Heat-resistant steel plate for ultra-supercritical power station and manufacturing method of heat-resistant steel plate

Abstract

The invention discloses a heat-resistant steel plate for an ultra-supercritical power station. The heat-resistant steel plate comprises the following chemical components in percentage by mass: 0.09%-0.11% of C, 0.20%-0.50% of Si, 0.40%-0.50% of Mn and Plt. 0.015%, Slt; the alloy comprises the following components in percentage by weight: 0.005% of Fe, 8.60%-9.00% of Cr, 0.10%-0.20% of Ni, 0.35%-0.45% of Mo, less than or equal to 0.10% of Cu, 0.05%-0.08% of Nb, 0.16%-0.20% of V, less than or equal to 0.01% of Ti, less than or equal to 0.015% of Alt, 0.035%-0.065% of N, 1.55%-1.80% of W, 0.0015%-0.0040% of B, less than or equal to 0.010% of Zr and the balance of Fe and impurities. The preparation method comprises the working procedures of smelting, blank slow cooling, heating, rolling and heat treatment. According to the method, the problem of producing ultralow-carbon, high-purity and high-alloy steel in a converter process is solved, an electric furnace is replaced by the converter to serve as a primary smelting furnace, the production efficiency is higher, and energy consumption and cost for smelting per ton of steel are reduced by about 20%-30%; meanwhile, the product quality is excellent and stable, and the molten steel purity is high.

Description

Technical Field

[0001] This invention relates to the field of metallic materials technology, and in particular to a heat-resistant steel plate for ultra-supercritical power plants and its manufacturing method. Background Technology

[0002] With the continuous progress of my country's power industry, the requirements for boiler thermal efficiency are increasing. To enhance the energy efficiency of generating units and promote energy conservation and carbon reduction, the development of large-capacity, high-parameter ultra-supercritical thermal power generating units has become a clear trend. Against this backdrop, the application scale of ultra-supercritical units is gradually expanding, and the operating steam temperature and pressure are constantly increasing, placing more stringent requirements on the performance of key component materials. Researchers in the metallurgical field are actively engaged in the development of new heat-resistant steels, especially focusing on high-chromium heat-resistant steels with a chromium content of 9%–12%. This type of steel, with its excellent strength and toughness, creep resistance, and superior high-temperature oxidation and corrosion resistance, has received considerable attention from the industry and is gradually becoming the preferred or upgraded material for core equipment in thermal power plants.

[0003] SA-1017Gr92 steel (i.e., T92 / P92) belongs to the 9% chromium series of heat-resistant steels. It is a new type of ferritic heat-resistant steel developed based on ASME SA-387Gr91 (T91 / P91) through optimized alloy composition. Its main alloy design strategy is to appropriately reduce molybdenum content and increase tungsten content, thereby enhancing the solid solution strengthening effect and exhibiting superior high-temperature structural stability and creep strength. This material is suitable for manufacturing boiler superheaters and reheaters operating in the range of 580–620℃, making it an ideal choice for high-temperature and high-pressure conditions.

[0004] Currently, the production processes for T92 / P92 steel forgings and seamless tubes of the same composition series are relatively mature; however, the development of steel plate products lags behind. In response to this situation, there is an urgent need to develop a SA-1017Gr92 steel plate manufacturing technology that can achieve precise control of chemical composition, innovative production processes, and improved production efficiency, aiming to achieve synergistic optimization between material properties and production economics. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a heat-resistant steel plate for ultra-supercritical power plants and its manufacturing method.

[0006] To solve the above technical problems, the technical solution of the present invention is as follows: A heat-resistant steel plate for ultra-supercritical power plants has the following chemical composition and mass percentage: C: 0.09%-0.11%, Si: 0.20%-0.50%, Mn: 0.40%-0.50%, P<0.015%, S<0.005%, Cr: 8.60%-9.00%, Ni: 0.10%-0.20%, Mo: 0.35%-0.45%, Cu≤0.10%, Nb: 0.05%-0.08%, V: 0.16%-0.20%, Ti≤0.01%, Alt≤0.015%, N: 0.035%-0.065%, W: 1.55%-1.80%, B: 0.0015%-0.0040%, Zr≤0.010%, with the remainder being Fe and impurities.

[0007] Among them, carbon (C): C is the most important strengthening element in steel, which can significantly increase the strength and hardness of steel. However, excessive carbon content will cause carbide aggregation and spheroidization, affecting high-temperature creep performance. If the carbon content is too low, the strength of steel cannot be guaranteed. This invention uses 0.09 to 0.11% carbon element.

