High-strength easily-welded steel plate for rare earth Q550CFE compressed air energy storage

Abstract

The invention discloses a rare earth Q550CFE high-strength easily-welded steel plate for compressed air energy storage. The rare earth Q550CFE high-strength easily-welded steel plate comprises the following chemical components in percentage by weight: 0.05 to 0.08 percent of C, 0.15 to 0.30 percent of Si, 1.30 to 1.55 percent of Mn, less than or equal to 0.012 percent of P, less than or equal to 0.004 percent of S, 0.015 to 0.030 percent of Nb, 0.030 to 0.045 percent of V, 0.010 to 0.020 percent of Ti, 0.1 to 0.25 percent of Cr, 0.15 to 0.30 percent of Ni, 0.15 to 0.30 percent of Mo, 0.0010 to 0.0020 percent of B, 0.0010 to 0.0020 percent of Ce and the balance of iron and impurities. According to the steel plate, the yield strength is larger than or equal to 550 MPa, the tensile strength is 670-830 MPa, the percentage elongation after fracture is larger than or equal to 16%, and the longitudinal impact energy at the temperature of-40 DEG C is larger than or equal to 200 J.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high-strength steel plate manufacturing, and particularly relates to a rare earth Q550CFE high-strength easy-to-weld steel plate for compressed air energy storage. BACKGROUND

[0002] Compressed air energy storage power station is a kind of energy storage facility that realizes the storage and release of electric energy by using the principle of air compression and expansion. When the power grid load is low, the excess electric energy is used to drive the compressor to compress and store air in the air storage tank (such as underground salt cavern, rock cave, etc.), and the electric energy is converted into the internal energy (pressure energy) of air. When the power grid load is high, the high-pressure air is released, heated and used to drive the turbine generator to generate electricity, and the internal energy is converted into electric energy again. The single station capacity can reach hundreds of megawatts to gigawatts, which is suitable for power grid peak regulation. The equipment can be used for more than 20 years, and the charging and discharging times can reach tens of thousands of times. It does not rely on chemical batteries and does not pollute the environment with heavy metals. Only air is discharged during operation. Compared with pumped storage, it has lower requirements for terrain; the long-term operation cost continues to decrease as the technology matures. As an important way of large-scale physical energy storage, compressed air energy storage is playing an increasingly important role in global energy transformation with technological breakthroughs and cost reductions.

[0003] The steel for compressed air energy storage should have the following characteristics. First, high strength: it needs to withstand the pressure of compressed air of tens of megapascals, such as 600 MPa grade steel, to ensure structural safety and prevent deformation and rupture. Second, good low-temperature toughness: it should still have good toughness at -50℃ low temperature environment to avoid material brittle fracture and ensure normal operation of the equipment. Third, strong fatigue resistance: it needs to have high fatigue resistance to face frequent charging and discharging cycles, prolong the service life and reduce maintenance costs. Fourth, good corrosion resistance: it needs to have good corrosion resistance in humid and high-salt environments such as salt caverns and underground chambers to prevent steel corrosion.

[0004] Chinese patent CN102888571A discloses "a 690MPa low welding crack sensitivity steel and its manufacturing method". A low-carbon design is adopted, and a Nb-V-Ti-Cr-Ni-Mo-Al composition system is used, with Pcm≤0.20%. The steel plate with a thickness of 15-30mm is produced by using controlled rolling and controlled cooling + tempering process, with a tensile strength of 690MPa and an impact energy of ≥47J at -20℃, meeting the requirements of large-scale spherical tank steel. The shortcomings are as follows. First, the controlled rolling and controlled cooling + tempering process requires high cooling capacity of the cold zone equipment, and is prone to cause poor plate shape, which is not suitable for all steel plants. Second, it is only used to produce steel plates with a thickness of 15-30mm. Third, the service temperature is -20℃, which cannot meet the lower temperature requirements.

