JPS621820A - Grain oriented silicon steel sheet having thermal stability and ultra-low iron loss - Google Patents

Abstract

PURPOSE:To provide a titled steel sheet which can sustain and provide an ultra-low iron loss characteristics even when subjected to a high-temp. treatment such as stress relief annealing by forming a tensile film under the conditions added with a fundamental improvement onto the surface of a grain oriented silicon steel sheet from which a non-metallic material is removed and which is subjected to finish annealing. CONSTITUTION:The non-metallic material is removed from the surface of the grain oriented silicon steel sheet subjected to finish annealing or further the surface if finished smooth. The tensile film 9 essentially consisting of >=1 kinds of the nitrides or carbides of Ti, Zr, Hf, V, Nb, Ta, Mn, Cr, Mo, W, Co, Ni, Al, B and Si is formed to 0.005-5mu by ion plating or ion implantation on such surface. The film 9 which is securely deposited onto the surface of the steel sheet 1 via a mixed phase 8 composed of the base iron of the sheet 1 and the film 9, is free from the deterioration in the characteristics even after the high- temp. treatment and has good adhesiveness and durability is thus obtd. A baked layer of an insulation coating may be formed on the film 9 in superposition thereon.

Description

[Detailed Description of the Invention] (Field of Industrial Application) In recent years, efforts have been made to improve the electrical and magnetic properties of unidirectional silicon steel sheets, and in particular to meet the extreme demands of reducing iron loss. The remarkable development efforts are gradually bearing fruit, but one serious problem associated with their implementation is that when unidirectional silicon steel sheets are processed and assembled and then subjected to so-called strain relief annealing, their characteristics deteriorate. It has been pointed out that the disadvantage is that it inevitably causes deterioration and limits its use.

In this specification, the following is related to the results of research and development that will lead to a new method that can advantageously meet the above requirements, regardless of whether or not it undergoes a high-temperature thermal history such as strain relief annealing. state

As is well known, unidirectional silicon steel sheets are products in which secondary recrystallized grains are highly concentrated in the (110) [:001), that is, Goss orientation, and are mainly used in transformers and other electrical appliances. The magnetic flux density (Bl.

It is required that the iron loss (represented by the Ltzs value) be high and the iron loss (represented by the Ltzs value) be low.

This unidirectional silicon steel sheet is manufactured through a wide variety of complicated processes, but numerous inventions and improvements have been made so far, and today products with a thickness of 0.30+ nm have magnetic properties of Blo 1.90T or higher. A+ysa 1. 051
'l/kg or less, and the magnetic properties of products with a plate thickness of 0.23mm are 8101, 89T or more, W17,'so O. 9
Unidirectional silicon steel sheets with ultra-low core loss of 0.01 Li/kg or less are being manufactured.

In particular, recently there has been a marked increase in the demand for reducing power loss as a top priority from the standpoint of energy conservation.・The "evaluation" (iron loss evaluation) system is becoming widespread.

(Prior Art) Under these circumstances, recently, the surface of a unidirectional silicon steel sheet after finish annealing is irradiated with a laser in a direction approximately 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 Publications No. 57-2252, 53419-1980, 26405-1985, and 26406-1986).

This magnetic domain refining technology is effective for transformer materials for stacked iron cores that are not subjected to strain relief annealing. There is a drawback that the laser irradiation effect disappears because microstrains are released by annealing and the magnetic domain width becomes wider.

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

However, this method of improving iron loss through mirror finishing cannot be adopted from a process perspective, as it does not contribute enough to reducing iron loss despite the significant increase in cost. Furthermore, it has not been adopted in current manufacturing processes because it has problems with adhesion to steel plates after being subjected to strain relief annealing at a high temperature of 600° C. or higher for a long time. Japanese Patent Publication No. 56-4150 also proposes a method in which a steel plate surface is mirror-finished and then an oxide-based ceramic thin film is vapor-deposited. However, this method cannot be used in actual manufacturing processes because the steel sheet and the ceramic layer will separate when subjected to high-temperature annealing at 600° C. or higher.

