A carbon fiber reinforced C-shaped tube, its preparation method and applications

Abstract

This invention relates to a carbon fiber reinforced C-shaped tube, its preparation method, and its applications. The C-shaped structure of the C-shaped tube includes an inner layer and an outer layer covering the inner layer. The outer layer is a first carbon fiber prepreg layer, and the inner layer is a second carbon fiber prepreg layer. The carbon fiber content in the first carbon fiber prepreg layer is less than that in the second carbon fiber prepreg layer; the tensile strength of the carbon fibers in the first carbon fiber prepreg layer is less than that in the second carbon fiber prepreg layer; the tensile modulus of the carbon fibers in the first carbon fiber prepreg layer is less than that in the second carbon fiber prepreg layer; the resin content in the first carbon fiber prepreg layer is greater than that in the second carbon fiber prepreg layer; and the thickness of the first carbon fiber prepreg layer is less than that of the second carbon fiber prepreg layer. The C-shaped tube provided by this invention, through the design of the carbon fiber reinforced C-shaped tube, can ensure that the C-shaped tube is integrally formed, and the use of the inner and outer layer design significantly improves the mechanical properties of the resulting carbon fiber reinforced C-shaped tube.

Description

Technical Field

[0001] This invention relates to the field of carbon fiber reinforced materials, specifically to a carbon fiber reinforced C-shaped tube, its preparation method, and its applications. Background Technology

[0002] Currently, carbon fiber reinforced resin matrix composites have been widely used due to their high specific strength, high specific modulus, fatigue resistance, corrosion resistance, and strong designability. Carbon fiber tubes are often mass-produced using methods such as winding and molding.

[0003] For example, CN208343575U discloses a carbon fiber reinforced high-temperature resistant composite material pipe, belonging to the field of composite material pipes. From the inside out, it comprises a stainless steel inner layer, a high-temperature heat-insulating composite material layer, an axial strength layer, and an outermost rigid layer. Specifically: the high-temperature heat-insulating composite material layer is formed by impregnating a prefabricated structure of carbon fiber and ceramic fiber mixed braided with modified resin on the surface of the stainless steel inner layer; the axial strength layer is formed by combining carbon fiber and high-temperature resistant resin on the outside of the high-temperature heat-insulating composite material layer, with the carbon fibers arranged axially; and the outermost rigid layer is formed by impregnating a high-modulus carbon fiber reinforced with high-temperature resistant resin using a two-dimensional braided structure. This composite material pipe is lightweight, heat-resistant, and exhibits good dimensional stability during processing.

[0004] For example, CN114440015A discloses a high-temperature resistant bismaleimide resin fiber-reinforced non-metallic tubing and its manufacturing method, relating to the field of oil extraction equipment technology. Specifically, it includes an inner layer of a base pipe made of bismaleimide resin and chopped carbon fiber, from the inside out; fiber tape pre-impregnated with bismaleimide resin and directly wound onto the base pipe; an outer resin layer is then applied; and the mixture is cured by heating to form a composite non-metallic tubing. The high-temperature resistant bismaleimide resin fiber-reinforced non-metallic tubing manufactured using this method features high temperature resistance, high strength, light weight, wear resistance, and corrosion resistance, showing significant improvements in temperature resistance, tensile strength, internal pressure resistance, and torsional resistance compared to existing non-metallic tubing. This non-metallic tubing can be applied to ultra-deep, high-pressure, and high-temperature oil wells, solving the engineering problems of traditional metal tubing, such as heavy weight, rapid corrosion, difficult well workover, and high operating costs.

[0005] However, current carbon fiber reinforced materials need to be processed into irregularly shaped materials, such as C-shaped tubes or concave tubes, during use. The existing C-shaped tubes are formed by completely covering the core material with carbon fiber prepreg material, and then cutting off the required C-shaped notch and hot pressing. However, this process will damage the carbon fiber structure, resulting in a significant reduction in the performance of the obtained carbon fiber reinforced material and affecting the final use effect. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a carbon fiber reinforced C-shaped tube, its preparation method and application, so as to solve the problem of poor performance of the carbon fiber reinforced C-shaped tube obtained in the prior art.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a carbon fiber reinforced C-shaped tube, wherein the C-shaped structure of the C-shaped tube includes an inner layer and an outer layer covering the inner layer, the outer layer being a first carbon fiber prepreg layer and the inner layer being a second carbon fiber prepreg layer;

[0009] The carbon fiber content in the first carbon fiber prepreg layer is less than the carbon fiber content in the second carbon fiber prepreg layer;

[0010] The tensile strength of the carbon fibers in the first carbon fiber prepreg layer is less than the tensile strength of the carbon fibers in the second carbon fiber prepreg layer.

