JP3370235B2 - Method of forming an insulating coating excellent in corrosion resistance and free of chromium compound capable of strain relief annealing on the surface of an electrical steel sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] [0001] The present invention relates to a non-oriented electrical steel sheet.
Excellent corrosion resistance and strain relief annealing
Chromium compound-free insulating coatings
Things. Furthermore, baking at a lower temperature than before is possible.
The present invention provides a method for forming a functional insulating film. [0002] 2. Description of the Related Art Non-oriented electrical steel sheets are mainly used for motors and trucks.
It is used as an iron core such as a ball. At the time of its use,
After continuous punching in the shape of
Anneal or perform strain relief annealing before
After stacking the numbers, welding, caulking, or bonding
It is assumed to be a steel core. Usually on the surface of non-oriented electrical steel sheet
Has an insulating film formed thereon. As this insulating film,
Not only electrical insulation but also corrosion resistance before strain relief annealing
Properties, punching properties, adhesion, weldability, solvent resistance, during strain relief annealing
Resistance, corrosion resistance after strain relief annealing, adhesion, slippage
Versatile characteristics such as high occupancy
Is required to obtain good core properties and workability.
You. A method for forming an insulating film on a non-oriented electrical steel sheet is described below.
1) inorganic type, 2) organic type, 3) organic-inorganic mixed type
Is known. However, 1)
Inorganic insulation coatings of
Although heat resistance and slipperiness after strain relief annealing are excellent,
Poor pullability. On the other hand, in the organic insulating film of 2),
Although it has excellent punching properties and adhesion,
The film is decomposed and destroyed, and seizure resistance and annealing during strain relief annealing
Adhesion afterwards is poor and cannot be used. 3) Organic-inorganic
As a mixed insulating film, Japanese Patent Publication No. 50-15013
In the report, dichromate and vinyl acetate, butadiene-styrene
Organic resin emulsions such as copolymers and acrylic resins
The processing solution as a main component is also described in JP-B-60-36476.
In Japanese Patent Application Laid-Open Publication No. H10-163, 100 parts by weight of chromic anhydride
And the vinyl acetate / veova ratio is 90/10 to 40/60
The resin emulsion corresponding to the ratio is 5 to 1 as a resin solid content.
20 parts by weight and 10 to 60 parts by weight of an organic reducing agent
High space occupation by forming insulating film using physical fluid
Rate, excellent corrosion resistance, adhesion, and punching properties.
In addition, even when performing strain relief annealing, fairly good coating characteristics
The resulting method for forming an insulating film has been proposed. This 3)
The method uses chromic acid for excellent corrosion resistance, adhesion and
Coating treatment method for excellent punchability by adding resin
Occupy the mainstream. [0004] However, the main component is a chromium compound.
Chromium in the coating after baking is hexavalent
Although it is reduced to trivalent and detoxified, its safety and health
A certain response is required. That is, the formation of an insulating film
In the process, it affects the human body in liquid preparation, painting work, etc.
Strict safety and health measures such as protective equipment
is there. In addition, wastewater, wastewater, etc. generated in painting work, etc.
Detoxification treatment that meets the water quality standards set forth in pollution regulations
Must be implemented, and economic problems such as processing costs are also significant.
No. In addition, there are severe environmental issues among consumers of electrical steel sheets.
Currently, the use of chromium compounds is restricted as in Europe
Is to be strengthened. Therefore, it contains chromium compounds
Insulation coating treatment technology that achieves the same characteristics as conventional without
The development of was desired. Furthermore, productivity improvement, energy
From the viewpoint of energy cost reduction, the conventional coating baking temperature (approx.
(300-500 ℃) Baking temperature lower than possible
The development of efficient technologies was also awaited. Contains no chromium compounds
The following are examples of insulating film formation methods that can perform
Techniques are disclosed. Japanese Patent Laid-Open Publication No. Sho 50-103438 discloses that
Phosphate ions in solutions containing one or more phosphates
0.1 to 50 parts by weight of acid soluble per 10 parts by weight
Treatment liquid to which one or more kinds of resin has been added
Apply to the surface and heat and bake at 300-800 ° C to insulate
A technique for forming a coating is disclosed. However,
With this technology, there is a long time to bake below 300 ° C.
