Cold-rolled silicon steel thin strip and method of processing the same

Abstract

The application discloses a kind of cold-rolled silicon steel thin strips and processing method thereof, it is related to silicon steel strip technical field.The silicon steel plate is cold-rolled into ultra-thin silicon steel strip, then using activation liquid is activated and is handled after coating anticorrosive coating, so that the prepared ultra-thin silicon steel strip has good corrosion resistance.The application adds phytic acid and modified polyaspartic acid in activation liquid.Polysuccinimide is used as raw material, and dopamine is added for graft modification, to obtain a polymer with polyaspartic acid as skeleton, grafted dopamine, dopamine has catechol group, further enhances the chelating property of polyaspartic acid to metal ions on iron-based organic skeleton material.Adding phytic acid in activation liquid, phytic acid can form nano-porous structure with modified polyaspartic acid, conducive to subsequent modified silica sol loading, to further enhance the corrosion resistance of ultra-thin silicon steel strip.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon steel strips, in particular to a cold-rolled silicon steel strip and a processing method thereof. Background Art

[0002] Cold-rolled silicon steel strip is an important electrical material, widely used in motors, transformers, and other electrical equipment. By adding silicon, silicon steel increases the resistivity of the iron-based alloy and reduces eddy current losses, resulting in excellent magnetic permeability in high-frequency electromagnetic environments. Due to its excellent magnetic and electrical conductivity, cold-rolled silicon steel strip plays an indispensable role in modern electrical engineering. Silicon steel strip also has excellent workability. Cold-rolled silicon steel strip has excellent ductility and processing properties, making it suitable for the manufacture of electromagnetic components of various complex shapes. However, over long-term use, silicon steel strip is susceptible to corrosion from corrosive media, resulting in a reduced service life.

[0003] In order to solve the above problems and improve the corrosion resistance of silicon steel strips, the present invention provides a cold-rolled silicon steel strip and a processing method thereof. Summary of the Invention

[0004] The object of the present invention is to provide a cold-rolled silicon steel strip and a processing method thereof, so as to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for processing a cold-rolled silicon steel strip comprises the following steps:

[0007] Step 1: cold rolling the silicon steel sheet to obtain a silicon steel strip;

[0008] Step 2: Take a silicon steel strip, clean and dry it to obtain a pretreated silicon steel strip; then place the pretreated silicon steel strip in an activation solution for activation treatment, heat it to 105-110° C. and keep it warm for 12-14 hours to obtain an activated silicon steel strip;

[0009] Step 3: using an immersion Czochralski method to prepare an anti-corrosion coating on the surface of the activated silicon steel strip using modified silica sol, and then performing a magnetic thermal coupling treatment and cooling to obtain a cold-rolled silicon steel strip;

[0010] The preparation of the activation solution includes the following steps: mixing isopropyl alcohol and glycerol for 5-10 minutes, adding a mixture of ferric nitrate nonahydrate, zinc nitrate hexahydrate, phytic acid, modified polyaspartic acid, urea, sodium carbonate, and deionized water, and ultrasonically stirring for 10-15 minutes to obtain the activation solution.

[0011] More optimally, the preparation method of the modified polyaspartic acid is as follows: take dimethyl sulfoxide and triethylamine, add dopamine hydrochloride, stir evenly to obtain a mixed solution; take polysuccinimide and dimethyl sulfoxide, stir evenly, add the mixed solution, pass nitrogen, heat to 80-85°C, stir for 22-26 hours, add sodium hydroxide and deionized water, react at 60-65°C for 22-26 hours, add hydrochloric acid, adjust the pH value to 6.0-6.2, dialyze, and freeze-dry to obtain modified polyaspartic acid.

[0012] More optimally, the preparation method of the modified silica sol is: mix and stir ethyl orthosilicate, dodecyltriethoxysilane, and anhydrous ethanol, add deionized water and an iron-based organic framework material loaded with a corrosion inhibitor, ultrasonically stir for 5-10 minutes, heat to 60-65°C and keep warm for 1-3 hours to obtain the modified silica sol.

[0013] More optimally, the method for preparing the corrosion inhibitor-loaded iron-based organic framework material comprises the following steps:

[0014] S1: Take trimesic acid, ferric nitrate nonahydrate, and deionized water, stir evenly, add dilute nitric acid, heat to 115-120°C, react for 10-12 hours, cool, filter, wash, and dry to obtain an iron-based organic framework material;

[0015] S2: Take an iron-based organic framework material and ethanol, stir them evenly, add benzotriazole, stir for 12-14 hours, filter, and dry to obtain an iron-based organic framework material loaded with a corrosion inhibitor.

