Foil strip reinforcing rib structure and preparation method thereof

Abstract

The invention relates to a foil strip reinforcing rib structure and a preparation method thereof, and belongs to the field of foil packaging, the preparation method comprises the following steps: firstly, blanking a reinforcing rib thin plate, a foil and a base plate according to a design size, and reserving a margin on the outer contour of the reinforcing rib thin plate; then surface cleaning and protection are conducted; the reinforcing rib thin plate and the foil are stacked between two layers of base plates, the temperature is increased to 950-1100 DEG C under the vacuum condition, then the pressure is increased to 18-25 MPa, heat preservation and pressure maintaining are conducted for 5-8 h, and a part is taken after cooling; according to the method, the foil and the reinforcing rib are connected through the diffusion connection technology, and through the diffusion connection process design, the surface quality is improved, and the connection strength is improved. And the application range of the foil is expanded, and a new feasible path is provided for preparation of an ultrathin structure.

Description

Technical Field

[0001] This invention belongs to the field of foil packaging, specifically relating to a foil structure with reinforcing ribs and its preparation method. Background Technology

[0002] In aerospace, automotive manufacturing, and rail transportation, many functional components are encapsulated using foil. To achieve functional-structural integration, it is necessary to design reinforced structures to improve structural rigidity. However, the connections between foil and thin plates, achieved through brazing, riveting, or fusion welding, suffer from issues such as low joint strength, poor surface quality, and poor fatigue performance.

[0003] Diffusion bonding is a solid-state bonding technique that uses microscopic plastic deformation of two clean contact surfaces under specific temperature and pressure conditions. This deformation, achieved through interatomic diffusion, results in a metallurgical bond between materials. The joints exhibit high strength, comparable to that of the base materials. There is no heat-affected zone, avoiding defects such as solidification structures, cracks, and porosity common in traditional fusion welding. The bonding process is slow, with minimal heat input and plastic deformation, resulting in minimal residual stress and deformation. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a foil material with reinforcing ribs and its preparation method. The invention uses diffusion bonding technology to connect the foil material and the reinforcing ribs. Through diffusion bonding process design, the surface quality of the foil material with reinforcing ribs is improved and the connection strength is increased.

[0005] The above-mentioned objectives of the present invention are mainly achieved through the following technical solutions:

[0006] A foil material with reinforcing ribs and its preparation method, comprising the following steps:

[0007] (1) Cut the reinforcing rib sheet, foil and pad according to the design dimensions, and leave a margin on the outer contour of the reinforcing rib sheet;

[0008] (2) Clean and protect the surface of the reinforcing rib sheet, foil and pad obtained in step (1);

[0009] (3) The reinforcing rib sheet and foil obtained in step (2) are stacked between two layers of pads, heated under vacuum conditions, heated to 950-1100℃ and then pressurized to 18-25MPa, and kept at the temperature and pressure for 5-8 hours. After cooling, the parts are removed.

[0010] (4) Remove excess material from the reinforcing rib thin plate.

[0011] The reinforcing rib plate has a grid-like frame structure.

[0012] In step (1), a margin of 2 to 10 mm is left on the outer contour of the reinforcing rib sheet.

[0013] In step (2), the protection method is to spray an isolation agent that prevents diffusion bonding on the side of the pad that contacts the foil and the reinforcing rib plate.

[0014] The separating agent is BN.

[0015] In step (3), the vacuum degree is 10. -2 Below Pa.

[0016] The foil has a thickness of 0.01 to 0.1 mm.

[0017] The thickness of the reinforcing rib is 0.2 to 0.5 mm.

[0018] The foil and reinforcing ribs are made of 304 stainless steel foil, the pad is made of stainless steel, and the pressure mold is made of graphite mold.

[0019] A foil material with reinforcing ribs is prepared according to the above-described preparation method.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] (1) The present invention provides a method for preparing a foil material with reinforcing ribs, which uses diffusion bonding technology to connect the foil material and the reinforcing ribs. Through diffusion bonding process design, the surface quality is improved and the bonding strength is increased.

[0022] (2) The preferred flat graphite mold and stainless steel pad used in the embodiments of the present invention are easy to process and can significantly reduce costs by replacing special tooling. The stainless steel pad with good plasticity can effectively apply diffusion pressure and avoid the carbonization effect of graphite mold on foil. By using appropriate process parameters, the preparation of ultra-thin stainless steel foil with reinforcing ribs can be achieved, which expands the application range of foil and provides a new feasible path for the preparation of ultra-thin structures. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the stainless steel foil material with reinforcing ribs of the present invention;

[0024] Figure 2 This is a schematic diagram of the vacuum diffusion connection assembly with reinforcing ribs of the present invention;

[0025] Figure 3 This is a cross-sectional view of the vacuum diffusion connection assembly with reinforcing ribs of the present invention. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments:

[0027] For example Figure 1The stainless steel foil ultrathin structure with reinforcing ribs shown has several drawbacks. Brazing presents problems such as high-temperature joint melting and detachment; riveting results in batch joint failures, stress concentration leading to foil breakage, and improper riveting parameter control causing foil melting; fusion welding suffers from weld excess and welding deformation affecting surface quality. This invention provides a method for preparing an ultrathin stainless steel foil structure with reinforcing ribs. The diffusion bonding technology produces an ultrathin stainless steel foil structure with reinforcing ribs that exhibits good surface quality and high connection strength.

[0028] This invention utilizes vacuum diffusion bonding technology to fabricate ultrathin structures with reinforcing ribs on stainless steel foil. For example... Figure 2 As shown, the blank to be diffused bonded is placed between two layers of stainless steel plates, and pressure is applied to it through a high-temperature resistant and rigid graphite mold to complete the diffusion bond under high-temperature vacuum conditions.

