Production method of 7-series aluminum alloy backward extrusion automobile bar

Abstract

The invention provides a 7-series aluminum alloy backward extrusion automobile bar production method which comprises the steps of burdening, casting, cast bar homogenization, extrusion, bar quenching, stretching and cutting, aging treatment and the like, a first-stage homogenization system and a second-stage homogenization system are adopted in cast bar homogenization, in the extrusion process, a backward extrusion die comprises a rear chamber and a working belt which are connected in sequence, and the working belt is provided with a first-stage homogenization system, a second-stage homogenization system and a second-stage homogenization system. The rear chamber comprises a first conical area, a cylindrical area and a second conical area which are sequentially connected. By optimizing the alloy components, improving the casting process, adjusting the structural design of the die and accurately controlling the extrusion process parameters, the continuous online quenching production is realized, the surface quality defects are obviously reduced, the rejection rate and the production cost are reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy processing technology, and specifically discloses a production method of 7 series aluminum alloy reverse extrusion automobile bar. Background Art

[0002] With the development of the automobile industry, the role and importance of aluminum alloy extruded bars in automobile manufacturing have become increasingly prominent. As a lightweight and high-strength material, 7 series aluminum extruded bars are also suitable for the automobile industry and are used to manufacture automobile parts, such as body structures, frames, engine parts, gearbox parts, etc. 7 series aluminum extruded bars can provide higher strength and rigidity, while reducing vehicle weight, improving fuel economy and handling performance. The role and importance of 7 series aluminum alloys in automobile manufacturing cannot be ignored. As a representative of ultra-high-strength aluminum alloys, 7 series aluminum alloys have excellent comprehensive properties, can optimize the forging workpiece structure, and reduce organizational defects. Due to the high deformation resistance of 7 series aluminum alloys, slow extrusion speed, and susceptibility to coarse grains and surface defects, conventional production cannot achieve online quenching and extrusion, which greatly reduces production efficiency.

[0003] Reverse extrusion is one of the methods for producing aluminum alloy bars. When reverse extrusion is used, the metal flows evenly, there is no friction, the required extrusion force is small, and alloys with higher deformation resistance can be extruded. The microstructure and mechanical properties of the extruded product length are basically the same, and waste such as residual pressure is significantly reduced, and the yield rate is high. Although reverse extrusion has the above advantages, it also has its disadvantages. During reverse extrusion production, a dead zone of the billet will be generated on the surface of the extruded bar. The dead zone of the billet is easy to participate in the flow, and defects such as stratification, bubbles, and peeling are easy to form on the surface of the product, resulting in a decrease in the surface quality of the product. In addition, due to the structural reasons of the reverse extrusion equipment, continuous production cannot be achieved, which has a great impact on production efficiency. In view of the above problems, it is very necessary to study and design a new method for producing 7 series aluminum alloy reverse extrusion automobile bars to overcome the problems existing in the existing reverse extrusion production of automobile bars. Summary of the invention

[0004] The present invention proposes a 7 series aluminum alloy reverse extrusion automobile bar production method to solve the problems faced in the existing automobile bar reverse extrusion production process, such as the dead zone of the billet participating in the flow leading to a decrease in product surface quality and the inability to produce continuously during the reverse extrusion process.

[0005] The present invention provides a method for producing a 7 series aluminum alloy reverse extrusion automobile bar, comprising the following steps:

[0006] S1. Ingredients: Prepare aluminum alloy raw materials according to the following weight ratios: Si: ≤0.08%, Fe: ≤0.50%, Cu: 2.5%~2.55%, Mn: ≤0.07%, Mg: 2.4%~2.6%, Cr: 0.05%~0.1%, Zn: 6.8%~7.0%, Ti: 0.07%~0.1%, Zr: 0.15%~0.2%, Sc: 0.17%~0.2%, single impurity ≤0.05%, total impurity ≤0.15%, and the balance is Al;

[0007] S2. Casting: The aluminum alloy raw material prepared in step S1 is placed in a smelting furnace for casting to obtain a cast rod;

[0008] S3. Homogenization of cast rods: subjecting the cast rods obtained in step S2 to a primary homogenization system and a secondary homogenization system to obtain round ingots, wherein the temperature of the primary homogenization annealing system is 305-315°C, and the holding time is 4-8 hours; the temperature of the secondary homogenization annealing system is 460-470°C, and the holding time is 20-23 hours;

[0009] S4. Extrusion: placing the round ingot in step S3 into a reverse extrusion device for extrusion to obtain a rod, wherein the reverse extrusion die comprises a back chamber and a working belt connected in sequence, the back chamber comprises a first conical zone, a cylindrical zone and a second conical zone connected in sequence, the inlet diameter of the first conical zone is greater than the outlet diameter, the outlet diameter of the first conical zone is equal to the diameter of the cylindrical zone, the inlet diameter of the second conical zone is equal to the diameter of the cylindrical zone, the inlet diameter of the second conical zone is greater than the outlet diameter, the second conical zone is connected to the working belt, the outlet diameter of the second conical zone is equal to the diameter of the working belt, the round ingot is heated by a stepwise heating method, the heating temperature of the head end of the round ingot is 390-410°C, the heating temperature of the tail end is 370-390°C, the temperature of the extrusion barrel is 390-420°C, the heating temperature of the reverse extrusion die is 400-450°C, and the product speed is 3.5m / min-4m / min;

[0010] S5. Quenching, stretching and cutting of the rod: quenching the rod obtained in step S4 to obtain a quenched rod, stretching and straightening the quenched rod and cutting it into a specified length;

[0011] S6. Aging treatment: The rod cut in step S5 is subjected to aging treatment at an aging temperature of 157 to 163° C. for 14 h to obtain an automobile rod.

