Pressure vessel steel plate for hydrogen storage tank with low crack induction sensitivity and manufacturing method thereof

Abstract

The invention relates to a pressure vessel steel plate for a hydrogen storage tank body with low crack induction sensitivity and a manufacturing method thereof. The chemical components of the steel are as follows, calculated by weight percentage: C 0.80%-0.90%, Si 0.15%-0.40%, Mn 1.00%-1.60%, P≤0.012%, S≤0.005%, Cr 0.9%-1.8%, Ni 0.50%-1.35%, Mo 0.2%-0.8%, Nb 0.03%-0.06%, Ti 0.02%-0.03%, Cu 0.15%-0.25%, V 0.02%-0.06%, B 0.001%-0.002%, and the remainder is Fe and unavoidable impurities. This invention utilizes a network carbide control process involving chromium microalloying, continuous casting, electroslag remelting, controlled rolling and cooling, and spheroidizing to refine the microstructure. This results in high-carbon steel with not only high room-temperature strength but also excellent low-temperature ductility and toughness. This treatment results in a perfectly spheroidized microstructure with a cementite grain size of 0.5 to 1.0 μm and a network carbide grade of 2-3. This effective control of the network carbide grade significantly reduces the product's crack-inducing susceptibility and improves fatigue life.

Description

Technical Field

[0001] The present invention belongs to the technical field of steel, and in particular relates to a pressure vessel steel plate for a hydrogen storage tank body with low crack induction sensitivity and a manufacturing method thereof. Background Art

[0002] Traditionally, high-carbon steel has high hardness and strength, making it suitable for the production of tool steel and die steel where toughness requirements are low. However, due to its high crack-inducing sensitivity and short fatigue life, it cannot be used in the production of equipment such as pressure vessels that serve for long periods in complex environments. With the continuous development of the industry, equipment is trending towards larger sizes, higher performance, reduced weight, and longer service lives. This places higher demands on the raw materials used in equipment manufacturing. The strength and toughness of traditional low-carbon alloy container steel plates can no longer meet the manufacturing requirements of high-end pressure vessel equipment. It is well known that the performance of a material depends on its microstructure. For high-carbon hypereutectoid steel, reducing the proportion of network carbides in the microstructure and refining the grade of carbides so that they are evenly distributed in the microstructure will greatly improve the material's comprehensive mechanical properties and achieve a high degree of matching strength and toughness. Currently, microstructure refinement has been successfully achieved in low-carbon steel, but microstructure refinement in medium- and high-carbon steels is relatively understudied.

[0003] At present, the relevant existing public technologies in China are:

[0004] 1) CN201710037112.8 discloses a manufacturing process for large-scale 42CrMo4 quenched and tempered steel for the outer spindle of a wind turbine speed increaser. The chemical composition of this invention is carbon: 0.38-0.45, silicon: no more than 0.04, manganese: 0.60-0.80, chromium: 0.90-1.20, molybdenum: 0.15-0.30, phosphorus: no more than 0.025, sulfur: no more than 0.035, oxygen: no more than 0.0025, and hydrogen: no more than 0.0002. This composition system is fundamentally different from that of the present invention. Furthermore, this invention uses a die casting + 3500t high-speed forging machine forging process, which results in high production costs, high energy consumption, slow production pace, and poor product shape and performance uniformity.

[0005] 2) CN201710919045.2 discloses a normalizing method for achieving microstructure refinement of low-activation pearlite / martensite steel, characterized by heating to 900-930°C at 50-60°C / s, holding for 1-2 seconds, and then air-cooling to room temperature (20-25°C) to refine the duplex stainless steel structure. This invention differs from the present invention in chemical composition and steel plate type. Furthermore, this invention only provides a heat treatment process, without specifying the characteristics of the rolling process or the degree and level of microstructure refinement. Summary of the Invention

