Method for preparing H24 aluminum alloy by regenerating aluminum alloy waste

Abstract

The invention relates to the technical field of aluminum alloy, and discloses a method for preparing H24 aluminum alloy through regeneration of aluminum alloy waste. According to the method, the aluminum alloy waste obtained through recycling is utilized, the aluminum alloy components and the preparation technology are optimized, and the H24 aluminum alloy which is high in mechanical property and has plasticity is obtained. The H24 aluminum alloy prepared by the method comprises the following components in percentage by weight: 0.379% of Fe, 0.7% of Si, 0.10% of Cu, 1.09% of Mn, 0.008% of Mg, 0.105% of Zn, 0.03% of Ti, and the balance of Al and less than 0.05% of impurities. The tensile strength of the H24 aluminum alloy is larger than or equal to 200 MPa, the yield strength of the H24 aluminum alloy is larger than or equal to 180 MPa, the ductility of the H24 aluminum alloy is larger than or equal to 10, and the requirements of industrial application for the H24 aluminum alloy with high mechanical property and plasticity can be met.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloys, and in particular to a method for preparing H24 aluminum alloy by regenerating aluminum alloy waste. Background Art

[0002] As a renewable resource, the application of recycled aluminum in the field of architectural decoration has significant environmental advantages and market potential. Recycled aluminum products have broad application prospects in many fields, and the main application areas include new energy vehicles, motorcycles, electronic information, machinery manufacturing, and building hardware industries. It is worth noting that the promotion and use of recycled aluminum can not only promote the low-carbon transformation of the non-ferrous metal industry and reduce the adverse impact on the environment, but also contribute to the sustainable development goals. In addition, recycled aluminum materials have been widely used in the construction field due to their excellent physical and chemical properties, such as lightweight and high strength. Recycled aluminum alloys are mainly used to produce cast aluminum alloy products and die-cast aluminum alloy products. Their application fields have covered automobiles, motorcycles, mechanical equipment, communication equipment, electronic appliances, hardware and lamps, etc. The use of recycled aluminum alloy waste to produce recycled aluminum alloys can greatly reduce production costs and environmental pressures.

[0003] At present, the strength of the existing H24 aluminum alloy is not high (slightly higher than industrial pure aluminum), and it cannot be strengthened by heat treatment. Therefore, the cold working method is used to improve its mechanical properties: it has high plasticity in the annealed state, and good plasticity during semi-cold hardening, but low plasticity during cold hardening and poor machinability. Therefore, an H24 aluminum alloy with both plasticity and mechanical properties is urgently needed in industrial applications. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem of how to effectively utilize aluminum alloy waste to prepare H24 aluminum alloy with high mechanical properties in the prior art, and provide a method for preparing H24 aluminum alloy by recycling aluminum alloy waste. The method utilizes aluminum alloy waste, controls annealing temperature and annealing time, and then obtains H24 aluminum alloy with high mechanical properties and plasticity and plate shape that meets standards through multiple cold rolling.

[0005] In order to achieve the above-mentioned object, the first aspect of the present invention provides a method for preparing H24 aluminum alloy by recycling aluminum alloy waste. Based on the total weight, the H24 aluminum alloy comprises: 0.379 wt% Fe, 0.7 wt% Si, 0.1 wt% Cu, 1.09 wt% Mn, 0.008 wt% Mg, 0.105 wt% Zn, 0.03 wt% Ti, the balance being Al and less than 0.05 wt% impurities; The method comprises the following steps: (1) Casting and rolling: Aluminum alloy scrap is cast and rolled to obtain cast and rolled coils, wherein the casting and rolling speed is 400-700 mm / min and the front box temperature is 680-700°C; (2) Homogenizing annealing: The cast-rolled coil obtained in step (1) is cooled and then annealed. The annealing process includes three stages performed in sequence: S1, first annealing stage: heating the cast-rolled coil to 450-500°C; S2, second annealing stage: keeping the cast-rolled coil warm for 800-1000 min; S3, third annealing stage: cooling the cast-rolled coil to room temperature; (3) Rough rolling: the product obtained in step (2) is subjected to four cold rolling passes, wherein the processing rates of the four cold rolling passes are 20-40%, 40-60%, 40-60% and 30-50% respectively; (4) intermediate rolling: subjecting the product obtained in step (3) to a single cold rolling, wherein the single cold rolling has a processing rate of 40-50%; (5) Finish rolling: the product obtained in step (4) is subjected to a single cold rolling, wherein the single cold rolling has a processing rate of 45-55%; (6) Finished product annealing: S1. Raise the temperature in the furnace to 200-250℃ by timing and temperature setting; S2, rapidly heating the material obtained in step (5) to 270-300°C by furnace gas; S3. After the material reaches the process insulation temperature of 270-300°C, it is subjected to insulation treatment for 800-1000 minutes.

