Aluminum alloy machining method through accumulative ply rolling, contact heating and artificial aging

Abstract

The invention relates to the technical field of material processing, and particularly discloses an aluminum alloy processing method through accumulative ply rolling, contact heating and artificial aging. The processing technology comprises the following steps: (1) carrying out homogenization treatment on an aluminum alloy material; (2) cleaning the surface of the aluminum alloy material; (3) pre-deformation is applied to the aluminum alloy material by adopting an accumulative ply rolling method, and water quenching treatment is performed after ply rolling is completed; (4) an upper die and a lower die of a contact heating device are preheated to the solid solution temperature of the aluminum alloy material, and the aluminum alloy material is placed between the upper die and the lower die for contact heating to achieve solid solution treatment; (5) stamping, forming and quenching treatment; and (6) the stamped and quenched aluminum alloy material is transferred into a heating furnace to be subjected to artificial aging treatment. By means of the aluminum alloy machining method of accumulative ply rolling, contact heating and artificial aging, the solid solution time and aging time of the aluminum alloy can be greatly shortened, the strength and hardness of the aluminum alloy are improved, and the ductility of the aluminum alloy is not lost.

Description

Technical Field

[0001] The invention relates to the technical field of material processing, and specifically discloses an aluminum alloy processing method through cumulative rolling, contact heating and artificial aging. Background Art

[0002] In recent years, with the increasing global requirements for environmental protection and energy efficiency, automobile lightweighting has become an important trend in the development of the industry. According to statistics, if the weight of the whole vehicle is reduced by 10%, the fuel efficiency can be improved by 6%-8%; for every 100 kg reduction in the curb weight of the vehicle, the fuel consumption per 100 kilometers can be reduced by 0.3-0.6 liters; if the weight of the vehicle is reduced by 1%, the fuel consumption can be reduced by 0.7%. Therefore, automobile lightweighting has become an effective measure to reduce automobile emissions and improve combustion efficiency, and it is also the main direction of automobile material development. There are three main ways to achieve automobile lightweighting, namely, the use of lightweight and high-strength materials, optimized structural design and advanced manufacturing processes. At present, automobile lightweight materials mainly include high-strength steel, aluminum alloy, magnesium alloy, carbon fiber composite materials, etc. Aluminum alloy has high strength and good crash resistance. It can absorb more energy during a collision, thereby improving the safety performance of the vehicle. Compared with steel materials, the density of aluminum alloy is only one-third of the former. The use of aluminum alloy materials can significantly reduce the overall mass of the car. This will help reduce fuel consumption and reduce CO2 emissions, thereby achieving environmental protection goals.

[0003] Aluminum alloys are increasingly used in the automotive industry due to their excellent performance characteristics, and their proportion in the body structure is gradually increasing. Among them, high-strength aluminum alloys represented by 7000 series aluminum alloys have higher strength, which can make the applied plates thinner and further reduce weight, and they have the potential to be used as high-load structural parts of the body. However, high-strength aluminum alloys face many challenges in the application process. Due to poor plasticity, the forming process at room temperature is particularly difficult. Traditional cold stamping technology can only form aluminum alloy parts with simple shapes and small deformation, while parts with complex shapes can only be formed by stamping them separately and then connecting them, resulting in reduced production efficiency and increased costs. In addition, formed parts often show failure phenomena such as rebound, cracking, and wrinkling. Studies have shown that increasing the forming temperature can significantly improve the forming performance of aluminum alloys, and the heat treatment-stamping integrated technology formed by integrating heat treatment into stamping has become an important development direction.

