JP2001303137A - Method for producing grain oriented silicon steel excellent in coil shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing grain oriented silicon steel by which the generation of buckling, crushing, telescoping, adverse, or the like, is prevented without exerting an influence on its magnetic properties, in its turn, crop loss is reduced, and the yield can be improved. SOLUTION: As main agent of a separation agent for annealing to be applied, the one in which, as powder characteristics before slurrying, the angle of repose is 0.61 rad (35 deg.) to 1.17 rad (67 deg.), bulk height is 0.0027 m3/kg (2.7 ml/g) to 0.00733/kg (7.3 ml/g) and the tapping coefficient is 0.47 to 0.68 and, after slurrying, the ratio of the grains with a grain size of >=40 μm is <=5 mass % is used. The coiling tension of a coil after the application of the separation agent for annealing is controlled to 49 MPa (5 kgf/mm2) to 147 MPa (15 kgf/mm2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing oriented silicon steel used for iron cores of transformers and other electric equipment and the like. An object of the present invention is to propose a method for preventing a decrease in yield due to crushing, buckling, or the like.

[0002]

2. Description of the Related Art To produce oriented silicon steel, a steel slab is subjected to cold rolling after hot rolling, then to decarburizing annealing, and then to final finishing annealing for secondary recrystallization. It is common. Secondary recrystallization occurs during the final finish annealing, and coarse crystal grains having a uniform axis of easy magnetization in the rolling direction are generated, thereby obtaining a steel sheet having excellent magnetic properties. Since the final finish annealing is performed at a high temperature and for a long time in a state where the steel sheet is wound in a coil shape, an annealing separating agent is applied to the steel sheet surface prior to the final finish annealing for the purpose of preventing seizure of the steel sheet. .

[0003] The step of applying such an annealing separating agent is usually carried out.
The annealing separator is suspended in water and stirred to form a slurry. The slurry is applied to the surface of a steel sheet by a roll coater or the like, dried in a drying furnace, and then wound around a coil. At this time, the coil may buckle due to slippage of the annealing separating agent, or a bamboo shoot-like winding deviation called a telescope may occur in the coil. After winding, finish annealing is performed for a long time at high temperature while maintaining the coil shape.The annealing separator sinters during this finishing annealing, and the annealing separator reacts with the oxide film on the steel sheet surface. Since the volume of the annealing separating agent is reduced by forming the coating film, the winding tension of the coil is reduced and the coil may be crushed. These buckles,
When the telescope or the crush occurs, the crop loss increases, and the product yield is greatly reduced. Therefore, various measures have been taken to solve these problems.

For example, Japanese Patent Application Laid-Open No. 55-1107 discloses a method of preventing ear elongation and buckling by changing the amount of annealed separating agent applied.
No. 21, JP-A-50-89719 and JP-A-63-8467
No. 0 proposes a technique for changing the coating amount in the coil plate width direction. Regarding the method of changing the coil winding tension, Japanese Patent Publication No. 3-33766 and Japanese Patent Application Laid-Open No. 63-140035 propose a technique of changing the tension value in the coil longitudinal direction. Further, Japanese Patent Application Laid-Open No. 11-246913 proposes a method of controlling the winding tension and the applied amount of an annealing separating agent to specific values in an inner winding portion, a middle winding portion, and an outer winding portion, respectively. However, in the above-described method of changing the coating amount, a problem that a telescope is easily generated and magnetic deterioration occurs in a portion where the coating amount is small occurs. In addition, the method of changing the winding tension induces the slip of the annealing separator at a place where the winding tension is low, and the coil may buckle. Furthermore, if the tension of the inner winding part is set too high, it is called buckling,
There was a problem that several turns of the inner winding were bent in a direction opposite to the circumference. From these points, there is a limit to improvement by a method that only adjusts the application amount and the winding tension,
The above problems were not fully resolved.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and prevents the occurrence of buckling, crushing, telescope or buckling without adversely affecting magnetic properties. Accordingly, it is an object of the present invention to propose a method for producing a directional silicon steel capable of improving crop yield by reducing crop loss.

