A 6061 aluminum alloy wire rod and its preparation method and application

Abstract

The present invention belongs to the technical field of 6 series aluminum alloys, and specifically relates to a 6061 aluminum alloy wire rod and its preparation method and application. The present invention improves the preparation method and composition of the 6061 aluminum alloy wire rod, and controls the Si / Mg ratio to be greater than 0.75, so that the aluminum alloy material has higher machinability and plasticity. The average grain size of the 6061 aluminum alloy wire rod of the present invention is less than 100 μm, the size of the primary Mg2Si is ≤5 μm, and the precipitated Mg2Si is dispersedly distributed and has a size of 0.1-1 μm. After testing, the tensile strength of the aluminum alloy wire rod of the present invention is 115-130 MPa, the hardness is 35-45 HV, the elongation is ≥35%, and the cold heading deformation is ≥90%, which can meet the application requirements of high-end fasteners for photovoltaic systems.

Description

Technical Field

[0001] The invention belongs to the technical field of 6 series aluminum alloys, and in particular relates to a 6061 aluminum alloy wire rod and a preparation method and application thereof. Background Art

[0002] With the continuous improvement of environmental awareness and the introduction of new energy policies, the photovoltaic industry has gradually become an important part of the global new energy market. The development of the photovoltaic industry will have a profound impact on the relevant industrial chain. Among them, fasteners, as important supporting parts, are also rapidly growing in the photovoltaic industry. In photovoltaic systems, fasteners are used in a complex environment, with large temperature changes and severe oxidation corrosion. Therefore, when selecting fasteners, it is necessary to focus on selecting products with high stability, corrosion resistance and reliability to ensure the safe and reliable operation of the system. Aluminum alloy has become the most ideal material for photovoltaic fasteners due to its light weight, high specific strength, good corrosion resistance, good processing performance and other excellent characteristics.

[0003] Domestic fastener wire rods are generally produced by extrusion-drawing and continuous casting and rolling-drawing. The alloy performance of the extrusion-drawing method is stable but the coil weight is small. Large coil weight has more welded joints, and the production process is long and the cost is high. The continuous casting and rolling-drawing method has large production capacity and high efficiency, but it is difficult to produce high-alloy products, and the material performance fluctuates greatly and the forgeability is poor.

[0004] CN113369331B provides a method for preparing 6061 aluminum alloy round rods, but the elongation of the wire rod prepared by the continuous casting and rolling method in the patent is low (less than 15%), which is difficult to meet the demand for large cold heading deformation of fasteners. CN114892050A provides a 6 series aluminum alloy with high Cu (0.8-0.9wt.%) for fasteners, whose yield strength is 370-410MPa, but the elongation is only 10-15%, which is difficult to meet the demand for high cold heading deformation of fasteners, and high Cu easily leads to poor corrosion resistance. CN112853169A provides a high-strength and high-Cu 6 series aluminum alloy bolt and bolt preparation process. Although the material strength is high, the patent does not mention the elongation and cold heading deformation of the material, and the wire rod is prepared by extrusion + drawing, which is easy to produce coarse grains.

[0005] Therefore, it is necessary to develop an aluminum alloy and its processing technology that are suitable for low-cost, large-scale production of aluminum wire rods for fasteners and have excellent comprehensive performance. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides a 6061 aluminum alloy wire rod and a preparation method and application thereof. The present invention specifically includes the following contents:

[0007] A method for preparing a 6061 aluminum alloy wire rod comprises the following steps:

[0008] S1, homogenization treatment: the 6061 aluminum alloy ingot is heated to 550-570℃ and kept warm. After the insulation is completed, the ingot is cooled with the furnace to ≤300℃ and then cooled with water mist; the water mist cooling (i.e., spray cooling) refers to the technology of online controlled cooling of the aluminum alloy ingot by atomizing water into a mist flow with air at a certain pressure. The main purpose of the homogenization treatment is to make the chemical composition and microstructure of the 6061 aluminum alloy ingot more uniform by heating it to 550-570℃ and keeping it warm. This step helps to eliminate the segregation phenomenon generated by the ingot during the solidification process, reduce internal stress, and improve the overall performance and processability of the material. After the insulation is completed, the ingot is cooled with the furnace to ≤300℃ and then cooled with water mist. A fine and dispersed second phase can be formed during the cooling process, which is used to control the grain size during the subsequent deformation process.

