CN115261649A

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

Info

Publication number: CN115261649A
Application number: CN202210782103.2A
Authority: CN
Inventors: 付立铭; 沈耀; 单爱党
Original assignee: Shanghai Jiaotong University
Current assignee: Shanghai Jiaotong University
Priority date: 2022-06-30
Filing date: 2022-06-30
Publication date: 2022-11-01

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

High-performance low-carbon recycled aluminum extruded section and preparation method thereof

Technical Field

The invention relates to the technical field of secondary aluminum alloy extruded sections, in particular to a high-performance low-carbon secondary aluminum extruded section and a preparation method thereof.

Background

At present, new energy automobiles, photovoltaic power generation equipment and the like are vigorously developed and popularized in various countries. Taking a new energy automobile as an example, in recent years, the production and sales volume is rapidly improved, the overall strength is obviously improved, and the reduction of carbon emission in the use stage of the automobile is powerfully promoted. With the rapid development of energy-saving and new energy automobiles, the application of lightweight aluminum alloy structural parts plays an increasingly important role in improving the performance and competitiveness of automobile products, but the structural parts have strict requirements on material performance, and electrolytic aluminum must be adopted for smelting and subsequent processing, so that high carbon emission is caused in the acquisition stage of raw materials of parts and the whole automobile, the outstanding problem of paradox with the overall target of energy conservation and emission reduction is revealed, and the low-carbon development of aluminum materials and automobile products needs to be promoted through technical innovation.

The yield and the dosage of the aluminum and the alloy thereof are first of all located on nonferrous metals, are second to steel, and have wide application in the fields of automobiles, ships, aerospace and the like. The electrolytic method for producing the raw aluminum has the defects of high energy consumption and great environmental pollution. Compared with the original aluminum, the energy consumption for producing 1.0 ton of secondary aluminum is only 5.0 percent of the original aluminum, which is equivalent to saving 3443kg of standard coal and 22m of water³And the solid waste discharge is reduced by 20 tons. Until now, vehicles including those of the Daimler, the public, baoma, walnwo and Nissan have published respective targets of carbon reduction, and the application of the recycled aluminum material is one of the important ways to achieve the target of carbon reduction.

The key technology for preparing high-quality secondary aluminum is to control the inevitable relatively high content of iron element in the recovered aluminum, and the content of iron impurities is in direct proportion to the use proportion of the waste aluminum. Iron impurities generally exist in the form of coarse needle-like brittle intermetallic compounds in the aluminum alloy, and seriously affect various properties of the aluminum alloy. Meanwhile, the risk of surface cracking of the cast rod during high-speed extrusion is increased, and the extrusion speed and the forming difficulty of a complex extrusion section are limited.

CN 114231800A discloses a high-performance low-carbon aluminum alloy and a preparation method thereof, wherein the alloy comprises the following chemical components in percentage by mass: si:6.0 to 8.0%, cu:3.0 to 5.0%, mg: 0.2-0.6%, fe is less than or equal to 0.8%, mn:0.3 to 0.6%, ti:0.02 to 0.04%, la:0.05 to 0.15 percent, and the balance of Al and inevitable impurities. The alloy is modified with 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 the rare earth element lanthanum leads the overall cost of the alloy to be high and the product of strength and elongation of the alloy to be low.

CN 112280985A discloses a method for manufacturing high-strength and high-toughness aluminum alloy by using recovered aluminum, wherein the alloy comprises the following chemical components in percentage by mass: 0.1 to 0.9 percent of Mg, 7.0 to 11.5 percent of Si, less than or equal to 0.85 percent of Mn, less than or equal to 0.25 percent of Ti, less than or equal to 0.25 percent of Zr, less than or equal to 0.25 percent of Cr, less than or equal to 0.25 percent of V, less than or equal to 0.25 percent of Sc, less than or equal to 0.15 percent of Cu, less than or equal to 0.15 percent of Fe, less than or equal to 0.06 percent of Sr, less than or equal to 0.05 percent of single content of other elements and less than or equal to 0.15 percent of total content of other elements. The alloy adopts the old wheel as a main raw material, and omits another main source of the recycled aluminum, namely the pop-top can. In the alloy system of the invention, the iron holding capacity is weak, and is only 0.15%.

