A high magnetic induction oriented electrical steel and its annealing process

Abstract

This invention discloses a high-magnetic-induction oriented electrical steel and its annealing process, relating to the field of electrical steel manufacturing technology. The chemical composition, by mass percentage, is as follows: C: 0.03-0.045%, Si: 3.0-3.3%, Mn: 0.09-0.11%, Als: 0.025-0.035%, Nb: 0.018-0.023%, Cu: 0.09-0.11%, rare earth elements: 0.005-0.01%, V: 0.01-0.03%, B: 0.001-0.003%, Ti: 0.01-0.02%, Co: 0.5-1.0%, Ni: 0.3-0.8%, Ta: 0.005-0.015%, Hf: 0.005-0.012%, with the remainder being Fe and other unavoidable impurities. This high-magnetic-induction oriented electrical steel exhibits high magnetic induction intensity, low hysteresis loss, and a short production cycle.

Description

Technical Field

[0001] This invention relates to the field of electrical steel manufacturing technology, and in particular to a high magnetic orientation electrical steel and its annealing process. Background Technology

[0002] In modern power transmission and conversion systems, grain-oriented electrical steel is a key material for core components such as transformers and reactors, and its performance directly determines the energy efficiency and operational reliability of the equipment. With the advancement of global "dual carbon" goals, the demand for high-magnetic-induction, low-loss grain-oriented electrical steel in the power industry is experiencing explosive growth.

[0003] Traditional grain-oriented electrical steels rely on conventional alloying elements to regulate magnetic properties. However, due to the limited synergistic effect between elements, it is difficult to break through the performance bottleneck. They still have defects such as insufficient magnetic induction intensity and excessive hysteresis loss, which cannot meet the stringent requirements of ultra-high voltage and extra-high voltage transformers, and seriously affect the service life and stability of the transformers.

[0004] Existing manufacturing processes for grain-oriented electrical steel have several limitations. For example, conventional annealing processes struggle to precisely control grain growth and orientation, resulting in suboptimal texture and consequently affecting the steel's magnetic properties. Furthermore, current processes suffer from drawbacks such as longer production cycles, higher energy consumption, and difficulties in reducing production costs and improving efficiency.

[0005] To address the aforementioned issues, Chinese invention patent CN118272617B discloses a high-magnetic-induction oriented electrical steel and its annealing process. By weight percentage, it comprises: C 0.04-0.08wt%, Si 3.0-4.0wt%, Mn 0.05-0.2wt%, S 0.004-0.012wt%, Al 0.01-0.04wt%, N 0.004-0.012wt%, Cu 0.01-0.03wt%, Sn or Sb 0.03-0.08wt%, RE... 0.002-0.01wt%, balance being Fe and unavoidable impurities; the heating rate and atmosphere of the annealing process for high magnetic orientation electrical steel were controlled to determine the start and end temperatures of secondary recrystallization corresponding to different heating rates, enabling the high magnetic orientation electrical steel to obtain perfect secondary recrystallization and a single Gaussian texture, with a Gaussian texture orientation density value exceeding 145, and a magnetic induction intensity B8 that is 1-3% higher than that of the same grade of product. However, its hysteresis loss still needs to be further reduced.

[0006] It is evident that developing a high magnetic induction oriented electrical steel with high magnetic induction intensity, low hysteresis loss, and short production cycle, along with its annealing process, meets market demand, has broad market value and application prospects, and is of great significance to promoting the development of the oriented electrical steel field. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high magnetic induction oriented electrical steel with high magnetic induction intensity, low magnetic hysteresis loss, and short production cycle, as well as its annealing process.

[0008] To achieve the above objectives, the technical solution adopted by this invention is as follows: a high magnetic induction oriented electrical steel, with the following chemical composition by mass percentage: C: 0.03-0.045%, Si: 3.0-3.3%, Mn: 0.09-0.11%, Als: 0.025-0.035%, Nb: 0.018-0.023%, Cu: 0.09-0.11%, rare earth elements: 0.005-0.01%, V: 0.01-0.03%, B: 0.001-0.003%, Ti: 0.01-0.02%, Co: 0.5-1.0%, Ni: 0.3-0.8%, Ta: 0.005-0.015%, Hf: 0.005-0.012%, with the remainder being Fe and other unavoidable impurities.

