Aluminum alloy processing method by accumulative roll bonding, contact heating and artificial aging

Abstract

The application relates to the technical field of material processing, and particularly discloses an aluminum alloy processing method through cumulative pack rolling, contact heating and artificial aging. The processing technology of the application comprises the following steps: (1) homogenizing treatment is performed on aluminum alloy material; (2) the surface of the aluminum alloy material is cleaned; (3) pre-deformation is applied to the aluminum alloy material by using a cumulative pack rolling method, and water quenching treatment is performed after the pack rolling is completed; (4) the upper and lower molds 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 and lower molds to perform contact heating so as to realize solid solution treatment; (5) stamping forming quenching treatment; (6) the aluminum alloy material after the stamping quenching is transferred to a heating furnace to perform artificial aging treatment. The aluminum alloy processing method through cumulative pack rolling-contact heating-artificial aging can greatly shorten the solid solution time and aging time of the aluminum alloy, improve the strength and hardness of the aluminum alloy, and does not cause loss of the elongation rate of the aluminum alloy.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of material processing, and discloses an aluminum alloy processing method through accumulative roll bonding, contact heating and artificial aging. BACKGROUND

[0002] In recent years, with the increasing global requirements for environmental protection and energy efficiency, automobile lightening has become an important trend in the industry. According to statistics, if the overall weight of an automobile is reduced by 10%, the fuel efficiency can be improved by 6%-8%; if the overall weight of an automobile is reduced by 100 kg, the fuel consumption per 100 km can be reduced by 0.3-0.6 liters; and if the weight of an automobile is reduced by 1%, the fuel consumption can be reduced by 0.7%. Therefore, automobile lightening has become an effective measure to reduce automobile emissions and improve fuel efficiency, and is also the main direction of automobile material development. There are mainly three ways to realize automobile lightening, namely, using light and high-strength materials, optimizing structural design and advanced manufacturing processes. At present, automobile lightening materials mainly include high-strength steel, aluminum alloy, magnesium alloy, carbon fiber composite material and the like. Aluminum alloy has high strength and good crashworthiness, can absorb more energy during the collision process, and thus improves the safety performance of the vehicle. Compared with steel materials, the density of aluminum alloy is only one-third of that of steel materials, and the use of aluminum alloy materials can significantly reduce the overall weight of the automobile. This will help to reduce fuel consumption and reduce CO2 emissions, thereby achieving the goal of environmental protection.

[0003] Aluminum alloy is increasingly widely used in the automobile industry due to its excellent performance characteristics, and the proportion of aluminum alloy in the vehicle body structure is gradually increasing. High-strength aluminum alloy represented by 7000 series aluminum alloy has higher strength, which can make the applied sheet thinner and further reduce weight, and has the potential to be used as a high-load structural part of the vehicle body. However, high-strength aluminum alloy faces many challenges in the application process. Due to poor plasticity, the forming process at room temperature is particularly difficult, and traditional cold stamping technology can only form aluminum alloy parts with simple shapes and small deformation amounts, and complex-shaped parts can only be realized by connecting after separate stamping, which leads to reduced production efficiency and increased cost. In addition, the formed parts often have failure phenomena such as springback, cracking and wrinkling. Studies have shown that increasing the forming temperature can significantly improve the forming performance of aluminum alloy, and the heat treatment-stamping integrated technology formed by integrating heat treatment into stamping has become an important development direction.

[0004] According to the research, the existing heat treatment-stamping integrated technology needs to first heat the heating furnace to the solid solution temperature, then put the aluminum alloy sheet into the furnace for a period of time to ensure that the material is fully solid solution, then use a mechanical 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 formed and quenched parts are artificially aged to precipitate second phase particles, thereby achieving the purpose of aging strengthening. However, the existing hot stamping process involves a long heat treatment stage. Due to the slow heating rate of the heating furnace, the heating and solid solution treatment time usually takes 10-40 minutes, and the aging treatment usually needs to be heated in the furnace for at least 24 hours to reach the peak aging. The time required for solid solution treatment by the heating furnace is difficult to coordinate with the stamping rhythm, which cannot meet the efficiency requirements of the actual production line. Long-term heat treatment not only increases production costs, but also increases energy consumption, which poses challenges to economic benefits and environmental protection.

