A high-silicon steel strip, its preparation apparatus, method and application

Abstract

This application discloses a high-silicon steel strip and its preparation apparatus, method, and application, belonging to the field of non-oriented high-silicon steel technology. The preparation apparatus includes: a crucible for planar flow casting equipment, with a heater surrounding the crucible for heating and holding the master alloy to form high-silicon steel liquid; a nozzle gap at the bottom of the crucible; a cooling copper roller located below the crucible for cooling and rapidly solidifying the high-silicon steel liquid to form an initial high-silicon steel strip of a certain thickness; and a rolling protection device located near the cooling copper roller, which creates a locally sealed atmosphere by introducing inert gas and continuously acts on the area between the high-silicon steel liquid and the cooling copper roller during the casting process. The technical solution of this application sets a rolling protection device near the surface of the cooling copper roller during the solidification process of the high-silicon steel liquid. This rolling protection device combines forced rolling and local inert atmosphere protection functions to improve the wettability of the steel liquid to the cooling copper roller and the forming stability.

Description

Technical Field

[0001] This application belongs to the field of non-oriented high silicon steel technology, specifically relating to a high silicon steel strip and its preparation apparatus, method and application. Background Technology

[0002] With the rapid development of new energy vehicles, rail transit, and smart grids, electromagnetic equipment such as motors are placing higher demands on the performance of soft magnetic materials. Non-oriented silicon steel, due to its excellent magnetic properties and process adaptability, has long been the mainstream soft magnetic material widely used in various motors. The quality of its magnetic properties directly affects the energy efficiency and power density of the entire device. However, with the continuous development of high-frequency and high-efficiency motors, traditional non-oriented silicon steel is gradually revealing performance bottlenecks in reducing iron losses and increasing magnetic induction intensity. Therefore, developing high-performance silicon steel materials has become crucial for improving motor energy efficiency and meeting the needs of advanced electromagnetic equipment.

[0003] High-silicon steel, especially alloys with a silicon content of 6.5 wt%, is considered representative of next-generation high-performance soft magnetic materials. Compared to traditional silicon steel, high-silicon steel has higher resistivity, lower magnetostriction, and weaker magnetic anisotropy, which can significantly reduce eddy current losses under high-frequency conditions, reduce operating noise, and improve magnetic response performance in rotating magnetic fields. With these properties, high-silicon steel shows broad application prospects in advanced fields such as high-efficiency motors, power electronics, and aerospace power supplies.

[0004] However, high-silicon steel exhibits high room-temperature brittleness and poor plasticity, making it difficult to stabilize and produce strips through conventional rolling, thus becoming a key bottleneck restricting its engineering applications. To overcome the limitations of traditional processes, planar flow casting technology is considered a feasible near-net-shape preparation scheme. This technology, by directly casting high-temperature molten steel into thin strips, effectively suppresses the formation of ordered phases in high-silicon steel and avoids multiple rolling processes, improving the processing adaptability of high-silicon steel. Currently, planar flow casting technology has been successfully applied in the industrial production of amorphous alloy strips and has shown good development potential in the preparation of high-silicon steel thin strips, providing a new technical path for the industrial promotion of high-silicon steel.

[0005] Despite this, applying planar flow casting technology to high-silicon steel still faces significant challenges. Compared to amorphous alloys, high-silicon steel has a higher melting point and melt viscosity, making it difficult to fully wet the surface of the cooling copper rollers during flow. This results in reduced cooling efficiency, uneven solidification, and consequently, surface defects and thickness fluctuations. Furthermore, poor wettability can lead to unstable steel flow, causing problems such as strip forming interruptions and edge tearing, affecting forming quality and production stability. These issues have become key technical bottlenecks restricting the high-quality production of high-silicon steel strips using planar flow casting, and effective solutions are urgently needed. Summary of the Invention

[0006] This application provides a high-silicon steel strip and its preparation apparatus, method, and application to solve any of the above-mentioned and other potential problems in the prior art. Regarding the high-silicon steel strip and its preparation method, the technical solution of this application sets a rolling protection device near the surface of the cooling copper roller during the solidification process of the high-silicon steel liquid. This rolling protection device has both forced rolling and local inert atmosphere protection functions, used to improve the wettability of the steel liquid to the cooling copper roller and the forming stability.