[0006] The purpose of the present invention is to provide a pressure vessel steel plate for a hydrogen storage tank body with low crack induction sensitivity and a method for manufacturing the same. The present invention adopts chromium microalloying + continuous casting billet smelting + electroslag remelting + controlled rolling and controlled cooling + spheroidizing treatment and other network carbide control technologies to achieve microstructure refinement, so that the high carbon steel not only has high room temperature strength, but also has good low temperature plasticity and toughness. After the above treatment, a perfectly spherical microstructure can be obtained, the grain size of the cementite reaches 0.5 to 1.0 μm, and the network carbide grade is 2-3. Effective control of the network carbide grade greatly reduces the crack induction sensitivity of the product and improves fatigue life. The good service performance and mechanical properties of high carbon steel make it expected to be widely used in the field of pressure vessel equipment manufacturing.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The chemical composition of the pressure vessel steel plate for hydrogen storage tank body with low crack induction sensitivity is calculated as follows by weight: C 0.80% to 0.90%, Si 0.15% to 0.40%, Mn 1.00% to 1.60%, P≤0.012%, S≤0.005%, Cr 0.9% to 1.8%, Ni 0.50% to 1.35%, Mo 0.2% to 0.8%, Nb 0.03% to 0.06%, Ti 0.02% to 0.03%, Cu 0.15% to 0.25%, V 0.02% to 0.06%, B 0.001% to 0.002%, and the rest is Fe and unavoidable impurities.

[0009] The reasons for adopting the above components are as follows:

[0010] 1) C: C is a primary element in steel, and its strength is primarily determined by its C content. Excessively high C content results in poor toughness, ductility, and weldability; low C content leads to lower strength and post-stress relief properties. To ensure that the steel plate maintains a good balance between low-temperature impact toughness, strength, and weldability during use, the present invention requires that the C content in the steel be controlled within the range of 0.80% to 0.90%.

[0011] 2) Si: The addition of Si to medium carbon steel affects the thermodynamics of the iron-carbon system and the kinetics of carbide formation and dissolution. As a pearlite-stabilizing element, silicon increases the Ac1 point of the steel. The addition of silicon reduces the carbon content of the eutectoid components, thereby increasing the number of pro-eutectoid carbides and increasing the volume fraction of carbides used to pin grain boundaries in the γ+θ two-phase region. This not only inhibits the growth of pearlite and austenite grains, but also prevents the growth of carbides. Silicon is insoluble in carbides. When carbides precipitate, silicon is distributed around the carbides, forming localized high-concentration areas of silicon. Silicon is also an element that increases carbon activity. In high-concentration areas of silicon, the activity of carbon is also increased, which reduces the diffusion rate of carbon into the carbides, thereby inhibiting the coarsening of carbides. Therefore, the Si content of the present invention is controlled to 0.15% to 0.40%.

[0012] 3) Mn: The Mn element can strengthen pearlite in steel by solid solution strengthening. C-Mn strengthening is also the main way to improve the strength of low carbon steel. However, if the Mn content is too high, it will increase the production cost. At the same time, the Mn element is easy to combine with the S element to form MnS, which reduces the material's resistance to hydrogen-induced cracking. At the same time, too high a Mn content will reduce the activity of the carbon element. Therefore, the Mn content in the steel is required to be controlled at 1.00% to 1.60%.

[0013] 4) Phosphorus: Phosphorus is a harmful element in steel. It increases cold brittleness, deteriorates weldability, reduces plasticity, and worsens cold bending properties. Phosphorus is also particularly sensitive to radiation embrittlement. Therefore, the lower the phosphorus content in steel, the better. The present invention requires a phosphorus content of less than 0.012%.

[0014] 5) Sulfur: Sulfur is generally a harmful element. Sulfur readily forms brittle sulfides with alloying elements in steel, causing hot brittleness and reducing ductility and toughness. It also tends to accelerate radiation embrittlement. Therefore, the present invention requires that the sulfur content in steel be limited to less than 0.005%.

[0015] 6) B: B can lower the transformation temperature from austenite to pearlite, promote the formation of acicular pearlite within the grains, and refine the grains. Therefore, the present invention requires that the B content in the steel be controlled to 0.001% to 0.002%.

[0016] 7) V: V is a microalloying element. Microalloying of V in steel can form fine second-phase particles, which play a role in pinning grain boundaries and precipitation strengthening. It can effectively refine the grains and greatly improve the comprehensive mechanical properties of steel such as strength, toughness, ductility and thermal fatigue resistance. Therefore, the range of V added to steel is 0.02% to 0.06%.

[0017] 8) Ni: Ni is a solid solution strengthening element in steel that can improve the strength of steel. Ni reduces the resistance to dislocation movement in steel, relaxes stress, and then changes the substructure of the matrix organization, thereby improving the toughness of steel, especially low-temperature toughness. However, excessive Ni content in medium carbon steel will increase the phase transition temperature, so the Ni content is controlled at 0.50% to 1.35%.

