Cold-rolled silicon steel thin strip and processing method thereof

Abstract

The invention discloses a cold-rolled silicon steel thin strip and a processing method thereof, and relates to the technical field of silicon steel strips. According to the method, the silicon steel plate is cold-rolled into the ultrathin silicon steel strip, then the ultrathin silicon steel strip is subjected to activating treatment through the activating solution and then coated with the anti-corrosion coating, and the prepared ultrathin silicon steel strip has good corrosion resistance. According to the invention, phytic acid and modified polyaspartic acid are added into an activating solution. According to the iron-based organic framework material, polysuccinimide is used as a raw material, dopamine is added for grafting modification, a polymer which takes polyaspartic acid as a framework and is grafted with dopamine is obtained, the dopamine has a catechol group, and the chelating property of the polyaspartic acid to metal ions on the iron-based organic framework material is further enhanced. And meanwhile, phytic acid is added into the activating solution, the phytic acid and the modified polyaspartic acid can form a nano-porous structure, loading of subsequent modified silica sol is facilitated, and therefore the corrosion resistance of the ultra-thin silicon steel strip is further enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of silicon steel strips, in particular to a cold-rolled silicon steel thin 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. Silicon steel increases the resistivity of iron-based alloys and reduces eddy current losses by adding silicon elements, thereby showing good 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 good processability. The cold-rolled silicon steel strip has good ductility and processing performance, and is suitable for the manufacture of electromagnetic components of various complex shapes. However, in long-term use, silicon steel strip is easily corroded by corrosive media, which leads to a decrease in service life.

[0003] In order to solve the above problems and improve the corrosion resistance of silicon steel strip, 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 to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions: A method for processing a cold-rolled silicon steel strip comprises the following steps: 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 for 12-14 hours to obtain an activated silicon steel strip; Step 3: using an immersion pulling 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; The preparation of the activation solution includes the following steps: mixing isopropanol 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.

[0006] More optimally, the preparation method of the modified polyaspartic acid is: 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 22-26h, add sodium hydroxide and deionized water, react at 60-65°C for 22-26h, add hydrochloric acid, adjust the pH value to 6.0-6.2, dialyze, and freeze-dry to obtain modified polyaspartic acid.

[0007] More optimally, the preparation method of the modified silica sol is: mix and stir ethyl orthosilicate, dodecyltriethoxysilane and anhydrous ethanol, add deionized water and iron-based organic framework material loaded with corrosion inhibitor, ultrasonically stir for 5-10 minutes, heat to 60-65°C and keep warm for 1-3 hours to obtain modified silica sol.

[0008] More optimally, the method for preparing the corrosion inhibitor-loaded iron-based organic framework material comprises the following steps: S1: Take trimesic acid, ferric nitrate nonahydrate and deionized water, stir evenly, add dilute nitric acid, heat to 115-120°C, react for 10-12h, cool, filter, wash and dry to obtain an iron-based organic framework material; S2: Take an iron-based organic framework material and ethanol, stir evenly, add benzotriazole, stir for 12-14 hours, filter and dry to obtain an iron-based organic framework material loaded with a corrosion inhibitor.

[0009] 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.

[0010] 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, and the activated silicon steel strip is pulled out at a rate of 4500 μm / s and dried.

[0011] 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.

[0012] Compared with the prior art, the present invention has the following beneficial effects: (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.

[0013] (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 skeleton and grafted dopamine is obtained. Dopamine has a catechol group, which further enhances the chelation of polyaspartic acid to metal ions on the iron-based organic skeleton 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.

[0014] (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 to enhance 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, thereby enhancing the corrosion resistance of the ultra-thin silicon steel strip. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] The sources and purchase channels of the raw materials involved in the present invention are not subject to any particular restrictions, and exemplary examples include: polysuccinimide: can be purchased from McLean, model: P871967; amino-terminated polyethylene glycol: can be purchased from McLean, model: N902461.