[0011] The tensile modulus of the carbon fibers in the first carbon fiber prepreg layer is less than the tensile modulus of the carbon fibers in the second carbon fiber prepreg layer.

[0012] The resin content in the first carbon fiber prepreg layer is greater than the resin content in the second carbon fiber prepreg layer;

[0013] The thickness of the first carbon fiber prepreg layer is less than the thickness of the second carbon fiber prepreg layer.

[0014] The C-shaped tube provided by this invention, through the design of carbon fiber reinforced C-shaped tube, can ensure that the C-shaped tube is integrally formed, and the use of inner and outer layer design significantly improves the mechanical properties of the resulting carbon fiber reinforced C-shaped tube, which is beneficial to improving the performance of the carbon fiber reinforced C-shaped tube.

[0015] As a preferred embodiment of the present invention, the carbon fiber content in the first carbon fiber prepreg layer is 200-220 g / m². 2 .

[0016] Preferably, the carbon fiber content in the second carbon fiber prepreg layer is 360-400 g / m². 2 .

[0017] As a preferred technical solution of the present invention, the tensile strength of the carbon fiber in the first carbon fiber prepreg layer is 1500-1600MPa.

[0018] Preferably, the tensile strength of the carbon fibers in the second carbon fiber prepreg layer is 2200-2500 MPa.

[0019] Preferably, the tensile modulus of the carbon fibers in the first carbon fiber prepreg layer is 110-130 GPa.

[0020] Preferably, the tensile modulus of the carbon fibers in the second carbon fiber prepreg layer is 140-150 GPa.

[0021] As a preferred embodiment of the present invention, the resin content in the first carbon fiber prepreg layer is 40-45% by mass.

[0022] Preferably, the resin content in the second carbon fiber prepreg layer is 30-33% by mass.

[0023] As a preferred embodiment of the present invention, the thickness of the first carbon fiber prepreg layer is 0.25-0.28 mm.

[0024] Preferably, the thickness of the second carbon fiber prepreg layer is 0.34-0.36 mm.

[0025] In a second aspect, the present invention provides a method for preparing C-shaped tubing as described in the first aspect, the method comprising: covering a core material with the C-shaped structure, then sequentially performing a first hot pressing, a second hot pressing, a third hot pressing and a fourth hot pressing, and then removing the core material to obtain carbon fiber reinforced C-shaped tubing.

[0026] As a preferred technical solution of the present invention, the pressure in the first hot pressing is 50-60kN.

[0027] Preferably, the temperature in the first hot press is 140-150°C.

[0028] Preferably, the time in the first hot pressing is 5-8 minutes.

[0029] Preferably, the pressure in the second hot pressing is 100-120 kN.

[0030] Preferably, the temperature in the second hot press is 140-160°C.

[0031] Preferably, the time in the second hot pressing is 5-10 minutes.

[0032] As a preferred embodiment of the present invention, the pressure in the third hot pressing is 350-400kN.

[0033] Preferably, the temperature in the third hot press is 140-155°C.

[0034] Preferably, the time in the third hot pressing is 10-20 minutes.

[0035] Preferably, the pressure in the fourth hot pressing is 500-550 kN.

[0036] Preferably, the temperature in the fourth hot press is 140-170°C.

[0037] Preferably, the time in the fourth hot pressing is 70-80 minutes.

[0038] As a preferred technical solution of the present invention, the preparation method includes: coating the core material with the C-shaped structure, and then performing a first hot pressing, a second hot pressing, a third hot pressing and a fourth hot pressing in sequence, and then removing the core material to obtain a carbon fiber reinforced C-shaped tube;

[0039] The pressure in the first hot press is 50-60 kN; the temperature in the first hot press is 140-150 °C; and the time in the first hot press is 5-8 min.

[0040] The pressure in the second hot pressing is 100-120 kN; the temperature in the second hot pressing is 140-160 °C; and the time in the second hot pressing is 5-10 min.

[0041] The pressure in the third hot pressing is 350-400 kN; the temperature in the third hot pressing is 140-155 °C; and the time in the third hot pressing is 10-20 min.

[0042] The pressure in the fourth hot pressing is 500-550 kN; the temperature in the fourth hot pressing is 140-170 °C; and the time in the fourth hot pressing is 70-80 min.

