Composite steel plate and method for manufacturing the same, composite steel pipe and application

Abstract

The application relates to the technical field of pipeline production, and discloses a composite steel plate and a preparation method thereof, a composite steel pipe and application. The composite steel plate comprises a hydrogen permeation resistance layer and a reinforcing layer arranged on one side of the hydrogen permeation resistance layer; the material of the hydrogen permeation resistance layer and the reinforcing layer is pipeline steel, and the ratio of the yield strength of the hydrogen permeation resistance layer to the yield strength of the reinforcing layer is 1:(1.5-1.7). On this basis, the composite steel pipe is prepared through forming and welding of the composite steel plate. The composite steel pipe provided by the application adopts the composite steel plate obtained by composite rolling of specific low-grade pipeline steel and high-grade pipeline steel as pipe-making material, can well balance the hydrogen embrittlement resistance and the pipeline strength, and meets the application needs of large air volume, high efficiency and long-distance transportation of hydrogen energy.

Description

Composite steel plates and their preparation methods, composite steel pipes and their applications Technical Field

[0001] This invention relates to the field of pipeline manufacturing technology, specifically to a composite steel plate and its preparation method, composite steel pipe, and its application. Background Technology

[0002] Hydrogen energy, as an important chemical raw material, is widely used in petrochemical, metallurgical, and organic synthesis fields. In the industrial production and application of hydrogen energy, specifically, during the production stage, the hydrogen generated in the hydrogen generator needs to be transported to a hydrogen storage device; during the utilization stage, the hydrogen in the storage device needs to be transported to the production unit or energy conversion unit for use. Conventional hydrogen energy transportation equipment is long-tube trailers. This method is limited by short transport distances and low transport capacity, making it increasingly difficult to meet usage needs. Pipeline transportation, compared to long-tube trailers, has significant advantages such as larger transport capacity and lower energy consumption, and is expected to become a replacement for the former.

[0003] Currently, long-distance hydrogen pipelines are not yet widely used in the market. The total length of hydrogen pipelines worldwide is only about 4,600 km, with the United States having the largest scale, reaching 2,720 km. Most current hydrogen pipelines use seamless steel pipes, with hydrogen transmission pressures typically ranging from 2 to 10 MPa. The pipe material is mainly low-strength pipeline steel, and due to manufacturing limitations, the pipe diameter is small (usually <610 mm inner diameter), resulting in low hydrogen transmission efficiency and high pipeline construction costs. To date, large-volume, long-distance transportation has not been achieved, significantly limiting the application of pipeline hydrogen transport.

[0004] Therefore, developing a new type of hydrogen pipeline that combines excellent resistance to hydrogen embrittlement with pipeline strength is of great significance for realizing large-volume, efficient, and long-distance transportation of hydrogen energy. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem that existing hydrogen transport pipelines cannot meet the requirements of large volume, high efficiency, and long distance transportation, and to provide a composite steel plate, its preparation method, composite steel pipe, and its application.

[0006] To achieve the above objectives, the first aspect of the present invention provides a composite steel plate, the composite steel plate comprising a hydrogen permeation resistant layer and a reinforcing layer disposed on one side of the hydrogen permeation resistant layer;

[0007] The hydrogen permeation resistant layer and the reinforcing layer are made of pipeline steel, and the ratio of the yield strength of the hydrogen permeation resistant layer to the yield strength of the reinforcing layer is 1:(1.5-1.7).

[0008] A second aspect of the present invention provides a method for preparing a composite steel plate, comprising:

[0009] (1) The first steel billet and the second steel billet are stacked and welded together to obtain a composite billet;

[0010] (2) The composite billet is rolled and cut to obtain a composite steel plate;

[0011] The first and second steel billets are made of pipeline steel.

[0012] In the composite steel plate, the ratio of the yield strength of the hydrogen permeation resistant layer formed by the first steel billet to the yield strength of the reinforcing layer formed by the second steel billet is 1:(1.5-1.7).

[0013] A third aspect of the present invention provides a composite steel plate obtained by the method described in the second aspect above.

[0014] The fourth aspect of the present invention provides a composite steel pipe, which is obtained by forming and welding the composite steel plate described in the first or third aspect above;

[0015] The inner wall of the composite steel pipe is the hydrogen permeation resistant layer of the composite steel plate, and the outer wall of the composite steel pipe is the reinforcing layer of the composite steel plate.

[0016] The fifth aspect of this invention provides the application of the composite steel pipe described in the fourth aspect above in the field of hydrogen energy transportation.

[0017] Through the above technical solution, the present invention can achieve the following beneficial effects:

[0018] (1) The composite steel pipe provided by the present invention uses a composite steel plate made of specific low-grade pipeline steel and high-grade pipeline steel as the pipe material, which can well balance the resistance to hydrogen embrittlement and the strength of the pipeline, and meet the application needs of large volume, high efficiency, long distance and high pressure transportation of hydrogen energy.

[0019] (2) The manufacturing process is simple, feasible, and cost-saving. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0021] Figure 1 is a schematic diagram (side view) of the layer structure of the composite steel plate provided by the present invention.

[0022] Figure 2 is a process flow diagram of a composite steel plate preparation process provided by the present invention.

[0023] Figure 3 is a schematic cross-sectional view of the composite steel pipe provided by the present invention.

[0024] Figure 4 is a process flow diagram of the preparation of composite steel pipe provided by the present invention.

[0025] Explanation of reference numerals in the attached figures

[0026] 1- Hydrogen permeation resistant layer; 2- Reinforcing layer; 3- Inner wall of composite steel pipe

[0027] 4-Outer wall of composite steel pipe; 5-Inner wall weld of composite steel plate; 6-Outer wall weld of composite steel plate Detailed Implementation

[0028] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0029] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0030] The first aspect of the present invention provides a composite steel plate, the composite steel plate including a hydrogen permeation resistant layer and a reinforcing layer disposed on one side of the hydrogen permeation resistant layer;

[0031] The hydrogen permeation resistant layer and the reinforcing layer are made of pipeline steel, and the ratio of the yield strength of the hydrogen permeation resistant layer to the yield strength of the reinforcing layer is 1:(1.5-1.7).

