High-performance low-carbon secondary aluminum extruded profile and preparation method thereof

Abstract

The invention belongs to the technical field of regenerated aluminum alloy extruded profiles, and particularly relates to a high-performance low-carbon regenerated aluminum extruded profile and a preparation method thereof, when the total amount of Mg2si is controlled to be 0.79% and the silicon content is 0.1%, the mechanical property sigma b of the alloy is about 218Mpa, the excess silicon content is increased from 0.1% to 0.13%, the sigma b can be increased to 250Mpa, namely 14.6%, and in order to form a certain amount of Mg2Si, the mechanical property sigma b can be increased by 14.6%. Firstly, silicon loss caused by the content of impurities such as Fe and Mn is considered, the total amount of Mg2si is controlled to be 0.79%, the content of silicon is controlled, the tensile strength and the yield strength of the alloy are improved, the extrusion speed can be increased in cooperation with aluminum alloy homogenizing annealing, and compared with a cast ingot subjected to non-homogenizing annealing, the extrusion force can be reduced by about 6%-10%, and the yield of the cast ingot is increased by about 6%-10%. A closed-loop system is formed by adjusting and controlling the extrusion temperature, the extrusion speed and the extrusion force in the extrusion process, so that the extrusion speed and the production efficiency are improved to the maximum extent, and meanwhile the optimal performance is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of recycled aluminum alloy extruded profiles, and in particular relates to a high-performance low-carbon recycled aluminum extruded profile and a preparation method thereof. Background Art

[0002] At present, all countries are vigorously developing and promoting new energy vehicles, photovoltaic power generation equipment, etc. Taking new energy vehicles as an example, in recent years, the production and sales volume has increased rapidly, and the overall strength has been significantly improved, which has effectively promoted the reduction of carbon emissions during the use of automobiles. With the rapid development of energy-saving and new energy vehicles, the application of lightweight aluminum alloy structural parts has played an increasingly important role in improving the performance and competitiveness of automobile products. However, structural parts have strict requirements on material properties, and electrolytic aluminum must be used for smelting and subsequent processing, resulting in high carbon emissions in the acquisition stage of parts and complete vehicle raw materials, and the extrusion molding efficiency of aluminum profiles is low, revealing a prominent problem that is contrary to the overall goal of energy conservation and emission reduction. It is urgent to promote the low-carbon development of aluminum materials and automobile products through technological innovation. Summary of the invention

[0003] In order to solve the problems raised in the above background technology, the present invention provides a high-performance low-carbon recycled aluminum extrusion profile and a preparation method thereof, which has the characteristics of improving molding efficiency.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a high-performance low-carbon recycled aluminum extrusion profile and a preparation method thereof, wherein the total amount of Mg2Si is controlled at 0.79%, and when the silicon excess is 0.1%, the mechanical property σb of the alloy is about 218Mpa, which has greatly exceeded the national standard performance, and when the excess silicon is increased from 0.1% to 0.13%, σb can be increased to 250Mpa, that is, an increase of 14.6%. To form a certain amount of Mg2Si, the silicon loss caused by the impurity content such as Fe and Mn must first be considered, that is, a certain amount of excess silicon must be guaranteed. In order to make the magnesium in the alloy fully match the silicon, when actually mixing the ingredients, Mg:Si<1.73 must be consciously made, and the chemical composition mass percentage is: Mg: 0.65%-0.85%; Si: 0.35%-0.50%; Mg:Si=1.3-2.4; the impurity Fe is controlled to be <0.10%-0.25%; Mn<0.10%.

[0005] Preferably, a method for preparing a high-performance low-carbon recycled aluminum extruded profile comprises the following steps:

[0006] Step 1: Alloy smelting: Raise the furnace temperature to not less than 700°C, put recycled aluminum, intermediate alloy containing required elements and a small amount of pure aluminum into the furnace in batches for melting, and after complete melting, refine and degasify to obtain a primary aluminum melt.

[0007] Step 2: Alloy refining: Sampling and analyzing the aluminum melt, adding metal elements or intermediate alloys to adjust the aluminum melt to the target composition of the aluminum alloy, and after refining and degassing, obtaining a refined alloy melt with the desired target composition.

[0008] Step 3: Ingot casting: The refined melt obtained in step 2 is used to prepare an aluminum alloy ingot of target composition by a semi-continuous casting method.

[0009] Step 4: Homogenizing annealing of ingot: Homogenizing annealing is carried out at a temperature of 560+20°C, and the temperature is kept for 4-6 hours. The cooling method is forced air cooling or water spraying rapid cooling.

[0010] Step 5: Extrusion and shaping: Heat the ingot at a temperature of 430-480°C, preheat the extrusion die, and extrude at a speed of 20-100 m / min. At the same time, in order to prevent extrusion cracks, the extrusion speed should be gradually reduced as the extrusion process proceeds and the temperature of the deformation zone increases.

[0011] Step 6: Tension straightening: After the profile is ejected from the mold, a traction machine is used to give the profile a certain traction tension, and at the same time, it moves synchronously with the profile outflow speed, so that the profile can eliminate longitudinal shape irregularities, reduce its residual stress, improve its strength characteristics and maintain its good surface.