(Problems to be Solved by the Invention) The inventors have overcome the disadvantage of increased costs, especially from the perspective of today's development of energy-saving materials, by taking advantage of the effect of improving iron loss due to the mirror finish described above. We believe that it is essential to overcome the problems of adhesion and durability of the tensile coating layer, which does not deteriorate in properties even during high-temperature treatment.Based on this basic understanding, we have developed fundamental changes in the conditions for forming the tensile coating, especially in PVD processing. It is an object of the present invention to achieve an advantageous ultra-low iron loss by making improvements.

(Means for solving the problem) As a result of the above study, Ti, Zr, and Hf are applied to the surface of the finish-annealed unidirectional silicon steel sheet from which non-metallic substances have been removed or the smooth finished surface by further polishing. .

V, Nb, Ta, ! An, Cr, Mo, W
, Co, Ni, Al, B, and Si nitrides and/or carbides, and is strongly adhered to the surface of the steel plate through a mixed phase of these with the base iron. Thermal stability, ultra-low core loss unidirectional, characterized by comprising a 0.005 to 5 μm tension coating, or further comprising an insulating coated and baked layer deposited on top of the tension coating. He invented silicon steel sheets.

The explanation will proceed according to a specific experimental example that led to the success of this invention.

C: 0.046% by weight (hereinafter simply expressed as %), Si:
3.34%, Mn: 0.068%, Se: 0
．． 023%, sb: 0.025%, Mo: 0.
2. A silicon steel slab containing 0.025% was heated at 1360°C for 4 hours and then hot rolled. It was made into a hot-rolled sheet with a thickness of 0 mm.

After that, after homogenization annealing at 950℃ for 3 minutes,
It is cold rolled twice with an intermediate combustion of 0.2 minutes in between.
A final cold-rolled sheet with a thickness of 3 mm was obtained.

After that, after decarburization and next crystal annealing in a wet hydrogen atmosphere at 900°C, an annealing separator mainly composed of MgO is applied to the steel sheet surface, and secondary recrystallization annealing is performed at 850°C for 50 hours. Purification annealing was performed at 1200° C. in saturated hydrogen for 5 hours.

Thereafter, the steel plate was first pickled in H2SO solution at 80°C to remove the forsterite base film on the surface of the steel plate.

Next, chemical polishing was performed in a solution of 3% HF and 820□ to finish the surface of the steel plate into a mirror-like state with a center line average roughness of 0.1 μm.

Thereafter, using the ion plating apparatus shown in FIG. 1, TiN ion plating was performed on the polished surface to a film thickness of 0.5 μm.

In FIG. 1, 1 is a mirror-polished test substrate, 2 is a shutter, 3 is a crucible, 4 is an electron gun, 5 is a beam, 6 is an ionization electrode, 7 is a thermionic emission electrode, 8 is an N2.
C21 (2 or 0□, etc.) is a reaction gas inlet.

After the above ion plating, a coating treatment (formation of an insulating coated baked layer) with a coating liquid mainly composed of phosphate and colloidal silica was performed.
Strain relief annealing was performed at ℃ for 5 hours.

For comparison, 1 μm according to conventional known technology.
After applying steel plating treatment to the same polished surface, a coating baking treatment was also performed with a coating liquid whose main components were phosphate and colloidal silica, and then the coating was baked at 800℃ for 5 minutes.
Time-distortion annealing was performed.

Table 1 summarizes the experimental results of the magnetic properties and adhesion of the product.

As is clear from Table 1, currently manufactured by process,
After applying a coating treatment on the forsterite base film formed on the steel plate surface during final annealing, 8
Normally processed product (a) after strain relief annealing at 00℃ for 5 hours
The magnetic properties of BN) are 1.905T, and WB75o is 0.
Although the adhesion of the insulating film is approximately 87 W/kg, the forsterite film is removed by pickling after final annealing, and the surface is then chemically polished to a mirror finish. The magnetic properties of the products (products coated after copper plating) are B, 0 is 1.913T.
, L77so was slightly improved to about 0.741~/kg, but adhesion was poor.

