Anti-hydrogen embrittlement stainless steel, and preparation method and application thereof

Abstract

The application provides an anti-hydrogen embrittlement stainless steel and a preparation method and application thereof, and relates to the technical field of special stainless steel.The anti-hydrogen embrittlement stainless steel provided by the application contains the following elements in percentage by mass: 0.05-0.08% of C, 7-9% of Mn, 13-16% of Cr, 8-10% of Ni, 0.8-1% of Cu, 2-3% of Co, 0.2-0.4% of N, 1-2% of RE, 0.01-0.05% of impurities and the balance of Fe; the RE contains at least one of La, Ce and Y. The multiple metal elements and non-metal elements are used to cooperate and jointly act, the Mn and N can stabilize the austenite structure, can improve the structural strength and toughness of the anti-hydrogen embrittlement stainless steel, and can make the stainless steel have the anti-hydrogen embrittlement capability, and the anti-delayed fracture performance is improved.

Description

Technical Field

[0001] This invention relates to the field of special stainless steel technology, and in particular to a hydrogen embrittlement resistant stainless steel, its preparation method and application. Background Technology

[0002] The transportation and storage of hydrogen energy are essential components of the hydrogen economy and industrial chain. Since chemical hydrogen storage technology is still immature, hydrogen-powered vehicles and related facilities currently rely primarily on physical hydrogen storage in the form of high-pressure hydrogen gas. For example, the hydrogen cylinders mounted on the roof of hydrogen-powered buses have key components such as the inner liner, transmission pipes, valves, and pressure regulators made of metal materials. However, to ensure long-term, stable, and reliable operation under hydrogen conditions, the hydrogen embrittlement problem of these metal materials must be considered.

[0003] When hydrogen atoms enter the cavities of the metal lattice or the interstices between metal atoms from the metal surface, forming substitutional or interstitial solid solutions, they diffuse within these interstices due to the concentration gradient, increasing the hydrogen concentration in the metal matrix. When defects exist in the metal, the dissolved hydrogen will precipitate at the defects through diffusion and desorption processes, combining to form hydrogen molecules, thus causing hydrogen embrittlement. Hydrogen embrittlement in metallic materials manifests as reduced strength and toughness, decreased fatigue life, and sudden intergranular fracture, making it difficult to maintain good mechanical properties over extended periods. Therefore, a solution is urgently needed to address these problems. Summary of the Invention

[0004] The purpose of this invention is to provide a hydrogen embrittlement resistant stainless steel, its preparation method and application, which can improve the resistance to hydrogen embrittlement while improving the structural strength.

[0005] In a first aspect, the present invention provides a hydrogen-embrittlement-resistant stainless steel comprising, by mass percentage: 0.05-0.08% C, 7-9% Mn, 13-16% Cr, 8-10% Ni, 0.8-1% Cu, 2-3% Co, 0.2-0.4% N, 1-2% RE, 0.01-0.05% impurities, and the balance Fe; wherein the RE comprises at least one of La, Ce, and Y.

[0006] The hydrogen embrittlement-resistant stainless steel provided by this invention utilizes a combination of various metallic and non-metallic elements. Mn and N stabilize the austenitic structure, improving the structural strength and toughness of the hydrogen embrittlement-resistant stainless steel. This also enhances its resistance to hydrogen embrittlement and improves its resistance to delayed fracture. Furthermore, it prevents hydrogen embrittlement caused by localized negative hydrogen atoms resulting from deformation twin formation. Simultaneously, the addition of RE effectively reduces the wetting angle and promotes heterogeneous nucleation, thereby refining the grain size, reducing traps in the stainless steel, and altering the morphology of the Fe phase. These factors synergistically change the grain morphology and hydrogen embrittlement resistance of the stainless steel.

[0007] Optionally, when the RE is a mixture of La and Ce, the hydrogen embrittlement resistant stainless steel comprises, by mass percentage: 0.06-0.07% C, 8-9% Mn, 14-15% Cr, 8-9% Ni, 0.9-1% Cu, 2.3-2.5% Co, 0.3-0.4% N, 0.6-0.8% La, 0.5-0.6% Ce, 0.01-0.05% impurities, and the balance Fe.

[0008] Optionally, when the RE is a mixture of La, Ce and Y, the hydrogen embrittlement resistant stainless steel comprises, by mass percentage: 0.05-0.06% C, 7.5-8.5% Mn, 13.5-15.5% Cr, 8.4-9.7% Ni, 0.8-0.9% Cu, 2-2.5% Co, 0.25-0.3% N, 0.3-0.5% La, 0.5-0.7% Ce, 0.4-0.5% Y, 0.01-0.05% impurities and the balance Fe.

