JPS63186826A - Production of grain-orientated silicon steel plate having super low iron loss - Google Patents

Abstract

PURPOSE:To produce a grain-orientated silicon steel plate having super low iron loss, by irradiating an electron beam on insulating film of the steel plate toward traversing direction to rolling direction after coating the insulating film having phosphate and colloidal silica as main composition to the orientated silicon steel plate. CONSTITUTION:The insulating coating film having the phosphate and the colloidal silica as main composition is coated on the orientated silicon steel plate after completing the finish annealing of a secondary recrystallized annealing and purified annealing. Before coating the above film, as necessity requires, the above the surface oxide of the above steel plate is removed and next, after the surface is mirror-finished, extremely thin tension coating of nitriding, carbide oxide, etc., of Ti, Zr, etc., may be coated by CVD, etc. Next, on the above insulating coating film, the electron beam irradiation is executed toward traversing direction to rolling direction. The above irradiation is desirable to execute at the interval of about 0-15mm toward about 60-90 deg. to the rolling direction. In this way, film quantity of the insulating coating is changed, and magnetic domain is made to fine and even if the high temp. stress relief annealing is executed, the low iron loss characteristic without deterioration is obtd.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for producing a super core loss unidirectional silicon steel sheet, and in particular, it relates to a method for producing a super core loss unidirectional silicon steel sheet, and in particular, it relates to a method for producing a super iron loss unidirectional silicon steel sheet, and in particular, it relates to a method for producing a super iron loss unidirectional silicon steel sheet, and in particular, a method for manufacturing a super iron loss unidirectional silicon steel sheet, and in particular for producing a mirror finish on a coating film formed after finish annealing or a mirror finish after finish annealing. After applying CVD, ion brating, or ion implantation treatment of nitride, carbide, oxide, etc. on the steel plate surface, an insulating coating film is formed on the tension film, and the rolling direction is controlled on the film. The aim is to achieve ultra-low iron loss by applying EB irradiation in the transverse direction.

Remarkable development efforts in recent years to improve the electrical and magnetic properties of unidirectional silicon steel sheets, and in particular to meet the extreme requirements of reducing iron loss, are gradually bearing fruit.

As is well known, unidirectional silicon steel sheets are products in which secondary recrystallized grains are highly concentrated in the (110) <001>, or Goss, orientation, and are mainly used in transformers and other electrical equipment. When used as an iron core, the product is required to have a high magnetic flux density (represented by the Bl value) and a low iron loss (WB/s, represented by the value) as electromagnetic properties.

This unidirectional silicon steel plate is manufactured through a wide variety of complicated processes, but numerous inventions and improvements have been made so far, and today the magnetic properties of a product with a thickness of 0.30 mm are BIG.
Value 1.90T or more, WIT/S. The magnetic properties of products with a value of 1.05/kg or less or a plate thickness of 0 or 23n+m are 8
1° value 1.89T or more, 1. /,. Value 0.90 匈/k
Unidirectional silicon steel sheets with ultra-low iron loss of less than 100 g are now being manufactured.

Particularly in recent years, demand for reducing power loss has become much stronger from an energy-saving perspective, and in Europe and the United States, when creating a transformer with low loss, the reduction in iron loss is converted into a monetary value and added to the transformer price.・The "evaluation" (iron loss evaluation) system is becoming widespread.

(Prior art) Under these circumstances, recently, the surface of a unidirectional silicon steel plate after finish annealing is irradiated with a laser in a direction substantially perpendicular to the rolling direction to introduce local microstrain to subdivide the magnetic domains. It has been proposed to reduce iron loss by this method (see Japanese Patent Publication No. 57-2252, Japanese Patent Publication No. 57-53419, Japanese Patent Publication No. 5B-26405 and Japanese Patent Publication No. 58-26406).

This magnetic domain refining technology is effective for transformer materials for laminated core transformers that are not subjected to strain relief annealing, but for material for wound core transformers that are subjected to strain relief annealing,
The disadvantage is that the local minute strain introduced by laser irradiation is released by the annealing process and the magnetic domain width becomes wider, thereby eliminating the laser irradiation effect.

On the other hand, earlier in Japanese Patent Publication No. 52-24499, the surface of the steel plate after finish annealing of a unidirectional silicon steel sheet was polished to a mirror finish, or the mirror finish surface was plated with metal or an insulating coating was applied thereon. A method for manufacturing ultra-low core loss unidirectional silicon steel sheets by coating and baking has been proposed.

