A forging deformation method for improving the comprehensive mechanical properties of 7050 aluminum alloy

Abstract

The present invention provides a forging deformation method for improving the comprehensive mechanical properties of 7050 aluminum alloy, comprising: heating the 7050 aluminum alloy ingot, performing the forging process of the first set of three upsetting and three drawing, then heating again, performing the forging process of the second set of three upsetting and three drawing, subsequently continuing to heat, and obtaining a blank after performing the forging process of the third set of three upsetting and three drawing; heating the blank obtained in the above step and then quenching it, and performing axial cold compression deformation to obtain a deformed blank; performing a four-stage aging heat treatment process on the deformed blank obtained above to obtain a forged blank. Through the forging and blooming process of nine upsetting and nine drawing, the present invention can improve the mechanical property uniformity of the overall material, refine the grains, give play to the performance advantages of the overall material, improve the comprehensive mechanical properties of 7050 aluminum alloy, thereby solving the problems of insufficient strength and elongation in the long transverse and short transverse directions existing in the existing 7050 products, and can also weld the original defects in the ingot and improve the flaw detection quality of the blank.

Description

Technical Field

[0001] The present invention belongs to the technical field of forging preparation of 7050 aluminum alloy rings, and relates to a forging deformation method of 7050 aluminum alloy, and particularly relates to a forging deformation method for improving the comprehensive mechanical properties of 7050 aluminum alloy. Background Art

[0002] 7050 alloy is widely used in the main load-bearing components in the aerospace field, such as the stiffening frames, load-bearing beams and joints of airplanes, the transition rings of rocket bodies, the end frames of engines, and the structural components of armed equipment. With the further improvement of the service requirements of the above-mentioned equipment, such as the reusability of the rocket body structure and zero-risk service, higher requirements are put forward for the performance of 7050 aluminum alloy. In existing research, the comprehensive performance is mainly provided by optimizing the alloy composition, improving the ingot metallurgical quality, multi-directional forging to refine the grains, and optimizing the ring rolling and heat treatment processes, such as:

[0003] CN201910428933.3 discloses a method for regulating the coarse second phase of 2219 aluminum alloy rings. By adopting seven upsetting and six drawing, combined with medium and low temperature ring rolling process, the coarse second phase of 2219 is effectively refined and the comprehensive performance is improved. However, this method is not suitable for the processing of 7xxx high alloy content.

[0004] CN202111534337.7 discloses a forging method of 7050 aluminum alloy forgings. By adopting four upsetting and four drawing forging, the grain structure is effectively refined and the comprehensive performance is improved. The performance of the forgings obtained by this method cannot meet the requirements of specific application scenarios.

[0005] CN202210837020.9 discloses a forging and heat treatment process of 7050 aluminum alloy large rings. By adopting three upsetting and three drawing forging, combined with multi-stage solution and aging processes, a method for 7050 aluminum alloy large rings is developed. The performance of the rings obtained by this method cannot meet the requirements of specific application scenarios.

[0006] In the existing disclosed methods, refining the grains by optimizing the forging method is an effective means to improve the comprehensive performance. However, due to the high content of 7050 alloy, the accumulation of forging deformation amount is likely to cause damage and defects such as cracks.

[0007] Therefore, developing a new deformation process that not only meets the requirement of further grain refinement but also meets the requirement of reducing forging deformation damage is an urgent problem to be solved for 7050 aluminum alloy at present and is also one of the urgent problems to be solved by many front-line researchers in the industry. Summary of the Invention

[0008] In view of this, the technical problem to be solved by the present invention is to provide a forging deformation method for 7050 aluminum alloy, especially a forging deformation method for improving the comprehensive mechanical properties of 7050 aluminum alloy. The nine-upsetting and nine-drawing forging blanking process provided by the present invention, supplemented by a four-stage aging heat treatment method, can improve the mechanical property uniformity of the material as a whole and give full play to the performance advantages of the material as a whole by refining the grains.

[0009] The present invention provides a forging deformation method for 7050 aluminum alloy, including the following steps:

[0010] (1) After heating the 7050 aluminum alloy ingot, perform the first set of three-upsetting and three-drawing forging processes, then heat it again, perform the second set of three-upsetting and three-drawing forging processes, and then continue to heat and perform the third set of three-upsetting and three-drawing forging processes to obtain a blank;

[0011] For the first set of three-upsetting and three-drawing forging processes, the upsetting ratio for the first upsetting is 55% - 60%; the height-diameter ratio for the first drawing is (2.4 - 2.6):1;

[0012] The upsetting ratio for the second upsetting is 50% - 55%; the height-diameter ratio for the second drawing is (2.3 - 2.5):1;

[0013] The upsetting ratio for the third upsetting is 45% - 50%; the height-diameter ratio for the third drawing is (2.2 - 2.4):1;

[0014] (2) Heat the blank obtained in the above step and then quench it, and perform axial cold compression deformation to obtain a deformed blank;

[0015] (3) After performing a four-stage aging heat treatment process on the deformed blank obtained above, obtain a forged blank.

[0016] Preferably, the heating temperature of the 7050 aluminum alloy ingot is 450 - 470 °C;

[0017] The heating time of the 7050 aluminum alloy ingot is 5 - 20 hours;

[0018] In the first set of three-upsetting and three-drawing forging processes, the forging speed is 1 - 5 mm / s.

[0019] Preferably, the re-heating time is 3 - 10 hours;

[0020] The re-heating temperature is 400 - 450 °C;

[0021] The continuous heating time is 4 - 15 hours;

[0022] The continuous heating temperature is 450 - 470 °C.

[0023] Preferably, in the forging process of the first group of three upsetting and three drawing operations, the deformation rate of the first upsetting is greater than that of the second upsetting;

[0024] In the forging process of the first group of three upsetting and three drawing operations, the deformation rate of the second upsetting is greater than that of the third upsetting;

[0025] In the forging process of the first group of three upsetting and three drawing operations, the height-diameter ratio of the first drawing is greater than that of the second drawing;

[0026] In the forging process of the first group of three upsetting and three drawing operations, the height-diameter ratio of the second drawing is greater than that of the third drawing.