[0016] More optimally, the silicon steel plate is composed of the following components, calculated by mass fraction: 2.5wt%-3.5wt% silicon, 0.06wt%-0.10wt% manganese, 0.05wt%-0.06wt% aluminum, 0.25wt%-0.034wt% tin, 0.018wt%-0.022wt% phosphorus, 0.002wt%-0.003wt% carbon, and the balance is iron.

[0017] More optimally, the working conditions of the immersion pulling method are: during pulling, the surface of the activated silicon steel strip is immersed in the modified silica sol for 40-60 seconds, the activated silicon steel strip is pulled out at a rate of 4500 μm / s, and then dried.

[0018] More optimally, the silicon steel plate is composed of the following components, calculated by mass fraction: 3.0wt%-3.3wt% silicon, 0.08wt%-0.10wt% manganese, 0.05wt%-0.06wt% aluminum, 0.3wt%-0.032wt% tin, 0.018wt%-0.020wt% phosphorus, 0.002wt%-0.003wt% carbon, and the balance is iron.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention cold-rolls a silicon steel sheet into an ultra-thin silicon steel strip, and then uses an activation liquid to activate it and then coats it with an anti-corrosion coating, so that the prepared ultra-thin silicon steel strip has good corrosion resistance.

[0021] (2) The present invention adds phytic acid and modified polyaspartic acid to the activation solution. Using polysuccinimide as a raw material and adding dopamine for grafting modification, a polymer with polyaspartic acid as a backbone and grafted dopamine is obtained. The dopamine has a catechol group, which further enhances the polyaspartic acid's chelating ability for metal ions on the iron-based organic framework material. Phytic acid is also added to the activation solution. Phytic acid can form a nanoporous structure with the modified polyaspartic acid, which facilitates the subsequent loading of modified silica sol, thereby further enhancing the corrosion resistance of the ultra-thin silicon steel strip.

[0022] (3) The present invention uses trimesic acid and ferric nitrate nonahydrate to prepare an iron-based organic framework material. The iron-based organic framework material has high porosity and large specific surface area, and is loaded with benzotriazole, which enhances the corrosion resistance of the modified silica sol. The metal ions in the iron-based organic framework material can form a chelate reaction with the modified polyaspartic acid, thereby increasing the loading rate of the iron-based organic framework material and enhancing the corrosion resistance of the ultra-thin silicon steel strip. DETAILED DESCRIPTION

[0023] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0024] There is no particular limitation on the sources and purchase channels of the raw materials involved in the present invention, and examples thereof include: polysuccinimide: which can be purchased from Maclean, model: P871967; amino-terminated polyethylene glycol: which can be purchased from Maclean, model: N902461.

[0025] Example 1: A method for processing a cold-rolled silicon steel strip, comprising the following steps:

[0026] Step 1: cold rolling the silicon steel sheet to 0.02 mm using a four-roll mill, with a cold rolling reduction of 68% to obtain a silicon steel strip;

[0027] The silicon steel sheet is composed of the following components, calculated by mass fraction: 3 wt% silicon, 0.07 wt% manganese, 0.055 wt% aluminum, 0.30 wt% tin, 0.020 wt% phosphorus, 0.0025 wt% carbon, and the balance is iron;

[0028] Step 2: taking a silicon steel strip, cleaning and drying it to obtain a pretreated silicon steel strip; then placing the pretreated silicon steel strip in an activation solution for activation treatment, heating it to 108° C. and maintaining it for 13 hours to obtain an activated silicon steel strip;

[0029] The activation solution was prepared by mixing 210 mL of isopropyl alcohol and 30 mL of glycerol for 8 minutes, adding a mixture of 0.4 g of ferric nitrate nonahydrate, 0.35 g of zinc nitrate hexahydrate, 0.15 g of phytic acid, 0.3 g of modified polyaspartic acid, 0.1 g of urea, 0.15 g of sodium carbonate, and 10 mL of deionized water, and ultrasonically stirring for 12 minutes to obtain the activation solution;

[0030] The preparation method of the modified polyaspartic acid is:

