High-strength hydrogen storage container steel plate with excellent resistance to high heat input and method for manufacturing the same

Abstract

The present invention provides a high-strength steel plate for hydrogen storage containers with excellent resistance to high heat input and a method for manufacturing the same. The steel plate comprises the following components by weight: C: 0.08%-0.10%, Si: 0.20%-0.35%, Mn: 1.60%-1.80%, P: ≤0.015%, S: ≤0.005%, Cr: 0.40%-0.50%, Mo: 0.20%-0.30%, Ni: 0.20%-0.40%, V: 0.20%-0.25%, Nb: 0.02%-0.03%, Ti: 0.02%-0.04%, Al: 0.003%-0.005%, Ca: 0.003%-0.005%, with a V / C ratio of ≥2, and the balance being Fe and unavoidable impurities. The production method of the steel plate includes smelting, continuous casting, slab heating, controlled rolling, cooling, and heat treatment. The steel plate with a thickness of (36-60) mm of the present invention has excellent strength and low-temperature impact toughness, and has a uniform and fine structure, and can meet the manufacturing and application requirements of steel plates for pressure vessels.

Description

Technical Field

[0001] The present invention relates to the field of preparation of hydrogen storage container steel plates, and in particular to a tempered high-strength hydrogen storage container steel plate with excellent resistance to high linear energy and a manufacturing method thereof, which is particularly suitable for gas hydrogen storage tanks. Background Art

[0002] In recent years, with the increasing global demand for energy, the demand for renewable energy has continued to rise. To build a cleaner, low-carbon, safer, and more efficient energy system, limit fossil fuel consumption, and implement renewable energy substitution, hydrogen has become a key energy carrier for the effective recycling of renewable energy and is widely used in urban transportation, industrial production, and urban construction. Therefore, the research and development of steel plates for gas-hydrogen storage at various high pressures is extremely important and has become a top priority in hydrogen energy storage.

[0003] Energy input is a crucial process parameter in welding. It refers to the energy delivered to a weld per unit length by the welding power source, also known as heat input, and is generally expressed in kilojoules per centimeter (kJ / cm). Conventional welding heat input is below 50 kJ / cm, with those above 50 kJ / cm generally considered high-energy input welding. Increasing the energy input can improve welding efficiency and shorten the manufacturing cycle. Therefore, high-energy input welding is often used in welding medium-thick steel plates. High-energy input welding allows for a single pass, increasing production efficiency severalfold and significantly reducing production costs. However, high-energy input welding can adversely affect the toughness of the heat-affected zone (HAZ) of traditional low-alloy steels. The HAZ, subjected to the continuous action of the high-temperature deposited metal in the weld, remains at elevated temperatures for extended periods, and cools slowly, leading to severe coarsening of the original austenite grains. This ultimately reduces the steel's low-temperature impact toughness and can even cause weld cracks.

[0004] CN117070855A "Corrosion-resistant ultra-large heat input welding steel plate and its production method", its chemical composition is: Ce: 0.05-0.5%, Sn: 0.05-0.5%, Cu: 0.1-0.5%, Si: 0.1-0.4%, C: ≤ 0.12%, Mn: ≤ 2.0%, and other elements. The Ce and Sn content in its designed composition is relatively high, which is prone to segregation and generates large-sized inclusions. The steel plate is prone to cracks during welding; CN116574981A "A high-quality low-temperature storage In the article "Steel Plate for Oil Tanks and Its Production Method", the chemical composition is designed as follows: C: 0.05-0.07%, Si: 0.10-0.30%, Mn: 1.45-1.55%, Cr: 0.20-0.25%, V: 0.035-0.040%, Ni: 0.15-0.20%, Ti: 0.025-0.030%, and the balance is Fe and other elements. Through controlled rolling and controlled cooling process + tempering heat treatment, the low-temperature impact toughness of the steel plate is only guaranteed to be -20°C. Its applicable environment is limited and it is difficult to overcome the use environment.

