Heterostructure hydrogen-resistant pipe as well as preparation method and application thereof
By designing a heterostructure in a steel pipe, the outside is tempered soxunite structure and the inner wall is inverted austenite structure, the hydrogen embrittlement and hydrogen permeability problems in high-pressure hydrogen environment are solved, and high strength and high hydrogen resistance are achieved. Heterostructured hydrogen-resistant pipes are suitable for high-pressure hydrogen storage tanks and hydrogen transport pipelines.
Patent Information
- Application Number
- CN202310842030.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-10
- Publication Date
- 2025-01-10
AI Technical Summary
The prior art is difficult to simultaneously improve the strength and hydrogen embrittlement resistance of metal pipes in high-pressure hydrogen environments. Especially in high-strength steels, the possibility of hydrogen embrittlement increases, and commonly used plating methods exist in high-pressure pure hydrogen environments. Hydrogen permeation problems and interface bubble damage.
Through component design and heat treatment and regulation, heterostructured steel pipes were prepared. The outside was tempered soxunite structure with high strength and the inner wall was austenite structure with strong hydrogen resistance. The specific steps include smelting, hot rolling, quenching, and cooling. Rolling, heat treatment and post-treatment to form heterostructured hydrogen-resistant pipes.
The high strength and high hydrogen resistance of the pipe in a high-pressure pure hydrogen environment are achieved, ensuring the overall performance of the pipe, especially the inverted austenite structure on the inner wall can resist hydrogen corrosion, and the external tempered sostenite structure provides high strength , improves the overall performance of the pipeline.
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Figure HDA0004331043380000011
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of pipe preparation, and in particular relates to a heterogeneous structure hydrogen-resistant pipe and a preparation method and application thereof. Background Art
[0002] Hydrogen embrittlement is the reduction in ductility of a metal material due to the absorption of hydrogen atoms. Due to the small radius of hydrogen atoms, they can easily diffuse into the metal, which subsequently reduces the stress required for crack initiation and propagation in the metal, resulting in embrittlement. Hydrogen embrittlement is a complex process involving many different micromechanisms, not all of which need to be present. These mechanisms include the formation of brittle hydrides, the creation of voids that can lead to high-pressure bubbles, enhanced internal surface decohesion, and local plasticity at the crack tip that aids crack propagation. Multiple mechanisms have been proposed and studied as the cause of embrittlement after diffuse hydrogen dissolves into the metal.
[0003] In general, the higher the strength of a steel, the higher its sensitivity to hydrogen embrittlement, meaning that the likelihood of brittle fracture in a hydrogen environment increases significantly. For example, in the case of 17-4PH precipitation hardened stainless steel, a high-strength steel, when a smooth sample was exposed to high-pressure hydrogen, its plasticity dropped from 17% to only 1.7%. As the strength of the steel increases, the fracture toughness decreases, so the likelihood of fracture due to hydrogen embrittlement increases. In high-strength steels, any material with a hardness higher than HRC32 is likely to experience early hydrogen cracking after the electroplating process, which introduces hydrogen. Lower-strength materials, such as austenitic stainless steels, have a stronger resistance to hydrogen embrittlement.
[0004] At present, the main method of preventing hydrogen embrittlement is still focused on reducing the contact between metal and hydrogen. For example, during the manufacturing and electrolysis of water, embrittlement procedures such as pickling should be avoided, as well as increased contact with elements such as sulfur and phosphates. Another method is that if the metal has not yet begun to crack, hydrogen embrittlement can be reversed by removing the hydrogen source and diffusing the hydrogen in the metal through heat treatment. This method is called low-hydrogen annealing or "baking" de-embrittlement process. For materials such as high-pressure hydrogen storage containers or hydrogen transmission pipelines that will be in a high-pressure hydrogen environment for a long time and in a hydrogen environment with high strength requirements, the methods currently used include: (1) using a coating with low hydrogen diffusivity and low hydrogen solubility. Metal coatings such as Cu, Mo, Al, Ag, Au, and W have low hydrogen diffusivity and low hydrogen solubility, and less hydrogen permeation. Under the condition of meeting the requirements of product technical conditions, a coating that does not cause hydrogen permeation can be used; (2) stress relief before plating and dehydrogenation after plating to eliminate the risk of hydrogen embrittlement. If the internal residual stress of the parts is large after quenching, welding and other processes, tempering treatment should be performed before plating to reduce the risk of serious hydrogen permeation. In principle, parts with more hydrogen infiltration during the electroplating process should be dehydrogenated as soon as possible, because the hydrogen in the coating and the surface base metal diffuses into the steel substrate, and its amount increases with time. The method of using coatings needs to consider factors such as the matching of the coating and the substrate, and the operating efficiency. In addition, in a high-pressure pure hydrogen environment, if hydrogen penetrates through the coating, the bubbles generated at the interface will cause greater damage to the substrate. Summary of the invention
[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a heterogeneous structure hydrogen-resistant pipe and its preparation method and application, and to prepare a steel pipe with different microstructures by using the method of composition design and heat treatment regulation, so that the outer part is a tempered troostite structure with high strength, and the inner wall is an austenite structure with lower strength but strong hydrogen resistance. The above-mentioned organizational design effectively improves the strength of the pipe and its hydrogen embrittlement resistance.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions:
[0007] The invention discloses a heterogeneous structure hydrogen-resistant pipe. The raw materials of the heterogeneous structure hydrogen-resistant pipe include the following components by weight percentage: Cr: 14.5wt%-15.5wt%, Ni: 7.5wt%-8.5wt%, Mn: 7.5wt%-8.5wt%, C: less than 0.05wt%, and the balance is Fe.