[0031] 2 mL of dimethyl sulfoxide and 0.4 mL of triethylamine were added to 0.6 g of dopamine hydrochloride and stirred to obtain a mixed solution; 1 g of polysuccinimide and 20 mL of dimethyl sulfoxide were added to the mixed solution, nitrogen was passed through, the temperature was raised to 82°C, and the mixture was stirred for 24 h. 0.4 g of sodium hydroxide and 5 mL of deionized water were added and the mixture was reacted at 62°C for 24 h. 0.1 mol / L hydrochloric acid was added to adjust the pH to 6.0, the mixture was dialyzed, and lyophilized to obtain modified polyaspartic acid;

[0032] Step 3: using an immersion Czochralski method to prepare an anti-corrosion coating on the surface of the activated silicon steel strip using modified silica sol, and then performing a magnetic thermal coupling treatment and cooling to obtain a cold-rolled silicon steel strip;

[0033] The working conditions of the immersion pulling method are as follows: during pulling, the surface of the activated silicon steel strip is immersed in the modified silica sol for 50 seconds, the activated silicon steel strip is pulled out at a rate of 4500µm / s, and dried;

[0034] The preparation method of modified silica sol is:

[0035] S1: Take 1.4 g of trimesic acid, 4.4 g of ferric nitrate nonahydrate, and 40 mL of deionized water, stir evenly, add 1.4 mL of dilute nitric acid, heat to 117°C, react for 11 h, cool, filter, wash, and dry to obtain an iron-based organic framework material;

[0036] S2: Take 1 g of iron-based organic framework material and 200 mL of ethanol, stir evenly, add 2.2 g of benzotriazole, stir for 13 h, filter and dry to obtain the iron-based organic framework material loaded with corrosion inhibitor;

[0037] S3: 15 g of ethyl orthosilicate, 5 g of dodecyltriethoxysilane, and 46 g of anhydrous ethanol were mixed and stirred, 10 mL of deionized water and 1 g of an iron-based organic framework material loaded with a corrosion inhibitor were added, and ultrasonic stirring was performed for 8 min. The temperature was raised to 62°C and kept for 2 h to obtain a modified silica sol;

[0038] The working conditions of the magnetothermal coupling treatment are as follows: a silicon steel strip with an insulating coating is placed vertically in a quartz tube so that the silicon steel strip is perpendicular to the direction of the magnetic field. The loaded current is a unilateral rectangular pulse current with a peak current of 185A, a time of 160s, a temperature of 380°C, a frequency of 40Hz, and a duty cycle of 60%.

[0039] Example 2: A method for processing a cold-rolled silicon steel strip, comprising the following steps:

[0040] Step 1: cold rolling the silicon steel sheet to 0.02 mm using a four-roll mill, with a cold rolling reduction of 68% to obtain a silicon steel strip;

[0041] The silicon steel sheet is composed of the following components, calculated by mass fraction: 2.5wt% silicon, 0.06wt% manganese, 0.05wt% aluminum, 0.25wt% tin, 0.018wt% phosphorus, 0.002wt% carbon, and the balance is iron;

[0042] Step 2: taking a silicon steel strip, cleaning and drying it to obtain a pretreated silicon steel strip; then placing the pretreated silicon steel strip in an activation solution for activation treatment, heating it to 105° C. and maintaining it for 12 hours to obtain an activated silicon steel strip;

[0043] The activation solution was prepared by mixing 210 mL of isopropyl alcohol and 30 mL of glycerol for 5 minutes, adding a mixture of 0.4 g of ferric nitrate nonahydrate, 0.35 g of zinc nitrate hexahydrate, 0.15 g of phytic acid, 0.3 g of modified polyaspartic acid, 0.1 g of urea, 0.15 g of sodium carbonate, and 10 mL of deionized water, and ultrasonically stirring for 10 minutes to obtain the activation solution.