[0004] According to research, the existing heat treatment-stamping integrated technology requires first heating the heating furnace to the solid solution temperature, then putting the aluminum alloy sheet into the furnace for a period of time to ensure that the material is fully solid-solutionized, and then using a robotic arm to quickly transfer the sheet to the mold in a very short time (about 7 seconds) to achieve rapid quenching and stamping forming, forming a supersaturated solid solution, and finally, the parts after forming and quenching are artificially aged to precipitate second-phase particles, thereby achieving the purpose of aging strengthening. However, the heat treatment stage involved in the existing hot stamping process is time-consuming. Due to the slow heating rate of the heating furnace, the heating and solid solution treatment time usually takes 10min-40min. The aging treatment usually needs to be kept in the heating furnace for at least 24h to reach the peak aging. The time required for the solid solution treatment method in the heating furnace is difficult to coordinate with the stamping rhythm, resulting in the inability to meet the efficiency requirements of the actual production line. Long-term heat treatment not only increases production costs, but also leads to increased energy consumption, posing challenges to both economic benefits and environmental protection.

[0005] According to the search of Chinese invention patent CN112547798A, a method for preparing high-strength heterogeneous high-entropy alloys by cumulative rolling is introduced. The principle is that a layered heterogeneous high-entropy alloy with high strength and toughness can be obtained by cumulative rolling + annealing treatment, but the annealing time of this process is relatively long, usually requiring 60min-90min, and this preparation method is suitable for high-entropy alloys but not for aluminum alloy materials.

[0006] Chinese invention patent CN112845587A introduces a method for preparing gradient structure metal materials by incremental cumulative rolling. The principle is to increase the gradient of the refinement degree of the material microstructure from the surface to the core by 3-5 times of incremental-cumulative rolling, so that the material has both high strength and good toughness. However, this process is only for obtaining structural materials with gradient distribution of microstructure, and cannot solve the problem that the traditional heat treatment-stamping process takes a long time to heat treat and cannot meet the efficiency requirements of the actual production line.

[0007] Chinese invention patent CN115365361A discloses a 7075-T6 aluminum alloy contact heating forming method, the principle of which is to use a contact heating device to quickly heat the 7075T6 aluminum alloy sheet to about 400°C, so that it can obtain good plasticity for further forming. However, this process does not leave enough solid solution treatment time after the aluminum alloy is contact heated, but directly performs stamping, and the mechanical properties can only reach more than 75% of the strength of the T6 aluminum alloy. The aluminum alloy material after contact heating-stamping needs to be naturally aged at room temperature for more than 2 days. The aging period is long and the strength can only reach more than 90% of the T6 state.

[0008] Therefore, the present invention aims to provide an aluminum alloy processing method that improves production efficiency, reduces production costs and energy consumption Summary of the invention

[0009] To this end, the technical problem to be solved by the present invention is to shorten the solution treatment time and aging time of the aluminum alloy material in the heat treatment-stamping integration process, improve the efficiency of the hot stamping process, and reduce production costs and energy consumption.

[0010] In order to solve the above technical problems, the present invention provides an aluminum alloy processing method through cumulative rolling, contact heating and artificial aging. The aluminum alloy material is pre-deformed by the cumulative rolling method, and the plate is directly heated by using a contact heating device and upper and lower flat molds pre-heated to a specific temperature. The aluminum alloy is solution treated by heat conduction to achieve heating to a temperature close to the solution temperature within 15s to 20s, and the solution treatment is completed within 25s to 35s. The time to reach the aging peak in the artificial aging process is shortened to 18h to 20h, and the strength and hardness of the aluminum alloy are improved without losing elongation.

[0011] The present invention discloses an aluminum alloy processing method through cumulative rolling, contact heating and artificial aging, which adopts the following technical scheme:

[0012] The aluminum alloy processing method by cumulative rolling, contact heating and artificial aging comprises the following steps:

[0013] (1) Homogenizing the aluminum alloy material;

[0014] (2) Clean the surface of the aluminum alloy material and remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0015] (3) applying pre-deformation to the aluminum alloy material by cumulative rolling, the cumulative rolling times of the aluminum alloy material are 0 to 5 times, the reduction of a single rolling pass is 20% to 60%, and water quenching is performed after the rolling is completed;

[0016] (4) preheating the upper and lower molds of the contact heating device to the solution temperature of the aluminum alloy material, and placing the aluminum alloy material between the upper and lower molds for contact heating to achieve solution treatment;

[0017] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment;

[0018] (6) The aluminum alloy material after stamping and quenching is transferred to a heating furnace for artificial aging treatment.