[0009] Secondly, the present invention also provides a method for preparing any of the above-mentioned optional hydrogen embrittlement-resistant stainless steels, comprising the following steps:

[0010] The pure Fe, Fe-C master alloy, Fe-Mn master alloy, Fe-Cr master alloy, Fe-Ni master alloy, Fe-Cu master alloy, Fe-Re master alloy, Fe-Co master alloy, and Fe-N master alloy are smelted using steelmaking processes and then refined by LF+RH to obtain alloy melts; the RE in the Fe-Re master alloy includes at least one of La, Ce, and Y;

[0011] After the alloy melt is cast into shape, it is subjected to annealing, normalizing, quenching, tempering and solution treatment in sequence to obtain the alloy material. The alloy material is placed at 1250-1300℃ for 48-55h and then oil-cooled to room temperature to obtain hydrogen embrittlement resistant stainless steel.

[0012] The preparation method provided by this invention, after smelting and refining various metallic and non-metallic elements, enables the uniform distribution of various components. After casting the alloy melt, multiple heat treatments can improve the mechanical properties and resistance to hydrogen embrittlement. In particular, through solution treatment and subsequent heat treatment at 1250-1300℃, the σ-phase ferrite in the stainless steel can be dissolved to the maximum extent, thereby reducing the channels for rapid hydrogen diffusion and thus improving the resistance to hydrogen embrittlement of the stainless steel.

[0013] Optionally, the process of obtaining an alloy melt through LF+RH refining includes: obtaining a mixed melt after LF+RH refining, measuring and adjusting the content of each element in the mixed melt, and then obtaining an alloy melt.

[0014] Optionally, the annealing process after casting the alloy melt includes: casting the alloy melt to obtain an alloy billet; holding the alloy billet at a vacuum state of 800-900℃ or an inert atmosphere of 850-900℃ for 4-5 hours and then cooling it to room temperature in the furnace to obtain the annealed alloy material.

[0015] Optionally, the normalizing process includes: uniformly heating the annealed alloy material to 950-1000℃ under vacuum or inert atmosphere and holding it at that temperature for 3-5 hours, then cooling it to room temperature in the furnace to obtain the normalized alloy material; wherein, during the uniform heating of the annealed alloy material, the heating rate is 8-10℃ / min.

[0016] Optionally, the quenching process includes: uniformly heating the normalized alloy material to 900-950℃ and holding it at that temperature for 6-8 hours in a vacuum environment or inert atmosphere, then cooling it to 250-300℃ in the furnace, and finally water-cooling or oil-cooling it to room temperature to obtain the quenched alloy material; wherein, during the uniform heating of the normalized alloy material, the heating rate is 8-10℃ / min.

[0017] Optionally, the tempering process includes: uniformly heating the quenched alloy material to 600-650℃ and holding it at that temperature for 3-5 hours in a vacuum environment or an inert atmosphere, and then cooling it to room temperature in the furnace to obtain the tempered alloy material; wherein, during the uniform heating of the quenched alloy material, the heating rate is 8-10℃ / min.

[0018] Optionally, the solution treatment includes: transferring the tempered alloy material from room temperature to a vacuum environment of 800-850°C within 3-5 seconds, holding it at that temperature for 2-3 hours, and then oil-cooling it to room temperature to obtain the precursor material; and transferring the precursor material from room temperature to a vacuum environment of 450-500°C within 3-5 seconds, holding it at that temperature for 3-5 hours, and then cooling it to room temperature in the furnace to obtain the alloy material.

[0019] Thirdly, the present invention also provides the application of any of the above-mentioned optional hydrogen embrittlement-resistant stainless steels, or the hydrogen embrittlement-resistant stainless steels prepared by any of the above-mentioned optional preparation methods, in molding for use in hydrogen energy transportation equipment, wherein the hydrogen energy transportation equipment includes at least one of storage tanks and transportation pipelines. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0021] This invention provides a hydrogen embrittlement-resistant stainless steel, comprising the following elements by mass percentage: 0.05-0.08% C, 7-9% Mn, 13-16% Cr, 8-10% Ni, 0.8-1% Cu, 2-3% Co, 0.2-0.4% N, 1-2% RE, 0.01-0.05% impurities, and the balance Fe; wherein RE includes at least one of La, Ce, and Y. In practice, during the synthesis of hydrogen embrittlement-resistant stainless steel, the loss of elements due to ignition during smelting and processing must be considered when weighing the raw materials.

[0022] In some embodiments, when RE is a mixture of La and Ce, the hydrogen embrittlement resistant stainless steel comprises, by mass percentage: 0.06-0.07% C, 8-9% Mn, 14-15% Cr, 8-9% Ni, 0.9-1% Cu, 2.3-2.5% Co, 0.3-0.4% N, 0.6-0.8% La, 0.5-0.6% Ce, 0.01-0.05% impurities, and the balance Fe.

[0023] In some embodiments, when RE is a mixture of La, Ce and Y, the hydrogen embrittlement resistant stainless steel comprises, by mass percentage: 0.05-0.06% C, 7.5-8.5% Mn, 13.5-15.5% Cr, 8.4-9.7% Ni, 0.8-0.9% Cu, 2-2.5% Co, 0.25-0.3% N, 0.3-0.5% La, 0.5-0.7% Ce, 0.4-0.5% Y, 0.01-0.05% impurities and the balance Fe.