However, there is a problem that productivity is poor. Japanese Patent Application Laid-Open No. 54-31598 discloses an organic
Contains a substance and forms a three-dimensional siloxane bond stitch structure
Mainly composed silica gel, plate temperature is 100-35
A method of forming an insulating film by heating at a temperature of 0 ° C. for a short time
It has been disclosed. However, this technology still has
The corrosion resistance was inferior to that of the insulating film containing romic acid. In Japanese Patent Publication No. Sho 59-21927,
Are colloidal silica, alumina sol, colloidal titanium
One or more of lithium, lithium silicate, artificial mica
Aqueous solution mainly composed of an inorganic colloidal substance consisting of
Or 100 parts of this inorganic colloidal substance
Or one or more of the emulsion type resins.
Aqueous solution containing 0.5 to 50 parts of an organic substance
After 0.02-0.8g / m^TwoSteel sheet with a coating of
A technique for forming a film by temper rolling as it is disclosed.
However, this is a simple coat formation technique,
Although the seizure resistance during strip annealing is good,
Other characteristics such as food quality are organic using conventional chromium compounds
-Inferior to the characteristics of the inorganic mixed insulating coating. [0008] JP-A-5-78855 discloses phosphoric acid
Aluminum dihydrogen to P_TwoO_Five100-350 in good conversion
g / l-containing inorganic aqueous solution and synthetic tree having a pH of 1 to 3
Add a fat-based aqueous emulsion, and even crosslinked resin particles
There is disclosed a technique for forming an insulating film by using the method. But
However, in this technique, the baking temperature of the coating is 250 to 500.
It was necessary to be relatively high in ° C. Next, Japanese Patent Application Laid-Open No. 6-330338 discloses
Is based on 100 parts by weight of the first phosphate solution of aluminum.
And an organic resin emulsion having a particle size of 0.2 to 3.0 μm
A processing solution containing 1 to 300 parts by weight as a main component, or
Particles per 100 parts by weight of the first phosphate solution of minium
Organic resin emulsion 1 to 30 having a diameter of 0.2 to 3.0 μm
0 parts by weight, and 1 to 20 parts by weight of boric acid and colloida
Having 1 to 5 parts by weight of silica
A technique for forming an insulating film using a physical solution is disclosed.
You. However, also in this technology, see the embodiment
And the baking temperature of the coating must be 250 ° C or higher
there were. [0010] Further, Japanese Patent Application Laid-Open No. 7-166365 has been disclosed.
Then, in terms of solid content, the molar ratio (Al _TwoO_Three/ H_ThreeP
O_Four) 0.15-0.20 aluminum phosphate, mole
Ratio (CaO / H_ThreePO_FourOr ZnO / H_ThreePO_Four)
One of 0.4-0.6 calcium phosphate and zinc phosphate
Or particle size at pH 4-10 as an organic substance with two or more kinds
A synthetic resin emulsion of 0.3 to 3.0 μm was compounded.
The molar ratio (Al_TwoO_Three/
H_ThreePO_Four) 0.15 to 0.20 aluminum phosphate
System, molar ratio (CaO / H_ThreePO_FourOr ZnO / H_Three
PO_Four) 0.4-0.6 calcium phosphate, phosphorous acid
One or more of lead and phosphoric acid, boric acid, borate
One or more kinds and organic substances are pH 4-10 particles
Contains synthetic resin emulsion with a diameter of 0.3-3.0 μm
Technology for forming an insulating film using a treated processing solution is disclosed.
ing. However, even in this technology, in the embodiment,
The film baking temperature is 250 ° C or higher.
The temperature required the same temperature as before. The chromium compounds disclosed above are included.
Insulating film forming techniques are roughly divided into the following two. a) A treatment solution containing an inorganic colloidal substance and an organic resin
It is used as a base, and baking at low temperatures is possible
However, the corrosion resistance is mainly organic-inorganic containing conventional chromium compounds
It was inferior to the mixed coating. Therefore, technical positioning
Is inexpensive and simple, with lower film properties than before but high productivity.