[0005] Steel plates for containers are mainly quenched and tempered steel plates. By improving the manufacturing method and adjusting the alloy element content in the steel grade, the hydrogen resistance and the ability to resist high-wire energy welding can be improved. It is urgent to develop quenched and tempered high-strength hydrogen storage container steel plates with excellent resistance to high-wire energy and their manufacturing methods. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention aims to provide a high-strength steel plate for hydrogen storage containers with excellent resistance to high line energy and a method for manufacturing the same. The present invention adopts a composition design combined with a two-stage controlled rolling production process, as well as a quenching and tempering heat treatment, to obtain a steel plate with mechanical properties and mechanical properties that simulate post-weld heat treatment that meet the following requirements: yield strength R eL ≥600MPa, tensile strength R m :720~850MPa, elongation A≥21%, -50℃ low temperature impact toughness KV2≥100J, -50℃ low temperature tensile yield strength R eL ≥620MPa, tensile strength R m :735~880MPa, elongation ≥21%; use high wire energy 100~150kJ / cm to weld steel plates, the yield strength of the heat affected zone (HAZ) R eL ≥650MPa, tensile strength R m : 780-900MPa, elongation ≥19%, -50℃ HAZ impact toughness KV2 ≥80J. (36-60)mm thick steel plates offer excellent strength and low-temperature impact toughness, along with a uniform and fine structure, meeting the manufacturing and application requirements for pressure vessel steel plates.

[0007] The object of the invention is achieved like this:

[0008] A quenched and tempered container steel plate with excellent resistance to high heat input. The chemical composition of the steel used, calculated by mass percentage, is as follows: C: 0.08%-0.10%, Si: 0.20%-0.35%, Mn: 1.60%-1.80%, P: ≤0.015%, S: ≤0.005%, Cr: 0.40%-0.50%, Mo: 0.05%-0.15%, Ni: 0.20%-0.40%, V: 0.20%-0.40%, Nb: 0.02%-0.03%, Ti: 0.02%-0.04%, Al: 0.003%-0.005%, Ca: 0.003%-0.005%, and the balance is Fe and unavoidable impurities.

[0009] Furthermore, the component V / C is ≥2.5.

[0010] Furthermore, the steel plate yield strength R eL ≥600MPa, tensile strength R m : 720~850MPa, elongation ≥21%, -50℃ impact toughness KV2 ≥100J, -50℃ low temperature tensile yield strength R eL ≥620MPa, tensile strength R m :735~880MPa, elongation ≥21%; use high wire energy 100~150kJ / cm to weld steel plates, the yield strength of the heat affected zone (HAZ) R eL ≥650MPa, tensile strength R m : 780~900MPa, elongation ≥19%, -50℃ welding heat affected zone (HAZ) impact toughness KV2 ≥80J.

[0011] Furthermore, the steel plate microstructure is bainite tempered structure + acicular ferrite, the bainite tempered structure accounts for 85-95% of the volume, the acicular ferrite accounts for 5-15% of the volume, the grain size is 8-10, the average size of the composite inclusions is 1-3 μm, and the steel plate thickness is 36-60 mm.

[0012] The reasons for the composition design of the present invention are as follows:

[0013] C:0.08%~0.10%

[0014] Cr, Mo and Ti are the main elements of the present invention. The effects of the above chemical elements are analyzed as follows:

[0015] Carbon forms various carbides with alloying elements in steel, which strengthens the steel and directly increases its strength. However, excessive carbon content can lead to poor toughness, plasticity, and weldability. To ensure that the steel maintains good low-temperature impact toughness, strength, and weldability during use, increased carbon content can easily lead to increased bainite and cementite, affecting toughness. Therefore, to ensure a sufficiently low carbon equivalent and excellent weldability, the carbon content is limited to 0.08% to 0.10%.

[0016] Si: 0.20%~0.35%

[0017] Si is an element that increases carbon activity in steel. In high silicon concentration areas, it can reduce the diffusion flow of carbon into carbides, inhibit the coarsening of carbides, and a certain amount of Si can increase the strength of steel plates, improve the hardenability of steel, and within a certain range can reduce the ductile-brittle transition temperature and improve the plasticity of steel. Therefore, the Si content is limited to 0.20% to 0.35%.

[0018] Mn: 1.60%~1.80%

[0019] Mn acts as a solid solution strengthener in steel. It can dissolve in large quantities in the Fe matrix, increasing the strength and hardness of the steel plate, improving hot workability, preventing hot cracking, and modifying the distribution of sulfides. Increasing the Mn content compensates for the strength loss caused by reduced C content. Within a certain range, Mn content can also improve weld metal toughness and the solubility of Nb and V in the steel. However, excessive Mn content can easily lead to segregation in the steel plate, adversely affecting plasticity and toughness. Therefore, Mn is limited to 1.60% to 1.80%.

