A method for rolling rigid materials for aerospace right-angle profile frames with tapered corners

Abstract

This invention provides a method for bending rigid right-angle and tapered profile frames for aerospace applications, comprising the following steps: S1, cutting blanks to be bent from the base material according to requirements; S2, quenching the blanks to be bent; S3, straightening the blanks to be bent; S4, artificially aging the material obtained in step 3 to remove its internal stress; S5, bending the material obtained in step 4; S6, cutting and finishing the profile after bending in step 5 to produce the finished product. This invention provides a method for bending rigid right-angle and tapered profile frames for aerospace applications, employing a process flow of straight material quenching, straightening, artificial aging, and then bending. It rationally designs the bending process parameters, using different proportions of side-push values ​​for the left and right rollers, and simultaneously increasing the rotation values ​​of the left and right rollers to bend and form parts with acceptable dimensions.

Description

Technical Field

[0001] This invention belongs to the field of rocket profile frame forming, and in particular relates to a method for rolling and bending rigid materials for right-angle profile frames with tapered corners used in aerospace applications. Background Technology

[0002] The current-use carrier rocket profile frames are all formed using a stretch bending process. Stretching involves clamping both ends of a straight profile, applying tension while rotating it around a mold, and finally applying additional tension to form a bent part. The raw material for the stretch-bent finished product is 7A09 aluminum alloy, in an arc shape. This part is a semicircle with a diameter of Ф3350mm, and a right-angled vertical side with a 5° tapered angle. For roll bending of this profile frame, not only is the vertical side asymmetrical with a tapered angle, but the roll bending diameter is also very large—a Ф3350mm semicircle. Furthermore, this 7A09 material, after straight quenching and artificial aging, has a high profile hardness and a tensile strength exceeding 600MPa. Figure 6 As shown, this type of profile is difficult to roll and form, and is prone to twisting. The vertical edge of the finished product 1 is prone to gap 11 between the right angle 9 feet, and the bottom edge is prone to gap 11 between the platform 10.

[0003] The existing forming process is as follows: blanking, pre-bending forming, quenching, supplementary bending forming, manual finishing, artificial aging, manual finishing and inspection. The profile frame adopts the bending forming process. After supplementary bending forming, there is springback in the curvature and angle. The curvature springback is manifested by the part radius being 5mm smaller than the theoretical radius R1675. The angle springback is manifested by the gap between the vertical edge and the right angle ruler, and the gap between the bottom edge and the platform.

[0004] For the springback in curvature and angle, extensive manual trimming of the profile frame is required after the bending process, adjusting the curvature and vertical edge angle dimensions. This manual trimming is very extensive and labor-intensive for workers. Secondly, the raw material for this profile is 7A09 in the O state, requiring quenching and artificial aging strengthening. After the bending process, the trimmed parts are made into qualified parts. However, after artificial aging, the release of internal stress causes deformation, mainly manifested as a decrease in the curvature dimension and changes in flatness and angle. At this point, the parts have already hardened after artificial aging, making it difficult to achieve qualified dimensions through manual trimming, resulting in significant deviations from tolerances. Furthermore, the bending process of this profile frame requires quenching. After quenching, the bending and trimming process must be completed within 1.5 hours. Otherwise, if the time is too long, the parts will harden, and only 4 pieces can be produced in 1.5 hours, resulting in low production efficiency. Summary of the Invention

[0005] In view of this, the present invention aims to propose a rolling bending method for rigid materials of right-angle and tapered profile frames for aerospace applications, in order to solve the problems of large springback of curvature and angle, large amount of manual trimming, and low production efficiency when using existing stretch bending forming processes for profile frames.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] A method for rolling a rigid right-angle profile frame with tapered corners for aerospace applications includes the following steps: S1, cutting the blank to be rolled from the base material according to requirements; S2, quenching the blank to be rolled; S3, straightening the blank to be rolled; S4, artificially aging the material obtained in step 3 to remove its internal stress; S5, rolling the material obtained in step 4; S6, cutting and finishing the profile after the rolling process in step 5 to produce the finished product.