[0009] S2, hot rolling: the 6061 aluminum alloy ingot after homogenization treatment is hot rolled, and the hot rolling process is: hot rough rolling at 480-520℃ to obtain hot rough rolled bars; then hot finish rolling at 400-420℃ to obtain hot finish rolled bars; the main purpose of hot rough rolling at 480-520℃ is to roll the ingot into bars and further improve the microstructure of the material through plastic deformation at high temperature. Hot rough rolling at 480-520℃ helps to reduce the internal defects of the material and improve the density and strength of the material. Subsequently, hot finish rolling is carried out at 400-420℃ to obtain hot finish rolled bars. The main purpose of hot finish rolling is to control the shape and size of the rough rolled bars to obtain more accurate and uniform wire rod sizes. At the same time, hot finish rolling at 400-420℃ also helps to further improve the mechanical properties and surface quality of the material. Moreover, high temperature rolling ensures that the material has high forming properties and ensures that the cold drawing deformation of the final material can reach more than 36%.

[0010] S3, cold drawing: The hot-rolled bar is subjected to 2-3 passes of cold drawing, and the total deformation of the cold drawing is controlled to be ≥36% to obtain a wire rod. Cold drawing is a process of stretching the hot-rolled bar at room temperature. By cold drawing 2-3 times and controlling the deformation of the cold drawing to be ≥36%, the mechanical properties and dimensional accuracy of the material can be significantly improved. During the cold drawing process, the material is subjected to a large tensile force, resulting in plastic deformation, which helps to refine the grains and improve the strength and hardness. At the same time, cold drawing can also reduce the internal defects of the material and improve the fatigue resistance and corrosion resistance of the material.

[0011] S4, annealing: the wire rod obtained by cold drawing is kept at a temperature of 380-420°C, and after the insulation is completed, it is cooled to less than 280°C at a rate of 30-60°C / h to obtain the 6061 aluminum alloy wire rod. This method is a process of cooling the wire rod to less than 280°C at a slower rate (30-60°C / h). The main purpose is to eliminate the internal stress and work hardening phenomenon generated during the cold drawing process, and to restore the plasticity and toughness of the material. Through the annealing process disclosed in the present invention, the microstructure of the wire rod can be made more stable, and its overall mechanical properties and processing properties can be improved. At the same time, it also helps to improve the surface quality and dimensional stability of the wire rod.

[0012] The composition of the 6061 aluminum alloy wire rod includes: Mg 0.8-1.0wt.%, Si 0.6-0.8wt.%, Cu0.15-0.3wt.%, Cr 0.20-0.35wt.%, Mn≤0.15wt.%, Zn≤0.25wt.%, Fe≤0.2wt.%, Ti≤0.1wt.%, the total amount of inevitable impurities ≤0.5wt.% (wt.% in the present invention represents mass percentage), and the balance is Al; wherein Si / Mg≥0.75 (that is, the mass ratio of Si to Mg is not less than 0.75).