[0012] According to a method for producing 7 series aluminum alloy reverse extrusion automobile bars in some embodiments of the present application, in step S1, the ingredients are Si: ≤0.05%, Fe: ≤0.39%, Cu: 2.52%~2.54%, Mn: ≤0.05%, Mg: 2.53%~2.58%, Cr: 0.07%~0.09%, Zn: 6.88%~6.95%, Ti: 0.08%~0.09%, Zr: 0.17%~0.19%, Sc: 0.17%~0.18%, single impurity ≤0.05%, total impurities ≤0.15%, and the balance is Al.

[0013] According to a method for producing 7 series aluminum alloy reverse extrusion automobile bars in some embodiments of the present application, in step S2, during melting and casting, a semi-continuous casting method is adopted, foam ceramic filtration is adopted during the melting and casting process, Al-Ti-B wire is used to refine the grains, the melting temperature is 690℃-750℃, the refining temperature is 720℃-740℃, the refining agent dosage is 2.8kg / TAl, the waste addition amount is ≤10%, and the hydrogen element is 0.15ml / 100g.

[0014] According to a method for producing a 7-series aluminum alloy reverse extrusion automobile bar in some embodiments of the present application, in step S3, the temperature of the primary homogenization annealing system is 310°C, and the holding time is 6.5 hours; the temperature of the secondary homogenization annealing system is 470°C, and the holding time is 22 hours.

[0015] According to a method for producing a 7-series aluminum alloy reverse extrusion automobile bar in some embodiments of the present application, in step S3, the round ingot is a Φ247 mm round ingot.

[0016] According to a method for producing 7 series aluminum alloy reverse extrusion automobile bars in some embodiments of the present application, in step S4, the angle between the side wall of the first tapered zone and the axis is 68° to 71°, and the angle between the side wall of the second tapered zone and the axis is 56.5° to 60°.

[0017] According to a method for producing 7 series aluminum alloy reverse extrusion automobile bars in some embodiments of the present application, in step S4, the distance from the entrance to the exit of the first conical zone is 25 mm; the distance from the entrance to the exit of the cylindrical zone is 25 mm; and the distance from the entrance to the exit of the second conical zone is 15 mm.

[0018] According to a method for producing a 7-series aluminum alloy reverse extrusion automobile bar in some embodiments of the present application, in step S5, the cooling method in the quenching is water cooling, the quenching zone temperature is 420-450°C, and the temperature out of the quenching zone is ≤50°C.

[0019] According to a method for producing 7 series aluminum alloy reverse extrusion automobile bars in some embodiments of the present application, in step S5, the diameter of the cylindrical area is 81 mm.

[0020] According to a method for producing a 7-series aluminum alloy reverse extrusion automobile bar in some embodiments of the present application, in step S5, the stretching rate in the stretching and straightening treatment is 0.5%-1%.

[0021] The present invention proposes a 7 series aluminum alloy reverse extrusion automobile bar production method, which realizes continuous online quenching production and significantly reduces surface quality defects by optimizing alloy composition, improving melting and casting process, adjusting mold structure design, and accurately controlling extrusion process parameters. The present invention effectively eliminates segregation in round ingots through a primary homogenization system and a secondary homogenization system, regulates the size and distribution of precipitated phases in round ingots, thereby greatly improving the strength and recrystallization temperature of the alloy, reducing the deformation resistance of round ingots, and increasing extrudability. It can ensure the performance of the produced automobile bar while improving the alloy fluidity and improving the surface quality of the produced automobile bar; the present invention adopts a reverse extrusion die with a first tapered area and a second tapered area to reduce the dead zone metal volume, prevent the dead zone metal from flowing to the surface of the automobile bar to form defects such as stratification, bubbles, and peeling, and improve the surface quality of the automobile bar, and the reverse extrusion die with a first tapered area and a second tapered area can reduce the extrusion force. In addition, the reverse extrusion die with a first tapered area and a second tapered area can increase the aluminum storage amount of the die to realize continuous extrusion production, reduce the scrap rate and production cost, and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a process for producing a 7 series aluminum alloy reverse extrusion automobile bar in the present invention;

[0023] Figure 2 The cross-sectional structural intention of the extrusion die of the present invention;

[0024] Figure 3 The top view of the extrusion die of the present invention is intended;

[0025] Figure 4 This is a high-magnification microstructure test image of the automobile rod produced in Example 3 of the present invention;

[0026] Figure 5 This is a high-magnification microstructure test image of the automobile rod produced in Example 4 of the present invention;

[0027] Figure 6 This is a high-magnification microstructure test image of the automobile rod produced in Example 5 of the present invention;

[0028] Figure 7 This is a high-magnification microstructure test image of the automobile rod produced in Example 6 of the present invention;

[0029] Figure 8 This is a high-magnification microstructure test image of the automobile rod produced in Example 7 of the present invention;

[0030] Fig. 9 This is a high-magnification microstructure test image of the automobile rod produced in Example 8 of the present invention;

[0031] Fig.10 This is a high-magnification microstructure test image of the automobile rod produced in Example 9 of the present invention;

[0032] Fig.11 This is a high-magnification microstructure test image of the automobile rod produced in Example 10 of the present invention;

[0033] Fig.12 This is a high-magnification microstructure test image of the automobile rod produced in Example 11 of the present invention;

[0034] Fig.13 This is a high-magnification microstructure test image of the automobile rod produced in Comparative Example 2 of the present invention.

