A large frame type aluminum alloy product and a method for manufacturing the same

Abstract

The present application relates to the technical field of frame type aluminum alloy preparation, and specifically discloses a preparation method of large frame type aluminum alloy products, which comprises the following steps: pretreatment: preparing a support ring and a support template for standby; processing an aluminum alloy ingot into a ring piece; re-melting and heating: forming a nested piece in the support ring, and re-melting and heating the nested piece; forging a frame: transferring the nested piece after re-melting and heating to a forging platform, symmetrically arranging the support templates on both sides of the nested piece, and forming a combined die with the nested piece and the support templates, and a mandrel passing through the combined die and capable of driving the combined die to rotate; rotating the combined die during the forging process to change the forging surface, and forging until the ring piece is shaped into a frame piece; and heat treatment: taking out the frame piece, and obtaining the frame type aluminum alloy product after heat treatment. The present application has high production efficiency and low cost, the prepared frame type aluminum alloy product has good mechanical properties and excellent overall performance, and can better meet the demand of aerospace for aluminum alloy frame pieces.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy frame manufacturing technology, specifically to a large aluminum alloy frame product and its manufacturing method. Background Technology

[0002] Alloy frame products with length and width exceeding 3 meters are ultra-large load-bearing components and are important structural parts of aircraft. They are generally made of high-strength aluminum alloys to meet the stringent requirements of aircraft for structural strength, lightweighting, and reliability. The current mainstream processing method in the industry is sheet metal blanking followed by CNC milling. However, this technical route has significant limitations: First, material utilization is low. Because a large amount of redundant material needs to be removed from the entire sheet metal during milling, the actual material utilization rate is less than 10%, resulting in serious resource waste. Second, there is a bottleneck in production efficiency. The milling process requires multiple passes and high-precision machining of ultra-large sheet metal, leading to a lengthy production cycle that is difficult to match the high-efficiency delivery requirements of modern aerospace manufacturing. Cost control is also a challenge. Low material utilization combined with a long processing cycle directly increases the overall manufacturing cost of the product, limiting its potential for large-scale application. Furthermore, when using milling, the original deformation flow lines of the material cannot match the actual structural shape of the part, resulting in severe cutoff of the flow lines. This problem directly causes a significant decrease in the allowable value of the part's actual performance, significantly limiting its performance and potential for improvement during service.

[0003] However, conventional forging processes for such large frame-like components present challenges due to their complex workflow and the tendency for uneven deformation at the corners during molding, resulting in low elongation and poor overall performance. While 3D printing can precisely mold large frame-like parts, its performance still falls short of the requirements for load-bearing structural components, particularly those in aerospace applications. Therefore, the production and processing of such large alloy frame-like products urgently need improvement. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a method for preparing large frame-type aluminum alloy products, so as to further improve the comprehensive performance of large frame-type aluminum alloy products while increasing production efficiency and reducing costs.

[0005] The technical problem solved by this invention is to provide a large frame-type aluminum alloy product with excellent comprehensive performance, so as to better meet the needs of aerospace components.

[0006] The technical problem solved by this invention is achieved by the following technical solution:

[0007] A method for preparing a large frame-type aluminum alloy product includes the following steps:

[0008] Pretreatment: Prepare support rings and support templates for later use; process aluminum alloy ingots into ring parts;

[0009] Reheating: The cold support ring is placed inside the hot ring to form a nested part. The nested part is then reheated in the furnace so that the expansion of the support ring is greater than the thermal expansion of the ring to form an interference fit and generate radial compressive stress.

[0010] Forging frame: The nested part that has undergone reheat treatment is transferred to the forging platform. The support templates are symmetrically arranged on both sides of the nested part. The nested part and the support templates form a combined mold. The mandrel passes through the combined mold and can drive the combined mold to rotate. During the forging process, the combined mold rotates to change the forging surface. The forging continues until the ring is formed into a frame, and the inner frame edge of the frame is flush with the edge of the support template.