However, this method of improving the steel structure by mirror finishing cannot be adopted from a process perspective, as it does not contribute enough to reducing iron loss at the cost of significantly increasing the cost. Due to problems with adhesion after coating, it has not been adopted in the current manufacturing process.In addition, in Japanese Patent Publication No. 56-4150, a thin film of oxide ceramics is deposited after mirror-finishing the surface of the steel plate. However, this method cannot be used in actual manufacturing processes because the steel sheet and the ceramic layer separate when subjected to high-temperature annealing at 600° C. or higher.

Furthermore, Japanese Patent Application Laid-Open No. 59-229419 proposes a method of forming thermally strained regions by locally applying thermal energy to the surface of a silicon steel plate.

However, this preferential formation of local thermal strain regions has the disadvantage that its effect is lost by high-temperature annealing at 600° C. or higher.

(Problems to be Solved by the Invention) It is an object of the present invention to compensate for the above-mentioned disadvantages and achieve a significant reduction in iron loss.

(Means for Solving the Problems) This invention involves forming an insulating coating film containing phosphate and colloidal silica as main components on a finish annealed grain-oriented silicon steel sheet, and then rolling the film on the film in the rolling direction. A method for producing an ultra-low iron loss unidirectional silicon steel sheet (first invention) characterized by applying EB irradiation in a direction transverse to Then, after polishing the steel plate surface to a mirror-like state with a center line average roughness Ra of 0.4 μm or less, CV
D, Ti, Zr by ion blating or ion implantation.

Hf, V, Nb, Ta, Cr, M
o + W, Mn + Co + Ni + AI
, B, nitride and/or carbide of Si and 81
1 An ultra-thin tension film made of at least one selected from oxides of Nl + Cu, wl Si, and Zn is formed, and an insulating coating film whose main components are phosphate and colloidal silica is further formed. A method for producing an ultra-low core loss unidirectional silicon steel sheet (second invention), which is characterized in that EB irradiation is then performed on the coating in a direction transverse to the rolling direction.

The explanation will proceed according to specific experiments that led to the success of these inventions.

C: 0.046% by weight (hereinafter simply expressed as %), Si:
3.44%, Mn: 0.068%, Se: 0.0
21%, Sb: 0.025% and Mo: 0.013
A continuously cast silicon steel slab containing 2.0% was heated at 1350°C for 4 hours and then hot rolled. A hot-rolled sheet with a thickness of On+m was obtained.

After that, after homogenization annealing at 900℃ for 3 minutes, at 950℃ for 3 minutes.
Cold rolled twice with intermediate annealing for 0.2 min.
A final cold-rolled sheet with a thickness of 3 mm was obtained.

Thereafter, after decarburization and second recrystallization annealing in a wet hydrogen atmosphere at 820°C, the steel plate surface was coated with inert Alz (h (75%
) and MgO (25%), followed by secondary recrystallization annealing at 850°C for 50 hours and 1200°C.
Purification annealing was performed in soft hydrogen at ℃ for 5 hours.

A part of the obtained finish annealed plate was subjected to the following treatments shown in (al and (bl).

(Electron beam irradiation (EB irradiation, acceleration voltage: 5
0kV, acceleration current: 0.75mA, beam diameter 0. IN
φ, beam scanning interval: 10 mm).

(b) Finish After applying an insulating coating film mainly composed of phosphate and colloidal silica on the surface of the annealed plate, it was irradiated with EB in a direction perpendicular to the rolling direction in vacuum under the same conditions as fa) above.

For comparison, (finish annealed plate without CIEB irradiation and +d) insulating coating was applied after final annealing, and EB
A product plate without irradiation was also prepared.

Furthermore, the surface of the remaining finish annealed plate was lightly pickled (10%
After chemical polishing in a solution of 3% IP and HzO□ to give a mirror finish with an average surface roughness of 0.03 μm, the specimens were divided into four groups and treated under the following conditions. did.

(a) A thin film of TiN with a thickness of 1.0 μm was formed on a mirror-finished steel plate using a continuous ion brating device (ICD method).

ff) After forming a 1.0 μm thick TiN film on a mirror steel plate using a continuous ion plating device,
Subsequently, EB irradiation was performed in a direction perpendicular to the rolling direction in a vacuum (acceleration voltage: 45 KV, acceleration current: 0.75 mA).

Beam diameter: o, i: beam scanning interval: 10 mm).