[0006] Preferably, in step (1), the thickness of the cast-rolled coil is 10-11 mm, the coil diameter is 1670-2430 mm, the process gap is ≤6 mm, the edge difference is ≤0.03%, and the center convexity is ≤0.04%.

[0007] Preferably, in S1 described in step (2), the conditions of the first annealing stage further include: the frequency of the circulation fan is 95% of the maximum frequency, the frequency of the purge fan is 80% of the maximum frequency, and the frequency of the oil removal fan is 50% of the maximum frequency; In step (2) S2, the conditions of the second annealing stage further include: the frequency of the circulation fan is 95% of the maximum frequency, the frequency of the purge fan is 30% of the maximum frequency, and the frequency of the oil removal fan is 15% of the maximum frequency; In S3 described in step (2), the conditions of the third annealing stage also include: the frequency of the circulation fan is 80% of the maximum frequency, the frequency of the purge fan is 30% of the maximum frequency, and the frequency of the oil removal fan is 15% of the maximum frequency.

[0008] Preferably, in step (3), the rough rolling conditions include: the light transmittance of the rolling oil used is ≥90%, and the oil temperature is 40-50°C.

[0009] Preferably, during the rough rolling process, the conditions of the first pass include: the unwinding tension is 6-10N / mm 2 , curling tension is 19-25N / mm 2 ; The conditions for the second pass include: unwinding tension of 17-23N / mm 2 , curling tension is 25-31N / mm 2 ; The conditions for the third pass include: unwinding tension is 22-28N / mm 2 , curling tension is 29-35N / mm 2 ; The fourth pass conditions include: unwinding tension is 27-33N / mm 2 , curling tension is 32-38N / mm 2 .

[0010] Preferably, in step (4) and step (5), the conditions of the intermediate rolling and the finish rolling include: the light transmittance of the rolling oil used is ≥ 92%, and the oil temperature is 40-50°C.

[0011] Preferably, the intermediate rolling conditions also include: the entrance tension is 20-26N / mm 2 , outlet tension is 25-31N / mm 2 .

[0012] Preferably, the conditions for the finish rolling also include: the entrance tension is 23-29N / mm 2 , outlet tension is 29-35N / mm 2 .

[0013] Preferably, the method further comprises: before performing intermediate rolling, trimming the product obtained after the rough rolling.

[0014] Preferably, the trimming conditions include: unwinding tension is 3710-3930N / mm 2 , the shear speed is 220-320m / min.

[0015] Preferably, the preparation method further comprises: straightening the product obtained in step (5).

[0016] Preferably, the tension straightening conditions include: unwinding tension is 23-29N / mm 2 , winding tension is 27-33N / mm 2 , elongation is 0.3-0.5%, speed is 290-350m / min.

[0017] Preferably, the preparation method further comprises: shearing the product obtained after stretching and leveling.

[0018] Preferably, the shearing conditions include: shearing speed ≥ 300m / min, winding unit tension 20-25N / m 2 , the tension gradient is 95-105%, and the surface pressure value is 93-97N.

[0019] The method for preparing H24 aluminum alloy by recycling aluminum alloy waste disclosed in the present invention utilizes aluminum alloy waste, designs and optimizes the composition of H24 aluminum alloy, controls the annealing temperature and annealing time in the preparation process of H24 aluminum alloy, and then performs multiple cold rolling. Without affecting the plasticity of H24 aluminum alloy, its compressive strength and yield strength are improved, thereby realizing the recycling of aluminum alloy waste and significantly reducing costs. At the same time, it can meet the industrial application requirements for H24 aluminum alloy with high mechanical properties and plate shape that meets standards. DETAILED DESCRIPTION

