Method for reducing silicon dioxide on surface of crystallization roller for thin-strip continuous casting non-oriented silicon steel

Abstract

The invention belongs to the technical field of metallurgical engineering, and particularly relates to a method for reducing silicon dioxide on the surface of a crystallization roller for thin-strip continuous casting non-oriented silicon steel. According to the invention, the rare earth type, the addition amount and the proportion are optimized under the synergistic effect of the preparation process; and the content of silicon dioxide in a film deposited on the surface of the crystallization roller is reduced as much as possible while the wetting angle between the molten steel and the crystallization roller is reduced. The key technical support is provided for efficient and stable thin-strip continuous casting production of the high-silicon non-oriented silicon steel. Through cooperative regulation and control, the interface heat transfer of the non-oriented silicon steel is enhanced, and the surface quality is improved. The problems that the high-silicon non-oriented silicon steel is poor in heat transfer performance and poor in castability are effectively solved, and a brand new way is provided for achieving stable casting and obtaining excellent surface quality of the high-silicon non-oriented silicon steel.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical engineering technology, and specifically relates to a method for reducing silica on the surface of crystallizing rolls used in thin strip continuous casting of non-oriented silicon steel. Background Technology

[0002] Non-oriented silicon steel, as a core soft magnetic material in power equipment such as motors and generators, directly determines the energy efficiency of these devices due to its magnetic properties. Research shows that increasing the silicon content is the most effective way to reduce iron losses and improve magnetic performance, especially under high-frequency operating conditions, where the high resistivity resulting from high silicon content can significantly suppress eddy current losses. Therefore, for high-end applications such as high-efficiency motors and drive motors for new energy vehicles, non-oriented silicon steel will inevitably develop towards higher silicon content.

[0003] However, while increasing silicon content optimizes magnetic properties, it also presents significant challenges to the thin-strip continuous casting process. When the silicon content enters a high-silicon system (>3.0%), the physicochemical properties of silicon steel also change significantly. First, the viscosity of the molten steel increases, leading to a substantial decrease in wettability. Second, the thermal conductivity of silicon steel decreases significantly, slowing down the solidification rate and limiting the increase in casting speed and production efficiency. Third, high-silicon steel lacks austenitic phase transformation during solidification, failing to compensate for volume shrinkage and exacerbating the tendency for air gap formation. The combined effect of these factors results in excessively high silica content in the deposited film on the surface of the crystallizing roll during twin-roll thin-strip continuous casting of high-silicon non-oriented silicon steel, hindered interfacial heat transfer, poor solidification uniformity, and deterioration of the surface quality of the cast strip, making it difficult to achieve stable and efficient production.

[0004] In contrast, while medium-silicon non-oriented silicon steel possesses a certain degree of castability, its magnetic properties are insufficient to meet the demands of high-end applications. Further improvements to the interfacial behavior of the molten steel could help optimize its surface quality. However, in high-silicon systems, the poor wettability, slow heat transfer, and numerous air gaps create a complex problem, making stable casting of the molten steel difficult, limiting production efficiency, and hindering surface quality control. These issues constitute a technological bottleneck restricting the industrial application of high-silicon non-oriented silicon steel in thin strip continuous casting.

[0005] To address the aforementioned interface issues, research indicates that the naturally formed oxide deposit film (mainly composed of oxides of elements such as O, Fe, Si, and Mn) on the surface of the crystallizing roll can influence interfacial heat transfer behavior to some extent. A deposit film of appropriate thickness can fill microscopic air gaps, improve interfacial contact, and provide a certain degree of lubrication. However, the composition, thickness, and distribution of this deposit film are influenced by both the steel melt composition and process parameters, making control quite challenging.

[0006] Rare earth elements, due to their unique electronic structure and surface activity, show significant potential in regulating the interfacial behavior of molten metals. Their large atomic radii and low electronegativity facilitate adsorption at interfaces and alter interfacial energy states, effectively reducing the surface and interfacial tension of molten steel. They have already been widely used in the preparation of non-oriented silicon steel. For example, patents CN120818740A, CN117904394A, and CN119876733A all involve introducing rare earth elements into non-oriented silicon steel; however, to date, there are few records of using rare earth element proportions in conjunction with thin-strip continuous casting process parameters to reduce silica on the surface of the crystallizing rolls. Summary of the Invention

[0007] This invention addresses the shortcomings of existing technologies by proposing for the first time to reduce the silica content on the surface of the crystallizing rollers by selecting the proportion of rare earth elements in conjunction with the thin strip continuous casting process parameters.