[0008] Furthermore, the base material is an L-shaped profile, with the cross-section of the first side of the base material being a trapezoidal or triangular structure, and the cross-section of the second side of the base material being a rectangular structure.

[0009] Furthermore, in step S2, the quenching temperature is 475±5℃, the quenching holding time is 35~38min, and the raw material is cooled by water after quenching.

[0010] Furthermore, the straightening process in step S3 involves inserting both ends of the raw material into the jaws of a bending machine, setting the bending force of the bending machine to 13t and the stretching amount to 5mm.

[0011] Furthermore, the artificial aging method in step S4 involves heating and heat preservation of the raw material at an aging temperature of 120±5℃ for 3 hours, then adjusting the aging temperature to 160±5℃ for 3 hours, followed by natural cooling.

[0012] Furthermore, the bending equipment used in step 5 is a four-axis bending machine. The four-axis bending machine includes a left roller, a right roller, an upper roller, and a lower roller mounted on the main frame. The upper roller is located above the lower roller, and the left and right rollers are located on both sides of the lower roller. Both the left and right rollers are driven rollers, while both the lower and upper rollers are driven rollers. The outer periphery of the raw material is located sequentially above the left roller, between the upper and lower rollers, and above the right roller, and the outer periphery of the raw material sequentially abuts against the outer periphery of the left roller, the outer periphery of the upper roller, the outer periphery of the lower roller, and the outer periphery of the right roller.

[0013] Furthermore, the outer periphery of the upper roller is used to position the first edge of the base material.

[0014] Furthermore, the lower roller is provided with a first annular mold groove around its periphery, and the first annular mold groove is used to position the first side and the second side of the base material, and the cross-section of the first annular mold groove is the same as the cross-section of the first side and the second side of the base material.

[0015] Furthermore, the left and right rollers push the blank material upwards to reduce its radius. The left and right rollers also push the blank material laterally, which is an axial movement. This lateral pushing prevents the blank material from twisting or warping during the bending process. The left and right rollers are each equipped with a rotation value, which is a left-right swing. This rotation can correct the angle of the first and second sides of the blank material. The left and right rollers have the same rotation value. The upper roller can slide vertically and presses the blank material profile downwards.

[0016] Furthermore, the method for performing the roll bending process in step 4 is as follows: the raw material profile is rolled and formed multiple times on a four-axis roll bending machine, and the side push value of the left and right rollers is increased each time the roll bending is performed, and the side push value of the left roller is always greater than the side push value of the right roller. The side push value of the left roller gradually increases with each roll bending, and the side push value of the right roller gradually increases with each roll bending. Each time the roll bending is performed, the rotation value of the left and right rollers is increased, and the rotation values ​​of the left and right rollers are the same. The upward push value is the same for each roll bending or decreases with each roll bending.

[0017] Compared to existing technologies, the aerospace-grade right-angle profile frame with tapered corners described in this invention has the following advantages: Roll bending can correct the curvature, flatness, and angular dimensions of the parts using rollers, eliminating the need for extensive manual finishing. Roll bending allows for the pre-quenching and artificial aging of the raw material profile before roll bending, thus preventing aging deformation caused by stretch bending. The pre-quenching of the raw material also improves production efficiency. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 This is a front view schematic diagram of a finished product formed by the rigid material roll bending method of a right-angle profile frame with tapered corners for aerospace applications, as described in an embodiment of the present invention.

[0020] Figure 2 This is a schematic cross-sectional view of the raw material as described in an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the state of the raw material being processed in a method for rolling a right-angle profile frame with tapered corners for aerospace applications, as described in an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram illustrating the state of the left roller bending the raw material according to an embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram illustrating the state of the upper and lower rollers bending the raw material according to an embodiment of the present invention;

