JPH03232976A - Production of nonoriented silicon steel sheet excellent in film characteristic after stress relief annealing and total organic surface treating agent therefor - Google Patents

Abstract

PURPOSE:To improve the weldability of an organic resin film and the sliding characteristic and electric insulating property of a steel sheet after annealing by adding and mixing a specific heat resisting coarse-grained resin into a base resin. CONSTITUTION:In a method for producing a nonoriented silicon steel sheet, as a surface treating agent for forming organic film, one or >=2 kinds among the grains of methyl methacrylate, polyacrylonitrile, polystyrene, sulfonated styrene, cellulose, silicone, melamine, phenol, polyvinyl alcohol and/or copolymers and crosslinked matters thereof in which grain size is regulated to 1-100mum are incorporated by 2-30 pts.wt. based on 100 pts.wt. of one or >=2 kinds among acryl, styrene, epoxy, vinyl acetate, polyvinyl alcohol resin and/or copolymers thereof. This surface treating agent is applied to a steel sheet after final finish annealing, followed by baking treatment.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a non-directional steel sheet with excellent punching properties, weldability after lamination, heat resistance in strain relief annealing, slipperiness of steel sheets after annealing, and electrical insulation properties. The present invention relates to a method for producing a magnetic electrical steel sheet and an all-organic surface treatment agent therefor.

(Prior Art) In order to reduce iron loss due to eddy currents, electrical steel sheets are used after being coated with an insulating film on the surface and subjected to baking treatment. The iron core of a motor or transformer that uses electromagnetic steel sheets is made by slitting the electromagnetic steel sheets or strips to a predetermined width, then continuously punching or cutting them into the shape of the iron core, then stacking them and welding the edges. Alternatively, after fixing with caulking, strain relief annealing is performed at a temperature range of 700 to 800° C. if necessary, and then the wire is wound and then inserted into a case to produce the final product. Therefore, the insulation coating on electrical steel sheets is required to have properties such as not only high insulation resistance but also excellent adhesion, punchability, heat resistance, oil resistance, and not reducing the space factor when the steel sheets are laminated. . In addition, as a special case, trans river iron core or EI
When there is a re-lamination process after annealing, as in cocoa, the slipperiness of the steel plate after annealing affects the work efficiency in the re-lamination process, so the film is also required to have good slipperiness.

Many methods for forming an insulating film have been proposed in order to provide these properties to the electromagnetic steel sheet film. These are: 1) those that use an entirely inorganic surface treatment agent whose main component is phosphate or chromic acid, and 2) a semi-organic surface treatment agent that is based on chromate and contains an organic resin. and 3) those that use a surface treatment agent that is entirely organic, consisting entirely of organic substances.

In the case of 1) film formation method using a surface treatment agent based on all inorganic components, although the heat resistance of the film and the weldability of the steel plate laminate (iron core) edge part are good, the punching property of the steel plate,
There is a problem of poor adhesion.

On the other hand, when using the film forming method using an all-organic surface treatment agent in 3), the punching properties and adhesion of the steel sheet are excellent, but the heat resistance of the film and the edges of the steel sheet laminate (iron core) are excellent. There is a problem of poor weldability.

In order to compensate for these two drawbacks, 2) a film forming method using a semi-organic surface treatment agent has been proposed.

Furthermore, recently, many improvements to the above-mentioned various film forming methods have been proposed.

Japanese Patent Publication No. 49-19078 discloses roughening the surface of an electromagnetic steel sheet that has been punched or cut into a predetermined shape as a means for improving the weldability of the sheet.

That is, (a) a method in which a roll having a rough surface is brought into contact with the unhardened layer of a steel sheet that is being coated with an organic film and is being baked, to form a rough surface on the film, and (ii) a method in which a coating roll with grooves carved therein is used. A film with vertical grooves is formed on the surface of the steel plate, and then a steel roll with grooves extending in the axial direction is brought into contact with the unhardened layer during baking to form grooves extending in the width direction of the steel plate to roughen it. c) Approximately 2
The above-mentioned publication discloses a method of adding organic particles having a diameter of .mu.m or more, applying the mixture to a steel plate, and baking it.

