B800 > 1.93 T magnesium silicate bottom layer-free ultrahigh magnetic induction oriented silicon steel prepared by laser process and method

Abstract

The invention discloses ultrahigh magnetic induction oriented silicon steel prepared by a laser process and having B800 greater than 1.93 T and without a magnesium silicate bottom layer and a method. The ultrahigh magnetic induction oriented silicon comprises the following components in percentage by weight: 0.015-0.095% of C, 2.50-4.50% of Si, 0.010-0.040% of Als, 0.0050-0.0100% of N, 0.010-1.00% of Mn, 0.0030-0.0300% of S, and compound addition of any at least two of P, Cu, Sn, Bi, Sb, Cr and As, wherein (P + Cu + Sn + Bi + Sb + Cr + As) is less than or equal to 1.80%; the preparation method comprises the following steps: smelting, carrying out vacuum treatment and casting into a blank; heating the casting blank; hot rolling; performing coiling; normalizing is conducted; performing primary cold rolling; carrying out decarburization annealing; nitriding treatment is carried out; coating a conventional high-temperature annealing isolating agent which takes MgO as a main component; performing high-temperature annealing; uncoiling and carrying out laser treatment under a protective atmosphere; and stretching, flattening and annealing. The finished product is excellent in magnetic performance, the magnetic induction B800 is larger than or equal to 1.93 T, P17 / 50 is smaller than or equal to 1.25 W / kg, the stamping machining and welding performance of the finished product is excellent, no magnesium silicate bottom layer exists on the whole plate face, and the smoothness of the plate face can be improved to 100%.

Description

Technical Field

[0001] The present invention relates to an oriented electrical steel and a production method thereof, and particularly belongs to a method for preparing a non-magnesium silicate bottom layer ultra-high magnetic induction oriented electrical steel with B 800 > 1.93T without a magnesium silicate bottom layer and a method therefor. Background Art

[0002] Oriented electrical steel is mainly used as the core of a transformer and is the "heart" material of various power transmission and transformation transformers. It is an important soft magnetic alloy indispensable in the power and electronics industries. The quality grade of oriented electrical steel plays a decisive role in the development of the national power industry. Oriented electrical steel is regarded as an important symbol of the steel manufacturing technology level because of its most complex manufacturing process, high technical content, and high added value. Oriented electrical steel can be divided into ordinary oriented electrical steel (CGO) and high magnetic steel oriented electrical steel (HiB) according to the manufacturing process and magnetic induction. Typically, ordinary oriented electrical steel is the oriented electrical steel developed by the Upper Iset and Novolipetsk Steel Works in Russia, etc., with Cu2S as the main inhibitor. Typically, high magnetic induction oriented electrical steel is the high magnetic induction oriented electrical steel (HiB) with higher magnetic induction and lower iron loss first produced by Nippon Steel using the single large reduction cold rolling method, with AlN as the main and MnS as the auxiliary inhibitor. Later, the Yawata Works of Nippon Steel first proposed not to use the AlN precipitated before decarburization annealing as an inhibitor, that is, not to use the "inherent inhibitor", but to carry out nitriding treatment after decarburization annealing to form an inhibitor with N and Als in the steel, that is, to rely on the inhibitor obtained in the subsequent process, which can reduce the slab heating temperature to 1150-1200°C. Energy conservation and environmental protection have become a global trend today. At the same time, with the large-scale power construction in China, the domestic demand for oriented electrical steel is increasing, and there is a huge market space. Therefore, the development of high-performance oriented electrical steel is becoming more and more urgent, and higher magnetic induction and lower iron loss have always been the pursuit and goal of oriented electrical steel production.