[0008] This invention effectively improves interfacial heat transfer during continuous casting by reducing the silica content in the naturally deposited film on the surface of the crystallizing roll, resulting in a significant increase in peak heat flux density and total heat conduction within the first 2 seconds. Furthermore, the process employed in this invention yields non-oriented silicon steel cast strips with excellent surface quality.

[0009] The technical solution of the present invention is as follows:

[0010] A method for reducing silica on the surface of crystallizing rolls used in thin strip continuous casting of non-oriented silicon steel includes the following steps:

[0011] S1. Adjust the molten steel for smelting non-oriented silicon steel, and adjust and control the chemical composition of the molten steel by mass percentage as follows: C ≤ 0.003%, Si: 2.5 ~ 3.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, mixed rare earth: 0.015% ~ 0.15%, with the balance being Fe and unavoidable impurities;

[0012] S2. The molten steel obtained in step S1 is injected into a twin-roll thin strip continuous casting equipment, where it contacts the rotating crystallizing rolls to form a molten pool; at a cooling rate of 10... 2 ~ 10 4 Casting is carried out under sub-rapid solidification conditions of ℃ / s to obtain the casting strip; the casting temperature is controlled at a superheat of 50~95℃, Ar gas is used as the protective atmosphere throughout the process, water is used as the cooling medium, the casting roll material is copper, the roll gap is 1.8~2.0 mm, and the casting speed is 0.6~0.7 m / s.

[0013] S3. After step S2, a natural deposition film is formed on the surface of the crystallizing roller during the cooling process of the molten steel.

[0014] In this invention, in step S1, the mixed rare earth elements are selected from at least two of La, Ce, Y, and Sc. Preferably, they are La and Ce.

[0015] As a preferred embodiment A, the present invention provides a method for reducing silica on the surface of crystallizing rolls used in thin strip continuous casting of non-oriented silicon steel, comprising the following steps:

[0016] S1. Adjust the molten steel for smelting non-oriented silicon steel, and adjust and control the chemical composition of the molten steel by mass percentage as follows: C ≤ 0.003%, Si: 2.5 ~ 2.8%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, mixed rare earth: 0.015% ~ 0.02%, with the balance being Fe and unavoidable impurities; the mixed rare earth is composed of La and Ce in a molar ratio of 1:2~2.3;

[0017] S2. The molten steel obtained in step S1 is injected into a twin-roll thin strip continuous casting equipment, where it contacts the rotating crystallizing rolls to form a molten pool; at a cooling rate of 10... 2 ~ 10 4 Casting is carried out under sub-rapid solidification conditions of ℃ / s to obtain the casting strip; the casting temperature is controlled at a superheat of 50~55℃, Ar gas is used as the protective atmosphere throughout the process, water is used as the cooling medium, the casting roll material is copper, the roll gap is 1.8~2.0 mm, and the casting speed is 0.6~0.7 m / s.

[0018] In preferred embodiment A, the SiO2 content in the deposited film on the surface of the crystallizing roller is reduced to 28.9~29 wt.%.

[0019] As a preferred embodiment B, the present invention provides a method for reducing silica on the surface of crystallizing rolls used in thin strip continuous casting of non-oriented silicon steel, comprising the following steps:

[0020] S1. Non-oriented silicon steel is smelted using a vacuum induction furnace, and the chemical composition of the molten steel is controlled as follows (mass percentage): C ≤ 0.003%, Si: 3.2~3.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, mixed rare earth: 0.015%~0.02%, with the balance being Fe and unavoidable impurities; the mixed rare earth is composed of La and Ce in a molar ratio of 1:1~1.2.

[0021] S2. Heat the molten steel to a superheat of 85~90℃ and pour it into a twin-roll thin strip continuous casting equipment for casting. The casting rolls are made of copper, the roll gap is 1.8~2.0 mm, and the casting speed is 0.7 m / s.

