CN115261649A - High-performance low-carbon secondary aluminum extruded section and preparation method thereof - Google Patents

Abstract

The invention discloses a high-performance low-carbon secondary aluminum extruded section and a preparation method thereof, and relates to the technical field of aluminum alloy. The alloy comprises the following chemical components in percentage by mass: 0.55 to 0.85 percent of Si, 0.5 to 0.75 percent of Mg, 0.1 to 0.5 percent of Cu, 0.13 to 0.4 percent of Fe0.1 to 0.2 percent of Cr, 0.2 to 0.55 percent of Mn, less than or equal to 0.1 percent of Ti, less than or equal to 0.2 percent of Zn, 0.05 to 0.15 percent of the total content of Mo, V and Zr, and the balance of Al and inevitable impurities. The component alloy is subjected to alloy smelting, alloy refining, bar casting and homogenization treatment, then extrusion processing is carried out, and the extruded aluminum profile can be directly used or used after aging treatment. The tensile yield strength of the extruded aluminum profile alloy in the extrusion direction is not lower than 280MPa; bending test of the alloy in the vertical extrusion direction can obtain an equivalent bending angle of 2.0mm not less than 80 degrees.

Description

A high-performance low-carbon recycled aluminum extrusion profile and its preparation method

technical field

The invention relates to the technical field of recycled aluminum alloy extrusion profiles, in particular to a high-performance low-carbon recycled aluminum extrusion profile and a preparation method thereof.

Background technique

At present, all countries are vigorously developing and promoting new energy vehicles and photovoltaic power generation equipment. Taking new energy vehicles as an example, the production and sales have increased rapidly in recent years, and the overall strength has been significantly improved, which has strongly promoted the reduction of carbon emissions during the use of vehicles. 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 automotive products. However, structural parts have strict requirements on material performance, and electrolytic aluminum must be used for smelting And subsequent processing, resulting in high carbon emissions in the procurement of parts and vehicle raw materials, revealing prominent problems that are contrary to the overall goal of energy conservation and emission reduction. It is urgent to promote the low-carbon development of aluminum materials and automotive products through technological innovation.

The output and consumption of aluminum and its alloys rank first among non-ferrous metals, second only to steel, and are widely used in automobiles, ships, aerospace and other fields. The disadvantages of electrolytic production of primary aluminum are high energy consumption and large environmental pollution. Compared with primary aluminum, the energy consumption for producing 1.0 ton of recycled aluminum is only 5.0% of that of primary aluminum, which is equivalent to saving 3443kg of standard coal, saving 22m ³ of water, and reducing solid waste discharge by 20 tons. Up to now, automobiles including Daimler, Volkswagen, BMW, Volvo, and Nissan have successively announced their respective "carbon reduction" goals. The application of recycled aluminum materials is one of the important ways to achieve their "carbon reduction" goals.

The key technology for preparing high-quality recycled aluminum is to control the relatively high content of iron in recycled aluminum, and the content of iron impurities is directly proportional to the use ratio of scrap aluminum. Iron impurities generally exist in the form of coarse needle-shaped brittle intermetallic compounds in aluminum alloys, which seriously affect the properties of aluminum alloys. At the same time, it increases the risk of surface cracking of the cast rod during high-speed extrusion, which limits the extrusion speed and the difficulty of forming complex extrusion sections.

CN 114231800 A discloses a high-performance low-carbon aluminum alloy and its preparation method. The chemical composition of the alloy is calculated by mass percentage: Si: 6.0-8.0%, Cu: 3.0-5.0%, Mg: 0.2-0.6%, Fe≤0.8 %, Mn: 0.3-0.6%, Ti: 0.02-0.04%, La: 0.05-0.15%, and the balance is Al and unavoidable impurities. The alloy is modified using La. The yield strength of the final casting reaches more than 400MPa, the tensile strength reaches more than 430MPa, and the elongation reaches more than 4%. However, the addition of rare earth element lanthanum makes the overall cost of the alloy higher, and the strength and plasticity of the alloy are lower.

CN 112280985 A discloses a method for manufacturing high-strength and tough aluminum alloys by using recycled aluminum. The chemical composition of the alloy is calculated by mass percentage: Mg 0.1-0.9%, Si 7.0-11.5%, Mn≤0.85%, Ti≤0.25%, Zr ≤0.25%, Cr≤0.25%, V≤0.25%, Sc≤0.25%, Cu≤0.15%, Fe≤0.15%, Sr≤0.06%, individual content of other elements ≤0.05%, total content of other elements ≤0.15%. Alloy uses old wheels as its main raw material, ignoring cans, another major source of recycled aluminum. In the alloy system of the invention, the tolerance to iron is relatively weak, only 0.15%.

