Rolling method of Ni-added steel plate for nuclear power project
By wrapping carbon steel scale in steel plates used in nuclear power projects and adopting a three-stage controlled rolling and cooling process, the problem of iron oxide scale on the surface of Ni steel plates was solved, enabling the production of high-performance nuclear power steel plates that meet the requirements for use in low-temperature environments.
Patent Information
- Application Number
- CN202511034489.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-25
- Publication Date
- 2025-11-25
AI Technical Summary
When high levels of Ni alloy are added to steel plates used in nuclear power projects, the resulting surface oxide scale is high and the low-temperature toughness is poor, making it difficult to meet the requirements of nuclear power projects.
The steel plate is made by wrapping carbon steel scale with continuously cast billets and using a three-stage controlled rolling and cooling process, including large reduction rolling, multiple high-pressure water cooling and two-phase rolling, to ensure that the steel plate surface is smooth and free of loose iron oxide scale. The performance is improved by quenching and tempering heat treatment.
The steel plate has a smooth surface without loose iron oxide scale, excellent performance, yield strength and tensile strength reaching a certain level, excellent low-temperature impact resistance, and improved market competitiveness.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of metallurgy, and particularly relates to a rolling method of a Ni-added steel plate for a nuclear power project. BACKGROUND
[0002] After a common carbon steel is added with a high Ni alloy, the surface scale of the steel plate after heat treatment is relatively high. Meanwhile, the steel plate for a nuclear power project is used in a low-temperature environment, and good low-temperature toughness is required. Therefore, the above problems are perfectly solved through the test method. SUMMARY
[0003] The application aims to provide a rolling method of a Ni-added steel plate for a nuclear power project, and the obtained steel plate has a smooth surface without loose scale and excellent performance.
[0004] To solve the above technical problems, the application adopts the following technical scheme: A rolling method of a Ni-added steel plate for a nuclear power project, comprising continuous casting blank heating, high-pressure water phosphorus removal, III-stage controlled rolling and controlled cooling; the III-stage controlled rolling and controlled cooling is specifically as follows: in the first stage, large reduction is adopted for rolling, and the pass reduction is 30mm-45mm, and the rolling is ended after spreading; in the second stage, the steel is cooled to 900-920 DEG C for rough rolling, the pass reduction is controlled to be 25mm-35mm, and the rolling process is cooled by high-pressure water multiple times; in the third stage, the steel is cooled to a thickness H+(40-70)mm, the rough rolling temperature is 800-820 DEG C, and the finish rolling temperature is greater than or equal to 750 DEG C; after the steel plate is rolled, the steel plate enters ACC cooling, and the re-drying temperature is controlled to be below 600 DEG C.
[0005] Further, before the continuous casting blank is heated, the carbon steel scale is adopted for wrapping.
[0006] Further, the thickness of the carbon steel scale is 1mm-2mm.
[0007] Further, the chemical composition of the steel plate is as follows: C: 0.10%-0.12%, Si: 0.15%-0.30%, Mn: 1.50%-1.60%, P≤0.010, S≤0.005%, Ni: 0.80%-0.90%, V: 0.020-0.030, and the rest is Fe and inevitable impurities.
[0008] Further, the thickness of the steel plate is 10mm-60mm.
[0009] After the steel plate is subjected to quenching + tempering heat treatment, the surface is smooth without loose scale; and the mechanical properties are as follows: yield strength R p0.2 ≥420MPa, tensile strength R m570MPa~720MPa, elongation after fracture A≥20%; impact energy at 1 / 2 thickness at -60℃ KV2≥47J.
[0010] The inventive principle of this invention lies in: When carbon steel is alloyed with a high amount of Ni, a relatively dense scale of iron oxide forms on the continuously cast billet after high-temperature heating. High-pressure water cannot completely remove this scale, resulting in uneven primary iron oxide scale on the surface of the rolled steel plate. By wrapping the continuously cast billet with a 1mm–2mm layer of carbon steel scale, direct oxidation during heating is prevented, and the scale is easily removed under high-pressure water, ensuring the surface condition of the steel plate.
[0011] The main purposes of adopting the three-stage controlled rolling are as follows: In the first stage, high-reduction rolling is used to break up the grains and reduce defects such as porosity and looseness inside the continuous casting billet, while completing the steel plate widening process; In the second stage, high-pressure water surface cooling and high-reduction rolling are used to facilitate the metal flow and deformation in the core of the continuous casting billet and initially refine the grains; In the third stage, two-phase rolling is used to further refine the microstructure, and water cooling after rolling ensures that the grains do not coarsen.
