Steel for high-pressure hydrogen storage container and preparation method thereof

Abstract

The invention discloses steel for a high-pressure hydrogen storage container and a preparation method of the steel, belongs to the technical field of steel for the high-pressure hydrogen storage container, and solves the problems that in the prior art, the performance is poor when the steel for the hydrogen storage container is used for large-size parts, and the low-temperature toughness of the steel for the hydrogen storage container is poor. The steel for the high-pressure hydrogen storage container comprises the following components in percentage by mass: 0.13%-0.16% of C, 0.1%-0.25% of Si, 0.3%-1.2% of Mn, less than or equal to 0.010% of P, less than or equal to 0.005% of S, 0.30%-1.0% of Mo, 0.4%-1.2% of Cr, 0.030%-0.10% of V, 1.0%-3.0% of Ni, 0.02%-0.06% of Al and the balance of Fe and inevitable impurities. The steel for the high-pressure hydrogen storage container has good comprehensive performance.

Description

Technical Field

[0001] The present invention relates to the technical field of steel for high-pressure hydrogen storage containers, and in particular to steel for high-pressure hydrogen storage containers and a preparation method thereof. Background Art

[0002] As a green and clean energy, hydrogen energy is of great significance to reducing carbon emissions and promoting carbon peak and carbon neutrality. In view of the current engineering needs for large-scale, safe and economical storage and transportation of hydrogen energy, it is of great significance to develop steel for high-pressure hydrogen storage containers. The tensile strength of steel for high-pressure hydrogen storage containers is a key indicator for determining the allowable stress and the wall thickness of the container. The current tensile strength level of spherical tank steel is up to 610MPa, and the matching forgings are 600MPa. Flanges are important connectors for high-pressure hydrogen storage container steel. If the flange forgings are increased to above 750MPa, the container steel can be increased to about 800MPa, and the container wall thickness will be reduced by about 25%, thereby greatly reducing the weight and manufacturing cost of the hydrogen storage container. High-pressure hydrogen storage containers may suffer from hydrogen embrittlement failure, so the material of high-pressure hydrogen storage containers should also have excellent toughness to reduce the possibility of hydrogen embrittlement.

[0003] The chemical composition, structure, carbides, dislocations, etc. of steel will affect the sensitivity to hydrogen embrittlement. As the strength of forgings increases, the hydrogen embrittlement sensitivity becomes more significant, and higher requirements are placed on the structure and performance. In the prior art, the tensile strength range of steel for hydrogen storage containers covers 350 to 900 MPa, but the low-temperature toughness is generally low, with the impact energy at -40°C being less than 100 J. In addition, the existing steel for hydrogen storage containers has poor performance when used for large-size parts. Therefore, how to improve the low-temperature toughness of steel for large-size high-pressure hydrogen storage containers has become an urgent problem to be solved. Summary of the invention

[0004] In view of the above situation, the present invention aims to provide a steel for high-pressure hydrogen storage containers and a preparation method thereof, so as to solve one of the following technical problems: the existing steel for hydrogen storage containers has poor performance when used for large-size parts, and the low-temperature toughness of the steel for hydrogen storage containers is poor.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] On the one hand, the present invention provides a steel for a high-pressure hydrogen storage container. The components of the steel for a high-pressure hydrogen storage container include, by mass percentage: C: 0.13% to 0.16%, Si: 0.1% to 0.25%, Mn: 0.3% to 1.2%, P: ≤0.010%, S: ≤0.005%, Mo: 0.30% to 1.0%, Cr: 0.4% to 1.2%, V: 0.030% to 0.10%, Ni: 1.0% to 3.0%, Al: 0.02% to 0.06%, and the balance is Fe and unavoidable impurities.

[0007] Furthermore, in the composition of the steel for high-pressure hydrogen storage containers, the C+Mn content is controlled to be 0.4% to 1.3%.

[0008] Furthermore, in the composition of the steel for high-pressure hydrogen storage containers, Mo / V is controlled to be 5-10.