On the other hand, JP-A No. 49-107035 proposes a composition comprising polyvinyl alcohol and a styrene emulsion/acrylic resin as an organic coating composition for electrical steel sheets. This is due to the advantages of the three resins mentioned above, namely, uniform film forming properties, high adhesion, and oil resistance of polyvinyl alcohol, heat resistance of styrene emulsion resin, solvent resistance of water-soluble acrylic resin, and It effectively utilizes the thermal softening prevention properties of the resins and complements the shortcomings of each resin.

In addition, Japanese Patent Publication No. 55-21111 discloses that as a means to improve the dispersibility of organic particles and their adhesion to steel sheets,
By adding organic particles to the coating agent when mixing one or two of the phosphoric acid-based to chromic acid-based materials with an organic resin on the surface of an electrical steel sheet, a surface roughness of 2 to 10 μm (H,,,X) can be achieved. A method for obtaining an electrical steel sheet having an electrically insulating film with excellent punchability and weldability is disclosed. That is, organic particles with a diameter of 5 μm are added in advance to an emulsion resin solution and dispersed uniformly, and then this solution is mixed with an inorganic solution consisting of one or two types of phosphoric acid to chromic acid. 400-700 after applying to the surface of the electromagnetic steel sheet
By performing a short-time baking treatment in a temperature range of .degree. C., the resin is partially melted and its adhesion is improved.

As a means to improve annealing resistance, it was proposed in Japanese Patent Publication No. 1983-1973 to apply a treatment solution containing a mixture of phosphoric acid, chromic acid, boric acid, a water-soluble organic compound having a thio bond, and Meishun to electrical steel sheets.
It is disclosed in Japanese Patent No. 1348.

According to this prior art, although the electrical insulation properties of the annealed electrical steel sheet are considerably improved, the punchability is not sufficient.

As described above, the main focus of conventional organic or semi-organic insulating films is to suppress the deterioration of weldability due to gases generated from organic substances, and for this purpose, in order to improve the air permeability between steel plates, Efforts have been made to increase film surface roughness.

However, in conventional organic or semi-organic insulation coatings, the heat resistance of the organic material is at most 400 to 500''C.
When a magnetic steel sheet is subjected to high-temperature heat treatment in a temperature range of ~800''C, the organic matter is burned away and the properties required of the film, such as insulation, corrosion resistance, and slipperiness of the steel sheet, are lost.

In this way, electrical steel sheets with conventional organic coatings have excellent punching workability and adhesion, but when heat treatments such as stress relief annealing are applied to electrical steel sheets, the properties of the coating deteriorate significantly. It had a fundamental problem. In an attempt to solve this problem, semi-organic coatings in which some of the coating components are replaced with inorganic substances have been made to compensate for the drawbacks of organic coatings. The actual situation is that it has an adverse effect on the punchability and deteriorates the properties of the film.

Under these circumstances, with regard to organic or semi-organic insulating films, there has been a strong desire to develop a technology that improves the heat resistance of the film and improves the film scorching properties during annealing and the film properties after annealing.

(Problems to be Solved by the Invention) The present invention improves the statesking resistance during stress relief annealing of electrical steel sheets (iron cores) and the slipperiness of copper sheets after annealing, without impairing the film resistance as in the prior art. The object of the present invention is to provide a method for producing a non-oriented electrical steel sheet, which can provide an insulating film with excellent corrosion resistance and electrical insulation, and a surface treatment agent for the electrical steel sheet used in the method.

(Means for solving problems) The gist of the present invention is as follows.

(1) In a method for manufacturing a non-oriented electrical steel sheet, in which a material for a non-oriented electrical steel sheet is processed by a known method and subjected to final annealing, an organic film is applied to the steel sheet and a baking treatment is performed. As a surface treatment agent for 100 parts by weight of one or more of acrylic, styrene, epoxy, vinyl acetate, polyvinyl alcohol resins, or copolymers thereof, the diameter thereof may be adjusted to 1 to 100 μm. Adjusted methyl methacrylate, polyacrylonitrile, polystyrene, sulfonated styrene, cellulose,
A surface treatment agent containing 2 to 30 parts by weight of one or more of silicone, melamine, phenol, polyvinyl alcohol and/or their copolymers and crosslinked particles is applied to a final steel plate with a single-fired finish. A method for producing a non-oriented electrical steel sheet with excellent film properties after strain relief annealing, which comprises coating and baking.