[0019] Preferably, in step (6), the artificial aging temperature of the aluminum alloy material is 100° C. to 200° C., and the aging time is 12 h to 24 h.

[0020] Preferably, in step (3), the cumulative number of times of rolling of the aluminum alloy material is 2, and the reduction amount of a single rolling pass is 50%.

[0021] Preferably, in step (4), the solution temperature range of the aluminum alloy material is 450°C to 550°C, and the solution time is 25s to 35s.

[0022] Preferably, in step (5), the mold closing and holding time of the stamping process is 25s to 35s, and the holding pressure is 80KN to 120KN.

[0023] Preferably, in step (3), the rolling temperature of the aluminum alloy material is 200°C to 350°C.

[0024] Preferably, in step (1), the homogenization temperature of the aluminum alloy material is 450° C. to 550° C., and the holding time is 1 h to 12 h.

[0025] Preferably, in step (1), the thickness of the aluminum alloy material is 1.5 mm to 2.5 mm.

[0026] Preferably, in step (2), the surface of the aluminum alloy material is cleaned using acetone and a copper wire brush.

[0027] Preferably, in step (3), during the multiple rolling passes, the material obtained by the previous rolling pass needs to be cut into the same size in the middle, and the same process steps are repeated, and step (2) needs to be performed before each rolling pass.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] The present invention applies pre-deformation to the aluminum alloy material by the method of cumulative rolling, adopts a contact heating device, utilizes upper and lower flat plate molds preheated to a specific temperature to directly heat the sheet material, and performs solid solution treatment on the aluminum alloy by a heat conduction method, thereby quickly completing the solid solution treatment and improving production efficiency. At the same time, the strength and hardness of the aluminum alloy are improved without losing elongation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the cumulative rolling step of the present invention;

[0031] Figure 2 The peak aging time is compared between the contact heating process of the present invention and the solution treatment process of a heating furnace in the prior art. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. It should be understood that the specific embodiments are only used to explain the present invention, but the embodiments are not intended to limit the present invention.

[0033] In the present invention, unless otherwise explained, technical and scientific terms used in the present invention have the same meanings as commonly understood by those skilled in the art to which the present invention belongs.

[0034] In the present invention, unless otherwise stated, when the terms "comprise" and / or "include" are used in the specification of the present invention, it indicates the existence of the described features, integers, steps, operations, but does not exclude the existence or addition of one or more other features, integers, steps, operations or their combinations.

[0035] In the present invention, unless otherwise stated, the ranges and alternatives of the parameters of the heat treatment process can be combined with each other to form a new heat treatment process.

[0036] In the present invention, unless otherwise specified, if no specific conditions are specified in the examples, the experiments were carried out according to conventional conditions or conditions recommended by the manufacturer.

[0037] In the present invention, unless otherwise specified, all reagents or instruments used without indicating the manufacturer are conventional products that can be purchased from the market.

[0038] Example 1

[0039] An aluminum alloy processing process of cumulative rolling, contact heating and artificial aging specifically comprises the following steps:

[0040] (1) A 2 mm thick 7075-T6 aluminum alloy was selected as the raw material and homogenized at 480 °C for 3 h;

[0041] (2) Use acetone and a copper wire brush to clean the surface of the aluminum alloy material to remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0042] (3) Pre-deformation is applied to the aluminum alloy material by cumulative rolling, the rolling temperature is 250° C., the reduction of a single rolling pass is 50%, the number of rolling is 0, and water quenching is performed after the rolling is completed;

[0043] (4) preheating the upper and lower molds of the contact heating device to 480°C, placing the aluminum alloy material between the upper and lower molds for contact heating and solution treatment, the solution temperature is 480°C, and the solution time is 30s;

[0044] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment. The holding time is 30 seconds and the holding pressure is 100KN;

[0045] (6) The plate after solution quenching is transferred to a heating furnace and artificially aged at 120 °C for 12 h.

