6-series high-strength aluminum alloy, processing technology and application of 6-series high-strength aluminum alloy in solar photovoltaic structural member

Abstract

The invention relates to the technical field of aluminum alloys, in particular to a 6-series high-strength aluminum alloy, a processing technology and application of the 6-series high-strength aluminum alloy in a solar photovoltaic structural member. The 6-series aluminum alloy material comprises the following components: 0.6-0.9 wt% of Si, 0.8-1.1 wt% of Mg, 0.4-0.7 wt% of Cu, less than or equal to 0.2 wt% of Mn, less than or equal to 0.1 wt% of Cr, less than or equal to 0.1 wt% of Zn, less than or equal to 0.1 wt% of Ti, less than or equal to 0.3 wt% of Fe and the balance of Al and inevitable impurities. By adopting the 6-series aluminum alloy designed by the invention, the performance requirement that the yield strength of an extruded profile of a solar photovoltaic structural member is greater than 320 MPa can be met, so that the new high-strength aluminum alloy material can be used for carrying out reduced section design of the solar photovoltaic structural member, and the effects of lighter weight and lighter weight are achieved; the use cost of the material is greatly reduced; and meanwhile, the situation that recrystallization of the extruded material is too thick, and too thick extrusion recrystallization causes bad influence on the appearance of the anode can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to a 6-series high-strength aluminum alloy, a processing technology and an application thereof in solar photovoltaic structural parts. Background Art

[0002] 6 series aluminum alloy is an aging-strengthened aluminum alloy with many advantages such as low density, wide range of mechanical properties, excellent plastic formability, good thermal conductivity, weather resistance, and corrosion resistance. It can be applied to various service environments, and its extruded profiles have been increasingly widely used in emerging strategic manufacturing industries such as new energy, electronic information, and transportation. Among them, solar photovoltaic structural parts, including frames and brackets, all use 6 series aluminum alloy profiles on a large scale, with a market demand of more than one million tons.

[0003] In the application history of 6 series aluminum alloy profiles in solar photovoltaic structural parts, the mainstream material before 2019 was Al6063 aluminum alloy, with a yield strength of 180-220MPa. Due to the low yield strength, the thickness of the cross-section design of the structural parts at that time was mostly thicker, in order to make up for the defect of low yield strength and meet the requirements of wind resistance, snow resistance, rain resistance and other natural external forces in the use scenario. However, the thicker thickness increases the amount of material used and increases a lot of material costs. Therefore, after 2020, the mainstream material has become the stronger Al6005 aluminum alloy with a yield strength of 240-280MPa. Since the yield strength has been greatly improved, the thickness of the cross-section design of the structural parts can be thinned, reducing the amount of material used and thus reducing costs.

[0004] From 2020 to now, the mainstream material has been using Al6005, and no new materials have been applied to further reduce weight. This is mainly because other materials such as Al6013, Al6066, Al6082, etc. are not suitable for use in solar photovoltaic structural parts due to factors such as high material cost, poor extrusion formability, and poor anodizing effect. Therefore, if you want to further optimize the cross-sectional design for lightweighting and weight reduction, you must invent a new type of 6 series aluminum alloy material with a yield strength much higher than Al6005, and with excellent extrusion formability and excellent anodized appearance.

[0005] The new material of the invention is a 6 series aluminum alloy profile, which is the first to be used in solar photovoltaic structural parts. It is characterized by a yield strength greater than 320MPa, which is much higher than the 240-280MPa of Al6005, and has excellent extrusion formability and anodized appearance. It can be used in solar photovoltaic structural parts, making the lightweight and weight-reducing cross-sectional design more flexible, and thus making more optimized designs. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a 6-series high-strength aluminum alloy, a processing technology and its application in solar photovoltaic structural parts. The components of the 6-series aluminum alloy material include 0.6-0.9wt% Si, 0.8-1.1wt% Mg, 0.4-0.7wt% Cu, ≤0.2wt% Mn, ≤0.1wt% Cr, ≤0.1wt% Zn, ≤0.1wt% Ti, ≤0.3wt% Fe, and the remaining components are composed of Al and inevitable impurities; the 6-series aluminum alloy designed by the patent of the present invention can meet the performance requirements of the yield strength of the extruded profile of the solar photovoltaic structural parts greater than 320MPa, and then this high-strength aluminum alloy new material can be used to design the weight-reducing new section of the solar photovoltaic structural parts, so that it can achieve a more lightweight and weight-reducing effect, and greatly reduce the cost of using the material; at the same time, it can avoid the recrystallization of the material after extrusion being too coarse, and the excessively coarse extrusion recrystallization will have an adverse effect on the appearance of the anode.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A 6 series high-strength aluminum alloy comprises the following components: 0.6-0.9wt% Si, 0.8-1.1wt% Mg, 0.4-0.7wt% Cu, ≤0.2wt% Mn, ≤0.1wt% Cr, ≤0.1wt% Zn, ≤0.1wt% Ti, ≤0.3wt% Fe, and the balance consists of Al and unavoidable impurities.

