Self-adhesive oriented silicon steel production method for removing magnesium silicate bottom layer by using laser process

Abstract

The invention discloses a method for producing self-cohesive oriented silicon steel by removing a magnesium silicate bottom layer by using laser. The 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; stretching, flattening and annealing; and coating organic self-adhesive insulating paint and then drying. According to the method, a magnesium silicate bottom layer is completely removed through a laser process, an organic self-adhesive insulating coating containing epoxy resin and a latent curing agent is coated, the magnetic performance B800 is larger than or equal to 1.82 T, P17 / 50 is smaller than or equal to 1.50 W / kg, and the T-type peel strength is larger than or equal to 0.70 N / mm (a finished steel plate is subjected to heat preservation for 1 h at the heat preservation temperature of 200 DEG C and the pressure of 3 MPa); and the performance of the oriented silicon steel punching sheet, namely the one-time punching sheet number of the cutting edge die, can be improved by 8-15 times compared with the existing variety.

Description

Technical Field

[0001] The present invention relates to a cold-rolled grain-oriented silicon steel and a production method thereof, and more particularly to a production method of self-adhesive grain-oriented silicon steel using a laser process to remove the magnesium silicate bottom layer. Background Art

[0002] During the manufacturing process of generators, in order to improve the core iron loss and reduce the product energy consumption, customers plan to develop the use of grain-oriented silicon steel to replace non-oriented silicon steel for manufacturing stator cores, so as to improve the magnetic conductivity of the yoke and teeth. In terms of magnetic properties, it is required that the typical magnetic induction design value can reach more than 1.7T, and in this regard, grain-oriented silicon steel has a complete advantage. In terms of mechanical properties, it is required that the tensile strength in the rolling direction reaches 350 N / mm 2 , and the larger the better. Therefore, the greater the thickness of the grain-oriented silicon steel (the higher the tensile strength), the more suitable it is. Similarly, users have special requirements for the surface of this type of grain-oriented silicon steel for motors. Since the traditional grain-oriented silicon steel forms a magnesium silicate bottom layer on the surface, the surface hardness is high, and it is difficult to stamp and process into shape (such as chipping, wire drawing, high burrs, etc.). Therefore, users hope to develop a grain-oriented silicon steel for motors with a special coating on the surface without a magnesium silicate bottom layer and is easy to stamp and process. At the same time, users hope that some of this type of grain-oriented silicon steel has self-adhesiveness after heating and pressurization to facilitate shaping. This type of grain-oriented silicon steel with a self-adhesive coating on the surface without a magnesium silicate bottom layer has a certain market prospect.

[0003] After retrieval:

[0004] The document with the Chinese patent application number CN201810528553.2 discloses "A Method for Improving the Adhesion of High-Temperature HiB", which includes: subjecting the high-temperature HiB prepared by normalizing and cold-rolling processes to an annealing furnace, introducing a certain amount of ammonia gas into the annealing furnace, performing normal decarburization annealing treatment, and then performing high-temperature annealing and stretch leveling according to the conventional process to obtain high-temperature HiB with improved adhesion. In the existing continuous decarburization annealing furnace for high-temperature HiB of this invention, by introducing an appropriate amount of ammonia gas to corrode the surface of the steel plate, the corrosion degree of the iron matrix on the surface of the steel plate can be increased. When the nitriding amount is controlled at 10-20 ppm, the effect of bottom layer nailing of the finished product is obvious, and the adhesion is greatly improved. The proportion above grade C reaches 100%, and the proportion above grade B reaches 80%. However, the surface of this invention is in the mode of traditional grain-oriented silicon steel magnesium silicate bottom layer + T2 tension coating, which is not conducive to stamping and processing and has no self-bonding property.

