Manufacturing method of 7050 hub aluminum alloy die forging

Abstract

The invention relates to a manufacturing method of aluminum alloy die forgings, in particular to a manufacturing method of 7050 hub aluminum alloy die forgings. The invention aims to solve the problem that high strength and high toughness of the existing aluminum alloy plate are difficult to consider at the same time. The method comprises the following steps: 1, preparing an aluminum alloy cast ingot; 2, free forging; 3, mould pressing; 4, machining; 5, heat treatment; and 6, flaw detection. The aluminum alloy hub die forging manufactured through the method meets the standard requirement, the overall use performance of the hub is improved, the strength, abrasion resistance and other characteristics of the hub are improved, the service life of the hub is prolonged, and the requirement of the high-performance aluminum alloy hub die forging is met. The method is applied to the technical field of aluminum alloy.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a 7050 wheel hub aluminum alloy die forging. Background Art

[0002] With the development of modern industry, the performance requirements for vehicles are getting higher and higher. As a very important load-bearing component of the vehicle, the wheel hub is in a high-friction, high-strength and high-load working environment for a long time, and its quality has an impact on vehicle safety. Existing wheel hubs are mostly made of 2-series aluminum alloys such as 2A50, which is a medium-strength aluminum alloy with good plasticity but low strength. It is difficult to meet the use requirements of heavy vehicles. The wheel hub made of 7050 alloy die forgings has the characteristics of high structural strength, meets the new needs of vehicle development, and increases the service life of the wheel hub. This technology has a wide range of promotion and application value in the vehicle industry, plays an important role in improving the lightweight of vehicles, and also has good economic benefits. Summary of the invention

[0003] The purpose of the present invention is to solve the problem that the existing wheel hub has low performance strength and poor fracture toughness and cannot meet the development requirements, and to provide a method for manufacturing aluminum alloy die forgings.

[0004] The present invention provides a method for manufacturing a 7050 wheel hub aluminum alloy die forging, which is carried out according to the following steps:

[0005] 1. According to the mass percentage of elements in the aluminum alloy ingot: Si is ≤0.12%, Fe is ≤0.15%, Cu is 2.0% to 2.6%, Mn is ≤0.10%, Mg is 1.9% to 2.6%, Cr is ≤0.04%, Zn is 5.7% to 6.7%, Ti is ≤0.06%, Zr is 0.08% to 0.15%, single impurity is ≤0.05%, total impurity is ≤0.15% and the rest is Al, the ingot is heated at 380°C to 430°C, the holding time is 4 to 6 hours, and a blank is obtained;

[0006] 2. The blank obtained in step 1 is heated and then subjected to the first free forging, and then sawed and heated for the second free forging to obtain a forging;

[0007] 3. Lubricate and mold the forged piece obtained in step 2 three times at a forging temperature of 390°C to 460°C and a mold temperature of 400°C to 420°C, and then clean it;

[0008] 4. Use a boring machine to perform center drilling on the forging obtained in step 4;

[0009] 5. The forging obtained in step 4 is quenched and aged, thereby completing a method for manufacturing an aluminum alloy die forging.

[0010] Beneficial effects of the present invention: a 7050 aluminum alloy wheel hub die forging manufactured by the present invention adopts 7050 aluminum alloy to replace 2A50 to produce the wheel hub die forging, which not only meets the standard requirements, but also has a significant improvement in strength, the tensile strength can be increased by 20%, the yield strength can be increased by 50%, and the elongation can meet the standard requirements, thereby improving the overall performance of the wheel hub, improving the strength of the wheel hub, and increasing the service life of the wheel hub, meeting the requirements of high-performance 7050 aluminum alloy wheel hub die forgings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A is a three-dimensional diagram of the 7050 aluminum alloy wheel hub die forging of the present application;

[0012] Figure 2 This is the three-dimensional diagram B of the 7050 aluminum alloy wheel hub die forging of this application. DETAILED DESCRIPTION

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

[0014] Specific implementation method 1: This implementation method is a method for manufacturing a 7050 wheel hub aluminum alloy die forging, which is carried out according to the following steps:

[0015] 1. According to the mass percentage of elements in the aluminum alloy ingot: Si is ≤0.12%, Fe is ≤0.15%, Cu is 2.0% to 2.6%, Mn is ≤0.10%, Mg is 1.9% to 2.6%, Cr is ≤0.04%, Zn is 5.7% to 6.7%, Ti is ≤0.06%, Zr is 0.08% to 0.15%, single impurity is ≤0.05%, total impurity is ≤0.15% and the rest is Al, the ingot is heated at 380°C to 430°C, the holding time is 4 to 6 hours, and a blank is obtained;

[0016] 2. The blank obtained in step 1 is heated and then subjected to the first free forging, and then sawed and heated for the second free forging to obtain a forging;

[0017] 3. Lubricate and mold the forged piece obtained in step 2 three times at a forging temperature of 390°C to 460°C and a mold temperature of 400°C to 420°C, and then clean it;

[0018] 4. Use a boring machine to perform center drilling on the forging obtained in step 4;

[0019] 5. The forging obtained in step 4 is quenched and aged, thereby completing a method for manufacturing an aluminum alloy die forging.

[0020] Specific embodiment 2: This embodiment is different from specific embodiment 1 in that: in step 2, the blank is heated to 380°C to 420°C and kept warm for 4 to 5 hours, the flat anvil temperature is 350°C to 400°C during the first free forging, and the blank is forged into a die blank according to the forging process 6. The rest is the same as specific embodiment 1.

[0021] Specific implementation method three: This implementation method is different from specific implementation method one or two in that the six forging processes are upsetting → first drawing → first multi-directional forging → second drawing → second multi-directional forging → third drawing. The rest is the same as specific implementation method one or two.

[0022] Specific embodiment 4: This embodiment is different from specific embodiments 1 to 3 in that: the blank obtained after the first free forging in step 2 is sawn and then heated at a temperature of 380°C to 420°C and kept warm for 4 to 5 hours, the flat anvil temperature during the second free forging is required to be 350°C to 400°C, and the blank is forged according to the forging process 5. The rest is the same as specific embodiments 1 to 3.

[0023] Specific implementation mode 5: This implementation mode is different from specific implementation modes 1 to 4 in that the forging process 5 is upsetting → primary drawing → primary multi-directional forging → secondary drawing → secondary multi-directional forging. The rest is the same as specific implementation modes 1 to 4.

[0024] Specific implementation method 6: This implementation method is different from specific implementation methods 1 to 5 in that a 5000-ton hydraulic press is used for molding in step 3. The rest is the same as specific implementation methods 1 to 5.

[0025] Specific embodiment 7: This embodiment is different from specific embodiments 1 to 6 in that: the cleaning described in step 3 is: the forging to be washed is placed sideways in a stainless steel etching and washing special basket, and is etched and degreased in an alkaline bath of 15% to 20wt% NaOH at 50℃ to 70℃ for 10 to 20min, then the alkaline solution is washed in a cold water tank at room temperature, and then the alkaline solution is neutralized and washed in an acid tank of 30 to 40wt% HNO3 at room temperature for 5 to 8min, and then the acid solution is washed in a cold water tank at room temperature, and finally rinsed in a hot water tank at 50 to 70℃, and the process is completed. The rest is the same as specific embodiments 1 to 6.

[0026] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that the quenching temperature of the forging in step 5 is 460°C to 475°C, and when the metal temperature reaches the quenching temperature, the heat preservation is started for 90 to 150 minutes. The rest is the same as specific embodiments 1 to 7.

[0027] Specific embodiment 9: This embodiment is different from specific embodiments 1 to 8 in that the temperature of the water used for quenching is 30°C to 50°C; the quenching transfer time is ≤15 seconds, and the quenching basket is lifted and lowered 15 times in the water, and then lifted out of the water after staying in the water for 15 minutes. The rest is the same as specific embodiments 1 to 8.

[0028] Specific embodiment 10: This embodiment is different from specific embodiments 1 to 9 in that the temperature of single-stage aging is 135°C to 145°C, and when the metal temperature reaches the aging temperature, it is kept warm for 16 hours. Other aspects are the same as specific embodiments 1 to 9.