[0024] This invention also provides a method for preparing hydrogen embrittlement-resistant stainless steel, comprising the following steps:

[0025] S1. Pure Fe, Fe-C master alloy, Fe-Mn master alloy, Fe-Cr master alloy, Fe-Ni master alloy, Fe-Cu master alloy, Fe-Re master alloy, Fe-Co master alloy, and Fe-N master alloy are smelted using steelmaking processes and then refined by LF+RH to obtain an alloy melt; wherein RE in the Fe-Re master alloy includes at least one of La, Ce, and Y;

[0026] S2. After casting the alloy melt into shape, it is subjected to annealing, normalizing, quenching, tempering and solution treatment in sequence to obtain the alloy material. The alloy material is placed at 1250-1300℃ for 48-55h and then oil-cooled to room temperature to obtain hydrogen embrittlement resistant stainless steel.

[0027] In some embodiments, when performing step S1 to smelt multiple intermediate alloys using steelmaking processes, the stainless steel smelting process commonly used in the art can be specifically adopted, in which multiple raw materials are mixed and put into a vacuum smelting furnace for high-temperature melting and smelting.

[0028] In some embodiments, when performing step S1, the selected Fe-C master alloy, Fe-Mn master alloy, Fe-Cr master alloy, Fe-Ni master alloy, Fe-Cu master alloy, Fe-Re master alloy, Fe-Co master alloy, and Fe-N master alloy can all be commercially available products. At the same time, during smelting, conventional grinding methods can be used to remove the oxide scale on the surface of the raw materials.

[0029] Specifically, Fe-Re master alloys can be replaced by a combination of at least one of Fe-La master alloys, Fe-Ce master alloys, and Fe-Y master alloys. For example, when stainless steel contains La and Ce elements, Fe-La master alloys and Fe-Ce master alloys can be used to replace Fe-Re master alloys.

[0030] In some embodiments, during step S1, when performing LF+RH refining to obtain the alloy melt, a refining process commonly used in the art can be adopted, which has no significant impact on the mechanical properties and hydrogen embrittlement resistance of the final hydrogen-resistant stainless steel product.

[0031] In some embodiments, the process of performing step S1, which involves LF+RH refining to obtain an alloy melt, includes: performing LF+RH refining to obtain a mixed melt, measuring and adjusting the content of each element in the mixed melt, and then obtaining an alloy melt.

[0032] In some embodiments, during step S2, which involves casting the alloy melt and then annealing it, the process includes casting the alloy melt to obtain an alloy billet; holding the alloy billet at a vacuum of 800-900°C or an inert atmosphere of 850-900°C for 4-5 hours and then cooling it in the furnace to room temperature to obtain the annealed alloy material.

[0033] In some embodiments, when performing step S2, the normalizing process includes: uniformly heating the annealed alloy material to 950-1000°C under vacuum or inert atmosphere and holding it at that temperature for 3-5 hours, then cooling it to room temperature in the furnace to obtain the normalized alloy material; wherein, during the process of uniformly heating the annealed alloy material, the heating rate is 8-10°C / min.

[0034] In some embodiments, when performing step S2, the quenching process includes: uniformly heating the normalized alloy material to 900-950°C and holding it at that temperature for 6-8 hours in a vacuum environment or inert atmosphere, then cooling it to 250-300°C in the furnace, and finally water-cooling or oil-cooling it to room temperature to obtain the quenched alloy material; wherein, during the process of uniformly heating the normalized alloy material, the heating rate is 8-10°C / min.

[0035] In some embodiments, when performing step S2, tempering, the process includes: uniformly heating the quenched alloy material to 600-650°C and holding it at that temperature for 3-5 hours in a vacuum environment or an inert atmosphere, and then cooling it to room temperature in the furnace to obtain a tempered alloy material; wherein, during the process of uniformly heating the quenched alloy material, the heating rate is 8-10°C / min.

[0036] In some embodiments, when performing step S2, the solution treatment includes: transferring the tempered alloy material from room temperature to a vacuum environment of 800-850°C within 3-5 seconds, holding it at that temperature for 2-3 hours, and then oil-cooling it to room temperature to obtain the precursor material; transferring the precursor material from room temperature to a vacuum environment of 450-500°C within 3-5 seconds, holding it at that temperature for 3-5 hours, and then cooling it to room temperature in the furnace to obtain the alloy material.

[0037] In fact, the present invention also provides a hydrogen embrittlement resistant stainless steel according to any of the above embodiments, or a hydrogen embrittlement resistant stainless steel prepared by the preparation method in any of the above embodiments, for use in forming hydrogen energy transportation equipment, wherein the hydrogen energy transportation equipment includes at least one of a storage tank and a transportation pipeline.