[0009] Preferably, the rare earth elements are La, Ce, Y, and Dy mixed in a mass ratio of (3-5):1:(0.3-0.5):0.1.

[0010] Another object of the present invention is to provide an annealing process for the high magnetic induction oriented electrical steel, comprising the following steps:

[0011] Step S1, Vacuum smelting: Prepare materials according to mass percentage and smelt them in a vacuum induction furnace;

[0012] Step S2, Ultrasonic continuous casting: The casting temperature of molten steel is controlled at 1530-1550℃, the casting speed is 1.0-1.1m / min, and ultrasonic vibration of 20-30kHz is applied in the crystallizer to refine the as-cast grains to an average size of <50μm.

[0013] Step S3, Laser-assisted hot rolling: After heating the billet to a certain temperature, multi-pass hot rolling is carried out, and the surface is treated with pulsed laser before the first pass of rolling;

[0014] Step S4, gradient cold rolling: cold rolling in three passes with reduction rates of 65%, 30%, and 15% respectively, with short-time low-temperature annealing between each pass, finally rolling into a sheet with a thickness of 0.25±0.01mm;

[0015] Step S5, Two-stage decarburization annealing: In the first stage, the temperature is increased to 830-860℃ at 5-7℃ / min and held for 75-85 minutes for rapid decarburization; in the second stage, the temperature is reduced to 780-800℃, mixed gas is introduced, and the temperature is held for 50-60 minutes.

[0016] Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with nano-grade MgO-SiO2 composite release agent, place it in a strong magnetic field annealing furnace, heat it to 1190-1230℃ at 6-8℃ / min, and hold it for 15-17 hours.

[0017] Step S7, Low-temperature tempering and leveling: A four-roll leveling machine is used to level the plate after high-temperature annealing to obtain high magnetic induction oriented electrical steel.

[0018] Preferably, the smelting temperature in step S1 is 1560-1620℃.

[0019] Preferably, the specific temperature mentioned in step S3 is 1190-1230℃.

[0020] Preferably, the power density of the pulsed laser processing in step S3 is 1-3 MW / cm². 2 The scanning speed is 5-10 mm / s, and the processing time is 10-20 s.

[0021] Preferably, the low-temperature annealing temperature in step S4 is 440-510℃, and the holding time is 10-15 min.

[0022] Preferably, the mixed gas in step S5 is a mixture of hydrogen and nitrogen, wherein the volume of hydrogen accounts for 1-2% of the total volume of the mixed gas.

[0023] Preferably, the vertical magnetic field strength of the strong magnetic field annealing furnace in step S6 is 1-1.5T.

[0024] Preferably, in step S6, the mass ratio of MgO to SiO2 in the nano-scale MgO-SiO2 composite isolator is 7:3; and the coating thickness is 80-120 nm.

[0025] Preferably, the temperature of the leveling treatment in step S7 is 200-250℃, and the leveling elongation is controlled at 0.6-0.8%.

[0026] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0027] (1) The annealing process of high magnetic induction oriented electrical steel disclosed in this invention is simple and easy to implement, convenient to operate and control, and has high efficiency and high finished product qualification rate. It is suitable for continuous large-scale production and has high promotion and application value.