[0008] Manganese (Mn): Mn can form a pure solid solution with Fe, improve the crystal structure, and increase the yield strength and hardness of steel. At the same time, it can also increase the tensile strength of steel through the dispersion strengthening effect of grain boundaries. This invention uses 0.40%-0.50% manganese.

[0009] Chromium (Cr): Chromium is a key element in improving the oxidation and corrosion resistance of heat-resistant steel, enhancing its antioxidant and corrosion resistance. It also provides solid solution strengthening, increasing the bonding strength between matrix atoms and improving the steel's creep strength and creep limit. Furthermore, chromium can raise the FeO formation temperature and improve the high-temperature chemical stability of steel. This invention uses 8.60%-9.00% chromium.

[0010] Molybdenum (Mo): Molybdenum is a key element for improving the thermal strength of low-alloy heat-resistant steel. It dissolves into the matrix to provide solid solution strengthening. Increasing the recrystallization temperature of the steel also allows for the precipitation of a stable phase, further enhancing thermal strength. However, the oxides formed by molybdenum have a melting point of only 795°C, which deteriorates the steel's oxidation resistance. Therefore, excessive amounts cannot be added. This invention uses 0.35%-0.45% molybdenum.

[0011] Nickel (Ni): Nickel is mainly added to improve the processing properties of steel and obtain an austenitic structure, with little impact on oxidation resistance. Nickel has a certain degree of corrosion resistance, is chemically inert, and is not easily oxidized. In particular, it does not easily combine with sulfur and chloride ions, giving the alloy high structural stability. This invention uses 0.10%-0.20% nickel.

[0012] Niobium (Nb) and vanadium (V): These elements can form stable carbides, improving the relaxation stability and hot strength of steel. When steel contains elements such as Mo and Cr, it can promote the entry of these elements into the solid solution, improving high-temperature strength. This invention uses 0.05%-0.08% niobium and 0.16%-0.20% vanadium.

[0013] Boron (B): Boron can significantly improve the hardenability of steel. Its mechanism of action is to inhibit the nucleation of ferrite at grain boundaries during the decomposition of austenite at high temperature, delay the phase transformation process, and thus increase the effective hardenability depth. Boron can also produce grain boundary strengthening and improve long-term plasticity. This invention uses 0.0015%-0.0040% boron.

[0014] Nitrogen (N): The solid solution strengthening effect of nitrogen can significantly improve the hardenability and hardness of steel. Under high temperature conditions, the precipitation of nitrides will induce precipitation hardening, which will further improve the strength and hardness of steel. In addition, nitrogen can enhance the creep resistance of steel, especially in long-term high-temperature use scenarios, and can effectively resist deformation and crack propagation. High-chromium steel containing nitrogen exhibits better creep strength and stability at high temperatures. This invention uses 0.035%-0.065% nitrogen.

[0015] At the same time, it is necessary to control the content of harmful elements such as P and S. Combined with precise control of segregation in continuous casting billets, high-quality billets with C1.0 grade central segregation were obtained to ensure the quality of the steel plate core. After normalizing and tempering, the main microstructure of the steel plate is tempered martensite.

[0016] In a further preferred embodiment of the present invention, the thickness of the heat-resistant steel plate ranges from 6 to 100 mm, the steel plate microstructure is tempered martensite, the yield strength is ≥440 MPa, the tensile strength is 620-840 MPa, the elongation at section is ≥20%, and the longitudinal impact absorption energy at 20℃ is ≥54 J.

[0017] This invention also provides a method for preparing heat-resistant steel plates for ultra-supercritical power plants, including smelting, slow cooling of billets, heating, rolling, and heat treatment processes, the specific steps of which are as follows: S1: Smelting process: Iron pretreatment to remove sulfur, converter deep desulfurization, LF deep desulfurization, and RH deep desulfurization are adopted; dynamic light pressure and electromagnetic stirring technology are used to obtain a continuous casting slab with a specification of 220×2070mm. S2: Slow cooling process of billet: After the billet comes off the production line, it is immediately transferred to the heat preservation pit for heat preservation. The temperature in the pit is controlled at 300-600℃, and the heat preservation is carried out at 600~800℃ for more than 72 hours. S3: Heating process: The billet is heated in a car-bottom heating furnace at a temperature of 1250±30℃. S4: Rolling process: One-stage rolling, completed with the fewest rolling passes, and the steel plate is inspected and accepted by ASTM A578C ultrasonic testing after rolling; S5: Heat treatment process: The steel plate adopts offline normalizing + tempering heat treatment. The normalizing temperature is 1050±10℃, the furnace time is (3.5min / mm×t)±20min, where t is the thickness of the steel plate, and it is air-cooled after normalizing; the tempering temperature is 750±10℃, the furnace time is (7.5min / mm×t)±20min, where t is the thickness of the steel plate, and it is air-cooled after tempering.