It was equivalent to a coat. b) Based on a treatment solution containing phosphate and an organic resin
The properties of the film are almost the same as those of conventional chromium compounds.
Performance similar to that of mixed organic-inorganic coatings
Since it contains phosphate as a basic composition, to ensure corrosion resistance
Is the temperature at which the phosphate dehydration reaction occurs, as the baking temperature
(About 250 ° C or higher)
It cannot be burned. Also, it has a great influence on the formation of the insulating film.
Baking conditions (temperature rise rate,
Cooling rate, annealing atmosphere dew point, etc.)
Insulation film formation technology that does not contain compounds has been studied
did not exist. In the method of forming an insulating film containing a chromium compound,
The following techniques are disclosed as baking conditions. In Japanese Patent Application Laid-Open No. 54-24233, punching
In order to obtain a coating film with good performance,
X (250 ≦ X ≦ 500 [° C.]) and heating time Y (30 ≦
Focusing on the relationship of Y ≦ 150 [sec], the additive in the processing solution
X and Y are satisfied by the blending amount of (ethylene glycol)
And the steel sheet surface temperature is 80 to 100 ° C.
Technology to increase the heating rate in the range of 0.5 to 10 ° C / sec.
It is shown. In Japanese Patent Application Laid-Open No. Sho 60-190572,
In order to obtain a film with excellent pullability and weldability,
In both cases, the temperature rises between 110 ° C and 150 ° C.
Temperature rate: The temperature was raised under the conditions of 2 to 10 ° C./sec, and subsequently 25
Disclosure of technology to complete baking in a temperature range of 0 to 350 ° C
Have been. Also, in JP-A-2-38581,
In order to secure an end coating film without defects such as blisters,
After applying the treatment liquid, heat it at a temperature rise rate of 2 to 5 ° C / sec.
After the steel plate temperature reaches 350-450 ° C,
To reduce the water content of the coating to 2% by weight or less.
I have. In Japanese Patent Application Laid-Open No. 3-53077, the coating
In order to obtain a coating without falling, at 130 ° C or more during the heating process
Set the regulated temperature in the temperature range below the baking temperature,
Until the temperature is reached, regulate the heating rate to 15 ° C / sec or less
There is disclosed a technique for increasing the temperature. Next, Japanese Patent Laid-Open No. 3-5
No. 6679 also obtains a coating free from coating defects.
Therefore, in the heating process, heat at a heating rate of 20 ° C / sec or less.
A technique for increasing the temperature is disclosed. In Japanese Patent Application Laid-Open No. Hei 3-232977, punching
Treatment liquid to obtain a film with excellent heat resistance, weldability and heat resistance.
Along with the composition, a rate of 3-20 ° C / sec up to a temperature of 150 ° C
The temperature rises at the heat rate and then to the temperature range of 250-450 ° C.
And a baking process is disclosed. Ma
Also, in Japanese Patent Application Laid-Open No. 4-99878, after the strain relief annealing,
In order to form a coating with excellent corrosion resistance and adhesion,
Along with the composition of the physical solution, 300-
A technique for baking in the range of a plate temperature of 600 ° C. is disclosed.
I have. Furthermore, Japanese Patent Application Laid-Open No. Hei 5-287545
In order to obtain a film with excellent weldability,
Have a dew point below the temperature of the steel sheet before reaching 60 ° C
Technology for baking after spraying gas onto the coating surface has been developed.
It is shown. In other words, the baking conditions
In the case of a processing solution containing a chromium compound,
Despite some disclosure of technology related to
For the case where a processing solution containing no ROM compound is used,
Conventionally, it has not been considered at all. Furthermore, the heating rate and the cooling
Reject speed, baking atmosphere dew point, etc.
, Regardless of whether it contains chromium compounds or not
No technology relating to formation is disclosed. [0018] SUMMARY OF THE INVENTION A chromium compound is not contained.