[0038] Example 1

[0039] This embodiment 1 provides a method for preparing a hydrogen embrittlement resistant stainless steel containing La and Ce, including the following steps:

[0040] S1. Based on the preset contents of 0.06% C, 9% Mn, 14% Cr, 9% Ni, 0.9% Cu, 2.3% Co, 0.3% N, 0.8% La, 0.6% Ce, and the balance Fe, weigh pure Fe, Fe-C master alloy, Fe-Mn master alloy, Fe-Cr master alloy, Fe-Ni master alloy, Fe-Cu master alloy, Fe-La master alloy, Fe-Ce master alloy, Fe-Co master alloy, and Fe-N master alloy. After removing the surface oxide scale by polishing with 200-grit sandpaper, preheat the mixture and then put the raw materials into a vacuum smelting furnace for conventional steelmaking processes. After smelting, LF-RH refining is performed to obtain the melt to be tested. The content of each element in the melt to be tested is measured using a content analysis device. After adjusting the content deviation of the melt to be tested to be less than 10% from the preset content, the alloy melt is obtained.

[0041] S2. After casting the alloy melt into an alloy billet, the alloy billet is held in a vacuum environment at 850°C for 5 hours and then cooled to room temperature in the furnace to obtain an annealed alloy material. The annealed alloy material is then heated to 980°C from room temperature at a rate of 10°C / min in a vacuum environment and held for 5 hours, and then cooled to room temperature in the furnace to obtain a normalized alloy material. In a vacuum environment, the normalized alloy material is heated to 930°C from room temperature at a rate of 10°C / min and held for 8 hours, and then cooled to 270°C in the furnace. It is then quickly removed and oil-cooled to room temperature to obtain a quenched alloy material. In a vacuum environment, a quenched alloy material is heated from room temperature to 630°C at a rate of 10°C / min and held for 5 hours before being cooled to room temperature in the furnace to obtain a tempered alloy material. The tempered alloy material is then transferred from room temperature to a vacuum environment at 820°C within 3 seconds and held for 2 hours before being oil-cooled to room temperature to obtain a precursor material. The precursor material is then transferred from room temperature to a vacuum environment at 470°C within 3 seconds and held for 3 hours before being cooled to room temperature in the furnace to obtain an alloy material. The alloy material is then transferred to a vacuum environment at 1260°C and held for 50 hours before being oil-cooled to room temperature to obtain a hydrogen-resistant stainless steel.

[0042] Example 2

[0043] This embodiment 2 provides a method for preparing a hydrogen embrittlement resistant stainless steel containing La, Ce, and Y, including the following steps:

[0044] S1. Based on the preset contents of 0.06% C, 8.2% Mn, 14.5% Cr, 9.1% Ni, 0.84% ​​Cu, 2.3% Co, 0.27% N, 0.4% La, 0.56% Ce, 0.43% Y, and the balance Fe, weigh pure Fe, Fe-C master alloy, Fe-Mn master alloy, Fe-Cr master alloy, Fe-Ni master alloy, Fe-Cu master alloy, Fe-La master alloy, Fe-Ce master alloy, Fe-Y master alloy, Fe-Co master alloy, and Fe-N master alloy. After removing the surface oxide scale by polishing with 200-grit sandpaper and preheating, put the raw materials into a vacuum smelting furnace for conventional steelmaking process smelting, and then perform LF-RH refining to obtain the melt to be tested. Use content analysis equipment to measure the content of each element in the melt to be tested, and adjust the content deviation of the melt to be tested to be less than 10% of the preset content to obtain the alloy melt.

[0045] S2. After casting the alloy melt into an alloy billet, the alloy billet is held in a vacuum environment at 870℃ for 4 hours and then cooled to room temperature in the furnace to obtain an annealed alloy material. The annealed alloy material is then heated to 1000℃ from room temperature at a rate of 8℃ / min in a vacuum environment and held for 3 hours, and then cooled to room temperature in the furnace to obtain a normalized alloy material. In a vacuum environment, the normalized alloy material is heated to 950℃ from room temperature at a rate of 8℃ / min and held for 6 hours, and then cooled to 250℃ in the furnace. It is then quickly removed and oil-cooled to room temperature to obtain a quenched alloy material. In a vacuum environment, a quenched alloy material is heated from room temperature to 650°C at a rate of 8°C / min and held for 3 hours before being cooled to room temperature in the furnace to obtain a tempered alloy material. The tempered alloy material is then transferred from room temperature to a vacuum environment at 850°C within 3 seconds and held for 3 hours before being oil-cooled to room temperature to obtain a precursor material. The precursor material is then transferred from room temperature to a vacuum environment at 500°C within 3 seconds and held for 5 hours before being cooled to room temperature in the furnace to obtain an alloy material. The alloy material is then transferred to a vacuum environment at 1290°C and held for 52 hours before being oil-cooled to room temperature to obtain a hydrogen-resistant stainless steel.