[0012] The beneficial effects of adopting the above technical solution are as follows: (1) The continuous casting billet is wrapped with carbon steel sheet, which reduces the cost of surface treatment of the steel plate in the later stage, and at the same time, the presence of the steel sheet will not cause the thickness of the steel plate to be uncontrollable.
[0013] (2) The adoption of stage III controlled rolling and cooling results in good overall performance, making the product more competitive and helping to increase market share. Detailed Implementation
[0014] The present invention will be further described in detail below with reference to specific embodiments. Example 1
[0015] In this embodiment, the nuclear power project uses Ni-added steel plates with a thickness of 10mm. The chemical composition and mass percentage are as follows: C: 0.10%, Si: 0.25%, Mn: 1.52%, P: 0.008%, S: 0.0012%, Ni: 0.83%, V: 0.020%, with the remainder being Fe and unavoidable impurities. The rolling method includes the following steps: (1) The continuous casting billet is wrapped with 1mm carbon steel sheet, heated, and dephosphorized by high pressure water. After dephosphorization, there is no iron oxide scale on the surface of the continuous casting billet. (2) Three-stage controlled rolling and controlled cooling are adopted, as detailed below: In the first stage, a large reduction rolling process is adopted, with a reduction of 30mm to 45mm per pass, and the rolling ends after widening. In the second stage, the steel is dried to 920℃ before rolling begins, with the reduction per pass controlled between 25mm and 35mm. The rolling process involves multiple high-pressure water cooling operations. In the third stage, the steel thickness is 80mm, the initial rolling temperature is 820℃, it is rolled in 7 passes, and the final rolling temperature is 750℃; after rolling, the steel plate enters ACC cooling, and the reddening temperature is 600℃.
[0016] The Ni-added steel plates used in this nuclear power project, after quenching and tempering heat treatment, have a smooth surface without loose iron oxide scale, and their mechanical properties are shown in Table 1. Example 2
[0017] In this embodiment, the nuclear power project uses Ni-added steel plates with a thickness of 10mm. The chemical composition and mass percentage are as follows: C: 0.11%, Si: 0.25%, Mn: 1.50%, P: 0.008%, S: 0.0012%, Ni: 0.80%, V: 0.021%, with the remainder being Fe and unavoidable impurities. The rolling method includes the following steps: (1) The continuous casting billet is wrapped with 1mm carbon steel sheet, heated, and dephosphorized by high pressure water. After dephosphorization, there is no iron oxide scale on the surface of the continuous casting billet. (2) Three-stage controlled rolling and controlled cooling are adopted, as detailed below: In the first stage, a large reduction rolling process is adopted, with a reduction of 30mm to 45mm per pass, and the rolling ends after widening. In the second stage, the steel is dried to 920℃ before rolling begins, with the reduction per pass controlled between 25mm and 35mm. The rolling process involves multiple high-pressure water cooling operations. In the third stage, the steel thickness is 80mm, the initial rolling temperature is 820℃, it is rolled in 7 passes, and the final rolling temperature is 752℃; after rolling, the steel plate enters ACC cooling, and the reddening temperature is 598℃.
[0018] The Ni-added steel plates used in this nuclear power project, after quenching and tempering heat treatment, have a smooth surface without loose iron oxide scale, and their mechanical properties are shown in Table 1. Example 3
[0019] In this embodiment, the nuclear power project uses Ni-added steel plates with a thickness of 15mm. The chemical composition and mass percentage are as follows: C: 0.11%, Si: 0.25%, Mn: 1.53%, P: 0.009%, S: 0.0015%, Ni: 0.83%, V: 0.021%, with the remainder being Fe and unavoidable impurities. The rolling method includes the following steps: (1) The continuous casting billet is wrapped with 1mm carbon steel sheet, heated, and dephosphorized by high pressure water. After dephosphorization, there is no iron oxide scale on the surface of the continuous casting billet. (2) Three-stage controlled rolling and controlled cooling are adopted, as detailed below: In the first stage, a large reduction rolling process is adopted, with a reduction of 30mm to 45mm per pass, and the rolling ends after widening. In the second stage, the steel is dried to 920℃ before rolling begins, with the reduction per pass controlled between 25mm and 35mm. The rolling process involves multiple high-pressure water cooling operations. In the third stage, the steel thickness is 70mm, the initial rolling temperature is 818℃, it is rolled in 7 passes, and the final rolling temperature is 765℃; after rolling, the steel plate enters ACC cooling, and the reddening temperature is 600℃.