[0043] Thirdly, the present invention provides the use of carbon fiber reinforced C-shaped tubing as described in the first aspect, the use of which includes using carbon fiber reinforced C-shaped tubing as a support rod.

[0044] Compared with existing technical solutions, the present invention has the following beneficial effects:

[0045] The carbon fiber reinforced C-shaped tube provided by this invention, through a reasonable design of the C-shaped tube (which can also be regarded as a grooved tube) and the adoption of a specific inner and outer layer system, enhances the mechanical properties of the resulting carbon fiber reinforced C-shaped tube, thereby ensuring the strength of the carbon fiber reinforced C-shaped tube during use and facilitating the performance of the carbon fiber reinforced C-shaped tube. The resulting carbon fiber reinforced C-shaped tube has a 0° tensile strength ≥1588.78MPa, a 0° tensile modulus ≥139.68GPa, a 90° tensile strength ≥418MPa, and a 90° tensile modulus ≥61.25GPa. Detailed Implementation

[0046] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0047] This example provides a carbon fiber reinforced C-shaped tube. The C-shaped structure of the C-shaped tube includes an inner layer and an outer layer covering the inner layer. The outer layer is a first carbon fiber prepreg layer, and the inner layer is a second carbon fiber prepreg layer.

[0048] The carbon fiber content in the first carbon fiber prepreg layer is less than the carbon fiber content in the second carbon fiber prepreg layer;

[0049] The tensile strength of the carbon fibers in the first carbon fiber prepreg layer is less than the tensile strength of the carbon fibers in the second carbon fiber prepreg layer.

[0050] The tensile modulus of the carbon fibers in the first carbon fiber prepreg layer is less than the tensile modulus of the carbon fibers in the second carbon fiber prepreg layer.

[0051] The resin content in the first carbon fiber prepreg layer is greater than the resin content in the second carbon fiber prepreg layer;

[0052] The thickness of the first carbon fiber prepreg layer is less than the thickness of the second carbon fiber prepreg layer.

[0053] For example, the C-shaped pipe can be regarded as a groove structure such as channel steel. It is not closed on the surface, but has an opening. That is, the C-shaped pipe is not necessarily formed by cutting a round pipe into a C shape. It can also be the shape of channel steel.

[0054] Specifically, the carbon fiber content in the first carbon fiber prepreg layer is 200-220 g / m². 2 For example, it could be 200g / m 2 201g / m 2 202g / m 2 203g / m 2 204g / m 2 205g / m 2 206g / m 2 207g / m 2 208g / m 2 209g / m 2 201g / m 2 211g / m 2 212g / m 2 213g / m 2 214g / m 2 215g / m 2 216g / m 2 217g / m 2 218g / m 2 219g / m 2 Or 220g / m 2The same applies to, but not limited to, the listed values; other unlisted values ​​within this range also apply.

[0055] Specifically, the carbon fiber content in the second carbon fiber prepreg layer is 360-400 g / m². 2 For example, it could be 360g / m 2 362g / m 2 364g / m 2 366g / m 2 368g / m 2 370g / m 2 372g / m 2 374g / m 2 376g / m 2 378g / m 2 380g / m 2 382g / m 2 384g / m 2 386g / m 2 388g / m 2 390g / m 2 392g / m 2 394g / m 2 396g / m 2 398g / m 2 Or 400g / m 2 The same applies to, but not limited to, the listed values; other unlisted values ​​within this range also apply.

