CN117000562A - Production method of unoriented silicon steel for improving insulation of large-sized generator iron core and product prepared by production method - Google Patents

Production method of unoriented silicon steel for improving insulation of large-sized generator iron core and product prepared by production method Download PDF

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Publication number
CN117000562A
CN117000562A CN202310806855.2A CN202310806855A CN117000562A CN 117000562 A CN117000562 A CN 117000562A CN 202310806855 A CN202310806855 A CN 202310806855A CN 117000562 A CN117000562 A CN 117000562A
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China
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coating
silicon steel
oriented silicon
annealing
equal
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祁旋
夏雪兰
陈明侠
裴英豪
施立发
刘青松
陆天林
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Maanshan Iron and Steel Co Ltd
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Maanshan Iron and Steel Co Ltd
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Priority to CN202310806855.2A priority Critical patent/CN117000562A/en
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D1/00—Processes for applying liquids or other fluent materials
    • B05D1/36—Successively applying liquids or other fluent materials, e.g. without intermediate treatment
    • B05D1/38—Successively applying liquids or other fluent materials, e.g. without intermediate treatment with intermediate treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
    • B05D5/10—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain an adhesive surface
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
    • B05D5/12—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain a coating with specific electrical properties
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    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/50—Multilayers
    • B05D7/52—Two layers
    • B05D7/54—No clear coat specified
    • B05D7/546—No clear coat specified each layer being cured, at least partially, separately
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
    • C21D8/1222—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
    • C21D8/1233—Cold rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1244—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest
    • C21D8/1272—Final recrystallisation annealing
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
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    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D2202/00—Metallic substrate
    • B05D2202/10—Metallic substrate based on Fe
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
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    • B05D2502/00—Acrylic polymers
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Abstract

The invention discloses a production method of unoriented silicon steel for improving insulation of a large-sized generator iron core and a product prepared by the production method, and belongs to the technical field of large-sized generators. The method comprises the steps of carrying out primary coating of magnesium chromate insulating paint through a coating roller after strip steel annealing, reducing to 100-200 ℃ after solidification, carrying out oily secondary painting coating, and improving technological methods and parameters in the production process aiming at the coating of the oily secondary painting. The magnetic property of the prepared product meets the iron loss P 1.5/50 Less than or equal to 3.0W/Kg and magnetic induction B 50 More than or equal to 1.66T, and the interlayer resistance is more than 10000 Ω & mm 2 The tablet can meet the heat-resistant requirement of 155 ℃ multiplied by 48h (grade F).

Description

Production method of unoriented silicon steel for improving insulation of large-sized generator iron core and product prepared by production method
Technical Field
The invention belongs to the technical field of non-oriented silicon steel production, and particularly relates to a production method of non-oriented silicon steel for improving insulation of a large generator iron core and a product prepared by the production method.
Background
Silicon steel is a raw material for producing various rotating electrical machines, transformers, generators, etc., and is an important soft magnetic alloy material in the power, electronics, military industries and vehicles. In the application, the coating on the surface of the non-oriented silicon steel can play an insulating role to prevent short circuit from occurring between iron core lamination sheets to increase eddy current loss, thereby preventing deterioration of electromagnetic performance. For the industries of common medium and small motors, compressors, industrial motors and the like, the requirement on the insulating coating on the surface of silicon steel is relatively low, the thickness of the magnesium chromate coating on the surface of non-oriented silicon steel produced by the existing mainstream steel mill is 0.5-1.0 mu m, and the thickness of the magnesium chromate coating is between layersThe resistance is generally 200Ω·mm 2 And/or the tablet can meet the requirements of the related field.
However, in the field of large-scale generators such as hydroelectric, thermal and nuclear power generators, the requirements on insulation performance are high, and the interlayer resistance is generally more than 10000 Ω & mm 2 The existing magnesium chromate coating is difficult to meet the use requirement, generally a C5 thick coating or an extremely thick coating is adopted, for example, patent CN1903498A, but the adhesive force of the coating is greatly reduced if the coating quantity is too large, and the requirement of a large-scale generator on the high adhesive strength of the coating is not met. Or the interlayer resistance of the silicon steel sheet is increased by adopting a secondary painting mode on the surface of the silicon steel before the use of the silicon steel sheet.
Patent CN115739569a discloses a secondary coating method of electrical steel self-adhesive coating, which is just used for directly coating the self-adhesive coating on the original insulating coating or the failed self-adhesive coating, and the self-adhesive coating is used for fixing the iron core lamination, and welding or riveting is not needed, unlike the component system and the function of the invention. Patent CN103692726a discloses a chromium-free insulating coated electrical steel and a method for producing the same, the coating performance of which is similar to that of the traditional chromium-containing coating, which is different from the component system of the present invention. None of the above coatings has the effect of increasing the interlayer resistance. Patent CN115595010a discloses a non-oriented silicon steel insulating coating liquid for improving secondary coating of electrophoretic paint, a preparation method and application, and does not disclose a coating process, so that an effect of effectively increasing interlayer resistance cannot be obtained.
