Method for manufacturing nickel-chromium electrothermal alloy continuous casting slab

Abstract

This invention discloses a method for manufacturing a nickel-chromium electrothermal alloy continuous casting slab, comprising: steel smelting, using electric furnace smelting + AOD furnace smelting + LF furnace refining to obtain molten steel; ladle casting, ladle casting temperature 1460-1470℃; tundish casting, tundish molten steel temperature 1430-1450℃; continuous casting, with the following parameters: mold flux basicity 0.80-0.90, viscosity 1.3-1.6 poise, liquid-solid transition temperature 1020-1050℃, slag layer thickness 5-8mm, slag consumption 0.75-0.85Kg per ton of molten steel, mold taper 1.25-1.28% / m, slab casting speed 0.55±0.05m / min, mold wide-face to narrow-face heat flux ratio 1.0-1.05, inlet water temperature 32-34℃, and secondary cooling water flow density 43-45L / (min·m). 2 When the remaining molten steel in the tundish reaches 3-4 tons, the continuous casting is capped. This invention achieves stable production of nickel-chromium electrothermal alloy continuous casting slabs with a width of 1200-1250 mm, a thickness of 180-200 mm, and a weight greater than 10 tons through reasonable matching of key process parameters such as molten steel process temperature, casting speed, crystallizer, and secondary cooling zone, and reasonable selection of the physical properties of the protective slag used in the crystallizer. The surface quality of the continuously cast slabs is excellent.

Description

Technical Field

[0001] This invention belongs to the field of steelmaking and continuous casting technology, and specifically relates to a method for manufacturing a nickel-chromium electrothermal alloy continuous casting slab. Background Technology

[0002] According to their alloy system, electric heating alloys can be divided into ferritic iron-chromium-aluminum alloys and austenitic nickel-chromium alloys. Among them, nickel-chromium alloys have high Cr and Ni content, and have the advantages of high temperature strength, not easy to deform, good weldability, high temperature structural stability, and easy forming. They are widely used in the manufacturing of electric heating elements in industrial furnaces, petrochemicals, and household appliances.

[0003] Due to the compositional characteristics of nickel-chromium alloys, existing technologies primarily employ a small-scale smelting method using an induction furnace combined with electroslag remelting for smelting, forging, and rolling. This process suffers from low production efficiency, low yield, and significant performance fluctuations. Furthermore, nickel-chromium alloy strip products produced using this process have small coil weights and widths, resulting in very low yields and large fluctuations in the composition and properties of the entire coil.

[0004] Utilizing continuous casting technology for large-scale production of nickel-chromium alloy products offers high yields, but the technology is technically challenging. The difficulties in continuous casting of nickel-chromium alloy slabs include: the high alloy content of nickel-chromium alloys, resulting in poor thermal conductivity; the tendency for high-temperature grain growth due to their austenitic structure, leading to well-developed columnar crystals and high susceptibility to high-temperature cracking; and the addition of reactive elements such as Si, Al, Ti, and rare earth elements to improve performance. These elements readily react chemically with oxygen in the air, refractory materials, and continuous casting flux, causing problems such as nozzle blockage, deterioration of flux properties, slag coating on the slab surface, and surface cracks during production. These issues directly hinder the industrial production of nickel-chromium electric heating alloy plates. Summary of the Invention

[0005] To address some or all of the technical problems existing in the prior art, the present invention provides a method for manufacturing a nickel-chromium electrothermal alloy continuous casting slab, comprising the following steps:

[0006] S1. Steel smelting: Steel is produced by electric furnace smelting + AOD furnace smelting + LF furnace refining.

[0007] S2. Pouring with the large ladle: The pouring temperature of the large ladle is controlled at 1460-1470℃, and the connection between the long spout and the large ladle is sealed with argon gas.

[0008] S3, Tundish Casting: Molten steel in the tundish is introduced into the crystallizer through an immersion nozzle. The nozzle insertion depth is controlled at 120±3mm, and the molten steel temperature in the tundish is controlled at 1430~1450℃.