[0018] 9) Cr: Chromium is a carbide-stabilizing element. Adding chromium reduces the dissolution rate of carbides. Therefore, when employing a hot deformation microstructure refinement process, even when the heating temperature or time is increased, eutectoid transformation can be avoided, resulting in a refined microstructure. Chromium also inhibits graphitization in ultra-high carbon steel containing silicon and aluminum, increases the steel's hardenability, and provides secondary hardening. This improves the hardness and wear resistance of high-carbon steel without brittleness, thereby increasing fatigue life. Therefore, the present invention requires that the Cr content in the steel be controlled to 0.9% to 1.8%.

[0019] 10) Cu: Cu's prominent role in steel is improving the corrosion resistance of plain carbon low-alloy steel, while also increasing its strength and yield strength ratio without adversely affecting weldability. When the copper content exceeds 0.75%, it can produce an age-hardening effect after solution treatment and aging. Its effects are similar to those of nickel, contributing to nickel conservation and cost reduction. However, higher content can lead to copper embrittlement during hot deformation. Therefore, the present invention requires that the Cu content in steel be controlled to 0.15% to 0.25%.

[0020] 11) Nb: As a strong carbide-forming element, Nb forms a highly dispersed NbC phase in steel with excellent high-temperature stability, acting as a precipitation strengthening agent. Multi-stage rolling effectively refines grains and improves the toughness loss caused by precipitation strengthening, resulting in a steel plate with both high strength and high toughness. Furthermore, in steels containing a Nb-Mo composite addition, Mo can segregate at the NbC matrix interface, preventing the coarsening of NbC particles and significantly improving the steel's high-temperature strength. Therefore, the Nb content is controlled within a range of 0.03% to 0.06%.

[0021] 12) Mo: Mo mainly relies on solid solution strengthening and grain boundary strengthening to improve the strength of steel. Secondly, Mo increases the stability of supercooled austenite, causing the austenite to pearlite transformation curve to shift to the right, and obtaining a finer pearlite structure after the phase transformation. In addition, Ti and Mo combine to precipitate a large amount of nano-sized Ti-Mo (CN) carbides in the steel. The refined carbides pin dislocations, greatly improving the toughness of the steel. Therefore, the present invention requires that the Mo content in the steel be controlled at 0.2% to 0.8%.

[0022] 13) Ti: Adding an appropriate amount of Ti forms a large number of dispersed, fine TiN or Ti2O3 particles, which serve as heterogeneous nucleation sites for acicular pearlite during solidification, thereby refining the structure. Ti also acts as a deoxidizer, protecting B from oxidation and nitridation. B, in turn, lowers the austenite-to-pearlite transition temperature, promoting the formation of acicular pearlite within the grains and thus refining the grains. However, when w(Ti) ≥ 0.09%, the acicular pearlite content is reduced, deteriorating the low-temperature toughness of the steel plate. Therefore, the present invention requires that the Ti content in the steel be controlled to 0.02% to 0.03%.

[0023] The tensile strength of the steel plate is 1300~1430MPa, the yield strength is 1190~1320MPa, the elongation after fracture is 30%~40%, the cross-sectional shrinkage is 30%~40%, the impact energy at -40℃ is 160~260J, and the lateral expansion value LE is 0.76~0.98mm; the impact energy of the heat affected zone at -40℃ after welding is 110~210J.

[0024] The thickness of the steel plate is 10 to 80 mm.

[0025] The steel plate has a perfectly globalized microstructure, the grain size of cementite reaches 0.5-1.0 μm, and the network carbide grade is 2-3.

[0026] The method for manufacturing a pressure vessel steel plate for a hydrogen storage tank body with low crack induction sensitivity mainly includes continuous casting billet smelting, electroslag remelting, controlled rolling and controlled cooling, and spheroidizing treatment processes; specifically, the method and steps include the following:

[0027] 1) Continuous casting billet smelting: The first stage is the smelting of 250 and 300mm cross-section continuous casting billets. The oxygen-aluminum control method is used to fully improve the purity of the steel, reduce the inclusion content in the steel, control the component segregation, and lay the foundation for reducing the level of network carbides. The specific process parameters are: in the converter smelting, the furnace charge block size is controlled at 50-100mm, the oxygen blowing time is shortened to 10-16min, the furnace charge hot charging temperature is controlled at 1150-1200℃, the net heat preservation is 3-6min, the smelting time is shortened to 20-25min, and the oxygen supply intensity is reduced, that is, the oxygen consumption per ton of steel is controlled within the range of 40-55Nm 3 / t; A two-step aluminum deoxidation process is also employed: a composite deoxidation system involving pre-deoxidation with aluminum cake during the converter tapping process and final deoxidation with aluminum wire during the LF furnace refining process. Reducing Ds inclusions requires carefully controlling the amount of Al deoxidizer added. Ultimately, the Ds inclusion level in the continuous casting billet is controlled between 0.5 and 1.0, completely eliminating Ds inclusions above level 1.5.