[0032] The composite steel plate provided by this invention has a composite layer structure, as shown in Figure 1. The composite steel plate includes a hydrogen permeation resistant layer 1 and a reinforcing layer 2, wherein the reinforcing layer 2 is disposed on any one of the two sides of the hydrogen permeation resistant layer 1. The hydrogen permeation resistant layer 1 has hydrogen embrittlement resistance, while the reinforcing layer 2 has high strength. The composite steel plate adopts a composite method of "same material type + different material grade" between different layer structures. Specifically, both the hydrogen permeation resistant layer 1 and the reinforcing layer 2 are made of pipeline steel, and the steel grade of the pipeline steel used in the hydrogen permeation resistant layer 1 is lower than that of the pipeline steel used in the reinforcing layer 2. Further, the ratio of the yield strength of the hydrogen permeation resistant layer 1 to the yield strength of the reinforcing layer 2 is 1:(1.5-1.7). The composite steel plate provided by this invention has the above-mentioned layer structure and layer function, and can combine excellent hydrogen embrittlement resistance, mechanical properties, and processing performance.

[0033] According to the present invention, the hydrogen permeation resistant layer 1 has a hydrogen embrittlement resistance function. In the present invention, "hydrogen embrittlement" refers to the phenomenon where, during long-term contact with hydrogen gas, hydrogen atoms diffuse and enter the metal lattice of the steel material, where hydrogen atoms aggregate into hydrogen molecules, causing stress concentration that exceeds the strength limit of the steel material, forming fine cracks inside the steel material, thereby deteriorating the mechanical properties of the steel material, leading to embrittlement or even cracking.

[0034] According to the present invention, in the composite steel plate, the material of the hydrogen permeation resistant layer 1 can be selected from low-grade pipeline steel, preferably at least one of L290 pipeline steel, L320 pipeline steel, L360 pipeline steel, and L390 pipeline steel. By satisfying the above material requirements, the hydrogen permeation resistant layer 1 can possess excellent resistance to hydrogen embrittlement and meet processing and certain pressure-bearing requirements in terms of mechanical properties.

[0035] According to the present invention, in the composite steel plate, the material of the reinforcing layer 2 can be selected from high-grade pipeline steel, preferably L485 pipeline steel and / or L555 pipeline steel. By satisfying the above material requirements, the reinforcing layer 2 can possess excellent mechanical properties, especially excellent strength and pressure-bearing capacity.

[0036] In this invention, the L290 pipeline steel, L320 pipeline steel, L360 pipeline steel, L390 pipeline steel, L485 pipeline steel, and L555 pipeline steel refer to the pipeline steel materials specified in GB / T 9711-2017 (Steel Pipes for Pipeline Transportation Systems in the Oil and Gas Industry), where "L" stands for "Pipeline," and the number after "L" indicates the yield strength. The pipeline steel of the above specifications can be obtained through conventional methods, either self-manufactured or commercially purchased.

[0037] According to the present invention, in the composite steel plate, the thickness of the hydrogen permeation resistant layer 1 can be 3-5 mm. If the thickness of the hydrogen permeation resistant layer 1 is too small, it will result in insufficient resistance to hydrogen permeation; if the thickness of the hydrogen permeation resistant layer 1 is too large, it will result in insufficient overall structural strength of the composite steel plate.

[0038] According to the present invention, preferably, the thickness of the hydrogen permeation resistant layer 1 is 3.5-4.5 mm. For example, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm, 3.9 mm, 4.0 mm, 4.1 mm, 4.2 mm, 4.3 mm, 4.4 mm, 4.5 mm, and any value within the range of any two of the above values.

[0039] According to the present invention, in the composite steel plate, the thickness of the reinforcing layer 2 can be 10-30 mm. If the thickness of the reinforcing layer 2 is too small, the overall structural strength of the composite steel plate will be insufficient; if the thickness of the reinforcing layer 2 is too large, it will affect the composite steel plate's ability to resist hydrogen permeation.

[0040] According to the present invention, preferably, the thickness of the reinforcing layer 2 is 16.5-17.5 mm, for example 16.5 mm, 16.6 mm, 16.7 mm, 16.8 mm, 16.9 mm, 17.0 mm, 17.1 mm, 17.2 mm, 17.3 mm, 17.4 mm, 17.5 mm, and any value within the range of any two of the above values.

[0041] According to the present invention, in the composite steel plate, the hydrogen permeation resistant layer 1 and the reinforcing layer 2, on the basis of each satisfying the above-mentioned thickness limitation, preferably have a thickness ratio of 1:(3-10) for the hydrogen permeation resistant layer 1 and the reinforcing layer 2, thereby enabling the composite steel plate to have better hydrogen embrittlement resistance, mechanical properties and processing properties.

[0042] According to the present invention, in the composite steel plate, the hydrogen permeation resistant layer 1 and the reinforcing layer 2 are composited by welding.

[0043] According to the present invention, the tensile property loss rate of the composite steel plate is ≤4%, and it has excellent resistance to hydrogen embrittlement.

[0044] According to the present invention, the composite steel plate has a yield strength ≥435MPa, more preferably 500-625MPa, and has excellent strength and compressive strength.

[0045] A second aspect of the present invention provides a method for preparing a composite steel plate, comprising:

[0046] (1) The first steel billet and the second steel billet are stacked and welded together to obtain a composite billet;

[0047] (2) The composite billet is rolled and cut to obtain a composite steel plate;

[0048] The first and second steel billets are made of pipeline steel.

[0049] In the composite steel plate, the ratio of the yield strength of the hydrogen permeation resistant layer formed by the first steel billet to the yield strength of the reinforcing layer formed by the second steel billet is 1:(1.5-1.7).

[0050] According to the present invention, in step (1), the material of the first steel billet can be selected from low-grade pipeline steel, preferably at least one of L290 pipeline steel, L320 pipeline steel, L360 pipeline steel and L390 pipeline steel.

[0051] According to the present invention, in step (1), the material of the reinforcing layer 2 can be selected from high-grade pipeline steel, preferably L485 pipeline steel and / or L555 pipeline steel.

[0052] According to the present invention, in step (1), the lamination process preferably involves first processing the first steel billet and the second steel billet to the same size, and then grinding the surfaces to be laminated, and finally bringing the surfaces to be laminated into complete contact to achieve lamination.

[0053] According to the present invention, in step (1), the welding is preferably performed by vacuum electron beam welding, which can achieve better welding strength.

[0054] According to the present invention, the conditions for vacuum electron beam welding include: vacuum degree ≤ 5 × 10⁻⁶. -2 Pa; welding current is 20-60mA, welding voltage is 40-60kV, and welding speed is 0.6-1.2m / min.

[0055] According to the present invention, in step (2), the rolling includes roughing and finishing.

[0056] The initial rolling temperature of the roughing mill is 1175-1225℃, and the final rolling temperature is 885-915℃.

