Forging deformation method for improving comprehensive mechanical property of 7050 aluminum alloy

Abstract

The invention provides a forging deformation method for improving the comprehensive mechanical property of 7050 aluminum alloy, which comprises the following steps: heating a 7050 aluminum alloy ingot, carrying out a first group of three-upsetting and three-drawing forging process, heating again, carrying out a second group of three-upsetting and three-drawing forging process, continuously heating, and carrying out a third group of three-upsetting and three-drawing forging process to obtain a blank; heating and quenching the blank obtained in the previous step, and performing axial cold compression deformation to obtain a deformed blank; and after the deformed blank is subjected to a four-stage aging heat treatment process, a forging stock is obtained. Through the nine-upsetting and nine-drawing forging cogging process, the overall mechanical property uniformity of the material can be improved, grains are refined, the overall performance advantages of the material are brought into play, the comprehensive mechanical property of the 7050 aluminum alloy is improved, and therefore the problems that an existing 7050 product is insufficient in long transverse strength, short transverse strength and ductility are solved; the original defects in the cast ingot can be welded, and the blank flaw detection quality is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of forging and preparing 7050 aluminum alloy rings, and relates to a forging deformation method of 7050 aluminum alloy, and in particular 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 aircraft reinforcement frames, load-bearing beams and joints, rocket body transition rings, engine end frames, and armed equipment structural parts. With the further improvement of the service requirements of the above 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, comprehensive performance is provided mainly by optimizing alloy composition, improving ingot metallurgical quality, multi-directional forging grain refinement, and optimizing ring rolling and heat treatment processes, such as: CN201910428933.3 discloses a method for regulating the coarse second phase of 2219 aluminum alloy rings. By adopting seven upsetting and six drawing processes combined with medium and low temperature ring rolling processes, the coarse second phase of 2219 is effectively refined and the comprehensive performance is improved. However, this method is not suitable for processing 7xxx with high alloy content.

[0003] CN202111534337.7 discloses a forging method for 7050 aluminum alloy forgings. By adopting four-upsetting and four-drawing forging, the grain structure is effectively refined and the comprehensive performance is improved. However, the forging performance obtained by this method cannot meet the needs of specific application scenarios.

[0004] CN202210837020.9 discloses a forging and heat treatment process for large 7050 aluminum alloy rings. A method for forging large 7050 aluminum alloy rings is developed by adopting three-upsetting and three-drawing processes combined with multi-stage solid solution and aging processes. The performance of the rings obtained by this method cannot meet the needs of specific application scenarios.

[0005] In the existing disclosed methods, refining the grains by optimizing the forging method is an effective means to improve the overall performance. However, the 7050 alloy has a high content and the accumulation of forging deformation is prone to damage and defects such as cracks.

[0006] Therefore, developing a new deformation process that can meet the requirements of further grain refinement and reduce forging deformation damage is an urgent problem that needs to be solved for 7050 aluminum alloy. It is also one of the urgent problems that many front-line researchers in the industry need to solve. Summary of the invention

[0007] In view of this, the technical problem to be solved by the present invention is to provide a forging deformation method of 7050 aluminum alloy, in particular, 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-level aging heat treatment method, can improve the uniformity of the overall mechanical properties of the material and exert the overall performance advantages of the material by refining the grains.

[0008] The present invention provides a forging deformation method for a 7050 aluminum alloy, comprising the following steps: (1) After heating the 7050 aluminum alloy ingot, a first set of three-upsetting and three-drawing forging processes are performed, and then the ingot is heated again and a second set of three-upsetting and three-drawing forging processes are performed, and then the ingot is heated again and a third set of three-upsetting and three-drawing forging processes are performed to obtain a billet; In the first set of three-upsetting and three-drawing forging processes, the deformation rate of the first upsetting is 55%~60%; the height-to-diameter ratio of the first drawing is (2.4~2.6):1; The deformation rate of the second upsetting is 50%~55%; the height-to-diameter ratio of the second drawing is (2.3~2.5):1; The deformation rate of the third upsetting is 45%~50%; the height-to-diameter ratio of the third drawing is (2.2~2.4):1; (2) heating the blank obtained in the above step, quenching it, and performing axial cold compression deformation to obtain a deformed blank; (3) The deformed billet is subjected to a four-stage aging heat treatment process to obtain a forging billet.

[0009] Preferably, the 7050 aluminum alloy ingot is heated to a temperature of 450-470° C.; The heating time of the 7050 aluminum alloy ingot is 5 to 20 hours; In the first set of three-upsetting and three-drawing forging processes, the forging speed is 1-5 mm / s.

[0010] Preferably, the reheating time is 3 to 10 hours; The reheating temperature is 400-450°C; The time of continuing heating is 4 to 15 hours; The temperature of the continued heating is 450-470°C.