[0009] Furthermore, in the composition of steel for high-pressure hydrogen storage containers, Cr / Ni is controlled to be 0.2 to 0.5.

[0010] Furthermore, in the composition of the steel for high-pressure hydrogen storage containers, Cr+Ni+Mo is greater than 2.5%.

[0011] Furthermore, the components of the steel for high-pressure hydrogen storage containers include, by mass percentage: C: 0.13% ~ 0.16%, Si: 0.11% ~ 0.23%, Mn: 0.4% ~ 1.1%, P: ≤ 0.010%, S: ≤ 0.005%, Mo: 0.4% ~ 1.0%, Cr: 0.5% ~ 1.2%, V: 0.04% ~ 0.1%, Ni: 1.0% ~ 3.0%, Al: 0.02% ~ 0.06%, and the balance is Fe and unavoidable impurities.

[0012] The present invention also provides a method for preparing steel for a high-pressure hydrogen storage container, which is used to prepare the steel for a high-pressure hydrogen storage container. The preparation method comprises:

[0013] Step 1: smelting and pouring to obtain a billet or ingot;

[0014] Step 2: forging the billet or ingot after high temperature homogenization treatment;

[0015] Step 3: After normalizing the forging, perform quenching and high-temperature tempering to obtain steel for high-pressure hydrogen storage containers.

[0016] Furthermore, the specific steps of step 2 include: heating the billet or ingot to 1150-1250° C. in a heating furnace and keeping the temperature.

[0017] Furthermore, step 3 includes:

[0018] Step 3-1, normalizing: after forging, normalizing treatment is performed at 900-960°C, heat preservation, and air cooling to room temperature;

[0019] Step 3-2, quenching: heat the forging after normalizing to 860-910°C, keep warm, and then water cool to room temperature;

[0020] Step 3-3, high temperature tempering: then keep at 600-700°C and then air cool to room temperature.

[0021] Furthermore, in step 2, the holding time t1 and the thickness d of the casting billet or ingot meet the following relationship:

[0022] The holding temperature is below 1180°C, t1 = 37 to 43 days;

[0023] The holding temperature is greater than 1180°C, t1=26-33d; the unit of d is millimeter, and the unit of t1 is second.

[0024] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0025] a) The steel for high-pressure hydrogen storage containers provided by the present invention uses V microalloying by precisely controlling the mass percentage of elements such as C, Si, Mn, V, and Mo in the steel, combined with controlling the synergistic quantitative relationship of different elements, to inhibit the growth of recrystallized grains during heating, thereby refining austenite grains, generating a dispersed second phase during tempering, and improving strength through grain refinement and second phase strengthening; the carbide precipitation phase acts as an irreversible hydrogen trap to improve hydrogen resistance; by adding more Mo elements, the hardenability is improved, and at the same time, it is beneficial to promote the precipitation of second phase carbides; by increasing Ni The low-temperature toughness of the test steel is improved by increasing the content of Cr elements; adding Cr elements further improves the hardenability, matches Mo and Ni, improves the core structure of large-section forgings, and thus improves the core mechanical properties; increasing the content of elements with hydrogen resistance such as Mo, Ni and Cr is conducive to improving the hydrogen resistance of forgings; and combining quenching + high-temperature tempering process to ensure that the steel structure is tempered troostite + a dispersed and refined second phase distributed on the matrix, ensuring that the steel for high-pressure hydrogen storage containers has a high strength level while also having excellent toughness and good hydrogen embrittlement resistance. It is ensured that the steel of the present invention can meet excellent mechanical properties.

[0026] b) The present invention obtains "tempered troostite + dispersed and refined second phase distributed on the matrix" by precisely controlling the composition and process. The tempered troostite as the matrix structure has good strength-toughness-plasticity matching and excellent hydrogen embrittlement resistance, excellent low-temperature toughness, and delayed crack propagation. The dispersed precipitated second phase can act as an irreversible hydrogen trap to absorb H, and at the same time pin the grain boundaries during the quenching process, refine the grains, and improve the hydrogen embrittlement resistance.

