Roll bending correction method for quenched sheet n-shaped frame type part for spaceflight

Abstract

The invention belongs to the technical field of plate frames for spaceflight, and particularly relates to a roll bending correction method for a quenched sheet n-shaped frame part for spaceflight, which comprises the following steps: S1, quenching in a linear state; s2, quenching deformation is eliminated, and the geometric dimension is corrected; s3, roll bending and roll correction correction and forming correction are carried out; s4, flatly knocking the sunken part and rolling a small radian; and S5, performing pure manual accurate correction, and detecting and correcting the 90-degree angle of each bent angle part to enable the 90-degree angle of each bent angle part to meet the angle tolerance requirement. The problems of low processing efficiency, high cost, high correction difficulty and the like caused by the defects of distortion, warping, verticality inclination and vertical plate arching deformation are effectively eliminated, and meanwhile, the correction efficiency is improved by nearly 10 times.

Description

Technical Field

[0001] The invention belongs to the technical field of aerospace sheet frames, and in particular relates to a method for correcting the rolling of aerospace thin plate "X"-shaped frame parts after quenching. Background Art

[0002] Frame parts are structural parts of the rocket body. Together with stringers, skins and other parts, they form the rocket body and are one of the important radial load-bearing parts.

[0003] The cross-section is mostly "J"-shaped and is processed from plates. The commonly used materials are LC9-M super-hard aluminum alloy or LY12-M hard aluminum alloy. The material specifications are 2mm, 2.5mm, and 3.0mm. They are widely used in aerospace products. The maximum arc radius of such parts is about R2000mm, most of the arcs are 180 degrees, and the arc length is greater than 4 meters. Since the parts have high requirements for form and position tolerances, the surface accuracy, flatness, and verticality of the parts will interfere with the normal assembly of the section and may cause it to exceed the tolerance. The accuracy of the parts is crucial to the final product size of the section.

[0004] For testing the curvature surface accuracy, flatness, verticality and vertical straightness of frame parts, the method commonly adopted in the industry is to place the parts on a large circular platform, use a standard curvature template with a length of 1 / 2 of the total length of the part to test the surface accuracy, use the gap with the platform to test the flatness, use the gap with a square to test the verticality, and use the gap with a ruler to test the vertical straightness of the vertical. All form and position tolerances must meet relevant technical requirements.

[0005] With the vigorous development of commercial aerospace in my country, in order to control the overall mass of the rocket and achieve the goal of weight reduction, all rocket body components are being improved in the direction of lightness, thinness and size. Commercial aerospace has designed a new type of plate frame parts with a material thickness of 1.5mm. During the production and processing process, due to the thinning of the material thickness, the reinforcing ribs become shorter, and the commonly used thickness is generally 25-30mm, but now it is only about 10mm. The width of the web becomes shorter, and the commonly used width is generally 90-100mm, but now it is only about 50mm. The vertical plate becomes wider, and the commonly used width is generally 50-60mm, but now it is about 120mm, resulting in a low overall structural strength of the parts. Figure 2 Figure 3 As shown, the overall stress deformation cannot be effectively controlled, and traditional manual correction tools cannot find the right focus point on the parts. In addition, the widening of the vertical plate increases the flat plate area, making the internal stress in the correction process complex and uncertain, making it extremely difficult to roll and correct such thin plates, short ribs, narrow webs, and wide vertical plates after heat treatment and quenching.

[0006] In order to meet the various form and position tolerances of parts, the requirements of curvature and surface accuracy, flatness, verticality, and straightness of parts, and eliminate the distortion, arching, vertical inclination, and arch deformation defects after quenching, it is necessary to repeatedly roll and calibrate on a six-axis rolling mill and perform manual corrections for up to 8 hours. Due to the inability to meet the technical requirements, repeated heat treatment and quenching have to be carried out. The correction is difficult and the efficiency is low, which cannot meet the requirements of the research and development progress of commercial aerospace rockets. The processing problems of this new type of parts have not been effectively solved. Summary of the invention

