Al-Mg-Si0.5 high-strength high-conductivity aluminum alloy thick plate for electrical field and preparation method of Al-Mg-Si0.5 high-strength high-conductivity aluminum alloy thick plate

Abstract

The invention discloses an Al-Mg-Si0.5 high-strength and high-conductivity aluminum alloy thick plate for the electrical field and a preparation method of the Al-Mg-Si0.5 high-strength and high-conductivity aluminum alloy thick plate, and relates to a high-strength and high-conductivity aluminum alloy thick plate and a preparation method thereof. The invention aims to solve the problem that Al-Mg-Si0.5 alloy plates produced by the existing process cannot meet the requirements of high strength and high conductivity of aluminum alloys of part of current electrical equipment. A brand new heat treatment process system is designed while component design is optimized, the prepared Al-Mg-Si0.5-T63 state alloy has the IACS index requirements that the tensile strength is larger than or equal to 175 MPa, the yield strength is larger than or equal to 132 MPa, the ductility is larger than or equal to 14% and the conductivity is larger than or equal to 55%, the flatness of a prepared sheet can also be guaranteed after the stretching procedure, and the product quality is guaranteed. The method is applied to the field of aluminum alloy manufacturing.

Description

Technical Field

[0001] This invention relates to a high-strength, high-conductivity aluminum alloy thick plate of Al-Mg-Si0.5 for electrical applications and its preparation method. Background Technology

[0002] 6xxx series aluminum alloys, as typical heat-treatable aluminum alloys, occupy an irreplaceable position in industrial production and daily life due to their good strength, excellent corrosion resistance, superior extrusion formability, and surface treatment performance. 6xxx series aluminum alloys are aluminum alloys with magnesium and silicon as the main alloying elements and Mg2Si phase as the strengthening phase, belonging to the category of heat-treatable aluminum alloys. The alloys possess advantages such as moderate strength, high corrosion resistance, no stress corrosion cracking tendency, good weldability, unchanged corrosion performance in the weld zone, and good formability and processing performance, exhibiting optimal comprehensive performance. They are widely used in important industrial fields such as aerospace, military equipment, marine engineering, and high-voltage electrical systems. In the manufacture of high-voltage electrical equipment, Al-Mg-Si0.5 aluminum alloy in the 6xxx series, as an early and widely used aluminum-magnesium-silicon aluminum alloy, is mainly used in the electrical and electronics industries for manufacturing electrical components such as busbars, conductors, electrical conductors, heat sinks, transformer windings, and high-strength wires. With the vigorous development of China's electrical and electronic industry, the requirements for the size and performance of materials have also increased significantly. Al-Mg-Si0.5 alloy plates produced according to the previous production process can no longer meet the requirements of high strength and high conductivity of aluminum alloys for some electrical equipment. Summary of the Invention

[0003] This invention addresses the problem that existing Al-Mg-Si0.5 alloy plates produced by current processes can no longer meet the high strength and high conductivity requirements of aluminum alloys in some electrical equipment. The invention provides a high-strength, high-conductivity Al-Mg-Si0.5 aluminum alloy thick plate for electrical applications and its preparation method.

[0004] This invention discloses an Al-Mg-Si0.5 high-strength, high-conductivity aluminum alloy thick plate for electrical applications, composed of 0.4%~0.8% Si, 0.4%~0.6% Fe, 0.15%~0.4% Cu, 0.04%~0.08% Mn, 0.8%~1.2% Mg, 0.15%~0.5% Cr, 0.04%~0.08% Zn, 0.04%~0.08% Ti, and the balance being Al. The content of any single impurity does not exceed 0.05%, with the balance being Al.

[0005] A method for preparing a high-strength, high-conductivity Al-Mg-Si0.5 aluminum alloy thick plate for electrical applications is as follows:

[0006] I. Aluminum alloy thick plates are prepared according to the following chemical composition mass fraction ratios: Si 0.4%~0.8%, Fe 0.4%~0.6%, Cu 0.15%~0.4%, Mn 0.04%~0.08%, Mg 0.8%~1.2%, Cr 0.15%~0.5%, Zn 0.04%~0.08%, Ti 0.04%~0.08%, and the balance being Al. The raw materials are then melted at a temperature of 700℃~750℃ for 5h~7h to obtain aluminum alloy melt.