[0011] Heat treatment: Remove the frame and heat treat it to obtain aluminum alloy frame products.

[0012] Furthermore, in the pretreatment step, the thickness of the support ring is consistent with that of the ring component.

[0013] Furthermore, in the preprocessing step, the ratio of the outer diameter of the ring to the length of the outer diagonal of the frame is 1~1.05:1; the ratio of the inner diameter of the ring to the length of the inner diagonal of the frame is 0.95~1:1; the outer diameter of the support ring matches the inner diameter of the ring; and the length and width of the support template are consistent with the length and width of the inner frame of the frame, respectively.

[0014] Furthermore, in the pretreatment step, the support ring is made of aluminum alloy ingot or aluminum alloy forging, and the support template is made of mold steel.

[0015] Furthermore, in the pretreatment step, the aluminum alloy ingot is heated to 440~480℃ and held for 10~14h, then punched after multi-directional forging, and then ring rolled to obtain a ring.

[0016] Furthermore, in the reheating step, the nested parts are reheated at 440~480℃. When the temperature of the support ring rises to 320~380℃, the reheating is completed.

[0017] Furthermore, the interference fit between the support ring and the ring member is 0.7~0.9%.

[0018] Furthermore, the frame-type aluminum alloy product is a 2050 aluminum alloy frame or a 7050 aluminum alloy frame.

[0019] Furthermore, the length and width of the frame-type aluminum alloy product are both greater than or equal to 3000mm.

[0020] Furthermore, in the forging frame step, a flat anvil single-sided pressing method is used for forging.

[0021] Large frame-type aluminum alloy products, made by any of the methods described above, have a tensile strength greater than 560 MPa, a yield strength greater than 520 MPa, and an elongation greater than 10.5%.

[0022] Beneficial Effects: The method for preparing large frame-type aluminum alloy products described in this invention employs ring rolling with a continuously flowing ring component. A cold-state support ring and a hot-state ring component are nested to form an interference fit. This fitted body, along with a support template, constitutes a combined mold. Forging utilizes a combination of unilateral forging and rotary continuous forging, solving the problems of low performance, low production efficiency, and high cost associated with existing large frame-type aluminum alloy products. This invention features a simple preparation process, high production efficiency, and high material utilization. Compared to the traditional sheet metal blanking and CNC milling process, the material utilization rate of this invention increases from 15% to 65%, while the single-piece processing cycle is shortened from at least 15 days to within seven days, demonstrating significant practical application value.

[0023] The aluminum alloy frame products prepared by this invention have excellent mechanical properties, with a tensile strength greater than 560 MPa, a yield strength greater than 520 MPa, uniform local deformation at the four corners of the frame, and an elongation greater than 10.5%. They exhibit excellent overall performance and can better meet the needs of aerospace for aluminum alloy frame components. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the combined mold in the forging frame step of the present invention.

[0025] Figure 2 This is a schematic diagram of the nested component in this invention.

[0026] Figure 3 This is a schematic diagram of the frame-type aluminum alloy product structure in this invention.

[0027] Figure 4 This is a metallographic diagram of the corner of the aluminum alloy frame in Embodiment 1 of the present invention.

[0028] Figure 5 This is a metallographic diagram of the corner of the aluminum alloy frame in Embodiment 2 of the present invention.

[0029] Figure 6 This is a metallographic diagram of the corner of the aluminum alloy frame in Comparative Example 1 of the present invention.

[0030] Figure 7 This is a metallographic diagram of the corner of the aluminum alloy frame in Comparative Example 2 of the present invention.

[0031] The components include: 1. Ring; 2. Support ring; 3. Mandrel; 4. Bolt assembly; 5. Support template; 6. Positioning block. Detailed Implementation

[0032] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments.

