An electropulse-assisted roll forming apparatus and method for thin metal sheets
By using an electro-pulse assisted roll forming device for thin metal sheets, which utilizes multi-pass roll forming and electro-pulse loading, combined with insulating and heat-resistant cloth, the problems of large deformation resistance and cracking in the forming process of titanium alloy thin sheets are solved, achieving low-energy and high-efficiency forming, which is suitable for the processing of complex components in the aerospace field.
Patent Information
- Application Number
- CN202411921385.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2026-06-26
AI Technical Summary
Existing technologies are difficult to efficiently form thin metal sheets with low density and high specific strength, such as titanium alloy sheets, especially since they have high deformation resistance, low plasticity, and significant residual stress at room temperature. Furthermore, traditional processing methods are energy-intensive, require sophisticated equipment, and are inefficient, making it difficult to meet the forming accuracy and assembly requirements of the aerospace industry.
A metal sheet electric pulse assisted roll forming device is adopted. Through multiple roll forming and electric pulse loading, combined with insulating heat insulation cloth, pulse current is directly applied to the metal sheet for forming. The insulating heat insulation cloth is used to isolate heat conduction and electrical conduction, so as to achieve low energy consumption and high efficiency forming.
It reduces residual stress in sheet metal, improves forming capacity, reduces cracking behavior, lowers energy consumption, and improves forming quality and efficiency. It is suitable for machining long parts, especially thin-walled, deep-cavity complex components.
Smart Images
Figure CN122273989A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metal sheet forming technology, and in particular to an electrical pulse-assisted roll forming apparatus and method for thin metal sheets. Background Technology
[0002] Thin metal sheets, represented by titanium alloys, have attracted widespread attention in the aerospace field due to their advantages such as low density, high specific strength, corrosion resistance, and high temperature resistance. They are often used as protective barriers to prevent structural components of aircraft wings from being affected by harsh environments. However, some thin metal sheets, such as titanium alloy sheets, have high deformation resistance at room temperature, low plasticity, significant residual stress, and narrow processing windows, making it difficult to meet forming accuracy and assembly requirements. Hot stamping is currently the main processing method for these difficult-to-form thin metal sheets. The sheet material is usually heated by traditional methods such as furnace heating, induction heating, resistance heating, and laser heating. Especially for some thin-walled, deep-cavity complex components, whose longitudinal length may reach tens of meters, the use of traditional cutting processes or hot stamping forming technology results in large investments, high equipment requirements, high energy consumption, and low efficiency, which does not meet the needs of future technological development. Therefore, there is an urgent need for an advanced metal sheet forming device that can achieve low-cost, high-efficiency, and high-quality processing. Summary of the Invention
[0003] The purpose of this invention is to provide an electrical pulse-assisted roll forming device and method for thin metal sheets, which has low energy consumption and high efficiency.
[0004] The objective of this invention can be achieved through the following technical solution: a metal sheet electro-pulse assisted roll forming device, comprising a roll forming die, an insulating and heat-insulating component, and an electro-pulse component;
[0005] The roller pressing die includes multiple sets of upper rollers and lower rollers;
[0006] The insulating and heat-insulating component includes an insulating and heat-insulating cloth that can be covered on the surface of a metal sheet by a roll forming die;
[0007] The electrical pulse assembly includes a brush in contact with the metal sheet and a pulse power supply connected to the brush.
[0008] Preferably, the insulating and heat-insulating cloth comprises a high-silica cloth.
[0009] Preferably, the insulating and heat-insulating cloth covers the upper and lower surfaces of the metal sheet.
[0010] Preferably, the insulation and heat insulation assembly further includes an active roller and a driven roller for cooperating with a rolling die to cover the surface of the metal sheet with the insulation and heat insulation cloth.
[0011] Preferably, the metal sheet electropulse assisted roll forming device further includes a forming mold.
[0012] More preferably, along the metal sheet conveying direction, the forming die is positioned after the brush on one side of the roll forming die and the pre-forming outlet.
[0013] More preferably, the shaping mold includes multiple sets of non-electrically powered upper shaping rollers and lower shaping rollers.
[0014] Preferably, along the conveying direction of the metal sheet, the bending angle of the die surface and the width of the rolling surface of the lower roller gradually decrease.
[0015] Preferably, the rotation axes of each upper roller of the rolling die are located on the same horizontal plane, and the lower roller is correspondingly placed below the upper roller. The rotation axes of each set of upper and lower rollers are located on the same vertical plane perpendicular to the horizontal plane.