[0007] According to a first aspect of the technical solution of this application, an apparatus for preparing high-silicon steel strip is provided, the apparatus comprising:

[0008] A crucible for a planar flow casting equipment, wherein a heater is provided around the crucible for heating and heat preservation of the master alloy to form high-silicon steel liquid, and a nozzle gap is provided at the bottom of the crucible;

[0009] The cooling copper roller, located at the bottom of the crucible of the planar flow casting equipment, is used to cool and rapidly solidify the high-silicon steel liquid to form an initial thin strip of high-silicon steel of a certain thickness.

[0010] The rolling protection device, located near the cooling copper roller, creates a locally enclosed atmosphere by introducing inert gas and continuously acts on the area between the high-silicon steel liquid and the cooling copper roller during the casting process.

[0011] Furthermore, the preparation apparatus also includes a thickness detector for high-silicon steel strips and a winding device.

[0012] Here, "rolling protection" refers to a composite control function that combines forced rolling with inert atmosphere protection. Its core is twofold: first, by setting up a rolling mechanism with pressure regulation, appropriate external pressure is applied between the high-silicon steel molten material and the cooling copper rolls to promote the full spreading and rapid adhesion of the molten steel to the copper roll surface, achieving stable control of the forming process; second, a locally enclosed inert atmosphere environment is established in the rolling area to inhibit contact between the molten steel and oxygen in the air, reducing the risk of oxidation and further improving the surface quality of the strip.

[0013] Furthermore, the calendering protection device includes a calendering protective outer cover, a directional calendering inner layer structure, a directional calendering outer layer structure, and a vent pipe.

[0014] The vent pipe is connected to the top of the calendering protective cover and is used to introduce an inert gas at a certain pressure into the calendering protective cover.

[0015] Both the inner and outer directional rolling layers are permeable plate-like structures, arranged from the inside to the outside inside the rolling protective cover, to guide the inert gas to be evenly distributed in the area between the high-silicon steel liquid and the cooling copper roller.

[0016] Furthermore, the directional calendered inner layer structure is provided with a uniformly distributed array of circular holes, the diameter of which ranges from 5 to 10 mm and the number of which ranges from 200 to 400.

[0017] The purpose of this design is to achieve uniform dispersion and slow release of high-pressure inert gas introduced into the vent pipe through the array of circular holes, effectively regulate the gas flow and distribution, prevent local concentrated gas injection from disturbing the molten steel, avoid voids, bulges or strip breakage defects caused by this, and ensure the continuity and stability of the strip forming process.

[0018] Furthermore, the directional calendered outer layer structure is provided with multiple rows of parallel transverse slit structures, and the outer layer edge is provided with vertical slit structures perpendicular to the transverse slits;

[0019] The aperture range of the transverse and vertical slit structures is 0.3 to 1.0 mm, and the number of rows of the transverse slit structure is 10 to 30.

[0020] The purpose of this design is to achieve stable and directional output of inert gas by using parallel slit structures, so that the airflow forms a stable cover at the interface between the high-silicon steel liquid and the cooling copper roller, thereby providing a continuous and balanced auxiliary rolling force during the rolling process, improving the forming quality and surface density of the initial strip; at the same time, the vertical slit structure at the edge creates a protective air curtain around the airflow outlet area, effectively blocking outside air from entering the casting strip area and inhibiting the occurrence of oxidation reaction.

[0021] According to a second aspect of the technical solution of this application, a method for preparing high-silicon steel thin strip using the preparation apparatus according to any one of the above aspects is provided, the specific steps of the method being as follows:

[0022] S1) Weigh each chemical component according to the design composition, and smelt the raw material as a master alloy with uniform composition;

[0023] S2) The master alloy is placed in the crucible of a planar flow casting equipment and heated and kept at a certain temperature to form a high-silicon steel liquid;

[0024] S3) Activate the rolling protection device located near the surface of the cooling copper roller, and introduce inert gas at a certain pressure into the rolling protection device;

[0025] S4) Apply pressure above the high silicon steel liquid to spray it through the nozzle gap onto the surface of the rotating cooling copper roller. Under the action of the inert rolling atmosphere formed by the rolling protection device, the high silicon steel liquid and the cooling copper roller fully adhere to each other and solidify rapidly to form an initial thin strip of high silicon steel of a certain thickness.