[0008] The present invention also discloses a method for preparing the heterogeneous structure hydrogen-resistant pipe, comprising the following steps:
[0009] S1: melting and stirring the raw materials of the heterogeneous structure hydrogen-resistant pipe at a first set temperature, then casting into a plate and hot rolling to obtain a hot-rolled plate;
[0010] S2: heating the hot-rolled plate at a second set temperature for a first set time, then quenching and cold rolling to a target thickness to obtain a plate with a martensitic structure;
[0011] S3: heat treating one side of the plate having the martensitic structure to obtain a heterogeneous structure plate;
[0012] S4: After heating the heterogeneous structure plate to a third set temperature, hot-rolling the plate and keeping the temperature for a second set time allows the martensite structure of the heterogeneous structure plate to undergo a phase transformation into a tempered bainite structure, followed by post-processing to obtain a heterogeneous structure hydrogen-resistant pipe.
[0013] In a specific implementation process, in S1, the first set temperature is 1500-1550° C., and the pressing amount of the hot rolling is greater than 30%.
[0014] In a specific implementation process, in S2, the second set temperature is 1100-1200°C, the first set time is 1-2h, and the cold rolling pressing amount is greater than 30%.
[0015] In the specific implementation process, in S3, the heating temperature of the heat treatment is 900-950° C., and the heating time of the heat treatment is set based on the tube wall thickness. The relationship between the heating time of the heat treatment and the heating temperature of the heat treatment and the tube wall thickness is as follows:
[0016] t=(1000-T) / 10-d, where t is the heating time in min, T is the heating temperature in °C, and d is the tube wall thickness in mm.
[0017] In the specific implementation process, in S3, the structure of one side of the heterogeneous structure plate after heat treatment is an inverted austenite structure, and the other side is a martensite structure.
[0018] In a specific implementation process, in S4, the third set temperature is 300-500° C., and the second set time is 30-60 minutes.
[0019] In the specific implementation process, in S4, the post-processing includes rolling, butting, welding, rounding, circumferential butt jointing, and flaw detection inspection in sequence.
[0020] The present invention also provides an application of the heterogeneous structure hydrogen-resistant pipe in high-pressure hydrogen storage tank transfer pipes and hydrogen transmission pipelines.
[0021] Compared with the prior art, the present invention has the following beneficial effects:
[0022] The present invention provides a heterogeneous structure hydrogen-resistant pipe material, which uses hydrogen-resistant raw materials to achieve the effect of hydrogen resistance. The raw materials have high strength by adding a large amount of alloy elements for solid solution strengthening and improving the hardenability of the material. By changing the hydrogen resistance of the base material, it still has strong hydrogen resistance in a high-pressure pure hydrogen environment. At the same time, the C content is strictly controlled to make it have good weldability, and a straight seam pipe can be prepared by welding.
[0023] The present invention provides a method for preparing a heterogeneous structure hydrogen-resistant pipe. The heterogeneous structure is obtained by partial heating, that is, only one side of the plate is heated, so that one side is an inverted austenite structure, and the rest is a martensite structure. Then, post-treatment is performed at a set heating temperature, so that the high-strength plate can be rounded and the martensite undergoes a phase change to become tempered bainite, while the inverted austenite does not change at this temperature, thereby obtaining a heterogeneous structure pipe. The inner wall of the heterogeneous structure pipe is an inverted austenite structure, which has low strength and excellent hydrogen embrittlement resistance. As the inner wall of the inner channel of the pipeline, it can resist hydrogen corrosion. The rest of the pipeline is a tempered bainite structure with high strength, thereby improving the overall strength of the pipeline, and enabling the pipeline to have both high strength and high hydrogen resistance. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 It is a tensile performance curve diagram before and after hydrogen charging of the present invention. DETAILED DESCRIPTION
[0025] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.
