa (none of which is lower than 300 MPa), and the overall tensile strength of the products is better than that of the prior art; and in terms of conductor elongation, the elongation of the aluminum alloy conductors prepared in the present invention is closer to the standard requirement range.

[0043] More importantly, this invention utilizes a direct cooling continuous casting-multi-pass small deformation roll cold continuous rolling process, eliminating the need for heat treatment (solution and annealing) or hot working steps required in traditional continuous casting or continuous casting-rolling methods for producing aluminum alloy wires. Therefore, it is a novel short-process manufacturing method for aluminum-magnesium-silicon alloy wires that is simple to operate, highly efficient, and low in cost.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A short process production method of an aluminum-magnesium-silicon alloy wire, characterized by, It consists of the following four steps performed in sequence: S1, Aluminum Alloy Wire Rod Billet Direct Cooling Continuous Casting The alloy melt obtained by smelting is used as a mold by direct cooling continuous casting to obtain a small diameter aluminum alloy wire rod blank; the melt flows out from the hole with a diameter of 7-9 mm on the plate, and the melt is directly cooled and solidified with water at the outlet of the hole to obtain the small diameter aluminum alloy wire rod blank with a diameter of 7-9 mm. S2, multi-pass small deformation roll cold continuous rolling The small-diameter aluminum alloy wire rod blank is subjected to multi-pass cold continuous rolling with small deformation to obtain wire with a target diameter of 1.05-1.2 times, and the deformation of each rolling pass is controlled at 5-10%. S3, Single-pass sub-precision pulling The wire obtained by S2 is precision drawn to the target diameter of the product in a single pass; S4. Artificial Aging Processing The wires made from S3 are kept at 115-145℃ for 6-12 hours.

2. The short process production method of an aluminum-magnesium-silicon alloy wire according to claim 1, characterized by, In S1, the direct cooling continuous casting is a multi-flow direct cooling continuous casting, specifically dividing the melt into 16-32 flows; the plate hole is a plate hole made of a high-temperature resistant inert material.

3. The short process production method of an aluminum-magnesium-silicon alloy wire according to claim 2, characterized by, In S1, the plate hole is an asbestos plate with holes, and the number of holes is the same as the number of melt flows; a water spraying device is provided at the top of the hole outlet, and the water sprayed by the water spraying device will directly cool and solidify the melt flowing out of the hole into a rod blank.

4. The short process production method of an aluminum-magnesium-silicon alloy wire according to claim 1, characterized by, In S1, the pouring temperature is controlled at 680-690℃, and the casting speed is 500-600mm / min.

5. The short-process preparation method for aluminum-magnesium-silicon alloy wires according to claim 1, characterized in that, In S3, a coil drawing machine is used to perform single-pass precision drawing on the wire produced in S2.

6. The short-process preparation method for aluminum-magnesium-silicon alloy wires according to claim 1, characterized in that, In S4, the artificial aging process uses a box-type hot air circulating electric furnace.

Images