In addition, conventional organic-inorganic mixed coating containing chromium compound
Strain removal with excellent film properties, especially excellent corrosion resistance before annealing
Has the ability to perform annealing and has lower temperature baking than before.
Insulation coating with low energy cost and high productivity
The present invention provides a forming method. [0019] Means for Solving the Problems The present inventors have made the above-mentioned description.
As a result of earnest research to solve the problem, inorganic colloidal substances
Of the coating film using a treatment solution containing
Coating amount and baking conditions, i.e., baking temperature,
Temperature rate, cooling rate, dew point of baking atmosphere, steel plate and baking
By controlling the relative velocity of the atmosphere gas,
Coating characteristics similar to organic-inorganic mixed coatings containing chromium compounds
Strain relief annealing, especially excellent in corrosion resistance before strain relief annealing is possible
It has excellent performance and can be baked at a lower temperature than before.
Found that it is possible to form an insulating film that does not contain
did. Organic-inorganic mixed system containing no chromium compound
In the coating, the corrosion resistance before strain relief annealing is at a good level.
In order to form a certain coating, the baking and drying process of the coating
Dehydration process and film formation process behavior control become more important in
In addition to the heating rate and cooling rate during baking,
Dew point of atmosphere gas and steel plate and atmosphere gas
Only by controlling the relative speed of
A film having excellent corrosion resistance was obtained. That is, according to the present invention, annealing is performed in a continuous annealing line.
Non-directional that forms an insulating coating on the steel sheet surface after performing the dulling
In the method for producing an electromagnetic steel sheet, the insulating film is formed
Colloidal silica, alumina
Or one or more inorganic zirconia sols
For 100 parts by weight of colloidal substance (inorganic substance conversion)
One or more water-soluble or emulsion-type resins
Is 15 to 400 parts by weight of an organic substance composed of two or more
Using the added aqueous solution, determine the amount of
0.2-1.5 g / m per side in quantity^TwoPainted on steel sheet as
After the cloth, the heating rate is 10 ° C / sec or more,
Seconds, baking atmosphere dew point 20 ℃ or less, plate temperature 100 ~
In the temperature range of 250 ° C, with steel plate and baking atmosphere gas
Baking at a relative speed of 3m / sec to 10m / sec
Capable of performing strain relief annealing with excellent corrosion resistance
This is a method for forming an insulating film containing no chromium compound. At the time of baking, the dew point of the atmosphere gas should be 20 ° C. or less.
Low and the relative speed between the steel sheet and the atmosphere gas is 3 m /
Seconds or more so that the surface of the steel
Moisture generated from the treated solution spreads quickly into the atmosphere.
Dispersed and immediately low dew point (low moisture) atmosphere
Exposure to gaseous gases accelerates dehydration and film formation.
To form a dense, low-moisture film.
For this reason, it is considered that a film having excellent corrosion resistance is obtained. However
And the relative speed between the steel sheet and the atmosphere gas exceeds 10 m / sec.
If so, the appearance deteriorates, which is not preferable. Hereinafter, the experimental results of the present invention will be described.
Will be explained. As the treatment liquid for forming an insulating film of the present invention,
Colloidal silica, alumina sol, zirconia sol 1
100 or more inorganic colloidal substances consisting of two or more species
Water-soluble or emulsion based on parts (in terms of inorganic substances)
Organic materials consisting of one or more of these resin types
Aqueous solution to which 15 to 400 parts by weight (in terms of organic matter) is added
I have. The inorganic colloidal substance used in the present invention is
One type of Lloyd-like silica, alumina sol, zirconia sol
Or, it is composed of two or more types. Also colloidal
Silica has a surface treated with alumina or the like.
May be used. Good as an inorganic colloidal substance
Preferred is colloidal silica. The inorganic colloid
The material has seizure resistance during strain relief annealing and after strain relief annealing.
Necessary to ensure the corrosion resistance, adhesion, and slipperiness of
You. The organic substance used in the present invention may be water-soluble or emulsified.
It is also composed of one or more of the lugion type resins.