[0020] The Ni-added steel plates used in this nuclear power project, after quenching and tempering heat treatment, have a smooth surface without loose iron oxide scale, and their mechanical properties are shown in Table 1. Example 4
[0021] In this embodiment, the nuclear power project uses Ni-added steel plates with a thickness of 25mm. The chemical composition and mass percentage are as follows: C: 0.12%, Si: 0.20%, Mn: 1.51%, P: 0.010%, S: 0.0020%, Ni: 0.81%, V: 0.024%, with the remainder being Fe and unavoidable impurities. The rolling method includes the following steps: (1) The continuous casting billet is wrapped with 1mm carbon steel sheet, heated, and dephosphorized by high pressure water. After dephosphorization, there is no iron oxide scale on the surface of the continuous casting billet. (2) Three-stage controlled rolling and controlled cooling are adopted, as detailed below: In the first stage, a large reduction rolling process is adopted, with a reduction of 30mm to 45mm per pass, and the rolling ends after widening. In the second stage, the steel is dried to 918℃ before rolling begins, with the reduction per pass controlled at 25mm to 35mm. The rolling process involves multiple high-pressure water cooling operations. In the third stage, the steel thickness is 85mm, the initial rolling temperature is 815℃, it is rolled in 7 passes, and the final rolling temperature is 768℃; after rolling, the steel plate enters ACC cooling, and the red-hot temperature is 585℃.
[0022] The Ni-added steel plates used in this nuclear power project, after quenching and tempering heat treatment, have a smooth surface without loose iron oxide scale, and their mechanical properties are shown in Table 1. Example 5
[0023] In this embodiment, the nuclear power project uses Ni-added steel plates with a thickness of 43mm. The chemical composition and mass percentage are as follows: C: 0.11%, Si: 0.24%, Mn: 1.56%, P: 0.010%, S: 0.0018%, Ni: 0.84%, V: 0.026%, with the remainder being Fe and unavoidable impurities. The rolling method includes the following steps: (1) The continuous casting billet is wrapped with 2mm carbon steel sheet, heated and dephosphorized by high pressure water. After dephosphorization, there is no iron oxide scale on the surface of the continuous casting billet. (2) Three-stage controlled rolling and controlled cooling are adopted, as detailed below: In the first stage, a large reduction rolling process is adopted, with a reduction of 30mm to 45mm per pass, and the rolling ends after widening. In the second stage, the steel is dried to 910℃ before rolling begins, with the reduction per pass controlled at 25mm to 35mm. The rolling process involves multiple high-pressure water cooling operations. In the third stage, the steel thickness is 95mm, the initial rolling temperature is 810℃, it is rolled in 5 passes, and the final rolling temperature is 770℃; after rolling, the steel plate enters ACC cooling, and the reddening temperature is 595℃.
[0024] The Ni-added steel plates used in this nuclear power project, after quenching and tempering heat treatment, have a smooth surface without loose iron oxide scale, and their mechanical properties are shown in Table 1. Example 6
[0025] In this embodiment, the nuclear power project uses Ni-added steel plates with a thickness of 50mm. The chemical composition and mass percentage are as follows: C: 0.10%, Si: 0.29%, Mn: 1.60%, P: 0.009%, S: 0.0018%, Ni: 0.88%, V: 0.027%, with the remainder being Fe and unavoidable impurities. The rolling method includes the following steps: (1) The continuous casting billet is wrapped with 2mm carbon steel sheet, heated and dephosphorized by high pressure water. After dephosphorization, there is no iron oxide scale on the surface of the continuous casting billet. (2) Three-stage controlled rolling and controlled cooling are adopted, as detailed below: In the first stage, a large reduction rolling process is adopted, with a reduction of 30mm to 45mm per pass, and the rolling ends after widening. In the second stage, the steel is dried to 905℃ before rolling begins, with the reduction per pass controlled at 25mm to 35mm. The rolling process involves multiple high-pressure water cooling operations. In the third stage, the steel thickness is 100mm, the initial rolling temperature is 804℃, it is rolled in 5 passes, and the final rolling temperature is 765℃; after rolling, the steel plate enters ACC cooling, and the reddening temperature is 580℃.