[0024] Figure 6This is a schematic diagram of the cross-sectional deformation of a profile frame formed by the prior art as described in an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1-Finished product; 2-Raw material; 21-First side; 22-Second side; 3-Upper roller; 4-Lower roller; 5-Left roller; 6-Right roller; 7-Rotation direction of the left roller; 8-Side pushing direction of the left roller; 9-Ruler; 10-Platform; 11-Gap. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] like Figure 1-3As shown, the DQ5360 right-angle profile frame part will experience bending due to quenching deformation after the profile is hardened. Therefore, a process is adopted where the profile is first straightened after quenching, then artificially aged, and finally rolled and bent. By adjusting the rolling and bending process parameters, parts with qualified dimensions are produced. The design requirements for this profile frame are: radius deviation less than 1.5mm, gap between the bottom plane and the platform less than 1.5mm, and gap between the vertical edge angle and the right-angle ruler less than 0.8mm. Parts are considered qualified if all three indicators are met.

[0032] Therefore, the method for rolling rigid materials of this type of aerospace right-angle profile with tapered corner includes the following steps:

[0033] S1. Cut the blank material to be bent 2 from the base material according to the requirements;

[0034] The rough material 2 was cut to a length of 6262mm using a saw.

[0035] S2. Quenching treatment is performed on the blank material 2 to be bent.

[0036] The straight DQ5360 profile was quenched at a temperature of 475±5℃ and a holding time of 35~38min. After quenching, the raw material 2 was cooled with water.

[0037] S3. Straighten the blank material 2 to be bent.

[0038] Insert both ends of the DQ5360 profile into the jaws of the bending machine, set the bending force to 13t and the stretching amount to 5mm, and straighten the profile.

[0039] S4. Artificially age the material obtained in step 3 to remove its internal stress;

[0040] The artificial aging method involves heating and holding the raw material 2 at a temperature of 120±5℃ for 3 hours, then adjusting the aging temperature to 160±5℃ for 3 hours, followed by natural cooling.

[0041] S5. Perform a bending process on the material obtained in step 4.

[0042] The rolling bending equipment for the rolling bending process is a four-axis rolling bending machine. The four-axis rolling bending machine includes a left roller 5, a right roller 6, an upper roller 3, and a lower roller 4 installed on the main frame. The upper roller 3 is located above the lower roller 4. The left roller 5 and the right roller 6 are located on both sides of the lower roller 4. The left roller 5 and the right roller 6 are both driven rollers. The lower roller 4 and the upper roller 3 are both driven rollers. The outer periphery of the rough material 2 is located above the left roller 5, between the upper roller 3 and the lower roller 4, and above the right roller 6 in sequence. The outer periphery of the rough material 2 abuts against the outer periphery of the left roller 5, the outer periphery of the upper roller 3, the outer periphery of the lower roller 4, and the outer periphery of the right roller 6 in sequence.

[0043] like Figure 5As shown, the outer periphery of the upper roller 3 is used to position the first side 21 of the base material, and the outer periphery of the lower roller 4 is provided with a first annular mold groove, which is used to position the first side 21 and the second side 22 of the base material. The cross-section of the first annular mold groove is the same as the cross-section of the first side 21 and the second side 22 of the base material. The left roller 5 and the right roller 6 push the blank 2 upwards respectively. Pushing upwards can reduce the radius of the blank 2. The left roller 5 and the right roller 6 push the blank 2 laterally. The lateral push is an axial movement. The lateral push can prevent the blank 2 from twisting during the rolling bending process. The left roller 5 and the right roller 6 are respectively provided with rotation values. The rotation is a left and right swing. The rotation can correct the angle of the first side and the second side of the blank 2. The rotation values ​​of the left roller 5 and the right roller 6 are the same. The upper roller 3 can slide vertically and press the blank 2 profile downwards.

[0044] like Figure 4 As shown, the lateral push here refers to the left roller 5 and right roller 6 sliding along the axial direction. The lateral push value is the sliding displacement value of the left roller 5 and right roller 6 along the axial direction. The outer periphery of the left roller 5 and right roller 6 is provided with annular grooves. The outer periphery of the blank 2 is located in the annular grooves. The cross-section of the annular groove and the cross-section of the profile frame are mating dimensions. During roll bending, the two annular grooves are not on the same linear surface. The rotation refers to the lower end of the left roller 5 and right roller 6 being provided with arc-shaped roller tracks. The left roller 5 and right roller 6 can slide along the arc-shaped roller tracks. The rotation value is the sliding arc of the left and right rollers 5 and right roller 6 relative to the upper and lower rollers.

