Arc bending forming method for 2xxx series aluminum alloy inclined T profile

Abstract

The invention relates to the technical field of bending forming, and provides a 2xxx series aluminum alloy inclined T profile arc bending forming method which comprises the following steps that a top bending mold is installed on a jacking platform, and the two sides of the top bending mold are each provided with a chuck; the two chucks are symmetrically arranged on the two sides of the top bending die. Clamping the two ends of the profile subjected to solid solution heat treatment on the chucks on the corresponding sides; the top-bending die ascends until the highest point of the top-bending die makes contact with the profile, and the height is recorded as the reference height; the jacking platform pushes the top bending die to gradually rise from the reference height until the profile is completely attached to the top bending die; the two chucks rotate and pitch up along with the ascending process of the top bending die; and the residual stress in the profile is released. Therefore, in the bending forming process of the sectional material, the clamping head is assisted to rotate and pitch up, so that the situation that the clamping part of the sectional material cracks due to large stress concentration is avoided while large bending deformation of the sectional material is achieved. And large-amplitude bending forming of the high-strength aluminum alloy is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of bending and forming, and in particular relates to an arc bending forming method for a 2xxx series aluminum alloy oblique T-profile. Background Art

[0002] The stretch-bending process is suitable for forming large-size, large-section, and high-precision parts. The currently mature aluminum profile stretch-bending process is mainly applied to low-strength 6-series aluminum alloys or small-section profiles. The profile has a small cross-section, low deformation resistance, and is easy to control.

[0003] The aviation industry primarily uses 2XXX and 7XXX series aluminum alloys, which are known for their high strength, high bending springback, and unique cross-sectional structures. Stress concentrations at the ribs can easily lead to cracking. Therefore, existing stretch-bending processes are unsuitable for arc-bending aluminum profiles used in aviation. Furthermore, the high bow height of curved parts makes existing equipment unable to fully achieve the desired curve.

[0004] In summary, the existing technology has obvious inconveniences and defects in actual use, so it is necessary to improve it. Summary of the Invention

[0005] In response to the above-mentioned defects, the present invention mainly provides a method for arc bending of 2xxx series aluminum alloy inclined T-profiles, which solves the technical problem that the existing stretch bending process is not applicable to the stretch bending of 2xxx series aluminum alloy profiles.

[0006] In order to solve the above problems, the present invention provides a method for arc bending of a 2xxx series aluminum alloy oblique T-profile, comprising the following steps:

[0007] S1, installing the top bending mold on the jacking platform, and respectively setting a chuck on both sides of the top bending mold; the two chucks are symmetrically set on both sides of the top bending mold;

[0008] S2, hoisting the profile after solution heat treatment above the top bending mold; clamping both ends of the profile to the clamping heads on the corresponding sides; the cross-section of the profile is T-shaped;

[0009] S3, the lifting platform pushes the bending mold up until the highest point of the bending mold contacts the profile, the lifting platform stops, and the height of the bending mold at this moment is recorded as the reference height;

[0010] S4, the lifting platform pushes the top bending mold to gradually rise from the reference height until the profile is completely attached to the top bending mold; as the top bending mold rises, the two chucks rotate upward;

[0011] S5, the two clamps apply tensile force to the bent profile to release the residual stress inside the profile.

[0012] According to the arc bending forming method of 2xxx series aluminum alloy inclined T-profiles of the present invention, in the step S2, the profile is lifted by a soft sling and sent to the top of the top bending mold by a crane; after the two ends of the profile are clamped to the chucks on the corresponding side, the soft sling is removed.

[0013] According to the arc bending forming method of 2xxx series aluminum alloy oblique T-profiles of the present invention, the chuck includes jaws for clamping the profile; the jaws are fixedly connected to the mold base facing the outer facade of the top bending mold.

[0014] According to the arc bending forming method of the 2xxx series aluminum alloy oblique T-profile of the present invention, the mold base is further fixedly connected to an arc-shaped mold, and the arc-shaped mold has an arc-shaped surface for forming surface contact with the profile.

[0015] According to the arc bending forming method of the 2xxx series aluminum alloy oblique T-profile of the present invention, before the step S3 is performed, the two clamps simultaneously apply tension to straighten the profile.