[0016] More preferably, the upper rollers of the rolling die have the same radius.
[0017] A method for electropulse-assisted roll forming of thin metal sheets, using the aforementioned apparatus.
[0018] Preferably, the method for electro-pulse assisted roll forming of thin metal sheets includes the following steps: pushing the metal sheet into the device along its length, and having it continuously bitten by multiple sets of upper and lower rollers of the roll forming die for pre-forming, while maintaining contact with the brush on one side of the pre-forming feed inlet; starting the pulse power supply; when the pre-formed part contacts the brush on one side of the pre-forming discharge outlet, the metal sheet rapidly reaches the forming temperature under the action of the pulse current; the upper and lower insulating heat insulation cloths of the metal sheet are in a state of free loading on both sides to ensure that they do not break; continuing roll forming under continuous power supply until, after a period of time, the pre-formed part is obtained under the power supply state after all passes are completed; the pre-formed part enters the shaping die for geometric shaping; and finally, the shaped sheet is cut out.
[0019] More preferably, the cross-sectional shape of the formed plate is V-shaped or U-shaped.
[0020] More preferably, the thickness of the formed plate is 0.3 to 2 mm and the length is >1 m.
[0021] More preferably, the formed plate is used for aircraft blades, and more preferably for the leading edge of aircraft blades (to protect the blades).
[0022] More preferably, the peak current of the pulse power supply is ≥15000A, and the current density is 2.0~5.0A / mm². 2 The duty cycle is 20% to 40%.
[0023] More preferably, the thickness of the metal sheet is 0.3 to 2 mm.
[0024] More preferably, the shape of the brush is consistent with the shape of the inlet and outlet of the metal sheet. That is, both the brush on the pre-forming inlet side and the metal sheet are flat structures, and the brush on the pre-forming outlet side has the same shape as the pre-formed part, so as to facilitate the fit of the sheet surface. Through the design of the brush shape, the contact area with the metal sheet can be increased.
[0025] More preferably, the metal sheet material includes titanium alloy or lightweight high-strength steel.
[0026] More preferably, the metal sheet undergoes multiple roll forming processes involving 3 to 30 sets of upper and lower rollers during the roll forming process.
[0027] More preferably, while the metal sheet is being bitten into the first set of upper and lower rollers by the rolling die, an insulating and heat-insulating cloth is covered and adhered to the surface of the metal sheet.
[0028] More preferably, the insulating fabric is peeled off the surface of the formed part as the formed part is fed out from the last set of upper and lower rollers.
[0029] More preferably, the metal sheet undergoes multiple rolling forming processes using 1 to 3 sets of non-electrically powered upper and lower rollers.
[0030] Compared with the prior art, the present invention has the following beneficial effects:
[0031] 1. Compared with traditional stamping processes, this invention reduces residual stress in the sheet metal, improves its formability, and alleviates cracking by using sequentially configured multi-pass roll forming.
[0032] 2. Compared with the traditional electric pulse stamping process applied to rollers, this invention directly applies electric pulses to the metal sheet and performs multi-pass roll forming in a sequential manner, which reduces the residual stress of the sheet, improves the sheet's forming ability, alleviates the sheet's cracking behavior, and allows the sheet length to be adjusted arbitrarily.
[0033] 3. This invention directly applies current to the metal sheet, requiring less energy, resulting in lower energy consumption and higher efficiency. Furthermore, by adding insulating and heat-insulating cloth to the metal sheet, it achieves the purpose of heat preservation and insulation from the rollers, making the power supply safer.
[0034] 4. This invention provides an efficient electrical pulse-assisted roll forming device and method for thin metal sheets. Compared with traditional heating methods, applying pulse current during the deformation process of the sheet reduces the forming resistance of the sheet, improves the mechanical properties and surface quality of the sheet, and has the advantages of low energy consumption and high processing efficiency.
[0035] 5. The present invention comprises an insulating and heat-insulating module consisting of high-silica cloth, a driven roller, and upper and lower rollers. When an external power source powers the sheet material, it can effectively prevent current from being conducted to the rollers, thus avoiding damage to the rolling equipment and improving the utilization rate of the current. On the other hand, the high-silica cloth adheres closely to the surface of the sheet material during the rolling process, suppressing the convective heat transfer between the sheet material and the air, and achieving a beneficial heat preservation effect.