[0009] The Si and Cu composition ranges of the new material of the present invention do not overlap with those of Al6063, and the Si and Cu compositions are higher than those of Al6063. The Mg composition range overlaps by more than 0.1%, and is higher than that of Al6063. The increase in the composition of Si, Mg, and Cu makes the precipitation amount of the strengthening phase Mg2Si of the present material much greater than that of Al6063, and more strengthening phases containing Cu, such as Al2Cu, are precipitated. Therefore, the yield strength of the present material is much higher than that of Al6063 aluminum alloy. The yield strength of Al6063 aluminum alloy is 180-220MPa, and the yield strength of the present material is ≥320MPa.

[0010] The Mg and Cu composition ranges of the new material of the present invention do not overlap with those of Al6005. Although the Si composition range overlaps, the Mg and Cu composition ranges are higher than those of Al6005, so that the material precipitates more strengthening phases Mg2Si, and also precipitates more strengthening phases containing Cu such as Al2Cu, so the yield strength of the material is higher than that of Al6005 aluminum alloy. The yield strength of Al6005 aluminum alloy is 240-280MPa, and the yield strength of the material is ≥320MPa.

[0011] The Cu component range of the new material of the present invention does not overlap with that of Al6061, and the Cu component is higher than that of Al6061. Although the Si component range of Al6061 overlaps by 0.2% and the Mg component range overlaps by 0.3% compared with the present material, and the precipitation amount of the strengthening phase Mg2Si is relatively close, the Cu component range of the present material is higher than that of Al6061, and more Cu-containing strengthening phases such as Al2Cu will be precipitated than Al6061, so the yield strength of the present material is higher than that of Al6061 aluminum alloy. The yield strength of Al6061 aluminum alloy is 240-310MPa, and the yield strength of the present material is ≥320MPa.

[0012] The Mn component range of the new material of the present invention does not overlap with that of Al6013, and the Mn component is lower than that of Al6013. Although compared with Al6013, the component ranges of Si and Mg overlap by 0.3%, and the precipitable amount of the strengthening phase Mg2Si is relatively close, the Cu component range of Al6013 is higher than that of the present material except for the overlap of 0.1%, so the precipitable amount of the Cu-containing strengthening phase such as Al2Cu of Al6013 can be more, and the yield strength can be greater than that of the present material. However, the Mn content of Al6013 is in the range of 0.2-0.8%. The high Mn content is easy to form (Al, Mn, Fe, Si) or (Al, Mn, Fe) intermetallic compounds such as Al6 (Mn, Fe) 3Si. This Mn-containing intermetallic compound will hinder the development of recrystallized grain boundaries during the extrusion process, and then form a coarse or less uniform recrystallized structure, which has a more adverse effect on the appearance and mechanical properties of the anode. For example, coarse grains are prone to corrosion at the anode, resulting in the formation of anode spots. Therefore, the Mn content of this material is designed to be less than 0.2%, which can make the extruded recrystallized grains smaller and more uniform than Al6013, thereby obtaining better anodic oxidation performance. In addition, compared with Al6013, the lower Mn content range and lower Cu content range of this material will make the extrusion performance higher than Al6013, and the production efficiency of solar photovoltaic structural parts can be much better than Al6013.

[0013] The Si, Mg, Cu, and Mn component ranges of the new material of the present invention do not overlap with those of Al6066. The Si and Mg component ranges of Al6066 are higher than those of the present material, and more strengthening phases Mg2Si can be precipitated. In addition, the Cu component range is higher than that of the present material, and more Cu-containing strengthening phases such as Al2Cu can be precipitated, so Al6066 can achieve a yield strength of more than 400MPa. However, excessive Si, Mg, and Cu will cause the appearance of the anode to deteriorate and the color to darken. In addition, the yield strength of more than 400MPa is too high, which may not necessarily lead to better benefits for the lightweighting of solar photovoltaic structural parts. At the same time, the extrusion performance will be greatly reduced, and the extrusion production difficulty is too large for thin and light sections. The ultra-high Mn component range of 0.6-1.1% will also form more Mn-containing intermetallic compounds, making recrystallization more difficult and further reducing the performance of anodizing.

[0014] The Cu and Mn component ranges of the new material of the present invention do not overlap with those of Al6082, the Si component range is higher than that of the present material except for the overlap of 0.2%, and the Mg component range is higher than that of the present material except for the overlap of 0.3%. Al6082 contains almost no Cu, and the strength can only be improved by the higher Si and Mg component ranges. When the Si and Mg components are much higher than those of the present material, the color of the anode becomes dark. The higher Mn component range of 0.4-1.0% will also form more Mn-containing intermetallic compounds, making recrystallization more difficult and further reducing the performance of anodizing.

[0015] Preferably, the composition of the 6 series high-strength aluminum alloy is further limited to 0.71wt% Si, 0.91wt% Mg, 0.65wt% Cu, 0.07wt% Mn, 0.012wt% Cr, 0.023wt% Zn, 0.012wt% Ti, 0.11wt% Fe, and the remaining components are composed of Al and unavoidable impurities.