[0016] According to the arc bending forming method of the 2xxx series aluminum alloy oblique T-profile of the present invention, the straightening process includes: gradually increasing the tensile force of the two clamps to 600T, and then unloading to complete the straightening of the profile.

[0017] According to the arc bending forming method of the 2xxx series aluminum alloy oblique T-profile of the present invention, the top bending mold includes a left top bending mold group and a right top bending mold group; the left top bending mold group and the right top bending mold group each have two top bending modules; a groove is formed between the two top bending modules for accommodating the raised structure of the profile.

[0018] According to the arc bending forming method of 2xxx series aluminum alloy inclined T-profiles of the present invention, in the step S3, when the protruding structure of the profile completely enters the groove, the lifting platform stops, and the height of the bending mold at this moment is set as the reference height.

[0019] According to the arc bending forming method of the 2xxx series aluminum alloy oblique T-profile of the present invention, in the S5 step, the tensile force applied by the two clamps is 800T, which is maintained for 30 seconds and then unloaded to complete the release of residual stress inside the profile.

[0020] According to the arc bending forming method of the 2xxx series aluminum alloy oblique T-profile of the present invention, the step S4 comprises:

[0021] The top bending die gradually rises from the base height to 450mm. The rising speed of the top bending die in this process is 6-8mm / s. The straightening force applied to the testing chuck is 100T.

[0022] The top bending mold is increased from 450mm to 1050mm;

[0023] Keep the height of the top bending mold at 1050mm, and rotate the two chucks upward, with the elevation angle gradually increasing from 0° to 7°;

[0024] The top bending mold is increased from 1050mm to 1450mm;

[0025] Keep the height of the top bending mold at 1450mm, and rotate the two chucks upward, with the elevation angle gradually increasing from 7° to 14°;

[0026] The top bending mold is increased from 1450mm to 1850mm.

[0027] In summary, the present invention utilizes the upward rotation of the chuck during the bending process to achieve significant bending deformation while preventing cracking caused by significant stress concentration at the clamping site. This allows for significant bending of high-strength aluminum alloys. After forming, a reverse tensile force is applied to release residual stress, ensuring product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the arc bending forming operation of the present invention;

[0029] Figure 2 yes Figure 1 Schematic diagram of the structure of the chuck;

[0030] Figure 3 yes Figure 1 Schematic diagram of the structure of the profile and top bending mold;

[0031] Figure 4 Schematic diagram of the profile inspection after bending and forming of the profile of the present invention;

[0032] In the figure: 1-chuck, 11-jaw, 12-die base, 13-arc-shaped die; 2-lifting platform, 21-left top bending module, 22-right top bending module, 23-top bending module, 24-left profile detection plate, 25-right profile detection plate; 100-profile. DETAILED DESCRIPTION

[0033] See also Figure 1 The present invention provides a method for arc bending of a 2xxx series aluminum alloy oblique T-profile, comprising the following steps:

[0034] S1, install the top bending mold on the jacking platform 2, and set a clamp 1 on both sides of the top bending mold; the two clamps 1 are symmetrically set on both sides of the top bending mold;

[0035] Combine Figure 2 Optionally, the two chucks 1 can be fine-tuned horizontally in the direction of the arrow (or in the opposite direction of the arrow) to improve the accuracy of their symmetrical distribution on both sides of the top bending mold.

[0036] S2, hanging the profile 100 after the solution heat treatment above the top bending die; clamping the two ends of the profile 100 to the chuck 1 on the corresponding side; the cross-section of the profile 100 is T-shaped;

[0037] Combine Figure 2 As an embodiment, in step S2, the profile 100 is lifted by a soft sling and is sent to the top of the top bending mold by a crane; after the two ends of the profile 100 are clamped to the clamping head 1 on the corresponding side, the soft sling is removed;

[0038] The use of soft slings can protect the surface of the profile 100 from being scratched, and also facilitates fine-tuning during clamping so that the center of the profile 100 coincides with the center of the top bending mold, thereby ensuring the subsequent molding quality.