[0026] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.
[0027] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values within the range (including integers and fractions).
[0028] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”
[0029] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.
[0030] The invention provides a heterogeneous structure hydrogen-resistant pipe and a preparation method and application thereof.
[0031] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.
[0032] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.
[0033] The present invention provides a heterogeneous structure hydrogen-resistant pipe, wherein the raw materials of the pipe include Cr, Ni, Mn, C and Fe by weight percentage;
[0034] The Cr content is 14.5wt% to 15.5wt%, the Ni content is 7.5wt% to 8.5wt%, the Mn content is 7.5wt% to 8.5wt%, the C content is less than 0.05wt%, and Fe is the balance. The characteristic of this composition design is to add a large amount of alloy elements, the purpose is to strengthen the material through solid solution and improve the hardenability to make it have high strength, and at the same time strictly control the C content to make it have good weldability, the purpose is to prepare straight seam pipes by welding.
[0035] The present invention also provides a method for preparing the above-mentioned heterogeneous structure hydrogen-resistant pipe, and the specific steps are as follows:
[0036] (1) The material of the above alloy composition is used to prepare a plate by melting, hot rolling and cold rolling.
[0037] First, the above materials are mixed according to the above weight percentages, then melted and stirred at 1500-1550°C, then cast into plates and hot-rolled, and the hot-rolling pressure should be greater than 30% to eliminate the pores. The hot-rolled plates are reheated to 1100-1200°C and kept warm for 1-2 hours, and then quenched in water. The quenched plates are cold-rolled, and the cold-rolling pressure should be greater than 30% to the target thickness, at which time the entire plate is a martensitic structure.
[0038] (2) Heat treatment is performed on either side of the plate. The heat treatment method is to use a continuous flame spray gun to heat one side of the plate. The heat-treated side serves as the inner wall of the steel pipe. The structure of the heated side is reversed austenite, while the unheated side is still martensite. The heating surface temperature is 900-950°C. The specific heating time depends on the thickness of the tube wall. The relationship between the heating temperature, time and tube wall is as follows:
[0039] t = (1000-T) / 10-d, where t is the heating time in min, T is the heating temperature in °C, and d is the wall thickness in mm (this patent is limited to the production of pipes with a wall thickness of less than 8 mm).
[0040] At this time, the plate is a heterogeneous structure plate with martensite on the outside and reverse austenite on the inside. The heterogeneous structure plate is then hot rolled.
[0041] (3) Since martensite has high strength and poor plasticity, it needs to be heated when rolling the pipe, and the heating temperature is 300-500℃. At high temperature, martensite not only becomes more plastic, so it can be completely rolled, but also undergoes a phase transformation from martensite to tempered troostite at this temperature, which improves its plasticity. The reversed austenite on the inside is not affected by this temperature, and the organizational structure does not change. When heating, the plate needs to be kept warm for 30-60 minutes to make it undergo a phase transformation, and then it is rolled, butted, welded, rounded, butted, butted, and flaw detection is performed to complete the preparation of the straight seam pipe and obtain a heterogeneous structure hydrogen-resistant pipe.
[0042] The heterogeneous structure plate is rolled at a heating temperature. The heating temperature is set so that the high-strength plate can be rolled and the martensite undergoes a phase transformation to tempered troostite, while the reversed austenite does not change at this temperature, so that a heterogeneous structure pipe can be obtained. The outer side of the heterogeneous structure hydrogen-resistant pipe is tempered troostite structure, and the inner side is reversed austenite structure, which has high strength and high hydrogen resistance.
[0043] In order to successfully realize the above-mentioned heterogeneous structure pipe with high strength and high hydrogen resistance, (1) the plate composition must be strictly configured according to the component ratio, otherwise it will affect quenching or welding; (2) the pressing amount during hot rolling should be higher than 30%, otherwise the porosity in the plate will exceed the standard; (3) after hot rolling, the plate needs to be heated again and kept warm before quenching to make the plate become martensite. Since the alloy component in the raw material has greatly improved the hardenability of the material, there is no need to stipulate the quenching medium; (4) the pressing amount during cold rolling should be higher than 30% to break the grains; (5) the heat treatment in the tempering step is performed according to the above formula to ensure the appropriate volume fraction of reversed austenite and its distribution only on one side of the plate; (6) the set temperature is used for heating in the rounding step to ensure that the rounding is successful and the reversed austenite structure is not affected.