[0007] The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a method for rolling and correcting thin-plate "J"-shaped frame parts for aerospace after quenching, which solves the problem that the "J"-shaped frame parts with low structural strength for aerospace thin plates are first pre-bent to a curvature slightly larger than the theoretical profile in the traditional processing flow, and then quenched and rolled for correction, which is extremely difficult to correct, and effectively eliminates the problems of high processing efficiency and low cost, and great correction difficulty caused by distortion, warping, vertical tilt, and vertical plate arch deformation defects. At the same time, the correction efficiency is increased by nearly 10 times.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for correcting the rolling bend of thin-plate "X"-shaped frame parts for aerospace after quenching, comprising the following steps:

[0010] S1, straight line state quenching;

[0011] S2, eliminate quenching deformation and correct geometric dimensions;

[0012] S3, rolling correction and forming correction;

[0013] S4, flatten the depression and roll the small arc;

[0014] S5. Manual precision correction, detection and correction of the 90° angle of each corner to meet the angle tolerance requirements.

[0015] Preferably, S2 specifically includes the following steps:

[0016] S21. Install rollers that match the geometric shape and size of the parts on the six-axis rolling bed, adjust the gap between the wheels, and prepare lubricating oil for use during rolling calibration;

[0017] S22. Adjust the positions of the main wheel and the guide wheels on both sides of the six-axis roller bed to the straight line state of the parts, start the roller bed, and push the parts quenched by S1 heat treatment from the guide wheel on one side into the six-axis roller bed to complete the correction of the more serious heat treatment quenching and bundling deformation, so that the geometric cross-sectional dimensions of the parts return to normal.

[0018] Preferably, in S21, the roller gap is 1.5 mm.

[0019] Preferably, S3 specifically includes the following steps:

[0020] S31, Rolling and correction: adjust the relative position of the guide wheels and main wheels on both sides of the six-axis rolling bed in the rolling direction, and gradually roll and correct the parts several times until the arc of the parts is rolled to a value greater than the gap of the template by 6 to 8 mm, then stop rolling;

[0021] S32, forming correction: place the parts on the platform and use the testing gauge to test the straightness, verticality and flatness of the part vertical plate;

[0022] Straightness of the vertical plate: First, manually correct the curved parts of the vertical plate of the entire part, and use a bakelite hammer or a wooden hammer to directly hit the curved parts to meet the technical requirements of straightness;

[0023] Verticality: Use a square to check the verticality of the vertical plate surface of the part placed on the platform and the platform; when there is a gap in the upper part and the curvature of the upper web is greater than that of the lower web, use a bakelite hammer to tap the reinforcing ribs at the upper web with the end facing upwards; when there is a gap in the lower part and the curvature of the lower web is greater than that of the upper web, use a bakelite hammer to tap the reinforcing ribs at the lower web with the end facing upwards; until the verticality meets the technical requirements;

[0024] Flatness: If the entire part is reinforced with vertical ribs placed on the platform and there is an upward arch bridge in some part that fails to fit the platform, a wooden pad should be placed under the vertical ribs at the arch bridge position and hammered down directly until the gap with the platform meets the technical requirements. The flatness of both the upper and lower surfaces needs to be corrected.

[0025] Preferably, in S31, the relative positions of the guide wheels and the main wheels on both sides of the six-axis roller bed are adjusted in the rolling direction, and the position change is 2 to 3 mm each time.

[0026] Preferably, the verticality correction also includes the case where there is no obvious difference in the curvature of the upper and lower webs of the entire part, but the verticality cannot meet the requirements, and the web with a shorter length needs to be shaped until the technical requirements are met.

[0027] Preferably, S4 specifically includes:

[0028] S41, continue to roll the parts that have been corrected by manual tapping, keep the guide wheels on both sides of the six-axis rolling bed in the initial rolling state, turn on the equipment and put the parts in to perform a rolling correction by tapping the concave part with a flat hammer;

[0029] S42. After completing one flatness correction, adjust the relative positions of the two side guide wheels and the main wheel in the direction of reducing the roll. Through several gradual roll bending corrections, keep the upper and lower webs consistent during the process. Stop the roll correction when the part curvature is reduced to be 1-2 mm greater than the template gap.