[0005] The literature with the Chinese patent application number CN201911126518.9 discloses "An oriented silicon steel with self - bonding property and its preparation method". The main chemical composition by weight percentage is C 0.020 - 0.095%, Si 2.80 - 3.60%, Als 0.020 - 0.035%, N 0.0050 - 0.0100%, Mn 0.010 - 1.00%, S 0.0030 - 0.03%, and the rest is iron and inevitable impurities. Through low - temperature or high - temperature hot rolling at 1100°C - 1400°C and normalizing treatment of the hot - rolled plate at 1000°C - 1150°C, after one - time cold rolling, decarburization annealing, nitriding treatment (no nitriding when the hot - rolled slab is heated at ≥1260°C), coating with magnesium oxide isolation coating and high - temperature annealing, an oriented silicon steel without a magnesium silicate bottom layer with a thickness of 0.15 mm - 0.50 mm is obtained. After coating with an organic self - adhesive insulating coating containing a mixture of epoxy resin and latent curing agent, B 800 ≥1.80 T, P 17 / 50 ≤1.60 W / kg finished product performance, T - type peel strength ≥0.50 N / mm, and an oriented silicon steel finished product with self - adhesiveness is obtained. By improving processes such as high - temperature annealing release agent, etc., the invention can obtain an oriented silicon steel without forming a magnesium silicate bottom layer. However, during the high - temperature annealing process, the inhibitor is unstable, and secondary recrystallization cannot be stably completed, resulting in unstable magnetic properties. Moreover, it is difficult to obtain an oriented silicon steel without a bottom layer with a smooth full surface, which affects the peel strength of the finished product after coating and leads to a decrease in self - adhesiveness.

[0006] It can be seen that the above - mentioned patent either has a traditional magnesium silicate bottom layer + T2 tension coating for oriented silicon steel, which is not conducive to punching processing and has no self - adhesiveness, or the inhibitor is unstable during the high - temperature annealing process, resulting in unstable magnetic properties, and it is difficult to obtain an oriented silicon steel without a magnesium silicate bottom layer with a smooth full surface, which is not conducive to punching processing and has no self - adhesiveness. All of these have essential differences from the present invention. Summary of the Invention

[0007] The present invention aims to overcome the deficiencies of the existing technology and provides an oriented silicon steel with self - bonding property using a laser process to remove the magnesium silicate bottom layer, with magnetic properties B 800 ≥1.82 T, P 17 / 50 ≤1.50 W / kg, T - type peel strength ≥0.70 N / mm (the finished steel plate is kept at a temperature of 200°C and a pressure of 3 MPa for 1 h), and the punching performance of the oriented silicon steel, that is, the number of punches per die of the cutting die, can be increased by 8 - 15 times compared with existing varieties.

[0008] Measures to achieve the above object:

[0009] A production method of an oriented silicon steel with self - bonding property using a laser to remove the magnesium silicate bottom layer, the steps are as follows:

[0010] 1) Smelted, vacuum-treated, and cast into billets;

[0011] 2) Heat the billets, with the heating temperature controlled at 1100 - 1400 °C;

[0012] 3) Conduct hot rolling, control the finishing rolling temperature at 850 - 1100 °C, and the thickness of the hot-rolled sheet at 2.0 - 2.8 mm;

[0013] 4) Coil, with the coiling temperature controlled not to exceed 600 °C;

[0014] 5) Normalize, with the normalizing temperature controlled at 1000 - 1150 °C, and hold at this temperature for 30 -

[0015] 180 s;

[0016] 6) Conduct primary cold rolling, with 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;

[0017] 7) Conduct 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 the dew point at 25 °C; the protective atmosphere is a mixed gas of wet H2 and N2, where the volume content of H2 is 15 - 80%;

[0018] 8) Conduct nitriding treatment:

[0019] When the heating temperature of the billets is not lower than 1260 °C, nitriding is not required;

[0020] When the heating temperature of the billets 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 nitrogen infiltrated at 50 - 350 ppm;

[0021] 9) Coat with a conventional high-temperature annealing release agent mainly composed of MgO;

[0022] 10) Conduct conventional high-temperature annealing;

[0023] 11) Uncoil and conduct laser treatment under a protective atmosphere:

[0024] Laser treatment parameters: The average power of continuous laser is 20 - 3500 W; the repetition

[0025] frequency of laser pulses is 1 - 160 kHz; the width of laser pulses is 1 - 10 ms; the filling line spacing is

[0026] 0.01 to 0.06 mm; the scanning speed is 10 to 8000 mm / s; the focus of the beam is focused on the surface of the steel plate; the shielding gas is nitrogen or argon, and the shielding gas flow rate is 1 to 50 L / min;

[0027] 12) Carry out conventional stretcher leveling annealing treatment on the steel strip;

[0028] 13) After coating with an organic self-adhesive insulating paint containing a mixture of epoxy resin and latent curing agent, dry it;

[0029] Control the single-sided coating thickness to be 1 to 10 μm.

[0030] Preferably: the average power of the continuous laser is 45 to 3420 W.

[0031] Preferably: the laser pulse repetition frequency is 8 to 145 kHz.

[0032] Preferably: the filling wire pitch is 0.02 to 0.05 mm.

[0033] Preferably: the scanning speed is 20 to 7750 mm / s.

[0034] Preferably: the laser pulse width is 1.5 to 9.5 ms.

[0035] It lies in that: the components and weight percentage contents of the self-bonding oriented silicon steel are: C: 0.015 to 0.095%, Si: 2.50 to 4.50%, Als: 0.010 to 0.040%, N: 0.0050 to 0.0100%, Mn: 0.010 to 1.00%, S: 0.0030 to 0.0300%, any at least two of P, Cu, Sn, Bi, Sb, Cr and As and satisfying (P + Cu + Sn + Bi + Sb + Cr + As) ≤ 1.80%, and the rest are iron and unavoidable impurities.

[0036] It lies in that: the composition and weight percentage content of the organic self-adhesive insulating paint are: epoxy resin: 25 to 70%, latent curing agent: 2.0 to 5.0%, and the rest is water.

[0037] The mechanism and function of each element and the main process in the present invention

[0038] The reason why the heating temperature of the steel billet in the present invention is controlled at 1100 to 1400 °C is that it is necessary to ensure that part of the AlN in the continuous casting billet is solid-solved or completely and fully solid-solved, and AlN second-phase particles with appropriate sizes are formed in the subsequent processes.

[0039] The reason why the finish rolling temperature of the present invention is limited within the range of 850 - 1100 °C to ensure hot rolling within a relatively high temperature range is that it is necessary to ensure hot rolling within a relatively high temperature range and a relatively high finish rolling temperature, so that no large - particle second - phase particles such as AlN precipitate during the hot rolling process.

[0040] The reason why the normalizing temperature of the present invention is controlled at 1000 - 1150 °C and held at this temperature for 30 - 180 s is that in order 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 a temperature below 1000 °C, due to the low temperature, it is difficult for AlN 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.

[0041] The reason why at least one pass of aging rolling at 160 - 250 °C is controlled during cold rolling in the present invention is that cold - rolling aging can increase the content of carbon and nitrogen dissolved in the steel. During cold rolling, the dissolved carbon and nitrogen accumulate at dislocations, hinder the movement of dislocations, 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.

[0042] The reason why the decarburizing annealing temperature is controlled at 750 - 900 °C and held at this temperature for 60 - 180 s, the furnace dew - point is at 15 - 55 °C, and the protective atmosphere is a wet H2 and N2 mixed gas with the H2 volume content of 15 - 80% is as follows: to complete primary recrystallization, so that there are a sufficient number of

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

[0043] The reason why nitriding treatment must be carried out in the subsequent process when the casting blank heating temperature is 1100 - 1260 °C, and nitriding treatment is not required in the subsequent process when the heating temperature is 1260 - 1400 °C is that when the casting blank heating temperature is 1100 - 1260 °C, only part of the AlN in the casting blank can be solid - solved, and nitriding treatment must be carried out in the annealing process to increase the content of AlN second - phase particles to ensure sufficient inhibitory force to obtain a perfect secondary recrystallization structure and texture; when the heating temperature is 1260 - 1400 °C, the AlN in the casting blank can be completely and fully solid - solved, and a sufficient amount of AlN second - phase particles can be obtained in the normalizing and annealing processes of the hot - rolled sheet to ensure sufficient inhibitory force to obtain a perfect secondary recrystallization structure and texture, so nitriding treatment is not required.