CN 114231771A discloses a high-performance aluminum alloy prepared by using recycled aluminum and a preparation method thereof, wherein the prepared high-performance aluminum alloy comprises the following components in percentage by weight: 1.5 to 2.0 percent of magnesium, 1.5 to 2.0 percent of copper, 0.08 to 1.2 percent of silicon, 0.2 to 0.3 percent of manganese, 0.5 to 1.5 percent of iron, 0.02 to 0.04 percent of titanium, 0.05 to 0.08 percent of molybdenum, 0.03 to 0.05 percent of tungsten, 0.01 to 0.02 percent of calcium, and the balance of aluminum and inevitable impurities. The alloy adopts the waste pop-top can as a main production raw material, so that the content of Fe in the alloy is high, the iron content is reduced by adopting a method of increasing iron removal process steps, the process difficulty is increased, and the production cost is increased.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a high-performance low-carbon secondary aluminum extruded section and a preparation method thereof, overcome the defects of the prior art, produce the secondary aluminum extruded section by using different types of recycled aluminum with higher proportion, improve the mechanical property of the alloy, and meet the performance requirements of manufacturing and applying new energy automobile structural members.

In order to solve the technical problems, the invention provides the following technical scheme:

a high-performance low-carbon secondary aluminum extruded section comprises the following 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, 0.2 to 0.4 percent of Fe, 0.1 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, wherein the content of each impurity element is not more than 0.05 percent, and the total content of the impurities is not more than 0.15 percent.

Preferably, the casting composition comprises, in mass percent: 0.6 to 0.75 percent of Si, 0.5 to 0.65 percent of Mg, 0.1 to 0.3 percent of Cu, 0.2 to 0.4 percent of Fe, 0.1 to 0.2 percent of Cr, 0.4 to 0.55 percent of Mn, less than or equal to 0.1 percent of Ti, less than or equal to 0.1 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, wherein the content of each impurity element is not more than 0.05 percent, the total content of the impurities is not more than 0.15 percent, and the use ratio of the recovered aluminum in the raw materials is not less than 70 percent.

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 is mainly two particulate precipitate phases: one is an AlMnCrFeSi phase; the other is an AlMSi phase, and M is at least one element of Fe, mo, V and Zr.

The second aspect provides a preparation method of a high-performance low-carbon secondary aluminum extruded profile, which comprises the following steps:

the method comprises the following steps: and (4) alloy smelting. Raising the temperature of the smelting furnace to be not lower than 700 ℃, putting the recovered aluminum, the intermediate alloy containing the required elements and a small amount of pure aluminum into the furnace in batches for melting, and refining and degassing after the aluminum is completely melted to obtain a primary aluminum melt;

step two: and (5) refining the alloy. Sampling and analyzing the aluminum melt, supplementing metal elements or intermediate alloy, adjusting the aluminum melt to the target component of the aluminum alloy, refining and degassing to obtain a refined alloy melt of the required target component;

step three: and (5) casting the bar. Preparing the aluminum alloy bar with the target component from the refined solution obtained in the step two by adopting a semi-continuous casting method;

step four: and (6) homogenizing. Performing one-step homogenization or two-step homogenization treatment on the semi-continuous casting bar obtained in the step three, wherein the homogenization treatment temperature is 500-580 ℃;

step five: and (4) extrusion molding. Extruding the bar material after the homogenization treatment obtained in the step four, wherein the extrusion preheating temperature of the alloy is not lower than 480 ℃, and the extrusion outlet temperature is between 530 ℃ and 560 ℃;

step six: and (5) aging treatment. And (4) carrying out aging treatment on the extruded section in the step five, wherein the aging temperature is 120-195 ℃, and the aging time is 2.0-10.0 h.

Preferably, the mass percent of the recycled aluminum used in the first step and the second step is more than or equal to 70 percent, wherein the mass percent of the 6xxx series aluminum scrap is more than or equal to 20 percent, and the mass percent of the pop can aluminum scrap is more than or equal to 30 percent; step four, adopting one-step homogenization treatment, and keeping the temperature at 530-550 ℃ for 2.0-5.0 h.

Preferably, the step four adopts two-step homogenization treatment, the temperature is firstly preserved for 2.0 to 5.0 hours at 500 to 520 ℃, and then preserved for 1.0 to 2.0 hours at 560 to 580 ℃.

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

Preferably, the aging treatment of the sixth step is two-step aging heat treatment, the aging temperature is between 150 and 190 ℃, and the single-step aging treatment time is not more than 3.0h.

Preferably, the tensile yield strength of the prepared recycled aluminum extruded profile in the extrusion direction is not lower than 280MPa; bending test of the alloy in the vertical extrusion direction can obtain 2mm equivalent bending angle not less than 80 degrees.

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

Preferably, the prepared regenerated extruded aluminum profile is used for parts such as an anti-collision beam, a threshold beam, a floor cross beam and a water tank upper cross beam of a new energy electric automobile.

