JPH059704A - Production of high-silicon steel strip by continuous line - Google Patents

Abstract

PURPOSE:To provide the process for production of the high-silicon steel strip which can continuously produce the high-silicon steel strip having a uniform Si quantity without having shape defects by a continuous diffusion penetration treatment of Si. CONSTITUTION:Plural slit nozzles 1 are disposed to face the front and rear surfaces of a steel strip apart spaced intervals in the longitudinal direction of a reaction furnace. Reactive gases are supplied to the individual slit nozzles 1 from the ends on one side thereof. The above-mentioned reactive gases are supplied from the alternately varying end sides of the plural slit nozzles 1 disposed apart the spaced intervals in the longitudinal direction of the furnace. The reactive gases are blown to the front and rear surfaces of the steel strip from these slit nozzles 1. More preferably, [the length 2 of the slit nozzles]/[the width of the steel strip] is regulated to a specific range and the steel strip is so passed that the one edge of the steel strip passes the position near the slit end on the gas supply side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously producing high silicon steel strip by a diffusion infiltration method.

[0002]

2. Description of the Related Art Silicon steel sheets are widely used as core materials for transformers and motors because they have excellent soft magnetic properties. It is known that this type of steel sheet exhibits excellent magnetic properties such that the iron loss is reduced as the Si content increases, and the magnetostriction becomes 0 and the maximum magnetic permeability peaks when Si content is 6.5 wt%.

Conventionally, there are a rolling method, a direct casting method and a diffusion infiltration method as a method for producing a silicon steel sheet. Among them, the rolling method can produce Si contents up to about 4 wt%, but more Si is required. If the content is too low, the workability is remarkably deteriorated, which makes cold rolling difficult. Further, the direct casting method does not cause the problem of workability unlike the rolling method, but has many problems such as easily causing a defective shape and being unable to manufacture a thick material or a wide material.

On the other hand, in the diffusion infiltration method, low silicon steel is melted in advance and thinned by rolling, and then Si is applied from the surface.
To produce high silicon steel strip by infiltrating
According to this method, a high silicon steel strip can be obtained without causing workability problems. Production of a high silicon steel sheet by this diffusion infiltration method is generally carried out by adding S such as SiCl ₄ to an ordinary steel sheet or a low silicon steel sheet (usually Si: 4 wt% or less).
Si is permeated from the surface of the steel sheet by performing Si infiltration treatment (siliconization treatment) in an atmosphere of non-oxidizing gas containing i compound,
Then, the steel sheet is subjected to a diffusion heat treatment in a non-oxidizing gas atmosphere containing no Si compound to diffuse the infiltrated silicon into the steel sheet to obtain a high-silicon steel sheet containing Si uniformly. .

Conventionally, with respect to this type of manufacturing method, various conditions for continuously processing a steel strip have not been sufficiently examined, and the processing time is as long as 30 minutes or more and the processing temperature is 1
There was a problem that the processing conditions could not be applied to a continuous line practically such that the edge portion was melted at an extremely high temperature of 230 ° C. and stable production in a continuous line of steel strip could not be expected.

To address such a problem, the present applicant has previously
A method for producing a silicon steel strip in which the diffusion and infiltration method is applied to a continuous line is disclosed in JP-A-62-227078 and JP-A-62-2.
Proposed as No. 27091. These methods, heating the steel strip, after continuously siliconizing treatment by chemical vapor deposition in a non-oxidizing gas atmosphere containing SiCl _4, SiCl ₄
Si is subjected to diffusion soaking in a non-oxidizing gas atmosphere that does not contain
The present invention relates to a method for efficiently producing a silicon steel strip by serializing a series of processes for homogenizing and cooling and coiling it into a coil. The thermal diffusion treatment time and the treatment temperature are studied and specified in detail, and it is possible to manufacture a high silicon steel strip by diffusion permeation treatment in a continuous line.