[0033] Example 1

[0034] The present invention discloses a method for preparing large frame-type aluminum alloy products, wherein the large frame-type aluminum alloy products are 2050 aluminum alloy frame parts; the preparation method includes the following steps:

[0035] Preprocessing:

[0036] Use scrap aluminum alloy forgings to process support ring 2 with a diameter of 3650mm, a thickness of 150mm, and an inner diameter of 400mm for later use;

[0037] Two support templates 5 are fabricated using 5CrNiMo alloy steel. The length and width of the support templates 5 are both 2600mm, and the thickness is 80mm. The support templates 5 have a through hole in the center, which matches the inner hole of the support ring 2.

[0038] The aluminum alloy ingot was heated to 460℃ in a heating furnace and held for 12 hours. After holding, it was forged into a multi-directional billet. After the billet was forged, it was held at 460℃ for 4 hours, and then punched and rolled to obtain a ring with an outer diameter of 4250mm.

[0039] Reheating: A nesting element is formed within the heated ring 1 of the support ring 2, which is in a cold state at room temperature. The nesting element structure is as follows... Figure 2 As shown, the nested parts are returned to the furnace and kept at 460℃. The temperature of the support ring 2 blank is monitored. When the temperature reaches 350℃, the expansion of the support ring 2 is greater than the thermal expansion of the ring 1, forming an interference fit to generate radial compressive stress. At this time, the interference fit range is 0.7~0.9%.

[0040] Forging Frame: The nested part, after being reheated in the furnace, is transferred to the forging platform. The support templates 5 are symmetrically arranged on both sides of the nested part. The nested part and the support templates 5 form a combined mold. The structure of the combined mold is as follows: Figure 1 As shown, the nested component and the support template 5 are fixed by the positioning block 6 and the bolt assembly 4. The mandrel 3 passes through the combined mold and can drive the combined mold to rotate under the action of external force. A flat anvil single-sided pressing method is adopted, and during the forging process, the ring 1 and the support ring 2, which is interference-fitted with the ring 1, deform simultaneously. During the forging process, the combined mold components can rotate sequentially to change the forging surface, forging until the ring 1 is formed into a frame, and the inner frame edge of the frame is flush with the edge of the support template. The frame structure is as follows... Figure 3As shown, the frame dimensions are 3000mm×3000mm on the outside, 2600mm×2600mm on the inside, and 150mm in thickness.

[0041] Heat treatment: The frame is removed and heated to 510℃, held for 5 hours. After holding, it is quenched in water at room temperature. The quenched blank is then cold-deformed, with the expansion amount controlled at 3%. After cold deformation, aging treatment is performed at 145℃ for 40 hours. The resulting aluminum alloy frame is obtained after heat treatment.

[0042] The metallographic structure of the corner of the aluminum alloy frame prepared in this embodiment is shown in the figure below. Figure 4 As shown.

[0043] Example 2

[0044] The present invention discloses a method for preparing large frame-type aluminum alloy products, wherein the large frame-type aluminum alloy products are 7050 aluminum alloy frame parts; the preparation method includes the following steps:

[0045] Preprocessing:

[0046] Use scrap aluminum alloy forgings to process support ring 2 with a diameter of 3650mm, a thickness of 150mm, and an inner diameter of 400mm for later use;

[0047] Two support templates 5 are fabricated using 5CrNiMo alloy steel. The length and width of the support templates 5 are both 2600mm, and the thickness is 80mm. The support templates 5 have a through hole in the center, which matches the inner hole of the support ring 2.

[0048] The aluminum alloy ingot was heated to 450℃ in a heating furnace and held for 12 hours. After holding, it was forged into a multi-directional billet. After the billet was forged, it was held at 450℃ for 4 hours, and then punched and rolled to obtain a ring with an outer diameter of 4250mm.

[0049] Reheating: A nesting element is formed within the heated ring 1 of the support ring 2, which is in a cold state at room temperature. The nesting element structure is as follows... Figure 2 As shown, the nested parts are returned to the furnace and kept warm at 450℃; the temperature of the support ring 2 blank is monitored. When the temperature reaches 320℃, the expansion of the support ring 2 is greater than the thermal expansion of the ring 1, forming an interference fit to generate radial compressive stress. At this time, the interference fit range is 0.7~0.9%.