[0030] A method for roll bending and correction after quenching of a thin plate U-shaped frame part for aerospace use according to claim 7, characterized in that in S42, the position change each time is 1 mm, and it is necessary to place it on the platform to detect the curvature and perpendicularity changes each time. If the local perpendicularity gap becomes larger, local opposite rib knocking still needs to be carried out according to the steps of S3.

[0031] The present invention has the following advantages:

[0032] (1) The present invention cancels the pre-bending process before quenching of the traditional plate frame, quenches in a straight state, and then performs roll bending forming. Through repeated adjustments of reducing and enlarging the roll, the internal stress of the part is evenly released. Combined with manual knocking and web extrusion forming of local uneven positions during the roll correction process, the correction and shaping work can be quickly completed. Effectively eliminate defects such as distortion, arching, perpendicularity inclination, and vertical plate arching. This method has the advantages of simple principle and strong applicability.

[0033] (2) The correction method provided by the present invention effectively eliminates defects such as distortion, arching, perpendicularity inclination, and vertical plate arching deformation. Except for the case of repeated solution heat treatment and quenching, the efficiency is improved and the production and manufacturing cost is reduced. The parts formed by this method have few surface hammer marks and a high qualification rate. In the past, it took 7-8 hours to process one product after heat treatment, and now it only takes about 50 minutes, and the production efficiency is increased by nearly 10 times. Description of the Drawings

[0034] Figure 1 is a schematic diagram of a 180° frame and local parts;

[0035] Figure 2 is a cross-sectional view of a traditional common U-shaped frame;

[0036] Figure 3 is a cross-sectional view of a new U-shaped frame;

[0037] Figure 4 is a schematic diagram of the forming principle of a six-axis rolling machine;

[0038] Figure 5 is a schematic diagram of the straight state of the present invention;

[0039] Figure 6 is a schematic diagram of the correction of the arched part of the present invention;

[0040] Figure 7 is a schematic diagram of the perpendicularity detection state of the present invention;

[0041] Figure 8 It is a schematic diagram of the verticality correction method of the present invention;

[0042] Fig. 9 It is a schematic diagram of the verticality detection state of the present invention;

[0043] Fig.10 It is a schematic diagram of the verticality correction method of the present invention;

[0044] Fig.11 It is a schematic diagram of the hand wheel plate of the fixing frame for fastening the main wheel of the six-axis roller bed of the present invention;

[0045] Fig.12 It is a schematic diagram of flatness correction of the present invention;

[0046] Fig.13 It is a schematic diagram of the tool of the present invention. DETAILED DESCRIPTION

[0047] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0048] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0049] The present invention provides a method for correcting the rolling bend of aerospace thin plate "X"-shaped frame parts after quenching, comprising the following steps:

[0050] S1, straight state quenching; cancel the pre-bending process before quenching, and use the straight state for quenching, that is, before quenching the parts, just use the bending equipment to process the cross-section size of the letter "J", without pre-bending. Figure 5 shown.

[0051] Traditional parts forming all use the rolling bed to pre-bend the curvature of the profile to a certain size slightly larger than the theoretical profile, and then perform rolling correction after heat treatment and quenching. The traditional process method has small quenching deformation and very good forming effect for conventional thickness plates and parts with good structural dimensions. However, for such parts with a thickness of 1.5mm and low strength, if they are pre-bent before quenching, due to the large quenching deformation, there is a lack of sufficient rolling correction range after the parts are quenched. Because the curvature of the profile is basically in place, the material fluidity during the rolling correction process is insufficient, and the internal stress rolling correction adjustment amount is small, it is impossible to effectively eliminate the problems of distortion, arching, vertical tilt and other defects. If rolling is used after quenching, a sufficient rolling correction adjustment range can be obtained. At this time, the parts are in a straight line state, so that the material structure is fully and evenly extended, the internal stress is effectively eliminated, and it becomes easier to make rolling corrections to meet technical requirements.