[0026] S5) The initial high-silicon steel strip is heat-treated under a protective atmosphere to obtain a finished high-silicon steel strip with excellent magnetic properties.

[0027] Furthermore, the melting temperature in S1) is 1550–1650°C.

[0028] Furthermore, the heat preservation temperature of the high silicon steel liquid in S2) is 1480~1600℃.

[0029] Furthermore, the inert gas introduced in step S3) is argon or nitrogen, and the gas pressure is 0.1 to 0.6 MPa.

[0030] Furthermore, in S4), the rotational speed of the cooling copper roller is 5 to 50 m / s, and the initial thickness of the high-silicon steel strip formed is 0.03 to 0.15 mm.

[0031] Furthermore, in step S5), the heat treatment atmosphere is a H2 / N2 mixed gas, the heat treatment temperature is 1000–1150°C, and the holding time is 0.5–3 hours.

[0032] Furthermore, the chemical composition of the high-silicon steel finished strip is as follows: Si content is 4.5-7.0 wt%, with the remainder being Fe and unavoidable impurities.

[0033] Furthermore, the high-silicon steel finished strip has the following magnetic properties: magnetic induction intensity B8 ≥ 1.24T, iron loss P 10 / 400 ≤15.8W / kg, P 2 / 5000 ≤17.5W / kg.

[0034] According to a third aspect of the technical solution of this application, a high-silicon steel finished strip is provided, which is prepared by the preparation method described in any of the above aspects.

[0035] According to the fourth aspect of the technical solution of this application, an application of the high-silicon steel finished strip described above is provided in the core manufacturing of soft magnetic devices.

[0036] Compared with the prior art, the advantages and beneficial effects of this application are as follows:

[0037] By adding a rolling protection device near the cooling copper roller in planar flow casting, the synergistic effect of anti-oxidation protection and auxiliary rolling forming is achieved, which effectively improves the forming quality of high silicon steel strip, enhances the continuity and consistency of the production process, and solves key problems such as poor wettability of molten steel and unstable forming.

[0038] It simplifies the traditional multi-pass rolling process of silicon steel, significantly reduces energy consumption and carbon emissions, meets the requirements of the national "dual carbon" strategy for green manufacturing, and improves the environmental and economic benefits of production.

[0039] The prepared high-silicon steel strips possess excellent soft magnetic properties, meeting the application needs of new energy vehicles, power electronics, and high-efficiency motors, and have broad prospects for promotion and industrialization. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of a preparation method according to an embodiment of this application;

[0041] Figure 2 This is a schematic diagram of a rolling protection device according to an embodiment of this application. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of this application.

[0043] This application provides a high-silicon steel strip and its preparation apparatus, method and application. For the high-silicon steel strip and its preparation method, a rolling protection device is set near the surface of the cooling copper roller during the solidification process of the high-silicon steel liquid. The rolling protection device has both forced rolling and local inert atmosphere protection functions, which is used to improve the wettability of the steel liquid to the cooling copper roller and the forming stability.

[0044] This application first provides an apparatus for preparing high-silicon steel strips, the apparatus comprising:

[0045] The planar flow casting equipment crucible 1 has a heater 2 around its periphery for heating and heat-preserving the master alloy to form high-silicon steel liquid 3, and a nozzle gap 4 is provided at the bottom of the crucible.

[0046] Cooling copper roller 5, located at the bottom of the crucible of the planar flow casting equipment, is used to cool and quickly solidify the high silicon steel liquid to form an initial thin strip 6 of high silicon steel of a certain thickness;

[0047] The rolling protection device 7 is located near the cooling copper roller. It creates a locally enclosed atmosphere by introducing inert gas 8 and continuously acts on the area between the high silicon steel liquid and the cooling copper roller during the casting process.

[0048] In a preferred embodiment, the preparation apparatus further includes a thickness gauge 9 for high-silicon steel strip and a winding device 10.

[0049] In a preferred embodiment, the calendering protection device includes a calendering protective outer cover 11, a directional calendering inner layer structure 12, a directional calendering outer layer structure 13, and a vent pipe 14.

[0050] The vent pipe 14 is connected to the top of the calendering protective cover 11 and is used to introduce an inert gas at a certain pressure into the calendering protective cover 11.