[0027] Preferably, in the forging process of the second group of three upsetting and three drawing operations, the forging speed is 5 - 10 mm / s;

[0028] In the forging process of the second group of three upsetting and three drawing operations, the deformation rate of the first upsetting is 60% - 65%;

[0029] In the forging process of the second group of three upsetting and three drawing operations, the height-diameter ratio of the first drawing is (2.5 - 2.7):1;

[0030] In the forging process of the second group of three upsetting and three drawing operations, the deformation rate of the second upsetting is 55% - 60%;

[0031] In the forging process of the second group of three upsetting and three drawing operations, the height-diameter ratio of the second drawing is (2.4 - 2.6):1;

[0032] In the forging process of the second group of three upsetting and three drawing operations, the deformation rate of the third upsetting is 50% - 55%;

[0033] In the forging process of the second group of three upsetting and three drawing operations, the height-diameter ratio of the third drawing is (2.3 - 2.5):1.

[0034] Preferably, the deformation rate of the first upsetting in the forging process of the first group of three upsetting and three drawing operations is less than that of the first upsetting in the forging process of the second group of three upsetting and three drawing operations;

[0035] The height-diameter ratio of the first drawing in the forging process of the first group of three upsetting and three drawing operations is less than that of the first drawing in the forging process of the second group of three upsetting and three drawing operations;

[0036] In the forging process of the second group of three upsetting and three drawing operations, the deformation rate of the first upsetting is greater than that of the second upsetting;

[0037] In the forging process of the second group of three upsetting and three drawing operations, the deformation rate of the second upsetting is greater than that of the third upsetting;

[0038] In the forging process of the second group of three upsetting and three drawing operations, the height-diameter ratio of the first drawing is greater than that of the second drawing;

[0039] For the forging process of the second group of three upsetting and three drawing operations, the height-diameter ratio of the second drawing is greater than that of the third drawing.

[0040] Preferably, in the forging process of the third group of three upsetting and three drawing operations, the forging speed is 1 - 5 mm / s;

[0041] For the forging process of the third group of three upsetting and three drawing operations, the deformation rate of the first upsetting is 65% - 70%;

[0042] For the forging process of the third group of three upsetting and three drawing operations, the height-diameter ratio of the first drawing is (2.6 - 2.8):1;

[0043] For the forging process of the third group of three upsetting and three drawing operations, the deformation rate of the second upsetting is 60% - 65%;

[0044] For the forging process of the third group of three upsetting and three drawing operations, the height-diameter ratio of the second drawing is (2.5 - 2.7):1;

[0045] For the forging process of the third group of three upsetting and three drawing operations, the deformation rate of the third upsetting is 55% - 60%;

[0046] For the forging process of the third group of three upsetting and three drawing operations, the height-diameter ratio of the third drawing is (2.4 - 2.6):1.

[0047] Preferably, the deformation rate of the first upsetting in the forging process of the second group of three upsetting and three drawing operations is less than that of the first upsetting in the forging process of the third group of three upsetting and three drawing operations;

[0048] The height-diameter ratio of the first drawing in the forging process of the second group of three upsetting and three drawing operations is less than that of the first drawing in the forging process of the third group of three upsetting and three drawing operations;

[0049] For the forging process of the third group of three upsetting and three drawing operations, the deformation rate of the first upsetting is greater than that of the second upsetting;

[0050] For the forging process of the third group of three upsetting and three drawing operations, the deformation rate of the second upsetting is greater than that of the third upsetting;

[0051] For the forging process of the third group of three upsetting and three drawing operations, the height-diameter ratio of the first drawing is greater than that of the second drawing;

[0052] For the forging process of the third group of three upsetting and three drawing operations, the height-diameter ratio of the second drawing is greater than that of the third drawing.

[0053] Preferably, the 7050 aluminum alloy includes a 7050 aluminum alloy ring;

[0054] After the step (1), one or more steps of punching, reaming and ring rolling on the blank are further included;

[0055] The wall thickness deformation rate of the reaming accounts for 70% - 90% of the total wall thickness deformation rate of the reaming and ring rolling;

[0056] The heating temperature in the step (2) is 470 - 480 °C;

[0057] The heating time in the step (2) is 120 - 570 min;

[0058] The quenching method includes water quenching;

[0059] The interval time between the axial cold compression deformation and quenching is less than or equal to 3 hours;

[0060] The cold deformation rate of the axial cold compression deformation is less than or equal to 5%.

[0061] Preferably, in the four - stage aging heat treatment, the temperature of the first - stage aging heat treatment is 100 - 130 °C;

[0062] In the four - stage aging heat treatment, the holding time of the first - stage aging heat treatment is 8 - 12 h;

[0063] In the four - stage aging heat treatment, the temperature of the second - stage aging heat treatment is 135 - 145 °C;

[0064] In the four - stage aging heat treatment, the holding time of the second - stage aging heat treatment is 2 - 3 h;

[0065] In the four - stage aging heat treatment, the temperature of the third - stage aging heat treatment is 155 - 165 °C;

[0066] In the four - stage aging heat treatment, the holding time of the third - stage aging heat treatment is 1 - 2 h;

[0067] In the four - stage aging heat treatment, the temperature of the fourth - stage aging heat treatment is 174 - 180 °C;

[0068] In the four - stage aging heat treatment, the holding time of the fourth - stage aging heat treatment is 4 - 6 h.