[0020] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0021] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0022] The method for preparing H24 aluminum alloy by recycling aluminum alloy waste of the present invention comprises, based on the total weight, the H24 aluminum alloy comprising: 0.379 wt% Fe, 0.7 wt% Si, 0.1 wt% Cu, 1.09 wt% Mn, 0.008 wt% Mg, 0.105 wt% Zn, 0.03 wt% Ti, the balance being Al and less than 0.05 wt% impurities; The preparation method comprises the following steps: (1) Casting and rolling: Aluminum alloy scrap is cast and rolled to obtain cast and rolled coils, wherein the casting and rolling speed is 400-700 mm / min and the front box temperature is 680-700°C; (2) Homogenizing annealing: The cast-rolled coil obtained in step (1) is cooled and then annealed. The annealing process includes three stages performed in sequence: S1, first annealing stage: heating the cast-rolled coil to 450-500°C; S2, second annealing stage: keeping the cast-rolled coil warm for 800-1000 min; S3, third annealing stage: cooling the cast-rolled coil to room temperature;

[0023] (3) Rough rolling: the product obtained in step (2) is subjected to four cold rolling passes, wherein the processing rates of the four cold rolling passes are 20-40%, 40-60%, 40-60% and 30-50% respectively; (4) intermediate rolling: subjecting the product obtained in step (3) to a single cold rolling, wherein the single cold rolling has a processing rate of 40-50%; (5) Finish rolling: the product obtained in step (4) is subjected to a single cold rolling, wherein the single cold rolling has a processing rate of 45-55%; (6) Finished product annealing: S1. Raise the temperature in the furnace to 200-250℃ by timing and temperature setting; S2, rapidly heating the material obtained in step (5) to 270-300°C by furnace gas; S3. After the material reaches the process insulation temperature of 270-300°C, it is subjected to insulation treatment for 800-1000 minutes.

[0024] In the present invention, the aluminum alloy scrap can be recycled Class A scrap (such as H24 series aluminum alloy scrap, H26 series aluminum alloy scrap, etc.). Since Class A scrap generally contains Fe, Si, Cu, Mn, Mg and Zn elements, it is supplemented with certain pure metals of the above elements and / or intermediate alloys obtained by combinations of the above elements, such as aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-magnesium alloys and aluminum-iron alloys. As long as the content of the above elements can be controlled within the range described in the present invention during the casting and rolling process, it can be used.

[0025] In the present invention, when the H24 aluminum alloy contains the above-mentioned elements in the composition content, it can provide casting fluidity and mechanical properties of the alloy that meet the casting and rolling forming process.

[0026] In the present invention, the H24 aluminum alloy has a lower Si content, which avoids the formation of excessive α (Al12 Fe3Si2) phase or β(Al9Fe2Si3) phase, while preventing the Si element from destroying the dissolution of the Mn element, thereby avoiding affecting the plasticity when improving the mechanical strength of the H24 aluminum alloy.

[0027] In some embodiments, during the casting process, the diameter of the casting roll may be of the Φ850 series or the Φ1003 series, and the length of the casting zone may be 38-42 mm.

[0028] In some embodiments, in step (1), the casting process may further include: adding Al-Ti5-B grain refiner in the flow channel after the static furnace in the reverse direction of the metal fluid flow. In the present invention, the amount of the Al-Ti5-B grain refiner can be a conventional amount in the art, as long as the plate surface of the cast-rolled coil is free of coarse grains.

[0029] In a more preferred embodiment, in step (1), the thickness of the cast-rolled coil is 10-11 mm, the coil diameter is 1670-2430 mm, the process gap is ≤6 mm, the edge difference is ≤0.03%, and the center convexity is ≤0.04%.

[0030] In the present invention, in step (2) S1, the first annealing stage may further include: heating the cast-rolled coil to 150-250°C, preferably 200°C; then keeping the cast-rolled coil at a constant temperature for 100-150 minutes, preferably 120 minutes; wherein the frequency of the circulating fan is 95% of the maximum frequency, the frequency of the purge fan is 80% of the maximum frequency, and the frequency of the oil removal fan is 50% of the maximum frequency; In step (2) S2, the second annealing stage may further include: heating the cast-rolled coil to 500-550°C, preferably 500°C; wherein the frequency of the circulating fan is 95% of the maximum frequency, the frequency of the purge fan is 30% of the maximum frequency, and the frequency of the oil removal fan is 15% of the maximum frequency; In S3 described in step (2), the third annealing section may further include: cooling the cast-rolled coil to 450-480°C, preferably 460°C; then maintaining the cast-rolled coil at a constant temperature for 850-950 minutes, preferably 900 minutes; wherein the frequency of the circulating fan is 80% of the maximum frequency, the frequency of the purge fan is 30% of the maximum frequency, and the frequency of the oil removal fan is 15% of the maximum frequency.