[0007]

However, according to the subsequent studies by the present inventors, the manufacturing method in which the processing conditions are specified as described above solves the problem which has hitherto been an obstacle to continuous line formation, Although it is possible in principle to efficiently manufacture high-silicon steel strips, the Si concentration in each part of the steel strip when the steel strip is processed,
In particular, it has been found that there is a problem that the Si concentration distribution in the plate width direction becomes non-uniform. Such non-uniformity of the Si amount causes a shape defect due to the difference in lattice constant due to the difference in the Si amount, and causes unevenness in magnetic characteristics due to the difference in the Si amount.

According to the present invention, in such a method for producing a high silicon steel strip by the continuous diffusion and permeation treatment of Si, a high quality high silicon steel strip having a uniform Si content and no shape defect is continuously and stably provided. It is intended to provide a method for manufacturing.

[0009]

Therefore, the present invention has the following constitution. (1) In a method for producing a high-silicon steel strip by subjecting a steel strip to a siliconizing treatment in which a Si penetrates from its surface in a reaction furnace and diffusing this Si in the plate thickness direction, A plurality of slit nozzles facing each other are arranged at intervals in the longitudinal direction of the furnace, and the reaction gas is supplied to each slit nozzle from one end thereof, and a plurality of slits are arranged at intervals in the longitudinal direction of the furnace. A method for producing a high silicon steel strip in a continuous line, characterized in that the reaction gas is supplied alternately from different end sides of nozzles, and the reaction gas is sprayed from the slit nozzles to the front and back surfaces of the steel strip.

(2) In the method of (1) above, a slit nozzle of [nozzle slit length] / [steel strip width]: 1.05 to 1.4 is used, and one of the steel strips is provided for each slit nozzle. The steel strip is passed through such that the edge portion of the steel strip passes between the slit end on the gas supply side and a position at a distance corresponding to 5% of the width of the steel strip from the slit end toward the other end of the slit. A method for producing a high silicon steel strip in a continuous line, characterized in that a gas is sprayed onto the steel strip by a slit nozzle.

[0011]

In the present invention, the steel strip is applied to the steel strip from the surface thereof in the reactor.
When performing the siliconizing treatment for infiltrating i, a plurality of slit nozzles are arranged above and below the steel strip passage line in the reactor at intervals in the furnace longitudinal direction. 1 and 2 show the configuration of this slit nozzle. The slit nozzle 1 is formed by forming a slit 2 on a nozzle body having a rectangular tube shape or a cylindrical shape, and supplying a reaction gas from one end portion of the nozzle body,
The other end is closed.

Since this type of nozzle cannot have a high head pressure, the flow velocity per nozzle has a distribution as shown in FIG. 3, and therefore the distribution of the amount of siliconized steel strip immediately below the nozzle forms a large distribution. It will be. The inventors of the present invention sprayed a mixed gas (reaction gas) of silicon tetrachloride and nitrogen onto the surface of the steel strip from one slit nozzle, and investigated the distribution of the amount of Si actually formed in the width direction of the steel strip. FIG. 4 shows the slit positions of the nozzles in the plate width direction and the corresponding Si amount distribution in the plate width direction.
As can be seen from the figure, the amount of siliconization in the width direction of the steel strip forms an extremely large distribution having a large peak on the terminal end side (closed end side) of the nozzle.

Therefore, in the present invention, as shown in FIGS. 5 and 6, for a plurality of nozzles arranged in the longitudinal direction of the furnace, the reaction gas is alternately supplied from different end sides so that the nozzles shown in FIG. By canceling out the Si amount distributions as shown in (3), a uniform siliconizing amount is obtained in the plate width direction.

Further, according to the Si amount distribution shown in FIG. 4, it is found that there is a straight line portion (illustrated) in the Si amount distribution in the width direction of the steel strip. Therefore, if the steel strip can be subjected to the siliconizing treatment only within the range of the straight line portion of the nozzles, by using a plurality of nozzles and alternately supplying the reaction gas from different end sides, it is possible to reduce the gap between the adjacent nozzles. It is possible to cancel the Si amount distribution more accurately. That is, by passing the steel strip through such a plurality of nozzles, it is possible to finally produce a high silicon steel strip having a uniform Si amount distribution in the plate width direction.