[0020] P:≤0.015%

[0021] P is a harmful element in steel, which has a significant impact on low-temperature impact toughness and is also an element that is easily segregated. Therefore, its content should be kept low during the steelmaking process. The present invention controls P within a range that does not affect performance, so the P content is controlled below 0.015%.

[0022] S:≤0.005%

[0023] S is also a harmful element in steel. It easily forms MnS in steel, which can easily become the source of crack formation in subsequent processing and has a great impact on the toughness of steel. However, considering the operability and cost of steelmaking, S is controlled below 0.005%.

[0024] Cr: 0.40%~0.50%

[0025] Cr, as the main element of this patent, is an element that stabilizes carbides. The addition of chromium reduces the dissolution rate of carbides, improves the toughness and hardenability of steel, and reduces local decarburization caused by the penetration and diffusion of H atoms in the metal lattice. During the tempering process, the Cr-containing carbides generated are dissolved in the matrix and refine the grains, so the Cr content is controlled between 0.40% and 0.50%.

[0026] Mo: 0.05%~0.15%

[0027] Mo, the primary element in this patent, possesses a strong carbon-binding capacity in steel, improving corrosion resistance and reducing defects such as decarburization and hydrogen bulging caused by hydrogen in steel plates. Mo also promotes bainite transformation, inhibits the formation of grain-boundary ferrite, and provides nucleation sites for acicular ferrite during welding, improving weldability. Through solid solution strengthening, it dissolves in austenite and ferrite to enhance the strength and toughness of the steel while also suppressing temper brittleness. However, a high Mo content increases hardness, affecting subsequent processing performance, so the content is controlled between 0.05% and 0.15%.

[0028] Ni: 0.20%~0.40%

[0029] Nickel is a key element in steel that stabilizes austenite. It can exist in a solid solution with Fe in austenite and ferrite, thereby increasing steel strength, refining grain size, and improving low-temperature impact toughness. However, due to its high cost and the difficulty it makes removing oxide scale from steel, which increases costs, the nickel content is limited to 0.20% to 0.40%.

[0030] V: 0.20%~0.40%

[0031] V dissolves into austenite at high temperatures and, after solid solution, increases the hardenability of the steel. V primarily exists in steel as precipitates, ensuring its strength and hardness through precipitation strengthening. Microalloying increases the formation of V-containing carbonitrides in the steel. The precipitation of carbonitrides facilitates the formation of intragranular ferrite nucleation coherent interfaces at grain boundaries, inhibiting grain boundary movement and grain growth, and improving the steel's toughness and tempering stability. V can form complex precipitations with inclusions, facilitating deformation-induced ferrite transformations. Adjusting the V to C ratio increases the amount of carbides formed by vanadium and carbon in the steel, improving the steel's resistance to hydrogen corrosion in low-temperature, high-pressure service environments. Therefore, V is limited to 0.20% to 0.40%.

[0032] Nb: 0.02%~0.03%

[0033] Nb in steel can inhibit austenite recrystallization during rolling, promote grain refinement, increase strength and toughness, reduce overheat sensitivity and temper brittleness, and improve weldability. It can also produce solid solution strengthening, precipitating large amounts of Nb (C, N) at grain boundaries and dislocations. Low Nb content can improve the toughness of the heat-affected zone (HAZ) of steel plates. However, high Nb content slows the cooling rate of the HAZ during high-heat-input welding. At high Nb content, Nb segregates at grain boundaries and easily precipitates, creating carbon-depleted zones. This promotes the nucleation and growth of ferrite at austenite grain boundaries at high temperatures. Therefore, the Nb content is limited to 0.02% to 0.03%.

[0034] Ti: 0.02%~0.04%

[0035] Ti is the main element of this patent. As one of the most effective microalloying elements that promotes the formation of beneficial inclusions and acicular ferrite, it can form a large number of dispersed, fine TiN or TiO particles. After Ti treatment during the steelmaking process, when its content is within a reasonable range, it can change the composition, size, and distribution of weld inclusions. They can also serve as heterogeneous nucleation cores for acicular ferrite during structural solidification, promoting the formation of acicular ferrite within the grains during solidification and cooling, thereby refining the grains. When w(Ti) ≥ 0.09%, not only will the acicular ferrite content be reduced, but it will also cause the formation of large amounts of bainite and hard-brittle MA components, deteriorating the low-temperature toughness of the steel plate. Therefore, the Ti content is limited to 0.02% to 0.04%.

