Technical field
[0001]
　The present invention relates to an electromagnetic steel sheet.
Background technique
[0002]
　Electrical steel sheet or used in a corrosive environment, or is transported. For example, electromagnetic steel plates or used in areas of high temperature and high humidity, or it is marine transportation. At the time of the maritime transport, a large amount of salt comes flying. Therefore, the electrical steel sheet rust resistance is required. Insulating film on the surface of the electrical steel sheet in order to obtain rust resistance is formed. As the insulating film, and a chromate-based insulation coating. Salt-based insulating film chromic acid show excellent rust resistance but hexavalent chromium, which is used as a raw material for chromate-based insulating film having a carcinogenic. Therefore, the development of the insulating coating which can be formed without the use of hexavalent chromium in the raw material has been demanded.
[0003]
　Hexavalent chromium can be formed without using a raw material insulating coating as phosphate-based insulating film, and a silica-based insulating film, and zirconium-based insulating film (Patent Documents 1 to 12). However, these in the insulating film, no rust resistance comparable to salt chromic acid-based insulating coatings were obtained. Although improved rust resistance when thick insulating coatings, weldability and crimping properties as insulating film is thick is reduced.
CITATION
Patent Literature
[0004]
Patent Document 1: JP-B 53-028375 Patent Publication
Patent Document 2: JP-A 05-078855 JP-
Patent Document 3: JP-A-06-330338
Patent Document 4: JP-A 11-131250 JP
Patent Document 5: JP 11-152579 JP
Patent Document 6: JP 2001-107261 Patent Publication
Patent Document 7: JP 2002-047576 JP
Patent Document 8: WO 2012/057168 Patent
Patent Document 9: JP 2002-47576 JP
Patent Document 10: JP 2008-303411 JP
Patent Document 11: JP 2002-249881 JP
Patent Document 12: JP 2002-317277 JP
Summary of the Invention
Problems that the Invention is to Solve
[0005]
　The present invention aims to provide an electromagnetic steel sheet can provide excellent rust resistance hexavalent chromium without the material of the insulating coating.
Means for Solving the Problems
[0006]
　The present inventors have conducted extensive studies to solve the above problems. As a result, it was found that excellent rust resistance when the relationship between the amount of substance of substance amount and Fe of P contained in the insulating film is relevant. The formation of such an insulating film, was also revealed that is possible to use a coating solution containing a chelating agent is important.
[0007]
　The present inventors have found that further intensive studies based on these findings, and conceived to aspects of the invention described below.
[0008]
　(1)
　and the base material of the electromagnetic steel,
　and an insulating film formed on the surface of the base material
　has,
　the insulating coating, Al, Zn, 1 or more selected from the group consisting of Mg and Ca containing phosphate,
　electromagnetic steel sheets, wherein the ratio of the amount of substance of the Fe atoms to amount of substance P atom (mol) of the insulation in the coating (mol) of 0.1 ultra 0.65.
[0009]
　(2)
　electrical steel sheet according to the insulation coating, characterized in that it contains an organic resin (1).
Effect of the invention
[0010]
　According to the present invention, since the relationship between the amount of substance of substance amount and Fe of P contained in the insulating coating it is appropriate, to obtain an excellent rust resistance hexavalent chromium without the material of the insulating coating can. Therefore, it is possible to avoid a decrease in weldability and crimping properties due to thickening of the insulating coating.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011]
[1] Figure 1 is a cross-sectional view showing the structure of an electromagnetic steel sheet according to the embodiment of the present invention.
[Figure 2A] Figure 2A is sodium chloride concentration is a diagram illustrating an example of a 1.0% by weight of the rust resistance test results.
[Figure 2B] Figure 2B is a concentration of sodium chloride is a diagram illustrating an example of a 0.3% by weight of the rust resistance test results.
[Figure 2C] Figure 2C, sodium chloride concentration is a diagram illustrating an example of a 0.1% by weight of the rust resistance test results.
FIG 2D] FIG 2D is sodium chloride concentration is a diagram illustrating an example of a 0.03 mass% of rust resistance test results.
FIG 2E] FIG 2E is sodium chloride concentration is a diagram illustrating an example of a rust resistance test results of 0.01 wt%.