[0044] The preparation method of the modified polyaspartic acid is:

[0045] 2 mL of dimethyl sulfoxide and 0.4 mL of triethylamine were added to 0.6 g of dopamine hydrochloride and stirred to obtain a mixed solution; 1 g of polysuccinimide and 20 mL of dimethyl sulfoxide were added to the mixed solution, nitrogen was passed through, the temperature was raised to 80°C, and the mixture was stirred for 22 h. 0.4 g of sodium hydroxide and 5 mL of deionized water were added and the mixture was reacted at 60°C for 22 h. 0.1 mol / L hydrochloric acid was added to adjust the pH to 6.0, the mixture was dialyzed, and lyophilized to obtain modified polyaspartic acid;

[0046] Step 3: using an immersion Czochralski method to prepare an anti-corrosion coating on the surface of the activated silicon steel strip using modified silica sol, and then performing a magnetic thermal coupling treatment and cooling to obtain a cold-rolled silicon steel strip;

[0047] The working conditions of the immersion pulling method are as follows: during pulling, the surface of the activated silicon steel strip is immersed in the modified silica sol for 40 seconds, the activated silicon steel strip is pulled out at a rate of 4500µm / s, and dried;

[0048] The preparation method of modified silica sol is:

[0049] S1: Take 1.4 g of trimesic acid, 4.4 g of ferric nitrate nonahydrate, and 40 mL of deionized water, stir evenly, add 1.4 mL of dilute nitric acid, heat to 115°C, react for 10 h, cool, filter, wash, and dry to obtain an iron-based organic framework material;

[0050] S2: Take 1g of iron-based organic framework material and 200mL of ethanol, stir evenly, add 2.2g of benzotriazole, stir for 12h, filter and dry to obtain the iron-based organic framework material loaded with corrosion inhibitor;

[0051] S3: 15 g of ethyl orthosilicate, 5 g of dodecyltriethoxysilane, and 46 g of anhydrous ethanol were mixed and stirred, 10 mL of deionized water and 1 g of an iron-based organic framework material loaded with a corrosion inhibitor were added, ultrasonically stirred for 5 min, and heated to 60°C and kept warm for 1 h to obtain a modified silica sol;

[0052] The working conditions of the magnetothermal coupling treatment are as follows: a silicon steel strip with an insulating coating is placed vertically in a quartz tube so that the silicon steel strip is perpendicular to the direction of the magnetic field. The loaded current is a unilateral rectangular pulse current with a peak current of 185A, a time of 160s, a temperature of 380°C, a frequency of 40Hz, and a duty cycle of 60%.

[0053] Example 3: A method for processing a cold-rolled silicon steel strip, comprising the following steps:

[0054] Step 1: cold rolling the silicon steel sheet to 0.02 mm using a four-roll mill, with a cold rolling reduction of 68% to obtain a silicon steel strip;

[0055] The silicon steel sheet is composed of the following components, calculated by mass fraction: 3.5 wt% silicon, 0.10 wt% manganese, 0.06 wt% aluminum, 0.034 wt% tin, 0.022 wt% phosphorus, 0.003 wt% carbon, and the balance iron;

[0056] Step 2: taking a silicon steel strip, cleaning and drying it to obtain a pretreated silicon steel strip; then placing the pretreated silicon steel strip in an activation solution for activation treatment, heating it to 110° C. and maintaining it for 14 hours to obtain an activated silicon steel strip;

[0057] The activation solution was prepared by mixing 210 mL of isopropyl alcohol and 30 mL of glycerol and stirring for 10 minutes, adding a mixture of 0.4 g of ferric nitrate nonahydrate, 0.35 g of zinc nitrate hexahydrate, 0.15 g of phytic acid, 0.3 g of modified polyaspartic acid, 0.1 g of urea, 0.15 g of sodium carbonate, and 10 mL of deionized water, and stirring with ultrasonic waves for 15 minutes to obtain the activation solution;

[0058] The preparation method of the modified polyaspartic acid is:

[0059] 2 mL of dimethyl sulfoxide and 0.4 mL of triethylamine were added to 0.6 g of dopamine hydrochloride and stirred to obtain a mixed solution; 1 g of polysuccinimide and 20 mL of dimethyl sulfoxide were added to the mixed solution, nitrogen was passed through, the temperature was raised to 85°C, and the mixture was stirred for 26 h. 0.4 g of sodium hydroxide and 5 mL of deionized water were added and the mixture was reacted at 65°C for 26 h. 0.1 mol / L hydrochloric acid was added to adjust the pH to 6.2, the mixture was dialyzed, and lyophilized to obtain modified polyaspartic acid;

[0060] Step 3: using an immersion Czochralski method to prepare an anti-corrosion coating on the surface of the activated silicon steel strip using modified silica sol, and then performing a magnetic thermal coupling treatment and cooling to obtain a cold-rolled silicon steel strip;

