High-strength weldable 6xxx series aluminum alloy and preparation method of extruded material of high-strength weldable 6xxx series aluminum alloy

Abstract

The invention relates to a preparation method of a high-strength weldable 6xxx series aluminum alloy and an extruded material thereof, which comprises the following steps of: (1) preparing a 6xxx series aluminum alloy round cast ingot by adopting a direct water cooling semi-continuous casting (DC casting for short) mode, and the alloy components of the 6xxx series aluminum alloy round cast ingot comprise 0.90-1.45% of Mg, 1.00-1.55% of Si, 0.40-0.80% of Cu, 0.30-0.80% of Zn, 0.08-0.15% of Zr, less than or equal to 0.50% of Mn, less than or equal to 0.35% of Cr, less than or equal to 0.60% of Fe, less than or equal to 0.30% of Ti and the balance of Al; (2) homogenization treatment is conducted, specifically, the 6xxx series aluminum alloy cast ingot is subjected to homogenization treatment at 540-555 DEG C for 4-8 h, and then air cooling is conducted; (3) heating is conducted, specifically, the 6xxx series aluminum alloy cast ingot obtained after homogenization treatment is heated to 440-460 DEG C; (4) extrusion is conducted, specifically, the 6xxx series aluminum alloy cast ingot obtained after heat preservation is subjected to hot extrusion, the extrusion ratio is 10-15, the extrusion speed is 1.0-1.5 mm / s, the temperature of an extrusion container is 400-430 DEG C, the extrusion temperature is 440-460 DEG C, and water cooling or air cooling is conducted at an outlet; (5) solution treatment is conducted, specifically, the 6xxx series aluminum alloy extruded profile / bar is heated to 540-555 DEG C, heat preservation is conducted for 15-90 min, and then water quenching is conducted; (6) aging treatment: loading the extruded profile / bar subjected to solution treatment into an aging furnace, heating to 165-175 DEG C, keeping the temperature for 8-14 hours, discharging from the furnace, and cooling in air; according to the method, the content of alloy elements in the 6xxx series aluminum alloy is optimized and regulated through component design, so that main alloy elements and trace alloy elements have the optimal proportion. After an alloy cast ingot is subjected to homogenization, extrusion, off-line solid solution water quenching and artificial aging treatment, the strength of the alloy cast ingot exceeds 420 MPa, the fusion welding coefficient reaches 0.7-0.8, the fatigue strength exceeds 160 MPa, and meanwhile the alloy cast ingot has good plasticity and corrosion resistance.

Description

Technical field:

[0001] The present invention belongs to the technical field of aluminum alloys, and in particular relates to a preparation method of a 6xxx series aluminum alloy with high strength and excellent fusion welding performance and an extruded material thereof. Background technology:

[0002] 6xxx series aluminum alloys are widely used in the manufacture of key load-bearing parts such as high-speed train side beams, pillow blocks, traction beams, reinforcement plates, and automobile body covers and floor panels due to their high specific strength, excellent weldability, corrosion resistance, and good processing and forming properties.

[0003] The content and ratio of alloying elements are an important factor in determining the performance of aluminum alloys. The common industrialized 6xxx aluminum alloys at home and abroad mainly consist of Mg: 0.20-1.40%, Si: 0.20-1.80%, Cu: 0.10-0.90%, Zn≤0.65%, Zr: 0.01-0.35%, Mn≤1.10%, Cr≤0.40%, Fe≤0.50%, Ti≤0.20%, and the balance is Al. In the production process of 6xxx aluminum alloys, the ratio of the three main alloying elements Mg, Si, and Cu is difficult to control. When the Mg content is high, the corrosion resistance of the alloy is good, but the strength and forming properties are low; when the Si content is high, although the alloy strength is high, the forming and welding properties are low. Increasing the Cu content will form precipitation phase particles with more significant matrix strengthening effect, which can significantly improve the alloy strength, but will seriously deteriorate the alloy's weldability. Therefore, the comprehensive performance of the industrialized 6xxx series aluminum alloys disclosed at home and abroad cannot meet the requirements of the load-bearing parts of high-speed train bodies with a speed of more than 450km / h. The tensile strength and yield strength of 6016 aluminum plate (Al-0.45Mg-1.11Si-0.12Mn-0.11Ti-0.1Cu) are 334MPa and 280MPa respectively, but its fatigue performance is poor, only 73MPa; 6063-T6 aluminum plate (Al-0.557Mg-0.429Si-0.020Zn-0.009Mn) has a medium content of Mg and Si, and its tensile strength and yield strength are The strength is also medium, 245MPa and 224MPa respectively; 6082-T6 aluminum plate (Al-0.40Si-4.20Mg-0.25Zn-0.10Cu-0.60Mn-0.10Cr-0.40Fe-0.15Ti) has a higher content of Mg, and its fatigue strength is higher, 146MPa, and the welding coefficient can reach 0.7, but its tensile strength and yield strength are only 188MPa and 85MPa. Therefore, how to optimize the ratio of the main alloying elements and the content of trace elements in 6xxx series aluminum alloys to develop a new 6xxx series aluminum alloy with a strength of more than 420MPa, a fusion welding joint coefficient of more than 0.7, a fatigue strength of more than 160MPa, and at the same time ensure that it has good plasticity, fatigue performance and corrosion resistance, and its corresponding preparation and processing technology has strong innovation and practical engineering application value. Summary of the invention:

[0004] The purpose of the present invention is to provide a new 6xxx series aluminum alloy composition with a strength exceeding 420MPa, a fusion welding joint coefficient greater than 0.7, and a fatigue strength exceeding 160MPa, and a corresponding preparation method for its extruded material. The content of alloying elements in the 6xxx series aluminum alloy is controlled by component design and optimization, so that the main alloying elements and trace alloying elements have an optimal ratio. After the alloy ingot is homogenized, extruded, and subjected to offline solution water quenching and artificial aging treatment, its strength exceeds 420MPa, the fusion welding coefficient reaches 0.7-0.8, and the fatigue strength exceeds 160MPa, and it has good plasticity and corrosion resistance.