[0028] (2) The high magnetic induction oriented electrical steel disclosed in this invention has the following chemical composition by mass percentage: C: 0.03-0.045%, Si: 3.0-3.3%, Mn: 0.09-0.11%, Als: 0.025-0.035%, Nb: 0.018-0.023%, Cu: 0.09-0.11%, rare earth elements: 0.005-0.01%, V: 0.01-0.03%, B: 0.001-0.003%, Ti: 0.01-0.02%, Co: 0.5-1.0%, Ni: 0.3-0.8%, Ta: 0.005-0.015%, Hf: 0.005-0.012%, with the remainder being Fe and other unavoidable impurities. Through the synergistic effect of the various components, the resulting electrical steel exhibits high magnetic induction intensity, low hysteresis loss, and a short production cycle. Nb, V, Ti, Ta, and Hf are all strong carbonitride forming elements. During the solidification of molten steel and subsequent heat treatment, they form fine and dispersed carbonitrides such as NbC, VC, TiN, TaC, and HfN, respectively. These compounds effectively pin grain boundaries and inhibit abnormal grain growth during hot rolling and annealing, providing a foundation for the formation of a good Gaussian texture. Rare earth elements have a strong affinity for impurities such as S and P, preferentially combining to form high-melting-point rare earth sulfur oxides and rare earth phosphides, etc. These dispersed phases are distributed within and around grains, purifying the grain boundaries, reducing the weakening effect of impurities on the grain boundaries, and lowering the grain boundary energy. Simultaneously, rare earth atoms segregate at grain boundaries, synergistically working with boron to further reduce interfacial energy and promote grain growth in a Gaussian orientation. Co atoms have a high magnetic moment, increasing the magnetization of iron-based solid solutions. Ni reduces hysteresis loss by altering the shape of the hysteresis loop. Ni expands the austenite region, lowers the Curie point of steel, and makes the hysteresis loop narrower, thus reducing hysteresis loss. Simultaneously, the segregation of boron at grain boundaries hinders grain boundary migration, optimizes the magnetic domain structure, and further reduces the resistance to domain wall movement. The addition of copper improves the magnetism and corrosion resistance of electrical steel; the segregation of Cu atoms at grain boundaries and dislocations reduces hysteresis loss.

[0029] (3) The high magnetic induction oriented electrical steel disclosed in this invention breaks through the limitation of traditional electrical steel relying solely on conventional elements such as Si and Mn to improve performance. It introduces a variety of microalloying elements (V, B, Ti, Ta, Hf, etc.) and rare earth elements. Through the synergistic effect between the elements, the overall performance is improved, rather than simply the effect of element superposition. By rationally selecting the amount of each element added, the negative effects caused by excessive or insufficient content are avoided while ensuring that each element fully plays its role.

[0030] (4) The high magnetic induction oriented electrical steel disclosed in this invention employs a two-stage decarburization annealing process to precisely control the carbon content, creating favorable conditions for secondary recrystallization. Magnetic field-induced high-temperature annealing utilizes a strong magnetic field to drive grain growth in a directional manner. Combined with a MgO-SiO2 composite isolator applied using a specific coating process, the Gaussian texture strength is significantly improved, effectively enhancing the magnetic induction of the electrical steel. Through reasonable temperature and time control, during the magnetic field-induced high-temperature annealing process, sufficient grain growth and uniform distribution are achieved, reducing the resistance to magnetic domain wall movement and thus reducing hysteresis loss.

[0031] (5) The high magnetic orientation electrical steel disclosed in this invention introduces high-density dislocations on the surface of the sheet material through laser-assisted hot rolling, providing more nucleation points for cold rolling. Combined with gradient cold rolling and two-stage annealing, the deformation energy distribution is more uniform, promoting the competitive growth of Gaussian grains during secondary recrystallization. Magnetic field-induced annealing directly drives grain growth according to Gaussian orientation through the Lorentz force, significantly improving texture integrity and the magnetic properties of the electrical steel. Detailed Implementation

[0032] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0033] Example 1

[0034] A high magnetic orientation electrical steel, with the following chemical composition by mass percentage: C: 0.03%, Si: 3.0%, Mn: 0.09%, Als: 0.025%, Nb: 0.018%, Cu: 0.09%, rare earth elements: 0.005%, V: 0.01%, B: 0.001%, Ti: 0.01%, Co: 0.5%, Ni: 0.3%, Ta: 0.005%, Hf: 0.005%, with the remainder being Fe and other unavoidable impurities; the rare earth elements are La, Ce, Y, and Dy mixed in a mass ratio of 3:1:0.3:0.1.