[0061] The working conditions of the immersion pulling method are as follows: during pulling, the surface of the activated silicon steel strip is immersed in the modified silica sol for 40 seconds, the activated silicon steel strip is pulled out at a rate of 4500µm / s, and dried;

[0062] The preparation method of modified silica sol is:

[0063] S1: Take 1.4 g of trimesic acid, 4.4 g of ferric nitrate nonahydrate, and 40 mL of deionized water, stir evenly, add 1.4 mL of dilute nitric acid, heat to 120°C, react for 12 h, cool, filter, wash, and dry to obtain an iron-based organic framework material;

[0064] S2: Take 1 g of iron-based organic framework material and 200 mL of ethanol, stir evenly, add 2.2 g of benzotriazole, stir for 14 h, filter and dry to obtain the iron-based organic framework material loaded with corrosion inhibitor;

[0065] S3: 15 g of ethyl orthosilicate, 5 g of dodecyltriethoxysilane, and 46 g of anhydrous ethanol were mixed and stirred, 10 mL of deionized water and 1 g of an iron-based organic framework material loaded with a corrosion inhibitor were added, ultrasonically stirred for 10 min, and heated to 65°C and kept warm for 3 h to obtain a modified silica sol;

[0066] The working conditions of the magnetothermal coupling treatment are as follows: a silicon steel strip with an insulating coating is placed vertically in a quartz tube so that the silicon steel strip is perpendicular to the direction of the magnetic field. The loaded current is a unilateral rectangular pulse current with a peak current of 185A, a time of 160s, a temperature of 380°C, a frequency of 40Hz, and a duty cycle of 60%.

[0067] Comparative Example 1: Modified polyaspartic acid was not added to the activation solution, and the rest was the same as in Example 1:

[0068] Step 1: cold rolling the silicon steel sheet to 0.02 mm using a four-roll mill, with a cold rolling reduction of 68% to obtain a silicon steel strip;

[0069] The silicon steel sheet is composed of the following components, calculated by mass fraction: 3 wt% silicon, 0.07 wt% manganese, 0.055 wt% aluminum, 0.30 wt% tin, 0.020 wt% phosphorus, 0.0025 wt% carbon, and the balance is iron;

[0070] Step 2: taking a silicon steel strip, cleaning and drying it to obtain a pretreated silicon steel strip; then placing the pretreated silicon steel strip in an activation solution for activation treatment, heating it to 108° C. and maintaining it for 13 hours to obtain an activated silicon steel strip;

[0071] The activation solution was prepared by mixing 210 mL of isopropyl alcohol and 30 mL of glycerol for 8 minutes, adding a mixture of 0.4 g of ferric nitrate nonahydrate, 0.35 g of zinc nitrate hexahydrate, 0.15 g of phytic acid, 0.1 g of urea, 0.15 g of sodium carbonate, and 10 mL of deionized water, and stirring under ultrasonication for 12 minutes to obtain the activation solution;

[0072] Step 3: using an immersion Czochralski method to prepare an anti-corrosion coating on the surface of the activated silicon steel strip using modified silica sol, and then performing a magnetic thermal coupling treatment and cooling to obtain a cold-rolled silicon steel strip;

[0073] The working conditions of the immersion pulling method are as follows: during pulling, the surface of the activated silicon steel strip is immersed in the modified silica sol for 50 seconds, the activated silicon steel strip is pulled out at a rate of 4500µm / s, and dried;

[0074] The preparation method of modified silica sol is:

[0075] S1: Take 1.4 g of trimesic acid, 4.4 g of ferric nitrate nonahydrate, and 40 mL of deionized water, stir evenly, add 1.4 mL of dilute nitric acid, heat to 117°C, react for 11 h, cool, filter, wash, and dry to obtain an iron-based organic framework material;

[0076] S2: Take 1 g of iron-based organic framework material and 200 mL of ethanol, stir evenly, add 2.2 g of benzotriazole, stir for 13 h, filter and dry to obtain the iron-based organic framework material loaded with corrosion inhibitor;

[0077] S3: 15 g of ethyl orthosilicate, 5 g of dodecyltriethoxysilane, and 46 g of anhydrous ethanol were mixed and stirred, 10 mL of deionized water and 1 g of an iron-based organic framework material loaded with a corrosion inhibitor were added, and ultrasonic stirring was performed for 8 min. The temperature was raised to 62°C and kept for 2 h to obtain a modified silica sol;

[0078] The working conditions of the magnetothermal coupling treatment are as follows: a silicon steel strip with an insulating coating is placed vertically in a quartz tube so that the silicon steel strip is perpendicular to the direction of the magnetic field. The loaded current is a unilateral rectangular pulse current with a peak current of 185A, a time of 160s, a temperature of 380°C, a frequency of 40Hz, and a duty cycle of 60%.