[0011] Preferably, in the first set of three-upsetting and three-drawing forging steps, the deformation rate of the first upsetting is greater than the deformation rate of the second upsetting; In the first set of three-upsetting and three-drawing forging processes, the deformation rate of the second upsetting is greater than the deformation rate of the third upsetting; In the first set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the first drawing is greater than the height-to-diameter ratio of the second drawing; In the first set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the second drawing is greater than the height-to-diameter ratio of the third drawing.

[0012] Preferably, in the second group of three-upsetting and three-drawing forging steps, the forging speed is 5-10 mm / s; In the second group of three-upsetting and three-drawing forging processes, the deformation rate of the first upsetting is 60%~65%; In the second set of three-upsetting and three-drawing forging processes, the height-to-diameter ratio of the first drawing is (2.5-2.7): 1; In the second set of three-upsetting and three-drawing forging processes, the deformation rate of the second upsetting is 55%~60%; In the second set of three-upsetting and three-drawing forging processes, the height-to-diameter ratio of the second drawing is (2.4-2.6): 1; In the second group of three-upsetting and three-drawing forging processes, the deformation rate of the third upsetting is 50%~55%; In the second group of three-upsetting and three-drawing forging processes, the height-to-diameter ratio of the third drawing is (2.3~2.5):1.

[0013] Preferably, the deformation rate of the first upset in the forging process of the first group of three upsets and three draws is less than the deformation rate of the first upset in the forging process of the second group of three upsets and three draws; The aspect ratio of the first drawing in the forging process of the first set of three upsetting and three drawing is smaller than the aspect ratio of the first drawing in the forging process of the second set of three upsetting and three drawing; In the second set of three-upsetting and three-drawing forging processes, the deformation rate of the first upsetting is greater than the deformation rate of the second upsetting; In the second set of three-upsetting and three-drawing forging processes, the deformation rate of the second upsetting is greater than the deformation rate of the third upsetting; In the second set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the first drawing is greater than the height-to-diameter ratio of the second drawing; In the second set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the second drawing is greater than the height-to-diameter ratio of the third drawing.

[0014] Preferably, in the third group of three-upsetting and three-drawing forging processes, the forging speed is 1-5 mm / s; In the third group of three-upsetting and three-drawing forging processes, the deformation rate of the first upsetting is 65% to 70%; In the third set of three-upsetting and three-drawing forging processes, the height-to-diameter ratio of the first drawing is (2.6-2.8): 1; In the third set of three-upsetting and three-drawing forging processes, the deformation rate of the second upsetting is 60% to 65%; In the third set of three-upsetting and three-drawing forging processes, the height-to-diameter ratio of the second drawing is (2.5-2.7): 1; In the third group of three-upsetting and three-drawing forging processes, the deformation rate of the third upsetting is 55% to 60%; In the third group of three-upsetting and three-drawing forging processes, the height-to-diameter ratio of the third drawing is (2.4-2.6):1.

[0015] Preferably, the deformation rate of the first upset in the forging process of the second group of three upsets and three draws is less than the deformation rate of the first upset in the forging process of the third group of three upsets and three draws; The aspect ratio of the first drawing in the forging process of the second set of three upsetting and three drawing is smaller than the aspect ratio of the first drawing in the forging process of the third set of three upsetting and three drawing; In the third set of three-upsetting and three-drawing forging steps, the deformation rate of the first upsetting is greater than the deformation rate of the second upsetting; In the third set of three-upsetting and three-drawing forging steps, the deformation rate of the second upsetting is greater than the deformation rate of the third upsetting; In the third set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the first drawing is greater than the height-to-diameter ratio of the second drawing; In the third set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the second drawing is greater than the height-to-diameter ratio of the third drawing.

[0016] Preferably, the 7050 aluminum alloy comprises a 7050 aluminum alloy ring; After step (1), the method further includes performing one or more of the steps of punching, expanding and ring rolling on the blank; The wall thickness deformation rate of the hole expansion accounts for 70% to 90% of the total wall thickness deformation rate of the hole expansion and ring rolling; The heating temperature in step (2) is 470-480°C; The heating time in step (2) is 120 to 570 minutes; The quenching method includes water quenching; The 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%.

[0017] Preferably, 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 to 12 hours; 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 to 3 hours; 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 to 2 hours; In the four-stage aging heat treatment, the temperature of the fourth stage aging heat treatment is 174-180°C; In the four-stage aging heat treatment, the holding time of the fourth stage aging heat treatment is 4 to 6 hours.