However, according to the present invention, after final annealing, the forsterite film was removed, the surface was chemically polished to a mirror finish, and the product (C) was subjected to a similar coating process through ion plating, and the magnetic properties were B. O is 1.9
20'r, 111.7150 was 0.68 W/kg, which was not only a remarkable improvement in properties, but also extremely good adhesion of not only the tension coating but also the permanent coating and baking layer.

(Function) The improvement in magnetic properties and adhesion according to the present invention is achieved by mixing accelerated ions 1 and vapor deposited atoms a on the polished surface of a silicon steel plate serving as the substrate 1, as shown in the schematic diagram of FIG. The adhesion between the phase 8 and the tension coating 9 is greatly strengthened, and as a result, it acts on the surface of the strong silicon steel plate, achieving ultra-low iron loss unparalleled in the past. .

Since the function of plastic microstrain is not used here, there is no problem with thermal stability, and the electrical and magnetic properties are not affected by high-temperature thermal history such as strain relief annealing.

Here, the center line average roughness of the finished surface is Ra≦0.4μm
It is best to have a mirror state of Ra > 0.4 μm.
When , the surface is rough, so there is little hope for significant iron loss reduction.

Next, the thickness of the tension coating is suitable in the range of 0.005 to 5 μm; if it is less than 0.005 μm, it will not be able to contribute to providing the necessary tension, while if it exceeds 5 μm, the space factor and adhesion will deteriorate. disadvantages arise.

Strong adhesion on the mirror-like finished surface through the mixed phase of this tension coating is achieved by PVD (Physical
Vapor Deposition) or CV
D (Che-mical Vapor Deposit
ion).

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

The starting material is a conventionally known unidirectional silicon steel material composition, such as ■C: 0. Old ~ 0.050%, Si: 2.50 ~ 4.5
%, Mn: 0.0f ~ 0.2%, Mo
: 0.003 ~0. ] %, Sb: 0.0
Composition containing 0.05 to 0.2% and 0.005 to 0.05% of one or both of S or Se ■C: 0
．． Old ~0.08%, Si:2. Q~4.0%, Sol
Al: Q, 005-0.06%, S: 0.005
~0.05%, N: 0.001~0.01%, Sn:
0.01-0.5%, Cu: 0.01-0.3
%, Mn: Composition containing 0.01 to 0.2% ■C
:0.01~0.06%, Si:2.0~4.0%,
S: 0.005 to 0.05%, B: 0.0003
~0.020%, N: 0.001-0° old%,!
, 4n: Applicable to compositions containing 0.01 to 0.2%.Next, the hot rolled sheet is uniformly annealed at 800 to 1100°C and then cold rolled once to reduce @ final plate thickness. In the latter case, the initial rolling reduction is 5.
Approximately 0% to 80%, final reduction rate is 50% to 85%
The final cold rolled sheet thickness is approximately 0.15 mm to 0.35 mm.

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

After performing such treatment, an annealing separator is applied to the surface of the steel sheet. At this time, it is generally effective to prevent the formation of forsterite, which is essential for forming after final annealing, in order to simplify the subsequent mirror finishing of the steel sheet, so an MgO-based separator is used as the annealing separator. In addition to cases, especially Al2O, ZrO□, Tin, etc.
50% or more) is preferably mixed into 4gO.

After that, secondary recrystallization annealing is performed, but this step is (110)
This is done to sufficiently develop secondary recrystallized grains with <001> orientation, and is usually box annealed to immediately
This is done by raising the temperature above ℃ and maintaining it at that temperature.

In this case, in order to develop a highly uniform secondary recrystallized grain structure in the (110) <ooi> 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 is performed at 1100°C in saturated hydrogen.
It is necessary to perform annealing for 1 to 20 hours to achieve purification of the steel plate.

After this purification annealing, nonmetallic substances such as forsterite coatings or oxide coatings on the surface of the steel sheet are removed by known chemical removal methods such as pickling, mechanical removal methods such as cutting and grinding, or a combination thereof.