[0003] Most of the wind power motors, thermal power motors, and nuclear power motors at home and abroad use high-grade non-oriented electrical steel. However, in recent years, with the rapid development of the motor industry, in order to further improve the efficiency of the motor, some users have improved the design and selected high magnetic polarization intensity oriented electrical steel as the main material for the core or other components. At the same time, in addition to meeting excellent electromagnetic performance, in order to meet the requirements of punching processing, it is required that the surface of the oriented electrical steel sheet used for large motors has no magnesium silicate bottom layer. However, when used as the main material for the core, an insulating isolation coating still needs to be applied to meet insulation, adhesion, low surface hardness, etc., and when used for other components, the surface of the steel sheet needs to be completely without a magnesium silicate bottom layer to ensure excellent welding performance. At the same time, the finished product of non-magnesium silicate bottom layer oriented electrical steel without an insulating coating can be used as the base material for preparing an ultra-thin strip of oriented electrical steel with a thickness of 0.03-0.10 mm.

[0004] After retrieval:

[0005] The document with the Chinese patent application number CN109112395A discloses "A Non-bottom-oriented Ultra-thin Strip Base Material and Its Preparation Method". The raw material components of the base material are C 0.035 - 0.075%, Si 2.8% - 3.4%, Cu 0.20 - 0.45%, Sn 0.1 - 0.2%, Als 0.02% - 0.03%, S 0.015 - 0.03%, Mn 0.04 - 0.08%, N 0.005 - 0.01%, Sb 0.03 - 0.09%, and the balance is Fe. The preparation method includes continuous casting, hot rolling, normalizing, pickling, cold rolling, decarburizing annealing, coating an isolation layer (such as Al2O3, SiO2, etc.), high-temperature annealing, etc. to obtain a non-magnesium silicate bottom-oriented silicon steel base material that can be directly used for the preparation of oriented silicon steel ultra-thin strips without pickling. Although this document can obtain oriented silicon steel without forming a magnesium silicate bottom layer, due to the presence of Al2O3, SiO2, etc. in the isolation coating (which destroys the formation of the magnesium silicate bottom layer), the inhibitor is unstable during the high-temperature annealing process, resulting in unstable magnetic properties of the finished product and it is difficult to obtain a non-magnesium silicate bottom-oriented silicon steel with a smooth surface across the entire plate.

[0006] The document with the Chinese patent application number CN113215374A discloses "A Preparation Method of Non-bottom-oriented Silicon Steel", which includes production steps such as pickling of hot-rolled billets, cold rolling, decarburizing annealing, coating an isolation agent, high-temperature annealing, stretch leveling, laser removal of the magnesium silicate bottom layer, stress relief annealing, etc. This invention uses a laser method to prepare non-bottom-oriented silicon steel, replacing the traditional method of removing the magnesium silicate bottom layer by acid or adding special additives (such as Al2O3, SiO2, etc.) in the MgO coating solution. The prepared oriented silicon steel strip has a bright surface and does not contain a magnesium silicate bottom layer. However, this document requires a stress relief annealing process after laser removal of the magnesium silicate bottom layer. The process is as follows: the protective atmosphere for stress relief annealing needs to be heated to 600 - 800°C, the protective atmosphere is a mixed gas of hydrogen and nitrogen with a volume ratio of 1 - 3:1, the flow rate is 3 - 10 Nm 3 / h, and the annealing holding time is 1 - 10 h. This undoubtedly increases the preparation process (and related equipment), significantly increases the manufacturing cost of non-bottom-oriented silicon steel, and does not disclose its electromagnetic properties. Only the electromagnetic properties of the 0.03 - 0.10 mm thick oriented silicon steel ultra-thin strip prepared with this non-bottom-oriented silicon steel as the base material are disclosed.