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

Trace Fe can be combined with Al, mn, cr and Si elements to precipitate nanoscale fine and dispersed AlMnCrFeSi dispersed-phase particles in the aluminum alloy homogenization treatment process, and moving dislocation and subgrain boundaries are pinned in the subsequent extrusion forming process, so that the formation of a complete recrystallization structure is inhibited. With the increase of Fe content, the nano-scale dispersed phase particles will continue to grow into micron-scale coarse needle-like brittle iron-rich phase. The thick needle-shaped iron-rich phase can not only cause adverse effect on the mechanical property of the alloy, but also consume Si element in the alloy system, thereby reducing Mg in the alloy system₂The amount of Si reinforcement weakens Mg₂The solid solution aging strengthening effect of the Si particles. The inventor finds that adding a small amount of Mo, V and Zr into an alloy system not only can transform a coarse acicular iron-rich phase into a short rod and a fine particle, but also can form new AlMSi dispersed phase particles (M is at least one element of Fe, mo, V and Zr) in the aging treatment process, play a role in precipitation strengthening, compensate the loss of mechanical properties caused by the increase of Fe content, and enable the alloy to have good tensile property.

Furthermore, the inventors have found that when the composition interval of Mn is 0.45 to 0.55% and the composition interval of Cr is 0.1 to 0.15%, the microstructure after extrusion can be made to assume a partially recrystallized morphology by adding a certain amount of Mo, V and Zr to the alloy. Wherein a large amount of subboundaries and dislocations induced by the extrusion deformation exist in unrecrystallized grains. A large amount of dislocation can accelerate the diffusion speed of Mo, zr and V, so that atoms of the three elements which are dissolved in an aluminum matrix are accelerated to diffuse to a formed subboundary in the extrusion process, the energy of the subboundary is reduced, the fracture resistance of the subboundary is improved, and the bending performance of the material is improved. Experiments prove that when the addition ratio of Mo, V and Zr is controlled to be less than 0.05%, the content of atoms dissolved in the aluminum matrix during the 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 do not increase the atomic content ratio dissolved in the aluminum matrix. As described above, the bending properties of the alloy material are best when the addition ratio of Mo, V and Zr is controlled to be in the range of 0.05-0.15%.

In addition to this, a two-step homogenization treatment is essential to increase the solid solubility of Mo, V and Zr in the aluminum matrix. After the low melting point eutectic product is dissolved by the first homogenization treatment at 500-520 ℃, the temperature is advantageously raised to 560-580 ℃ in the second homogenization treatment, which ensures that enough Mo, V and Zr atoms are dissolved in the aluminum matrix. Preheating the alloy before extrusion processing, wherein the preheating temperature is not lower than 500 ℃, the extrusion outlet temperature is between 530 and 560 ℃, the extrusion ratio is not less than 15, and the extrusion speed of a pressure head is between 2.0 and 6.0 mm/s. Under the extrusion process parameters, the obtained iron-rich phase in the product has smaller size, more round appearance and most uniform distribution of various dispersion strengthening phases, and the bending performance of the material can be remarkably improved under the condition of not losing the tensile performance.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

1. the preparation method of the recycled aluminum extruded section provided by the invention conforms to the development concepts of environmental protection, energy conservation and emission reduction, reduces the production cost and simultaneously relieves the problem of shortage of domestic aluminum ore resources.

2. The invention provides an alloy composition system with better inclusion of impurity element Fe, and allows the use of different types of recycled aluminum scraps with higher proportion as production raw materials.

3. The prepared recycled aluminum extruded section has excellent tensile property and bending resistance, and can be used for manufacturing and processing typical parts of new energy automobiles.

Drawings

FIG. 1 shows a process flow diagram of a method for producing a recycled aluminum extruded profile according to the present invention;

FIG. 2 is a graph showing the time versus temperature profile of a recycled aluminum extrusion manufacturing process according to the present invention;

FIG. 3 shows an SEM microstructure of an extruded profile of secondary aluminum of example 1;

FIG. 4 shows an SEM microstructure of an extruded section of secondary aluminum of example 2;

fig. 5 shows the engineering stress-strain curves of examples 1 and 2.

