High-magnetic-induction oriented electrical steel and annealing process thereof

Abstract

The invention discloses high magnetic induction oriented electrical steel and an annealing process thereof, and relates to the technical field of electrical steel manufacturing, and the high magnetic induction oriented electrical steel comprises the following chemical components in percentage by mass: 0.03%-0.045% of C, 3.0%-3.3% of Si, 0.09%-0.11% of Mn, 0.025%-0.035% of Als, 0.018%-0.023% of Nb, 0.09%-0.11% of Cu, 0.005%-0.01% of rare earth elements, 0.01%-0.03% of V, 0.001%-0.003% of B, 0.01%-0.02% of Ti, 0.5%-1.0% of Co, 0.3%-0.8% of Ni, 0.005%-0.015% of Ta, 0.005%-0.012% of Hf and the balance of Fe and other inevitable impurities. The high-magnetic-induction oriented electrical steel is high in magnetic induction intensity, low in magnetic hysteresis loss and short in production period.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical steel manufacturing, in particular to a high magnetic induction oriented electrical steel and an annealing process thereof. Background Art

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

[0003] Traditional oriented electrical steel mostly relies on conventional alloying elements to regulate magnetic properties, but due to the limited synergistic effect between elements, it is difficult to break through the performance bottleneck. There are still defects such as insufficient magnetic induction intensity and excessive hysteresis loss. It cannot meet the stringent requirements of ultra-high voltage and ultra-high voltage transformers, and has a serious impact on the service life and stability of the transformer.

[0004] Existing processes for producing grain-oriented electrical steel have numerous limitations. For example, conventional annealing processes struggle to precisely control grain growth and orientation, resulting in an unsatisfactory texture and, in turn, negatively impacting magnetic properties. Furthermore, existing processes often suffer from technical drawbacks such as long production cycles and high energy consumption, hindering cost reduction and efficiency improvements.

[0005] In order to solve the above problems, the Chinese invention patent with authorization announcement number CN118272617B discloses a high magnetic induction oriented electrical steel and its annealing process, which includes, by mass percentage, 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%, with the remainder being Fe and unavoidable impurities. By controlling the heating rate and atmosphere during the annealing process of high magnetic induction oriented electrical steel and determining the start and end temperatures of secondary recrystallization corresponding to different heating rates, the high magnetic induction oriented electrical steel achieves complete secondary recrystallization and a single Gaussian texture with a Gaussian texture orientation density exceeding 145. The magnetic induction intensity B8 is 1-3% higher than that of products of the same grade. However, its hysteresis loss still needs to be further reduced.

[0006] It can be seen that the development of a high magnetic induction oriented electrical steel and its annealing process with high magnetic induction intensity, low hysteresis loss and short production cycle 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 the present invention is to overcome the deficiencies of the prior art and provide a high magnetic induction oriented electrical steel and its annealing process with high magnetic induction intensity, low hysteresis loss and short production cycle.

[0008] To achieve the above object, the technical solution adopted by the present invention is: a high magnetic induction oriented electrical steel, the chemical composition of which, 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%, and the remainder is Fe and other inevitable 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: mixing materials according to mass percentage and smelting in a vacuum induction furnace;

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

[0013] Step S3, laser-assisted hot rolling: after heating the ingot to a certain temperature, hot rolling is performed in multiple passes, and the surface is pulsed laser treated before the first rolling pass;

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

[0015] Step S5, two-stage decarburization annealing: in the first stage, the temperature is raised to 830-860°C at 5-7°C / min and kept at this temperature for 75-85 minutes for rapid decarburization; in the second stage, the temperature is lowered to 780-800°C, mixed gas is introduced, and kept at this temperature for 50-60 minutes;

[0016] Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with a nano-scale MgO-SiO2 composite isolation agent, place it in a strong magnetic field annealing furnace, raise the temperature to 1190-1230°C at 6-8°C / min, and keep it at this temperature for 15-17 hours;

[0017] Step S7, low-temperature tempering and leveling: a four-roller leveling mill 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°C.

[0019] Preferably, the certain temperature in step S3 is 1190-1230°C.

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

[0021] Preferably, the low-temperature annealing in step S4 is performed at a temperature of 440-510° C. and the holding time is 10-15 minutes.

[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 high magnetic field annealing furnace in step S6 is 1-1.5T.

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

[0025] Preferably, the temperature of the flattening treatment in step S7 is 200-250° C., and the flattening 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 for high magnetic induction oriented electrical steel disclosed in the present invention is simple and easy to operate, convenient to operate and control, high in efficiency and qualified rate of finished products, suitable for continuous large-scale production, and has high promotion and application value.