[0057] The initial rolling temperature of the finishing mill is 825-875℃, and the final rolling temperature is 785-815℃.

[0058] According to this method, preferably, in the composite steel plate, the thickness of the hydrogen permeation resistant layer formed from the first steel billet is 3-5 mm.

[0059] According to this method, preferably, in the composite steel plate, the thickness of the reinforcing layer formed by the second steel billet is 10-30 mm.

[0060] In this invention, the method for preparing the composite steel plate includes the above-mentioned steps (1) and (2). Specifically, according to a preferred embodiment of this invention, the method for preparing the composite steel plate can be implemented using the process flow shown in Figure 2:

[0061] (1-1) The first steel billet (thickness of 3-5mm) and the second steel billet (thickness of 10-30mm) are subjected to raw material pretreatment. The raw material pretreatment includes cutting the first steel billet and the second steel billet into the same size and grinding the surfaces to be composited.

[0062] (1-2) The surfaces of the first and second steel billets, after the raw material pretreatment, are brought into contact so that the first and second steel billets are completely stacked to form a weldable billet. Welding is then performed to obtain the composite billet. In practice, one sheet of each of the first and second steel billets can be stacked, or multiple sheets can be stacked. Multiple sheets are preferred. For example, two sheets of each of the first and second steel billets are stacked from bottom to top in the order of "second steel billet → first steel billet → first steel billet → second steel billet." During the stacking process, a high-temperature resistant insulating agent is injected between adjacent sheets of the first steel billet. The composite billet obtained using this stacking method contains two sets of "first steel billet + second steel billet," ensuring the symmetry of the rolling stress and thus guaranteeing the uniformity of the rolling deformation and the dimensional accuracy of the final composite steel plate. The welding is preferably performed using vacuum electron beam welding (welding conditions include: vacuum degree ≤ 5 × 10⁻⁶). -2 Pa; welding current is 20-60mA, welding voltage is 40-60kV, and welding speed is 0.6-1.2m / min);

[0063] (1-3) The composite billet is heated to 1150-1250℃ and held for 2-6 hours. The heat treatment can ensure the uniformity of the overall temperature of the rolled billet. Then the composite billet is descaled, preferably by high-pressure water descaling.

[0064] (2-1) The dephosphorized composite billet is symmetrically rolled, specifically, rough rolling (the initial rolling temperature of rough rolling is 1175-1225℃, and the final rolling temperature is 885-915℃) and finish rolling (the initial rolling temperature of finish rolling is 825-875℃, and the final rolling temperature is 785-815℃) are performed in sequence, and the rolled plate is cooled and hot straightened to obtain the rolled part;

[0065] (2-2) The rolled part is heated to 450-550℃ and held for 1-2 hours. The heat treatment can eliminate the stress between the composite layers in the rolled part and improve the resistance to intergranular corrosion. Then the rolled part is pre-cut and separated. The pre-cut and separation can achieve the initial control of the product size. For the case of multiple sets of stacking in step (1-2), the multiple sets of "first steel plate + second steel plate" in the rolled part can also be separated by pre-cut and separation to obtain multiple composite steel plate pre-products (for the case of stacking one first steel billet and one second steel billet in step (1-2), the corresponding result here is one composite steel plate pre-product). Then the composite steel plate pre-product is cold straightened and ultrasonically tested to obtain a rough product.

[0066] (2-3) The rough product is sequentially subjected to fine shearing, fine straightening and surface treatment to obtain a composite steel plate; the obtained composite steel plate includes a hydrogen permeation resistant layer and a reinforcing layer disposed on one side of the hydrogen permeation resistant layer; wherein the material of the hydrogen permeation resistant layer and the reinforcing layer is pipeline steel, and the ratio of the yield strength of the hydrogen permeation resistant layer to the yield strength of the reinforcing layer is 1:(1.5-1.7); the thickness of the hydrogen permeation resistant layer is 3-5mm, and the thickness of the reinforcing layer is 10-30mm.

[0067] A third aspect of the present invention provides a composite steel plate obtained by the method described in the second aspect above.

[0068] According to the present invention, the structure and properties of the composite steel plate obtained by the method described in the second aspect are the same as those of the composite steel plate described in the first aspect of the present invention, and will not be repeated here.

[0069] The fourth aspect of the present invention provides a composite steel pipe, which is obtained by forming and welding the composite steel plate described in the first or third aspect above;

[0070] As shown in Figure 3, the inner wall 3 of the composite steel pipe is the hydrogen permeation resistant layer of the composite steel plate, and the outer wall 4 of the composite steel pipe is the reinforcing layer of the composite steel plate.

[0071] According to the present invention, in the method for preparing the composite steel pipe, conventional straight seam steel pipe forming, welding processes and parameters can be used for pipe making and welding. Preferably, JCOE (straight seam double-sided submerged arc welded pipe) process is used for pipe making and welding. More preferably, low-grade welding wire is used in the inner welding process of the welding process. Specifically, the low-grade welding wire is required to obtain a composite steel plate inner wall weld 5 with pearlite structure as the main component after welding, so that the strength of the composite steel plate inner wall weld 5 is comparable to the strength of the hydrogen permeation resistant layer in the composite steel plate. In the outer welding process, high-grade welding wire is used, and the high-grade welding wire is required to obtain a composite steel plate outer wall weld 6 with ferrite structure as the main component after welding, so that the strength of the composite steel plate outer wall weld 6 is comparable to the strength of the reinforcing layer in the composite steel plate.

[0072] According to a preferred embodiment of the present invention, the method for preparing the composite steel pipe can be implemented using the process flow shown in Figure 4:

[0073] (I) Ultrasonic Plate Inspection: The composite steel plate is subjected to full-plate ultrasonic testing to ensure that there are no defects exceeding [a certain threshold] inside the composite steel plate. (i.e., a layered defect of equivalent size to a 6mm diameter flat-bottomed hole);

[0074] (II) Milling: The two edges of the composite steel plate are milled using a milling machine to achieve the target plate width, plate edge parallelism and bevel shape;

[0075] (III) Pre-bending: The composite steel plate after milling is pre-bent using a pre-bending machine to ensure that the inner diameter chord height within 150mm of the plate edge meets the corresponding pipe diameter size, so as to ensure the curvature of the pipe body.