[0031] In the method of the present invention, the annealing can be performed in an annealing furnace.

[0032] In the present invention, by controlling the process conditions of homogenization annealing, the anisotropy of the H24 aluminum alloy and the internal stress inside the alloy can be partially eliminated through the recovery process and the recrystallization process, thereby improving the plasticity of the H24 aluminum alloy while retaining the mechanical strength of the H24 aluminum alloy, thereby ensuring that the H24 aluminum alloy can withstand subsequent cold rolling deformation.

[0033] In the present invention, in step (3), the conditions for the rough rolling include: the light transmittance of the rolling oil used is ≥ 90%, and the oil temperature is 40-50°C.

[0034] In the method described in the present invention, during the rough rolling process, the crown of the working roll can be 0.1 mm and the roughness can be 0.70-0.80 um.

[0035] In the method of the present invention, during the rough rolling process, the conditions of the first pass include: the unwinding tension is 6-10N / mm 2 , curling tension is 19-25N / mm 2 ; The conditions for the second pass include: unwinding tension of 17-23N / mm 2 , curling tension is 25-31N / mm 2 ; The conditions for the third pass include: unwinding tension is 22-28N / mm 2 , curling tension is 29-35N / mm 2 ; The fourth pass conditions include: unwinding tension is 27-33N / mm 2 , curling tension is 32-38N / mm 2 .

[0036] In the present invention, the thickness of the H24 aluminum alloy reaches the requirements of industrial application through multiple cold rolling passes. At the same time, the method described in the present invention controls the cold rolling passes and process parameters to make the H24 aluminum alloy undergo work hardening, thereby improving the mechanical strength of the H24 aluminum alloy.

[0037] In some embodiments, the preparation method further comprises: trimming the product obtained in step (3), wherein the trimming can be performed on a rewinding machine, wherein the width of the H24 aluminum alloy is reduced by 50-70 mm, and the cross section is free of cracks and burrs after trimming.

[0038] In a preferred embodiment, the trimming conditions include: unwinding tension of 3710-3930 N / mm 2 , the shear speed is 220-320m / min.

[0039] In the method of the present invention, in step (4) and step (5), the conditions of the intermediate rolling and the finish rolling include: the light transmittance of the rolling oil used is ≥92%, and the oil temperature is 40-50°C.

[0040] In a more preferred embodiment, in step (4) and step (5), the material temperature of the intermediate rolling and the finishing rolling can be 80-120°C.

[0041] In the present invention, the intermediate rolling conditions also include: the entrance tension is 20-26N / mm 2 , outlet tension is 25-31N / mm 2 ; In the present invention, the conditions for the finish rolling also include: the entrance tension is 23-29N / mm 2 , outlet tension is 29-35N / mm 2 .

[0042] In the present invention, the thickness of the H24 aluminum alloy meets the different requirements of industrial applications through multiple cold rolling passes. At the same time, the method described in the present invention controls the cold rolling passes and process parameters to cause the H24 aluminum alloy to undergo work hardening, thereby improving the mechanical strength of the H24 aluminum alloy.

[0043] In the method described in the present invention, the finished product annealing also includes: using a small sample to simulate the constant temperature, taking three samples of A1, A2, and A3, the size of A4 paper, from the corresponding thickness of the finished finished material, and making three samples that meet the mechanical experiment standard for the three samples to conduct simulation experiments at different temperatures. The final material annealing temperature is determined by the mechanical properties of the small sample, and the temperature of the small sample with high mechanical properties is the final annealing temperature, and the temperature range is 270-300°C.

[0044] In the present invention, the mechanical properties of the H24 aluminum alloy can be further improved through the finished product annealing.

[0045] In some embodiments, the preparation method further comprises: subjecting the product obtained in step (5) to stretching and straightening, and the stretching and straightening can be performed on a stretching and straightening machine, wherein the roller diameter of the bending and straightening roller can be φ25 or φ30.

