CN108380736B

CN108380736B - device for vacuum creep age forming of aluminum alloy member with complex curvature

Info

Publication number: CN108380736B
Application number: CN201810403790.6A
Authority: CN
Inventors: 湛利华; 杨有良; 胡正根; 常志龙; 刘德博; 阮小鹏; 刘观日; 黄诚; 万李
Original assignee: Central South Univ
Current assignee: Central South Univ
Priority date: 2018-04-28
Filing date: 2018-04-28
Publication date: 2020-01-31
Anticipated expiration: 2038-04-28
Also published as: CN108380736A

Abstract

The invention provides a device for vacuum creep age forming of an aluminum alloy member with complex curvature, which comprises a mold surface with complex curvature and a positioning structure arranged on the mold surface, wherein the mold surface is provided with a through hole, the positioning structure comprises a fixed block correspondingly welded in the through hole and a cylindrical positioning column arranged in the fixed block, the fixed block is provided with a cylindrical blind hole for inserting the positioning column, the material strength of the positioning structure is greater than that of the mold surface, and the peripheral area of a forming raw material aluminum alloy plate is provided with two waist-shaped through holes respectively used for inserting the two positioning columns.

Description

device for vacuum creep age forming of aluminum alloy member with complex curvature

Technical Field

The invention relates to the technical field of precise forming and manufacturing of large-scale thin-wall aluminum alloy components with complex curvatures, in particular to a vacuum creep aging forming device for large-scale thin-wall components with complex curvatures and high forming stress characteristics for aerospace.

Background

The method comprises the steps of preparing novel sheet metal forming methods developed for achieving accurate forming and high-performance forming collaborative manufacturing of large-scale integral high-strength aluminum alloy components for aerospace, wherein the methods have the advantages of high forming accuracy, low cost, high repetition rate, low residual stress and the like, the method is mainly applied to forming and manufacturing of components with characteristics of small curvature and low forming stress, such as an upper skin of an airplane wing, the components have large curvature radius, the forming die profile is flat and smooth in overall change, the components cannot move greatly during air pressure loading, a target area on the die profile can be covered after film pasting, the components have large curvature and high forming stress in creep age forming of the large-scale aluminum alloy components, the curvature difference at different positions on the die profile is large, the die profile is concave overall, the components can move greatly during air pressure loading and cannot completely fit the target area, the components can be accurately positioned to fit the target area during bending loading of the components, and finally manufactured components meeting the precision requirements of the aluminum alloy components are manufactured by performing single-pass stress hardening processing on the aluminum alloy components under vacuum stress loading, wherein the steps of the small-aging process, the components can only be prepared by the method in the existing method, the method can only prepare small air pressure, the components can not move greatly, the components when the components are manufactured by performing single-pass aging process, the vacuum stress aging process, the vacuum stress of the vacuum forming process is carried out aging process, the vacuum stress of the aluminum alloy components, the vacuum forming process of the vacuum stress of the vacuum forming process of the vacuum forming method comprises the vacuum forming process of the vacuum forming process, the vacuum forming process of the aluminum alloy components.

Disclosure of Invention

The invention provides forming devices with accurate positioning function aiming at creep age forming of large-scale aluminum alloy components with complex large curvature and high forming stress.

The device for vacuum creep age forming of the aluminum alloy member with the complex curvature comprises a mold surface with the complex curvature and a positioning structure arranged on the mold surface, wherein a through hole is formed in the mold surface, the positioning structure comprises a fixing block and a cylindrical positioning column, the fixing block is correspondingly welded in the through hole, the cylindrical positioning column is arranged in the fixing block, a cylindrical blind hole used for being inserted into the positioning column is formed in the fixing block, the material strength of the positioning structure is larger than that of the mold surface, two waist-shaped through holes are formed in the peripheral area of an aluminum alloy plate serving as a forming raw material, the waist-shaped through holes are formed in the outer side of the periphery of an aluminum alloy member product, the aluminum alloy plate is subjected to vacuum and hot press forming and then is cut to remove the part with the waist-shaped through holes to obtain the aluminum alloy member with the target size and the target curvature, and positioning columns are inserted into the two waist-shaped through holes to position a .

Specifically, the material of the mold surface is, for example, Q235 steel, and the material of the fixing block and the positioning column is high chrome steel or 45 steel.

In the invention, the positioning column is not welded on the fixed block but is tightly inserted into a blind hole of the fixed block so as to timely replace a new positioning column when the positioning column is bent or ground.

In specific embodiments, the weld between the fixing block and the through hole on the mold surface is a hermetic weld.

In specific embodiments, the diameter of the positioning column is 10-50 mm, preferably 20-40 mm, and the total height of the positioning column is 30-200 mm, preferably 100-160 mm.