[0016] A processing technology for 6 series high-strength aluminum alloy, used for preparing the 6 series high-strength aluminum alloy, comprises the following steps:

[0017] S1. Aluminum alloy casting:

[0018] S101. Melting: Al ingots, Mg ingots, Cu ingots, and Al-Si and Al-Mn master alloys are placed in a melting furnace and melted into an aluminum alloy solution according to a specified component ratio;

[0019] S102. Tempering: sampling the aluminum alloy solution to quickly analyze the composition, adding metal elements to temper the aluminum alloy to a set composition range, and then slagging, refining and standing the aluminum alloy solution;

[0020] S103 casting: the aluminum alloy solution processed in step S102 flows into the casting mold through the flow channel, and the aluminum alloy solution is cast through the mold to obtain a cast rod;

[0021] S2. Homogenization treatment: The cast rod obtained in step S1 is heated to 540-580°C at a rate of 30-100°C / h, and kept warm for 6-24 hours. After the insulation is completed, it is cooled to below room temperature at a rate of 100-200°C / h, thereby completing the monopolar homogenization treatment;

[0022] S3. Extrusion: The homogenized cast rod is subjected to aluminum extrusion. After the extruded profile comes out, it is cooled by water spray for online quenching;

[0023] S4. Artificial aging treatment: The profile obtained by step S3 is heated to 170-200°C, kept at this temperature for 3-18 hours, and then cooled to room temperature by strong wind after being taken out of the furnace, thereby completing the monopolar artificial aging treatment and obtaining the 6 series high-strength aluminum alloy.

[0024] The heating speed of monopolar homogenization is slow. During the slow heating process, part of the low-temperature soluble phase of MgSi or AlCu will be dissolved back into the aluminum base. In this way, when the temperature reaches 540-580℃, most of the dissolution kinetic energy can be used to dissolve the coarser soluble phase, thereby promoting the effect of homogenization treatment.

[0025] The implementation of unipolar artificial aging is simply heating to the optimal precipitation temperature range of the Mg2Si strengthening phase. Within the optimal precipitation temperature range, the higher the artificial aging temperature is set, the shorter the holding time is, for example, heating to 200°C and holding for 3 hours; and the lower the artificial aging temperature is set, the longer the holding time is, for example, heating to 170°C and holding for 18 hours. This is because if the artificial aging temperature is too high and the holding time is too long, over-aging will occur, resulting in coarsening of the Mg2Si phase, reducing the hardening effect of artificial aging; and if the artificial aging temperature is too low and the holding time is too short, the Mg2Si strengthening phase will not have time to precipitate to the relative peak value of quantity and density, and better mechanical properties cannot be obtained.

[0026] Preferably, in step S103, plate filtration treatment may be performed in the flow trough process.

[0027] Preferably, in step S103, ≤0.2wt% of aluminum titanium boron wire can be added during the laundering process to refine the casting grains.

[0028] Preferably, in step S103, the mold plate is a hot top type or an oil-gas sliding type.

[0029] Preferably, step S2 can also be performed by bipolar homogenization treatment to treat the cast rods, specifically comprising the following steps: heating the cast rods to 500-540°C at a rate of 100-200°C / h, keeping the temperature for 2-6 hours, then heating the cast rods to 550-580°C at a rate of 100-200°C / h, keeping the temperature for 6-20 hours, and then cooling the cast rods to below room temperature at a rate of 100-200°C / h to complete the bipolar homogenization treatment.

[0030] The heating speed of bipolar homogenization is fast. Most of the MgSi or AlCu low-temperature soluble phases do not have time to dissolve back into the aluminum base. Therefore, the first pole is set to a low temperature of 500-540℃ for a short time to dissolve part of the MgSi or AlCu low-temperature soluble phase back into the aluminum base, and then the second pole is heated to 550-580℃ for a long time. At this time, most of the dissolution kinetic energy can be used to dissolve the coarser soluble phase, so that the homogenization effect is improved.

[0031] Preferably, in step S3, the working parameters of the aluminum extrusion process are: mold heating temperature is 430-480°C; ingot barrel heating temperature is 430-480°C; cast rod heating temperature is 470-550°C; extrusion rod pushing speed during extrusion is 3-6mm / s; extrusion outlet temperature is 480-560°C; the temperature of the profile after online quenching and extrusion is below 200°C; the elongation rate of the profile after aluminum extrusion is below 0.5%.

[0032] Preferably, step S4 can also treat the profile by bipolar artificial aging treatment, which specifically includes the following steps: heating the profile to 100-130° C. and keeping it warm for 2-4 hours; then heating it to 160-180° C. and keeping it warm for 4-10 hours.