[0005] Chinese patent CN115948699A discloses "a manufacturing method of 800MPa grade high strength steel plate for stress corrosion resistant spherical tank", adopts low carbon (≤0.12%), low manganese, high Cr component design, appropriate Mo element to improve the hardenability of steel, appropriate Ni element to improve low temperature toughness, adopts controlled rolling, quenching and tempering technology, etc., develops a high strength steel for stress corrosion resistant spherical tank, the maximum thickness of the steel plate is 80mm, the yield strength of the steel plate is ≥690MPa, the tensile strength is 780~940MPa, the elongation after fracture is ≥15%, the low temperature impact energy at-40℃ is ≥100J, the low temperature impact energy at-40℃ after postweld heat treatment is ≥80J; according to NACE 0177-2005 standard, the sample is loaded at 80% of the nominal yield strength, the stress corrosion resistance of hydrogen sulfide is not cracked for 720 hours, which meets the construction requirements of stress corrosion resistant large spherical tank. The disadvantage is that Mo and Cu noble metals are added in the composition, which increases the production cost. The tensile strength is 780~940MPa, which is completely different from the present application.

[0006] Chinese patent CN116043130A discloses "an economic 700MPa storage tank steel plate with excellent die welding performance and manufacturing method", adopts medium carbon, Nb-Ti-Cr component system, Ceq≤0.47%, adopts direct quenching + tempering process production, the tensile strength of the steel plate reaches 700MPa, the impact energy at-70℃ is ≥100J, and the steel plate has good die welding performance, which meets the requirements of large spherical tank steel. The disadvantage is that the direct quenching process requires high cooling equipment and capacity, and is prone to poor plate shape and poor performance stability. SUMMARY

[0007] The purpose of the present application is to provide a rare earth Q550CFE high strength easy-to-weld steel plate for compressed air energy storage, which has the performance of yield strength ≥550MPa, tensile strength 670-830MPa, elongation after fracture ≥16%, longitudinal impact energy at-40℃ ≥200J, and has good welding performance, corrosion resistance and fatigue performance. It meets the requirements of compressed air energy storage power station construction.

[0008] To solve the above technical problems, the present application adopts the following technical scheme:

[0009] This invention discloses a high-strength, easily weldable steel plate for compressed air energy storage using rare earth Q550CFE material. The chemical composition of the steel plate, by weight percentage, is: C: 0.05–0.08%, Si: 0.15–0.30%, Mn: 1.30–1.55%, P: ≤0.012%, S: ≤0.004%, Nb: 0.015–0.030%, V: 0.030–0.045%, Ti: 0.010–0.020%, Cr: 0.1–0.25%, Ni: 0.15–0.30%, Mo: 0.15–0.30%, B: 0.0010–0.0020%, rare earth Ce: 0.0010–0.0020%, Pcm ≤0.22%, with the balance being Fe and unavoidable impurities.

[0010] Furthermore, the chemical composition of the steel plate by weight percentage is: C: 0.06%, Si: 0.22%, Mn: 1.47%, P: 0.010%, S: 0.002%, Nb: 0.016%, V: 0.032%, Ti: 0.015%, Cr: 0.17%, Ni: 0.18%, Mo: 0.18%, B: 0.0012%, rare earth Ce: 0.0011%, with the balance being Fe and unavoidable impurities.

[0011] Furthermore, the chemical composition of the steel plate by weight percentage is: C: 0.07%, Si: 0.15%, Mn: 1.42%, P: 0.011%, S: 0.002%, Nb: 0.018%, V: 0.033%, Ti: 0.013%, Cr: 0.16%, Ni: 0.18%, Mo: 0.17%, B: 0.0014%, rare earth Ce: 0.0012%, with the balance being Fe and unavoidable impurities.

[0012] Furthermore, the chemical composition of the steel plate by weight percentage is: C: 0.07%, Si: 0.15%, Mn: 1.43%, P: 0.012%, S: 0.002%, Nb: 0.019%, V: 0.031%, Ti: 0.015%, Cr: 0.17%, Ni: 0.15%, Mo: 0.18%, B: 0.0013%, rare earth Ce: 0.0011%, with the balance being Fe and unavoidable impurities.

[0013] Furthermore, the chemical composition of the steel plate by weight percentage is: C: 0.07%, Si: 0.16%, Mn: 1.40%, P: 0.009%, S: 0.002%, Nb: 0.018%, V: 0.035%, Ti: 0.014%, Cr: 0.16%, Ni: 0.16%, Mo: 0.20%, B: 0.0014%, rare earth Ce: 0.0014%, with the balance being Fe and unavoidable impurities.

[0014] Furthermore, the chemical composition of the steel plate by weight percentage is: C: 0.08%, Si: 0.17%, Mn: 1.42%, P: 0.009%, S: 0.001%, Nb: 0.020%, V: 0.035%, Ti: 0.016%, Cr: 0.17%, Ni: 0.17%, Mo: 0.21%, B: 0.0015%, rare earth Ce: 0.0018%, with the balance being Fe and unavoidable impurities.