[0007] It can be seen that in the above-mentioned documents such as CN109112395A, during the process of coating the MgO coating solution in the preparation process of grain-oriented electrical steel, special additives (such as Al2O3, SiO2, etc.) are added to the MgO coating solution to achieve the effect of removing the magnesium silicate bottom layer. However, such traditional processes for preparing grain-oriented electrical steel without a magnesium silicate bottom layer will cause instability of the inhibitor during high-temperature annealing, resulting in unstable magnetic properties of the finished grain-oriented electrical steel, and it is difficult to obtain grain-oriented electrical steel without a magnesium silicate bottom layer with a smooth surface across the entire plate (it cannot meet the requirements of having no magnesium silicate bottom layer on the surface of some components of large motor cores and excellent weldability); another type of document such as CN113215374A prepares grain-oriented electrical steel without a bottom layer through a laser process, replacing the traditional method of removing the magnesium silicate bottom layer of grain-oriented electrical steel. However, this document requires a stress-relieving annealing process after laser removal of the magnesium silicate bottom layer (the protective atmosphere for stress-relieving annealing needs to be heated to 600 - 800 °C, the protective atmosphere is a mixture of hydrogen and nitrogen with a volume ratio of 1 - 3:1, the flow rate is 3 - 10 Nm 3 / h, and the annealing holding time is 1 - 10 h), resulting in too high manufacturing costs for grain-oriented electrical steel without a magnesium silicate bottom layer, and its electromagnetic properties are not disclosed. Summary of the Invention

[0008] The present invention aims to overcome the deficiencies existing in the prior art and provides a kind of B 800 ≥1.93 T, P 17 / 50 ≤1.25 W / kg, and provides a method for preparing ultra-high magnetic induction grain-oriented electrical steel without a magnesium silicate bottom layer across the entire plate using a laser process.

[0009] Measures to achieve the above object:

[0010] A kind of B prepared by a laser process 800 > 1.93 T ultra-high magnetic induction grain-oriented electrical steel without a magnesium silicate bottom layer, which is characterized in that: the component composition and weight percentage content of the ultra-high magnetic induction grain-oriented silicon are: C: 0.015 - 0.095%, Si: 2.50 - 4.50%, Als: 0.010 - 0.040%, N: 0.0050 - 0.0100%, Mn: 0.010 - 1.00%, S: 0.0030 - 0.0300%, any at least two of P, Cu, Sn, Bi, Sb, Cr and As are added in combination and satisfy (P + Cu + Sn + Bi + Sb + Cr + As) ≤ 1.80%, and the rest are iron and inevitable impurities.

[0011] A method for preparing B 800 > 1.93 T ultra-high magnetic induction grain-oriented electrical steel without a magnesium silicate bottom layer by a laser process, and its steps are as follows:

[0012] 1) After smelting, vacuum treatment, and casting into a billet;

[0013] 2) Heat the continuous casting billet, with the heating temperature controlled at 1100 - 1400 °C;

[0014] 3) Conduct hot rolling, control the finish rolling temperature at 850 - 1100 °C, and control the thickness of the hot rolled sheet at 2.0 - 2.8 mm;

[0015] 4) Conduct coiling, control the coiling temperature not exceeding 600 °C;

[0016] 5) Conduct normalizing, control the normalizing temperature at 1000 - 1150 °C, and hold at this temperature for 30 - 180 s;

[0017] 6) Conduct first - stage cold rolling, perform at least one pass of aging rolling during cold rolling, control the aging temperature at 160 - 250 °C, and the finished product thickness at 0.15 - 0.35 mm;

[0018] 7) Conduct decarburization annealing under a wet protective atmosphere, control the decarburization annealing temperature at 750 - 900 °C, hold at this temperature for 60 - 180 s, and the dew point is 25 °C; the protective atmosphere is a mixed gas of wet H2 and N2, where the volume content of H2 is 15 - 80%;

[0019] 8) Conduct nitriding treatment:

[0020] When the heating temperature of the continuous casting billet is not lower than 1260 °C, nitriding is not required;

[0021] When the heating temperature of the continuous casting billet is lower than 1260 °C, nitriding is required. The nitriding atmosphere is a mixed gas of wet H2, N2 and NH3, where the volume content of H2 is 15 - 80%; and control the nitrogen infiltration amount at 50 - 350 ppm;