[0069] Beneficial effects: The present invention provides a forging deformation method for 7050 aluminum alloy, which includes the following steps. First, heat the 7050 aluminum alloy ingot, and then perform the forging process of three upsetting and three drawing in the first group. Then heat it again and perform the forging process of three upsetting and three drawing in the second group. Subsequently, continue heating and perform the forging process of three upsetting and three drawing in the third group to obtain a blank. Then heat the blank obtained in the above steps and quench it, and perform axial cold compression deformation to obtain a deformed blank. Finally, perform a four-stage aging heat treatment process on the deformed blank obtained above to obtain a forged blank. Compared with the prior art, the present invention proposes an ingot blooming deformation method based on multi-pass multi-direction forging to improve the comprehensive mechanical properties of 7050 aluminum alloy. The present invention refines the grains of the blank through a nine-upsetting and nine-drawing forging blooming process, that is, first perform three upsetting and three drawing deformations at high temperature and low speed to fully improve the plasticity of the ingot, then perform three upsetting and three drawing deformations at medium temperature and high speed to fully deform and refine the grains, and finally perform three upsetting and three drawing deformations at high temperature and low speed to inhibit damage and further refine the grains. By returning the blank to the heating furnace for heat preservation between every two times to maintain the internal temperature of the blank and restore plasticity, and further through the specific upsetting and drawing ratio within a single group of upsetting and drawing and the parameter correlation between each group of upsetting and drawing, and supplemented by a four-stage aging heat treatment process, the temperature uniformity during aging is improved, and while improving the overall mechanical properties of the material, the uniformity is also taken into account.

[0070] The nine-upsetting and nine-drawing forging blooming process provided by the present invention can improve the overall mechanical property uniformity of the material, and exert the performance advantages of the overall material by refining the grains, thus solving the problems of insufficient strength and elongation in the long transverse and short transverse directions existing in existing 7050 products, and can improve the mechanical properties and property uniformity of the product as a whole, and can also weld the original defects in the ingot and improve the flaw detection quality of the blank.

[0071] Experimental results show that the grain structure of the 7050 forgings of the present invention is fine and uniform, and the comprehensive mechanical properties are high. Especially, the elongation in the long transverse and short transverse directions reaches more than 6%, which is higher than the existing conventional process, and can meet the high-performance requirements of specific application scenarios. Description of the Drawings

[0072] Figure 1 It is the metallographic picture of the forged blank prepared in Example 1 of the present invention;

[0073] Figure 2 It is the metallographic picture of the forged blank prepared in Comparative Example 1 of the present invention;

[0074] Figure 3 It is the metallographic picture of the forged blank prepared in Comparative Example 2 of the present invention. Detailed Embodiments

[0075] To further understand the present invention, the preferred embodiments of the present invention will be described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention.

[0076] For all raw materials of the present invention, there are no special restrictions on their sources, and they can be purchased on the market or prepared by conventional methods well-known to those skilled in the art.

[0077] For all raw materials of the present invention, there are no special restrictions on their purity. The present invention preferably uses industrial purity or the conventional purity requirements in the field of preparing 7050 series aluminum alloys.

[0078] For all raw materials of the present invention, their grades and abbreviations are all conventional grades and abbreviations in the art. Each grade and abbreviation is clear and definite in the field of its relevant uses. Those skilled in the art can obtain them from the market or prepare them by conventional methods according to the grade, abbreviation and corresponding uses.

[0079] For the processes used in the present invention, their abbreviations are all conventional abbreviations in the art. The specific steps and conventional parameters of each abbreviation are clear and definite in their relevant fields. Those skilled in the art can implement them by conventional methods according to the abbreviations.

[0080] Anisotropy: The property that the properties of a material vary in different directions. Since the overall improvement of the material properties is limited, generally, reducing the anisotropy of the material properties helps to meet the usage requirements of the buyer.

[0081] Isotropy: The property that the properties of a material are the same or similar in different directions, that is, uniformity, which is the opposite of anisotropy.

[0082] Refining grains: Making the crystal size in the material smaller and the number more. This effect can improve both the strength and elongation of the material.

[0083] Upsetting deformation rate: The percentage of the height difference before and after upsetting to the height before upsetting.

[0084] Height-diameter ratio: The ratio of the height of the billet to the diameter. To make the upsetting deformation more uniform and effective, it is necessary to control the billet to reach a certain height-diameter ratio during drawing out.

[0085] Performance directions: Longitudinal, long transverse, short transverse, generally representing the directions from the best to the worst mechanical properties of the material respectively.

[0086] Shape directions: For ring parts, they are circumferential, radial and axial respectively. When the properties of the ring part are determined, the shape directions can correspond to the performance directions.

[0087] The present invention provides a forging deformation method for 7050 aluminum alloy, comprising the following steps:

[0088] (1)After heating the 7050 aluminum alloy ingot, perform the forging process of three upsetting and three drawing in the first group, then heat it again, perform the forging process of three upsetting and three drawing in the second group, and then continue to heat it, and obtain a blank after performing the forging process of three upsetting and three drawing in the third group;

[0089] For the forging process of three upsetting and three drawing in the first group, the upsetting deformation rate for the first time is 55% - 60%; the height-diameter ratio for the first drawing is (2.4 - 2.6):1;

[0090] The upsetting deformation rate for the second time is 50% - 55%; the height-diameter ratio for the second drawing is (2.3 - 2.5):1;

[0091] The upsetting deformation rate for the third time is 45% - 50%; the height-diameter ratio for the third drawing is (2.2 - 2.4):1;

[0092] (2)After heating the blank obtained in the above step, perform quenching and axial cold compression deformation to obtain a deformed blank;

[0093] (3)After performing a four-stage aging heat treatment process on the deformed blank obtained above, obtain a forged blank.

[0094] In the present invention, first heat the 7050 aluminum alloy ingot, perform the forging process of three upsetting and three drawing in the first group, then heat it again, perform the forging process of three upsetting and three drawing in the second group, and then continue to heat it, and obtain a blank after performing the forging process of three upsetting and three drawing in the third group.

[0095] In the present invention, the heating temperature of the 7050 aluminum alloy ingot is preferably 450 - 470 °C, more preferably 455 - 465 °C, and even more preferably 458 - 462 °C.