[0035] An annealing process for the high magnetic induction oriented electrical steel includes the following steps:

[0036] Step S1, Vacuum smelting: Prepare materials according to mass percentage and smelt them in a vacuum induction furnace;

[0037] Step S2, Ultrasonic continuous casting: The casting temperature of molten steel is controlled at 1530℃, the casting speed is 1.0m / min, and 20kHz ultrasonic vibration is applied in the crystallizer to refine the as-cast grains to an average size of <50μm.

[0038] Step S3, Laser-assisted hot rolling: After heating the billet to a certain temperature, multi-pass hot rolling is carried out, and the surface is treated with pulsed laser before the first pass of rolling;

[0039] Step S4, gradient cold rolling: cold rolling in three passes with reduction rates of 65%, 30%, and 15% respectively, with short-time low-temperature annealing between each pass, finally rolling into a sheet with a thickness of 0.25±0.01mm;

[0040] Step S5, Two-stage decarburization annealing: In the first stage, the temperature is increased to 830℃ at 5℃ / min and held for 75 minutes for rapid decarburization; in the second stage, the temperature is reduced to 780℃, mixed gas is introduced, and the temperature is held for 50 minutes.

[0041] Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with nano-grade MgO-SiO2 composite release agent, place it in a strong magnetic field annealing furnace, heat it to 1190℃ at 6℃ / min, and hold it for 15 hours.

[0042] Step S7, Low-temperature tempering and leveling: A four-roll leveling machine is used to level the plate after high-temperature annealing to obtain high magnetic induction oriented electrical steel.

[0043] The smelting temperature in step S1 is 1560℃; the specific temperature in step S3 is 1190℃; the power density of the pulsed laser treatment in step S3 is 1MW / cm². 2 The scanning speed is 5 mm / s, and the processing time is 10 s; the low-temperature annealing temperature in step S4 is 440℃, and the holding time is 10 min; the mixed gas in step S5 is a mixture of hydrogen and nitrogen, wherein the volume of hydrogen accounts for 1% of the total volume of the mixed gas; the vertical magnetic field strength of the strong magnetic field annealing furnace in step S6 is 1 T; the mass ratio of MgO to SiO2 in the nano-scale MgO-SiO2 composite release agent in step S6 is 7:3; the coating thickness is 80 nm; the leveling treatment temperature in step S7 is 200℃, and the leveling elongation is controlled at 0.6%.

[0044] Example 2

[0045] A high magnetic orientation electrical steel, with the following chemical composition by mass percentage: C: 0.035%, Si: 3.1%, Mn: 0.095%, Als: 0.027%, Nb: 0.019%, Cu: 0.095%, rare earth elements: 0.006%, V: 0.015%, B: 0.0015%, Ti: 0.013%, Co: 0.6%, Ni: 0.4%, Ta: 0.007%, Hf: 0.007%, with the remainder being Fe and other unavoidable impurities; the rare earth elements are La, Ce, Y, and Dy mixed in a mass ratio of 3.5:1:0.35:0.1.

[0046] An annealing process for the high magnetic induction oriented electrical steel includes the following steps:

[0047] Step S1, Vacuum smelting: Prepare materials according to mass percentage and smelt them in a vacuum induction furnace;

[0048] Step S2, Ultrasonic continuous casting: The casting temperature of molten steel is controlled at 1535℃, the casting speed is 1.0m / min, and 23kHz ultrasonic vibration is applied in the crystallizer to refine the as-cast grains to an average size of <50μm.

[0049] Step S3, Laser-assisted hot rolling: After heating the billet to a certain temperature, multi-pass hot rolling is carried out, and the surface is treated with pulsed laser before the first pass of rolling;

[0050] Step S4, gradient cold rolling: cold rolling in three passes with reduction rates of 65%, 30%, and 15% respectively, with short-time low-temperature annealing between each pass, finally rolling into a sheet with a thickness of 0.25±0.01mm;

[0051] Step S5, Two-stage decarburization annealing: In the first stage, the temperature is increased to 840℃ at 5.5℃ / min and held for 77 minutes for rapid decarburization; in the second stage, the temperature is decreased to 785℃, mixed gas is introduced, and the temperature is held for 53 minutes.