[0022] In preferred embodiment B, the SiO2 content in the crystallization roller deposited film is reduced to 29.2~29.35 wt.%.

[0023] In step S2, real-time temperature data is obtained using thermocouples embedded at different positions on the crystallizing roller. The instantaneous interfacial heat flux density during the solidification process is calculated using a back-calculation heat conduction program. Beck's nonlinear estimation method is then used to solve the one-dimensional heat transfer inverse problem algorithm model.

[0024] In step S2, the interfacial tension between the molten steel and the crystallizing roll is calculated according to Young's equation and a simplified Laplace formula based on the shape factor β, wherein the shape factor β is determined by the droplet profile parameter.

[0025] The deposition film on the surface of the crystallizing roller is a naturally deposited film obtained after seven repeated experiments.

[0026] Compared with the prior art, the features and beneficial effects of the present invention are as follows:

[0027] This invention optimizes the types, amounts, and proportions of rare earth elements, and through the synergistic effect of the preparation process, reduces the wetting angle between the molten steel and the crystallizing roll while minimizing the silica content in the deposited film on the crystallizing roll surface. This provides key technical support for the efficient and stable thin-strip continuous casting production of high-silicon non-oriented silicon steel. Attached Figure Description

[0028] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. The drawings are for illustrative purposes only and are not intended to limit the present invention.

[0029] Figure 1 This is a comparison diagram of the interfacial wetting angle between molten steel and crystallizing roller in the embodiments and comparative examples of the present invention;

[0030] Figure 2 This is a comparison diagram of the thickness of naturally deposited films in the embodiments and comparative examples of the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] The examples were conducted under an argon atmosphere. Thermocouples were embedded at different locations on the crystallizing roller for temperature measurement, and the instantaneous interfacial heat flux density was calculated using a back-calculation heat conduction program. A CCD camera was used to record the steel sample dripping and solidification process, and the interfacial contact angle between the molten steel and the crystallizing roller was calculated using Image-J software. The morphology and chemical composition of the naturally deposited film were observed and determined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).

[0033] Example 1

[0034] In this embodiment, rare earth regulation of silicon-free silicon steel is carried out based on the following steps:

[0035] S1. Non-oriented silicon steel is smelted using a vacuum induction furnace, and the chemical composition of the molten steel is controlled as follows (mass percentage): C ≤ 0.003%, Si: 2.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, La: 0.015%, with the balance being Fe and unavoidable impurities.

[0036] S2. The molten steel is heated to a superheat of approximately 50°C and poured into a twin-roll thin strip continuous casting equipment for casting. The casting rolls are made of copper, with a roll gap of 1.8~2.0 mm, and a casting speed of 0.7 m / s. The measured wetting angle between the molten steel and the crystallizing roll is 115°.

[0037] S3. Maintain a constant cooling water temperature, measure the real-time temperature of the molten steel after contact with the crystallizing roll, and calculate the interfacial heat flux density. The peak heat flux density is 8.7 MW / m³. 2 The total heat conduction within the initial 2 seconds is 5.9 MJ / m. 2 .

[0038] After repeating the experiment 3 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 112°; after repeating the experiment 5 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 110°; after repeating the experiment 7 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 109°; after repeating the experiment 9 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 108°.

[0039] After repeating the experiment 7 times, the composition of the naturally deposited film on the crystallizing roller was 30.92 wt.% SiO2~41.47 wt.% MnO~27.61 wt.% FeO.

[0040] Example 2

[0041] In this embodiment, rare earth regulation of silicon-free silicon steel is carried out based on the following steps:

[0042] S1. Non-oriented silicon steel is smelted using a vacuum induction furnace, and the chemical composition of the molten steel is controlled as follows (mass percentage): C ≤ 0.003%, Si: 2.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, La: 0.15%, with the balance being Fe and unavoidable impurities.

[0043] S2. Heat the molten steel to a superheat of approximately 50°C and pour it into a twin-roll thin-strip continuous casting equipment for casting. The casting rolls are made of copper, with a roll gap of 1.8~2.0 mm, and a casting speed of 0.7 m / s. Figure 1 As shown, the wetting angle between the molten steel and the crystallizing roll was measured to be 116°.