[0022] 9) Coat a conventional high - temperature annealing release agent with MgO as the main component;

[0023] 10) Conduct conventional high - temperature annealing;

[0024] 11) Uncoil and conduct laser treatment under a protective atmosphere:

[0025] Laser treatment parameters: The average power of the continuous laser is 20 - 3500 W; the laser pulse repetition frequency is 1 -

[0026] 160 kHz; the laser pulse width is 1 - 10 ms; the filling line spacing is 0.01 - 0.06 mm; the scanning rate is

[0027] 10 - 8000 mm / s; the focus of the light beam is focused on the surface of the steel plate; the protective gas is nitrogen or argon, and the protective gas flow

[0028] rate is 1 - 50 L / min;

[0029] 12) Perform conventional stretch leveling annealing treatment on the steel strip.

[0030] Preferably: the average power of the continuous laser is 50 - 3350 W.

[0031] Preferably: the laser pulse repetition frequency is 3 - 150 kHz.

[0032] Preferably: the filling wire spacing is 0.02 - 0.05 mm.

[0033] Preferably: the scanning rate is 25 - 7800 mm / s.

[0034] Preferably: the laser pulse width is 2 - 8.5 ms.

[0035] Functions and mechanisms of the main processes in the present invention

[0036] The reason for controlling the heating temperature of the slab at 1100°C ≤ ST ≤ 1400°C in the present invention is to ensure hot rolling within a relatively high temperature range and a relatively high final rolling temperature, so that no large - sized second - phase particles such as AlN precipitate during hot rolling.

[0037] The reason for controlling the normalizing temperature at 1000 - 1150°C and holding for 30 - 180 s at this temperature in the present invention is to ensure that AlN second - phase particles with appropriate sizes complete solid solution to form (or form during nitriding treatment) favorable second phases. When normalizing at temperatures below 1000°C, due to the low temperature, AlN is difficult to solidify; when higher than 1150°C, the grains of the steel strip coarsen, resulting in grain growth after primary recrystallization annealing and increasing costs at the same time.

[0038] The reason for controlling at least one pass of aging rolling at 160 - 250°C during cold rolling in the present invention is that cold rolling aging can increase the content of dissolved carbon and nitrogen in the steel. During cold rolling, the dissolved carbon and nitrogen accumulate at dislocations, hinder dislocation movement, change the normal slip system, promote the formation of more transition zones, and form more favorable primary recrystallization texture components after cold rolling and annealing.

[0039] The reason for controlling the decarburizing annealing temperature at 750 - 900°C and holding for 60 - 180 s at this temperature in the present invention is to complete primary recrystallization, so that there are sufficient numbers of

[110] (001) grains (secondary nuclei) in the matrix and a primary recrystallization structure and texture conducive to their growth; reduce the carbon in the steel to below 0.0030% to ensure a single α - phase during subsequent high - temperature annealing; and form a dense and uniform SiO2 film on the surface of the steel strip.

[0040] When the heating temperature of the continuous casting billet is controlled at 1100 - 1260°C in the present invention, nitriding treatment must be carried out in the subsequent processes. When the heating temperature is 1260 - 1400°C, nitriding treatment is not required in the subsequent processes. This is because when the heating temperature of the continuous casting billet is 1100 - 1260°C, only part of the AlN in the billet can be dissolved, and nitriding treatment must be carried out in the annealing process to increase the content of AlN second-phase particles, ensuring sufficient inhibitory force to obtain a perfect secondary recrystallization structure and texture. When the heating temperature is 1260 - 1400°C, the AlN in the billet can be completely and fully dissolved, and a sufficient amount of AlN second-phase particles can be obtained in the normalizing and annealing processes of the hot-rolled sheet, ensuring sufficient inhibitory force to obtain a perfect secondary recrystallization structure and texture. Therefore, nitriding treatment is not required.