[0046] Example 2

[0047] An aluminum alloy processing process of cumulative rolling-contact heating-artificial aging specifically comprises the following steps:

[0048] (1) A 2 mm thick 7075-T6 aluminum alloy was selected as the raw material and homogenized at 480 °C for 3 h;

[0049] (2) Use acetone and a copper wire brush to clean the surface of the aluminum alloy material to remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0050] (3) Pre-deformation is applied to the aluminum alloy material by cumulative rolling, the rolling temperature is 250° C., the reduction of a single rolling pass is 50%, the number of rolling is 0, and water quenching is performed after the rolling is completed;

[0051] (4) preheating the upper and lower molds of the contact heating device to 480°C, placing the aluminum alloy material between the upper and lower molds for contact heating and solution treatment, the solution temperature is 480°C, and the solution time is 30s;

[0052] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment. The holding time is 30 seconds and the holding pressure is 100KN;

[0053] (6) The plate after solution quenching is transferred to a heating furnace and artificially aged at 120°C for 18 hours.

[0054] Example 3

[0055] An aluminum alloy processing process of cumulative rolling-contact heating-artificial aging specifically comprises the following steps:

[0056] (1) A 2 mm thick 7075-T6 aluminum alloy was selected as the raw material and homogenized at 480 °C for 3 h;

[0057] (2) Use acetone and a copper wire brush to clean the surface of the aluminum alloy material to remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0058] (3) Pre-deformation is applied to the aluminum alloy material by cumulative rolling, the rolling temperature is 250° C., the reduction of a single rolling pass is 50%, the number of rolling is 0, and water quenching is performed after the rolling is completed;

[0059] (4) preheating the upper and lower molds of the contact heating device to 480°C, placing the aluminum alloy material between the upper and lower molds for contact heating and solution treatment, the solution temperature is 480°C, and the solution time is 30s;

[0060] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment. The holding time is 30 seconds and the holding pressure is 100KN;

[0061] (6) The plate after solution quenching is transferred to a heating furnace and artificially aged at 120 °C for 20 h.

[0062] Example 4

[0063] An aluminum alloy processing process of cumulative rolling-contact heating-artificial aging specifically comprises the following steps:

[0064] (1) A 2 mm thick 7075-T6 aluminum alloy was selected as the raw material and homogenized at 480 °C for 3 h;

[0065] (2) Use acetone and a copper wire brush to clean the surface of the aluminum alloy material to remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0066] (3) Pre-deformation is applied to the aluminum alloy material by cumulative rolling, the rolling temperature is 250° C., the reduction of a single rolling pass is 50%, the number of rolling is 0, and water quenching is performed after the rolling is completed;

[0067] (4) preheating the upper and lower molds of the contact heating device to 480°C, placing the aluminum alloy material between the upper and lower molds for contact heating and solution treatment, the solution temperature is 480°C, and the solution time is 30s;

[0068] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment. The holding time is 30 seconds and the holding pressure is 100KN;

[0069] (6) The plate after solution quenching is transferred to a heating furnace and artificially aged at 120 °C for 24 h.