[0013] Mg and Si are the main alloying elements in 6 series aluminum alloys, and their contents determine the volume fraction of the strengthening phase in the material and the subsequent strength. The greater the Mg and Si content, the higher the strength. However, if the content is too high, the plasticity / forming properties of the material will be reduced, affecting the subsequent cold drawing and cold heading deformation. At the same time, the Si / Mg ratio will also affect the work hardening ability (deformation / forming ability). The Si / Mg ratio can improve the forming properties of the material within a certain range. In this patent, Mg 0.8-1.0wt.%, Si 0.6-0.8wt.%, and Si / Mg ratio ≥0.75 can ensure that the material has a certain strength and good plasticity, which is conducive to the improvement of the subsequent cold drawing / cold heading performance of the material. The addition of Cu can improve the strength performance and improve the plasticity of the material, but too much Cu will reduce the corrosion resistance of the material, which is not conducive to the use of the material as a fastener. Its content is preferably Cu 0.15-0.3wt.%. In addition, the present invention controls Cr 0.20-0.35wt.% and Mn≤0.15wt.% mainly to control the grain size of the deformed material.

[0014] Furthermore, after the insulation of step S1 is completed, the ingot is first cooled with the furnace to ≤300°C and then cooled with water mist; and / or, the total deformation of the cold drawing in step S3 is ≥45%; and / or, the cooling rate in step S4 is 50-60°C / h; and / or, the Si / Mg in the 6061 aluminum alloy wire rod is 1-0.8.

[0015] Furthermore, the heating rate in step S1 is 20-60°C / h. The purpose of controlling the slow heating to the holding temperature in this step is to fully dissolve the coarse Mg2Si phase formed during the casting process.

[0016] Furthermore, the insulation time in step S1 is 6-12 hours.

[0017] Furthermore, the insulation time in step S4 is 1-2h.

[0018] Furthermore, the specifications of the hot rough rolled bars obtained by the hot rough rolling in step S2 are The specifications of the hot-rolled bars obtained by hot-rolling are

[0019] Furthermore, the specifications of the wire rods obtained in step S3 are of.

[0020] A 6061 aluminum alloy wire rod prepared by the method of the present invention has an average grain size of less than 100 μm, a size of primary Mg2Si of less than 5 μm, and precipitated Mg2Si dispersedly distributed with a size of 0.1-1 μm.

[0021] Furthermore, the 6061 aluminum alloy wire rod prepared by the present invention has a tensile strength of 115-130 MPa, a hardness of 35-45 HV, an elongation of ≥35%, and a cold heading deformation of ≥90%.

[0022] A fastener prepared by using the 6061 aluminum alloy wire rod of the present invention.

[0023] An application of the fastener described in the present invention in a photovoltaic system.

[0024] Beneficial effects of the present invention:

[0025] (1) The preparation method of the 6061 aluminum alloy wire rod disclosed in the present invention is to keep the 6061 aluminum alloy ingot at 550-570°C, and after the heat preservation, cool the ingot with the furnace to ≤300°C and then cool it with water mist. By heating to 550-570°C and keeping it warm, the chemical composition and microstructure in the 6061 aluminum alloy ingot can be made more uniform, which helps to eliminate the segregation phenomenon generated in the solidification process of the ingot, reduce internal stress, and improve the overall performance and processability of the material. After the heat preservation is completed, the ingot is cooled with the furnace to ≤300°C and then cooled with water mist. A fine dispersed second phase can be formed during the cooling process to control the grain size in the subsequent deformation process.

[0026] (2) The 6061 aluminum alloy ingot after homogenization treatment is subjected to hot rough rolling at 480-520°C, and then hot finish rolling at 400-420°C. The main purpose of hot rough rolling at 480-520°C is to roll the ingot into bars and further improve the microstructure of the material through plastic deformation at high temperature, which helps to reduce the internal defects of the material and improve the density and strength of the material. Subsequently, hot finish rolling is carried out at 400-420°C. The main purpose is to control the shape and size of the rough-rolled bars to obtain more accurate and uniform wire rod dimensions. At the same time, it also helps to further improve the mechanical properties and surface quality of the material. Moreover, high-temperature rolling ensures that the material has high formability and ensures that the cold drawing deformation of the final material can reach more than 36%.

