JP6176181B2 - Laminated electrical steel sheet and manufacturing method thereof - Google Patents

Description

  The present invention relates to a laminated electrical steel sheet produced by laminating and bonding non-oriented electrical steel sheets and a method for producing the same.

  The non-oriented electrical steel sheet is a material used for small high-speed rotating motors such as EV and HEV motors and small high-efficiency transformers. Since iron cores used in these electric devices are used in a high frequency range of several hundred Hz to several kHz from the viewpoint of downsizing and high efficiency of the devices, it is essential to have excellent high frequency characteristics. Specifically, a rapid increase in iron loss with an increase in frequency becomes a problem, and it is first important that the iron core material has excellent iron loss characteristics in a high frequency region.

Under such a background, for example, Patent Document 1 discloses a technique for providing a material excellent in high-frequency iron loss by reducing the eddy current loss by reducing the thickness of the non-oriented electrical steel sheet.
However, in such a thin non-oriented electrical steel sheet, although high-frequency iron loss can be effectively reduced, there remains a problem that productivity of iron core production is lowered. That is, when a user tries to manufacture a thick iron core, which is a thin non-oriented electrical steel sheet, inevitably increases the number of punching steps and the number of laminated assembling steps.

  In order to avoid such problems, it is effective on the steel sheet manufacturer's side to bond several thin non-oriented electrical steel sheets in advance and integrate them together. Technology that applies such methods to electrical steel sheets However, it is disclosed in Patent Document 2, for example.

JP-A-3-223445 JP-A-7-201551

  However, the method proposed in Patent Document 2 assumes that a thin non-oriented electrical steel sheet is once manufactured and then laminated and bonded to form a laminated steel sheet. Such a method has the following problems.

  First, when manufacturing a thin non-oriented electrical steel sheet, if the plate thickness is reduced, the coil length is increased accordingly, and as a result, it takes a lot of time for rolling and annealing, resulting in an increase in manufacturing cost. It is a thing that ends up.

  Secondly, it is necessary to newly add a process of laminating and adhering thin non-oriented electrical steel sheets, which also increases the manufacturing cost.

That is, the laminated steel plate manufactured by the technique described in Patent Document 2 has a problem that it cannot be provided at low cost because it includes a factor that increases the manufacturing cost.
In addition, Patent Document 2 also describes a method of bonding steel plates during the manufacturing process of a thin non-oriented electrical steel sheet, but such a method is not described in the examples and can be implemented. Is not disclosed.

  The present invention was developed in view of the above-mentioned present situation, and proposes a laminated electrical steel sheet having a stable and high iron loss characteristic together with a manufacturing method that can be obtained efficiently without using a costly process. With the goal.

As a means for solving the above problems, the inventors conceived of laminating and adhering steel plates with an adhesive having high heat resistance and insulation before finish annealing, and as a result of earnest studies, the components of the adhesive The various knowledge for solving the said subject was recognized.
The present invention has been made based on the above findings and further studies.

That is, the gist configuration of the present invention is as follows.
1. In mass%, C: 0.05% or less, Si: 7.0% or less, Al: 3.0% or less, Mn: 3.0% or less, P: 0.2% or less, S: 0.01% or less, N: 0.01% or less, and O: 0.01% Two or more non-oriented electrical steel sheets containing the following, the balance consisting of Fe and inevitable impurities, and having a plate thickness of 0.005 to 0.50 mm, three-dimensional roughness: Sa of 0.1 μm or more are B, Mg, Al Bonded with an insulating layer mainly composed of one or more selected from oxides, nitrides and carbides containing at least one of elements of Si, P, Ca and Zr, and a total thickness of 0.10 to 1.0 Laminated electrical steel sheet that is mm.

2. The non-oriented electrical steel sheet is further mass%, Sn: 0.005% to 0.2%, Sb: 0.005% to 0.2%, Ca: 0.0005% to 0.010%, Mg: 0.0005% to 0.010%, REM : 0.0005% to 0.010%, Ti: 0.001% to 1%, Nb: 0.001% to 1%, V: 0.001% to 1%, B: 0.0005% to 0.01%, Cr: 0.1% to 3.0% 2. The laminated electrical steel sheet according to 1 above, comprising at least one selected from Cu and 0.1% or less and Cu: 0.1% or more and 3.0% or less.