[0028] (2) The high magnetic induction oriented electrical steel disclosed in the present invention has the following chemical composition, calculated 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%, and the remainder is Fe and other inevitable impurities. Through the mutual cooperation between the various components, the produced electrical steel has 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 steel solidification and subsequent heat treatment, they form fine, dispersed carbonitrides such as NbC, VC, TiN, TaC, and HfN, respectively. These compounds effectively pin grain boundaries during hot rolling and annealing, inhibiting abnormal grain growth and providing the foundation for the formation of a well-defined Gaussian texture. Rare earth elements have a strong affinity for impurities such as S and P, preferentially combining to form dispersed phases such as high-melting-point rare earth oxysulfides and rare earth phosphides. These dispersed phases are distributed at grain boundaries and within grains, purifying them and reducing impurity weakening, thereby lowering the grain boundary energy. Furthermore, rare earth atoms segregate at grain boundaries, synergizing with boron to further reduce interfacial energy and promote Gaussian grain growth. Co atoms, with their high magnetic moment, can increase the magnetization of iron-based solid solutions. Ni reduces hysteresis losses 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, thereby reducing hysteresis losses. Furthermore, the concentration 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 magnetic properties and corrosion resistance of electrical steel. Cu atoms concentrate at grain boundaries and dislocations, reducing hysteresis losses.

[0029] (3) The chemical composition of the high magnetic induction oriented electrical steel disclosed in the present invention breaks through the limitation of traditional electrical steel that relies only on conventional elements such as Si and Mn to improve performance, and introduces a variety of micro-alloying elements (V, B, Ti, Ta, Hf, etc.) and rare earth elements; through the synergistic effect between the elements, a comprehensive improvement in performance is achieved, rather than a simple element superposition effect; through the reasonable selection of the addition amount of each element, while ensuring that each element fully exerts its own role, the negative impact caused by excessively high or low content is avoided.

[0030] (4) The high magnetic induction oriented electrical steel disclosed in the present invention utilizes a two-stage decarburization annealing process to precisely control the carbon content, creating favorable conditions for secondary recrystallization. A magnetic field-induced high-temperature annealing process utilizes a strong magnetic field to drive grain growth in a directional manner. Combined with a MgO-SiO2 composite separator using a specific coating process, this significantly enhances the Gaussian texture strength and effectively improves the magnetic induction strength of the electrical steel. Through reasonable temperature and time control, the magnetic field-induced high-temperature annealing process achieves full grain growth and uniform distribution, reducing the resistance to magnetic domain wall movement and thereby reducing hysteresis losses.

[0031] (5) The high magnetic induction oriented electrical steel disclosed in the present invention uses laser-assisted hot rolling to introduce a high density of dislocations on the plate surface, providing more nucleation sites for cold rolling. Combined with gradient cold rolling and two-stage annealing, this results in a more uniform distribution of deformation energy storage, promoting the competitive growth of Gaussian grains during secondary recrystallization. Magnetic field-induced annealing, through the Lorentz force, directly drives grain growth in a Gaussian orientation, significantly improving the texture integrity and magnetic properties of the electrical steel. DETAILED DESCRIPTION

[0032] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.

[0033] Example 1

[0034] A high magnetic induction oriented electrical steel has the following chemical composition, calculated 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%, and the remainder is Fe and other inevitable 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 comprises the following steps:

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

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

[0038] Step S3, laser-assisted hot rolling: after heating the ingot to a certain temperature, hot rolling is performed in multiple passes, and the surface is pulsed laser treated before the first rolling pass;

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

[0040] Step S5, two-stage decarburization annealing: in the first stage, the temperature is raised to 830°C at 5°C / min and kept at this temperature for 75 minutes for rapid decarburization; in the second stage, the temperature is lowered to 780°C, mixed gas is introduced, and kept at this temperature for 50 minutes;

[0041] Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with a nano-scale MgO-SiO2 composite isolation agent, place it in a strong magnetic field annealing furnace, increase the temperature to 1190°C at 6°C / min, and keep it at this temperature for 15 hours;

[0042] Step S7, low-temperature tempering and leveling: a four-roller leveling mill 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°C; the certain temperature in step S3 is 1190°C; the power density of the pulse laser treatment in step S3 is 1MW / cm 2 , the scanning speed is 5mm / s, and the processing time is 10s; the temperature of the low-temperature annealing in step S4 is 440°C, and the holding time is 10min; 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 high magnetic field annealing furnace in step S6 is 1T; the mass ratio of MgO to SiO2 in the nano-scale MgO-SiO2 composite isolation agent in step S6 is 7:3; the coating thickness is 80nm; the temperature of the leveling treatment in step S7 is 200°C, and the leveling elongation is controlled at 0.6%.