[0045] The method for performing the roll bending process in step 4 is as follows: the raw material 2 profile is rolled and formed multiple times on a four-axis roll bending machine. During each roll bending, the lateral push value of the left roller 5 and the right roller 6 is increased, and the lateral push value of the left roller 5 is always greater than that of the right roller 6. The lateral push value of the left roller 5 gradually increases with each roll bending, and the lateral push value of the right roller 6 gradually increases with each roll bending. The rotation values ​​of the left roller 5 and the right roller 6 are also increased, and the rotation values ​​of the left roller 5 and the right roller 6 are the same. The upward push value of the left roller 5 and the right roller 6 is the same for each roll bending or decreases with each roll bending.

[0046] In this embodiment, the bending equipment is a four-axis bending machine. The bending process parameters are the upward push value of the left roller 5 and the right roller 6, the side push value of the left roller 5 and the side push value of the right roller 6, and the rotation value of the left roller 5 and the right roller 6. These process parameters are used to adjust the curvature, flatness and angle dimensions of the parts. Because this profile is a right-angled vertical edge with a tapered corner, the part would normally form a twisted shape with raised ends when rolled and formed. Furthermore, the vertical edge angle and flatness would have gaps with the right-angle ruler and platform. After multiple trials and adjustments to the process parameters, the lateral push values ​​of left roller 5 and right roller 6 were increased, with left roller 5 having a larger lateral push value than right roller 6. The rotation values ​​of left roller 5 and right roller 6 were also increased, with both values ​​set to 1. After three roll forming processes, the lateral push value of left roller 5 was 1.5 greater than that of right roller 6 in the first two rolls, and 1 greater in the third roll. After forming, the part's curvature gap with the template was 1mm, its flatness gap with the platform was 0.6mm, and its angle gap with the right-angle ruler was 0.6mm (the drawing requires the curvature gap to be less than or equal to 1.5mm, the flatness gap to the platform to be less than or equal to 1.5mm, and the angle gap with the right-angle ruler to be less than or equal to 0.8mm). The part dimensions met the drawing tolerance requirements, and a dimensionally qualified part was formed.

[0047] The roll bending process parameters and part values ​​are shown in the table below:

[0048]

[0049]

[0050] S6. After the profile is bent in step 5, cut and arrange it to make finished product 1.

[0051] The excess material at both ends of the part is removed by a saw, with a total excess material of 1000mm. At this point, the part is rolled into a semicircle with a diameter of Φ3350mm.

[0052] like Figure 2 As shown, the blank 2 cut from the base material is an L-shaped profile. The cross-section of the first side 21 of the base material is a trapezoidal or triangular structure, and the cross-section of the second side 22 of the base material is a rectangular structure.

