New energy vehicle protection system multi-cavity complex structure profile extrusion production process

Abstract

A new energy automobile protection system multi-cavity complex structure profile extrusion production process belongs to the technical field of aluminum alloy, and the process optimizes alloy components, controls melting and casting process, adjusts casting rod homogenization system, improves mold structure, and controls extrusion process parameter precision, greatly improves the mechanical property precision of the complex structure profile for the automobile protection system under the premise of ensuring the stability of the profile size, the yield strength can reach 300+5MPa, the tensile strength is above 370MPa, and the elongation is above 17%, which meets the standard requirements of high performance, high precision and high energy absorption of the profile for the automobile protection system, and improves the overall quality of the new energy automobile.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy processing technology, specifically relating to an extrusion production process for multi-cavity complex structure profiles used in protective systems for new energy vehicles. Background Technology

[0002] Currently, with my country increasingly emphasizing energy conservation and emission reduction, 6-series aluminum alloys are widely used in the automotive industry due to their abundant resources, high specific strength, and excellent comprehensive performance. 6082 aluminum alloy, a high-content 6-series aluminum alloy with high Si and Mg content, possesses not only high strength but also a certain energy absorption effect, making it one of the best materials for automotive collision protection systems. Because automotive collision protection systems not only pursue maximum mechanical strength but also emphasize energy absorption, more and more automotive manufacturers are demanding specific ranges for the yield strength of 6082 extruded aluminum alloys. This improvement in performance standards places higher demands on the microstructure of raw aluminum alloy ingots, extrusion processes, and extrusion equipment. To meet market demand, a production process suitable for multi-cavity complex structure thin-walled profiles was developed. By controlling the ingot homogenization temperature, die structure, extrusion process parameters, adjusting the aging regime, and fine-tuning the extrusion bar speed based on the online extrusion dimensions of the profile, a process suitable for 6082 multi-cavity complex structure thin-walled profiles for automotive protection systems was successfully developed. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an extrusion production process for multi-cavity complex structure profiles used in protective systems for new energy vehicles. Based on the GB / T3190 standard, the composition of the 6082 alloy is fine-tuned to ensure the mechanical properties of the profile while improving alloy fluidity and increasing filling capacity. The profile cross-section is as follows: Figure 1 As shown.

[0004] By adjusting the casting rod homogenization process, improving the mold structure, ensuring uniform metal flow rate at all locations of the profile, and strictly monitoring the production process, it is possible to efficiently extrude thin-walled aluminum profiles with an outer circle diameter of φ158mm, a three-cavity structure, a wall thickness of 3.3-4mm, a yield strength range of 300±5MPa, and high-precision mechanical properties that meet the standards for automotive protective systems.

[0005] In terms of composition design: Si: 1.00%~1.30%, Fe: 0.10%~0.20%, Cu: 0.01%~0.03%, Mn: 0.60%~0.70%, Mg: 0.60%~0.80%, Cr: 0.10%~0.20%, Zn: ≤0.20%, other individual impurity elements ≤0.05%, total impurity content ≤0.15%, balance is Al. The Mg2Si content in the composition needs to be controlled within the range of 0.9%~1.1%, and the excess Si content should be ≤0.3%. This composition design maximizes the metal filling ability while ensuring mechanical properties.

[0006] Regarding casting control: Ingots are produced using a semi-continuous casting method. Foam ceramic filtration is employed during the casting process, and Al-Ti-B grain refiner wire is used to refine the grains. The amount of scrap aluminum added is controlled to ≤12%. The scrap aluminum originates from substandard aluminum products in the aluminum alloy industrial materials, aluminum alloy building materials, and rail transportation and automotive aluminum alloy profiles, involving 6-series aluminum alloys. The amount of scrap aluminum added for these industrial and / or transportation applications should be controlled within the range of ≤12%.

[0007] Melting temperature: 710℃-760℃; refining temperature: 730℃-755℃; refining agent dosage: 1.3-1.7 kg / TAl; refining time: 25-35 min; slag removal temperature: 733℃-745℃; converter temperature: 750℃-760℃; settling temperature: 720℃-735℃; online degassing rotor speed: 500 r / min; gas flow rate: 900 L / h; filter plate specification: 30 ppi; slag content of ingots must meet the secondary requirements in GB / T32186-2015; hydrogen element: 0.15-0.18 ml / 100g; casting speed during casting: 110-150 mm / min; cooling water flow rate: 12-18 m³ / min. 3 / h, casting plate temperature 680℃-700℃.