It is. The water-soluble or emulsion type resin
Is necessary to ensure punching and corrosion resistance. Water soluble
Acrylic or emulsion type resins
, Polystyrene, epoxy, vinyl acetate, polyethylene
, Polyester, polyolefin, phenol, poly
Vinyl alcohol, polypropylene, polyurethane, etc.
A mixture of one or more kinds can be used.
You. However, other than the above, those which are consistent with the gist of the present invention
Of course, is within the scope of the present invention.
Preferred organic resins are acrylic, epoxy,
It is polyethylene. In the treatment liquid for forming an insulating film of the present invention
In addition, sila involved in the binding of inorganic colloidal substances and organic substances
Additives such as coupling agents.
You. Mixing a silane coupling agent etc. can improve adhesion
And an effective means for further improving solvent resistance. Further
Organic substances having a rust-preventing effect, such as amines, NaN
O_Two, NaMoO_FourCorrosion resistance when a passivating agent such as
Helps improve sex. Water-soluble or emulsion type resins
About the addition amount, 100 parts by weight of the inorganic colloidal substance
15 to 400 parts by weight, preferably 30 to 250 parts by weight
Parts by weight. If the amount is less than 15 parts by weight, the
It is not preferable because of poor pull-out and corrosion resistance. 400 weight
If the amount exceeds the limit, seizure resistance during strain relief annealing, strain relief annealing
The subsequent corrosion resistance and adhesion are inferior and are not preferred. Next, the above treatment liquid composition composition is applied to the steel sheet surface.
The amount of coating after coating and baking is calculated by the weight after drying.
0.2-1.5 g / m per surface^Two, Preferably 0.4 to
1.2g / m^TwoAnd 0.2 g / m coating amount^TwoLess than
Cannot provide sufficient punching properties and corrosion resistance, etc.
^TwoIf it exceeds the limit, the coating characteristics such as punching properties will be commensurate with the increase in coating amount.
Not only no improvement in weldability, but also poor weldability
I do. The baking temperature is preferably 100 to 250 ° C.
Or 150-200 ° C. Chromium compound of the present invention
-Free inorganic colloidal substance and water-soluble or emulsion
In the case of treatment liquids mainly composed of
Lower temperature baking is possible and the plate temperature exceeds 250 ℃
The organic matter added will be decomposed and scattered, resulting in a good coating
Since the characteristics cannot be obtained, the upper limit of the baking temperature is 250
° C. On the other hand, when the plate temperature is less than 100 ° C.,
It takes a long time to scatter and the residual moisture after baking increases.
The lower limit of the baking temperature is 100 ° C.
And [0028] Among the baking conditions, the temperature rise rate is 10 ° C.
/ Sec or more, preferably 20 to 100 ° C / sec. 1
At a slow heating rate of less than 0 ° C / sec, this chromium compound
Free from water-soluble or emuljo
Using a treatment liquid with a composition mainly composed of
In this case, it was found that the resulting coating had poor corrosion resistance.
Although the detailed mechanism is unknown, the processing with the above configuration
In the physical solution, baking is performed by allowing the dehydration reaction to proceed promptly.
The residual moisture content in the subsequent coating is reduced, and
It seems to improve. The cooling rate during baking is 50 ° C./sec or less.
Below. At high cooling rates of over 50 ° C / sec,
Occasionally, defects such as cracks occur on the surface of the insulating film, resulting in deterioration of corrosion resistance
Therefore, the cooling rate was limited as described above. Coating baking
Normally used atmosphere such as air, nitrogen, argon, etc.
This is performed using gas. However, the above-mentioned treatment liquid formulation is used
Baking temperature 100-250 ° C, heating rate during baking
At a temperature of 10 ° C / sec or more, and a baking cooling rate of 50 ° C / sec or less
Even if an insulating film is formed under the conditions, its corrosion resistance is
Often it was inferior to the insulating coating containing the compound. So
Here, as a result of further studying the conditions for baking,
Dew point of ambient air and relative velocity between steel plate and baking atmosphere gas
Has a significant effect on corrosion resistance before strain relief annealing
Was. Hereinafter, the experimental results will be described. [0031]Dew point of atmosphere gas and steel plate and atmosphere gas
Examination of relative speed with Under the following conditions, the dew point of the baking atmosphere should be less than 0 ° C to 5
0 ° C, whether the relative speed between the steel sheet and the baking atmosphere gas is 0 m / sec
And baking was performed by changing the temperature to 11 m / sec. In addition, steel
The relative speed between the plate and the baking atmosphere gas depends on the passing speed of the steel plate.