[0027] c) The steel for high-pressure hydrogen storage containers of the present invention has good comprehensive properties, yield strength ≥660MPa (e.g. 660-690MPa), tensile strength ≥820MPa (e.g. 821-850MPa), elongation ≥21% (e.g. 21%-23%), -40°C impact energy ≥190J (e.g. 195-230J), high strength and toughness, and excellent performance. The hydrogen resistance is tested with reference to GB / T 39039-2020 standard, and the relative section shrinkage is 78%-86%.

[0028] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the contents particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings are only for the purpose of illustrating specific embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0030] Figure 1 The microstructure diagram of the steel of Example 1 of the present invention;

[0031] Figure 2 The microstructure diagram of the steel of Example 2 of the present invention;

[0032] Figure 3 This is a microstructure diagram of the steel of Example 3 of the present invention.

[0033] Figure 4 This is a microstructure diagram of the steel of Example 4 of the present invention.

[0034] Figure 5 This is a microstructure diagram of the steel of Example 5 of the present invention. DETAILED DESCRIPTION

[0035] Preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used to explain the principles of the present invention together with the embodiments of the present invention.

[0036] The invention provides a steel for a high-pressure hydrogen storage container. The components of the steel for a high-pressure hydrogen storage container include, by mass percentage: C: 0.13%-0.16%, Si: 0.1%-0.25%, Mn: 0.3%-1.2%, P: ≤0.010%, S: ≤0.005%, Mo: 0.30%-1.0%, Cr: 0.4%-1.2%, V: 0.030%-0.10%, Ni: 1.0%-3.0%, Al: 0.02%-0.06%, and the balance is Fe and unavoidable impurities.

[0037] Specifically, in the composition of steel for high-pressure hydrogen storage containers, the C+Mn content is controlled to be 0.4% to 1.3%; Mo / V is controlled between 5 and 10; Cr / Ni is guaranteed to be between 0.2 and 0.5, and Cr+Ni+Mo is greater than 2.5%.

[0038] The following is a detailed description of the effects and dosage of the components in the present invention:

[0039] C: Carbon is a typical interstitial solid solution strengthening element. Increasing the carbon content in the alloy is an effective way to improve the strength of the alloy. However, too high a C content will reduce the plastic toughness of the steel. At the same time, too much C and Mn will cause banded structure in the steel. Too high a C content will lead to excessive strength. The higher the strength, the higher the sensitivity to hydrogen-induced cracking, which is not conducive to the resistance to hydrogen embrittlement. Among them, the increase of Mn will aggravate the generation of hydrogen embrittlement. Therefore, the Mn content needs to be controlled when the C content is increased. Therefore, the C content of the present invention is controlled at 0.13% to 0.16%, and the C+Mn content is controlled at 0.4% to 1.3%.

[0040] Si: Si is a deoxidizer in steelmaking, but excessive silicon is detrimental to the steel's resistance to hydrogen sulfide corrosion. Therefore, the content of Si in the present invention is controlled at 0.1% to 0.25%.

[0041] Mn: Adding Mn can reduce the martensite transformation temperature M s However, too high Mn content makes low-temperature toughness unfavorable and increases hydrogen embrittlement sensitivity. Therefore, low Mn design is adopted, and good toughness is obtained by further controlling the C content. Therefore, the Mn content is controlled at 0.3% to 1.2%.

[0042] P: P is an impurity in steel and is not conducive to toughness. In the present invention, the P content is controlled to be ≤0.010%.

[0043] S: S seriously deteriorates the corrosion resistance and toughness of steel and is prone to form MnS inclusions that deteriorate the performance. In the present invention, its content is controlled to be ≤0.005%.