CN 114231771 A discloses a high-performance aluminum alloy prepared by utilizing recycled aluminum and its preparation method. The prepared high-performance aluminum alloy contains, by weight percentage, 1.5-2.0% of magnesium, 1.5-2.0% of copper, and 0.08-1.2% of silicon %, manganese 0.2-0.3%, iron 0.5-1.5%, titanium 0.02-0.04%, molybdenum 0.05-0.08%, tungsten 0.03-0.05%, calcium 0.01-0.02%, and the balance is aluminum and unavoidable impurities. The alloy uses discarded pop-top cans as the main production raw material, resulting in a high content of Fe in the alloy. This patent document adopts a method of increasing iron removal process steps to reduce the iron content, which increases the difficulty of the process and increases the production cost.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high-performance low-carbon recycled aluminum extrusion profile and its preparation method, which overcomes the shortcomings of the existing technology and can use a higher proportion of different types of recycled aluminum for the production of recycled aluminum extrusion profiles , improve the mechanical properties of the alloy, and can meet the performance requirements for the manufacture and application of structural parts of new energy vehicles.

In order to solve the above technical problems, the present invention provides the following technical solutions:

A high-performance low-carbon recycled aluminum extrusion profile, in terms of mass percentage, the casting composition includes: Si 0.55-0.85%, Mg 0.5-0.75%, Cu 0.1-0.5%, Fe 0.2-0.4%, Cr 0.1-0.2% , Mn 0.2～0.55%, Ti≤0.1%, Zn≤0.2%, the total content of Mo, V and Zr is between 0.05～0.15%, the rest is Al and unavoidable impurities, and the content of each impurity element is not More than 0.05%, and the total amount of impurities is not more than 0.15%.

Preferably, in terms of mass percentage, the casting composition includes: Si 0.6-0.75%, Mg 0.5-0.65%, Cu 0.1-0.3%, Fe 0.2-0.4%, Cr 0.1-0.2%, Mn 0.4-0.55%, Ti≤ 0.1%, Zn≤0.1%, the total content of Mo, V and Zr is between 0.05% and 0.15%, and the rest is Al and inevitable impurities. The content of each impurity element is not more than 0.05%, and the total amount of impurities is not more than 0.1%. More than 0.15%, the proportion of recycled aluminum used in raw materials is not less than 70%.

Preferably, the high-performance low-carbon recycled aluminum extruded profile is composed of a partially recrystallized structure and contains a large amount of dispersed fibrous intermetallic compounds.

Preferably, the intermetallic compound mainly consists of two granular precipitated phases: one is AlMnCrFeSi phase; the other is AlMSi phase, and M is at least one element among Fe, Mo, V and Zr.

The second aspect provides a method for preparing high-performance low-carbon recycled aluminum extrusion profiles, including:

Step 1: alloy melting. Raise the temperature of the furnace to not lower than 700°C, put the recycled aluminum, the intermediate alloy containing the required elements and a small amount of pure aluminum into the furnace for melting in batches, and after the melting is complete, after refining and degassing, primary smelted aluminum is obtained 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, refining and degassing, and obtaining the refined alloy melt of the required target composition;

Step 3: Bar casting. For the refining solution obtained in step 2, the aluminum alloy bar of the target composition is prepared by a semi-continuous casting method;

Step 4: Homogenization. Carrying out one-step homogenization or two-step homogenization treatment on the semi-continuous casting rod obtained in step 3, the homogenization treatment temperature is 500-580°C;

Step 5: Extrusion. Extruding the homogenized bar obtained in step 4, the extrusion preheating temperature of the alloy is not lower than 480°C, and the extrusion outlet temperature is between 530°C and 560°C;

Step six: aging treatment. Perform aging treatment on the extruded profile in Step 5, the aging temperature is between 120-195° C., and the aging time is 2.0-10.0 h.

Preferably, step 1 and step 2 use a mass percentage of recycled aluminum ≥ 70%, wherein the mass percentage of 6xxx series scrap aluminum is ≥ 20%, and the mass percentage of pop can waste aluminum ≥ 30%; step 4 adopts one-step homogenization treatment at a temperature of 530 Insulate at ~550°C for 2.0 to 5.0 hours.

Preferably, Step 4 adopts two-step homogenization treatment, firstly, heat preservation at 500-520°C for 2.0-5.0h, and then heat preservation at 560-580°C for 1.0-2.0h.

Preferably, the extrusion preheating temperature of the alloy in step five is not lower than 500°C, the extrusion outlet temperature is between 540-550°C, the extrusion ratio is ≥15, and the extrusion speed of the pressure head is between 2.0-6.0mm/s between.