3. In mass%, C: 0.05% or less, Si: 7.0% or less, Al: 3.0% or less, Mn: 3.0% or less, P: 0.2% or less, S: 0.01% or less, N: 0.01% or less, and O: 0.01% A slab containing the following, the balance Fe and inevitable impurities, hot-rolled, and then with or without hot-rolled sheet annealing, two or more cold sandwiches with one cold rolling or intermediate annealing. A series of laminated electrical steel sheet manufacturing methods in which rolling is performed and a non-oriented electrical steel sheet having a thickness of 0.005 to 0.5 mm and a three-dimensional roughness Sa of 0.1 μm or more is applied, followed by finish annealing and coating with an insulating film. In
One or more selected from oxides, nitrides and carbides containing at least one of the elements B, Mg, Al, Si, P, Ca and Zr after the cold rolling and before the finish annealing. A method for producing a laminated electrical steel sheet in which two or more steel sheets are laminated with an adhesive as a main component so that the total thickness is 0.10 to 1.0 mm.

4). The slab is further mass%, Sn: 0.005% to 0.2%, Sb: 0.005% to 0.2%, Ca: 0.0005% to 0.010%, Mg: 0.0005% to 0.010%, REM: 0.0005% or more 0.010% or less, Ti: 0.001% to 1%, Nb: 0.001% to 1%, V: 0.001% to 1%, B: 0.0005% to 0.01%, Cr: 0.1% to 3.0% and Cu The method for producing a laminated electrical steel sheet according to 3 above, comprising at least one selected from 0.1% to 3.0%.

  According to the present invention, a laminated electrical steel sheet having stable and high iron loss characteristics can be produced without using a costly process.

Hereinafter, the present invention will be specifically described.
The present invention relates to a laminated electrical steel sheet, which is a laminate of two or more non-oriented electrical steel sheets.
Therefore, first, the reasons for limiting the steel components of the non-oriented electrical steel sheet according to the present invention will be described. In addition, the following% display means the mass% unless there is particular notice. In the present invention, the term “steel plate” simply means a non-oriented electrical steel plate unless otherwise specified.
C: 0.05% or less C can be used for adjusting the strength of the steel sheet. However, if the C content exceeds 0.05%, carbides increase and iron loss significantly deteriorates. Therefore, the upper limit of the C content is 0.05%. When iron loss is regarded as important, C must be 0.005% or less in order to suppress iron loss deterioration due to carbide and magnetic deterioration due to magnetic aging. That is, the preferable range of the C content is 0.005% or less. In addition, although there is no special restriction | limiting in the lower limit of C content, it is about 0.0005% industrially.

Si: 7.0% or less
Si has the effect of increasing the specific resistance of steel and reducing iron loss. However, if added over 7.0%, the steel sheet becomes brittle and rolling becomes difficult. Therefore, the range of Si content is 7.0% or less. Moreover, a preferable range is 1.0% or more and 4.5% or less.

Al: 3.0% or less
Al has the effect of increasing the specific resistance of steel and reducing iron loss. However, if added over 3.0%, the steel sheet becomes brittle and rolling becomes difficult. Therefore, the upper limit of the Al content is 3.0%. It should be noted that when the Al content is in the range of 0.01 to 0.1%, there is a possibility that the fine AlN is increased and the grain growth property is deteriorated. Therefore, the preferable range is 0.01% or less, or 0.1% or more and 1.0% or less. .

Mn: 3.0% or less
Mn has the effect of increasing the specific resistance of steel and reducing iron loss. However, even if added over 3.0%, the effect is weak, so the range of Mn content should be 3.0% or less. In order to avoid hot brittleness, Mn is preferably added in an amount of 0.1% or more, and a more preferable range is 0.1% or more and 1.0% or less.

P: 0.2% or less P can be used for adjusting the hardness of steel. If it exceeds 0.2%, the plate becomes brittle and rolling becomes difficult. Therefore, the range of P content is 0.2% or less. A preferable range is 0.1% or less. In addition, although there is no special restriction | limiting in the lower limit of P content, it is about 0.001% industrially.

S: 0.01% or less When the S content exceeds 0.01%, precipitates such as MnS increase and grain growth properties deteriorate. Therefore, the upper limit of the S content is 0.01%. A preferred range is 0.003% or less. In addition, although there is no special restriction | limiting in the lower limit of S content, it is about 0.0001% industrially.

N: 0.01% or less When the N content exceeds 0.01%, precipitates such as AlN increase and the grain growth property deteriorates. Therefore, the upper limit of the N content is 0.01%. A preferred range is 0.003% or less. In addition, although there is no special restriction | limiting in the minimum of N content, it is about 0.0005% industrially.