Disclosure of Invention
1. Problems to be solved
Aiming at the problem that the coating in the prior art cannot effectively increase the interlayer resistance, the invention provides a production method of non-oriented silicon steel for improving the insulation of a large-sized generator iron core and a product prepared by the production method, which can effectively improve the interlayer resistance of silicon steel and further improve the surface insulation.
2. Technical proposal
In order to solve the problems, the technical scheme adopted by the invention is as follows:
the invention relates to non-oriented silicon steel for improving the insulation property of a large generator iron core and a production method thereof, which belong to high-grade non-oriented silicon steel. The product is characterized in that:
the chemical components of the slab in percentage by weight (%) comprise: c is less than or equal to 0.003%, si:2.8 to 3.4 percent, mn:0.15 to 0.45 percent, als:0.5 to 1.0 percent, S is less than or equal to 0.003 percent, N is less than or equal to 0.003 percent, ti is less than or equal to 0.003 percent, and the balance is Fe and unavoidable impurities;
wherein the elements function in the steel as follows:
si: the Si element can improve the resistivity and reduce the iron loss of the product, but simultaneously the magnetic induction is also reduced, the application field of the non-oriented silicon steel produced by the method is the field of large-scale generators such as hydropower, wind power, nuclear power and the like, the high-grade non-oriented silicon steel is required to have the Si content of more than or equal to 2.8 percent, and meanwhile, the cold rolling is ensured to be smooth, and the magnetic induction of the non-oriented silicon steel is required to have the Si content of less than or equal to 3.4 percent.
Mn: mn and S element form MnS, which has the effect of reducing solid solution S when a slab is heated, can well inhibit the hot embrittlement phenomenon in the heating process, but if the Mn content is too high, tiny MnS precipitates are generated during hot rolling, thereby preventing crystal grains from growing, deteriorating magnetic performance, and the Mn content is required to be less than or equal to 0.45 percent, so the Mn content is controlled to be 0.15 to 0.35 percent.
Als: the Al element is similar to the Si element, so that the magnetic performance of the product can be improved, the iron loss of the product can be reduced, but the magnetic induction of the product is reduced, the Als is required to be more than or equal to 0.5 percent in order to ensure the magnetic performance of the product, but the Al content is high, the adhesion of a secondary painting coating is reduced on an oxide layer of a product on the surface of strip steel, and the Als is required to be less than or equal to 1.0 percent in order to ensure the magnetic induction of the product and the stability of the secondary painting performance of the product.
C. S, N, ti: C. s, N, ti is a harmful element, and in order to reduce the influence on the magnetic performance of the product, the content of S is less than or equal to 0.003%, the content of N is less than or equal to 0.003%, and the content of Ti is less than or equal to 0.003%.
The production method of the unoriented silicon steel comprises the following steps:
step S1, continuous casting: molten steel is continuously cast into a plate blank with the thickness of 200-260 mm.
Step S2, heating: the slab is directly loaded into a heating furnace for heating, the temperature of the heating furnace is controlled to 1150-1250 ℃, the total heating time is 210-230 min, the temperature of the heating furnace has an influence on the magnetic performance of the product, and the magnetic performance of the product can be improved.
Step S3, hot rolling: the plate blank is finish rolled to a hot rolled plate with the thickness of 2.2-2.6 mm, the finishing temperature is 860-920 ℃, and the coiling temperature is 650-700 ℃.
Step S4, pickling and normalizing: the hot rolled sheet is normalized at 850-900 ℃ after shot blasting and acid washing, in order to ensure that the magnetic induction B50 is more than or equal to 1.66T, the normalizing temperature is more than or equal to 850 ℃, the higher the magnetic induction is required by the non-oriented silicon steel, the better the normalizing temperature is, the higher the magnetic induction is, and the component system considers that the B50 is more than or equal to 1.66T, the normalizing temperature is not lower than 850 ℃, but the temperature is too high, the cold rolling is not facilitated, and the normalizing temperature is less than or equal to 900 ℃ in order to ensure the smooth running of the cold rolling.
Step S5, cold rolling: the normalized sheet is cold rolled to the target thickness of 0.50mm, the surface of the finished product is considered to be secondarily painted, in order to improve the coating adhesive force after the secondary painting of the surface, a rough roller is adopted for a roller, and the surface concave-convex area of the roller is orderly arranged, and the surface roughness Ra of the strip steel is more than 0.8 mu m after cold rolling is ensured by laser irradiation, plasma flame treatment or chemical erosion before the roller is used, the coating capability is improved by increasing the surface roughness, the coating adhesive force and the interlayer resistance after the coating can not meet the high requirement of a large generator on the coating interlayer resistance if the surface roughness is too small, the influence of the strip steel surface roughness on the coating adhesive force is larger, the traditional primary coating performance requirement is low, and the roughness is generally not required, but the larger interlayer resistance is required.
Step S6, alkali washing: the cold-rolled sheet is continuously annealed, the strip steel before annealing is passed through an alkali liquor tank with the temperature of 70-80 ℃ and the pH value is required to be 9-11, so that rolling oil and dirt on the surface of the strip steel are removed, the surface of the strip steel is ensured to be cleaned, and impurities such as iron scales and the like which affect the adhesiveness of the coating are avoided.