Preferably, the aging treatment in Step 6 is a two-step aging heat treatment, the aging temperature is between 150°C and 190°C, and the single-step aging treatment time does not exceed 3.0h.

Preferably, the tensile yield strength of the prepared recycled aluminum extrusion profile in the extrusion direction is not less than 280MPa; the 2mm equivalent bending angle obtained by the bending test of the alloy in the direction perpendicular to the extrusion direction is not less than 80° .

Preferably, the prepared recycled extruded aluminum profile is used for photovoltaic power generation equipment and new energy electric vehicle parts.

Preferably, the prepared recycled extruded aluminum profiles are used for anti-collision beams, door sill beams, floor beams and water tank upper beams of new energy electric vehicles.

The main alloy components of 6xxx series scrap aluminum are Al, Mg and Si.

A small amount of Fe will combine with Al, Mn, Cr, and Si elements during the homogenization process of aluminum alloy to precipitate nano-scale fine and dispersed AlMnCrFeSi disperse phase particles, which will pin the moving dislocations and sub-phase particles in the subsequent extrusion molding process. Grain boundaries inhibit the formation of fully recrystallized structures. With the increase of Fe content, the nano-scale dispersed phase particles will continue to grow into micron-scale coarse acicular brittle iron-rich phases. Coarse acicular iron-rich phases not only adversely affect the mechanical properties of the alloy, but also consume the Si element in the alloy system, reduce the number of Mg ₂ Si reinforcements in the alloy system, and weaken the solid solution aging of Mg ₂ Si particles. Enhanced effect. The inventors found that adding a small amount of Mo, V and Zr to the alloy system can not only transform the coarse acicular iron-rich phase into short rods and fine particles, but also form new AlMSi dispersed phase particles (M is At least one element among Fe, Mo, V and Zr), plays the role of precipitation strengthening, makes up for the loss of mechanical properties caused by the increase of Fe content, and makes the alloy have good tensile properties.

In addition, the inventors also found that when the composition range of Mn is 0.45-0.55%, and the composition range of Cr is 0.1-0.15%, adding a certain amount of Mo, V and Zr to the alloy can make the microstructure after extrusion Shows a partially recrystallized form. There are a large number of subgrain boundaries and dislocations induced by extrusion deformation in the unrecrystallized grains. A large number of dislocations can accelerate the diffusion rate of Mo, Zr and V, so that the atoms of these three elements dissolved in the aluminum matrix accelerate the diffusion to the formed subgrain boundary during the extrusion process, reducing the energy of the subgrain boundary, Improve the fracture resistance of the subgrain boundary, thereby improving the bending performance of the material. It has been verified by experiments that when the addition ratio of Mo, V and Zr is controlled below 0.05%, the content of atoms dissolved in the aluminum matrix during homogenization heat treatment is low. When the addition ratio of Mo, V and Zr exceeds 0.15%, these three elements tend to combine with aluminum atoms to form coarse intermetallic compounds, and will not increase the proportion of atoms dissolved in the aluminum matrix. In summary, when the addition ratio of Mo, V and Zr is controlled in the range of 0.05-0.15%, the bending performance of the alloy material is the best.

Besides, the two-step homogenization treatment is essential to increase the solid solubility of Mo, V and Zr in the Al matrix. After one-step homogenization treatment at 500-520°C to dissolve the low-melting point eutectic product, it is beneficial to increase the temperature to 560-580°C in the second step of homogenization treatment, which can ensure sufficient Mo, V and Zr atoms are dissolved into the aluminum matrix. Preheat the alloy before extrusion processing, the preheating temperature is not lower than 500°C, the extrusion outlet temperature is between 530-560°C, the extrusion ratio is ≥15, and the extrusion speed of the pressure head is between 2.0-6.0mm/s between. Under the extrusion process parameters, the size of the iron-rich phase in the product is smaller, the shape is more rounded, and the distribution of various dispersion strengthening phases is also the most uniform, which can significantly improve the material without losing tensile properties. bending performance.

The present invention compares with prior art, the beneficial effect of above-mentioned technical scheme of the present invention is as follows:

1. The preparation method of recycled aluminum extruded profiles provided by the invention conforms to the development concept of green environmental protection, energy saving and emission reduction, and alleviates the problem of shortage of domestic aluminum ore resources while reducing production costs.

2. The alloy composition system provided by the invention has a better tolerance to the impurity element Fe, allowing the use of higher proportions of different types of recycled scrap aluminum as raw materials for production.