[0076] (IV) Forming: The pre-bent composite steel plate is stamped and bent using a JCOE forming machine to form a tube with an "O" shaped opening;

[0077] (V) Pre-welding: The formed tube body is joined together and continuously welded;

[0078] (VI) Inner welding: The inner side of the pipe body is welded using submerged arc welding (welding conditions include: welding current of 500-1000A, welding voltage of 30-42V, and welding speed of 1.35-1.7m / min); the welding wire used shall produce a weld structure dominated by pearlite after welding, so that the strength of the weld is comparable to the strength of the hydrogen permeation resistant layer in the composite steel plate. For example, H08MnA welding wire can be used.

[0079] (VII) External welding: The outer side of the pipe body is welded using submerged arc welding (welding conditions include: welding current of 500-1000A, welding voltage of 30-42V, and welding speed of 1.35-1.7m / min); the welding wire used shall obtain a weld structure dominated by ferrite after welding, so that the strength of the weld is comparable to the strength of the reinforcing layer in the composite steel plate. For example, H08MnMoTiB welding wire can be used.

[0080] (VIII) First ultrasonic test: Inspect the inner and outer welds of the pipe body and both sides of the welds;

[0081] (IX) First X-ray television inspection: X-ray industrial television inspection of the inner and outer welds of the tube body;

[0082] (X) Mechanical expansion: The diameter of the pipe is expanded along its entire length to improve the dimensional accuracy of the pipe and improve the distribution of stress within the pipe.

[0083] (XI) Flat end: The two end faces of the pipe body are machined to ensure the sealing effect of the subsequent water pressure test;

[0084] (XII) Hydrostatic test: The mechanically enlarged pipe body is inspected using a hydrostatic testing machine to ensure that it meets the allowable pressure required by the steel grade specified in GB / T9711;

[0085] (XIII) Beveling: After the water pressure test is passed, the pipe end is processed to achieve the target pipe end bevel size;

[0086] (XIV) Second ultrasonic test: Perform ultrasonic testing on the pipe body again to check for defects that may occur after mechanical expansion and hydrostatic testing.

[0087] (XV) Second X-ray television inspection: Take X-rays or extract DR digital images of the weld area with a length of not less than 250mm at the pipe end for inspection.

[0088] (XVI) Finished product inspection.

[0089] According to the present invention, preferably, the inner diameter of the composite steel pipe can be 400-1500 mm.

[0090] According to the present invention, the tensile property loss rate of the composite steel pipe is <5%.

[0091] According to the present invention, the yield strength of the composite steel pipe is ≥435MPa, and more preferably 500-625MPa.

[0092] In this invention, the tensile property loss rate and yield strength of the composite steel plate and composite steel pipe are determined according to the method specified in GB / T34542-2018.

[0093] The composite steel pipe provided by this invention uses a composite steel plate made by composite rolling of specific low-grade pipeline steel and high-grade pipeline steel as the pipe material. It can well balance hydrogen embrittlement resistance and pipeline strength, and can be used for high-volume, high-efficiency, long-distance high-pressure transportation of hydrogen energy. Moreover, the manufacturing process is simple and easy to implement.

[0094] The fifth aspect of this invention provides the application of the composite steel pipe described in the fourth aspect above in the field of hydrogen energy transportation.

[0095] The present invention will be described in detail below through embodiments. Unless otherwise specified, all materials used in the following embodiments are commercially available products.

[0096] Example 1

[0097] Preparation of composite steel plates:

[0098] (1-1) The first steel billet (material L290, thickness 15mm) and the second steel billet (L485, thickness 80mm) are subjected to raw material pretreatment. The raw material pretreatment includes cutting the first steel billet and the second steel billet into the same size and grinding the surfaces to be composited.

[0099] (1-2) The surfaces of the first and second steel billets, after raw material pretreatment, are brought into contact to completely overlap and combine them into a weldable billet. Welding is then performed to obtain the composite billet. Multiple sheets are stacked: two sheets of each of the first and second steel billets are taken and stacked from bottom to top in the order of "second steel billet → first steel billet → first steel billet → second steel billet". During the stacking process, a high-temperature resistant insulating agent is injected between adjacent first steel billets to prevent them from rolling together later. Vacuum electron beam welding is used (welding conditions include: vacuum degree of 4.5 × 10⁻⁶). -2 Pa; welding current is 50mA, welding voltage is 50kV, welding speed is 0.6m / min), welding is performed along the contact line between the first steel billet and the second steel billet in the blank to be welded to achieve fixation;

[0100] (1-3) Heat the composite blank to 1200℃ and keep it at that temperature for 4 hours, then descale it.

[0101] (2-1) The composite billet after dephosphorization is subjected to rough rolling (starting rolling temperature is 1175-1225℃, finishing rolling temperature is 885-915℃) and finish rolling (starting rolling temperature is 825-875℃, finishing rolling temperature is 785-815℃), and the rolled plate is cooled and hot straightened to obtain the rolled part.

[0102] (2-2) The rolled part is heated to 550℃ and held for 1 hour. Then the rolled part is pre-cut and separated. The product size is initially controlled by the pre-cut and separation. Due to the presence of the release agent, when the edges of the rolled part are cut, the two sets of "first steel billet + second steel billet" naturally separate to obtain two composite steel plate pre-products. Then the composite steel plate pre-products are cold straightened and ultrasonically tested to obtain the rough product.

[0103] (2-3) The rough product is sequentially subjected to fine shearing, fine straightening and surface treatment to obtain a composite steel plate (denoted as S1);

[0104] S1 has a hydrogen permeation resistant layer and a reinforcing layer is provided on one side of the hydrogen permeation resistant layer; wherein, the thickness of the hydrogen permeation resistant layer is 3mm and the thickness of the reinforcing layer is 17.5mm; the ratio of the yield strength of the hydrogen permeation resistant layer to the yield strength of the reinforcing layer is 1:1.6.

[0105] The tensile property loss rate of composite steel plate S1 is 3.5%, and the yield strength is 500 MPa.

[0106] Composite pipes are made using composite steel plate S1:

[0107] (I) Ultrasonic Plate Inspection: The composite steel plate S1 described above undergoes full-plate ultrasonic testing to ensure that there are no defects exceeding [a certain threshold] inside the composite steel plate. Delamination defects of equivalent size to flat-bottomed holes;

[0108] (II) Milling: Use a milling machine to mill the two edges of the composite steel plate to achieve the target plate width, plate edge parallelism and bevel shape;

[0109] (III) Pre-bending: The composite steel plate after milling is pre-bent using a pre-bending machine to ensure that the inner diameter chord height within 150mm of the plate edge meets the corresponding pipe diameter size, so as to ensure the curvature of the pipe body.