[0005] According to the search of Chinese invention patent CN112547798A, a method for preparing high-strength heterogeneous high-entropy alloy by cumulative pack rolling is introduced. The principle is that through the method of cumulative pack rolling + annealing treatment, a layered heterogeneous high-entropy alloy with high strength and toughness can be obtained. However, the annealing treatment time of this process is relatively long, usually 60-90 minutes, 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 pack rolling. The principle is to control the microstructure refinement degree gradient of the material from the surface to the core through 3-5 times of incremental-cumulative pack rolling, so that the material has high strength and good toughness. However, this process is only to obtain a structural material with a gradient distribution of microstructure, and cannot solve the problem of long heat treatment time in traditional heat treatment-stamping process, which 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 is to use a contact heating device to quickly heat the 7075T6 aluminum alloy sheet to about 400℃, so that it obtains good plasticity for further forming. However, this process does not leave enough solid solution treatment time after the aluminum alloy is heated by contact, but directly performs stamping forming, and the mechanical properties can only reach more than 75% of the strength of T6 aluminum alloy. The aluminum alloy material after contact heating-stamping forming needs to be naturally aged at room temperature for more than 2 days, and the aging period is long and the strength can only reach more than 90% of the T6 state.

[0008] Therefore, the present application aims to provide an aluminum alloy processing method that improves production efficiency, reduces production cost and energy consumption SUMMARY

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

[0010] To solve the above technical problem, the present application provides an aluminum alloy processing method by accumulative roll bonding, contact heating and artificial aging. The aluminum alloy material is pre-deformed by the accumulative roll bonding method, the plate is directly heated by using the upper and lower flat dies preheated to a specific temperature by using a contact heating device, the aluminum alloy is solution treated by heat conduction, the heating to near the solution temperature is achieved in 15s-20s, the solution treatment is completed within 25s-35s, and the time to reach the aging peak in the artificial aging process is shortened to 18h-20h, while the strength and hardness of the aluminum alloy are improved without loss of elongation.

[0011] The present application discloses an aluminum alloy processing method by accumulative roll bonding, contact heating and artificial aging, which adopts the following technical scheme:

[0012] The aluminum alloy processing method by accumulative roll bonding, contact heating and artificial aging comprises the following steps,

[0013] (1) homogenizing treatment of the aluminum alloy material;

[0014] (2) cleaning 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;

[0015] (3) pre-deforming the aluminum alloy material by accumulative roll bonding, the accumulative roll bonding times of the aluminum alloy material are 0-5 times, the reduction of single pass rolling is 20%-60%, and water quenching treatment is performed after the accumulative roll bonding is completed;

[0016] (4) preheating the upper and lower dies 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 dies for contact heating to realize solution treatment;

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

[0018] (6) transferring the aluminum alloy material after stamping quenching to a heating furnace for artificial aging treatment.

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

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

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

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

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

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

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

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

[0027] Preferably, in step (3), the material obtained from the previous pass is cut in the middle to the same size, and the same process steps are repeated, and step (2) is performed before each rolling.

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

[0029] The present application applies pre-deformation to the aluminum alloy material by the method of accumulative roll bonding, uses a contact heating device, directly heats the plate by using the upper and lower flat dies preheated to a specific temperature, and performs solution treatment on the aluminum alloy by the method of heat conduction, thereby quickly completing the solution treatment, improving the production efficiency, and improving the strength and hardness of the aluminum alloy without losing the elongation. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The figure is a schematic diagram of the accumulative roll bonding step of the present application;

[0031] Figure 2 The figure is a comparison of the peak aging of the contact heating process of the present application and the solution process of the prior art using a heating furnace. DETAILED DESCRIPTION

[0032] The present application will be further described below in conjunction with the drawings and specific embodiments so that those skilled in the art can better understand the present application and implement it. Obviously, the described embodiments are only a part of the embodiments of the present application and are not all the embodiments. It should be understood that the specific embodiments are only used to explain the present application and the embodiments are not limiting to the present application.

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

[0034] In the present application, unless otherwise specified, the terms "comprising" and / or "including" used in the present application indicate the presence of the stated features, integers, steps, operations, but do not exclude the presence or addition of one or more other features, integers, steps, operations or combinations thereof.

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

[0036] In the present application, unless otherwise specified, the specific conditions not indicated in the embodiments are carried out according to the conventional conditions or the conditions recommended by the manufacturer.

[0037] In the present application, unless otherwise specified, the reagents or instruments used are not indicated by the manufacturer, and are conventional products that can be obtained by commercial purchase.