[0051] Both the directional calendering inner layer structure 12 and the directional calendering outer layer structure 13 are breathable plate-like structures, respectively arranged inside the calendering protective cover from the inside to the outside, to guide the inert gas to be evenly distributed within the protected area.

[0052] In a preferred embodiment, the directional calendered inner layer structure 12 is provided with a uniformly distributed array of circular holes 15, the diameter of the circular holes in the array of circular holes 15 being 5 to 10 mm and the number being 200 to 400.

[0053] In a preferred embodiment, the directional calendered outer layer structure 13 is provided with multiple rows of parallel transverse slit structures 16, and the outer edge is provided with vertical slit structures 17 perpendicular to the transverse slits.

[0054] The aperture range of the transverse slit structure 16 and the vertical slit structure 17 is 0.3 to 1.0 mm, and the number of rows of the transverse slit structure is 10 to 30.

[0055] This application also provides a method for preparing high-silicon steel strips using the preparation apparatus described above. For example... Figure 1 As shown, the specific steps of the method are as follows:

[0056] S1) Weigh each chemical component according to the designed composition, and the raw material for smelting is a homogeneous master alloy. In a preferred embodiment, the smelting temperature in S1) is 1550–1650°C.

[0057] S2) The master alloy is placed in crucible 1 of a planar casting equipment and heated and held at a certain temperature to form high-silicon steel liquid 3. In a preferred embodiment, the holding temperature of the high-silicon steel liquid in S2) is 1480-1600℃.

[0058] S3) Activate the rolling protection device 7 located near the surface of the cooling copper roller 5, and introduce an inert gas 8 at a certain pressure into the rolling protection device. In a preferred embodiment, the inert gas introduced in S3) is argon or nitrogen, and the gas pressure is 0.1 to 0.6 MPa.

[0059] S4) Pressure is applied above the high-silicon steel molten material, causing it to be sprayed through the nozzle gap 4 onto the surface of the rotating cooling copper roller 5. Under the action of the inert rolling atmosphere formed by the rolling protection device, the high-silicon steel molten material and the cooling copper roller fully adhere and rapidly solidify, forming an initial high-silicon steel strip 6 of a certain thickness. In a preferred embodiment, the rotational speed of the cooling copper roller in S4) is 5-50 m / s, and the thickness of the formed initial high-silicon steel strip is 0.03-0.15 mm.

[0060] S5) The initial high-silicon steel strip is heat-treated under a protective atmosphere to obtain a finished high-silicon steel strip with excellent magnetic properties. In a preferred embodiment, the heat treatment atmosphere in S5) is a H2 / N2 mixed gas, the heat treatment temperature is 1000-1150℃, and the holding time is 0.5-3h.

[0061] In a preferred embodiment, the chemical composition of the high-silicon steel finished strip is: Si content of 4.5-7.0 wt%, with the remainder being Fe and unavoidable impurities.

[0062] Here, the high-silicon steel finished strip has the following magnetic properties: magnetic induction intensity B8 ≥ 1.24T, iron loss P 10 / 400 ≤15.8W / kg, P 2 / 5000 ≤17.5W / kg.

[0063] The present application also provides a high-silicon steel finished strip prepared by the preparation method described above.

[0064] This application provides another application of high-silicon steel finished strips as described above in the manufacture of cores for soft magnetic devices.

[0065] The technical principle of this application is as follows:

[0066] By setting up a dedicated rolling protection device near the cooling copper roller and continuously introducing inert gas at a certain pressure, a local stable oxygen-free protective environment can be created at the moment the molten steel is sprayed out, which can effectively inhibit the oxidation of the molten steel and improve the surface quality of the strip.

[0067] The directional rolling action of inert gas creates a certain pressure between the melt and the copper roller, which promotes the molten steel to adhere more fully to the surface of the cooling copper roller, improves the interfacial wettability and heat transfer efficiency, thereby accelerating the solidification rate, improving the cooling uniformity, and ensuring the continuity and stability of the casting process.