[0044] Example 2

[0045] A high magnetic induction oriented electrical steel has the following chemical composition, calculated 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%, and the remainder is Fe and other inevitable 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 comprises the following steps:

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

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

[0049] Step S3, laser-assisted hot rolling: after heating the ingot to a certain temperature, hot rolling is performed in multiple passes, and the surface is pulsed laser treated before the first rolling pass;

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

[0051] Step S5, two-stage decarburization annealing: in the first stage, the temperature is raised to 840°C at 5.5°C / min and kept at this temperature for 77 minutes for rapid decarburization; in the second stage, the temperature is lowered to 785°C, mixed gas is introduced, and kept at this temperature for 53 minutes;

[0052] Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with a nano-scale MgO-SiO2 composite isolation agent, place it in a strong magnetic field annealing furnace, increase the temperature to 1200°C at 6.5°C / min, and keep it at this temperature for 15.5 hours;

[0053] Step S7, low-temperature tempering and leveling: a four-roller leveling mill 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°C; the certain temperature in step S3 is 1200°C; the power density of the pulse laser treatment in step S3 is 1.5MW / cm 2 , the scanning speed is 6mm / s, and the processing time is 13s; the temperature of the low-temperature annealing in step S4 is 460°C, and the holding time is 12min; 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 high magnetic field annealing furnace in step S6 is 1.2T; the mass ratio of MgO to SiO2 in the nano-scale MgO-SiO2 composite isolation agent in step S6 is 7:3; the coating thickness is 90nm; the temperature of the leveling treatment in step S7 is 210°C, 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, calculated 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%, and the remainder is Fe and other inevitable 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 comprises the following steps:

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

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

[0060] Step S3, laser-assisted hot rolling: after heating the ingot to a certain temperature, hot rolling is performed in multiple passes, and the surface is pulsed laser treated before the first rolling pass;

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

[0062] Step S5, two-stage decarburization annealing: in the first stage, the temperature is raised to 845°C at 6°C / min and kept at this temperature for 80 minutes for rapid decarburization; in the second stage, the temperature is lowered to 790°C, mixed gas is introduced, and kept at this temperature for 55 minutes;

[0063] Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with a nano-scale MgO-SiO2 composite isolation agent, place it in a strong magnetic field annealing furnace, increase the temperature to 1210°C at 7°C / min, and keep it at this temperature for 16 hours;

[0064] Step S7, low-temperature tempering and leveling: a four-roller leveling mill 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°C; the certain temperature in step S3 is 1210°C; the power density of the pulse laser treatment in step S3 is 2MW / cm 2, the scanning speed is 8 mm / s, and the processing time is 15 s; the temperature of the low-temperature annealing in step S4 is 480°C, 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 high 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 isolation agent in step S6 is 7:3; the coating thickness is 100 nm; the temperature of the leveling treatment in step S7 is 230°C, and the leveling elongation is controlled at 0.7%.

[0066] Example 4

[0067] A high magnetic induction oriented electrical steel has the following chemical composition, calculated 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%, and the remainder is Fe and other inevitable 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 comprises the following steps:

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

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

[0071] Step S3, laser-assisted hot rolling: after heating the ingot to a certain temperature, hot rolling is performed in multiple passes, and the surface is pulsed laser treated before the first rolling pass;

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

[0073] Step S5, two-stage decarburization annealing: in the first stage, the temperature is raised to 855°C at 6.5°C / min and kept at this temperature for 83 minutes for rapid decarburization; in the second stage, the temperature is lowered to 795°C, mixed gas is introduced, and kept at this temperature for 58 minutes;

[0074] Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with a nano-scale MgO-SiO2 composite isolation agent, place it in a strong magnetic field annealing furnace, increase the temperature to 1220°C at 7.5°C / min, and keep it at this temperature for 16.5 hours;

[0075] Step S7, low-temperature tempering and leveling: a four-roller leveling mill 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°C; the certain temperature in step S3 is 1220°C; the power density of the pulse laser treatment in step S3 is 2.5MW / cm 2 , the scanning speed is 9 mm / s, and the processing time is 18 s; the temperature of the low-temperature annealing in step S4 is 500°C, 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 high 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 isolation agent in step S6 is 7:3; the coating thickness is 110 nm; the temperature of the leveling treatment in step S7 is 240°C, and the leveling elongation is controlled at 0.75%.