[0035] In the figure: 1, rear chamber, 1-1, first conical area, 1-2, cylindrical area, 1-3, second conical area, 2, working zone. DETAILED DESCRIPTION

[0036] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0037] Embodiment 1, this embodiment provides a method for producing a 7 series aluminum alloy reverse extrusion automobile bar, such as Figure 1 As shown, the following steps are included:

[0038] S1. Ingredients: Prepare aluminum alloy raw materials according to the following weight ratios: Si: ≤0.08%, Fe: ≤0.50%, Cu: 2.5%~2.55%, Mn: ≤0.07%, Mg: 2.4%~2.6%, Cr: 0.05%~0.1%, Zn: 6.8%~7.0%, Ti: 0.07%~0.1%, Zr: 0.15%~0.2%, Sc: 0.17%~0.2%, single impurity ≤0.05%, total impurity ≤0.15%, and the balance is Al;

[0039] S2. Casting: The aluminum alloy raw material prepared in step S1 is placed in a smelting furnace for casting to obtain a cast rod;

[0040] S3. Homogenization of cast rods: The cast rods obtained in step S2 are subjected to a primary homogenization system and a secondary homogenization system to obtain round ingots, wherein the primary homogenization annealing system has a temperature of 305 to 315°C and a holding time of 4 to 8 hours; the secondary homogenization annealing system has a temperature of 460 to 470°C and a holding time of 20 to 23 hours;

[0041] S4. Extrusion: placing the round ingot in step S3 into a reverse extrusion device for extrusion to obtain a rod, wherein the reverse extrusion die comprises a rear chamber 1 and a working belt 2 connected in sequence, the rear chamber 1 comprises a first conical zone 1-1, a cylindrical zone 1-2 and a second conical zone 1-3 connected in sequence, the inlet diameter of the first conical zone 1-1 is greater than the outlet diameter, the outlet diameter of the first conical zone 1-1 is equal to the diameter of the cylindrical zone 1-2, the inlet diameter of the second conical zone 1-3 is equal to the diameter of the cylindrical zone 1-2, The inlet diameter of the second tapered zone 1-3 is larger than the outlet diameter, the second tapered zone 1-3 is connected to the working belt 2, the outlet diameter of the second tapered zone 1-3 is equal to the diameter of the working belt 2, the round ingot is heated by a step-by-step heating method, the heating temperature of the head end of the round ingot is 390-410°C, the heating temperature of the tail end is 370-390°C, the temperature of the extrusion barrel is 390-420°C, the heating temperature of the reverse extrusion die is 400-450°C, and the product speed is 3.5m / min-4m / min;

[0042] S5. Quenching, stretching and cutting of the rod: quenching the rod obtained in step S4 to obtain a quenched rod, stretching and straightening the quenched rod and cutting it into a specified length;

[0043] S6. Aging treatment: The rod cut in step S5 is subjected to aging treatment at an aging temperature of 157 to 163° C. for 14 h to obtain an automobile rod.

[0044] Embodiment 2: This embodiment provides a method for producing a 7 series aluminum alloy reverse extrusion automobile bar, comprising the following steps:

[0045] S1. Ingredients: Prepare aluminum alloy raw materials according to the following weight ratios: Si: ≤0.08%, Fe: ≤0.50%, Cu: 2.5%~2.55%, Mn: ≤0.07%, Mg: 2.4%~2.6%, Cr: 0.05%~0.1%, Zn: 6.8%~7.0%, Ti: 0.07%~0.1%, Zr: 0.15%~0.2%, Sc: 0.17%~0.2%, single impurity ≤0.05%, total impurity ≤0.15%, balance Al; In Al-Zn-Mg-Cu alloy, Zn and Mg are the main strengthening elements, adding Cu can improve the corrosion resistance of the alloy, but the Zn content should be controlled not to exceed 7%, otherwise the fracture toughness, welding and corrosion resistance of the alloy will deteriorate. In addition, when the Mg content exceeds the amount required to form MgZn2, it can play a supplementary role in alloy strengthening. Zr has low quenching sensitivity and has good hardenability and weldability of the alloy. Adding trace element Sc and Zr to form Al3 (Sc, Zr) particles can significantly improve the grain refinement effect, increase the recrystallization temperature, and refine the grains;

[0046] As a preferred embodiment of the present invention, specifically, the ingredients may be Si: ≤0.05%, Fe: ≤0.39%, Cu: 2.52% to 2.54%, Mn: ≤0.05%, Mg: 2.53% to 2.58%, Cr: 0.07% to 0.09%, Zn: 6.88% to 6.95%, Ti: 0.08% to 0.09%, Zr: 0.17% to 0.19%, Sc: 0.17% to 0.18%, single impurity ≤0.05%, total impurity ≤0.15%, and the balance is Al;

[0047] S2. Casting: The aluminum alloy raw material prepared in step S1 is placed in a smelting furnace for casting to obtain a cast rod;

[0048] As a preferred embodiment of the present invention, in particular, during the melting and casting, a semi-continuous casting method is used for melting and casting, foam ceramics are used for filtration during the melting and casting process, Al-Ti-B wire is used for grain refinement, the melting temperature is 690°C-750°C, the refining temperature is 720°C-740°C, the amount of refining agent is 2.8kg / TAl, the amount of waste added is ≤10%, and the hydrogen element is 0.15ml / 100g;

[0049] S3. Homogenization of cast rods: The cast rods obtained in step S2 are subjected to a primary homogenization system and a secondary homogenization system to obtain round ingots, wherein the temperature of the primary homogenization annealing system is 305-315°C, and the holding time is 4-8 hours; the temperature of the secondary homogenization annealing system is 460-470°C, and the holding time is 20-23 hours; by setting the primary homogenization system and the secondary homogenization system, the segregation in the round ingot can be effectively eliminated, and the size and distribution of the precipitated phase in the round ingot can be regulated, thereby greatly improving the strength and recrystallization temperature of the alloy, reducing the deformation resistance of the round ingot, and increasing the extrudability, which can ensure the performance of the produced automobile rods while improving the alloy fluidity and the surface quality of the produced automobile rods;

[0050] As a preferred embodiment of the present invention, specifically, the temperature of the primary homogenization annealing system is 310° C., and the holding time is 6.5 hours; the temperature of the secondary homogenization annealing system is 470° C., and the holding time is 22 hours; the obtained round ingot can be a Φ247 mm round ingot;