[0044] Mo: Mo can significantly improve the hardenability of the pipe, ensuring that a complete martensitic structure can be obtained when quenching 200mm thick steel; at the same time, the Mo element improves the tempering stability of the steel during high-temperature tempering, and is conducive to the precipitation of the second phase carbide, avoiding the steel from losing strength too quickly during high-temperature tempering and failing to meet the requirements, ensuring that the steel has good comprehensive mechanical properties at a higher strength. At the same time, by adding Mo elements to improve the resistance to temper brittleness, Mo is also a good uniform corrosion resistance element, reducing H + The amount of corrosion that penetrates into the steel material improves the hydrogen embrittlement resistance in a phase-change manner. It is found that the Mo / V ratio is kept between 5 and 10, and the precipitated (Mo, V) C serves as an effective hydrogen trap. In the present invention, the Mo content is controlled to be 0.30% to 1.0%.

[0045] Cr: Cr is an element that improves hardenability. It works together with Mo to improve hardenability and ensure that a complete martensitic structure is obtained during quenching. At the same time, Cr is also a corrosion-resistant element. It matches Mo and Ni. The total amount of Cr+Ni+Mo is greater than 2.5%, which improves the core structure of large-section forgings, thereby improving the core mechanical properties. Too high Cr content is not good for welding performance. Therefore, the Cr content is controlled at 0.4% to 1.2%.

[0046] V: V can precipitate VC during quenching, refine the grains by pinning the grain boundaries, and form carbides during the heat treatment and tempering process to achieve precipitation strengthening. It can also improve the high temperature tempering resistance and improve the strength by fine grain strengthening and second phase strengthening. In addition, since V combines with C to precipitate carbides, the solid solution C content in the steel is reduced, the appearance of banded structure is reduced, and at the same time, it acts as an irreversible hydrogen trap to reduce the sensitivity to hydrogen embrittlement, and Mo / V is guaranteed to be between 5 and 10. However, when the V content in the steel is too high, the toughness of the material will be significantly reduced. Therefore, V microalloying is used to inhibit the growth of recrystallized grains during heating to refine the austenite grains. In the present invention, the V content is controlled to be 0.03% to 0.10%.

[0047] Ni: Ni expands the austenite phase region, and Ni can cooperate with Cr and Mo to improve hardenability and corrosion resistance. The low-temperature toughness of steel is improved by increasing the Ni content. In the present invention, the Ni content is controlled to be 1.0% to 3.0%.

[0048] Al: Aluminum is a commonly used deoxidizer in steel. Adding a small amount of aluminum to steel can refine the grains and improve impact toughness. Aluminum also has antioxidant and corrosion resistance, and has a good effect on resisting H2S medium corrosion. The price of aluminum is relatively cheap, but excessive aluminum will reduce welding performance and cutting performance. Therefore, the Al content is controlled at 0.02% to 0.06%.

[0049] In order to further improve the comprehensive performance of the above-mentioned steel for high-pressure hydrogen storage containers, the components of the above-mentioned steel for high-pressure hydrogen storage containers include, by mass percentage: C: 0.13%~0.16%, Si: 0.11%~0.23%, Mn: 0.4%~1.1%, P: ≤0.010%, S: ≤0.005%, Mo: 0.4%~1.0%, Cr: 0.5%~1.2%, V: 0.04%~0.1%, Ni: 1.0%~3.0%, Al: 0.02%~0.06%, and the balance is Fe and unavoidable impurities.

[0050] Specifically, in the components of steel for high-pressure hydrogen storage containers, the C+Mn content is controlled at 0.5% to 1.3%; Mo / V needs to be guaranteed to be between 6 and 10; Cr / Ni is guaranteed to be between 0.25 and 0.5, and the total amount of Cr+Ni+Mo is greater than 2.5%, for example, Cr+Ni+Mo is 3% to 6%.

[0051] The above-mentioned steel for high-pressure hydrogen storage containers can also ensure excellent performance when used for large-size parts. For example, the thickness of the parts can reach 180mm to 220mm.

[0052] The room temperature microstructure of the above-mentioned steel for high-pressure hydrogen storage containers includes tempered bainite + a dispersed and refined second phase distributed on the matrix; wherein the second phase mainly includes (Mo,V)C, VC, MoC, Cr7C3, etc.; the grain size is less than 20μm, for example, 10-20μm; the size of the second phase particles is basically nanometer-level, and is mainly spherical or short rods, for example, the size of the second phase is 5-30nm.