[0077] Example 5

[0078] A high magnetic induction oriented electrical steel has the following chemical composition, calculated 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%, and the remainder is Fe and other inevitable 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 comprises the following steps:

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

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

[0082] Step S3, laser-assisted hot rolling: after heating the ingot to a certain temperature, hot rolling is performed in multiple passes, and the surface is pulsed laser treated before the first rolling pass;

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

[0084] Step S5, two-stage decarburization annealing: in the first stage, the temperature is raised to 860°C at 7°C / min and kept at this temperature for 85 minutes for rapid decarburization; in the second stage, the temperature is lowered to 800°C, mixed gas is introduced, and kept at this temperature for 60 minutes;

[0085] Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with a nano-scale MgO-SiO2 composite isolation agent, place it in a strong magnetic field annealing furnace, increase the temperature to 1230°C at 8°C / min, and keep it at this temperature for 17 hours;

[0086] Step S7, low-temperature tempering and leveling: a four-roller leveling mill 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°C; the certain temperature in step S3 is 1230°C; the power density of the pulse laser treatment in step S3 is 3MW / cm 2 , the scanning speed is 10mm / s, and the processing time is 20s; the temperature of the low-temperature annealing in step S4 is 510℃, and the holding time is 15min; 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 high magnetic field annealing furnace in step S6 is 1.5T; the mass ratio of MgO to SiO2 in the nano-scale MgO-SiO2 composite isolation agent in step S6 is 7:3; the coating thickness is 120nm; the temperature of the leveling treatment 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 Example 1, except that Co and Cu are not added, and the surface is not pulsed laser treated 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 Example 1, except that Ta, Ni and Nb are not added, and there is no magnetic field induction during the high temperature annealing process.

[0092] In order to further illustrate the beneficial technical effects of the high magnetic induction oriented electrical steel and its annealing process involved in each embodiment 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 Epstein square ring is used to measure the hysteresis loss P under 1.7T and 50Hz working conditions. 1.7 / 50 , using Tesla meter, refer to GB / T 13789-2008, measure magnetic induction intensity B under magnetic field intensity of 800A / m 800 During the test, the thickness of each electrical steel sample was controlled to be 0.27 mm.

[0093] Table 1 Performance test results of high magnetic induction 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 according to the embodiments of the present invention have higher magnetic induction intensity and lower hysteresis loss than the comparative products. 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 people familiar with this technology to understand the content of the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in 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%, and the rest is Fe and other inevitable 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 to 2, characterized in that: The steps include: Step S1, vacuum smelting: mixing materials according to mass percentage and smelting in a vacuum induction furnace; Step S2, ultrasonic continuous casting: the molten steel casting temperature is controlled at 1530-1550°C, the casting speed is 1.0-1.1 m / min, and 20-30 kHz ultrasonic vibration is applied in the crystallizer to refine the as-cast grains to an average size of less than 50 μm; Step S3, laser-assisted hot rolling: after heating the ingot to a certain temperature, hot rolling is performed in multiple passes, and the surface is pulsed laser treated before the first rolling pass; Step S4, gradient cold rolling: cold rolling in three passes with reduction rates of 65%, 30%, and 15%, respectively, with short low-temperature annealing between each pass, and finally rolling into a plate with a thickness of 0.25±0.01 mm; Step S5, two-stage decarburization annealing: in the first stage, the temperature is raised to 830-860°C at 5-7°C / min and kept at this temperature for 75-85 minutes for rapid decarburization; in the second stage, the temperature is lowered to 780-800°C, mixed gas is introduced, and kept at this temperature for 50-60 minutes; Step S6, magnetic field induced high temperature annealing: After coating the surface of the plate with a nano-scale MgO-SiO2 composite isolation agent, place it in a strong magnetic field annealing furnace, raise the temperature to 1190-1230°C at 6-8°C / min, and keep it at this temperature for 15-17 hours; Step S7, low-temperature tempering and leveling: a four-roller leveling mill 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°C.

5. The annealing process for high magnetic induction oriented electrical steel according to claim 3, characterized in that: The certain temperature in step S3 is 1190-1230°C.

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

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° C. 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 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 high magnetic field annealing furnace in step S6 is 1-1.5 T; the mass ratio of MgO to SiO2 in the nano-scale MgO-SiO2 composite isolation agent in step S6 is 7:3; and the coating thickness is 80-120 nm.

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