[0044] The purpose of nitriding treatment is as follows: ensuring that there is sufficient nitrogen content in the steel to form AlN and (Si,Al)N, forming favorable secondary phases, inhibiting the normal growth of primary grains during high-temperature annealing, and promoting the perfection of secondary recrystallization.

[0045] Coating a high-temperature annealing isolation agent with MgO as the main component serves to isolate the layers of the steel coil during high-temperature annealing.

[0046] The reason for controlling the laser treatment parameters in the present invention is as follows: 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 rate is 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 flow rate of the protective gas is 1 - 50 L / min. Based on the difference in the damage thresholds between the magnesium silicate bottom layer and the substrate, the removal of the magnesium silicate bottom layer with low damage and smooth surface across the whole plate of grain-oriented silicon steel is achieved through processes such as precise ablation of the magnesium silicate bottom layer by high-energy pulsed laser, rapid scanning by a galvanometer scanner, purging with protective gas, and filtering by a fume extractor. Its feature is that the position of the galvanometer scanner can be adjusted longitudinally to make the focus of the light beam focus on the surface of the steel plate, achieving complete and efficient removal of the magnesium silicate bottom layer, being easy to automate control, and having the effect of a smooth surface across the whole plate. By subjecting the steel strip to temper rolling and annealing treatment, grain-oriented silicon steel without a magnesium silicate bottom layer with a smooth surface across the whole plate and high magnetic induction is obtained.

[0047] However, when the average power of the laser is lower than 20W, incomplete removal of the underlying magnesium silicate layer of the final product will occur, and full-surface smoothness cannot be achieved (poor steel plate stamping processability, poor self-adhesion of the finished product after coating); 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 underlying magnesium silicate layer of the final product will occur, and full-surface smoothness cannot be achieved (poor steel plate stamping processability, poor self-adhesion of the finished product after coating); 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 underlying magnesium silicate layer of the final product will occur, and full-surface smoothness cannot be achieved (poor steel plate stamping processability, poor self-adhesion of the finished product after coating); 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 underlying magnesium silicate layer of the final product will occur, and full-surface smoothness cannot be achieved (poor steel plate stamping processability, poor self-adhesion of the finished product after coating); when the laser scanning rate is lower than 10mm / s, incomplete removal of the underlying magnesium silicate layer of the final product will occur, and full-surface smoothness cannot be achieved (poor steel plate stamping processability, poor self-adhesion of the finished product after coating); 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.

[0048] The reason why the organic self-adhesive insulating coating containing a mixture of epoxy resin and latent curing agent is coated after stretcher leveling annealing in the present invention is that it is necessary to increase the insulation performance of the surface of the finished steel plate, while reducing the surface hardness of the steel plate, which is beneficial to the stamping processing and forming of the steel plate. At the same time, through the reasonable ratio of epoxy resin and latent curing agent, the self-adhesion of the steel plate after stamping and heating and pressing can be increased, which is beneficial to self-adhesive forming.

[0049] Compared with the prior art, the present invention uses a laser process to completely remove the underlying magnesium silicate layer and coats an organic self-adhesive insulating coating containing a mixture of epoxy resin and latent curing agent. The magnetic property B 800 ≥1.82T, P 17 / 50 ≤1.50W / kg, the T-peel strength ≥0.70N / mm (the finished steel plate is kept at a temperature of 200°C and a pressure of 3MPa for 1h), and it can increase the punching performance of the grain-oriented silicon steel sheet, that is, the number of punched sheets in one die cutting is 8 - 15 times higher than that of the existing varieties. Detailed implementation mode

[0050] The present invention will be described in detail below:

[0051] Table 1 is a list of component values for each embodiment and comparative example of the present invention;

[0052] Table 2 is a list of main process parameters for each embodiment and comparative example of the present invention;

[0053] Table 3 is a list of the compositions of the high-temperature annealing isolation agent and the organic insulating coating in each embodiment and comparative example of the present invention;

[0054] Table 4 is a list of the performance test results for each embodiment and comparative example of the present invention.