3. The recycled aluminum extrusion profile prepared by the invention not only has good tensile properties, but also has excellent bending resistance, and can be used for the production and processing of typical parts of new energy vehicles.

Description of drawings

Fig. 1 shows the process flow diagram of the method for preparing recycled aluminum extruded profiles according to the present invention;

Fig. 2 shows the time and temperature change curve diagram of the production process of secondary aluminum extrusion type according to the present invention;

Fig. 3 shows example 1 recycled aluminum extruded profile SEM microstructure figure;

Fig. 4 shows example 2 recycled aluminum extruded profiles SEM microstructure figure;

FIG. 5 shows the engineering stress-strain curves of Example 1 and Example 2.

Detailed ways

The high-performance low-carbon recycled aluminum extrusion profile prepared by the present invention uses recycled 6xxx series waste aluminum and recycled pop cans as main raw materials, and the main alloy components of 6xxx series waste aluminum are Al, Mg, and Si. The high-performance low-carbon recycled aluminum extrusion profile is prepared. The method is: put the recovered 6xxx series waste aluminum and recycled pop cans into the melting furnace, raise the temperature of the melting furnace to not lower than 700°C, and after the recovered aluminum is completely melted, after refining and degassing, the primary smelting melt is obtained; The aluminum melt is sampled and analyzed, and the amount of elements that need to be added is calculated according to the composition formula of the target aluminum alloy, and then the metal elements that need to be added are added to the aluminum melt, and the refined melt is obtained after secondary refining and degassing; The aluminum alloy casting rod with the target composition is prepared by the continuous casting method; the obtained semi-continuous casting rod is subjected to homogenization treatment; the obtained homogenized rod is subjected to extrusion processing, and the extrusion preheating temperature of the alloy is above 480°C , the extrusion outlet temperature is between 530-560°C, the extrusion ratio is ≥15, and the extrusion speed of the pressure head is between 2.0-6.0mm/s; the extruded product can be subjected to one-step or multi-step aging heat treatment according to requirements , and the aging temperature is between 120 and 195°C.

The technical solutions in the embodiments of the present invention will be clearly and completely described below.

Example 1

A high-performance low-carbon recycled aluminum extrusion profile, the mass percentages of its chemical components are: Si 0.55%, Mg0.75%, Cu 0.1%, Fe 0.3%, Cr 0.1%, Mn 0.55%, Ti 0.1%, Zn 0.2%, the total content of Mo, V and Zr is 0.05%, and the rest are Al and unavoidable impurities. The content of each impurity element is not more than 0.05%, and the total amount of impurities is not more than 0.15%. 6xxx series are recovered from raw materials The usage ratio of scrap aluminum and recycled cans is 75%.

The preparation method of above-mentioned alloy follows the steps:

Step 1: alloy melting. Raise the temperature of the furnace to not lower than 700°C, put the recycled aluminum, the intermediate alloy containing the required elements and a small amount of pure aluminum into the furnace for melting in batches, and after the melting is complete, after refining and degassing, primary smelted aluminum is obtained 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, refining and degassing, and obtaining the refined alloy melt of the required target composition;

Step 3: Bar casting. For the refining solution obtained in step 2, the aluminum alloy bar of the target composition is prepared by a semi-continuous casting method;

Step 4: Carry out one-step homogenization heat treatment on the obtained semi-continuous casting bar, the homogenization temperature is 530°C, and the temperature is kept for 5 hours;

Step 5: Extrusion. Extruding the homogenized bar obtained in step 4, the extrusion preheating temperature of the alloy is not lower than 480°C, the extrusion outlet temperature is 530°C, and the extrusion speed of the pressure head is 6.0mm/s;

Step six: aging treatment. Perform aging treatment on the extruded profile in Step 5, the aging temperature is 120° C., and the aging time is 10.0 h.

The mechanical properties of the obtained aluminum alloy were tested, wherein the tensile properties were tested on a universal tensile testing machine at room temperature, and the tensile results were averaged from 3-5 samples; the bending properties were tested according to the VDA238-100 standard.

Example 2

A high-performance low-carbon recycled aluminum extrusion profile, the mass percentages of its chemical components are: Si 0.85%, Mg0.5%, Cu 0.5%, Fe 0.13%, Cr 0.2%, Mn 0.2%, Ti 0.05%, Zn 0.1%, the total content of Mo, V and Zr is 0.15%, and the rest are Al and unavoidable impurities. The content of each impurity element does not exceed 0.05%, and the total amount of impurities does not exceed 0.15%. 6xxx series are recovered from raw materials The usage ratio of scrap aluminum and recycled cans is 81%.