[0046] Example 3

[0047] This embodiment 3 provides a method for preparing a La-containing hydrogen embrittlement-resistant stainless steel, comprising the following steps:

[0048] S1. Based on the preset contents of 0.06% C, 8.2% Mn, 14.5% Cr, 9.1% Ni, 0.84% ​​Cu, 2.3% Co, 0.27% N, 1.5% La, and the balance Fe, weigh pure Fe, Fe-C master alloy, Fe-Mn master alloy, Fe-Cr master alloy, Fe-Ni master alloy, Fe-Cu master alloy, Fe-La master alloy, Fe-Co master alloy, and Fe-N master alloy. After removing the surface oxide scale by polishing with 200-grit sandpaper, preheat the mixture and then put the raw materials into a vacuum smelting furnace for conventional steelmaking processes. After smelting, LF-RH refining is performed to obtain the melt to be tested. The content of each element in the melt to be tested is measured using a content analysis device, and the content deviation of the melt to be tested is adjusted to be less than 10% from the preset content to obtain the alloy melt.

[0049] S2. After casting the alloy melt into an alloy billet, the alloy billet is held in a vacuum environment at 870℃ for 4 hours and then cooled to room temperature in the furnace to obtain an annealed alloy material. The annealed alloy material is then heated to 1000℃ from room temperature at a rate of 8℃ / min in a vacuum environment and held for 3 hours, and then cooled to room temperature in the furnace to obtain a normalized alloy material. In a vacuum environment, the normalized alloy material is heated to 950℃ from room temperature at a rate of 8℃ / min and held for 6 hours, and then cooled to 250℃ in the furnace. It is then quickly removed and oil-cooled to room temperature to obtain a quenched alloy material. In a vacuum environment, a quenched alloy material is heated from room temperature to 650°C at a rate of 8°C / min and held for 3 hours before being cooled to room temperature in the furnace to obtain a tempered alloy material. The tempered alloy material is then transferred from room temperature to a vacuum environment at 850°C within 3 seconds and held for 3 hours before being oil-cooled to room temperature to obtain a precursor material. The precursor material is then transferred from room temperature to a vacuum environment at 500°C within 3 seconds and held for 5 hours before being cooled to room temperature in the furnace to obtain an alloy material. The alloy material is then transferred to a vacuum environment at 1290°C and held for 52 hours before being oil-cooled to room temperature to obtain a hydrogen-resistant stainless steel.

[0050] Example 4

[0051] This embodiment 4 provides a method for preparing Ce-containing hydrogen embrittlement resistant stainless steel, including the following steps:

[0052] S1. Based on the preset contents of 0.06% C, 8.2% Mn, 14.5% Cr, 9.1% Ni, 0.84% ​​Cu, 2.3% Co, 0.27% N, 1.7% Ce, and the balance Fe, weigh pure Fe, Fe-C master alloy, Fe-Mn master alloy, Fe-Cr master alloy, Fe-Ni master alloy, Fe-Cu master alloy, Fe-Ce master alloy, Fe-Co master alloy, and Fe-N master alloy. After removing the surface oxide scale by polishing with 200-grit sandpaper, preheat the mixture and then put the raw materials into a vacuum smelting furnace for conventional steelmaking processes. After smelting, LF-RH refining is performed to obtain the melt to be tested. The content of each element in the melt to be tested is measured using a content analysis device. After adjusting the content deviation of the melt to be tested to be less than 10% from the preset content, the alloy melt is obtained.

[0053] S2. After casting the alloy melt into an alloy billet, the alloy billet is held in a vacuum environment at 870℃ for 4 hours and then cooled to room temperature in the furnace to obtain an annealed alloy material. The annealed alloy material is then heated to 1000℃ from room temperature at a rate of 8℃ / min in a vacuum environment and held for 3 hours, and then cooled to room temperature in the furnace to obtain a normalized alloy material. In a vacuum environment, the normalized alloy material is heated to 950℃ from room temperature at a rate of 8℃ / min and held for 6 hours, and then cooled to 250℃ in the furnace. It is then quickly removed and oil-cooled to room temperature to obtain a quenched alloy material. In a vacuum environment, a quenched alloy material is heated from room temperature to 650°C at a rate of 8°C / min and held for 3 hours before being cooled to room temperature in the furnace to obtain a tempered alloy material. The tempered alloy material is then transferred from room temperature to a vacuum environment at 850°C within 3 seconds and held for 3 hours before being oil-cooled to room temperature to obtain a precursor material. The precursor material is then transferred from room temperature to a vacuum environment at 500°C within 3 seconds and held for 5 hours before being cooled to room temperature in the furnace to obtain an alloy material. The alloy material is then transferred to a vacuum environment at 1290°C and held for 52 hours before being oil-cooled to room temperature to obtain a hydrogen-resistant stainless steel.