After this oxide removal treatment, if necessary, the steel plate surface is polished to a mirror finish (centerline average roughness 0.4 μm or less).

After removing non-metallic substances or mirror polishing, Ti, Zr, Hf, V, Nb, Ta, M are removed by CVD, ion plating or ion implantation E7.
n, Cr.

At least one ultra-thin tensile coating is formed which mainly consists of at least one selected from Mo, W, Co, Ni, Al, B, and Si nitrides and/or carbides.

Moreover, it is effective to form this ultra-thin tension coating with a thickness of about 0.005 to 5 μm. A coating with a thickness of 0.005 μm or less has a small tension effect, so it has little effect on reducing iron loss, and if it is 5 μm or more, the film thickness becomes thick and the space factor decreases, which is not economical, so the thickness of the tension coating is 0. .0
05 to 5 μm is suitable.

Furthermore, an insulating film containing colloidal silica or phosphate and colloidal silica as main components is applied and baked on the ultra-thin tensile film produced in this way, and then subjected to long-term strain relief annealing at a high temperature of 600°C or higher. Naturally, it is necessary for transformers to have good adhesion and no deterioration of magnetic properties even when exposed to heat, and the formation of this insulating baked layer and the subsequent strain relief annealing method can be done using conventionally known methods. May be used.

In addition, improvements in magnetostrictive compression properties can also be achieved with the present invention.

(Example) Example I C: 0.047%, Si: 3.4%, Mn: 0.0
62%, Mo: 0.025%, Se: 0.02
2%, Sb: 0.020%.
After uniform annealing at 00°C for 3 minutes, cold rolling was performed twice with intermediate annealing at 950°C to obtain a final cold-rolled sheet with a thickness of 0.23mm.

After decarburization annealing in wet hydrogen at 820°C, Mg is deposited on the surface of the steel sheet.
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 saturated hydrogen at 1200° C. for 8 hours.

After that, after removing the forsterite film by pickling, 3
It was chemically polished in %HF and H,0□ solution to give a mirror finish.

After that, using the apparatus shown in Fig. 1, ion plating was performed for 3 minutes at an ionization voltage of 10 KV to form a TiN film with a thickness of 0.5 μm.
A tension film was formed.

Next, an insulating coated and baked layer containing phosphate and colloidal silica as main components was formed, and then strain relief annealing was performed at 800° C. for 2 hours.

The magnetic properties and adhesion of the product at that time were as follows.

Magnetic properties: B+o=1.91T, W+t7so
=0.6911/kg Adhesion: 18 in order of bending radius 30
Even when bent by 0°, it could not be peeled off, and the adhesion was good.

Example 2 C: 0.062%, Si: 3.3%, Mn: 0.0
90%, Al: 0.025%, S: 0.030%,
A hot rolled sheet containing N: 0.0068% was heated to 1150
After equalization annealing for 3 minutes at ℃, rapid cooling treatment was performed, and then 30
Warm rolling was performed at 0° C. to obtain a final cold-rolled sheet with a thickness of 0.20 mm.

After decarburization annealing in wet hydrogen at 850°C, the surface is coated with MgO.
After applying an annealing separator mainly composed of
After secondary recrystallization by raising the temperature to 150°C at a rate of 8°C/hr, purification annealing was performed in hydrogen hydrogen at 1200°C for 8 hours.Then, the forsterite film was removed by pickling, and then 3% It was chemically polished in HF and 820□ solution to give it a mirror finish.

After that, nitrogen ions were implanted for 3 minutes at an ion acceleration voltage of 49 KV using the ion implantation method to form a film with a thickness of 0.2
After forming an ultra-thin tension film of SiN at μm, and then forming an insulating coating and baking layer mainly composed of phosphate and colloidal silica, strain relief annealing was performed at 800°C for 2 hours. .

The magnetic properties and adhesion of the product at that time were as follows.

Magnetic properties: B+o=1.93T, W+tzso
=0.68W/kg Adhesion: 18 at bending radius 30mm
Even when bent by 0°, it could not be peeled off, and the adhesion was good.