[0038] Example 1

[0039] An aluminum alloy processing technology of accumulative roll-bonding, contact heating and artificial aging, specifically comprising the following steps:

[0040] (1) selecting 2mm thick 7075-T6 state aluminum alloy as the raw material, carrying out homogenization treatment at a temperature of 480℃ for 3h;

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

[0042] (3) applying pre-deformation to the aluminum alloy material by accumulative roll-bonding method, the rolling temperature is 250℃, the reduction of single pass is 50%, the number of roll-bonding is 0, and water quenching treatment is carried out after roll-bonding is completed;

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

[0044] (5) After the solid 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 pressure holding time is 30 s, and the pressure holding pressure is 100 KN;

[0045] (6) The plate material after the solid solution quenching is transferred to a heating furnace for 12 h of artificial aging treatment at a temperature of 120 DEG C.

[0046] Example 2

[0047] An accumulative roll bonding-contact heating-artificial aging aluminum alloy processing technology, specifically comprising the following steps:

[0048] (1) Selecting 2mm thick 7075-T6 state aluminum alloy as the original material, carrying out homogenization treatment at a temperature of 480 DEG C for 3h;

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

[0050] (3) The aluminum alloy material is pre-deformed by accumulative roll bonding, the rolling temperature is 250 DEG C, the single pass rolling reduction is 50%, the number of accumulative roll bonding is 0, and water quenching is carried out after the accumulative roll bonding is completed;

[0051] (4) The upper and lower dies of the contact heating device are preheated to 480 DEG C, and the aluminum alloy material is placed between the upper and lower dies for contact heating and solid solution treatment, the solid solution temperature is 480 DEG C, and the solid solution time is 30 s;

[0052] (5) After the solid 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 pressure holding time is 30 s, and the pressure holding pressure is 100 KN;

[0053] (6) The plate material after the solid solution quenching is transferred to a heating furnace for 12 h of artificial aging treatment at a temperature of 120 DEG C.

[0054] Example 3

[0055] An accumulative roll bonding-contact heating-artificial aging aluminum alloy processing technology, specifically comprising the following steps:

[0056] (1) Selecting 2mm thick 7075-T6 state aluminum alloy as the original material, carrying out homogenization treatment at a temperature of 480 DEG C for 3h;

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

[0058] (3) adopt the method of accumulative roll bonding to the aluminum alloy material to apply pre-deformation, rolling temperature is 250℃, single pass rolling reduction is 50%, the number of roll bonding is 0, after the completion of roll bonding, water quenching treatment is carried out;

[0059] (4) the upper and lower dies of the contact heating device are preheated to 480℃, the aluminum alloy material is placed between the upper and lower dies for contact heating and solid solution treatment, the solid solution temperature is 480℃, the solid solution time is 30s;

[0060] (5) after the completion of solid solution treatment, 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 30s, the holding pressure is 100KN;

[0061] (6) the solid solution quenched sheet is transferred to the heating furnace for 20h artificial aging treatment at 120℃.

[0062] Example 4

[0063] An accumulative roll bonding-contact heating-artificial aging aluminum alloy processing technology, specifically comprising the following steps:

[0064] (1) select 2mm thick 7075-T6 state aluminum alloy as the original material, carry out homogenization treatment at 480℃ for 3h;

[0065] (2) the surface of the aluminum alloy material is cleaned with acetone and copper wire brush to remove the surface oxidation layer and dirt until the surface is clean and smooth;

[0066] (3) adopt the method of accumulative roll bonding to the aluminum alloy material to apply pre-deformation, rolling temperature is 250℃, single pass rolling reduction is 50%, the number of roll bonding is 0, after the completion of roll bonding, water quenching treatment is carried out;

[0067] (4) the upper and lower dies of the contact heating device are preheated to 480℃, the aluminum alloy material is placed between the upper and lower dies for contact heating and solid solution treatment, the solid solution temperature is 480℃, the solid solution time is 30s;

[0068] (5) after the completion of solid solution treatment, 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 30s, the holding pressure is 100KN;

[0069] (6) the solid solution quenched sheet is transferred to the heating furnace for 24h artificial aging treatment at 120℃.