[0027] (3) The present invention performs 2-3 passes of cold drawing on the hot-rolled bar, and controls the total deformation of the cold drawing to be ≥36%, which can significantly improve the mechanical properties and dimensional accuracy of the material. During the cold drawing process, the material is subjected to a large tensile force, thereby producing plastic deformation, which helps to refine the grains and improve the strength and hardness. At the same time, cold drawing can also reduce the internal defects of the material and improve the fatigue resistance and corrosion resistance of the material.

[0028] (4) The method cools the wire rod to less than 280°C at a relatively slow rate (30-60°C / h), which can effectively eliminate the internal stress and work hardening phenomenon generated during the cold drawing process, and restore the plasticity and toughness of the material. Through the annealing process disclosed in the present invention, the microstructure of the wire rod can be made more stable, and its overall mechanical properties and processing properties can be improved. At the same time, it also helps to improve the surface quality and dimensional stability of the wire rod.

[0029] (5) While improving the preparation method, the present invention also optimizes the composition of the aluminum alloy wire and controls the Si / Mg ratio to be greater than 0.75, so that the aluminum alloy material has higher machinability and plasticity. Through the improvement of the composition and preparation method, the average grain size of the 6061 aluminum alloy wire rod of the present invention is less than 100μm, the size of the primary Mg2Si is ≤5μm, and the precipitated Mg2Si is dispersed and has a size of 0.1-1μm. After testing, the tensile strength of the aluminum alloy wire rod of the present invention is 115-130MPa, the hardness is 35-45HV, the elongation is ≥35%, and the cold heading deformation is ≥90%, which can meet the application requirements of high-end fasteners for photovoltaic systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a SEM image of the precipitated phase in the 6061 aluminum alloy wire rod prepared in Example 1 of the present invention;

[0031] Figure 2This is a grain structure diagram of a 6061 aluminum alloy wire rod prepared in Example 1 of the present invention;

[0032] Figure 3 This is a photo of the cold heading surface prepared in Example 1 of the present invention;

[0033] Figure 4 This is a photo of the cold heading surface prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0034] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments shown below do not limit the invention content described in the claims. In addition, the entire contents of the structures represented by the following embodiments are not limited to those necessary as solutions to the invention described in the claims.

[0035] A method for preparing a 6061 aluminum alloy wire rod comprises the following steps:

[0036] S1, homogenization treatment: heat the 6061 aluminum alloy ingot to 550-570°C at a heating rate of 20-60°C / h, keep it warm for 6-12h, and after the insulation, cool the ingot to ≤300°C with the furnace and then cool it with water mist;

[0037] S2, hot rolling: the 6061 aluminum alloy ingot after homogenization treatment is subjected to hot rolling, and the hot rolling process is: hot rough rolling at a temperature of 480-520°C to obtain Then hot-rolled at 400-420℃, Hot finished rolled bars;

[0038] S3, cold drawing: the hot finished rolled bar is subjected to 2-3 passes of cold drawing, and the total deformation of the cold drawing is controlled to be ≥36%, and the specification is obtained. of the wire pole;

[0039] S4, annealing: the wire rod obtained by cold drawing is kept at a temperature of 380-420° C. for 1-2 hours, and after the end of the heat preservation, it is cooled to less than 280° C. at a rate of 30-60° C. / h to obtain the 6061 aluminum alloy wire rod;

[0040] The composition of the 6061 aluminum alloy wire rod includes: Mg 0.8-1.0wt.%, Si 0.6-0.8wt.%, Cu0.15-0.3wt.%, Cr 0.20-0.35wt.%, Mn≤0.15wt.%, Zn≤0.25wt.%, Fe≤0.2wt.%, Ti≤0.1wt.%, the total amount of inevitable impurities≤0.5wt.%, and the balance is Al; wherein the Si / Mg ratio is ≥0.75.