In specific embodiments, the through holes on the fixing block and the mold surface are both circular or both square, the diameter of the fixing block is 40-80 mm when the fixing block is circular, the thickness of the fixing block is more than two times, preferably more than three times, the diameter of the fixing block is 30mm, the height of the fixing block is 135-145 mm, the diameter of the fixing block is 60mm, the thickness of the fixing block is 80-100 mm, the thickness of the mold surface is 15-20 mm, and the lower end face of the fixing block is below the mold surface.

In preferred embodiments, the top of the positioning post is provided with a threaded blind hole or is provided with an external thread, and the device further comprises a puller with a threaded structure for timely pulling out and replacing the positioning post.

In specific embodiments, the kidney shaped through holes are each ends wide and another ends narrow.

In a specific embodiment, the end with the wide waist-shaped through hole is an arc with the radius of 30mm, the circle center of the arc is 70mm away from the end part of the aluminum alloy plate, the end with the narrow waist-shaped through hole is an arc with the radius of 25mm, the circle center of the arc is 75mm away from the end part of the aluminum alloy plate, the connecting line of the circle centers of the two ends in the length direction of the waist-shaped through hole can be set to be parallel or not parallel to the line of the end part of the aluminum alloy plate according to the shape of a specific aluminum alloy member, if the circle center of the waist-shaped through hole is too close to the end part of the member, the member is easy to be pulled out in the creep aging process.

In the specific embodiment of , after the fixture block is welded in the through hole of the die surface, the top surface is free to transition from the curve of the multi-directional curvature of the top surface of the fixture block to the multi-directional curvature of the top surface of the die surface by milling, and in the specific embodiment of , the upper edge and the lower edge of the through hole of the die surface are welded with the upper edge and the lower edge of the fixture block respectively.

In specific embodiments, the depth of the blind hole on the fixing block is 25-50 mm.

Specifically, the depth of the blind hole is 30mm, for example, and the diameter size of the blind hole is matched with the diameter size of the positioning column, for example, a gap of 0.1mm is formed between the blind hole and the positioning column.

In the specific embodiment, the kidney-shaped through holes are arranged at ends of the member in the length direction, two kidney-shaped through holes are respectively arranged at two opposite sides of the member in the width direction, and preferably, the two kidney-shaped through holes are symmetrically arranged.

In specific embodiments, the kidney shaped through holes are each located at the narrower width end of the member.

In specific embodiments, the mold surface 4 is engraved with a target area line 3 corresponding to the aluminum alloy member after forming, the target area line is used for timely adjusting and determining the position of the aluminum alloy plate during the aluminum alloy plate forming process, and the mold surface is also engraved with a positioning line used for determining the placing position of the aluminum alloy plate before forming.

In creep age forming process, if the aluminum alloy plate is bent and deformed downwards, the periphery of the aluminum alloy is far away from side of a target area line and near side, pressure is released, lower aluminum alloy component is moved to be finally attached to the target area, in addition, other positioning lines are used for guiding in the process of gluing (pasting to form a vacuum bag), the glue is about 20mm away from the periphery of the target area line, specifically, the positioning lines comprise two acute-angle short folding angle lines corresponding to end with wider width of the aluminum alloy plate and used for marking the placing positions of two acute angles of the aluminum alloy plate, two folding angle positioning lines can also be arranged at end with narrower width of the aluminum alloy plate, the width and the depth of the target area line and the positioning lines can be 0.1-0.2 mm.

The invention has at least the following beneficial effects that forming tools with accurate positioning function are provided aiming at creep age forming of large-scale components with complex large curvature and high forming stress characteristics, the tools can enable the components to be completely attached to a forming target area on a mould surface, and the accurate manufacturing of the components is realized.

Drawings

FIG. 1 is a schematic view of a creep age forming apparatus for large complex curvature aluminum alloy components.

FIG. 2 is a schematic view showing the chord height formed between the aluminum alloy sheet and the mold surface before forming.

Fig. 3 is a longitudinal sectional view of the positioning structure in the apparatus.

FIG. 4 is a schematic view (including a partial enlarged view) of an aluminum alloy plate and a kidney-shaped through hole matched with the positioning post on the aluminum alloy plate.

FIG. 5 is a schematic structural view of an aluminum alloy member fully conforming to a target area after creep age forming.

In the figure, 1-card board; 2-forklift holes; 3-target area line; 4-mold surface of the mold; 5-a reinforcing structure; 6-a positioning structure; 61-a fixed block; 62-a positioning column; 01-component.

Detailed Description

creep age forming tool for large complex curvature components, as shown in figure 1, mainly includes a mold surface 4, a positioning structure 6, a reinforcing structure 5, a clamping plate 1 and an auxiliary structure, wherein the mold surface is composed of a middle complex curvature forming surface and two end platforms, the complex curvature forming surface is 15-20 mm thick, the forming surface is the final bending and attaching forming surface of the component, the two end platforms are used for attaching a vacuum bag, the positioning structure includes a positioning column and a fixing block, preferably, the positioning structure also includes a positioning line carved on the mold surface, the component is bent downwards and finally attached to the mold and then located in a target area, the reinforcing structure 5 is formed by welding two longitudinal U-shaped steels, the main function is to increase the strength and rigidity of the mold in the lifting and transportation process, the clamping plate 1 is formed by splicing and welding longitudinal and transverse clamping plates, the long welding line contacting the bottom of the clamping plate and the mold surface is welded by adopting a semicircular structure with the radius of 40-50 mm, the welding internal stress is effectively reduced, meanwhile, the hole structure on the clamping plate can ensure smooth heat flow during heating, and the weight.

