JPS6256202B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a (100) in-plane non-oriented silicon steel ribbon with extremely excellent magnetic properties, and in particular, the present invention relates to a method for manufacturing a (100) in-plane non-oriented silicon steel ribbon containing 2 to 8% Si, with the <100> axis of the crystal grains being parallel to the plate normal. The present invention relates to a method for manufacturing a (100) in-plane non-oriented silicon steel ribbon which has a highly oriented structure and has extremely excellent magnetic properties. Silicon steel sheets containing about 3% Si are widely used as iron core materials for electrical equipment. Such silicon steel sheets are usually finished by hot rolling and cold rolling, and grain-oriented silicon steel sheets, which have particularly excellent magnetization properties in one direction, usually in the rolling direction, require complicated annealing. Therefore, its manufacturing cost is much higher than that of other steel types. Recently, a technology has been disclosed in which molten steel is jetted from a circular or slit nozzle onto a rotating body such as a roller rotating at high speed and rapidly solidified to produce a ribbon, but Si2-8% is more suitable. When a ribbon containing 6 to 7% of
It is known that its manufacture is easy. Such silicon steel materials containing a large amount of Si are highly brittle, so those containing more than 5% Si cannot be made into thin strips using conventional rolling methods.
A silicon steel plate containing the above has never been produced industrially. By the way, the ribbon produced by the above-mentioned new method is highly strained in its original state, and its texture is not in a suitable state, so its magnetic properties are generally inferior to that of conventional silicon steel. is inferior.
Although annealing is performed to remove the strain, the magnetic properties are not improved much. The present invention provides a silicon steel quenched ribbon produced by injecting high Si-containing molten steel onto the moving cooling surface of a moving cooling body, rapidly cooling it, solidifying it, and then annealing it. The object of the present invention is to provide a method for eliminating and improving the drawbacks of poor performance, and this object can be achieved by the method described in the claims. Next, the present invention will be explained in detail. The present inventors have discovered that when a rapidly solidified silicon steel ribbon is annealed at high temperature in a vacuum within a certain degree of vacuum, the (100) planes are accumulated parallel to the ribbon surface, resulting in extremely good magnetic properties. The present invention was completed based on the new findings. Next, the present invention will be explained step by step. Silicon steel containing 2% or more of Si does not undergo r-transformation, so the crystal grains can be enlarged by annealing at high temperatures, and Si is one of the elements that increases electrical resistance the most when contained in Fe. Therefore,
Si is a preferable element for electrical steel sheets. Si is about
When contained in 6.5% Fe, magnetostriction almost disappears,
Therefore, it is known that the best characteristics can be expected because the iron loss is significantly reduced.
It is known that when the saturation magnetic flux density exceeds 1.8 T, the iron core becomes not only unsuitable for use in transformers, but also becomes extremely brittle, and magnetostriction increases, leading to an increase in iron loss. Furthermore, Mn is a useful element for improving magnetic properties and hot toughness, but if it is added in a large amount exceeding 0.1%, there is a strong possibility that the saturation magnetic flux density will deteriorate. Therefore, in the present invention, Si:2 to
8%, Mn: 0.1% or less. Furthermore, in the present invention, Al can be added in an amount of 0.1% or less in order to prevent the negative effects of O and N on magnetism and to further improve magnetic properties. The reason why the upper limit of Al content was regulated to 0.1% was because
This is because if it exceeds 0.1%, the saturation magnetic flux density will decrease. Note that the amount of additional avoidable impurities such as O, N, C, and P must be limited according to the intended grade. According to the present invention, when molten steel suitable for forming a ribbon having the above-mentioned composition is spouted from a container containing the molten steel onto the moving cooling surface of a moving cooling body through a suitably shaped nozzle attached to the container, the steel is rapidly cooled and solidified. Thin strips can be manufactured all at once. FIGS. 1 (1), (2), and (3) are perspective views of typical conventional apparatuses in which the movable cooling body is a single roll, twin rolls, or drum, respectively.