[0110] (IV) Forming: The pre-bent composite steel plate is stamped and bent using a JCOE forming machine to form a tube with an "O" shaped opening;

[0111] (V) Pre-welding: The formed tube body is joined together and continuously welded;

[0112] (VI) Inner Welding: The inner side of the pipe body is welded using submerged arc welding (using three welding wires: the first welding wire has a welding current of 850A and a welding voltage of 32V; the second welding wire has a welding current of 600A and a welding voltage of 36V; the third welding wire has a welding current of 500A and a welding voltage of 38V; the welding speed is 1.5m / min for all three welding wires). All three welding wires are H08MnA welding wires. After welding, a weld structure dominated by pearlite is obtained, making the strength of the weld comparable to the strength of the hydrogen permeation resistant layer in the composite steel plate.

[0113] (VII) External Welding: The outer side of the pipe body is welded using submerged arc welding (using four welding wires; the welding current of the first welding wire is 1000A and the welding voltage is 32V; the welding current of the second welding wire is 850A and the welding voltage is 36V; the welding current of the third welding wire is 600A and the welding voltage is 38V; the welding current of the fourth welding wire is 500A and the welding voltage is 40V; the welding speed is 1.6m / min for all four welding wires). H08MnMoTiB welding wire is used for all four welding wires. After welding, a weld structure dominated by ferrite is obtained, so that the strength of the weld is comparable to the strength of the reinforcing layer in the composite steel plate.

[0114] (VIII) First ultrasonic test: Inspect the inner and outer welds of the pipe body and both sides of the welds;

[0115] (IX) First X-ray television inspection: The inner and outer welds of the pipe body are inspected by X-ray industrial television. A fixed X-ray equipment with single-wall single-image method (equipped with DR flat plate device) is used to conduct 100% full weld radiographic inspection of the pipe body, mainly to find volumetric defects.

[0116] (X) Mechanical expansion: The diameter of the pipe is expanded along its entire length to improve the dimensional accuracy of the pipe and improve the distribution of stress within the pipe.

[0117] (XI) Flat end: The two end faces of the pipe body are machined to ensure the sealing effect of the subsequent water pressure test;

[0118] (XII) Hydrostatic test: The mechanically enlarged pipe body is inspected using a hydrostatic testing machine to ensure that it meets the allowable pressure required by the steel grade specified in GB / T9711;

[0119] (XIII) Beveling: After the water pressure test is passed, the pipe end is processed to achieve the target pipe end bevel size;

[0120] (XIV) Second ultrasonic test: Perform ultrasonic testing on the pipe body again to check for defects that may occur after mechanical expansion and hydrostatic testing.

[0121] (XV) Second X-ray television inspection: DR digital image extraction inspection of the weld area with a length of not less than 250mm at the pipe end;

[0122] (XVI) Finished product inspection, to obtain the finished composite steel pipe (denoted as T1).

[0123] T1 has an inner diameter of 780 mm; its tensile strength loss rate is 3.5%, and its yield strength is 500 MPa, which can meet the requirements for high-volume, high-efficiency, long-distance, high-pressure transportation of hydrogen energy.

[0124] Example 2

[0125] Preparation of composite steel plates:

[0126] (1-1) The first steel billet (material L290, thickness 15mm) and the second steel billet (L555, thickness 80mm) are subjected to raw material pretreatment. The raw material pretreatment includes cutting the first steel billet and the second steel billet into the same size and grinding the surfaces to be composited.

[0127] (1-2) The surfaces of the first and second steel billets, after raw material pretreatment, are brought into contact to completely overlap and combine them into a weldable billet. Welding is then performed to obtain the composite billet. Multiple sheets are stacked: two sheets of each of the first and second steel billets are taken and stacked from bottom to top in the order of "second steel billet → first steel billet → first steel billet → second steel billet". During the stacking process, a high-temperature resistant insulating agent is injected between adjacent first steel billets to prevent them from rolling together later. Vacuum electron beam welding is used (welding conditions include: vacuum degree of 4.5 × 10⁻⁶). -2 Pa; welding current is 50mA, welding voltage is 50kV, welding speed is 0.6m / min), welding is performed along the contact line between the first steel billet and the second steel billet in the blank to be welded to achieve fixation;

[0128] (1-3) Heat the composite blank to 1180℃ and keep it at that temperature for 4 hours, then descale it.

[0129] (2-1) The composite billet after dephosphorization is subjected to rough rolling (starting rolling temperature is 1175-1225℃, finishing rolling temperature is 885-915℃) and finish rolling (starting rolling temperature is 825-875℃, finishing rolling temperature is 785-815℃), and the rolled plate is cooled and hot straightened to obtain the rolled part.

[0130] (2-2) The rolled part is heated to 550℃ and held for 1 hour. Then the rolled part is pre-cut and separated. The product size is initially controlled by the pre-cut and separation. Due to the presence of the release agent, when the edges of the rolled part are cut, the two sets of "first steel billet + second steel billet" naturally separate to obtain two composite steel plate pre-products. Then the composite steel plate pre-products are cold straightened and ultrasonically tested to obtain the rough product.

[0131] (2-3) The rough product is sequentially subjected to fine shearing, fine straightening and surface treatment to obtain a composite steel plate (denoted as S2);

[0132] S2 has a hydrogen permeation resistant layer and a reinforcing layer on one side of the hydrogen permeation resistant layer; wherein, the thickness of the hydrogen permeation resistant layer is 3mm and the thickness of the reinforcing layer is 15mm; the ratio of the yield strength of the hydrogen permeation resistant layer to the yield strength of the reinforcing layer is 1:1.66.

[0133] The tensile strength loss rate of composite steel plate S2 is 4%, and the yield strength is 550 MPa.

[0134] Composite pipes are made using composite steel plate S2:

[0135] (I) Ultrasonic Plate Inspection: The composite steel plate S2 described above undergoes full-plate ultrasonic testing to ensure that there are no defects exceeding [a certain threshold] inside the composite steel plate. Delamination defects of equivalent size to flat-bottomed holes;

[0136] (II) Milling: Use a milling machine to mill the two edges of the composite steel plate to achieve the target plate width, plate edge parallelism and bevel shape;

[0137] (III) Pre-bending: The composite steel plate after milling is pre-bent using a pre-bending machine to ensure that the inner diameter chord height within 150mm of the plate edge meets the corresponding pipe diameter size, so as to ensure the curvature of the pipe body.