[Figure 3A] Figure 3A is a diagram showing an example of a rust resistance test results of the electromagnetic steel plates forming the insulating film using a coating solution containing no chelating agent.
[Figure 3B] Figure 3B is a diagram showing an example of a rust resistance test results of the electromagnetic steel plates forming the insulating film using a coating solution containing a chelating agent.
DESCRIPTION OF THE INVENTION
[0012]
　Hereinafter, with reference to the accompanying drawings, it will be described in detail embodiments of the present invention. Figure 1 is a cross-sectional view showing the structure of an electromagnetic steel sheet according to the embodiment of the present invention.
[0013]
　The electrical steel sheet 1 according to the embodiment of the present invention, as shown in FIG. 1, includes base member 2, and the insulating film 3 formed on the surface of the base 2 of electrical steel. Base material 2 has a composition suitable for grain-oriented electrical steel sheet or non-oriented electrical steel sheet.
[0014]
　Insulating coating 3, Al, Zn, contain one or more phosphate salts selected from the group consisting of Mg and Ca. Ratio of amount of substance of the Fe atoms to the amount of substance (mol) of the P atoms in the insulating coating in 3 (mol) of 0.1 Ultra 0.65. Hereinafter, sometimes the amount of substance of Fe atoms to the amount of substance (mol) of the P atom ratio of (mol) as "Fe / P molar ratio", Al, Zn, Mg or Ca, or any combination thereof in M there be represented.
[0015]
　Insulation coating 3 having a Fe / P molar ratio as described above is dense than the insulating film included in conventional electromagnetic steel sheets, it has excellent rust resistance. Therefore, according to the electrical steel sheet 1, it is possible to obtain the hexavalent chromium without the material of the insulating coating 3, an excellent rust resistance without reducing the weldability and crimping properties.
[0016]
　As Fe / P molar ratio is high, the insulating film 3 showed excellent water resistance, Fe / P molar ratio is 0.1 or less can not be obtained sufficient water resistance. Therefore, Fe / P molar ratio is 0.1 greater. On the other hand, the Fe / P molar ratio of 0.65, more than likely cause cracks in the insulating film 3, there is the moisture from entering from cracking. Therefore, Fe / P molar ratio is 0.65 or less.
[0017]
　Fe / P molar ratio, for example, can be identified as follows. For example, 80 ° C. electromagnetic steel sheet temperature, concentration was immersed in 20 wt% aqueous NaOH solution for 30 minutes, thereby an insulating film is dissolved in aqueous NaOH solution. Then, the substance amount of Fe and P contained in the NaOH aqueous solution (mol) inductively coupled plasma (inductively coupled plasma: ICP) is quantified by analysis. Then, to calculate the Fe / P molar ratio of the insulating coating from these substances amounts.
[0018]
　Next, a method for manufacturing the electrical steel sheet 1. In this way, by applying a polyvalent metal phosphate containing M, a coating solution comprising a chelating agent and water to the base material of the electromagnetic steel, baking. The water, the total concentration of Ca ions and Mg ions used as the 100ppm or less. The polyvalent metal phosphate, aluminum primary phosphate, the first zinc phosphate, the first magnesium phosphate and a first calcium phosphate are exemplified. Hereinafter, aluminum phosphate, zinc phosphate, magnesium phosphate, calcium phosphate shows a first aluminum phosphate respectively, the first zinc phosphate, magnesium primary phosphate, the first calcium phosphate.
[0019]
　Terminal ends of phosphate during the baking of the coating liquid insulation coating is formed by crosslinking in dehydration condensation reaction. As Scheme dehydration condensation reaction, it is exemplified as follows. Here, it is described as "HO-R-OH" a chelating agent.