[0079] Comparative Example 2: No phytic acid was added to the activation solution, and the rest was the same as in Example 1:

[0080] Step 1: cold rolling the silicon steel sheet to 0.02 mm using a four-roll mill, with a cold rolling reduction of 68% to obtain a silicon steel strip;

[0081] The silicon steel sheet is composed of the following components, calculated by mass fraction: 3 wt% silicon, 0.07 wt% manganese, 0.055 wt% aluminum, 0.30 wt% tin, 0.020 wt% phosphorus, 0.0025 wt% carbon, and the balance is iron;

[0082] Step 2: taking a silicon steel strip, cleaning and drying it to obtain a pretreated silicon steel strip; then placing the pretreated silicon steel strip in an activation solution for activation treatment, heating it to 108° C. and maintaining it for 13 hours to obtain an activated silicon steel strip;

[0083] The activation solution was prepared by mixing 210 mL of isopropyl alcohol and 30 mL of glycerol for 8 minutes, adding a mixture of 0.4 g of ferric nitrate nonahydrate, 0.35 g of zinc nitrate hexahydrate, 0.3 g of modified polyaspartic acid, 0.1 g of urea, 0.15 g of sodium carbonate, and 10 mL of deionized water, and ultrasonically stirring for 12 minutes to obtain the activation solution;

[0084] The preparation method of the modified polyaspartic acid is:

[0085] 2 mL of dimethyl sulfoxide and 0.4 mL of triethylamine were added to 0.6 g of dopamine hydrochloride and stirred to obtain a mixed solution; 1 g of polysuccinimide and 20 mL of dimethyl sulfoxide were added to the mixed solution, nitrogen was passed through, the temperature was raised to 82°C, and the mixture was stirred for 24 h. 0.4 g of sodium hydroxide and 5 mL of deionized water were added and the mixture was reacted at 62°C for 24 h. 0.1 mol / L hydrochloric acid was added to adjust the pH to 6.0, the mixture was dialyzed, and lyophilized to obtain modified polyaspartic acid;

[0086] Step 3: using an immersion Czochralski method to prepare an anti-corrosion coating on the surface of the activated silicon steel strip using modified silica sol, and then performing a magnetic thermal coupling treatment and cooling to obtain a cold-rolled silicon steel strip;

[0087] The working conditions of the immersion pulling method are as follows: during pulling, the surface of the activated silicon steel strip is immersed in the modified silica sol for 50 seconds, the activated silicon steel strip is pulled out at a rate of 4500µm / s, and dried;

[0088] The preparation method of modified silica sol is:

[0089] S1: Take 1.4 g of trimesic acid, 4.4 g of ferric nitrate nonahydrate, and 40 mL of deionized water, stir evenly, add 1.4 mL of dilute nitric acid, heat to 117°C, react for 11 h, cool, filter, wash, and dry to obtain an iron-based organic framework material;

[0090] S2: Take 1 g of iron-based organic framework material and 200 mL of ethanol, stir evenly, add 2.2 g of benzotriazole, stir for 13 h, filter and dry to obtain the iron-based organic framework material loaded with corrosion inhibitor;

[0091] S3: 15 g of ethyl orthosilicate, 5 g of dodecyltriethoxysilane, and 46 g of anhydrous ethanol were mixed and stirred, 10 mL of deionized water and 1 g of an iron-based organic framework material loaded with a corrosion inhibitor were added, and ultrasonic stirring was performed for 8 min. The temperature was raised to 62°C and kept for 2 h to obtain a modified silica sol;

[0092] The working conditions of the magnetothermal coupling treatment are as follows: a silicon steel strip with an insulating coating is placed vertically in a quartz tube so that the silicon steel strip is perpendicular to the direction of the magnetic field. The loaded current is a unilateral rectangular pulse current with a peak current of 185A, a time of 160s, a temperature of 380°C, a frequency of 40Hz, and a duty cycle of 60%.