[0056] Specifically, the tensile strength of the carbon fiber in the first carbon fiber prepreg layer is 1500-1600 MPa, for example, it can be 1500 MPa, 1510 MPa, 1520 MPa, 1530 MPa, 1540 MPa, 1550 MPa, 1560 MPa, 1570 MPa, 1580 MPa, 1590 MPa or 1600 MPa, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0057] Specifically, the tensile strength of the carbon fiber in the second carbon fiber prepreg layer is 2200-2500 MPa, for example, it can be 2200 MPa, 2220 MPa, 2240 MPa, 2260 MPa, 2280 MPa, 2300 MPa, 2320 MPa, 2340 MPa, 2360 MPa, 2380 MPa, 2400 MPa, 2420 MPa, 2440 MPa, 2460 MPa, 2480 MPa or 2500 MPa, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0058] Specifically, the tensile modulus of the carbon fiber in the first carbon fiber prepreg layer is 110-130 GPa, for example, it can be 110 GPa, 111 GPa, 112 GPa, 113 GPa, 114 GPa, 115 GPa, 116 GPa, 117 GPa, 118 GPa, 119 GPa, 120 GPa, 121 GPa, 122 GPa, 123 GPa, 124 GPa, 125 GPa, 126 GPa, 127 GPa, 128 GPa, 129 GPa or 130 GPa, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0059] Specifically, the tensile modulus of the carbon fiber in the second carbon fiber prepreg layer is 140-150 GPa, for example, it can be 140 GPa, 141 GPa, 142 GPa, 143 GPa, 144 GPa, 145 GPa, 146 GPa, 147 GPa, 148 GPa, 149 GPa or 150 GPa, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0060] Specifically, the resin content in the first carbon fiber prepreg layer is 40-45% by mass, for example, it can be 40%, 40.5%, 41%, 41.5%, 42%, 42.5%, 43%, 43.5%, 44%, 44.5% or 45%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0061] Specifically, the resin content in the second carbon fiber prepreg layer is 30-33% by mass, for example, it can be 30%, 30.2%, 30.4%, 30.6%, 30.8%, 31%, 31.2%, 31.4%, 31.6%, 31.8%, 32%, 32.2%, 32.4%, 32.6%, 32.8%, or 33%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0062] In this example, the resin in the carbon fiber prepreg layer can be epoxy resin, such as epoxy resin commonly used in the art, or epoxy resins available in the prior art, such as the epoxy resin disclosed in CN111253553A, or the epoxy resin disclosed in CN108699221A, etc.

[0063] Specifically, the thickness of the first carbon fiber prepreg layer is 0.25-0.28 mm, for example, it can be 0.25 mm, 0.252 mm, 0.254 mm, 0.256 mm, 0.258 mm, 0.26 mm, 0.262 mm, 0.264 mm, 0.266 mm, 0.268 mm, 0.27 mm, 0.272 mm, 0.274 mm, 0.276 mm, 0.278 mm or 0.28 mm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0064] Specifically, the thickness of the second carbon fiber prepreg layer is 0.34-0.36 mm, for example, it can be 0.34 mm, 0.34.2 mm, 0.34.4 mm, 0.34.6 mm, 0.34.8 mm, 0.35 mm, 0.35.2 mm, 0.35.4 mm, 0.35.6 mm, 0.35.8 mm or 0.36 mm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0065] Furthermore, the carbon fiber in the inner layer prepreg is either warp-distributed or weft-distributed, meaning it only includes carbon fiber in one direction. The carbon fiber in the outer layer prepreg is woven with warp and weft fibers, with the angle between the warp and weft fibers being 90°.

[0066] For example, the preparation method of the above-mentioned carbon fiber reinforced C-shaped tube is as follows:

[0067] The core material is covered with the C-shaped structure, and then subjected to a first hot pressing, a second hot pressing, a third hot pressing and a fourth hot pressing in sequence. After that, the core material is removed to obtain a carbon fiber reinforced C-shaped tube.

[0068] For example, the core material used in the preparation process can be aluminum, stainless steel, or plastic, such as aluminum 6063 or stainless steel 304.

