JPS6324018A - Production of extra-low iron loss grain oriented silicon steel sheet - Google Patents

Abstract

PURPOSE:To produce an extra-low iron loss silicon steel sheet having excellent adhesiveness of a film by removing the oxide on the surface of a grain oriented silicon steel sheet subjected to finish annealing, then polishing the surface to a specular surface and depositing and implanting the ions of the surface film forming components, thereby making dry plating. CONSTITUTION:The oxide on the surface of the grain oriented silicon steel sheet subjected to finish annealing is removed by pickling and the surface is finished to the specular surface of <=0.4mum center line average height Ra. The surface is then coated by dry plating with >=1 kinds among the nitride or carbide of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, Co, Ni, Mn, Al, B, and Si or the oxide of Cr, Al, Ni, Cu, W, Si Ti, Sn, Fe, Zr, Ta, Ce, and Zn. The deposition of the film to the steel sheet is executed by evaporating or ionizing the metal or metalloid to deposit the vapor or ions thereof onto the steel sheet and subjecting the nonmetal element to ion implantation. The extra-low iron loss grain oriented silicon steel sheet which is decreased in the iron loss and is improved in the film adhesiveness is obtd. by the above-mentioned method.

Description

[Detailed Description of the Invention] (Field of Industrial Application) In recent years, there has been a remarkable effort to improve the electrical and magnetic properties of unidirectional silicon steel sheets, and in particular to meet the extreme demands of reducing iron loss. Our 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 properties deteriorate. It has been pointed out that there are disadvantages in that this inevitably involves the use of treasury materials and restrictions on how they can be used.

This specification introduces 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. I will explain.

As is well known, unidirectional silicon@plate is a product in which secondary recrystallized grains are highly integrated in the (110) <001>, or Goss, orientation, and is mainly used in transformers and other electrical appliances. It is used as the iron core of equipment, and the product's magnetic flux density (B,.

It is required that the iron loss (represented by W17/S) be high and the iron loss (represented by W17/S) 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 a product with a thickness of 0.30u+ has magnetic properties of 8.
101.90T or more, 1,7. . The magnetic properties of products with a weight of 1.05 匈/kg or less and a plate thickness of 0.23 mm are BIGl.
, 89T or higher, WM7/S. Unidirectional silicon steel sheets with ultra-low core loss of 0.90 W/kg or less are being manufactured.

Particularly recently, there has been a marked increase in demand for power loss reduction features 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 sheet after final 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 (see Japanese Patent Publication No. 57-2252, Japanese Patent Publication No. 57-53419, Japanese Patent Publication No. 58-26405, 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,
There is a drawback that the local minute strain introduced by laser irradiation is released by annealing and the magnetic domain width becomes wider, so that the laser irradiation effect disappears.

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

However, this method of improving iron loss through mirror finishing cannot be adopted from a process perspective, as it does not make a sufficient contribution to reducing iron loss despite the significant cost increase. Due to problems with adhesion after applying the adhesive, it has not been adopted in the current second manufacturing process.

(Problems to be Solved by the Invention) Therefore, a method for manufacturing a unidirectional silicon steel sheet in which a surface coating is formed by dry plating on the surface of a unidirectional silicon steel sheet with a mirror finish to reduce iron loss. It is an object of the present invention to further improve the adhesion of the surface coating and reduce iron loss.

(Means for Solving the Problem) The inventors believe that an increase in internal stress within the coating formed on a unidirectional silicon steel sheet that has undergone finish annealing increases the tension acting on the base material, leading to iron loss. Increasing the ionization rate of the reactive gas during dry plating promotes ion implantation of reactive gas atoms into the coating crystal, increasing lattice strain and increasing internal stress within the coating. These findings led to this invention.

That is, this invention involves removing oxides from the surface of a unidirectional silicon steel plate that has undergone finish annealing, and then polishing the steel plate surface to a mirror surface with a centerline average roughness Ra of 0.4 μm or less. T by dry plating
i, Zr + Hf + V, Nb, Ta
.

Cr + Mo + Col Ni + Mnt AI
+8 and Si nitride and/or carbide or C
r, AI, Ni, Cu.