[0029] The following examples are used to verify the beneficial effects of the present invention:

[0030] Example 1

[0031] A method for manufacturing an aluminum alloy die forging is specifically carried out according to the following steps:

[0032] 1. According to the mass percentage of elements in the aluminum alloy ingot: Si is ≤0.12%, Fe is ≤0.15%, Cu is 2.0% to 2.6%, Mn is ≤0.10%, Mg is 1.9% to 2.6%, Cr is ≤0.04%, Zn is 5.7% to 6.7%, Ti is ≤0.06%, Zr is 0.08% to 0.15%, individual impurities are ≤0.05%, total impurities are ≤0.15% and the rest is Al, the aluminum alloy ingot is prepared, the heating temperature of the ingot is controlled to be 380° C. to 430° C., the holding time is 4 to 6 hours, and the prepared aluminum alloy ingot is a square body with a size of 420×900×900 mm, that is, a blank;

[0033] 2. Free forging of blanks required for forgings: Blank heating temperature is 380℃~420℃, and heat preservation is 4~5 hours. The temperature of flat anvil is required to be 350℃~400℃ during free forging. Blanks are forged according to six processes (i.e. upsetting → primary drawing → primary multi-square forging → secondary drawing → secondary multi-square forging → tertiary drawing);

[0034] 3. Second free forging of the blank required for forgings: The blank after forging is sawn first, and then the blank is heated to 380℃~420℃ and kept warm for 4~5 hours. The flat anvil temperature is required to be 350℃~400℃ during free forging. The blank is forged according to the five processes (i.e. upsetting → primary drawing → primary multi-square forging → secondary drawing → secondary multi-square forging);

[0035] 4. The forging obtained in step 2 is molded by a 5000-ton hydraulic press at a forging temperature of 390°C to 460°C and a mold temperature of 400°C to 420°C, and lubrication molding is performed three times;

[0036] 5. Place the forgings obtained in step 3 sideways in a stainless steel etching basket, and degrease them in an alkaline bath of 15% to 20wt% NaOH at 50℃ to 70℃ for 10 to 20min, then wash off the alkaline solution in a cold water tank at room temperature, and then neutralize and wash in an acid tank of 30 to 40wt% HNO3 at room temperature for 5 to 8min, and then wash off the acid solution in a cold water tank at room temperature, and finally rinse the parts in a hot water tank at 50 to 70℃, take them out and place them on a repair site with an aluminum pad on the ground for repair, and check and remove any defects in the forgings.

[0037] 6. Use a boring machine to perform center drilling machining on the forging obtained in step 4;

[0038] 7. Heat treat the forgings obtained in step 5. The die forgings are placed upright in the quenching basket to facilitate the flow of water in the inner cavity of the forgings. The test samples are placed in the quenching basket at the same time. The quenching temperature of the forgings is 460℃~475℃, the quenching holding time is 90~150 minutes based on the metal insulation, and the temperature of the water used for quenching is 30℃~50℃; the quenching transfer time is less than or equal to 15 seconds, and the quenching basket is lifted and lowered 15 times in the water, and then it can be lifted out of the water after staying in the water for 15 minutes. When punching the quenching furnace number, punch to the designated position and it must be clear. When installing the aging furnace, the material rack must be placed in a way that is conducive to the smooth circulation of the air so that it can be heated evenly and quickly. The temperature of the single-stage aging is 135℃~145℃, the metal is kept warm for 16h, and the total heating time is 16~20 hours;

[0039] 7. The forgings heat treated in step 6 are subjected to 100% A-level flaw detection according to GJB1580A flaw detection standard, and then the finished products are packaged, thus completing a method for manufacturing aluminum alloy die forgings.

[0040] Table 1 Mechanical properties of 7050 alloy wheel forgings

[0041]

[0042] Table 2 Mechanical properties of 2A50 alloy wheel forgings

[0043]

[0044] The wheel hub die forgings produced by 2A50 were used as a control group, and the mechanical properties of the aluminum alloy die forgings prepared in this embodiment and the wheel hub die forgings produced by 2A50 were tested. The results are shown in Tables 1 and 2. The use of 7050 aluminum alloy instead of 2A50 to produce wheel hub die forgings not only meets the standard requirements, but also has a significant improvement in strength. The tensile strength can be increased by 20%, the yield strength can be increased by 50%, and the elongation can meet the standard requirements, thereby improving the overall performance of the wheel hub, improving the strength of the wheel hub, and increasing the service life of the wheel hub, meeting the requirements of high-performance 7050 aluminum alloy wheel hub die forgings.