[0036] Al: 0.003%~0.005%

[0037] Al serves as the primary deoxidizer in steel, fixing nitrogen, refining grains, and improving steel toughness. During steel plate welding, the nitrides that precipitate at high temperatures refine the weld heat-affected zone (HAZ). To ensure more effective deoxidation and nitrogen fixation, the Al content is limited to 0.003% to 0.005%.

[0038] Ca: 0.003%~0.005%

[0039] Ca acts as a deoxidizer and desulfurizer in steel and can modify inclusions. During the steelmaking process, oxide metallurgical treatment produces beneficial composite inclusions. After heat treatment, these inclusions become spheroidized and small, providing nucleation sites for acicular ferrite. Therefore, the Ca content is limited to 0.003% to 0.005%.

[0040] The second technical solution of the present invention is to provide a method for manufacturing high-strength hydrogen storage container steel plate with excellent resistance to large linear energy, including the following process flow: smelting, continuous casting, slab heating, controlled rolling, cooling, and heat treatment.

[0041] 1. Smelting:

[0042] Specifically, it includes molten iron pretreatment - converter smelting - argon blowing and stirring - LF furnace refining - RH vacuum treatment.

[0043] The molten iron is first pretreated in an argon station, controlled at a temperature between 1350-1450°C. It is then blown in a converter from top to bottom, with Ti iron added for deoxidation. Al wire, Ca wire, and Mg alloy wire are then added at intervals of no more than 6 minutes to deform non-metallic inclusions in the molten steel and leverage the effects of oxide metallurgy. The molten iron is then refined in an LF furnace to adjust its composition, ensuring an argon soft blowing time of 12-18 minutes and a refining time of 30-60 minutes to ensure uniform chemical composition and remove impurities. Deep dephosphorization and desulfurization are then performed to reduce the phosphorus content and sulfur content in the molten steel to below 0.015% and below 0.005%. RH vacuum treatment is then used for further refining and composition adjustment, ensuring a molten steel temperature of 1600-1620°C and a vacuum degree of ≤5.0 mbar for 40-80 minutes to fully float inclusions, ensuring the purity of the molten steel and allowing sufficient time for microalloying. By first adding Ti iron and then adding Al wire-Ca wire-Mg alloy wire, the non-metallic inclusions in the molten steel are deformed, the role of oxide metallurgy is brought into play, the quality of the continuous casting billet is improved, and beneficial composite inclusion particles are obtained, providing a heterogeneous nucleation core for subsequent microstructure formation.

[0044] 2. Casting

[0045] The entire casting process is performed under argon protection. Light reduction technology is used, with the reduction controlled at 2-5mm. The casting speed is controlled at 0.9-1.3m / min to eliminate internal defects and improve the surface quality of the ingot. Beneficial composite inclusion particles provide nucleation sites for the ingot grains, thereby refining the grain size. The secondary cooling water flow is controlled at 5000-6000L / min to improve central segregation and porosity, and enhance the internal quality of the ingot. The casting superheat is kept between 20-40°C to improve the internal quality of the ingot. The ingot straightening temperature is controlled at 960±30°C to reduce the formation of cracks in the ingot. The resulting continuous casting ingot has a thickness of 300-360mm. Finally, the ingot is cleaned, slowly cooled, and the ingot quality is inspected.

[0046] 3. Heating

[0047] Continuous casting slab heating is divided into preheating, heating, and soaking stages: the preheating stage is controlled at 700-800°C, the heating stage at 1250-1300°C, and the soaking stage at 1180-1220°C. The total slab in-furnace time is 210-270 minutes to ensure uniform slab temperature. This three-stage heating process allows the core temperature of the slab to reach 1180-1220°C, ensuring a fully austenitic structure. However, heating temperatures above 1300°C can easily lead to excessive grain growth within the slab, affecting the distribution of beneficial inclusions within the structure.