Step S7, annealing: the atmosphere in the continuous annealing furnace is the mixture of hydrogen and nitrogen, H 2 And N 2 The ratio of (3) to (7) is considered to be in the field of high brands, the alloy content is high, the oxidation is easy, and the furnace atmosphere adopts dry atmosphere. The temperature of the soaking section of the annealing furnace is 950-1000 ℃, the annealing temperature is increased, the iron loss of the product can be reduced, and the magnetic induction is also reduced at the same time, so as to ensure the product P 1.5/50 Not more than 3.0W/Kg, the annealing temperature is not less than 950 ℃, but the magnetic induction B is ensured 50 The temperature is more than or equal to 1.66T, the required annealing temperature is less than or equal to 950 ℃, and the annealing time is 240-480 s.
Step S8, primary coating: the strip steel is annealed and then is coated with magnesium chromate insulating paint once by a coating roller, the insulating paint is cured at 500-600 ℃, the curing temperature is required to be more than or equal to 500 ℃ for ensuring the curing of the primary coating, and the curing temperature is required to be less than or equal to 600 ℃ for preventing the occurrence of overburning. Cooling the strip steel by adopting air cooling after solidification, wherein the cooling speed is required to be less than or equal to 20 ℃/s in order to reduce the deterioration of internal stress caused by cooling on magnetic performance. The magnesium-based chromate insulating coating comprises magnesium salt, chromate, latex resin solution and surfactant. The latex resin solution comprises one or more of butadiene and propylene ethylene acetic acid, and the surfactant comprises one or more of acrylate homopolymers and copolymers. Wherein, the magnesium salt content is 10-20%, the chromate is 10-20%, the other component system is 30-80%, the solid content of the paint is more than or equal to 20%, the secondary painting has certain matching property with the primary painting, and the stability of the primary painting performance needs to be ensured in order to ensure the performance of the secondary painting.
Step S9, secondary coating: and (3) reducing the temperature of the strip steel to 100-200 ℃ and then carrying out oil secondary painting coating.
The secondary paint is mainly prepared from epoxy resin, phenolic resin, aromatic amine or anhydride and an organic solvent, wherein the epoxy resin content is 15-25%, the phenolic resin content is 5-15%, the aromatic amine or anhydride content is 5-15%, and the balance is the organic solvent, so that the solid content of the oily secondary paint is more than or equal to 30%. The organic solvent is one or more of dimethylbenzene or benzene. The film forming agent epoxy resin mainly plays a role in cohesiveness in the film forming process, and is better attached to the surface of a metal or nonmetal material, so that the adhesive force of a coating is improved; phenolic resin mainly plays a role in improving the heat resistance of the coating; aromatic amines or anhydrides mainly play a role in curing. The oily secondary paint is cured at 300-350 ℃ after being coated, the curing temperature is more than or equal to 300 ℃ for ensuring the full curing of the secondary paint, meanwhile, the adhesive force of the coating is reduced for preventing the secondary paint from being over-burned, the curing temperature is less than or equal to 350 ℃, the curing time is 30-50 s, the paint cannot be cured, and the adhesive force, interlayer resistance and heat resistance of the coating cannot meet the requirements. Excessive temperature can cause excessive burning phenomenon, and the adhesive force of the coating is affected. The surface of the finished product after curing is dark yellow, as shown in figure 1.
The weight of the coating film for producing the oily secondary painting high-grade non-oriented silicon steel is 0.8-1.0 g/m 2 The thickness of the coating is 3-6 mu m, the pencil hardness of the coating is more than 9H, the adhesive force of the coating is A level, and the interlayer resistance is more than 10000 omega mm 2 The tablet can meet the heat-resistant requirement of 155 ℃ multiplied by 48h (grade F), and the highest heat-resistant grade can reach 175 ℃ multiplied by 48h, so that the coating does not fall off. The morphology of the coating under the aging process condition of 175 ℃ multiplied by 48 hours is shown in figure 2.
The invention selects the secondary painting of epoxy resin, phenolic resin, aromatic amine or anhydride as the raw material of the secondary painting, and controls the surface roughness Ra of the cold-rolled strip steel to be more than 0.8 mu m and the curing temperature of the painting at the same time in order to improve the coating performance of the secondary painting. Further, during primary painting, als is controlled to be more than or equal to 0.5% and less than or equal to 1.0% in the slab, the Als is controlled to be lower in content, and the stability of secondary painting is improved.
The oily secondary painting high-grade non-oriented silicon steel product obtained by said invented process has high inter-layer resistance between silicon steel sheets, excellent coating adhesion, high heat-resisting grade and high coating hardness, and the inter-layer resistance is greater than 10000 Ω -mm 2 The tablet can meet the heat-resistant requirement of 155 ℃ multiplied by 48h (grade F). At the same time, the magnetic property satisfies the iron loss P 1.5/50 Less than or equal to 3.0W/Kg and magnetic induction B 50 And the magnetic property is excellent and is more than or equal to 1.66T. Meets the magnetic property of the large-scale generator iron core to the silicon steel sheet and the insulativity to the silicon steel sheetHigh requirements for energy, adhesion strength and heat resistance.
3. Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
the invention provides non-oriented silicon steel for improving the surface interlayer resistance of non-oriented silicon steel for a large generator, which is characterized in that the surface of an original magnesium chromate coating is coated with an oily secondary paint, so that the surface insulation of the silicon steel can be improved, the bonding strength is excellent, the surface insulation of the silicon steel can be improved, the bonding strength, the hardness and the heat resistance are high, and the requirements of the large generator iron core on the high insulation performance between silicon steel sheets, the bonding strength and the heat resistance can be met.
Drawings
The technical solution of the present invention will be described in further detail below with reference to the accompanying drawings and examples, but it should be understood that these drawings are designed for the purpose of illustration only and thus are not limiting the scope of the present invention. Moreover, unless specifically indicated otherwise, the drawings are intended to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.
FIG. 1 is a graph of surface topography after 300 ℃ x 50s curing of an oily secondary paint;
FIG. 2 is a graph showing the appearance of a coating after being cross-hatched at 160 ℃ for 48 hours after oil-based secondary painting;
FIG. 3 is a graph of surface topography after oil-based secondary painting, 370 ℃ x 60s curing;
fig. 4 is a graph showing the morphology of the coating after the oil-based secondary painting is performed at 145 ℃ for 48 hours and then the coating is diced.
Detailed Description
The following detailed description of exemplary embodiments of the invention refers to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration exemplary embodiments in which the invention may be practiced. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it is to be understood that other embodiments may be realized and that various changes to the invention may be made without departing from the spirit and scope of the invention. The following more detailed description of the embodiments of the invention is not intended to limit the scope of the invention, as claimed, but is merely illustrative and not limiting of the invention's features and characteristics in order to set forth the best mode of carrying out the invention and to sufficiently enable those skilled in the art to practice the invention. Accordingly, the scope of the invention is limited only by the attached claims.
Example 1
The non-oriented silicon steel for improving the insulation property of the large generator iron core and the production method thereof specifically comprise the following steps:
step S1, continuous casting: continuously casting the molten steel refined by the RH furnace into a plate blank with the thickness of 230mm, wherein the chemical components of the plate blank are respectively as follows by weight percentage: 0.003%; si:2.80%; mn:0.15%; als:0.50%; s:0.003%, N:0.003%, ti:0.003% of Fe and the balance of unavoidable impurity elements.
Step S2, heating: and the slab is directly loaded into a heating furnace for heating, wherein the temperature of the heating furnace is 1180 ℃, and the heating and heat preserving time is 230min.
Step S3, hot rolling: the slab is subjected to hot rolling for 7 passes to obtain a hot rolled plate with the thickness of 2.2mm, and the final rolling temperature is controlled at 890 ℃ and the curling temperature is controlled at 670 ℃.
Step S4, pickling and normalizing: the hot rolled plate is normalized at 880 ℃ after shot blasting and acid washing.
Step S5, cold rolling: the above normalized plate was cold rolled to a target thickness of 0.50mm using a rough roll, and the surface roughness ra=0.82 μm after cold rolling of the strip steel.
Step S6, alkali washing: and (3) alkaline washing the cold-rolled sheet by a 70 ℃ alkaline solution tank.
Step S7, annealing: continuously annealing by a continuous annealing furnace, wherein the atmosphere in the continuous annealing furnace is mixed by hydrogen and nitrogen, H 2 40 percent of content, 950 ℃ of the soaking section temperature of the annealing furnace and 250s of annealing time.
Step S8, primary coating: after annealing the strip steel, coating the first insulating paint by a coating roller, wherein the paint is magnesium chromate paint, the magnesium chromate paint contains 10% of magnesium salt and 15% of chromate, the solid content of the paint is ensured to be 22%, and the insulating paint is cured at 500 ℃.
Step S9, secondary coating: the strip steel is subjected to air cooling and then is subjected to oil secondary painting coating after the temperature is reduced to 100 ℃, the cooling speed is 18 ℃/s, the epoxy resin content is 15%, the phenolic resin content is 8%, the aromatic amine content is 7%, the rest is an organic solvent, the solid content of the oil secondary painting is 32.5%, the strip steel is cured at 300 ℃ for 50 seconds, and the surface of the cured strip steel is shown in figure 1.
The non-oriented electrical steel manufactured by the process has the iron loss P of the finished product 1.5/50 2.70W/Kg, magnetic induction B 5000 1.69T, coating film weight 0.8g/m 2 The thickness of the coating is 4 mu m, the hardness of the coating pencil is 9H, the adhesive force of the coating is A level, and the interlayer resistance is 11000 omega mm 2 The heat resistance grade of the tablet can reach 160 ℃ multiplied by 48 hours, and the surface of the tablet has no powder falling after 160 ℃ multiplied by 48 hours aging, as shown in figure 2.
Example 2
The non-oriented silicon steel for improving the insulation property of the large generator iron core and the production method thereof specifically comprise the following steps:
step S1, continuous casting: continuously casting the molten steel refined by the RH furnace into a plate blank with the thickness of 230mm, wherein the chemical components of the plate blank are respectively as follows by weight percentage: 0.002%; si:3.0%; mn:0.30%; als:0.65%; s:0.002%, N:0.002%, ti:0.002%, and the balance of Fe and unavoidable impurity elements.