[0068] The rolling protection device employs a unique double-layer structure design. The inner layer is a uniformly distributed array of circular holes, which effectively regulates gas flow and distribution, preventing voids or strip breakage caused by localized overpressure. The outer layer consists of parallel transverse slits, which pressurize the gas onto the interface between the molten steel and the cooling copper rollers in a stable and directional manner, achieving a continuous and stable auxiliary rolling effect and improving the strip forming quality. Vertical slits are set at the edges to form a protective air curtain around the gas outlet area, preventing air from intruding into the casting zone. Here, the circular hole array structure, the straight (transverse) slit structure, and the vertical slit structure are all indispensable because these three structures complement each other and work synergistically to form a complete atmosphere protection system from gas homogenization and stable output to edge sealing. The absence of any one part will lead to uneven airflow distribution, incomplete gas coverage, or weakened protection effect, thereby affecting the forming quality and magnetic properties of the high-silicon steel strip.

[0069] By accelerating the solidification rate, the formation of ordered phases in high-silicon steel is effectively suppressed, the ductility of the strip is improved, and a good microstructure is laid for subsequent heat treatment, ultimately producing high-silicon steel strips with excellent magnetic properties.

[0070] Example 1

[0071] A method for preparing high-silicon steel strip, wherein the chemical composition of the steel (mass percentage) is: Si: 6.54%, with the remainder being Fe and unavoidable impurities. The preparation method employs... Figure 1 The preparation apparatus includes: a planar flow casting equipment crucible 1, a cooling copper roller 5, a rolling protection device 7, a thickness gauge 9, and a coiler 10. Figure 2 As shown, the calendering protection device includes a calendering protective outer cover 11, a directional calendering inner layer structure 12, a directional calendering outer layer structure 13, and a vent pipe 14. The vent pipe 14 is connected to the top of the calendering protective outer cover 11 and is used to introduce inert gas at a certain pressure into the calendering protective outer cover. Both the directional calendering inner layer structure 12 and the directional calendering outer layer structure 13 are breathable plate-like structures, respectively arranged inside the calendering protective outer cover from the inside out, to guide the inert gas to distribute evenly within the protected area. The directional calendering inner layer structure has a uniformly distributed array of circular holes 15, and the directional calendering outer layer structure has multiple rows of parallel transverse slit structures 16, with vertical slit structures 17 perpendicular to the transverse slits at the outer edge.

[0072] Specifically, the preparation method includes the following steps:

[0073] (1) Based on the chemical composition of the above high silicon steel, the raw materials are smelted at a temperature of 1600℃ to form a master alloy with uniform composition.

[0074] (2) Place the master alloy in the crucible of the planar casting equipment and heat it to 1520℃ and hold it to form a high silicon steel liquid;

[0075] (3) Start the rolling protection device set near the surface of the cooling copper roller, and introduce 0.15 MPa of nitrogen into the device to create a local closed atmosphere area. This device will continue to act on the contact area between the molten steel and the cooling copper roller during the subsequent casting process.

[0076] (4) Apply pressure above the molten steel so that it is sprayed through the nozzle gap onto the surface of the cooling copper roller with a rotation speed of 40m / s. Under the action of the inert rolling atmosphere formed by the rolling protection device, the molten steel and the cooling copper roller are fully bonded and quickly solidified to form an initial thin strip of high silicon steel with a thickness of 0.035mm.

[0077] (5) The strip is heat-treated at 1100℃ for 1.0h in a mixed H2 / N2 atmosphere to obtain a high-silicon steel finished strip with excellent magnetic properties. The magnetic properties are: magnetic induction intensity B8: 1.26T, iron loss P 10 / 400 9.8 W / kg, P 2 / 5000 : 9.4W / kg.

[0078] Example 2

[0079] A method for preparing high-silicon steel strip, wherein the chemical composition of the steel is as follows (mass percentage): Si: 4.57%, with the remainder being Fe and unavoidable impurities. The preparation method includes the following steps:

[0080] (1) Based on the chemical composition of the above high silicon steel, the raw materials are smelted at a temperature of 1580℃ to form a master alloy with uniform composition.

[0081] (2) Place the master alloy in the crucible of the planar flow casting equipment and heat it to 1500℃ and hold it to form a high silicon steel liquid;

[0082] (3) Activate the rolling protection device located near the surface of the cooling copper roller, and introduce 0.35MPa of argon gas into the device to create a locally enclosed atmosphere area;

[0083] (4) Apply pressure above the molten steel to spray it through the nozzle gap onto the surface of the cooling copper roller with a rotation speed of 25m / s, and form an initial thin strip with a thickness of 0.096mm under the action of the protective device.