[0015] A method for manufacturing a high-strength, easy-to-weld steel plate for rare earth Q550CFE compressed air energy storage, the main steps and process parameters are as follows:

[0016] S1 molten iron pretreatment: After desulfurization and dephosphorization of molten iron by KR stirring method, ensure that S≤0.005% and P≤0.013% in molten iron;

[0017] S2 converter smelting: The converter smelting stage uses desulfurized pretreated molten iron and high-quality scrap steel as raw materials. The added quicklime, dolomite, alloys, deoxidizers, cored wire, and various slag-forming materials must meet national standards. The molten iron temperature is ≥1260℃. High-efficiency top and bottom blowing technologies are used to reduce phosphorus and carbon content, ensuring that the molten steel has P≤0.010% and S≤0.004%.

[0018] S3LF Ladle Refining: The ladle refining stage precisely controls the steel composition, deoxidizes and alloys, and further reduces non-metallic inclusions and harmful impurities in the steel, with S≤0.004%, to obtain clean steel; the amount of quicklime added is ≥5kg / ton of steel, and the slag sample must be dipped during the refining process to ensure rapid formation of white slag and to keep the white slag for a certain period of time;

[0019] S4RH Vacuum Treatment: This treatment mode further reduces the content of hydrogen, oxygen, and nitrogen gases in molten steel, minimizing the adverse effects of harmful gases on the steel quality. To ensure the effective boron content in the steel, ferrotitanium is added first, followed by ferroboronium during RH vacuum treatment. The vacuum time is maintained at more than 20 minutes, the pure degassing time is greater than 15 minutes, and the soft blowing time is greater than 15 minutes.

[0020] S5 slab continuous casting: Employing dynamic light reduction at the end of solidification (8mm reduction), electromagnetic stirring (350A / 5HZ), weak cooling in the secondary cooling section, and straightening technology, the casting speed is controlled at 0.8–1.0 m / min, and the superheat is 20–30℃, reducing defects such as center segregation and central porosity in the continuously cast slab. After the slab is removed from the line, it is slowly cooled for more than 48 hours, ultimately yielding high-quality slabs with a thickness of 250mm or 300mm and center segregation below C3.0.

[0021] S6 heating: The slab is heated in a walking beam furnace. The furnace atmosphere is strictly controlled to ensure the heating temperature and time of the slab. The heating temperature is controlled at 1200℃~1240℃ and the heating time is greater than 230min to ensure the full solid solution of alloying elements and uniform slab temperature.

[0022] S7 Rolling and Cooling: Rolling employs a two-stage controlled rolling process, commonly referred to as the roughing stage and the finishing stage. Roughing is carried out on a 3800mm roughing mill, with an initial rolling temperature of 1160–1200℃, and the relative reduction rate per pass is controlled at least 14% for at least two passes. During finishing, the deformation amount in each pass is strictly controlled, with an initial finishing rolling temperature ≤950℃ and a final rolling temperature of 800–860℃. The rolled steel plate is then cooled under controlled conditions, with a final cooling temperature of 640–670℃.

[0023] S8 Quenching and Tempering Heat Treatment: After shot blasting, the steel plate is quenched. The quenching temperature is 910℃, and the furnace time is 20min + t × 1.4min / mm. The tempering temperature is 620℃~640℃, and the furnace time is 40min + t × 3.2min / mm, where t is the thickness of the steel plate in mm.

[0024] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0025] A high-strength, easily weldable Q550CFE steel plate for compressed air energy storage is produced using a low-carbon Nb-V-Ti-Ni-Cr-Mo-B-RE composition and a specific manufacturing process. It exhibits a yield strength ≥550MPa, tensile strength 670-830MPa, elongation after fracture ≥16%, and longitudinal impact energy ≥200J at -40℃. It also possesses excellent weldability, corrosion resistance, and fatigue resistance, meeting the construction requirements for compressed air energy storage power stations. Attached Figure Description

[0026] The present invention will be further described below with reference to the accompanying drawings.

[0027] Figure 1 This is a metallographic diagram of the steel plate in Embodiment 3 of the present invention.