The molded surface of the creep aging forming tool for the complex curvature member is concave, and after the flat plate member is placed on the mold, the chord height formed between the flat plate and the molded surface of the mold is nearly 1100mm, as shown in fig. 2. And vacuumizing is carried out after the vacuum bag is sealed, the member is gradually bent under the action of vacuum load, and meanwhile, the two ends of the member gradually move towards the middle until the two ends of the member are completely attached to the molded surface of the mold.

In order to enable a component to be finally attached to a target area, positioning structures are designed at the small end ( end with narrower width) of an aluminum alloy plate, so that the small end of the component is fixed and does not move but only the large end of the component moves towards the middle in the loading process, and the component is accurately positioned.

When the aluminum alloy plate is initially placed on a die, two waist-shaped holes at the small end of the component are matched with two positioning columns arranged on the molded surface of the die, so that the positioning in the length direction is realized; and simultaneously, a positioning line of 0.2mm multiplied by 0.2mm (width multiplied by depth) is engraved on the molded surface of the die corresponding to the large end of the component, and the positioning line (in an acute angle shape) corresponds to the placing position of the aluminum alloy flat plate. When the aluminum alloy plate is placed, the position of the large end is aligned to the positioning line, and the positioning in the width direction is realized.

The creep age forming process of the large complex curvature component comprises the steps of firstly, placing an aluminum alloy flat plate on a mold, firstly, accurately positioning in the length direction and the width direction according to the method, secondly, carrying out vacuum bag sealing on the component, gradually attaching the large end of the component to the middle molded surface in the vacuumizing loading process, accurately attaching the component to a forming target area after vacuumizing is finished, as shown in figure 5, finally, pushing the whole device into an autoclave, carrying out creep age, carrying out cooling and depressurization after the experiment is finished, opening a tank , and taking out the formed component after the temperature of the mold is reduced to the room temperature.

It will be apparent to those skilled in the art that many more modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the following claims .

Claims

The utility model provides a a device that is used for complicated camber aluminum alloy member vacuum creep age forming, including mould profile (4) that contain complicated camber and location structure (6) of setting on the mould profile, the through-hole has been seted up on the mould profile, location structure (6) set up including corresponding welding fixed block (61) in the through-hole and cylindrical reference column (62) of setting in fixed block (61), be equipped with on fixed block (61) and be used for inserting the cylindrical blind hole of reference column, just location structure's material strength is greater than the material strength of mould profile (4), set up two waist shape through-holes in the peripheral region of shaping raw and other materials aluminum alloy plate, waist shape through-hole is seted up in the peripheral outside at the aluminum alloy member product, waist shape through-hole sets up end and two waist shape through-holes at component length direction and sets up respectively in the relative both sides of component width direction, and aluminum alloy plate vacuum and hot briquetting back cutting are got rid of the aluminum alloy plate and are got the aluminum alloy member that contains waist shape through-hole and are target size and target curvature, and shaping in-process, each insert reference column so that end location to the.
2. Device according to claim 1, characterized in that the welding between the fixed block and the through hole provided in the mould profile (4) is a gas-tight welding.
3. The device as claimed in claim 1, wherein the diameter of the positioning post is 10-50 mm, and the total height of the positioning post is 30-200 mm.
4. The device as claimed in claim 1, wherein the through holes formed on the fixing block and the mold surface are both circular or both square, the diameter of the fixing block is 40-80 mm when the fixing block is circular, and the thickness of the fixing block is more than twice of the thickness of the mold surface.
5. The device of claim 1, wherein the kidney-shaped through holes are wide at each end and narrow at each end.
6. The apparatus of claim 1, wherein the fixture block is welded in the through hole of the die surface and milled so that the multi-directional curvature of the top surface of the fixture block is equal to the multi-directional curvature of the top surface of the die surface, and the top surface curves freely.
7. The device as claimed in claim 1, wherein the depth of the blind hole on the fixing block is 25-50 mm.
8. The device of claim 1, wherein the two kidney-shaped through holes are symmetrically disposed.
9. The device of claim 8, wherein the kidney shaped through holes are each disposed at the narrow end of the member.
10. The device according to any of claims 1-9, wherein the mold surface (4) is engraved with a target area line (3) for matching and corresponding to the aluminum alloy member after forming, the target area line is used for timely adjusting and determining the position of the aluminum alloy plate during the forming process of the aluminum alloy plate, and the mold surface is further engraved with a positioning line for determining the placement position of the aluminum alloy plate before forming.