[0007] II. A semi-continuous water-cooled casting method is used to cast aluminum alloy molten metal into ingots;

[0008] 3. The ingot is surface treated and then heated at 530℃~570℃ for 5h~6h; the heating temperature is then changed to 430℃~470℃ for 3h~5h; the metal is then rolled at a furnace exit temperature of 400℃~440℃ to obtain the raw sheet.

[0009] Fourth, the raw material sheet is cut, then subjected to solution quenching, stretched and then aged to obtain the finished sheet.

[0010] This invention achieves the stable production of high-strength, high-conductivity aluminum alloy thick plates made of Al-Mg-Si0.5 alloy. Based on actual production, and targeting Al-Mg-Si0.5 alloys with thicknesses ranging from 2-20 mm, a novel heat treatment process was designed while optimizing the composition. The Al-Mg-Si0.5-T63 alloy produced by this invention exhibits mechanical properties far exceeding the performance requirements of Al-Mg-Si0.5-T63 alloys in the ASTM standard: tensile strength ≥175 MPa, yield strength ≥132 MPa, elongation ≥14%, and electrical conductivity ≥55% IACS. Other properties also fully meet the standard requirements. Furthermore, the flatness of the resulting plates is guaranteed after the stretching process. This method can be applied to the production of high-strength, high-conductivity Al-Mg-Si0.5 aluminum alloy thick plates. The Al-Mg-Si0.5-T63 plates produced by this method effectively balance the matching relationship between mechanical and electrical properties. Attached Figure Description

[0011] Figure 1 Figure a shows a physical image of the Al-Mg-Si0.5 high-strength, high-conductivity aluminum alloy thick plate for electrical applications prepared in Example 1;

[0012] Figure 2 Image b shows a physical copy of the Al-Mg-Si0.5 high-strength, high-conductivity aluminum alloy thick plate for electrical applications prepared in Example 1. Detailed Implementation

[0013] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0014] Specific Implementation Method 1: This implementation method describes a high-strength, high-conductivity aluminum alloy thick plate for the electrical field, consisting of 0.4%~0.8% Si, 0.4%~0.6% Fe, 0.15%~0.4% Cu, 0.04%~0.08% Mn, 0.8%~1.2% Mg, 0.15%~0.5% Cr, 0.04%~0.08% Zn, 0.04%~0.08% Ti, and the balance Al.

[0015] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the aluminum alloy thick plate is composed of 0.53% Si, 0.47% Fe, 0.25% Cu, 0.06% Mn, 1.0% Mg, 0.35% Cr, 0.05% Zn, 0.06% Ti, and the balance Al by mass fraction. Everything else is the same as in Specific Implementation Method One.

[0016] Specific Implementation Method 3: This implementation method describes a method for preparing a high-strength, high-conductivity aluminum alloy thick plate of Al-Mg-Si0.5 for the electrical field.

[0017] I. Aluminum alloy thick plates are prepared according to the following chemical composition mass fraction ratios: Si 0.4%~0.8%, Fe 0.4%~0.6%, Cu 0.15%~0.4%, Mn 0.04%~0.08%, Mg 0.8%~1.2%, Cr 0.15%~0.5%, Zn 0.04%~0.08%, Ti 0.04%~0.08%, and the balance being Al. The raw materials are then melted at a temperature of 700℃~750℃ for 5h~7h to obtain aluminum alloy melt.

[0018] II. A semi-continuous water-cooled casting method is used to cast aluminum alloy molten metal into ingots;

[0019] 3. The ingot is surface treated and then heated at 530℃~570℃ for 5h~6h; the heating temperature is then changed to 430℃~470℃ for 3h~5h; the metal is then rolled at a furnace exit temperature of 400℃~440℃ to obtain the raw sheet.

[0020] Fourth, the raw material sheet is cut, then subjected to solution quenching, stretched and then aged to obtain the finished sheet.