[0009] S4. Continuous Casting: The basicity R = CaO / SiO2 of the mold flux is controlled at 0.80–0.90; the viscosity of the mold flux (at 1300℃) is controlled at 1.3–1.6 poise; the liquid-solid transition temperature of the mold flux is controlled at 1020–1050℃; the thickness of the liquid slag layer in the mold is controlled at 5–8 mm; the slag consumption is controlled at 0.75–0.85 kg per ton of molten steel; the taper of the mold is controlled at 1.25–1.28% / m; the billet casting speed is controlled at 0.55 ± 0.05 m / min; the ratio of the average heat flux intensity of the wide-face copper plate to the average heat flux intensity of the narrow-face copper plate in the mold is controlled at 1.0–1.05; the inlet water temperature is controlled at 32–34℃; and the flow density of the secondary cooling water is controlled at 43–45 L / (min·m). 2 When there are 3 to 4 tons of molten steel remaining in the tundish, the continuous casting is capped.

[0010] Furthermore, in the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, the chemical composition of the molten steel obtained by smelting is controlled by mass percentage as follows: C: 0.02~0.05%, Si: 1.00~3.00%, Mn≤1.00%, P≤0.020%, S≤0.010%, Cr: 18.00~21.00%, Ni: 30.00~34.00%, Cu≤0.50%, with the remainder being Fe and unavoidable impurities.

[0011] Furthermore, in the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, the molten steel obtained by smelting also contains Al: 0.15-0.30%, Ti: 0.10-0.20%, and N≤0.008% by mass percentage.

[0012] Furthermore, in the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, during the continuous casting step, the average heat flux intensity of the wide copper plate in the crystallizer is controlled at 1.13–1.17 mW / m. 2 The average heat flux intensity of the narrow copper plate in the crystallizer is controlled at 1.09–1.13 mW / m. 2 .

[0013] Furthermore, in the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, argon blowing protection is carried out throughout the continuous casting process.

[0014] As one specific implementation method, the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs is used to prepare nickel-chromium electrothermal alloy continuous casting slabs with a width of 1200-1250 mm, a thickness of 180-200 mm, and a weight of more than 10 tons.

[0015] The method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs of the present invention has the following advantages and beneficial effects:

[0016] This invention achieves good surface quality for nickel-chromium electrothermal alloy continuous casting slabs by rationally matching key process parameters such as steel temperature, casting speed, crystallizer, and secondary cooling zone, and by rationally selecting the physical properties of the protective slag used in the crystallizer. The slabs are free from defects such as surface cracks and slag inclusions. The nickel-chromium electrothermal alloy plates produced using these slabs as raw materials have good surface quality, free from defects such as slag inclusions and longitudinal cracks, and their resistivity meets the standard requirements.

[0017] This invention enables the stable production of nickel-chromium electrothermal alloy continuous casting slabs with a width of 1200-1250 mm, a thickness of 180-200 mm, and a weight of more than 10 tons using a continuous casting process. This significantly increases the single coil weight of nickel-chromium electrothermal alloy strips and improves the uniformity of material composition and properties.

[0018] This invention significantly improves product yield and production efficiency, reduces production costs, and greatly enhances product composition and performance stability, thus powerfully promoting the industrial production of nickel-chromium electrothermal alloy sheet products. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] To address the problems of surface cracking and slag encapsulation in the current manufacturing process of nickel-chromium alloy continuous casting slabs, the inventors conducted in-depth research on alloy properties, optimized the design of protective slag parameters for the crystallizer, and developed a manufacturing method for nickel-chromium electrothermal alloy continuous casting slabs by rationally matching key process parameters such as molten steel temperature, casting speed, crystallizer, and secondary cooling zone. This method enables stable production of nickel-chromium alloy continuous casting slabs with good surface quality and significantly improved product composition and performance stability.

