A method for integral molding of carbon fiber composite parts and its application

Abstract

This application provides a method for integral molding of carbon fiber composite parts and its application. The method includes: laying carbon fiber prepreg onto a first mold and a second mold respectively, and fixing them with adhesive to obtain a first layup assembly and a second layup assembly; placing the first layup assembly and the second layup assembly into an autoclave for a first curing treatment to obtain a first intermediate part and a second intermediate part; demolding and sanding the first intermediate part and the second intermediate part; assembling multiple first intermediate parts and second intermediate parts into a third mold in a preset order; laying carbon fiber prepreg onto a preset area in the third mold and fixing it with adhesive to obtain a blank; placing the blank into an autoclave for a second curing treatment; and demolding and sanding the blank after the second curing treatment to obtain the carbon fiber composite part. This application uses a combination of co-bonding and co-curing processes to effectively alleviate the problem of poor part consistency.

Description

Technical Field

[0001] This application relates to the field of carbon fiber composite materials technology, and in particular to a method for integral molding of carbon fiber composite parts and its application. Background Technology

[0002] Carbon fiber reinforced resin matrix composites are widely used in the fields of aviation, aerospace, spacecraft, and missiles. Carbon fiber composites have high specific strength and specific height, possessing unique advantages that metals cannot match. The specific strength of modified epoxy resin carbon fiber composites can be 10 times higher than that of aluminum alloys, and the specific stiffness can be 4 times higher than that of aluminum alloys. When applied to aircraft materials, they can significantly reduce the structural weight of aircraft.

[0003] Carbon fiber composites made from multi-directional braided carbon fiber possess excellent thermal conductivity, low coefficient of thermal expansion, high specific heat capacity, and high emissivity, exhibiting good thermal shock resistance and ablation resistance. They can also be used in support structures for civilian rockets. However, when using compression molding, controlling the mold gap during pre-molding and placement is challenging, leading to difficulties in weight control and poor consistency of the finished parts. Summary of the Invention

[0004] This application provides a method for integral molding of carbon fiber composite parts and its application, in order to solve the problem of poor consistency in carbon fiber composite parts prepared by compression molding.

[0005] In a first aspect, this application provides a method for integral molding of carbon fiber composite material parts, including:

[0006] Carbon fiber prepreg is laid on the first mold and the second mold respectively, and fixed with adhesive to obtain the first layup group and the second layup group;

[0007] The first and second layup groups are placed in an autoclave for a first curing process to obtain the first intermediate part and the second intermediate part.

[0008] Demolding and polishing the first intermediate component and the second intermediate component;

[0009] Multiple first intermediate components and second intermediate components are assembled into a third mold in a preset order;

[0010] The carbon fiber prepreg is laid onto a preset area in the third mold and fixed with adhesive to obtain a blank;

[0011] The blank is placed in an autoclave for a second curing process.

[0012] The blank after the second curing treatment is demolded and polished to obtain a carbon fiber composite material part.

[0013] In one possible implementation, before applying the carbon fiber prepreg to the first mold and the second mold respectively, the method further includes: using an air gun to remove dust from the surfaces of the first mold and the second mold, and using acetone to clean stains on the first mold and the second mold.

[0014] In one possible implementation, the adhesive is one or more combinations of epoxy resin, phenolic resin, urea-formaldehyde resin, polyurethane, polyvinyl acetal, chlorinated polyvinyl chloride resin, chloroprene rubber, and nitrile rubber.

[0015] In one possible implementation, the first process temperature of the first curing treatment is 150~200℃, and the reaction time is 2~5h.

[0016] In one possible implementation, the second process temperature for the second curing treatment is 160~250℃, and the reaction time is 2~4h.

[0017] In one possible implementation, in the step of assembling multiple first intermediate components and second intermediate components into a third mold in a preset order, the first intermediate components and the second intermediate components form a hollow cylinder, and the hollow region of the hollow cylinder is a preset region.

[0018] In one possible implementation, after obtaining the first ply group and the second ply group, the method further includes:

[0019] Release films are adhered to the surfaces of the first and second layup groups respectively, and then placed on a flat tooling to seal vacuum bags.

[0020] In one possible implementation, the curing process in the autoclave includes:

[0021] When the temperature of the autoclave reaches 85~90℃, maintain the temperature for 50~70 minutes;

[0022] After holding the temperature for 50-100 minutes, the autoclave is heated further. When the temperature of the autoclave reaches the first process temperature or the second process temperature, it is held for 70-200 minutes.