[0036] 6. This invention directly applies current to the metal sheet, which, compared to directly energizing the upper and lower rollers, eliminates the need to heat each set of rollers, resulting in less current loss. It also avoids the problem that heat tends to concentrate on the rollers, leading to poor heating of the metal sheet, which is common with materials like titanium alloys, whose resistivity is lower than that of the rollers.
[0037] 7. This invention provides an advanced electrically assisted metal sheet forming apparatus that can realize the processing concept of low cost, high efficiency and high quality.
[0038] 8. In this invention, the current is directly applied to the metal plate, which can result in a lower content of small-angle grain boundaries inside, effectively reducing the deformation resistance of the material, reducing the bending springback angle of the titanium alloy, and allowing the sample to be completely molded with good surface quality.
[0039] 9. This invention uses electric pulse-assisted roll forming, which results in high forming quality, low springback of parts, uniform heating, high precision, no limitation on part length, and can be used to form long parts. It is suitable for processing and forming complex components with thin walls and deep cavities. Attached Figure Description
[0040] Figure 1 This is a schematic diagram of the structure of the device of the present invention;
[0041] Figure 2 This is a partial front view cross-sectional structural diagram of the metal sheet of the present invention undergoing the first roll forming process.
[0042] Figure 3 This is a schematic diagram of the main cross-sectional structure of the roll forming process of the present invention in different passes;
[0043] Figure 4 This is a schematic diagram showing the cross-sectional shape changes of products formed by roll forming in different passes according to the present invention;
[0044] In the diagram: 1-First upper roller, 2-Second upper roller, 3-Third upper roller, 4-First lower roller, 5-Second lower roller, 6-Third lower roller, 7-Metal sheet, 8-Upper surface insulating cloth, 9-Lower surface insulating cloth, 10-First brush, 11-Second brush, 12-Pulse power supply, 13-First driven roller, 14-First driving roller, 15-Second driven roller, 16-Second driving roller, 17-Shaping upper roller, 18-Shaping lower roller. Detailed Implementation
[0045] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.
[0046] Example 1
[0047] A metal sheet electric pulse assisted roll forming device includes a roll forming die, an insulating heat insulation component and an electric pulse component.
[0048] The rolling die includes multiple sets of corresponding upper and lower rollers. Along the metal sheet conveying direction, the die surface bending angle and rolling surface width of the lower roller gradually decrease, that is, the die surface bending angle and rolling surface width of the lower roller near the discharge port are smaller than those of the lower roller near the feed port.
[0049] In this embodiment, the insulation and heat insulation component includes an insulation and heat insulation cloth, which can be covered on the surface of the metal sheet using a roll forming die, an electric pulse component brush, and a pulse power supply connected to the brush. The brush contacts the metal sheet and can heat the metal sheet.
[0050] Example 2
[0051] A highly efficient electro-pulse assisted roll forming method and apparatus for titanium alloy thin plates includes a roll forming die, an insulating and heat-insulating component, an electro-pulse device, and a shaping die. The insulating and heat-insulating component is built based on the roll forming die, and the sheet metal is heated by the electro-pulse device. The roll forming die includes an upper roller and a lower roller. The insulating and heat-insulating component includes a driving roller and a high-silica cloth. The electro-pulse device includes a brush, a wire, and a power supply. The shaping die includes multiple sets of corresponding, non-energized upper and lower rollers for geometric shaping of the pre-formed part. In this embodiment, the experimental apparatus uses a method of sequentially arranged multiple passes of specific contour rollers and applying pulsed current during the sheet metal deformation process to gradually laterally bend the sheet metal with reduced forming resistance to produce a long strip profile with a specific cross-section.
[0052] Example 3
[0053] A high-efficiency electrical pulse-assisted device for hot roll forming of multi-layer titanium alloy sheets, such as Figure 1As shown, it mainly consists of four parts: preforming roll forming molds, insulation and heat insulation components, electric pulse equipment, and shaping molds. The positional connection between them is as follows: there are multiple sets of preforming roll forming molds on the frame, and the sheet material is placed between the upper roller and the lower roller; the high silica cloth in the insulation and heat insulation components is tightly wrapped around the surface of the roll forming molds and the driving and driven rollers, and rotates under the drive of the molds. The cloth adheres tightly to the surface of the sheet material during the roll forming process; the brushes of the electric pulse equipment are located on both sides of the inlet and outlet of the preforming roll forming molds to achieve continuous contact with the sheet material. The brushes are connected to the power supply outside the frame to supply power to the sheet material. The shaping mold is located after the brushes.