[0006]

According to the present invention, Si: 1.5 to
After heating a directional silicon steel material containing 7.0 mass%, it is hot-rolled, cold-rolled once or multiple times including intermediate annealing, and finished to the final sheet thickness, and then subjected to primary recrystallization annealing. And then applying an annealing separator slurried with water,
In a method for producing a grain-oriented silicon steel comprising a series of steps of drying and then performing a final finish annealing, the base material of the annealing separator to be applied has a repose angle of 0.
61rad (35 °) or more and 1.17rad (67 °) or less
0.0027m ³ / kg (2.7ml / g) or more, 0.0073m ³ / kg (7.3ml / g) or less, tapping coefficient 0.47 or more and 0.68 or less. Using a certain material, the winding tension of the coil after applying the annealing separating agent was 49 MPa
(5 kgf / mm ² ) or more and 147 MPa (15 kgf / mm ² ) or less, which is a method for producing a directional silicon steel excellent in coil shape. In the present invention, the main component of the annealing separator has a linear shrinkage of 23% or less from room temperature to 1473K,
Fits more advantageously.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted various studies to find conditions for eliminating troubles such as crushing of a coil. As a result, the physical properties of the base material of the annealing separator and the winding tension of the coil are optimized. As a result, they newly discovered that the frequency of occurrence of these troubles was almost 0%. The following describes the experiment that led to this finding.

C: 0.04 to 0.05 mass% (hereinafter simply referred to as “%”)
Indicated by ), Si: 3.3 to 3.4%, Al: 0.021 to 0.027
%, N: 0.007 to 0.009%, Mn: 0.06 to 0.075%, Se:
0.018-0.020%, Sb: 0.02-0.03% and Cu: 0.08-0.1
After heating a silicon steel slab consisting essentially of Fe for 18000s at 1623K, hot-rolling it to a thickness of 2.2mm, then performing hot-rolled annealing at 1173K for 60s Then, it was cold-rolled by a tandem rolling mill at 393 K to a thickness of 0.23 mm to finish to a final thickness. After decarburizing annealing, N in Table 1
o. 1,5,6,7,9 Various kinds of magnesia with powder properties of 5% titania added to magnesia
m ² , hydration temperature 293K, hydration time 24000s, hydrated and applied,
Let dry.

[0009]

[Table 1]

In Table 1, the bulk was measured by the method of JIS-K5101. The angle of repose measured the angle formed between the horizontal surface and the deposited powder when the powder was deposited on the horizontal surface in the same manner. The linear shrinkage rate is 980MPa (100kgf / mm ² )
Then, the temperature was raised at a rate of 0.0083K / s (30 ° C / h) in an N ₂ atmosphere, and after reaching 1473K, the furnace was cooled, and the rate of size change before and after this heat treatment was determined. Things.

[0011] The tapping coefficient is defined here as JIS.
Using a container as defined in -K5101 method to measure the bulkiness (to this value as V _0), the diameter is fitted to the frame of the same size, the powder is deposited, drop height 0.018m Tapping 100 times, then removing the frame, scraping the powder off the outer edge of the container, and re-measuring the bulk (measured as Vf) from the initial bulk divided by the initial bulk height (V ₀ −Vf)
/ V ₀ .

Further, the content of the powder having a particle size of 40 μm is determined as follows: 0.02 kg of the powder is once put in water, stirred and slurried, and then put into a sieve having an opening of 40 μm, and the tap water is used. The slurry was passed while washing the sieve, the sieve was dried, and the mass ratio of the unsieved residue was measured.

After applying and drying the annealing separating agent, the film was wound on a tension reel at a winding tension of 39.2 MPa (4 kgf / mm ² ) and 78.4 MPa (8 kgf / mm ² ). Next, final finishing annealing was performed on the coil. Table 2 shows the results of visually observing the defective shape of the coil after the tension reel was pulled out and after the final finish annealing. In this table, the shape defects after annealing were counted as those occurring after annealing for those that became more severe as compared with the shape defects before annealing.

[0014]

[Table 2]

As is clear from Table 2, powder No. 9
78.4MPa (8kgf / mm ^Two)
The occurrence rate of coil shape defects is 0% for all items.
Was. On the other hand, No. 1 with low angle of repose and low bulk
No.3, coil shape defects before final annealing frequently occurred
Was. On the other hand, for No. 6 with a high tapping coefficient,
Ear extension, buckling, buckling, etc. occurred after dulling. Ma
Even when powder No. 9 is used, the winding tension is low.
Under conditions, severe collapse, telescope, ear buckling, etc.
I was born.