[0069] Specifically, the pressure in the first hot press is 50-60kN, for example, it can be 50kN, 51kN, 52kN, 53kN, 54kN, 55kN, 56kN, 57kN, 58kN, 59kN or 60kN, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0070] Specifically, the temperature in the first hot press is 140-150℃, for example, it can be 140℃, 141℃, 142℃, 143℃, 144℃, 145℃, 146℃, 147℃, 148℃, 149℃ or 150℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0071] Specifically, the time in the first hot pressing is 5-8 minutes, for example, it can be 5 minutes, 5.2 minutes, 5.4 minutes, 5.6 minutes, 5.8 minutes, 6 minutes, 6.2 minutes, 6.4 minutes, 6.6 minutes, 6.8 minutes, 7 minutes, 7.2 minutes, 7.4 minutes, 7.6 minutes, 7.8 minutes or 8 minutes, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0072] Specifically, the pressure in the second hot pressing is 100-120kN, for example, it can be 100kN, 101kN, 102kN, 103kN, 104kN, 105kN, 106kN, 107kN, 108kN, 109kN, 110kN, 111kN, 112kN, 113kN, 114kN, 115kN, 116kN, 117kN, 118kN, 119kN or 120kN, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0073] Specifically, the temperature in the second hot press is 140-160℃, for example, it can be 140℃, 141℃, 142℃, 143℃, 144℃, 145℃, 146℃, 147℃, 148℃, 149℃, 150℃, 151℃, 152℃, 153℃, 154℃, 155℃, 156℃, 157℃, 158℃, 159℃ or 160℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0074] Specifically, the time in the second hot pressing is 5-10 minutes, for example, it can be 5 minutes, 5.5 minutes, 6 minutes, 6.5 minutes, 7 minutes, 7.5 minutes, 8 minutes, 8.5 minutes, 9 minutes, 9.5 minutes or 10 minutes, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0075] Specifically, the pressure in the third hot pressing is 350-400kN, for example, it can be 350kN, 352kN, 354kN, 356kN, 358kN, 360kN, 362kN, 364kN, 366kN, 368kN, 370kN, 372kN, 374kN, 376kN, 378kN, 380kN, 382kN, 384kN, 386kN, 388kN, 390kN, 392kN, 394kN, 396kN, 398kN or 400kN, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0076] Specifically, the temperature in the third hot press is 140-155℃, for example, it can be 140℃, 141℃, 142℃, 143℃, 144℃, 145℃, 146℃, 147℃, 148℃, 149℃, 150℃, 151℃, 152℃, 153℃, 154℃ or 155℃, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0077] Specifically, the time in the third hot pressing is 10-20 minutes, for example, it can be 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0078] Specifically, the pressure in the fourth hot pressing is 500-550kN, for example, it can be 500kN, 505kN, 510kN, 515kN, 520kN, 525kN, 530kN, 535kN, 540kN, 545kN or 500kN, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0079] Specifically, the temperature in the fourth hot press is 140-170℃, for example, it can be 140℃, 142℃, 144℃, 146℃, 148℃, 150℃, 152℃, 154℃, 156℃, 158℃, 160℃, 162℃, 164℃, 166℃, 168℃ or 170℃, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0080] Specifically, the time in the fourth hot pressing is 70-80 minutes, for example, it can be 70 minutes, 71 minutes, 72 minutes, 73 minutes, 74 minutes, 75 minutes, 76 minutes, 77 minutes, 78 minutes, 79 minutes or 80 minutes, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0081] Furthermore, the present invention provides a specific implementation process, as follows:

[0082] Example 1

[0083] This embodiment provides a carbon fiber reinforced C-shaped tube. The C-shaped structure of the C-shaped tube includes an inner layer and an outer layer covering the inner layer. The outer layer is a first carbon fiber prepreg layer, and the inner layer is a second carbon fiber prepreg layer.

[0084] The carbon fiber content in the first carbon fiber prepreg layer is 204 g / m². 2The carbon fiber content in the second carbon fiber prepreg layer is 388 g / m². 2 .

[0085] The tensile strength of the carbon fiber in the first carbon fiber prepreg layer is 1540 MPa; the tensile strength of the carbon fiber in the second carbon fiber prepreg layer is 2400 MPa; the tensile modulus of the carbon fiber in the first carbon fiber prepreg layer is 115 GPa; and the tensile modulus of the carbon fiber in the second carbon fiber prepreg layer is 147 GPa.

[0086] The resin content in the first carbon fiber prepreg layer is 42% by mass; the resin content in the second carbon fiber prepreg layer is 32% by mass. The thickness of the first carbon fiber prepreg layer is 0.26 mm; the thickness of the second carbon fiber prepreg layer is 0.35 mm.

[0087] The specific preparation process is as follows:

[0088] The core material is covered with the C-shaped structure, and then the first hot pressing, second hot pressing, third hot pressing and fourth hot pressing are performed in sequence. After that, the core material is removed to obtain carbon fiber reinforced C-shaped tube.

[0089] The pressure in the first hot press is 54 kN; the temperature in the first hot press is 147 °C; and the time in the first hot press is 7 min.

[0090] The pressure in the second hot press is 115 kN; the temperature in the second hot press is 150 °C; and the time in the second hot press is 8 min.

[0091] The pressure in the third hot press is 380 kN; the temperature in the third hot press is 142 °C; and the time in the third hot press is 14 min.

[0092] The pressure in the fourth hot press is 530 kN; the temperature in the fourth hot press is 160 °C; and the time in the fourth hot press is 73 min.

[0093] The performance indicators of the obtained C-type pipes are detailed in Table 1.

[0094] Example 2

[0095] This embodiment provides a carbon fiber reinforced C-shaped tube. The C-shaped structure of the C-shaped tube includes an inner layer and an outer layer covering the inner layer. The outer layer is a first carbon fiber prepreg layer, and the inner layer is a second carbon fiber prepreg layer.