[0138] (IV) Forming: The pre-bent composite steel plate is stamped and bent using a JCOE forming machine to form a tube with an "O" shaped opening;

[0139] (V) Pre-welding: The formed tube body is joined together and continuously welded;

[0140] (VI) Inner Welding: The inner side of the pipe body is welded using submerged arc welding (using three welding wires: the first welding wire has a welding current of 850A and a welding voltage of 32V; the second welding wire has a welding current of 600A and a welding voltage of 36V; the third welding wire has a welding current of 500A and a welding voltage of 38V; the welding speed is 1.5m / min for all three welding wires). All three welding wires are H08MnA welding wires. After welding, a weld structure dominated by pearlite is obtained, making the strength of the weld comparable to the strength of the hydrogen permeation resistant layer in the composite steel plate.

[0141] (VII) External Welding: The outer side of the pipe body is welded using submerged arc welding (using four welding wires; the welding current of the first welding wire is 1000A and the welding voltage is 32V; the welding current of the second welding wire is 850A and the welding voltage is 36V; the welding current of the third welding wire is 600A and the welding voltage is 38V; the welding current of the fourth welding wire is 500A and the welding voltage is 40V; the welding speed is 1.6m / min for all four welding wires). H08MnMoTiB welding wire is used for all four welding wires. After welding, a weld structure dominated by ferrite is obtained, so that the strength of the weld is comparable to the strength of the reinforcing layer in the composite steel plate.

[0142] (VIII) First ultrasonic test: Inspect the inner and outer welds of the pipe body and both sides of the welds;

[0143] (IX) First X-ray television inspection: The inner and outer welds of the pipe body are inspected by X-ray industrial television. A fixed X-ray equipment with single-wall single-image method (equipped with DR flat plate device) is used to conduct 100% full weld radiographic inspection of the pipe body, mainly to find volumetric defects.

[0144] (X) Mechanical expansion: The diameter of the pipe is expanded along its entire length to improve the dimensional accuracy of the pipe and improve the distribution of stress within the pipe.

[0145] (XI) Flat end: The two end faces of the pipe body are machined to ensure the sealing effect of the subsequent water pressure test;

[0146] (XII) Hydrostatic test: The mechanically enlarged pipe body is inspected using a hydrostatic testing machine to ensure that it meets the allowable pressure required by the steel grade specified in GB / T9711;

[0147] (XIII) Beveling: After the water pressure test is passed, the pipe end is processed to achieve the target pipe end bevel size;

[0148] (XIV) Second ultrasonic test: Perform ultrasonic testing on the pipe body again to check for defects that may occur after mechanical expansion and hydrostatic testing.

[0149] (XV) Second X-ray television inspection: DR digital image extraction inspection of the weld area with a length of not less than 250mm at the pipe end;

[0150] (XVI) Finished product inspection, the composite steel pipe finished product is obtained (denoted as T2).

[0151] T2 has an inner diameter of 980 mm; its tensile strength loss rate is 4%, and its yield strength is 550 MPa, which can meet the requirements for high-volume, high-efficiency, long-distance, high-pressure transportation of hydrogen energy.

[0152] Example 3

[0153] Preparation of composite steel plates:

[0154] (1-1) The first steel billet (material L360, thickness 15mm) and the second steel billet (L485, thickness 80mm) are subjected to raw material pretreatment. The raw material pretreatment includes cutting the first steel billet and the second steel billet into the same size and grinding the surfaces to be composited.

[0155] (1-2) The surfaces of the first and second steel billets, after raw material pretreatment, are brought into contact to completely overlap and combine them into a weldable billet. Welding is then performed to obtain the composite billet. Multiple sheets are stacked: two sheets of each of the first and second steel billets are taken and stacked from bottom to top in the order of "second steel billet → first steel billet → first steel billet → second steel billet". During the stacking process, a high-temperature resistant insulating agent is injected between adjacent first steel billets to prevent them from rolling together later. Vacuum electron beam welding is used (welding conditions include: vacuum degree of 4.5 × 10⁻⁶). -2 Pa; welding current is 50mA, welding voltage is 50kV, welding speed is 0.6m / min), welding is performed along the contact line between the first steel billet and the second steel billet in the blank to be welded to achieve fixation;

[0156] (1-3) Heat the composite blank to 1180℃ and keep it at that temperature for 4 hours, then descale it.

[0157] (2-1) The composite billet after dephosphorization is subjected to rough rolling (starting rolling temperature is 1175-1225℃, finishing rolling temperature is 885-915℃) and finish rolling (starting rolling temperature is 825-875℃, finishing rolling temperature is 785-815℃), and the rolled plate is cooled and hot straightened to obtain the rolled part.

[0158] (2-2) The rolled part is heated to 550℃ and held for 1 hour. Then the rolled part is pre-cut and separated. The product size is initially controlled by the pre-cut and separation. Due to the presence of the release agent, when the edges of the rolled part are cut, the two sets of "first steel billet + second steel billet" naturally separate to obtain two composite steel plate pre-products. Then the composite steel plate pre-products are cold straightened and ultrasonically tested to obtain the rough product.

[0159] (2-3) The rough product is sequentially subjected to fine shearing, fine straightening and surface treatment to obtain a composite steel plate (denoted as S3);

[0160] S3 has a hydrogen permeation resistant layer and a reinforcing layer on one side of the hydrogen permeation resistant layer; wherein, the thickness of the hydrogen permeation resistant layer is 4 mm and the thickness of the reinforcing layer is 17 mm; the ratio of the yield strength of the hydrogen permeation resistant layer to the yield strength of the reinforcing layer is 1:1.5.

[0161] The tensile strength loss rate of composite steel plate S3 is 3.5%, and the yield strength is 500 MPa.

[0162] Composite pipes are made using S3 composite steel plates:

[0163] (I) Ultrasonic Plate Inspection: The composite steel plate S3 described above undergoes a full-plate ultrasonic inspection to ensure that there are no defects exceeding [a certain threshold] inside the composite steel plate. Delamination defects of equivalent size to flat-bottomed holes;

[0164] (II) Milling: Use a milling machine to mill the two edges of the composite steel plate to achieve the target plate width, plate edge parallelism and bevel shape;

[0165] (III) Pre-bending: The composite steel plate after milling is pre-bent using a pre-bending machine to ensure that the inner diameter chord height within 150mm of the plate edge meets the corresponding pipe diameter size, so as to ensure the curvature of the pipe body.