[0070] Example 5

[0071] An aluminum alloy processing process of cumulative rolling-contact heating-artificial aging specifically comprises the following steps:

[0072] (1) A 2 mm thick 7075-T6 aluminum alloy was selected as the raw material and homogenized at 480 °C for 3 h;

[0073] (2) Use acetone and a copper wire brush to clean the surface of the aluminum alloy material to remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0074] (3) Pre-deformation is applied to the aluminum alloy material by cumulative rolling, the rolling temperature is 250° C., the reduction of a single rolling pass is 50%, the number of rolling is 1, and water quenching is performed after the rolling is completed;

[0075] (4) preheating the upper and lower molds of the contact heating device to 480°C, placing the aluminum alloy material between the upper and lower molds for contact heating and solution treatment, the solution temperature is 480°C, and the solution time is 30s;

[0076] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment. The holding time is 30 seconds and the holding pressure is 100KN;

[0077] (6) The plate after solution quenching is transferred to a heating furnace and artificially aged at 120 °C for 18 h.

[0078] Example 6

[0079] An aluminum alloy processing process of cumulative rolling-contact heating-artificial aging specifically comprises the following steps:

[0080] (1) A 2 mm thick 7075-T6 aluminum alloy was selected as the raw material and homogenized at 480 °C for 3 h;

[0081] (2) Use acetone and a copper wire brush to clean the surface of the aluminum alloy material to remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0082] (3) Pre-deformation is applied to the aluminum alloy material by cumulative rolling, the rolling temperature is 250° C., the reduction of a single rolling pass is 50%, the number of rolling is 1, and water quenching is performed after the rolling is completed;

[0083] (4) preheating the upper and lower molds of the contact heating device to 480°C, placing the aluminum alloy material between the upper and lower molds for contact heating and solution treatment, the solution temperature is 480°C, and the solution time is 30s;

[0084] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment. The holding time is 30 seconds and the holding pressure is 100KN;

[0085] (6) The plate after solution quenching is transferred to a heating furnace and artificially aged at 120 °C for 20 h.

[0086] Example 7

[0087] An aluminum alloy processing process of cumulative rolling-contact heating-artificial aging specifically comprises the following steps:

[0088] (1) A 2 mm thick 7075-T6 aluminum alloy was selected as the raw material and homogenized at 480 °C for 3 h;

[0089] (2) Use acetone and a copper wire brush to clean the surface of the aluminum alloy material to remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0090] (3) Pre-deformation is applied to the aluminum alloy material by cumulative rolling, the rolling temperature is 250° C., the reduction of a single rolling pass is 50%, the number of rolling is 1, and water quenching is performed after the rolling is completed;

[0091] (4) preheating the upper and lower molds of the contact heating device to 480°C, placing the aluminum alloy material between the upper and lower molds for contact heating and solution treatment, the solution temperature is 480°C, and the solution time is 30s;

[0092] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment. The holding time is 30 seconds and the holding pressure is 100KN;

[0093] (6) The plate after solution quenching is transferred to a heating furnace and artificially aged at 120 °C for 24 h.

[0094] Example 8

[0095] An aluminum alloy processing process of cumulative rolling-contact heating-artificial aging specifically comprises the following steps:

[0096] (1) A 2 mm thick 7075-T6 aluminum alloy was selected as the raw material and homogenized at 480 °C for 3 h;

[0097] (2) Use acetone and a copper wire brush to clean the surface of the aluminum alloy material to remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0098] (3) Pre-deformation is applied to the aluminum alloy material by cumulative rolling, the rolling temperature is 250°C, the reduction of a single rolling pass is 50%, the number of rolling is 2 times, and water quenching is performed after the rolling is completed;

[0099] (4) preheating the upper and lower molds of the contact heating device to 480°C, placing the aluminum alloy material between the upper and lower molds for contact heating and solution treatment, the solution temperature is 480°C, and the solution time is 30s;

[0100] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment. The holding time is 30 seconds and the holding pressure is 100KN;

[0101] (6) The plate after solution quenching is transferred to a heating furnace and artificially aged at 120°C for 16 hours.