W + Si + Ti + Sn + Fe + Zr
+ Ta + In a method for producing a grain-oriented silicon steel sheet which is coated with a surface coating mainly consisting of at least one selected from Ce and Zn oxides, during the dry plating, the components of the surface coating are Production of ultra-low iron (unidirectional) silicon steel sheet characterized by evaporating and ionizing metal or metalloid elements and ion-implanting non-metallic elements among the surface coating components onto the surface of the steel sheet. It's a method.

Reactive gas (non-metallic elements) in ion blating
The ionization rate was estimated to be 30% at most, but it becomes almost 100% when ions are implanted.

As the ionization rate increases, internal stress within the coating increases, tension on the steel plate increases, and iron loss decreases. At the same time, as the ionization rate of the nonmetallic element increases, activation of the surface of the base material by ions is promoted, and the adhesion of the coating becomes even stronger (see, for example, Japanese Patent Laid-Open No. 15967/1983).

Here, the center line average roughness Ra of the surface of the unidirectional silicon steel sheet before the surface coating was formed was limited to 0.4 μm or less because
This is because if Ra exceeds 0.4 μm, the surface will be rough and a sufficient reduction in iron loss cannot be expected.

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

The starting material has conventionally known unidirectional silicon steel material components, such as ■C: 0.01-0.05%, Si: 2.0-0.
4.0%, Mn: 0.01-0.2%, Mo:
0.003-0.1%, Sb: 0.005-0.
2%, one or two types of S or Se, 0.0
Composition containing 05-0.05% ■C: 0.01-0.
08%, Si: 2.0-4.0%, S: 0
．． 005 ~ 0.05%, N: 0.001 ~ 0
．． 01%, Sol Al: 0.01~0.06χ
, Sn: 0.01-0.5%, Cu:
0.01-0.3%, Mn: 0.01-0.
Composition ■C containing 2%: 0.01-0.06%,
Si: 2.0 to 4.0%, S: 0.0
05-0.05%, B: 0.0003-0.0
004%, N: 0.001-0.01%, Mn:
Composition containing 0.01-0.2% ■C: 0.01-0.06χ, Si: 2.0-4
．． 0%, Mn: 0.01 to 0.2% S or Se, or both o, oos to o
, OSX-containing compositions, etc. Next, the hot-rolled sheet is subjected to uniform annealing at 800 to 1100°C and then cold-rolled once to achieve the final thickness, or, Usually, a two-step cold rolling method is used in which intermediate annealing at 850°C to 1050°C is followed by further cold rolling. 8
At about 5%, the final cold-rolled plate thickness is from 0.15-m to 0.35 tm.

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.

After that, the steel plate surface Ni Ajl! zO++ZrO or Tt
Apply an annealing separation agent whose main component is Oz+1'1gO or the like. The present invention is applicable regardless of whether forsterite is formed or not. In order to prevent the formation of a forsterite film after final annealing, it is necessary to increase the content of an inert annealing separator such as A 6203.

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 (2 highly aligned in the 1101<001> direction)
To develop the next recrystallized grain structure, heat at 820°C.
It is more advantageous to carry out holding annealing at a low temperature of 0.000C, and alternatively heat removal annealing at a temperature increase rate of 0.5 to 15C/h may also be used.

Purification annealing after secondary recrystallization annealing is performed at 1000°C in saturated hydrogen.
It is necessary to perform annealing for 1 to 20 hours to achieve purification of the steel plate.

Next, in the present invention, after purification annealing, the oxide film on the surface of the steel sheet is removed using a strong acid such as sulfuric acid, nitric acid, or hydrofluoric acid. Further, this oxide removal may be performed by mechanical grinding.

After this oxide removal treatment, chemical polishing or electrolytic polishing
Alternatively, the surface of the steel plate can be polished to a mirror finish using a conventional method such as mechanical polishing using puff polishing, that is, the center line average roughness Ra is 0.4.
Finished to below μm.

(Function) Next, we will discuss specific experiments that led to the success of this invention.

Ti + Cr + A1 was applied to a unidirectional silicon steel plate mirror-finished to a center line average roughness Ra = 0.2 μm by the ion blating method using hollow cathode discharge.
and Si carbides, nitrides, and oxides of 1 each
．． It was coated to a thickness of 0 μm. In addition to ion implantation, a reactive gas was also introduced for comparison.