[0052] S2, eliminate quenching deformation and correct geometric dimensions;

[0053] S21. Install rollers that match the geometric shape and size of the parts on the six-axis rolling bed, and adjust the gap between each wheel. The gap is consistent with the thickness of the part material, that is, 1.5mm. It is important that the gap meets the requirements. If the gap is too small, the material thickness will become thinner, and the organization will become irregular and loose, making correction difficult. If the gap is too large, the geometric cross-sectional dimensions and bending angles of the parts after quenching cannot be properly extruded and corrected, making the parts irregular and affecting the accuracy of various shape and position tolerances. Prepare lubricating oil for use during rolling correction;

[0054] S22. Adjust the position of the main wheel and the guide wheels on both sides of the six-axis roller bed to the straight line state of the parts, that is, the position difference between the guide wheels on both sides and the main wheel is at 0. Turn on the roller bed, push the parts that have just been heat treated and quenched into the six-axis roller bed from the guide wheel on one side to complete the correction of the more serious heat treatment quenching and bundling deformation, so that the geometric cross-sectional dimensions of the parts return to normal. This operation only needs to be performed once.

[0055] S3, rolling correction and forming correction;

[0056] S31. Rolling: After the straight-line parts have completed the quenching and bundling deformation correction, they can be rolled and corrected. Adjust the relative position of the guide wheels and the main wheels on both sides of the six-axis rolling bed in the rolling direction. Note that the position change is 2 to 3 mm each time, and it should not be too hasty. If the size is adjusted too large at one time, the parts will have uneven bulges and be difficult to eliminate. After several gradual rolling and corrections, the curvature of the parts is rolled to a curvature greater than the template gap of 6 to 8 mm, and then the rolling is stopped. Note that each time the part enters the rolling bed, the part needs to be turned over. The purpose of turning over is to minimize the difference in the curvature of the upper and lower webs. If one side is always kept entering the equipment, there will be a significant difference in the curvature of the upper and lower webs, so frequent turning over is required for rolling correction. This is mainly due to the small gap difference between the upper and lower ends of the main shaft in the structure of the six-axis rolling bed equipment.

[0057] S32, straightness, perpendicularity and flatness defect correction;

[0058] Place the parts on the platform and use the inspection gauge to inspect the straightness, verticality and flatness of the parts' vertical plates.

[0059] Straightness of vertical plate: First, manually correct the arched parts of the vertical plate of the whole part, such as Figure 6 , use a bakelite hammer or a wooden hammer to directly hit the arched part to achieve the technical requirements of straightness.

[0060] Verticality: Use a square to check the verticality of the vertical plate surface of the part placed on the platform and the platform. If there is a gap on the upper part and the curvature of the upper web is greater than that of the lower web, two people will lift the part, with the end facing up, and use a bakelite hammer to knock on the reinforcement ribs at the upper web. Figure 7 , Figure 8 .

[0061] If there is a gap at the bottom and the curvature of the lower web is greater than that of the upper web, two people will lift the end of the part upward and use a bakelite hammer to hit the reinforcement ribs at the lower web. Fig. 9 , Fig.10 Until the verticality meets the technical requirements, the verticality of the entire part needs to be checked and corrected. Note that when correcting the verticality, the curvature of the upper and lower webs must be controlled, because knocking will make the curvature smaller. Try to avoid a large difference in the curvature of the upper and lower webs, and the gap difference can be controlled within 1 to 2 mm.

[0062] Another situation of verticality is that there is no obvious difference in the curvature of the upper and lower webs of the entire part, but the verticality cannot meet the requirements. This is because the overall part is not level and there is an overall upward tilt, that is, the lengths of the upper and lower webs are inconsistent. We need to shape the shorter web. In this case, if there is a gap on the upper part of the square during inspection, it means that the upper web is short, and if there is a gap on the lower part of the square, it means that the lower web is short. You only need to adjust the handwheel of the fixed frame on the two main wheels of the six-axis roller bed in the tightening direction by less than 1 / 8 of a turn, such as Fig.11 . That is to say, make the upper and lower gaps between the two main wheels inconsistent, and make the upper gap smaller, but it should be noted that it should not be adjusted too much and can only be adjusted less than 1 / 8 circle. The pitch of the handwheel adjustment of different rolling bed equipment may be different. The gap adjustment amount should be controlled between 0.05 and 0.10mm. Too much will make the thickness of the part too thin, and the shape cannot be controlled and scrapped. The adjustment amount of different equipment is different and needs to be carried out according to the specific situation. The principle is to ensure that the overall thickness of the part is within the tolerance range. Then put the short side of the web at the position where the gap between the two main wheels is small for rolling correction and shaping. The shaping distance is based on the actual situation. It can be rolled multiple times but the fixed frame wheel disc cannot be tightened again. Each time, the verticality change needs to be detected. It meets the requirements. Note that the fixed frame wheel disc must be restored to its original position after the shaping is completed to prevent misoperation during subsequent rolling correction.