[0051] S4. Extrusion: The round ingot in step S3 is placed in a reverse extrusion device for extrusion to obtain a rod, wherein the reverse extrusion die is as follows Figure 2 and Figure 3 As shown, the reverse extrusion die includes a back chamber 1 and a working belt 2 connected in sequence, the back chamber 1 includes a first conical zone 1-1, a cylindrical zone 1-2 and a second conical zone 1-3 connected in sequence, the inlet diameter of the first conical zone 1-1 is larger than the outlet diameter, the outlet diameter of the first conical zone 1-1 is equal to the diameter of the cylindrical zone 1-2, the inlet diameter of the second conical zone 1-3 is equal to the diameter of the cylindrical zone 1-2, the inlet diameter of the second conical zone 1-3 is larger than the outlet diameter, the second conical zone 1-3 is connected to the working belt 2, the outlet diameter of the second conical zone 1-3 is equal to the diameter of the working belt 2, and the heating is carried out by a step-by-step heating method. Round ingot, the heating temperature of the head end of the round ingot is 390-410℃, the heating temperature of the tail end is 370-390℃, the temperature of the extrusion barrel is 390-420℃, the heating temperature of the reverse extrusion die is 400-450℃, and the product speed is 3.5m / min-4m / min; the conventional bar extrusion flat die is designed as a concave die angle structure, which reduces the die angle compared to the conventional die, improves the uniformity of metal flow, reduces the die angle, and reduces the dead zone volume. The metal in the dead zone flows to the surface of the product to form layers, bubbles, peeling and other defects, thereby improving the surface quality of the extruded bar and reducing the extrusion force. At the same time, increasing the first tapered area 1-1 and the second tapered area 1-3 can increase the amount of aluminum stored in the mold to prevent the mold from storing too little aluminum, resulting in inability to continuously extrude production. After the extrusion of the aluminum alloy round ingot is completed, this embodiment will retain the blank in the concave die and weld it with the next ingot for continuous online production, thereby improving production efficiency;

[0052] As a preferred embodiment of the present invention, specifically, the angle between the side wall of the first tapered zone 1-1 and the axis can be 68° to 71°, and the angle between the side wall of the second tapered zone 1-3 and the axis can be 56.5° to 60°; the distance from the entrance to the exit of the first tapered zone 1-1 can be 25 mm; the distance from the entrance to the exit of the cylindrical zone 1-2 can be 25 mm; the distance from the entrance to the exit of the second tapered zone 1-3 can be 15 mm; the diameter of the cylindrical zone 1-2 can be 81 mm, and an automotive bar with a diameter of 81 mm is produced;

[0053] S5. Quenching, stretching and cutting of the rod: quenching the rod obtained in step S4 to obtain a quenched rod, stretching and straightening the quenched rod and cutting it into a specified length;

[0054] As a preferred embodiment of the present invention, specifically, the cooling method in quenching is water cooling, the temperature of the quenching zone is 420-450°C, and the temperature out of the quenching zone is ≤50°C; in the stretching straightening treatment, the stretching rate is 0.5%-1%;

[0055] S6 aging treatment: The rod cut in step S5 was subjected to aging treatment at an aging temperature of 157 to 163 ° C for 14 hours to obtain an automotive rod;

[0056] As a preferred embodiment of this embodiment, specifically, the diameter of the automobile rod is 81 mm.

[0057] Embodiment 3, this embodiment provides a method for producing a 7 series aluminum alloy reverse extrusion automobile bar, which specifically comprises the following steps:

[0058] S1. Ingredients: Prepare aluminum alloy raw materials according to the following weight ratios: Si: 0.07%, Fe: 0.13%, Cu: 2.52%, Mn: 0.05%, Mg: 2.49%, Cr: 0.06%, Zn: 6.88%, Ti: 0.08%, Zr: 0.16%, Sc: 0.18%, single impurity: 0.05%, and the balance is Al;

[0059] S2. Melting and casting: Put the aluminum alloy raw material prepared in step S1 into a smelting furnace for melting and casting to obtain a cast rod. During the melting and casting, a semi-continuous casting method is used for melting and casting. Foam ceramics are used for filtration during the melting and casting process, and Al-Ti-B wire is used for grain refinement. The melting temperature is 690℃-750℃, the refining temperature is 720℃-740℃, the refining agent dosage is 2.8kg / TAl, the waste addition amount is ≤10%, and the hydrogen element is 0.15ml / 100g. The slag content of the ingot meets the secondary requirements in GB / T32186-2015;

[0060] S3. Homogenization of cast rods: The cast rods obtained in step S2 were subjected to a primary homogenization system and a secondary homogenization system to obtain round ingots. The primary homogenization annealing system was 310 ° C and the holding time was 6.5 hours; the secondary homogenization annealing system was 470 ° C and the holding time was 22 hours;

[0061] S4. Extrusion: placing the round ingot in step S3 into a reverse extrusion device for extrusion to obtain a rod, the reverse extrusion die comprises a first tapered area 1-1, a cylindrical area 1-2, a second tapered area 1-3 and a working zone 2 connected in sequence, the angle between the side wall of the first tapered area 1-1 and the axis is 69.3°, the angle between the side wall of the second tapered area 1-3 and the axis is 58.5°, the round ingot is heated by a stepwise heating method, and a Φ81mm rod is produced by a 20MN reverse aluminum extruder, the round ingot is selected as a Φ247mm round ingot, the heating temperature of the head end of the round ingot is 405°C, the heating temperature of the tail end is 385°C, the heating temperature of the reverse extrusion die is 440°C, and the temperature of the extrusion barrel is 403°C;

[0062] S5. Quenching, stretching and cutting of bars: quenching the bars obtained in step S4, wherein the cooling method in the quenching is water cooling, the quenching temperature is 443°C, and the temperature out of the quenching zone is ≤50°C. The quenched bars are stretched and straightened, and the stretching rate is 0.5%-1%. The stretched and straightened bars are cut into a specified length;

[0063] S6. Aging treatment: The rod cut in step S5 is subjected to aging treatment at an aging temperature of 160° C. for 14 h to obtain an automobile rod.