[0028] Figure 2 The fracture morphology of the steel plate at -40℃ in Embodiment 3 of the present invention is shown. Detailed Implementation

[0029] The present invention will be described in more detail below with reference to examples. These examples are merely descriptions of the best mode of implementation of the invention and do not limit the scope of the invention in any way.

[0030] The chemical composition of the steel plate of the present invention, by weight percentage, is: C: 0.05-0.08%, Si: 0.15-0.30%, Mn: 1.30-1.55%, P: ≤0.012%, S: ≤0.004%, Nb: 0.015-0.030%, V: 0.030-0.045%, Ti: 0.010-0.020%, Cr: 0.1-0.25%, Ni: 0.15-0.30%, Mo: 0.15-0.30%, B: 0.0010-0.0020%, rare earth Ce: 0.0010-0.0020%, Pcm ≤0.22%, with the balance being Fe and unavoidable impurities.

[0031] Furthermore, this invention also provides a method for manufacturing Q550CFE compressed air energy storage steel plates. The main steps and process parameters are as follows:

[0032] S1 molten iron pretreatment: After desulfurization and dephosphorization of molten iron by KR stirring method, ensure that S≤0.005% and P≤0.013% in molten iron;

[0033] S2 converter smelting: The converter smelting stage uses desulfurized pretreated molten iron and high-quality scrap steel as raw materials. The added quicklime, dolomite, alloys, deoxidizers, cored wire, and various slag-forming materials must meet national standards. The molten iron temperature is ≥1260℃. High-efficiency top and bottom blowing technologies are used to reduce phosphorus and carbon content, ensuring that the molten steel has P≤0.010% and S≤0.004%.

[0034] S3LF Ladle Refining: The ladle refining stage precisely controls the steel composition, deoxidizes and alloys, further reducing non-metallic inclusions and harmful impurities in the steel, achieving S≤0.004% and obtaining clean steel. The amount of quicklime added is ≥5kg / ton of steel. During the refining process, a slag sample must be dipped to ensure rapid formation of white slag and to maintain the white slag for a certain period.

[0035] S4RH Vacuum Treatment: This treatment mode further reduces the hydrogen, oxygen, and nitrogen content in molten steel, minimizing the adverse effects of harmful gases on the steel quality. To ensure an effective boron content in the steel, ferrotitanium is added first, followed by ferroboronium during RH vacuum treatment. The vacuum time is maintained at over 20 minutes, the pure degassing time is greater than 15 minutes, and the soft blowing time is greater than 15 minutes. The final molten steel has the following chemical composition by weight percentage: C: 0.05–0.08%, Si: 0.15–0.30%, Mn: 1.30–1.55%, P: ≤0.012%, S: ≤0.004%, Nb: 0.015–0.030%, V: 0.030–0.045%, Ti: 0.010–0.020%, Cr: 0.1–0.25%, Ni: 0.15–0.30%, Mo: 0.15–0.30%, B: 0.0010–0.0020%, rare earth Ce: 0.0010–0.0020%, Pcm ≤0.22%, with the balance being Fe and unavoidable impurities.

[0036] S5 slab continuous casting: Employing dynamic light reduction at the end of solidification (8mm reduction), electromagnetic stirring (350A / 5HZ), weak cooling in the secondary cooling section, and straightening technology, the billet pulling speed is controlled at 0.8–1.0 m / min, and the superheat is 20–30℃, reducing defects such as center segregation and central porosity in the continuously cast billet. After the slab is removed from the line, it is slowly cooled for more than 48 hours, ultimately yielding high-quality slabs with a thickness of 250mm or 300mm and center segregation below C3.0.

[0037] S6 heating: The slab is heated in a walking beam furnace. The furnace atmosphere is strictly controlled to ensure a slightly reducing atmosphere and to guarantee the heating temperature and time of the slab. The heating temperature is controlled between 1200℃ and 1240℃, and the heating time is greater than 230 minutes to ensure the full solid solution of alloying elements and uniform slab temperature.

[0038] S7 Rolling and Cooling: Rolling employs a two-stage controlled rolling process, commonly referred to as the roughing stage and the finishing stage. Roughing is carried out on a 3800mm roughing mill, with an initial rolling temperature of 1160–1200℃, and the relative reduction rate per pass is controlled at least two passes above 14%. During finishing rolling, the deformation amount in each pass is strictly controlled, with an initial rolling temperature ≤950℃ and a final rolling temperature of 800–860℃. Controlled cooling is used after rolling, with a final cooling temperature of 640–670℃.

