High-strength corrosion-resistant photovoltaic aluminum alloy frame profile and preparation method thereof

Abstract

The invention relates to the technical field of aluminum alloy materials, in particular to a high-strength corrosion-resistant photovoltaic aluminum alloy frame profile and a preparation method thereof. The aluminum alloy comprises the following components in percentage by mass: 0.65 to 0.75 percent of Si, 0.60 to 0.68 percent of Mg, 0.01 to 0.05 percent of Mn, 0.01 to 0.05 percent of Cr, less than 0.15 percent of Fe, 0.02 to 0.045 percent of Ti, 0.06 to 0.08 percent of Cu, 0.18 to 0.22 percent of Sn and the balance of Al. Due to the addition of the tin element and the precise control of the contents of main alloy elements such as magnesium and silicon, the alloy disclosed by the invention shows higher strength, toughness and fatigue resistance, so that the alloy can keep higher structural stability and durability when bearing a complex stress environment, for example, a photovoltaic frame is used for a long time in an outdoor environment. And meanwhile, the aging time required for achieving the optimal mechanical property is remarkably shortened, and the method has important significance in the aspects of improving the production efficiency, reducing the production cost, reducing the energy consumption, achieving green production and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy materials, and particularly relates to a high-strength and corrosion-resistant photovoltaic aluminum alloy frame profile and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of the photovoltaic industry, the demand and requirements for photovoltaic frames have been continuously increasing. Aluminum profiles have the characteristics of light weight, strong corrosion resistance, easy forming, high strength, easy cutting and processing, recyclability, etc., and are currently widely used in the solar energy industry. However, photovoltaic aluminum frames need to bear the weight of photovoltaic modules and the pressure of natural environments such as wind and snow, and are easily affected by corrosion. Therefore, alloys are required to have higher strength and corrosion resistance. For example, in the prior art, Chinese Patent CN107217179A provides an aluminum alloy material, and the aluminum alloy material is composed of the following elements by weight: 9.5-11.5% of Si, 0.20-0.30% of Fe, 0.03-0.07% of Cu, 0.25-0.40% of Cr, 0.25-0.40% of Sn, 0.40-0.80% of Mn, 0.05-0.09% of Zn, 0.10-0.30% of Ti, and the balance is Al. The aluminum alloy material has a relatively high elongation rate, as well as excellent yield strength and tensile strength, but its yield strength is still less than 200 MPa, and the corrosion resistance is not mentioned. Therefore, it is necessary to develop an aluminum alloy material for photovoltaic frame materials that simultaneously has high mechanical properties and corrosion resistance. Summary of the Invention

[0003] In order to solve the problems of the prior art, the present invention proposes a high-strength and corrosion-resistant photovoltaic aluminum alloy frame profile and a preparation method thereof. The specific scheme is as follows:

[0004] A high-strength and corrosion-resistant photovoltaic aluminum alloy frame profile, the mass percentage range of the aluminum alloy components is: Si 0.65-0.75%, Mg 0.60-0.68%, Mn 0.01-0.05%, Cr 0.01-0.05%, Fe < 0.15%, Ti 0.02-0.045%, Cu 0.06-0.08%, Sn: 0.18-0.22%, and the balance is Al and other inevitable impurities.

[0005] Further, the total mass of the inevitable impurities ≤ 0.1%.

[0006] Further, the tensile strength of the aluminum alloy is greater than 290 MPa, the yield strength is greater than 260 MPa, and the elongation rate is greater than 11.5%.

[0007] A preparation method of the above-mentioned aluminum alloy frame profile comprises the following steps: smelting the raw materials at 730-750°C for 4-5h according to the aluminum alloy ratio; refining and slagging, standing for 25-30min and then casting; cutting the head and tail of the round rod after casting, homogenizing and cooling, heating to 480-510°C in an extrusion rod furnace, then cutting into short rods of fixed length out of the rod furnace, and extruding at 520-540°C; after the profile is extruded, performing solid solution treatment, the solid solution temperature is 500-550°C, and the solid solution time is 1-1.5h; then cooling to below 200°C by water cooling; then performing a sandblasting process, and then aging at 180-190°C for 2-4.5h; finally performing an anodizing process to obtain the aluminum alloy photovoltaic frame profile.