[0023] After holding at the temperature for 70-200 minutes, the pressure is maintained in the furnace and then reduced to room temperature.

[0024] In one possible implementation, the autoclave has a heating rate of less than or equal to 1°C / min and a cooling rate of less than or equal to 1°C / min.

[0025] Secondly, this application provides an application of a method for integral molding of carbon fiber composite parts, used in the preparation of support structure components for the last stage engine in a multi-stage rocket engine.

[0026] As can be seen from the above technical solutions, this application provides a method for integral molding of carbon fiber composite parts and its application. The method includes: laying carbon fiber prepreg onto a first mold and a second mold respectively, and fixing them with adhesive to obtain a first layup group and a second layup group; placing the first layup group and the second layup group into an autoclave for a first curing treatment to obtain a first intermediate part and a second intermediate part; demolding and polishing the first intermediate part and the second intermediate part; assembling multiple first intermediate parts and second intermediate parts into a third mold in a preset order; laying carbon fiber prepreg onto a preset area in the third mold and fixing it with adhesive to obtain a blank; placing the blank into an autoclave for a second curing treatment; demolding and polishing the blank after the second curing treatment to obtain a carbon fiber composite part. This application adopts a combination of co-bonding and co-curing processes, effectively alleviating the problem of poor part consistency due to the difficulty in controlling the mold gap. Attached Figure Description

[0027] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of a carbon fiber composite material part provided in an embodiment of this application;

[0029] Figure 2 A schematic diagram of the first mold provided in an embodiment of this application;

[0030] Figure 3 A schematic diagram of the second mold provided in an embodiment of this application;

[0031] Figure 4 A schematic diagram of the third mold provided in the embodiments of this application;

[0032] Figure 5 A physical image of the carbon fiber composite material molding blank provided in the embodiments of this application;

[0033] Figure 6 A physical image of a carbon fiber composite molded part provided in an embodiment of this application. Detailed Implementation

[0034] The embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described below do not represent all embodiments consistent with this application. They are merely examples of systems and methods consistent with some aspects of this application as detailed in the claims.

[0035] Due to their low density and light weight, carbon fiber composites can be used to reduce the weight of heavy equipment, saving significant energy consumption. Because carbon fiber sheets have extremely high strength, capable of withstanding much greater pressure—several times stronger than steel plates—and possess excellent fatigue resistance, acid and alkali resistance, and oxidation resistance, carbon fiber reinforced resin matrix composites are widely used in the aerospace, spacecraft, and missile fields. Carbon fiber composites not only have high specific strength but also high specific height, possessing unique advantages unmatched by metals. Modified epoxy resin-reinforced carbon fiber composites can have a specific strength 10 times higher than aluminum alloys and a specific stiffness 4 times higher. When applied to aircraft materials, this can significantly reduce the structural weight of aircraft.

[0036] Carbon fiber composites made from multi-directional braided carbon fiber possess excellent thermal conductivity, low coefficient of thermal expansion, high specific heat capacity, and high emissivity, exhibiting good thermal shock resistance and ablation resistance. They can also be used in support structures for civilian rockets. However, when using compression molding, controlling the mold gap during pre-molding and placement is challenging, leading to difficulties in weight control and poor consistency of the finished parts.

[0037] Based on this, this application provides a method for integral molding of carbon fiber composite parts and its application, in order to solve the problem of poor consistency in carbon fiber composite parts prepared by compression molding.

[0038] like Figure 1 As shown, the method for integral molding of carbon fiber composite parts provided in this application consists of three ply groups: a first ply group, a second ply group, and an intermediate ply group. The first ply group is laid on a first mold, and the second ply group is laid on a second mold. The first ply group and the second ply group are respectively cured in an autoclave to obtain a first intermediate part and a second intermediate part. The intermediate ply group is then laid on the hollow area of ​​the hollow cylinder formed by the combination of the first intermediate part and the second intermediate part. After a second autoclave curing treatment, an integrally molded carbon fiber composite part is obtained.

[0039] The method for integral molding of carbon fiber composite parts provided in this application includes the following steps:

[0040] Step 1: The carbon fiber prepreg is laid on the first mold and the second mold respectively, and fixed with adhesive to obtain the first layup group and the second layup group; wherein, the shape of the first mold is different from that of the second mold; in one possible form, the shape of the first mold is a fan-shaped structure and the shape of the second mold is a trapezoidal structure.