[0018] Beneficial effect: The present invention provides a forging deformation method of 7050 aluminum alloy, comprising the following steps: firstly, heating the 7050 aluminum alloy ingot, performing the first set of three-upsetting and three-drawing forging processes, then heating again, performing the second set of three-upsetting and three-drawing forging processes, then continuing to heat, performing the third set of three-upsetting and three-drawing forging processes, and obtaining a blank; then heating the blank obtained in the above steps, quenching, and performing axial cold compression deformation to obtain a deformed blank; finally, performing a four-level aging heat treatment process on the deformed blank to obtain a forged blank. Compared with the prior art, the present invention proposes a method for forming an ingot based on multi-pass multi-directional forging to improve the comprehensive mechanical properties of the 7050 aluminum alloy. The present invention refines the grains of the billet through a forging blanking process of nine upsettings and nine drawing, that is, firstly, the ingot plasticity is fully improved by three upsettings and three drawing at high temperature and low speed, then the ingot is deformed by three upsettings and three drawing at medium temperature and high speed to fully deform and refine the grains, and finally, the damage is suppressed by three upsettings and three drawing at high temperature and low speed to further refine the grains, and the billet is returned to the heating furnace for insulation between each two times to maintain the internal temperature of the billet and restore the plasticity, and then a specific upsetting and drawing ratio within a single group of upsetting and drawing lengths and parameter associations between each group of upsetting and drawing lengths are further achieved, and a four-stage aging heat treatment process is used to improve the temperature uniformity during the aging process, and the uniformity is taken into account while improving the overall mechanical properties of the material.

[0019] The nine-upsetting and nine-drawing forging blanking process provided by the present invention can improve the uniformity of the overall mechanical properties of the material, and exert the overall performance advantages of the material by refining the grains, thereby solving the problems of insufficient long transverse and short transverse strength and elongation in the existing 7050 products, and can improve the overall mechanical properties and performance uniformity of the product, and can also weld the original defects in the ingot, thereby improving the flaw detection quality of the blank.

[0020] Experimental results show that the 7050 forgings of the present invention have fine and uniform grain structure and high comprehensive mechanical properties, especially the long lateral elongation and short lateral elongation reach more than 6%, which is higher than the existing conventional process and can meet the high performance requirements of specific application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a metallographic picture of the forging blank prepared in Example 1 of the present invention; Figure 2 This is a metallographic picture of the forging blank prepared in Comparative Example 1 of the present invention; Figure 3 This is a metallographic picture of the forging blank prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0022] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples, but 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.

[0023] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0024] There is no particular restriction on the purity of all raw materials in the present invention. The present invention preferably uses industrial pure materials or materials with conventional purity requirements in the field of 7050 series aluminum alloy preparation.

[0025] The brands and abbreviations of all raw materials of the present invention are conventional brands and abbreviations in the art. Each brand and abbreviation is clear and definite in the field of its related use. Those skilled in the art can purchase them from the market or prepare them by conventional methods according to the brands, abbreviations and corresponding uses.

[0026] The abbreviations of the processes used in the present invention are all conventional abbreviations in the field. The specific steps and conventional parameters of each abbreviation are clear and definite in its relevant field. Those skilled in the art can implement them in a conventional manner based on the abbreviations.

[0027] Anisotropy: The property of a material having different performance in all directions. Since the overall improvement of material performance is limited, in general, reducing the anisotropy of material performance helps meet the requirements of the user.

[0028] Isotropy: The property of a material that has the same or similar properties in all directions, i.e. uniformity, which is the opposite of anisotropy.

[0029] Grain refinement: Make the crystal size in the material smaller and the number more. This effect can improve the strength and elongation of the material at the same time.

[0030] Upsetting deformation rate: the percentage of the height difference before and after upsetting to the height before upsetting.

[0031] Aspect ratio: The ratio of the height to the diameter of the blank. In order to make the upsetting deformation more uniform and effective, the blank needs to be controlled to reach a certain aspect ratio during drawing.

[0032] Performance directions: longitudinal, long transverse, and short transverse, generally referring to the directions of best to worst mechanical properties of the material.

[0033] Shape direction: For rings, they are circumferential, radial and axial. When the performance of the ring is determined, the shape direction can correspond to the performance direction.

[0034] The present invention provides a forging deformation method for a 7050 aluminum alloy, comprising the following steps: (1) After heating the 7050 aluminum alloy ingot, a first set of three-upsetting and three-drawing forging processes are performed, and then the ingot is heated again and a second set of three-upsetting and three-drawing forging processes are performed, and then the ingot is heated again and a third set of three-upsetting and three-drawing forging processes are performed to obtain a billet; In the first set of three-upsetting and three-drawing forging processes, the deformation rate of the first upsetting is 55%~60%; the height-to-diameter ratio of the first drawing is (2.4~2.6):1; The deformation rate of the second upsetting is 50%~55%; the height-to-diameter ratio of the second drawing is (2.3~2.5):1; The deformation rate of the third upsetting is 45%~50%; the height-to-diameter ratio of the third drawing is (2.2~2.4):1; (2) heating the blank obtained in the above step, quenching it, and performing axial cold compression deformation to obtain a deformed blank; (3) The deformed billet is subjected to a four-stage aging heat treatment process to obtain a forging billet.

[0035] The invention first heats a 7050 aluminum alloy ingot, performs a first set of three-upsetting and three-drawing forging processes, then heats it again, performs a second set of three-upsetting and three-drawing forging processes, and then continues to heat it, performs a third set of three-upsetting and three-drawing forging processes to obtain a blank.