[0005] To achieve the above objectives, the present invention adopts the following technical solutions:

[0006] A method for preparing a high-strength weldable 6xxx series aluminum alloy comprises the following steps:

[0007] (1) Ingot preparation: Direct Chill semi-continuous Casting (DC casting) is used to prepare 6xxx series aluminum alloy round ingots, and the alloy composition range is Mg: 0.90-1.45%, Si: 1.00-1.55%, Cu: 0.40-0.80%, Zn: 0.30-0.80%, Zr: 0.08-0.15%, Mn≤0.50%, Cr≤0.35%, Fe≤0.60%, Ti≤0.30, and the balance is Al.

[0008] (2) Homogenization treatment: subject the 6xxx series aluminum alloy ingot to homogenization treatment at 540-555°C for 4-8 hours and then air-cooling;

[0009] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 440-460° C.;

[0010] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded, with an extrusion ratio of 10 to 15, an extrusion speed of 1.0 to 1.5 mm / s, an extrusion barrel temperature of 400 to 430°C, an extrusion temperature of 440 to 460°C, and water cooling or air cooling at the outlet;

[0011] (5) Solution treatment: Heat the 6xxx series aluminum alloy extruded profile / bar to 540-555°C, keep it at this temperature for 15-90 min, and then quench it in water;

[0012] (6) Aging treatment: The extruded profiles / bars after solution treatment are placed in an aging furnace, heated to 165-175°C for 8-14 hours, and air-cooled after being taken out of the furnace;

[0013] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0014] (8) Conducting tensile tests: Conducting tensile tests on extruded profiles / bars of 6xxx aluminum alloys with different compositions after solution aging treatment and extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0015] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0016] (10) Determination of fatigue strength: Extruded profiles / bars of 6xxx aluminum alloys with different compositions after solid solution aging are subjected to fatigue tests in accordance with GB / T 3075-2021 “Axial force control method for fatigue testing of metallic materials” to determine their fatigue limits;

[0017] (11) Exfoliation corrosion test: Exfoliation corrosion test was performed on extruded profiles / bars of 6xxx series aluminum alloys with different compositions after solid solution aging in accordance with GB / T 22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0018] Beneficial effects of the present invention:

[0019] (1) The method of the present invention significantly improves the strength and welding performance of 6xxx series aluminum alloys by regulating the content of various alloying elements in the alloys.

[0020] (2) The process of the present invention can be implemented on the existing aluminum alloy plate production line without changing the existing tooling and increasing the investment in equipment and process. The operation is simple, convenient and feasible.

[0021] Specific implementation:

[0022] The present invention is further described in detail below in conjunction with embodiments.

[0023] Example 1

[0024] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.40%, Si: 1.40%, Cu: 0.45%, Zn: 0.36%, Zr: 0.12%, Mn: 0.40%, Cr: 0.35%, Fe: 0.60%, Ti: 0.25%, and the balance being Al.

[0025] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 540°C for 6 h and then air-cooled;

[0026] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 445° C.

[0027] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 13, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 410°C, an extrusion temperature of 445°C, and water cooling or air cooling at the outlet;

[0028] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 550°C, keep it at this temperature for 30 min, and then quench it in water;

[0029] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 12 hours, and air-cooled after being taken out of the furnace;

[0030] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0031] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0032] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0033] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0034] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0035] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0036] Comparative Example 1

[0037] (1) Ingot preparation: A 6061 aluminum alloy round ingot was prepared by direct water-cooled semi-continuous casting, and the composition and mass percentage thereof were as follows: Mg: 0.86%, Si: 0.51%, Cu: 0.28%, Zn: 0.01%, Cr: 0.06%, Fe: 0.15%, Ti: 0.03%, and the balance was Al.

[0038] (2) Homogenization treatment: The 6061 aluminum alloy ingot was subjected to homogenization treatment at 540°C for 6 h and then air-cooled;

[0039] (3) Heating: heating the 6061 aluminum alloy ingot after homogenization treatment to 445° C.

[0040] (4) Extrusion: The 6061 aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 13, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 410°C, an extrusion temperature of 445°C, and water cooling or air cooling at the outlet;

[0041] (5) Solution treatment: heat the 6061 aluminum alloy extrusion profile to 550 °C, keep it at this temperature for 30 min, and then quench it in water;

[0042] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 12 hours, and air-cooled after being taken out of the furnace;

[0043] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0044] (8) Conducting tensile test: Conducting tensile test on the extruded profiles after solution aging treatment of 6061 aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile test of deformed aluminum, magnesium and their alloy products”;

[0045] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0046] (10) Determination of fatigue strength: The extruded profiles of 6061 aluminum alloy after solid solution aging were subjected to fatigue tests according to GB / T 3075-2021 “Axial force control method for fatigue testing of metallic materials” to determine their fatigue limit;

[0047] (11) Exfoliation corrosion test: The extruded profiles of 6061 aluminum alloy after solid solution aging were subjected to exfoliation corrosion test in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0048] The 6061 aluminum alloy prepared in this comparative example was subjected to tensile, fatigue and welding tests to determine its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0049] Example 2

[0050] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.45%, Si: 1.55%, Cu: 0.50%, Zn: 0.37%, Zr: 0.14%, Mn: 0.35%, Cr: 0.15%, Fe: 0.33%, Ti: 0.16%, and the balance being Al.

[0051] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 555°C for 4 h and then air-cooled;

[0052] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0053] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 11, an extrusion speed of 1.2 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0054] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 540°C, keep it at this temperature for 90 min, and then quench it in water;

[0055] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0056] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0057] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0058] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0059] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0060] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0061] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0062] Example 3

[0063] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.20%, Si: 1.50%, Cu: 0.50%, Zn: 0.30%, Zr: 0.10%, Mn: 0.15%, Cr: 0.28%, Fe: 0.52%, Ti: 0.16%, and the balance being Al.