[0054] Example 5

[0055] This embodiment 5 provides a method for preparing a Y-containing hydrogen embrittlement resistant stainless steel, including the following steps:

[0056] S1. Based on the preset contents of 0.06% C, 8.2% Mn, 14.5% Cr, 9.1% Ni, 0.84% ​​Cu, 2.3% Co, 0.27% N, 1.3% Y, and the balance Fe, weigh pure Fe, Fe-C master alloy, Fe-Mn master alloy, Fe-Cr master alloy, Fe-Ni master alloy, Fe-Cu master alloy, Fe-Y master alloy, Fe-Co master alloy, and Fe-N master alloy. After removing the surface oxide scale by polishing with 200-grit sandpaper, preheat the mixture and then put the raw materials into a vacuum smelting furnace for conventional steelmaking processes. After smelting, LF-RH refining is performed to obtain the melt to be tested. The content of each element in the melt to be tested is measured using a content analysis device. After adjusting the content deviation of the melt to be tested to be less than 10% from the preset content, the alloy melt is obtained.

[0057] S2. After casting the alloy melt into an alloy billet, the alloy billet is held in a vacuum environment at 870℃ for 4 hours and then cooled to room temperature in the furnace to obtain an annealed alloy material. The annealed alloy material is then heated to 1000℃ from room temperature at a rate of 8℃ / min in a vacuum environment and held for 3 hours, and then cooled to room temperature in the furnace to obtain a normalized alloy material. In a vacuum environment, the normalized alloy material is heated to 950℃ from room temperature at a rate of 8℃ / min and held for 6 hours, and then cooled to 250℃ in the furnace. It is then quickly removed and oil-cooled to room temperature to obtain a quenched alloy material. In a vacuum environment, a quenched alloy material is heated from room temperature to 650°C at a rate of 8°C / min and held for 3 hours before being cooled to room temperature in the furnace to obtain a tempered alloy material. The tempered alloy material is then transferred from room temperature to a vacuum environment at 850°C within 3 seconds and held for 3 hours before being oil-cooled to room temperature to obtain a precursor material. The precursor material is then transferred from room temperature to a vacuum environment at 500°C within 3 seconds and held for 5 hours before being cooled to room temperature in the furnace to obtain an alloy material. The alloy material is then transferred to a vacuum environment at 1290°C and held for 52 hours before being oil-cooled to room temperature to obtain a hydrogen-resistant stainless steel.

[0058] Example 6

[0059] This embodiment 6 provides a method for preparing a hydrogen embrittlement resistant stainless steel containing La and Y, including the following steps:

[0060] S1. Based on the preset contents of 0.06% C, 8.2% Mn, 14.5% Cr, 9.1% Ni, 0.84% ​​Cu, 2.3% Co, 0.27% N, 0.8% La, 0.7% Y, and the balance Fe, weigh pure Fe, Fe-C master alloy, Fe-Mn master alloy, Fe-Cr master alloy, Fe-Ni master alloy, Fe-Cu master alloy, Fe-La master alloy, Fe-Y master alloy, Fe-Co master alloy, and Fe-N master alloy. After removing the surface oxide scale by polishing with 200-grit sandpaper, preheat the mixture and then put the raw materials into a vacuum smelting furnace for conventional steelmaking processes. After smelting, LF-RH refining is performed to obtain the melt to be tested. The content of each element in the melt to be tested is measured using a content analysis device. After adjusting the content deviation of the melt to be tested to be less than 10% from the preset content, the alloy melt is obtained.

[0061] S2. After casting the alloy melt into an alloy billet, the alloy billet is held in a vacuum environment at 870℃ for 4 hours and then cooled to room temperature in the furnace to obtain an annealed alloy material. The annealed alloy material is then heated to 1000℃ from room temperature at a rate of 8℃ / min in a vacuum environment and held for 3 hours, and then cooled to room temperature in the furnace to obtain a normalized alloy material. In a vacuum environment, the normalized alloy material is heated to 950℃ from room temperature at a rate of 8℃ / min and held for 6 hours, and then cooled to 250℃ in the furnace. It is then quickly removed and oil-cooled to room temperature to obtain a quenched alloy material. In a vacuum environment, a quenched alloy material is heated from room temperature to 650°C at a rate of 8°C / min and held for 3 hours before being cooled to room temperature in the furnace to obtain a tempered alloy material. The tempered alloy material is then transferred from room temperature to a vacuum environment at 850°C within 3 seconds and held for 3 hours before being oil-cooled to room temperature to obtain a precursor material. The precursor material is then transferred from room temperature to a vacuum environment at 500°C within 3 seconds and held for 5 hours before being cooled to room temperature in the furnace to obtain an alloy material. The alloy material is then transferred to a vacuum environment at 1290°C and held for 52 hours before being oil-cooled to room temperature to obtain a hydrogen-resistant stainless steel.