[0008] Regarding the homogenization of the casting rods: During the semi-continuous casting process, the chemical composition and microstructure inside the ingot are unevenly distributed, and intragranular and regional segregation occurs during rapid cooling, affecting the internal quality and high-temperature plasticity of the ingot. Therefore, a high-temperature, long-term homogenization process is adopted for the casting rods, with a temperature of 560℃-580℃ and a holding time of 10-12 hours. This eliminates internal stress in the ingot, promotes the dissolution of non-equilibrium solidified phases, ensures uniform distribution of chemical composition, and eliminates internal segregation.

[0009] In terms of mold design: the profile wall thickness is uneven, with thinner sections at 3.3mm and thicker sections at 4mm. To ensure consistent flow velocity throughout the profile, a flow-blocking chamfer was added at the 4mm thick section, increasing the angle from 3° to 7°. This resulted in a uniform flow velocity across the profile. Overall, the working zone width was reduced from 5mm to below 4mm, achieving stable mechanical properties while maintaining dimensional accuracy.

[0010] In terms of extrusion process: A 2750T horizontal extrusion press is used to produce automotive protective system profiles with a complex three-cavity structure, an outer diameter of φ158mm, and a wall thickness of 3.3-4mm. Production is carried out using 680mm short ingots, with the breakthrough pressure controlled between 22-24MPa to protect the die and maintain dimensional accuracy. The quenching method has been changed from water quenching to water mist cooling, which can simultaneously meet ultra-high standard dimensional requirements and high-precision mechanical performance standards. The die temperature is controlled at 480℃-510℃, the extrusion ingot temperature at 480℃-500℃, and the profile exit temperature at 510℃-550℃. The extrusion bar speed is 3.2-3.5mm / s. In the aging furnace, samples are spaced 2-3cm apart, with 90-110 samples placed. The aging regime is 175℃ × 5.5h.

[0011] The beneficial effects of this invention are:

[0012] The original aluminum profiles used in automotive anti-collision systems had simple cross-sectional structures, regular shapes, wide dimensional tolerances, and no specific requirements for mechanical properties, which no longer meet the current development trends of high-quality new energy vehicles both domestically and internationally. Today, automotive protective system profiles have higher standards for yield strength. Too low a yield strength fails to meet the vehicle's rigidity requirements, while too high a yield strength reduces material plasticity and weakens energy absorption during collisions. Therefore, by optimizing alloy composition, controlling the casting process and adjusting the homogenization regime of the casting rod, improving the die structure, and controlling the precision of extrusion process parameters, the mechanical properties of complex structural profiles for automotive protective systems have been greatly improved while ensuring dimensional stability. Yield strength can reach within the range of 300±5MPa, tensile strength above 370MPa, and elongation above 17%, meeting the high-performance, high-precision, and high-energy-absorbing standards for automotive protective system profiles and improving the overall quality of new energy vehicles. Attached Figure Description

[0013] Figure 1 Profile cross-section drawing;

[0014] Figure 2 Metallographic high-magnification images of Example 1; where A is the matrix grain size diagram, B is the matrix structure diagram, and C is the profile edge cortex thickness diagram;

[0015] Figure 3 Results of intergranular corrosion performance test in Example 1;

[0016] Figure 4 Metallographic high-magnification images of Example 2; where A is the matrix grain size diagram, B is the matrix structure diagram, and C is the profile edge cortex thickness diagram;

[0017] Figure 5Results of intergranular corrosion performance test in Example 2;

[0018] Figure 6 Metallographic high-magnification images of Example 3; where A is the matrix grain size diagram, B is the matrix structure diagram, and C is the profile edge cortex thickness diagram;

[0019] Figure 7 Results of intergranular corrosion performance test in Example 3. Detailed Implementation

[0020] In Examples 1-3 below, the online degassing rotor speed is 500 r / min, the gas flow rate is 900 L / h, the filter plate specification is 30 ppi, and the slag content of the ingot must meet the Class II requirements in GB / T32186-2015. The casting speed during casting is 110-150 mm / min, and the cooling water flow rate is 12-18 m³ / min. 3 / h, casting plate temperature 680-700℃.

[0021] Example 1

[0022] A manufacturing process for extruding multi-cavity complex structure profiles for protective systems in new energy vehicles includes the following steps:

[0023] 1. Composition: Test equipment: ARL-3460 direct-reading spectrometer. Test method: GB / T7999-2015 Direct-reading photoelectric emission spectrometry analysis method for aluminum and aluminum alloys.