[0064] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingot at 550°C for 5 h followed by air cooling;

[0065] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 460° C.

[0066] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 15, an extrusion speed of 1.5 mm / s, an extrusion barrel temperature of 400°C, an extrusion temperature of 460°C, and water cooling or air cooling at the outlet;

[0067] (5) Solution treatment: heat the 6xxx aluminum alloy extrusion profile to 555°C, keep it at this temperature for 15 min, and then quench it in water;

[0068] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0069] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0070] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0071] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0072] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0073] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0074] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0075] Example 4

[0076] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.00%, Si: 1.40%, Cu: 0.57%, Zn: 0.47%, Zr: 0.08%, Mn: 0.27%, Cr: 0.16%, Fe: 0.18%, Ti: 0.17%, and the balance being Al.

[0077] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 545°C for 7 h and then air-cooled;

[0078] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 440° C.

[0079] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is subjected to hot extrusion, with an extrusion ratio of 10, an extrusion speed of 1.0 mm / s, an extrusion barrel temperature of 430°C, an extrusion temperature of 440°C, and water cooling or air cooling at the outlet;

[0080] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 45 min, and then quench it in water;

[0081] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0082] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0083] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0084] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0085] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0086] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0087] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0088] Example 5

[0089] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.17%, Si: 1.00%, Cu: 0.75%, Zn: 0.70%, Zr: 0.12%, Mn: 0.45%, Cr: 0.32%, Fe: 0.48%, Ti: 0.16%, and the balance being Al.

[0090] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 555°C for 8 h and then air-cooled;

[0091] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 455° C.

[0092] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 14, an extrusion speed of 1.5 mm / s, an extrusion barrel temperature of 430°C, an extrusion temperature of 455°C, and water cooling or air cooling at the outlet;

[0093] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 45 min, and then quench it in water;

[0094] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0095] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0096] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0097] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0098] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0099] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0100] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0101] Example 6

[0102] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.26%, Si: 1.37%, Cu: 0.65%, Zn: 0.50%, Zr: 0.14%, Mn: 0.26%, Cr: 0.20%, Fe: 0.43%, Ti: 0.22%, and the balance being Al.

[0103] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 545°C for 7 h and then air-cooled;

[0104] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0105] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 12, an extrusion speed of 1.1 mm / s, an extrusion barrel temperature of 430°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0106] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 550°C, keep it at this temperature for 30 min, and then quench it in water;

[0107] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 12 hours, and air-cooled after being taken out of the furnace;

[0108] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0109] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0110] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0111] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0112] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0113] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0114] Example 7

[0115] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 0.90%, Si: 1.30%, Cu: 0.73%, Zn: 0.65%, Zr: 0.15%, Mn: 0.18%, Cr: 0.31%, Fe: 0.55%, Ti: 0.08%, and the balance being Al.

[0116] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 540°C for 8 h and then air-cooled;

[0117] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0118] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 14, an extrusion speed of 1.4 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0119] (5) Solution treatment: heat the 6xxx series aluminum alloy extruded bar to 555°C, keep it at this temperature for 15 min, and then quench it in water;

[0120] (6) Aging treatment: The extruded bars after solution treatment are placed in an aging furnace, heated to 175°C for 8 hours, and air-cooled after being taken out of the furnace;

[0121] (7) Conducting a tensile test: Conducting a tensile test on the extruded bars of 6xxx series aluminum alloy after solid solution aging treatment in accordance with GB / T16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0122] (8) Determination of fatigue strength: The extruded bars of 6xxx aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0123] (9) Exfoliation corrosion test: Exfoliation corrosion test is performed on extruded bars of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0124] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile and fatigue tests to measure its strength, elongation and fatigue limit. The specific performance indicators are shown in Table 1.

[0125] Example 8

[0126] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.45%, Si: 1.02%, Cu: 0.77%, Zn: 0.62%, Zr: 0.15%, Mn: 0.33%, Cr: 0.29%, Fe: 0.55%, Ti: 0.09%, and the balance being Al.

[0127] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 545°C for 8 h and then air-cooled;

[0128] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 445° C.

[0129] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 11, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 445°C, and water cooling or air cooling at the outlet;

[0130] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 30 min, and then quench it in water;

[0131] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0132] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0133] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0134] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0135] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0136] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0137] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0138] Example 9

[0139] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 0.93%, Si: 1.00%, Cu: 0.78%, Zn: 0.40%, Zr: 0.09%, Mn: 0.33%, Cr: 0.12%, Fe: 0.45%, Ti: 0.19%, and the balance being Al.

[0140] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingot at 550°C for 7 h followed by air cooling;

[0141] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 455° C.

[0142] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 15, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 455°C, and water cooling or air cooling at the outlet;

[0143] (5) Solution treatment: heat the 6xxx aluminum alloy extrusion profile to 550°C, keep it at this temperature for 15 min, and then quench it in water;

[0144] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0145] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0146] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0147] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0148] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0149] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0150] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0151] Example 10

[0152] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.40%, Si: 1.32%, Cu: 0.70%, Zn: 0.53%, Zr: 0.14%, Mn: 0.38%, Cr: 0.32%, Fe: 0.46%, Ti: 0.25%, and the balance being Al.

[0153] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 540°C for 8 h and then air-cooled;

[0154] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 445° C.

[0155] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 13, an extrusion speed of 1.2 mm / s, an extrusion barrel temperature of 425°C, an extrusion temperature of 445°C, and water cooling or air cooling at the outlet;

[0156] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 30 min, and then quench it in water;

[0157] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0158] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0159] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0160] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0161] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0162] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0163] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0164] Embodiment 11

[0165] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.30%, Si: 1.03%, Cu: 0.68%, Zn: 0.63%, Zr: 0.09%, Mn: 0.26%, Cr: 0.32%, Fe: 0.39%, Ti: 0.26%, and the balance being Al.

