CN110508653B

CN110508653B - Roll forming method of rib plate

Info

Publication number: CN110508653B
Application number: CN201910653074.8A
Authority: CN
Inventors: 温彤; 潘有成; 游建豪; 周银; 唐浩兴
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2019-07-19
Filing date: 2019-07-19
Publication date: 2020-09-29
Anticipated expiration: 2039-07-19
Also published as: CN110508653A

Abstract

The invention provides a roll forming method of a ribbed plate. The method can carry out plastic forming on the flat plate blank under a small load, and has great advantages when forming the rib plate with large size and high strength; the finish machining cutting amount is greatly reduced, the advantages of high plastic forming production efficiency and high material utilization rate can be fully exerted, and the streamline distribution of a workpiece material is reasonable and the mechanical property is good; the lower roller is replaced by a platy lower die, and a fan-shaped roller replaces a complete roller, so that the equipment space is saved; the large-roll-diameter roller is used, so that the width of a deformation area is increased, the buckling deformation is effectively reduced, and the filling property is improved; the lower die has a restraining effect on a formed part, so that extension caused by forward sliding can be reduced to a great extent, and the dimensional accuracy is improved.

Description

Roll forming method of rib plate

Technical Field

The invention relates to the field of material forming.

Background

Ribbed panels are structural parts of the panel shell type with protruding ribs on the panel plane. The member can greatly reduce weight under the condition of meeting the requirements of strong structure and rigidity, and has wide application in the fields of transportation, aerospace, war industry and the like.

At present, the rib plate member forming method mainly comprises the following steps: casting, machining, welding, plastic forming, 3D printing and other methods, but all have the following defects:

1. casting

The cast parts have low strength, poor surface quality and low production efficiency, and are usually only used for producing large thin-web high-rib components with low performance requirements.

2. Machining

The machining process generally adopts forged or rolled slabs, and uses a numerical control machine tool to perform cutting process, but because the metal streamline of the reinforcing rib part is damaged in the cutting process, the mechanical property of the reinforcing rib part is difficult to ensure, and the deformation phenomenon exists. In addition, the mechanical processing has low material utilization rate and high cost.

3. Welding of

The welding method for processing the rib and rib plate type components has low production efficiency, poor adaptability to complex structures, large residual stress of the welding structure, low fatigue strength, and poor structural consistency and reliability.

4. Plastic forming

In common plastic forming methods such as forging, stamping and the like, rib plates cannot be directly obtained due to the reasons of large forming load, difficult deformation control and the like. In order to reduce the load, methods such as local load forming, isothermal forging, rolling, and the like are proposed for plastic forming of rib plates.

(1) Local loading shaping

The local loading has low production efficiency, and is easy to cause local underfilling and poor forming quality.

(2) Isothermal forging

Isothermal forging requires die forging at an extremely low strain rate, production efficiency is low, and operation difficulty of maintaining constant temperature for a long time is high.

(3) Roll pressing

The billet is easily subjected to elongation and buckling deformation during rolling, resulting in low dimensional accuracy. It is difficult to form a high-rib member because of poor filling property.

5.3D printing

The 3D requires expensive forming equipment and raw materials, has high cost and low efficiency, has some limitations in the aspects of mechanical property, surface quality and the like of a finished piece, and is few in types of currently applicable materials.

In summary, the existing methods for machining the rib plate member have respective defects, and are difficult to meet the requirements of production practice, so that research and development of a new method for machining the rib plate member are necessary.

Disclosure of Invention

The invention aims to provide a roll forming method of a ribbed plate, which is characterized by comprising the following steps:

the adopted rolling equipment mainly comprises a main roller and a horizontal lower die. The upper surface of lower mould has the recess that corresponds with the muscle on muscle rib board surface.

When the rolling die works, the main roller and the lower die synchronously move to roll the flat blank.

Further, the main roller is fan-shaped.

Further, the main roller wheel reciprocates along the central axis.

The horizontal lower die reciprocates in the horizontal plane along with the main roller.

Further, the main roller drives the rack fixed on one side of the lower die to move through the gear.

Furthermore, a mandril is arranged in the lower die. And after the rolled flat blank is formed, the ejector rod jacks up the flat blank from the upper surface of the lower die to finish demoulding.