[0021] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method Three in that: the casting temperature in step two is 690℃~720℃, the casting speed is 40mm / min~50mm / min, the liquid level is 75mm~100mm, and the cooling water flow rate is 110M. 3 / h~180M 3 / h. Everything else is the same as in Specific Implementation Method Three.

[0022] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods Three or Four in that the surface treatment in step three involves milling the surface of the ingot, with a milling amount of 5mm to 30mm and a maximum milling amount of ≤40mm. Everything else is the same as in Specific Implementation Methods Three or Four.

[0023] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods Three to Five in that the rolling speed in step three is 1.2 m / s to 2.0 m / s. Everything else is the same as in Specific Implementation Methods Three to Five.

[0024] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods Three to Six in that the solution quenching in step four is performed as follows: a constant temperature of 545~555℃, a heating time of 15min~30min, a holding time of 10min~15min, followed by quenching treatment, with a quenching transfer time of 15s~40s. Everything else is the same as in Specific Implementation Methods Three to Five.

[0025] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods Three to Seven in that the stretching amount in step four is 1.2~1.4%. Everything else is the same as in Specific Implementation Methods Three to Seven.

[0026] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods Three to Eight in that the aging process in step four is as follows: the aging furnace is set to a constant temperature of 225°C, the lowest metal temperature is measured at 195°C, then the temperature is changed to a constant 205°C and held for 10 hours; the metal temperature is required to be 190~210°C / 10 hours before being removed from the furnace. Everything else is the same as in Specific Implementation Methods Three to Eight.

[0027] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods Three to Nine in that the Al-Mg-Si0.5 high-strength, high-conductivity aluminum alloy thick plate for the electrical field meets the following requirements: tensile strength ≥175MPa, yield strength ≥132MPa, elongation ≥14%, and conductivity ≥55%IACS. All other requirements are the same as in Specific Implementation Methods Three to Nine.

[0028] The beneficial effects of the present invention are verified using the following embodiments:

[0029] Example 1: A method for preparing a high-strength, high-conductivity aluminum alloy thick plate of Al-Mg-Si0.5 for electrical applications is as follows:

[0030] I. Alloy thick plates are prepared according to the following chemical composition mass fraction ratio: Si 0.53%, Fe 0.47%, Cu 0.25%, Mn 0.06%, Mg 1.0%, Cr 0.35%, Zn 0.05%, Ti 0.06%, and the balance Al. The raw materials are weighed and then placed in a dry reverberatory furnace or medium-frequency induction furnace and melted at a temperature of 730±10℃ for 6±1h to obtain aluminum alloy melt.

[0031] II. The aluminum alloy melt produced in step one is cast into aluminum ingots using a semi-continuous water-cooled casting method. The casting temperature is controlled at 710±10℃, the casting speed at 45±5mm / min, the liquid level at 90±5mm, and the cooling water flow rate at 150±10M. 3 / h.

[0032] Third, the ingots produced in step two are surface treated by milling a layer on the entire surface of the ingot. The milling amount is 20±10mm, and the maximum milling amount does not exceed 40mm. The milled ingots are then sawn.

[0033] 4. Place the ingot, after surface treatment in step 3, into a pusher-type or trolley-type heating furnace for heating. Set the heating temperature to 550±20℃ and the heating time to 6 hours; then change the heating temperature to 450℃±20℃ and the heating time to 5 hours. The metal exiting the furnace should be 450℃±10℃. The rolling speed is 1.6m / s±0.2m / s, and the number of rolling passes is pre-designed according to the thickness of the finished sheet to obtain the raw sheet.

[0034] 5. The raw sheet material is cut to length using a rolling mill with heavy or light shearing, controlling the length cutting error to ≤100mm. Then, it is subjected to solution quenching in a roller hearth furnace. The solution quenching process is as follows: constant temperature 550℃, heating time 30min, holding time 15min. After the holding time, the quenching process is automatically performed, and the quenching transfer time is 25±15s, resulting in solution quenched sheet material.