[0029] The main process is as follows:

[0030] (1) Cutting. Cut the reinforcing rib sheet, foil, and pad according to the design dimensions. Leave a 2mm to 10mm allowance on the outer contour of the reinforcing rib sheet, and round off sharp edges. The surfaces of the reinforcing rib, foil, and pad should be smooth and flat, without wrinkles.

[0031] (2) Surface cleaning and protection. The surfaces of the reinforcing rib sheet, foil, and backing plate are degreased and cleaned to ensure a clean surface. A release agent to prevent diffusion bonding is sprayed onto the side of the backing plate that contacts the foil and reinforcing rib sheet. The surface of the graphite mold is cleaned to ensure there are no protrusions. The foil thickness is 0.01–0.1 mm, the reinforcing rib thickness is 0.2–0.5 mm, and the release agent is BN.

[0032] (3) Vacuum diffusion bonding. For example... Figure 3 As shown, stack the mold, backing plate, reinforcing rib sheet, and foil material, and place them on the diffusion bonding equipment platform. After closing the furnace door, evacuate to 10°C. -2 Below Pa, once the required vacuum level is achieved, begin heating. When the temperature reaches 950–1100℃, increase the equipment tonnage, calculated based on the stress area of ​​the reinforcing rib plate, ensuring the reinforcing rib plate bears a stress of 18–25 MPa. Maintain heat and pressure for 5–8 hours. After the heat and pressure maintenance is complete, cool the equipment down to below 100℃ before removing the part.

[0033] (4) Removal of excess material. Remove excess material from the thin plate with reinforcing ribs.

[0034] Example 1

[0035] This example provides a method for forming an ultra-thin corrugated structure with reinforcing ribs. The material is 304 stainless steel foil with a thickness of 0.1 mm, the reinforcing ribs are 0.5 mm thick, the structural component is 500 mm long and 450 mm wide. The specific steps are as follows:

[0036] First, material preparation. Cut the reinforcing rib sheet, foil, and backing plate according to the design dimensions. Leave a 2mm-3mm allowance on the outer contour of the reinforcing rib sheet, and round off sharp edges. Leave a 10mm allowance on the outer contour of the foil compared to the reinforcing rib sheet, with a cutting size of 510mm × 460mm. Leave a 10mm allowance on the outer contour of the backing plate compared to the foil, with a cutting size of 520mm × 470mm. The surfaces of the reinforcing rib, foil, and backing plate should be smooth and flat, without wrinkles.

[0037] Second, surface cleaning and protection. The surfaces of the reinforcing rib sheet, foil, and backing plate are degreased and cleaned to ensure they are clean. A release agent to prevent diffusion bonding is sprayed onto the side of the backing plate that contacts the foil and reinforcing rib sheet. The surface of the graphite mold is cleaned to ensure it is free of protrusions.

[0038] Third, vacuum diffusion bonding. Stack the mold, backing plate, reinforcing rib sheet, and foil on the diffusion bonding equipment platform. After closing the furnace door, evacuate to 10°C. -2 Below Pa, heating begins once the required vacuum level is achieved. When the temperature reaches 970℃, the equipment tonnage is increased, and the stress-bearing area of ​​the reinforcing rib plate is 10425 mm². 2 Based on a diffusion pressure of 20 MPa, the calculated equipment tonnage is approximately 21 tons. Therefore, the equipment tonnage is set at 21 tons, and the heat and pressure are maintained for 6 hours. After the heat and pressure maintenance is completed, the equipment is cooled down to 80°C before the parts are removed.

[0039] Fourth, remove excess material. Remove excess material from the thin plates with reinforcing ribs.

[0040] The above description is only the best specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

[0041] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A foil strip stiffener structure and method of making the same, characterized by: The method comprises the following steps: (1) blanking the reinforcing rib sheet, foil and backing plate according to the design size, wherein the reinforcing rib sheet has an excess outside contour; (2) surface cleaning and protection of the reinforcing rib sheet, foil and backing plate obtained in step (1); (3) stacking the reinforcing rib sheet and foil obtained in step (2) between two layers of backing plate, heating under vacuum, pressurizing to 18-25 MPa after heating to 950-1100 ℃, and holding for 5-8 h, and taking out the product after cooling; (4) removing the excess of the reinforcing rib sheet.

2. A foil strip stiffener structure and method of making the same according to claim 1, wherein: The reinforcing rib sheet has a frame structure.

3. The foil strip stiffener structure and method of making thereof of claim 1, wherein: In step (1), the reinforcing rib sheet has an excess of 2-10 mm outside contour.

4. The foil strip stiffener structure and method of making thereof of claim 1, wherein: In step (2), the protection method is spraying a diffusion barrier on the side of the backing plate contacting the foil and reinforcing rib sheet.

5. A foil strip stiffener structure and method of making the same, according to claim 4, wherein: The diffusion barrier is BN.

6. The foil strip stiffener structure and method of making thereof of claim 1, wherein: The vacuum degree in the step (3) is 10 -2 Pa or less.

7. The foil strip stiffener structure and method of making thereof of Claim 1, wherein: The foil has a thickness of 0.01-0.1 mm.

8. The foil strip stiffener structure and method of making thereof of Claim 1, wherein: The reinforcing rib has a thickness of 0.2-0.5 mm.

9. The foil strip stiffener structure of claim 1, and method of making the same, wherein: The foil and reinforcing rib are 304 stainless steel foil, the backing plate is stainless steel backing plate, and the press mold is graphite mold.

10. A foil strip plenum structure, characterized by: Prepared according to any one of claims 1-9.

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