[0048] 4. Rolling

[0049] After the billet leaves the furnace, a two-stage controlled rolling and cooling technology is employed. First, rough rolling is performed, with the starting rolling temperature controlled between 1130 and 1180°C, the rolling speed between 1.1 and 1.5 m / s, and the single-pass reduction between 12% and 18%, ensuring a total roughing reduction of 55% or more, to fully refine the austenite grains. Finishing rolling begins at a temperature of 900 ± 50°C, with the final rolling temperature between 820 and 840°C, the rolling speed between 1.0 and 1.3 m / s, and the single-pass reduction between 13% and 35% respectively. This further flattens and elongates the grains, increasing the grain boundary area and providing more nucleation sites for the subsequent phase transformation process. By controlling the total reduction between roughing and finishing rolling, the grains of the steel plate are sufficiently refined, eliminating internal defects. After rolling, controlled cooling is performed with an initial cooling temperature of 750-800°C, a return to red heat temperature of 580-650°C, and a cooling rate of 11-24°C / s. This ensures fine grains, promotes the formation of fine precipitates, and improves the mechanical properties of the steel plate. The steel plates are then stacked for slow cooling at a temperature of 400-550°C. The number of stacked plates ranges from 10 to 16, and the stacking time is guaranteed to be 16-24 hours, allowing sufficient time for the elimination of H and O in the steel plates. The resulting steel plates are 36-60mm thick.

[0050] 5. Heat treatment

[0051] After stacking and slow cooling, the steel plates undergo a tempering heat treatment. To ensure the various mechanical properties of the steel plates, the steel plates are first subjected to a tempering heat treatment process with a quenching temperature of 950±10°C, a quenching heating rate of 1.5±0.2min / mm, a tempering temperature of 620±10°C, and a tempering heating rate of 1.4±0.3min / mm. After the tempering heat treatment, the plates are air-cooled. The tempering heat treatment spheroidizes and refines the particles of beneficial composite inclusions, and evenly distributes fine precipitates in the structure, ensuring high strength and good low-temperature performance of the steel plates. The steel plates also have a uniform structure, consisting of tempered bainite (85-95% by volume) and acicular ferrite (5-15% by volume).

[0052] The beneficial effects of the present invention are:

[0053] The present invention, based on the strengthening elements C, Si and Mn, first reduces the C content in the steel to ensure that the carbon equivalent is sufficiently low, thus meeting the excellent welding performance conditions of the steel plate. To ensure sufficient strength and toughness of the steel plate, the Mn content is increased to compensate for the strength loss caused by the reduced C content. The Mn content within a certain range can improve the toughness of the weld metal and the solubility of Nb and V in the steel. Mo, a carbon-fixing element, is added to dissolve it in the matrix, refine the grains, reduce local decarburization caused by the penetration and diffusion of hydrogen atoms in the metal lattice, reduce the generation of steel plate defects caused by hydrogen atoms, and improve the hydrogen resistance of the steel plate. A small amount of Ti is added to form a large number of dispersed fine TiN or TiO particles. After Ti treatment during the steelmaking process, the composition, size and distribution morphology of weld inclusions can be changed, and these inclusions can serve as heterogeneous nucleation cores for acicular ferrite during microstructure solidification.

[0054] During oxygen converter smelting, Ti iron is first added, followed by Al wire, Ca wire, and Mg alloy wire. This deforms non-metallic inclusions in the molten steel, fully utilizing the effects of oxide metallurgy. Combined with vacuum treatment, this process utilizes fully protected pouring during continuous casting to improve the quality of the continuous casting billet. This produces beneficial composite inclusion particles, which serve as heterogeneous nucleation sites for acicular ferrite during solidification. After heat treatment, the composite inclusion particles become spheroidized, providing nucleation sites for acicular ferrite.

[0055] 1. The microstructure of the steel plate of the present invention is bainite tempered structure + acicular ferrite, with the volume of bainite tempered structure accounting for 85-95%, the volume of acicular ferrite accounting for 5-15%, the grain size of 8-10, and the average size of composite inclusions of 1-3 μm.

[0056] 2. The thickness of the steel plate of the present invention is 36-60mm. After the steel plate for container is subjected to the quenching and tempering heat treatment process, the steel plate has high strength performance, good low temperature performance and excellent mechanical properties after simulated post-weld heat treatment. Its mechanical properties are: yield strength R eL ≥600MPa, tensile strength R m :720~850MPa, elongation A≥21%, -50℃ low temperature impact toughness KV2≥100J, -50℃ low temperature tensile yield strength R eL ≥620MPa, tensile strength R m :735~880MPa, elongation A≥21%;

[0057] 3. The present invention adopts a large line energy of 100-150kJ / cm to weld the steel plate, and the yield strength of the heat affected zone (HAZ) R eL ≥650MPa, tensile strength R m:800~920MPa, elongation ≥18%, impact toughness KV2 ≥80J in -50℃ HAZ zone.