[0041] The purpose of nitriding treatment is to ensure that there is sufficient nitrogen content in the steel to form AlN and (Si,Al)N, forming a favorable second phase, inhibiting the normal growth of primary grains during high-temperature annealing, and promoting the perfection of secondary recrystallization.

[0042] In the present invention, a high-temperature annealing release agent with MgO as the main component is coated to play a role in isolating the layers of the steel coil during high-temperature annealing.

[0043] When the laser treatment parameters are controlled in the present invention: the average power of the continuous laser is 20 - 3500 W; the laser pulse repetition frequency is 1 - 160 kHz; the laser pulse width is 1 - 10 ms; the filling line spacing is 0.01 - 0.06 mm; the scanning speed is 10 - 8000 mm / s; the focus of the beam is focused on the surface of the steel plate; the protective gas is nitrogen or argon, and the flow rate of the protective gas is 1 - 50 L / min. This is based on the difference in the damage threshold between the magnesium silicate bottom layer and the substrate. Through processes such as precise ablation of the magnesium silicate bottom layer by high-energy pulsed laser, rapid galvanometer scanning, purging with protective gas, and filtering with a smoke absorber, the removal of the magnesium silicate bottom layer with low damage and smooth full plate surface on the grain-oriented silicon steel surface is achieved. Its feature is that the position of the galvanometer can be adjusted longitudinally to make the focus of the beam focus on the surface of the steel plate, achieving high efficiency in removing the magnesium silicate bottom layer, easy automation control, and the effect of a smooth full plate surface. Then, through the tension leveling annealing treatment of the steel strip, a finished product of grain-oriented silicon steel with a smooth full plate surface and no magnesium silicate bottom layer and ultra-high magnetic induction is obtained.

[0044] However, when the average power of the laser is lower than 20W, incomplete removal of the magnesium silicate bottom layer of the final product will occur, and full-surface smoothness cannot be achieved (poor steel plate stamping processability and weldability); when the average power of the laser is higher than 3500W, local heating of the steel strip will cause plastic deformation, resulting in poor plate shape; when the laser pulse repetition frequency is lower than 1kHz, incomplete removal of the magnesium silicate bottom layer of the final product will occur, and full-surface smoothness cannot be achieved (poor steel plate stamping processability and weldability); when the average power of the laser is higher than 160kHz, local heating of the steel strip will cause plastic deformation, resulting in poor plate shape; when the laser pulse width is lower than 1ms, incomplete removal of the magnesium silicate bottom layer of the final product will occur, and full-surface smoothness cannot be achieved (poor steel plate stamping processability and weldability); when the laser pulse width is higher than 10ms, local heating of the steel strip will cause plastic deformation, resulting in poor plate shape; when the laser pulse filling line spacing is lower than 0.01mm, local heating of the steel strip will cause plastic deformation, resulting in poor plate shape; when the laser filling line spacing is higher than 0.06mm, incomplete removal of the magnesium silicate bottom layer of the final product will occur, and full-surface smoothness cannot be achieved (poor steel plate stamping processability and weldability); when the laser scanning rate is lower than 10mm / s, incomplete removal of the magnesium silicate bottom layer of the final product will occur, and full-surface smoothness cannot be achieved (poor steel plate stamping processability and weldability); when the laser scanning rate is higher than 8000mm / s, local heating of the steel strip will cause plastic deformation, resulting in poor plate shape.

[0045] Compared with the prior art, the finished product of the present invention has excellent magnetic properties, magnetic induction B 800 ≥1.93T, P 17 / 50 ≤1.25W / kg, the finished product has excellent stamping processability and weldability, there is no magnesium silicate bottom layer on the full surface, and the surface smoothness can be increased to 100%. Specific embodiments

[0046] The present invention will be described in detail below:

[0047] Table 1 is a list of chemical components of each embodiment and comparative example of the present invention;

[0048] Table 2 is a list of main process values of each embodiment and comparative example of the present invention;

[0049] Table 3 is a list of performance detections of each embodiment and comparative example of the present invention.