Or, it was changed by changing the flow rate of the baking atmosphere gas. Burning
FIG. 1 shows the results of the corrosion resistance after the indentation. Corrosion resistance (wet test)
Is a temperature of 50 ° C and a relative humidity after baking and before strain relief annealing.
Rusted area ratio after exposure for 48 hours under 100% condition (%)
Was measured. In FIG. 1, the evaluation was performed as follows.
Was. If the rusting area ratio is less than 5%, the evaluation rank is ○.
20% was rated as Δ, and more than 20% was rated as x. However, the appearance deteriorates
Are marked with *. Treatment liquid composition Colloidal silica (silica sol with a concentration of 20%): 50 layers
Parts (SiO_Two10 parts by weight) Emulsion type resin; acrylic acid / styrene (solid
40% resin emulsion): 25 parts by weight Silane coupling agent (having acrylic group): 0.3
Parts by weight (3% based on resin solids) Rust inhibitor: 0.2 parts by weight (2 based on silica + resin solids)
%) Water: 325 parts by weight Coating weight: 0.5 g / m^Two(Per side) From the above, the dew point of the baking atmosphere should be 20 ° C. or less.
Below, and the relative speed between the steel sheet and the baking atmosphere gas is 3 m
/ Sec or more, equivalent to a coating containing a chromium compound
Good corrosion resistance (Rust rate less than 5% in 48Hr wet test)
Was obtained. However, the relative speed is 10 m /
After more than a second, streaks and unevenness of the film become noticeable,
Since the appearance deteriorated, the upper limit was set to 10 m / sec. The reason why a film having excellent corrosion resistance can be obtained is as follows.
Reduces the dew point of the ambient gas to 20 ° C or less,
Increase the relative speed between the plate and the atmosphere gas to 3 m / sec or more
In this way, the processing liquid applied to the steel sheet surface during
The generated water quickly diffuses into the atmosphere, and
Exposed to low dew point (low moisture) atmosphere gas
Therefore, dehydration and film formation proceed quickly, and
This is probably because a film with little residual moisture is formed. What
The baking atmosphere gas type is air, nitrogen, argon, etc.
Normally used ones may be used. [0035] Next, examples of the present invention will be described together with comparative examples.
You. (Example 1) Non-oriented electrical steel sheet (final thickness after final finish annealing)
0.5 mm) on the surface is treated with a treatment liquid X having the following composition.
The basis weight after drying with mulol is 0.5 g / m per side^Two
And apply a baking treatment under the conditions shown in Table 1.
went. After that, various quality tests of the coating shown below were performed.