[0041] The 6061 aluminum alloy wire rod prepared by the method has an average grain size of less than 100 μm, a size of primary Mg2Si of ≤5 μm, a dispersed distribution of precipitated Mg2Si with a size of 0.1-1 μm, a tensile strength of 115-130 MPa, a hardness of 35-45 HV, an elongation of ≥35%, and a cold heading deformation of ≥90%.

[0042] Example 1

[0043] The aluminum alloy components are, by mass percentage, Mg 0.8wt.%, Si 0.6wt.%, Mn 0.15wt.%, Cu 0.15wt.%, Ti 0.1wt.%, Fe 0.2wt.%, Cr 0.2wt.%, Zn 0.25wt.%, and the balance is aluminum and inevitable impurities.

[0044] The above alloy components are cast into The ingot was heated to 550℃ at a rate of 30℃ / h and kept at this temperature for 12h. After the incubation, the ingot was cooled to 300℃ and then cooled with water mist. The ingot after homogenization was milled and then heated to 520℃ and hot rolled to The bars are then hot rolled at 420°C. Rod; then pull the rod to Wire rod. The finished annealing system of the wire rod is 380℃ / 1h, and then cooled to 260℃ at a rate of 60℃ / h.

[0045] Example 2

[0046] The aluminum alloy components are, by mass percentage, Mg 0.9wt.%, Si 0.8wt.%, Mn 0.08wt.%, Cu 0.3wt.%, Ti 0.05wt.%, Fe 0.15wt.%, Cr 0.35wt.%, Zn 0.05wt.%, and the balance is aluminum and inevitable impurities.

[0047] The above alloy components are cast into The ingot was heated to 565℃ at a rate of 30℃ / h and kept at this temperature for 8h. After the ingot was cooled to 290℃, it was cooled with water mist. The ingot was milled after homogenization treatment, and then heated to 480℃ and hot rolled to The bars are then hot rolled at 400℃ to The rod is pulled to Wire rod. The finished annealing system of wire rod is 400℃ / 1h, and then cooled to 280℃ at 50℃ / h.

[0048] Example 3

[0049] The aluminum alloy components are, in mass percentage, Mg 1.0wt.%, Si 0.77wt.%, Mn 0.12wt.%, Cu 0.25wt.%, Ti 0.06wt.%, Fe 0.1wt.%, Cr 0.26wt.%, Zn 0.1wt.%, and the balance is aluminum and inevitable impurities.

[0050] The above alloy components are cast into The ingot was heated to 570℃ at a rate of 50℃ / h and kept at this temperature for 6h. After the incubation, the ingot was cooled to 280℃ with the furnace and then cooled with water mist. The ingot after homogenization was milled and heated to 480℃ and hot rolled to The bars are then hot rolled at 420°C. The rod is pulled to Wire rod. The finished annealing system of the wire rod is 420℃ / 1h, and then cooled to 260℃ at a rate of 60℃ / h.

[0051] Example 4

[0052] The aluminum alloy components are, by mass percentage, Mg 0.9wt.%, Si 0.7wt.%, Mn 0.1wt.%, Cu 0.25wt.%, Ti 0.1wt.%, Fe 0.15wt.%, Cr 0.28wt.%, Zn 0.15wt.%, and the balance is aluminum and unavoidable impurities.

[0053] The above alloy components are cast into The semi-continuous ingot was heated to 560℃ at a rate of 30℃ / h and kept at this temperature for 10h. After the incubation, the ingot was cooled to 260℃ with the furnace and then cooled with water mist. The ingot after homogenization treatment was milled and heated to 520℃ and hot rolled to The bars are then hot rolled at 420°C. The rod is pulled to Wire rod. The finished annealing system of the wire rod is 380℃ / 1h, and then cooled to 260℃ at a rate of 60℃ / h.

[0054] Example 5

[0055] The aluminum alloy components are, in mass percentage, Mg 0.84wt.%, Si 0.63wt.%, Mn 0.08wt.%, Cu 0.26wt.%, Ti 0.08wt.%, Fe 0.15wt.%, Cr 0.30wt.%, Zn 0.05wt.%, and the remainder is aluminum and inevitable impurities.