　H 3 PO 4 + H 3 PO 4　→ (OH) 2 PO-P (OH) 2 + H 2 O (Formula 1)
　H 3 PO 4 + Fe → FePO 3 + H 2 O (Formula 　2) Fe + 2HO-R-OH → HO-R-O-Fe-O-R-OH + H 2　(formula 3)　2H 3 PO 4 + HO-R-OH 　　→ (OH) 2 PO-R-O-P (OH) 2 + 2H 2 O (formula 　4) HO-R-O-Fe-O-R-OH + (OH) 2 P-O-R-O-P (OH)

2
　　→ HO-R-O-Fe-O-R-O-P (OH) -O-R-P (OH) 2 + H 2 O (5化学式)
[0020]
　As described above, the dissolution reaction of iron by the chelating agent coating solution phosphate alone crosslinking reaction and phosphate salts of formula 2 of the formula 1 in the case of using free occurs. When using a coating solution containing a chelating agent, instead of Formula 2, a chelating agent of Formula 3 and reaction with iron, incorporating a chelating agent of formula 4 crosslinking reaction of phosphoric acid salt, and Formula 5 iron and chelating agent cross-linking reaction of the captured phosphoric acid salt occurs. The crosslinked structure phosphate by the reaction of Formula 3 to Formula 5, the insulating coating rust resistance is improved densified.
[0021]
　The chelating agent, for example, oxycarboxylic acid, a dicarboxylic acid or phosphonic acid-based chelating agent used. As oxycarboxylic acid chelating agent, malic acid, glycolic acid and lactic acid are exemplified. As dicarboxylic acid chelating agent, oxalic acid, malonic acid and succinic acid. The phosphonic acid chelating agent, an amino trimethylene phosphonic acid, hydroxy ethylidene mono acid and Hiroki shea diphosphonic acid.
[0022]
　The amount of the chelating agent included in the coating solution is 1% by mass to 30% by weight, based on the weight of the insulation coating after baking. The chelating agent is less than 1 wt%, by the reaction of Formula 2, FePO not crosslink 3 large amount generated, Fe / P molar ratio of 0.65 super, and the rust resistance is deteriorated due to cracking of the insulating coating. The crosslinking reaction of Formula 3 to Formula 5 if the amount of the chelating agent is not less than 1 mass% progresses, the insulating coating rust resistance is improved densified. Therefore, the amount of chelating agent is 1 mass% or more with respect to the mass of the insulating film after baking. On the other hand, the amount of chelating agent is more than 30 wt%, occurs passivation of the surface of the base by a chelating agent, the reaction is inhibited Fe / P molar ratio of Formula 3 is less than 0.1, incorporating Fe I cross-linked structure is not developed. Therefore, the amount of chelating agent is less than 30% by weight, relative to the weight of the insulation coating after baking.
[0023]
　Although chelating agents are active compounds, energetically become stable upon reaction with metal, not exhibit sufficient activity. Therefore, to maintain a high activity of the chelating agent, a metal other than the metal contained in the phosphate salt is not reacting with the chelating agent prior to baking of the coating liquid is completed. Therefore, it is preferable that low concentrations of highly reactive metal ions with water chelating agent. Such metal ions, Ca ions and Mg ions are exemplified. The total concentration of Ca ions and Mg ions in 100ppm exceeds, decreases the activity of the chelating agent. Therefore, the total concentration of Ca ions and Mg ions are at 100ppm or less and preferably 70ppm or less. The less well Ca ions and Mg alkaline earth metal ions other than ion.
[0024]
　Chelating agent has a hydroxyl group at a terminal, hydroxyl groups easy to take the association state (hydrogen bond) represented by the Chemical Formula 6.
　R-OH ··· O = R (chemical formula 6)
[0025]
　When the hydroxyl of the degree of association of the chelating agent (the degree of hydrogen bonding) is high, the crosslinking reaction hardly occurs of Formula 3 to Formula 5. Therefore, application of the coating solution is preferably performed as the degree of association is as small as possible. For example, when performing coating using a roller (roll coating) is a shear force imparted to the coating solution, it is preferable to apply the coating solution while reducing the degree of association of the chelating agent. The diameter of the roller is reduced, and, by increasing the moving speed of the base material, it is possible to impart a proper shearing force to solve the associated state. For example, it is preferable that a diameter of more than 60 m / min the moving speed of the base material with the following roller 700 mm, that the moving speed of the base material to 70m / min or more using the following roller 500mm diameter more preferable.
[0026]
　Baking of the coating solution is performed at temperatures above 250 ° C., the temperature of the base material, for example, Atsushi Nobori rate of about 30 ° C. from room temperature to 100 ° C. (first heating rate) and 8 ° C. / sec or more at the time of application, heating rate from 0.99 ° C. to 250 ° C. (second heating rate) lower than the first heating rate. Temperature during coating is equal to the temperature of substantially the coating solution.