[0063] Flatness: refers to the gap between the reinforcement ribs and the platform of the entire part. If there is an upward arch bridge at a local position when placed on the platform and it fails to fit the platform, a wooden pad should be placed under the ribs at the arch bridge position and hammered down directly until the gap with the platform meets the technical requirements, such as Fig.12 The flatness of both the upper and lower surfaces needs to be corrected.

[0064] S4, flatten the depression and roll the small arc;

[0065] S41. Continue to roll the parts that have been corrected by manual tapping. Keep the guide wheels on both sides of the six-axis rolling machine in the initial rolling state. Turn on the equipment and put the parts in to perform a rolling correction by tapping the concave part with a flat hammer.

[0066] S42. After completing a leveling correction, adjust the relative position of the guide wheels on both sides and the main wheels in the rolling direction. Note that each adjustment position changes by 1mm. Each time, it is necessary to place it on the platform to detect the changes in curvature and verticality. If the local verticality gap becomes larger, it is still necessary to perform local tapping of the ribs according to the method in the third step. At this time, it has entered the stage of precise rolling correction. Through several gradual rolling corrections, attention should be paid to each flipping of the part. During the process, the upper and lower belly plates must be controlled to keep the same as much as possible. Stop rolling correction when the curvature of the part is rolled to a size larger than the template gap by 1 to 2mm. A slightly larger size is conducive to subsequent pure manual correction. The curvature will become smaller during the manual finishing stage.

[0067] If the curvature of the part is smaller than the theoretical curvature during the rolling process, the relative position of the guide wheels and the main wheels on both sides of the six-axis roller bed can be adjusted to the appropriate position in the direction of enlarging. It is also necessary to pay attention to the position change of 2 to 3 mm each time, and gradually enlarge the correction through several times. It should be noted that each time the part is turned over, the curvature of the part should be enlarged to 1 to 2 mm larger than the template gap.

[0068] S5, manual precision correction, after the first four steps of rolling correction, the parts are in the best condition, and the flatness, verticality, and straightness correction processes are basically completed. It is only necessary to detect and correct the 90° angle of each corner to meet the angle tolerance requirements. With the completion of the angle correction, the arc basically meets the technical requirements, and the entire post-quenching rolling correction is completed.

[0069] The equipment used in the present invention is a six-axis rolling bed, common detection measuring tools and common tools for manual correction of sheet metal, such as bakelite hammers, aluminum hammers, wooden pads, correction tires (correction rings), and arc detection templates. The specific structure is as follows Fig.13 As shown. After the rolling correction of the first four steps of this technical solution, the parts are in the best state, and the flatness, verticality and straightness correction processes have basically been completed. In the fifth step, the traditional cold sheet metal manual forming tools are used in conjunction with the tire mold to correct the angle, and the shape correction process can be completed easily and quickly. The specific correction method selected is a common method in the sheet metal industry and will not be described here.

[0070] The present invention is not limited to the aforementioned specific embodiments. The present invention extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed. Those of ordinary skill in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments.

[0071] A person skilled in the art may, based on the technical teachings disclosed in the present invention, make various other specific modifications and combinations without departing from the essence of the present invention, and these modifications and combinations are still within the protection scope of the present invention.

Claims

1. A method for correcting the rolling bend of thin-plate "X"-shaped frame parts for aerospace after quenching, characterized in that: The following steps are involved: S1, straight line state quenching; S2, eliminate quenching deformation and correct geometric dimensions; S3, rolling correction and forming correction; S4, flatten the depression and roll the small arc; S5. Manual precision correction, detection and correction of the 90° angle of each corner to meet the angle tolerance requirements.