In the same figure, 1 is a molten steel container, 2 is a molten steel spouting nozzle attached to the container, 3 is a roll, and 4 is a drum. In (3), molten steel is ejected onto the inner peripheral cooling surface of the drum through a nozzle. Next, the present invention will be explained using experimental data. The present inventors prepared 1.0 mm thick
From a nozzle with a mm-wide rectangular slit
A thin ribbon with a thickness of 130 μm was obtained by ejecting it near the roll engagement part on the outer peripheral surface of twin rolls with a diameter of 500 mm rotating at 650 rpm. The average roughness Ra of the surface of this ribbon was approximately 1.5 μm, which was very smooth and had a silvery white metallic luster. After continuously ultrasonically cleaning this ribbon in ethyl alcohol, the temperature was raised from 800℃ to 1140℃ for 65 minutes, and vacuum annealing was performed at 1140℃ for 1 hour to expose the surface of the ribbon in vacuum. Annealing was performed at various degrees of vacuum. After this, a (200) X-ray pole figure of the ribbon was taken, and the average (200) X-ray intensity within a solid angle within a 10° inclination from the normal to the ribbon surface was investigated. The results are shown in FIG. The stronger the X-ray intensity, the more parallel the (100) plane becomes to the plate surface. In addition, when the (100) planes are aligned parallel to the plate surface, the <100> axis, which is the axis of easy magnetization, is aligned within the plate plane, and the magnetic properties when the ribbon is magnetized in the direction within the plate plane are good. become. In Figure 2, the degree of vacuum is 1×10 ^-2 ~5×
It can be seen that within the range of 10 ^-7 Torr and in the region where the annealing temperature is 1050°C or higher, a stable and highly integrated (100) in-plane non-directional structure can be obtained. In actual industrial production, vacuum annealing at a temperature higher than 1300°C is not only technically difficult but also increases production costs. That is, according to the present invention, if the degree of vacuum during vacuum annealing is lower than 1×10 ^-2 Torr, the magnetic properties will be poor, while if it is higher than 5×10 ^-7 Torr, the magnetic properties will not be particularly good. It is necessary to keep it within the range of ×10 ⁻² to 5×10 ⁻⁷ Torr, preferably within the range of 1×10 ⁻³ to 1×10 ⁻⁵ Torr. In addition, if the annealing temperature during vacuum annealing is lower than 1050℃, the magnetic properties will not improve, while if it is higher than 1300℃, the industrial cost will increase, so it is necessary to keep it within the range of 1050 to 1300℃. , more preferably within the range of 1150 to 1250°C. The magnetic properties in the longitudinal direction of the (100) in-plane non-oriented silicon steel ribbon manufactured by the present invention are W15/50 = 0.6 ~ when the X-ray intensity is about 5X.
0.9W/Kg, for something around 3X
W15/50=1.0 to 1.5 W/Kg, and it can be seen that these properties are comparable to those of grain-oriented silicon steel currently on the market. Current grain-oriented silicon steel sheets are manufactured through extremely complicated processes, resulting in high manufacturing costs, whereas the (100) in-plane non-oriented silicon steel ribbon according to the present invention can be manufactured through extremely simple processes. The cost is low, and therefore the method of the present invention is economically very advantageous. Next, the molten steel containing 3.5% Si, 0.03% Mn, and the remainder is essentially Fe, is passed through a multi-hole nozzle with 1.2mmφ holes lined up at 5.5mm intervals, each with a diameter of 45mm.
A thin strip with a thickness of 170 μm was created by ejecting it onto the outer tangent line of the biting part of two irregularly shaped twin rolls with a diameter of 500 mm. Among the ribbons thus created, ribbon A has a slight degree of oxidation on the surface and retains a considerable metallic luster;
Thin strip B, in which oxidation progresses at high temperatures and a thin layer of SiO ₂ is formed on the surface, is (a) immersed in a dilute sulfuric acid aqueous solution for 15 seconds, then washed and dried, and (b) a sodium silicate detergent. The surface of these thin strips was examined for five types: (c) electrolytically degreased, (d) ultrasonically cleaned with ether, alcohol, etc., and (v) no cleaning treatment at all. Vacuum annealing at approximately 10 ^-4 Torr was carried out using the heat pattern shown in FIG. 3 in the exposed state. Table 1 shows the X-ray intensities of these ribbons after vacuum annealing.