[0046] In a more preferred embodiment, after straightening, the surface of the H24 aluminum alloy has no cracks, holes, wrinkles, bumps, particle marks, straightening marks, metal and non-metal indentations, and the H24 aluminum alloy plate has no intermediate waves, bubble waves and side waves, the number of waves per meter is ≤2, and the peak height is ≤2mm.

[0047] In a preferred embodiment, the tension straightening conditions include: the unwinding tension is 23-29N / mm 2 , winding tension is 27-33N / mm2 , elongation is 0.3-0.5%, speed is 290-350m / min.

[0048] In some embodiments, the preparation method further comprises: shearing the product obtained after stretching and leveling, wherein the shearing can be performed on a shearing machine.

[0049] In a preferred embodiment, the shearing conditions include: shearing speed ≥ 300 m / min, winding unit tension 20-25 N / m 2 , the tension gradient is 95-105%, and the surface pressure value is 93-97N.

[0050] The following examples further illustrate the method for preparing H24 aluminum alloy from aluminum alloy waste according to the present invention. The examples are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following examples.

[0051] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available.

[0052] Example 1

[0053] The composition and weight percentage of the prepared H24 aluminum alloy are as follows: Fe 0.379 wt%, Si 0.7 wt%, Cu 0.10 wt%, Mn 1.09 wt%, Mg 0.008 wt%, Zn 0.105 wt%, Ti 0.03 wt%, impurities of 0.05 wt% or less, and the balance is Al.

[0054] (1) Casting and rolling: The above-mentioned H24 series aluminum alloy scrap, H26 series aluminum alloy scrap, aluminum ingot, aluminum silicon alloy, aluminum copper alloy, aluminum magnesium alloy and aluminum iron alloy are cast and rolled, wherein the diameter of the casting roll used in the casting and rolling is Φ850 series, the length of the casting and rolling zone is 40 mm, the casting and rolling speed is 600 mm / min, the front box temperature is 690°C, and during the casting and rolling process, Al-Ti5-B grain refiner is added in the flow channel behind the static furnace in the opposite direction of the metal fluid flow; (2) Annealing: subjecting the cast-rolled coil obtained in step (1) to homogenous annealing, wherein the temperature and time requirements of each annealing section are shown in Table 1; Table 1

[0055] Among them, f1, f2 and f3 are the maximum operating frequencies of the circulation fan, the purge fan and the oil removal fan respectively; (3) Rough rolling: The annealed cast-rolled coil obtained in step (2) is subjected to four cold rolling passes, wherein the process parameters and pass processing rate of each cold rolling pass are shown in Table 2; Table 2

[0056] (4) Recoiling and trimming: The H24 aluminum alloy obtained in step (3) is trimmed on a recoiling machine, wherein the trimming conditions include: the uncoiling tension is 3800 N / mm 2 , the shearing speed is 270 m / min, and the width of the H24 aluminum alloy is reduced by 60 mm after trimming; (5) Intermediate rolling: The H24 aluminum alloy obtained in step (4) is subjected to a single cold rolling, wherein the process parameters and the processing rate of each cold rolling pass are shown in Table 3; Table 3

[0057] (6) Finish rolling: The H24 aluminum alloy obtained in step (5) is subjected to a single cold rolling, wherein the process parameters and the processing rate of each cold rolling pass are shown in Table 4; Table 4

[0058] (7) Finished product annealing: S1, raise the temperature in the furnace to 230°C by timing and temperature setting; S2, rapidly heating the material obtained in step (6) to 290° C. by furnace gas; S3, when the material reaches the process insulation temperature of 290°C, carry out insulation treatment for 900 minutes; (8) Straightening: The H24 aluminum alloy obtained in step (7) is straightened on a straightening machine, wherein the diameter of the bending straightening roll is φ25 and the unwinding tension is 26 N / mm. 2 , winding tension is 30N / mm 2 , elongation is 0.4%, speed is 320m / min; (9) Shearing: The H24 aluminum alloy obtained in step (8) is sheared on a shearing machine, wherein the shearing speed is 300 m / min and the winding unit tension is 23 N / m 2 , the tension gradient is 100%, and the surface pressure value is 95N.