[0035] VI. After solution quenching, the sheet is stretched by 1.2-1.4%. The stretched sheet is then subjected to aging treatment. The aging process is as follows: the aging furnace is heated to a constant temperature of 225℃, the lowest metal temperature reaches 195℃, then the temperature is changed to a constant 205℃ and held for 10 hours. The required metal temperature is 190-210℃ / 10 hours before removal from the furnace. After aging, the sheet is precision sawn to obtain finished sheet material. Samples are taken for mechanical property testing, and the electrical conductivity is tested on the surface of the finished sheet. The properties and conductivity are shown in Table 1.

[0036] The preparation method of the ingot in Comparative Example 1 is as follows:

[0037] I. The chemical composition (mass fraction) of the ingot is as follows: Si 0.53%, Fe 0.47%, Cu 0.25%, Mn 0.06%, Mg 1.0%, Cr 0.35%, Zn 0.05%, Ti 0.06%, with the content of a single impurity not exceeding 0.05%, and the balance being Al. Weigh the raw materials according to the proportions, place them in a dry reverberatory furnace or medium-frequency induction furnace, and melt them at 730℃ for 6 hours to obtain molten aluminum alloy.

[0038] II. The aluminum alloy melt produced in step one is cast into aluminum ingots using a semi-continuous water-cooled casting method. The casting temperature is controlled at 710℃, the casting speed at 45mm / min, the liquid level at 90mm, and the cooling water flow rate at 150m³ / min. 3 / h.

[0039] Third, perform surface treatment on the ingots produced in step two by milling a layer off the entire surface of the ingot. The milling amount should be 25mm, with a maximum milling amount not exceeding 40mm. Then, saw the milled ingots to a certain size.

[0040] 4. Place the surface-treated ingot in a pusher-type or trolley-type heating furnace for heating. Set the heating temperature to 550℃ and the heating time to 6 hours; then change the heating temperature to 450℃ and the heating time to 5 hours. The metal exiting the furnace should be 445℃. The rolling speed is 1.6 m / s, and the number of rolling passes is pre-designed according to the thickness of the finished sheet to obtain the raw sheet.

[0041] 5. The raw material sheet prepared in step 4 is cut to length using a rolling mill with heavy or light shearing, and the length cutting error is controlled to be ≤100mm. Then, it is subjected to solution quenching treatment in a roller hearth furnace. The solution quenching process is as follows: constant temperature 540℃, heating time 30min, holding time 15min. After the holding time, the quenching treatment is automatically performed, and the quenching transfer time is 25s.

[0042] 6. Stretch the solution-quenched sheet by 1.2-1.4%.

[0043] 7. After stretching, the sheet will undergo aging treatment. The aging process is as follows: set the aging furnace to a constant temperature of 225℃, measure the lowest metal temperature to 195℃, then switch to a constant temperature of 205℃ and hold for 10 hours. The sheet should be removed from the furnace at a metal temperature of 205℃ for 10 hours.

[0044] After aging, the boards are precision sawn to obtain finished boards. Samples are taken for mechanical property testing, and electrical conductivity is tested on the surface of the finished boards. The properties and electrical conductivity are shown in Table 1.

[0045] Table 1 Mechanical properties of Al-Mg-Si0.5-T63 alloy

[0046]

[0047] As shown in Table 1, with the optimization of the solution quenching heat treatment process, increasing the solution temperature by 10℃ allows the strengthenable phase (such as Mg2Si) to fully dissolve into the aluminum matrix, forming a supersaturated solid solution. This prepares the aluminum for subsequent aging precipitation strengthening and provides a more sufficient precipitation driving force for subsequent aging, resulting in a "purer" matrix and higher electrical conductivity after aging. Ultimately, the yield strength and tensile strength of the plate are improved, the elongation is slightly reduced, and the electrical conductivity is increased.