[0084] (5) The strip was annealed at 1000℃ for 3.0h in a H2 / N2 mixed atmosphere to obtain a high-silicon steel finished strip with excellent magnetic properties. The magnetic properties are: magnetic induction intensity B8: 1.29T, iron loss P 10 / 400 15.4 W / kg, P 2 / 5000 14.8 W / kg.

[0085] Example 3

[0086] A method for preparing high-silicon steel strip, wherein the chemical composition of the steel is as follows (mass percentage): Si: 5.76%, with the remainder being Fe and unavoidable impurities. The preparation method includes the following steps:

[0087] (1) Based on the chemical composition of the above high silicon steel, the raw materials are smelted at a temperature of 1620℃ to form a master alloy with uniform composition.

[0088] (2) Place the master alloy in the crucible of the planar casting equipment and heat it to 1540℃ and hold it to form a high silicon steel liquid;

[0089] (3) Activate the rolling protection device located near the surface of the cooling copper roller, and introduce 0.20MPa of nitrogen into the device to create a locally enclosed atmosphere area;

[0090] (4) Apply pressure above the molten steel to spray it through the nozzle gap onto the surface of the cooling copper roller with a rotation speed of 50m / s, and form an initial thin strip with a thickness of 0.030mm under the action of the protective device.

[0091] (5) The strip was annealed at 1050℃ for 2.0h in a H2 / N2 mixed atmosphere to obtain a high-silicon steel finished strip with excellent magnetic properties. The magnetic properties are: magnetic induction intensity B8: 1.26T, iron loss P 10 / 400 12.6 W / kg, P 2 / 5000 10.9 W / kg.

[0092] Example 4

[0093] A method for preparing high-silicon steel strip, wherein the chemical composition of the steel is as follows (mass percentage): Si: 6.98%, with the remainder being Fe and unavoidable impurities. The preparation method includes the following steps:

[0094] (1) Based on the chemical composition of the above high silicon steel, the raw materials are smelted at a temperature of 1550℃ to form a master alloy with uniform composition.

[0095] (2) Place the master alloy in the crucible of the planar casting equipment and heat it to 1480℃ and hold it to form a high silicon steel liquid;

[0096] (3) Activate the rolling protection device located near the surface of the cooling copper roller, and introduce 0.40MPa of argon gas into the device to create a locally enclosed atmosphere area;

[0097] (4) Apply pressure above the molten steel to spray it through the nozzle gap onto the surface of the cooling copper roller with a rotation speed of 20m / s, and form an initial thin strip with a thickness of 0.112mm under the action of the protective device.

[0098] (5) The strip was annealed at 1150℃ for 0.5h in a H2 / N2 mixed atmosphere to obtain a high-silicon steel finished strip with excellent magnetic properties. The magnetic properties are: magnetic induction intensity B8: 1.24T, iron loss P 10 / 400 10.9 W / kg, P 2 / 5000 15.7 W / kg.

[0099] Example 5

[0100] A method for preparing high-silicon steel strip, wherein the chemical composition of the steel is as follows (mass percentage): Si: 5.13%, with the remainder being Fe and unavoidable impurities. The preparation method includes the following steps:

[0101] (1) Based on the chemical composition of the above high silicon steel, the raw materials are smelted at a temperature of 1650℃ to form a master alloy with uniform composition.

[0102] (2) Place the master alloy in the crucible of the planar casting equipment and heat it to 1600℃ and hold it to form a high silicon steel liquid;

[0103] (3) Activate the rolling protection device located near the surface of the cooling copper roller, and introduce 0.55MPa of argon gas into the device to create a locally enclosed atmosphere area;

[0104] (4) Apply pressure above the molten steel to spray it through the nozzle gap onto the surface of the cooling copper roller with a rotation speed of 10m / s, and form an initial thin strip with a thickness of 0.146mm under the action of the protective device.

[0105] (5) The strip is annealed at 1080℃ for 1.5h in a H2 / N2 mixed atmosphere to obtain a high-silicon steel finished strip with excellent magnetic properties. The magnetic properties are: magnetic induction intensity B8: 1.27T, iron loss P 10 / 400 15.8 W / kg, P 2 / 5000 17.5 W / kg.