[0021] Specifically, the method for manufacturing a nickel-chromium electrothermal alloy continuous casting slab of the present invention includes the following steps:

[0022] S1. Steel smelting: The process involves electric furnace smelting + argon-oxygen decarburization furnace (AOD furnace) smelting + ladle refining furnace (LF furnace) refining to produce molten steel that meets the standard requirements.

[0023] S2, pour the water in large batches;

[0024] S3, pouring begins with the intermediate pouring;

[0025] S4, continuous casting.

[0026] Furthermore, in the steel smelting step of the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, the chemical composition of the molten steel obtained by smelting is controlled by mass percentage as follows: C: 0.02~0.05%, Si: 1.00~3.00%, Mn≤1.00%, P≤0.020%, S≤0.010%, Cr: 18.00~21.00%, Ni: 30.00~34.00%, Cu≤0.50%, with the remainder being Fe and unavoidable impurities.

[0027] Furthermore, to ensure the performance of the nickel-chromium electric heating alloy sheet products and improve their high-temperature plasticity, in the steel smelting step of the above-mentioned method for manufacturing nickel-chromium electric heating alloy continuous casting slabs, the molten steel obtained by smelting also contains, by mass percentage: Al: 0.15–0.30%, Ti: 0.10–0.20%, and N ≤ 0.008%. The functions of the above chemical elements are as follows:

[0028] Al: Al is a beneficial alloying element added to this nickel-chromium alloy. As a strong deoxidizing element, Al can further improve the purity of the steel, which is beneficial for improving the surface quality and service life of nickel-chromium electric heating alloy plates. Simultaneously, Al₂O₃ makes the alloy oxide film denser, which also helps improve the alloy's resistance to high-temperature oxidation. However, during continuous casting, Al reacts with SiO₂ in the protective slag, forming Al₂O₃, which increases the viscosity of the protective slag, lowers the liquid-solid phase transition temperature, and deteriorates the lubrication and heat transfer performance of the protective slag. Therefore, in this invention, the Al content in the molten steel is limited to the range of 0.15% to 0.30%.

[0029] Ti: Ti is a beneficial alloying element added to this nickel-chromium alloy. Ti can refine the grain size and improve the resistivity of the alloy. However, during continuous casting, Ti easily reacts with SiO2 in the protective slag, resulting in the precipitation of a large amount of perovskite crystals in the slag. This significantly increases the viscosity of the protective slag, affecting slag consumption and slag uniformity, thereby reducing lubrication and heat transfer effects. In addition, excessive Ti can also cause more surface quality problems in the product. Therefore, in this invention, the Ti content in the molten steel is controlled within the range of 0.10% to 0.20%.

[0030] Nitrogen (N): Nitrogen is an impurity element that reacts with Al and Ti in steel during solidification to form AlN and TiN compounds, reducing the steel's machinability and performance. Therefore, in this invention, the N content in the molten steel is limited to no more than 0.080%.

[0031] Furthermore, in the ladle opening pouring step of the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, the ladle opening pouring temperature is controlled at 1460-1470℃, and the connection between the long nozzle and the ladle is sealed with argon gas.

[0032] Furthermore, in the tundish casting step of the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, the molten steel in the tundish is introduced into the crystallizer through an immersion nozzle, with the nozzle insertion depth controlled at 120±3mm. Based on the liquidus temperature of the nickel-chromium electrothermal alloy, the temperature of the molten steel in the tundish is controlled at 1430~1450℃.

[0033] Furthermore, during the casting process, the Al and Ti elements in the molten steel in the crystallizer react chemically with the protective slag, deteriorating the key performance indicators of the protective slag such as melting point and viscosity, leading to defects such as slag curling and cracks in the cast billet. Therefore, in the continuous casting step of the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, a special protective slag was developed for nickel-chromium electrothermal alloy continuous casting. The basicity R=CaO / SiO2 of the crystallizer protective slag is controlled at 0.80~0.90, the viscosity (1300℃) of the crystallizer protective slag is controlled at 1.3~1.6 poise, and the liquid-solid phase transition temperature of the crystallizer protective slag is controlled at 1020~1050℃. This can significantly reduce slag streaks and agglomeration, enabling smooth continuous casting and improving the surface quality of the cast billet.