[0062] Comparative Example 1

[0063] Comparative Example 1 provides a method for preparing a hydrogen embrittlement-resistant stainless steel without RE elements, comprising the following steps:

[0064] S1. Based on the preset contents of 0.06% C, 9% Mn, 14% Cr, 9% Ni, 0.9% Cu, 2.3% Co, 0.3% N and the balance Fe, weigh pure Fe, Fe-C master alloy, Fe-Mn master alloy, Fe-Cr master alloy, Fe-Ni master alloy, Fe-Cu master alloy, Fe-Co master alloy and Fe-N master alloy. After removing the surface oxide scale by polishing with 200-grit sandpaper, preheat, and then put the raw materials into a vacuum smelting furnace for conventional steelmaking process, and then refine them by LF-RH to obtain the melt to be tested. Use content analysis equipment to measure the content of each element in the melt to be tested, and adjust the content deviation of the melt to be tested to be less than 10% of the preset content to obtain the alloy melt.

[0065] S2. After casting the alloy melt into an alloy billet, the alloy billet is held in a vacuum environment at 850°C for 5 hours and then cooled to room temperature in the furnace to obtain an annealed alloy material. The annealed alloy material is then heated to 980°C from room temperature at a rate of 10°C / min in a vacuum environment and held for 5 hours, and then cooled to room temperature in the furnace to obtain a normalized alloy material. In a vacuum environment, the normalized alloy material is heated to 930°C from room temperature at a rate of 10°C / min and held for 8 hours, and then cooled to 270°C in the furnace. It is then quickly removed and oil-cooled to room temperature to obtain a quenched alloy material. In a vacuum environment, a quenched alloy material is heated from room temperature to 630°C at a rate of 10°C / min and held for 5 hours before being cooled to room temperature in the furnace to obtain a tempered alloy material. The tempered alloy material is then transferred from room temperature to a vacuum environment at 820°C within 3 seconds and held for 2 hours before being oil-cooled to room temperature to obtain a precursor material. The precursor material is then transferred from room temperature to a vacuum environment at 470°C within 3 seconds and held for 3 hours before being cooled to room temperature in the furnace to obtain an alloy material. The alloy material is then transferred to a vacuum environment at 1260°C and held for 50 hours before being oil-cooled to room temperature to obtain a hydrogen-resistant stainless steel.

[0066] Comparative Example 2

[0067] Comparative Example 2 provides a method for preparing a hydrogen embrittlement-resistant stainless steel containing La, Ce, and Y, comprising the following steps:

[0068] S1. Based on the preset contents of 0.06% C, 8.2% Mn, 14.5% Cr, 9.1% Ni, 0.84% ​​Cu, 2.3% Co, 0.27% N, 0.4% La, 0.56% Ce, 0.43% Y, and the balance Fe, weigh pure Fe, Fe-C master alloy, Fe-Mn master alloy, Fe-Cr master alloy, Fe-Ni master alloy, Fe-Cu master alloy, Fe-La master alloy, Fe-Ce master alloy, Fe-Y master alloy, Fe-Co master alloy, and Fe-N master alloy. After removing the surface oxide scale by polishing with 200-grit sandpaper and preheating, put the raw materials into a vacuum smelting furnace for conventional steelmaking process smelting, and then perform LF-RH refining to obtain the melt to be tested. Use content analysis equipment to measure the content of each element in the melt to be tested, and adjust the content deviation of the melt to be tested to be less than 10% of the preset content to obtain the alloy melt.

[0069] S2. After casting the alloy melt into an alloy billet, the alloy billet is held in a vacuum environment at 870℃ for 4 hours and then cooled to room temperature in the furnace to obtain an annealed alloy material. The annealed alloy material is then heated to 1000℃ from room temperature at a rate of 8℃ / min in a vacuum environment and held for 3 hours, and then cooled to room temperature in the furnace to obtain a normalized alloy material. In a vacuum environment, the normalized alloy material is heated to 950℃ from room temperature at a rate of 8℃ / min and held for 6 hours, and then cooled to 250℃ in the furnace. It is then quickly removed and oil-cooled to room temperature to obtain a quenched alloy material. In a vacuum environment, the quenched alloy material is heated to 650℃ from room temperature at a rate of 8℃ / min and held for 3 hours, and then cooled to room temperature in the furnace to obtain a tempered alloy material. The tempered alloy material is transferred from room temperature to a vacuum environment at 850℃ within 3 seconds and held for 3 hours, and then oil-cooled to room temperature to obtain a hydrogen-resistant stainless steel.

[0070] Performance testing

[0071] The hydrogen embrittlement-resistant stainless steels prepared in Examples 1 to 6 and Comparative Examples 1 to 2 were subjected to room temperature tensile tests according to GB / T228.1-2010. The tests were conducted on a Zongheng Sansi electronic universal testing machine at a tensile rate of 0.5 mm / min. Each group was repeated three times and the average value was taken. The results are shown in Table 1. The hydrogen embrittlement-resistant stainless steels prepared in Examples 1 to 6 and Comparative Examples 1 to 2 were also subjected to room temperature tensile tests after being charged with hydrogen in a hydrogen environment of 25°C and 70 MPa. Each group was repeated three times and the average value was taken. The test results are shown in Table 1.