[0058] 4. The steel plate of the present invention exhibits excellent resistance to hydrogen-induced cracking after heat treatment. The sample was immersed in solution A (5% by mass NaCl + 0.5% by mass glacial acetic acid solution) with nitrogen gas injection for 60-80 minutes, immersion for 96-98 minutes, and the immersion solution temperature at 25±3°C. The crack length percentage (CLR), crack thickness percentage (CTR), and crack sensitivity percentage (CSR) were ≤5%.

[0059] 5. The present invention simulates the post-weld heat treatment process to test the mechanical properties of the steel plate. The simulated post-weld heat treatment temperature is 580-650℃ and the holding time is 120-360min. The mechanical properties requirements are: yield strength R eL ≥600MPa, tensile strength R m :720~850MPa, elongation A≥21%, -50℃ low temperature impact toughness KV2≥100J. DETAILED DESCRIPTION

[0060] The present invention will be further described below by way of examples.

[0061] The embodiment of the present invention carries out smelting, continuous casting, slab heating, controlled rolling, cooling, and heat treatment according to the component ratio of the technical solution.

[0062] Slab heating

[0063] The preheating section is controlled at 700-800℃, the heating section is controlled at 1250-1300℃, the soaking section is controlled at 1180-1220℃, and the total slab in-furnace time is 210-270min;

[0064] Rolling

[0065] After the billet is unmolded, a two-stage controlled rolling and controlled cooling technology is adopted. The starting temperature of the rough rolling is 1130-1180℃, the rolling speed is controlled at 1.1-1.5m / s, the single-pass reduction rate is controlled at 12%-18%, and the total reduction rate is guaranteed to be ≥58%. The starting temperature of the finishing rolling is 900±50℃, the final rolling temperature is 820-840℃, the rolling speed is controlled at 1.0-1.3m / s, the single-pass reduction rate of the finishing rolling is ≥13%, and the total reduction rate of the finishing rolling pass is guaranteed to be ≥35%.

[0066] cool down

[0067] After rolling, the steel plates are cooled in a controlled manner, with the cooling temperature at 750-800°C, the red-hot temperature at 580-650°C, and the cooling rate at 11-24°C / s. The plates are then stacked and slowly cooled at a temperature of 400-550°C. The number of stacked plates is 10-16, and the stacking time is guaranteed to be 16-24 hours.

[0068] Heat treatment

[0069] The steel plate is first subjected to a quenching and tempering heat treatment process, with a quenching temperature of 950±10℃, a quenching heating rate of 1.5±0.2min / mm, a tempering temperature of 620±10℃, a tempering heating rate of 1.4±0.3min / mm, and air cooling after the quenching and tempering heat treatment.

[0070] Furthermore, the smelting process includes top and bottom blowing in a converter, first adding Ti iron for deoxidation, then adding Al wire, Ca wire, and Mg alloy wire to deform the non-metallic inclusions in the molten steel; using LF furnace refining to adjust the composition, ensuring that the argon soft blowing time is 12-18 minutes and the refining time is 30-60 minutes; then using RH vacuum treatment to further refine and adjust the composition, ensuring that the molten steel temperature is 1600-1620°C, and the vacuum treatment time is 40-80 minutes.

[0071] Furthermore, the pouring process is argon-protected pouring throughout, and the billet is cast using light reduction technology, the reduction amount is controlled at 2-5 mm, the billet drawing speed is controlled at 0.9-1.3 m / min, the secondary cooling water is controlled at 5000-6000 L / min, the casting superheat is 20-40°C, and the billet straightening temperature is controlled at 960±30°C.

[0072] The present invention is described in detail in the following examples. These examples are intended only as a general description of the present invention and are not intended to limit the present invention. Table 1 shows the chemical composition of the examples, Table 2 shows the smelting and casting methods of the examples, Table 3 shows the rolling process parameters of the examples, Table 4 shows the cooling and heat treatment process parameters of the examples, Table 5 shows the mechanical properties of the examples, Table 6 shows the mechanical properties of the weld heat-affected zone of the examples, Table 7 shows the results of the microstructure volume, grain size, and hydrogen-induced cracking resistance tests of the examples, and Table 8 shows the mechanical properties of the steel after post-weld heat treatment of the present invention.