[0034] Furthermore, in the continuous casting step of the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, the thickness of the liquid slag layer in the crystallizer is controlled at 5-8 mm, and the slag consumption is controlled at 0.75-0.85 kg per ton of molten steel.

[0035] Furthermore, since the taper of the crystallizer is crucial for heat transfer in molten steel and billet shell growth, it should be properly controlled: if the taper is too small, the billet shell will detach from the copper wall of the crystallizer prematurely, reducing the cooling effect and easily causing bulging, cracks, or even steel leakage when the billet exits the crystallizer; if the taper is too large, it will increase the resistance during billet pulling, accelerate crystallizer wear, and may also cause cracks or steel leakage accidents. Therefore, in the continuous casting step of the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, based on the solidification shrinkage characteristics of nickel-chromium alloys, the crystallizer taper is controlled at 1.25–1.28% / m.

[0036] Furthermore, in the continuous casting step of the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, the slab casting speed is controlled at 0.55±0.05 m / min, and the average heat flux intensity of the wide copper plate of the crystallizer is controlled at 1.13~1.17 mW / m. 2 (mW / m²), the average heat flux intensity of the narrow copper plate of the crystallizer is controlled at 1.09–1.13 mW / m². 2 (milliwatts per square meter), the inlet water temperature is controlled at 32-34℃, and the heat flux ratio of the wide face to the narrow face is controlled at 1.0-1.05.

[0037] Furthermore, due to the high susceptibility of nickel-chromium alloys to high-temperature cracking and their poor high-temperature thermoplasticity, in the continuous casting step of the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, a weak cooling method is used in the secondary cooling zone, and the water flow density of the secondary cooling water is controlled at 43-45 L / (min·m). 2 This method avoids excessive cooling rate, which can lead to intergranular cracks. When there are 3 to 4 tons of molten steel remaining in the tundish, continuous casting is used to seal the top.

[0038] Furthermore, in the continuous casting step of the above-mentioned method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs, the molten steel pouring process is protected by argon blowing throughout.

[0039] Therefore, by reasonably matching the process parameters such as the cooling parameters of the crystallizer, the process temperature of the molten steel, and the casting speed as described above, the cooling rate of the molten steel in the crystallizer can be reduced, the sensitivity of the billet shell to high-temperature cracking can be reduced, a billet shell with uniform thickness can be obtained, and the tensile stress resistance of the nickel-chromium electrothermal alloy billet can be improved.

[0040] As one specific embodiment, the method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs of the present invention is used to prepare nickel-chromium electrothermal alloy continuous casting slabs with a width of 1200-1250 mm, a thickness of 180-200 mm, and a weight of more than 10 tons.

[0041] The following detailed description of the specific implementation of the method for manufacturing the nickel-chromium electrothermal alloy continuous casting slab of the present invention, with reference to the embodiments, is provided. However, the specific implementation of the present invention is not limited to the following embodiments.

[0042] Example 1

[0043] The manufacturing method of the nickel-chromium electrothermal alloy continuous casting slab in Example 1 includes the following steps:

[0044] S11. Steelmaking: The process involves electric arc furnace smelting + AOD furnace smelting + LF furnace refining to produce molten steel that meets the standard requirements. The chemical composition of the molten steel, by mass percentage, is as follows: C: 0.03%, Si: 1.50%, Mn: 0.53%, P: 0.015%, S: 0.010%, Cr: 19.56%, Ni: 32.37%, Al: 0.25%, Ti: 0.17%, Cu: 0.35%, N: 0.007%, with the remainder being Fe and unavoidable impurities.