[0008] Furthermore, the aging temperature is 185° C., and the aging time is no more than 2.5 hours.

[0009] The present invention adjusts the contents of main alloying elements such as silicon (Si), magnesium (Mg), manganese (Mn), chromium (Cr), iron (Fe), titanium (Ti), and copper (Cu) in the alloying elements. Mg and Si have a significant effect on improving the strength and hardness of the alloy. By accurately controlling the contents of Mg and Si, the stability of basic mechanical properties is ensured. The addition of Mn can effectively refine the grains of the alloy and reduce the formation of dendrites, thereby improving the strength and toughness of the alloy. At the same time, Mn can also improve the corrosion resistance of the alloy. Cr can form intermetallic compounds in aluminum alloys, and these compounds can hinder the nucleation and growth of recrystallization. The process has a certain strengthening effect on the alloy, which helps to improve the alloy's heat resistance and corrosion resistance. In a high temperature environment, Cr can maintain the stability of the alloy and prevent its performance from deteriorating. The addition of Cu can further improve the strength and hardness of the alloy. Cu can also form a solid solution with Al to enhance the mechanical properties of the alloy. The introduction of tin (Sn) limits its content to between 0.18% and 0.22%. The addition of Sn significantly shortens the aging time and improves the aging efficiency of the alloy. At the same time, the tin element can form solid solution strengthening, which can improve the hardness and mechanical properties of the alloy, so that the alloy can better resist deformation and fracture when subjected to external forces.

[0010] The aluminum alloy material proposed by the present invention exhibits higher strength, toughness and fatigue resistance due to the addition of tin and the precise control of the content of main alloying elements such as magnesium and silicon. This enables it to maintain higher structural stability and durability when subjected to complex stress environments, such as the long-term use of photovoltaic frames in outdoor environments. At the same time, the aging time required to achieve optimal mechanical properties is significantly shortened, which is of great significance for improving production efficiency, reducing production costs, reducing energy consumption, and achieving green production. This alloy material can not only be used in traditional fields such as photovoltaic frames, but can also be expanded to more high-end application fields such as automobile manufacturing, aerospace, and building materials. Brief Description of the Drawings

[0011] The embodiments of the present invention will be further described below with reference to the accompanying drawings, where:

[0012] Figure 1 It shows the metallographic inspection photo of the alloy in Example 2 after the grain boundary corrosion test;

[0013] Figure 2 It shows the metallographic inspection photo of the alloy in Comparative Example 1 after the grain boundary corrosion test. Detailed Embodiments

[0014] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below through specific embodiments with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0015] Example 1

[0016] A high-strength and corrosion-resistant photovoltaic frame profile aluminum alloy, the mass percentage range of the aluminum alloy components is: Si 0.65%, Mg 0.61%, Mn 0.02%, Cr 0.03%, Fe 0.10%, Ti 0.03%, Cu 0.06%, Sn: 0.18%, the balance is Al and other inevitable impurities, and the total mass percentage of the impurities does not exceed 0.1%.

[0017] The raw materials are melted at 750°C for 4 h according to the aluminum alloy ratio; refined, slag removed, and left standing for 25 min before casting; the head and tail of the cast round bar are cut off, homogenized, cooled, heated to 500°C in an extrusion rod furnace, and then cut into fixed-length short rods out of the rod furnace and extruded at 520°C; after the profile is extruded, solution treatment is carried out, the solution temperature is 530°C, and the solution time is 1 h; then it is cooled to below 200°C by water cooling; then it goes through a sandblasting process and is aged at 185°C for 4.5 h; finally, it goes through an anodic oxidation process to obtain the aluminum alloy photovoltaic frame profile. The tensile strength, yield strength, and elongation of the alloy profile at room temperature are 291 MPa, 269 MPa, and 11.7% respectively.

[0018] Example 2

[0019] A high-strength and corrosion-resistant photovoltaic frame profile aluminum alloy, the mass percentage range of the aluminum alloy components is: Si 0.65%, Mg 0.61%, Mn 0.02%, Cr 0.03%, Fe 0.10%, Ti 0.03%, Cu 0.06%, Sn: 0.18%, the balance is Al and other inevitable impurities, and the total mass percentage of the impurities does not exceed 0.1%.