[0050] Each embodiment of the present invention is produced according to the following steps:

[0051] 1) After smelting, vacuum treatment, and casting into billets;

[0052] 2) Heating the cast billet, and controlling the heating temperature at 1100 - 1400°C;

[0053] 3) Carry out hot rolling, control the finish rolling temperature at 850 - 1100 °C, and control the thickness of the hot rolled sheet at 2.0 - 2.8 mm;

[0054] 4) Carry out coiling, control the coiling temperature not exceeding 600 °C;

[0055] 5) Carry out normalizing, control the normalizing temperature at 1000 - 1150 °C, and hold at this temperature for 30 - 180 s;

[0056] 6) Carry out first cold rolling, perform at least one pass of aging rolling during cold rolling, control the aging temperature at 160 - 250 °C, and the finished product thickness at 0.15 - 0.35 mm;

[0057] 7) Carry out decarburization annealing under a wet protective atmosphere, control the decarburization annealing temperature at 750 - 900 °C, and hold at this temperature for 60 - 180 s, with a dew point of 25 °C; the protective atmosphere is a mixed gas of wet H2 and N2, where the volume content of H2 is 15 - 80%;

[0058] 8) Carry out nitriding treatment:

[0059] When the heating temperature of the continuous casting billet is not lower than 1260 °C, nitriding is not required;

[0060] When the heating temperature of the continuous casting billet is lower than 1260 °C, nitriding is required. The nitriding atmosphere is a mixed gas of wet H2, N2 and NH3, where the volume content of H2 is 15 - 80%, and control the amount of infiltrated nitrogen at 50 - 350 ppm;

[0061] 9) Coat with a conventional high - temperature annealing release agent mainly composed of MgO;

[0062] 10) Carry out conventional high - temperature annealing;

[0063] 11) Uncoil and carry out laser treatment under a protective atmosphere:

[0064] Laser treatment parameters: The average power of the continuous laser is 20 - 3500 W; the laser pulse repetition frequency is 1 -

[0065] 160 kHz; the laser pulse width is 1 - 10 ms; the filling line spacing is 0.01 - 0.06 mm; the scanning rate is

[0066] 10 - 8000 mm / s; the focus of the light beam is focused on the surface of the steel plate; the protective gas is nitrogen or argon, and the protective gas flow

[0067] rate is 1 - 50 L / min;

[0068] 12) Carry out conventional tension leveling annealing treatment on the steel strip.

[0069] Note: The high-temperature annealing release agent is a conventional release agent mainly composed of MgO.

[0070] Table 1 Value list of each embodiment and comparative example of the present invention (wt%)

[0071]

[0072]

[0073] As can be seen from Table 1, in Comparative Example Q1, Als < 0.010%, the Als content is low, the number of AlN precipitates decreases after decarburization (nitriding), the inhibitory force during high-temperature annealing decreases, and the finished product magnetic properties decrease; in Comparative Example Q2, Als > 0.040%, the solubility product of Als and N is relatively high, and it is difficult to completely dissolve during heating at 1100 - 1400 °C, resulting in a decrease in the effective precipitation quantity after decarburization (nitriding), thereby causing a decrease in the inhibitory force during high-temperature annealing and a decrease in the finished product magnetic properties; in Comparative Example Q3, (P + Cu + Sn + Bi + Sb + Cr + As) > 1.80%, the content of interfacial enrichment elements is too high, and the hot-rolled edge cracking is extremely large, making it difficult to carry out production smoothly.

[0074] Table 2 List of main process parameters of each embodiment and comparative example of the present invention

[0075]

[0076]

[0077] Continued Table 2

[0078]

[0079] Note: The protective gas in Table 2 is nitrogen or argon, and the two can be interchanged.