[0056] The above alloy components are cast into The semi-continuous ingot was heated to 550℃ at a rate of 60℃ / h and kept at this temperature for 12h. After the incubation, the ingot was cooled to 250℃ with the furnace and then cooled with water mist. The ingot after homogenization treatment was milled and heated to 520℃ for hot rolling. The bars are then hot rolled at 420°C. The rod is pulled to Wire rod. The finished annealing system of the wire rod is 400℃ / 1h, and then cooled to 260℃ at a rate of 60℃ / h.

[0057] Example 6

[0058] The aluminum alloy components are, in mass percentage, Mg 0.9wt.%, Si 0.7wt.%, Mn 0.05wt.%, Cu 0.16wt.%, Ti 0.04wt.%, Fe 0.1wt.%, Cr 0.22wt.%, Zn 0.15wt.%, and the balance is aluminum and inevitable impurities.

[0059] The above alloy components are cast into The semi-continuous ingot was heated to 555℃ at a rate of 40℃ / h and kept at this temperature for 9h. After the incubation, the ingot was cooled to 300℃ with the furnace and then cooled with water mist. The ingot after homogenization treatment was milled and heated to 500℃ and hot rolled to The bars are then hot rolled at 410°C. Rod. After 2 passes, the rod is pulled to Wire rod. The finished annealing system of the wire rod is 390℃ / 2h, and then cooled to 250℃ at a rate of 40℃ / h.

[0060] Example 7

[0061] The aluminum alloy components are, by mass percentage, Mg 0.85wt.%, Si 0.65wt.%, Mn 0.1wt.%, Cu 0.20wt.%, Ti 0.06wt.%, Fe 0.09wt.%, Cr 0.28wt.%, Zn 0.25wt.%, and the balance is aluminum and unavoidable impurities.

[0062] The above alloy components are cast into The semi-continuous ingot was heated to 570℃ at a rate of 20℃ / h and kept at this temperature for 12h. After the incubation, the ingot was cooled to 270℃ with the furnace and then cooled with water mist. The ingot after homogenization treatment was milled and heated to 510℃ and hot rolled to The bars are then hot rolled at 415°C Rod. After 2 passes, the rod is pulled to Wire rod. The finished annealing system of the wire rod is 410℃ / 2h, and then cooled to 250℃ at a rate of 30℃ / h.

[0063] Comparative Example 1

[0064] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0065] The above alloy components are cast into The semi-continuous ingot is heated to 540℃ and kept for 20 hours. After the heat preservation, the ingot is cooled to 300℃ with the furnace and then cooled with water mist. The ingot after homogenization treatment is milled and heated to 500℃ and hot rolled to The bars are then hot rolled at 420°C. Rod. After 2 passes, the rod is pulled to Wire rod. The finished annealing system of the wire rod is 420℃ / 1h, and then cooled to 260℃ at a rate of 60℃ / h.

[0066] Comparative Example 2

[0067] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0068] The above alloy components are cast into The semi-continuous ingot is heated to 540℃ and kept for 20 hours. After the heat preservation, the ingot is cooled to 300℃ with the furnace and then cooled with water mist. The ingot after homogenization treatment is milled and heated to 500℃ and hot rolled to The bars are then hot rolled at 420°C. After intermediate annealing at 420℃ / 1h, the bar is drawn to Wire rod. The finished annealing system of the wire rod is 400℃ / 1h, and then cooled to 260℃ at a rate of 60℃ / h.

[0069] Comparative Example 3

[0070] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0071] The above alloy components are cast into The semi-continuous ingot is heated to 540℃ and kept for 20 hours. After the heat preservation, the ingot is cooled to 300℃ with the furnace and then cooled with water mist. The ingot after homogenization treatment is milled and heated to 500℃ and hot rolled to The bars are then hot rolled at 420°C. The rod is pulled to Wire rod. The finished product annealing system of wire rod is 450℃ / 1h, air cooling.