O: 0.01% or less When the O content exceeds 0.01%, inclusions such as oxides of Si, Al, and Mn increase, and grain growth properties deteriorate. Therefore, the upper limit of the O content is 0.01%. A more preferable range is 0.003% or less. In addition, although there is no special restriction | limiting in the lower limit of O content, it is about 0.0005% industrially.

Although the essential components in the steel slab have been described above, the following elements can be appropriately contained in the present invention. The balance is Fe and inevitable impurities.
Sn and Sb: 0.005-0.2%
Addition of 0.005% or more of Sn and Sb has the effect of reducing the [111] crystal grains in the recrystallized texture and improving the magnetic flux density. On the other hand, even if added over 0.2%, the effect of addition is small, so the range of Sn and Sb content is preferably 0.005% to 0.2%, respectively. Further preferable ranges are 0.02% or more and 0.1% or less, respectively.

REM, Mg and Ca: 0.0005 to 0.010%
REM, Mg, and Ca all have the effect of coarsening sulfides and improving grain growth by adding 0.0005% or more. On the other hand, if added over 0.010%, the grain growth property is worsened. Therefore, the range of REM, Mg and Ca contents is preferably 0.0005% or more and 0.010% or less, respectively. A more preferable range is 0.001% or more and 0.005% or less for all of REM, Mg and Ca.

Ti, Nb and V: 0.001 to 1%
Ti, Nb and V are all elements that increase the strength of the steel sheet by forming carbides and nitrides. If it is less than 0.001%, there is no effect of addition, but if it exceeds 1%, the cost increases remarkably. Therefore, the contents of Ti, Nb and V are all preferably 0.001% or more and 1% or less.

B: 0.0005-0.01%
B is an element that suppresses embrittlement of the steel sheet, and can be added to improve the rollability. If it is less than 0.0005%, there is no effect of addition, and if it exceeds 0.01%, the iron loss is remarkably deteriorated. Therefore, the B content is preferably 0.0005% or more and 0.01% or less.

Cr: 0.1-3.0%
Cr has the effect of increasing the specific resistance of steel and reducing iron loss. If less than 0.1%, there is no effect, but if added over 3.0%, Cr carbide increases and the iron loss worsens. Therefore, the Cr content is preferably 0.1% or more and 3.0% or less.

Cu: 0.1-3.0%
Cu is an element that increases the strength of steel by precipitating fine Cu particles by aging treatment. If it is less than 0.1%, there is no effect of addition, but if it exceeds 3.0%, the effect is saturated. Therefore, the Cr content is preferably 0.1% or more and 3.0% or less.

Next, the manufacturing process of the laminated electrical steel sheet according to the present invention will be described.
A slab may be produced from molten steel adjusted to the above-mentioned preferred component composition by a normal ingot-bundling method or continuous casting method, or by a direct casting method from a thin cast piece having a thickness of 100 mm or less. May be.
Next, the slab is heated by a normal method and subjected to hot rolling, but may be immediately subjected to hot rolling without being heated after casting. In the case of a thin slab, hot rolling may be performed, or hot rolling may be omitted and the subsequent process may be performed as it is. After hot rolling, hot-rolled sheet annealing may be performed to improve magnetism and prevent ridging.
After hot-rolling or hot-rolled sheet annealing, cold rolling is performed once or two or more times with intermediate annealing between them to finish the target plate thickness. The finished plate thickness here is 0.005 mm or more and 0.50 mm or less.
This is because, if an attempt is made to obtain a plate thickness thinner than 0.005 mm, the rolling time becomes too long and the manufacturing cost becomes remarkably high. On the other hand, if it exceeds 0.50 mm, the high-frequency iron loss increases.

  Here, in the present invention, it is an important point that the three-dimensional roughness of the steel plate: Sa is 0.1 μm or more. This is because when the three-dimensional roughness of the steel plate: Sa is less than 0.1 μm, the anchor effect of the adhesive is not sufficiently exhibited, and the adhesion cannot be maintained. Preferably it is 0.2 μm or more. In the present invention, the three-dimensional roughness of the steel sheet can be easily adjusted, for example, by changing the roll roughness of the tandem rolling mill. For example, the roughness of the finish rolling roll of the tandem rolling mill is set to Sa ≧ 0.1 μm, preferably Sa ≧ 0.2 μm.