[0070] Example 5

[0071] An accumulative roll bonding-contact heating-artificial aging aluminum alloy processing technology, specifically comprising the following steps:

[0072] (1) Select 2mm thick 7075-T6 aluminum alloy as the original material, homogenization treatment at 480℃ for 3h;

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

[0074] (3) The cumulative roll bonding method is used to apply pre-deformation to the aluminum alloy material, the rolling temperature is 250℃, the single pass rolling reduction is 50%, the number of roll bonding is 1, and the water quenching treatment is carried out after the roll bonding is completed;

[0075] (4) The upper and lower dies of the contact heating device are preheated to 480℃, and the aluminum alloy material is placed between the upper and lower dies for contact heating and solid solution treatment, the solid solution temperature is 480℃, and the solid solution time is 30s;

[0076] (5) After the solid solution treatment, 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 30s, and the holding pressure is 100KN;

[0077] (6) The solid solution quenched sheet is transferred to the heating furnace for 18h artificial aging treatment at 120℃.

[0078] Example 6

[0079] A cumulative roll bonding-contact heating-artificial aging aluminum alloy processing technology, specifically comprising the following steps:

[0080] (1) Select 2mm thick 7075-T6 aluminum alloy as the original material, homogenization treatment at 480℃ for 3h;

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

[0082] (3) The cumulative roll bonding method is used to apply pre-deformation to the aluminum alloy material, the rolling temperature is 250℃, the single pass rolling reduction is 50%, the number of roll bonding is 1, and the water quenching treatment is carried out after the roll bonding is completed;

[0083] (4) The upper and lower dies of the contact heating device are preheated to 480℃, and the aluminum alloy material is placed between the upper and lower dies for contact heating and solid solution treatment, the solid solution temperature is 480℃, and the solid solution time is 30s;

[0084] (5) After the solid solution treatment, 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 30s, and the holding pressure is 100KN;

[0085] (6) The solution-quenched sheet material is transferred to a heating furnace for 20 h of artificial aging treatment at a temperature of 120°C.

[0086] Example 7

[0087] An accumulative roll bonding-contact heating-artificial aging aluminum alloy processing technology, specifically comprising the following steps:

[0088] (1) Selecting 2mm-thick 7075-T6 aluminum alloy as the raw material, homogenizing treatment is performed at a temperature of 480°C for 3h;

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

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

[0091] (4) The upper and lower dies of the contact heating device are preheated to 480°C, and the aluminum alloy material is placed between the upper and lower dies 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 pressure time is 30s, and the holding pressure is 100KN;

[0093] (6) The solution-quenched sheet material is transferred to a heating furnace for 24 h of artificial aging treatment at a temperature of 120°C.

[0094] Example 8

[0095] An accumulative roll bonding-contact heating-artificial aging aluminum alloy processing technology, specifically comprising the following steps:

[0096] (1) Selecting 2mm-thick 7075-T6 aluminum alloy as the raw material, homogenizing treatment is performed at a temperature of 480°C for 3h;

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

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

[0099] (4) The upper and lower molds of the contact heating device are preheated to 480°C, and the aluminum alloy material is placed between the upper and lower molds for contact heating and solid solution treatment, with a solid solution temperature of 480°C and a solid solution time of 30s;

[0100] (5) After the solid 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, with a holding time of 30s and a holding pressure of 100KN;

[0101] (6) The solid solution quenched sheet is transferred to a heating furnace for 16h artificial aging treatment at a temperature of 120°C

[0102] Example 9

[0103] An aluminum alloy processing technology of accumulative roll bonding-contact heating-artificial aging, specifically comprising the following steps:

[0104] (1) Select 2mm thick 7075-T6 state aluminum alloy as the original material, and perform homogenization treatment at a temperature of 480°C for 3h;

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

[0106] (3) Pre-deformation is applied to the aluminum alloy material by accumulative roll bonding, with a rolling temperature of 250°C, a single pass rolling reduction of 50%, and 2 times of accumulative rolling, followed by water quenching treatment;

[0107] (4) The upper and lower molds of the contact heating device are preheated to 480°C, and the aluminum alloy material is placed between the upper and lower molds for contact heating and solid solution treatment, with a solid solution temperature of 480°C and a solid solution time of 30s;

[0108] (5) After the solid 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, with a holding time of 30s and a holding pressure of 100KN;

[0109] (6) The solid solution quenched sheet is transferred to a heating furnace for 18h artificial aging treatment at a temperature of 120°C.