[0166] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 555°C for 6 h and then air-cooled;

[0167] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0168] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 14, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 410°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0169] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 540°C, keep it at this temperature for 90 min, and then quench it in water;

[0170] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 12 hours, and air-cooled after being taken out of the furnace;

[0171] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0172] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0173] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0174] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0175] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0176] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0177] Example 12

[0178] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.00%, Si: 1.00%, Cu: 0.70%, Zn: 0.77%, Zr: 0.11%, Mn: 0.41%, Cr: 0.24%, Fe: 0.39%, Ti: 0.06%, and the balance being Al.

[0179] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 545°C for 6 h and then air-cooled;

[0180] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 460° C.

[0181] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is subjected to hot extrusion, with an extrusion ratio of 10, an extrusion speed of 1.2 mm / s, an extrusion barrel temperature of 430°C, an extrusion temperature of 460°C, and water cooling or air cooling at the outlet;

[0182] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 45 min, and then quench it in water;

[0183] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0184] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0185] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0186] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0187] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0188] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0189] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0190] Embodiment 13

[0191] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 0.90%, Si: 1.00%, Cu: 0.40%, Zn: 0.30%, Zr: 0.08%, Mn: 0.32%, Cr: 0.11%, Fe: 0.29%, Ti: 0.25%, and the balance being Al.

[0192] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingot at 550°C for 8 h followed by air cooling;

[0193] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0194] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 13, an extrusion speed of 1.4 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0195] (5) Solution treatment: heat the 6xxx series aluminum alloy extruded bar to 550°C, keep it at this temperature for 30 min, and then quench it in water;

[0196] (6) Aging treatment: The extruded bars after solution treatment are placed in an aging furnace, heated to 175°C for 8 hours, and air-cooled after being taken out of the furnace;

[0197] (7) Conducting a tensile test: Conducting a tensile test on the extruded bars of 6xxx series aluminum alloy after solid solution aging treatment in accordance with GB / T16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0198] (8) Determination of fatigue strength: The extruded bars of 6xxx aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0199] (9) Exfoliation corrosion test: Exfoliation corrosion test is performed on extruded bars of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0200] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile and fatigue tests to measure its strength, elongation and fatigue limit. The specific performance indicators are shown in Table 1.

[0201] Embodiment 14

[0202] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.20%, Si: 1.30%, Cu: 0.55%, Zn: 0.42%, Zr: 0.12%, Mn: 0.26%, Cr: 0.24%, Fe: 0.37%, Ti: 0.12%, and the balance being Al.

[0203] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 545°C for 6 h and then air-cooled;

[0204] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0205] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is subjected to hot extrusion, with an extrusion ratio of 13, an extrusion speed of 1.1 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0206] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 30 min, and then quench it in water;

[0207] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 12 hours, and air-cooled after being taken out of the furnace;

[0208] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0209] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0210] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0211] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0212] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0213] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0214] Embodiment 15

[0215] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.05%, Si: 1.10%, Cu: 0.80%, Zn: 0.70%, Zr: 0.09%, Mn: 0.23%, Cr: 0.15%, Fe: 0.52%, Ti: 0.22%, and the balance being Al.

[0216] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingot at 550°C for 7 h followed by air cooling;

[0217] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 445° C.

[0218] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 14, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 410°C, an extrusion temperature of 445°C, and water cooling or air cooling at the outlet;

[0219] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 540°C, keep it at this temperature for 90 min, and then quench it in water;

[0220] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0221] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0222] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0223] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0224] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0225] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0226] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0227] Example 16

[0228] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.32%, Si: 1.25%, Cu: 0.60%, Zn: 0.61%, Zr: 0.12%, Mn: 0.43%, Cr: 0.13%, Fe: 0.26%, Ti: 0.12%, and the balance being Al.

[0229] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 545°C for 6 h and then air-cooled;

[0230] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 455° C.

[0231] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 12, an extrusion speed of 1.4 mm / s, an extrusion barrel temperature of 435°C, an extrusion temperature of 455°C, and water cooling or air cooling at the outlet;

[0232] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 45 min, and then quench it in water;

[0233] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 12 hours, and air-cooled after being taken out of the furnace;

[0234] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0235] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0236] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0237] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0238] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0239] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0240] Embodiment 17

[0241] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.19%, Si: 1.19%, Cu: 0.72%, Zn: 0.69%, Zr: 0.12%, Mn: 0.44%, Cr: 0.30%, Fe: 0.54%, Ti: 0.22%, and the balance being Al.

[0242] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingot at 550°C for 8 h followed by air cooling;

[0243] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0244] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is subjected to hot extrusion, with an extrusion ratio of 13, an extrusion speed of 1.1 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0245] (5) Solution treatment: heat the 6xxx aluminum alloy extrusion profile to 555°C, keep it at this temperature for 15 min, and then quench it in water;

[0246] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 12 hours, and air-cooled after being taken out of the furnace;

[0247] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0248] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0249] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0250] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0251] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0252] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0253] Embodiment 18

[0254] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 0.97%, Si: 1.00%, Cu: 0.62%, Zn: 0.75%, Zr: 0.10%, Mn: 0.32%, Cr: 0.16%, Fe: 0.49%, Ti: 0.26%, and the balance being Al.

[0255] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 540°C for 8 h and then air-cooled;

[0256] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 445° C.

[0257] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 11, an extrusion speed of 1.5 mm / s, an extrusion barrel temperature of 410°C, an extrusion temperature of 445°C, and water cooling or air cooling at the outlet;

[0258] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 550°C, keep it at this temperature for 45 min, and then quench it in water;

[0259] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0260] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0261] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0262] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0263] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0264] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0265] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0266] Embodiment 19

[0267] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.45%, Si: 1.32%, Cu: 0.77%, Zn: 0.50%, Zr: 0.10%, Mn: 0.32%, Cr: 0.16%, Fe: 0.28%, Ti: 0.09%, and the balance being Al.