[0036] In the present invention, the heating temperature of the 7050 aluminum alloy ingot is preferably 450-470°C, more preferably 455-465°C, and more preferably 458-462°C.

[0037] In the present invention, the heating time of the 7050 aluminum alloy ingot is preferably 5 to 20 hours, more preferably 8 to 17 hours, and more preferably 11 to 14 hours.

[0038] In the present invention, in the first set of three-upsetting and three-drawing forging steps, the forging speed is preferably 1-5 mm / s, more preferably 2-4 mm / s, and more preferably 2.2-3.6 mm / s.

[0039] In the present invention, in the first set of three-upsetting and three-drawing forging steps, the deformation rate of the first upsetting is preferably 55% to 60%, more preferably 56% to 59%, and more preferably 57% to 58%.

[0040] In the present invention, in the first set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the first drawing is preferably (2.4-2.6):1, more preferably (2.44-2.56):1, and more preferably (2.48-2.52):1.

[0041] In the present invention, in the first set of three-upsetting and three-drawing forging steps, the deformation rate of the second upsetting is preferably 50%-55%, more preferably 51%-54%, and more preferably 52%-53%.

[0042] In the present invention, in the first set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the second drawing is preferably (2.3-2.5):1, more preferably (2.34-2.46):1, and more preferably (2.38-2.42):1.

[0043] In the present invention, in the first set of three-upsetting and three-drawing forging steps, the deformation rate of the third upsetting is preferably 45% to 50%, more preferably 46% to 49%, and more preferably 47% to 48%.

[0044] In the present invention, in the first set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the third drawing is preferably (2.2-2.4):1, more preferably (2.24-2.36):1, and more preferably (2.28-2.32):1.

[0045] In the present invention, the reheating time is preferably 3 to 10 hours, more preferably 4 to 9 hours, more preferably 5 to 8 hours, and more preferably 6 to 7 hours.

[0046] In the present invention, the reheating temperature is preferably 400-450°C, more preferably 420-440°C, and more preferably 428-438°C.

[0047] In the present invention, in the first set of three-upsetting and three-drawing forging steps, the deformation rate of the first upsetting is preferably greater than the deformation rate of the second upsetting; In the present invention, in the first set of three-upsetting and three-drawing forging steps, the deformation rate of the second upsetting is preferably greater than the deformation rate of the third upsetting; In the present invention, in the first set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the first drawing is preferably greater than the height-to-diameter ratio of the second drawing; In the present invention, in the first set of three-upsetting and three-drawing forging steps, the aspect ratio of the second drawing is preferably greater than the aspect ratio of the third drawing.

[0048] In the present invention, in the second set of three-upsetting and three-drawing forging steps, the forging speed is preferably 5-10 mm / s, more preferably 6-9 mm / s, and more preferably 7.2-8.6 mm / s.

[0049] In the present invention, in the second set of three-upsetting and three-drawing forging steps, the deformation rate of the first upsetting is preferably 60%-65%, more preferably 61%-64%, and more preferably 62%-63%.

[0050] In the present invention, in the second set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the first drawing is preferably (2.5-2.7):1, more preferably (2.54-2.66):1, and more preferably (2.58-2.62):1.

[0051] In the present invention, in the second set of three-upsetting and three-drawing forging steps, the deformation rate of the second upsetting is preferably 55% to 60%, more preferably 56% to 59%, and more preferably 57% to 58%.

[0052] In the present invention, in the second set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the second drawing is preferably (2.4-2.6):1, more preferably (2.44-2.56):1, and more preferably (2.48-2.52):1.

[0053] In the present invention, in the second set of three-upsetting and three-drawing forging steps, the deformation rate of the third upsetting is preferably 50%-55%, more preferably 51%-54%, and more preferably 52%-53%.

[0054] In the present invention, in the second set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the third drawing is preferably (2.3-2.5):1, more preferably (2.34-2.46):1, and more preferably (2.38-2.42):1.

[0055] In the present invention, the continued heating time is preferably 4 to 15 hours, more preferably 6 to 13 hours, and more preferably 8 to 11 hours.

[0056] In the present invention, the temperature of the continued heating is preferably 450-470°C, more preferably 455-465°C, and more preferably 458-462°C.

[0057] In the present invention, the deformation rate of the first upset in the forging process of the first set of three upsets and three draws is preferably smaller than the deformation rate of the first upset in the forging process of the second set of three upsets and three draws.

[0058] In the present invention, the aspect ratio of the first drawing in the forging process of the first set of three upsetting and three drawing is preferably smaller than the aspect ratio of the first drawing in the forging process of the second set of three upsetting and three drawing.

[0059] In the present invention, in the second set of three-upsetting and three-drawing forging steps, the deformation rate of the first upsetting is preferably greater than the deformation rate of the second upsetting.

[0060] In the present invention, in the second set of three-upsetting and three-drawing forging steps, the deformation rate of the second upsetting is greater than the deformation rate of the third upsetting.