[0102] Example 9

[0103] An aluminum alloy processing process of cumulative rolling-contact heating-artificial aging specifically comprises the following steps:

[0104] (1) A 2 mm thick 7075-T6 aluminum alloy was selected as the raw material and homogenized at 480 °C for 3 h;

[0105] (2) Use acetone and a copper wire brush to clean the surface of the aluminum alloy material to remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0106] (3) Pre-deformation is applied to the aluminum alloy material by cumulative rolling, the rolling temperature is 250°C, the reduction of a single rolling pass is 50%, the number of rolling is 2 times, and water quenching is performed after the rolling is completed;

[0107] (4) preheating the upper and lower molds of the contact heating device to 480°C, placing the aluminum alloy material between the upper and lower molds for contact heating and solution treatment, the solution temperature is 480°C, and the solution time is 30s;

[0108] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment. The holding time is 30 seconds and the holding pressure is 100KN;

[0109] (6) The plate after solution quenching is transferred to a heating furnace and artificially aged at 120 °C for 18 h.

[0110] Example 10

[0111] An aluminum alloy processing process of cumulative rolling-contact heating-artificial aging specifically comprises the following steps:

[0112] (1) A 2 mm thick 7075-T6 aluminum alloy was selected as the raw material and homogenized at 480 °C for 3 h;

[0113] (2) Use acetone and a copper wire brush to clean the surface of the aluminum alloy material to remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0114] (3) Pre-deformation is applied to the aluminum alloy material by cumulative rolling, the rolling temperature is 250°C, the reduction of a single rolling pass is 50%, the number of rolling is 2 times, and water quenching is performed after the rolling is completed;

[0115] (4) preheating the upper and lower molds of the contact heating device to 480°C, placing the aluminum alloy material between the upper and lower molds for contact heating and solution treatment, the solution temperature is 480°C, and the solution time is 30s;

[0116] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment. The holding time is 30 seconds and the holding pressure is 100KN;

[0117] (6) The plate after solution quenching is transferred to a heating furnace and artificially aged at 120 °C for 20 h.

[0118] Comparative Example 1

[0119] An aluminum alloy processing process of cumulative rolling-contact heating-artificial aging specifically comprises the following steps:

[0120] (1) A 2 mm thick 7075-T6 aluminum alloy was selected as the raw material and homogenized at 480 °C for 3 h;

[0121] (2) Use acetone and a copper wire brush to clean the surface of the aluminum alloy material to remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0122] (3) Pre-deformation is applied to the aluminum alloy material by cumulative rolling, the rolling temperature is 250° C., the reduction of a single rolling pass is 50%, the number of rolling is 1, and water quenching is performed after the rolling is completed;

[0123] (4) preheating the upper and lower molds of the contact heating device to 480°C, placing the aluminum alloy material between the upper and lower molds for contact heating and solution treatment, the solution temperature is 480°C, and the solution time is 30s;

[0124] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment. The holding time is 30 seconds and the holding pressure is 100KN;

[0125] (6) The plate after solution quenching is transferred to a heating furnace and artificially aged at 120 °C for 10 h.

[0126] Comparative Example 2

[0127] An aluminum alloy processing process of cumulative rolling-contact heating-artificial aging specifically comprises the following steps:

[0128] (1) A 2 mm thick 7075-T6 aluminum alloy was selected as the raw material and homogenized at 480 °C for 3 h;

[0129] (2) Use acetone and a copper wire brush to clean the surface of the aluminum alloy material to remove the oxide layer and oil stains on the surface until the surface is clean and smooth;

[0130] (3) Pre-deformation is applied to the aluminum alloy material by cumulative rolling, the rolling temperature is 250° C., the reduction of a single rolling pass is 50%, the number of rolling is 1, and water quenching is performed after the rolling is completed;

[0131] (4) preheating the upper and lower molds of the contact heating device to 480°C, placing the aluminum alloy material between the upper and lower molds for contact heating and solution treatment, the solution temperature is 480°C, and the solution time is 30s;

[0132] (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment. The holding time is 30 seconds and the holding pressure is 100KN;

[0133] (6) The plate after solution quenching is transferred to a heating furnace and artificially aged at 120 °C for 26 h.