Example 3 C: 0.044%, Si: 3.45%, Mn: 0.
066%, Se: 0.023%, Sb: 0.0
A unidirectional silicon steel sheet containing MO: 25% and MO: 0.026% was heated at 1360° C. for 4 hours, and then hot rolled into a hot rolled sheet having a thickness of 2.20 aun. After that 90
After uniform annealing at 0°C for 3 minutes, cold rolling was performed twice with an intermediate annealing at 950°C for 3 minutes to obtain a 0.23+ nm
A thick final cold-rolled sheet was obtained.

After that, after performing primary recrystallization annealing that also serves as decarburization in wet hydrogen at 820°C, A1□03 (60%), Mg0 (30
%).

After applying an annealing separator mainly composed of 2rO□ (5%) and TiO□ (5%), secondary recrystallization annealing was performed at 850°C for 50 hours, followed by purification in dry H2 gas at 1200°C for 8 hours. Annealing was performed.

After removing oxides on the steel plate surface by light pickling,
The surface of the steel plate was polished to a mirror finish by electrolytic polishing.

Then (a) magnetron sputtering method, (5) [
B (Electron Beam) + RF (Rad)
io Frequency) method, (C) HCD (HpH
ow Cathode Discharge) and (
d) After forming a TiN tension film using an ion plating device using the MultiArc method, at 800°C
The product was then subjected to strain relief annealing for 3 hours. Table 2 shows the magnetic property values of the product at that time and the X-ray diffraction results of the TiN coating.
Shown below.

Table 2 As is clear from Table 2, the magnetic properties of TiN thin films formed by four types of ion plating methods were 81
0 is 1.91 to 1.92751117/So is 0.69
~0.72 W/kg, which is extremely good. In addition, the X-ray diffraction results of the thin film on the surface are (a) and (d)
), only TiN peaks were detected; under condition (a), TiN peaks were the main one, but some Ti peaks were detected; and under condition (C), TiN peaks were the main one, although Ti2N and TiN peaks were detected slightly. , peaks of this magnitude for materials other than TiN do not have a significant effect on magnetic properties. The adhesion of all the products at this time was good, with no peeling even when bent by 180° with a bending radius of 25n+m or less.

Example 4 C: 0.042%, Si: 3.32%, Mn: 0.
062%, Mo: 0.022%, Se: 0.0
A hot-rolled sheet containing 21% and Sb: 0.025% was homogenized at 900°C for 3 minutes, then cold-rolled 21 times with intermediate annealing at 950°C for 3 minutes. .2
A final cold-rolled sheet with a thickness of 3 mm was obtained.

After that, after performing primary recrystallization annealing that also serves as decarburization in wet hydrogen at 820°C, the surface of the steel plate is coated with Al2O3 (70%).
After applying an annealing separator consisting of Mg0 (25%) and ZrO□ (5%), secondary recrystallization annealing was performed at 850°C for 50 hours, followed by purification annealing at 1200°C for 7 hours in dry hydrogen. provided.

After that, (a) the oxide film on the surface of the steel plate was removed by pickling, and (b) the oxide film was removed by pickling and then electrolytically polished to give a mirror finish with a center line average roughness of 0.04 μm or less. . Later, by ion plating, 1.2
A μm thick TiN film was formed.

Thereafter, one part was coated with a coating film mainly composed of phosphate and colloidal silica, and then subjected to strain relief annealing at 800° C. for 5 hours to produce a product. The magnetic properties of the product at that time are shown in Table 3 in comparison with the current product having a forsterite coating.

The current product undergoes primary recrystallization annealing that also serves as decarburization in wet hydrogen at 820°C, and then coats the surface of the steel plate with an annealing separator containing MgO as the main component. Next, recrystallization annealing was performed, followed by purification annealing at 1200° C. for 7 hours in dry hydrogen. Thereafter, the whole stellite film was baked and then subjected to strain relief annealing at 800° C. for 5 hours to produce a product.

In addition, the adhesion of the product at this time is based on the bending radius of 25.
mm or less, and there was no peeling even when bent by 180°, which was good.