Claims

1. A high-strength, high-conductivity aluminum alloy thick plate of Al-Mg-Si0.5 for electrical applications, characterized in that, The aluminum alloy thick plate is composed of 0.4%~0.8% Si, 0.4%~0.6% Fe, 0.15%~0.4% Cu, 0.04%~0.08% Mn, 0.8%~1.2% Mg, 0.15%~0.5% Cr, 0.04%~0.08% Zn, 0.04%~0.08% Ti, and the balance Al by mass fraction.

2. The high-strength, high-conductivity aluminum alloy thick plate for electrical applications according to claim 1, characterized in that, The aluminum alloy thick plate is composed of 0.53% Si, 0.47% Fe, 0.25% Cu, 0.06% Mn, 1.0% Mg, 0.35% Cr, 0.05% Zn, 0.06% Ti, and the balance Al by mass fraction.

3. The method for preparing a high-strength, high-conductivity Al-Mg-Si0.5 aluminum alloy thick plate for electrical applications as described in claim 1, characterized in that, The preparation method is as follows: I. Aluminum alloy thick plates are prepared according to the following chemical composition mass fraction ratios: Si 0.4%~0.8%, Fe 0.4%~0.6%, Cu 0.15%~0.4%, Mn 0.04%~0.08%, Mg 0.8%~1.2%, Cr 0.15%~0.5%, Zn 0.04%~0.08%, Ti 0.04%~0.08%, and the balance being Al. The raw materials are then melted at a temperature of 700℃~750℃ for 5h~7h to obtain aluminum alloy melt. II. A semi-continuous water-cooled casting method is used to cast aluminum alloy molten metal into ingots; 3. The ingot is surface treated and then heated at 530℃~570℃ for 5h~6h; the heating temperature is then changed to 430℃~470℃ for 3h~5h; the metal is then rolled at a furnace exit temperature of 400℃~440℃ to obtain the raw sheet. Fourth, the raw material sheet is cut, then subjected to solution quenching, stretched and then aged to obtain the finished sheet.

4. The method for preparing a high-strength, high-conductivity Al-Mg-Si0.5 aluminum alloy thick plate for electrical applications according to claim 3, characterized in that, The casting temperature in step two is 690℃~720℃, the casting speed is 40mm / min~50mm / min, the liquid level is 75mm~100mm, and the cooling water flow rate is 110M. 3 / h~180M 3 / h.

5. The method for preparing a high-strength, high-conductivity aluminum alloy thick plate for electrical applications according to claim 3, characterized in that, Step 3, surface treatment, involves milling the surface of the ingot, with a milling amount of 5mm to 30mm and a maximum milling amount of ≤40mm.

6. The method for preparing a high-strength, high-conductivity Al-Mg-Si0.5 aluminum alloy thick plate for electrical applications according to claim 3, characterized in that, In step three, the rolling speed is 1.2 m / s to 2.0 m / s.

7. The method for preparing a high-strength, high-conductivity Al-Mg-Si0.5 aluminum alloy thick plate for electrical applications according to claim 3, characterized in that, The solution quenching in step four is as follows: constant temperature 545~555℃, heating time 15min~30min, holding temperature 10min~15min, and then quenching treatment, with quenching transfer time of 15s~40s.

8. The method for preparing a high-strength, high-conductivity Al-Mg-Si0.5 aluminum alloy thick plate for electrical applications according to claim 3, characterized in that, The stretching amount in step four is 1.2~1.4%.

9. The method for preparing a high-strength, high-conductivity Al-Mg-Si0.5 aluminum alloy thick plate for electrical applications according to claim 3, characterized in that, The aging process in step four is as follows: set the aging furnace to a constant temperature of 225℃, measure the lowest metal temperature to 195℃, then switch to a constant temperature of 205℃ and hold for 10 hours; the metal temperature should be 190~210℃ / 10 hours before being removed from the furnace.

10. The method for preparing a high-strength, high-conductivity Al-Mg-Si0.5 aluminum alloy thick plate for electrical applications according to claim 3, characterized in that, The Al-Mg-Si0.5 high-strength, high-conductivity aluminum alloy thick plate for electrical applications meets the following requirements: tensile strength ≥175MPa, yield strength ≥132MPa, elongation ≥14%, and conductivity ≥55%IACS.

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