[0020] The raw materials are melted at 750 °C for 4 h according to the aluminum alloy ratio; after refining, skimming the slag and standing for 25 min, casting is carried out; the head and tail of the cast round bar are cut off, homogenized and cooled, then heated to 500 °C in an extrusion bar furnace, and then cut into fixed-length short bars after leaving the bar furnace and extruded at 520 °C; after the profile is extruded, solution treatment is carried out, the solution temperature is 530 °C and the solution time is 1 h; then it is cooled to below 200 °C by water cooling; then it goes through a sandblasting process and is aged at 185 °C for 2.5 h; finally, through an anodic oxidation process, an aluminum alloy photovoltaic frame profile is obtained. The tensile strength, yield strength and elongation of this alloy profile at room temperature are 295 MPa, 273 MPa and 11.9% respectively.

[0021] Example 3

[0022] A high-strength and corrosion-resistant aluminum alloy for photovoltaic frame profiles, the mass percentage range of the aluminum alloy components is: Si 0.75%, Mg 0.68%, Mn 0.02%, Cr 0.05%, Fe 0.11%, Ti 0.04%, Cu 0.08%, Sn: 0.20%, the balance is Al and other inevitable impurities, and the total mass ratio of the impurities does not exceed 0.1%.

[0023] The raw materials are melted at 730 °C for 4 h according to the aluminum alloy ratio; after refining, skimming the slag and standing for 25 min, casting is carried out; the head and tail of the cast round bar are cut off, homogenized and cooled, then heated to 480 °C in an extrusion bar furnace, and then cut into fixed-length short bars after leaving the bar furnace and extruded at 520 °C; after the profile is extruded, solution treatment is carried out, the solution temperature is 510 °C and the solution time is 1.5 h; then it is cooled to below 200 °C by water cooling; then it goes through a sandblasting process and is aged at 185 °C for 2.5 h; finally, through an anodic oxidation process, an aluminum alloy photovoltaic frame profile is obtained. The tensile strength, yield strength and elongation of this alloy profile at room temperature are 293 MPa, 270 MPa and 11.8% respectively.

[0024] Example 4

[0025] A high-strength and corrosion-resistant aluminum alloy for photovoltaic frame profiles, the mass percentage range of the aluminum alloy components is: Si 0.7%, Mg 0.65%, Mn 0.05%, Cr 0.03%, Fe 0.13%, Ti 0.045%, Cu 0.075%, Sn: 0.22%, the balance is Al and other inevitable impurities, and the total mass ratio of the impurities does not exceed 0.1%.

[0026] The raw materials are melted at 740 °C for 5 h according to the aluminum alloy ratio; after refining, skimming and standing for 30 min, casting is carried out; the head and tail of the cast round bar are cut off, homogenized and cooled, then heated to 510 °C in an extrusion bar furnace, and then cut into fixed-length short bars after leaving the bar furnace, and extruded at 540 °C; after the profile is extruded, solution treatment is carried out, the solution temperature is 550 °C, and the solution time is 1 h; then it is cooled to below 200 °C by water cooling; then it goes through a sandblasting process and is aged at 185 °C for 2.5 h; finally, it goes through an anodizing process to obtain an aluminum alloy photovoltaic frame profile. The tensile strength, yield strength and elongation of this alloy profile at room temperature are 296 MPa, 269 MPa and 11.8% respectively.

[0027] Example 5

[0028] A high-strength and corrosion-resistant aluminum alloy for photovoltaic frame profiles, the mass percentage range of the aluminum alloy components is: Si 0.71%, Mg 0.62%, Mn 0.04%, Cr 0.02%, Fe 0.13%, Ti 0.015%, Cu 0.06%, Sn: 0.21%, and the balance is Al and other inevitable impurities, and the total mass percentage of the impurities does not exceed 0.1%.

[0029] The raw materials are melted at 750 °C for 4 h according to the aluminum alloy ratio; after refining, skimming and standing for 30 min, casting is carried out; the head and tail of the cast round bar are cut off, homogenized and cooled, then heated to 480 °C in an extrusion bar furnace, and then cut into fixed-length short bars after leaving the bar furnace, and extruded at 520 °C; after the profile is extruded, solution treatment is carried out, the solution temperature is 500 °C, and the solution time is 1 h; then it is cooled to below 200 °C by water cooling; then it goes through a sandblasting process and is aged at 185 °C for 2 h; finally, it goes through an anodizing process to obtain an aluminum alloy photovoltaic frame profile. The tensile strength, yield strength and elongation of this alloy profile at room temperature are 294 MPa, 271 MPa and 11.6% respectively.