  The three-dimensional roughness of the steel plate is measured using a general stylus roughness meter according to the contents described in JIS B0601, JIS B0632, JIS B0633, JIS B0651, etc.

  After the final cold rolling, finish annealing is performed. In finish annealing, since it is necessary to recrystallize and grow grains in the steel sheet, the soaking temperature is preferably set to 800 to 1100 ° C. After finish annealing, if necessary, apply an insulating coating to make a product plate. As the insulating coating, a known one can be used, and an inorganic coating, an organic coating, an inorganic / organic mixed coating, or the like may be used depending on the purpose.

  In addition to the above process, in the present invention, it is necessary to laminate and bond two or more steel plates after final cold rolling and before finish annealing so that the total thickness is from 0.10 mm to 1.0 mm. This is because if the total thickness is less than 0.10 mm, the effect of improving productivity cannot be obtained, and if it is more than 1.0 mm, it is difficult for the user to perform punching.

The adhesive used in the present invention and the resulting inorganic insulating layer need to have heat resistance that can withstand finish annealing, and from the viewpoint of reducing eddy current loss, high insulation is required.
As a result of the study by the inventors, one or more selected from oxides, nitrides and carbides containing at least one of the elements B, Mg, Al, Si, P, Ca and Zr are mainly used. Has been found to form a very effective insulating layer. In the present invention, even a combination (mixture) of oxide, nitride and carbide can be used without any problem.

  From the viewpoint of cost, it is preferable to use each oxide of B, Mg, Al, Si, P, Ca and Zr, which is easy to manufacture and obtain, but in the present invention, as the oxide, nitride and carbide used Specific examples include fine particles and colloids of compounds such as magnesia, alumina, silica, phosphate, borate, calcia, zirconia, zircon, aluminosilicate, aluminum nitride, boron nitride, and mixtures thereof. It is done. Alternatively, it may be a composite oxide of B, Mg, Al, Si, P, Ca, and Zr, a composite nitride, a composite carbide, and a mixture thereof.

  Of these compounds, magnesia, alumina, silica, zirconia, zircon, and aluminosilicate are considered to be particularly suitable from the viewpoints of adhesiveness and insulation. However, oxides, nitrides, and carbides having the above-described elements may be used. For example, the use of the adhesive as a main component is not limited. For example, an adhesive called an inorganic adhesive or a ceramic adhesive.

  Here, “mainly” means that the oxide, nitride and carbide in total in the adhesive layer (insulating layer) after annealing or in the solid content of the adhesive are 50% or more in total, preferably 80 % Is included. The balance may be a component generally contained in a binder or a curing agent. Of course, it is preferable to use a binder and a curing agent containing the above elements. For example, silicate, phosphate, colloidal silica, colloidal alumina, alkyl silicate and the like can be mentioned.

The adhesive can be applied by a publicly known means such as a bar coater or a spray. After application of the adhesive, curing (curing treatment) and post-curing (additional heating) may be performed, but may be omitted if sufficient adhesive strength for handling the coil can be obtained without these treatments.
Moreover, what is necessary is just to follow the hardening method of the steel plate using the adhesive agent according to this invention.

[Example 1]
A slab having the chemical composition shown in Table 1 (the balance is Fe and inevitable impurities) was subjected to slab heating at 1100 ° C. for 30 minutes, and hot rolling was performed to obtain a hot rolled sheet having a thickness of 1.8 mm.
The obtained hot-rolled sheet is subjected to hot-rolled sheet annealing at 1000 ° C. for 30 seconds, pickled, removed the scale, cold-rolled, and finished plate thicknesses shown in Table 1 and 3D A cold rolled sheet having roughness: Sa was obtained.
Furthermore, after washing the cold-rolled plate, spray an adhesive (COTRONICS, Resbond 989 Alumina Ceramic, main component: alumina, solid content: 95%) to an average thickness of 20 μm by spraying After coating, laminating steel plates, curing at 100 ° C for 1 minute, and finishing annealing in dry nitrogen-hydrogen atmosphere at 1000 ° C for 30 seconds to make laminated electrical steel plates, the front and back surfaces of this laminated electrical steel plate An insulating coating was applied to the product plate. For comparison, however, No. 1 in Table 1 was passed through as it was without applying an adhesive and laminating steel plates. About the obtained product board, iron loss _{W10 / 400} was measured by the Epstein test, respectively.
The measurement results are also shown in Table 1.