[0134] The mechanical properties of the above cases were tested, and the results are shown in Table 1.

[0135] Table 1 Mechanical properties test of each embodiment and comparative example

[0136]

[0137]

[0138] The aluminum alloy material undergoes large deformation after cumulative roll-bonding quenching, and there is a certain amount of deformation energy storage. The rolling temperature, feed speed and pressing amount during the roll-bonding process need to be strictly controlled to reduce bending deformation. The material needs to be straightened, polished and trimmed before contact heating, which is not conducive to production efficiency. In this regard, the key points of the present invention are:

[0139] 1) After the contact heating solution treatment and aging treatment, the process of the present invention releases deformation energy, so that the pre-deformed alloy completes recrystallization, the grains are significantly refined, and the material strength is effectively improved. At the same time, the rolling process introduces high-density dislocations, which accelerates the rate of aging precipitation, thereby shortening the peak aging time.

[0140] 2) Contact heating has a fast heating rate, and the second phase in the aluminum alloy matrix is ​​quickly dissolved, which increases the supersaturation of the solid solution. In the subsequent artificial aging process, the precipitated phase is more numerous, more evenly distributed, and smaller in size. Therefore, the performance of the contact heated sample after aging treatment is better than that of the T6 state sample.

[0141] 3) The artificial aging treatment at 100°C to 200°C is used. Compared with the existing process of natural aging at room temperature, the precipitation process of the strengthening phase is slower, so the aging period is longer. The present invention uses a heating furnace at 120°C for artificial aging, which can accelerate the precipitation of the strengthening phase and shorten the aging period.

[0142] As can be seen from Examples 1-4 in Table 1, the contact heating method used in this article can be used to process aluminum alloy materials. In addition to greatly shortening the time required for heating and solid solution of aluminum alloys, only 12 hours of artificial aging process is required later, and the yield strength and tensile strength of aluminum alloy materials can exceed the original T6 state aluminum alloy strength, and the time for the artificial aging process to reach peak aging can be shortened from 24 hours required by the traditional process to 20 hours; it can be seen from Examples 5-7 that after the introduction of the rolling process before contact heating, the hardness, yield strength and tensile strength of the aluminum alloy are improved after the same artificial aging time, and its elongation is not lost; it can be seen from Examples 8-10 that when the cumulative rolling times are increased to 2 times, the time for the artificial aging process to reach peak aging can be further shortened to 18 hours. This is because the aluminum alloy has a precipitation strengthening effect during the aging process, and the fine precipitation phase is evenly distributed in the aluminum alloy matrix, which increases the strength and hardness of the aluminum alloy. As the aging time increases, the number of precipitation phases increases, and the strengthening effect increases until the peak aging time is reached. In addition, if the aging time is further extended, as shown in Comparative Examples 1-2, the aluminum alloy exhibits an over-aging phenomenon, the precipitated phase undergoes a phase transformation, the size of the phase coarsens, and the strengthening effect is significantly weakened, so the strength and hardness decrease. Therefore, in the method of the present invention, the artificial aging time is strictly controlled to be 12 to 24 hours.

[0143] See Figure 2 In the existing solution treatment method of a heating furnace, the heating furnace has a slow heating rate, and the heating and solution treatment time usually takes 10 minutes to 40 minutes. The aging treatment usually needs to be kept in the heating furnace for at least 24 hours to reach the peak aging. However, the contact heating method of the present invention can complete the heating to a temperature close to the solution temperature in 15 seconds to 20 seconds, and the solution treatment can be completed within 25 seconds to 35 seconds. The time for the aluminum alloy material to reach the peak aging through artificial aging after cumulative rolling-contact heating can be shortened to 18 hours to 20 hours.