[0041] Before applying the carbon fiber prepreg to the first and second molds respectively, it is necessary to use an air gun to remove dust from the surfaces of the first and second molds, and use acetone to clean the stains on the first and second molds to avoid leaving stains on the surface that may affect the molding process.

[0042] Carbon fiber prepreg is an intermediate material used in the production of carbon fiber composites. It involves bonding resin to fibers before curing and maintaining a certain storage period during which layup design and molding can be performed at any time. Carbon fiber prepreg is produced by bonding carbon fiber tows with resin pre-coated on release paper under pressure and temperature through unwinding (or carbon fiber woven fabric) processes, followed by cooling, lamination, and winding. It is also known as carbon fiber prepreg fabric.

[0043] The components of carbon fiber prepreg can be: a layer of release paper at the bottom, a finished prepreg in the middle, and a layer of polyethylene film on the surface. The finished prepreg in the middle is composed of resin and fiber.

[0044] Prepreg is made by pre-impregnating fibers with resin, then laying, shaping, and curing them in subsequent processes. Therefore, the resin in prepreg is uncured, primarily thermosetting resins. There are many types of thermosetting resins. In one possible implementation, the carbon fiber prepreg includes a prepreg solvent and a fiber cloth, wherein the prepreg solvent is one or more combinations of epoxy resin, phenolic resin, bismaleimide resin, and vinyl ester resin.

[0045] Epoxy resin is the most common and widely used prepreg for carbon fiber, while bismaleimide and cyanate resin are used in some high-temperature applications. The prepreg solvent is usually an epoxy curing agent, which is a polyetheramine modified curing agent. It has advantages such as light color, long pot life, good toughness, fast surface drying, non-sticky film surface, and high gloss. The cured product has excellent toughness and mechanical resistance. In a 25℃ experimental environment, using bisphenol A type resin with an epoxy equivalent of 180~190, the pot life (100g / 25℃) is 45 minutes; the film drying time is 3.6 hours; and the curing time is only 10 hours, facilitating molding.

[0046] In one possible implementation, the adhesive is one or more combinations of epoxy resin, phenolic resin, urea-formaldehyde resin, polyurethane, polyvinyl acetal, chlorinated polyvinyl chloride resin, chloroprene rubber, and nitrile rubber.

[0047] Lay the layers according to the designed layup method as needed, and then perform pre-compaction treatment.

[0048] According to actual needs, prepreg is laid on the surface of the first mold and the second mold respectively, with 5-6 layers laid in each laying group.

[0049] After the prepreg is laid, release film, peel-off layer, breathable felt, vacuum bag and other vacuum auxiliary materials are laid on the surface of the prepreg in sequence, and vacuum degassing is performed.

[0050] A release liner can be selected as the backing, with each side being approximately 100mm larger than the repair material; apply half of the prepared adhesive evenly onto the release liner.

[0051] Place the fabricated non-porous release membrane, the first or second layup, and the breathable felt as a whole onto a flat fixture, seal the vacuum bag, evacuate for 2 to 3 minutes, and then place it back onto the flat fixture to seal the vacuum bag.

[0052] In most cases, the release liner is in direct contact with the laminate and separates it from the non-release, breathable felt. The release liner can be selected based on the curing temperature, pressure, complexity of the part, and resin system. Porous release liners remove air and volatiles embedded in the laminate.

[0053] Breathable felt is generally made of aramid fiber, which has a softening point of 170 degrees Celsius and a melting point of more than 240 degrees Celsius. It can withstand short periods of high temperatures below 200 degrees Celsius, making it convenient for repairing carbon fiber composite materials.

[0054] In some implementations, the release fabric can be used as a first barrier to separate the product from other vacuum-assisted materials. The release fabric does not stick to the product and is easily peeled off after curing, reaching approximately 230 degrees Celsius, facilitating molding.

[0055] In one possible implementation, during the sealing of the vacuum bag, the vacuuming pressure is -0.08 to -0.05 MPa, and the vacuuming time is 10 to 20 minutes.

