阅读说明：本技术 适用于无底层的含Bi超高磁感取向硅钢的无铬半有机绝缘涂料 (Chromium-free semi-organic insulating paint suitable for Bi-containing ultrahigh magnetic induction oriented silicon steel without bottom layer ) 是由 刘婷 胡守天 杨佳欣 刘敏 宋刚 赵胜利 陈博 于 2020-06-15 设计创作，主要内容包括：本发明公开了一种适用于无底层的含Bi超高磁感取向硅钢的无铬半有机绝缘涂料,所述无铬半有机绝缘涂料的原料按重量百分比计包括15～25％的磷酸盐水溶液、1～15％的胶体二氧化硅或胶状三氧化二铝或二氧化钛、30～60％的有机树脂和0.5～5％的金属氧化物,余量为水；其中,所述磷酸盐水溶液中,磷酸盐含量为33％,且阳离子为Mg、Al、Ca、Zn和Na中任意一种或多种；所述金属氧化物中,金属阳离子为Mn、Co、Ni、Al、Ca和Na中任意一种或几种。本发明的涂料涂覆后,经300℃-500℃烘干,钢板表层树脂偏聚,绝缘膜不会被破坏,涂层焊接性能良好,焊接速度为80-120cm/min时,焊缝处不产生气泡,无气孔。(The invention discloses a chromium-free semi-organic insulating coating suitable for Bi-free ultrahigh-magnetic-induction oriented silicon steel, which comprises the following raw materials, by weight, 15-25% of a phosphate aqueous solution, 1-15% of colloidal silicon dioxide or colloidal aluminum oxide or titanium dioxide, 30-60% of organic resin, 0.5-5% of metal oxide and the balance of water; wherein, in the phosphate aqueous solution, the phosphate content is 33%, and the cation is any one or more of Mg, Al, Ca, Zn and Na; in the metal oxide, the metal cation is any one or more of Mn, Co, Ni, Al, Ca and Na. After the coating is coated, the coating is dried at 300-500 ℃, the resin on the surface layer of the steel plate is polymerized, the insulating film cannot be damaged, the welding performance of the coating is good, and when the welding speed is 80-120cm/min, no bubbles are generated at the welding seam and no air holes exist.)

1. A chromium-free semi-organic insulating paint suitable for Bi-containing ultrahigh magnetic induction oriented silicon steel without a bottom layer is characterized in that: the raw materials of the chromium-free semi-organic insulating coating comprise, by weight, 15-25% of a phosphate aqueous solution, 1-15% of colloidal silicon dioxide or colloidal aluminum oxide or titanium dioxide, 30-60% of an organic resin, 0.5-5% of a metal oxide and the balance of water; wherein, in the phosphate aqueous solution, the phosphate content is 33%, and the cation is any one or more of Mg, Al, Ca, Zn and Na; in the metal oxide, the metal cation is any one or more of Mn, Co, Ni, Al, Ca and Na.

2. The non-chrome semi-organic insulating paint for the Bi-containing ultra-high magnetic induction oriented silicon steel without the primer layer as claimed in claim 1, wherein: the raw materials of the chromium-free semi-organic insulating coating comprise, by weight, 19-23% of a phosphate aqueous solution, 5-10% of colloidal silicon dioxide or colloidal aluminum oxide or titanium dioxide, 45-55% of an organic resin, 1.5-3.5% of a metal oxide and the balance of water; wherein, in the metal oxide, the metal cation is any one or more of Al, Ca and Na.

3. The non-chrome semi-organic insulating paint for the Bi-containing ultra-high magnetic induction oriented silicon steel without the primer layer as claimed in claim 1, wherein: the particle size of the colloidal silicon dioxide or colloidal aluminum oxide or titanium dioxide is 0.05-0.07 mu m.

4. The non-chrome semi-organic insulating paint for the Bi-containing ultra-high magnetic induction oriented silicon steel without the primer layer as claimed in claim 1, wherein: the organic resin is one or more of polyamide-imide organic resin, epoxy resin, propylene resin and amino resin

5. The non-chrome semi-organic insulating paint for the Bi-containing ultra-high magnetic induction oriented silicon steel without the primer layer as claimed in claim 1, wherein: the size of the organic resin is 1-35 μm.