The inventors of the present invention used two sets of upper and lower adjacent slit nozzles to which the reaction gas is supplied from the nozzle end portions in the directions opposite to each other. A treatment test was performed to examine the relationship between the ratio of the nozzle slit length and the steel strip width and the fluctuation width of the Si amount in the steel strip width direction.

FIG. 7 shows this result. In order to suppress the fluctuation of the Si amount in the width direction of the steel strip, it is necessary to set the ratio of [nozzle slit length] / [steel strip width] within a predetermined range. I know that there is. Specifically, the fluctuation range of the Si amount is set to 0.25
In order to suppress it to more than wt%, [nozzle slit length] /
[Steel band width] is 1.05 to 1.4, and in order to suppress the fluctuation range of the Si amount to 0.15% or less, the ratio is 1.1 to
It turns out that it is necessary to set it to 1.25. In this way, there is an appropriate range for [nozzle slit length] / [steel strip width] when the ratio is too small, the amount of gas hitting the steel strip edge is insufficient, and the amount of siliconization at the edge becomes too small. On the other hand, if the ratio is too large, the gas from the upper and lower nozzles collides at the part deviated from the steel strip edge, causing gas turbulence, and this gas turbulence causes an excessive amount of siliconization at the edge portion. Conceivable.

Further, as a result of further study on the problem that the edge portion is excessively siliconized by such a turbulent flow of gas, the ratio of the nozzle slit length to the steel strip width is defined. In addition, it is important to regulate the passage position of the steel strip edge on the gas supply side of each slit nozzle in order to suppress the variation of the Si amount in the steel strip width direction and obtain a uniform siliconization amount in the strip width direction. Was found.

The direction of the gas flow supplied from each nozzle slit is as shown in FIG. 3, and the gas flow when the gas is sprayed from the upper and lower slit nozzles to the steel strip is as shown in FIG. Here, in the case where the edge portion of the steel strip has passed a position closer to the inner side in the slit longitudinal direction (closer to the slit end 22) with respect to the slit end 21 on the gas supply side,
Gas blown from above and below collides on the outside of the edge to cause gas turbulence, and the turbulence of the gas causes excessive silicidation of the edge portion. On the other hand, on the slit end 22 side,
Since the gas flow is directed to the outside, the gas escapes to the outside of the nozzle, and the above problem of excessive siliconization due to gas turbulence does not occur. Further, when the edge portion of the steel strip passes the position outside the slit end 21, the amount of gas supplied to the edge portion is too small, and a sufficient amount of siliconization cannot be obtained.

Therefore, from the above, it is most preferable to pass the steel strip so that one edge portion of the steel strip and the slit end 21 on the gas supply side are aligned with each other.
Further, as a result of the experiments by the present inventors, between the slit end 21 and the position where a distance corresponding to approximately 5% of the steel strip width is set in the slit inner direction (slit end 22 direction). It has been found that passing the steel strip edge portion can suppress excessive siliconization of the edge portion due to gas turbulence. Therefore, one edge of the steel strip passes between the slit end 21 on the gas supply side and a position spaced from the slit end 21 toward the other end of the slit by a distance corresponding to 5% of the width of the steel strip. It is preferable to pass through.

By carrying out the siliconizing treatment by such a method, it is possible to prevent a defective shape at the edge of the steel strip and to obtain a plate thickness of 0.05 to 0.5 mm with a uniform Si amount in the plate width direction.
A high silicon steel strip having a plate width of about 100 to 1800 mm can be continuously and stably manufactured.

The steel plate used as a raw material (original plate) in the method of the present invention is generally a plain steel plate or a relatively low Si.
It is a non-oriented or grain-oriented silicon steel sheet with a content (usually Si: 4 wt% or less). The composition of such a raw steel sheet is not particularly limited, but it is preferable to define as follows in order to obtain excellent magnetic properties.