[0044] Embodiment 1:
[0045] The following ingredients are used as the pipe ingredients. Cr content is: 14.7wt%, Ni content is: 7.5wt%, Mn content is: 8wt%, C content is 0.02wt%, Fe is the balance, totaling 300kg. First, use a vacuum furnace to melt all the ingredients, use a magnesia crucible, melt the ingredients and cast them into plates. The thickness of the plate is 20mm. First, the plate is heated and hot-rolled. The single pass of hot rolling has a pressure of 1mm. 10 passes of hot rolling are repeated. The thickness of the plate after hot rolling is 12mm, and then it is kept at 1200℃ for 1h and quenched. The quenched sample is cold rolled and rolled to 8mm in 10 passes. Then use a flame spray gun to heat one side of the plate at 900℃ for 50 minutes. The heated plate is subjected to butt-welding-rounding-circumferential butt-jointing-flaw detection at 300℃.
[0046] Embodiment 2:
[0047] The following ingredients are used as the pipe ingredients. Cr content is: 15wt%, Ni content is: 8.5wt%, Mn content is: 7.8wt%, C content is 0.02wt%, Fe is the balance, totaling 300kg. First, use a vacuum furnace to melt all the ingredients, use a magnesia crucible, melt the ingredients and cast them into plates. The thickness of the plate is 20mm. First, the plate is heated and hot-rolled. The single pass of hot rolling has a pressure of 1.5mm. 10 passes of hot rolling are repeated. The thickness of the plate after hot rolling is 10mm, and then it is kept at 1200℃ for 1h and quenched. The quenched sample is cold rolled and rolled to 6mm in 15 passes. Then use a flame spray gun to heat one side of the plate at 900℃ for 25 minutes. The heated plate is subjected to butt-welding-rounding-circumferential butt-jointing-flaw detection at 330℃.
[0048] Embodiment 3:
[0049] The following ingredients are used as the pipe ingredients. Cr content is: 15.5wt%, Ni content is: 8.5wt%, Mn content is: 7.7wt%, C content is 0.01wt%, Fe is the balance, totaling 300kg. First, use a vacuum furnace to melt all the ingredients, use a magnesia crucible, and cast the ingredients into plates after melting. The thickness of the plate is 20mm. First, the plate is heated and hot-rolled. The single pass of hot rolling has a pressure of 1.2mm. 10 passes of hot rolling are repeated. The thickness of the plate after hot rolling is 11mm, and then it is kept at 1200℃ for 1h and quenched. The quenched sample is cold rolled and rolled to 6mm in 20 passes. Then use a flame spray gun to heat one side of the plate at 900℃ for 25 minutes. The heated plate is subjected to butt-welding-rounding-circumferential butt-jointing-flaw detection at 350℃.
[0050] Embodiment 4:
[0051] The following ingredients are used as the pipe ingredients for batching. Cr content is: 14.5wt%, Ni content is: 8.5wt%, Mn content is: 7.5wt%, C content is 0.05wt%, Fe is the balance, totaling 300kg. First, use a vacuum furnace to melt all the ingredients, use a magnesia crucible, melt the ingredients and cast them into plates. The thickness of the plate is 20mm. First, the plate is heated and hot-rolled. The single pass of hot rolling has a pressure of 1.2mm. 10 passes of hot rolling are repeated. The thickness of the plate after hot rolling is 11mm, and then it is kept at 1100℃ for 2h and quenched. The quenched sample is cold rolled and rolled to 6mm in 20 passes. Then use a flame spray gun to heat one side of the plate at 950℃ for 25 minutes. The heated plate is subjected to butt-welding-rounding-circumferential butt-jointing-flaw detection at 400℃.