[0061] In the present invention, in the second set of three-upsetting and three-drawing forging steps, the aspect ratio of the first drawing is preferably greater than the aspect ratio of the second drawing.

[0062] In the present invention, in the second set of three-upsetting and three-drawing forging steps, the aspect ratio of the second drawing is preferably greater than the aspect ratio of the third drawing.

[0063] In the present invention, in the third set of three-upsetting and three-drawing forging steps, the forging speed is preferably 1-5 mm / s, more preferably 2-4 mm / s, and more preferably 2.2-3.6 mm / s.

[0064] In the present invention, in the third set of three-upsetting and three-drawing forging process, the deformation rate of the first upsetting is preferably 65% ​​to 70%, more preferably 66% to 69%, and more preferably 67% to 68%.

[0065] In the present invention, in the third set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the first drawing is preferably (2.6-2.8):1, more preferably (2.64-2.76):1, and more preferably (2.68-2.72):1.

[0066] In the present invention, in the third set of three-upsetting and three-drawing forging process, the deformation rate of the second upsetting is preferably 60% to 65%, more preferably 61% to 64%, and more preferably 62% to 63%.

[0067] In the present invention, in the third set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the second drawing is preferably (2.5-2.7):1, more preferably (2.54-2.66):1, and more preferably (2.58-2.62):1.

[0068] In the present invention, in the third set of three-upsetting and three-drawing forging steps, the deformation rate of the third upsetting is preferably 55% to 60%, more preferably 56% to 59%, and more preferably 57% to 58%.

[0069] In the present invention, in the third set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the third drawing is preferably (2.4-2.6):1, more preferably (2.44-2.56):1, and more preferably (2.48-2.52):1.

[0070] In the present invention, the deformation rate of the first upset in the forging process of the second set of three upsets and three draws is preferably smaller than the deformation rate of the first upset in the forging process of the third set of three upsets and three draws.

[0071] In the present invention, the aspect ratio of the first drawing in the forging process of the second set of three upsetting and three drawing is preferably smaller than the aspect ratio of the first drawing in the forging process of the third set of three upsetting and three drawing.

[0072] In the present invention, in the third set of three-upsetting and three-drawing forging steps, the deformation rate of the first upsetting is preferably greater than the deformation rate of the second upsetting.

[0073] In the present invention, in the third set of three-upsetting and three-drawing forging steps, the deformation rate of the second upsetting is preferably greater than the deformation rate of the third upsetting.

[0074] In the present invention, in the third set of three-upsetting and three-drawing forging steps, the aspect ratio of the first drawing is preferably greater than the aspect ratio of the second drawing.

[0075] In the present invention, in the third set of three-upsetting and three-drawing forging steps, the aspect ratio of the second drawing is preferably greater than the aspect ratio of the third drawing.

[0076] Specifically, the specific parameters of the three sets of three-upsetting and three-drawing forging processes are shown in Table 1: Table 1

[0077]

[0078] In the present invention, the 7050 aluminum alloy preferably includes a 7050 aluminum alloy ring.

[0079] In the present invention, the component content of the 7050 aluminum alloy may be specifically as shown in Table 2: Table 2

[0080]

[0081] In the present invention, after step (1), the process preferably further includes one or more steps of punching, expanding and ring rolling the blank, and more preferably includes multiple steps of punching, expanding and ring rolling the blank.

[0082] In the present invention, the wall thickness deformation rate of the hole expansion preferably accounts for 70% to 90% of the total wall thickness deformation rate of the hole expansion and ring rolling, more preferably 74% to 86%, and more preferably 78% to 82%.

[0083] The present invention further heats and quenches the blank obtained in the above steps, and performs axial cold compression deformation to obtain a deformed blank.

[0084] In the present invention, the heating temperature in step (2) is preferably 470-480°C, more preferably 472-478°C, and more preferably 474-476°C.

[0085] In the present invention, the heating time in step (2) is preferably 120 to 570 min, more preferably 200 to 500 min, and more preferably 300 to 400 min.

[0086] In the present invention, the quenching method preferably includes water quenching.

[0087] In the present invention, the interval time between the axial cold compression deformation and the quenching is preferably less than or equal to 3 hours, more preferably less than or equal to 2 hours, and more preferably less than or equal to 1 hour.

[0088] 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 more preferably less than or equal to 3%.

[0089] The present invention finally subjects the deformed blank to a four-stage aging heat treatment process to obtain a forging blank.

[0090] In the present invention, in the four-stage aging heat treatment, the temperature of the first stage aging heat treatment is preferably 100-130°C, more preferably 105-125°C, and more preferably 110-120°C.

[0091] 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 hours, more preferably 8.5 to 11.5 hours, more preferably 9 to 11 hours, and more preferably 9.5 to 10.5 hours.

[0092] In the present invention, in the four-stage aging heat treatment, the temperature of the second stage aging heat treatment is preferably 135-145°C, more preferably 137-143°C, and more preferably 139-141°C.