[0012] Step 7: Artificial aging: The aging temperature is 200℃, and the aging insulation time is 1-2 hours. The aging treatment should be uniform in temperature, and the temperature difference should not exceed ±3-5℃.

[0013] Preferably, the length of the ingot is determined by the volume method, Vo=V1+Vn, AoLo=A1·L1+A·Ln, Lo / Ko=L1 / λ+Ln, Lo=(L1 / λ+Ln)·K, where: Vo is the volume of the ingot (mm3), V1 is the volume of the profile (mm3), Vn is the residual volume (mm3); Ao is the area of ​​the ingot (mm2), Lo is the length of the ingot (mm), A1 is the cross-sectional area of ​​the profile (mm2), L1 is the length of the profile (mm), A is the area of ​​the extrusion barrel (mm2); Ln is the residual length (mm), K=A / Ao filling coefficient, λ=A / A1 extrusion coefficient.

[0014] Preferably, in step seven, an aging temperature of 180-190° C. and an aging holding time of 3-4 hours can be used to improve mechanical properties, while production efficiency will be reduced.

[0015] Preferably, the ingot mould is a mould for forming rods, plates, tubes, wires or blocks.

[0016] Preferably, the preheating temperature of the extrusion die is 400°C-480°C.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention controls the total amount of Mg2Si to 0.79% and the content of silicon to improve the tensile strength and yield strength of the aluminum alloy. The extrusion speed can be increased by homogenizing annealing of the aluminum alloy. Compared with the ingot without homogenizing annealing, the extrusion pressure can be reduced by about 6%-10%. A closed-loop system is formed by adjusting and controlling the extrusion temperature, extrusion speed and extrusion pressure during the extrusion process to maximize the extrusion speed and production efficiency while ensuring the best performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 is a process flow chart of the preparation method of the present invention;

[0021] Figure 2 TEM image of the nano-scale precipitation strengthening phase of the extruded structure of the present invention;

[0022] Figure 3 It is the low-magnification microscopic and high-magnification microscopic organization diagram of the present invention; DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] See also Figure 1-3The present invention provides the following technical solutions: a high-performance low-carbon recycled aluminum extrusion profile and a preparation method thereof, wherein the total amount of Mg2Si is controlled at 0.79%, and when the silicon excess is 0.1%, the mechanical property σb of the alloy is about 218Mpa, which has greatly exceeded the national standard performance, and when the excess silicon is increased from 0.1% to 0.13%, σb can be increased to 250Mpa, that is, an increase of 14.6%. To form a certain amount of Mg2Si, the silicon loss caused by the impurity content such as Fe and Mn must first be considered, that is, a certain amount of excess silicon must be guaranteed. In order to make the magnesium in the alloy fully match the silicon, in actual batching, Mg:Si<1.73 must be consciously made, and the chemical composition mass percentage is: Mg: 0.65%-0.85%; Si: 0.35%-0.50%; Mg:Si=1.3-2.4; the impurity Fe is controlled to be <0.10%-0.25%; Mn<0.10%.

[0026] Specifically, a method for preparing a high-performance low-carbon recycled aluminum extruded profile comprises the following steps:

[0027] Step 1: Alloy smelting: Raise the furnace temperature to not less than 700°C, put recycled aluminum, intermediate alloy containing required elements and a small amount of pure aluminum into the furnace in batches for melting, and after complete melting, refine and degasify to obtain a primary aluminum melt.

[0028] Step 2: Alloy refining: Sampling and analyzing the aluminum melt, adding metal elements or intermediate alloys to adjust the aluminum melt to the target composition of the aluminum alloy, and after refining and degassing, obtaining a refined alloy melt with the desired target composition.

[0029] Step 3: Ingot casting: The refined melt obtained in step 2 is used to prepare an aluminum alloy ingot of target composition by a semi-continuous casting method.

[0030] Step 4: Homogenizing annealing of ingot: Homogenizing annealing is carried out at a temperature of 560+20°C, and the temperature is kept for 4-6 hours. The cooling method is forced air cooling or water spraying rapid cooling.

[0031] Step 5: Extrusion and shaping: Heat the ingot at a temperature of 430-480°C, preheat the extrusion die, and extrude at a speed of 20-100 m / min. At the same time, in order to prevent extrusion cracks, the extrusion speed should be gradually reduced as the extrusion process proceeds and the temperature of the deformation zone increases.

[0032] Step 6: Tension straightening: After the profile is ejected from the mold, a traction machine is used to give the profile a certain traction tension, and at the same time, it moves synchronously with the profile outflow speed, so that the profile can eliminate longitudinal shape irregularities, reduce its residual stress, improve its strength characteristics and maintain its good surface.

[0033] Step 7: Artificial aging: The aging temperature is 200℃, and the aging insulation time is 1-2 hours. The aging treatment should be uniform in temperature, and the temperature difference should not exceed ±3-5℃.