[0045] S12. Pouring with the large ladle: The pouring temperature of the large ladle is controlled at 1460-1470℃, and the connection between the long spout and the large ladle is sealed with argon gas.

[0046] S13, Tundish Casting: Molten steel in the tundish is introduced into the crystallizer through an immersion nozzle. The nozzle insertion depth is controlled at 120±3mm. Based on the liquidus temperature of the nickel-chromium electrothermal alloy, the temperature of the molten steel in the tundish is controlled at 1430~1450℃.

[0047] S14. Continuous Casting: The basicity R = CaO / SiO2 of the mold flux used in the continuous casting process is 0.86, the viscosity (1300℃) is 1.47 poise, the liquid-solid transition temperature is 1035℃, the thickness of the liquid slag layer in the mold is controlled at 5-8 mm, and the slag consumption is controlled at 0.78 kg per ton of molten steel; the taper of the mold is controlled at 1.25% / m, the billet casting speed is controlled at 0.55 m / min, and the average heat flux intensity of the wide copper plate of the mold is controlled at 1.14 mW / m. 2 The average heat flux intensity of the narrow copper plate in the crystallizer was controlled at 1.11 mW / m. 2 The inlet water temperature is controlled at 32–34℃, and the heat flux ratio between the wide and narrow sides is controlled at 1.03; the flow density of the secondary cooling water is 43.5 L / (min·m). 2 When the tundish has 3.3 tons of molten steel remaining, the continuous casting is capped.

[0048] Using the manufacturing method of nickel-chromium electrothermal alloy continuous casting slab in Example 1, a nickel-chromium electrothermal alloy continuous casting slab with a width of 1250 mm, a thickness of 200 mm, and a weight of 13.9 tons was produced. The continuous casting slab production process was normal, and there were no visible inclusions or heavy scale defects on the surface of the continuous casting slab after rolling into steel coils.

[0049] Example 2

[0050] The manufacturing method of the nickel-chromium electrothermal alloy continuous casting slab in Example 2 includes the following steps:

[0051] S21. Steelmaking: The process involves electric arc furnace smelting + AOD furnace smelting + LF furnace refining to produce molten steel that meets the standard requirements. The chemical composition of the molten steel, by mass percentage, is as follows: C: 0.04%, Si: 1.82%, Mn: 0.55%, P: 0.017%, S: 0.002%, Cr: 20.36%, Ni: 33.5%, Al: 0.28%, Ti: 0.15%, Cu: 0.45%, N: 0.0065%, with the remainder being Fe and unavoidable impurities.

[0052] S22. Ladle pouring: The ladle pouring temperature is controlled at 1460-1470℃, and the connection between the long spout and the ladle is sealed with argon gas.

[0053] S23, Tundish Casting: Molten steel in the tundish is introduced into the crystallizer through an immersion nozzle. The nozzle insertion depth is controlled at 120±3mm. Based on the liquidus temperature of the nickel-chromium electrothermal alloy, the temperature of the molten steel in the tundish is controlled at 1440~1450℃.

[0054] S24. Continuous Casting: The basicity R = CaO / SiO2 of the mold flux used in the continuous casting process is 0.88, the viscosity (1300℃) is 1.52 poise, the liquid-solid transition temperature is 1043℃, the thickness of the liquid slag layer in the mold is controlled at 5-8 mm, and the slag consumption is controlled at 0.75 kg per ton of molten steel; the taper of the mold is controlled at 1.25% / m, the billet casting speed is controlled at 0.60 m / min, and the average heat flux intensity of the wide copper plate of the mold is controlled at 1.16 mW / m. 2 The average heat flux intensity of the narrow copper plate in the crystallizer was controlled at 1.12 mW / m. 2 The inlet water temperature is controlled at 32–34℃, and the heat flux ratio between the wide and narrow sides is controlled at 1.04; the flow density of the secondary cooling water is 44.7 L / (min·m). 2 When 4 tons of molten steel remained in the tundish, the continuous casting was capped.