The invention has the following beneficial effects: the method can carry out plastic forming on the flat plate blank under a small load, and has great advantages when forming the rib plate with large size and high strength; the finish machining cutting amount is greatly reduced, the advantages of high plastic forming production efficiency and high material utilization rate can be fully exerted, and the streamline distribution of a workpiece material is reasonable and the mechanical property is good; the lower roller is replaced by a platy lower die, and a fan-shaped roller replaces a complete roller, so that the equipment space is saved; the large-roll-diameter roller is used, so that the width of a deformation area is increased, the buckling deformation is effectively reduced, and the filling property is improved; the lower die has a restraining effect on a formed part, so that extension caused by forward sliding can be reduced to a great extent, and the dimensional accuracy is improved.

Drawings

FIG. 1 is a schematic view of a method for roll forming a ribbed plate according to the present invention;

FIG. 2 is a side view of the flat blank of the present invention prior to roll forming;

FIG. 3 is a side view of a roll forming process of the ribbed board of the present invention;

FIG. 4 is a side view of the ribbed board of the present invention after it has been roll formed;

FIG. 5 is a schematic view of a ribbed panel with grid ribs;

FIG. 6 is a schematic view showing a rolling simulation result of a ribbed plate with network ribs (the excess part of the outer edge is not cut off);

fig. 7 is a comparison graph of load-time curves of the integral forging forming process and the rolling forming process of the ribbed plate with the network ribs obtained by numerical simulation.

In the figure: the device comprises a flat blank (1), a main roller (2), a lower die (3) and a mandril (4).

Detailed Description

The present invention is further illustrated by the following examples, but it should not be construed that the scope of the above-described subject matter is limited to the following examples. Various substitutions and alterations can be made without departing from the technical idea of the invention and the scope of the invention is covered by the present invention according to the common technical knowledge and the conventional means in the field.

Example 1:

a roll forming method of rib plates is characterized in that:

the roll press apparatus used with reference to fig. 1 mainly includes a main roll 2 and a horizontal lower die 3.

It is worth mentioning that the existing rolling equipment causes the rib plate to extend, the extension is caused by forward sliding, and in practice, the forward sliding is difficult to avoid because the outlet end of the roll forging die is not restrained. In this embodiment, a horizontal lower die 3 is used, and referring to fig. 2, the upper surface of the lower die 3 is provided with grooves corresponding to the ribs on the surface of the rib plate. The lower die 3 has a restraining action on the formed portion, thereby suppressing forward slip.

It should be noted that the larger the ratio of the depth to the width of the groove, the greater the difficulty of forming, the more likely to cause kinking of the root of the rib, and also to cause an increase in the area of the rim that is not filled with the material (the lower part of the peripheral rib in fig. 6), and if the ratio is too large, the overall filling will be insufficient. Preferably, the ratios are all less than 4-6.

In the embodiment, it is difficult to form the rib plate when the ratio of the depth of the groove to the thickness of the web (the thinnest portion of the rib plate, i.e., the portion between the ribs) is large. Preferably, the ratios are all less than 5-8.

In operation, the main roller 2 and the lower die 3 move synchronously to roll the sheet blank 1. Namely, the linear velocity of the outer edge of the roller is the same as that of the lower die. In the embodiment, one side of the main roller 2 is fixedly connected with a gear which rotates synchronously. And a rack meshed with the gear is fixed on one side of the lower die 3, and the lower die 3 is driven to reciprocate by the gear. The gear and the rack are matched to ensure that the meshing line is at the outer edge of the roller so as to meet the requirement of synchronous motion.

It is worth mentioning that the prior rolling equipment causes the rib plate to warp because of the difference of the metal flow speed on the upper and lower die parting surfaces of the outlet. In the embodiment, the main roller 2 is fan-shaped, the diameter of the fan-shaped roller is 500-2000 mm, and the angle of the fan-shaped roller is 60-120 degrees. The main roller 2 rotates reciprocally along the central axis. The horizontal lower die 3 reciprocates in the horizontal plane along with the main roller 2.

And a mandril 4 is arranged in the lower die 3. After the rolled flat blank 1 is formed, the ejector rod 4 ejects the flat blank 1 from the upper surface of the lower die 3 to finish demoulding.

Example 2:

the main technical scheme of the embodiment is the same as that of the embodiment 1. I.e. for retrofitting with existing rolling equipment.