Detailed Description

The high-performance low-carbon regenerated aluminum extruded section prepared by the invention takes the recovered 6xxx series aluminum scrap and the recovered pop-top can as main raw materials, the main alloy components of the 6xxx series aluminum scrap are Al, mg and Si, and the preparation method of the high-performance low-carbon regenerated aluminum extruded section comprises the following steps: putting the recovered 6xxx series aluminum scrap and the recovered pop can into a smelting furnace, raising the temperature of the smelting furnace to be not lower than 700 ℃, and after the recovered aluminum is completely molten, refining and degassing to obtain a primary smelting melt; sampling and analyzing the aluminum melt, calculating the amount of elements to be added according to the component formula of the target aluminum alloy, adding the metal elements to be added into the aluminum melt, and performing secondary refining and degassing to obtain a refined melt; preparing an aluminum alloy cast rod with a target component by adopting a semi-continuous casting method; homogenizing the obtained semi-continuous casting bar; extruding the homogenized bar, wherein the extrusion preheating temperature of the alloy is above 480 ℃, the extrusion outlet temperature is between 530 and 560 ℃, the extrusion ratio is not less than 15, and the extrusion speed of a pressure head is between 2.0 and 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 120-195 ℃.

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

Example 1

A high-performance low-carbon recycled aluminum extruded section comprises the following chemical components in percentage by mass: 0.55% of Si, 0.75% of Mg, 0.1% of Cu, 0.3% of Fe, 0.1% of Cr, 0.55% of Mn, 0.1% of Ti, 0.2% of Zn, 0.05% of the total content of Mo, V and Zr, and the balance of Al and inevitable impurities, wherein the content of each impurity element is not more than 0.05%, the total content of impurities is not more than 0.15%, and the use ratio of the 6xxx series waste aluminum recovered from raw materials to the recovered pop can is 75%.

The preparation method of the alloy comprises the following steps:

step two: and (5) refining the alloy. Sampling and analyzing the aluminum melt, supplementing metal elements or intermediate alloy, adjusting the aluminum melt to the target components of the aluminum alloy, refining and degassing to obtain a refined alloy melt of the required target components;

step four, performing one-step homogenization heat treatment on the obtained semi-continuous casting bar, wherein the homogenization temperature is 530 ℃, and preserving heat for 5 hours;

step five: and (4) extrusion molding. Extruding the bar material after the homogenization treatment obtained in the step four, wherein the extrusion preheating temperature of the alloy is not lower than 480 ℃, the extrusion outlet temperature is 530 ℃, and the extrusion speed of a pressure head is 6.0mm/s;

step six: and (5) aging treatment. And (4) carrying out aging treatment on the extruded section in the fifth step, wherein the aging temperature is 120 ℃, and the aging time is 10.0h.

Testing the mechanical property of the obtained aluminum alloy, wherein the tensile property is carried out on a universal tensile testing machine at room temperature, and the tensile result is the average value of 3-5 samples; the bending properties were tested according to the VDA238-100 standard.

Example 2

A high-performance low-carbon secondary aluminum extruded section comprises the following chemical components in percentage by mass: 0.85% of Si, 0.5% of Mg, 0.5% of Cu, 0.13% of Fe, 0.2% of Cr, 0.2% of Mn, 0.05% of Ti, 0.1% of Zn, 0.15% of the total content of three elements of Mo, V and Zr, and the balance of Al and inevitable impurities, wherein the content of each impurity element is not more than 0.05%, the total content of the impurities is not more than 0.15%, and the use ratio of 6xxx series waste aluminum recovered from raw materials to pop cans recovered is 81%.

The procedure of example 2 is identical to that of example 1, except that:

step four, performing one-step homogenization heat treatment on the obtained semi-continuous casting bar, wherein the homogenization temperature is 550 ℃, and preserving heat for 2.0 hours;

step five: and (4) extrusion forming. Extruding the bar material after the homogenization treatment obtained in the fourth step, wherein the extrusion outlet temperature is 560 ℃, and the extrusion speed of a pressure head is 2.0mm/s;

step six: and (5) aging treatment. And (4) carrying out aging treatment on the extruded section obtained in the fifth step, wherein the aging temperature is 195 ℃, and the aging time is 2.0h.

Example 3

A high-performance low-carbon recycled aluminum extruded section comprises the following chemical components in percentage by mass: 0.7% of Si, 0.63% of Mg, 0.3% of Cu, 0.4% of Fe, 0.15% of Cr, 0.38% of Mn, 0.03% of Ti, 0.15% of Zn, 0.1% of the total content of Mo, V and Zr, and the balance of Al and inevitable impurities, wherein the content of each impurity element is not more than 0.05%, the total content of impurities is not more than 0.15%, and the use ratio of the 6xxx series waste aluminum recovered from raw materials to the recovered pop can is 77%.