[0073] Table 1 Chemical composition of the examples (wt%)

[0074]

[0075] Table 2 Example smelting and casting method

[0076]

[0077] Table 3 Rolling process parameters of the embodiment

[0078]

[0079]

[0080] Table 4 Cooling and heat treatment process parameters of the embodiment

[0081]

[0082] Table 5 Mechanical properties of the examples

[0083]

[0084] Table 6 Mechanical properties of heat affected zone of welding of example

[0085]

[0086] Table 7 Example tissue volume, grain size and hydrogen-induced cracking resistance test results

[0087]

[0088]

[0089] Note: The sample is immersed in solution A, filled with nitrogen for 60-80 minutes, immersed for 96-98 hours, and the solution temperature is 25±3°C. Solution A is (5% by mass NaCl + 0.5% by mass acetic acid solution).

[0090] Table 8 Mechanical properties of steel after heat treatment in accordance with the present invention

[0091]

[0092] Note: The heat treatment temperature for die welding is 580-650℃ and the holding time is 120-360min.

[0093] Samples of the weld heat-affected zone (HAZ) were tested according to GB / T229-2020, "Metallic Materials Charpy Pendulum Impact Test Method," and the results showed that the -50°C low-temperature impact toughness was above 100J, indicating that the HAZ of the steel plate has good low-temperature impact toughness. Tensile tests were conducted on the steel plate according to GB / T228.3-2019, "Metallic Materials Tensile Test Part 3: Low-Temperature Test Methods." The yield strength and tensile strength were both above 100J, indicating that the steel plate has high strength and is suitable for the low-temperature service environment of hydrogen storage. Grain size was measured according to GB / T6394-2017, "Method for Determination of Average Grain Size of Metals," and the grain size of the steel plate was above grade 8, indicating that the steel plate has low crack sensitivity. The HIC resistance of the steel plate was tested according to GB / T 8650-2015, "Evaluation Method for Resistance to Hydrogen-Induced Cracking of Pipeline Steels and Pressure Vessel Steels," and the results showed that the designed steel grade has good HIC resistance. These fully demonstrate that the steel plate has excellent resistance to high line energy welding and hydrogen resistance.

[0094] As can be seen from the above, the steel plate of the present invention has high strength performance, good low temperature impact toughness at -50℃ and excellent mechanical properties after simulated post-weld heat treatment. The mechanical properties of the steel plate and the mechanical properties after simulated post-weld heat treatment are as follows: yield strength R eL ≥600MPa, tensile strength R m : 720~850MPa, elongation ≥21%, -50℃ low temperature impact toughness KV2 ≥100J, -50℃ low temperature tensile yield strength R eL ≥620MPa, tensile strength R m :735~880MPa, elongation ≥21%; use high wire energy 100~150kJ / cm to weld steel plates, the yield strength of the heat affected zone (HAZ) R eL ≥650MPa, tensile strength R m : 780~900MPa, elongation ≥18%, -50℃ HAZ zone impact toughness KV2 ≥80J, steel plate thickness specification 36~60mm; and has good resistance to hydrogen-induced cracking.

[0095] In order to describe the present invention, the present invention has been appropriately and fully illustrated through the examples above. The above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made should be included in the scope of protection of the present invention, and the patent protection scope of the present invention should be defined by the claims.