[0028] 2) Electroslag Remelting: The second stage involves the smelting of electroslag billets with cross-sections of 330-800mm. During the electroslag remelting process, electroslag water cooling enhancement technology is employed to increase cooling intensity, improve the density of the electroslag ingot's macrostructure, reduce crack defects and component segregation, and lay the foundation for further reducing the level of network carbides. By adding a variable-frequency fan for external circulating water temperature regulation, the inlet temperature of the cooling water is controlled. The crystallizer inlet temperature is maintained at 15-35°C, and the outlet temperature is controlled at 20-40°C. The carbide level of the electroslag billet is controlled at levels 0-1.

[0029] 3) Controlled rolling and controlled cooling: The electroslag billet is slowly cooled for 48 hours, cut, ground, sprayed and then heated again, and rolled in a double-stand rolling mill. First, the continuous casting billet is rough rolled. The rough rolling start temperature is 1100-1130℃, and the rough rolling finish temperature is 910-940℃. The reduction rate of each pass is 15%-25%. The thickness of the intermediate billet is 2-3 times the thickness of the finished steel plate. Rough rolling causes the proeutectoid cementite to form in the form of fine particles at the austenite grain boundaries and high-density dislocation areas within the grains. After rough rolling, the intermediate billet roller swings back and forth to After cooling to 800-850℃, continuous multi-pass finishing rolling is carried out, ensuring a reduction rate of 5%-15% in each pass, until the final thickness of the finished product is reached. The finishing rolling temperature is 750-800℃. The thermal deformation in this process helps to break the pro-eutectoid cementite precipitated from the austenite and avoid the formation of network carbides. Subsequently, ACC laminar cooling is carried out with a cooling start temperature of 700-750℃ and a cooling rate of 40-60℃ / s until it is cooled to room temperature. While refining the grains, it effectively controls the precipitation of network carbides and improves the fatigue life of the product.

[0030] 4) Spheroidizing Heat Treatment: The fourth stage is spheroidizing heat treatment, held at 700-750°C for 20-40 minutes. After power is turned off, the steel is cooled to 600-650°C with the furnace, and then air-cooled to room temperature at a rate of 20-40°C / s. The spheroidizing process effectively controls the precipitation of network carbides. This treatment results in a perfectly spheroidized microstructure with a cementite grain size of 0.5-1.0 μm, a network carbide grade of 2-3, and excellent strength-toughness matching.

[0031] The present invention utilizes network carbide control technology to achieve full carbide refinement, resulting in high-carbon steel with not only high room-temperature strength but also good low-temperature toughness. Low-temperature rolling combined with controlled cooling also allows for a higher elongation after fracture. High-carbon steel's excellent processing and mechanical properties make it promising for widespread application in the manufacture of pressure vessel equipment. This invention describes a low-crack-inducing-susceptibility pressure vessel steel plate for hydrogen storage tanks and its manufacturing method, from the perspectives of smelting, rolling, heat treatment, and chemical alloying.

[0032] The present invention utilizes continuous casting ingot smelting + electroslag remelting + controlled rolling and controlled cooling + spheroidizing treatment. The process can be divided into four stages: the first stage is to fully improve the purity of the steel by using the oxygen-aluminum control method during the continuous casting process. The second stage, during the electroslag remelting process, uses electroslag water cooling to strengthen and improve the cooling intensity, improve the density of the electroslag ingot's macrostructure, reduce crack defects and component segregation, and lay the foundation for reducing the level of network carbides. Subsequently, the third stage of rough rolling is carried out to form proeutectoid cementite in the form of fine particles at the austenite grain boundaries and high-density dislocation areas within the grains. After rough rolling, the rollers are heated to 800-850°C for continuous multi-pass finishing rolling. The thermal deformation in this process helps to break up the proeutectoid cementite precipitated from the austenite and prevent the formation of network carbides. The fourth stage is ACC laminar cooling, with a cooling rate of 40-60°C / s and water cooling to room temperature. While refining the grains, it effectively controls the precipitation of network carbides and improves the fatigue life of the product. The fifth stage is spheroidizing heat treatment, held at 700-750°C for 20-40 minutes. The steel is then cooled to 600-650°C and air-cooled to room temperature at a rate of 20-40°C / s to effectively control the precipitation of network carbides. This treatment results in a perfectly spheroidized microstructure, with cementite grains reaching 0.5-1.0μm and network carbides of grade 2-3.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention provides a low crack induction sensitivity pressure vessel steel plate and a manufacturing method thereof. The specifications of the continuous casting billets are 250 and 300 mm, the specifications of the electroslag billets are 330-800 mm, and the thickness of the produced steel plates is 10-80 mm. Compared with the existing technology, the beneficial effects are as follows:

[0035] Chromium microalloying improves the hardness and wear resistance of high carbon steel without making the steel brittle, greatly reduces the crack-induced sensitivity of the product, and improves fatigue life; the continuous casting billet smelting process adopts the oxygen-aluminum control method to fully improve the purity of the steel, reduce the inclusion content in the steel, and control the composition segregation; in the electroslag remelting process, the electroslag water cooling strengthening improvement technology is adopted to increase the cooling intensity, improve the density of the electroslag ingot macrostructure, reduce crack defects and composition segregation, and further reduce the grade of network carbides; the controlled rolling and controlled cooling process is adopted to effectively control the precipitation of network carbides and crush the precipitated carbides; finally, a completely globalized microstructure is obtained through spheroidizing heat treatment, the grain size of the cementite reaches 0.5~1.0μm, and the network carbide grade is 2-3. The final finished steel plate has a tensile strength of 1300-1430 MPa, a yield strength of 1190-1320 MPa, an elongation after fracture of 30-40%, a cross-sectional shrinkage of 30-40%, an impact energy of -40°C of 160-260 J (and a lateral expansion value LE of 0.76-0.98 mm); and an impact energy of the heat-affected zone after welding of -40°C of 110-210 J. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a metallographic photograph of the steel plate of Example 1 at 500X. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the specific implementation methods of the present invention are further described below in conjunction with examples. The following examples are used to specifically illustrate the contents of the present invention. These examples are only general descriptions of the contents of the present invention and do not limit the contents of the present invention.

[0038] The composition of the steel plates of the present invention is shown in Table 1. The main process parameters for continuous casting slab smelting and electroslag remelting are shown in Table 2. The main process parameters for controlled rolling and controlled cooling are shown in Table 3. The main process parameters for spheroidizing heat treatment of the steel plates of the present invention are shown in Table 4. The grain size and comprehensive mechanical properties of the steel plates of the present invention are shown in Table 5.

[0039] Table 1 Composition of steel plates according to the present invention (wt%)

[0040]

[0041]

[0042] Table 2 Main process parameters of continuous casting slab smelting and electroslag remelting according to the embodiment of the present invention

[0043]

[0044] Table 3 Main process parameters of controlled rolling and controlled cooling of steel plates according to the embodiment of the present invention

[0045]

[0046] Table 4 Main process parameters of spheroidizing heat treatment of steel according to the embodiment of the present invention

[0047]

[0048] Table 5 Grain size and comprehensive mechanical properties of steel plates according to the present invention

[0049]

[0050] 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. Low crack induction sensitivity pressure vessel steel plate for hydrogen storage tank, characterized in that: The chemical composition of the steel is calculated by weight as follows: C 0.80%~0.90%, Si 0.15%~0.40%, Mn 1.00%~1.60%, P≤0.012%, S≤0.005%, Cr 0.9%~1.8%, Ni 0.50%~1.35%, Mo 0.2%~0.8%, Nb 0.03%~0.06%, Ti 0.02%~0.03%, Cu 0.15%~0.25%, V 0.02%~0.06%, B 0.001%~0.002%, and the rest is Fe and unavoidable impurities; The method for manufacturing the pressure vessel steel plate for the hydrogen storage tank body with low crack induction sensitivity specifically comprises the following steps: 1) Continuous casting billet smelting: In converter smelting, the charge size is controlled at 50-100mm, the oxygen blowing time is shortened to 10-16min, the charge hot charging temperature is controlled at 1150-1200℃, the net heat preservation is 3-6min, the smelting time is shortened to 20-25min, and the oxygen consumption per ton of steel is controlled within the range of 40-55Nm 3 / t; 2) Electroslag remelting: The water inlet temperature of the crystallizer is controlled at 15-35°C, the water outlet temperature is controlled at 20-40°C, and the carbide level of the electroslag billet is controlled at level 0-1; 3) Controlled rolling and controlled cooling: The starting temperature of rough rolling is 1100-1130℃, the finishing temperature of rough rolling is 910-940℃, and the reduction rate of each pass is guaranteed to be 15%-25%. After rough rolling, the intermediate billet roller table swings back and forth and air cools until the temperature reaches 800-850℃, and then continuous multi-pass finishing rolling is carried out, ensuring a reduction rate of 5%-15% per pass to the final product thickness. The finishing rolling temperature is 750-800℃; followed by laminar cooling, the starting cooling temperature is 700-750℃, and the cooling rate is 40-60℃ / s, and then water-cooled to room temperature; 4) Spheroidizing heat treatment: the temperature is 700-750℃, the net heat preservation is 20-40min, after the power is turned off, it is cooled to 600-650℃ with the furnace, and then air-cooled to room temperature after being taken out of the furnace. The air cooling rate is 20-40℃ / s.