[0056] Step 2: Place the first layup assembly and the second layup assembly into an autoclave for the first curing treatment;

[0057] Carbon fiber prepreg is laid on a mold according to the layup requirements. The blank is then sealed in a vacuum bag and placed in a carbon fiber autoclave. Under vacuum conditions, the autoclave undergoes processes such as heating, pressurizing, holding, cooling, and depressurizing. The uniform temperature and pressure simultaneously provided within the autoclave achieve curing, resulting in carbon fiber composite parts with high surface and internal quality and complex shapes. A key reason for using an autoclave is to provide sufficient pressure to the prepreg, thereby suppressing porosity formation. This results in products with excellent performance, suitable for use as structural components.

[0058] Curing is a necessary step in every carbon fiber product process. It involves heating and pressurizing the thermosetting resin in the prepreg under fixed process conditions to form a relatively stable three-dimensional network structure. For thermosetting carbon fiber composites, once cured, all defects caused by layup or the curing process are irreversible. Therefore, strict control of process parameters is crucial during autoclave curing.

[0059] In one possible implementation, placing the first layup assembly and the second layup assembly into an autoclave for a first curing process includes:

[0060] When the temperature of the autoclave reaches 85~90℃, maintain the temperature for 50~100 minutes;

[0061] After holding the temperature for 50-70 minutes, the autoclave is heated further, and when the temperature of the autoclave reaches 150-200℃, it is held for 70-200 minutes.

[0062] After holding at a temperature of 70-200 minutes, the pressure is maintained in the furnace and then reduced to room temperature to obtain the first or second intermediate part.

[0063] In one possible implementation, the heating rate of the autoclave is less than or equal to 1°C / min, and the cooling rate of the autoclave is less than or equal to 1°C / min.

[0064] In one possible implementation, the initial vacuum pressure of the autoclave curing process is greater than or equal to -0.08 MPa, and the vacuum pressure during the curing process is 0.68~0.72 MPa.

[0065] Step 3: Demold and polish the first intermediate part and the second intermediate part;

[0066] Step 4: Assemble multiple first intermediate components and second intermediate components into a third mold in a preset order; the shape of the third mold is different from that of the first mold and the second mold. In one possible implementation, the shape of the third mold is hexagonal; in another possible implementation, the preset order is that they are placed at intervals, that is, the left and right sides of the first intermediate component are the second intermediate components, and the second intermediate components are placed in the same way.

[0067] After the first and second intermediate components are assembled in the third mold, the joint between the first and second intermediate components is twisted to ensure that there are no defects such as missing parts or gaps at the connection.

[0068] Step 5: Lay the carbon fiber prepreg onto the preset area in the third mold and fix it with adhesive to obtain a blank; in the third mold, the first intermediate part and the second intermediate part form a hollow cylinder, and the hollow area of ​​the hollow cylinder is the preset area;

[0069] Step 6: Place the blank into an autoclave for a second curing treatment;

[0070] In one possible implementation, the second curing process in an autoclave includes:

[0071] When the temperature of the autoclave reaches 85~90℃, maintain the temperature for 50~100 minutes;

[0072] After holding the temperature for 50-70 minutes, the autoclave is heated further, and when the temperature of the autoclave reaches 160-250°C, it is held for 70-140 minutes.

[0073] After holding at temperature for 70-140 minutes, the pressure is maintained in the furnace and then reduced to room temperature. The heating rate, cooling rate, and vacuum pressure are the same as those in the first curing treatment.

[0074] Step 7: Demold and grind the blank after the second curing treatment to obtain the carbon fiber composite material part.

[0075] This application employs a combination of co-bonding and co-curing processes, utilizing the mature autoclave molding technology, resulting in high surface quality and dimensional accuracy of the manufactured parts. The autoclave molding process also boasts a high success rate in passing non-destructive testing on the first attempt, leading to high part consistency.

[0076] Secondly, this application provides an application of a method for integral molding of carbon fiber composite parts, used in the preparation of support structure components for the last stage engine in a multi-stage rocket engine.

[0077] Example

[0078] First, the component is designed separately, and the component is divided into ply areas for plying. The component ply is divided into eight ply groups around the perimeter (i.e., four first ply groups and four second ply groups) and a central ply group, for a total of nine ply groups. Ply design is carried out for each ply group, and the ply boundary of each layer is set.

[0079] Based on the part layup, the mold is designed in segments, and a combination mold is designed. The first mold, the second mold, and the third mold are designed as follows: Figure 2 , Figure 3 and Figure 4 As shown.