[0027]
　Progress meeting the foregoing chelating agents, it does not occur if there are no fluidity of the coating solution. Therefore, in order to make the degree of association as low as possible, the first heating rate up to the boiling point of water (100 ° C.) is preferably high. In a less than 1 heating rate 8 ° C. / sec, since the increased association of the chelating agent is rapidly during warm, the crosslinking reaction hardly occurs of Formula 3 to Formula 5. Therefore, the first heating rate is set to 8 ° C. / sec or more.
[0028]
　Formula 1, the decomposition of the crosslinking reaction as well as chelating agents of Formula 3 to Formula 5 of phosphate and chelating agent takes place in a temperature range of 0.99 ° C. - 250 ° C.. Therefore, by decreasing the second heating rate from 0.99 ° C. to 250 ° C., it can promote the crosslinking reaction while suppressing the degradation of the chelating agent. Crosslinking reaction using a chelating agent is affected by the degree of association of the foregoing chelating agents. Therefore, the first heating rate is increased, if reducing the degree of association of the chelating agent, even when the second heating rate is increased, can accelerate the reaction of Formula 3 to Formula 5. In contrast, the first heating rate is small and the degree of association of the chelating is large, unless lower second heating rate accordingly, be sufficiently advanced reaction of Formula 3 to Formula 5 Can not. The study of the present inventors, and the first heating rate 8 ° C. / sec or more, if the second heating rate is lower than the first heating rate, Formula 3 and Formula according to degree of association of the chelating agent 5 reaction proceeds, it has been found that excellent rust resistance is obtained in the. However, if the second heating rate is extremely large, for example in 18 ° C. / sec greater, even first heating rate 8 ° C. / sec or more, the reaction of Formula 3 to Formula 5 is less likely to proceed, excellent was rust resistance can not be obtained. Therefore, the second heating rate is set to 18 ° C. / sec or less. On the other hand, the second heating rate is higher productivity is lowered low, it becomes significant at less than 5 ° C. / sec. Therefore, the second heating rate is preferably between 5 ° C. / sec or more.
[0029]
　It is possible to manufacture the electrical steel sheet 1 through the coating and baking of the coating liquid to the base material of such an electromagnetic steel.
[0030]
　The coating solution may contain an organic resin. The organic resin contained in the coating liquid comprises an action to suppress the wear of the punching die. Thus, by using a coating solution containing an organic resin, punching of the electrical steel sheet is improved. The organic resin is preferably used as water-dispersible organic emulsion. When water dispersible organic emulsion is used, Ca ions contained therein, alkaline earth metal ions such as Mg ions is preferably as small as possible. As the organic resin, an acrylic resin, an acrylic styrene resin, alkyd resin, polyester resin, silicone resin, fluorine resin, polyolefin resins, styrene resins, vinyl acetate resins, epoxy resins, phenolic resins, urethane resins and melamine resins.
[0031]
　Next, the operation of the chelating agent.
[0032]
　When using a coating solution containing no chelating agent attempts to form an insulating film, becomes excessive reaction with phosphate and base metal, Fe / P molar ratio is 0.65 greater. As described above, the Fe / P molar ratio of 0.65 than, cracking is likely to occur in the insulating film. On the other hand, it is possible to suppress the reaction by using a coating solution containing a corrosion inhibitor, in this case, it is Fe / P molar ratio becomes 0.1 or less, no sufficient water resistance can not be obtained .
[0033]
　For these, when forming an insulating film by using a coating solution containing a chelating agent, compound of Fe and chelating agent are formed in the initial relatively low temperature range of baking, after which, the compound at a relatively high temperature range decomposition is, Fe is incorporated in the insulating film. Then, Fe this taken into insulating coating contributes to the improvement of rust resistance.
[0034]
　Here will be described an evaluation method for rust resistance.
[0035]
　As a test for evaluating the rust resistance of the electrical steel sheet, salt spray test stipulated in the wet test and JIS Z 2371 is specified in JIS K 2246 are exemplified. However, corrosive environments in these tests is greatly different from the corrosive environment, such as rust caused in the magnetic steel sheets, necessarily, it can not be said that the rust resistance of the electrical steel sheet can be properly evaluated.