(gl After forming a 1.0 μm thick TiN film on a mirror steel plate using a continuous ion blating device,
An insulating coating film mainly composed of phosphate and colloidal silica was applied.

fh) A thin film of TiN with a thickness of 1.0 μm was formed on a mirror-polished steel plate by continuous ion blating treatment, and then an insulating coating film mainly composed of phosphate and colloidal silica was applied, and then the film was coated in a vacuum. EB irradiation was performed in the direction perpendicular to the rolling direction under the same conditions as above (fl).

The magnetic property values of each sample subjected to the above treatment are summarized in Table 1.

Table 1 As is clear from Table 1, EB irradiation was performed on a normal unidirectional silicon steel finish annealed plate (a) and ~)
The magnetic properties in the case of B1° value are 1.90 to 1.91T,
WI? 150 value is 0.82-0.83W/kg, EB
The WI7150 value is improved by 0.05 to 0.06 W/kg compared to the magnetic properties in the case of no irradiation (C1 and (d)).Furthermore, the TiN'#1 .The magnetic properties in the case of (f) and (hl) in which EB irradiation was performed after the film was formed are B10.
Value is 1.91-1.92T, W+tzs. value is 0.65
~0.66W/kg without EB irradiation (el and (
g) Compared to the magnetic property values in case (7), WI? /S. The value has improved by 0.05 to 0.07147 kg.

Thus, by applying EB irradiation to a unidirectional silicon steel finish annealed plate after insulating coating treatment, or by mirror-finishing a unidirectional silicon steel finish annealing plate, coating it with an ultra-thin tension film of TiN, and then insulating it. After coating, a product with extremely low core loss can be obtained by EB irradiation.

(Function) Figure 1 shows (a), (b), if), (h
) shows the change in iron loss characteristics after annealing the product.

As is clear from the figure, (b) and (h
), the iron loss characteristics will not deteriorate even if a high-temperature annealing treatment is performed afterwards. Although the reason why the iron loss characteristics do not deteriorate even after high-temperature treatment has not been completely elucidated, it has been found that when EB irradiation is performed on an insulating film in a vacuum, qualitative changes occur in the insulating film. Since the EB irradiation region and the non-irradiation region are non-uniform, it is possible to refine the magnetic domains even if high-temperature annealing is performed, and therefore it is considered that deterioration of iron loss characteristics does not occur.

After applying an insulating coating on a finished annealed plate as shown above, or forming a tension coating on a mirror-finished steel plate surface and then forming an insulating coating on top of that, the insulating coating By performing EB irradiation on the insulating film, it is possible to change the film quality of the insulating film and refine the magnetic domains, and even if high-temperature strain relief annealing is performed, the iron loss characteristics do not deteriorate.

Next, the manufacturing process of a unidirectional silicon steel plate according to the present invention will be explained.

The starting material is a conventionally known unidirectional silicon steel material, such as: C: 0.01 to 0.050%, Si: 2.
50-4.5%, Mn: 0.01-0.2%, M
o: 0.003~0.050 Sb: 0.005~
0.2%, a total of one or two types of S or Se,
Composition containing 0.005 to 0.05%■ C2
0.01 to 0.050. Si: 2.0 ~
4.0%, S: 0.005 to 0.050.
81: 0.005 to 0.06%, N: 0.0
01-0.01%, Sn: 0.01-0.5
%, Cu: 0.01 to 0.3%.

Composition containing Mn: 0.01 to 0.2% ■C:
0.011-0.06%, Si: 2.0-4.0%
, S: 0.005~0.05%, B: 0.0003~
0.0040%, N: 0.001~o, oi%,
It is applicable to compositions containing Mn: 0.01 to 0.2%.

Next, the hot-rolled sheet undergoes uniform annealing at 800 to 1100°C.
One-time cold rolling method, in which the final plate thickness is obtained by two cold rolling steps, or two-step cold rolling method, in which intermediate annealing is usually performed at 850°C to 1050°C, and then further cold rolling is performed.In the latter case, the first rolling rate is 50
% to about 80%, the rolling reduction rate of 1144% is from 50% to 80%.
At about 5%, the final cold-rolled sheet thickness is from 0.15 mm to 0.35 mm.

After finishing the final cold rolling, the steel plate finished to the product thickness is subjected to decarburization and primary recrystallization annealing treatment in wet hydrogen at 750°C to 850°C after surface degreasing.