[0050] Forging Frame: The nested part, after being reheated in the furnace, is transferred to the forging platform. The support templates 5 are symmetrically arranged on both sides of the nested part. The nested part and the support templates 5 form a combined mold. The structure of the combined mold is as follows: Figure 1As shown, the nested part and the support template 5 are fixed by the positioning block 6 and the bolt assembly 4. The mandrel 3 passes through the combined mold and can drive the combined mold to rotate under the action of external force. The forging is carried out by single-sided pressing with a flat anvil. During the forging process, the ring 1 and the support ring 2 that is interference-fitted with the ring 1 deform simultaneously. During the forging process, the combined mold can rotate in sequence to change the forging surface. The forging continues until the ring 1 is formed into a frame, and the inner frame edge of the frame is flush with the edge of the support template. The frame structure is as follows. Figure 3 As shown, the frame dimensions are 3000mm×3000mm on the outside, 2600mm×2600mm on the inside, and 150mm in thickness.

[0051] Heat treatment: The frame is removed and heated to 475℃ for 5 hours. After holding, it is quenched in water at room temperature. The quenched blank is then cold-deformed, with the expansion amount controlled at 1.5%. After cold deformation, aging treatment is performed at 120℃ for 8 hours, followed by treatment at 160℃ for 12 hours. The resulting aluminum alloy frame is obtained after heat treatment.

[0052] The metallographic structure of the corner of the aluminum alloy frame prepared in this embodiment is shown in the figure below. Figure 5 As shown.

[0053] Compare with Example 1

[0054] The large frame-type aluminum alloy product described in this comparative example is a 7050 aluminum alloy frame; its manufacturing method includes the following steps:

[0055] Preprocessing:

[0056] Use scrap aluminum alloy forgings to process support ring 2 with a diameter of 3650mm, a thickness of 150mm, and an inner diameter of 400mm for later use;

[0057] Two support templates 5 are fabricated using 5CrNiMo alloy steel. The length and width of the support templates 5 are both 2600mm, and the thickness is 80mm. The support templates 5 have a through hole in the center, which matches the inner hole of the support ring 2.

[0058] The aluminum alloy ingot was heated to 450℃ in a heating furnace and held for 12 hours. After holding, it was forged into a multi-directional billet. After the billet was forged, it was held at 450℃ for 4 hours, and then punched and rolled to obtain a ring with an outer diameter of 4250mm.

[0059] Reheating: A nesting element is formed within the heated ring 1 of the support ring 2, which is in a cold state at room temperature. The nesting element structure is as follows... Figure 2 As shown, the nested parts are returned to the furnace and kept warm at 450℃; the temperature of the support ring 2 blank is monitored, and when the temperature reaches 260℃, the next step is carried out.

[0060] Forging Frame: The nested part, after being reheated in the furnace, is transferred to the forging platform. The support templates 5 are symmetrically arranged on both sides of the nested part. The nested part and the support templates 5 form a combined mold. The structure of the combined mold is as follows: Figure 1 As shown, the nested part and the support template 5 are fixed by the positioning block 6 and the bolt assembly 4. The mandrel 3 passes through the combined mold and can drive the combined mold to rotate under the action of external force. The forging is carried out by single-sided pressing with a flat anvil. During the forging process, the ring 1 and the support ring 2 that is interference-fitted with the ring 1 deform simultaneously. During the forging process, the combined mold can rotate in sequence to change the forging surface. The forging continues until the ring 1 is formed into a frame, and the inner frame edge of the frame is flush with the edge of the support template. The frame structure is as follows. Figure 3 As shown, the frame dimensions are 3000mm×3000mm on the outside, 2600mm×2600mm on the inside, and 150mm in thickness.

[0061] Heat treatment: The frame is removed and heated to 475℃ for 5 hours. After holding, it is quenched in water at room temperature. The quenched blank is then cold-deformed, with the expansion amount controlled at 1.5%. After cold deformation, aging treatment is performed at 120℃ for 8 hours, followed by treatment at 160℃ for 12 hours. The resulting aluminum alloy frame is obtained after heat treatment.