[0106] Example 6

[0107] A method for preparing high-silicon steel strip, wherein the chemical composition of the steel is as follows (mass percentage): Si: 6.07%, with the remainder being Fe and unavoidable impurities. The preparation method includes the following steps:

[0108] (1) Based on the chemical composition of the above high silicon steel, the raw materials are smelted at a temperature of 1570℃ to form a master alloy with uniform composition.

[0109] (2) Place the master alloy in the crucible of the planar casting equipment and heat it to 1580℃ and hold it to form a high silicon steel liquid;

[0110] (3) Activate the rolling protection device located near the surface of the cooling copper roller, and introduce 0.30MPa of nitrogen into the device to create a locally enclosed atmosphere area;

[0111] (4) Apply pressure above the molten steel to spray it through the nozzle gap onto the surface of the cooling copper roller with a rotation speed of 30m / s, and form an initial thin strip with a thickness of 0.068mm under the action of the protective device.

[0112] (5) The strip was annealed at 1120℃ for 2.5h in a H2 / N2 mixed atmosphere to obtain a high-silicon steel finished strip with excellent magnetic properties. The magnetic properties are: magnetic induction intensity B8: 1.25T, iron loss P 10 / 400 11.3 W / kg, P 2 / 5000 12.1 W / kg.

[0113] Comparative Example 1

[0114] A method for preparing high-silicon steel strip, wherein the chemical composition of the steel is: Si: 6.54% by mass, with the remainder being Fe and unavoidable impurities. The preparation method is the same as in Example 1, except that no rolling protection device is set, and the molten steel is directly sprayed onto the surface of the cooling copper roller during the strip casting process.

[0115] Under these conditions, due to the lack of auxiliary rolling and local inert atmosphere protection between the molten steel and the cooling copper rolls, the wettability is poor, the interface is unstable, and obvious bulging and strip breakage occur on the strip surface. The strip continuity is poor, the yield of finished products is low, and the magnetic properties of the finished thin strip are: magnetic induction intensity B8: 1.21T, iron loss P 10 / 400 18.7 W / kg, P 2 / 5000 The concentration was 20.3 W / kg, which is significantly worse than that of Example 1.

[0116] Comparative Example 2

[0117] A method for preparing high-silicon steel strip, wherein the chemical composition of the steel by mass percentage is: Si: 5.76%, with the remainder being Fe and unavoidable impurities. The preparation method is basically the same as in Example 3, except that the rolling protection device only retains the directional rolling inner layer structure (equipped with a circular hole array) and does not provide the directional rolling outer layer structure.

[0118] Under these conditions, although the gas is initially dispersed through the circular aperture array, the lack of a directional transport structure results in a limited gas flow coverage, discontinuous calendering atmosphere, and insufficient local solidification. This leads to peeling and streaking defects on the strip surface. The magnetic properties of the finished thin strip are: magnetic induction intensity B8: 1.22T, iron loss P... 10 / 400 15.4 W / kg, P 2 / 5000 : 16.1 W / kg, performance is lower than that of Example 3.

[0119] Comparative Example 3:

[0120] A method for preparing high-silicon steel strip, wherein the chemical composition of the steel by mass percentage is: Si: 4.57%, with the remainder being Fe and unavoidable impurities. The preparation method is basically the same as in Example 2, except that the rolling protection device only retains the outer structure of directional rolling and does not set the inner structure of directional rolling (i.e., no circular hole array).

[0121] Under these conditions, the high-pressure inert gas enters the gap structure directly without pre-dispersion, leading to concentrated airflow and unstable flow velocity. This disturbs the surface of the molten steel, causing interface instability and damage to the solidified layer, resulting in ripples and strip defects on the strip surface. The magnetic properties of the finished thin strip are: magnetic induction intensity B8: 1.23T, iron loss P... 10 / 400 18.5 W / kg, P 2 / 5000 : 18.0 W / kg, performance is lower than that of Example 2.

[0122] In summary, this application provides a high-silicon steel strip, its preparation apparatus, method, and application. The rolling process using inert gas improves the wettability of molten steel, enhances cooling efficiency and forming stability, and significantly improves the surface quality of the strip. The process is simple and suitable for the continuous preparation of high-performance, ultra-thin high-silicon steel strips, exhibiting good energy-saving and consumption-reducing effects and promising engineering application prospects.