Table 3 Example 5 C: 0.043%, Si: 3.32%, Mn:
0.066%.

Silicon steel hot rolled sheet containing Se: 0.019%, Sb: 0.025% and MO2 0.023% (2,
0mm thick) with intermediate annealing for 3 minutes at 950℃.
The sample was cold-rolled twice to obtain a cold-rolled plate with a thickness of 0.23 mm. After that, primary recrystallization annealing was performed at 820°C for 3 minutes for decarburization, and then Al2O3 (60%>, Mg0(
35%), ZrO□ (3%), and TI[]2 (2%) were applied in the form of a slurry.

After that, secondary recrystallization annealing was performed at 850°C for 50 hours, and then purification annealing was performed at 1200°C for 6 hours with dry hydrogen. Surface oxides were removed by pickling, and the surface of the steel plate was polished by electrolytic polishing. was made into a mirror state. Then CVD
(no mark in Table 4), ion plating (○ mark in Table 4), and ion implantation (Δ mark in Table 4)
After forming various thin films (approximately 0.67 to 1.5 μm in thickness), a coating film containing phosphate and colloidal silica as main components was baked and then subjected to strain relief annealing at 800° C. for 5 hours. Table 4 summarizes the magnetic properties of the products at that time.

In addition, the adhesion of the product at this time is based on the bending radius of 25.
+nm or less and no peeling occurred after 180° bending.

Example 6 C: 0.043%, Si: 3.37%, Mn:
0.063%, Mo: 0.025%, Se
A hot rolled sheet containing Sb: 0.022% and Sb: 0.025% was prepared.

This hot-rolled sheet was homogenized at 900°C for 3 minutes and then heated to 950°C.
Cold rolling was performed twice with intermediate annealing at 0.2 °C.
A final cold-rolled sheet with a thickness of 3 mm was obtained.

After that, after decarburization annealing in wet hydrogen at 820℃, A
"203 (75%), Mg mouth (20%), Zr02
After applying an annealing separator mainly composed of (5%) 850
A secondary recrystallization annealing at 1200° C. for 50 hours and a purification annealing in H 2 at 1200° C. for 8 hours were performed.

Thereafter, the oxide film on the surface of the steel plate was removed by pickling, and then chemically polished in 3% HF (!:8202 solution) to give a mirror finish.Then, CVD (no mark in Table 5) ion plating (○ in Table 5) (marked) and ion implantation (marked Δ in Table 5) to form various compound thin films of 0.7
It was formed to have a thickness of ~0.9 μm.

Thereafter, the surface of the sample subjected to these treatments was subjected to a baking treatment to form an insulating coating mainly composed of phosphate and colloidal silica, and then strain relief annealing was performed at 800° C. for 2 hours.

The magnetic properties and magnetostrictive compressive stress properties of the product at that time,
(Magnetostriction values λpp when the compressive stress σ is 0.4 and 0.6 ktr/mm2) are summarized in Table 5.

Example 7 C: 0.056%, Si: 3.29%, Mn + 0.
078%, Al: 0.025%, S: 0.030%, C
u: 0.1%.

144 unidirectional silicon steel containing Sn: 0.05%
After heating at 0°C for 5 hours, it is hot rolled to 1.6-2.7
It was made into a hot-rolled plate with a thickness of mm.

Thereafter, uniform annealing was performed at 1100° C. for 3 minutes, followed by rapid cooling. After that, it was warm rolled at 350°C to 0.2
Q, 0.23, 0.27 and (], The final cold-rolled sheet had a thickness of 30.

After that, primary recrystallization annealing was performed in wet hydrogen at 850°C, which also served as decarburization.
%).

TlO□ (5%), Zr03 (5%) After applying an annealing separator of 5%, after secondary recrystallization annealing at 850 °C for 50 hours, 1
Purification annealing was performed at 200°C for 5 hours in dry H2 gas.

Thereafter, the oxide film on the surface of the steel plate was removed by pickling, and then electropolishing was performed to finish the surface of the steel plate to a mirror finish.