2. The method for correcting the rolling bend of thin-plate "X"-shaped frame parts for aerospace after quenching according to claim 1 is characterized in that: S2 specifically includes the following steps: S21. Install rollers that match the geometric shape and size of the parts on the six-axis rolling bed, adjust the gap between the wheels, and prepare lubricating oil for use during rolling calibration; S22. Adjust the positions of the main wheel and the guide wheels on both sides of the six-axis roller bed to the straight line state of the parts, start the roller bed, and push the parts quenched by S1 heat treatment from the guide wheel on one side into the six-axis roller bed to complete the correction of the more serious heat treatment quenching and bundling deformation, so that the geometric cross-sectional dimensions of the parts return to normal.

3. The method for correcting the rolling bend of thin-plate "X"-shaped frame parts for aerospace after quenching according to claim 2 is characterized in that: In S21, the roller gap is 1.5 mm.

4. The method for correcting the rolling bend of thin-plate "X"-shaped frame parts for aerospace after quenching according to claim 1 is characterized in that: S3 specifically includes the following steps: S31, Rolling and correction: adjust the relative position of the guide wheels and main wheels on both sides of the six-axis rolling bed in the rolling direction, and gradually roll and correct the parts several times until the arc of the parts is rolled to a value greater than the gap of the template by 6 to 8 mm, then stop rolling; S32, forming correction: place the parts on the platform and use the testing gauge to test the straightness, verticality and flatness of the part vertical plate; Straightness of the vertical plate: First, manually correct the curved parts of the vertical plate of the entire part, and use a bakelite hammer or a wooden hammer to directly hit the curved parts to meet the technical requirements of straightness; Verticality: Use a square to check the verticality of the vertical plate surface of the part placed on the platform and the platform; when there is a gap in the upper part and the curvature of the upper web is greater than that of the lower web, use a bakelite hammer to tap the reinforcing ribs at the upper web with the end facing upwards; when there is a gap in the lower part and the curvature of the lower web is greater than that of the upper web, use a bakelite hammer to tap the reinforcing ribs at the lower web with the end facing upwards; until the verticality meets the technical requirements; Flatness: If the entire part is reinforced with vertical ribs placed on the platform and there is an upward arch bridge in some part that fails to fit the platform, a wooden pad should be placed under the vertical ribs at the arch bridge position and hammered down directly until the gap with the platform meets the technical requirements. The flatness of both the upper and lower surfaces needs to be corrected.

5. The method for correcting the rolling bend of thin-plate "X"-shaped frame parts for aerospace after quenching according to claim 4 is characterized in that: In S31, the relative positions of the guide wheels and the main wheels on both sides of the six-axis roller bed are adjusted in the rolling direction, and the position change is 2 to 3 mm each time.

6. The method for correcting the rolling bend of thin-plate "X"-shaped frame parts for aerospace after quenching according to claim 4 is characterized in that: Verticality correction also includes when there is no obvious difference in the curvature of the upper and lower webs of the entire part, but the verticality cannot meet the requirements, in which case the shorter web needs to be shaped until it meets the technical requirements.

7. The method for correcting the rolling bend of thin-plate "X"-shaped frame parts for aerospace after quenching according to claim 1 is characterized in that: S4 specifically includes: S41, continue to roll the parts that have been corrected by manual tapping, keep the guide wheels on both sides of the six-axis rolling bed in the initial rolling state, turn on the equipment and put the parts in to perform a rolling correction by tapping the concave part with a flat hammer; S42. After completing a leveling correction, adjust the relative position of the guide wheels on both sides and the main wheels in the rolling direction, and perform gradual rolling corrections several times. During the process, keep the upper and lower belly plates consistent. Stop rolling correction when the curvature of the part is rolled down to a size 1 to 2 mm larger than the template gap.

8. The method for correcting the rolling bend of thin-plate "X"-shaped frame parts for aerospace after quenching according to claim 7 is characterized in that: In S42, the position change is 1mm each time, and each time it is necessary to place it on the platform to detect the changes in curvature and verticality. If the local verticality gap becomes larger, it is still necessary to perform local tapping on the opposite ribs according to step S3.

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