[0064] Mechanical properties test: Testing equipment: AG-X 100KN electronic universal testing machine. Test method: GB / T16865-2013 Specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products. Four pieces were randomly selected from the produced automotive bars and numbered. The results are shown in Table 1:

[0065] Table 1 Mechanical properties results

[0066]

[0067] High-magnification tissue inspection: Test equipment: AXIO universal research-grade inverted material microscope. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy product tissue inspection method Part 1: Microstructure inspection method. One piece was randomly selected from the produced automobile bars for testing. The test results are shown in Table 2 and Figure 4 shown.

[0068] Table 2 High magnification microstructure

[0069]

[0070] Macroscopic test: alkaline corrosive liquid for testing equipment. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy product structure inspection method Part 2: Macroscopic structure inspection method. Four pieces were randomly selected from the produced automobile bars and numbered. The results are shown in Table 3:

[0071] Table 3 Macroscopic tissue test

[0072]

[0073] Example 4. This example provides an extrusion production method for a new energy vehicle water-cooling plate aluminum profile. The reverse extrusion equipment and reverse extrusion die used in Example 3 are used for extrusion, and the experimental steps and conditions are the same as those in Example 3. The difference from Example 3 is that in this example, the angle between the side wall of the first tapered zone 1-1 and the axis is 68° and the angle between the side wall of the second tapered zone 1-3 and the axis is 56.5°. The test results of the automobile bars produced in this example are as follows:

[0074] Mechanical properties test: Testing equipment: AG-X 100KN electronic universal testing machine. Test method: GB / T16865-2013 Specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products. Four pieces were randomly selected from the produced automotive bars and numbered. The results are shown in Table 4:

[0075] Table 4 Mechanical properties results

[0076]

[0077] High-magnification tissue inspection: Test equipment: AXIO universal research-grade inverted material microscope. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy product tissue inspection method Part 1: Microstructure inspection method. One piece was randomly selected from the produced automobile bars for testing. The test results are shown in Table 5 and Figure 5 shown.

[0078] Table 5 High magnification microstructure

[0079]

[0080] Macroscopic test: test equipment alkaline corrosive liquid. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy product structure inspection method Part 2: Macroscopic structure inspection method. Four pieces were randomly selected from the produced automobile bars and numbered. The results are shown in Table 6:

[0081] Table 6 Macrostructure test

[0082]

[0083] Example 5. This example provides a method for extruding an aluminum profile for a water-cooling plate of a new energy vehicle. The reverse extrusion equipment and reverse extrusion die used in Example 3 are used for extrusion, and the experimental steps and conditions are the same as those in Example 3. The difference from Example 3 is that in this example, the angle between the side wall of the first tapered zone 1-1 and the axis is 68° and the angle between the side wall of the second tapered zone 1-3 and the axis is 60°. The test results of the automobile bars produced in this example are as follows:

[0084] Mechanical properties test: Testing equipment: AG-X 100KN electronic universal testing machine. Test method: GB / T16865-2013 Specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products. Four pieces were randomly selected from the produced automotive bars and numbered. The results are shown in Table 7:

[0085] Table 7 Mechanical properties results

[0086]

[0087] High-magnification tissue inspection: Test equipment: AXIO universal research-grade inverted material microscope. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy product tissue inspection method Part 1: Microstructure inspection method. One piece was randomly selected from the produced automobile bars for testing. The test results are shown in Table 8 and Figure 6 shown.

[0088] Table 8 High magnification microstructure

[0089]

[0090] Macroscopic test: alkaline corrosive liquid for testing equipment. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy product structure inspection method Part 2: Macroscopic structure inspection method. Four pieces were randomly selected from the produced automobile bars and numbered. The results are shown in Table 9:

[0091] Table 9 Macrostructure test

[0092]

[0093] Example 6. This example provides an extrusion production method for a new energy vehicle water-cooling plate aluminum profile. The reverse extrusion equipment and reverse extrusion die used in Example 3 are used for extrusion, and the experimental steps and conditions are the same as those in Example 3. The difference from Example 3 is that in this example, the angle between the side wall of the first tapered zone 1-1 and the axis is 71° and the angle between the side wall of the second tapered zone 1-3 and the axis is 56.5°. The test results of the automobile bars produced in this example are as follows:

[0094] Mechanical properties test: Testing equipment: AG-X 100KN electronic universal testing machine. Test method: GB / T16865-2013 Specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products. Four pieces were randomly selected from the produced automotive bars and numbered. The results are shown in Table 10:

[0095] Table 10 Mechanical properties results

[0096]

[0097] High-magnification tissue inspection: Test equipment: AXIO universal research-grade inverted material microscope. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy product tissue inspection method Part 1: Microstructure inspection method. One piece was randomly selected from the produced automobile bars for testing. The test results are shown in Table 11 and Figure 7 shown.

[0098] Table 11 High magnification microstructure

[0099]

[0100] Macroscopic test: alkaline corrosive liquid for testing equipment. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy product structure inspection method Part 2: Macroscopic structure inspection method. Four pieces were randomly selected from the produced automobile bars and numbered. The results are shown in Table 12:

[0101] Table 12 Macroscopic tissue test

[0102]

[0103] Example 7. This example provides an extrusion production method for a new energy vehicle water-cooling plate aluminum profile. The reverse extrusion equipment and reverse extrusion die used in Example 3 are used for extrusion, and the experimental steps and conditions are the same as those in Example 3. The difference from Example 3 is that in this example, the angle between the side wall of the first tapered zone 1-1 and the axis is 71° and the angle between the side wall of the second tapered zone 1-3 and the axis is 60°. The test results of the automobile bars produced in this example are as follows:

[0104] Mechanical properties test: Testing equipment: AG-X 100KN electronic universal testing machine. Test method: GB / T16865-2013 Specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products. Four pieces were randomly selected from the produced automotive bars and numbered. The results are shown in Table 13:

[0105] Table 13 Mechanical properties results

[0106]

[0107] High-magnification tissue inspection: Test equipment: AXIO universal research-grade inverted material microscope. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy product tissue inspection method Part 1: Microstructure inspection method. A piece of automobile bar produced was randomly selected for testing. The test results are shown in Table 14 and Figure 8 shown.