[0093] Comparative Example 3: Polyaspartic acid was not modified, and the rest was the same as Example 1:

[0094] Step 1: cold rolling the silicon steel sheet to 0.02 mm using a four-roll mill, with a cold rolling reduction of 68% to obtain a silicon steel strip;

[0095] The silicon steel sheet is composed of the following components, calculated by mass fraction: 3 wt% silicon, 0.07 wt% manganese, 0.055 wt% aluminum, 0.30 wt% tin, 0.020 wt% phosphorus, 0.0025 wt% carbon, and the balance is iron;

[0096] Step 2: taking a silicon steel strip, cleaning and drying it to obtain a pretreated silicon steel strip; then placing the pretreated silicon steel strip in an activation solution for activation treatment, heating it to 108° C. and maintaining it for 13 hours to obtain an activated silicon steel strip;

[0097] The activation solution was prepared by mixing 210 mL of isopropyl alcohol and 30 mL of glycerol for 8 minutes, adding a mixture of 0.4 g of ferric nitrate nonahydrate, 0.35 g of zinc nitrate hexahydrate, 0.15 g of phytic acid, 0.3 g of polyaspartic acid, 0.1 g of urea, 0.15 g of sodium carbonate, and 10 mL of deionized water, and stirring with ultrasound for 12 minutes to obtain the activation solution;

[0098] Step 3: using an immersion Czochralski method to prepare an anti-corrosion coating on the surface of the activated silicon steel strip using modified silica sol, and then performing a magnetic thermal coupling treatment and cooling to obtain a cold-rolled silicon steel strip;

[0099] The working conditions of the immersion pulling method are as follows: during pulling, the surface of the activated silicon steel strip is immersed in the modified silica sol for 50 seconds, the activated silicon steel strip is pulled out at a rate of 4500µm / s, and dried;

[0100] The preparation method of modified silica sol is:

[0101] S1: Take 1.4 g of trimesic acid, 4.4 g of ferric nitrate nonahydrate, and 40 mL of deionized water, stir evenly, add 1.4 mL of dilute nitric acid, heat to 117°C, react for 11 h, cool, filter, wash, and dry to obtain an iron-based organic framework material;

[0102] S2: Take 1 g of iron-based organic framework material and 200 mL of ethanol, stir evenly, add 2.2 g of benzotriazole, stir for 13 h, filter and dry to obtain the iron-based organic framework material loaded with corrosion inhibitor;

[0103] S3: 15 g of ethyl orthosilicate, 5 g of dodecyltriethoxysilane, and 46 g of anhydrous ethanol were mixed and stirred, 10 mL of deionized water and 1 g of an iron-based organic framework material loaded with a corrosion inhibitor were added, and ultrasonic stirring was performed for 8 min. The temperature was raised to 62°C and kept for 2 h to obtain a modified silica sol;

[0104] The working conditions of the magnetothermal coupling treatment are as follows: a silicon steel strip with an insulating coating is placed vertically in a quartz tube so that the silicon steel strip is perpendicular to the direction of the magnetic field. The loaded current is a unilateral rectangular pulse current with a peak current of 185A, a time of 160s, a temperature of 380°C, a frequency of 40Hz, and a duty cycle of 60%.

[0105] experiment:

[0106] The cold-rolled silicon steel strips prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to performance tests to test the contact angles of the cold-rolled silicon steel strips. Referring to GB / T1771-2017, the cold-rolled silicon steel strips were cut into 150 mm × 75 mm specimens and then placed in a salt spray chamber at a temperature of 35°C to observe their corrosion resistance. The data obtained are shown below:

[0107]

[0108] Conclusion: From the comparison of the data in the table, it can be seen that in Comparative Example 1, modified polyaspartic acid is not added to the activation solution, the loading rate of the iron-based organic framework material decreases, the corrosion resistance of the ultra-thin silicon steel strip decreases, and discoloration and rust appear after 1900h. In Comparative Example 2, phytic acid is not added to the activation solution, and it is unable to form a nanoporous structure with the modified polyaspartic acid, and the corrosion resistance of the ultra-thin silicon steel strip decreases. In Comparative Example 3, polyaspartic acid is not modified, and the chelating property of polyaspartic acid decreases, affecting the decrease in the corrosion resistance of the ultra-thin silicon steel strip. Examples 1 to 3 of the present invention add phytic acid and modified polyaspartic acid to the activation solution. Using polysuccinimide as a raw material and adding dopamine for grafting modification, a polymer with polyaspartic acid as a skeleton and grafted dopamine is obtained. The dopamine has a catechol group, which further enhances the chelating property of polyaspartic acid for metal ions on the iron-based organic framework material. At the same time, phytic acid is added to the activation solution. Phytic acid can form a nanoporous structure with modified polyaspartic acid, which is beneficial to the subsequent loading of modified silica sol, thereby further enhancing the corrosion resistance of the ultra-thin silicon steel strip.