Step S2, heating: and the slab is directly loaded into a heating furnace for heating, wherein the temperature of the heating furnace is 1200 ℃, and the heating and heat preserving time is 220min.
Step S3, hot rolling: the slab is subjected to hot rolling for 7 passes to finish rolling to obtain a hot rolled plate with the thickness of 2.2mm, and the final rolling temperature is controlled to be 920 ℃ and the curling temperature is controlled to be 700 ℃.
Step S4, pickling and normalizing: the hot rolled plate is normalized at 900 ℃ after shot blasting and acid washing.
Step S5, cold rolling: the above normalized plate was cold rolled to a target thickness of 0.50mm using a rough roll, and the surface roughness ra=0.85 μm after cold rolling of the strip steel.
Step S6, alkali washing: and (3) alkaline washing the cold-rolled sheet by a 70 ℃ alkaline solution tank.
Step S7, annealing: continuous annealing by a continuous annealing furnaceThe atmosphere in the furnace is the mixture of hydrogen and nitrogen, H 2 40 percent of content, 970 ℃ of the soaking section temperature of the annealing furnace and 280s of annealing time.
Step S8, primary coating: after annealing the strip steel, coating the first insulating paint by a coating roller, wherein the paint is magnesium chromate paint, the magnesium chromate paint contains 15% of magnesium salt, 12% of chromate, the paint contains 22.5% of solid content, and the insulating paint is cured at 550 ℃.
Step S9, secondary coating: the temperature of the strip steel is reduced to 100 ℃ after air cooling, oily secondary painting is carried out, the cooling speed is 18 ℃/s, the epoxy resin content is 17%, the phenolic resin content is 10%, the aromatic amine content is 10%, the solid content of the oily secondary painting is 33%, and the oily secondary painting is solidified at 320 ℃ for 40s.
The non-oriented electrical steel manufactured by the process has the iron loss P of the finished product 1.5/50 2.60W/Kg, magnetic induction B 5000 1.68T, coating film weight 0.85g/m 2 The thickness of the coating is 4 mu m, the pencil hardness of the coating is 9H, the adhesive force of the coating is A level, and the interlayer resistance is 12000 omega mm 2 The heat resistance grade of the tablet can reach 150 ℃ multiplied by 48 hours.
Example 3
The non-oriented silicon steel for improving the insulation property of the large generator iron core and the production method thereof specifically comprise the following steps:
step S1, continuous casting: continuously casting the molten steel refined by the RH furnace into a plate blank with the thickness of 230mm, wherein the chemical components of the plate blank are respectively as follows by weight percentage: 0.002%; si:3.4%; mn:0.45%; als:1.0%; s:0.002%, N:0.002%, ti:0.002%, and the balance of Fe and unavoidable impurity elements.
Step S2, heating: and the slab is directly loaded into a heating furnace for heating, wherein the temperature of the heating furnace is 1250 ℃, and the heating and heat preserving time is 230 minutes.
Step S3, hot rolling: the slab is subjected to hot rolling for 7 passes to finish rolling to obtain a hot rolled plate with the thickness of 2.4mm, and the final rolling temperature is controlled to be 900 ℃ and the curling temperature is controlled to be 680 ℃.
Step S4, pickling and normalizing: the hot rolled plate is normalized at 870 ℃ after shot blasting and acid washing.
Step S5, cold rolling: the above normalized plate was cold rolled to a target thickness of 0.50mm using a rough roll, and the surface roughness ra=0.89 μm after cold rolling of the strip steel.
Step S6, alkali washing: and (3) alkaline washing the cold-rolled sheet by a 70 ℃ alkaline solution tank.
Step S7, annealing: continuously annealing by a continuous annealing furnace, wherein the atmosphere in the continuous annealing furnace is mixed by hydrogen and nitrogen, H 2 45% of the content, 990 ℃ of the soaking section temperature of the annealing furnace and 260s of the annealing time.
Step S8, primary coating: after annealing the strip steel, coating the first insulating paint by a coating roller, wherein the paint is magnesium chromate paint, the magnesium chromate paint contains 15% of magnesium salt, 15% of chromate, the paint contains 23% of solid, and the insulating paint is cured at 580 ℃.
Step S9, secondary coating: the temperature of the strip steel is reduced to 100 ℃ after air cooling, oily secondary painting is carried out, the cooling speed is 18 ℃/s, the epoxy resin content is 20%, the phenolic resin content is 7%, the anhydride content is 10%, the solid content of the oily secondary painting is 33.5%, and the oily secondary painting is solidified at 340 ℃ for 30s.
The non-oriented electrical steel manufactured by the process has the iron loss P of the finished product 1.5/50 2.45W/Kg, magnetic induction B 5000 1.66T, coating film weight 1.0g/m 2 The thickness of the coating is 6 mu m, the hardness of the coating pencil is 9H, the adhesive force of the coating is A level, and the interlayer resistance is 14000 omega mm 2 The heat resistance grade of the tablet can reach 150 ℃ multiplied by 48 hours.