[0096] The carbon fiber content in the first carbon fiber prepreg layer is 208 g / m². 2 The carbon fiber content in the second carbon fiber prepreg layer is 375 g / m². 2 .

[0097] The tensile strength of the carbon fiber in the first carbon fiber prepreg layer is 1570 MPa; the tensile strength of the carbon fiber in the second carbon fiber prepreg layer is 2300 MPa; the tensile modulus of the carbon fiber in the first carbon fiber prepreg layer is 122 GPa; and the tensile modulus of the carbon fiber in the second carbon fiber prepreg layer is 144 GPa.

[0098] The resin content in the first carbon fiber prepreg layer is 44% by mass; the resin content in the second carbon fiber prepreg layer is 31% by mass. The thickness of the first carbon fiber prepreg layer is 0.27 mm; the thickness of the second carbon fiber prepreg layer is 0.35 mm.

[0099] The specific preparation process is as follows:

[0100] The core material is covered with the C-shaped structure, and then the first hot pressing, second hot pressing, third hot pressing and fourth hot pressing are performed in sequence. After that, the core material is removed to obtain carbon fiber reinforced C-shaped tube.

[0101] The pressure in the first hot press is 57 kN; the temperature in the first hot press is 142 °C; the time in the first hot press is 6 min.

[0102] The pressure in the second hot press is 108 kN; the temperature in the second hot press is 147 °C; and the time in the second hot press is 7 min.

[0103] The pressure in the third hot press is 360 kN; the temperature in the third hot press is 150 °C; and the time in the third hot press is 16 min.

[0104] The pressure in the fourth hot press is 510 kN; the temperature in the fourth hot press is 150 °C; and the time in the fourth hot press is 76 min.

[0105] Example 3

[0106] This embodiment provides a carbon fiber reinforced C-shaped tube. The C-shaped structure of the C-shaped tube includes an inner layer and an outer layer covering the inner layer. The outer layer is a first carbon fiber prepreg layer, and the inner layer is a second carbon fiber prepreg layer.

[0107] The carbon fiber content in the first carbon fiber prepreg layer is 200 g / m². 2 The carbon fiber content in the second carbon fiber prepreg layer is 400 g / m². 2 .

[0108] The tensile strength of the carbon fiber in the first carbon fiber prepreg layer is 1600 MPa; the tensile strength of the carbon fiber in the second carbon fiber prepreg layer is 2200 MPa; the tensile modulus of the carbon fiber in the first carbon fiber prepreg layer is 130 GPa; and the tensile modulus of the carbon fiber in the second carbon fiber prepreg layer is 150 GPa.

[0109] The first carbon fiber prepreg layer contains 45% resin by mass; the second carbon fiber prepreg layer contains 30% resin by mass. The first carbon fiber prepreg layer has a thickness of 0.28 mm; the second carbon fiber prepreg layer has a thickness of 0.34 mm.

[0110] The specific preparation process is as follows:

[0111] The core material is covered with the C-shaped structure, and then the first hot pressing, second hot pressing, third hot pressing and fourth hot pressing are performed in sequence. After that, the core material is removed to obtain carbon fiber reinforced C-shaped tube.

[0112] The pressure in the first hot press is 50 kN; the temperature in the first hot press is 140 °C; and the time in the first hot press is 5 min.

[0113] The pressure in the second hot press is 120 kN; the temperature in the second hot press is 160 °C; and the time in the second hot press is 5 min.

[0114] The pressure in the third hot press is 350 kN; the temperature in the third hot press is 140 °C; and the time in the third hot press is 20 min.

[0115] The pressure in the fourth hot press is 550 kN; the temperature in the fourth hot press is 170 °C; and the time in the fourth hot press is 80 min.

[0116] Example 4

[0117] This embodiment provides a carbon fiber reinforced C-shaped tube. The C-shaped structure of the C-shaped tube includes an inner layer and an outer layer covering the inner layer. The outer layer is a first carbon fiber prepreg layer, and the inner layer is a second carbon fiber prepreg layer.

[0118] The carbon fiber content in the first carbon fiber prepreg layer is 220 g / m². 2 The carbon fiber content in the second carbon fiber prepreg layer is 400 g / m². 2 .

[0119] The tensile strength of the carbon fiber in the first carbon fiber prepreg layer is 1500 MPa; the tensile strength of the carbon fiber in the second carbon fiber prepreg layer is 2500 MPa; the tensile modulus of the carbon fiber in the first carbon fiber prepreg layer is 110 GPa; and the tensile modulus of the carbon fiber in the second carbon fiber prepreg layer is 140 GPa.