6. The non-chrome semi-organic insulating paint for the Bi-containing ultra-high magnetic induction oriented silicon steel without the primer layer as claimed in claim 1, wherein: the raw materials of the chromium-free semi-organic insulating paint comprise, by weight, 22% of magnesium phosphate aqueous solution, 8% of colloidal silicon dioxide, 50% of propylene resin and 2.5% of aluminum oxide.

7. The use of the chromium-free semi-organic insulating coating of claim 1 for protecting a primer-free ultrahigh magnetic induction oriented silicon steel; the chemical components of the bottom-layer-free ultrahigh-magnetic-induction oriented silicon steel comprise, by mass, 0.04-0.08% of C, 3.14-3.4% of Si, 0.06-0.12% of Mn, 0.02-0.03% of S, Als: 0.02% -0.03%, N: 0.006% -0.01%, Bi: 0.0001 to 0.1 percent; the balance of Fe and inevitable impurities; the method is characterized in that: the application method comprises the following steps: and (2) carrying out decarburization annealing after cold rolling of the hot rolled plate, coating an annealing separant, carrying out high-temperature annealing, removing the separant on the surface of the substrate, carrying out leveling stretching annealing, coating the chromium-free semi-organic insulating coating on the surface of the steel plate, and drying at the temperature of 300-500 ℃ to obtain a coating with the thickness of 2-10 microns.

Technical Field

The invention relates to the field of insulating paint, in particular to a chromium-free semi-organic insulating paint suitable for Bi-containing ultrahigh magnetic induction oriented silicon steel without a bottom layer.

Background

Oriented silicon steel is widely used as a magnetic iron core material, and is mainly used for manufacturing iron cores of transformers and large motors in the power transmission and transformation industry. In recent years, because social requirements on energy conservation and environmental protection are increasingly urgent, the requirements on reducing the iron loss and improving the magnetization characteristic of the oriented silicon steel are stronger, and further improvement of the magnetic induction intensity is urgently required in the design of motors and transformers, which is beneficial to saving the cost of electric appliances and reducing the noise.

The existing method for manufacturing the oriented silicon steel is to coat a layer of annealing separant on the surface of the silicon steel in order to prevent the silicon steel coil from being bonded in the high-temperature annealing process. In the high-temperature annealing process, magnesium oxide and a silicon dioxide film on the surface of silicon steel are subjected to chemical reaction to generate a magnesium silicate film, and the magnesium silicate film has certain insulating and antirust capabilities and is generally called a magnesium silicate bottom layer. In order to further improve the insulation, corrosion resistance, heat resistance, magnetic properties, etc. of the steel sheet, a stress insulation coating layer is further applied to the surface. The excellent insulating coating has smooth and flat surface, good adhesive force, good insulating property, corrosion resistance and weldability. The stress insulation coating T-2 coating used at present can meet the performance requirements of common or high magnetic induction oriented silicon steel.

In order to further improve the magnetic flux density of the oriented silicon steel, a technology of adding Bi to a base material of the oriented silicon steel is proposed. The action of Bi is believed to promote the fine precipitation of MnS, AlN, or the like as an inhibitor, thereby improving the strength of the inhibitor, and to contribute to the selective growth of (110) [001] oriented grains, thereby improving the magnetic properties of the oriented silicon steel. However, when Bi is added, in the course of the secondary recrystallization temperature, [% Bi ] in the steel is vaporized and diffused from the surface of the steel sheet. And a bottom layer (liquid state) is generated on the surface of the steel plate in the process of secondary recrystallization temperature, and then Bi gas is accumulated on the interface of the bottom layer/the surface of the steel plate. If the steel sheet is stacked in a thickness of a micron, the primer layer is peeled off from the surface of the steel sheet. Therefore, after the Bi is added, the bottom layer of the oriented silicon steel can fall off from the surface of the steel plate, and the bottom layer can be removed after the steel plate is pickled, so that the oriented silicon steel without the bottom layer is formed. If the conventional T-2 stress coating is directly coated, the coating is easy to fall off and has poor adhesion. Therefore, for producing the Bi-containing ultrahigh magnetic induction oriented silicon steel, the problem of insulating coating coated on the surface of the Bi-containing ultrahigh magnetic induction oriented silicon steel seriously restricts the production and application of the product.