[0036]
　Accordingly, the present inventors have examined how you can properly evaluate the rust resistance in corrosive environments, such as rust electrical steel sheet is produced. As a result, it was found that the rust resistance can be suitably evaluated by the following method. In this way, the droplets of aqueous sodium chloride solution having a different concentration on the surface of the electrical steel sheet having an insulation coating is dried by attaching each 0.5 [mu] l, temperature of 50 ° C., a relative humidity RH of 90% constant temperature and humidity electromagnetic steel plates to hold 48 hours to an atmosphere. It may be used thermo-hygrostat. Thereafter, to confirm the presence or absence of rust, to identify the concentration of sodium chloride rust in the electrical steel sheet does not occur. Then, to evaluate the rust resistance based on the concentration of sodium chloride rust is not generated.
[0037]
　That is, in this way, electromagnetic steel sheets are exposed to a humid atmosphere after deposition and drying of the droplets of aqueous sodium chloride solution. Such processes, storage, transportation and adhered salt on the surface of the electrical steel sheet during use, that then salt humidity rises to is deliquescent, similar to a corrosive environment where electromagnetic steel plates are exposed . Higher concentration of sodium chloride is high, the amount of sodium chloride remaining after drying is often prone to rust. Accordingly, performs observation while the concentration of the aqueous sodium chloride solution stepwise decreased, the concentration of rust is not generated (hereinafter sometimes referred to as "limit sodium chloride concentration") if identifying, on the basis of this limit concentration of sodium chloride , it is possible to evaluate the rust resistance in corrosive environments in which the electromagnetic steel sheets are actually exposed quantitatively.
[0038]
　Figure 2A ~ Figure 2E, shows an example of the test results by the above method. In this test, the concentration of sodium chloride, 1.0 wt% (Fig. 2A), 0.3 wt% (FIG. 2B), 0.1 wt% (Fig. 2C), 0.03 wt% (Fig. 2D) or 0 was .01% by weight (Fig. 2E). Then, as shown in FIGS. 2A ~ Figure 2E, the concentration of sodium chloride is 1% by mass, 0.3% by weight, rust was confirmed in the case of 0.1 wt% or 0.03 wt%, the concentration of sodium chloride There rust was not observed in the case of 0.01 mass%. Therefore, limit the sodium chloride concentration of the electrical steel sheet is 0.01 wt%. The present inventors have also exceeded the retention time in the atmosphere of constant temperature and humidity is 48 hours, I am sure that such rust situation hardly changes.
[0039]
　Figure 3A, shows an example of the test results by the above method for electrical steel sheet to form an insulating film using a coating solution containing no chelating agent, in Figure 3B, the insulating coating with a coating solution containing a chelating agent an example of a test result by the method for forming the electromagnetic steel sheets. Also it includes phosphoric acid as aluminum polyvalent metal phosphate salt to any of the coating solution. In the electromagnetic steel plates forming the insulating film using a coating solution containing no chelating agent, as shown in FIG. 3A, the concentration rust was observed when using a 0.03 mass% aqueous sodium chloride solution. On the other hand, in the electromagnetic steel sheets forming the insulating film using a coating solution containing a chelating agent, as shown in FIG. 3B, the concentration rust is not confirmed even in the case of using a 0.2 wt% aqueous sodium chloride solution.
[0040]
　Thus, in the case of forming an insulating film by using a coating solution containing a chelating agent, than the case of forming the insulating film using a coating solution containing no chelating agent, high limit sodium chloride concentration, excellent rust resistance can be obtained.
[0041]
　Then, an insulating film 3 according to the embodiment of the present invention, Fe / P molar ratio is 0.1 ultra 0.65. Therefore, according to the electrical steel sheet 1, it is possible to obtain an excellent rust resistance hexavalent chromium without the material of the insulating coating 3. For example, electromagnetic steel sheets 1 also at high airborne under salinity environments such as during sea transport, also exhibit sufficient rust resistance in a high temperature and high humidity environment corresponding to the subtropical or tropical. It is not necessary to form a thick insulating film 3, can avoid a decrease in weldability and crimping properties.
[0042]
　The above embodiments are all merely illustrate concrete examples of implementing the present invention, in which technical scope of the present invention should not be limitedly interpreted. That is, the present invention is its technical idea or without departing from the essential characteristics thereof, can be implemented in various forms.