[0080] Use an air gun to blow away dust and other residues. Then, use a non-woven cloth soaked in acetone to wipe the first and second molds until there are no obvious stains on the surface of the non-woven cloth.

[0081] Collect T300 woven prepreg and T700 unidirectional tape that match the part's layup information.

[0082] First, lay out the eight surrounding layup sets, each requiring 5-6 layers. During the laying process, vacuum degassing is necessary to ensure complete removal of interlayer air bubbles. Lay out the release film, peel-off layer, breathable felt, vacuum bag, and other vacuum-aided materials sequentially on the prepreg surface, and then perform vacuum degassing. The specific steps are as follows:

[0083] Lay the peel-off layer, non-porous release film, breathable felt, and vacuum bag sequentially on the surface of the part. The edge of the non-porous release film should be at least 25mm larger than the edge of the part, but should not cover the vacuum nozzle area. Connect at least one thermocouple to each diagonal margin area of ​​the part. If the mold length is greater than 2m, place 3 or more thermocouples. Affix sealing tape around the tooling. Use a vacuum bag to make the bag, which must cover all bag-making materials. Vacuum at at least -0.080Mpa for at least 15min. Ensure that the release film, breathable felt, and vacuum bag are tightly attached to the surface of the part, without bridging or tension, and must conform to the shape. Check the sealing of the vacuum bag multiple times. If any leakage or venting is found, check the location of the leakage and cover it with sealing tape. Finally, ensure the sealing of the entire working system during vacuuming.

[0084] The part is placed in an autoclave for molding and curing.

[0085] After vacuum bagging, the parts undergo autoclave curing treatment:

[0086] The assembled parts are placed into an autoclave, the vacuum line and thermocouple are connected, and a vacuum leak check is performed. After the check is passed, the autoclave door is closed, and curing begins. After the vacuum leak check is passed, the vacuum pressure should reach above -0.08 MPa at the start of curing. Then, the temperature and pressure are increased to 0.7 MPa.

[0087] First curing treatment: When the part temperature is raised to 90℃, hold for 60 minutes, then continue to raise the temperature to 125℃ and hold for 90 minutes; the heating rate is less than or equal to 1℃ / min.

[0088] The furnace is pressurized and cooled (cooling rate less than or equal to 1℃ / min). When the temperature of the mold inside the tank drops to room temperature, the pressure is released and the contents are removed from the tank.

[0089] After cooling to room temperature, remove the surface covering of the product, ensuring no residue remains; clean any lumps or burrs from the surface; demold the parts, taking care not to damage them; grind and smooth the exposed surfaces of the repaired areas.

[0090] The eight layup molds were arranged according to Figure 4 After the mold is assembled, the joints of the eight ribbed ply groups are twisted to ensure that there are no defects or gaps at the joints.

[0091] The tooling to be formed shall be in accordance with the attached Figure 4 After the components are assembled, the intermediate lay-up units are laid. Each lay-up unit requires 5-6 layers. During the laying process, vacuum degassing is required to ensure that air bubbles between the layers are completely removed. Vacuum auxiliary materials such as release film, peel-off layer, breathable felt, and vacuum bag are sequentially laid on the surface of the prepreg, and vacuum degassing is performed. The treatment method is the same as described above and will not be repeated.

[0092] Second curing treatment: When the part temperature is raised to 90℃, hold for 60 minutes, then continue to raise the temperature to 125℃ and hold for 90 minutes; wherein the heating rate is less than or equal to 1℃ / min.

[0093] After the blank part has cured, it is demolded. After demolding, the carbon fiber composite molded blank part is as follows: Figure 5 As shown.

[0094] After the blank part is demolded, it undergoes CNC machining using a specialized composite material CNC machine tool. The finished part, after machining, is as follows: Figure 6 As shown;

[0095] After CNC machining, the parts undergo non-destructive testing using the pulse-echo method. Non-destructive testing can be divided into three methods: visual inspection, ultrasonic testing, or X-ray non-destructive testing. Once the carbon fiber product has cured and formed, the surface is first visually inspected to check for problems such as white spots, insufficient glue, or glue accumulation. Internal inspection typically uses ultrasonic or X-ray non-destructive testing, which can reveal different morphologies based on the material's density and can also detect dense voids and delamination within the material. The non-destructive testing showed that the parts fully comply with the Class A requirements of GJB 2895-1997, and the parts are qualified.