[0096] In the present invention, the heating time of the 7050 aluminum alloy ingot is preferably 5 - 20 hours, more preferably 8 - 17 hours, and even more preferably 11 - 14 hours.

[0097] In the present invention, in the forging process of three upsetting and three drawing in the first group, the forging speed is preferably 1 - 5 mm / s, more preferably 2 - 4 mm / s, and even more preferably 2.2 - 3.6 mm / s.

[0098] In the present invention, for the forging process of three upsetting and three drawing in the first group, the upsetting deformation rate for the first time is preferably 55% - 60%, more preferably 56% - 59%, and even more preferably 57% - 58%.

[0099] In the present invention, for the forging process of three upsetting and three drawing in the first group, the height-diameter ratio for the first drawing is preferably (2.4 - 2.6):1, more preferably (2.44 - 2.56):1, and even more preferably (2.48 - 2.52):1.

[0100] In the present invention, for the forging process of the first group of three upsetting and three drawing operations, the deformation rate of the second upsetting is preferably 50% - 55%, more preferably 51% - 54%, and even more preferably 52% - 53%.

[0101] In the present invention, for the forging process of the first group of three upsetting and three drawing operations, the height - to - diameter ratio of the second drawing is preferably (2.3 - 2.5):1, more preferably (2.34 - 2.46):1, and even more preferably (2.38 - 2.42):1.

[0102] In the present invention, for the forging process of the first group of three upsetting and three drawing operations, the deformation rate of the third upsetting is preferably 45% - 50%, more preferably 46% - 49%, and even more preferably 47% - 48%.

[0103] In the present invention, for the forging process of the first group of three upsetting and three drawing operations, the height - to - diameter ratio of the third drawing is preferably (2.2 - 2.4):1, more preferably (2.24 - 2.36):1, and even more preferably (2.28 - 2.32):1.

[0104] In the present invention, the time for the re - heating is preferably 3 - 10 hours, more preferably 4 - 9 hours, even more preferably 5 - 8 hours, and still more preferably 6 - 7 hours.

[0105] In the present invention, the temperature for the re - heating is preferably 400 - 450 °C, more preferably 420 - 440 °C, and even more preferably 428 - 438 °C.

[0106] In the present invention, for the forging process of the first group of three upsetting and three drawing operations, the deformation rate of the first upsetting is preferably greater than that of the second upsetting;

[0107] In the present invention, for the forging process of the first group of three upsetting and three drawing operations, the deformation rate of the second upsetting is preferably greater than that of the third upsetting;

[0108] In the present invention, for the forging process of the first group of three upsetting and three drawing operations, the height - to - diameter ratio of the first drawing is preferably greater than that of the second drawing;

[0109] In the present invention, for the forging process of the first group of three upsetting and three drawing operations, the height - to - diameter ratio of the second drawing is preferably greater than that of the third drawing.

[0110] In the present invention, in the forging process of the second group of three upsetting and three drawing operations, the forging speed is preferably 5 - 10 mm / s, more preferably 6 - 9 mm / s, and even more preferably 7.2 - 8.6 mm / s.

[0111] In the present invention, for the forging process of the second group of three upsetting and three drawing processes, the deformation rate of the first upsetting is preferably 60% - 65%, more preferably 61% - 64%, and even more preferably 62% - 63%.

[0112] In the present invention, for the forging process of the second group of three upsetting and three drawing processes, the height - to - diameter ratio of the first drawing is preferably (2.5 - 2.7):1, more preferably (2.54 - 2.66):1, and even more preferably (2.58 - 2.62):1.

[0113] In the present invention, for the forging process of the second group of three upsetting and three drawing processes, the deformation rate of the second upsetting is preferably 55% - 60%, more preferably 56% - 59%, and even more preferably 57% - 58%.

[0114] In the present invention, for the forging process of the second group of three upsetting and three drawing processes, the height - to - diameter ratio of the second drawing is preferably (2.4 - 2.6):1, more preferably (2.44 - 2.56):1, and even more preferably (2.48 - 2.52):1.

[0115] In the present invention, for the forging process of the second group of three upsetting and three drawing processes, the deformation rate of the third upsetting is preferably 50% - 55%, more preferably 51% - 54%, and even more preferably 52% - 53%.

[0116] In the present invention, for the forging process of the second group of three upsetting and three drawing processes, the height - to - diameter ratio of the third drawing is preferably (2.3 - 2.5):1, more preferably (2.34 - 2.46):1, and even more preferably (2.38 - 2.42):1.

[0117] In the present invention, the time for the continued heating is preferably 4 - 15 hours, more preferably 6 - 13 hours, and even more preferably 8 - 11 hours.

[0118] In the present invention, the temperature for the continued heating is preferably 450 - 470 °C, more preferably 455 - 465 °C, and even more preferably 458 - 462 °C.

[0119] In the present invention, the deformation rate of the first upsetting in the forging process of the first group of three upsetting and three drawing processes is preferably less than the deformation rate of the first upsetting in the forging process of the second group of three upsetting and three drawing processes.

[0120] In the present invention, the height - to - diameter ratio of the first drawing in the forging process of the first group of three upsetting and three drawing processes is preferably less than the height - to - diameter ratio of the first drawing in the forging process of the second group of three upsetting and three drawing processes.

[0121] In the present invention, for the forging process of the second group of three upsetting and three drawing processes, the deformation rate of the first upsetting is preferably greater than the deformation rate of the second upsetting.

[0122] In the present invention, in the forging process of the second group of three upsetting and three drawing, the deformation rate of the second upsetting is greater than that of the third upsetting.

[0123] In the present invention, in the forging process of the second group of three upsetting and three drawing, the height-diameter ratio of the first drawing is preferably greater than that of the second drawing.

[0124] In the present invention, in the forging process of the second group of three upsetting and three drawing, the height-diameter ratio of the second drawing is preferably greater than that of the third drawing.