[0055] Using the manufacturing method of nickel-chromium electrothermal alloy continuous casting slab in Example 2, a nickel-chromium electrothermal alloy continuous casting slab with a width of 1200 mm, a thickness of 180 mm, and a weight of 13.6 tons was produced. The continuous casting slab production process was normal, and the surface quality of the continuous casting slab after rolling into steel coils was good.

[0056] Example 3

[0057] The manufacturing method of the nickel-chromium electrothermal alloy continuous casting slab in Example 3 includes the following steps:

[0058] S31. Steelmaking: The process involves electric arc furnace smelting + AOD furnace smelting + LF furnace refining to produce molten steel that meets the standard requirements. The chemical composition of the molten steel, by mass percentage, is as follows: C: 0.045%, Si: 2.50%, Mn: 0.52%, P: 0.013%, S: 0.001%, Cr: 20.57%, Ni: 32.8%, Al: 0.25%, Ti: 0.17%, Cu: 0.22%, N: 0.0058%, with the remainder being Fe and unavoidable impurities.

[0059] S32. Ladle pouring: The ladle pouring temperature is controlled at 1460-1470℃, and the connection between the long spout and the ladle is sealed with argon gas.

[0060] S33, Tundish Casting: Molten steel in the tundish is introduced into the crystallizer through an immersion nozzle. The nozzle insertion depth is controlled at 120±3mm. Based on the liquidus temperature of the nickel-chromium electrothermal alloy, the temperature of the molten steel in the tundish is controlled at 1435~1450℃.

[0061] S34. Continuous Casting: The basicity R = CaO / SiO2 of the mold flux used in the continuous casting process is 0.83, the viscosity (1300℃) is 1.55 poise, the liquid-solid transition temperature is 1040℃, the thickness of the liquid slag layer in the mold is controlled at 5-8 mm, and the slag consumption is controlled at 0.78 kg per ton of molten steel; the taper of the mold is controlled at 1.26% / m, the billet casting speed is controlled at 0.60 m / min, and the average heat flux intensity of the wide copper plate of the mold is controlled at 1.17 mW / m. 2 The average heat flux intensity of the narrow copper plate in the crystallizer was controlled at 1.11 mW / m. 2 The inlet water temperature is controlled at 32–34℃, and the heat flux ratio between the wide and narrow sides is controlled at 1.05; the flow density of the secondary cooling water is 44.3 L / (min·m). 2 When the molten steel remaining in the tundish reached 3.8 tons, the continuous casting was capped.

[0062] Using the manufacturing method of nickel-chromium electrothermal alloy continuous casting slab in Example 3, a nickel-chromium electrothermal alloy continuous casting slab with a width of 1240 mm, a thickness of 180 mm, and a weight of 12.8 tons was produced. The continuous casting slab production process was normal, and the surface quality of the continuous casting slab after rolling into steel coils was good.

[0063] In summary, the method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs of the present invention involves obtaining molten steel through electric furnace smelting + AOD furnace smelting + LF furnace refining, and then casting the molten steel into nickel-chromium electrothermal alloy continuous casting slabs via ladle casting and tundish casting. This method can stably produce nickel-chromium electrothermal alloy continuous casting slabs with a width of 1200–1250 mm, a thickness of 180–200 mm, and a weight greater than 10 tons. Compared with the prior art, the method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs of the present invention has the following advantages and beneficial effects:

[0064] (1) By reasonably matching key process parameters such as steel process temperature, casting speed, crystallizer and secondary cooling zone, and reasonably selecting the physical property parameters of protective slag for crystallizer, the surface quality of nickel-chromium electric heating alloy continuous casting slab is good, with no surface cracks, slag inclusions and other defects. The surface quality of nickel-chromium electric heating alloy plate products produced using this continuous casting slab as raw material is good, with no slag inclusions, longitudinal cracks and other defects on the surface, and the resistivity meets the standard requirements.