[0096] As can be seen from the above technical solutions, this application provides a method for integral molding of carbon fiber composite parts and its application. The method includes: laying carbon fiber composite materials onto a first mold and a second mold respectively, and fixing them with adhesive to obtain a first layup group and a second layup group; wherein, the first mold is different from the second mold.

[0097] The first and second layup groups are placed in an autoclave for a first curing treatment to obtain a first intermediate part and a second intermediate part. The first and second intermediate parts are then demolded and sanded. Multiple first and second intermediate parts are assembled into a third mold in a predetermined order. The third mold is different from the first and second molds. Carbon fiber composite material is laid onto a predetermined area in the third mold and fixed with adhesive to obtain a blank. The blank is placed in an autoclave for a second curing treatment. The blank after the second curing treatment is demolded and sanded to obtain a carbon fiber composite part. This application employs a combination of co-bonding and co-curing processes, effectively alleviating the problem of poor part consistency due to the difficulty in controlling mold gaps.

[0098] Similar parts between the embodiments provided in this application can be referred to mutually. The specific implementation methods provided above are only a few examples under the overall concept of this application and do not constitute a limitation on the scope of protection of this application. For those skilled in the art, any other implementation methods extended from the solution of this application without creative effort shall fall within the scope of protection of this application.

Claims

1. A method for integral molding of carbon fiber composite material parts, characterized in that, include: Carbon fiber prepreg is laid on the first mold and the second mold respectively, and fixed with adhesive to obtain the first layup group and the second layup group; The first and second layup groups are placed in an autoclave for a first curing treatment to obtain a first intermediate part and a second intermediate part; the first process temperature of the first curing treatment is 150~200℃, and the reaction time is 2~5h. Demolding and polishing the first intermediate component and the second intermediate component; Multiple first intermediate components and second intermediate components are assembled into a third mold in a preset order; The carbon fiber prepreg is laid onto a preset area in the third mold and fixed with adhesive to obtain a blank; The blank is placed in an autoclave for a second curing treatment; the second process temperature for the second curing treatment is 160~250℃, and the reaction time is 2~4h; the initial vacuum pressure of the autoclave curing treatment is greater than or equal to -0.08MPa, and the vacuum pressure during the curing treatment is 0.68~0.72MPa; The blank after the second curing treatment is demolded and polished to obtain a carbon fiber composite material part. In the step of assembling multiple first intermediate components and second intermediate components into the third mold in a preset order, the first intermediate components and the second intermediate components form a hollow cylinder, and the hollow area of ​​the hollow cylinder is a preset area.

2. The method for integral molding of carbon fiber composite parts according to claim 1, characterized in that, Before applying the carbon fiber prepreg to the first mold and the second mold respectively, the method further includes: using an air gun to remove dust from the surfaces of the first mold and the second mold, and using acetone to clean stains on the first mold and the second mold.

3. The method for integral molding of carbon fiber composite parts according to claim 1, characterized in that, The adhesive is one or more of the following: epoxy resin, phenolic resin, urea-formaldehyde resin, polyurethane, polyvinyl alcohol acetal, chlorinated polyvinyl chloride resin, chloroprene rubber, and nitrile rubber.

4. The method for integral molding of carbon fiber composite parts according to claim 1, characterized in that, After obtaining the first ply group and the second ply group, the method further includes: Release films are adhered to the surfaces of the first and second layup groups respectively, and then placed on a flat tooling to seal vacuum bags.

5. The method for integral molding of carbon fiber composite parts according to claim 1, characterized in that, The curing process in the autoclave includes: When the temperature of the autoclave reaches 85~90℃, maintain the temperature for 50~70 minutes; After holding the temperature for 50-100 minutes, the autoclave is heated further. When the temperature of the autoclave reaches the first process temperature or the second process temperature, it is held for 70-200 minutes. After holding at the temperature for 70-200 minutes, the furnace is kept under pressure and cooled to room temperature.

6. The method for integral molding of carbon fiber composite parts according to claim 5, characterized in that, The heating rate of the autoclave is less than or equal to 1℃ / min, and the cooling rate of the autoclave is less than or equal to 1℃ / min.

7. The application of the method for integral molding of carbon fiber composite parts according to any one of claims 1-6, characterized in that, Applications in the manufacture of support structures for the last stage of a rocket multistage engine.

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