[0054] Roll forming die: Specifically includes upper rollers and lower rollers. The rotation axes of the first upper roller 1, the second upper roller 2, and the third upper roller 3 are located on the same horizontal plane and have the same dimensions. The first lower roller 4, the second lower roller 5, and the third lower roller 6 are respectively located below the first upper roller 1, the second upper roller 2, and the third upper roller 3. The rotation axes of each set of upper and lower rollers are located on the same vertical plane perpendicular to the horizontal plane, but the shapes and dimensions of the first lower roller 4, the second lower roller 5, and the third lower roller 6 are different. As the rolling process progresses, the bending angle of the die surface and the width of the rolled surface gradually decrease from the first lower roller 4 to the third lower roller 6.
[0055] Insulation and heat insulation components: Improved based on the preforming roll forming die, mainly introducing a first driven roller 13, a first driving roller 14, a second driven roller 15, a second driving roller 16, and an upper surface high-silica cloth (upper surface insulation and heat insulation cloth 8) and a lower surface high-silica cloth (lower surface insulation and heat insulation cloth 9) for insulation and heat insulation. The first driven roller 13, the first driving roller 14, the second driven roller 15, and the second driving roller 16 are located above and below the preforming feed inlet and the preforming discharge outlet, respectively, and work with the preforming roll forming die to install the upper surface insulation and heat insulation cloth 8 and the lower surface insulation and heat insulation cloth 9, so that the upper surface insulation and heat insulation cloth 8 and the lower surface insulation and heat insulation cloth 9 rotate under the drive of the upper and lower rollers. In the electro-pulse assisted roll forming process, such as Figure 2 As shown, on the one hand, the upper surface insulating cloth 8 and the lower surface insulating cloth 9 isolate the heat conduction and electrical conduction between the upper and lower rollers and the metal sheet 7, ensuring the safety of the rolling equipment; on the other hand, the upper surface insulating cloth 8 and the lower surface insulating cloth 9 cover the surface of the metal sheet 7, hindering its convective heat exchange with the air, thus keeping the metal sheet 7 warm.
[0056] The electrical pulse device includes a first brush 10, a second brush 11, and a pulse power supply 12. The first brush 10 and the second brush 11 are located on both sides of the preforming inlet and preforming outlet of the preforming roll forming die, respectively, and are always in contact with the moving metal sheet 7. They are used to energize the metal sheet 7. At the same time, they are connected to the pulse power supply 12 through wires. The output current is adjusted by the voltage and pulse frequency buttons on the pulse power supply 12, thereby controlling the forming temperature of the metal sheet 7.
[0057] The forming mold specifically includes an upper forming roller 17 and a lower forming roller 18 that are not powered. The rotation axes of the upper forming roller 17 and the preforming upper roller are located on the same horizontal plane, and the lower forming roller 18 is correspondingly located below the upper forming roller 17. The rotation axes of both the upper and lower forming rollers are located on the same vertical plane that is perpendicular to the horizontal plane.
[0058] The functions of the main components in the device of this embodiment are as follows:
[0059] Lower roller: Its active rotation provides driving force for the sheet material to enter the forming die surface and deform continuously, while simultaneously bending the sheet material laterally.
[0060] Upper roller: rotates driven, while pressing down on the sheet material.
[0061] Pulse power supply: supplies power to the sheet metal.
[0062] Electric brushes: Connected to the power supply via wires, when both brushes on both sides contact the sheet material simultaneously, a circuit is formed, which heats the sheet material by passing electricity through it.
[0063] High-silica cloth: Insulates the sheet material from electrical and thermal conduction to the rolling equipment and prevents temperature loss caused by heat exchange between the sheet material and the air.
[0064] Main and driven rollers: High-silica cloth is installed in conjunction with the rollers and rotates synchronously with the forming rollers to facilitate the recycling of high-silica cloth.