[0018] In a further preferred embodiment of the present invention, the smelting process in S1 specifically comprises: pre-treatment of molten iron to reduce the sulfur content to below 0.003%; then transferring it to a converter for blowing, controlling the appropriate oxygen supply intensity and slag formation to reduce the phosphorus content to below 0.012%; next, transferring the molten steel to an LF refining furnace for deep desulfurization, deoxidation, and alloying operations, and precisely adjusting the chemical composition; finally, degassing treatment in an RH vacuum refining furnace, with a high vacuum degree ≤ 5.0 mbar and a holding time ≥ 20 min; after RH treatment, feeding 150-200 meters / furnace of seamless pure calcium wire, and static stirring time ≥ 20 min after wire feeding; finally, transferring it to the continuous casting process, using protective casting and electromagnetic stirring technology to cast 220mm, 260mm, and 320mm continuous casting billets.

[0019] In a further preferred embodiment of the present invention, the S3 heating process specifically comprises: the billet entering the furnace at a temperature ≤300℃, first heating it to 650-800℃ at a rate ≤80℃ / h, holding it for ≥2 hours, then heating it to 950℃ at a rate ≤80℃ / h, holding it for ≥2 hours, and finally heating it to 1250±30℃ at a rate ≤100℃ / h, holding it for ≥2 hours.

[0020] In a further preferred embodiment of the present invention, the initial rolling temperature in the S4 rolling process is ≥1100℃ and the final rolling temperature is ≥820℃.

[0021] The beneficial effects of this invention are: This invention solves the problem of producing ultra-low carbon, high-purity, and high-alloy steel using a converter process. By replacing the electric furnace with a converter as the primary refining furnace, production efficiency is higher, and energy consumption and cost per ton of steel are reduced by approximately 20%-30%. Simultaneously, the product quality is excellent and stable, with high purity of molten steel ([S]≤0.002%, [P]≤0.010%, [H]≤1.5ppm); uniform composition; alloying elements controlled within a very narrow range; effective control of segregation and porosity at the center of the billet; and mechanical properties that fully meet and exceed the requirements of the ASME SA-1017M standard, especially with minimal fluctuations in impact toughness and more stable performance. The present invention employs a staged heat preservation and slow cooling method in a heat preservation pit for continuous casting billets, which effectively avoids the risk of scrapping due to defects such as corner cracks and transverse cracks, and improves the billet qualification rate. This invention uses 220-320mm thick continuously cast billets, one-stage rolling, high-temperature normalizing + tempering heat treatment, to produce SA-1017Gr92 steel plates with a minimum thickness of 6mm and a maximum thickness of 100mm. The plates pass ASTM A578C ultrasonic testing, have uniform composition and excellent comprehensive mechanical properties, moderate strength, good strength-toughness matching, and an impact absorption energy of ≥100J at 20℃. This invention enables economical and mass production of steel plates, meeting the requirements for use in the harsh environment of ultra-supercritical power plants with high temperature and high pressure. Detailed Implementation

[0022] To make the content of this invention easier to understand, the invention will be further described in detail below based on specific embodiments. Example 1

[0023] This embodiment provides an SA-1017Gr92 heat-resistant steel plate for ultra-supercritical power plants, with a thickness of 6 mm. Its chemical composition and mass percentage are as follows: C: 0.10%, Si: 0.33%, Mn: 0.43%, P: 0.012%, S: 0.002%, Cr: 8.8%, Ni: 0.15%, Cu: 0.02%, Mo: 0.36%, V: 0.17%, Nb: 0.06%, Ti: 0.0019%, Al: 0.008%, W: 1.59%, B: 0.0019%, Zr: 0.0039%, N: 444 ppm, with the remainder being Fe and impurities.