[0039] As an embodiment, the chuck 1 of the present invention includes a jaw 11 for clamping the profile 100; the jaw 11 is fixedly connected to a mold base 12 facing the outer facade of the top bending mold; when the profile 100 is bent, the mold base 12 comes into contact with the profile 100, avoiding excessive stress concentration at the clamping part of the profile 100 and the jaw 11, causing cracks in this part of the profile 100.

[0040] Furthermore, the mold base 12 is also fixedly connected to the arc-shaped mold 13, and the arc-shaped mold 13 has an arc-shaped surface for forming surface contact with the profile 100; as the bending process progresses, the profile 100 gradually forms surface contact with the arc-shaped mold 13, thereby increasing the contact area, reducing or even eliminating stress concentration, and enabling the profile 100 to be subjected to a larger bending force to complete the bending forming.

[0041] S3, the lifting platform 2 pushes the bending mold up until the highest point of the bending mold contacts the profile 100, and the lifting platform 2 stops, and the height of the bending mold at this moment is recorded as the reference height;

[0042] As a preferred solution, before the step S3 is performed, the two clamps 1 simultaneously apply tension to straighten the profile 100 to eliminate deformation and achieve high dimensional accuracy in the bending process.

[0043] Furthermore, the straightening process includes: gradually increasing the tensile force of the two clamps 1 to 600T, and then unloading to complete the straightening of the profile 100.

[0044] As an embodiment, the top bending mold includes a left top bending mold group 21 and a right top bending mold group 22;

[0045] See also Figure 3 As an embodiment, the left top bending module 21 and the right top bending module 22 each have two top bending modules 23; a groove for accommodating the raised structure of the profile 100 is formed between the two top bending modules 23;

[0046] Furthermore, in step S3, when the protruding structure of the profile 100 completely enters the groove, the lifting platform 2 stops, and the height of the bending mold at this moment is recorded as the reference height;

[0047] S4, the lifting platform 2 pushes the top bending mold to gradually rise from the reference height until the profile 100 is completely attached to the top bending mold;

[0048] As the top bending die rises, the two clamps 1 rotate upward; while gradually bending and deforming the profile 100, the stress concentration at the clamping parts of the two is reduced, so that the profile 100 can be bent to a greater extent.

[0049] As an embodiment, in step S4, the bending die is gradually raised from the reference height to 450 mm, and the rising speed of the bending die during this process is 6-8 mm / s; the straightening force applied to the chuck 1 is 100 T;

[0050] The top bending die is raised from 450mm to 1050mm; the straightening force applied to the test chuck 1 is 300T;

[0051] Maintaining the height of the top bending mold at 1050mm, the two chucks 1 are rotated upward, and the elevation angle gradually increases from 0° to 7°. During this process, the straightening force on the detection chuck 1 is significantly reduced.

[0052] The top bending die is raised from 1050mm to 1450mm; the straightening force on the test chuck 1 is 450T;

[0053] Keep the height of the top bending mold at 1450mm, and rotate the two chucks 1 upward, with the elevation angle gradually increasing from 7° to 14°;

[0054] The top bending die is raised from 1450mm to 1850mm; the straightening force applied to the test chuck 1 is 600T;

[0055] The present invention divides the bending process of the profile 100 into multiple lifting stages, supplemented by the upward rotation of the chuck 1. This achieves significant bending deformation of the profile 100 while reducing the straightening force on the chuck 1, thus preventing cracking caused by significant stress concentration in the clamping area of ​​the profile 100. This achieves significant bending of high-strength aluminum alloys.

[0056] S5, the two clamps 1 apply a tensile force to the bent profile 100 to release the residual stress inside the profile 100;

[0057] As an embodiment, in the step S5, the tensile force applied by the two chucks 1 is 800T, which is maintained for 30 seconds and then unloaded to complete the release of the residual stress inside the profile 100;

[0058] S6, remove the chuck 1 and take out the formed profile 100;

[0059] See also Figure 4 As an embodiment, a checking fixture is used to check the curvature deviation of the outer contour of the formed profile 100.

[0060] The inventors used the forming method of the present invention to bend and form multiple profile 100 products, and tested the curvature of the outer contour of the food. The deviation did not exceed 1.9 mm, which was significantly lower than the standard value requirement of 2.28 mm, and the products were qualified.