Although the cause of obtaining such a result is not always clear, the present inventors consider as follows. The most common method for improving the shape defect of the coil during the finish annealing is to adjust the winding tension. Here, if the winding tension is too weak, the steel plate slips, so that the telescope is likely to occur.On the other hand, if the winding tension is too strong, the ear elongation tends to occur, and the tension increases the pressure in the inner circumferential direction of the coil. Buckling and buckling and crushing are likely to occur. Therefore, if the winding tension is reduced to some extent and the friction coefficient of the annealing separator is increased to suppress slippage, the coil shape is considered to be improved. In order to increase the coefficient of friction of the annealing separator, it is sufficient to increase the adhesive force between the powders. For this reason, it is important to increase the angle of repose and the height of the powder which is the main component of the annealing separator. However, even if only the adhesion between the powders is increased, if the fluidity is high, the particles are rearranged due to vibration when the coil is taken out of the reel or transported after being wound on the coil. Work to reduce surface pressure
At the time of handling after finish annealing, it also slips and causes a defective coil shape. Therefore, in order to sufficiently achieve the intended purpose, it is important to adjust the winding tension, improve the adhesive force of the powder, and lower the fluidity of the powder. Therefore, in the present invention, the tapping coefficient is optimized. That is, lowering the tapping coefficient to a level within the range of the present invention while increasing the angle of repose and the height of the repose corresponds to making the flow between particles less likely to occur while maintaining the adhesive force between the powders. . Furthermore, even if the adhesive strength between the powders is high, the presence of coarse powder acts to lower the coefficient of friction between the steel sheets, so that it is necessary to lower the coarse component. By satisfying all of these properties, slipping when applying an annealing separating agent with high adhesive strength and winding it around a coil is reduced, making it difficult for telescopes to occur, and particles with low fluidity It is considered that the rearrangement of the alloy hardly occurs, the loosening after the finish annealing is reduced, and the buckling and buckling after the annealing are reduced.

[0017] During the final annealing, the annealing separating agent may be sintered or consumed by the reaction of forming a film, and may loosen even though the above properties are satisfied. Therefore, it is desirable to reduce the linear shrinkage of the annealing separator in order to obtain the desired effect of the present invention.

Next, the present invention will be described in more detail.
The silicon-containing steel that is the material of the present invention is not particularly limited as long as it is a material for oriented silicon steel, and the typical component composition range is as follows. First, C is used in cases where decarburizing annealing is not performed by reducing the amount of C during the tapping stage, while a certain amount of C is secured to improve the structure during rolling, and the amount of C is reduced by subsequent decarburizing annealing. May be lowered.
In the former case, it should be 0.01% or less to avoid the adverse effect of C,
In the latter, the preferred range of the tissue improvement is 0.01% or more and 0.10% or less. Next, Si is 1.5 to 7%. Less than 1.5%,
Above 7%, the effect of reducing iron loss is reduced.

In addition to C and Si, an inhibitor component is added. AlN, MnS, MnSe and the like are well known as inhibitors, and any of these may be used, or two or more of these may be used in combination. When MnS and / or MnSe is used as the inhibitor, Mn: 0.03 to
0.5% and the total amount of S and Se: 0.01 to 0.03%. AlN
When used as an inhibitor, Al: 0.005 to 0.04%,
N: 30 to 120 ppm. In any case, when the amount is lower than these ranges, the effect as an inhibitor does not work, and when the amount is higher, the secondary recrystallization becomes unstable.

In addition to these main inhibitors,
B, Cu, Sn, Cr, Sb, Ge, M as auxiliary inhibitors
One or more of o, Te, Bi, P, V and the like can be used. The concentration effective for the function as an inhibitor is 0.01% or more and 0.2% or more in the total amount of the auxiliary inhibitor.
It is as follows. Each of these inhibitors can be used alone or in combination.

After these materials are hot-rolled by a known method, they are cold-rolled once or a plurality of times with intermediate annealing to obtain a final thickness. Further, if necessary, the hot rolled sheet can be annealed before cold rolling. After cold rolling, primary recrystallization annealing is performed, and a final finish annealing is performed after applying an annealing separating agent.

The method of improving the coil shape proposed in the present invention has a point in the process from the application of the annealing separator to the final finish annealing, and the improvement is added to this point to prevent the coil shape from deteriorating. .