[0044] S3. Maintain a constant cooling water temperature, measure the real-time temperature of the molten steel after contact with the crystallizing roll, and calculate the interfacial heat flux density. The peak heat flux density is 5.6 MW / m³. 2 The total heat conduction within the initial 2 seconds is 3.9 MJ / m. 2 .

[0045] After repeating the experiment 3 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 112°; after repeating the experiment 5 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 110°; after repeating the experiment 7 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 109°; after repeating the experiment 9 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 109°.

[0046] After repeating the experiment 7 times, the composition of the naturally deposited film on the crystallizing roller was 29.48 wt.% SiO2~41.56 wt.% MnO~28.96 wt.% FeO, and the thickness of the deposited film reached 5.57 μm.

[0047] Example 3

[0048] In this embodiment, rare earth regulation of silicon-free silicon steel is carried out based on the following steps:

[0049] S1. Non-oriented silicon steel is smelted in a vacuum induction furnace, and the chemical composition of the molten steel is controlled as follows (mass percentage): C ≤ 0.003%, Si: 2.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, La+Ce: 0.015%, with the balance being Fe and unavoidable impurities (the molar ratio of La to Ce is 1:2.3).

[0050] S2. Heat the molten steel to a superheat of approximately 50°C and pour it into a twin-roll thin strip continuous casting machine for casting. The casting rolls are made of copper, with a roll gap of 1.8~2.0 mm, and a casting speed of 0.7 m / s. Figure 1As shown, the measured wetting angle between the molten steel and the crystallizing roll was 108°, which was 15.0% lower than that of Comparative Example 1, effectively improving the wettability between the molten steel and the crystallizing roll.

[0051] S3. Maintain a constant cooling water temperature, measure the real-time temperature of the molten steel after contact with the crystallizing roll, and calculate the interfacial heat flux density. The peak heat flux density is 9.9 MW / m³. 2 The total heat conduction within the initial 2 seconds is 8.6 MJ / m. 2 Compared to Comparative Example 1, the peak heat flux density increased by 29.1%, and the interfacial heat transfer was significantly enhanced.

[0052] After repeating the experiment 3 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 105°; after repeating the experiment 5 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 103°; after repeating the experiment 7 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 102°; after repeating the experiment 9 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 101°.

[0053] S4. After repeating the experiment multiple times, characterization methods were used to determine the thickness and composition of the naturally deposited film, and the melting point of the deposited film was calculated. Figure 2 The graph shows a comparison of the thickness of the naturally deposited films in the examples and comparative examples. It can be seen that the thicknesses of the naturally deposited films were 1.716 μm (3 times), 2.506 μm (5 times), 3.034 μm (7 times), and 3.635 μm (9 times), respectively. The average deposition rate of the naturally deposited films was 0.404 μm / cycle, which is 18.8% higher than that of Comparative Example 1. Furthermore, in terms of composition, after seven repetitions of the experiment, the composition of the naturally deposited films, in oxide form, was 28.98 wt.% SiO2 ~ 40.52 wt.% MnO ~ 30.50 wt.% FeO. Compared to Comparative Example 1, the proportion of SiO2 decreased by approximately 21.1%.

[0054] Core loss P of finished plate 10 / 50 The magnetic flux density is 0.9~1.2 W / Kg, and the magnetic induction intensity B 50 It has a strength of 1.62 T, a tensile strength of 486 MPa, a yield strength of 364 MPa, and an elongation of 30%.

[0055] Example 4

[0056] In this embodiment, rare earth-modified high-silicon non-oriented silicon steel is produced based on the following steps:

[0057] S1. Non-oriented silicon steel is smelted using a vacuum induction furnace, and the chemical composition of the molten steel is controlled as follows (mass percentage): C ≤ 0.003%, Si: 3.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, La: 0.015%, with the balance being Fe and unavoidable impurities.

[0058] S2. Heat the molten steel to a superheat of approximately 50°C and pour it into a twin-roll thin strip continuous casting machine for casting. The casting rolls are made of copper, with a roll gap of 1.8~2.0 mm, and a casting speed of 0.7 m / s. Figure 1 As shown, the wetting angle between the molten steel and the crystallizing roll was measured to be 118°.