[0017] Embodiment 1: A method for processing a cold-rolled silicon steel strip, comprising the following steps: Step 1: cold-roll the silicon steel sheet to 0.02 mm using a four-roll rolling mill, with a cold rolling reduction rate of 68% to obtain a silicon steel strip; The silicon steel sheet is composed of the following components, calculated by mass fraction: 3wt% silicon, 0.07wt% manganese, 0.055wt% aluminum, 0.30wt% tin, 0.020wt% phosphorus, 0.0025wt% carbon, and the balance is iron; 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 108° C. and keep it warm for 13 hours to obtain an activated silicon steel strip; The preparation of the activation solution comprises the following steps: 210 mL of isopropanol and 30 mL of glycerol are mixed and stirred for 8 minutes, 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 are added, and ultrasonic stirring is performed for 12 minutes to obtain the activation solution; The preparation method of the modified polyaspartic acid is: Take 2 mL of dimethyl sulfoxide and 0.4 mL of triethylamine, add 0.6 g of dopamine hydrochloride, stir evenly to obtain a mixed solution; take 1 g of polysuccinimide and 20 mL of dimethyl sulfoxide, stir evenly, add the mixed solution, pass nitrogen, heat to 82°C, stir for 24 h, add 0.4 g of sodium hydroxide and 5 mL of deionized water, react at 62°C for 24 h, add hydrochloric acid with a concentration of 0.1 mol / L, adjust the pH value to 6.0, dialyze, and freeze-dry to obtain modified polyaspartic acid; Step 3: using an immersion pulling 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; 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; The preparation method of modified silica sol is: 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; S2: Take 1 g of the 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; 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 8 min, and the temperature was raised to 62 ° C and kept for 2 h to obtain a modified silica sol; The working conditions of the magnetothermal coupling treatment are as follows: the 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%.

[0018] Embodiment 2: A method for processing a cold-rolled silicon steel strip, comprising the following steps: Step 1: cold-roll the silicon steel sheet to 0.02 mm using a four-roll rolling mill, with a cold rolling reduction rate of 68% to obtain a silicon steel strip; 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; 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° C. and keep it warm for 12 hours to obtain an activated silicon steel strip; The preparation of the activation solution comprises the following steps: 210 mL of isopropanol and 30 mL of glycerol are mixed and stirred for 5 minutes, 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 are added, and ultrasonic stirring is performed for 10 minutes to obtain the activation solution; The preparation method of the modified polyaspartic acid is: Take 2 mL of dimethyl sulfoxide and 0.4 mL of triethylamine, add 0.6 g of dopamine hydrochloride, stir evenly to obtain a mixed solution; take 1 g of polysuccinimide and 20 mL of dimethyl sulfoxide, stir evenly, add the mixed solution, pass nitrogen, heat to 80°C, stir for 22 h, add 0.4 g of sodium hydroxide and 5 mL of deionized water, react at 60°C for 22 h, add hydrochloric acid with a concentration of 0.1 mol / L, adjust the pH value to 6.0, dialyze, and freeze-dry to obtain modified polyaspartic acid; Step 3: using an immersion pulling 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; 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; The preparation method of modified silica sol is: 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 and react for 10 h, cool, filter, wash, and dry to obtain an iron-based organic framework material; S2: Take 1 g of the iron-based organic framework material and 200 mL of ethanol, stir evenly, add 2.2 g of benzotriazole, stir for 12 h, filter and dry to obtain the iron-based organic framework material loaded with corrosion inhibitor; 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 the temperature was raised to 60 ° C and kept for 1 h to obtain a modified silica sol; The working conditions of the magnetothermal coupling treatment are as follows: the 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%.