[0059] Example 2

[0060] The composition and weight percentage of the prepared H24 aluminum alloy are as follows: Fe 0.379 wt%, Si 0.7 wt%, Cu 0.10 wt%, Mn 1.09 wt%, Mg 0.008 wt%, Zn 0.105 wt%, Ti 0.03 wt%, impurities of 0.05 wt% or less, and the balance is Al.

[0061] (1) Casting and rolling: The above-mentioned H24 series aluminum alloy scrap, H26 series aluminum alloy scrap, aluminum ingot, aluminum silicon alloy, aluminum copper alloy, aluminum magnesium alloy and aluminum iron alloy are subjected to cast and rolling, wherein the diameter of the casting roll used in the casting and rolling is Φ850 series, the length of the casting and rolling zone is 40 mm, the casting and rolling speed is 500 mm / min, the front box temperature is 680°C, and during the casting and rolling process, Al-Ti5-B grain refiner is added in the flow channel behind the static furnace in the opposite direction of the metal fluid flow direction; (2) Annealing: subjecting the cast-rolled coil obtained in step (1) to homogenous annealing, wherein the temperature and time requirements of each annealing section are shown in Table 5; Table 5

[0062] Among them, f1, f2 and f3 are the maximum operating frequencies of the circulation fan, the purge fan and the oil removal fan respectively; (3) Rough rolling: The annealed cast-rolled coil obtained in step (2) is subjected to four cold rolling passes, wherein the process parameters and pass processing rate of each cold rolling pass are shown in Table 6; Table 6

[0063] (4) Recoiling and trimming: The H24 aluminum alloy obtained in step (3) is trimmed on a recoiling machine, wherein the trimming conditions include: the uncoiling tension is 3800 N / mm 2 , the shearing speed is 270 m / min, and the width of the H24 aluminum alloy is reduced by 60 mm after trimming; (5) Intermediate rolling: The H24 aluminum alloy obtained in step (4) is subjected to two passes of cold rolling, wherein the process parameters and pass processing rates of each pass of cold rolling are shown in Table 7; Table 7

[0064] (6) Finish rolling: The H24 aluminum alloy obtained in step (5) is subjected to a single cold rolling, wherein the process parameters and the processing rate of each cold rolling pass are shown in Table 8; Table 8

[0065] (7) Finished product annealing: S1, raise the temperature in the furnace to 230°C by timing and temperature setting; S2, rapidly heating the material obtained in step (6) to 290° C. by furnace gas; S3, when the material reaches the process insulation temperature of 290°C, carry out insulation treatment for 900 minutes; (8) Straightening: The H24 aluminum alloy obtained in step (7) is straightened on a straightening machine, wherein the diameter of the bending straightening roll is φ25 and the unwinding tension is 26 N / mm. 2 , winding tension is 30N / mm 2 , elongation is 0.4%, speed is 320m / min; (9) Shearing: The H24 aluminum alloy obtained in step (8) is sheared on a shearing machine, wherein the shearing speed is 300 m / min and the winding unit tension is 23 N / m 2 , the tension gradient is 100%, and the surface pressure value is 95N.

[0066] Example 3 The composition and weight percentage of the prepared H24 aluminum alloy are as follows: Fe 0.379 wt%, Si 0.7 wt%, Cu 0.10 wt%, Mn 1.09 wt%, Mg 0.008 wt%, Zn 0.105 wt%, Ti 0.03 wt%, impurities of 0.05 wt% or less, and the balance is Al.

[0067] (1) Casting and rolling: The above-mentioned H24 series aluminum alloy scrap, H26 series aluminum alloy scrap, aluminum ingot, aluminum silicon alloy, aluminum copper alloy, aluminum magnesium alloy and aluminum iron alloy are cast and rolled, wherein the diameter of the casting roll used in the casting and rolling is Φ850 series, the length of the casting and rolling zone is 40 mm, the casting and rolling speed is 600 mm / min, the front box temperature is 690°C, and during the casting and rolling process, Al-Ti5-B grain refiner is added in the flow channel behind the static furnace in the opposite direction of the metal fluid flow; (2) Annealing: subjecting the cast-rolled coil obtained in step (1) to homogenous annealing, wherein the temperature and time requirements of each annealing stage are shown in Table 9; Table 9

[0068] Among them, f1, f2 and f3 are the maximum operating frequencies of the circulation fan, the purge fan and the oil removal fan respectively; (3) Rough rolling: The annealed cast-rolled coil obtained in step (2) is subjected to four cold rolling passes, wherein the process parameters and pass processing rate of each cold rolling pass are shown in Table 10; Table 10