The preparation steps of embodiment 2 are consistent with embodiment 1, difference is:

Step 4: Carry out one-step homogenization heat treatment on the obtained semi-continuous casting bar, the homogenization temperature is 550°C, and the temperature is kept for 2.0h;

Step 5: Extrusion. Extruding the homogenized rod obtained in step 4, the extrusion outlet temperature is 560°C, and the extrusion speed of the pressure head is 2.0mm/s;

Step six: aging treatment. Perform aging treatment on the extruded profile in Step 5, the aging temperature is 195° C., and the aging time is 2.0 h.

Example 3

A high-performance low-carbon recycled aluminum extrusion profile, the mass percentage of each chemical composition is: Si 0.7%, Mg0.63%, Cu 0.3%, Fe 0.4%, Cr 0.15%, Mn 0.38%, Ti 0.03%, Zn 0.15%, the total content of Mo, V and Zr is 0.1%, and the rest is Al and unavoidable impurities. The content of each impurity element does not exceed 0.05%, and the total amount of impurities does not exceed 0.15%. 6xxx series are recovered from raw materials The usage ratio of scrap aluminum and recycled cans is 77%.

The preparation steps of embodiment 3 are consistent with embodiment 1, difference is:

Step 4: Carry out one-step homogenization heat treatment on the obtained semi-continuous casting bar, the homogenization temperature is 540°C, and the temperature is kept for 3.5h;

Step 5: Extrusion. Extruding the homogenized rod obtained in step 4, the extrusion outlet temperature is 545°C, and the extrusion speed of the pressure head is 4.0mm/s;

Step six: aging treatment. Perform aging treatment on the extruded profile in Step 5, the aging temperature is 158° C., and the aging time is 6.0 h.

Example 4

A high-performance low-carbon recycled aluminum extrusion profile, the mass percentage of each chemical composition is: Si 0.55%, Mg0.75%, Cu 0.1%, Fe 0.2%, Cr 0.1%, Mn 0.55%, Ti 0.08%, Zn 0.16%, the total content of Mo, V and Zr is 0.05%, and the rest are Al and unavoidable impurities. The content of each impurity element does not exceed 0.05%, and the total amount of impurities does not exceed 0.15%. 6xxx series are recovered from raw materials The usage ratio of scrap aluminum and recycled cans is 74%.

The preparation step of embodiment 4 is consistent with embodiment 1, difference is:

Step 4: Carry out one-step homogenization heat treatment on the obtained semi-continuous casting bar, the homogenization temperature is 535°C, and the temperature is kept for 3.0h;

Step 5: Extrusion. Extruding the homogenized rod obtained in step 4, the extrusion outlet temperature is 554°C, and the extrusion speed of the pressure head is 3.0mm/s;

Step six: aging treatment. Perform aging treatment on the extruded profile in Step 5, the aging temperature is 165° C., and the aging time is 6.0 h.

Example 5

A high-performance low-carbon recycled aluminum extrusion profile, the mass percentages of its chemical components are: Si 0.81%, Mg0.61%, Cu 0.29%, Fe 0.24%, Cr 0.11%, Mn 0.4%, Ti 0.06%, Zn 0.05%, the total content of Mo, V and Zr is 0.13%, and the rest are Al and unavoidable impurities. The content of each impurity element does not exceed 0.05%, and the total amount of impurities does not exceed 0.15%. 6xxx series are recovered from raw materials The usage ratio of scrap aluminum and recycled cans is 73%.

The preparation step of embodiment 5 is consistent with embodiment 1, difference is:

Step 4: Carry out one-step homogenization heat treatment on the obtained semi-continuous casting rod, the homogenization temperature is 545°C, and the temperature is kept for 4.0h;

Step 5: Extrusion. Extruding the homogenized rod obtained in step 4, the extrusion outlet temperature is 557°C, and the extrusion speed of the pressure head is 5.0mm/s;

Step six: aging treatment. Perform aging treatment on the extruded profile in step 5, the aging temperature is 174° C., and the aging time is 4.0 h.

Example 6

A high-performance low-carbon recycled aluminum extrusion profile, the mass percentage of each chemical composition is: Si 0.71%, Mg0.65%, Cu 0.4%, Fe 0.32%, Cr 0.16%, Mn 0.41%, Ti 0.07%, Zn 0.07%, the total content of Mo, V and Zr is 0.14%, and the rest is Al and unavoidable impurities. The content of each impurity element does not exceed 0.05%, and the total amount of impurities does not exceed 0.15%. 6xxx series are recovered from raw materials The usage ratio of scrap aluminum and recycled cans is 70%.