[0110] Example 10

[0111] An aluminum alloy processing technology of accumulative roll bonding-contact heating-artificial aging, specifically comprising the following steps:

[0112] (1) Select 2mm thick 7075-T6 state aluminum alloy as the original material, and perform homogenization treatment at a temperature of 480°C for 3h;

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

[0114] (3) The aluminum alloy material is pre-deformed by cumulative roll bonding, the rolling temperature is 250°C, the reduction of a single pass is 50%, the number of cumulative roll bonding is 2, and water quenching is performed after the cumulative roll bonding is completed;

[0115] (4) The upper and lower dies of the contact heating device are preheated to 480°C, and the aluminum alloy material is placed between the upper and lower dies for contact heating and solid solution treatment, the solid solution temperature is 480°C, and the solid solution time is 30s;

[0116] (5) After the solid 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 30s, and the holding pressure is 100KN;

[0117] (6) The solid solution quenched sheet is transferred to a heating furnace for 20h artificial aging treatment at 120°C.

[0118] Comparative Example 1

[0119] An aluminum alloy processing technology of cumulative roll bonding-contact heating-artificial aging, specifically comprising the following steps:

[0120] (1) Select 2mm thick 7075-T6 state aluminum alloy as the original material, and perform homogenization treatment at 480°C for 3h;

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

[0122] (3) The aluminum alloy material is pre-deformed by cumulative roll bonding, the rolling temperature is 250°C, the reduction of a single pass is 50%, the number of cumulative roll bonding is 1, and water quenching is performed after the cumulative roll bonding is completed;

[0123] (4) The upper and lower dies of the contact heating device are preheated to 480°C, and the aluminum alloy material is placed between the upper and lower dies for contact heating and solid solution treatment, the solid solution temperature is 480°C, and the solid solution time is 30s;

[0124] (5) After the solid 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 30s, and the holding pressure is 100KN;

[0125] (6) The solid solution quenched sheet is transferred to a heating furnace for 10h artificial aging treatment at 120°C.

[0126] Comparative Example 2

[0127] An accumulative roll bonding-contact heating-artificial aging aluminum alloy processing technology, specifically comprising the following steps:

[0128] (1) Select 2mm thick 7075-T6 state aluminum alloy as the original material, and perform homogenization treatment at a temperature of 480℃ for 3h;

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

[0130] (3) The aluminum alloy material is pre-deformed by using the accumulative roll bonding method, the rolling temperature is 250℃, the reduction of a single pass is 50%, the number of accumulative roll bonding is 1, and water quenching treatment is performed after the accumulative roll bonding is completed;

[0131] (4) The upper and lower molds of the contact heating device are preheated to 480℃, and the aluminum alloy material is placed between the upper and lower molds for contact heating and solid solution treatment, the solid solution temperature is 480℃, and the solid solution time is 30s;

[0132] (5) After the solid 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 30s, and the holding pressure is 100KN;

[0133] (6) The solid solution quenched sheet is transferred to a heating furnace for 26h artificial aging treatment at a temperature of 120℃.

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

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

[0136]

[0137]

[0138] The aluminum alloy material after accumulative roll bonding quenching has a large deformation, has a certain deformation energy storage, and needs to strictly control the rolling temperature, feeding speed and pressing amount of the roll bonding process, reduce the bending deformation, and needs to be straightened, polished and trimmed before contact heating, which is not conducive to production efficiency. Therefore, the key point of the present application is:

[0139] 1) The process of the present application releases the deformation energy after contact heating solid solution treatment and aging treatment, so that the pre-deformed alloy completes recrystallization, the grain is obviously refined, the material strength is effectively improved, and high-density dislocations are introduced by roll bonding, which accelerates the aging precipitation speed, so that the peak aging time can be shortened.

[0140] 2) The contact heating has a fast heating rate, the second phase in the aluminum alloy substrate is quickly dissolved, so that the supersaturation of the solid solution increases, and in the subsequent artificial aging process, the number of precipitated phases is more, the distribution is more uniform, and the size is more fine, so that the performance of the contact heating sample after aging treatment is better than that of the T6 sample.

[0141] 3) The artificial aging treatment at 100-200°C is slower than the existing natural aging process at room temperature, so the aging period is longer. The artificial aging at 120°C using the heating furnace 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 aluminum alloy material is processed by the contact heating method used herein, and in addition to the time required for heating and solid solution of the aluminum alloy being greatly shortened, the yield strength and tensile strength of the aluminum alloy material can exceed the original T6 state aluminum alloy strength after only 12h of artificial aging process. The time to reach peak aging in the artificial aging process can be shortened from 24h required by the traditional process to 20h. As can be seen from Examples 5-7, after introducing the accumulative pack 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 the elongation is not lost. As can be seen from Examples 8-10, when the accumulative pack rolling number is increased to 2 passes, the time to reach peak aging in the artificial aging process can be further shortened to 18h. This is because there is a precipitated strengthening effect of the phase in the aging process of the aluminum alloy, and the fine precipitated phase is uniformly distributed in the aluminum alloy substrate, so that the strength and hardness of the aluminum alloy increase. With the increase of the aging time, the number of precipitated phases increases, and the strengthening effect increases until the peak aging time. In addition, if the aging time is continuously prolonged, as shown in Comparative Examples 1-2, the aluminum alloy shows over-aging phenomenon, the phase of the precipitated phase changes, the size of the phase coarsens, and the strengthening effect is obviously weakened, so the strength and hardness decrease. Therefore, the artificial aging in the method of the present application is strictly controlled to be 12-24h.