[0033] The implementation of bipolar artificial aging is mainly to obtain a large number of dense Mg2Si strengthening phases, thereby obtaining the best mechanical properties. The first pole is set to a low temperature of 100-130℃ for a short time of insulation, the purpose is to form a large number of dense GPZone nuclei in the aluminum base. These GPZone nuclei will continue to grow and transform into a large number of dense Mg2Si strengthening phases when the second pole is heated to 160-180℃, thereby improving the effect of artificial aging and obtaining better mechanical properties.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The 6-series aluminum alloy designed by the patent of this invention can meet the performance requirement of the yield strength of the extruded profile of solar photovoltaic structural parts greater than 320MPa. This high-strength aluminum alloy new material can be used to design the weight-reduced new section of solar photovoltaic structural parts, so that it can achieve a more lightweight and weight-reduced effect, greatly reducing the cost of using materials; at the same time, it can avoid the recrystallization of the material after extrusion being too coarse, and excessive extrusion recrystallization will have an adverse effect on the appearance of the anode. The high-strength characteristics of the new material of this invention are more suitable for the lightweight and weight-reducing application of solar photovoltaic structural parts;

[0036] 2. The new material of the patent of this invention is a 6-series high-strength aluminum alloy material with a yield strength greater than 320MPa. It is a pioneering work to use it in extruded profiles of solar photovoltaic structural parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a processing flow chart of the 6 series high strength aluminum alloy of the present invention;

[0038] Figure 2 It is a force-deformation curve diagram of the 6-series high-strength aluminum alloy described in Example 1 of the present invention;

[0039] Figure 3 It is a force-deformation curve diagram of the 6-series high-strength aluminum alloy described in Comparative Example 1 of the present invention;

[0040] Figure 4 It is a force-deformation curve diagram of the 6-series high-strength aluminum alloy described in Comparative Example 2 of the present invention;

[0041] Figure 5 It is a force-deformation curve diagram of the 6-series high-strength aluminum alloy described in Comparative Example 4 of the present invention;

[0042] Figure 6 It is a comparison diagram of extrusion recrystallization of Example 1 of the present invention and Comparative Example 4, wherein, (a): Example 1, (b) Comparative Example 4;

[0043] Figure 7 It is a comparison diagram of extrusion recrystallization between Example 1 of the present invention and Example 2 and Comparative Example 4, wherein: (a): Example 1, (b): Example 2, (c): Comparative Example 4. DETAILED DESCRIPTION

[0044] The present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than 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.

[0045] See also Figure 1-7 , the present invention provides a technical solution:

[0046] Example 1

[0047] A processing technology for 6 series high-strength aluminum alloy:

[0048] S1. Aluminum alloy casting:

[0049] S101. Melting: Al ingots, Mg ingots, Cu ingots, and Al-Si and Al-Mn master alloys are placed in a melting furnace and melted into an aluminum alloy solution according to a specified component ratio;

[0050] S102. Tempering: sampling the aluminum alloy solution to quickly analyze the composition, adding metal elements to temper the aluminum alloy to a set composition range, and then slagging, refining and standing the aluminum alloy solution;

[0051] S103 casting: the aluminum alloy solution processed in step S102 flows into the hot top casting mold through the flow channel, and the aluminum alloy solution is cast through the hot top casting mold to obtain a cast rod;

[0052] S2. Homogenization treatment: The cast rod obtained in step S1 is heated to 570°C at a rate of 30°C / h and kept at this temperature for 16 hours. After the insulation is completed, it is cooled to below room temperature at a rate of 100°C / h, thereby completing the monopolar homogenization treatment;

[0053] S3. Extrusion: The homogenized cast rod is subjected to aluminum extrusion. After the extruded profile comes out, it is cooled by water spray for online quenching;

[0054] S4. Artificial aging treatment: The profile obtained by the step S3 is heated to 180°C, kept at this temperature for 8 hours, and then cooled to room temperature by strong wind after being taken out of the furnace, thereby completing the monopolar artificial aging treatment and obtaining the 6 series high-strength aluminum alloy.

[0055] The operating parameters of the aluminum extrusion process are:

[0056] The heating temperature of the mold is 450℃; the heating temperature of the ingot barrel is 450℃; the heating temperature of the cast rod is 530℃; the extrusion rod pushing speed during extrusion is 4.5mm / s;

[0057] During the aluminum alloy casting process, the aluminum alloy composition is as follows:

[0058]

[0059] The balance consists of Al and inevitable impurities.

[0060] Embodiment 2: Embodiment 2 is different from Embodiment 1 in that, in the aluminum alloy casting process of Embodiment 2, the aluminum alloy composition is as follows:

[0061]

[0062] The balance components consist of Al and inevitable impurities, and the remaining steps in Example 2 are exactly the same as those in Example 1.

[0063] Example 3: Example 3 is different from Example 1 in that, in Example 3, step S2 originally existing in Example 1 is replaced, so that the cast rod is treated by bipolar homogenization. The bipolar homogenization treatment specifically includes the following steps: the cast rod is heated to 530°C at a rate of 100°C / h, kept warm for 3 hours, then heated to 570°C at a rate of 100°C / h, kept warm for 10 hours, and then cooled to below room temperature at a rate of 100°C / h to complete the bipolar homogenization treatment;

[0064] The remaining steps are exactly the same in Example 3 and Example 1.

[0065] Example 4: Example 4 is different from Example 1 in the following way. The only difference is that in Example 4, step S4 originally existing in Example 1 is replaced with the following step: heating the profile obtained by step S3 to 190°C, keeping it warm for 4.5 hours, and cooling it to room temperature with strong wind after taking it out of the furnace to obtain the 6 series high-strength aluminum alloy; the remaining steps are exactly the same in Example 4 and Example 1.