[0123] The above are only some preferred embodiments of this application, but this application is not limited thereto, and many improvements and modifications can be made. Any improvements and modifications made based on the basic principles of this application should be considered to fall within the protection scope of this application.

Claims

1. An apparatus for preparing high-silicon steel strips, characterized in that, The preparation apparatus includes: A crucible for a planar flow casting equipment, wherein a heater is provided around the crucible for heating and heat preservation of the master alloy to form high-silicon steel liquid, and a nozzle gap is provided at the bottom of the crucible; The cooling copper roller, located at the bottom of the crucible of the planar flow casting equipment, is used to cool and rapidly solidify the high-silicon steel liquid to form an initial thin strip of high-silicon steel of a certain thickness. The rolling protection device is located near the cooling copper roller. It creates a locally enclosed atmosphere by introducing inert gas and continuously acts on the area between the high-silicon steel liquid and the cooling copper roller during the casting process. The calendering protection device includes a calendering protective outer cover, a directional calendering inner layer structure, a directional calendering outer layer structure, and a vent pipe. The vent pipe is connected to the top of the calendering protective cover and is used to introduce an inert gas at a certain pressure into the calendering protective cover. Both the inner and outer layers of the directional rolling structure are breathable plate-like structures, which are respectively arranged inside the rolling protective cover from the inside to the outside, to guide the inert gas to be evenly distributed in the area between the high silicon steel liquid and the cooling copper roller. The directional calendered inner layer structure is provided with a uniformly distributed array of circular holes; The aperture of the circular hole array structure ranges from 5 to 10 mm, and the number ranges from 200 to 400. The outer layer structure of the directional calendering is provided with multiple rows of parallel transverse slit structures, and the outer edge is provided with vertical slit structures perpendicular to the transverse slits. The aperture range of the transverse and vertical slit structures is 0.3 to 1.0 mm, and the number of rows of the transverse slit structure is 10 to 30.

2. A method for preparing high-silicon steel strips based on the preparation apparatus according to claim 1, characterized in that, The specific steps of the method are as follows: S1) Weigh each chemical component according to the design composition, and smelt the raw material as a master alloy with uniform composition; S2) The master alloy is placed in a crucible of a planar flow casting equipment and heated and kept at a certain temperature to form a high-silicon steel liquid; S3) Activate the rolling protection device located near the surface of the cooling copper roller, and introduce inert gas at a certain pressure into the rolling protection device; S4) Apply pressure above the high silicon steel liquid to spray it through the nozzle gap onto the surface of the rotating cooling copper roller. Under the action of the inert rolling atmosphere formed by the rolling protection device, the high silicon steel liquid and the cooling copper roller fully adhere to each other and solidify rapidly to form an initial thin strip of high silicon steel of a certain thickness. S5) The initial high-silicon steel strip is heat-treated under a protective atmosphere to obtain the finished high-silicon steel strip.

3. The method for preparing high-silicon steel strip according to claim 2, characterized in that: The melting temperature in S1) is 1550~1650 ℃; The heat preservation temperature of the high silicon steel liquid in S2) is 1480~1600 ℃; The inert gas introduced in step S3) is argon or nitrogen, and the gas pressure is 0.1~0.6 MPa; The rotational speed of the cooling copper roller in S4) is 5~50 m / s, and the initial thickness of the high silicon steel strip formed is 0.03~0.15 mm; The heat treatment atmosphere in S5) is a H2 / N2 mixed gas, the heat treatment temperature is 1000~1150 ℃, and the holding time is 0.5~3 h.

4. The method for preparing high-silicon steel strip according to claim 2, characterized in that, The chemical composition of the high-silicon steel finished strip is as follows: Si content is 4.5-7.0 wt%, with the remainder being Fe and unavoidable impurities.

5. The method for preparing high-silicon steel strip according to claim 2, characterized in that, The high-silicon steel finished thin strip has the following magnetic properties: magnetic induction intensity B8≥1.24 T, iron loss P 10 / 400 ≤15.8 W / kg, P 2 / 5000 ≤17.5 W / kg.

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