[0065] (2) The continuous casting process has been able to stably produce nickel-chromium electrothermal alloy continuous casting slabs with a width of 1200-1250 mm, a thickness of 180-200 mm, and a weight of more than 10 tons. This can significantly increase the single coil weight of nickel-chromium electrothermal alloy strips and improve the uniformity of material composition and performance.

[0066] (3) It has greatly improved the product yield and production efficiency, reduced production costs, and significantly improved the stability of product composition and performance, which has powerfully promoted the industrial production of nickel-chromium electric heating alloy plate products.

[0067] It should be noted that, in this document, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing a nickel-chromium electrothermal alloy continuous casting slab, characterized in that, The steps include the following: S1. Steel smelting: Steel is produced by electric furnace smelting + AOD furnace smelting + LF furnace refining. S2. Pouring with the large ladle: The pouring temperature of the large ladle is controlled at 1460~1470℃, and the connection between the long spout and the large ladle is sealed with argon gas. S3, Tundish Casting: Molten steel from the tundish is introduced into the crystallizer through an immersion nozzle. The nozzle insertion depth is controlled at 120±3mm, and the molten steel temperature in the tundish is controlled at 1430~1450℃. S4. Continuous Casting: The basicity R=CaO / SiO2 of the mold flux is controlled at 0.80~0.90; the viscosity of the mold flux at 1300℃ is controlled at 1.3~1.6 poise; the liquid-solid transition temperature of the mold flux is controlled at 1020~1050℃; the thickness of the liquid slag layer in the mold is controlled at 5~8mm; the slag consumption is controlled at 0.75~0.85Kg per ton of molten steel; the taper of the mold is controlled at 1.25~1.28% / m; the billet casting speed is controlled at 0.55±0.05m / min; the ratio of the average heat flux intensity of the wide copper plate to the average heat flux intensity of the narrow copper plate in the mold is controlled at 1.0~1.05; the inlet water temperature is controlled at 32~34℃; and the flow density of the secondary cooling water is controlled at 43~45L / (min·m). 2 When there are 3-4 tons of molten steel remaining in the tundish, the continuous casting is capped.

2. The method for manufacturing a nickel-chromium electrothermal alloy continuous casting slab as described in claim 1, characterized in that, The chemical composition of the molten steel obtained by smelting is controlled by mass percentage as follows: C: 0.02~0.05%, Si: 1.00~3.00%, Mn≤1.00%, P≤0.020%, S≤0.010%, Cr: 18.00~21.00%, Ni: 30.00~34.00%, Cu≤0.50%, with the remainder being Fe and unavoidable impurities.

3. The method for manufacturing a nickel-chromium electrothermal alloy continuous casting slab as described in claim 2, characterized in that, The molten steel obtained from smelting also contains Al: 0.15~0.30%, Ti: 0.10~0.20%, and N≤0.008% by mass percentage.

4. The method for manufacturing a nickel-chromium electrothermal alloy continuous casting slab as described in claim 1, characterized in that, During the continuous casting process, the average heat flux intensity of the wide copper plate in the crystallizer is controlled at 1.13~1.17 mW / m. 2 The average heat flux intensity of the narrow copper plate in the crystallizer is controlled at 1.09~1.13 mW / m. 2 .

5. The method for manufacturing a nickel-chromium electrothermal alloy continuous casting slab as described in claim 1, characterized in that, During the continuous casting process, argon blowing is used for protection throughout the entire steel pouring process.

6. The method for manufacturing a nickel-chromium electrothermal alloy continuous casting slab as described in any one of claims 1 to 5, characterized in that, The method for manufacturing nickel-chromium electrothermal alloy continuous casting slabs is used to prepare nickel-chromium electrothermal alloy continuous casting slabs with a width of 1200~1250mm, a thickness of 180~200mm, and a weight of more than 10 tons.