[0066] Example 5: Example 5 is different from Example 1 in the following way. The only difference is that in Example 5, step S4 originally existing in Example 1 is replaced, and the replaced step is: heating the profile obtained by step S3 to 200°C, keeping it warm for 2.5 hours, and cooling it to room temperature with strong wind after taking it out of the furnace to obtain the 6 series high-strength aluminum alloy; the remaining steps are exactly the same in Example 5 and Example 1.

[0067] Example 6: Example 6 is different from Example 1 in that, in Example 6, step S4 originally existing in Example 1 is replaced, so that the profile is treated by bipolar artificial aging. The bipolar artificial aging treatment specifically includes the following steps: heating the profile obtained by step S3 to 125° C. and keeping it warm for 2 hours; then heating it to 170° C. and keeping it warm for 8 hours, and cooling it to room temperature by strong wind after taking it out of the furnace to obtain the 6 series high-strength aluminum alloy; the remaining steps are exactly the same in Example 6 and Example 1.

[0068] Comparative Example

[0069] Comparative Example 1: Comparative Example 1 is the national standard (GB / T 3190-2020) 6 series aluminum alloy 6063, and its aluminum alloy composition is as follows:

[0070]

[0071] The balance components consist of Al and inevitable impurities, and the remaining steps in Comparative Example 1 are exactly the same as those in Example 1.

[0072] Comparative Example 2: Comparative Example 2 is a national standard (GB / T 3190-2020) 6 series aluminum alloy 6005, and its aluminum alloy composition is as follows:

[0073]

[0074] The balance components consist of Al and inevitable impurities, and the remaining steps in Comparative Example 2 are exactly the same as those in Example 1.

[0075] Comparative Example 3: Comparative Example 3 is the national standard (GB / T 3190-2020) 6 series aluminum alloy 6061, and its aluminum alloy composition is as follows:

[0076]

[0077] The balance components consist of Al and inevitable impurities, and the remaining steps in Comparative Example 3 are exactly the same as those in Example 1.

[0078] Comparative Example 4: Comparative Example 4 is a national standard (GB / T 3190-2020) 6 series aluminum alloy 6013, and its aluminum alloy composition is as follows:

[0079]

[0080] The balance components consist of Al and inevitable impurities, and the remaining steps in Comparative Example 4 are exactly the same as those in Example 1.

[0081] Comparative Example 5: Comparative Example 5 is a national standard (GB / T 3190-2020) 6 series aluminum alloy 6066, and its aluminum alloy composition is as follows:

[0082]

[0083] The balance components consist of Al and inevitable impurities, and the remaining steps in Comparative Example 5 are exactly the same as those in Example 1.

[0084] Comparative Example 6: Comparative Example 6 is a national standard (GB / T 3190-2020) 6 series aluminum alloy 6082, and its aluminum alloy composition is as follows:

[0085]

[0086] The balance components consist of Al and inevitable impurities, and the remaining steps in Comparative Example 6 are exactly the same as those in Example 1.

[0087] Comparative Example 7: Comparative Example 7 is different from Example 1 in that, during the aluminum alloy casting process of Comparative Example 7, the aluminum alloy composition is as follows:

[0088]

[0089] The balance components consist of Al and inevitable impurities, and the remaining steps in Comparative Example 7 are exactly the same as those in Example 1.

[0090] Comparative Example 8: Comparative Example 8 is different from Example 1 in that, during the aluminum alloy casting process of Comparative Example 8, the aluminum alloy composition is as follows:

[0091]

[0092] The balance components consist of Al and inevitable impurities, and the remaining steps in Comparative Example 8 are exactly the same as those in Example 1.

[0093] Comparative Example 9: Comparative Example 9 is different from Example 1 in that, during the aluminum alloy casting process of Comparative Example 9, the aluminum alloy composition is as follows:

[0094]

[0095] The balance components consist of Al and inevitable impurities, and the remaining steps in Comparative Example 9 are exactly the same as those in Example 1.

[0096] Comparative Example 10: Comparative Example 10 is different from Example 1 in that, during the aluminum alloy casting process of Comparative Example 10, the aluminum alloy composition is as follows:

[0097]

[0098] The balance components consist of Al and inevitable impurities, and the remaining steps in Comparative Example 10 are exactly the same as those in Example 1.

[0099] Comparative Example 11: Comparative Example 11 is different from Example 1 in that the working parameters of the aluminum extrusion process are as follows: the mold heating temperature is 450°C; the ingot barrel heating temperature is 450°C; the cast rod heating temperature is 460°C; the extrusion rod pushing speed during extrusion is 4.5 mm / s; and the remaining steps are exactly the same in Comparative Example 11 and Example 1.

[0100] Comparative Example 12: Comparative Example 12 is different from Example 1 in that the working parameters of the aluminum extrusion process are as follows: the mold heating temperature is 450°C; the ingot barrel heating temperature is 450°C; the cast rod heating temperature is 560°C; the extrusion rod pushing speed during extrusion is 4.5 mm / s; and the remaining steps are exactly the same in Comparative Example 12 and Example 1.