[0052] Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with a nano-sized MgO-SiO2 composite release agent, place it in a strong magnetic field annealing furnace, heat it to 1200℃ at 6.5℃ / min, and hold it for 15.5 hours.

[0053] Step S7, Low-temperature tempering and leveling: A four-roll leveling machine is used to level the plate after high-temperature annealing to obtain high magnetic induction oriented electrical steel.

[0054] The smelting temperature in step S1 is 1580℃; the specific temperature in step S3 is 1200℃; the power density of the pulsed laser treatment in step S3 is 1.5MW / cm². 2 The scanning speed is 6 mm / s, and the processing time is 13 s; the low-temperature annealing temperature in step S4 is 460℃, and the holding time is 12 min; the mixed gas in step S5 is a mixture of hydrogen and nitrogen, wherein the volume of hydrogen accounts for 1.2% of the total volume of the mixed gas; the vertical magnetic field strength of the strong magnetic field annealing furnace in step S6 is 1.2 T; the mass ratio of MgO to SiO2 in the nano-scale MgO-SiO2 composite separator in step S6 is 7:3; the coating thickness is 90 nm; the leveling treatment temperature in step S7 is 210℃, and the leveling elongation is controlled at 0.65%.

[0055] Example 3

[0056] A high magnetic induction oriented electrical steel has the following chemical composition by mass percentage: C: 0.038%, Si: 3.1%, Mn: 0.1%, Als: 0.03%, Nb: 0.02%, Cu: 0.1%, rare earth elements: 0.008%, V: 0.02%, B: 0.002%, Ti: 0.015%, Co: 0.8%, Ni: 0.6%, Ta: 0.01%, Hf: 0.009%, with the remainder being Fe and other unavoidable impurities; the rare earth elements are La, Ce, Y, and Dy mixed in a mass ratio of 4:1:0.4:0.1.

[0057] An annealing process for the high magnetic induction oriented electrical steel includes the following steps:

[0058] Step S1, Vacuum smelting: Prepare materials according to mass percentage and smelt them in a vacuum induction furnace;

[0059] Step S2, Ultrasonic continuous casting: The casting temperature of molten steel is controlled at 1540℃, the casting speed is 1.1m / min, and 25kHz ultrasonic vibration is applied in the crystallizer to refine the as-cast grains to an average size of <50μm.

[0060] Step S3, Laser-assisted hot rolling: After heating the billet to a certain temperature, multi-pass hot rolling is carried out, and the surface is treated with pulsed laser before the first pass of rolling;

[0061] Step S4, gradient cold rolling: cold rolling in three passes with reduction rates of 65%, 30%, and 15% respectively, with short-time low-temperature annealing between each pass, finally rolling into a sheet with a thickness of 0.25±0.01mm;

[0062] Step S5, Two-stage decarburization annealing: In the first stage, the temperature is increased to 845℃ at 6℃ / min and held for 80 minutes for rapid decarburization; in the second stage, the temperature is reduced to 790℃, mixed gas is introduced, and the temperature is held for 55 minutes.

[0063] Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with nano-sized MgO-SiO2 composite release agent, place it in a strong magnetic field annealing furnace, heat it to 1210℃ at 7℃ / min, and hold it for 16 hours.

[0064] Step S7, Low-temperature tempering and leveling: A four-roll leveling machine is used to level the plate after high-temperature annealing to obtain high magnetic induction oriented electrical steel.

[0065] The smelting temperature in step S1 is 1590℃; the specific temperature in step S3 is 1210℃; the power density of the pulsed laser treatment in step S3 is 2MW / cm². 2The scanning speed is 8 mm / s, and the processing time is 15 s; the low-temperature annealing temperature in step S4 is 480℃, and the holding time is 13 min; the mixed gas in step S5 is a mixture of hydrogen and nitrogen, wherein the volume of hydrogen accounts for 1.5% of the total volume of the mixed gas; the vertical magnetic field strength of the strong magnetic field annealing furnace in step S6 is 1.3 T; the mass ratio of MgO to SiO2 in the nano-scale MgO-SiO2 composite separator in step S6 is 7:3; the coating thickness is 100 nm; the leveling treatment temperature in step S7 is 230℃, and the leveling elongation is controlled at 0.7%.