Was. The results are also shown in Table 1. In addition, conventional chromium compounds
As a typical example of an organic-inorganic mixed film containing
Composition and baking strip described in JP-A-36476
As a result of investigating the characteristics of the coating obtained from the sample No. 1
1 is shown in Table 1. The treatment liquid composition (Y) and baking
The conditions for the application are also shown below. Composition of treatment liquid X Colloidal silica (silica sol with a concentration of 20%): 50 layers
Quantity Emulsion type resin; polyethylene / acrylic acid type
(Resin emulsion with a solid content of 25%): 40 parts by weight Silane coupling agent (having acrylic group): 0.3
Parts by weight (3% based on resin solids) Rust inhibitor: 0.2 parts by weight (2 based on silica + resin solids)
%) Water: 310 parts by weight Composition of treatment liquid Y 30% magnesium dichromate solution: 130 parts by weight (C
rO_Three32.5 parts by weight) Vinyl acetate-veova resin emulsion (resin solid content 50
%): 20 parts by weight Ethylene glycol: 10 parts by weight Coating weight: 0.5 g / m^Two(Per side) Film baking conditions: baking for 80 seconds in a hot air oven at 450 ° C [Quality test conditions]Product plate (before annealing) 1) Interlayer resistance: According to JIS second method. 2) Adhesion: diameter (mmφ) that bends and does not peel off the coating 3) Corrosion resistance (wet test): temperature 50 ° C, relative humidity 100
Measure rusting area ratio (%) after 48 hours exposure under% condition 4) Solvent resistance: Soak xylene into absorbent cotton, 10 rounds
Evaluate the appearance after re-rubbing Evaluation rank ○ (good) → △ → × (poor) 5) Punching performance: In the case of a 15mmφ steel die
Punching number until the height reaches 50 μm (10,000 sheets / 5
0 μm) 6) Weldability: TIG welding, welding without blowholes
Speed limit (cm / min) [0039]Heat resistance during strain relief annealing 7) Heat resistance: 750 ° C. with many test pieces laminated
× 2Hr, dry N_TwoAnnealed under atmospheric conditions. That
Later, the presence or absence of seizure is determined.After strain relief annealing 8) Interlayer resistance: According to JIS second method. 9) Corrosion resistance (wet test): temperature 50 ° C, relative humidity 100
Measure rusting area ratio (%) after 5 hours exposure under% condition 10) Adhesion: diameter (mm
φ) [0040] [Table 1] According to the conditions of the present invention, a chromium compound is contained.
The same film properties as before can be obtained without strain.
Excellent corrosion resistance before removal annealing and good other coating properties.
That the coating was obtained at a lower baking temperature than before
You. Example 2 Nondirectional Electricity after Final Finish Annealing
On the surface of magnetic steel sheet (sheet thickness 0.5mm),
A processing solution having the composition shown in Table 2 based on the additive was added to a rubber
The basis weight after drying with a roll is 1 g / m per side^TwoIs
After uniform application, the temperature rise rate is 30 ° C / sec.
Temperature 150 ° C, holding time 5 seconds, cooling rate 25 ° C / second, baking
Dew point of the baking atmosphere 0 ° C, relative speed of steel sheet and baking atmosphere gas
The baking treatment was performed under the condition of 6 m / sec. Then implemented
Various coating quality tests were performed as in Example 1. Table 2 shows the results
It is described together. [0043]Main agent and additive of processing solution Colloidal silica (silica sol with a concentration of 20%) Emulsion type resin; epoxy / acrylic acid type (solid
25% form resin emulsion) Silane coupling agent (having acrylic group): resin solid
5% for form Rust inhibitor: 3% based on silica + resin solids [0044] [Table 2]Under the conditions of the present invention, corrosion resistance before strain relief annealing
That a film with excellent properties and good other film properties was obtained.
Understand. Example 3 Nondirectional Electricity after Final Finish Annealing
On the surface of a magnetic steel sheet (sheet thickness 0.5 mm),
The basis weight after drying the treatment liquids A to D with a rubber roll hit one side.
0.7 g / m^TwoAfter applying evenly so that
Speed 50 ° C / sec, reached plate temperature 200 ° C, holding time 3sec, cold
Cooling speed 30 ° C / sec, dew point of baking atmosphere less than 0 ° C, steel plate
Baking under conditions of relative speed of baking atmosphere gas and 7m / s
Processing was performed. After that, various products of the coating were formed as in Example 1.
A quality test was performed. Table 3 shows the results. In addition, conventional cross
As a typical example of an organic-inorganic mixed coating containing a rubber compound,
Japanese Patent Application Laid-Open No. Hei 4-308094
The baking conditions are shown below with the composition of the processing solution E and the baking conditions.