[0101] Comparative Example 13: Comparative Example 13 is different from Example 1 in the following way. The only difference is that in Comparative Example 13, in step S3, strong air cooling is used to replace water spray cooling for online quenching, and the remaining steps are exactly the same in Comparative Example 13 and Example 1.

[0102] Performance test: The yield strength, tensile strength, hardness and elongation of the 6-series high-strength aluminum alloy for solar photovoltaic structural parts prepared in Examples 1-6 and Comparative Examples 1-13 were tested, and the test results are as follows:

[0103] The mechanical properties of the new materials of Examples 1 and 3 of the present invention after different homogenization treatment methods are compared as follows:

[0104]

[0105] The homogenization treatment methods of Example 1 monopolar 570℃x16h and Example 3 bipolar 530℃x3h+570℃x10h were studied to confirm the influence of different homogenization treatments on the mechanical properties after extrusion. The yield strength of Example 1 monopolar 570℃x16h is 336MPa, and the yield strength of Example 3 bipolar 530℃x3h+570℃x10h is 338MPa, which proves that as long as the temperature and time ratio of homogenization are properly designed, the monopolar or bipolar homogenization conditions have little effect on the mechanical properties after extrusion.

[0106] The mechanical properties of the new materials of Examples 1, 4, 5, and 6 of the present invention in different artificial aging methods are compared as follows:

[0107]

[0108] The artificial aging methods of Example 1 monopolar 180℃x8h, Example 4 monopolar 190℃x4.5h, Example 5 monopolar 200℃x2.5h, and Example 6 bipolar 125℃x2h+170℃x8h were studied to confirm the influence of artificial aging methods on mechanical properties after extrusion. The yield strength of Example 1 monopolar 180℃x8h is 336MPa, the yield strength of Example 4 monopolar 190℃x4.5h is 339MPa, the yield strength of Example 5 monopolar 200℃x2.5h is 328MPa, and the yield strength of Example 6 bipolar 125℃x2h+170℃x8h is 342MPa, which proves that as long as the temperature and time ratio of artificial aging are properly designed, different artificial aging methods can make the new material of the present invention reach the yield strength requirement of 320MPa. However, in the high temperature and short time embodiment 5, the monopolar type 200℃x2.5h, because of the high temperature, the precipitated Mg2Si strengthening phase will be relatively larger and less dense, so the yield strength is relatively lower; while in the bipolar type 125℃x2h+170℃x8h of embodiment 6, because of the short time insulation at the low temperature of 125℃, a large number of dense GPZone nuclei are formed in the aluminum base, and these GPZone nuclei will continue to grow and transform into a large number of dense Mg2Si strengthening phases when the second high temperature 170℃ is maintained, thereby improving the effect of artificial aging and obtaining better mechanical properties.

[0109] The mechanical properties of the embodiment and the national standard comparison example are as follows:

[0110]

[0111] The mechanical properties of this embodiment and the comparative example show that the yield strength of comparative example 1: 6063, comparative example 2: 6005, and comparative example 3: 6061 cannot meet the requirement of the yield strength greater than 320MPa defined by the new material of the present invention. When the Si and Mg components of comparative example 3: 6061 are similar to those of the new material of the present invention and the Cu component is 0.22%, the yield strength cannot be increased to more than 320MPa, so the design of the Cu component must exceed 6061, and the Cu component of the new material of the present invention is defined at 0.4-0.7%. In addition, although the yield strength of comparative example 5: 6066 is much higher than 320MPa, it is difficult to extrude and has poor anode performance, so it is not suitable for application in solar photovoltaic structural parts. The Mg, Si and Cu components of comparative example 4: 6013 are close to those of the new material of the present invention, and the yield strength reaches 323 MPa. The yield strength of comparative example 6: 6082 reaches 315 MPa when the Si component is 1.08% and the Mg component is 0.72%. However, the Mn components of both are high. In addition to the low extrusion efficiency, the most important thing is that the anode appearance is prone to spots, and the anodizing performance is poor.

[0112] Figure 2 , 3 , 4, and 5 are force-deformation curves of Example 1 of the present invention, Comparative Examples 1, 2, and 4, respectively. As shown in the figure: Comparative Example 1: The yield strength of 6063 is only 208MPa, which is far lower than the yield strength of 336MPa of Example 1 of the new material of the present invention. Comparative Example 2: The yield strength of 6005 can reach 268MPa, which is still lower than the yield strength of 336MPa of Example 1 of the new material of the present invention. Comparative Example 4: The yield strength of 6013 can reach 323MPa, which is relatively equivalent to the yield strength of 336MPa of Example 1 of the new material of the present invention, and can be greater than 320MPa.