[0034] Specifically, the length of the ingot is determined by the volume method, Vo=V1+Vn, AoLo=A1·L1+A·Ln, Lo / Ko=L1 / λ+Ln, Lo=(L1 / λ+Ln)·K, where: Vo is the volume of the ingot (mm3), V1 is the volume of the profile (mm3), Vn is the residual volume (mm3); Ao is the area of ​​the ingot (mm2), Lo is the length of the ingot (mm), A1 is the cross-sectional area of ​​the profile (mm2), L1 is the length of the profile (mm), A is the area of ​​the extrusion barrel (mm2); Ln is the residual length (mm), K=A / Ao filling coefficient, λ=A / A1 extrusion coefficient.

[0035] Specifically, in step seven, an aging temperature of 180-190° C. and an aging holding time of 3-4 hours can be used to improve mechanical properties, while production efficiency will be reduced.

[0036] In particular, an ingot mould is a mould for forming rods, plates, tubes, wires or blocks.

[0037] Specifically, the preheating temperature of the extrusion die is 400°C-480°C.

[0038] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-performance low-carbon recycled aluminum extrusion profile, characterized by: The total amount of Mg2Si is controlled at 0.79%, and the mechanical property σb of the alloy is about 218Mpa when the excess silicon is 0.1%. When the excess silicon is increased from 0.1% to 0.13%, σb can be increased to 250Mpa, that is, an increase of 14.6%. To form a certain amount of Mg2Si, the silicon loss caused by the impurity content such as Fe and Mn must be considered first, that is, a certain amount of excess silicon must be guaranteed. In order to make the magnesium in the alloy fully match the silicon, the actual ingredients must be consciously made Mg:Si<1.

73. The chemical composition mass percentage is: Mg: 0.65%-0.85%; Si: 0.35%-0.50%; Mg:Si=1.3-2.4; impurity Fe is controlled at <0.10%-0.25%; Mn <0.10%.

2. The method for preparing a high-performance low-carbon recycled aluminum extrusion profile according to claim 1, characterized in that: The following steps are involved: Step 1: Alloy smelting: Raise the furnace temperature to not less than 700°C, put recycled aluminum, intermediate alloy containing required elements and a small amount of pure aluminum into the furnace in batches for melting, and after complete melting, refine and degasify to obtain a primary aluminum melt. Step 2: Alloy refining: Sampling and analyzing the aluminum melt, adding metal elements or intermediate alloys to adjust the aluminum melt to the target composition of the aluminum alloy, and after refining and degassing, obtaining a refined alloy melt with the desired target composition. Step 3: Ingot casting: The refined melt obtained in step 2 is used to prepare an aluminum alloy ingot of target composition by a semi-continuous casting method. Step 4: Homogenizing annealing of ingot: Homogenizing annealing is carried out at a temperature of 560+20°C, and the temperature is kept for 4-6 hours. The cooling method is forced air cooling or water spraying rapid cooling. Step 5: Extrusion and shaping: Heat the ingot at a temperature of 430-480°C, preheat the extrusion die, and extrude at a speed of 20-100 m / min. At the same time, in order to prevent extrusion cracks, the extrusion speed should be gradually reduced as the extrusion process proceeds and the temperature of the deformation zone increases. Step 6: Tension straightening: After the profile is ejected from the mold, a traction machine is used to give the profile a certain traction tension, and at the same time, it moves synchronously with the profile outflow speed, so that the profile can eliminate longitudinal shape irregularities, reduce its residual stress, improve its strength characteristics and maintain its good surface. Step 7: Artificial aging: The aging temperature is 200℃, and the aging insulation time is 1-2 hours. The aging treatment should be uniform in temperature, and the temperature difference should not exceed ±3-5℃.

3. The method for preparing a high-performance low-carbon recycled aluminum extrusion profile according to claim 2, characterized in that: The length of the ingot is determined by the volume method, Vo=V1+Vn, AoLo=A1·L1+A·Ln, Lo / Ko=L1 / λ+Ln, Lo=(L1 / λ+Ln)·K, where: Vo-ingot volume (mm3), V1-profile volume (mm3), Vn-residual volume (mm3); Ao-ingot area (mm2), Lo-ingot length (mm), A1-profile cross-sectional area (mm2), L1-profile length (mm), A-extrusion barrel area (mm2); Ln-residual length (mm), K=A / Ao filling coefficient, λ=A / A1 extrusion coefficient.

4. The method for preparing a high-performance low-carbon recycled aluminum extrusion profile according to claim 2, characterized in that: In step seven, an aging temperature of 180-190°C and an aging holding time of 3-4 hours can be used to improve the mechanical properties, while the production efficiency will be reduced.

5. The method for preparing a high-performance low-carbon recycled aluminum extrusion profile according to claim 2, characterized in that: Ingot moulds are moulds used to form rods, plates, tubes, wire or blocks.

6. The method for preparing a high-performance low-carbon recycled aluminum extrusion profile according to claim 2, characterized in that: The preheating temperature of the extrusion die is 400℃-480℃.

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