  From the table, it can be seen that the laminated electrical steel sheet produced according to the present invention maintains the adhesiveness even after finish annealing and has excellent iron loss characteristics.

[Example 2]
The slab having the chemical composition shown in No. 1 in Table 1 above was subjected to slab heating at 1100 ° C. for 30 minutes, and hot rolling was performed to obtain a hot rolled sheet having a thickness of 1.8 mm. This hot-rolled sheet is subjected to hot-rolled sheet annealing at 1000 ° C. for 30 seconds, acid pickled to remove the scale, and then cold-rolled. Finished sheet thickness: 0.20 mm, 3D roughness: Sa A cold-rolled sheet having a thickness of 0.24 μm was obtained.
The cold-rolled sheet was washed, and after applying uniformly to an average thickness of 5 μm by spraying as an adhesive containing 80% or more of the inorganic compound shown in Table 2 in the solid content, 2 steel plates were used. The laminated magnetic steel sheets were laminated one by one and subjected to a curing treatment at 200 ° C. for 1 minute, followed by finishing annealing at 1000 ° C. for 30 seconds in a dry nitrogen-hydrogen atmosphere to obtain a laminated electrical steel sheet. Further, an insulating coating was applied to the front and back surfaces of this laminated electrical steel sheet to obtain a product plate. About the obtained product board, iron loss _{W10 / 400} was measured by the Epstein test.
The measurement results are also shown in Table 2.

  From the table, it can be seen that the laminated electrical steel sheet produced within the scope of the present invention maintains its adhesiveness even after finish annealing and has excellent iron loss characteristics.

Claims (4)

In mass%, C: 0.05% or less, Si: 7.0% or less, Al: 3.0% or less, Mn: 3.0% or less, P: 0.2% or less, S: 0.01% or less, N: 0.01% or less, and O: 0.01% Two or more non-oriented electrical steel sheets containing the following, the balance being Fe and inevitable impurities, and having a thickness of 0.005 to 0.50 mm, three-dimensional roughness: Sa is 0.10 μm or more are B, Mg, Al , P 1 , Ca, and Zr, at least one selected from oxides, nitrides and carbides selected from oxides, nitrides and carbides are bonded together with an insulating layer containing a total of 50% by mass or more. Laminated electrical steel sheet that is 0.10 to 1.0 mm.   The non-oriented electrical steel sheet is further mass%, Sn: 0.005% to 0.2%, Sb: 0.005% to 0.2%, Ca: 0.0005% to 0.010%, Mg: 0.0005% to 0.010%, REM : 0.0005% to 0.010%, Ti: 0.001% to 1%, Nb: 0.001% to 1%, V: 0.001% to 1%, B: 0.0005% to 0.01%, Cr: 0.1% to 3.0% The laminated electrical steel sheet according to claim 1, comprising at least one selected from Cu and 0.1% or less and Cu: 0.1% or more and 3.0% or less. In mass%, C: 0.05% or less, Si: 7.0% or less, Al: 3.0% or less, Mn: 3.0% or less, P: 0.2% or less, S: 0.01% or less, N: 0.01% or less, and O: 0.01% A slab containing the following, the balance Fe and inevitable impurities, hot-rolled, and then with or without hot-rolled sheet annealing, two or more cold sandwiches with one cold rolling or intermediate annealing. A series of laminated electrical steel sheet manufacturing methods in which rolling is performed and a non-oriented electrical steel sheet having a sheet thickness of 0.005 to 0.5 mm and a three-dimensional roughness Sa of 0.10 μm or more is applied, followed by finish annealing and application of an insulating coating In
A total of one or more selected from oxides, nitrides and carbides containing at least one of the elements B, Mg, Al 2 , P 3 , Ca and Zr after the cold rolling and before the finish annealing. A method for producing a laminated electrical steel sheet in which two or more steel sheets are laminated with an adhesive containing 50% by mass or more of the total solid content, and the total thickness is 0.10 to 1.0 mm.   The slab is further mass%, Sn: 0.005% to 0.2%, Sb: 0.005% to 0.2%, Ca: 0.0005% to 0.010%, Mg: 0.0005% to 0.010%, REM: 0.0005% or more 0.010% or less, Ti: 0.001% to 1%, Nb: 0.001% to 1%, V: 0.001% to 1%, B: 0.0005% to 0.01%, Cr: 0.1% to 3.0% and Cu The method for producing a laminated electrical steel sheet according to claim 3, comprising at least one selected from 0.1% to 3.0%.