[0166] (IV) Forming: The pre-bent composite steel plate is stamped and bent using a JCOE forming machine to form a tube with an "O" shaped opening;

[0167] (V) Pre-welding: The formed tube body is joined together and continuously welded;

[0168] (VI) Inner Welding: The inner side of the pipe body is welded using submerged arc welding (using three welding wires: the first welding wire has a welding current of 850A and a welding voltage of 32V; the second welding wire has a welding current of 600A and a welding voltage of 36V; the third welding wire has a welding current of 500A and a welding voltage of 38V; the welding speed is 1.5m / min for all three welding wires). All three welding wires are H08MnA welding wires. After welding, a weld structure dominated by pearlite is obtained, making the strength of the weld comparable to the strength of the hydrogen permeation resistant layer in the composite steel plate.

[0169] (VII) External Welding: The outer side of the pipe body is welded using submerged arc welding (using four welding wires; the welding current of the first welding wire is 1000A and the welding voltage is 32V; the welding current of the second welding wire is 850A and the welding voltage is 36V; the welding current of the third welding wire is 600A and the welding voltage is 38V; the welding current of the fourth welding wire is 500A and the welding voltage is 40V; the welding speed is 1.6m / min for all four welding wires). H08MnMoTiB welding wire is used for all four welding wires. After welding, a weld structure dominated by ferrite is obtained, so that the strength of the weld is comparable to the strength of the reinforcing layer in the composite steel plate.

[0170] (VIII) First ultrasonic test: Inspect the inner and outer welds of the pipe body and both sides of the welds;

[0171] (IX) First X-ray television inspection: The inner and outer welds of the pipe body are inspected by X-ray industrial television. A fixed X-ray equipment with single-wall single-image method (equipped with DR flat plate device) is used to conduct 100% full weld radiographic inspection of the pipe body, mainly to find volumetric defects.

[0172] (X) Mechanical expansion: The diameter of the pipe is expanded along its entire length to improve the dimensional accuracy of the pipe and improve the distribution of stress within the pipe.

[0173] (XI) Flat end: The two end faces of the pipe body are machined to ensure the sealing effect of the subsequent water pressure test;

[0174] (XII) Hydrostatic test: The mechanically enlarged pipe body is inspected using a hydrostatic testing machine to ensure that it meets the allowable pressure required by the steel grade specified in GB / T9711;

[0175] (XIII) Beveling: After the water pressure test is passed, the pipe end is processed to achieve the target pipe end bevel size;

[0176] (XIV) Second ultrasonic test: Perform ultrasonic testing on the pipe body again to check for defects that may occur after mechanical expansion and hydrostatic testing.

[0177] (XV) Second X-ray television inspection: DR digital image extraction inspection of the weld area with a length of not less than 250mm at the pipe end;

[0178] (XVI) Finished product inspection, the finished composite steel pipe is obtained (denoted as T3).

[0179] The inner diameter of T3 is 980mm; the tensile strength loss rate of T3 is 3.5%, and the yield strength is 500MPa, which can meet the requirements of high-volume, high-efficiency, long-distance, high-pressure transportation of hydrogen energy.

[0180] Example 4

[0181] Preparation of composite steel plates:

[0182] (1-1) The first steel billet (material L360, thickness 15mm) and the second steel billet (L555, thickness 80mm) are subjected to raw material pretreatment. The raw material pretreatment includes cutting the first steel billet and the second steel billet into the same size and grinding the surfaces to be composited.

[0183] (1-2) The surfaces of the first and second steel billets, after raw material pretreatment, are brought into contact to completely overlap and combine them into a weldable billet. Welding is then performed to obtain the composite billet. Multiple sheets are stacked: two sheets of each of the first and second steel billets are taken and stacked from bottom to top in the order of "second steel billet → first steel billet → first steel billet → second steel billet". During the stacking process, a high-temperature resistant insulating agent is injected between adjacent first steel billets to prevent them from rolling together later. Vacuum electron beam welding is used (welding conditions include: vacuum degree of 4.5 × 10⁻⁶). -2 Pa; welding current is 50mA, welding voltage is 50kV, welding speed is 0.6m / min), welding is performed along the contact line between the first steel billet and the second steel billet in the blank to be welded to achieve fixation;

[0184] (1-3) Heat the composite blank to 1180℃ and keep it at that temperature for 4 hours, then descale it.

[0185] (2-1) The composite billet after dephosphorization is subjected to rough rolling (starting rolling temperature is 1175-1225℃, finishing rolling temperature is 885-915℃) and finish rolling (starting rolling temperature is 825-875℃, finishing rolling temperature is 785-815℃), and the rolled plate is cooled and hot straightened to obtain the rolled part.

[0186] (2-2) The rolled part is heated to 550℃ and held for 1 hour. Then the rolled part is pre-cut and separated. The product size is initially controlled by the pre-cut and separation. Due to the presence of the release agent, when the edges of the rolled part are cut, the two sets of "first steel billet + second steel billet" naturally separate to obtain two composite steel plate pre-products. Then the composite steel plate pre-products are cold straightened and ultrasonically tested to obtain the rough product.

[0187] (2-3) The rough product is sequentially subjected to fine shearing, fine straightening and surface treatment to obtain a composite steel plate (denoted as S4);

[0188] S4 has a hydrogen permeation resistant layer and a reinforcing layer on one side of the hydrogen permeation resistant layer; wherein, the thickness of the hydrogen permeation resistant layer is 4 mm and the thickness of the reinforcing layer is 18 mm; the ratio of the yield strength of the hydrogen permeation resistant layer to the yield strength of the reinforcing layer is 1:1.53.

[0189] The tensile strength loss rate of composite steel plate S4 is 4%, and the yield strength is 550 MPa.

[0190] Composite pipes are made using S4 composite steel plates:

[0191] (I) Ultrasonic Plate Inspection: The composite steel plate S4 described above undergoes full-plate ultrasonic testing to ensure that there are no defects exceeding [a certain threshold] inside the composite steel plate. Delamination defects of equivalent size to flat-bottomed holes;

[0192] (II) Milling: Use a milling machine to mill the two edges of the composite steel plate to achieve the target plate width, plate edge parallelism and bevel shape;

[0193] (III) Pre-bending: The composite steel plate after milling is pre-bent using a pre-bending machine to ensure that the inner diameter chord height within 150mm of the plate edge meets the corresponding pipe diameter size, so as to ensure the curvature of the pipe body.

[0194] (IV) Forming: The pre-bent composite steel plate is stamped and bent using a JCOE forming machine to form a tube with an "O" shaped opening;

[0195] (V) Pre-welding: The formed tube body is joined together and continuously welded;

[0196] (VI) Inner Welding: The inner side of the pipe body is welded using submerged arc welding (using three welding wires: the first welding wire has a welding current of 850A and a welding voltage of 32V; the second welding wire has a welding current of 600A and a welding voltage of 36V; the third welding wire has a welding current of 500A and a welding voltage of 38V; the welding speed is 1.5m / min for all three welding wires). All three welding wires are H08MnA welding wires. After welding, a weld structure dominated by pearlite is obtained, making the strength of the weld comparable to the strength of the hydrogen permeation resistant layer in the composite steel plate.