[0039] S8 Quenching and Tempering Heat Treatment: After shot blasting, the steel plate undergoes quenching. The quenching temperature is 910℃, and the furnace time is 20min + t × 1.4min / mm. The tempering temperature is 620℃~640℃, and the furnace time is 40min + t × 3.2min / mm, where t is the steel plate thickness in mm.

[0040] The present invention will now be described in detail with reference to actual embodiments.

[0041] Table 1 lists the chemical composition of the examples, and Table 2 lists the rolling and heat treatment process parameters of the examples.

[0042] Table 1 Chemical composition (wt%) of embodiments of the present invention

[0043]

[0044]

[0045] Table 2 Rolling and heat treatment process parameters of the embodiments of the present invention

[0046]

[0047] The mechanical properties, low-temperature impact properties, cold bending properties, and simulated post-weld heat treatment properties of the steel plates in the embodiments of the present invention were tested, and the results are shown in Tables 3 and 4.

[0048] Table 3 Mechanical properties of the steel plates in the embodiments of the present invention

[0049]

[0050]

[0051] A series of temperature impact tests were conducted on the steel plate according to GB / T229, and the results are shown in Table 4. The ductile-brittle transition temperature of the steel plate is -100℃, and it exhibits excellent low-temperature toughness.

[0052] Table 4. Temperature Shock Energy of Steel Plate Series in Example 3

[0053] Test temperature / °C Transverse impact work value / J 20 300、289、321 0 307、313、331 -20 316、306、312 -40 314、310、305 -50 309、310、320 -60 305、265、325 -80 228、236、256 -100 193、202、38

[0054] This invention employs a low-carbon Nb-V-Ti-Ni-Cr-Mo-B-RE composition design and a specific production process to obtain a Q550CFE high-strength, easily weldable steel plate specifically for compressed air energy storage. The plate exhibits a yield strength ≥550MPa, tensile strength 670-830MPa, elongation after fracture ≥16%, and longitudinal impact energy ≥200J at -40℃. It also possesses excellent weldability, corrosion resistance, and fatigue resistance.

[0055] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A high-strength, easily weldable steel plate for rare earth Q550CFE compressed air energy storage, characterized in that, The chemical composition of the steel plate, by weight percentage, is: C: 0.05-0.08%, Si: 0.15-0.30%, Mn: 1.30-1.55%, P: ≤0.012%, S: ≤0.004%, Nb: 0.015-0.030%, V: 0.030-0.045%, Ti: 0.010-0.020%, Cr: 0.1-0.25%, Ni: 0.15-0.30%, Mo: 0.15-0.30%, B: 0.0010-0.0020%, rare earth Ce: 0.0010-0.0020%, Pcm ≤0.22%, with the balance being Fe and unavoidable impurities.

2. The rare earth Q550CFE high-strength easy-to-weld steel plate for compressed air energy storage according to claim 1, characterized in that, The chemical composition of the steel plate, by weight percentage, is: C: 0.06%, Si: 0.22%, Mn: 1.47%, P: 0.010%, S: 0.002%, Nb: 0.016%, V: 0.032%, Ti: 0.015%, Cr: 0.17%, Ni: 0.18%, Mo: 0.18%, B: 0.0012%, rare earth Ce: 0.0011%, with the balance being Fe and unavoidable impurities.

3. The rare earth Q550CFE high-strength easy-to-weld steel plate for compressed air energy storage according to claim 1, characterized in that, The chemical composition of the steel plate, by weight percentage, is: C: 0.07%, Si: 0.15%, Mn: 1.42%, P: 0.011%, S: 0.002%, Nb: 0.018%, V: 0.033%, Ti: 0.013%, Cr: 0.16%, Ni: 0.18%, Mo: 0.17%, B: 0.0014%, rare earth Ce: 0.0012%, with the balance being Fe and unavoidable impurities.

4. The rare earth Q550CFE high-strength easy-to-weld steel plate for compressed air energy storage according to claim 1, characterized in that, The chemical composition of the steel plate, by weight percentage, is: C: 0.07%, Si: 0.15%, Mn: 1.43%, P: 0.012%, S: 0.002%, Nb: 0.019%, V: 0.031%, Ti: 0.015%, Cr: 0.17%, Ni: 0.15%, Mo: 0.18%, B: 0.0013%, rare earth Ce: 0.0011%, with the balance being Fe and unavoidable impurities.