(2) Methyl methacrylate whose diameter is adjusted to 1 to 100 based on 100 parts by weight of one or more of acrylic, styrene, epoxy, vinyl acetate, polyvinyl alcohol resin and/or copolymers thereof. , polyacrylonitrile, polystyrene, sulfonated styrene, cellulose, silicone, melamine, phenol, polyvinyl alcohol and/or copolymers thereof,
A surface treatment agent for non-oriented electrical steel sheet containing 2 to 30 parts by weight of one or more crosslinked particles.

The present invention will be explained in detail below.

In order to meet the needs of iron core processing manufacturers who are customers of non-oriented electrical steel sheets, the inventors of the present invention have conducted extensive research involving extensive experiments, and have found that the problem could not be solved even with the conventional improvement techniques described above. In order to develop a technology that can all at once solve the problems associated with organic component films, such as the sticking property of the film during annealing, the slipperiness of the steel sheet after annealing, the corrosion resistance, and the deterioration of electrical insulation properties. This is what we have come to.

That is, the present inventors found that 70
When a steel plate (iron core) is subjected to heat treatment at a high temperature range of 0 to 800°C, it forms carbon fibers or forms a reaction product with the base resin. It has been newly discovered that the problems in the prior art can be solved by blending in the additive amount.

In the present invention, in a so-called all-organic resin film in which the film component is entirely composed of an organic resin, heat treatment of an electrical steel sheet (iron core) is achieved by adding and blending a specific heat-resistant coarse-grained resin as a film component. At this time, the heat-resistant resin, copolymer, crosslinked product, or reaction product with the base resin is made into carbon fiber and left to form fine irregularities on the surface of the steel sheet to control the surface properties. By controlling the surface properties of the steel sheet, it is possible to prevent the films from seizing on each other during annealing of the steel sheet (iron core).
It prevents sticking) and improves the slipperiness and electrical insulation properties of the steel plate after annealing. Furthermore, when heat-resistant coarse-grained resin is mixed with ordinary acrylic resin, etc.,
When a single organic resin or a mixture of ordinary organic resins is used, the decomposition and combustion of the film components that occur during heat treatment of steel plates (iron cores) are suppressed, and the film remains as a film even after heat treatment, so corrosion resistance is significantly improved. Such effects cannot be obtained at all with ordinary organic resins, but are remarkable when added and used in the specific resin defined in the present invention in its form.

The reason why it is preferable to set the type and blending ratio of the treatment liquid used in the present invention within the range specified in the present invention is as follows.

The treatment liquid used in the present invention has, as a main component, a base organic resin containing one or more of acrylic, styrene, vinyl acetate, epoxy, polyvinyl alcohol resins and/or copolymers thereof. . These resins have excellent film-forming properties, and even when applied thinly, they form a dense film with an excellent appearance, and the slipperiness of the steel plate when punching the steel plate is also good. In addition, since it has relatively good heat resistance, it is stable against drying and baking treatments in the temperature range of 200 to 300°C.

The second component used in the present invention has a diameter of 1 to 1100.
Consisting of one or more of methyl methacrylate, polyacrylonitrile, polystyrene, sulfonated styrene, cellulose, silicone, melamine, phenol, polyvinyl alcohol resin and/or copolymers and crosslinked products thereof prepared in p. It is a particle and is used as an additive.

That is, the present invention is characterized in that the resin in the all-organic resin film is composed of a film-forming resin and a heat-resistant additive resin.