[0053] Specifically, the mass fraction of the second phase is about 0.05% to 0.14%.

[0054] The present invention also provides a method for preparing the steel for the high-pressure hydrogen storage container, comprising:

[0055] Step 1: smelting and pouring to obtain a billet or ingot;

[0056] Step 2: forging the billet or ingot after high temperature homogenization treatment;

[0057] Step 3: After normalizing the forging, perform quenching and high-temperature tempering to obtain steel for high-pressure hydrogen storage containers.

[0058] Specifically, in the above step 1, a converter, an electric furnace or an induction furnace may be used for smelting, and continuous casting or die casting may be used to produce a cast billet or an ingot. The thickness of the cast billet or ingot may be more than 300 mm.

[0059] Specifically, the role of the above step 2 is to ensure that all alloy elements are dissolved and exist in the matrix in the form of solid solution. Considering that the holding temperature is too high or the holding time is too long, the austenite grains will grow excessively or even overheat, affecting the final performance of the material; the holding temperature is too low or the holding time is too short, resulting in the steel not being able to be completely austenitized or the alloy elements are not fully dissolved, and the steel composition is uneven, affecting the performance. Therefore, the specific steps of controlling the above step 2 include: heating the billet or ingot to 1150-1250℃ in a heating furnace for insulation, and forging after it comes out of the furnace.

[0060] Specifically, in the above step 2, the holding time t1 and the thickness d of the casting billet or ingot meet the following relationship:

[0061] When the holding temperature is below 1180°C, t1=37-43d, where d is in millimeters (mm) and t1 is in seconds (s); preferably, t1=40d;

[0062] When the insulation temperature is greater than 1180°C, t1=26-33d, the unit of d is millimeter (mm), and the unit of t1 is second (s); preferably, t1=30d.

[0063] Specifically, the specific steps of the above step 3 include:

[0064] Step 3-1, normalizing: after forging, normalizing treatment is performed at 900-960°C, heat preservation, and air cooling to room temperature;

[0065] Step 3-2, quenching: heat the forging after normalizing to 860-910°C, keep warm, and then water cool to room temperature;

[0066] Step 3-3, high temperature tempering: then keep at 600-700°C and then air cool to room temperature.

[0067] Specifically, in the above step 3-1, the holding time t2 and the thickness H of the blank meet the following relationship: t2=0.8-1.2H, where H is in millimeters (mm) and t2 is in minutes (min). Preferably, t2=1H.

[0068] Specifically, in the above step 3-2, the heat preservation time t3 and the thickness H of the blank meet the following relationship: t3=0.8-1.2H, the unit of H is millimeter (mm), and the unit of t3 is minute (min). Preferably, t3=1H.

[0069] Specifically, in the above step 3-3, the heat preservation time t4 and the thickness H of the blank meet the following relationship: t4=1.3-1.7H, the unit of H is millimeter (mm), and the unit of t4 is minute (min). Preferably, t4=1.5H.

[0070] Specifically, in the above step 3-2, quenching is to heat the forging to a complete austenitization temperature of 860-910°C and keep it warm for 3-4.5 hours to ensure that the tube structure is completely austenitized, and at the same time, the second phase particles VC are precipitated, pinning the grain boundaries to prevent the grain boundaries from growing, which plays a role in refining the grains and improving the hydrogen embrittlement resistance. Then quench to room temperature to obtain a complete martensitic structure. Although the grain boundaries do not grow significantly due to the pinning of VC precipitation, if the temperature is too high or the holding time is too long, it will have little effect on the final performance and reduce the production efficiency; if the holding temperature is too low or the holding time is too short, the steel cannot be completely austenitized, and the structure of different positions of the forging is uneven, which affects the performance.