[0268] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 555°C for 6 h and then air-cooled;

[0269] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 440° C.

[0270] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 10, an extrusion speed of 1.5 mm / s, an extrusion barrel temperature of 430°C, an extrusion temperature of 440°C, and water cooling or air cooling at the outlet;

[0271] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 30 min, and then quench it in water;

[0272] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0273] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0274] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0275] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0276] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0277] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0278] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0279] Embodiment 20

[0280] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.15%, Si: 0.98%, Cu: 0.77%, Zn: 0.76%, Zr: 0.11%, Mn: 0.29%, Cr: 0.16%, Fe: 0.44%, Ti: 0.16%, and the balance being Al.

[0281] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingot at 550°C for 7 h followed by air cooling;

[0282] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0283] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 12, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0284] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 30 min, and then quench it in water;

[0285] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0286] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0287] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0288] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0289] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0290] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0291] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0292] Embodiment 21

[0293] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.20%, Si: 1.45%, Cu: 0.50%, Zn: 0.35%, Zr: 0.09%, Mn: 0.20%, Cr: 0.25%, Fe: 0.57%, Ti: 0.12%, and the balance being Al.

[0294] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingot at 550°C for 5 h followed by air cooling;

[0295] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 455° C.

[0296] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 14, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 455°C, and water cooling or air cooling at the outlet;

[0297] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 550°C, keep it at this temperature for 45 min, and then quench it in water;

[0298] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 12 hours, and air-cooled after being taken out of the furnace;

[0299] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0300] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0301] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0302] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0303] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0304] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0305] Embodiment 22

[0306] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 0.95%, Si: 1.15%, Cu: 0.76%, Zn: 0.72%, Zr: 0.12%, Mn: 0.25%, Cr: 0.19%, Fe: 0.49%, Ti: 0.26%, and the balance being Al.

[0307] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 545°C for 8 h and then air-cooled;

[0308] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 455° C.

[0309] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 13, an extrusion speed of 1.4 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 455°C, and water cooling or air cooling at the outlet;

[0310] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 30 min, and then quench it in water;

[0311] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0312] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0313] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0314] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0315] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0316] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0317] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0318] Embodiment 23

[0319] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.45%, Si: 1.40%, Cu: 0.43%, Zn: 0.42%, Zr: 0.15%, Mn: 0.42%, Cr: 0.26%, Fe: 0.26%, Ti: 0.27%, and the balance being Al.

[0320] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 555°C for 4 h and then air-cooled;

[0321] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0322] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 13, an extrusion speed of 1.2 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0323] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 540°C, keep it at this temperature for 90 min, and then quench it in water;

[0324] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0325] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0326] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0327] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0328] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0329] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0330] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0331] Embodiment 24

[0332] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.13%, Si: 1.10%, Cu: 0.60%, Zn: 0.57%, Zr: 0.10%, Mn: 0.21%, Cr: 0.13%, Fe: 0.33%, Ti: 0.30%, and the balance being Al.

[0333] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 540°C for 8 h and then air-cooled;

[0334] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 455° C.

[0335] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 14, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 410°C, an extrusion temperature of 455°C, and water cooling or air cooling at the outlet;

[0336] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 540°C, keep it at this temperature for 90 min, and then quench it in water;

[0337] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0338] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0339] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0340] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0341] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0342] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0343] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0344] Embodiment 25

[0345] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.40%, Si: 1.40%, Cu: 0.45%, Zn: 0.36%, Zr: 0.12%, Mn: 0.40%, Cr: 0.35%, Fe: 0.60%, Ti: 0.25%, and the balance being Al.

[0346] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 555°C for 4 h and then air-cooled;

[0347] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 440° C.

[0348] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 15, an extrusion speed of 1.4 mm / s, an extrusion barrel temperature of 430°C, an extrusion temperature of 440°C, and water cooling or air cooling at the outlet;

[0349] (5) Solution treatment: heat the 6xxx series aluminum alloy extruded bar to 555°C, keep it at this temperature for 15 min, and then quench it in water;

[0350] (6) Aging treatment: The extruded bars after solution treatment are placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0351] (7) Conducting a tensile test: Conducting a tensile test on the extruded bars of 6xxx series aluminum alloy after solid solution aging treatment in accordance with GB / T16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0352] (8) Determination of fatigue strength: The extruded bars of 6xxx aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0353] (9) Exfoliation corrosion test: Exfoliation corrosion test is performed on extruded bars of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0354] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile and fatigue tests to measure its strength, elongation and fatigue limit. The specific performance indicators are shown in Table 1.

[0355] Embodiment 26

[0356] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.40%, Si: 1.20%, Cu: 0.60%, Zn: 0.40%, Zr: 0.08%, Mn: 0.12%, Cr: 0.22%, Fe: 0.50%, Ti: 0.15%, and the balance being Al.

[0357] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 540°C for 8 h and then air-cooled;

[0358] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 440° C.

[0359] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 15, an extrusion speed of 1.5 mm / s, an extrusion barrel temperature of 430°C, an extrusion temperature of 440°C, and water cooling or air cooling at the outlet;

[0360] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 45 min, and then quench it in water;

[0361] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 12 hours, and air-cooled after being taken out of the furnace;

[0362] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0363] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0364] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0365] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0366] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0367] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0368] Embodiment 27

[0369] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.15%, Si: 1.15%, Cu: 0.65%, Zn: 0.60%, Zr: 0.13%, Mn: 0.44%, Cr: 0.27%, Fe: 0.42%, Ti: 0.13%, and the balance being Al.

[0370] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 545°C for 7 h and then air-cooled;

[0371] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 455° C.