[0024] content% 1.21 0.12 0.02 0.66 0.68 0.14 0.01 0.05 margin

[0025] 2. Melting and Casting Process: Melting temperature 710℃-760℃, refining temperature 730℃-750℃, refining agent dosage 1.5kg / TAl, refining time 25min, slag removal temperature 733℃, converter temperature 750℃, settling temperature 720℃, waste addition not exceeding 11%, and the slag content of the ingot must meet the Class II requirements in GB / T32186-2015. Hydrogen element 0.15ml / 100g. Homogenization treatment temperature is 560℃, holding time is 10h.

[0026] 3. Mold design: Add a 7° flow-blocking chamfer to the thick-walled section and a working zone width of 3mm.

[0027] 4. Extrusion process: A 2750T horizontal extrusion press is used to produce an outer diameter of φ158mm, a wall thickness of 3.6mm, a breaking pressure of 23MPa, and online water cooling production. The selected casting rod length is 680mm, the casting rod heating temperature is 490℃, the die heating temperature is 495℃, the extrusion cylinder temperature is 422℃, the extrusion rod speed is 3.3m / min, and the aging regime is 175℃×5.5h.

[0028] 5. Mechanical Properties: Test Equipment: AG-X 100KN Electronic Universal Testing Machine. Test Method: GB / T16865-2013 Tensile Testing of Wrought Aluminum, Magnesium and Their Alloys.

[0029] Table 1 Mechanical property results

[0030]

[0031]

[0032] 6. High-magnification microstructure: Testing equipment: AXIO universal research-grade inverted materials microscope. Testing standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extruded profiles. Testing method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy products - Microstructure inspection methods - Part 1: Microstructure inspection methods.

[0033] Test results: such as Figure 2 As shown, the matrix grain size is grade 7, no burning has been observed, and the thickness of the cortical layer at the edge is 137.65 μm;

[0034] Conclusion: Qualified.

[0035] 7. Fusion Joint Test: Testing Equipment: Aluminum Profile Compression Testing Machine. Testing Standard: GB / T6892-2015 General Industrial Aluminum and Aluminum Alloy Extruded Profiles. Testing Method: GB / T32790-2016 Test Method for Welding Performance of Extruded Welds in Aluminum and Aluminum Alloys.

[0036] Table 2. Fusion Joint Test

[0037]

[0038] 8. Low-magnification test: The test equipment uses an alkaline corrosive solution. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extruded profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy products - Microstructure inspection methods - Part 2: Low-magnification microstructure inspection methods.

[0039] Table 3 Low-magnification tissue test

[0040]

[0041] 9. Bending performance test: Test equipment: AG-X 100KN electronic universal testing machine. Test standard: VDA238-100 Test Specification for Bending Test of Metallic Materials (Plate).

[0042] Table 4. Bending performance test results

[0043]

[0044]

[0045] 10. Intergranular corrosion test: Test equipment: AXIO universal research-grade inverted materials microscope. Test standard: ISO 14846 Method B.

[0046] Test results: such as Figure 3 As shown, the intergranular corrosion depth is 130.85 μm;

[0047] Conclusion: Qualified.

[0048] 11. Exfoliation Corrosion Performance Test: The testing equipment is a digital display constant temperature water bath. Test standard: GB / T22639-2008 Exfoliation Corrosion Test Method for Aluminum Alloy Processed Products.

[0049] Table 5. Exfoliation Corrosion Test

[0050]

[0051] Example 2

[0052] A manufacturing process for extruding multi-cavity complex structure profiles for protective systems in new energy vehicles includes the following steps:

[0053] 1. Composition: Test equipment: ARL-3460 direct-reading spectrometer. Test method: GB / T7999-2015 Direct-reading photoelectric emission spectrometry analysis method for aluminum and aluminum alloys.

[0054] content% 1.26 0.11 0.01 0.68 0.72 0.15 0.01 0.05 margin

[0055] 2. Melting and Casting Process: Melting temperature 720℃-750℃, refining temperature 740℃-750℃, refining agent dosage 1.3kg / TAl, refining time 28min, slag removal temperature 739℃, converter temperature 755℃, settling temperature 729℃, waste addition not exceeding 12%, and the slag content of the ingot must meet the Class II requirements in GB / T32186-2015. Hydrogen element 0.17ml / 100g. Homogenization treatment temperature is 560℃, holding time is 10h.

[0056] 3. Mold design: Add a 7° flow-blocking chamfer to the thick-walled section and a working zone width of 4mm.

[0057] 4. Extrusion Process: A 2750T horizontal extrusion press is used to produce a profile with an outer diameter of φ158mm, a wall thickness of 3.5mm, a breaking pressure of 24MPa, and online water cooling. The selected casting rod length is 680mm, the casting rod heating temperature is 495℃, the die heating temperature is 487℃, the extrusion cylinder temperature is 426℃, the extrusion rod speed is 3.4m / min, and the profile exit temperature is within the range of 520℃. The distance between samples in the aging furnace is 2.5cm, the number of samples is 97, and the aging regime is 175℃×5.5h.