[0113] Figure 6 This is a comparison diagram of extrusion recrystallization of Example 1 of the present invention and Comparative Example 4, as shown in the figure: the Si, Mg, and Cu components of Comparative Example 4 are similar to those of the new material of the present invention, and the yield strength is also equivalent to that of the new material of the present invention, which can be greater than 320MPa. The Mn element with a relatively large difference in composition is 0.07% of the new material of Example 1 of the present invention and 0.28% of Comparative Example 4. After extrusion, metallographic observation under an optical microscope was carried out, and it was found that the recrystallization structure of the embodiment is very uniform, with the largest grain at 277um; while the recrystallization structure of Comparative Example 4 is very uneven, with many small recrystallization structures, and the largest grain has reached 789um. Therefore, unlike Comparative Example 4, the Mn component of the new material of the present invention is defined as below 0.2%, which can obtain a more uniform and delicate recrystallized grain structure, thereby obtaining the best anodizing effect.

[0114] The mechanical properties of the embodiments and comparative examples of the new material of the present invention with different Si and Mg contents are as follows:

[0115]

[0116] The mechanical properties of Example 1 with Si: 0.71%, Mg: 0.89% and Comparative Example 7 with Si: 0.58%, Mg: 0.78%, and Comparative Example 8 with Si: 0.93%, Mg: 1.13% after extrusion were studied to confirm the conditions of the limit range of Si and Mg components. The yield strength of Comparative Example 7 with low Si and low Mg is only 308MPa, which is lower than the yield strength requirement of 320MPa of the material of the present invention. Si or Mg can be increased separately, or the extrusion casting temperature can be increased to achieve a yield strength of more than 320MPa. The yield strength of Comparative Example 8 with high Si and high Mg can reach 382MPa, but the extrusion speed is only 1 / 2 of that of Example 1, which is not suitable for mass production.

[0117] The mechanical properties of the embodiments of the new material of the present invention with different Cu contents and the comparative examples are compared as follows:

[0118]

[0119] The mechanical properties after extrusion of Example 1 with Cu: 0.65% and Example 9 with low Cu: 0.38% and high Cu: 0.71% were studied to confirm the condition of the limit range of Cu composition. The yield strength of Example 9 with low Cu is 317MPa, which is slightly lower than the requirement of 320MPa of the yield strength of the material of the present invention. The yield strength of 320MPa or more can be reached by increasing the Si or Mg content or increasing the extrusion casting temperature, but the aforementioned methods will reduce the extrusion speed. The yield strength of Example 10 with high Cu is 345MPa, which meets the yield strength requirement of 320MPa or more, and the extrusion efficiency is not much different from that of Example 10 with Cu 0.65%, but the higher the Cu content, the higher the cost.

[0120] The mechanical properties of the embodiments of the new material of the present invention with different Mn contents and the comparative examples are compared as follows:

[0121]

[0122] The mechanical properties after extrusion of Example 1 with low Mn: 0.07%, Example 2 with Mn: 0.18%, and Comparative Example 4 with high Mn: 0.28% were studied to confirm the different conditions of Mn content. The yield strength of Example 1 with low Mn: 0.07% is 336MPa, the yield strength of Example 2 with Mn: 0.18% is 334MPa, and the yield strength of Comparative Example 4 with high Mn: 0.28% is 328MPa, all of which meet the yield strength of more than 320MPa. The data proves that the Mn content has little effect on the mechanical properties after extrusion.

[0123] Figure 7 This is a comparison diagram of the extrusion recrystallization of the embodiments and comparative examples of the new material of the present invention with different Mn contents, as shown in the figure: although the low Mn: 0.07% in embodiment 1 and the Mn: 0.18% in embodiment 2 and the high Mn: 0.28% in comparative example 4 have little effect on the mechanical properties after extrusion, they have a significant effect on the recrystallization structure after extrusion. The recrystallization structure of the low Mn: 0.07% in embodiment 1 is very uniform, and the largest grain is only 277um. This kind of uniform recrystallization structure with smaller particles has a better anodizing effect. The recrystallization structure of Mn: 0.18% in embodiment 2 is less uniform than that of embodiment 1, and the recrystallization particles are large and small, with the largest grain being 542um. The recrystallization structure of the high Mn: 0.28% in comparative example 4 is very uneven, with many broken and small recrystallization structures, and the largest grain has reached 789um. This very uneven recrystallization structure has a poor anodizing effect.

[0124] The mechanical properties of the embodiments and comparative examples of the new material of the present invention at different extrusion casting temperatures are compared as follows:

[0125]

[0126] The study of the extrusion casting temperature of 530°C in Example 1, the extrusion casting temperature of 460°C in Comparative Example 11, and the extrusion casting temperature of 560°C in Comparative Example 12 was conducted to confirm the influence of the extrusion casting temperature on the mechanical properties after extrusion. The yield strength of the extrusion casting temperature of 530°C in Example 1 is 336MPa, the yield strength of the extrusion casting temperature of 460°C in Comparative Example 11 is 290MPa, and the yield strength of the extrusion casting temperature of 560°C in Comparative Example 12 is 373MPa, which proves that the extrusion casting temperature has a greater influence on the mechanical properties after extrusion. In the case of low Si, low Mg or low Cu, the mechanical properties after extrusion can be improved by increasing the extrusion temperature.