[0026] The Ni-added steel plates used in this nuclear power project, after quenching and tempering heat treatment, have a smooth surface without loose iron oxide scale, and their mechanical properties are shown in Table 1. Example 7
[0027] In this embodiment, the nuclear power project uses Ni-added steel plates with a thickness of 60mm. The chemical composition and mass percentage are as follows: C: 0.11%, Si: 0.29%, Mn: 1.58%, P: 0.009%, S: 0.0012%, Ni: 0.90%, V: 0.030%, with the remainder being Fe and unavoidable impurities. The rolling method includes the following steps: (1) The continuous casting billet is wrapped with 2mm carbon steel sheet, heated and dephosphorized by high pressure water. After dephosphorization, there is no iron oxide scale on the surface of the continuous casting billet. (2) Three-stage controlled rolling and controlled cooling are adopted, as detailed below: In the first stage, a large reduction rolling process is adopted, with a reduction of 30mm to 45mm per pass, and the rolling ends after widening. In the second stage, the steel is dried to 900°C before rolling begins, with the reduction per pass controlled at 25mm to 35mm. The rolling process involves multiple high-pressure water cooling operations. In the third stage, the steel thickness is 100mm, the initial rolling temperature is 810℃, it is rolled in 5 passes, and the final rolling temperature is 770℃; after rolling, the steel plate enters ACC cooling, and the reddening temperature is 560℃.
[0028] The Ni-added steel plates used in this nuclear power project, after quenching and tempering heat treatment, have a smooth surface without loose iron oxide scale, and their mechanical properties are shown in Table 1. Example 8
[0029] In this embodiment, the nuclear power project uses Ni-added steel plates with a thickness of 60mm. The chemical composition and mass percentage are as follows: C: 0.10%, Si: 0.29%, Mn: 1.60%, P: 0.008%, S: 0.0012%, Ni: 0.89%, V: 0.028%, with the remainder being Fe and unavoidable impurities. The rolling method includes the following steps: (1) The continuous casting billet is wrapped with 2mm carbon steel sheet, heated and dephosphorized by high pressure water. After dephosphorization, there is no iron oxide scale on the surface of the continuous casting billet. (2) Three-stage controlled rolling and controlled cooling are adopted, as detailed below: In the first stage, a large reduction rolling process is adopted, with a reduction of 30mm to 45mm per pass, and the rolling ends after widening. In the second stage, the steel is dried to 905℃ before rolling begins, with the reduction per pass controlled at 25mm~35mm, and the rolling process is cooled by high-pressure water multiple times. In the third stage, the steel thickness is 100mm, the initial rolling temperature is 800℃, it is rolled in 5 passes, and the final rolling temperature is 775℃; after rolling, the steel plate enters ACC cooling, and the reddening temperature is 575℃.
[0030] The Ni-added steel plates used in this nuclear power project, after quenching and tempering heat treatment, have a smooth surface without loose iron oxide scale, and their mechanical properties are shown in Table 1.
[0031] Table 1 Mechanical properties of steel plates in various embodiments
[0032] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A rolling method for Ni-added steel plates used in nuclear power projects, characterized in that, The process includes continuous casting billet heating, high-pressure water descaling, and three-stage controlled rolling and cooling. The three-stage controlled rolling and cooling process is as follows: In the first stage, large reduction rolling is adopted, with a reduction of 30mm to 45mm per pass, and rolling ends after widening; In the second stage, the steel is dried to 900℃ to 920℃ before starting rolling, with a reduction of 25mm to 35mm per pass, and high-pressure water cooling is performed multiple times during the rolling process; In the third stage, the steel thickness is H + (40 to 70) mm, the starting rolling temperature is 800℃ to 820℃, and the final rolling temperature is ≥750℃; After rolling, the steel plate enters ACC cooling, and the red-hot temperature is controlled below 600℃.
2. The rolling method for Ni-added steel plates for nuclear power projects according to claim 1, characterized in that, Before heating, the continuously cast billet is wrapped with carbon steel sheet.
3. The rolling method for Ni-added steel plates for nuclear power projects according to claim 2, characterized in that, The thickness of the carbon steel sheet is 1mm to 2mm.
4. The rolling method for Ni-added steel plates for nuclear power projects according to claim 1, characterized in that, The chemical composition of the steel plate is as follows: C: 0.10%~0.12%, Si: 0.15%~0.30%, Mn: 1.50%~1.60%, P≤0.010, S≤0.005%, Ni: 0.80%~0.90%, V: 0.020~0.030, with the remainder being Fe and unavoidable impurities.
5. A rolling method for Ni-added steel plates for nuclear power projects according to claim 1, characterized in that, The thickness of the steel plate is 10mm to 60mm.
6. The rolling method for Ni-added steel plates for nuclear power projects according to claim 1, characterized in that, The steel plate, after quenching and tempering heat treatment, has a smooth surface free of loose iron oxide scale; its mechanical properties are as follows: yield strength R p0.2 ≥420MPa, tensile strength R m 570MPa~720MPa, elongation after fracture A≥20%; impact energy at 1 / 2 thickness at -60℃ KV2≥47J.