[0058] 5. Mechanical Properties: Test Equipment: AG-X 100KN Electronic Universal Testing Machine. Test Method: GB / T16865-2013 Tensile Testing of Wrought Aluminum, Magnesium and Their Alloys.

[0059] Table 6 Mechanical property results

[0060]

[0061] 6. High-magnification microstructure: Testing equipment: AXIO universal research-grade inverted materials microscope. Testing standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extruded profiles. Testing method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy products - Microstructure inspection methods - Part 1: Microstructure inspection methods.

[0062] Test results: such as Figure 4 As shown, the matrix grain size is grade 7, no burning has been observed, and the thickness of the edge cortex layer is 163.3 μm;

[0063] Conclusion: Qualified.

[0064] 7. Fusion Joint Test: Testing Equipment: Aluminum Profile Compression Testing Machine. Testing Standard: GB / T6892-2015 General Industrial Aluminum and Aluminum Alloy Extruded Profiles. Testing Method: GB / T32790-2016 Test Method for Welding Performance of Extruded Welds in Aluminum and Aluminum Alloys.

[0065] Table 7. Fusion Joint Test

[0066]

[0067] 8. Low-magnification test: The test equipment uses an alkaline corrosive solution. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extruded profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy products - Microstructure inspection methods - Part 2: Low-magnification microstructure inspection methods.

[0068] Table 8 Low-magnification tissue test

[0069]

[0070] 9. Bending performance test: Test equipment: AG-X 100KN electronic universal testing machine. Test standard: VDA238-100 Test Specification for Bending Test of Metallic Materials (Plate).

[0071] Table 9 Bending Performance Test Results

[0072]

[0073]

[0074] 10. Intergranular corrosion test: Test equipment: AXIO universal research-grade inverted materials microscope. Test standard: ISO 14846 Method B.

[0075] Test results: such as Figure 5 As shown, the intergranular corrosion depth is 153.90 μm;

[0076] Conclusion: Qualified.

[0077] 11. Exfoliation Corrosion Performance Test: The testing equipment is a digital display constant temperature water bath. Test standard: GB / T22639-2008 Exfoliation Corrosion Test Method for Aluminum Alloy Processed Products.

[0078] Table 10 Exfoliation Corrosion Test

[0079]

[0080] Example 3

[0081] A manufacturing process for extruding multi-cavity complex structure profiles for protective systems in new energy vehicles includes the following steps:

[0082] 1. Composition: Test equipment: ARL-3460 direct-reading spectrometer. Test method: GB / T7999-2015 Direct-reading photoelectric emission spectrometry analysis method for aluminum and aluminum alloys.

[0083] content% 1.24 0.13 0.01 0.64 0.71 0.18 0.01 0.05 margin

[0084] 2. Melting and Casting Process: Melting temperature 715℃-755℃, refining temperature 730℃-755℃, refining agent dosage 1.7kg / TAl, refining time 33min, slag removal temperature 744℃, converter temperature 760℃, settling temperature 735℃, waste addition not exceeding 9%, and the slag content of the ingot must meet the Class II requirements in GB / T32186-2015. Hydrogen element 0.18ml / 100g. Homogenization treatment temperature is 560℃, holding time is 10h.

[0085] 3. Mold design: Add a 7° flow-blocking chamfer to the thick-walled section, and the working zone width is 3.4mm.

[0086] 4. Extrusion Process: A 2750T horizontal extrusion press is used to produce a profile with an outer diameter of φ158mm, a wall thickness of 3.5mm, a breaking pressure of 23MPa, and online water cooling. The selected casting rod length is 680mm, the casting rod heating temperature is 494℃, the die heating temperature is 490℃, the extrusion cylinder temperature is 425℃, the extrusion rod speed is 3.5m / min, and the profile exit temperature is within the range of 515℃. The samples in the aging furnace are spaced 3cm apart, and the number of samples is 99. The aging regime is 175℃×5.5h.

[0087] 5. Mechanical Properties: Test Equipment: AG-X 100KN Electronic Universal Testing Machine. Test Method: GB / T16865-2013 Tensile Testing of Wrought Aluminum, Magnesium and Their Alloys.

[0088] Table 11 Mechanical property results

[0089]

[0090] 6. High-magnification microstructure: Testing equipment: AXIO universal research-grade inverted materials microscope. Testing standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extruded profiles. Testing method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy products - Microstructure inspection methods - Part 1: Microstructure inspection methods.