After that, using PVD (ion plating device), C
After forming a thin film of r2N and baking an insulating film mainly composed of phosphate and colloidal silica,
Strain relief annealing was performed at 0°C for 3 hours.

At that time, the thickness side magnetic properties of the product, the film thickness of Cr and N thin films, and the compressive stress properties of magnetostriction (compressive capacity σ is 0.4 kg/
The values of magnetostriction λ at mff12 and 0.6 kg/1nn2 are summarized in Table 66.

Example 8 (a) C: 0.042%, Si: 3.36%, Mn
+0.062%, Mo: 0.024%, Se
: 0.021%, Sb: 0.025% (b) C:
0.056%, Si: 3.36%, Mn: 0.06
8%, At: 0.026%, S: 0.029%
, N: 0.0069%.

Hot rolled sheets containing Cu: 0.1% and Sn: 0.05% were prepared.

First, the hot-rolled sheet (a) was uniformly annealed at 900° C. for 3 minutes and then cold-rolled twice with intermediate annealing at 950° C. to obtain a final cold-rolled sheet having a thickness of 0.20 at+n.

On the other hand, the hot-rolled sheets of (2) were uniformly annealed at 1080°C for 3 minutes, then rapidly cooled, and then warm rolled at 300°C.
．． A final cold-rolled sheet with a thickness of 20 mm was obtained.

The subsequent cold-rolled sheet was also decarburized and annealed in wet hydrogen at 830°C, and Al2O3 (75%) and Mg0 were added to the surface of the steel sheet.
(20℃, after applying an annealing separator mainly composed of ZrO Purification annealing in hydrogen gas, sample made from material (b) at 850°C
After secondary recrystallization was performed by raising the temperature from 100° C. to 1050° C. at a rate of 5° C./hr, purification annealing was performed at 1200° C. for 8 hours in hydrogen hydroxide.

After that, the oxide film was removed by pickling, and then 3% HF
and chemically polished in 1120□ solution to a mirror finish.

After that, using a CVD device, 1t"'C (i>TiCl4 and H
2 and N2 (7) mixed gas to form a thin film of TiN, (ii)
TiC1, H2, N2 and CH4 mixed gas
(CN) thin film and (iii) TIC14, H2 and N
A thin film of TiC was formed using a mixed gas of 2 and CH, each having a thickness of 0.7 μm. Also, using ion plating and ion implantation equipment (i
v) Ti(CN) and (v) Tic from 0.7 to 0.
A thin film with a thickness of 9 μm was formed.

Thereafter, the surface of the sample subjected to these treatments was subjected to a baking treatment to form an insulating coating mainly composed of phosphate and colloidal silica, and then strain relief annealing was performed at 800° C. for 2 hours.

The magnetic properties and magnetostrictive compressive stress properties of the product at that time (
Table 7 shows the values of magnetostriction λ and P under compressive stress σ of 0.4 and 0.6 kg/mm'.

Example 9 C: 0.043%, Si: 3.42%, Mll: 0
．． 069%, Se: 0.021%.

3b: After heating unidirectional silicon steel containing Q, 025%, Mo + 0.025% at 1400 ° C. for 3 hours,
It was hot rolled into a hot rolled sheet of 1.8 to 2.7 n+m. After that, after uniform annealing at 900°C for 3 minutes, cold rolling was performed twice with intermediate annealing at 950°C for 3 minutes to obtain a 0.20
．． The final cold rolled sheets were 0.23, 0.27+++m and 0.30+nm thick.

After that, after performing primary recrystallization annealing that also serves as decarburization in wet hydrogen at 830°C, MgO (20%), A1□03 (70%
).

After applying an annealing separator of TiO, (5%) and ZrO□ (5%), secondary recrystallization annealing was performed at 850°C for 50 hours.
Purification annealing was performed in dry H2 gas at 1200°C for 5 hours. Thereafter, oxides on the surface of the steel plate were removed by light pickling, and then electrolytic polishing was performed to finish the surface of the steel plate to a mirror finish.