[0024] The above-mentioned steel plate production method includes the following steps: Steelmaking process: Hot metal pretreatment is used to reduce the sulfur content of the hot metal to below 0.003%; then it is transferred to a converter for blowing, and the appropriate oxygen supply intensity and slag formation are controlled to reduce the phosphorus content to below 0.012%; next, the hot metal is transferred to an LF refining furnace for deep desulfurization, deoxidation and alloying operations, and the chemical composition is precisely adjusted; finally, it is degassed in an RH vacuum refining furnace, with a high vacuum of 3.0 mbar held for 22 minutes. After RH is completed, 180 meters of seamless pure calcium wire is fed in per furnace. After the wire feeding is completed, the wire is stirred for 25 minutes. Finally, it is transferred to the continuous casting process, using protective casting and electromagnetic stirring technology to obtain a continuous casting slab with a specification of 220×2070mm. Slow cooling process of billet: After the billet comes off the production line, it is immediately transferred to the heat preservation pit for heat preservation. The temperature in the pit is controlled at 506℃, and the heat preservation is carried out at 600~800℃ for 80.5 hours. Heating process: The billet is heated in a car-bottom heating furnace with an initial furnace temperature of 201℃ and a final heating temperature of 1253℃. The total heating time is 21.6 hours. Rolling process: One-stage rolling process is adopted, with an initial rolling temperature of 1187℃ and a final rolling temperature of 833℃. There are 17 rolling passes. The steel plate passes the ultrasonic test of ASTM A578C. Heat treatment process: After the steel plate is trimmed, it is normalized and tempered. The normalizing temperature is 1052℃ and the total time in the furnace is 31min. After being taken out of the furnace, it is air-cooled. The tempering temperature is 750℃ and the total time in the furnace is 55min. After being taken out of the furnace, it is air-cooled.

[0025] The mechanical properties are: yield strength 640MPa, tensile strength 780MPa, elongation after fracture 23.5%, transverse cold bending qualified, impact absorption energy Akv at 20℃: 77J, 86J, 82J, average 82J (sample size 5×10×55mm).

[0026] The metallographic structure is tempered martensite. Example 2

[0027] This embodiment provides an SA-1017Gr92 heat-resistant steel plate for ultra-supercritical power plants, with a thickness of 30.3 mm. Its chemical composition and mass percentage are as follows: C: 0.11%, Si: 0.34%, Mn: 0.44%, P: 0.010%, S: 0.002%, Cr: 8.9%, Ni: 0.16%, Cu: 0.02%, Mo: 0.37%, V: 0.19%, Nb: 0.07%, Ti: 0.002%, Al: 0.010%, W: 1.61%, B: 0.0021%, Zr: 0.0035%, N: 426 ppm, with the remainder being Fe and impurities.

[0028] The above-mentioned steel plate production method includes the following steps: Steelmaking process: Hot metal pretreatment is used to reduce the sulfur content of the hot metal to below 0.003%; then it is transferred to a converter for blowing, and the appropriate oxygen supply intensity and slag formation are controlled to reduce the phosphorus content to below 0.012%; next, the hot metal is transferred to an LF refining furnace for deep desulfurization, deoxidation and alloying operations, and the chemical composition is precisely adjusted; finally, it is degassed in an RH vacuum refining furnace, with a high vacuum of 3.0 mbar held for 22 minutes. After RH is completed, 180 meters of seamless pure calcium wire is fed in per furnace. After the wire feeding is completed, the static stirring time is 28 minutes. Finally, it is transferred to the continuous casting process, using protective casting and electromagnetic stirring technology to obtain a continuous casting slab with a specification of 260×2070mm. Slow cooling process of billet: After the billet comes off the production line, it is immediately transferred to the heat preservation pit for heat preservation. The temperature in the pit is controlled at 566℃, and the heat preservation is carried out at 600~800℃ for 82.4 hours. Heating process: The billet is heated in a car-bottom heating furnace with an initial furnace temperature of 284℃ and a final heating temperature of 1251℃. The total heating time is 22.4 hours. Rolling process: One-stage rolling process is adopted, with an initial rolling temperature of 1194℃ and a final rolling temperature of 987℃. There are 15 rolling passes. The steel plate passes the ultrasonic test of ASTM A578C. Heat treatment process: After the steel plate is trimmed, it is normalized and tempered. The normalizing temperature is 1050℃ and the total time in the furnace is 116 minutes. After being taken out of the furnace, it is air-cooled. The tempering temperature is 748℃ and the total time in the furnace is 238 minutes. After being taken out of the furnace, it is air-cooled.