Example
[0043]
　Next, a description will be given of an embodiment of the present invention. Conditions in examples are an example of conditions adopted for confirming the workability and effects of the present invention, the present invention is not limited to this single example of conditions. The present invention does not depart from the gist of the present invention, as long as they achieve the object of the present invention, it is capable of adopting various conditions.
[0044]
　The present inventors have found that phosphate salts shown in Table 1, a chelating agent, to prepare a coating solution composed of an organic resin and water, which was baked was applied to both surfaces of the base material of the electromagnetic steel. The total concentration of Ca ions and Mg ions contained in the water (ion total concentration) is also shown in Table 1. Conditions and baking conditions of the coating are also shown in Table 1. The first heating rate is heating rate from 30 ° C. to 100 ° C., the second heating rate is temperature increase rate up to 150 ℃ ~ 250 ℃. Preform comprises 0.3 wt% to Si, the thickness of the preform was 0.5 mm. Sample No. In 17, for reference, to form an insulating film with a chromate in place of phosphate.
[0045]
[Table 1]

[0046]
　It was then evaluated for the measurement as well as rust resistance and weldability of the Fe / P molar ratio of the insulating coating.
[0047]
　In the measurement of the Fe / P molar ratio of the insulating coating, first, 80 ° C. electromagnetic steel sheet temperature, concentration was immersed in 20 wt% aqueous NaOH solution for 30 minutes, and the insulating coating is dissolved in aqueous NaOH solution. Then, the substance amount of Fe and P contained in the NaOH aqueous solution (mol) was quantified by ICP analysis. Then, to calculate the Fe / P molar ratio of the insulating coating from these substances amounts. The results are shown in Table 2. Underlined in Table 2 indicates that the value is out of range of the present invention.
[0048]
　In the evaluation of the rust resistance, to prepare a test piece from the electromagnetic steel plates, a drop of aqueous sodium chloride solution having a different concentration and dried to adhere by 0.5μl on the surface of the specimen, temperature of 50 ° C., relative humidity RH is a specimen to an atmosphere of 90% constant temperature and humidity was maintained for 48 hours. The concentration of sodium chloride aqueous solution, 0.001 mass%, 0.01 mass%, 0.02 mass%, 0.03 mass%, 0.10 mass%, 0.20 mass%, 0.30 mass% and 1 was 2.0 mass%. Thereafter, to confirm the presence or absence of rust was identified limitations sodium chloride (NaCl) concentration of each specimen. The results are also shown in Table 2.
[0049]
　In the evaluation of weldability, a welding current and 120A, La-W a (2.4mmφ) used as an electrode, the gap and 1.5 mm, the flow rate of the Ar gas 6l / min, a clamping pressure 50 kg / cm 2 as They were welded at different welding speed. Then, to identify the maximum welding speed which blowholes are not generated. The results are also shown in Table 2.
[0050]
[Table 2]

[0051]
　As shown in Table 2, the samples are within the scope of the present invention No. 10 ~ No. In 16, both 0.10 wt% or more limitations sodium chloride concentration and 100 cm / min welding speed is obtained. That is, it provides excellent rust resistance and weldability.
[0052]
　Sample No. 1 ~ No. 9 and No. 18 ~ No. In 21, since Fe / P molar ratio was not in the range of 0.1 ultra 0.65, or even at the limit concentration of sodium chloride 0.03 wt%, the welding speed is or was 50 cm / min. In other words, rust resistance or weldability or both is low.
Industrial Applicability
[0053]
　The present invention is, for example, can be used in industrial application of the manufacturing industry and electrical steel sheet of the electromagnetic steel sheets.

The scope of the claims
[Claim 1]
　And the base material of the electromagnetic steel,
　and an insulating film formed on the surface of the base material
　has,
　the insulating coating, Al, Zn, 1 or more phosphate salts selected from the group consisting of Mg and Ca containing,
　electromagnetic steel sheet, wherein the ratio of the amount of substance of the Fe atoms to amount of substance P atom (mol) of the insulation in the coating (mol) of 0.1 ultra 0.65.
[Claim 2]
　Electrical steel sheet according to claim 1, wherein the insulating coating, characterized in that it contains an organic resin.