[0091] Test results: such as Figure 6 As shown, the matrix grain size is grade 7, no burning has been observed, and the thickness of the cortical layer at the edge is 156.38 μm;

[0092] Conclusion: Qualified.

[0093] 7. Fusion Joint Test: Testing Equipment: Aluminum Profile Compression Testing Machine. Testing Standard: GB / T6892-2015 General Industrial Aluminum and Aluminum Alloy Extruded Profiles. Testing Method: GB / T32790-2016 Test Method for Welding Performance of Extruded Welds in Aluminum and Aluminum Alloys.

[0094] Table 12 Fusion Joint Test

[0095]

[0096] 8. Low-magnification test: The test equipment uses an alkaline corrosive solution. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extruded profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy products - Microstructure inspection methods - Part 2: Low-magnification microstructure inspection methods.

[0097] Table 13 Low-magnification tissue test

[0098]

[0099] 9. Bending performance test: Test equipment: AG-X 100KN electronic universal testing machine. Test standard: VDA238-100 Test Specification for Bending Test of Metallic Materials (Plate).

[0100] Table 14 Bending Performance Test Results

[0101]

[0102]

[0103] 10. Intergranular corrosion test: Test equipment: AXIO universal research-grade inverted materials microscope. Test standard: ISO 14846 Method B.

[0104] Test results: such as Figure 7 As shown, the intergranular corrosion depth is 132.20 μm;

[0105] Conclusion: Qualified.

[0106] 11. Exfoliation Corrosion Performance Test: The testing equipment is a digital display constant temperature water bath. Test standard: GB / T22639-2008 Exfoliation Corrosion Test Method for Aluminum Alloy Processed Products.

[0107] Table 15 Exfoliation Corrosion Test

[0108]

Claims

1. A manufacturing process for extruding multi-cavity complex structure profiles for protective systems in new energy vehicles, characterized in that, The production of profiles with a three-cavity structure and a wall thickness of 3.3-4mm includes the following steps: Composition design: Si: 1.00%~1.30%, Fe: 0.10%~0.20%, Cu: 0.01%~0.03%, Mn: 0.60%~0.70%, Mg: 0.60%~0.80%, Cr: 0.10%~0.20%, Zn: ≤0.20%, other individual impurity elements ≤0.05%, total impurity content ≤0.15%, balance is Al, the Mg2Si content in the composition is controlled within the range of 0.9%~1.1%, and the excess Si content should be ≤0.3%; Melting and casting control: Ingots are produced using a semi-continuous casting method. Foam ceramic filtration is used during the casting process, and Al-Ti-B grain refiner wire is used to refine the grains. The amount of scrap aluminum added is controlled to be ≤12%. In the casting process, the melting temperature is 710℃-760℃, the refining temperature is 730℃-755℃, the refining agent dosage is 1.3-1.7kg / TAl, the refining time is 25-35min, the slag removal temperature is 733℃-745℃, the converter temperature is 750℃-760℃, the settling temperature is 720℃-735℃, the online degassing rotor speed is 500r / min, the gas flow rate is 900L / h, the filter plate specification is 30ppi, and the hydrogen element is 0.15-0.18ml / 100g. Homogenization of casting rods: High-temperature and long-time homogenization of casting rods is carried out at 560℃-580℃ for 10-12 hours. Extrusion process: control the breakthrough pressure between 22-24MPa; change the quenching method from water quenching to water mist cooling; control the die temperature at 480℃-510℃, the extrusion ingot temperature at 480℃-500℃, and the profile exit temperature at 510℃-550℃; the extrusion rod speed is 3.2-3.5mm / s; the distance between samples in the aging furnace is 2-3cm, the number of samples is 90-110, and the aging regime is 175℃×5.5h.

2. The extrusion production process of a multi-cavity complex structure profile for a protective system in new energy vehicles according to claim 1, characterized in that, The produced profiles have a yield strength range of 300±5MPa, a tensile strength of over 370MPa, and an elongation of over 17%.

3. The extrusion production process of a multi-cavity complex structure profile for a protective system in new energy vehicles according to claim 1, characterized in that, In the casting process, the casting speed is 110-150 mm / min, and the cooling water flow rate is 12-18 m³ / min. 3 / h, casting plate temperature 680℃-700℃.

4. The extrusion production process of a multi-cavity complex structure profile for a protective system for new energy vehicles according to claim 1, characterized in that, The production process also includes: Mold design: Increase the flow-blocking chamfer at the 4mm wall thickness from 3° to 7°, and reduce the working band width from 5mm to below 4mm.

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