Thereafter, an annealing separation material containing MgO as a main component is usually applied to the steel plate surface.

At this time, if it is essential to form a forsterite film after final annealing, an annealing separator containing MgO as a main component is generally applied, but if forsterite is not to be formed, the steel sheet is then mirror-polished. Since it is effective in simplifying the process, Al2O2 and ZrO are used as annealing separators.
2. It is preferable to use an annealing separator containing 50% or more of MgO, such as TiO2.

After that, secondary recrystallization annealing is performed, but this step is (110)
This is carried out to sufficiently develop secondary recrystallized grains with the <001> orientation, and is usually performed immediately after box annealing.
This is done by raising the temperature to 00°C or higher and maintaining it at that temperature.

In this case, in order to develop a highly uniform secondary recrystallized grain structure in the (110) <001> orientation, the
It is more advantageous to carry out retention annealing at a low temperature of 00°C, and in addition, for example, 0.5-b annealing may be used.

Purification annealing after secondary recrystallization annealing requires annealing in soft hydrogen at 1100° C. or higher for 1 to 20 hours to achieve purification of the steel sheet.

Thereafter, an insulating film containing phosphate and colloidal silica as main components is further formed.

Next, EB is applied on this insulating coating in a direction transverse to the rolling direction, preferably in a direction of 60 to 90 degrees, at intervals of about 3 to 15 nm.
Apply irradiation. The EB irradiation conditions at this time are 10 to 100K.
It is effective to use an accelerating voltage of V, a current of 0.005 to IOmA, and a beam diameter of 0.005 to 1n to apply the beam in a dotted or linear manner.

Furthermore, if the oxide film on the surface of the steel plate is removed by pickling with a strong acid such as sulfuric acid, nitric acid, or hydrofluoric acid, or by mechanical grinding or cutting, the magnetic properties are further improved.

Next, by conventionally known methods such as chemical polishing and/or electrolytic polishing, the steel plate surface is polished to a mirror-like state, that is, to a center line average roughness R.
A is finished to 0.4 μm or less.

Afterwards, Ti+Zr+V+N is formed by CVD, ion plating or ion implantation.
b.

Ta, Cr, Mo, W, Mn, Got Ni
, A1.8. Si nitride and/or carbide, AL
0.05-5 μm consisting of at least one selected from oxides of Nt, Cu+W, St and Zn
Forms an ultra-thin film of approximately

Then, an insulating film containing phosphate and colloidal silica as main components is formed thereon.

After that, on this insulating coating, Ha
Apply irradiation. The EB irradiation conditions at this time are the same as those described above.

The silicon steel plate treated as described above can be heat-treated for strain relief and flattening at temperatures of 600° C. or higher without deteriorating its core loss characteristics.

(Example) 2 soil group-1 C: 0.045%, St: 3.40%, Mn:
0.066%, -〇=0.020%, Se: 0.
A hot rolled sheet containing Sb: 0.020% and Sb: 0.025% was uniformly annealed at 900°C for 3 minutes and then cold-rolled twice with an intermediate annealing at 950°C to obtain a sheet of 0.23mm. A thick final cold-rolled sheet was obtained.

After decarburization annealing in wet hydrogen at 820°C, Mg is deposited on the steel plate surface.
After applying an annealing separator mainly composed of O, it was heated at 850℃ for 5
Secondary recrystallization annealing was performed for 0 hours, and purification annealing was performed in dry hydrogen at 1200° C. for 8 hours.

After that, after forming an insulating film mainly composed of phosphate and colloidal silica, 7111
EB irradiation linearly at intervals (heating voltage = 45 ν).

Current: 1. OmA, spot diameter is 0.15mφ)
I did it. After that, annealing was performed at 800°C for 3 hours in a nitrogen atmosphere, and the magnetic properties of the product were B. The value is 1.91
T.

WIT/S. The value was 0.82 W/kg.

Apical base-plexus C: 0.052%, Si: 3.46%, Mn:
0.077%, A1: 0.024%, S: 0.0
020%, Cu: 0.1%, Sn: 0.06%
The hot-rolled sheet containing the following was uniformly annealed at 1130°C for 3 minutes and then rapidly cooled, and then warm-rolled at 300°C to obtain a final cold-rolled sheet with a thickness of 0.20 mm.