[0029] The mechanical properties are: yield strength 595MPa, tensile strength 745MPa, elongation after fracture 24%, transverse cold bending qualified, impact absorption energy Akv at 20℃: 176J, 171J, 186J, average 178J (sample size 10×10×55mm).

[0030] The metallographic structure is tempered martensite. Example 3

[0031] This embodiment provides an SA-1017Gr92 heat-resistant steel plate for ultra-supercritical power plants, with a thickness of 100mm. Its chemical composition and mass percentage are as follows: C: 0.10%, Si: 0.32%, Mn: 0.43%, P: 0.009%, S: 0.001%, Cr: 8.8%, Ni: 0.16%, Cu: 0.02%, Mo: 0.35%, V: 0.17%, Nb: 0.06%, Ti: 0.0016%, Al: 0.009%, W: 1.58%, B: 0.0023%, Zr: 0.0037%, N: 487ppm, with the remainder being Fe and impurities.

[0032] The above-mentioned steel plate production method includes the following steps: Steelmaking process: Hot metal pretreatment is performed to reduce the sulfur content to below 0.003%; then it is transferred to a converter for blowing, with appropriate oxygen supply intensity and slag formation controlled to reduce the phosphorus content to below 0.012%; next, the hot metal is transferred to an LF refining furnace for deep desulfurization, deoxidation and alloying operations, and the chemical composition is precisely adjusted; finally, it is degassed in an RH vacuum refining furnace with a high vacuum of 3.0 mbar for 22 minutes. After RH is completed, 180 meters of seamless pure calcium wire is fed per furnace, and the static stirring time is 30 minutes after wire feeding. Finally, it is transferred to the continuous casting process, using protective casting and electromagnetic stirring technology to obtain a continuous casting slab with a specification of 320×2070mm. Slow cooling process of billet: After the billet comes off the production line, it is immediately transferred to the heat preservation pit for heat preservation. The temperature in the pit is controlled at 586℃, and the heat preservation is carried out at 600~800℃ for 90.3 hours. Heating process: The billet is heated in a car-bottom heating furnace with an initial furnace temperature of 263℃ and a final heating temperature of 1248℃. The total heating time is 23.4 hours. Rolling process: One-stage rolling process is adopted, with an initial rolling temperature of 1185℃ and a final rolling temperature of 1014℃. There are 13 rolling passes. The steel plate passes the ultrasonic test of ASTM A578C. Heat treatment process: After the steel plate is trimmed, it is normalized and tempered. The normalizing temperature is 1050℃ and the total time in the furnace is 350min. After being taken out of the furnace, it is air-cooled. The tempering temperature is 749℃ and the total time in the furnace is 750min. After being taken out of the furnace, it is air-cooled.

[0033] The mechanical properties are: yield strength 570MPa, tensile strength 725MPa, elongation after fracture 23%, transverse cold bending qualified, impact absorption energy Akv at 20℃: 226J, 215J, 200J, average 214J (sample size 10×10×55mm).

[0034] The metallographic structure is tempered martensite.

[0035] In summary, this invention employs a composite composition design with added Cr and Mo elements, strict control of P and S elements, and utilizes continuous casting electromagnetic stirring and precise control technology for C-type segregation in continuously cast billets. High-temperature heating and one-stage rolling are employed to produce high-performance SA387Gr11Cl2 steel plates. SA387Gr11Cl2 steel plates in 12.7mm, 17.9mm, and 28mm specifications meet the performance requirements of ASTM A387 standard. The steel plates have a bainitic microstructure, and flaw detection meets ASTM A578 Class C requirements. The yield strength of the steel plates ranges from 420MPa to 520MPa, the tensile strength ranges from 560MPa to 640MPa, the transverse impact energy at 0℃ is ≥300J, and the steel plates exhibit excellent weldability. This invention enables economical and mass production of the steel plates, meeting the usage requirements under various complex working conditions in the petrochemical industry. In summary, this invention successfully developed a high-performance SA1017Gr92 heat-resistant steel plate with a thickness of 6-100mm by adopting a converter-LF-RH-continuous casting-heating-rolling-heat treatment production process. The steel plate meets the performance requirements of ASME SA-1017 standard, has a tempered martensitic microstructure, meets the ASTM A578 Class C requirements for flaw detection, has a yield strength distribution between 550MPa and 620MPa, a tensile strength distribution between 700MPa and 800MPa, and an impact absorption energy of ≥100J at 20℃. This invention represents a new breakthrough in the high-efficiency production of SA1017Gr92 heat-resistant steel in medium and heavy plate production lines. The modified process simplifies the process flow, shortens the smelting time, and reduces production costs. It also provides new ideas and process models for the research and development of similar 9-12%Cr series alloy steels, and has significant engineering application value and industry promotion significance.