[0125] In the present invention, in the forging process of the third group of three upsetting and three drawing, the forging speed is preferably 1 - 5 mm / s, more preferably 2 - 4 mm / s, and even more preferably 2.2 - 3.6 mm / s.

[0126] In the present invention, in the forging process of the third group of three upsetting and three drawing, the deformation rate of the first upsetting is preferably 65% - 70%, more preferably 66% - 69%, and even more preferably 67% - 68%.

[0127] In the present invention, in the forging process of the third group of three upsetting and three drawing, the height-diameter ratio of the first drawing is preferably (2.6 - 2.8):1, more preferably (2.64 - 2.76):1, and even more preferably (2.68 - 2.72):1.

[0128] In the present invention, in the forging process of the third group of three upsetting and three drawing, the deformation rate of the second upsetting is preferably 60% - 65%, more preferably 61% - 64%, and even more preferably 62% - 63%.

[0129] In the present invention, in the forging process of the third group of three upsetting and three drawing, the height-diameter ratio of the second drawing is preferably (2.5 - 2.7):1, more preferably (2.54 - 2.66):1, and even more preferably (2.58 - 2.62):1.

[0130] In the present invention, in the forging process of the third group of three upsetting and three drawing, the deformation rate of the third upsetting is preferably 55% - 60%, more preferably 56% - 59%, and even more preferably 57% - 58%.

[0131] In the present invention, in the forging process of the third group of three upsetting and three drawing, the height-diameter ratio of the third drawing is preferably (2.4 - 2.6):1, more preferably (2.44 - 2.56):1, and even more preferably (2.48 - 2.52):1.

[0132] In the present invention, the deformation rate of the first upsetting in the forging process of the second group of three upsetting and three drawing is preferably less than that of the first upsetting in the forging process of the third group of three upsetting and three drawing.

[0133] In the present invention, the aspect ratio of the first drawing in the forging process of the second group of three-upsetting-and-three-drawing is preferably less than that of the first drawing in the forging process of the third group of three-upsetting-and-three-drawing.

[0134] In the present invention, in the forging process of the third group of three-upsetting-and-three-drawing, the deformation rate of the first upsetting is preferably greater than that of the second upsetting.

[0135] In the present invention, in the forging process of the third group of three-upsetting-and-three-drawing, the deformation rate of the second upsetting is preferably greater than that of the third upsetting.

[0136] In the present invention, in the forging process of the third group of three-upsetting-and-three-drawing, the aspect ratio of the first drawing is preferably greater than that of the second drawing.

[0137] In the present invention, in the forging process of the third group of three-upsetting-and-three-drawing, the aspect ratio of the second drawing is preferably greater than that of the third drawing.

[0138] Specifically, the specific parameters of the three groups of three-upsetting-and-three-drawing forging processes are shown in Table 1:

[0139] Table 1

[0140]

[0141] In the present invention, the 7050 aluminum alloy preferably includes a 7050 aluminum alloy ring.

[0142] In the present invention, the component content of the 7050 aluminum alloy can be specifically shown in Table 2:

[0143] Table 2

[0144]

[0145] In the present invention, after the step (1), it preferably further includes one or more of the steps of punching, reaming, and ring rolling the blank, and more preferably includes multiple steps of punching, reaming, and ring rolling the blank.

[0146] In the present invention, the wall thickness deformation rate of the reaming preferably accounts for 70% - 90% of the total wall thickness deformation rate of the reaming and ring rolling, more preferably 74% - 86%, and more preferably 78% - 82%.

[0147] The present invention then heats the blank obtained in the above steps and quenches it, and performs axial cold compression deformation to obtain a deformed blank.

[0148] In the present invention, the heating temperature in the step (2) is preferably 470 - 480 °C, more preferably 472 - 478 °C, and more preferably 474 - 476 °C.

[0149] In the present invention, the heating time in the step (2) is preferably 120 to 570 min, more preferably 200 to 500 min, and even more preferably 300 to 400 min.

[0150] In the present invention, the quenching method preferably includes water quenching.

[0151] In the present invention, the time interval between the axial cold compression deformation and quenching is preferably less than or equal to 3 hours, more preferably less than or equal to 2 hours, and even more preferably less than or equal to 1 hour.

[0152] In the present invention, the cold deformation rate of the axial cold compression deformation is preferably less than or equal to 5%, more preferably less than or equal to 4%, and even more preferably less than or equal to 3%.

[0153] Finally, the deformed blank is subjected to a four-stage aging heat treatment process in the present invention to obtain a forging blank.

[0154] In the present invention, in the four-stage aging heat treatment, the temperature of the first-stage aging heat treatment is preferably 100 to 130 °C, more preferably 105 to 125 °C, and even more preferably 110 to 120 °C.

[0155] In the present invention, in the four-stage aging heat treatment, the holding time of the first-stage aging heat treatment is preferably 8 to 12 h, more preferably 8.5 to 11.5 h, even more preferably 9 to 11 h, and even more preferably 9.5 to 10.5 h.

[0156] In the present invention, in the four-stage aging heat treatment, the temperature of the second-stage aging heat treatment is preferably 135 to 145 °C, more preferably 137 to 143 °C, and even more preferably 139 to 141 °C.

[0157] In the present invention, in the four-stage aging heat treatment, the holding time of the second-stage aging heat treatment is preferably 2 to 3 h, more preferably 2.2 to 2.8 h, and even more preferably 2.4 to 2.6 h.

[0158] In the present invention, in the four-stage aging heat treatment, the temperature of the third-stage aging heat treatment is preferably 155 to 165 °C, more preferably 157 to 163 °C, and even more preferably 159 to 161 °C.

[0159] In the present invention, in the four-stage aging heat treatment, the holding time of the third-stage aging heat treatment is preferably 1 to 2 h, more preferably 1.2 to 1.8 h, and even more preferably 1.4 to 1.6 h.

[0160] In the present invention, in the four-stage aging heat treatment, the temperature of the fourth-stage aging heat treatment is preferably 174 to 180 °C, more preferably 175 to 179 °C, and even more preferably 176 to 178 °C.