[0030] Comparative Example 1

[0031] An aluminum alloy for photovoltaic frame profiles, the mass percentage range of the aluminum alloy components is: Si 0.65%, Mg 0.61%, Mn 0.02%, Cr 0.03%, Fe 0.10%, Ti 0.06%, Cu 0.02%, and the balance is Al and other inevitable impurities, and the total mass percentage of the impurities does not exceed 0.1%.

[0032] The raw materials were smelted at 750℃ for 4h according to the aluminum alloy ratio; refined and slag removed, and then cast after standing for 25min; the round bars after casting were cut off the head and tail, homogenized and cooled, and heated to 500℃ in the extrusion rod furnace, and then cut into short bars of fixed length out of the rod furnace and extruded at 520℃; after the profile was extruded, it was solution treated at a solution temperature of 530℃ and a solution time of 1h; then it was cooled to below 200℃ by water cooling; then it was sandblasted and aged at 185℃ for 4.5h; finally, it was anodized to obtain the aluminum alloy photovoltaic frame profile. The tensile strength, yield strength and elongation of the alloy profile at room temperature are 274MPa, 243MPa and 11.3% respectively.

[0033] From the comparison of the mechanical properties of Examples 1-5 and Comparative Example 1, it can be seen that due to the effect of alloying elements and the optimization of the organizational structure, the tensile strength, yield strength and elongation of the alloy of the present invention are improved, indicating that the alloy of the present invention can better resist deformation and fracture when subjected to tension, can better maintain the stability of its shape and size when subjected to external force, and can better adapt to various deformation requirements during processing, thereby improving its processing performance and service life.

[0034] In addition, the alloys in Examples 1-5 and Comparative Example 1 were subjected to intergranular corrosion tests according to the method described in GBT 7998-2023 Evaluation Method for Intergranular Corrosion Sensitivity of Aluminum Alloys. The test results are shown in the following table. The corroded samples were ground and polished, and then metallographic examinations were performed on Example 2 and Comparative Example 1. Figure 1-2As shown, it can be seen that there is obvious intergranular corrosion in the alloy of Comparative Example 1. The corrosion penetrates deeply along the grain boundaries, forming corrosion channels. The morphology of the corrosion area is irregular, showing relatively deep corrosion pits and corrosion gullies. The corrosion level is 3, indicating that the corrosion degree is relatively serious and has had a significant impact on the properties of the alloy. Compared with the alloy of Comparative Example 1, significantly less corrosion was observed in the metallographic picture of the alloy of Example 2, which only showed isolated pitting corrosion, that is, the corrosion was limited to small areas on the surface of the alloy and no continuous corrosion channels were formed. The corrosion level is none, indicating that the alloy of the present invention performs excellently in terms of intergranular corrosion resistance and can effectively resist the erosion of the corrosive environment. This is because in the present invention, an appropriate content of Mn element can refine the grains of the aluminum alloy, improve the microstructure of the alloy, and thus improve its corrosion resistance. Mn can also form stable compounds with Al, and these compounds can inhibit the occurrence of intergranular corrosion. Cr can also improve the toughness of the alloy and reduce the sensitivity to stress corrosion cracking, thereby improving the corrosion performance of the alloy. With the addition of an appropriate amount of Cu element, although the addition of Cu will reduce the corrosion resistance of the aluminum alloy to a certain extent, in the alloy of the present invention, the addition amount of Cu is controlled within a suitable range. Within this range, Cu can form a solid solution with Al, enhancing the mechanical properties of the alloy without having too much negative impact on the corrosion resistance. The addition of Sn element indirectly improves its corrosion performance by affecting the electrochemical properties of the alloy. The combined action of each element improves the electrochemical properties and microstructure of the alloy, making the alloy of the present invention less likely to undergo electrochemical reactions in humid and high-temperature environments, thereby reducing the risk of intergranular corrosion.