The apparatus used in this experiment is shown in Figure 1. In the figure, 1 is a hollow cathode gun, 2 is an evaporation power source, 3 is a focusing coil, and 4
is an evaporation source such as a water-cooled copper crucible, 5 is a steel plate, 6 is a heater, 7 is a bias power source, and 8 is an ion source.

The experimental conditions were: electron beam output 40V, 500V
A. Applied voltage to steel plate: 100V and ambient temperature =
The temperature is 300°C.

Tables 1 to 3 show the iron loss reduction 41 due to the formation of each coating. The product was identified by X-ray diffraction.

From the table, it can be seen that ion implantation provides a greater reduction in core loss than normal reaction gas introduction.

Furthermore, the surface of the film produced by ion implantation was examined using a scanning electron microscope (S) in an adhesion test by immersion in liquid N2.
No peeling was observed in the EM) observation. However, peeling was visually observed in the film produced with 4 injections of the usual reaction gas. Therefore, it has become clear that by using ion implantation, it is possible to obtain a film with stronger adhesion than when using normal reactive gas introduction.

The above experimental results are based on Ti, Cr, AI, S
Although the tension coating made of i carbide, nitride, and oxide has been exclusively described, the tension coating can also be made of Zr, Hf, etc.
.

V + Nb + Ta + Mo + Co + N
t + nitrides and/or carbides of Mn and B and Ni, Cu, W, Sn.

Even when the oxide is mainly composed of at least one kind selected from oxides of Fe, Zr + Ta, Ce and Zn, Ti, Cr, Al, S
The carbides, nitrides, and oxides of i have substantially the same effects as those described above, and all of them are suitable for the purpose of the present invention.

(Example) Practical flaming C: 0.046%, Si: 3.44%, Mn:
0.069%, Mo: 0.020%, Se:
A hot rolled sheet having a composition containing 0.020% and Sb: 0.025% was uniformly annealed at 900°C for 3 minutes and then cold rolled twice with intermediate annealing at 950°C. A final cold-rolled sheet with a thickness of 0.23 mm was obtained.

After that, after primary recrystallization annealing that also served as decarburization annealing in wet hydrogen at 820°C, the surface of the steel plate had 81203 (70%), M
After applying an annealing separator containing g0 (30%) as a main component, secondary recrystallization annealing was performed at 850°C for 50 hours, followed by purification annealing at 1200°C for 8 hours in saturated hydrogen.

After that, the oxide film was removed by pickling, and then electrolytically polished to a mirror finish.

Thereafter, a 0.5 μm thick TiN layer was formed using a high frequency excited ion blating device equipped with an ion source. The electron beam output was 10 KV and 200 mA, the high frequency excitation output was 800, the bias voltage was 500 V, and the ambient temperature was 300°C. The amount of N9 ions generated from the ion source was 6 Xl014 ions/cm2-s.

The magnetic properties of the obtained silicon steel plate were W+7/S. =0.6
4W/kg, B+o=1.937. Also, no peeling was observed in the adhesion test using 10 x mφ bending.
0.071%, 812 70.024%, S
: 0.026%, N: 0.0069%, Cu
A hot rolled sheet having a composition containing Sn: 0.1% and Sn: 0.05% was uniformly annealed at 1150°C for 3 minutes and then rapidly cooled, and then warm rolled at 300°C to The final cold-rolled sheet had a thickness of .2 (bm).

After decarburization annealing in wet hydrogen at 850°C, the surface has A'
After applying an annealing separator mainly composed of zo3 (80%) and MgO (20%), the temperature was raised from 850°C to 1150°C at a rate of 8°C/h for secondary recrystallization, and then soft hydrogen Purification annealing was performed at 1200° C. for 8 hours.

After that, the oxide film was removed by mechanical polishing, and then 3%
It was chemically polished in HF and I+ 202 liquid to give it a mirror finish.

Thereafter, a 1.0 μm thick layer of Sin was deposited on the surface using a hollow cathode discharge ion blating device equipped with an ion source.

The output of the electron beam was 500 A and 40 V, the ambient temperature was 300° C., and the voltage applied to the steel plate was 100 μm.

Also, O゛ ions generated from the ion source 5. OXl0I5
ions/Cm2.

The magnetic properties of the obtained silicon steel sheet were 1.7. .・0.6g, B1゜・l, 94T, interlayer resistance is 10
The resistance was good at 0Ω·cm/piece. Further, no peeling was observed in the adhesion test using Ionφ bending.