[0071] Specifically, in the above step 3-3, the tempering temperature is too high, and the material enters the two-phase region, resulting in the generation of some M / A islands during the cooling process, which reduces the low-temperature toughness. If the holding time is too long, the matrix softens severely, and the second-phase particles are significantly coarsened, and the material strength is significantly reduced; if the tempering temperature is too low, the second-phase particles are insufficiently driven to precipitate, and cannot serve as an effective hydrogen trap; if the holding time is too short, the matrix dislocation density is high, and the low-temperature toughness of the material is less than 100J, which cannot meet the requirements. Therefore, the high-temperature tempering temperature is controlled at 600-700°C, and air-cooled to room temperature after holding for 4-6.5 hours. The quenched martensite structure is transformed into a fine tempered troostite structure, and the comprehensive mechanical properties and hydrogen embrittlement resistance are significantly improved.

[0072] Specifically, if the heating rate is too slow, the actual holding time will be too long, which is not good for the strength; if the heating rate is too fast, the temperature difference between the surface and the core will be too large, and the holding time needs to be extended, which will reduce the performance. Therefore, the forgings are placed in the tempering furnace and the temperature is increased to 600-700℃ at a rate of 1-4℃ / S.

[0073] Specifically, in the above step 3-3, the room temperature microstructure of the steel for high-pressure hydrogen storage containers includes tempered bainite + a dispersed and refined second phase distributed on the matrix; wherein the second phase mainly includes (Mo,V)C, VC, MoC, Cr7C3, etc.; the grain size is less than 20μm, for example, 10 to 20μm; the size of the second phase particles is basically nanometer-scale, and is mainly spherical or short rods, for example, the size of the second phase is 5 to 30nm.

[0074] Specifically, the mass fraction of the second phase is about 0.05% to 0.14%.

[0075] Specifically, in the above step 3, the properties of the steel for high-pressure hydrogen storage containers obtained are as follows: yield strength ≥ 660MPa (e.g. 660-690MPa), tensile strength ≥ 820MPa (e.g. 821-850MPa), elongation ≥ 21% (e.g. 21%-23%), -40°C impact energy ≥ 190J (e.g. 195-230J), high strength and toughness, excellent performance. The hydrogen resistance is tested with reference to the GB / T 39039-2020 standard, and the relative section shrinkage is 78%-86%.

[0076] Examples 1-5

[0077] Embodiments 1-5 of the present invention provide a steel for a high-pressure hydrogen storage container and a preparation method thereof. The components of the steels of Embodiments 1-5 are shown in Table 2 below.

[0078] The method for preparing the steel of Examples 1-5 comprises:

[0079] (1) Use converter steelmaking and continuous casting;

[0080] (2) Three-pier and three-drawing are adopted, and normalizing treatment is performed after forging;

[0081] (3) The forgings after normalizing are subjected to quenching + high temperature tempering treatment.

[0082] The thickness of the ingots of Examples 1 to 3 is 350 mm, the thickness of the ingots of Examples 4 and 5 is 400 mm, the specific preparation process parameters of the steels of Examples 1-5 are shown in Table 1 below, the corresponding components are shown in Table 2, the microstructures are shown in Table 3, the mechanical properties are shown in Table 4, and the relative cross-sectional shrinkage in H2 environment is shown in Table 5. The microstructure of Example 1 is shown in Table 1. Figure 1 As shown, the microstructure of Example 2 is as follows Figure 2 As shown, the microstructure of Example 3 is as follows Figure 3 shown.

[0083] Table 1 Process parameters

[0084]

[0085]

[0086] Table 2 Chemical composition

[0087]

[0088] Table 3 Microstructure

[0089]

[0090]

[0091] Table 4 Mechanical properties

[0092]

[0093] Table 5 Hydrogen resistance

[0094]

[0095] The inventor has conducted a large number of experimental studies during the research process, and now uses some solutions with poor performance as comparative examples.

[0096] Comparative Example 1

[0097] This comparative example provides a steel for a high-pressure hydrogen storage container, the components of which are shown in Table 2 above, and the preparation method is the same as that of Example 1, which will not be repeated here. Among them, Cr, Mo, V, Ni, Mo / V, and Cr / Ni do not meet the design composition range, and the strength thereof does not meet the design requirements.