[0072] Comparative Example 4

[0073] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0074] The difference between the preparation method and Example 1 is that after the homogenization and heat preservation are completed, the furnace is directly cooled, and other process conditions are the same.

[0075] Comparative Example 5

[0076] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0077] The difference between the preparation method and Example 1 is that water mist cooling is directly performed after homogenization and heat preservation, and other process conditions are the same.

[0078] Comparative Example 6

[0079] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0080] The difference between the preparation method and Example 1 is that the homogenization heating rate is 80°C / h, the insulation system is 590°C×5h, and the other process conditions are the same.

[0081] Comparative Example 7

[0082] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0083] The difference between the preparation method and Example 1 is that the homogenization heating rate is 15°C / h, the insulation system is 540°C×15h, and the other process conditions are the same.

[0084] Comparative Example 8

[0085] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0086] The difference between the preparation method and Example 1 is that the hot rough rolling is carried out at a temperature of 530° C., and then the hot finish rolling is carried out at a temperature of 450° C., and the other process conditions are the same.

[0087] Comparative Example 9

[0088] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0089] The difference between the preparation method and Example 1 is that the hot rough rolling is carried out at 460° C., and then the hot finish rolling is carried out at 390° C., and the other process conditions are the same.

[0090] Comparative Example 10

[0091] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0092] The difference between the preparation method and Example 1 is that the cooling rate after the annealing and heat preservation is 80° C. / h, and the other process conditions are the same.

[0093] Comparative Example 11

[0094] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0095] The difference between the preparation method and Example 1 is that the cooling rate after the annealing and heat preservation is 20° C. / h, and the other process conditions are the same.

[0096] Comparative Example 12

[0097] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0098] The difference between the preparation method and Example 1 is that the annealing temperature is 440° C., and the other process conditions are the same.

[0099] Comparative Example 13

[0100] The aluminum alloy composition of this comparative example is consistent with that of Example 1.

[0101] The difference between the preparation method and Example 1 is that the annealing temperature is 370° C., and the other process conditions are the same.

[0102] Comparative Example 14

[0103] The preparation method of this comparative example is the same as that of Example 1, and the components of the aluminum alloy are, by mass percentage, Mg 1.0wt.%, Si 0.6wt.%, Mn 0.15wt.%, Cu 0.15wt.%, Ti 0.1wt.%, Fe 0.2wt.%, Cr 0.2wt.%, Zn 0.25wt.%, and the remainder is aluminum and unavoidable impurities.

[0104] The aluminum alloy wire rods prepared in the examples and comparative examples were subjected to performance tests and microstructure characterization, and the results are shown in Tables 1-2 and the accompanying drawings. Figure 1 This is a SEM image of the precipitated phase in the 6061 aluminum alloy wire rod prepared in Example 1 of the present invention; Figure 2 This is a grain structure diagram of a 6061 aluminum alloy wire rod prepared in Example 1 of the present invention;

[0105] Figure 3 This is a photo of the cold heading surface prepared in Example 1 of the present invention; Figure 4 This is a photo of the cold heading surface prepared in Comparative Example 1 of the present invention.

[0106] Table 1 Performance of finished wire rods in the embodiments and comparative examples

[0107]

[0108]

[0109] Table 2 Microstructure characteristics of finished wire rods in the embodiments and comparative examples

[0110]

[0111]

[0112] The average grain size distribution of the alloys of Examples 1-7 is in the range of 35-52 μm, and the Mg2Si phase is sufficiently precipitated, which can ensure that the alloy sheet has good formability and surface quality.