[0066] Example 4

[0067] A high magnetic orientation electrical steel has the following chemical composition by mass percentage: C: 0.042%, Si: 3.2%, Mn: 0.11%, Als: 0.033%, Nb: 0.022%, Cu: 0.11%, rare earth elements: 0.009%, V: 0.025%, B: 0.0025%, Ti: 0.018%, Co: 0.9%, Ni: 0.7%, Ta: 0.013%, Hf: 0.011%, with the remainder being Fe and other unavoidable impurities; the rare earth elements are La, Ce, Y, and Dy mixed in a mass ratio of 4.5:1:0.45:0.1.

[0068] An annealing process for the high magnetic induction oriented electrical steel includes the following steps:

[0069] Step S1, Vacuum smelting: Prepare materials according to mass percentage and smelt them in a vacuum induction furnace;

[0070] Step S2, Ultrasonic continuous casting: The casting temperature of molten steel is controlled at 1545℃, the casting speed is 1.1m / min, and 28kHz ultrasonic vibration is applied in the crystallizer to refine the as-cast grains to an average size of <50μm.

[0071] Step S3, Laser-assisted hot rolling: After heating the billet to a certain temperature, multi-pass hot rolling is carried out, and the surface is treated with pulsed laser before the first pass of rolling;

[0072] Step S4, gradient cold rolling: cold rolling in three passes with reduction rates of 65%, 30%, and 15% respectively, with short-time low-temperature annealing between each pass, finally rolling into a sheet with a thickness of 0.25±0.01mm;

[0073] Step S5, Two-stage decarburization annealing: In the first stage, the temperature is increased to 855℃ at 6.5℃ / min and held for 83 minutes for rapid decarburization; in the second stage, the temperature is decreased to 795℃, mixed gas is introduced, and the temperature is held for 58 minutes.

[0074] Step S6, magnetic field-induced high-temperature annealing: After coating the surface of the plate with a nano-sized MgO-SiO2 composite release agent, place it in a strong magnetic field annealing furnace, heat it to 1220℃ at 7.5℃ / min, and hold it for 16.5 hours.

[0075] Step S7, Low-temperature tempering and leveling: A four-roll leveling machine is used to level the plate after high-temperature annealing to obtain high magnetic induction oriented electrical steel.

[0076] The smelting temperature in step S1 is 1610℃; the specific temperature in step S3 is 1220℃; the power density of the pulsed laser treatment in step S3 is 2.5MW / cm². 2 The scanning speed is 9 mm / s, and the processing time is 18 s; the low-temperature annealing temperature in step S4 is 500℃, and the holding time is 14 min; the mixed gas in step S5 is a mixture of hydrogen and nitrogen, wherein the volume of hydrogen accounts for 1.8% of the total volume of the mixed gas; the vertical magnetic field strength of the strong magnetic field annealing furnace in step S6 is 1.4 T; the mass ratio of MgO to SiO2 in the nano-scale MgO-SiO2 composite separator in step S6 is 7:3; the coating thickness is 110 nm; the leveling treatment temperature in step S7 is 240℃, and the leveling elongation is controlled at 0.75%.

[0077] Example 5

[0078] A high magnetic orientation electrical steel has the following chemical composition by mass percentage: C: 0.045%, Si: 3.3%, Mn: 0.11%, Als: 0.035%, Nb: 0.023%, Cu: 0.11%, rare earth elements: 0.01%, V: 0.03%, B: 0.003%, Ti: 0.02%, Co: 1.0%, Ni: 0.8%, Ta: 0.015%, Hf: 0.012%, with the remainder being Fe and other unavoidable impurities; the rare earth elements are La, Ce, Y, and Dy mixed in a mass ratio of 5:1:0.5:0.1.