The preparation step of embodiment 6 is consistent with embodiment 1, difference is:

Step 4: Carry out two-step homogenization heat treatment on the obtained semi-continuously cast rod, the first step of homogenization temperature is 500°C, heat preservation for 5.0h, and the second step homogenization temperature is 580°C, heat preservation for 1.0h;

Step 5: Extrusion. Extruding the homogenized rod obtained in step 4, the extrusion outlet temperature is 532°C, and the extrusion speed of the pressure head is 2.0mm/s;

Step six: aging treatment. Perform aging treatment on the extruded profile in Step 5, the aging temperature is 127° C., and the aging time is 2.0 h.

Example 7

A high-performance low-carbon recycled aluminum extrusion profile, the mass percentage of each chemical composition is: Si 0.75%, Mg0.72%, Cu 0.28%, Fe 0.26%, Cr 0.1%, Mn 0.25%, Ti 0.01%, Zn 0.11%, the total content of Mo, V and Zr is 0.1%, and the rest is Al and unavoidable impurities. The content of each impurity element does not exceed 0.05%, and the total amount of impurities does not exceed 0.15%. 6xxx series are recovered from raw materials The usage ratio of scrap aluminum and recycled cans is 83%.

The preparation steps of embodiment 7 are consistent with embodiment 1, difference is:

Step 4: Carry out two-step homogenization heat treatment on the obtained semi-continuously cast rod, the first-step homogenization temperature is 520°C, heat preservation for 2.0h, and the second-step homogenization temperature is 560°C, heat preservation for 2.0h;

Step 5: Extrusion. Extruding the homogenized rod obtained in step 4, the extrusion outlet temperature is 533°C, and the extrusion speed of the pressure head is 3.0mm/s;

Step six: aging treatment. Perform aging treatment on the extruded profile in Step 5, the aging temperature is 189° C., and the aging time is 10.0 h.

Example 8

A high-performance low-carbon recycled aluminum extrusion profile, the mass percentages of its chemical components are: Si 0.69%, Mg0.67%, Cu 0.48%, Fe 0.39%, Cr 0.19%, Mn 0.44%, Ti 0.04%, Zn 0.14%, the total content of Mo, V and Zr is 0.08%, and the rest are Al and unavoidable impurities. The content of each impurity element does not exceed 0.05%, and the total amount of impurities does not exceed 0.15%. 6xxx series are recovered from raw materials The usage ratio of scrap aluminum and recycled cans is 73%.

The preparation step of embodiment 8 is consistent with embodiment 1, difference is:

Step 4: Carry out two-step homogenization heat treatment on the obtained semi-continuously cast rods, the first-step homogenization temperature is 510°C, heat preservation for 3.5h, and the second-step homogenization temperature is 570°C, heat preservation for 1.5h;

Step 5: Extrusion. Extruding the homogenized rod obtained in step 4, the extrusion outlet temperature is 541°C, and the extrusion speed of the pressure head is 4.0mm/s;

Step six: aging treatment. Perform aging treatment on the extruded profile in Step 5, the aging temperature is 176° C., and the aging time is 8.0 h.

Example 9

A high-performance low-carbon recycled aluminum extrusion profile, the mass percentage of each chemical composition is: Si 0.63%, Mg0.55%, Cu 0.24%, Fe 0.21%, Cr 0.14%, Mn 0.35%, Ti 0.02%, Zn 0.09%, the total content of Mo, V and Zr is 0.07%, and the rest is Al and unavoidable impurities. The content of each impurity element does not exceed 0.05%, and the total amount of impurities does not exceed 0.15%. 6xxx series are recovered from raw materials The usage ratio of scrap aluminum and recycled cans is 84%.

The preparation step of embodiment 9 is consistent with embodiment 1, difference is:

Step 4: Carry out two-step homogenization heat treatment on the obtained semi-continuously cast rod, the first-step homogenization temperature is 505°C, heat preservation for 4.0h, and the second-step homogenization temperature is 575°C, heat preservation for 1.25h;

Step 5: Extrusion. Extruding the homogenized rod obtained in step 4, the extrusion outlet temperature is 555°C, and the extrusion speed of the pressure head is 6.0mm/s;

Step six: aging treatment. Perform aging treatment on the extruded profile in Step 5, the aging temperature is 154° C., and the aging time is 3.0 h.

Example 10

A high-performance low-carbon recycled aluminum extrusion profile, the mass percentages of its chemical components are: Si 0.56%, Mg0.63%, Cu 0.21%, Fe 0.30%, Cr 0.15%, Mn 0.27%, Ti 0.05%, Zn 0.13%, the total content of Mo, V and Zr is 0.11%, and the rest are Al and unavoidable impurities. The content of each impurity element does not exceed 0.05%, and the total amount of impurities does not exceed 0.15%. 6xxx series are recovered from raw materials The usage ratio of scrap aluminum and recycled cans is 73%.