[0055] Each embodiment of the present invention is produced according to the following steps:

[0056] 1) Smelting, vacuum treatment, and casting into billets;

[0057] 2) Heating the billets, with the heating temperature controlled at 1100 - 1400 °C;

[0058] 3) Performing hot rolling, controlling the final rolling temperature at 850 - 1100 °C, and the thickness of the hot-rolled sheet at 2.0 - 2.8 mm;

[0059] 4) Coiling, controlling the coiling temperature not exceeding 600 °C;

[0060] 5) Normalizing, controlling the normalizing temperature at 1000 - 1150 °C, and holding at this temperature for 30 -

[0061] 180 s;

[0062] 6) Performing primary cold rolling, with at least one pass of age rolling during cold rolling, controlling the age temperature at 160 - 250 °C, and the finished product thickness at 0.15 - 0.35 mm;

[0063] 7) Decarburization annealing is carried out under a wet protective atmosphere, controlling the decarburization annealing temperature at 750 - 900 °C, and holding 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%;

[0064] 8) Nitriding treatment:

[0065] When the heating temperature of the billet is not lower than 1260 °C, nitriding is not required;

[0066] When the heating temperature of the billet is lower than 1260 °C, nitriding is required; the nitriding atmosphere is a mixed gas of wet H2, N2

[0067] and NH3, where the volume content of H2 is 15 - 80%; and controlling the amount of nitrogen infiltrated at

[0068] 50 - 350 ppm;

[0069] 9) Coating with a conventional high-temperature annealing isolation agent mainly composed of MgO;

[0070] 10) Conducting conventional high-temperature annealing;

[0071] 11) Uncoiling and laser processing under a protective atmosphere:

[0072] Laser processing parameters: 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

[0073] 0.01 - 0.06 mm; the scanning rate 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;

[0074] 12) Conducting conventional stretch leveling annealing treatment on the steel strip;

[0075] 13) Coating with an organic self-adhesive insulating coating containing a mixture of epoxy resin and latent curing agent and then drying;

[0076] Controlling the single-sided coating thickness to be 1 - 10 μm.

[0077] Table 1 List of chemical component values of each example and comparative example of the present invention (wt%)

[0078]

[0079] As can be seen from Table 1, in comparative example Q1, Als < 0.010%, the Als content is low, the number of AlN precipitates after decarburization (nitriding) decreases, 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 high, and it is difficult to completely dissolve during heating at 1100°C - 1400°C, resulting in a decrease in the effective precipitation quantity after decarburization (nitriding), thereby leading to 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 interface enrichment elements is too high, the hot-rolled edge cracking is extremely large, and production is difficult to carry out smoothly.

[0080] Table 2 List of main process parameters of each example and comparative example of the present invention

[0081]

[0082] Continued Table 2

[0083]

[0084]

[0085] Note: Except for the listed materials, the rest of the organic insulating coatings in Table 2 are water;

[0086] The shielding gas is nitrogen or argon, which are interchangeable.

[0087] From Table 2 we can see that:

[0088] 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 ingot grain size grows, resulting in the hot-rolled plate and the primary recrystallization annealed plate grain size 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 the magnetic properties of the finished product.