[0059] S3. Maintain a constant cooling water temperature, measure the real-time temperature of the molten steel after contact with the crystallizing roll, and calculate the interfacial heat flux density. The peak heat flux density is 7.5 MW / m³. 2 The total heat conduction within the initial 2 seconds is 5.1 MJ / m. 2 .

[0060] After repeating the experiment 3 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 114°; after repeating the experiment 5 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 112°; after repeating the experiment 7 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 110°; after repeating the experiment 9 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 109°.

[0061] After repeating the experiment 7 times, the composition of the naturally deposited film on the crystallizing roller was 34.52 wt.% SiO2~43.25 wt.% MnO~22.23 wt.% FeO.

[0062] Example 5

[0063] In this embodiment, rare earth-modified high-silicon non-oriented silicon steel is produced based on the following steps:

[0064] S1. Non-oriented silicon steel is smelted using a vacuum induction furnace, and the chemical composition of the molten steel is controlled as follows (mass percentage): C ≤ 0.003%, Si: 3.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, La: 0.15%, with the balance being Fe and unavoidable impurities.

[0065] S2. Heat the molten steel to a superheat of approximately 50°C and pour it into a twin-roll thin strip continuous casting machine for casting. The casting rolls are made of copper, with a roll gap of 1.8~2.0 mm, and a casting speed of 0.7 m / s. Figure 1 As shown, the wetting angle between the molten steel and the crystallizing roll was measured to be 120°.

[0066] S3. Maintain a constant cooling water temperature, measure the real-time temperature of the molten steel after contact with the crystallizing roll, and calculate the interfacial heat flux density. The peak heat flux density is 4.3 MW / m³. 2 The total heat conduction within the initial 2 seconds is 3.1 MJ / m. 2 .

[0067] After repeating the experiment 3 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 116°; after repeating the experiment 5 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 115°; after repeating the experiment 7 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 114°; after repeating the experiment 9 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 114°.

[0068] After repeating the experiment 7 times, the composition of the naturally deposited film on the crystallizing roller was 32.49 wt.% SiO2~43.12 wt.% MnO~24.39 wt.% FeO, and the thickness of the deposited film reached 6.28 μm.

[0069] Example 6

[0070] In this embodiment, rare earth-modified high-silicon non-oriented silicon steel is produced based on the following steps:

[0071] S1. Non-oriented silicon steel is smelted using a vacuum induction furnace, and the chemical composition of the molten steel is controlled as follows (mass percentage): C ≤ 0.003%, Si: 3.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, La+Ce: 0.015%, with the balance being Fe and unavoidable impurities (the molar ratio of La to Ce is 1:1).

[0072] S2. Heat the molten steel to a superheat of approximately 50°C and pour it into a twin-roll thin strip continuous casting machine for casting. The casting rolls are made of copper, with a roll gap of 1.8~2.0 mm, and a casting speed of 0.7 m / s. Figure 1 As shown, the wetting angle between the molten steel and the crystallizing roll was measured to be 112°.

[0073] S3. Maintain a constant cooling water temperature, measure the real-time temperature of the molten steel after contact with the crystallizing roll, and calculate the interfacial heat flux density. The peak heat flux density is 8.0 MW / m³. 2 The total heat conduction within the initial 2 seconds is 5.8 MJ / m. 2 .

[0074] After repeating the experiment 3 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 109°; after repeating the experiment 5 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 106°; after repeating the experiment 7 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 105°; after repeating the experiment 9 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 104°.

[0075] S4. After repeating the experiment multiple times, the thickness and composition of the naturally deposited film were determined using characterization methods, and the melting point of the deposited film was calculated. In terms of composition, in oxide form, after repeating the experiment 7 times, the composition of the naturally deposited film was 33.12 wt.% SiO2~42.67 wt.% MnO~24.21 wt.% FeO.

[0076] Core loss P of finished plate 10 / 50 The magnetic flux density is 0.8~1.0 W / Kg, and the magnetic induction intensity B 50 It has a strength of 1.42 T, a tensile strength of 633 MPa, a yield strength of 475 MPa, and an elongation of 18%.