[Table] As is clear from the table, the temperature increase pattern is (a),
The ones in (b) and (c) have a strong (100) in-plane non-directional structure, while the ones in (d) and (e) have a (100) in-plane cubic structure. Organizational development is inhibited. In addition, if the surface of the ribbon is cleaned by pickling (a) or cleaning (b) to expose the metal surface before annealing, a good (100) in-plane non-directional structure can be obtained. I understand. In other words, it has been found that if a ribbon with exposed metal surfaces is subjected to high temperature annealing in an appropriate degree of vacuum at a high heating rate, a good structure can be obtained and a product with excellent magnetic properties can be obtained. Such a phenomenon is generally 3
It is thought that this occurs due to secondary recrystallization, and the surface energy of the (100) plane is the lowest within a certain vacuum degree and temperature region, and therefore, the surface energy of the (100) plane is the lowest. It is assumed that only the crystal grains on the exposed surfaces grow. In steel, the growth of grains, that is, the movement of grain boundaries, is approximately 10
For crystal grains larger than μm, this becomes noticeable at temperatures above 800°C.
According to the experimental examples of the present invention, tertiary recrystallization occurs at temperatures above 1050°C, and when the annealing time from 800°C to 1050°C is long, normal grain growth occurs during this time, and grains with various orientations are randomly formed. Since it has grown to
Even if it is kept at a high temperature of 1050℃ or higher, it will no longer (100)
It becomes difficult for only grains with faces to grow.
As can be seen from Figure 3, if the average heating rate from 800℃ to 1050℃ is less than 100℃/hr, a good (100) plane structure cannot be obtained. In order to obtain the structure, the temperature was raised at an average rate of 100° C./hr or more in the temperature range of at least 800 to 1050° C. during annealing. Further, in the present invention, the ribbon after being rapidly solidified may be rolled prior to the above-mentioned cleaning and annealing treatment. Particularly when it is necessary to strictly control the plate thickness to a predetermined value, it is preferable to carry out such rolling. Furthermore, since magnetic properties can be improved by smoothing the surface properties, it is advantageous to smooth the surface of the ribbon by rolling. Such a rapidly solidified ribbon has fine crystal grains and is also thin to begin with, so even if it is made of Si,
Even high-silicon steel containing about 8% of silicon can sufficiently withstand rolling. Next, the present invention will be explained with reference to examples. Example 1 Si2.1%, Mn0.08%, C0.006%, O0.003%,
A 180 μm thick ribbon was produced using a single roll method from molten steel containing 0.005% N and the remainder substantially Fe. After rolling this ribbon to a thickness of 100 μm, it was electrolytically degreased, then annealed by increasing the temperature from 800°C to 1200°C at a rate of 500°C/hr, and then annealing at 1200°C for 8 minutes in a vacuum chamber. was applied. The average (200) X-ray intensity and iron loss within 10° of the product were as shown in Table 2 below, depending on the degree of vacuum.