5. The rare earth Q550CFE high-strength easy-to-weld steel plate for compressed air energy storage according to claim 1, characterized in that, The chemical composition of the steel plate, by weight percentage, is: C: 0.07%, Si: 0.16%, Mn: 1.40%, P: 0.009%, S: 0.002%, Nb: 0.018%, V: 0.035%, Ti: 0.014%, Cr: 0.16%, Ni: 0.16%, Mo: 0.20%, B: 0.0014%, rare earth Ce: 0.0014%, with the balance being Fe and unavoidable impurities.

6. The rare earth Q550CFE high-strength easy-to-weld steel plate for compressed air energy storage according to claim 1, characterized in that, The chemical composition of the steel plate, by weight percentage, is: C: 0.08%, Si: 0.17%, Mn: 1.42%, P: 0.009%, S: 0.001%, Nb: 0.020%, V: 0.035%, Ti: 0.016%, Cr: 0.17%, Ni: 0.17%, Mo: 0.21%, B: 0.0015%, rare earth Ce: 0.0018%, with the balance being Fe and unavoidable impurities.

7. The method for manufacturing a high-strength, easily weldable steel plate for rare earth Q550CFE compressed air energy storage according to any one of claims 1-6, characterized in that, The main steps and process parameters are as follows: S1 molten iron pretreatment: After desulfurization and dephosphorization of molten iron by KR stirring method, ensure that S≤0.005% and P≤0.013% in molten iron; S2 converter smelting: The converter smelting stage uses desulfurized pretreated molten iron and high-quality scrap steel as raw materials. The added quicklime, dolomite, alloys, deoxidizers, cored wire and various slag-forming materials must meet national standards. The molten iron temperature is ≥1260℃. The phosphorus and carbon content is reduced through efficient top and bottom blowing and other technologies to ensure that the molten steel has P≤0.010% and S≤0.004%. S3 LF Ladle Refining: The ladle refining stage precisely controls the steel composition, deoxidizes and alloys, and further reduces non-metallic inclusions and harmful impurities in the steel, with S≤0.004%, to obtain clean steel; the amount of quicklime added is ≥5kg / ton of steel, and the slag sample must be dipped during the refining process to ensure rapid formation of white slag and to keep the white slag for a certain period of time; S4 RH Vacuum Treatment: This treatment mode further reduces the content of hydrogen, oxygen, and nitrogen gases in molten steel, minimizing the adverse effects of harmful gases on the steel quality. To ensure the effective boron content in the steel, ferrotitanium is added first, followed by ferroboronium during RH vacuum treatment. The vacuum time is maintained at more than 20 minutes, the pure degassing time is greater than 15 minutes, and the soft blowing time is greater than 15 minutes. S5 slab continuous casting: adopts dynamic light pressure at the end of solidification, electromagnetic stirring, weak cooling in the second cooling section and straightening technology, the billet pulling speed is controlled at 0.8~1.0m / min and the superheat is 20~30℃; after the slab is removed from the line, it is slowly cooled for more than 48 hours, and finally a high-quality slab with a thickness of 250mm or 300mm and a center segregation of C3.0 or less is obtained. S6 heating: The slab is heated in a walking beam furnace. The furnace atmosphere is strictly controlled to ensure the heating temperature and time of the slab. The heating temperature is controlled at 1200℃~1240℃ and the heating time is greater than 230min to ensure the full solid solution of alloying elements and uniform slab temperature. S7 Rolling and Cooling: Rolling adopts a two-stage controlled rolling process, commonly referred to as the roughing stage and the finishing stage; roughing is carried out on a 3800mm roughing mill, with an initial rolling temperature of 1160-1200℃, and the relative reduction rate per pass is controlled at least 14% for at least two passes; during finishing, the deformation of each pass is strictly controlled, with an initial finishing rolling temperature ≤950℃ and a final rolling temperature of 800-860℃; the rolled steel plate is cooled under controlled conditions, with a final cooling temperature of 640-670℃; S8 Quenching and Tempering Heat Treatment: After shot blasting, the steel plate is quenched. The quenching temperature is 910℃, and the furnace time is 20min + t × 1.4min / mm. The tempering temperature is 620℃~640℃, and the furnace time is 40min + t × 3.2min / mm, where t is the thickness of the steel plate in mm.

Images