[0108] Table 14 High magnification microstructure

[0109]

[0110] Macroscopic test: alkaline corrosive liquid for testing equipment. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy product structure inspection method Part 2: Macroscopic structure inspection method. Four pieces were randomly selected from the produced automobile bars and numbered. The results are shown in Table 15:

[0111] Table 15 Macroscopic tissue test

[0112]

[0113] Example 8. This example provides a method for extruding aluminum profiles for water-cooling plates of new energy vehicles. The reverse extrusion equipment and reverse extrusion die used in Example 3 are used for extrusion, and the experimental steps and conditions are the same as those in Example 3. The difference from Example 3 is that in this example, the product speed is 3.5 m / min. The test results of the automobile bars produced in this example are as follows:

[0114] Mechanical properties test: Testing equipment: AG-X 100KN electronic universal testing machine. Test method: GB / T16865-2013 Specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products. Four pieces were randomly selected from the produced automotive bars and numbered. The results are shown in Table 16:

[0115] Table 16 Mechanical properties results

[0116]

[0117] High-magnification tissue inspection: Test equipment: AXIO universal research-grade inverted material microscope. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy product tissue inspection method Part 1: Microstructure inspection method. One piece was randomly selected from the produced automobile bars for testing. The test results are shown in Table 17 and Fig. 9 shown.

[0118] Table 17 High magnification microstructure

[0119]

[0120] Macroscopic test: test equipment alkaline corrosive liquid. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy product structure inspection method Part 2: Macroscopic structure inspection method. Four pieces were randomly selected from the produced automobile bars and numbered. The results are shown in Table 18:

[0121] Table 18 Macrostructure Test

[0122]

[0123] Example 9. This example provides a method for extruding aluminum profiles for water-cooling plates of new energy vehicles. The reverse extrusion equipment and reverse extrusion die used in Example 3 are used for extrusion, and the experimental steps and conditions are the same as those in Example 3. The difference from Example 3 is that in this example, the product speed is 4 m / min. The test results of the automobile bars produced in this example are as follows:

[0124] Mechanical properties test: Testing equipment: AG-X 100KN electronic universal testing machine. Test method: GB / T16865-2013 Specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products. Four pieces were randomly selected from the produced automotive bars and numbered. The results are shown in Table 19:

[0125] Table 19 Mechanical properties results

[0126]

[0127] High-magnification tissue inspection: Test equipment: AXIO universal research-grade inverted material microscope. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy product tissue inspection method Part 1: Microstructure inspection method. One piece was randomly selected from the produced automobile bars for testing. The test results are shown in Table 20 and Fig.10 shown.

[0128] Table 20 High magnification microstructure

[0129]

[0130] Macroscopic test: alkaline corrosive liquid for testing equipment. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy product structure inspection method Part 2: Macroscopic structure inspection method. Four pieces were randomly selected from the produced automobile bars and numbered. The results are shown in Table 21:

[0131] Table 21 Macroscopic tissue test

[0132]

[0133] Example 10. This example provides an extrusion production method for aluminum profiles for water-cooling plates for new energy vehicles. The reverse extrusion equipment and reverse extrusion die used in Example 3 are used for extrusion, and the experimental steps and conditions are the same as those in Example 3. The difference from Example 3 is that in this example, the ingredients are: Si: ≤0.08%, Fe: ≤0.50%, Cu: 2.5%, Mn: ≤0.07%, Mg: 2.4%, Cr: 0.05%, Zn: 6.8%, Ti: 0.07%, Zr: 0.15%, Sc: 0.17%. The test results of the automobile bars produced in this example are as follows:

[0134] Mechanical properties test: Testing equipment: AG-X 100KN electronic universal testing machine. Test method: GB / T16865-2013 Specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products. Four pieces were randomly selected from the produced automotive bars and numbered. The results are shown in Table 22:

[0135] Table 22 Mechanical properties results

[0136]

[0137] High-magnification tissue inspection: Test equipment: AXIO universal research-grade inverted material microscope. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy product tissue inspection method Part 1: Microstructure inspection method. One piece was randomly selected from the produced automobile bars for testing. The test results are shown in Table 23 and Fig.11 shown.

[0138] Table 23 High magnification microstructure

[0139]

[0140] Macroscopic test: alkaline corrosive liquid for testing equipment. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy product structure inspection method Part 2: Macroscopic structure inspection method. Four pieces were randomly selected from the produced automobile bars and numbered. The results are shown in Table 24:

[0141] Table 24 Macroscopic tissue test

[0142]

[0143] Example 11. This example provides a method for extruding aluminum profiles for water-cooling plates of new energy vehicles. The reverse extrusion equipment and reverse extrusion die used in Example 3 are used for extrusion, and the experimental steps and conditions are the same as those in Example 3. The difference from Example 3 is that in this example, the ingredients are: Si: ≤0.08%, Fe: ≤0.50%, Cu: 2.55%, Mn: ≤0.07%, Mg: 2.6%, Cr: 0.05% to 0.1%, Zn: 7.0%, Ti: 0.1%, Zr: 0.2%, Sc: 0.2%. The test results of the automobile bars produced in this example are as follows:

[0144] Mechanical properties test: Testing equipment: AG-X 100KN electronic universal testing machine. Test method: GB / T16865-2013 Specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products. Four pieces were randomly selected from the produced automotive bars and numbered. The results are shown in Table 25:

[0145] Table 25 Mechanical properties results

[0146]

[0147]

[0148] High-magnification tissue inspection: Test equipment: AXIO universal research-grade inverted material microscope. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy product tissue inspection method Part 1: Microstructure inspection method. One piece was randomly selected from the produced automobile bars for testing. The test results are shown in Table 26 and Fig.12 shown.