Because the non-bottom oriented silicon steel has the excellent magnetic property of the oriented silicon steel and the excellent processing property of the non-oriented silicon steel, the non-bottom oriented silicon steel has wide application prospect and is the development direction of the oriented silicon steel. In recent years, the non-bottom layer oriented silicon steel has been applied to the field of large-scale rotating electrical machines, but generally speaking, the non-bottom layer oriented silicon steel is still in the stages of research and development and small-scale production, and the coating technology is an important problem for restricting the development of the non-bottom layer oriented silicon steel.

Chinese patent publication No. CN104928567A discloses a grain-oriented silicon steel with good processability and a method for manufacturing the same. The surface of the steel plate with the bottom layer of the glass film removed is coated with a semi-organic chromium-free insulating coating, and the effective components of the chromium-free semi-organic coating are phosphate and organic resin. After coating, the steel plate is baked to form a film at the plate temperature of 200-450 ℃, so that a surface tension coating with high hardness and poor adhesion cannot be formed on the surface of the substrate, and the steel plate has good processing performance. The method only considers the punching performance of the coating and does not consider the welding performance of the coating. The weldability of the coating and the performance of the punching sheet are mutually contradictory. And the organic resin of the coating is epoxy resin or amino resin, which is beneficial to the punching performance of the coating, but the weldability is low.

Chinese patent publication No. CN1978569A discloses a high temperature resistant organosilicon material such as polyether modified silicone oil added to a coating, which can perform a similar function to that of organic resin, has good surface quality after coating, can withstand high temperature sintering without thermal decomposition, and improves the punching performance of oriented silicon steel sheets. However, the coating is applied based on a substrate having a good glass film bottom layer, and chromic anhydride in the coating liquid is a toxic and harmful substance, which has been definitely prohibited from being used by the ROHS directive.

KR20010082119 discloses a chromium-free oriented electrical steel and the development of its insulating coating, introduces the chemical composition and production process of the steel, and its final insulating coating comprises: zinc phosphate; magnesium phosphate; 0.5-12% of boric acid or borate containing Na, Al, Ca, Li and Mg. The results of the coating showed poor corrosion resistance and poor appearance of the coating.

Patent No. JP19790150688 discloses an insulating coating for chromium-free oriented silicon steel, the content of which comprises: 7-60 parts of magnesium phosphate; 8-40 parts of one or two sulfates; 20 parts of silica gel. The results of the coating show that the coating has a general adhesion and a poor appearance, while the corrosion resistance of the coating becomes unsatisfactory. Patent No. ZL200610030717.6 proposes a chromium-free environment-friendly insulating coating for oriented silicon steel. The chemical components by mass percent are as follows: 0.01 to 3 percent of block polyether nonionic surfactant, 0.2 to 3 percent of boric acid, 9 to 30 percent of aluminum dihydrogen phosphate and 8 to 20 percent of colloidal silicon dioxide. The coating results show that the coating is not resistant to high temperature, resulting in poor corrosion resistance. Application No. JP20070176395 discloses a chromium-free stress coating liquid for grain-oriented electrical steel sheet having excellent moisture absorption and iron loss reducing effect. The coating liquid comprises the following components: 20 parts by mass of silica gel, 10-80 parts by mass of one or more phosphates selected from Mg, Al, Ca, Fe and Mn, 3-30 parts by mass of chlorides selected from magnesium, aluminum, iron, manganese, cobalt, bismuth, zinc, calcium, barium, strontium or nickel, and 1-10 parts by mass of one or more borates and sulfates selected from Li, Na, K, Mg, Mn, Ca, Ba, Sr, Fe, Co, Sn, Ni, Cu, Zn, Al and Bi. However, the heat resistance of the coating film is poor. Patent No. ZL201310673461.0 discloses a chromium-free stress coating capable of improving the surface tension of oriented silicon steel and a preparation method thereof, which helps the coating to provide the steel plate tension from the components of the coating liquid.