[0372] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 14, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 455°C, and water cooling or air cooling at the outlet;

[0373] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 550°C, keep it at this temperature for 30 min, and then quench it in water;

[0374] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0375] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0376] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0377] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0378] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0379] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0380] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0381] Embodiment 28

[0382] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.35%, Si: 1.40%, Cu: 0.40%, Zn: 0.38%, Zr: 0.13%, Mn: 0.50%, Cr: 0.31%, Fe: 0.33%, Ti: 0.22%, and the balance being Al.

[0383] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingot at 550°C for 7 h followed by air cooling;

[0384] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 445° C.

[0385] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 14, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 445°C, and water cooling or air cooling at the outlet;

[0386] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 550°C, keep it at this temperature for 30 min, and then quench it in water;

[0387] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0388] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0389] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0390] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0391] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0392] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0393] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0394] Embodiment 29

[0395] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.05%, Si: 1.30%, Cu: 0.63%, Zn: 0.45%, Zr: 0.10%, Mn: 0.48%, Cr: 0.22%, Fe: 0.35%, Ti: 0.16%, and the balance being Al.

[0396] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 555°C for 4 h and then air-cooled;

[0397] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0398] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 15, an extrusion speed of 1.2 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0399] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 540°C, keep it at this temperature for 90 min, and then quench it in water;

[0400] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0401] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0402] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0403] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0404] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0405] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0406] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0407] Embodiment 30

[0408] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.40%, Si: 1.50%, Cu: 0.40%, Zn: 0.47%, Zr: 0.11%, Mn: 0.38%, Cr: 0.16%, Fe: 0.25%, Ti: 0.30%, and the balance being Al.

[0409] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 540°C for 7 h and then air-cooled;

[0410] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0411] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is subjected to hot extrusion, with an extrusion ratio of 13, an extrusion speed of 1.1 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0412] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 45 min, and then quench it in water;

[0413] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0414] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0415] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0416] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0417] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0418] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0419] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0420] Embodiment 31

[0421] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 0.90%, Si: 1.05%, Cu: 0.74%, Zn: 0.80%, Zr: 0.10%, Mn: 0.26%, Cr: 0.26%, Fe: 0.41%, Ti: 0.26%, and the balance being Al.

[0422] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingot at 550°C for 6 h followed by air cooling;

[0423] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 455° C.

[0424] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 13, an extrusion speed of 1.0 mm / s, an extrusion barrel temperature of 400°C, an extrusion temperature of 455°C, and water cooling or air cooling at the outlet;

[0425] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 45 min, and then quench it in water;

[0426] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 10 hours, and air-cooled after being taken out of the furnace;

[0427] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0428] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0429] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0430] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0431] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0432] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0433] Embodiment 32

[0434] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 0.90%, Si: 1.30%, Cu: 0.73%, Zn: 0.65%, Zr: 0.15%, Mn: 0.18%, Cr: 0.31%, Fe: 0.55%, Ti: 0.08%, and the balance being Al.

[0435] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 540°C for 7 h and then air-cooled;

[0436] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 455° C.

[0437] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 10, an extrusion speed of 1.4 mm / s, an extrusion barrel temperature of 430°C, an extrusion temperature of 455°C, and water cooling or air cooling at the outlet;

[0438] (5) Solution treatment: heat the 6xxx aluminum alloy extrusion profile to 550°C, keep it at this temperature for 15 min, and then quench it in water;

[0439] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 10 hours, and air-cooled after being taken out of the furnace;

[0440] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0441] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0442] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0443] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0444] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0445] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0446] Embodiment 33

[0447] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.45%, Si: 1.50%, Cu: 0.50%, Zn: 0.60%, Zr: 0.09%, Mn: 0.42%, Cr: 0.17%, Fe: 0.33%, Ti: 0.13%, and the balance being Al.

[0448] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 545°C for 7 h and then air-cooled;

[0449] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 440° C.

[0450] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is subjected to hot extrusion, with an extrusion ratio of 12, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 410°C, an extrusion temperature of 440°C, and water cooling or air cooling at the outlet;

[0451] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 30 min, and then quench it in water;

[0452] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0453] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0454] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0455] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0456] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0457] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0458] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0459] Embodiment 34

[0460] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.33%, Si: 1.50%, Cu: 0.69%, Zn: 0.31%, Zr: 0.10%, Mn: 0.29%, Cr: 0.32%, Fe: 0.46%, Ti: 0.19%, and the balance being Al.

[0461] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 555°C for 6 h and then air-cooled;

[0462] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 445° C.

[0463] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is subjected to hot extrusion, with an extrusion ratio of 14, an extrusion speed of 1.1 mm / s, an extrusion barrel temperature of 410°C, an extrusion temperature of 445°C, and water cooling or air cooling at the outlet;

[0464] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 540°C, keep it at this temperature for 90 min, and then quench it in water;

[0465] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 10 hours, and air-cooled after being taken out of the furnace;

[0466] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0467] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0468] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0469] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0470] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0471] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0472] Embodiment 35

[0473] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.35%, Si: 1.10%, Cu: 0.60%, Zn: 0.45%, Zr: 0.09%, Mn: 0.25%, Cr: 0.13%, Fe: 0.23%, Ti: 0.11%, and the balance being Al.

[0474] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 540°C for 8 h and then air-cooled;

[0475] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 440° C.

[0476] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 15, an extrusion speed of 1.5 mm / s, an extrusion barrel temperature of 430°C, an extrusion temperature of 440°C, and water cooling or air cooling at the outlet;

[0477] (5) Solution treatment: heat the 6xxx aluminum alloy extrusion profile to 555°C, keep it at this temperature for 15 min, and then quench it in water;

[0478] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0479] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0480] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0481] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0482] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0483] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0484] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0485] Embodiment 36

[0486] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.33%, Si: 1.55%, Cu: 0.48%, Zn: 0.38%, Zr: 0.12%, Mn: 0.33%, Cr: 0.11%, Fe: 0.39%, Ti: 0.11%, and the balance being Al.