Of the coating obtained under the composition and baking conditions
The evaluation of the characteristics is also shown in Table 3. [0047]Composition of treatment liquid A Colloidal silica (silica sol with a concentration of 20%): 50 layers
Parts (SiO_Two10 parts by weight) Emulsion type resin; epoxy / ester type (solid
25% resin emulsion): 40 parts by weight Silane coupling agent (having acrylic group): 0.3
Parts by weight (3% based on resin solids) Rust inhibitor: 0.2 parts by weight (2 based on silica + resin solids)
%) Water: 310 parts by weight [0048]Composition of treatment liquid B Colloidal silica (silica sol with a concentration of 20%): 50 layers
Quantity Emulsion type resin; polyethylene / methacrylic acid
System (solid content 25% resin emulsion): 40 parts by weight Silane coupling agent (with vinyl group): 0.1 weight
Amount (1% based on resin solids) Rust inhibitor: 0.3 parts by weight (3 parts per silica + resin solids)
%) Water: 310 parts by weight [0049]Composition of treatment liquid C Alumina sol (20% alumina sol): 50 weight
Department Water-soluble resin; cationic epoxy resin (20% solid content)
(Water-soluble resin): 50 parts by weight Rust inhibitor: 0.2 parts by weight (2 based on silica + resin solids)
%) Passivating agent; NaMoO_Four: 1 parts by weight Water: 300 parts by weight [0050]Composition of treatment liquid D Zirconia sol (concentration of 20% zirconia sol): 50
Parts by weight Emulsion type resin; polyester / urethane tree
Fat (water-soluble resin having a solid content of 20%): 50 parts by weight Rust inhibitor: 0.3 parts by weight (3 parts per silica + resin solids)
%) Passivator; NaNO_Two: 1 parts by weight [0051]Composition and baking conditions of treatment liquid E 30% magnesium dichromate solution: 100 parts by weight (C
rO_ThreeConversion amount) Vinyl acetate-ethylene copolymer emulsion (solid resin)
50%): 60 parts by weight Glycerin: 30 parts by weight Coating weight: 0.7 g / m^Two(Per side) Film baking conditions: baking for 70 seconds in a hot air oven at 450 ° C [0052] [Table 3] According to the conditions of the present invention, a chromium compound is contained.
The same film properties as before can be obtained without strain.
Excellent corrosion resistance before removal annealing and other coating properties.
That the coating was obtained at a lower baking temperature than before
You. [0054] EFFECTS OF THE INVENTION The composition of the processing solution for forming an insulating film according to the present invention
And chrome baking conditions.
Equivalent to the conventional organic-inorganic mixed coating containing chromium compound
Coating properties are obtained, that is, corrosion resistance before strain relief annealing
Insulation film with excellent properties and other film characteristics
I understood. The insulating coating of the present invention does not contain a chromium compound.
There are few problems with complete hygiene,
It can respond to environmental problems. In addition, baking at lower temperature than before
To improve productivity and reduce energy costs
This is also advantageous.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing the influence of the dew point of the baking atmosphere and the relative speed between the steel sheet and the atmosphere gas on the corrosion resistance after baking and before the strain relief annealing at the time of baking the insulating film.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Keiji Sato 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama Pref. JP-A-63-35746 (JP, A) JP-B-59-21927 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 22/00-22/86 B05D 7/14

Claims (1)

(57) [Claim 1] In a method for manufacturing a non-oriented electrical steel sheet in which an insulating film is formed on a steel sheet surface after annealing in a continuous annealing line, a surface for forming the insulating film is provided. As a treatment agent,
Colloidal silica, alumina sol, zirconia sol 1
100 parts by weight (in terms of inorganic substance) of an inorganic colloidal substance composed of one or more kinds, and 15 to 400 parts by weight (in terms of organic substance) of an organic substance composed of one or more of water-soluble or emulsion type resins. ) Using the added aqueous solution, the applied amount is 0.2 to
After applying to a steel sheet at 1.5 g / m ² , the heating rate was 10
At a cooling rate of 50 ° C./sec or more, a baking atmosphere dew point of 20 ° C. or less, and a sheet temperature of 100 to 250 ° C.
A method for forming an insulating coating not containing a chromium compound and capable of performing strain relief annealing excellent in corrosion resistance, wherein the baking is performed at a relative speed between the steel sheet and the baking atmosphere gas of 3 m / sec or more and 10 m / sec or less.