The procedure of example 3 is identical to example 1, with the difference that:

step four, performing one-step homogenization heat treatment on the obtained semi-continuous casting bar, wherein the homogenization temperature is 540 ℃, and preserving heat for 3.5 hours;

step five: and (4) extrusion molding. Extruding the bar material after the homogenization treatment obtained in the step four, wherein the temperature of an extrusion outlet is 545 ℃, and the extrusion speed of a pressure head is 4.0mm/s;

step six: and (5) aging treatment. And (4) carrying out aging treatment on the extruded section in the fifth step, wherein the aging temperature is 158 ℃, and the aging time is 6.0h.

Example 4

A high-performance low-carbon secondary aluminum extruded section comprises the following chemical components in percentage by mass: 0.55% of Si, 0.75% of Mg, 0.1% of Cu, 0.2% of Fe, 0.1% of Cr, 0.55% of Mn, 0.08% of Ti, 0.16% of Zn, 0.05% of the total content of Mo, V and Zr, and the balance of Al and inevitable impurities, wherein the content of each impurity element is not more than 0.05%, the total content of impurities is not more than 0.15%, and the use ratio of the 6xxx series waste aluminum recovered from raw materials to the recovered pop can is 74%.

The procedure of example 4 is identical to that of example 1, except that:

step four, performing one-step homogenization heat treatment on the obtained semi-continuous casting bar, wherein the homogenization temperature is 535 ℃, and preserving heat for 3.0 hours;

step five: and (4) extrusion forming. Extruding the bar material after the homogenization treatment obtained in the step four, wherein the temperature of an extrusion outlet is 554 ℃, and the extrusion speed of a pressure head is 3.0mm/s;

step six: and (5) aging treatment. And (4) carrying out aging treatment on the extruded section in the fifth step, wherein the aging temperature is 165 ℃, and the aging time is 6.0h.

Example 5

A high-performance low-carbon secondary aluminum extruded section comprises the following chemical components in percentage by mass: 0.81% of Si, 0.61% of Mg, 0.29% of Cu, 0.24% of Fe, 0.11% of Cr, 0.4% of Mn, 0.06% of Ti, 0.05% of Zn, 0.13% of the total content of Mo, V and Zr, and the balance of Al and inevitable impurities, wherein the content of each impurity element is not more than 0.05%, the total content of impurities is not more than 0.15%, and the use ratio of the 6xxx series waste aluminum in raw materials to the recovered pop can is 73%.

The procedure of example 5 is identical to that of example 1, except that:

step four, performing one-step homogenization heat treatment on the obtained semi-continuous casting bar, wherein the homogenization temperature is 545 ℃, and keeping the temperature for 4.0h;

step five: and (4) extrusion forming. Extruding the bar material after the homogenization treatment obtained in the fourth step, wherein the extrusion outlet temperature is 557 ℃, and the extrusion speed of a pressure head is 5.0mm/s;

step six: and (5) aging treatment. And (4) carrying out aging treatment on the extruded section in the fifth step, wherein the aging temperature is 174 ℃, and the aging time is 4.0h.

Example 6

A high-performance low-carbon secondary aluminum extruded section comprises the following chemical components in percentage by mass: 0.71% of Si, 0.65% of Mg, 0.4% of Cu, 0.32% of Fe, 0.16% of Cr, 0.41% of Mn, 0.07% of Ti, 0.07% of Zn, 0.14% of the total content of three elements of Mo, V and Zr, and the balance of Al and inevitable impurities, wherein the content of each impurity element is not more than 0.05%, the total content of the impurities is not more than 0.15%, and the use ratio of 6xxx series waste aluminum in raw materials to the recovered pop can is 70%.

The procedure for the preparation of example 6 corresponds to example 1, with the difference that:

step four, performing two-step homogenization heat treatment on the obtained semi-continuous casting bar, wherein the homogenization temperature in the step one is 500 ℃, and the heat preservation time is 5.0 hours, and the homogenization temperature in the step two is 580 ℃, and the heat preservation time is 1.0 hour;

step five: and (4) extrusion molding. Extruding the bar material after the homogenization treatment obtained in the step four, wherein the temperature of an extrusion outlet is 532 ℃, and the extrusion speed of a pressure head is 2.0mm/s;

step six: and (5) aging treatment. And (4) carrying out aging treatment on the extruded section obtained in the fifth step, wherein the aging temperature is 127 ℃, and the aging time is 2.0h.

Example 7

A high-performance low-carbon secondary aluminum extruded section comprises the following chemical components in percentage by mass: 0.75% of Si, 0.72% of Mg, 0.28% of Cu, 0.26% of Fe, 0.1% of Cr, 0.25% of Mn, 0.01% of Ti, 0.11% of Zn, 0.1% of the total content of Mo, V and Zr, and the balance of Al and inevitable impurities, wherein the content of each impurity element is not more than 0.05%, the total content of impurities is not more than 0.15%, and the use ratio of the 6xxx series waste aluminum recovered from raw materials to the recovered pop can is 83%.