[0487] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 545°C for 7 h and then air-cooled;

[0488] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0489] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 14, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0490] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 550°C, keep it at this temperature for 45 min, and then quench it in water;

[0491] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0492] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0493] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0494] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0495] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0496] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0497] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0498] Embodiment 37

[0499] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.01%, Si: 1.07%, Cu: 0.69%, Zn: 0.77%, Zr: 0.10%, Mn: 0.33%, Cr: 0.23%, Fe: 0.55%, Ti: 0.12%, and the balance being Al.

[0500] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 540°C for 7 h and then air-cooled;

[0501] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0502] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 11, an extrusion speed of 1.2 mm / s, an extrusion barrel temperature of 410°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0503] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 550°C, keep it at this temperature for 30 min, and then quench it in water;

[0504] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 12 hours, and air-cooled after being taken out of the furnace;

[0505] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0506] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0507] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0508] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0509] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0510] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0511] Embodiment 38

[0512] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.16%, Si: 1.26%, Cu: 0.52%, Zn: 0.33%, Zr: 0.13%, Mn: 0.36%, Cr: 0.11%, Fe: 0.50%, Ti: 0.26%, and the balance being Al.

[0513] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 555°C for 4 h and then air-cooled;

[0514] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 445° C.

[0515] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 13, an extrusion speed of 1.2 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 445°C, and water cooling or air cooling at the outlet;

[0516] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 30 min, and then quench it in water;

[0517] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 10 hours, and air-cooled after being taken out of the furnace;

[0518] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0519] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0520] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0521] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0522] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0523] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0524] Embodiment 39

[0525] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.16%, Si: 1.26%, Cu: 0.52%, Zn: 0.33%, Zr: 0.13%, Mn: 0.36%, Cr: 0.11%, Fe: 0.50%, Ti: 0.26%, and the balance being Al.

[0526] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 540°C for 8 h and then air-cooled;

[0527] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 440° C.

[0528] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 15, an extrusion speed of 1.5 mm / s, an extrusion barrel temperature of 430°C, an extrusion temperature of 440°C, and water cooling or air cooling at the outlet;

[0529] (5) Solution treatment: heat the 6xxx series aluminum alloy extruded bar to 555°C, keep it at this temperature for 15 min, and then quench it in water;

[0530] (6) Aging treatment: The extruded bars after solution treatment are placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0531] (7) Conducting a tensile test: Conducting a tensile test on the extruded bars of 6xxx series aluminum alloy after solid solution aging treatment in accordance with GB / T16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0532] (8) Determination of fatigue strength: The extruded bars of 6xxx aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0533] (9) Exfoliation corrosion test: Exfoliation corrosion test is performed on extruded bars of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0534] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile and fatigue tests to measure its strength, elongation and fatigue limit. The specific performance indicators are shown in Table 1.

[0535] Embodiment 40

[0536] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.34%, Si: 1.33%, Cu: 0.52%, Zn: 0.41%, Zr: 0.15%, Mn: 0.31%, Cr: 0.30%, Fe: 0.50%, Ti: 0.21%, and the balance being Al.

[0537] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 555°C for 4 h and then air-cooled;

[0538] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0539] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 12, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0540] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 540°C, keep it at this temperature for 90 min, and then quench it in water;

[0541] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0542] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0543] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0544] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0545] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0546] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0547] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0548] Embodiment 41

[0549] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.25%, Si: 1.30%, Cu: 0.55%, Zn: 0.60%, Zr: 0.10%, Mn: 0.40%, Cr: 0.10%, Fe: 0.35%, Ti: 0.10%, and the balance being Al.

[0550] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingot at 550°C for 7 h followed by air cooling;

[0551] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0552] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 13, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 410°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0553] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 540°C, keep it at this temperature for 90 min, and then quench it in water;

[0554] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0555] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0556] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0557] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0558] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0559] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0560] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0561] Embodiment 42

[0562] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.07%, Si: 1.20%, Cu: 0.59%, Zn: 0.77%, Zr: 0.11%, Mn: 0.36%, Cr: 0.29%, Fe: 0.56%, Ti: 0.09%, and the balance being Al.

[0563] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingot at 550°C for 7 h followed by air cooling;

[0564] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 450° C.

[0565] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 15, an extrusion speed of 1.5 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 450°C, and water cooling or air cooling at the outlet;

[0566] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 555°C, keep it at this temperature for 30 min, and then quench it in water;

[0567] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 10 hours, and air-cooled after being taken out of the furnace;

[0568] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0569] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0570] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0571] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0572] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0573] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0574] Embodiment 43

[0575] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 0.90%, Si: 1.00%, Cu: 0.40%, Zn: 0.30%, Zr: 0.08%, Mn: 0.32%, Cr: 0.11%, Fe: 0.29%, Ti: 0.25%, and the balance being Al.

[0576] (2) Homogenization treatment: The 6xxx aluminum alloy ingot is subjected to homogenization treatment at 540°C for 8 h and then air-cooled;

[0577] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 440° C.

[0578] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 15, an extrusion speed of 1.5 mm / s, an extrusion barrel temperature of 400°C, an extrusion temperature of 440°C, and water cooling or air cooling at the outlet;

[0579] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 540°C, keep it at this temperature for 90 min, and then quench it in water;

[0580] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 175°C and kept at this temperature for 8 hours, and then air-cooled after being taken out of the furnace;

[0581] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0582] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0583] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0584] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0585] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0586] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0587] Embodiment 44

[0588] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 0.90%, Si: 1.15%, Cu: 0.72%, Zn: 0.75%, Zr: 0.15%, Mn: 0.30%, Cr: 0.21%, Fe: 0.48%, Ti: 0.17%, and the balance being Al.

[0589] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingots at 555°C for 5 h followed by air cooling;

[0590] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 455° C.