Claims

1. A method for producing a high-strength steel plate for a hydrogen storage container having excellent resistance to high linear energy, comprising smelting, continuous casting, slab heating, controlled rolling, cooling, and heat treatment, characterized in that: Slab heating The preheating section is controlled at 700-800℃, the heating section is controlled at 1250-1300℃, the soaking section is controlled at 1180-1220℃, and the total slab in-furnace time is 210-270min; Rolling After the billet is unmolded, a two-stage controlled rolling and controlled cooling technology is adopted. The starting temperature of the rough rolling is 1130~1180℃, the rolling speed is controlled at 1.1~1.5m / s, the single-pass reduction rate is controlled at 12%~18%, and the total reduction rate is guaranteed to be ≥58%; the starting temperature of the finishing rolling is 900±50℃, the final rolling temperature is 820~840℃, the rolling speed is controlled at 1.0~1.3m / s, the single-pass reduction rate of the finishing rolling is ≥13%, and the total reduction rate of the finishing rolling pass is guaranteed to be ≥35%; cool down After rolling, the steel plates are subjected to weak cooling, with the initial cooling temperature at 750-800°C, the red-returning temperature at 580-650°C, and the cooling rate at 11-24°C / s; then they are stacked and slowly cooled, with the slow cooling temperature at 400-550°C. The number of steel plates stacked is 10-16, and the stacking time is guaranteed to be 16-24 hours; Heat treatment The steel plate is first subjected to a quenching and tempering heat treatment process, with a quenching temperature of 950±10℃, a quenching heating rate of 1.5±0.2min / mm, a tempering temperature of 620±10℃, a tempering heating rate of 1.4±0.3min / mm, and air cooling after the quenching and tempering heat treatment; A high-strength hydrogen storage container steel plate with excellent resistance to large linear energy comprises the following components, measured by weight: C: 0.08%-0.10%, Si: 0.20%-0.35%, Mn: 1.60%-1.80%, P: ≤0.015%, S: ≤0.005%, Cr: 0.40%-0.50%, Mo: 0.05%-0.15%, Ni: 0.20%-0.40%, V: 0.20%-0.25%, Nb: 0.02%-0.03%, Ti: 0.02%-0.04%, Al: 0.003%-0.005%, Ca: 0.003%-0.005%, and the balance being Fe and unavoidable impurities.

2. The method for manufacturing a high-strength steel plate for a hydrogen storage container having excellent resistance to large heat input according to claim 1, characterized in that: The component V / C is ≥2.

3. The method for manufacturing a high-strength steel plate for a hydrogen storage container having excellent resistance to large heat input according to claim 1, characterized in that: The steel plate has a yield strength ReL ≥ 600 MPa, a tensile strength Rm: 720~850 MPa, an elongation ≥ 21%, an impact toughness KV2 ≥ 100 J at -50°C, a low-temperature tensile yield strength ReL ≥ 620 MPa at -50°C, a tensile strength Rm: 735~880 MPa, and an elongation ≥ 21%.

4. The method for manufacturing a high-strength steel plate for a hydrogen storage container having excellent resistance to large heat input according to claim 1, wherein: The steel plates are welded with a high wire energy of 100~150kJ / cm, the HAZ yield strength ReL of the welding heat affected zone is ≥650MPa, the tensile strength Rm is 780~900MPa, the elongation is ≥18%, and the HAZ impact toughness KV2 of the -50℃ welding heat affected zone is ≥80J.

5. The method for manufacturing a high-strength steel plate for a hydrogen storage container having excellent resistance to large heat input according to claim 1, wherein: The steel plate microstructure is bainite tempered structure + acicular ferrite, wherein the bainite tempered structure accounts for 85-95% of the volume, the acicular ferrite accounts for 5-15% of the volume, the grain size is 8-10, and the average size of the composite inclusions is 1-3 μm.

6. The method for manufacturing a high-strength steel plate for a hydrogen storage container having excellent resistance to high heat input according to claim 1, wherein: The steel plate has a thickness of 36-60 mm.

7. The method for manufacturing a high-strength steel plate for a hydrogen storage container having excellent resistance to large heat input according to claim 1, wherein: The smelting process includes top and bottom blowing in a converter, first adding Ti iron for deoxidation, then adding Al wire, Ca wire, and Mg alloy wire, ensuring that the argon soft blowing time is 12-18 minutes; using an LF furnace for refining and adjusting the composition, and the refining time is 30-60 minutes; then using RH vacuum treatment and further refining and adjusting the composition, ensuring that the molten steel temperature is 1600-1620°C, and the vacuum treatment time is 40-80 minutes.

8. The method for manufacturing a high-strength steel plate for a hydrogen storage container having excellent resistance to large heat input according to claim 1, characterized in that: The continuous casting process is argon-protected pouring throughout, and the billet is cast using a light reduction technology, with the reduction amount controlled at 2-5 mm, the billet drawing speed controlled at 0.9-1.3 m / min, the secondary cooling water controlled at 5000-6000 L / min, the casting superheat at 20-40°C, and the billet straightening temperature controlled at 960±30°C.

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