The refitting steps are as follows:

dismantling the upper roller, and replacing the upper roller with a main roller 2 described in embodiment 1;

removing the lower roller;

installing a guide rail below the main roller 2, and installing the lower die 3 on the guide rail;

adjusting the positions of the main roller 2 and the guide rail (the lower die 3) to enable the gear on one side of the main roller 2 to be meshed with the rack on one side of the lower die 3, so that the main roller can move synchronously.

And 5, a rotating shaft of the main roller 2 is connected with a power device of the original upper roller. The power device drives the main roller 2 and the gear to do periodic reciprocating rotation (swing).

Example 3:

this example produced a rib plate as shown in fig. 5 (hereinafter, the horizontal direction is the rib plate length and width direction, and the vertical direction is the rib plate thickness direction), the total length, width and thickness (web thickness + maximum rib height) of the rib plate were 500mm, 500mm and 25mm, respectively, the length and width of the mesh to be press-formed were 140mm and 140mm, respectively, the web thickness (thickness is the distance between the bottom of the recess in the middle of the mesh and the other side) was 5mm, the transverse rib depth (the rib height measured in the rib plate vertical direction) was 20mm, the longitudinal rib depth (the rib height measured in the rib plate vertical direction) was 15mm, and the rib thickness (the rib width measured in the rib plate horizontal direction) was 5mm by the method described in example 1.

The blank of the ribbed plate is a 6061 aluminum plate with the density of 2.89g/mm²Poisson's ratio v of 0.33, Young's modulus E of 68900MPa, yield strength σ_sIs 65 MPa.

The method for rolling and forming the ribbed plate comprises the following steps:

(1) analyzing the geometric shape of the rib plate component to be formed, and adding process supplement and machining allowance to the rib plate component according to the characteristics and requirements of plastic forming to obtain a rolling blank drawing of a rib plate;

(2) according to the rolled blank drawing, determining the length, width and thickness of the ribbed slab blank according to the principle that the blank and the workpiece have equal volumes. In the embodiment, the length of the flat plate blank is determined to be 500mm, the width is determined to be 340mm, and the thickness is determined to be 13 mm;

(3) designing a lower die type groove according to the shape of the network-shaped rib, and finishing the processing and manufacturing of the upper die and the lower die; in this embodiment, the radius of the roller is 2000 mm.

(4) Mounting the lower die on a special rolling mill;

(5) running a rolling mill to roll and form the rib plate flat plate blank to obtain a rib plate blank; in this embodiment, the rotational angular velocity of the main roller is 0.01 rad/s.

In the process of rolling forming, the blank positioned on the lower die and the lower die are sent to the inlet side of the roller together, and under the action of the roller and the lower die, the blank is gradually subjected to plastic deformation and is filled into the groove of the lower die.

(6) And after the rolling is finished, the finished piece is demoulded under the action of the lower die ejection device, so that the ribbed plate finished piece with a certain size and shape is obtained.

(7) And cutting off the redundant part of the outer edge of the ribbed plate after the rolling to obtain a ribbed plate workpiece meeting the final requirement.

Experiment:

and (5) carrying out numerical simulation on the integral forging process and the step (5) of the rib plate by using a plastic finite element method to obtain a rib plate rolling forming simulation result diagram shown in figure 6 and a forming load-time curve shown in figure 7. It can be seen from fig. 6 that the ribbed plate obtained by roll forming has good filling performance, no obvious warp deformation and extension, and high dimensional accuracy. As can be seen from fig. 7, the stamping load is increasing and the maximum value exceeds 5 ten thousand tons, while the maximum load of the roll forming is 8 kilotons, and the load is reduced remarkably.

Claims

1. A roll forming method of rib plates is characterized in that:

the adopted rolling equipment mainly comprises a main roller (2) and a horizontal lower die (3); the upper surface of the lower die (3) is provided with grooves corresponding to ribs on the surface of the rib plate;

when the rolling device works, the main roller (2) and the lower die (3) synchronously move to roll the flat blank (1); the main roller (2) is fan-shaped; the main roller (2) rotates along the central shaft in a reciprocating way;

the horizontal lower die (3) reciprocates in the horizontal plane along with the main roller (2).

2. The roll forming method of a ribbed plate according to claim 1, wherein: the main roller (2) drives a rack fixed on one side of the lower die (3) to move through a gear.

3. The roll forming method of a ribbed plate according to claim 1 or 2, wherein: a mandril (4) is arranged in the lower die (3); and after the rolling flat blank (1) is formed, the ejector rod (4) ejects the flat blank (1) from the upper surface of the lower die (3) to finish demoulding.