[0077] Example 7

[0078] In this embodiment, rare earth-modified high-silicon non-oriented silicon steel is produced based on the following steps:

[0079] S1. Non-oriented silicon steel is smelted using a vacuum induction furnace, and the chemical composition of the molten steel is controlled as follows (mass percentage): C ≤ 0.003%, Si: 3.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, La+Ce: 0.015%, with the balance being Fe and unavoidable impurities (the molar ratio of La to Ce is 1:1).

[0080] S2. Heat the molten steel to a superheat of approximately 90°C and pour it into a twin-roll thin-strip continuous casting equipment for casting. The casting rolls are made of copper, with a roll gap of 1.8~2.0 mm, and a casting speed of 0.7 m / s. Figure 1 As shown, the wetting angle between the molten steel and the crystallizing roll was measured to be 106°.

[0081] S3. Maintain a constant cooling water temperature, measure the real-time temperature of the molten steel after contact with the crystallizing roll, and calculate the interfacial heat flux density. The peak heat flux density is 10.2 MW / m³. 2 The total heat conduction within the initial 2 seconds is 8.9 MJ / m. 2 .

[0082] After repeating the experiment 3 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 103°; after repeating the experiment 5 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 101°; after repeating the experiment 7 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 100°; after repeating the experiment 9 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 99°.

[0083] S4. After repeating the experiment multiple times, the thickness and composition of the naturally deposited film were determined using characterization methods, and the melting point of the deposited film was calculated. In terms of composition, in oxide form, after seven repetitions, the composition of the naturally deposited film was 29.32 wt.% SiO2 ~ 41.98 wt.% MnO ~ 28.70 wt.% FeO. At this point, the thickness of the deposited film reached 5.87 μm.

[0084] Core loss P of finished plate 10 / 50 The magnetic flux density is 0.5~0.8 W / Kg, and the magnetic induction intensity B 50 It has a weight of approximately 1.54 T, a tensile strength of 595 MPa, and a yield strength of 472 MPa.

[0085] Example 8

[0086] In this embodiment, rare earth-modified high-silicon non-oriented silicon steel is produced based on the following steps:

[0087] S1. Non-oriented silicon steel is smelted using a vacuum induction furnace, and the chemical composition of the molten steel is controlled as follows (mass percentage): C ≤ 0.003%, Si: 3.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, La+Ce: 0.015%, with the balance being Fe and unavoidable impurities (the molar ratio of La to Ce is 1:2.3).

[0088] S2. Heat the molten steel to a superheat of approximately 90°C and pour it into a twin-roll thin-strip continuous casting equipment for casting. The casting rolls are made of copper, with a roll gap of 1.8~2.0 mm, and a casting speed of 0.7 m / s. Figure 1 As shown, the measured wetting angle between the molten steel and the crystallizing roll was 110°, which was 17.3% lower than that of Comparative Example 2, indicating a significant improvement in wettability.

[0089] S3. Maintain a constant cooling water temperature, measure the real-time temperature of the molten steel after contact with the crystallizing roll, and calculate the interfacial heat flux density. The peak heat flux density is 8.8 MW / m³. 2 The total heat conduction within the initial 2 seconds is 6.2 MJ / m. 2 Compared to Comparative Example 2, the peak heat flux density increased by 36.7%, and the interfacial heat transfer was significantly enhanced.

[0090] After repeating the experiment 3 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 107°; after repeating the experiment 5 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 105°; after repeating the experiment 7 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 104°; after repeating the experiment 9 times, the wetting angle between the molten steel and the crystallizing roll was measured to be 103°.

[0091] S4. After repeating the experiment multiple times, the thickness and composition of the naturally deposited film were determined using characterization methods, and the melting point of the deposited film was calculated. The thicknesses of the naturally deposited film were 1.973 μm (3 times), 2.782 μm (5 times), 3.398 μm (7 times), and 4.138 μm (9 times). The average deposition rate of the naturally deposited film was 0.460 μm / cycle, which increased by 20.77% compared to Comparative Example 2. In addition, in terms of composition, in oxide form, after repeating the experiment 7 times, the composition of the naturally deposited film was 31.29 wt.% SiO2~42.73 wt.% MnO~25.98 wt.% FeO, which decreased by approximately 20.9% compared to Comparative Example 2.