[0089] 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 of the steel plate is poor, the self-adhesion of the finished plate surface after coating is 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 incomplete removal of the magnesium silicate bottom layer of the final product, The entire board surface cannot be smooth, the steel plate has poor stamping processability, the self-adhesion of the finished board surface after coating is poor, the filling line spacing is less than 0.01mm, and the steel belt locally heats up and produces plastic deformation, resulting in a poor board 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, the scanning rate is greater than 8000mm / s, the steel belt locally heats up and produces plastic deformation, resulting in a poor board shape, the filling line spacing is greater than 0.06mm, the magnesium silicate bottom layer of the product is not completely removed, the entire board surface cannot be smooth, the steel plate has poor stamping processability, and the self-adhesion of the finished board surface after coating is poor.

[0090] Table 3 Performance test results of various embodiments of the present invention and comparative examples

[0091]

[0092]

[0093] As can be seen from Table 3, for Comparative Example Q1, the finished product magnetic induction B 800 < 1.82 T, and the loss P 17 / 50 > 1.50 W / kg. There is a residual magnesium silicate bottom layer on the plate surface, the content of epoxy resin in the insulating paint is low, the T-peel strength is low, the plate shape is poor, and the stamping processability and self-adhesion are poor; for Comparative Example Q2, the finished product magnetic induction B 800 < 1.82 T, and the loss P 17 / 50 > 1.50 W / kg. There is a residual magnesium silicate bottom layer on the plate surface, the content of epoxy resin in the insulating paint is low, the T-peel strength is low, the plate shape is poor, and the stamping processability and self-adhesion are poor; for Comparative Example Q3, since (P + Cu + Sn + Bi +

[0094] Sb + Cr + As)> 1.80%, the production process cannot proceed, and it is a waste product.

[0095] This specific implementation manner is only the best example and is not a restrictive implementation of the technical solution of the present invention.

Claims

1. A method for producing self-adhesive oriented silicon steel by removing the magnesium silicate bottom layer using a laser process, the steps of which are 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 the hot rolled plate thickness 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) performing a cold rolling, performing at least one aging rolling during the cold rolling, controlling the aging temperature at 160-250° C., and the finished product thickness at 0.15-0.35 mm; 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, wherein the H2 volume content is 15-80%; and the amount of nitrogen infiltrated 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) Performing conventional stretching and flattening annealing treatment on the steel strip; 13) Apply an organic self-adhesive insulating coating containing a mixture of epoxy resin and latent curing agent and then dry; control the single-sided coating thickness to be 1 to 10 μm.

2. The method for producing self-adhesive oriented silicon steel by removing the magnesium silicate bottom layer by laser process as claimed in claim 1, characterized in that: The average power of continuous laser is between 45 and 3420W.

3. The method for producing self-adhesive grain-oriented silicon steel by removing the magnesium silicate bottom layer using a laser process as claimed in claim 1, characterized in that: The laser pulse repetition frequency is between 8 and 145 kHz.

4. The method for producing self-adhesive grain-oriented silicon steel by removing the magnesium silicate bottom layer by laser process as claimed in claim 1, characterized in that: The spacing between the filling lines is 0.02 to 0.05 mm.

5. The method for producing self-adhesive grain-oriented silicon steel by removing the magnesium silicate bottom layer using a laser process as claimed in claim 1, characterized in that: The scanning rate is between 20 and 7750 mm / s.

6. The method for producing self-adhesive grain-oriented silicon steel by removing the magnesium silicate bottom layer using a laser process as claimed in claim 1, characterized in that: The laser pulse width is between 1.5 and 9.5 ms.

7. The method for producing self-adhesive grain-oriented silicon steel by removing the magnesium silicate bottom layer by laser process as claimed in claim 1, characterized in that: The components and weight percentage contents of the self-adhesive oriented silicon steel 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 any one of P, Cu, Sn, Bi, Sb, Cr and As and satisfying (P+Cu+Sn+Bi+Sb+Cr+As)≤1.80%, and the rest are iron and unavoidable impurities.

8. The method for producing self-adhesive grain-oriented silicon steel by removing the magnesium silicate bottom layer using a laser process as claimed in claim 1, characterized in that: The composition and weight percentage of the organic self-adhesive insulating coating are as follows: epoxy resin: 25~ 70%, latent curing agent: 2.0-5.0%, and the rest is water.

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