The procedure for the preparation of example 7 corresponds to that of example 1, with the difference that:

step four, performing two-step homogenization heat treatment on the obtained semi-continuous casting bar, wherein the homogenization temperature in the step one is 520 ℃, and the heat preservation time is 2.0h, and the homogenization temperature in the step two is 560 ℃, and the heat preservation time is 2.0h;

step five: and (4) extrusion molding. Extruding the bar material after the homogenization treatment obtained in the fourth step, wherein the extrusion outlet temperature is 533 ℃, and the extrusion speed of a pressure head is 3.0mm/s;

step six: and (5) aging treatment. And (4) carrying out aging treatment on the extruded section in the fifth step, wherein the aging temperature is 189 ℃, and the aging time is 10.0h.

Example 8

A high-performance low-carbon recycled aluminum extruded section comprises the following chemical components in percentage by mass: 0.69% of Si, 0.67% of Mg, 0.48% of Cu, 0.39% of Fe, 0.19% of Cr, 0.44% of Mn, 0.04% of Ti, 0.14% of Zn, 0.08% of the total content of the three elements of Mo, V and Zr, and the balance of Al and inevitable impurities, wherein the content of each impurity element is not more than 0.05%, the total content of the impurities is not more than 0.15%, and the use ratio of 6xxx series waste aluminum in raw materials to the recovered pop can is 73%.

The procedure for the preparation of example 8 corresponds to example 1, with the difference that:

step four, performing two-step homogenization heat treatment on the obtained semi-continuous casting bar, wherein the homogenization temperature in the step one is 510 ℃, and the heat preservation time is 3.5 hours, and the homogenization temperature in the step two is 570 ℃, and the heat preservation time is 1.5 hours;

step five: and (4) extrusion forming. Extruding the bar material after the homogenization treatment obtained in the fourth step, wherein the extrusion outlet temperature is 541 ℃ and the extrusion speed of a pressure head is 4.0mm/s;

step six: and (5) aging treatment. And (4) carrying out aging treatment on the extruded section in the fifth step, wherein the aging temperature is 176 ℃, and the aging time is 8.0h.

Example 9

A high-performance low-carbon secondary aluminum extruded section comprises the following chemical components in percentage by mass: 0.63% of Si, 0.55% of Mg, 0.24% of Cu, 0.21% of Fe, 0.14% of Cr, 0.35% of Mn, 0.02% of Ti, 0.09% of Zn, 0.07% of the total content of the three elements of Mo, V and Zr, and the balance of Al and inevitable impurities, wherein the content of each impurity element is not more than 0.05%, the total content of the impurities is not more than 0.15%, and the use ratio of the 6xxx series waste aluminum recovered from raw materials to the recovered pop can is 84%.

The procedure for the preparation of example 9 is identical to that of example 1, with the difference that:

step four, performing two-step homogenization heat treatment on the obtained semi-continuous casting bar, wherein the homogenization temperature in the step one is 505 ℃, and the heat preservation time is 4.0h, and the homogenization temperature in the step two is 575 ℃, and the heat preservation time is 1.25h;

step five: and (4) extrusion forming. Extruding the bar material after the homogenization treatment obtained in the step four, wherein the temperature of an extrusion outlet is 555 ℃, and the extrusion speed of a pressure head is 6.0mm/s;

step six: and (5) aging treatment. And (4) carrying out aging treatment on the extruded section in the fifth step, wherein the aging temperature is 154 ℃, and the aging time is 3.0h.

Example 10

A high-performance low-carbon secondary aluminum extruded section comprises the following chemical components in percentage by mass: 0.56% of Si, 0.63% of Mg, 0.21% of Cu, 0.30% of Fe, 0.15% of Cr, 0.27% of Mn, 0.05% of Ti, 0.13% of Zn, 0.11% of the total content of Mo, V and Zr, and the balance of Al and inevitable impurities, wherein the content of each impurity element is not more than 0.05%, the total content of impurities is not more than 0.15%, and the use ratio of the 6xxx series waste aluminum in raw materials to the recovered pop can is 73%.

The procedure for the preparation of example 10 corresponds to example 1, with the difference that:

step four, performing two-step homogenization heat treatment on the obtained semi-continuous casting bar, wherein the homogenization temperature in the step one is 515 ℃, and the heat preservation time is 3.0 hours, and the homogenization temperature in the step two is 565 ℃, and the heat preservation time is 1.75 hours;

step five: and (4) extrusion forming. Extruding the bar material after the homogenization treatment obtained in the step four, wherein the temperature of an extrusion outlet is 552 ℃, and the extrusion speed of a pressure head is 2.0mm/s;

step six: and (5) aging treatment. And (4) carrying out aging treatment on the extruded section obtained in the fifth step, wherein the aging temperature is 136 ℃, and the aging time is 7.0h.