[0079] An annealing process for the high magnetic induction oriented electrical steel includes the following steps:

[0080] Step S1, Vacuum smelting: Prepare materials according to mass percentage and smelt them in a vacuum induction furnace;

[0081] Step S2, Ultrasonic continuous casting: The casting temperature of molten steel is controlled at 1550℃, the casting speed is 1.1m / min, and 30kHz ultrasonic vibration is applied in the crystallizer to refine the as-cast grains to an average size of <50μm.

[0082] Step S3, Laser-assisted hot rolling: After heating the billet to a certain temperature, multi-pass hot rolling is carried out, and the surface is treated with pulsed laser before the first pass of rolling;

[0083] Step S4, gradient cold rolling: cold rolling in three passes with reduction rates of 65%, 30%, and 15% respectively, with short-time low-temperature annealing between each pass, finally rolling into a sheet with a thickness of 0.25±0.01mm;

[0084] Step S5, Two-stage decarburization annealing: In the first stage, the temperature is increased to 860℃ at 7℃ / min and held for 85 minutes for rapid decarburization; in the second stage, the temperature is reduced to 800℃, mixed gas is introduced, and the temperature is held for 60 minutes.

[0085] Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with nano-grade MgO-SiO2 composite release agent, place it in a strong magnetic field annealing furnace, heat it to 1230℃ at 8℃ / min, and hold it for 17 hours.

[0086] Step S7, Low-temperature tempering and leveling: A four-roll leveling machine is used to level the plate after high-temperature annealing to obtain high magnetic induction oriented electrical steel.

[0087] The smelting temperature in step S1 is 1620℃; the specific temperature in step S3 is 1230℃; the power density of the pulsed laser treatment in step S3 is 3MW / cm². 2 The scanning speed is 10 mm / s, and the processing time is 20 s; the low-temperature annealing temperature in step S4 is 510℃, and the holding time is 15 min; the mixed gas in step S5 is a mixture of hydrogen and nitrogen, wherein the volume of hydrogen accounts for 2% of the total volume of the mixed gas; the vertical magnetic field strength of the strong magnetic field annealing furnace in step S6 is 1.5 T; the mass ratio of MgO to SiO2 in the nano-scale MgO-SiO2 composite separator in step S6 is 7:3; the coating thickness is 120 nm; the leveling treatment temperature in step S7 is 250℃, and the leveling elongation is controlled at 0.8%.

[0088] Comparative Example 1

[0089] This example provides a high magnetic induction oriented electrical steel and its annealing process, which is basically the same as that in Example 1. The difference is that Co and Cu are not added, and the surface is not subjected to pulsed laser treatment before the first hot rolling pass.

[0090] Comparative Example 2

[0091] This example provides a high magnetic induction oriented electrical steel and its annealing process, which is basically the same as that in Example 1. The difference is that Ta, Ni and Nb are not added, and there is no magnetic field induction during the high-temperature annealing process.

[0092] To further illustrate the beneficial technical effects of the high magnetic induction oriented electrical steel and its annealing process involved in the various embodiments of the present invention, relevant performance tests were conducted on the high magnetic induction oriented electrical steel involved in each example. The test results are shown in Table 1. The test method refers to the GB / T 3655-2008 standard, and the hysteresis loss P under the 1.7T, 50Hz condition was measured using the Epstein square. 1.7 / 50 Using a teslameter and referring to GB / T 13789-2008, the magnetic induction intensity B was measured under a magnetic field strength of 800 A / m. 800 During the testing process, the thickness of each electrical steel sample was controlled to be 0.27 mm.

[0093] Table 1. Performance test results of high magnetic induction grain-oriented electrical steel

[0094] project unit Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 B800 T 1.92 1.93 1.95 1.97 1.98 1.68 1.74 <![CDATA[P 1.7 / 50 ]]> W / kg 0.85 0.83 0.80 0.79 0.76 0.98 1.06

[0095] As can be seen from Table 1, the high magnetic induction oriented electrical steels involved in the embodiments of the present invention have higher magnetic induction intensity and lower hysteresis loss than the comparative product. The combined use of Co, Cu, Ta, Ni, Nb, laser-assisted hot rolling and magnetic field-induced high-temperature annealing is beneficial to improving the above properties.