[0052] Embodiment 5:
[0053] The following ingredients are used as the pipe ingredients for batching. Cr content is: 15.5wt%, Ni content is: 8.5wt%, Mn content is: 8.5wt%, C content is 0.04wt%, Fe is the balance, totaling 300kg. First, use a vacuum furnace to melt all the ingredients, use a magnesia crucible, melt the ingredients and cast them into plates. The thickness of the plate is 20mm. First, the plate is heated and hot-rolled. The single pass of hot rolling has a pressure of 1.2mm. 10 passes of hot rolling are repeated. The thickness of the plate after hot rolling is 11mm, and then it is kept at 1150℃ for 1.5h and quenched. The quenched sample is cold rolled and rolled to 6mm in 20 passes. Then use a flame spray gun to heat one side of the plate at 950℃ for 25 minutes. The heated plate is subjected to butt-welding-rounding-circumferential butt-jointing-flaw detection at 500℃.
[0054] Depend on Figure 1As shown, the material of the present invention is 50mA / cm 2 After being charged with hydrogen for 12 hours at a current density of , the plasticity is about 40% before hydrogen charging and 22% after hydrogen charging, which still maintains a certain plasticity and has work hardening. The material still maintains a high plasticity in a high hydrogen environment.
[0055] The present invention uses steel with specific components and a specific pipe preparation process to prepare the above-mentioned pipe with both high strength and high hydrogen resistance, which can be used for high-pressure hydrogen storage tank transfer pipes, hydrogen transmission pipelines or hydrogen environments in the refining industry. The inner wall of the straight seam pipe is a reverse austenite structure, which has low strength but excellent resistance to hydrogen embrittlement. As the inner wall of the pipeline, it can resist hydrogen corrosion. The rest of the pipeline is a tempered bainite structure with high strength, thereby improving the overall strength of the pipeline. The pipeline has both high strength and high hydrogen resistance.
[0056] The above contents are only for explaining the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.
Claims
1. A heterogeneous structure hydrogen-resistant pipe, characterized in that: Calculated by weight percentage, the raw materials of the heterogeneous structure hydrogen-resistant pipe include the following components: Cr: 14.5wt% to 15.5wt%, Ni: 7.5wt% to 8.5wt%, Mn: 7.5wt% to 8.5wt%, C: less than 0.05wt%, and the balance is Fe.
2. The method for preparing a heterogeneous structure hydrogen-resistant pipe according to claim 1, characterized in that: The following steps are involved: S1: melting and stirring the raw materials of the heterogeneous structure hydrogen-resistant pipe at a first set temperature, then casting into a plate and hot rolling to obtain a hot-rolled plate; S2: heating the hot-rolled plate at a second set temperature for a first set time, then quenching and cold rolling to a target thickness to obtain a plate with a martensitic structure; S3: heat treating one side of the plate having the martensitic structure to obtain a heterogeneous structure plate; S4: After heating the heterogeneous structure plate to a third set temperature, hot-rolling the plate and keeping the temperature for a second set time allows the martensite structure of the heterogeneous structure plate to undergo a phase transformation into a tempered bainite structure, followed by post-processing to obtain a heterogeneous structure hydrogen-resistant pipe.
3. The method for preparing a heterogeneous structure hydrogen-resistant pipe according to claim 2, characterized in that: In S1, the first set temperature is 1500-1550° C., and the reduction amount of the hot rolling is greater than 30%.
4. The method for preparing a heterogeneous structure hydrogen-resistant pipe according to claim 2, characterized in that: In S2, the second set temperature is 1100-1200°C, the first set time is 1-2 hours, and the cold rolling pressing amount is greater than 30%.
5. The method for preparing a heterogeneous structure hydrogen-resistant pipe according to claim 2, characterized in that: In S3, the heating temperature of the heat treatment is 900-950° C., and the heating time of the heat treatment is set based on the tube wall thickness. The relationship between the heating time of the heat treatment, the heating temperature of the heat treatment, and the tube wall thickness is as follows: t = (1000-T) / 10-d, where t is the heating time, T is the heating temperature, and d is the tube wall thickness.
6. The method for preparing a heterogeneous structure hydrogen-resistant pipe according to claim 2, characterized in that: In S3, the microstructure of one side of the heat-treated heterogeneous structure plate is an inverted austenite microstructure, and the other side is a martensite microstructure.
7. The method for preparing a heterogeneous structure hydrogen-resistant pipe according to claim 2, characterized in that: In S4, the third set temperature is 300-500° C., and the second set time is 30-60 minutes.
8. The method for preparing a heterogeneous structure hydrogen-resistant pipe according to claim 2, characterized in that: In S4, the post-processing includes rolling, butting, welding, rounding, circumferential butt jointing, and flaw detection.
9. An application of the heterogeneous structure hydrogen-resistant pipe according to claim 1 in high-pressure hydrogen storage tank transfer pipes and hydrogen transmission pipelines.