After that, a thin film of TiN was formed using a PVD device (ion plating device), and an insulating coating mainly composed of phosphate and colloidal silica was baked.
Strain relief annealing was performed at 00°C for 3 hours. The thickness side magnetic properties of the product at that time, the film thickness of the TiN thin film, and the compressive stress characteristics of magnetostriction (the value of magnetostriction λ1 when the compressive stress σ is 0.4 kg/mm" and 0.6 kg/mm") ) in Table 8
Shown below.

(Effects of the Invention) According to each of the first to fourth inventions, when a unidirectional silicon steel sheet is used that undergoes high-temperature thermal history such as strain relief annealing, there is no performance deterioration resulting from high-temperature treatment. A unidirectional silicon steel sheet with excellent thermal stability is provided, and by the method of the fifth invention, the above-mentioned outstanding ultra-low iron loss property can be maintained even after high-temperature treatment. A unidirectional silicon steel plate can be appropriately obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of ion plating, and FIG. 2 is an explanatory diagram showing deposition behavior of accelerated ions and vapor deposited atoms. Figure 1 (Fipmeft) Figure 2 1... Katana Roshi, Ion

Claims (1)

[Claims] 1. Ti, Zr, Hf, V, Nb,
It mainly consists of at least one kind selected from nitrides and/or carbides of Ta, Mn, Cr, Mo, W, Co, Ni, Al, B, and Si, and forms a surface of the steel sheet through a mixed phase with the base iron. and at least one layer of 0.
A thermally stable, ultra-low iron loss unidirectional silicon steel sheet characterized by having a tensile coating of 0.005 to 5 μm. 2. After removing the non-metallic substances on the surface of the unidirectional silicon steel plate that has been finish annealed, the T
i, Zr, Hf, V, Nb, Ta, Mn, Cr, Mo,
The at least one material is mainly composed of at least one kind selected from nitrides and/or carbides of W, Co, Ni, Al, B, and Si, and is firmly adhered to the surface of the steel sheet through a mixed phase of these with the base iron. A thermally stable, ultra-low iron loss unidirectional silicon steel sheet, characterized by having one layer of a tensile coating of 0.005 to 5 μm. 3. Ti, Zr, Hf, V, Nb, T
It mainly consists of at least one kind selected from nitrides and/or carbides of a, Mn, Cr, Mo, W, Co, Ni, Al, B and Si, and forms a surface of the steel sheet through a mixed phase with the base iron. At least one layer of O.
1. A thermally stable, ultra-low iron loss unidirectional silicon steel sheet comprising a tensile coating of 0.005 to 5 μm, together with an insulating coated and baked layer overlaid on the tensile coating. 4. After removing the non-metallic substances on the surface of the unidirectional silicon steel sheet that has been finish annealed, polish the surface to make it smooth.
i, Zr, Hf, V, Nb, Ta, Mn, Cr, Mo,
The at least one material is mainly composed of at least one kind selected from nitrides and/or carbides of W, Co, Ni, Al, B, and Si, and is firmly adhered to the surface of the steel sheet through a mixed phase of these with the base iron. Thermal stability, ultra-low iron loss unidirectionality characterized by having one layer of 0.005 to 5 μm tension coating, and having an insulating coated and baked layer deposited on top of this tension coating. Silicon steel plate. 5. 1 to the hot-rolled plate obtained by hot-rolling the silicon-containing slab.
The steel plate is cold-rolled twice with intermediate annealing in between to achieve the final thickness, then subjected to decarburization and primary recrystallization annealing, and then an annealing separator mainly composed of MgO is applied to the steel plate surface. a step of forming a forsterite base film in accordance with a conventional method in which the forsterite base film is then subjected to final annealing; a step of removing the forsterite base film and then polishing the surface to give it a smooth finish; , Ti, Zr, Hf, V, Nb, Ta, Mn, Cr by ion plating or ion implantation.
, Mo, W, Co, Ni, Al, B, and Si nitride and/or carbide. A method for manufacturing an ultra-low core loss unidirectional silicon steel sheet with excellent thermal stability in magnetic properties.