[0061] Optionally, the inspection tool includes a left profile inspection plate 24 and a right profile inspection plate 25 to facilitate the inspection operation.

[0062] In summary, the present invention provides a method for bending 2xxx series aluminum alloy oblique T-profiles. By utilizing the upward rotation of a chuck during the bending process, the method achieves significant bending deformation while preventing cracking caused by significant stress concentration at the clamping site. This method enables significant bending of high-strength aluminum alloys. After forming, a reverse tensile force is applied to release residual stress, thereby ensuring product quality.

[0063] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for arc bending of a 2xxx series aluminum alloy oblique T-profile, characterized in that: The steps include: S1, installing the top bending mold on the jacking platform, and respectively setting a chuck on both sides of the top bending mold; the two chucks are symmetrically set on both sides of the top bending mold; S2, hoisting the profile after solution heat treatment above the top bending mold; clamping both ends of the profile to the clamping heads on the corresponding sides; the cross-section of the profile is T-shaped; S3, the lifting platform pushes the bending mold up until the highest point of the bending mold contacts the profile, the lifting platform stops, and the height of the bending mold at this moment is recorded as the reference height; S4, the lifting platform pushes the top bending mold to gradually rise from the reference height until the profile is completely fitted on the top bending mold; as the top bending mold rises, the two chucks rotate upward; S5, the two clamps apply tensile force to the bent profile to release the residual stress inside the profile.

2. The arc bending forming method of the 2xxx series aluminum alloy oblique T-profile according to claim 1, characterized in that: In step S2, the profile is lifted by a soft sling and sent to the top of the top bending mold by a crane; after the two ends of the profile are clamped to the clamping heads on the corresponding side, the soft sling is removed.

3. The arc bending forming method of the 2xxx series aluminum alloy oblique T-profile according to claim 1, characterized in that: The clamping head comprises a jaw for clamping the profile; the jaw is fixedly connected to the mold base facing the outer facade of the top bending mold.

4. The arc bending forming method of the 2xxx series aluminum alloy oblique T-profile according to claim 3, characterized in that: The mold base is also fixedly connected to an arc-shaped mold, and the arc-shaped mold has an arc-shaped surface for forming surface contact with the profile.

5. The arc bending forming method of the 2xxx series aluminum alloy oblique T-profile according to claim 1, characterized in that: Before the step S3 is performed, the two clamps simultaneously apply tension to straighten the profile.

6. The arc bending forming method of the 2xxx series aluminum alloy oblique T-profile according to claim 5, characterized in that: The straightening process includes: gradually increasing the tensile force of the two clamps to 600T, and then unloading to complete the straightening of the profile.

7. The arc bending forming method of the 2xxx series aluminum alloy oblique T-profile according to claim 1, characterized in that: The top bending mold includes a left top bending mold group and a right top bending mold group; the left top bending mold group and the right top bending mold group each have two top bending modules; a groove for accommodating the raised structure of the profile is formed between the two top bending modules.

8. The arc bending forming method of the 2xxx series aluminum alloy oblique T-profile according to claim 7, characterized in that: In the step S3, when the raised structure of the profile completely enters the groove, the lifting platform stops, and the height of the top bending mold at this moment is recorded as the reference height.

9. The arc bending forming method of the 2xxx series aluminum alloy oblique T-profile according to claim 1, characterized in that: In the step S5, the tensile force applied by the two chucks is 800T, which is maintained for 30 seconds and then unloaded to complete the release of the residual stress inside the profile.

10. The arc bending forming method of a 2xxx series aluminum alloy oblique T-profile according to any one of claims 1 to 9, characterized in that: The S4 step includes: The top bending die gradually rises from the base height to 450mm. The rising speed of the top bending die in this process is 6-8mm / s. The straightening force applied to the testing chuck is 100T. The top bending mold is increased from 450mm to 1050mm; Keep the height of the top bending mold at 1050mm, and rotate the two chucks upward, with the elevation angle gradually increasing from 0° to 7°; The top bending mold is increased from 1050mm to 1450mm; Keep the height of the top bending mold at 1450mm, and rotate the two chucks upward, with the elevation angle gradually increasing from 7° to 14°; The top bending mold is increased from 1450mm to 1850mm.

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