Table 1: EXAMPLES ingredient tables

Table 2: EXAMPLES Process tables

Through the above examples, the applicant found that trace amount of Fe can be combined with Al, mn, cr and Si elements to precipitate nanoscale finely dispersed AlMnCrFeSi dispersed phase particles in the aluminum alloy homogenization treatment process, and pinning and moving are carried out in the subsequent extrusion forming processThe formation of a completely recrystallized structure is suppressed by dynamic dislocations and subgrain boundaries. With the increase of Fe content, the nano-scale dispersed phase particles will continue to grow into micron-scale coarse needle-like brittle iron-rich phase. The thick needle-shaped iron-rich phase can not only cause adverse effect on the mechanical property of the alloy, but also consume Si element in the alloy system, thereby reducing Mg in the alloy system₂The amount of Si reinforcement weakens Mg₂The solid solution aging strengthening effect of the Si particles. The inventor finds that adding a small amount of Mo, V and Zr into an alloy system not only can transform a coarse acicular iron-rich phase into a short rod and a fine particle, but also can form new AlMSi dispersed phase particles (M is at least one element of Fe, mo, V and Zr) in the aging treatment process, play a role in precipitation strengthening, compensate the loss of mechanical properties caused by the increase of Fe content, and enable the alloy to have good tensile property.

Furthermore, the inventors have found that when the composition interval of Mn is 0.45 to 0.55% and the composition interval of Cr is 0.1 to 0.15%, the microstructure after extrusion can be made to assume a partially recrystallized morphology by adding a certain amount of Mo, V and Zr to the alloy. Wherein a large number of subboundaries and dislocations induced by the squeeze deformation exist in the unrecrystallized grains. A large number of dislocations can accelerate the diffusion speed of Mo, zr and V, so that atoms of the three elements which are dissolved in the aluminum matrix are accelerated to diffuse to the formed subboundary in the extrusion process, the energy of the subboundary is reduced, the fracture resistance of the subboundary is improved, and the bending performance of the material is improved. Experiments prove that when the addition ratio of Mo, V and Zr is controlled to be less than 0.05%, the content of atoms dissolved in the aluminum matrix during the 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 do not increase the atomic content ratio dissolved in the aluminum matrix. From the above, when the addition ratio of Mo, V and Zr is controlled to be in the range of 0.05 to 0.15%, the bending property of the alloy material is best.

In addition, two-step homogenization treatment is essential to increase the solid solubility of Mo, V and Zr in the aluminum matrix. After the low melting point eutectic product is dissolved by the first homogenization treatment at 500-520 ℃, the temperature is advantageously raised to 560-580 ℃ in the second homogenization treatment, which ensures that enough Mo, V and Zr atoms are dissolved in the aluminum matrix. Preheating the alloy before extrusion processing, wherein the preheating temperature is not lower than 500 ℃, the extrusion outlet temperature is between 530 and 560 ℃, the extrusion ratio is not less than 15, and the extrusion speed of a pressure head is between 2.0 and 6.0 mm/s. Under the extrusion process parameters, the obtained iron-rich phase in the product has smaller size, more round appearance and most uniform distribution of various dispersion strengthening phases, and the bending performance of the material can be remarkably improved under the condition of not losing the tensile performance.

All of the embodiments described above are only a part of the embodiments of the present invention, and not all of them. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Claims

1. The utility model provides a high performance low carbon regeneration aluminium extruded profile which characterized in that: the chemical components by mass percent are as follows: 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 Fe, 0.1 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, wherein the content of each impurity element is not more than 0.05 percent, and the total content of the impurities is not more than 0.15 percent.

2. The high-performance low-carbon secondary aluminum extruded profile as claimed in claim 1, wherein: the chemical components by mass percent are as follows: 0.6 to 0.75 percent of Si, 0.5 to 0.65 percent of Mg, 0.1 to 0.3 percent of Cu, 0.2 to 0.4 percent of Fe, 0.1 to 0.2 percent of Cr, 0.4 to 0.55 percent of Mn, less than or equal to 0.1 percent of Ti, less than or equal to 0.1 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, wherein the content of each impurity element is not more than 0.05 percent, the total content of the impurities is not more than 0.15 percent, and the proportion of recovered aluminum is not less than 70 percent.