Although the formulas can better meet certain performance of the steel plate after coating by the coating solution, the problems of poor bottom layer and easy falling of the substrate are not considered, and the formulas are not suitable for the bottom-layer-free ultrahigh magnetic induction oriented silicon steel containing Bi.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides the chromium-free semi-organic insulating paint which is suitable for the Bi-containing ultrahigh magnetic induction oriented silicon steel without a bottom layer, the chromium-free semi-organic insulating paint is coated on the surface of a steel plate, and after the steel plate is dried at the temperature of 500 ℃, the surface quality of the steel plate is excellent, the coating is not easy to fall off, and the chromium-free semi-organic insulating paint has good adhesiveness, insulativity and welding performance. The coated Bi-containing ultrahigh magnetic induction bottom-layer-free oriented silicon steel can replace non-oriented silicon steel to be used in a motor, and has the characteristics of excellent magnetism of the oriented silicon steel on one hand and excellent non-oriented processability on the other hand.

In order to achieve the purpose, the invention designs a chromium-free semi-organic insulating paint suitable for Bi-free ultrahigh-magnetic-induction oriented silicon steel, which comprises 15-25 wt% of phosphate aqueous solution, 1-15 wt% of colloidal silicon dioxide or colloidal aluminum oxide or titanium dioxide, 30-60 wt% of organic resin, 0.5-5 wt% of metal oxide and the balance of water; wherein, in the phosphate aqueous solution, the phosphate content is 33%, and the cation is any one or more of Mg, Al, Ca, Zn and Na; in the metal oxide, the metal cation is any one or more of Mn, Co, Ni, Al, Ca and Na.

Further, the raw materials of the chromium-free semi-organic insulating coating comprise, by weight, 19-23% of a phosphate aqueous solution, 5-10% of colloidal silicon dioxide or colloidal aluminum oxide or titanium dioxide, 45-55% of an organic resin, 1.5-3.5% of a metal oxide, and the balance of water; wherein, in the metal oxide, the metal cation is any one or more of Al, Ca and Na.

And further, the particle size of the colloidal silicon dioxide or colloidal aluminum oxide or titanium dioxide is 0.05-0.07 mu m.

Still further, the organic resin is one or more of polyamide-imide organic resin, epoxy resin, acrylic resin and amino resin

Still further, the size of the organic resin is 1 to 35 μm.

Still further, the raw materials of the chromium-free semi-organic insulating paint comprise 22 percent of magnesium phosphate aqueous solution, 8 percent of colloidal silica, 50 percent of propylene resin and 2.5 percent of alumina according to weight percentage.

The invention also provides an application of the chromium-free semi-organic insulating coating in protecting the bottom-layer-free ultrahigh magnetic induction oriented silicon steel; the chemical components of the bottom-layer-free ultrahigh-magnetic-induction oriented silicon steel comprise, by mass, 0.04-0.08% of C, 3.14-3.4% of Si, 0.06-0.12% of Mn, 0.02-0.03% of S, Als: 0.02% -0.03%, N: 0.006% -0.01%, Bi: 0.0001 to 0.1 percent; the balance of Fe and inevitable impurities; the application method comprises the following steps: and (2) carrying out decarburization annealing after cold rolling of the hot rolled plate, coating an annealing separant, carrying out high-temperature annealing, removing the separant on the surface of the substrate, carrying out leveling stretching annealing, coating the chromium-free semi-organic insulating coating on the surface of the steel plate, and drying at the temperature of 300-500 ℃ to obtain a coating with the thickness of 2-10 microns.

Various material principles of the invention:

1. the inorganic component is mainly phosphate aqueous solution, and is selected from 1 or more than 2 of inorganic compounds of Mg, Al, Ca, Zn, Na, etc., and the dosage of the inorganic component accounts for 15-25% of the total mass of the coating liquid. The content of phosphate is not too high, so that the situation that the surface of the coating is corroded when the coating is sintered due to more free phosphoric acid in the coating, the appearance of the coating is not good, and the welding performance is also reduced is prevented. The phosphate content must not be too low, and because the surface of the substrate of the Bi-added steel is rough, the phosphate does not have enough lubrication effect on the surface, and the appearance of the coating is affected.