Comparative example 1
The non-oriented silicon steel and the production method thereof specifically comprise the following steps:
step S1, continuous casting: continuously casting the molten steel refined by the RH furnace into a plate blank with the thickness of 230mm, wherein the chemical components of the plate blank are respectively as follows by weight percentage: 0.002%; si:2.8%; mn:0.15%; als:0.5%; s:0.003%, N:0.003%, ti:0.003% of Fe and the balance of unavoidable impurity elements.
Step S2, heating: and the slab is directly loaded into a heating furnace for heating, wherein the temperature of the heating furnace is 1180 ℃, and the heating and heat preserving time is 210min.
Step S3, hot rolling: the slab is subjected to hot rolling for 7 passes to obtain a hot rolled plate with the thickness of 2.2mm, and the final rolling temperature is controlled at 890 ℃ and the curling temperature is controlled at 670 ℃.
Step S4, pickling and normalizing: the hot rolled plate is normalized at 880 ℃ after shot blasting and acid washing.
Step S5, cold rolling: the above normalized plate was cold rolled to a target thickness of 0.50mm using a rough roll, and the surface roughness ra=0.30 μm after cold rolling of the strip steel.
Step S6, alkali washing: and (3) alkaline washing the cold-rolled sheet by a 70 ℃ alkaline solution tank.
Step S7, annealing: continuously annealing by a continuous annealing furnace, wherein the atmosphere in the continuous annealing furnace is mixed by hydrogen and nitrogen, H 2 40 percent of content, 950 ℃ of the soaking section temperature of the annealing furnace and 250s of annealing time.
Step S8, primary coating: after annealing the strip steel, coating the first insulating paint by a coating roller, wherein the paint is magnesium chromate paint, the magnesium chromate paint contains 10% of magnesium salt and 15% of chromate, and the insulating paint is cured at 500 ℃.
Step S9, secondary coating: the temperature of the strip steel is reduced to 100 ℃ after air cooling, oily secondary painting is carried out, the cooling speed is 18 ℃/s, the epoxy resin content is 15%, the phenolic resin content is 8%, the aromatic amine content is 7%, the solid content of the oily secondary painting is 32.5%, and the oily secondary painting is solidified at 300 ℃ for 50s.
The non-oriented electrical steel manufactured by the process has the iron loss P of the finished product 1.5/50 2.70W/Kg, magnetic induction B 5000 1.69T, coating film weight 0.7g/m 2 The thickness of the coating is 2.5 mu m, the pencil hardness of the coating is 9H, the adhesive force of the coating is B grade, and the interlayer resistance is 6000 Ω & mm 2 The heat resistance grade of each piece is 145 ℃ multiplied by 48 hours. Although the magnetic performance of the product is excellent, the adhesive force of the secondary painting coating is poor, the interlayer resistance is low, and the interlayer resistance requirement of a large-scale generator is not met.
Comparative example 2
The non-oriented silicon steel and the production method thereof specifically comprise the following steps:
step S1, continuous casting: continuously casting the molten steel refined by the RH furnace into a plate blank with the thickness of 230mm, wherein the chemical components of the plate blank are respectively as follows by weight percentage: 0.002%; si:2.4%; mn:0.30%; als:0.45%; s:0.003%, N:0.003%, ti:0.003% of Fe and the balance of unavoidable impurity elements.
Step S2, heating: the slab is directly loaded into a heating furnace for heating, the temperature of the heating furnace is 1140 ℃, and the heating and heat preserving time is 220min;
step S3, hot rolling: the plate blank is subjected to hot rolling for 7 times to finish rolling to obtain a hot rolled plate with the thickness of 2.2mm, wherein the finishing temperature is controlled at 920 ℃ and the curling temperature is controlled at 700 ℃;
step S4, pickling and normalizing: normalizing the hot rolled plate at 920 ℃ after shot blasting and acid washing;
step S5, cold rolling: the normalizing plate is cold rolled to the target thickness of 0.50mm by adopting a rough roll, and the surface roughness Ra=0.85 mu m after the cold rolling of the strip steel;
step S6, alkali washing: washing the cold-rolled sheet with alkali in a 70 ℃ alkali liquor tank;
step S7, annealing: continuously annealing by a continuous annealing furnace, wherein the atmosphere in the continuous annealing furnace is mixed by hydrogen and nitrogen, H 2 40% of the content of the aluminum alloy, 930 ℃ of the soaking section of the annealing furnace and 280s of the annealing time.
Step S8, primary coating: after annealing the strip steel, coating the first insulating paint by a coating roller, wherein the paint is magnesium chromate paint, the magnesium chromate paint contains 10% of magnesium salt and 15% of chromate, and the insulating paint is cured at 500 ℃.
Step S9, secondary coating: the temperature of the strip steel is reduced to 100 ℃ after air cooling, oily secondary painting is carried out, the cooling speed is 25 ℃/s, the epoxy resin content is 15%, the phenolic resin content is 8%, the aromatic amine content is 7%, the rest is organic solvent, the solid content of the oily secondary painting is 32.5%, and the solidifying time is 40s after 320 ℃.
The non-oriented electrical steel manufactured by the process has the iron loss P of the finished product 1.5/50 2.85W/Kg, magnetic induction B 5000 1.71T, coating film weight 0.85g/m 2 The thickness of the coating is 4 mu m, the pencil hardness of the coating is 9H, the adhesive force of the coating is A level, and the interlayer resistance is 12000 omega mm 2 The heat resistance grade of the tablet is 150 ℃ multiplied by 48 hours. Although the secondary painting performance of the product is better, the magnetic performance of the product is poorer, and the requirement of a large-sized generator on low iron loss of the magnetic performance is not met.