[0096] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-magnetic-induction oriented electrical steel, characterized in that, The chemical composition by mass percentage is as follows: C: 0.03-0.045%, Si: 3.0-3.3%, Mn: 0.09-0.11%, Als: 0.025-0.035%, Nb: 0.018-0.023%, Cu: 0.09-0.11%, rare earth elements: 0.005-0.01%, V: 0.01-0.03%, B: 0.001-0.003%, Ti: 0.01-0.02%, Co: 0.5-1.0%, Ni: 0.3-0.8%, Ta: 0.005-0.015%, Hf: 0.005-0.012%, with the remainder being Fe and other unavoidable impurities.

2. The high magnetic induction oriented electrical steel according to claim 1, characterized in that, The rare earth elements are La, Ce, Y, and Dy mixed in a mass ratio of (3-5):1:(0.3-0.5):0.

1.

3. An annealing process for high magnetic induction oriented electrical steel according to any one of claims 1-2, characterized in that, Includes the following steps: Step S1, Vacuum smelting: Prepare materials according to mass percentage and smelt them in a vacuum induction furnace; Step S2, Ultrasonic continuous casting: The casting temperature of molten steel is controlled at 1530-1550℃, the casting speed is 1.0-1.1m / min, and ultrasonic vibration of 20-30kHz is applied in the crystallizer to refine the as-cast grains to an average size of <50μm. Step S3, Laser-assisted hot rolling: After heating the billet to a certain temperature, multi-pass hot rolling is carried out, and the surface is treated with pulsed laser before the first pass of rolling; Step S4, gradient cold rolling: cold rolling in three passes with reduction rates of 65%, 30%, and 15% respectively, with short-time low-temperature annealing between each pass, finally rolling into a sheet with a thickness of 0.25±0.01mm; Step S5, Two-stage decarburization annealing: In the first stage, the temperature is increased to 830-860℃ at 5-7℃ / min and held for 75-85 minutes for rapid decarburization; in the second stage, the temperature is reduced to 780-800℃, mixed gas is introduced, and the temperature is held for 50-60 minutes. Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with nano-grade MgO-SiO2 composite release agent, place it in a strong magnetic field annealing furnace, heat it to 1190-1230℃ at 6-8℃ / min, and hold it for 15-17 hours. Step S7, Low-temperature tempering and leveling: A four-roll leveling machine is used to level the plate after high-temperature annealing to obtain high magnetic induction oriented electrical steel.

4. The annealing process for high magnetic induction oriented electrical steel according to claim 3, characterized in that, The smelting temperature in step S1 is 1560-1620℃.

5. The annealing process for high magnetic induction oriented electrical steel according to claim 3, characterized in that, The specific temperature mentioned in step S3 is 1190-1230℃.

6. The annealing process for high magnetic induction oriented electrical steel according to claim 3, characterized in that, The power density of the pulsed laser processing in step S3 is 1-3 MW / cm². 2 The scanning speed is 5-10 mm / s, and the processing time is 10-20 s.

7. The annealing process for high magnetic induction oriented electrical steel according to claim 3, characterized in that, The low-temperature annealing in step S4 is performed at a temperature of 440-510℃ and a holding time of 10-15 minutes.

8. The annealing process for high magnetic induction oriented electrical steel according to claim 3, characterized in that, The mixed gas mentioned in step S5 is a mixture of hydrogen and nitrogen, wherein the volume of hydrogen accounts for 1-2% of the total volume of the mixed gas.

9. The annealing process for high magnetic induction oriented electrical steel according to claim 3, characterized in that, The vertical magnetic field strength of the strong magnetic field annealing furnace in step S6 is 1-1.5T; the mass ratio of MgO to SiO2 in the nano-scale MgO-SiO2 composite separator in step S6 is 7:3; and the coating thickness is 80-120nm.

10. The annealing process for high magnetic induction oriented electrical steel according to claim 3, characterized in that, The temperature of the leveling treatment in step S7 is 200-250℃, and the leveling elongation is controlled at 0.6-0.8%.