[0035] Table 1 Results of intergranular corrosion tests for examples and comparative examples

[0036] Serial number Maximum depth of intergranular corrosion / D μm Corrosion level Comparative example 1 Regional distribution 54.37 Level 3 Example 1 Pitting corrosion —— Example 2 Pitting corrosion —— Example 3 Pitting corrosion —— Example 4 Pitting corrosion —— Example 5 Pitting corrosion ——

[0037] In addition, it can be seen from the comparison between Example 1 and Example 2 that, under the same alloy composition, the sample in Example 2 experienced a shorter aging time but had better mechanical properties. In actual production, energy consumption can be saved quite significantly, specifically about 40% of the energy consumption can be saved. This is mainly because the solubility of Sn element in aluminum alloy is relatively low, but it has a large binding ability with vacancies and can form solute atom-vacancy pairs. This binding helps to inhibit the aggregation of vacancies and solute atoms during natural aging, thus slowing down the nucleation and growth process of the precipitation phase. During the aging treatment stage, due to the presence of Sn element, the formation of the precipitation phase requires a higher activation energy or a longer incubation period. Therefore, within a relatively short aging time (such as 2.5 h), the precipitation phase is still in the nucleation and initial growth stage and has not undergone obvious coarsening; at the same time, the addition of Sn element may change the morphology and distribution of the precipitation phase. The fine precipitation phases act as obstacles, increasing the resistance to dislocation movement, thereby improving the yield strength and tensile strength of the alloy. That is, within a relatively short aging time, since the precipitation phases have not fully grown, they remain in a finer and more dispersed state, which is more conducive to the improvement of mechanical properties. In addition, Sn element may further increase the strength of the alloy through solid solution strengthening. Solid solution strengthening means that the disordered distribution of solute atoms in the matrix causes lattice distortion of the matrix, thereby increasing the resistance to dislocation movement. Although the addition of Sn element may increase the hardness of the alloy to a certain extent, in this example, due to the precipitation phases remaining fine and dispersed, they have little impact on the plastic deformation ability of the alloy. In fact, the fine precipitation phases may, to a certain extent, improve the strain accommodation ability of the alloy, enabling the alloy to absorb more energy during plastic deformation without fracture, which helps to maintain a relatively high elongation rate.

[0038] Some exemplary embodiments of the present invention are described above. It can be understood that the above embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention. The features in these embodiments can be recombined in a suitable manner, and the obtained solutions are still within the protection scope required by the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without creative efforts, that is, all modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this application, fall within the protection scope required by the present invention.

Claims

1. A high-strength and corrosion-resistant photovoltaic aluminum alloy frame profile, characterized in that: The mass percentage range of the aluminum alloy components is: Si 0.65-0.75%, Mg 0.60-0.68%, Mn 0.01-0.05%, Cr 0.01-0.05%, Fe < 0.15%, Ti 0.02-0.045%, Cu 0.06-0.08%, Sn: 0.18-0.22%, and the balance is Al and other inevitable impurities.

2. The high-strength and corrosion-resistant photovoltaic aluminum alloy frame profile according to claim 1 is characterized in that: The total mass of the unavoidable impurities is ≤0.1%.

3. The high-strength and corrosion-resistant photovoltaic aluminum alloy frame profile according to claim 1 is characterized in that: The aluminum alloy has a tensile strength greater than 290 MPa, a yield strength greater than 260 MPa, and an elongation greater than 11.5%.

4. A method for preparing the aluminum alloy frame profile according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: smelting the raw materials at 730-750°C for 4-5h according to the aluminum alloy ratio; refining, slagging, standing for 25-30min and then casting; cutting the head and tail of the round rod after casting, homogenizing, cooling, heating to 480-510°C in an extrusion rod furnace, then cutting into short rods of fixed length out of the rod furnace, and extruding at 520-540°C; after the profile is extruded, performing solid solution treatment, the solid solution temperature is 500-550°C, and the solid solution time is 1-1.5h; then cooling to below 200°C through water cooling; then performing a sandblasting process, and then aging at 180-190°C for 2-4.5h; and finally performing an anodizing process to obtain the aluminum alloy photovoltaic frame profile.

5. The method for preparing the aluminum alloy according to claim 4, characterized in that: The aging temperature is 185° C., and the aging time is no more than 2.5 hours.

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