[0019] Embodiment 3: A method for processing a cold-rolled silicon steel strip, comprising the following steps: Step 1: cold-roll the silicon steel sheet to 0.02 mm using a four-roll rolling mill, with a cold rolling reduction rate of 68% to obtain a silicon steel thin strip; The silicon steel sheet is composed of the following components, calculated by mass fraction: 3.5wt% silicon, 0.10wt% manganese, 0.06wt% aluminum, 0.034wt% tin, 0.022wt% phosphorus, 0.003wt% carbon, and the balance is iron; 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 110° C. and keep it warm for 14 hours to obtain an activated silicon steel strip; The preparation of the activation solution comprises the following steps: 210 mL of isopropanol and 30 mL of glycerol are mixed and stirred for 10 minutes, 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 are added, and ultrasonic stirring is performed for 15 minutes to obtain the activation solution; The preparation method of the modified polyaspartic acid is: Take 2 mL of dimethyl sulfoxide and 0.4 mL of triethylamine, add 0.6 g of dopamine hydrochloride, stir evenly to obtain a mixed solution; take 1 g of polysuccinimide and 20 mL of dimethyl sulfoxide, stir evenly, add the mixed solution, pass nitrogen, heat to 85°C, stir for 26 hours, add 0.4 g of sodium hydroxide and 5 mL of deionized water, react at 65°C for 26 hours, add hydrochloric acid with a concentration of 0.1 mol / L, adjust the pH value to 6.2, dialyze, and freeze-dry to obtain modified polyaspartic acid; Step 3: using an immersion pulling 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; 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; The preparation method of modified silica sol is: 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; S2: Take 1 g of the 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; 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 the temperature was raised to 65 ° C and kept for 3 h to obtain a modified silica sol; The working conditions of the magnetothermal coupling treatment are as follows: the 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%.

[0020] Comparative Example 1: Modified polyaspartic acid is not added to the activation solution, and the rest is the same as Example 1: Step 1: cold-roll the silicon steel sheet to 0.02 mm using a four-roll rolling mill, with a cold rolling reduction rate of 68% to obtain a silicon steel strip; The silicon steel sheet is composed of the following components, calculated by mass fraction: 3wt% silicon, 0.07wt% manganese, 0.055wt% aluminum, 0.30wt% tin, 0.020wt% phosphorus, 0.0025wt% carbon, and the balance is iron; 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 108° C. and keep it warm for 13 hours to obtain an activated silicon steel strip; The preparation of the activation solution comprises the following steps: 210 mL of isopropanol and 30 mL of glycerol are mixed and stirred for 8 minutes, 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 are added, and ultrasonic stirring is performed for 12 minutes to obtain the activation solution; Step 3: using an immersion pulling 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; 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; The preparation method of modified silica sol is: 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; S2: Take 1 g of the 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; 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 8 min, and the temperature was raised to 62 ° C and kept for 2 h to obtain a modified silica sol; The working conditions of the magnetothermal coupling treatment are as follows: the 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%.

[0021] Comparative Example 2: No phytic acid is added to the activation solution, and the rest is the same as Example 1: Step 1: cold-roll the silicon steel sheet to 0.02 mm using a four-roll rolling mill, with a cold rolling reduction rate of 68% to obtain a silicon steel strip; The silicon steel sheet is composed of the following components, calculated by mass fraction: 3wt% silicon, 0.07wt% manganese, 0.055wt% aluminum, 0.30wt% tin, 0.020wt% phosphorus, 0.0025wt% carbon, and the balance is iron; 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 108° C. and keep it warm for 13 hours to obtain an activated silicon steel strip; The preparation of the activation solution comprises the following steps: 210 mL of isopropanol and 30 mL of glycerol are mixed and stirred for 8 min, 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 are added into the mixture, and ultrasonic stirring is performed for 12 min to obtain the activation solution; The preparation method of the modified polyaspartic acid is: Take 2 mL of dimethyl sulfoxide and 0.4 mL of triethylamine, add 0.6 g of dopamine hydrochloride, stir evenly to obtain a mixed solution; take 1 g of polysuccinimide and 20 mL of dimethyl sulfoxide, stir evenly, add the mixed solution, pass nitrogen, heat to 82°C, stir for 24 h, add 0.4 g of sodium hydroxide and 5 mL of deionized water, react at 62°C for 24 h, add hydrochloric acid with a concentration of 0.1 mol / L, adjust the pH value to 6.0, dialyze, and freeze-dry to obtain modified polyaspartic acid; Step 3: using an immersion pulling 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; 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; The preparation method of modified silica sol is: 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; S2: Take 1 g of the 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; 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 8 min, and the temperature was raised to 62 ° C and kept for 2 h to obtain a modified silica sol; The working conditions of the magnetothermal coupling treatment are as follows: the 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%.