[0092] Core loss P of finished plate 10 / 50 The magnetic flux density is 0.5~1.0 W / Kg, and the magnetic induction intensity B 50 It has a strength of 1.48 T, a tensile strength of 692 MPa, and a yield strength of 521 MPa.

[0093] Comparative Example 1

[0094] In this comparative example, the preparation of non-oriented silicon steel by thin strip continuous casting is based on the following steps:

[0095] S1. Non-oriented silicon steel is smelted in a vacuum induction furnace, and the chemical composition of the molten steel is controlled as follows: C ≤ 0.003%, Si: 2.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, with the balance being Fe and unavoidable impurities.

[0096] S2. Heat the molten steel to a superheat of approximately 50°C and pour it into a twin-roll thin strip continuous casting machine for casting. The casting rolls are made of copper, with a roll gap of 1.8~2.0 mm, and a casting speed of 0.7 m / s. Figure 1 As shown, the wetting angle between the molten steel and the crystallizing roll was measured to be 127°.

[0097] S3. Maintain a constant cooling water temperature, measure the real-time temperature of the molten steel after contact with the crystallizing roll, and calculate the interfacial heat flux density. The peak heat flux density is 7.7 MW / m³. 2 The total heat conduction within the initial 2 seconds is 5.2 MJ / m. 2 .

[0098] S4. After repeating the experiment multiple times, characterization methods were used to determine the thickness and composition of the naturally deposited film, and the melting point of the deposited film was calculated. For example... Figure 2As shown, the thicknesses of the naturally deposited films were 1.429 μm (3 times), 2.196 μm (5 times), 2.602 μm (7 times), and 3.061 μm (9 times), with an average deposition rate of 0.34 μm / time. Furthermore, in oxide form, the composition of the naturally deposited films was 36.73 wt.% SiO2 ~ 41.05 wt.% MnO ~ 22.22 wt.% FeO.

[0099] Core loss P of finished plate 10 / 50 The magnetic flux density is 1.4~1.8 W / Kg, and the magnetic induction intensity B 50 It has a strength of 1.50 T, a tensile strength of 420 MPa, and a yield strength of 316 MPa.

[0100] Comparative Example 2

[0101] In this comparative example, high-silicon non-oriented silicon steel was prepared by thin-strip continuous casting based on the following steps:

[0102] S1. Non-oriented silicon steel is smelted using a vacuum induction furnace, and the chemical composition of the molten steel is controlled as follows (mass percentage): C ≤ 0.003%, Si: 3.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, with the balance being Fe and unavoidable impurities.

[0103] S2. Heat the molten steel to a superheat of approximately 50°C and pour it into a twin-roll thin strip continuous casting machine for casting. The casting rolls are made of copper, with a roll gap of 1.8~2.0 mm, and a casting speed of 0.7 m / s. Figure 1 As shown, the wetting angle between the molten steel and the crystallizing roll was measured to be 133°.

[0104] S3. Maintain a constant cooling water temperature, measure the real-time temperature of the molten steel after contact with the crystallizing roll, and calculate the interfacial heat flux density. The peak heat flux density is 6.4 MW / m³. 2 The total heat conduction within the initial 2 seconds is 4.6 MJ / m. 2 .

[0105] S4. After repeating the experiment multiple times, the thickness and composition of the naturally deposited film were determined using characterization methods, and the melting point of the film was calculated. The thicknesses of the naturally deposited films were 1.615 μm (3 times), 2.438 μm (5 times), 2.992 μm (7 times), and 3.428 μm (9 times), with an average deposition rate of 0.38 μm / cycle. Furthermore, in oxide form, after repeating the experiment 7 times, the composition of the naturally deposited film was 39.56% SiO2~43.00% MnO~17.44% FeO.

[0106] Core loss P of finished plate 10 / 50The magnetic flux density is 1.0~1.5 W / Kg, and the magnetic induction intensity B is... 50 The strength is 1.31 T, the tensile strength is 551 MPa, and the yield strength is 414 MPa.