2. Adding colloidal silicon dioxide or colloidal aluminum oxide or titanium dioxide with the particle size of 0.05-0.07 mu m into the insulating coating liquid, wherein the using amount of the colloidal silicon dioxide or colloidal aluminum oxide or titanium dioxide accounts for 1-15% of the total mass of the coating liquid. The content of the coating is not too high, otherwise, the colloidal silicon dioxide or colloidal aluminum oxide or titanium dioxide is not well soluble with resin, the coating is not stable, patterns are easily generated on the surface of the coating after sintering, and dust is easily generated during punching. The content can not be too low, the heat resistance of the semi-organic coating can be improved due to the addition of colloidal silicon dioxide or colloidal aluminum oxide or titanium dioxide, meanwhile, after the addition of the colloidal silicon dioxide or colloidal aluminum oxide or titanium dioxide, small convex areas can be easily generated on the surface of the coating after sintering due to the uniformly dispersed coarse particles in the coating liquid due to the rough surface of the oriented silicon steel plate substrate added with Bi, and the coating can be used as a channel for gas generated by welding, so that the welding performance of the coating can be improved.

3. Adding compounds of Mn, Co, Ni, Al, Ca, Na and the like, wherein the dosage of the compounds accounts for 0.5-5% of the total mass of the coating liquid. On one hand, the coating can neutralize redundant free acid, inhibit moisture absorption after the coating is sintered, and prevent the steel plate from being bonded when stamped. On the other hand, because the surface of the substrate of the oriented silicon steel plate added with Bi is rough, and compounds of Mn, Co, Ni, Al, Ca, Na and the like and free acid are neutralized, an insulating film which is difficult to dissolve in water is formed on the surface of the oriented silicon steel substrate without the bottom layer, the weldability of the coating can be improved, and the appearance of the coating is good.

4. The organic resin is one or more of polyamide-imide organic resin, epoxy resin, acrylic resin and amino resin. Because the surface of the oriented silicon steel plate added with Bi has no bottom layer, the combination of the coating and the base material depends on the chemical bond energy of the molecules of the organic high molecular material to permeate the gaps of the base layer so as to ensure the physical adhesion of the coating and the substrate, thereby ensuring the adhesiveness and the insulativity of the coating. The total resin content in the insulating coating liquid is 30-60%. The resin content is more than 30%, which is beneficial to improving the welding performance of the coating. However, when the content is too high, the generated gas does not escape in time when the organic matter is thermally decomposed, and remains in the weld zone to form pores, which leads to a decrease in weldability of the coating. The resin content is too low, so that the coating has poor adhesion and is easy to fall off.

a. The polyamide-imide organic resin has a high thermal decomposition peak temperature (544 ℃), has a high residual carbon content of 36% at 1000 ℃, and therefore generates few pores during welding and has good welding performance.

b. The glass transition temperature of the epoxy resin, the acrylic resin and the amino resin is 30-150 ℃, and the resin has high solvent resistance and is favorable for the good adhesion of an insulating film formed on the surface of the Bi-containing oriented silicon steel.

The organic resin has the particle size of 1-35 mu m, the particle size is too small, the temperature resistance of the coating is poor, and pores are easy to generate during welding. The particle size is too large, resulting in a rough coating surface.

The invention has the beneficial effects that:

1. the environment-friendly insulating coating liquid provided by the invention aims at the Bi-added bottom-layer-free ultrahigh magnetic induction oriented silicon steel, the product can be used in a motor instead of non-oriented silicon steel, and the product has good magnetic property of the oriented silicon steel and good processing property of the non-oriented silicon steel. Because the surface of the Bi-added ultrahigh magnetic induction oriented silicon steel is not easy to form a bottom layer, the coating is easy to fall off after being coated with the conventional inorganic coating liquid, and the adhesion of the coating is poor. After the semi-organic environment-friendly insulating paint provided by the invention is used, the surface coating has good adhesiveness and excellent insulating property and welding performance, and the coating liquid does not contain chromium elements harmful to the environment and human bodies.

2. After the coating is coated and dried at 300-500 ℃, the resin on the surface layer of the steel plate is polymerized eccentrically, an insulating film cannot be damaged, the welding performance of the coating is good, and when the welding speed is 80-120cm/min, no bubbles are generated at a welding seam and no air holes exist.

Detailed Description

The present invention is described in further detail below with reference to specific examples so as to be understood by those skilled in the art.