[0022] Comparative Example 3: Polyaspartic acid was not modified, and the rest was the same as Example 1: Step 1: cold-roll the silicon steel sheet to 0.02 mm using a four-roll rolling mill, with a cold rolling reduction rate of 68% to obtain a silicon steel strip; The silicon steel sheet is composed of the following components, calculated by mass fraction: 3wt% silicon, 0.07wt% manganese, 0.055wt% aluminum, 0.30wt% tin, 0.020wt% phosphorus, 0.0025wt% carbon, and the balance is iron; 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 108° C. and keep it warm for 13 hours to obtain an activated silicon steel strip; The preparation of the activation solution comprises the following steps: 210 mL of isopropanol and 30 mL of glycerol are mixed and stirred for 8 minutes, 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 are added, and ultrasonic stirring is performed for 12 minutes to obtain the activation solution; Step 3: using an immersion pulling 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; 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; The preparation method of modified silica sol is: 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; S2: Take 1 g of the 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; 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 8 min, and the temperature was raised to 62 ° C and kept for 2 h to obtain a modified silica sol; The working conditions of the magnetothermal coupling treatment are as follows: the 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%.

[0023] experiment: 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 as follows:

[0024] 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 occur after 1900h. Comparative Example 2 does not add phytic acid to the activation solution, and it is impossible to form a nanoporous structure with modified polyaspartic acid, and the corrosion resistance of the ultra-thin silicon steel strip decreases. Comparative Example 3 does not modify polyaspartic acid, and the chelating property of polyaspartic acid decreases, which affects the decrease in the corrosion resistance of the ultra-thin silicon steel strip. Phytic acid and modified polyaspartic acid are added to the activation solution in Examples 1 to 3 of the present invention. 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, and dopamine has a catechol group, which further enhances the chelating property of polyaspartic acid to 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.

[0025] 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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

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 for 12-14 hours to obtain an activated silicon steel strip; Step 3: using an immersion pulling 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 isopropanol 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.

2. The method for processing a cold-rolled silicon steel strip according to claim 1, characterized in that: The preparation method of the modified polyaspartic acid is as follows: taking dimethyl sulfoxide and triethylamine, adding dopamine hydrochloride, 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.

3. The method for processing a cold-rolled silicon steel strip according to claim 1, characterized in that: The preparation method of the modified silica sol is as follows: ethyl orthosilicate, dodecyltriethoxysilane and anhydrous ethanol are mixed and stirred, deionized water and an iron-based organic framework material loaded with a corrosion inhibitor are added, ultrasonic stirring is performed for 5-10 minutes, and the temperature is raised to 60-65° C. and kept for 1-3 hours to obtain the modified silica sol.

4. The method for processing a cold-rolled silicon steel strip according to claim 3, characterized in that: The preparation method of the iron-based organic framework material loaded with corrosion inhibitor 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 10-12h, cool, filter, wash and dry to obtain an iron-based organic framework material; S2: Take an iron-based organic framework material and ethanol, stir evenly, add benzotriazole, stir for 12-14 hours, filter and dry to obtain an iron-based organic framework material loaded with a corrosion inhibitor.

5. The method for processing a cold-rolled silicon steel strip according to claim 1, characterized in that: 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.

6. The method for processing a cold-rolled silicon steel strip according to claim 1, characterized in that: 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, and the activated silicon steel strip is pulled out at a rate of 4500 μm / s and dried.

7. The method for processing a cold-rolled silicon steel strip according to claim 5, characterized in that: 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.

8. A cold-rolled silicon steel strip obtained by processing the cold-rolled silicon steel strip according to any one of claims 1 to 7.

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