[0093] In the present invention, in the four-stage aging heat treatment, the holding time of the second stage aging heat treatment is preferably 2-3 hours, more preferably 2.2-2.8 hours, and more preferably 2.4-2.6 hours.

[0094] In the present invention, in the four-stage aging heat treatment, the temperature of the third stage aging heat treatment is preferably 155-165°C, more preferably 157-163°C, and more preferably 159-161°C.

[0095] 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 hours, more preferably 1.2 to 1.8 hours, and more preferably 1.4 to 1.6 hours.

[0096] In the present invention, in the four-stage aging heat treatment, the temperature of the fourth stage aging heat treatment is preferably 174-180°C, more preferably 175-179°C, and more preferably 176-178°C.

[0097] 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 hours, more preferably 4.4 to 5.6 hours, and more preferably 4.8 to 5.2 hours.

[0098] The present invention is a complete and refined overall technical solution, which better improves the uniformity of the overall mechanical properties of the 7050 aluminum alloy material, and further exerts the overall performance advantages of the material by refining the grains. The forging deformation method for improving the comprehensive mechanical properties of the 7050 aluminum alloy preferably includes the following steps: The present invention refines the grains of the billet through a nine-upsetting and nine-drawing forging process, and uses a four-stage aging heat treatment process to improve the temperature uniformity during the aging process, thereby improving the overall mechanical properties of the material while taking uniformity into consideration.

[0099] Specific technical solution (taking 7050T7652 ring as an example): Step 1: Heat the ingot to 450-470°C; Step 2: The ingot is subjected to a three-upsetting and three-drawing forging process, and then returned to the furnace to be heated at the original temperature, and the three-upsetting and three-drawing processes are completed three times in this order; Step 3: Punch the blank, then expand the hole and roll the ring to a certain size; Step 4: Heat the blank to 470-480°C and then quench it, followed by axial cold compression deformation; Step 5: Perform four-level aging heat treatment on the blank in the range of 100~180℃.

[0100] Specifically, in the second step, the upsetting deformation rate is controlled at 45% to 70%, the height-to-diameter ratio of the billet after drawing is controlled at 2.2 to 2.8, and the last upsetting deformation rate does not exceed 60%.

[0101] Specifically, in the second step, the heating time between each three-upsetting and three-drawing process is not less than 3 hours to ensure the temperature recovery and damage repair of the blank.

[0102] Specifically, in the third step, the hole expansion and ring rolling processes cooperate to expand the size of the ring. The main deformation is hole expansion, and the wall thickness deformation rate accounts for more than 70%.

[0103] Specifically, the axial cold compression in the fourth step must be completed within 3 hours after the ring is quenched, and the cold deformation rate does not exceed 5%.

[0104] Specifically, the four-stage aging heat treatment may be performed at four temperature ranges of 121° C., 140° C., 160° C. and 177° C.

[0105] Specifically, in the fifth step, the holding time of the 121°C temperature section is 8 to 12 hours, the holding time of the 140°C temperature section is 2 to 3 hours, the holding time of the 160°C temperature section is 1 to 2 hours, and the holding time of the 177°C temperature section is 4 to 6 hours. The holding time of the 140°C and 160°C temperature sections should not be too long, and they are only used as transition temperature sections to ensure uniform temperature inside the billet.

[0106] The nine-upsetting and nine-drawing process of the present invention can also be replaced by other upsetting and drawing processes with more passes, such as ten-upsetting and ten-drawing. More multi-stage aging heat treatment schemes can be used to replace the four-stage aging scheme. Similar technical effects can also be obtained by using products of other alloy grades, states, and specifications.

[0107] 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 present invention proposes a method for ingot blanking deformation based on multi-pass multi-directional forging to improve the comprehensive mechanical properties of 7050 aluminum alloy. The present invention refines the grains of the billet through a forging blanking process of nine upsetting and nine drawing, that is, firstly 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, and returning the billet to the heating furnace for insulation between each two times to maintain the internal temperature of the billet and restore plasticity, and then further through a specific upsetting ratio in a single group of upsetting and drawing length and a parameter association between each group of upsetting and drawing length, and supplemented by a four-stage aging heat treatment process, thereby improving the temperature uniformity during the aging process, while improving the overall mechanical properties of the material while taking into account uniformity.

[0108] In order to further illustrate the present invention, a forging deformation method of a 7050 aluminum alloy provided by the present invention is described in detail below 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, and detailed implementation methods and specific operation processes are given only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention, and the protection scope of the present invention is not limited to the following embodiments.

[0109] Example 1 Step 1: Heat the ingot at 460°C for 12 hours; The second step: the ingot is subjected to a three-upsetting and three-drawing forging process, with a forging speed of 3 mm / s, the first upsetting is 57%, the height-to-diameter ratio of the first drawing is 2.5:1, the deformation rate of the second upsetting is preferably 52%, the height-to-diameter ratio of the second drawing is 2.4:1, the deformation rate of the third upsetting is 47%, and the height-to-diameter ratio of the third drawing is 2.3:1.