[0120] The first carbon fiber prepreg layer contains 40% resin by mass; the second carbon fiber prepreg layer contains 33% resin by mass. The first carbon fiber prepreg layer has a thickness of 0.25 mm; the second carbon fiber prepreg layer has a thickness of 0.36 mm.

[0121] The specific preparation process is as follows:

[0122] The core material is covered with the C-shaped structure, and then the first hot pressing, second hot pressing, third hot pressing and fourth hot pressing are performed in sequence. After that, the core material is removed to obtain carbon fiber reinforced C-shaped tube.

[0123] The pressure in the first hot press is 60 kN; the temperature in the first hot press is 150 °C; and the time in the first hot press is 8 min.

[0124] The pressure in the second hot press is 100 kN; the temperature in the second hot press is 140 °C; the time in the second hot press is 10 min;

[0125] The pressure in the third hot pressing is 400 kN; the temperature in the third hot pressing is 155 °C; and the time in the third hot pressing is 10 min.

[0126] The pressure in the fourth hot pressing is 500 kN; the temperature in the fourth hot pressing is 140 °C; and the time in the fourth hot pressing is 70 min.

[0127] Example 5

[0128] The only difference from Example 1 is that the positions of the first carbon fiber prepreg layer and the second carbon fiber prepreg layer are interchanged, but the C-shaped structure remains unchanged. That is, the second carbon fiber prepreg layer covers the first carbon fiber prepreg layer.

[0129] Example 6

[0130] The only difference from Example 1 is that the first carbon fiber prepreg layer is replaced with the second carbon fiber prepreg layer.

[0131] Example 7

[0132] The only difference from Example 1 is that the second carbon fiber prepreg layer is replaced with the first carbon fiber prepreg layer.

[0133] Example 8

[0134] The only difference from Example 1 is that the resin content in the first carbon fiber prepreg is adjusted to 32%.

[0135] Example 9

[0136] The only difference from Example 1 is that the resin content in the second carbon fiber prepreg is adjusted to 42%.

[0137] Example 10

[0138] The only difference from Example 1 is that the thickness of the first carbon fiber prepreg layer is adjusted to 0.35 mm.

[0139] Example 11

[0140] The only difference from Example 1 is that the thickness of the second carbon fiber prepreg layer is adjusted to 0.26 mm.

[0141] Example 12

[0142] The only difference from Example 1 is that the first hot pressing is not performed.

[0143] Example 13

[0144] The only difference from Example 1 is that a second hot pressing is not performed.

[0145] Example 14

[0146] The only difference from Example 1 is that a third hot pressing is not performed.

[0147] Example 15

[0148] The only difference from Example 1 is that the fourth hot pressing is not performed.

[0149] In the above embodiments, the epoxy resin in the carbon fiber prepreg layer is LTC80 epoxy resin matrix, and the core material used is 304 stainless steel; the mechanical properties of the obtained C-shaped pipe are tested according to the national standard GT1447-2005I. During the test, since the carbon fibers on the surface of the C-shaped pipe are mutually perpendicular carbon fiber layers, the mechanical properties are tested along the perpendicular carbon fiber direction. If one carbon fiber is 0°, then the other perpendicular carbon fiber is recorded as 90°.

[0150] Table 1

[0151]

[0152]

[0153] In the table, NG indicates that it cannot be formed.

[0154] As can be seen from the results of the above embodiments, the C-shaped pipe provided by the present invention, through the design of the carbon fiber reinforced C-shaped pipe, can ensure that the C-shaped pipe is integrally formed, and the use of inner and outer layer design significantly improves the mechanical properties of the obtained carbon fiber reinforced C-shaped pipe, which is beneficial to improving the performance of the carbon fiber reinforced C-shaped pipe.

[0155] The present invention is described in detail through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0156] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0157] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0158] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A carbon fiber reinforced C-shaped tube, characterized in that, The C-shaped structure of the C-shaped tube includes an inner layer and an outer layer covering the inner layer. The outer layer is a first carbon fiber prepreg layer, and the inner layer is a second carbon fiber prepreg layer. The carbon fiber content in the first carbon fiber prepreg layer is less than the carbon fiber content in the second carbon fiber prepreg layer; The tensile strength of the carbon fibers in the first carbon fiber prepreg layer is less than the tensile strength of the carbon fibers in the second carbon fiber prepreg layer. The tensile modulus of the carbon fibers in the first carbon fiber prepreg layer is less than the tensile modulus of the carbon fibers in the second carbon fiber prepreg layer. The resin content in the first carbon fiber prepreg layer is greater than the resin content in the second carbon fiber prepreg layer; The thickness of the first carbon fiber prepreg layer is less than the thickness of the second carbon fiber prepreg layer.