After decarburization annealing in wet hydrogen at 850°C, Alz (
After applying an annealing separator containing h (80%), MgO (15%) and Zr0z (5%) as main components, it was heated from 850°C to 11
After secondary recrystallization by raising the temperature to 50°C at a rate of 10°C/hr, purification annealing was performed at 1200°C for 8 hours in dry hydrogen.

After that, after removing the oxide film by pickling, add 3% HF and H2O.
, Chemically polished in liquid to give a mirror finish, then CVD.

By ion blating (HCD method) and ion implantation, (1) BN, (21Ti(CN))
, f3) SiJ*.

(4) VN, f5) ZrN, (6) CrgN, (
7) AIN, (8) Nitride such as HfN, (9) Zr
C, α0) HfC, αυSiC, (12Tac, α31
Z r C + α, 4) Carbide such as MnC and α'
JZn(L G*NxO,Q7)S+O2,Q8)WO
+(1!1lAI!03. A thin film (0.5 to 1.9 μm thick) of QφCuO oxide was formed. Thereafter, an insulating film containing phosphate and colloidal silica as main components was formed.

Then, EB irradiation was applied linearly at 10-tsuru intervals in the direction perpendicular to the rolling direction (EB irradiation conditions: acceleration voltage 60 KV, current 0.8 mA).
.

(beam diameter: 0.05), and then strain relief annealing was performed at 800° C. for 2 hours. The magnetic properties of the obtained product are shown in Table 2.

Table 2 B; Ion brating treatment C: Ion imblation treatment f C: 0.044%, Si: 3.38%, Mn:
0.072%, Se: 0.020%, Sb: 0
．． A hot rolled sheet containing 0.026% and Mo: 0.15% was uniformly annealed at 1000°C for 1 minute and then cold rolled twice with an intermediate annealing of 3 minutes at 950°C. ．．
The final cold rolled sheet was 18+mm thick. After that, primary recrystallization annealing was performed in wet hydrogen at 820°C, which also served as decarburization, and then an annealing separator containing A1□0s (70%) and MgO (30%) as main components was applied to the steel plate surface. After 50 hours at 850℃2
After recrystallization, purification annealing was performed in dry hydrogen at 1200° C. for 10 hours.

Then, after removing the oxide film by pickling, 3% liver and H20□
After chemically polishing in liquid to give a mirror finish, ion blating (FICD method) was performed to form (1) TiN, (2) N
bN.

(3) MozN, (4) WJ, (5) CoN, (6)
NiN, (7) Tic, (8) NbC, (91MozC
.

αIWC, αυCoC, α3NiC, α31VC, α4
) CrC, QS) A tensile thin film (target thickness of 1.0 μm) of AIC was formed. After that, an insulating film mainly composed of phosphate and colloidal silica was formed. Next, BB irradiation is performed linearly at 8-square intervals in the direction perpendicular to the rolling direction (acceleration voltage 50KV).
, current 0.9 mA, beam diameter 0, 1 m),
Strain relief annealing was then performed at 800° C. for 2 hours in nitrogen.

The magnetic properties of the obtained product are shown in Table 3.

Table 3 (Effects of the Invention) According to the first invention, it is possible to achieve a significant reduction in iron loss by compensating for the disadvantage of increased cost due to mirror finishing of the surface of the grain-oriented silicon steel plate that has been finish annealed. can. Further, according to the second invention, in addition to the above-described low iron loss, effective enhancement of insulation properties is realized.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the magnetic properties when an EB-treated material is annealed.

Claims (1)

[Claims] 1. After forming an insulating coating film mainly composed of phosphate and colloidal silica on a grain-oriented silicon steel sheet that has been finish annealed, EB irradiation is performed on the film in a direction transverse to the rolling direction. Method 2 for producing an ultra-low core loss unidirectional silicon steel sheet, which is characterized in that the surface oxides are removed from the finish annealed grain oriented silicon steel sheet, and then the steel sheet surface is polished to a center line average roughness. After finishing it to a mirror state with an Ra of 0.4μm or less,
Ti, Zr, Hf, V, Nb, T by CVD, ion plating or ion implantation.
a, Cr, Mo, W, Mn, Co, Ni, Al, B, S
i nitride and/or carbide and Al, Ni, Cu,
An ultra-thin tensile coating consisting of at least one selected from oxides of W, Si, and Zn is formed, and an insulating coating whose main components are phosphate and colloidal silica is formed. A method for producing an ultra-low iron loss unidirectional silicon steel sheet, comprising applying EB irradiation on the coating in a direction transverse to the rolling direction.