[0110] Step 3: Then return to the furnace and heat it, the heating temperature is 430℃, and the holding time is 6h; Step 4: subject the above-mentioned billet to a three-upsetting and three-drawing forging process, 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.

[0111] Step 5: Then return to the furnace and heat it at 460℃ for 10h; Step 6: The above billet is subjected to a three-upsetting and three-drawing forging process, the forging speed is 3 mm / s, the deformation rate of the first upsetting is 68%, the height-to-diameter ratio of the first drawing is 2.7:1, the deformation rate of the second upsetting is 62%, the height-to-diameter ratio of the second drawing is 2.6:1, the deformation rate of the third upsetting is 52%, and the height-to-diameter ratio of the third drawing is 2.5:1.

[0112] Step 7: Punch the blank, then expand the hole and roll the ring to a certain size; Step 8: Heat the blank to 475°C, keep it warm for 350 minutes, then quench it, and then perform axial cold compression deformation with a deformation of 3%; Step 9: Heat the blank to 120°C, keep it warm for 10 hours, continue to heat it to 140°C, keep it warm for 2.5 hours, then heat it to 160°C, keep it warm for 1.5 hours, and finally heat it to 177°C, keep it warm for 5 hours.

[0113] See also Figure 1 , Figure 1 This is a metallographic picture of the forging blank prepared in Example 1 of the present invention.

[0114] Comparative Example 1 Step 1: Heat the ingot at 460°C for 12 hours; The second step: the ingot is subjected to a three-upsetting and three-drawing forging process, with a forging speed of 3 mm / s, the first upsetting is 57%, the height-to-diameter ratio of the first drawing is 2.5:1, the deformation rate of the second upsetting is preferably 52%, the height-to-diameter ratio of the second drawing is 2.4:1, the deformation rate of the third upsetting is 47%, and the height-to-diameter ratio of the third drawing is 2.3:1.

[0115] Step 3: Then return to the furnace and heat it, the heating temperature is 430℃, and the holding time is 6h; Step 4: subject the above-mentioned billet to a three-upsetting and three-drawing forging process, 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.

[0116] Step 5: Punch the blank, then expand the hole and roll the ring to a certain size; Step 6: Heat the blank to 475°C, keep it warm for 350 minutes, then quench it, and then perform axial cold compression deformation with a deformation of 3%; Step 7: Heat the blank to 120°C, keep it warm for 10 hours, continue to heat it to 140°C, keep it warm for 2.5 hours, then heat it to 160°C, keep it warm for 1.5 hours, and finally heat it to 177°C, keep it warm for 5 hours.

[0117] See also Figure 2 , Figure 2 This is a metallographic picture of the forging blank prepared in Comparative Example 1 of the present invention.

[0118] Comparative Example 2 Step 1: Heat the ingot at 460°C for 12 hours; The second step: the ingot is subjected to a three-upsetting and three-drawing forging process, with a forging speed of 3 mm / s, the first upsetting is 57%, the height-to-diameter ratio of the first drawing is 2.5:1, the deformation rate of the second upsetting is preferably 52%, the height-to-diameter ratio of the second drawing is 2.4:1, the deformation rate of the third upsetting is 47%, and the height-to-diameter ratio of the third drawing is 2.3:1.

[0119] Step 3: Then return to the furnace and heat it, the heating temperature is 430℃, and the holding time is 6h; Step 4: subject the above-mentioned billet to a three-upsetting and three-drawing forging process, 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.

[0120] Step 5: Heat the blank to 120°C, keep it warm for 10 hours, continue to heat it to 140°C, keep it warm for 2.5 hours, then heat it to 160°C, keep it warm for 1.5 hours, and finally heat it to 177°C, keep it warm for 5 hours.

[0121] See also Figure 3 , Figure 3 This is a metallographic picture of the forging blank prepared in Comparative Example 2 of the present invention.

[0122] See Table 3, which shows the performance data of 7050 aluminum alloy forging billets prepared in the embodiments of the present invention and the comparative examples.

[0123] Table 3

[0124]

[0125] The forging deformation method for improving the comprehensive mechanical properties of 7050 aluminum alloy provided by the present invention is described in detail above. The principle and implementation method of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and its core idea of ​​the present invention, including the best mode, and also enables any technician in the field to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements that are not different from the textual expression of the claims, or if they include equivalent structural elements that are not substantially different from the textual expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A forging deformation method for improving the comprehensive mechanical properties of 7050 aluminum alloy, characterized in that: The following steps are involved: (1) After heating the 7050 aluminum alloy ingot, a first set of three-upsetting and three-drawing forging processes are performed, and then the ingot is heated again and a second set of three-upsetting and three-drawing forging processes are performed, and then the ingot is heated again and a third set of three-upsetting and three-drawing forging processes are performed to obtain a billet; In the first set of three-upsetting and three-drawing forging processes, the deformation rate of the first upsetting is 55%~60%; the height-to-diameter ratio of the first drawing is (2.4~2.6):1; The deformation rate of the second upsetting is 50%~55%; the height-to-diameter ratio of the second drawing is (2.3~2.5):1; The deformation rate of the third upsetting is 45%~50%; the height-to-diameter ratio of the third drawing is (2.2~2.4):1; (2) heating the blank obtained in the above step, quenching it, and performing axial cold compression deformation to obtain a deformed blank; (3) The deformed billet is subjected to a four-stage aging heat treatment process to obtain a forging billet.