[0065] The working principle of the device in this embodiment is as follows:
[0066] High-silica cloth is installed on the roller pressing die and the driving and driven rollers. The rollers are started to rotate, and the cloth rotates synchronously, pushing the sheet material into the roller pressing equipment along the length direction. It is pre-formed by the continuous biting of the upper and lower rollers and keeps in contact with the electric brush on the side of the pre-forming feed port. The electric pulse equipment is started. When the pre-formed part contacts the electric brush on the side of the pre-forming discharge port, the sheet material is subjected to pulse current and quickly reaches the forming temperature. The upper and lower insulation heat insulation components (high-silica cloth) of the sheet material are in a free loading state on both sides to ensure that they do not break. Roll forming continues under continuous power supply until, after a period of time, the pre-formed part is completed under power supply. The formed part enters the shaping die for geometric shaping. Finally, the shaped sheet material is cut out.
[0067] like Figure 3 As shown, in this embodiment, the metal sheet undergoes three rolling passes and one shaping rolling pass sequentially. The first upper roller 1 and the first lower roller 4 perform the first rolling pass; the second upper roller 2 and the second lower roller 5 perform the second rolling pass; the third upper roller 3 and the third lower roller 6 perform the third rolling pass; and the shaping upper roller 17 and the lower roller 18 perform the final shaping rolling pass. Because the die surface bending angle and rolling surface width gradually decrease from the first lower roller 4 to the third lower roller 6, as... Figure 4 As shown, the metal sheet gradually bends from a flat structure into a V-shaped plate.
[0068] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.
Claims
1. A metal sheet electropulse assisted roll forming device, characterized in that, This includes rolling dies, insulation components, and electrical pulse components; The roller pressing die includes multiple sets of upper rollers and lower rollers; The insulating and heat-insulating component includes an insulating and heat-insulating cloth that can be covered on the surface of a metal sheet by a roll forming die; The electrical pulse assembly includes a brush in contact with the metal sheet and a pulse power supply connected to the brush.
2. The electro-pulse assisted roll forming apparatus for metal sheets according to claim 1, characterized in that, The insulating and heat-insulating cloth includes high-silica cloth.
3. The electro-pulse assisted roll forming apparatus for metal sheets according to claim 1, characterized in that, The insulating and heat-insulating cloth covers the upper and lower surfaces of the metal sheet.
4. The electropulse-assisted roll forming apparatus for metal sheets according to claim 1, characterized in that, The insulation and heat insulation assembly also includes an active roller and a driven roller for cooperating with a rolling die to cover the surface of the metal sheet with the insulation and heat insulation cloth.
5. The electropulse-assisted roll forming apparatus for metal sheets according to claim 1, characterized in that, Along the direction of sheet metal conveying, the bending angle of the die surface and the width of the rolling surface of the lower roller gradually decrease.
6. The electro-pulse assisted roll forming apparatus for metal sheets according to claim 1, characterized in that, The rotation axes of the upper rollers of the roller pressing die are located on the same horizontal plane, and the lower rollers are correspondingly placed below the upper rollers. The rotation axes of each set of upper and lower rollers are located on the same vertical plane perpendicular to the horizontal plane.
7. The electro-pulse assisted roll forming apparatus for metal sheets according to claim 1, characterized in that, It also includes a shaping mold, which comprises multiple sets of non-electrically powered upper and lower shaping rollers.
8. A method for electro-pulse assisted roll forming of thin metal sheets, characterized in that, The apparatus described in any one of claims 1 to 7 shall be used.
9. The method for electro-pulse assisted roll forming of thin metal sheets according to claim 8, characterized in that, Includes the following steps: The metal sheet is pushed into the device along its length. It is pre-formed by multiple sets of upper and lower rollers of the roll forming die and keeps in contact with the brush on the pre-forming inlet side. The pulse power supply is started. When the pre-formed part contacts the brush on the pre-forming outlet side, the metal sheet is rapidly heated to the forming temperature by the pulse current. Roll forming continues under continuous power supply. The upper and lower insulating heat insulation cloths of the metal sheet are in a free loading state on both sides to ensure that it does not break. After being powered for a period of time, the pre-formed part is obtained after all passes. The pre-formed part enters the shaping die for geometric shaping. Finally, the shaped sheet is cut out.
10. The method for electro-pulse assisted roll forming of thin metal sheets according to claim 9, characterized in that, The cross-sectional shape of the formed plate is V-shaped or U-shaped; The peak current of the pulse power supply is ≥15000A, and the current density is 2.0~5.0A / mm². 2 The duty cycle is 20% to 40%; The metal sheet has a thickness of 0.3 to 2 mm and a length of >1 m, and the material includes titanium alloy or lightweight high-strength steel.