Comparative example 3
The non-oriented silicon steel and the production method thereof specifically comprise the following steps:
step S1, continuous casting: continuously casting the molten steel refined by the RH furnace into a plate blank with the thickness of 230mm, wherein the chemical components of the plate blank are respectively as follows by weight percentage: 0.002%; si:3.0%; mn:0.30%; als:0.65%; s:0.002%, N:0.002%, ti:0.002%, and the balance of Fe and unavoidable impurity elements.
Step S2, heating: and the slab is directly loaded into a heating furnace for heating, wherein the temperature of the heating furnace is 1200 ℃, and the heating and heat preserving time is 220min.
Step S3, hot rolling: the slab is subjected to hot rolling for 7 passes to finish rolling to obtain a hot rolled plate with the thickness of 2.2mm, and the final rolling temperature is controlled to be 920 ℃ and the curling temperature is controlled to be 700 ℃.
Step S4, pickling and normalizing: the hot rolled plate is normalized at 900 ℃ after shot blasting and acid washing.
Step S5, cold rolling: the above normalized plate was cold rolled to a target thickness of 0.50mm using a rough roll, and the surface roughness ra=0.85 μm after cold rolling of the strip steel.
Step S6, alkali washing: and (3) alkaline washing the cold-rolled sheet by a 70 ℃ alkaline solution tank.
Step S7, annealing: continuously annealing by a continuous annealing furnace, wherein the atmosphere in the continuous annealing furnace is mixed by hydrogen and nitrogen, H 2 The content is 40%. The soaking section temperature of the annealing furnace is 970 ℃, and the annealing time is 280s.
Step S8, primary coating: after annealing the strip steel, coating the first insulating paint by a coating roller, wherein the paint is magnesium chromate paint, the magnesium chromate paint contains 15% of magnesium salt, 15% of chromate, the paint contains 23% of solid, and the insulating paint is cured at 550 ℃.
8) The temperature of the strip steel is reduced to 100 ℃ after air cooling, oily secondary painting coating is carried out, the cooling speed is 18 ℃/s, the epoxy resin content is 27%, the phenolic resin content is 10%, the aromatic amine or anhydride content is 7%, and the curing time is 60s after 370 ℃.
The non-oriented electrical steel manufactured by the process has the iron loss P of the finished product 1.5/50 2.60W/Kg, magnetic induction B 5000 1.68T, coating film weight 0.85g/m 2 The thickness of the coating layer was 4 μm,the hardness of the coating pencil is 9H, the adhesion of the coating is B grade, and the interlayer resistance is 12000 Ω & mm 2 The heat resistance grade of the tablet is 140 ℃ multiplied by 48 hours. Although the magnetic properties of the product are better, the secondary painting of the product is resistant to heat, over-burning occurs, the surface yellowing is serious, as shown in figure 3, the heat-resistant grade is lower, and the surface coating is peeled off when the heat-resistant grade is only 140 ℃ multiplied by 48h and 145 ℃ multiplied by 48h, as shown in figure 4.
Comparative example 4
The non-oriented silicon steel and the production method thereof specifically comprise the following steps:
step S1, continuous casting: continuously casting the molten steel refined by the RH furnace into a plate blank with the thickness of 230mm, wherein the chemical components of the plate blank are respectively as follows by weight percentage: 0.003%; si:2.80%; mn:0.15%; als:0.50%; s:0.003%, N:0.003%, ti:0.003% of Fe and the balance of unavoidable impurity elements.
Step S2, heating: and the slab is directly loaded into a heating furnace for heating, wherein the temperature of the heating furnace is 1180 ℃, and the heating and heat preserving time is 230min.
Step S3, hot rolling: the slab is subjected to hot rolling for 7 passes to obtain a hot rolled plate with the thickness of 2.2mm, and the final rolling temperature is controlled at 890 ℃ and the curling temperature is controlled at 670 ℃.
Step S4, pickling and normalizing: the hot rolled plate is normalized at 880 ℃ after shot blasting and acid washing.
Step S5, cold rolling: the above normalized sheet was cold rolled to a target thickness of 0.50mm.
Step S6, alkali washing: and (3) alkaline washing the cold-rolled sheet by a 70 ℃ alkaline solution tank.
Step S7, annealing: continuously annealing by a continuous annealing furnace, wherein the atmosphere in the continuous annealing furnace is mixed by hydrogen and nitrogen, H 2 40 percent of content, 950 ℃ of the soaking section temperature of the annealing furnace and 250s of annealing time.
And S8, coating an insulating coating by a coating roller after annealing the strip steel, wherein the coating is magnesium chromate coating, the magnesium chromate coating contains 15% of magnesium salt, 15% of chromate, the coating solid content is 23%, and curing the insulating coating at 500 ℃.