First, as the annealing separator, the repose angle of the main component, that is, the powder constituting 40% or more of the entire annealing separator is 0.61 rad (35 °) to 1.17 rad (67 °), and the bulk height is 0.0027. m ³ / kg (2.7ml / g) or more 0.0073m ³ / kg (7.3ml / g)
Hereinafter, the tapping coefficient is set to 0.47 or more and 0.68 or less, the particle size of 40 μm or more after slurrying is set to 5% or less by mass ratio, and the winding tension of the coil after applying the annealing separating agent is 49 MPa (5 kg).
f / mm ² ) or more and 147 MPa (15 kgf / mm ² ) or less. If the angle of repose is too low, the adhesive force between the powders becomes weak, and a shape defect such as a telescope tends to occur. Conversely, if it is too high, the filling property will decrease, buckling after finish annealing will easily occur, and a bridge will be formed during handling such as pouring powder into the hopper or cutting out from the hopper. This causes problems such as clogging of powder and slowing of replacement of water with air when slurrying, and adhesion of powder to walls. Therefore, in the present invention, the angle of repose is set to 0.61 rad (35
°) or more and 1.17rad (67 °) or less. Similarly, if the bulk height is too low, the adhesion between the powders will be low, and if the bulk height is too high, problems such as bridge formation and wall adhesion will occur. On the other hand, if the bulk height is too high, the filling property of the particles becomes low, and the shape of the coil after finish annealing tends to be poor. Therefore, in the present invention, the bulk height is 0.0027 m ³ / kg (2.7 ml / g)
Not less than 0.0073m ³ / kg (7.3ml / g). If the tapping coefficient is too high, the fluidity of the powder is strong, and the powder is rearranged during handling. The powder loses its strength and it is easy for the powder to come off the steel plate. Therefore, in the present invention, the tapping coefficient is set to 0.47 or more and 0.68 or less. The content of powder having a particle size of 40 μm or more is set to 5% by mass or less. When the proportion of particles having a particle size of 40 μm or more is more than 5% by mass of the entire base material of the annealing separator, such coarse particles have a function of lowering the friction coefficient between steel sheets.

Methods for obtaining an annealing separator having such characteristics include, for example, optimizing the particle size distribution of the powders to adjust the van der Waals force acting on the powders, and reducing the pulverization time of magnesia. For example, there is a method of adjusting the amount of charge of the powder by optimizing the amount, and a method of adjusting the moisture adsorption layer on the back surface by optimizing the exposure time of the powder in a slight moisture atmosphere.

The winding tension when winding the coil after applying the annealing separating agent is 49 MPa (5 kgf / mm ² ) or more and 147 MPa (15 kgf / mm ² ).
mm ² ) or less. If the pressure is lower than 49 MPa, telescope and crushing tend to occur. On the other hand, if the pressure is higher than 147 MPa, crushing tends to occur. In addition, winding tension
The taper may be provided along the longitudinal direction of the plate as in JP-A-110721 and JP-A-50-89719. At this time, the average tension is adjusted to 5 to 15 kgf / mm ² .

The linear shrinkage ratio is desirably 23% or less. If it exceeds 23%, the annealing separator may be sintered or consumed by the reaction of the coating during the finish annealing, and may loosen while satisfying the above properties.

In addition, optimizing the coating amount is also well known for suppressing the coil shape defect. In the present invention, as in the conventional case, a good result is obtained at 5 to 20 g / m ² per both sides of the steel sheet. can get.

After the application of the annealing separating agent, final finish annealing is performed. The final finish annealing may be performed by a known method. After these series of treatments, a tension film coat is applied, and flattening annealing is performed to finish the product. By such a processing step, oriented silicon steel can be obtained at a high yield without a coil shape defect.

[0029]

EXAMPLES (Example 1) C: 0.05 to 0.07%, Si: 3.2 to 3.
5%, Mn: 0.06-0.075%, Se: 0.018-0.021%, S
b: A silicon steel slab containing 0.02 to 0.03%, with the balance being substantially Fe, heated at 1623K for 1800s and then hot-rolled.
After 2mm thickness, hot rolled sheet annealing at 1173K, 60s, then intermediate annealing at 1273K, 60s, cold rolling to 0.23mm thickness at 393K by tandem rolling mill, and final thickness Finished. After decarburizing annealing, this is shown in Table 1, 2, 4, 6, 10, 1
Hydrate at an application rate of 13 g / m ² , hydration temperature of 293 K, hydration time of 2400 sec, and apply to various magnesia with powder retention of 1-17 with strontium sulfate 1.5% applied, and dry. I let it. This was wound up on a tension reel with a winding tension of 147 MPa.