[0197] (VII) External Welding: The outer side of the pipe body is welded using submerged arc welding (using four welding wires; the welding current of the first welding wire is 1000A and the welding voltage is 32V; the welding current of the second welding wire is 850A and the welding voltage is 36V; the welding current of the third welding wire is 600A and the welding voltage is 38V; the welding current of the fourth welding wire is 500A and the welding voltage is 40V; the welding speed is 1.6m / min for all four welding wires). H08MnMoTiB welding wire is used for all four welding wires. After welding, a weld structure dominated by ferrite is obtained, so that the strength of the weld is comparable to the strength of the reinforcing layer in the composite steel plate.

[0198] (VIII) First ultrasonic test: Inspect the inner and outer welds of the pipe body and both sides of the welds;

[0199] (IX) First X-ray television inspection: The inner and outer welds of the pipe body are inspected by X-ray industrial television. A fixed X-ray equipment with single-wall single-image method (equipped with DR flat plate device) is used to conduct 100% full weld radiographic inspection of the pipe body, mainly to find volumetric defects.

[0200] (X) Mechanical expansion: The diameter of the pipe is expanded along its entire length to improve the dimensional accuracy of the pipe and improve the distribution of stress within the pipe.

[0201] (XI) Flat end: The two end faces of the pipe body are machined to ensure the sealing effect of the subsequent water pressure test;

[0202] (XII) Hydrostatic test: The mechanically enlarged pipe body is inspected using a hydrostatic testing machine to ensure that it meets the allowable pressure required by the steel grade specified in GB / T9711;

[0203] (XIII) Beveling: After the water pressure test is passed, the pipe end is processed to achieve the target pipe end bevel size;

[0204] (XIV) Second ultrasonic test: Perform ultrasonic testing on the pipe body again to check for defects that may occur after mechanical expansion and hydrostatic testing.

[0205] (XV) Second X-ray television inspection: DR digital image extraction inspection of the weld area with a length of not less than 250mm at the pipe end;

[0206] (XVI) Finished product inspection, the composite steel pipe finished product is obtained (denoted as T4).

[0207] The inner diameter of T4 is 980mm; the tensile strength loss rate of T4 is 4%, and the yield strength is 550MPa, which can meet the requirements of high-volume, high-efficiency, long-distance, high-pressure transportation of hydrogen energy.

[0208] Comparative Example 1

[0209] Preparation of composite steel plates:

[0210] The composite steel plate was prepared according to the method of Example 1, the only difference being that the second steel billet in step (1-1) was made of L290 pipeline steel with a thickness of 80 mm. All other conditions and parameters were the same as in Example 1. The resulting composite steel plate (denoted as DS1) was obtained.

[0211] DS1 has a hydrogen permeation resistant layer and a reinforcing layer on one side of the hydrogen permeation resistant layer; wherein, the thickness of the hydrogen permeation resistant layer is 3 mm and the thickness of the reinforcing layer is 17.5 mm; the ratio of the yield strength of the hydrogen permeation resistant layer to the yield strength of the reinforcing layer is 1:1.

[0212] The tensile property loss rate of the composite steel plate DS1 is 3%, and the yield strength is 280 MPa.

[0213] Using composite steel plate DS1, and following the method and parameters of Example 1, a composite steel pipe was prepared to obtain the finished composite steel pipe (denoted as DT1).

[0214] The inner diameter of DT1 is 780mm; the tensile strength loss rate of DT1 is 3%, and the yield strength is 280MPa, which cannot meet the requirements for high-volume, high-efficiency, long-distance, high-pressure transportation of hydrogen energy.

[0215] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A composite steel plate, characterized in that, The composite steel plate includes a hydrogen permeation resistant layer and a reinforcing layer disposed on one side of the hydrogen permeation resistant layer; wherein the hydrogen permeation resistant layer and the reinforcing layer are made of pipeline steel, and the ratio of the yield strength of the hydrogen permeation resistant layer to the yield strength of the reinforcing layer is 1:(1.5-1.7); the preparation method of the composite steel plate includes: (1) stacking and welding a first steel billet and a second steel billet to obtain a composite billet; (2) rolling and cutting the composite billet to obtain a composite steel plate; wherein the first steel billet and the second steel billet are made of pipeline steel; the first steel billet forms the hydrogen permeation resistant layer, and the second steel billet forms the reinforcing layer; the welding is performed using vacuum electron beam welding; the conditions for vacuum electron beam welding include: vacuum degree ≤5×10 -2 Pa; welding current is 20-60mA, welding voltage is 40-60kV, and welding speed is 0.6-1.2m / min; the rolling process includes roughing and finishing; the initial rolling temperature of the roughing is 1175-1225℃, and the final rolling temperature is 885-915℃; the initial rolling temperature of the finishing is 825-875℃, and the final rolling temperature is 785-815℃.

2. The composite steel plate according to claim 1, wherein, The thickness of the hydrogen permeation resistant layer is 3-5 mm; and / or, the thickness of the reinforcing layer is 10-30 mm.

3. The composite steel plate according to claim 2, wherein, The thickness of the hydrogen permeation resistant layer is 3.5-4.5 mm; and / or, the thickness of the reinforcing layer is 16.5-17.5 mm.

4. The composite steel plate according to any one of claims 1-3, wherein, The material of the first steel billet is selected from at least one of L290 pipeline steel, L320 pipeline steel, L360 pipeline steel and L390 pipeline steel; and / or, the material of the second steel billet is selected from L485 pipeline steel and / or L555 pipeline steel.

5. A composite steel pipe, formed and welded from the composite steel plate according to any one of claims 1-4; wherein, The inner wall of the composite steel pipe is the hydrogen permeation resistant layer of the composite steel plate, and the outer wall of the composite steel pipe is the reinforcing layer of the composite steel plate.

6. The composite steel pipe according to claim 5, wherein, The inner diameter of the composite steel pipe is 400-1500mm.

7. The composite steel pipe according to claim 5 or 6, wherein, The tensile property loss rate of the composite steel pipe is <5%; and / or the yield strength of the composite steel pipe is ≥435MPa.

8. The application of the composite steel pipe according to any one of claims 5-7 in the field of hydrogen energy transportation.

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