[0062] The metallographic structure of the corner of the aluminum alloy frame prepared in this comparative example is shown in the figure below. Figure 6 As shown.

[0063] Compare with Example 2

[0064] The large frame-type aluminum alloy product described in this comparative example is a 7050 aluminum alloy frame; its manufacturing method includes the following steps:

[0065] Preprocessing:

[0066] Use scrap aluminum alloy forgings to process support ring 2 with a diameter of 3650mm, a thickness of 150mm, and an inner diameter of 400mm for later use;

[0067] Two support templates 5 are fabricated using 5CrNiMo alloy steel. The length and width of the support templates 5 are both 2600mm, and the thickness is 80mm. The support templates 5 have a through hole in the center, which matches the inner hole of the support ring 2.

[0068] The aluminum alloy ingot was heated to 450℃ in a heating furnace and held for 12 hours. After holding, it was forged into a multi-directional billet. After the billet was forged, it was held at 450℃ for 4 hours, and then punched and rolled to obtain a ring with an outer diameter of 4250mm.

[0069] Reheating: A nesting element is formed within the heated ring 1 of the support ring 2, which is in a cold state at room temperature. The nesting element structure is as follows... Figure 2As shown, the nested parts are returned to the furnace and kept warm at 450℃; the temperature of the support ring 2 blank is monitored. When the temperature reaches 320℃, the expansion of the support ring 2 is greater than the thermal expansion of the ring 1, forming an interference fit to generate radial compressive stress. At this time, the interference fit range is 0.7~0.9%.

[0070] Forging Frame: The nested part, after being reheated in the furnace, is transferred to the forging platform. The support templates 5 are symmetrically arranged on both sides of the nested part. The nested part and the support templates 5 form a combined mold. The structure of the combined mold is as follows: Figure 1 As shown, the nested part and the support template 5 are fixed by the positioning block 6 and the bolt assembly 4. The mandrel 3 passes through the combined mold and can drive the combined mold to rotate under the action of external force. The forging is carried out by single-sided segmented pressing with a flat anvil. During the forging process, the ring 1 and the support ring 2 that is interference-fitted with the ring 1 deform simultaneously. During the forging process, the combined mold can rotate in sequence to change the forging surface. The forging continues until the ring 1 is formed into a frame, and the inner frame edge of the frame is flush with the edge of the support template. The frame structure is as follows. Figure 3 As shown, the frame dimensions are 3000mm×3000mm on the outside, 2600mm×2600mm on the inside, and 150mm in thickness.

[0071] Heat treatment: The frame is removed and heated to 475℃ for 5 hours. After holding, it is quenched in water at room temperature. The quenched blank is then cold-deformed, with the expansion amount controlled at 1.5%. After cold deformation, aging treatment is performed at 120℃ for 8 hours, followed by treatment at 160℃ for 12 hours. The resulting aluminum alloy frame is obtained after heat treatment.

[0072] The metallographic structure of the corner of the aluminum alloy frame prepared in this comparative example is shown in the figure below. Figure 7 As shown.

[0073] Compare with Example 3

[0074] This comparative example uses traditional sheet metal blanking and CNC milling for processing. The dimensions of the 7050 aluminum alloy frame are 3000mm×3000mm on the outside, 2600mm×2600mm on the inside, and 150mm thick.

[0075] The lowest performance values ​​at the corners of the aluminum alloy frames prepared in Examples 1-2 and Comparative Examples 1-3 were tested. The testing method was based on GB / T / 228.1-2021 Tensile Tests for Metallic Materials. The results are shown in Table 1.

[0076]

[0077] As shown in Table 1, the aluminum alloy frame prepared by this invention has a high elongation at the corners and excellent mechanical properties. Figures 4-7Metallographic analysis shows that the fine grain structure of the aluminum alloy frame prepared by the present invention is uniformly distributed along the deformation direction, while local grain inhomogeneity exists in Comparative Examples 1 and 2, which is presumably caused by the inhomogeneity of the deformation mode.