Thereafter, final finishing annealing was performed on the coil. Table 3 shows the results of visually determining the defective shape of the coil at this time. N that satisfies the requirements of this invention
When magnesia of o.10, 11-17 is used, the defective shape of the coil is small.

[0031]

[Table 3]

(Example 2) C: 0.05-0.07%, Si: 3.2-
3.5%, Mn: 0.06-0.075%, Se: 0.018-0.021%,
Sb: 0.02 to 0.03%, the remainder being substantially Fe-silicon steel heated at 1623K for 1800s, hot-rolled to 2.2mm thickness, and then hot-rolled at 1173K for 60s After the intermediate annealing at 1273K for 60s, the sheet was cold-rolled to a final thickness of 0.23mm at 393K using a tandem rolling mill. This was decarburized and annealed, and then applied to magnesia having the powder properties of Nos. 8 and 9 in Table 1 with an annealing separator containing 1.5% of strontium sulfate added at 13 g / m ² , hydration temperature of 293 K and hydration time of 2400
Hydrated in sec, applied and dried. This was wound up on a tension reel with a winding tension of 147 MPa.

Thereafter, final finishing annealing was performed on the coil. Table 4 shows the results of visually determining the defective shape of the coil at this time. Almost good results were obtained using either powder, but by setting the linear shrinkage ratio to an appropriate value, all coil shape defects did not occur.

[0034]

[Table 4]

[0035]

According to the present invention, a steel material containing 1.5 to 7.0% of Si is heated, then hot-rolled, and cold-rolled once or a plurality of times including intermediate annealing to obtain a final sheet thickness. After finishing, subjected to primary recrystallization annealing, then apply an annealing separating agent slurried with water, dried and then subjected to a final finish annealing in a method of manufacturing a grain oriented silicon steel sheet comprising a series of steps of performing Angle of repose of the main agent of the annealing separator
d (35 °) or more and 1.17rad (67 °) or less, bulk height 0.0027m
³ / kg (2.7 ml / g) or more and 0.0073 m ³ / kg (7.3 ml / g) or less, the tapping coefficient is 0.47 or more and 0.68 or less, and the winding tension of the coil after application of the annealing separator is 49 MPa (5 kgf / mm ² ) Over 14
The content of powder having a particle size of 7 MPa (15 kgf / mm ² ) or less and a particle size of 40 μm or more should be 5 mass% or less, and the linear shrinkage ratio of the annealing separator main agent from room temperature to 1473 K should be 23% or less. By doing so, the occurrence of defective shape of the coil is suppressed, and directional silicon steel can be manufactured with a high yield.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) // C21D 1/70 C21D 1/70 B (72) Inventor Hiroro Toda 1-chome, Mizushima Kawasaki-dori, Kurashiki City, Okayama Prefecture (No address) Inside Mizushima Works, Kawasaki Steel Corporation (72) Inventor Honda, Atsuto 1-chome, Mizushima Kawasaki-dori, Kurashiki-shi, Okayama Prefecture (No address) Inside Mizushima Works, Kawasaki Steel Corporation F-term (reference) BA12 BB05 BB10 CA16 CA18 CA33 DA02 DA11 EA17 EB02 EB11 4K033 RA04 TA02 5E041 AA02 BC01 CA02 HB05 HB07 HB11 HB14 NN05 NN17

Claims (2)

[Claims] A directional silicon steel material containing Si: 1.5 to 7.0 mass% is heated, hot-rolled, and cold-rolled once or a plurality of times including intermediate annealing to obtain a final sheet thickness. After finishing, a primary recrystallization annealing is performed, and thereafter, an annealing separating agent slurried with water is applied, dried, and then subjected to a final finish annealing. The angle of repose is 0.61 rad (35 °) or more and 1.17 rad (67 °)
Below, bulk height is 0.0027m ³ / kg (2.7ml / g) or more, 0.0073m ³
/ kg (7.3ml / g) or less, the tapping coefficient is 0.47 or more and 0.68 or less, and the particle size of 40μm or more after slurrying is 5% by mass ratio.
% Or less, and the coil tension after application of the annealing separator is 49 MPa (5 kgf / mm ² ) or more and 147 MPa (15 kgf / mm ² ) or less. Steel production method. 2. The method for producing grain-oriented silicon steel according to claim 1, wherein the main component of the annealing separator has a linear shrinkage of 23% or less from room temperature to 1473K.