[0069] (4) Recoiling and trimming: The H24 aluminum alloy obtained in step (3) is trimmed on a recoiling machine, wherein the trimming conditions include: the uncoiling tension is 3800 N / mm 2 , the shearing speed is 270 m / min, and the width of the H24 aluminum alloy is reduced by 60 mm after trimming; (5) Intermediate rolling: The H24 aluminum alloy obtained in step (4) is subjected to two passes of cold rolling, wherein the process parameters and pass processing rate of each pass of cold rolling are shown in Table 11; Table 11

[0070] 6) Finish rolling: The H24 aluminum alloy obtained in step (5) is subjected to a single cold rolling, wherein the process parameters and the processing rate of each cold rolling pass are shown in Table 12; Table 12

[0071] 7) Finished product annealing: S1, raise the temperature in the furnace to 230°C by timing and temperature setting; S2, rapidly heating the material obtained in step (6) to 290° C. by furnace gas; S3, when the material reaches the process insulation temperature of 290°C, carry out insulation treatment for 900 minutes; (8) Straightening: The H24 aluminum alloy obtained in step (7) is straightened on a straightening machine, wherein the diameter of the bending straightening roll is φ25 and the unwinding tension is 26 N / mm. 2 , winding tension is 30N / mm 2 , elongation is 0.4%, speed is 320m / min; (9) Shearing: The H24 aluminum alloy obtained in step (8) is sheared on a shearing machine, wherein the shearing speed is 300 m / min and the winding unit tension is 23 N / m 2 , the tension gradient is 100%, and the surface pressure value is 95N.

[0072] Comparative Example 1 This comparative example was implemented according to the method of Example 1, except that in step (1), the casting speed was 800 mm / min and the front box temperature was 650°C.

[0073] Comparative Example 2 This comparative example is implemented according to the method of Example 1, except that in step (2), the temperature and time requirements of each annealing section are shown in Table 13; Table 13

[0074] Among them, f1, f2 and f3 are the maximum operating frequencies of the circulation fan, the purge fan and the oil removal fan respectively.

[0075] Comparative Example 3 This comparative example was implemented according to the method of Example 1, except that in step (3), the process parameters and pass processing rate of each cold rolling pass are shown in Table 14.

[0076] Table 14

[0077] Test Case The mechanical properties of the H24 aluminum alloys prepared in Examples 1-3 and Comparative Examples 1-3 were tested using GB / T 228.1-2010. Three tensile pieces were measured for each H24 aluminum alloy and the average value was taken as the tensile test result. The results are shown in Table 15.

[0078] Table 15

[0079] It can be seen from the results in Table 7 that the present invention designs and optimizes the composition of the H24 aluminum alloy, controls the annealing conditions and the cold rolling process in the preparation process, and the H24 aluminum alloys prepared in Examples 1-3 have high mechanical properties and plasticity, with a tensile strength of ≥200 MPa, a yield strength of ≥180 MPa, and an elongation of ≥10; while the H24 aluminum alloys prepared in Comparative Examples 1 and 2 have mechanical properties and plasticity inferior to those of the H24 aluminum alloy of the present invention due to excessively high casting and rolling speeds and too low annealing temperatures, respectively. The H24 aluminum alloy prepared in Comparative Example 3 has fewer work hardening times, and although the plasticity is retained, the mechanical properties are inferior to those of the H24 aluminum alloy of the present invention, and cannot meet industrial application requirements.