The blending ratio of these organic resins is based on 100 parts by weight of the base resin, and heat-resistant coarse-grained resins, that is, the diameter of the resin is 1 to 100 parts by weight.
One or more of methyl methacrylate, polyacrylonitrile, polystyrene, sulfonated styrene, cellulose, silicone, melamine, phenol, polyvinyl alcohol resins and/or copolymers and crosslinked products thereof adjusted to μm The amount of particles is 2 to 30 parts by weight. If the amount of heat-resistant coarse grain resin added is less than 2 parts by weight, the steel plate (
The effect of improving the weldability of the iron core (iron core) is small, and the formation of fine surface irregularities created by the reaction product with the carbon fiber or base resin after annealing is small, so the heat resistance of the steel plate after annealing is Improvement effects such as the slipperiness and electrical insulation properties of the steel plate cannot be obtained. On the other hand, if the amount added exceeds 30 parts by weight, although the film properties after annealing the steel plate (iron core) are good, the film forming properties are slightly reduced, and the appearance of the film and the punchability of the steel plate are slightly reduced. , the upper limit is 30 parts by weight.

The effect of adding a heat-resistant coarse-grained resin can be obtained by using the above-mentioned resins, but the effect is greater when a copolymer or crosslinked product of the above-mentioned resin is used, or when these are used in combination.

The particle size of the heat-resistant coarse particle resin is 1 to 1100I1.

If it is less than 1 μm, the effect of improving the weldability of the steel plate (iron core) is small, and the desired surface roughness is caused by minute projections of reactants with carbon fiber or base resin after annealing the steel plate (iron core). is not obtained.

In addition, the combustion of base film components during steel plate (iron core) annealing,
The effect of preventing burnout cannot be obtained, and therefore the effect of improving the slipperiness and electrical insulation properties of the steel plate cannot be obtained.

On the other hand, if the particle size exceeds 100 μm, it is possible to improve the weldability of the copper plate (iron core), the slipperiness of the steel plate, and the electrical insulation properties, and to obtain a steel plate with excellent statesking resistance during annealing. , because carbon fiber protrusions become too large and reduce the space factor when laminating steel plates.
The upper limit is 100 μm.

FIG. 1 shows the relationship between the type and amount of the heat-resistant coarse-grained resin and the surface roughness Ra of the steel plate (iron core) after annealing. As is clear from Fig. 1, when using a copolymer and/or a crosslinked product of coarse-grained resin, the heat resistance is better than that of a simple substance, and the surface roughness of the steel plate after annealing of the steel plate (iron core) is (Ra
value) can be increased.

Base resin 5 is made of 70% acrylic and 30% styrene, and methyl methacrylate (as a heat-resistant coarse-grained resin)
The results of measuring the slipperiness of the steel plate after annealing the steel plate (iron core) when varying the amount of particles added (particle size: 35 μm) are shown in the second table.
Shown in Figures (a), (b), (C), and (d).

Figure 2 (a) is a comparative example, with only the base resin, (b) ~
(d) is an example of the present invention in which the amounts of methyl methacrylate added were 5 g, Log, and 20 g, respectively.

As is clear from Figure 2, the slipperiness of the steel plate after annealing is
The results were significantly improved when the amount of coarse resin added was increased, and it can be seen that the surface protrusions of the steel plate after annealing have a large influence.

In addition to the above two resin components, other organic resins may be added to the treatment liquid of the present invention as needed.

Example 1 A treatment agent containing a heat-resistant organic resin having the composition shown in Table 1 was added to the surface of a non-oriented electrical steel sheet with a thickness of 0.5 M treated by a known method at a rate of 2.5 g/dry weight after drying. It was coated with a rubber roll so as to achieve rrf, and baked for 30 seconds at 300°C in a continuous furnace.

A sample was cut out from the steel plate of No. 1, and subjected to strain relief annealing at 750°C for 2 hours.Then, the film burning state of the annealed steel plate and the film characteristics of the annealed steel plate were evaluated.

7 The film characteristics in this test were investigated using the following method.

(1) Punching property: Punching with a steel die. The number of punchings until the burr height reached 50 knots was measured.

(2) Investigation of weldability, welding speed in TIG welding, occurrence of blowholes, etc.

(3) Seizure resistance (state king resistance); 3X3cm
Laminated steel plates cut into layers and tightened at 40kg/C.
Stress relief annealing was performed at 750° CX for 2 hours with tightening at step a. The peeling load of each steel plate was measured to evaluate the seizure state.

(4) Slip property 1) FF value: As shown in Figure 3, a certain load is placed on three stacked steel plates, the center steel plate is pulled, and the FF (Friction Factor) is determined from the relationship between the load and the tensile force.
was measured.