[0161] In the present invention, in the four-stage aging heat treatment, the holding time of the fourth-stage aging heat treatment is preferably 4 to 6 h, more preferably 4.4 to 5.6 h, and even more preferably 4.8 to 5.2 h.

[0162] To complete and refine the overall technical solution of the present invention, and to better improve the mechanical property uniformity of the overall 7050 aluminum alloy material, and further to exert the overall performance advantages of the material by refining the grains, the forging deformation method for improving the comprehensive mechanical properties of 7050 aluminum alloy preferably includes the following steps:

[0163] The present invention refines the grains of the billet through a forging and blooming process of nine upsetting and nine drawing, and supplements it with a heat treatment process of four-stage aging to improve the temperature uniformity during the aging process, taking into account both the overall mechanical properties and the uniformity of the material.

[0164] Specific technical solution (taking the 7050T7652 ring as an example):

[0165] The first step: heating the ingot at 450 - 470 °C;

[0166] The second step: performing a forging process of three upsetting and three drawing on the ingot, then returning it to the furnace for heating at the original temperature, and completing three times of three upsetting and three drawing processes in this order;

[0167] The third step: punching the billet, then expanding the hole and ring rolling to a certain size;

[0168] The fourth step: heating the billet to 470 - 480 °C and then quenching it, followed by axial cold compression deformation;

[0169] The fifth step: performing four-stage aging heat treatment on the billet within the range of 100 - 180 °C.

[0170] Specifically, in the second step, the upsetting deformation rate is controlled at 45% - 70%, the height-diameter ratio of the billet after drawing is controlled at 2.2 - 2.8, and the upsetting deformation rate of the last time does not exceed 60%.

[0171] Specifically, in the second step, the heating time between every two times of three upsetting and three drawing processes is not less than 3 hours to ensure the temperature recovery and damage repair of the billet.

[0172] Specifically, in the third step, the hole expanding and ring rolling processes are combined to expand the size of the ring, and the main deformation is hole expanding, and the wall thickness deformation rate accounts for more than 70%.

[0173] Specifically, in the fourth step, the axial cold compression needs to be completed within 3 h after the ring is quenched, and the cold deformation rate does not exceed 5%.

[0174] Specifically, the four-stage aging heat treatment can be carried out for aging heating in four temperature sections of 121 °C, 140 °C, 160 °C, and 177 °C.

[0175] Specifically, in the fifth step, the holding time at 121°C is 8 - 12 h, the holding time at 140°C is 2 - 3 h, the holding time at 160°C is 1 - 2 h, and the holding time at 177°C is 4 - 6 h. The holding times at 140°C and 160°C should not be too long as they are only transition temperature segments to ensure uniform temperature inside the blank.

[0176] The cogging process of nine upsetting and nine drawing in the present invention can also be replaced by other cogging methods with more upsetting and drawing passes, such as ten upsetting and ten drawing, etc. Use more multi-stage aging heat treatment schemes to replace the four-stage aging scheme. Using products of other alloy grades, states, and specifications can also obtain similar technical effects.

[0177] The above content of the present invention provides a forging deformation method for improving the comprehensive mechanical properties of 7050 aluminum alloy. Taking 7050 aluminum alloy as an example, the ingot cogging deformation method based on multi-pass multi-directional forging proposed by the present invention is used to improve the comprehensive mechanical properties of 7050 aluminum alloy. The present invention refines the blank grains through the forging cogging process of nine upsetting and nine drawing, that is, first deforming with three upsetting and three drawing at high temperature and low speed to fully improve the plasticity of the ingot, then deforming with three upsetting and three drawing at medium temperature and high speed to fully deform and refine the grains, and finally deforming with three upsetting and three drawing at high temperature and low speed to inhibit damage and further refine the grains. Between each two times, the blank is returned to the heating furnace for heat preservation to maintain the internal temperature of the blank and restore plasticity. Further, through the specific upsetting and drawing ratios within a single upsetting and drawing and the parameter correlation between each group of upsetting and drawing, and supplemented by a four-stage aging heat treatment process, the temperature uniformity during aging is improved, taking into account both the overall mechanical properties and the uniformity of the material.

[0178] To further illustrate the present invention, the following describes in detail a forging deformation method of 7050 aluminum alloy provided by the present invention in combination with embodiments. However, it should be understood that these embodiments are implemented on the premise of the technical solution of the present invention, giving detailed implementation manners and specific operation processes, only to further illustrate the features and advantages of the present invention, rather than a limitation on the claims of the present invention. The protection scope of the present invention is not limited to the following embodiments.

[0179] Example 1

[0180] The first step: Heat the ingot to 460°C and hold for 12 h.

[0181] The second step: Perform the forging process of three upsetting and three drawing on the ingot, with a forging speed of 3 mm / s. The first upsetting is 57%, the height-diameter ratio of the first drawing is 2.5:1, the deformation rate of the second upsetting is preferably 52%, the height-diameter ratio of the second drawing is 2.4:1, the deformation rate of the third upsetting is 47%, and the height-diameter ratio of the third drawing is 2.3:1.

[0182] Step 3: Subsequently, return it to the furnace for heating. The heating temperature is 430°C and the holding time is 6 h;

[0183] Step 4: Perform a forging process of three upsetting and three drawing on the above blank. The forging speed is 8 mm / s. The deformation rate of the first upsetting is 62%, the height-diameter ratio of the first drawing is 2.6:1, the deformation rate of the second upsetting is 58%, the height-diameter ratio of the second drawing is 2.5:1, the deformation rate of the third upsetting is 52%, and the height-diameter ratio of the third drawing is 2.4:1.