Claims

1. A method for manufacturing a 7050 wheel hub aluminum alloy die forging, characterized in that The method proceeds as follows:

1. According to the mass percentage of elements in the aluminum alloy ingot: Si is ≤0.12%, Fe is ≤0.15%, Cu is 2.0% to 2.6%, Mn is ≤0.10%, Mg is 1.9% to 2.6%, Cr is ≤0.04%, Zn is 5.7% to 6.7%, Ti is ≤0.06%, Zr is 0.08% to 0.15%, single impurity is ≤0.05%, total impurity is ≤0.15% and the rest is Al, the ingot is heated at 380°C to 430°C, the holding time is 4 to 6 hours, and a blank is obtained; 2. The blank obtained in step 1 is heated and then subjected to the first free forging, and then sawed and heated for the second free forging to obtain a forging; 3. Lubricate and mold the forged piece obtained in step 2 three times at a forging temperature of 390°C to 460°C and a mold temperature of 400°C to 420°C, and then clean it; 4. Use a boring machine to perform center drilling on the forging obtained in step 4; 5. The forging obtained in step 4 is quenched and aged, thereby completing a method for manufacturing an aluminum alloy die forging.

2. The method for manufacturing a 7050 wheel hub aluminum alloy die forging according to claim 1, characterized in that In step 2, the blank is heated to 380°C-420°C and kept warm for 4-5 hours. During the first free forging, the flat anvil temperature is 350°C-400°C. The blank is forged into a mold blank according to the six forging processes.

3. The method for manufacturing a 7050 wheel hub aluminum alloy die forging according to claim 2, characterized in that The six forging processes are upsetting → first drawing → first multi-directional forging → second drawing → second multi-directional forging → third drawing.

4. The method for manufacturing a 7050 wheel hub aluminum alloy die forging according to claim 1, characterized in that The blank obtained after the first free forging in step 2 is sawn and then heated at a temperature of 380°C to 420°C and kept warm for 4 to 5 hours. The flat anvil temperature is required to be 350°C to 400°C during the second free forging, and the blank is forged according to the five forging processes.

5. The method for manufacturing a 7050 wheel hub aluminum alloy die forging according to claim 4, characterized in that The five forging processes are upsetting → first drawing → first multi-directional forging → second drawing → second multi-directional forging.

6. The method for manufacturing a 7050 wheel hub aluminum alloy die forging according to claim 1, characterized in that In step three, a 5000-ton hydraulic press is used for molding.

7. The method for manufacturing a 7050 wheel hub aluminum alloy die forging according to claim 1, characterized in that The cleaning described in step three is as follows: the forgings to be washed are placed sideways in a stainless steel etching and washing basket, and are etched and degreased in an alkaline bath of 15% to 20wt% NaOH at 50°C to 70°C for 10 to 20 minutes, and then the alkaline solution is washed off in a cold water tank at room temperature, and then the alkaline solution is neutralized and washed in an acid tank of 30 to 40wt% HNO3 at room temperature for 5 to 8 minutes, and then the acid solution is washed off in a cold water tank at room temperature, and finally rinsed in a hot water tank at 50 to 70°C.

8. The method for manufacturing a 7050 wheel hub aluminum alloy die forging according to claim 1, characterized in that Step 5: The quenching temperature of the forging is 460°C to 475°C. When the metal temperature reaches the quenching temperature, the heat preservation begins, and the heat preservation time is 90 to 150 minutes.

9. The method for manufacturing a 7050 wheel hub aluminum alloy die forging according to claim 1, characterized in that The temperature of the water used for quenching is 30℃~50℃; the quenching transfer time is ≤15 seconds, and the quenching basket is lifted and lowered 15 times in the water, and then hung out of the water after staying in the water for 15 minutes.

10. The method for manufacturing a 7050 wheel hub aluminum alloy die forging according to claim 1, characterized in that The temperature of single-stage aging is 135℃~145℃. When the metal temperature reaches the aging temperature, it is kept warm for 16 hours.

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