[Table] Example 2 Molten steel containing 7.6% Si, 0.08% Mn, and 0.05% Al, with the remainder essentially Fe, was processed to a thickness of 80 μm using a twin roll method.
A thick thin strip was created. 8% of this thin strip at 75℃
The oxide layer was removed by immersion in an aqueous H ₂ SO ₄ solution for 10 seconds, and after ultrasonic cleaning, vacuum annealing was performed for various times. Vacuum degree is 5×10 ^-3 to 8×10 ^-4 Torr
The temperature was 1180°C. 800℃ to 1050
The temperature was raised to ℃ in about 20 minutes (heating rate: about 750℃/hr). The results are shown in Table 3 below.

[Table] The ribbon obtained by the present invention can be subjected to a coating treatment for insulation, if necessary, and used as an iron core material for electrical equipment.

[Brief explanation of the drawing]

Figure 1 (1), (2), and (3) are perspective illustrations of typical ribbon manufacturing equipment that uses single rolls, twin rolls, and drums, respectively, and Figure 2 shows the degree of vacuum (Torr) and annealing. A diagram showing the influence of the relationship with temperature °C on the average X-ray intensity within 10° from the surface normal. Figure 3 is a diagram showing various heat patterns during vacuum annealing in the research of the present invention. be.

Claims (1)

[Claims] 1. Molten steel containing 2.0 to 8.0% Si, 0.1% or less Mn, and the remainder being substantially Fe is spouted from a nozzle onto the moving cooling surface of a moving body moving at high speed. , in a method for producing silicon steel ribbon in which the ribbon is continuously formed by rapid cooling and solidification, and then annealed, the ribbon after rapid solidification is pickled and then annealed.
At least one surface cleaning treatment selected from cleaning, electrolytic degreasing, and ultrasonic cleaning is performed, and then annealing is performed from at least 800°C to 1050°C at an average heating rate of 100°C/hr or more. The temperature is increased, and then at least one side of this ribbon is heated at 1×10 ^-2 to
A method for manufacturing a non-oriented silicon steel ribbon with excellent magnetic properties, which comprises annealing the ribbon while exposing it in a vacuum of 5×10 ^-7 Torr for 3 minutes or more. 2. Molten steel containing 2.0 to 8.0% Si, 0.1% or less Mn, and the remainder being essentially Fe is jetted from a nozzle onto the moving cooling surface of a moving object that moves at high speed, and is rapidly cooled and solidified. In the manufacturing method of silicon steel ribbon that is continuously formed into a ribbon and then annealed, the ribbon is rapidly solidified and rolled prior to annealing, followed by pickling, cleaning, electrolytic degreasing, and ultrasonic cleaning. At least one surface cleaning treatment selected from the above is applied, and then annealing is performed at least 100°C from 800°C to 1050°C.
Raise the temperature at an average heating rate of ℃/hr or more, and continue to 1050℃.
Magnetic properties characterized by annealing within a temperature range of ~1300°C while exposing at least one side of the ribbon in a vacuum of 1 × 10 ^-2 to 5 × 10 ^-7 Torr for 3 minutes or more. An excellent method for producing non-oriented silicon steel ribbon. 3. Molten steel containing 2.0 to 8.0% Si, 0.1% or less Mn, and 0.1% or less Al, with the remainder being substantially Fe, is spouted from a nozzle onto the moving cooling surface of a moving body that moves at high speed. , in a method for producing silicon steel ribbon in which the ribbon is continuously formed by rapid cooling and solidification, and then annealed, the ribbon after rapid solidification is pickled and then annealed.
At least one surface cleaning treatment selected from cleaning, electrolytic degreasing, and ultrasonic cleaning is performed, and then annealing is performed from at least 800°C to 1050°C at an average heating rate of 100°C/hr or more. The temperature is increased, and then at least one side of this ribbon is heated at 1×10 ^-2 to
A method for manufacturing a non-oriented silicon steel ribbon with excellent magnetic properties, which comprises annealing the ribbon while exposing it in a vacuum of 5×10 ^-7 Torr for 3 minutes or more. 4. Spraying molten steel containing 2.0 to 8.0% Si, 0.1% Mn, and 0.1% or less Al, with the remainder essentially having a composition of Fe from a nozzle onto the moving cooling surface of a moving body moving at high speed, In the manufacturing method of silicon steel ribbon, which involves rapid cooling and solidification to continuously form a ribbon and then annealing, the ribbon after rapid solidification is rolled prior to annealing, and then pickled, cleaned, and electrolyzed. At least one surface cleaning treatment selected from degreasing and ultrasonic cleaning is performed, and then annealing is performed at least 100°C from 800°C to 1050°C.
Raise the temperature at an average heating rate of ℃/hr or more, and continue to 1050℃.
Magnetic properties characterized by annealing within a temperature range of ~1300°C while exposing at least one side of the ribbon in a vacuum of 1 × 10 ^-2 to 5 × 10 ^-7 Torr for 3 minutes or more. An excellent method for producing non-oriented silicon steel ribbon.