[0184] Step 5: Subsequently, return it to the furnace for heating. The heating temperature is 460°C and the holding time is 10 h;

[0185] Step 6: Perform a forging process of three upsetting and three drawing on the above blank. The forging speed is 3 mm / s. The deformation rate of the first upsetting is 68%, the height-diameter ratio of the first drawing is 2.7:1, the deformation rate of the second upsetting is 62%, the height-diameter ratio of the second drawing is 2.6:1, the deformation rate of the third upsetting is 52%, and the height-diameter ratio of the third drawing is 2.5:1.

[0186] Step 7: Punch the blank, and then expand the hole and roll ring it to a certain size;

[0187] Step 8: Heat the blank to 475°C, quench it after holding for 350 min, and then perform axial cold compression deformation with a deformation amount of 3%;

[0188] Step 9: Heat the blank to 120°C, hold for 10 h, continue to heat to 140°C, hold for 2.5 h, then heat to 160°C, hold for 1.5 h, and finally heat to 177°C, hold for 5 h.

[0189] See Figure 1 , Figure 1 which is the metallographic picture of the forged blank prepared in Example 1 of the present invention.

[0190] Comparative Example 1

[0191] Step 1: Heat the ingot at 460°C with a holding time of 12 h;

[0192] Step 2: Perform a forging process of three upsetting and three drawing on the ingot. The forging speed is 3 mm / s. The first time is 57%, the height-diameter ratio of the first drawing is 2.5:1. The deformation rate of the second upsetting is preferably 52%, the height-diameter ratio of the second drawing is 2.4:1, the deformation rate of the third upsetting is 47%, and the height-diameter ratio of the third drawing is 2.3:1.

[0193] Step 3: Subsequently, return it to the furnace for heating. The heating temperature is 430°C and the holding time is 6 h;

[0194] Step 4: Subject the above blank to a forging process of three upsetting and three drawing operations, with a forging speed of 8 mm / s, a deformation rate of 62% for the first upsetting, a height-to-diameter ratio of 2.6:1 for the first drawing, a deformation rate of 58% for the second upsetting, a height-to-diameter ratio of 2.5:1 for the second drawing, a deformation rate of 52% for the third upsetting, and a height-to-diameter ratio of 2.4:1 for the third drawing.

[0195] Step 5: Punch the blank, and then ream and ring roll it to a certain size;

[0196] Step 6: Heat the blank to 475 °C, quench it after holding for 350 min, and then perform axial cold compression deformation with a deformation amount of 3%;

[0197] Step 7: Heat the blank to 120 °C, hold for 10 h, continue to heat to 140 °C, hold for 2.5 h, then heat to 160 °C, hold for 1.5 h, and finally heat to 177 °C, hold for 5 h.

[0198] See Figure 2 , Figure 2 which is the metallographic picture of the forged blank prepared in Comparative Example 1 of the present invention.

[0199] Comparative Example 2

[0200] Step 1: Heat the ingot to 460 °C and hold for 12 h;

[0201] Step 2: Subject the ingot to a forging process of three upsetting and three drawing operations, with a forging speed of 3 mm / s, a deformation rate of 57% for the first upsetting, a height-to-diameter ratio of 2.5:1 for the first drawing, a preferably deformation rate of 52% for the second upsetting, a height-to-diameter ratio of 2.4:1 for the second drawing, a deformation rate of 47% for the third upsetting, and a height-to-diameter ratio of 2.3:1 for the third drawing.

[0202] Step 3: Then return it to the furnace for heating at a heating temperature of 430 °C and hold for 6 h;

[0203] Step 4: Subject the above blank to a forging process of three upsetting and three drawing operations, with a forging speed of 8 mm / s, a deformation rate of 62% for the first upsetting, a height-to-diameter ratio of 2.6:1 for the first drawing, a deformation rate of 58% for the second upsetting, a height-to-diameter ratio of 2.5:1 for the second drawing, a deformation rate of 52% for the third upsetting, and a height-to-diameter ratio of 2.4:1 for the third drawing.

[0204] Step 5: Heat the blank to 120 °C, hold for 10 h, continue to heat to 140 °C, hold for 2.5 h, then heat to 160 °C, hold for 1.5 h, and finally heat to 177 °C, hold for 5 h.

[0205] See Figure 3 , Figure 3Metallographic picture of the forging blank prepared in Comparative Example 2 of the present invention.

[0206] Refer to Table 3. Table 3 shows the performance data of the 7050 aluminum alloy forging blanks prepared in the examples and comparative examples of the present invention.

[0207] Table 3

[0208]

[0209] The above has introduced in detail a forging deformation method for improving the comprehensive mechanical properties of 7050 aluminum alloy provided by the present invention. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above examples is only used to help understand the method and its core idea of the present invention, including the best mode, and also enables any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The protection scope of the present invention patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the literal description of the claims, or if they include equivalent structural elements that have no substantial difference from the literal description of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A forging deformation method for improving the comprehensive mechanical properties of 7050 aluminum alloy, characterized in that, It includes the following steps: (1) After heating the 7050 aluminum alloy ingot, perform the forging process of three upsetting and three drawing in the first group, then heat it again, perform the forging process of three upsetting and three drawing in the second group, and then continue to heat and perform the forging process of three upsetting and three drawing in the third group to obtain a blank; The heating temperature of the 7050 aluminum alloy ingot is 450 - 470 °C; In the forging process of the first group of three upsetting and three drawing, the forging speed is 1 - 5 mm / s; The temperature of the re-heating is 400 - 450 °C; In the forging process of the second group of three upsetting and three drawing, the forging speed is 5 - 10 mm / s; The temperature of the continued heating is 450 - 470 °C; In the forging process of the third group of three upsetting and three drawing, the forging speed is 1 - 5 mm / s; (2) Heat the blank obtained in the above step and then quench it, and perform axial cold compression deformation to obtain a deformed blank; (3) After performing a four-stage aging heat treatment process on the deformed blank obtained above, obtain a forged blank.