[0107]

[0108]

[0109] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for reducing silica on the surface of crystallizing rolls used in thin strip continuous casting of non-oriented silicon steel, characterized in that: The following steps are included: S1. Adjust the molten steel for smelting non-oriented silicon steel, and adjust and control the chemical composition of the molten steel by mass percentage as follows: C ≤ 0.003%, Si: 2.5 ~ 3.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, mixed rare earth: 0.015% ~ 0.15%, with the balance being Fe and unavoidable impurities; S2. The molten steel obtained in step S1 is injected into a twin-roll thin strip continuous casting equipment, where it contacts the rotating crystallizing rolls to form a molten pool; at a cooling rate of 10... 2 ~ 10 4 Casting is carried out under sub-rapid solidification conditions of ℃ / s to obtain a casting strip; the casting temperature is controlled at a superheat of 50~95℃, Ar gas is used as the protective atmosphere throughout the process, water is used as the cooling medium, the casting roll material is copper, the roll gap is 1.8~2.0mm, and the casting speed is 0.6~0.7 m / s. S3. After step S2, a natural deposition film is formed on the surface of the crystallizing roller during the cooling process of the molten steel.

2. The method for reducing silica on the surface of the crystallizing roll used in thin strip continuous casting of non-oriented silicon steel according to claim 1, characterized in that: In step S1, the mixed rare earth elements are selected from at least two of La, Ce, Y, and Sc. Preferably, they are La and Ce.

3. The method for reducing silica on the surface of the crystallizing roll used in thin strip continuous casting of non-oriented silicon steel according to claim 1, characterized in that: Includes the following steps: S1. Adjust the molten steel for smelting non-oriented silicon steel, and adjust and control the chemical composition of the molten steel by mass percentage as follows: C ≤ 0.003%, Si: 2.5 ~ 2.8%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, mixed rare earth: 0.015% ~ 0.02%, with the balance being Fe and unavoidable impurities; the mixed rare earth is composed of La and Ce in a molar ratio of 1:2~2.3; S2. The molten steel obtained in step S1 is injected into a twin-roll thin strip continuous casting equipment, where it contacts the rotating crystallizing rolls to form a molten pool; at a cooling rate of 10... 2 ~ 10 4 Casting is carried out under sub-rapid solidification conditions of ℃ / s to obtain the casting strip; the casting temperature is controlled at a superheat of 50~55℃, Ar gas is used as the protective atmosphere throughout the process, water is used as the cooling medium, the casting roll material is copper, the roll gap is 1.8~2.0mm, and the casting speed is 0.6~0.7 m / s.

4. The method for reducing silica on the surface of the crystallizing roll used in thin strip continuous casting of non-oriented silicon steel according to claim 3, characterized in that: The SiO2 content in the film deposited on the surface of the crystallizing roller decreased to 28.9~29 wt.%.

5. The method for reducing silica on the surface of the crystallizing roll used in thin strip continuous casting of non-oriented silicon steel according to claim 1, characterized in that: S1. Non-oriented silicon steel is smelted using a vacuum induction furnace, and the chemical composition of the molten steel is controlled as follows (mass percentage): C ≤ 0.003%, Si: 3.2~3.5%, Mn: 0.27%, P ≤ 0.004%, S ≤ 0.003%, N ≤ 0.003%, mixed rare earth: 0.015%~0.02%, with the balance being Fe and unavoidable impurities; the mixed rare earth is composed of La and Ce in a molar ratio of 1:1~1.

2. S2. Heat the molten steel to a superheat of 85~90℃ and pour it into a twin-roll thin strip continuous casting equipment for casting. The casting rolls are made of copper, the roll gap is 1.8~2.0 mm, and the casting speed is 0.7 m / s.

6. The method for reducing silica on the surface of the crystallizing roll used in thin strip continuous casting of non-oriented silicon steel according to claim 5, characterized in that: The SiO2 content in the crystallization roller deposited film decreased to 29.2~29.35 wt.%.

7. A method for reducing silica on the surface of a crystallizing roll used in thin strip continuous casting of non-oriented silicon steel according to claim 6, characterized in that: The mixed rare earth element is composed of La and Ce in a molar ratio of 1:

1.

8. A method for reducing silica on the surface of a crystallizing roll used in thin strip continuous casting of non-oriented silicon steel according to claim 4 or 6, characterized in that: The deposition film on the surface of the crystallizing roller is a naturally deposited film obtained after seven repeated experiments.

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