[0036] In addition to the above embodiments, the present invention may have other implementation methods; all technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A heat-resistant steel plate for ultra-supercritical power stations, having the following chemical composition and mass percentage: C: 0.09%-0.11%, Si: 0.20%-0.50%, Mn: 0.40%-0.50%, P <0.015%, S <0.005%, Cr: 8.60%-9.00%, Ni: 0.10%-0.20%, Mo: 0.35%-0.45%, Cu≤0.10%, Nb: 0.05%-0.08%, V: 0.16%-0.20%, Ti≤0.01%, Alt≤0.015%, N: 0.035%-0.065%, W: 1.55%-1.80%, B: 0.0015%-0.0040%, Zr≤0.010%, and the remainder being Fe and impurities.

2. The heat-resistant steel plate for ultra-supercritical power plants according to claim 1, characterized by: The heat-resistant steel plate has a thickness range of 6-100 mm, a microstructure of tempered martensite, a yield strength ≥440 MPa, a tensile strength of 620-840 MPa, an elongation ≥20%, and a longitudinal impact energy at 20°C ≥54 J.

3. The method of claim 1, wherein the method further comprises: The process comprises smelting, billet slow cooling, heating, rolling, and heat treatment steps, and the specific steps are as follows: ​ S1: smelting step: adopting hot metal pretreatment to reduce the sulfur content to below 0.003%, then transferring into a converter for blowing, controlling the oxygen supply intensity and slagging system to reduce the phosphorus content to below 0.012%, then transferring the molten steel into an LF refining furnace for deep desulfurization, deoxidation, and alloying operations, and accurately adjusting the chemical composition, and finally performing degassing treatment in an RH vacuum refining furnace, maintaining a high vacuum degree of ≤5.0 mbar for ≥20 min, feeding 150-200 meters of seamless pure calcium wire per furnace after the RH ends, maintaining the static stirring time for ≥20 min after the wire feeding ends, and finally transferring into a continuous casting process to cast 220 mm, 260 mm, and 320 mm continuous casting billets by using electromagnetic stirring technology. S2: billet slow cooling step: immediately transferring the casting billet into a holding pit for heat preservation after the casting billet is discharged, controlling the pit temperature to 300-600°C, and adopting 600-800°C heat preservation for a slow cooling time of ≥72 hours; S3: heating step: heating the casting billet in a car-bottom heating furnace, and adopting a heating temperature of 1250±30°C; S4: rolling step: one-stage rolling, adopting minimum pass rolling to end, and adopting ASTM A578C ultrasonic detection to accept the steel plate after rolling; S5: heat treatment step: adopting offline normalizing + tempering heat treatment for the steel plate, adopting a normalizing temperature of 1050±10°C, a furnace time of (3.5 min / mm×t)±20 min, t being the thickness of the steel plate, and air cooling after normalizing; adopting a tempering temperature of 750±10°C, a furnace time of (7.5 min / mm×t)±20 min, t being the thickness of the steel plate, and air cooling after tempering.

4. The method of producing a heat-resistant steel plate for ultra-supercritical power plants according to claim 3, characterized in that: ​ 5. The method of claim 3, wherein the method further comprises: The S3 heating process is specifically: the billet furnace temperature is less than or equal to 300 DEG C, first using a rate of less than or equal to 80 DEG C / h to heat to 650-800 DEG C, the holding time is greater than or equal to 2 hours, then the heating rate is less than or equal to 80 DEG C / h to heat to 950 DEG C, the holding time is greater than or equal to 2 hours, finally the heating rate is less than or equal to 100 DEG C / h to heat to 1250±30 DEG C, the holding time is greater than or equal to 2 hours. ​ 6. The method of producing a heat-resistant steel plate for ultra-supercritical power plants according to claim 3, characterized in that: The S4 rolling process is that the open rolling temperature is greater than or equal to 1100 DEG C, and the finish rolling temperature is greater than or equal to 820 DEG C.