3. The high-performance low-carbon secondary aluminum extruded profile as claimed in claim 1 or 2, wherein: extruded aluminium profiles are composed of a partially recrystallized structure and contain a large number of finely dispersed fibrous intermetallic compounds.

4. The high-performance low-carbon secondary aluminum extruded profile as claimed in claim 3, wherein: the intermetallic compound is mainly two granular precipitated phases: one is an AlMnCrFeSi phase; the other is an AlMSi phase, and M is at least one element of Fe, mo, V and Zr.

5. The high-performance low-carbon recycled aluminum extruded profile as claimed in any one of claims 1 to 4, wherein the high-performance low-carbon recycled aluminum extruded profile is characterized in that: the tensile yield strength of the secondary aluminum extruded profile in the extrusion direction is not lower than 280MPa, and the 2mm equivalent bending angle obtained by bending test of the alloy in the vertical extrusion direction is not lower than 80 degrees.

6. The preparation method of the high-performance low-carbon recycled aluminum extruded profile according to any one of claims 1 to 5, characterized by comprising the following steps:

the method comprises the following steps: alloy smelting, namely raising the temperature of a smelting furnace to be not lower than 700 ℃, putting the recovered aluminum, the intermediate alloy containing the required elements and a small amount of pure aluminum into the furnace in batches for melting, and after the aluminum is completely melted, refining and degassing to obtain a primary aluminum melt;

step two: alloy refining, namely sampling and analyzing the aluminum melt, supplementing metal elements or intermediate alloy to adjust the aluminum melt to target components of the aluminum alloy, and refining and degassing to obtain a refined alloy melt of the required target components;

step three: casting a bar, namely preparing the aluminum alloy cast bar with the target component from the refined solution obtained in the step two by adopting a semi-continuous casting method;

step four: homogenizing, namely performing one-step homogenizing or two-step homogenizing treatment on the semi-continuous casting bar obtained in the third step, wherein the homogenizing treatment temperature is 500-580 ℃;

step five: extrusion molding, namely extruding the homogenized bar obtained in the fourth step, wherein the extrusion preheating temperature of the alloy is not lower than 480 ℃, and the extrusion outlet temperature is 530-560 ℃;

step six: and (4) aging treatment, namely performing aging treatment on the extruded section in the fifth step, wherein the aging temperature is 120-195 ℃, and the aging time is 2.0-10.0 h.

7. The preparation method of the high-performance low-carbon recycled aluminum extruded profile as claimed in claim 6, wherein the preparation method comprises the following steps: the mass percent of the recycled aluminum used in the first step and the second step is more than or equal to 70 percent, wherein the mass percent of the 6xxx series aluminum scrap is more than or equal to 20 percent, and the mass percent of the pop can aluminum scrap is more than or equal to 30 percent; step four, adopting one-step homogenization heat treatment, and keeping the temperature at 530-550 ℃ for 2.0-5.0 h.

8. The preparation method of the high-performance low-carbon recycled aluminum extruded profile as claimed in claim 6 or 7, wherein the preparation method comprises the following steps: step four adopts two-step homogenization heat treatment, firstly, the temperature is kept at 500-520 ℃ for 2.0-5.0 h, and then the temperature is kept at 560-580 ℃ for 1.0-2.0 h.

9. The preparation method of the high-performance low-carbon recycled aluminum extruded profile as claimed in claim 6 or 7, wherein the preparation method comprises the following steps: in the fifth step, the extrusion preheating temperature of the alloy is not lower than 500 ℃, the extrusion outlet temperature is 540-550 ℃, the extrusion ratio is not less than 15, and the extrusion speed of a pressure head is 2.0-6.0 mm/s.

10. The preparation method of the high-performance low-carbon recycled aluminum extruded profile as claimed in any one of claims 6 to 9, wherein the preparation method comprises the following steps: the aging treatment in the sixth step is two-step aging heat treatment, the aging temperature is between 150 and 190 ℃, and the single-step aging treatment time is not more than 3.0h.

11. The high-performance low-carbon recycled aluminum extruded profile and the application of the preparation method thereof according to any one of the preceding claims, wherein the high-performance low-carbon recycled aluminum extruded profile is characterized in that: the prepared regenerated extruded aluminum profile is used for photovoltaic power generation equipment and new energy electric automobile parts.

12. The high-performance low-carbon recycled aluminum extruded profile and the application of the preparation method thereof as claimed in claim 11, wherein the application is characterized in that: the prepared regenerated extruded aluminum profile is used for components such as an anti-collision beam, a threshold beam, a floor beam, a water tank upper beam and the like of a new energy electric automobile.