[0072] Table 1. Hydrogen embrittlement resistance of hydrogen-resistant stainless steel

[0073]

[0074]

[0075] As can be seen from Table 1, when the stainless steel contains La, Ce and Y at the same time, the mechanical properties and resistance to hydrogen embrittlement of the stainless steel can be improved simultaneously through the synergistic effect of the three elements. As can be seen from Comparative Example 1 and Example 2, multiple solution treatments during the preparation of stainless steel can effectively improve the mechanical properties of stainless steel and significantly improve its resistance to hydrogen embrittlement. This is because it can further reduce the σ phase in the stainless steel.

[0076] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A method for preparing hydrogen-embrittled stainless steel, characterized in that, Includes the following steps: Pure Fe, Fe-C master alloy, Fe-Mn master alloy, Fe-Cr master alloy, Fe-Ni master alloy, Fe-Cu master alloy, Fe-Re master alloy, Fe-Co master alloy, and Fe-N master alloy are smelted in a vacuum smelting furnace using steelmaking processes, followed by LF+RH refining to obtain an alloy melt; the RE in the Fe-Re master alloy includes at least one of La, Ce, and Y; The alloy molten metal is cast into an alloy billet. Under vacuum (800-900℃) or in an inert atmosphere (850-900℃), the billet is held for 4-5 hours and then cooled to room temperature in a furnace to obtain an annealed alloy material. Under vacuum or inert atmosphere, the annealed alloy material is uniformly heated to 950-1000℃ and held for 3-5 hours, then cooled to room temperature in a furnace to obtain a normalized alloy material. Under vacuum or inert atmosphere, the normalized alloy material is uniformly heated to 900-950℃ and held for 6-8 hours, then cooled to 250-300℃ in a furnace, and then water-cooled or oil-cooled to room temperature to obtain a quenched alloy material. Under an ambient or inert atmosphere, the quenched alloy material is uniformly heated to 600-650℃ and held for 3-5 hours, then cooled to room temperature in the furnace to obtain a tempered alloy material. The tempered alloy material is then transferred from room temperature to a vacuum environment at 800-850℃ within 3-5 seconds, held for 2-3 hours, and then oil-cooled to room temperature to obtain a precursor material. The precursor material is then transferred from room temperature to a vacuum environment at 450-500℃ within 3-5 seconds, held for 3-5 hours, and then cooled to room temperature in the furnace to obtain an alloy material. The alloy material is then placed in a vacuum environment at 1250-1300℃ for 48-55 hours and oil-cooled to room temperature to obtain a hydrogen-resistant stainless steel. The hydrogen embrittlement resistant stainless steel comprises, by weight percentage, the following elements: 0.05-0.08% C, 7-9% Mn, 13-16% Cr, 8-10% Ni, 0.8-1% Cu, 2-3% Co, 0.2-0.4% N, 1-2% RE, 0.01-0.05% impurities, and the balance Fe; wherein the RE includes at least one of La, Ce, and Y.

2. The preparation method according to claim 1, characterized in that, The process of obtaining an alloy melt through LF+RH refining includes: obtaining a mixed melt after LF+RH refining, measuring and adjusting the content of each element in the mixed melt, and then obtaining an alloy melt.

3. The preparation method according to claim 1, characterized in that, During normalizing, the heating rate of the annealed alloy material is 8-10℃ / min during the process of uniformly heating.

4. The preparation method according to claim 1, characterized in that, During the quenching process, the heating rate of the normalized alloy material is 8-10℃ / min during the uniform heating process.

5. The preparation method according to claim 1, characterized in that, During tempering, the quenched alloy material is heated uniformly at a rate of 8-10℃ / min.

6. The preparation method according to claim 1, characterized in that, When the RE is a mixture of La and Ce, the hydrogen embrittlement resistant stainless steel comprises the following elements by mass percentage: 0.06-0.07% C, 8-9% Mn, 14-15% Cr, 8-9% Ni, 0.9-1% Cu, 2.3-2.5% Co, 0.3-0.4% N, 0.6-0.8% La, 0.5-0.6% Ce, 0.01-0.05% impurities and balance Fe; And / or, when the RE is a mixture of La, Ce and Y, the hydrogen embrittlement resistant stainless steel comprises, by mass percentage: 0.05-0.06% C, 7.5-8.5% Mn, 13.5-15.5% Cr, 8.4-9.7% Ni, 0.8-0.9% Cu, 2-2.5% Co, 0.25-0.3% N, 0.3-0.5% La, 0.5-0.7% Ce, 0.4-0.5% Y, 0.01-0.05% impurities and the balance Fe.

7. A hydrogen-resistant stainless steel prepared by the method according to any one of claims 1 to 6, used in the molding of hydrogen transport equipment, characterized in that, The hydrogen transport equipment includes at least one of a storage tank and a transport pipeline.

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