[0080] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing H24 aluminum alloy by recycling aluminum alloy waste, characterized in that: Based on total weight, the H24 aluminum alloy contains: 0.379 wt% Fe, 0.7 wt% Si, 0.1 wt% Cu, 1.09 wt% Mn, 0.008 wt% Mg, 0.105 wt% Zn, 0.03 wt% Ti, the balance being Al and less than 0.05 wt% impurities; The method comprises the following steps: (1) Casting and rolling: Aluminum alloy scrap is cast and rolled to obtain cast and rolled coils, wherein the casting and rolling speed is 400-700 mm / min and the front box temperature is 680-700°C; (2) Homogenizing annealing: The cast-rolled coil obtained in step (1) is cooled and then annealed. The annealing process includes three stages performed in sequence: S1, first annealing stage: heating the cast-rolled coil to 450-500°C; S2, second annealing stage: keeping the cast-rolled coil warm for 800-1000 min; S3, third annealing stage: cooling the cast-rolled coil to room temperature; (3) Rough rolling: the product obtained in step (2) is subjected to four cold rolling passes, wherein the processing rates of the four cold rolling passes are 20-40%, 40-60%, 40-60% and 30-50% respectively; (4) intermediate rolling: subjecting the product obtained in step (3) to a single cold rolling, wherein the single cold rolling has a processing rate of 40-50%; (5) Finish rolling: the product obtained in step (4) is subjected to a single cold rolling to obtain a H24 aluminum alloy finished product, wherein the single cold rolling process rate is 45-55%; (6) Finished product annealing: S1. Raise the temperature in the furnace to 200-250℃ by timing and temperature setting; S2, rapidly heating the material obtained in step (5) to 270-300°C by furnace gas; S3. After the material reaches the process insulation temperature of 270-300°C, it is subjected to insulation treatment for 800-1000 minutes.

2. The method according to claim 1, characterized in that In step (1), the thickness of the cast-rolled coil is 10-11 mm, the coil diameter is 1670-2430 mm, the process gap is ≤6 mm, the edge difference is ≤0.03%, and the center convexity is ≤0.04%.

3. The method according to claim 1, characterized in that: In step (2) of S1, the conditions of the first annealing stage further include: the frequency of the circulation fan is 95% of the maximum frequency, the frequency of the purge fan is 80% of the maximum frequency, and the frequency of the oil removal fan is 50% of the maximum frequency; In step (2) S2, the conditions of the second annealing stage further include: the frequency of the circulation fan is 95% of the maximum frequency, the frequency of the purge fan is 30% of the maximum frequency, and the frequency of the oil removal fan is 15% of the maximum frequency; In S3 described in step (2), the conditions of the third annealing stage also include: the frequency of the circulation fan is 80% of the maximum frequency, the frequency of the purge fan is 30% of the maximum frequency, and the frequency of the oil removal fan is 15% of the maximum frequency.

4. The method according to claim 1, characterized in that In step (3), the rough rolling conditions include: the light transmittance of the rolling oil used is ≥90%, and the oil temperature is 40-50°C.

5. The method according to claim 1 or 4, characterized in that: During the rough rolling process, the conditions of the first pass include: the unwinding tension is 6-10N / mm 2 , curling tension is 19-25N / mm 2 ; The conditions for the second pass include: unwinding tension of 17-23N / mm 2 , curling tension is 25-31N / mm 2 ; The conditions for the third pass include: unwinding tension is 22-28N / mm 2 , curling tension is 29-35N / mm 2 ; The fourth pass conditions include: unwinding tension is 27-33N / mm 2 , curling tension is 32-38N / mm 2 .

6. The method according to claim 1, characterized in that In step (4) and step (5), the conditions for the intermediate rolling and the finish rolling include: the light transmittance of the rolling oil used is ≥ 92%, and the oil temperature is 40-50°C.

7. The method according to claim 1 or 6, characterized in that: During the intermediate rolling process, the conditions for the cold rolling in one pass include: the entrance tension is 20-26N / mm 2 , outlet tension is 25-31N / mm 2 and / or, During the finishing rolling process, the conditions for cold rolling in one pass include: the entrance tension is 23-29N / mm 2 , outlet tension is 29-35N / mm 2 .

8. The method according to any one of claims 1 to 4 or 6, characterized in that: The method further comprises: before intermediate rolling, trimming the product obtained after rough rolling; and / or, The trimming conditions include: unwinding tension is 3710-3930N / mm 2 , the shear speed is 220-320m / min.

9. The method according to claim 1, characterized in that: The method further comprises: straightening the product obtained in step (5); and / or, The tensioning and straightening conditions include: unwinding tension of 23-29N / mm 2 , winding tension is 27-33N / mm 2 , elongation is 0.3-0.5%, speed is 290-350m / min.

10. The method according to claim 9, characterized in that The method further comprises: shearing the product obtained after tension and leveling; and / or, The shearing conditions include: shearing speed ≥ 300m / min, winding unit tension 20-25N / m 2 , the tension gradient is 95-105%, and the surface pressure value is 93-97N.

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