[0591] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 13, an extrusion speed of 1.4 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 455°C, and water cooling or air cooling at the outlet;

[0592] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 550°C, keep it at this temperature for 45 min, and then quench it in water;

[0593] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 12 hours, and air-cooled after being taken out of the furnace;

[0594] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0595] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0596] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0597] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0598] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0599] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0600] Embodiment 45

[0601] (1) Ingot preparation: 6xxx series aluminum alloy round ingots were prepared by direct water-cooled semi-continuous casting, containing the following components and mass percentages: Mg: 1.25%, Si: 1.00%, Cu: 0.70%, Zn: 0.63%, Zr: 0.12%, Mn: 0.17%, Cr: 0.30%, Fe: 0.47%, Ti: 0.09%, and the balance being Al.

[0602] (2) Homogenization treatment: homogenization treatment of 6xxx aluminum alloy ingots at 555°C for 5 h followed by air cooling;

[0603] (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment to 455° C.

[0604] (4) Extrusion: The 6xxx aluminum alloy ingot after heat preservation is hot extruded with an extrusion ratio of 12, an extrusion speed of 1.3 mm / s, an extrusion barrel temperature of 420°C, an extrusion temperature of 455°C, and water cooling or air cooling at the outlet;

[0605] (5) Solution treatment: heat the 6xxx series aluminum alloy extrusion profile to 545°C, keep it at this temperature for 30 min, and then quench it in water;

[0606] (6) Aging treatment: The extruded profile after solution treatment is placed in an aging furnace, heated to 165°C for 14 hours, and air-cooled after being taken out of the furnace;

[0607] (7) Welding test: The extruded profiles after solution aging treatment were subjected to MIG welding test, and the welding material used was 5356 aluminum alloy welding wire;

[0608] (8) Conducting a tensile test: Conducting a tensile test on the extruded profiles after solution aging treatment of 6xxx series aluminum alloy and the extruded profiles after welding in accordance with GB / T 16865-2023 “Test specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products”;

[0609] (9) Calculation of welding coefficient: MIG melting welding is performed on the extruded profile using 5356 aluminum alloy welding wire. Tensile specimens are taken perpendicular to the welding direction and the welding coefficient is calculated. Welding coefficient = weld joint strength / parent material strength;

[0610] (10) Determination of fatigue strength: The extruded profiles of 6xxx series aluminum alloy after solid solution aging are subjected to fatigue test according to GB / T3075-2021 “Axial force control method for fatigue test of metallic materials” to determine their fatigue limit;

[0611] (11) Exfoliation corrosion test: Exfoliation corrosion test is performed on the extruded profiles of 6xxx series aluminum alloy after solid solution aging in accordance with GB / T22639-2022 “Exfoliation corrosion test method for aluminum alloy products”.

[0612] The 6xxx series aluminum alloy prepared in this embodiment was subjected to tensile, fatigue and welding tests to measure its strength, elongation, fatigue limit and welding coefficient. The specific performance indicators are shown in Table 1.

[0613] Table 1 Mechanical properties data of Examples 1 to 45 and Comparative Example 1

[0614]

[0615]

Claims

1. A method for preparing a high-strength weldable 6xxx series aluminum alloy and an extruded material thereof, comprising the following steps: (1) preparing a 6xxx series aluminum alloy round ingot; (2) Homogenization treatment: The 6xxx series aluminum alloy ingot is homogenized and then air-cooled; (3) Heating: heating the 6xxx aluminum alloy ingot after homogenization treatment; (4) Extrusion: hot extrusion of the 6xxx series aluminum alloy ingot after heat preservation; (5) Solution treatment: The 6xxx series aluminum alloy extruded profile / bar is heated and kept warm for a period of time before being water quenched; (6) Aging treatment: The extruded profiles / bars after solution treatment are placed in an aging furnace, heated and kept warm for a period of time, and then air-cooled after being taken out of the furnace.

2. The method for preparing a high-strength weldable 6xxx series aluminum alloy and an extruded material thereof according to claim 1, characterized in that: In the step (1), the components contained in the 6xxx series aluminum alloy and their mass percentages are: Mg: 0.90-1.45%, Si: 1.00-1.55%, Cu: 0.40-0.80%, Zn: 0.30-0.80%, Zr: 0.08-0.15%, Mn≤0.50%, Cr≤0.35%, Fe≤0.60%, Ti≤0.30, and the balance is Al.

3. The method for preparing a high-strength weldable 6xxx series aluminum alloy and an extruded material thereof according to claim 1, characterized in that: In the step (1), the 6xxx series aluminum alloy round ingot is produced by direct water-cooled semi-continuous casting (DC casting for short).

4. The method for preparing a high-strength weldable 6xxx series aluminum alloy and an extruded material thereof according to claim 1, characterized in that: In the step (2), the homogenization treatment process of the 6xxx series aluminum alloy ingot is 540-555°C×4-8h.

5. The method for preparing a high-strength weldable 6xxx series aluminum alloy and an extruded material thereof according to claim 1, characterized in that: In the step (3), the 6xxx series aluminum alloy ingot after homogenization treatment is heated to 440-460°C.

6. The method for preparing a high-strength weldable 6xxx series aluminum alloy and an extruded material thereof according to claim 1, characterized in that: In the step (4), the hot extrusion process of the 6xxx series aluminum alloy ingot is as follows: an extrusion ratio of 10 to 15, an extrusion speed of 1.0 to 1.5 mm / s, an extrusion barrel temperature of 400 to 430°C, an extrusion temperature of 440 to 460°C, and water cooling or air cooling at the outlet.

7. The method for preparing a high-strength weldable 6xxx series aluminum alloy and an extruded material thereof according to claim 1, characterized in that: In the step (5), the solution treatment process of the 6xxx series aluminum alloy extruded profile / rod is 540-555°C×15-90min.

8. The method for preparing a high-strength weldable 6xxx series aluminum alloy and an extruded material thereof according to claim 1, characterized in that: In the step (6), the aging process of the 6xxx series aluminum alloy extruded profile / rod is 165-175°C×8-14h.

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