[0149] Table 26 Metallographic high magnification structure

[0150]

[0151] Macroscopic test: alkaline corrosive liquid for testing equipment. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy product structure inspection method Part 2: Macroscopic structure inspection method. Four pieces were randomly selected from the produced automobile bars and numbered. The results are shown in Table 27:

[0152] Table 27 Macroscopic tissue test

[0153]

[0154] Comparative Example 1: This comparative example provides a method for producing a 7-series aluminum alloy reverse extrusion automobile bar. The aluminum alloy raw material is prepared using the batching ratio in Example 3. The difference from Example 3 is that a conventional reverse extrusion die is used for extrusion. Specifically, the method comprises the following steps:

[0155] S1. Ingredients: Prepare aluminum alloy raw materials according to the following weight ratios: Si: 0.07%, Fe: 0.13%, Cu: 2.52%, Mn: 0.05%, Mg: 2.49%, Cr: 0.06%, Zn: 6.88%, Ti: 0.08%, Zr: 0.16%, Sc: 0.18%, single impurity: 0.05%, and the balance is Al;

[0156] S2. Melting and casting: Put the aluminum alloy raw material prepared in step S1 into a smelting furnace for melting and casting to obtain a cast rod. During the melting and casting, a semi-continuous casting method is used for melting and casting. Foam ceramics are used for filtration during the melting and casting process, and Al-Ti-B wire is used for grain refinement. The melting temperature is 690℃-750℃, the refining temperature is 720℃-740℃, the refining agent dosage is 2.8kg / TAl, the waste addition amount is ≤10%, and the hydrogen element is 0.15ml / 100g. The slag content of the ingot meets the secondary requirements in GB / T32186-2015;

[0157] S3. Homogenization of cast rods: The cast rods obtained in step S2 were subjected to a primary homogenization system and a secondary homogenization system to obtain round ingots. The primary homogenization annealing system was 310 ° C and the holding time was 6.5 hours; the secondary homogenization annealing system was 470 ° C and the holding time was 22 hours;

[0158] S4. Extrusion: The round ingot in step S3 is placed in a reverse extrusion device for extrusion to obtain a rod, wherein the extrusion die is a conventional rod extrusion flat die without a tapered portion, the round ingot is heated by a stepwise heating method, and a Φ81 mm rod is produced by a 20MN reverse aluminum extruder. The round ingot is a Φ247 mm round ingot, the heating temperature of the head end of the round ingot is 405°C, the heating temperature of the tail end is 385°C, the heating temperature of the rod extrusion flat die is 440°C, and the temperature of the extrusion barrel is 403°C.

[0159] In this embodiment, the profile extruded by the rod extrusion flat die has severe peeling on the surface and cannot be extruded continuously.

[0160] Comparative Example 2: This comparative example provides a method for producing a 7-series aluminum alloy reverse extrusion automobile bar, which uses the extrusion equipment and reverse extrusion die used in Example 3 for extrusion. Unlike Example 3, this comparative example only uses one homogenization, and specifically includes the following steps:

[0161] S1. Ingredients: Prepare aluminum alloy raw materials according to the following weight ratios: Si: 0.07%, Fe: 0.13%, Cu: 2.52%, Mn: 0.05%, Mg: 2.49%, Cr: 0.06%, Zn: 6.88%, Ti: 0.08%, Zr: 0.16%, Sc: 0.18%, single impurity: 0.05%, and the balance is Al;

[0162] S2. Melting and casting: Put the aluminum alloy raw material prepared in step S1 into a smelting furnace for melting and casting to obtain a cast rod. During the melting and casting, a semi-continuous casting method is used for melting and casting. Foam ceramics are used for filtration during the melting and casting process, and Al-Ti-B wire is used for grain refinement. The melting temperature is 690℃-750℃, the refining temperature is 720℃-740℃, the refining agent dosage is 2.8kg / TAl, the waste addition amount is ≤10%, and the hydrogen element is 0.15ml / 100g. The slag content of the ingot meets the secondary requirements in GB / T32186-2015;

[0163] S3. Cast rod homogenization: The cast rod obtained in step S2 was homogenized. Unlike Example 3, this comparative example only used one homogenization, the homogenization temperature was 470°C, and the holding time was 22h;

[0164] S4. Extrusion: placing the round ingot in step S3 into a reverse extrusion device for extrusion to obtain a rod, the reverse extrusion die comprises a first tapered area 1-1, a cylindrical area 1-2, a second tapered area 1-3 and a working zone 2 connected in sequence, the angle between the side wall of the first tapered area 1-1 and the axis is 69.3°, the angle between the side wall of the second tapered area 1-3 and the axis is 58.5°, the round ingot is heated by a stepwise heating method, and a Φ81mm rod is produced by a 20MN reverse aluminum extruder, the round ingot is selected as a Φ247mm round ingot, the heating temperature of the head end of the round ingot is 405°C, the heating temperature of the tail end is 385°C, the heating temperature of the reverse extrusion die is 440°C, and the temperature of the extrusion barrel is 403°C;

[0165] S5. Quenching, stretching and cutting of bars: quenching the bars obtained in step S4, wherein the cooling method in the quenching is water cooling, the quenching temperature is 443°C, and the temperature out of the quenching zone is ≤50°C. The quenched bars are stretched and straightened, and the stretching rate is 0.5%-1%. The stretched and straightened bars are cut into a specified length;

[0166] S6. Aging treatment: The rod cut in step S5 is subjected to aging treatment at an aging temperature of 160° C. for 14 h to obtain an automobile rod.

[0167] Mechanical properties test: Testing equipment: AG-X 100KN electronic universal testing machine. Test method: GB / T16865-2013 Specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products. Four pieces were randomly selected from the produced automotive bars and numbered. The results are shown in Table 28:

[0168] Table 28 Mechanical properties results

[0169]

[0170] High-magnification tissue inspection: Test equipment: AXIO universal research-grade inverted material microscope. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy product tissue inspection method Part 1: Microstructure inspection method. One piece was randomly selected from the produced automobile bars for testing. The test results are shown in Table 29 and Fig.13 shown.