Secret blood source C: 0.044%, Si: 3.38%, Mn:
0.062%, Mo: 0.025%, Se:
A hot rolled sheet having a composition containing 0.024% and Sb: 0.025% was uniformly annealed at 900°C for 3 minutes and then cold rolled twice with intermediate annealing at 950°C. A final cold-rolled sheet with a thickness of 0.20-m was obtained.

After that, after decarburization annealing in wet hydrogen at 820℃, A
'z(h(70%), MgO(25%), Zn
After applying an annealing separator mainly composed of O (4%) ITIOZ (1%), secondary recrystallization annealing was performed at 850°C for 50 hours, and purification annealing was performed at 1180°C for 10 hours in dry hydrogen.

After that, after removing the oxide film on the steel plate surface by pickling, 3%
Chemically polished in HF(!:H2O□ solution) to give a mirror finish.

Thereafter, AIN and ZrC were mixed with HfN at an ambient temperature of 200 °C by an activated ion blating device using a thermionic filament equipped with an ion source.

NbN, SiC, HfC and ZnO at an ambient temperature of 300°C, ZrN + MnzN, MoJ +
VN + Cr7C, NiC, NbC.

ZrO, Fe30a and ZrO at an ambient temperature of 400℃
, Bn, 5iJ4+ TiCl5iOz and A
1z03 was deposited on the surface of each steel plate at an ambient temperature of 500°C.

The output of the electron beam evaporation source was 20 KVA, the thermionic filament current was 2 A, and the voltage applied to the steel plate was 1.
It was OKV. Also, maximum 2X 10I from the ion source
Sasseta generates ions of 6 ions/cm2・s.

After that, a coating treatment containing phosphate and colloidal silica as the main components was performed. Table 4 shows the magnetic properties of the obtained steel plate.
Shown below.

Table 4 Processing conditions Magnetic property coating
Savory (”C) B,. (T) W+tzs. (Vow/kg
)(1) BN (0.8μm thickness) 50
0 1.92 0.63(2) 5iz
N+ (0.8I'm thickness) 500 1
．． 94 0.64(3) ZrN (0.9μ
m thickness) 400 1.91 0.
62(4) AIN (0.8μm thickness)
200 1.92 0.64 (5)
HfN (1.0/1m thickness) 300 1.
92 0.62(6) NbN (1,01!
m thickness) 300 1.92 0
．． 65(7) MnzN (1.0μm thickness') 40
0 1.91 0.64 (8) MozN (1,0
μm thickness) 400 1.92 0.63 (9
) Vn (1.0 μm thickness) 400
1.93 0.62 (10) Tic (
0.88a thickness) 500 1.920.62 (11)
SiC (0.6μm thickness) 300
1.92 0.63(12) ZrC(0,7
pm thickness) 200 1.91 0
．． 63 (13) CrtC+ (1,0/Jm thickness)
400 1.92 0.63 (14
) HfC (1.0μm thickness) 300 1.920.61
(15) NiC (1.01Jm thick) 40
0 1.91 0.64(16) NbC
(1.0 μm thickness) 400 1.920.62 (Effects of the invention) According to the present invention, in a method for manufacturing an ultra-low core loss unidirectional silicon steel sheet using dry plating, further reduction of core loss and coating film can be achieved. It is possible to achieve improved adhesion.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the apparatus used in the experiment. 1... Hollow cathode gun 2... Evaporation power source 3... Focusing coil 4...
・Evaporation source 5... Steel plate 6... Heater
7...Bias power supply 8...Ion source

Claims (1)

[Scope of Claims] 1. Oxides on the surface of a unidirectional silicon steel plate that has undergone finish annealing are removed, and then polished to a mirror finish with a center line average roughness Ra of 0.4 μm or less. After that, Ti, Zr, Hf,
V, Nb, Ta, Cr, Mo, Co, Ni, Mn, Al
, B and Si nitride and/or carbide or Cr,
Al, Ni, Cu, W, Si, Ti, Sn, Fe, Zr
, Ta, Ce, and Zn. A method for producing an ultra-low core loss unidirectional silicon steel sheet, which comprises depositing a metal or metalloid element by evaporation and ionization, and ion-implanting a non-metallic element among the surface coating components onto the surface of the steel sheet. .