2. The pressure vessel steel plate for a hydrogen storage tank body with low crack induction sensitivity according to claim 1, characterized in that: The tensile strength of the steel plate is 1300~1430MPa, the yield strength is 1190~1320MPa, the elongation after fracture is 30%~40%, the cross-sectional shrinkage is 30%~40%, the impact energy at -40℃ is 160~260J, and the lateral expansion value LE is 0.76~0.98mm; the impact energy of the heat affected zone at -40℃ after welding is 110~210J.

3. The pressure vessel steel plate for a hydrogen storage tank body with low crack induction sensitivity according to claim 1, characterized in that: The thickness of the steel plate is 10 to 80 mm.

4. The pressure vessel steel plate for a hydrogen storage tank body with low crack induction sensitivity according to claim 1, characterized in that: The steel plate has a perfectly globalized microstructure, the grain size of cementite reaches 0.5-1.0 μm, and the network carbide grade is 2-3.

5. The method for manufacturing a pressure vessel steel plate for a hydrogen storage tank body with low crack induction sensitivity according to any one of claims 1 to 4, characterized in that: The specific method steps include: 1) Continuous casting billet smelting: In converter smelting, the charge size is controlled at 50-100mm, the oxygen blowing time is shortened to 10-16min, the charge hot charging temperature is controlled at 1150-1200℃, the net heat preservation is 3-6min, the smelting time is shortened to 20-25min, and the oxygen consumption per ton of steel is controlled within the range of 40-55Nm 3 / t; 2) Electroslag remelting: The water inlet temperature of the crystallizer is controlled at 15-35°C, the water outlet temperature is controlled at 20-40°C, and the carbide level of the electroslag billet is controlled at level 0-1; 3) Controlled rolling and controlled cooling: The starting temperature of rough rolling is 1100-1130℃, the finishing temperature of rough rolling is 910-940℃, and the reduction rate of each pass is guaranteed to be 15%-25%. After rough rolling, the intermediate billet roller table swings back and forth and air cools until the temperature reaches 800-850℃, and then continuous multi-pass finishing rolling is carried out, ensuring a reduction rate of 5%-15% per pass to the final product thickness. The finishing rolling temperature is 750-800℃; followed by laminar cooling, the starting cooling temperature is 700-750℃, and the cooling rate is 40-60℃ / s, and then water-cooled to room temperature; 4) Spheroidizing heat treatment: the temperature is 700-750℃, the net heat preservation is 20-40min, after the power is turned off, it is cooled to 600-650℃ with the furnace, and then air-cooled to room temperature after being taken out of the furnace. The air cooling rate is 20-40℃ / s.

6. The method for manufacturing a pressure vessel steel plate for a hydrogen storage tank body with low crack induction sensitivity according to claim 5, characterized in that: The step 1) is used to smelt continuous casting billets with cross sections of 250 mm and 300 mm.

7. The method for manufacturing a pressure vessel steel plate for a hydrogen storage tank body with low crack induction sensitivity according to claim 5, wherein: The step 2) is used for smelting electroslag billets with a cross-section of 330 to 800 mm.

8. The method for manufacturing a pressure vessel steel plate for a hydrogen storage tank body with low crack induction sensitivity according to claim 5, wherein: The intermediate billet in step 3) is 2 to 3 times the thickness of the finished steel plate.

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