[0080] As can be seen from Table 2:

[0081] In comparative example Q1, the slab hot rolling heating temperature is less than 1100°C, the final rolling temperature is less than 850°C, AlN cannot be completely dissolved during the heating process, and the final rolling temperature is low, large particles of AlN will be precipitated, and the effective AlN precipitation in the subsequent process will be reduced. The normalization time is less than 30s, small particles of AlN cannot be completely dissolved, and the effective precipitation amount after decarburization (nitriding) is reduced, resulting in reduced inhibition during high-temperature annealing and reduced magnetic properties of the finished product; in comparative example Q2, the slab hot rolling heating temperature is greater than 1400°C, the heating temperature is high, the grain size of the ingot grows, resulting in the grain size of the hot-rolled plate and the primary recrystallization annealed plate At the same time, if the heating temperature is too high, the burning loss of the ingot will be aggravated, the yield rate will be reduced, and the normalizing time is greater than 180s. If the normalizing time is too long, the favorable precipitation will be aggregated and coarsened, thereby reducing the inhibition force in the subsequent annealing process. At the same time, if the heating time is too long, the grains of the hot-rolled plate will grow, which will lead to the growth of the grain size of the primary recrystallization annealing plate, the instability of the secondary recrystallization, and the reduction of the magnetic properties of the finished product; in the comparative example Q3, the normalizing temperature is less than 1000℃, and the small particles of AlN in the normalizing are difficult to dissolve, and the number of effective precipitations after decarburization (nitriding) is reduced, which leads to the reduction of inhibition force in high-temperature annealing and the reduction of magnetic properties of the finished product.

[0082] In comparative example Q1, the average power is less than 20W, the laser pulse repetition frequency is less than 1kHz, the pulse width is less than 1ms, and the scanning rate is less than 10mm / s, resulting in incomplete removal of the magnesium silicate bottom layer of the final product, and the entire plate surface cannot be smooth. The stamping processability and weldability of the steel plate are poor, the filling line spacing is less than 0.01mm, and the steel strip is locally heated to produce plastic deformation, resulting in poor plate shape; in comparative example Q2, the average power is less than 20W, the laser pulse repetition frequency is less than 1kHz, the pulse width is less than 1ms, and the scanning rate is less than 10mm / s, resulting in the removal of the magnesium silicate bottom layer of the final product. It is incomplete, and the entire plate surface cannot be smooth. The stamping processability and weldability of the steel plate are poor. The filling line spacing is less than 0.01mm. Local heating of the steel strip produces plastic deformation, resulting in poor plate shape. In comparative example Q3, the average power is greater than 3500W, the laser pulse repetition frequency is greater than 160kHz, the pulse width is greater than 10ms, and the scanning rate is greater than 8000mm / s. Local heating of the steel strip produces plastic deformation, resulting in poor plate shape. The filling line spacing is greater than 0.06mm. The magnesium silicate bottom layer of the product is not completely removed, and the entire plate surface cannot be smooth. The stamping processability and weldability of the steel plate are poor.

[0083] Table 3 Performance test results of various embodiments of the present invention and comparative examples

[0084]

[0085]

[0086] It can be seen from Table 3 that the magnetic induction B of the finished product in comparative example Q1 is 800 <1.93T, loss P 17 / 50> 1.25 W / kg, there is a residual magnesium silicate bottom layer on the plate surface, the magnetic properties and plate shape are poor, and the stamping processability and weldability are poor; the finished product magnetic induction B in Comparative Example Q2 800 <1.93 T, loss P 17 / 50 > 1.25 W / kg, there is a residual magnesium silicate bottom layer on the plate surface, the magnetic properties and plate shape are poor, and the stamping processability and weldability are poor; in Comparative Example Q3, since (P + Cu + Sn + Bi + Sb + Cr + As)> 1.80%, the production process cannot proceed and it is a waste product.

[0087] The specific implementation manners are only the best examples and are not restrictive implementations of the technical solutions of the present invention.