2) Lubricity: A steel ball with a diameter of 10 mm was applied to the surface of the annealed steel plate under a load of 100 g, and the slipperiness (surface resistance) when the ball was moved back and forth was measured.

0 (5) Corrosion resistance test method; steel plate 5 x 10 cm after annealing
Cut out a sample of 50″c x 24h in a constant temperature and humidity chamber.
After performing the treatment under R (humidity 98%), the occurrence of rust was investigated.

(6) Measured by interlayer resistance test method, JIS method 2.

As a result of this test, all the products coated with the treatment agent containing the heat-resistant coarse-grained resin of the present invention had good staking resistance.
The properties of the film after annealing were significantly improved, and especially when the amount added was 10 g or more per 100 g of the base resin, extremely good results were obtained.

It was also found that the punchability results were almost the same as those of conventional organic coatings, and there was no effect due to the addition.

1 Example 2 In the same manner as in Example 1, a treatment agent with a heat-resistant coarse-grained resin having a different particle size as shown in Table 3 was applied, and the treatment was heated at 270°C.
A baking process was performed for 30 seconds. The coating amount at this time was 2.7 g/rrf after baking.

A sample was cut out from this product plate, strain relief annealed in the same manner as in Example 1, and the film properties after annealing were investigated. The results are shown in Table 4.

2 3 As described above, all of the steel sheets to which the heat-resistant coarse-grained resin of the present invention is added have good weldability of the iron core, and after annealing, fine irregularities are formed on the steel plate surface due to the carbon fiber-based reactants. It is formed. In particular, when heat-resistant coarse particle resin with a diameter of 10 or more is added, this fine uneven shape will cause
It is possible to form a film with excellent slipperiness and electrical insulation properties on the steel plate after annealing.

(Effects of the Invention) The present invention provides a surface treatment agent consisting entirely of an organic resin component, by adding and blending a specific heat-resistant coarse-grained resin to the base resin. It is possible to solve the problems of poor weldability, poor slipperiness of the steel plate after annealing, and poor electrical insulation, which were disadvantages of resin coatings.

In particular, it is possible to obtain a non-oriented electrical steel sheet that is free from seizure during strain relief annealing, has good magnetic properties, and has excellent slipperiness and electrical insulation properties.

[Brief explanation of drawings]

Figure 1 shows the type and amount of heat-resistant coarse-grained resin added5, and the roughness R of the steel plate surface (film surface) after steel plate (iron core) annealing.
Figure 2 shows the results of measuring the slipperiness of the steel plate after annealing the steel plate (iron core) when the amount of methyl methacrylate added as a heat-resistant coarse-grained resin was varied. , FIG. 3 is a diagram showing a method of measuring the slipperiness of a steel plate. 6

Claims (2)

[Claims] (1) In a method for manufacturing a non-oriented electromagnetic steel sheet, in which an organic film is applied to a steel sheet that has been processed by a known method and subjected to final annealing, and then subjected to a baking treatment, the organic film is As a surface treatment agent for forming, for 100 parts by weight of one or more of acrylic, styrene, epoxy, vinyl acetate, polyvinyl alcohol resin and/or copolymers thereof, the diameter thereof is 1 to 100 μm. Adjusted methyl methacrylate, polyacrylonitrile, polystyrene, sulfonated styrene, cellulose,
Applying a surface treatment agent containing 2 to 30 parts by weight of one or more of silicone, melamine, phenol, polyvinyl alcohol and/or their copolymers and crosslinked particles to a final annealed steel plate. A method for producing a non-oriented electrical steel sheet with excellent film properties after strain relief annealing, the method comprising: (2) Methyl methacrylate whose diameter is adjusted to 1 to 100 μm per 100 parts by weight of one or more of acrylic, styrene, epoxy, vinyl acetate, polyvinyl alcohol resin and/or copolymers thereof;
Polyacrylonitrile, polystyrene, sulfonated styrene, cellulose, silicone, melamine, phenol,
A surface treatment agent for non-oriented electrical steel sheets containing 2 to 30 parts by weight of one or more of polyvinyl alcohol and/or their copolymers and crosslinked particles.