2. The C-shaped pipe as described in claim 1, characterized in that, The carbon fiber content in the first carbon fiber prepreg layer is 200-220 g / m². 2 .

3. The C-shaped pipe as described in claim 1, characterized in that, The carbon fiber content in the second carbon fiber prepreg layer is 360-400 g / m². 2 .

4. The C-shaped pipe as described in claim 1, characterized in that, The tensile strength of the carbon fibers in the first carbon fiber prepreg layer is 1500-1600 MPa.

5. The C-shaped pipe as described in claim 1, characterized in that, The tensile strength of the carbon fibers in the second carbon fiber prepreg layer is 2200-2500 MPa.

6. The C-shaped pipe as described in claim 1, characterized in that, The tensile modulus of the carbon fibers in the first carbon fiber prepreg layer is 110-130 GPa.

7. The C-shaped pipe as described in claim 1, characterized in that, The tensile modulus of the carbon fibers in the second carbon fiber prepreg layer is 140-150 GPa.

8. The C-shaped pipe as described in claim 1, characterized in that, The resin content in the first carbon fiber prepreg layer is 40-45% by mass.

9. The C-shaped pipe as described in claim 1, characterized in that, The resin content in the second carbon fiber prepreg layer is 30-33% by mass.

10. The C-shaped pipe as described in claim 1, characterized in that, The thickness of the first carbon fiber prepreg layer is 0.25-0.28 mm.

11. The C-shaped pipe as described in claim 1, characterized in that, The thickness of the second carbon fiber prepreg layer is 0.34-0.36 mm.

12. A method for preparing a C-shaped pipe as described in any one of claims 1-11, characterized in that, The preparation method includes: coating the core material with the C-shaped structure, followed by sequential hot pressing, second hot pressing, third hot pressing and fourth hot pressing, and then removing the core material to obtain carbon fiber reinforced C-shaped tubing.

13. The preparation method according to claim 12, characterized in that, The pressure in the first hot press is 50-60 kN.

14. The preparation method according to claim 12, characterized in that, The temperature in the first hot press is 140-150℃.

15. The preparation method according to claim 12, characterized in that, The time for the first hot pressing is 5-8 minutes.

16. The preparation method according to claim 12, characterized in that, The pressure in the second hot pressing is 100-120kN.

17. The preparation method according to claim 12, characterized in that, The temperature in the second hot press is 140-160℃.

18. The preparation method according to claim 12, characterized in that, The second hot pressing time is 5-10 minutes.

19. The preparation method according to claim 12, characterized in that, The pressure in the third hot press is 350-400 kN.

20. The preparation method according to claim 12, characterized in that, The temperature in the third hot press is 140-155℃.

21. The preparation method according to claim 12, characterized in that, The time for the third hot pressing is 10-20 minutes.

22. The preparation method according to claim 12, characterized in that, The pressure in the fourth hot press is 500-550 kN.

23. The preparation method according to claim 12, characterized in that, The temperature in the fourth hot press is 140-170℃.

24. The preparation method according to claim 12, characterized in that, The time for the fourth hot pressing is 70-80 minutes.

25. The preparation method according to claim 12, characterized in that, The preparation method includes: coating the core material with the C-shaped structure, followed by sequential hot pressing, second hot pressing, third hot pressing and fourth hot pressing, and then removing the core material to obtain a carbon fiber reinforced C-shaped tube. The pressure in the first hot press is 50-60 kN; the temperature in the first hot press is 140-150 °C; and the time in the first hot press is 5-8 min. The pressure in the second hot pressing is 100-120 kN; the temperature in the second hot pressing is 140-160 °C; and the time in the second hot pressing is 5-10 min. The pressure in the third hot pressing is 350-400 kN; the temperature in the third hot pressing is 140-155 °C; and the time in the third hot pressing is 10-20 min. The pressure in the fourth hot pressing is 500-550 kN; the temperature in the fourth hot pressing is 140-170 °C; and the time in the fourth hot pressing is 70-80 min.

26. The use of the carbon fiber reinforced C-shaped tubing as described in any one of claims 1-11, characterized in that, The applications include using carbon fiber reinforced C-shaped tubing as support rods.

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