2. The forging deformation method according to claim 1, characterized in that: The heating temperature of the 7050 aluminum alloy ingot is 450-470° C. The heating time of the 7050 aluminum alloy ingot is 5 to 20 hours; In the first set of three-upsetting and three-drawing forging processes, the forging speed is 1-5 mm / s.

3. The forging deformation method according to claim 1, characterized in that: The reheating time is 3 to 10 hours; The reheating temperature is 400-450°C; The time of continuing heating is 4 to 15 hours; The temperature of the continued heating is 450-470°C.

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

5. The forging deformation method according to claim 1, characterized in that: In the second set of three-upsetting and three-drawing forging processes, the forging speed is 5-10 mm / s; In the second group of three-upsetting and three-drawing forging processes, the deformation rate of the first upsetting is 60%~65%; In the second set of three-upsetting and three-drawing forging processes, the height-to-diameter ratio of the first drawing is (2.5-2.7): 1; In the second set of three-upsetting and three-drawing forging processes, the deformation rate of the second upsetting is 55%~60%; In the second set of three-upsetting and three-drawing forging processes, the height-to-diameter ratio of the second drawing is (2.4-2.6): 1; In the second group of three-upsetting and three-drawing forging processes, the deformation rate of the third upsetting is 50%~55%; In the second group of three-upsetting and three-drawing forging processes, the height-to-diameter ratio of the third drawing is (2.3~2.5):

1.

6. The forging deformation method according to claim 1, characterized in that: The deformation rate of the first upset in the forging process of the first group of three upsets and three draws is less than the deformation rate of the first upset in the forging process of the second group of three upsets and three draws; The aspect ratio of the first drawing in the forging process of the first set of three upsetting and three drawing is smaller than the aspect ratio of the first drawing in the forging process of the second set of three upsetting and three drawing; In the second set of three-upsetting and three-drawing forging processes, the deformation rate of the first upsetting is greater than the deformation rate of the second upsetting; In the second set of three-upsetting and three-drawing forging processes, the deformation rate of the second upsetting is greater than the deformation rate of the third upsetting; In the second set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the first drawing is greater than the height-to-diameter ratio of the second drawing; In the second set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the second drawing is greater than the height-to-diameter ratio of the third drawing.

7. The forging deformation method according to claim 1, characterized in that: In the third group of three-upsetting and three-drawing forging processes, the forging speed is 1-5 mm / s; In the third group of three-upsetting and three-drawing forging processes, the deformation rate of the first upsetting is 65% to 70%; In the third set of three-upsetting and three-drawing forging processes, the height-to-diameter ratio of the first drawing is (2.6-2.8): 1; In the third set of three-upsetting and three-drawing forging processes, the deformation rate of the second upsetting is 60% to 65%; In the third set of three-upsetting and three-drawing forging processes, the height-to-diameter ratio of the second drawing is (2.5-2.7): 1; In the third group of three-upsetting and three-drawing forging processes, the deformation rate of the third upsetting is 55% to 60%; In the third group of three-upsetting and three-drawing forging processes, the height-to-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 upset in the forging process of the second group of three upsets and three draws is less than the deformation rate of the first upset in the forging process of the third group of three upsets and three draws; The aspect ratio of the first drawing in the forging process of the second set of three upsetting and three drawing is smaller than the aspect ratio of the first drawing in the forging process of the third set of three upsetting and three drawing; In the third set of three-upsetting and three-drawing forging steps, the deformation rate of the first upsetting is greater than the deformation rate of the second upsetting; In the third set of three-upsetting and three-drawing forging steps, the deformation rate of the second upsetting is greater than the deformation rate of the third upsetting; In the third set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the first drawing is greater than the height-to-diameter ratio of the second drawing; In the third set of three-upsetting and three-drawing forging steps, the height-to-diameter ratio of the second drawing is greater than the height-to-diameter ratio 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 step (1), the method further includes performing one or more of the steps of punching, expanding and ring rolling on the blank; The wall thickness deformation rate of the hole expansion accounts for 70% to 90% of the total wall thickness deformation rate of the hole expansion and ring rolling; The heating temperature in step (2) is 470-480°C; The heating time in step (2) is 120 to 570 minutes; The quenching method includes water quenching; The 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: 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 to 12 hours; 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 to 3 hours; 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 to 2 hours; In the four-stage aging heat treatment, the temperature of the fourth stage aging heat treatment is 174-180°C; In the four-stage aging heat treatment, the holding time of the fourth stage aging heat treatment is 4 to 6 hours.

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