[0143] As shown in Figure 2 , the existing heating furnace solid solution treatment method has a slow heating rate of the heating furnace, and the heating and solid solution treatment time usually needs 10-40min. The aging treatment usually needs to be kept in the heating furnace for at least 24h to reach the peak aging. The contact heating method of the present application can complete the heating to near the solid solution temperature in 15-20s, and the solid solution treatment can be completed in 25-35s. The time to reach the peak aging of the aluminum alloy material after the accumulative pack rolling-contact heating and artificial aging can be shortened to 18-20h.

[0144] In addition, it is found in the study that with the increase of the aluminum alloy accumulative rolling passes, the strength and hardness of the aluminum alloy also increase, as shown in Examples 11-13, which is due to the grain refinement and deformation strengthening of the material. However, with the increase of the accumulative rolling passes, the grain growth rate and the dislocation accumulation trend also increase. When the passes increase to a certain extent, the strength and hardness of the aluminum alloy no longer increase, and even decrease. Although the increase of the accumulative rolling passes can improve the strength and hardness of the aluminum alloy, it also increases the inclusion of the oxide on the surface of the alloy, as shown in Comparative Example 3. The bending degree of the aluminum alloy increases, and cracking phenomenon easily occurs, which is not conducive to the subsequent contact heating. Therefore, the accumulative rolling process needs to be strictly controlled, and the accumulative rolling passes should not be too many.

[0145] The technical solutions provided by the present application are described in detail above, and the principles and implementation modes of the present application are described by applying specific examples. The above description of the examples is only used to help understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation modes and application ranges will be changed. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. An aluminum alloy processing method by accumulative roll bonding, contact heating, and artificial aging, characterized by, The method comprises the following steps: (1) homogenizing treatment is performed on the aluminum alloy material; the homogenizing temperature of the aluminum alloy material is 450-550 DEG C, and the holding time is 1-12 h; the thickness of the aluminum alloy material is 1.5-2.5 mm; (2) the surface of the aluminum alloy material is cleaned to remove the oxide layer and oil stains on the surface until the surface is clean and smooth; (3) pre-deformation is applied to the aluminum alloy material by using the method of accumulative roll bonding; the accumulative roll bonding times of the aluminum alloy material are 0-5, and the reduction of single pass rolling is 20-60%; after the accumulative roll bonding is completed, water quenching treatment is performed; the rolling temperature of the aluminum alloy material is 200-350 DEG C; (4) the upper and lower dies of a contact heating device are preheated to the solid solution temperature of the aluminum alloy material; the aluminum alloy material is placed between the upper and lower dies for contact heating to realize solid solution treatment; the solid solution temperature of the aluminum alloy material ranges from 450 DEG C to 550 DEG C, and the solid solution time is 25-35 s; (5) after the solid 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 die closing and pressure maintaining time in the stamping forming process is 25-35 s, and the pressure maintaining pressure is 80-120 KN; (6) the aluminum alloy material after stamping quenching is transferred to a heating furnace for artificial aging treatment; the artificial aging temperature of the aluminum alloy material is 100-200 DEG C, and the aging time is 12-24 h.

2. The aluminum alloy processing method by accumulative roll bonding, contact heating, and artificial aging according to claim 1, characterized by, In step (3), the accumulative roll bonding times of the aluminum alloy material are 2, and the reduction of single pass rolling is 50%.

3. The aluminum alloy processing method by accumulative roll bonding, contact heating and artificial aging according to claim 1, characterized by, In step (2), the surface cleaning of the aluminum alloy material is performed by using acetone and a copper wire brush.

4. The aluminum alloy processing method by accumulative roll bonding, contact heating, and artificial aging according to claim 1, characterized by, In step (3), the material obtained after the last pass rolling is cut into the same size from the middle, and the same process steps are repeated; the step (2) is performed before each rolling.

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