[0053] This invention employs a process flow of straight material quenching, straightening, artificial aging, and then roll bending. By rationally designing the roll bending process parameters and using left and right rollers with varying lateral thrust values ​​(at different ratios), along with increased rotation values ​​on both rollers, the invention produces dimensionally qualified parts. The DQ5360 right-angle profile frame with tapered corners, formed using this method, allows for roller-based adjustments to the curvature, flatness, and angular gaps of the formed parts, eliminating the need for manual finishing and significantly reducing worker workload. This process of straight material quenching, straightening, artificial aging, and finally roll bending solves the problem of surface deformation after manual aging following profile bending, and eliminates the low production efficiency associated with subsequent bending and finishing processes after quenching. This invention greatly improves production efficiency and shortens the production cycle. Through the rational design of the roll bending process parameters, dimensionally qualified right-angle profile frame parts with tapered corners are produced through roll bending.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for rolling rigid materials of right-angle profile frames with tapered corners for aerospace applications, characterized in that: Includes the following steps: S1. Cut the blank material to be rolled and bent from the base material according to the requirements (2); S2. Quenching treatment is performed on the blank material (2) to be bent; S3. Straighten the material (2) to be bent; S4. Artificially age the material obtained in step 3 to remove its internal stress; S5. Perform a bending process on the material obtained in step 4. S6. Cut and arrange the profile after the bending process in step 5 to make the finished product (1). The rolling bending equipment in step 5 is a four-axis rolling bending machine. The four-axis rolling bending machine includes a left roller (5), a right roller (6), an upper roller (3) and a lower roller (4) installed on the main frame. The upper roller (3) is located above the lower roller (4). The left roller (5) and the right roller (6) are located on both sides of the upper roller (3). The lower roller (4) and the upper roller (3) are both active rollers. The left roller (5) and the right roller (6) are both driven rollers. The outer periphery of the material (2) is located above the left roller (5), between the upper roller (3) and the lower roller (4) and above the right roller (6) in sequence. The outer periphery of the material (2) is in contact with the outer periphery of the left roller (5), the outer periphery of the upper roller (3), the outer periphery of the lower roller (4) and the outer periphery of the right roller (6) in sequence. The left roller (5) and the right roller (6) push the blank (2) upwards respectively, so that the radius of the blank (2) is reduced. The left roller (5) and the right roller (6) push the blank (2) laterally respectively. The lateral push is an axial movement. The lateral push can prevent the blank (2) from twisting during the rolling process. The left roller (5) and the right roller (6) are respectively provided with rotation values. The rotation values ​​can correct the angle of the first side (21) of the blank (2). The rotation values ​​of the left roller (5) and the right roller (6) are the same. The upper roller (3) can slide vertically. The upper roller (3) presses the blank (2) profile downwards.

2. The method for rolling a rigid material frame with right angle and tapered corner for aerospace applications according to claim 1, characterized in that: The base material is an L-shaped profile. The cross-section of the first side (21) of the base material is a trapezoidal or triangular structure, and the cross-section of the second side (22) of the base material is a rectangular structure.

3. The method for rolling a rigid material frame with right angle and tapered corner for aerospace applications according to claim 1, characterized in that: The quenching temperature in step S2 is 475±5℃, and the quenching holding time is 35~38min. After quenching, the raw material (2) is cooled by water.

4. The method for rolling a rigid material for aerospace right-angle profile with tapered corners according to claim 1, characterized in that: The straightening process in step S3 involves inserting both ends of the raw material (2) into the jaws of the bending machine, setting the bending force of the bending machine to 13t and the stretching amount to 5mm.

5. The method for rolling a rigid material for aerospace right-angle profile with tapered corners according to claim 1, characterized in that: The artificial aging method in step S4 is to heat and keep the raw material (2) at an aging temperature of 120±5℃ for 3 hours, then adjust the aging temperature to 160±5℃ for 3 hours, and then allow it to cool naturally.

6. The method for rolling a rigid material frame with right angle and tapered corner for aerospace applications according to claim 1, characterized in that: The outer periphery of the upper roller (3) is used to position the first edge (21) of the base material.

7. The method for rolling a rigid material frame with right angle and tapered corner for aerospace applications according to claim 1, characterized in that: The lower roller (4) is provided with a first annular mold groove on its periphery, and the first annular mold groove is used to position the first side (21) and the second side (22) of the base material, and the cross-section of the first annular mold groove is the same as the cross-section of the first side (21) and the second side (22) of the base material.

8. The method for rolling a rigid material frame with right angle and tapered corner for aerospace applications according to claim 1, characterized in that: The method for performing the roll bending process in step 4 is as follows: the raw material (2) profile is rolled and formed multiple times on a four-axis roll bending machine, and each time the roll bending is performed, the side push value of the left roller (5) and the right roller (6) is increased, and the side push value of the left roller (5) is greater than the side push value of the right roller (6). The side push value of the left roller (5) gradually increases with each roll bending, and the side push value of the right roller (6) gradually increases with each roll bending. The rotation value of the left roller (5) and the right roller (6) is increased, and the rotation values ​​of the left roller (5) and the right roller (6) are the same. The upward push value of the left roller (5) and the right roller (6) is the same for each roll bending or decreases with each roll bending.

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