The preparation step of embodiment 10 is consistent with embodiment 1, difference is:

Step 4: Carry out two-step homogenization heat treatment on the obtained semi-continuously cast rod, the first-step homogenization temperature is 515°C, heat preservation for 3.0h, and the second-step homogenization temperature is 565°C, heat preservation for 1.75h;

Step 5: Extrusion. Extruding the homogenized rod obtained in step 4, the extrusion outlet temperature is 552°C, and the extrusion speed of the pressure head is 2.0mm/s;

Step six: aging treatment. Perform aging treatment on the extruded profile in Step 5, the aging temperature is 136° C., and the aging time is 7.0 h.

Table 1: Example composition list

Table 2: Example process table

Through the above examples, the applicant found that a small amount of Fe will combine with Al, Mn, Cr, and Si elements during the homogenization process of aluminum alloy to precipitate nano-scale fine and dispersed AlMnCrFeSi dispersed phase particles, which will be nailed in the subsequent extrusion molding process. Tie up moving dislocations and subgrain boundaries, and inhibit the formation of fully recrystallized structures. With the increase of Fe content, the nano-scale dispersed phase particles will continue to grow into micron-scale coarse acicular brittle iron-rich phases. Coarse acicular iron-rich phases not only adversely affect the mechanical properties of the alloy, but also consume the Si element in the alloy system, reduce the number of Mg ₂ Si reinforcements in the alloy system, and weaken the solid solution aging of Mg ₂ Si particles. Enhanced effect. The inventors found that adding a small amount of Mo, V and Zr to the alloy system can not only transform the coarse acicular iron-rich phase into short rods and fine particles, but also form new AlMSi dispersed phase particles (M is At least one element among Fe, Mo, V and Zr), plays the role of precipitation strengthening, makes up for the loss of mechanical properties caused by the increase of Fe content, and makes the alloy have good tensile properties.

In addition, the inventors also found that when the composition range of Mn is 0.45-0.55%, and the composition range of Cr is 0.1-0.15%, adding a certain amount of Mo, V and Zr to the alloy can make the microstructure after extrusion Shows a partially recrystallized form. There are a large number of subgrain boundaries and dislocations induced by extrusion deformation in the unrecrystallized grains. A large number of dislocations can accelerate the diffusion rate of Mo, Zr and V, so that the atoms of these three elements dissolved in the aluminum matrix accelerate the diffusion to the formed subgrain boundary during the extrusion process, reducing the energy of the subgrain boundary, Improve the fracture resistance of the subgrain boundary, thereby improving the bending performance of the material. It has been verified by experiments that when the addition ratio of Mo, V and Zr is controlled below 0.05%, the content of atoms dissolved in the aluminum matrix during homogenization heat treatment is low. When the addition ratio of Mo, V and Zr exceeds 0.15%, these three elements tend to combine with aluminum atoms to form coarse intermetallic compounds, and will not increase the proportion of atoms dissolved in the aluminum matrix. In summary, when the addition ratio of Mo, V and Zr is controlled in the range of 0.05-0.15%, the bending performance of the alloy material is the best.

Besides, the two-step homogenization treatment is essential to increase the solid solubility of Mo, V and Zr in the Al matrix. After one-step homogenization treatment at 500-520°C to dissolve the low-melting point eutectic product, it is beneficial to increase the temperature to 560-580°C in the second step of homogenization treatment, which can ensure sufficient Mo, V and Zr atoms are dissolved into the aluminum matrix. Preheat the alloy before extrusion processing, the preheating temperature is not lower than 500°C, the extrusion outlet temperature is between 530-560°C, the extrusion ratio is ≥15, and the extrusion speed of the pressure head is between 2.0-6.0mm/s between. Under the extrusion process parameters, the size of the iron-rich phase in the product is smaller, the shape is more rounded, and the distribution of various dispersion strengthening phases is also the most uniform, which can significantly improve the material without losing tensile properties. bending performance.