[0098] Comparative Example 2

[0099] This comparative example provides a steel for a high-pressure hydrogen storage container, the components of which are shown in Table 2 above, and the preparation method is the same as that of Example 1, which will not be repeated here. Among them, C, Mn, Cr / Ni, and C+Mn do not meet the design composition range, and the strength and toughness thereof do not meet the design requirements.

[0100] Comparative Example 3

[0101] This comparative example provides a steel for a pressurized hydrogen storage container, whose components are the same as those in Example 1. In the preparation method, the homogenization temperature is 1100°C, the tempering temperature is 580°C, and the rest is the same as in Example 1. Its low-temperature toughness does not meet the requirements.

[0102] The main performance test results of the comparative steel are shown in Table 5 above.

[0103] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A steel for high-pressure hydrogen storage containers, It is characterized in that The components of the steel for high-pressure hydrogen storage containers include, by mass percentage: C: 0.13% to 0.16%, Si: 0.1% to 0.25%, Mn: 0.3% to 1.2%, P: ≤0.010%, S: ≤0.005%, Mo: 0.30% to 1.0%, Cr: 0.4% to 1.2%, V: 0.030% to 0.10%, Ni: 1.0% to 3.0%, Al: 0.02% to 0.06%, and the balance is Fe and unavoidable impurities.

2. The steel for high-pressure hydrogen storage container according to claim 1, It is characterized in that In the composition of the steel for high-pressure hydrogen storage container, the C+Mn content is controlled to be 0.4% to 1.3%.

3. The steel for high-pressure hydrogen storage container according to claim 1, It is characterized in that In the composition of the steel for high-pressure hydrogen storage container, Mo / V is controlled to be 5-10.

4. The steel for high-pressure hydrogen storage container according to claim 1, It is characterized in that In the composition of the steel for high-pressure hydrogen storage container, Cr / Ni is controlled to be 0.2-0.

5.

5. The steel for high-pressure hydrogen storage container according to claim 1, It is characterized in that In the composition of the steel for high-pressure hydrogen storage container, Cr+Ni+Mo is greater than 2.5%.

6. The steel for high-pressure hydrogen storage container according to claim 1, It is characterized in that The components of the steel for high-pressure hydrogen storage containers include, by mass percentage, C: 0.13% to 0.16%, Si: 0.11% to 0.23%, Mn: 0.4% to 1.1%, P: ≤0.010%, S: ≤0.005%, Mo: 0.4% to 1.0%, Cr: 0.5% to 1.2%, V: 0.04% to 0.1%, Ni: 1.0% to 3.0%, Al: 0.02% to 0.06%, and the remainder is Fe and unavoidable impurities.

7. A method for preparing steel for high-pressure hydrogen storage containers, It is characterized in that The preparation method is used to prepare the steel for high-pressure hydrogen storage container according to any one of claims 1 to 6, and the preparation method comprises: Step 1: smelting and pouring to obtain a billet or ingot; Step 2: forging the billet or ingot after high temperature homogenization treatment; Step 3: After normalizing the forgings, perform quenching and high-temperature tempering to obtain steel for high-pressure hydrogen storage containers.

8. The preparation method according to claim 7, It is characterized in that The specific steps of step 2 include: heating the billet or ingot to 1150-1250° C. in a heating furnace and keeping the temperature.

9. The preparation method according to claim 7, It is characterized in that The step 3 comprises: Step 3-1, normalizing: after forging, normalizing treatment is performed at 900-960°C, heat preservation, and air cooling to room temperature; Step 3-2, quenching: heat the forging after normalizing to 860-910°C, keep warm, and then water cool to room temperature; Step 3-3, high temperature tempering: then heat preservation at 600-700°C and air cooling to room temperature.

10. The preparation method according to claim 7 or 8, It is characterized in that In step 2, the holding time t1 and the thickness d of the billet or ingot meet the following relationship: The holding temperature is below 1180°C, t1 = 37 to 43 days; The holding temperature is greater than 1180°C, t1=26-33d; the unit of d is millimeter, and the unit of t1 is second.

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