[0109] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A method for processing a cold-rolled silicon steel strip, characterized in that: The following steps are involved: Step 1: cold rolling the silicon steel sheet to obtain a silicon steel strip; Step 2: Take a silicon steel strip, clean and dry it to obtain a pretreated silicon steel strip; then place the pretreated silicon steel strip in an activation solution for activation treatment, heat it to 105-110° C. and keep it warm for 12-14 hours to obtain an activated silicon steel strip; Step 3: using an immersion Czochralski method to prepare an anti-corrosion coating on the surface of the activated silicon steel strip using modified silica sol, and then performing a magnetic thermal coupling treatment and cooling to obtain a cold-rolled silicon steel strip; Preparation of activation solution The method comprises the following steps: mixing isopropyl alcohol and glycerol for 5-10 minutes, adding a mixture of ferric nitrate nonahydrate, zinc nitrate hexahydrate, phytic acid, modified polyaspartic acid, urea, sodium carbonate and deionized water, and ultrasonically stirring for 10-15 minutes to obtain an activation solution; The modified silica sol is prepared by mixing ethyl orthosilicate, dodecyltriethoxysilane, and anhydrous ethanol, adding deionized water and an iron-based organic framework material loaded with a corrosion inhibitor, stirring the mixture ultrasonically for 5-10 minutes, heating the mixture to 60-65° C. and maintaining the temperature for 1-3 hours to obtain the modified silica sol. The preparation method of the corrosion inhibitor-loaded iron-based organic framework material is: The following steps are involved: S1: Take trimesic acid, ferric nitrate nonahydrate, and deionized water, stir evenly, add dilute nitric acid, heat to 115-120°C, react for 10-12 hours, cool, filter, wash, and dry to obtain an iron-based organic framework material; S2: Take the iron-based organic framework material and ethanol, stir them evenly, add benzotriazole, stir for 12-14 hours, filter and dry to obtain the iron-based organic framework material loaded with corrosion inhibitor; The modified polyaspartic acid preparation method comprises: taking dimethyl sulfoxide and triethylamine, adding dopamine hydrochloride, and stirring evenly to obtain a mixed solution; taking polysuccinimide and dimethyl sulfoxide, stirring evenly, adding the mixed solution, passing nitrogen, heating to 80-85° C., stirring for 22-26 hours, adding sodium hydroxide and deionized water, reacting at 60-65° C. for 22-26 hours, adding hydrochloric acid, adjusting the pH value to 6.0-6.2, dialyzing, and freeze-drying to obtain the modified polyaspartic acid; The silicon steel sheet is composed of the following components, calculated by mass fraction: 2.5wt%-3.5wt% silicon, 0.06wt%-0.10wt% manganese, 0.05wt%-0.06wt% aluminum, 0.25wt%-0.034wt% tin, 0.018wt%-0.022wt% phosphorus, 0.002wt%-0.003wt% carbon, and the balance is iron.

2. The method for processing a cold-rolled silicon steel strip according to claim 1, wherein: The silicon steel sheet is composed of the following components, calculated by mass fraction: 3.0wt%-3.3wt% silicon, 0.08wt%-0.10wt% manganese, 0.05wt%-0.06wt% aluminum, 0.3wt%-0.032wt% tin, 0.018wt%-0.020wt% phosphorus, 0.002wt%-0.003wt% carbon, and the balance is iron.

3. The method for processing a cold-rolled silicon steel strip according to claim 1, wherein: The working conditions of the immersion pulling method are as follows: during pulling, the surface of the activated silicon steel strip is immersed in the modified silica sol for 40-60 seconds, the activated silicon steel strip is pulled out at a speed of 4500 μm / s, and then dried.

4. A cold-rolled silicon steel strip obtained by processing the cold-rolled silicon steel strip according to any one of claims 1 to 3.

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