[0078] In traditional forging processes similar to the frame forging process, segmented local forging deformation is mostly used, which easily damages the original deformation flow lines of the ring, leading to inhomogeneity in the microstructure and uneven grain distribution in the product. Furthermore, for the semi-closed mold system used in this method, segmented local forging results in uncontrollable dimensions. This invention creatively employs a combination of a support template and a support ring. When combined with segmented local forging, as in Comparative Example 2 and the appendix… Figure 7 As shown, the results are still unsatisfactory. This invention employs a combination of a support template and a support ring to create the necessary conditions for pressing, which, combined with the pressing process, ensures that the resulting product has a uniform internal structure and controllable overall dimensions.

[0079] Furthermore, compared with the traditional sheet metal blanking and CNC milling method in Comparative Example 3, the mechanical properties of the aluminum alloy frame prepared by the present invention are improved, and the material utilization rate can be increased from the traditional 15% to 65%, an increase of about 50%, greatly reducing material costs. At the same time, the single-piece processing cycle is shortened from more than 15 days to less than 7 days, greatly improving production efficiency.

[0080] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing large frame-type aluminum alloy products, characterized in that, Includes the following steps: Pre-treatment: Prepare support rings and support templates for later use; process aluminum alloy ingots into rings; the ratio of the outer diameter of the ring to the outer diagonal length of the frame is 1~1.05:1; the ratio of the inner diameter of the ring to the inner diagonal length of the frame is 0.95~1:1; the outer diameter of the support ring matches the inner diameter of the ring; the length and width of the support template are consistent with the length and width of the inner frame of the frame, respectively; Reheating: The cold support ring is placed inside the hot ring to form a nested part. The nested part is then reheated in the furnace, causing the expansion of the support ring to exceed the thermal expansion of the ring, thus creating an interference fit and generating radial compressive stress. The interference fit between the support ring and the ring is 0.7~0.9%. Forging frame: The nested part that has undergone reheat treatment is transferred to the forging platform. The support templates are symmetrically arranged on both sides of the nested part. The nested part and the support templates form a combined mold. The mandrel passes through the combined mold and can drive the combined mold to rotate. During the forging process, the combined mold rotates to change the forging surface. Forging continues until the ring is formed into a frame and the inner frame edge of the frame is flush with the edge of the support template. Heat treatment: Remove the frame and heat treat it to obtain aluminum alloy frame products.

2. The method for preparing large frame-type aluminum alloy products as described in claim 1, characterized in that, In the pretreatment step, the thickness of the support ring is consistent with that of the ring component.

3. The method for preparing large frame-type aluminum alloy products as described in claim 1, characterized in that, In the pretreatment step, the support ring is made of aluminum alloy ingot or aluminum alloy forging, and the support template is made of mold steel.

4. The method for preparing large frame-type aluminum alloy products as described in claim 1, characterized in that, In the pretreatment step, the aluminum alloy ingot is heated to 440~480℃ and held for 10~14h. After multi-directional forging and blanking, it is punched and then ring rolled to obtain the ring part.

5. The method for preparing large frame-type aluminum alloy products as described in claim 1, characterized in that, In the reheating process, the nested parts are reheated at 440~480℃. When the temperature of the support ring rises to 320~380℃, the reheating is completed.

6. The method for preparing large frame-type aluminum alloy products as described in claim 1, characterized in that, In the forging process, a flat anvil single-sided pressing method is used for forging.

7. The method for preparing large frame-type aluminum alloy products as described in claim 1, characterized in that, The frame-type aluminum alloy products are 2050 aluminum alloy frames or 7050 aluminum alloy frames; the length and width of the frame-type aluminum alloy products are both greater than or equal to 3000mm.

8. Large frame-type aluminum alloy products, characterized in that, It is prepared by the method described in any one of claims 1 to 7, and has a tensile strength greater than 560 MPa, a yield strength greater than 520 MPa, and an elongation greater than 10.5%.

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