The non-oriented electrical steel manufactured by the process has the iron loss P of the finished product 1.5/50 2.70W/Kg, magnetic induction B 5000 The temperature of the mixture was set to 1.69T,the coating film weight was 0.4g/m 2 The thickness of the coating is 0.7 mu m, and the adhesive force of the coating is A grade but the interlayer resistance is 200Ω.mm 2 And/or the sheet can not meet the requirement of a large motor on the interlayer resistance of a silicon steel surface coating.

Claims (10)

1. A production method of unoriented silicon steel for improving the insulation property of a large-sized generator iron core is characterized in that the surface of a strip steel coated with insulating paint at one time is coated with oily secondary paint, and the strip steel coated with the insulating paint at one time has the surface roughness Ra of more than 0.8 mu m after the oily secondary paint is cured at 300-350 ℃.
2. The method for producing non-oriented silicon steel for improving the insulation property of a large-sized generator iron core according to claim 1, wherein the oily secondary painting coating comprises 15-25% of film forming agent, 5-15% of curing agent and 5-15% of additive in percentage by mass, and the balance of organic solvent, wherein the solid content of the oily secondary painting is more than or equal to 30%.
3. The method for producing non-oriented silicon steel for improving insulation of a large-sized generator core according to claim 2, wherein the film forming agent is epoxy resin, the curing agent is aromatic amine or acid anhydride, and the additive is phenolic resin.
4. The method for producing non-oriented silicon steel for improving insulation of large-scale generator iron core according to claim 3, wherein the magnesium-based chromate insulating coating comprises magnesium salt, chromate, latex resin solution and surfactant, wherein the magnesium salt content is 10% -20%, the chromate content is 10% -20%, the other component system is 30% -80%, and the solid content of the coating is more than or equal to 20%.
5. The method for producing non-oriented silicon steel for improving insulation of large-sized generator iron core according to claim 4, wherein the chemical composition of the slab comprises c.ltoreq.0.003% by weight, si:2.8 to 3.4 percent, mn:0.15 to 0.45 percent, als:0.5 to 1.0 percent, S is less than or equal to 0.003 percent, N is less than or equal to 0.003 percent, ti is less than or equal to 0.003 percent, and the balance is Fe and unavoidable impurities.
6. The method for producing non-oriented silicon steel for improving insulation of a large-sized generator core according to claim 5, comprising the steps of:
step S1, continuous casting: continuously casting molten steel into a plate blank;
step S2, heating: the slab is directly loaded into a heating furnace for heating, the temperature of the heating furnace is controlled to 1150-1250 ℃, and the total heating time is 210-230 min;
step S3, hot rolling: finish rolling the slab to a hot rolled plate with the thickness of 2.2-2.6 mm, wherein the finish rolling temperature is 860-920 ℃, and the coiling temperature is 650-700 ℃;
step S4, pickling and normalizing: normalizing the hot rolled plate after shot blasting and acid washing at 850-900 ℃;
step S5, cold rolling: the normalized sheet is cold-rolled to the target thickness of 0.50mm, the surface roughness Ra of the cold-rolled strip steel is more than 0.8 mu m,
step S6, alkali washing: continuously annealing the cold-rolled sheet, passing the strip steel through an alkali liquor tank at 70-80 ℃ before annealing,
step S7, annealing: the atmosphere in the continuous annealing furnace adopts dry atmosphere, the temperature of the soaking section of the annealing furnace is 950-1000 ℃, and the annealing time is 240-480 s;
step S8, primary coating: after annealing the strip steel, carrying out primary coating of magnesium chromate insulating paint through a coating roller, curing the insulating paint at 500-600 ℃, and cooling by air cooling after curing;
step S9, secondary coating: the strip steel is reduced to 100-200 ℃ and then is coated by oil-based secondary painting, and after the oil-based secondary painting is coated, the strip steel is cured at 300-350 ℃ for 30-50 s.
7. The method for producing non-oriented silicon steel for improving insulation of large-scale generator core as defined in claim 6, wherein the continuous annealing furnace atmosphere in step S7 is a mixture of hydrogen and nitrogen, H 2 And N 2 The ratio of (2) is 3:7.
8. The method for producing non-oriented silicon steel for improving the insulation property of a large-sized generator iron core according to claim 7, wherein the solidifying temperature in the step S8 is 500-600 ℃, and the cooling speed of the strip steel is less than or equal to 20 ℃/S by adopting air cooling after solidification.
9. The non-oriented silicon steel produced by the production method as claimed in any one of claims 1 to 8, characterized in that the inter-coating layer resistance of the non-oriented silicon steel is > 10000 Ω -mm 2 The heat resistance of the tablet reaches 155 ℃ multiplied by 48 hours (grade F), and the weight of the film is 0.8 to 1.0g/m 2 The thickness of the coating is 3-6 mu m, the pencil hardness of the coating is more than 9H, and the adhesive force of the coating is A grade.
10. The non-oriented silicon steel according to claim 8, wherein the magnetic properties of the non-oriented silicon steel satisfy the iron loss P 1.5/50 Less than or equal to 3.0W/Kg and magnetic induction B 50 ≥1.66T。
CN202310806855.2A 2023-06-30 2023-06-30 Production method of unoriented silicon steel for improving insulation of large-sized generator iron core and product prepared by production method Pending CN117000562A (en)

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