[0171] Table 29 High magnification microstructure

[0172]

[0173] Macroscopic test: alkaline corrosive liquid for testing equipment. Test standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extrusion profiles. Test method: GB / T3246.2-2012 Deformed aluminum and aluminum alloy product structure inspection method Part 2: Macroscopic structure inspection method. Four pieces were randomly selected from the produced automobile bars and numbered. The results are shown in Table 30:

[0174] Table 30 Macroscopic tissue test

[0175]

[0176] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A method for producing 7 series aluminum alloy reverse extrusion automobile bars, characterized in that: The steps include: S1. Ingredients: Prepare aluminum alloy raw materials according to the following weight ratios: Si: ≤0.08%, Fe: ≤0.50%, Cu: 2.5%~2.55%, Mn: ≤0.07%, Mg: 2.4%~2.6%, Cr: 0.05%~0.1%, Zn: 6.8%~7.0%, Ti: 0.07%~0.1%, Zr: 0.15%~0.2%, Sc: 0.17%~0.2%, single impurity ≤0.05%, total impurity ≤0.15%, and the balance is Al; S2. Casting: The aluminum alloy raw material prepared in step S1 is placed in a smelting furnace for casting to obtain a cast rod; S3. Homogenization of cast rods: subjecting the cast rods obtained in step S2 to a primary homogenization system and a secondary homogenization system to obtain round ingots, wherein the temperature of the primary homogenization annealing system is 305-315°C, and the holding time is 4-8 hours; the temperature of the secondary homogenization annealing system is 460-470°C, and the holding time is 20-23 hours; S4. Extrusion: placing the round ingot in step S3 into a reverse extrusion device for extrusion to obtain a rod, wherein the reverse extrusion die comprises a rear chamber (1) and a working belt (2) connected in sequence, the rear chamber (1) comprises a first conical zone (1-1), a cylindrical zone (1-2) and a second conical zone (1-3) connected in sequence, the inlet diameter of the first conical zone (1-1) is larger than the outlet diameter, the outlet diameter of the first conical zone (1-1) is equal to the diameter of the cylindrical zone (1-2), the inlet diameter of the second conical zone (1-3) is equal to the diameter of the cylindrical zone (1-2), and the outlet diameter of the second conical zone (1-3) is equal to the outlet diameter of the cylindrical zone (1-2). ), the inlet diameter of the second tapered zone (1-3) is larger than the outlet diameter, the second tapered zone (1-3) is connected to the working belt (2), the outlet diameter of the second tapered zone (1-3) is equal to the diameter of the working belt (2), the round ingot is heated by a step-by-step heating method, the heating temperature of the head end of the round ingot is 390-410°C, the heating temperature of the tail end is 370-390°C, the temperature of the extrusion barrel is 390-420°C, the heating temperature of the reverse extrusion die is 400-450°C, and the product speed is 3.5m / min-4m / min; S5. Quenching, stretching and cutting of the rod: quenching the rod obtained in step S4 to obtain a quenched rod, stretching and straightening the quenched rod and cutting it into a specified length; S6. Aging treatment: The rod cut in step S5 is subjected to aging treatment at an aging temperature of 157 to 163° C. for 14 h to obtain an automobile rod.

2. The method for producing a 7 series aluminum alloy reverse extrusion automobile bar according to claim 1, characterized in that: In the step S1, the ingredients are Si: ≤0.05%, Fe: ≤0.39%, Cu: 2.52%~2.54%, Mn: ≤0.05%, Mg: 2.53%~2.58%, Cr: 0.07%~0.09%, Zn: 6.88%~6.95%, Ti: 0.08%~0.09%, Zr: 0.17%~0.19%, Sc: 0.17%~0.18%, single impurity ≤0.05%, total impurity ≤0.15%, and the balance is Al.

3. The method for producing a 7 series aluminum alloy reverse extrusion automobile bar according to claim 1, characterized in that: In the step S2, during the melting and casting, a semi-continuous casting method is adopted, foam ceramics are used for filtration during the melting and casting process, Al-Ti-B wire is used for grain refinement, the melting temperature is 690°C-750°C, the refining temperature is 720°C-740°C, the refining agent dosage is 2.8kg / TAl, the waste addition amount is ≤10%, and the hydrogen element is 0.15ml / 100g.

4. The method for producing a 7 series aluminum alloy reverse extrusion automobile bar according to claim 1, characterized in that: In step S3, the temperature of the primary homogenization annealing system is 310° C., and the holding time is 6.5 hours; the temperature of the secondary homogenization annealing system is 470° C., and the holding time is 22 hours.

5. The method for producing a 7 series aluminum alloy reverse extrusion automobile bar according to claim 1, characterized in that: In the step S3, the round ingot is a Φ247 mm round ingot.

6. The method for producing a 7 series aluminum alloy reverse extrusion automobile bar according to claim 1, characterized in that: In the step S4, the angle between the side wall of the first tapered area (1-1) and the axis is 68° to 71°, and the angle between the side wall of the second tapered area (1-3) and the axis is 56.5° to 60°.

7. The method for producing 7 series aluminum alloy reverse extrusion automobile bars according to claim 1, characterized in that: In step S4, the distance from the entrance to the exit of the first conical zone (1-1) is 25 mm; the distance from the entrance to the exit of the cylindrical zone (1-2) is 25 mm; and the distance from the entrance to the exit of the second conical zone (1-3) is 15 mm.

8. The method for producing 7 series aluminum alloy reverse extrusion automobile bars according to claim 1, characterized in that: In the step S5, the cooling method in the quenching is water cooling, the temperature of the quenching zone is 420-450°C, and the temperature out of the quenching zone is ≤50°C.

9. The method for producing 7 series aluminum alloy reverse extrusion automobile bars according to claim 1, characterized in that: In step S5, the diameter of the cylindrical area (1-2) is 81 mm.

10. The method for producing 7 series aluminum alloy reverse extrusion automobile bars according to claim 1, characterized in that: In the step S5, the stretching rate in the stretching and straightening process is 0.5%-1%.

Images