[0127] The mechanical properties of the embodiments and comparative examples of the new material of the present invention with different extrusion outlet cooling methods are compared as follows:

[0128]

[0129] The water spray cooling of Example 1 and the strong wind cooling of Comparative Example 13 were studied to confirm the influence of the cooling method of the extrusion outlet on the mechanical properties after extrusion. The yield strength of the water spray cooling of Example 1 is 336MPa, and the yield strength of the strong wind cooling of Comparative Example 13 is 285MPa, which proves that the cooling method of the extrusion outlet has a key influence on the mechanical properties after extrusion. The stronger the cooling intensity of the extrusion outlet, the better the mechanical properties.

[0130] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A 6 series high strength aluminum alloy, It is characterized in that The invention comprises the following components: 0.6-0.9wt% Si, 0.8-1.1wt% Mg, 0.4-0.7wt% Cu, ≤0.2wt% Mn, ≤0.1wt% Cr, ≤0.1wt% Zn, ≤0.1wt% Ti, ≤0.3wt% Fe, and the balance is composed of Al and unavoidable impurities.

2. A 6 series high strength aluminum alloy according to claim 1, It is characterized in that The composition of the 6-series high-strength aluminum alloy is further limited to 0.71wt% Si, 0.91wt% Mg, 0.65wt% Cu, 0.07wt% Mn, 0.012wt% Cr, 0.023wt% Zn, 0.012wt% Ti, 0.11wt% Fe, and the balance is composed of Al and unavoidable impurities.

3. A processing technology for 6 series high-strength aluminum alloy, used for preparing the 6 series high-strength aluminum alloy according to any one of claims 1-2, It is characterized in that The following steps are involved: S1. Aluminum alloy casting: S101. Melting: Al ingots, Mg ingots, Cu ingots, and Al-Si and Al-Mn master alloys are placed in a melting furnace and melted into an aluminum alloy solution according to a specified component ratio; S102. Tempering: sampling the aluminum alloy solution to quickly analyze the composition, adding metal elements to temper the aluminum alloy to a set composition range, and then slagging, refining and standing the aluminum alloy solution; S103 casting: the aluminum alloy solution processed in step S102 flows into the casting mold through the flow channel, and the aluminum alloy solution is cast through the mold to obtain a cast rod; S2. Homogenization treatment: The cast rod obtained in step S1 is heated to 540-580°C at a rate of 30-100°C / h, and kept warm for 6-24 hours. After the insulation is completed, it is cooled to below room temperature at a rate of 100-200°C / h, thereby completing the monopolar homogenization treatment; S3. Extrusion: The homogenized cast rod is subjected to aluminum extrusion. After the extruded profile comes out, it is cooled by water spray for online quenching; S4. Artificial aging treatment: The profile obtained by step S3 is heated to 170-200°C, kept at this temperature for 3-18 hours, and then cooled to room temperature by strong wind after being taken out of the furnace, thereby completing the monopolar artificial aging treatment and obtaining the 6 series high-strength aluminum alloy.

4. A processing technology for a 6 series high strength aluminum alloy according to claim 3, It is characterized in that In step S103, plate filtering may be performed in the flow channel process.

5. A processing technology for a 6 series high strength aluminum alloy according to claim 3, It is characterized in that In step S103, ≤0.2wt% of aluminum titanium boron wire can be added during the laundering process to refine the casting grains.

6. A processing technology for a 6 series high strength aluminum alloy according to claim 3, It is characterized in that In step S103, the mold plate is a hot top type or an oil-gas sliding type.

7. A processing technology for a 6 series high strength aluminum alloy according to claim 3, It is characterized in that Step S2 can also be performed by bipolar homogenization to treat the cast rods, specifically comprising the following steps: the cast rods are heated to 500-540°C at a rate of 100-200°C / h, kept warm for 2-6 hours, then heated to 550-580°C at a rate of 100-200°C / h, kept warm for 6-20 hours, and then cooled to below room temperature at a rate of 100-200°C / h to complete the bipolar homogenization treatment.

8. A processing technology for a 6 series high strength aluminum alloy according to claim 3, It is characterized in that In step S3, the working parameters of the aluminum extrusion process are: mold heating temperature is 430-480℃; ingot barrel heating temperature is 430-480℃; cast rod heating temperature is 470-550℃; extrusion rod pushing speed during extrusion is 3-6mm / s; extrusion outlet temperature is 480-560℃; the temperature of the profile after online quenching and extrusion is below 200℃; the elongation rate of the profile after aluminum extrusion is below 0.5%.

9. A processing technology for a 6 series high strength aluminum alloy according to claim 3, It is characterized in that Step S4 can also treat the profile by bipolar artificial aging treatment, which specifically includes the following steps: heating the profile to 100-130° C. and keeping it warm for 2-4 hours; then heating it to 160-180° C. and keeping it warm for 4-10 hours.

10. Use of the 6 series high strength aluminum alloy according to any one of claims 1-2 or the 6 series high strength aluminum alloy prepared by the processing technology according to any one of claims 3-9 in solar photovoltaic structural parts.

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