[0113] In Comparative Example 1, due to the small amount of cold drawing, recrystallization is difficult to occur during the annealing process, resulting in abnormally coarse grains, and the alloy plasticity and cold heading performance are significantly reduced. In Comparative Example 2, because of the addition of hot rolling annealing, the alloy strength is reduced, the grain size is increased, and the cold heading performance is reduced. In Comparative Example 3, due to the fast cooling rate after the finished product annealing, the dispersed Mg2Si / Si phase has no time to precipitate, resulting in higher alloy strength and reduced plasticity, resulting in poor cold heading performance. Comparative Examples 4-13 all fail to meet the requirements of the present invention because the preparation process or composition does not meet the requirements of the present invention.

[0114] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a 6061 aluminum alloy wire rod, characterized in that: The following steps are involved: S1, homogenization treatment: the 6061 aluminum alloy ingot is heated to 550-570℃ and kept warm. After the heat preservation, the ingot is cooled to ≤300℃ and then cooled by water mist; S2, hot rolling: hot rolling the 6061 aluminum alloy ingot after homogenization treatment, wherein the hot rolling process comprises: hot rough rolling at a temperature of 480-520° C. to obtain hot rough rolled bars; Then hot-rolling is performed at 400-420°C to obtain hot-rolled bars; S3, cold drawing: cold drawing the hot finished rolled bar for 2-3 passes, controlling the total deformation of the cold drawing to be ≥36%, to obtain a wire rod; S4, annealing: the wire rod obtained by cold drawing is kept at a temperature of 380-420° C., and after the end of the heat preservation, it is cooled to less than 280° C. at a rate of 30-60° C. / h to obtain the 6061 aluminum alloy wire rod; The composition of the 6061 aluminum alloy wire rod includes: Mg 0.8-1.0wt.%, Si 0.6-0.8wt.%, Cu0.15-0.3wt.%, Cr 0.20-0.35wt.%, Mn≤0.15wt.%, Zn≤0.25wt.%, Fe≤0.2wt.%, Ti≤0.1wt.%, the total amount of inevitable impurities≤0.5wt.%, and the balance is Al; wherein Si / Mg≥0.

75.

2. The method for preparing a 6061 aluminum alloy wire rod according to claim 1, characterized in that: After the insulation in step S1 is completed, the ingot is first cooled with the furnace to ≤300°C and then cooled with water mist; and / or, the total deformation of the cold drawing in step S3 is ≥45%; and / or, the cooling rate in step S4 is 50-60°C / h; and / or, the Si / Mg in the 6061 aluminum alloy wire rod is 1-0.

8.

3. The method for preparing a 6061 aluminum alloy wire rod according to claim 1, characterized in that: The heating rate in step S1 is 20-60° C. / h; and / or, the insulation time in step S1 is 6-12 h.

4. The method for preparing a 6061 aluminum alloy wire rod according to claim 1, characterized in that: The insulation time in step S4 is 1-2h.

5. The method for preparing a 6061 aluminum alloy wire rod according to any one of claims 1 to 4, characterized in that: The specification of the hot rough rolled bar obtained by the hot rough rolling in step S2 is φ18-22 mm; the specification of the hot finish rolled bar obtained by the hot finish rolling is φ10-13.8 mm.

6. The method for preparing a 6061 aluminum alloy wire rod according to claim 5, characterized in that: The specification of the wire rod obtained in step S3 is φ8~10.2mm.

7. A 6061 aluminum alloy wire rod prepared by the method according to any one of claims 1 to 6, characterized in that: The average grain size is less than 100 μm, the size of primary Mg2Si is ≤5 μm, and the precipitated Mg2Si is dispersed and has a size of 0.1-1 μm.

8. The 6061 aluminum alloy wire rod according to claim 7, characterized in that: Its tensile strength is 115-130MPa, hardness is 35-45HV, elongation is ≥35%, and cold heading deformation is ≥90%.

9. A fastener made from the 6061 aluminum alloy wire rod according to claim 8.

10. Use of the fastener according to claim 9 in a photovoltaic system.

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