Claims

1. A B prepared by laser technology 800 >1.93T ultra-high magnetic induction oriented silicon steel without magnesium silicate bottom layer, characterized by: The composition and weight percentage of the ultra-high magnetic induction oriented silicon are as follows: C: 0.015-0.095%, Si: 2.50- 4.50%, Als: 0.010-0.040%, N: 0.0050-0.0100%, Mn: 0.010-1.00%, S: 0.0030-0.0300%, at least two of P, Cu, Sn, Bi, Sb, Cr and As are added in combination and satisfy the following conditions: (P+Cu+Sn+Bi+Sb+Cr+As)≤1.80%, the rest is iron and unavoidable impurities.

2. A B prepared by laser technology as claimed in claim 1 800 The method for producing ultra-high magnetic induction oriented silicon steel with no magnesium silicate bottom layer of >1.93T is as follows: 1) After smelting, vacuum treatment, and casting into billets; 2) heating the ingot, and controlling the heating temperature at 1100-1400°C; 3) hot rolling, controlling the final rolling temperature at 850-1100° C., and controlling the thickness of the hot rolled plate at 2.0-2.8 mm; 4) Coil the steel sheet and control the coiling temperature not to exceed 600°C; 5) Perform normalization, the normalization temperature is controlled at 1000-1150°C, and keep at this temperature for 30-180s; 6) Perform one cold rolling, and perform at least one aging rolling in the cold rolling, and control the aging temperature at 160-250°C. The thickness of the finished product is 0.15~0.35mm; 7) Carry out decarburization annealing under wet protective atmosphere, control the decarburization annealing temperature at 750-900°C, and keep it at this temperature for 60-180s, with a dew point of 25°C; the protective atmosphere is a mixed gas of wet H2 and N2, wherein the volume content of H2 is 15-80%; 8) Nitriding treatment: When the heating temperature of the ingot is not less than 1260℃, nitriding is not required; When the heating temperature of the ingot is lower than 1260℃, nitriding is required. The nitriding atmosphere is a wet H2, N2 and NH3 mixed gas, in which the H2 volume content is 15-80%, and the amount of nitrogen infiltration is controlled at 50-350PPm. 9) Applying a conventional high temperature annealing separator with MgO as the main component; 10) Perform conventional high temperature annealing; 11) Unwind and laser process under protective atmosphere: Laser processing parameters: The average power of continuous laser is 20~3500W; the laser pulse repetition frequency is 1~ 160kHz; laser pulse width is 1 to 10ms; filling line spacing is 0.01 to 0.06mm; scanning rate is 10~8000mm / s; the focus of the light beam is on the surface of the steel plate; the protective gas is nitrogen or argon, and the protective gas flow rate is 1~50L / min; 12) The steel strip is subjected to conventional stretching and flattening annealing treatment.

3. A B prepared by laser technology as claimed in claim 2 800 >1.93T magnesium silicate-free bottom layer ultra-high magnetic induction oriented silicon steel and method, characterized by: The average power of continuous laser is between 50 and 3350W.

4. A B prepared by laser technology as claimed in claim 2 800 The method of producing ultra-high magnetic induction oriented silicon steel without magnesium silicate bottom layer of >1.93T is characterized by: The laser pulse repetition frequency is between 3 and 150 kHz.

5. The B prepared by laser technology as claimed in claim 2 800 The method of producing ultra-high magnetic induction oriented silicon steel without magnesium silicate bottom layer of >1.93T is characterized by: The spacing between the filling lines is 0.02 to 0.05 mm.

6. A B prepared by laser technology as claimed in claim 2 800 The method of producing ultra-high magnetic induction oriented silicon steel without magnesium silicate bottom layer of >1.93T is characterized by: The scanning rate is between 25 and 7800 mm / s.

7. The B prepared by laser technology as claimed in claim 2 800 The method of producing ultra-high magnetic induction oriented silicon steel without magnesium silicate bottom layer of >1.93T is characterized by: The laser pulse width is between 2 and 8.5 ms.

Images