[0144] In addition, the study also found that as the number of aluminum alloy lamination passes increases, the strength and hardness of the aluminum alloy will also increase, see Examples 11-13, this is due to the grain refinement and deformation strengthening of the material, but increasing the number of lamination passes will also increase the growth rate of the grains and the tendency of dislocation accumulation. When the number of passes increases to a certain extent, the strength and hardness of the aluminum alloy will no longer increase, and may even show a downward trend. Although increasing the number of lamination passes can improve the strength and hardness of the aluminum alloy, it will also increase the inclusion of oxides on the surface of the alloy, see Comparative Example 3, the degree of bending of the aluminum alloy increases, and cracking is prone to occur, which is not conducive to the subsequent contact heating. Therefore, the lamination process needs to be strictly controlled, and the number of lamination passes should not be too many.

[0145] The technical solution provided by the present invention is introduced in detail above. Specific examples are used in this article to illustrate the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for processing aluminum alloy by cumulative rolling, contact heating and artificial aging, characterized in that: The following steps are included: (1) Homogenizing the aluminum alloy material; (2) Clean the surface of the aluminum alloy material and remove the oxide layer and oil stains on the surface until the surface is clean and smooth; (3) applying pre-deformation to the aluminum alloy material by cumulative rolling, the cumulative rolling times of the aluminum alloy material are 0 to 5 times, the reduction of a single rolling pass is 20% to 60%, and water quenching is performed after the rolling is completed; (4) preheating the upper and lower molds of the contact heating device to the solution temperature of the aluminum alloy material, and placing the aluminum alloy material between the upper and lower molds for contact heating to achieve solution treatment; (5) After the solution treatment is completed, the aluminum alloy material is quickly transferred to the stamping die of the contact heating device to complete the stamping forming quenching treatment; (6) The aluminum alloy material after stamping and quenching is transferred to a heating furnace for artificial aging treatment.

2. The aluminum alloy processing method by cumulative rolling, contact heating and artificial aging according to claim 1, characterized in that: In step (6), the artificial aging temperature of the aluminum alloy material is 100° C. to 200° C., and the aging time is 12 h to 24 h.

3. The aluminum alloy processing method by cumulative rolling, contact heating and artificial aging according to claim 1, characterized in that: In step (3), the aluminum alloy material is rolled twice cumulatively, and the reduction in a single rolling pass is 50%.

4. The aluminum alloy processing method by cumulative rolling, contact heating and artificial aging according to claim 1, characterized in that: In step (4), the solution temperature range of the aluminum alloy material is 450°C to 550°C, and the solution time is 25s to 35s.

5. The aluminum alloy processing method by cumulative rolling, contact heating and artificial aging according to claim 1, characterized in that: In step (5), the mold holding time of the stamping process is 25s to 35s, and the holding pressure is 80KN to 120KN.

6. The aluminum alloy processing method by cumulative rolling, contact heating and artificial aging according to claim 1, characterized in that: In step (3), the rolling temperature of the aluminum alloy material is 200°C to 350°C.

7. The aluminum alloy processing method by cumulative rolling, contact heating and artificial aging according to claim 1, characterized in that: In step (1), the homogenization temperature of the aluminum alloy material is 450° C. to 550° C., and the holding time is 1 h to 12 h.

8. The aluminum alloy processing method by cumulative rolling, contact heating and artificial aging according to claim 1, characterized in that: In step (1), the thickness of the aluminum alloy material is 1.5 mm to 2.5 mm.

9. The aluminum alloy processing method by cumulative rolling, contact heating and artificial aging according to claim 1, characterized in that: In step (2), the surface of the aluminum alloy material is cleaned using acetone and a copper wire brush.

10. The aluminum alloy processing method by cumulative rolling, contact heating and artificial aging according to claim 1, characterized in that: In step (3), during the multiple rolling passes, the material obtained by the previous rolling pass needs to be cut into the same size in the middle, and the same process steps are repeated. Step (2) needs to be performed before each rolling pass.

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