All the above-mentioned embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Claims (12)

1. A high-performance low-carbon recycled aluminum extrusion profile, characterized in that: its chemical composition mass percentage is: Si 0.55-0.85%, Mg 0.5-0.75%, Cu 0.1-0.5%, Fe 0.13-0.4%, Cr 0.1～0.2%, Mn 0.2～0.55%, Ti≤0.1%, Zn≤0.2%, the total content of Mo, V and Zr is between 0.05～0.15%, the rest is Al and unavoidable impurities, each The content of impurity elements does not exceed 0.05%, and the total amount of impurities does not exceed 0.15%. 2. A high-performance low-carbon recycled aluminum extrusion profile according to claim 1, characterized in that its chemical composition mass percentage is: Si 0.6-0.75%, Mg 0.5-0.65%, Cu 0.1-0.3%, Fe 0.2～0.4%, Cr 0.1～0.2%, Mn 0.4～0.55%, Ti≤0.1%, Zn≤0.1%, the total content of Mo, V and Zr is between 0.05～0.15%, and the rest is Al and For unavoidable impurities, the content of each impurity element does not exceed 0.05%, and the total amount of impurities does not exceed 0.15%, and the proportion of recycled aluminum is not less than 70%. 3. A high-performance low-carbon recycled aluminum extruded profile according to claim 1 or 2, characterized in that the extruded aluminum profile is composed of a partially recrystallized structure and contains a large amount of dispersed fibrous intermetallic compounds. 4. A high-performance low-carbon recycled aluminum extrusion profile according to claim 3, characterized in that: the intermetallic compound is mainly two kinds of granular precipitated phases: one is AlMnCrFeSi phase; the other is AlMSi phase, and M is at least one element of Fe, Mo, V and Zr. 5. A high-performance low-carbon recycled aluminum extrusion profile according to any one of claims 1 to 4, characterized in that: the tensile yield strength of the recycled aluminum extrusion profile in the extrusion direction is not less than 280MPa , The 2mm equivalent bending angle obtained by the bending test of the alloy in the vertical extrusion direction is not less than 80°. 6. A method for preparing a high-performance low-carbon recycled aluminum extrusion profile according to any one of claims 1 to 5, characterized in that the preparation method comprises the following steps: Step 1: Alloy smelting, raising the temperature of the furnace to not lower than 700°C, putting recycled aluminum, intermediate alloys containing required elements, and a small amount of pure aluminum into the furnace for melting in batches, and refining and degassing after complete melting After that, the primary smelted aluminum melt is obtained; 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, refining and degassing, and obtaining the refined alloy melt of the required target composition; Step 3: rod casting, for the refined solution obtained in step 2, adopt semi-continuous casting method to prepare aluminum alloy cast rods with the target composition; Step 4: Homogenization treatment, performing one-step homogenization or two-step homogenization treatment on the semi-continuous casting bar obtained in Step 3, and the homogenization treatment temperature is 500-580°C; Step 5: Extrusion forming, extruding the homogenized rod obtained in Step 4, the extrusion preheating temperature of the alloy is not lower than 480°C, and the extrusion outlet temperature is between 530-560°C; Step 6: Aging treatment, performing aging treatment on the extruded profile in step 5, the aging temperature is between 120-195°C, and the aging time is 2.0-10.0h. 7. A method for preparing a high-performance low-carbon recycled aluminum extrusion profile according to claim 6, characterized in that: the mass percentage of recycled aluminum is used in step 1 and step 2 ≥ 70%, and the mass percentage of 6xxx series scrap aluminum is ≥ 20%, and the mass percentage of aluminum cans waste ≥ 30%; Step 4 adopts one-step homogenization heat treatment at a temperature of 530-550° C. for 2.0-5.0 hours. 8. A method for preparing a high-performance low-carbon recycled aluminum extrusion profile according to claim 6 or 7, characterized in that: Step 4 adopts two-step homogenization heat treatment, and first heats at 500-520°C for 2.0-5.0 h, and then keep warm at 560-580°C for 1.0-2.0h. 9. A method for preparing a high-performance low-carbon recycled aluminum extrusion profile according to claim 6 or 7, characterized in that: in step 5, the extrusion preheating temperature of the alloy is not lower than 500°C, and the extrusion exit temperature Between 540 and 550°C, the extrusion ratio is ≥15, and the extrusion speed of the pressure head is between 2.0 and 6.0mm/s. 10. A method for preparing a high-performance low-carbon recycled aluminum extrusion profile according to any one of claims 6-9, characterized in that: the aging treatment in step 6 is a two-step aging heat treatment, and the aging temperature is 150- Between 190°C, the single-step aging treatment time shall not exceed 3.0h. 11. The use of a high-performance low-carbon recycled aluminum extruded profile and its preparation method according to any one of the above claims, characterized in that: the prepared recycled extruded aluminum profile is used for photovoltaic power generation equipment and new energy Electric vehicle components. 12. The use of a high-performance low-carbon recycled aluminum extruded profile and its preparation method according to claim 11, characterized in that: the prepared recycled extruded aluminum profile is used for anti-collision beams of new energy electric vehicles, Threshold beams, floor beams and water tank upper beams and other components.

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