2. The forging deformation method according to claim 1, characterized in that The heating time of the 7050 aluminum alloy ingot is 5 - 20 hours; In the forging process of the first group of three upsetting and three drawing, the upsetting deformation rate of the first upsetting is 55% - 60%; the height-diameter ratio of the first drawing is (2.4 - 2.6):1; The upsetting deformation rate of the second upsetting is 50% - 55%; the height-diameter ratio of the second drawing is (2.3 - 2.5):1; The upsetting deformation rate of the third upsetting is 45% - 50%; the height-diameter ratio of the third drawing is (2.2 - 2.4):

1.

3. The forging deformation method according to claim 1, characterized in that The re-heating time is 3 - 10 hours; The continued heating time is 4 - 15 hours.

4. The forging deformation method according to claim 1, characterized in that, In the forging process of the first group of three upsetting and three drawing, the upsetting deformation rate of the first upsetting is greater than that of the second upsetting; In the forging process of the first group of three upsetting and three drawing, the upsetting deformation rate of the second upsetting is greater than that of the third upsetting; In the forging process of the first group of three upsetting and three drawing, the height-diameter ratio of the first drawing is greater than that of the second drawing; In the forging process of the first group of three upsetting and three drawing, the height-diameter ratio of the second drawing is greater than that of the third drawing.

5. The forging deformation method according to claim 1, wherein In the forging process of the second group of three upsetting and three drawing, the upsetting deformation rate of the first upsetting is 60% - 65%; In the forging process of the second group of three upsetting and three drawing, the height-diameter ratio of the first drawing is (2.5 - 2.7):1; In the forging process of the second group of three upsetting and three drawing, the upsetting deformation rate of the second upsetting is 55% - 60%; In the forging process of the second group of three upsetting and three drawing, the height-diameter ratio of the second drawing is (2.4 - 2.6):1; In the forging process of the second group of three upsetting and three drawing, the upsetting deformation rate of the third upsetting is 50% - 55%; In the forging process of the second group of three upsetting and three drawing, the height-diameter ratio of the third drawing is (2.3 - 2.5):

1.

6. The forging deformation method according to claim 1, wherein The upsetting deformation rate of the first upsetting in the forging process of the first group of three upsetting and three drawing is less than that of the first upsetting in the forging process of the second group of three upsetting and three drawing; The height-diameter ratio of the first drawing in the forging process of the first group of three upsetting and three drawing is less than that of the first drawing in the forging process of the second group of three upsetting and three drawing; In the forging process of the second group of three upsetting and three drawing, the upsetting deformation rate of the first upsetting is greater than that of the second upsetting; For the forging process of the second group of three upsetting and three drawing, the deformation rate of the second upsetting is greater than that of the third upsetting; For the forging process of the second group of three upsetting and three drawing, the height-diameter ratio of the first drawing is greater than that of the second drawing; For the forging process of the second group of three upsetting and three drawing, the height-diameter ratio of the second drawing is greater than that of the third drawing.

7. The forging deformation method according to claim 1, characterized in that For the forging process of the third group of three upsetting and three drawing, the deformation rate of the first upsetting is 65% - 70%; For the forging process of the third group of three upsetting and three drawing, the height-diameter ratio of the first drawing is (2.6 - 2.8):1; For the forging process of the third group of three upsetting and three drawing, the deformation rate of the second upsetting is 60% - 65%; For the forging process of the third group of three upsetting and three drawing, the height-diameter ratio of the second drawing is (2.5 - 2.7):1; For the forging process of the third group of three upsetting and three drawing, the deformation rate of the third upsetting is 55% - 60%; For the forging process of the third group of three upsetting and three drawing, the height-diameter ratio of the third drawing is (2.4 - 2.6):

1.

8. The forging deformation method according to claim 1, characterized in that The deformation rate of the first upsetting in the forging process of the second group of three upsetting and three drawing is less than that of the first upsetting in the forging process of the third group of three upsetting and three drawing; The height-diameter ratio of the first drawing in the forging process of the second group of three upsetting and three drawing is less than that of the first drawing in the forging process of the third group of three upsetting and three drawing; For the forging process of the third group of three upsetting and three drawing, the deformation rate of the first upsetting is greater than that of the second upsetting; For the forging process of the third group of three upsetting and three drawing, the deformation rate of the second upsetting is greater than that of the third upsetting; For the forging process of the third group of three upsetting and three drawing, the height-diameter ratio of the first drawing is greater than that of the second drawing; For the forging process of the third group of three upsetting and three drawing, the height-diameter ratio of the second drawing is greater than that of the third drawing.

9. The forging deformation method according to claim 1, characterized in that The 7050 aluminum alloy includes a 7050 aluminum alloy ring; After the step (1), it further includes one or more steps of punching, hole expanding, and ring rolling on the blank; The wall thickness deformation rate of the hole expanding accounts for 70% - 90% of the total wall thickness deformation rate of the hole expanding and ring rolling; The heating temperature in the step (2) is 470 - 480 °C; The heating time in the step (2) is 120 - 570 min; The quenching method includes water quenching; The time interval between the axial cold compression deformation and quenching is less than or equal to 3 hours; The cold deformation rate of the axial cold compression deformation is less than or equal to 5%.

10. The forging deformation method according to claim 1, characterized in that, [[ID=2V]]In the four-stage aging heat treatment, the temperature of the first-stage aging heat treatment is 100 - 130 °C; In the four-stage aging heat treatment, the holding time of the first-stage aging heat treatment is 8 - 12 h; In the four-stage aging heat treatment, the temperature of the second-stage aging heat treatment is 135 - 145 °C; In the four-stage aging heat treatment, the holding time of the second-stage aging heat treatment is 2 - 3 h; In the four-stage aging heat treatment, the temperature of the third-stage aging heat treatment is 155 - 165 °C; In the four-stage aging heat treatment, the holding time of the third-stage aging heat treatment is 1 - 2 h; In the four-stage aging heat treatment, the temperature of the fourth-stage aging heat treatment is 174 - 180 °C; In the above-mentioned four-stage aging heat treatment, the holding time of the fourth-stage aging heat treatment is 4 to 6 hours.

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