First, the non-metal element will be described. C: C lowers the initial permeability and the maximum permeability, increases Hc, and increases iron loss. It is known that this effect becomes remarkable when it exceeds 0.01 wt% as shown in FIG. 9, and therefore C is preferably 0.01 wt% or less. However, in order to improve the crystal orientation, it is possible to contain C in an amount of more than 0.01 wt% at the steelmaking stage and then roll it. In this case, decarburization annealing is performed to prevent aging and deterioration of properties. However, it is preferable that C be 0.01 wt% or less. That is, the adjustment of the C concentration may be performed in the melting stage, or may be performed by performing decarburization annealing.

O: O is known as an element which enhances iron loss and, when present as colloidal fine particles such as SiO ₂ , significantly deteriorates magnetic properties. Also, O is C
The magnetic characteristics are changed depending on the degree of coexistence with. In particular, as shown in FIG. 10, it is also known that the iron loss value becomes the minimum when the O content and the C content are substantially equal to each other, and the O content is similar to the appropriate range of the C content. Is 0.
It is preferable to set it to 01 wt% or less.

N and S: Since both cause aging, it is preferable to reduce them as much as possible.
It is preferable to set it to 01 wt% or less. P: P has a function of reducing magnetic deterioration due to oxygen and reducing iron loss, and may be added a little for the purpose of improving the maximum magnetic permeability and the magnetic flux density, but the upper limit of the amount added Is up to about 1 wt%. H: H makes the steel sheet extremely brittle, so aggressive inclusion such as inclusion of H under high pressure should be avoided (usually p
below the pm level). As described above, with respect to the non-metal element, it is preferable to suppress C, O, N, S and the like as low as possible and optimize the ratio of C and O.

Next, the metal element will be described. Mn: M in consideration of improvement of ductility at the time of hot rolling and improvement of magnetism in desulfurization action and order-disorder transformation.
It is preferable to add n in the range of 0.5 wt% or less. Ca: When Ca is contained in a large amount, the magnetic permeability decreases, so it is preferably 0.3 wt% or less. V: It is known that Hc is improved by adding a slight amount of V. That is, by adding about 0.05 wt% of V, the development of crystal grains is promoted and the magnetism is improved. Therefore, V can be added with an upper limit of 0.1 wt%.

By adding about 0.05 wt% of Ti, the same effect as V can be expected, so that 0.1 wt% can be added as an upper limit. Be, As: A slight magnetic property improving effect can be expected, and 0.1 wt% of each can be added as an upper limit. Cu: Up to about 0.7 wt%, the magnetism is not significantly deteriorated, but if it exceeds 0.7 wt%, iron loss increases. Therefore, Cu is preferably 0.7 wt% or less, more preferably 0.1 wt% or less. Cr: Iron loss tends to increase, and it is preferably 0.03 wt% or less. Ni: The magnetic properties are significantly deteriorated, so it is preferable to reduce Ni as much as possible, and it is preferable to set it to 0.01 wt% or less.

Al: In the conventional silicon steel sheet, Si is used by utilizing the effect of increasing the electric resistance of Al and the effect of improving the ductility.
The part of Al is replaced with Al. For example,
Instead of 4 wt% Si, Si is set to 3 wt% and Al is set to 1 wt% to maintain workability. In the method of the present invention, since the Si content can be 6.5 wt% or more, it is not necessary to newly add Al for improving the magnetism, and from the viewpoint of promoting deoxidation and improving the spreadability in the melting stage, It is preferable to set it to 0.5 wt% or less.

Further, the diffusion process of Si is performed by Ar, He, H ₂
In a non-oxidizing atmosphere such as above, there is no particular problem even if Al is contained in the above amount. However,
When performing the treatment in an atmosphere containing N ₂ , Al nitrides due to the high temperature treatment, and when the cooling condition is not appropriate,
In the cooling process, AlN detrimental to magnetic properties is deposited. Therefore, when the treatment is performed in an atmosphere containing N ₂ , Al is preferably 80 ppm or less from the viewpoint of preventing precipitation of AlN as much as possible.

In addition to the above elements, the addition of other elements for the following purposes does not impair the effects of the present invention. -Crystal grain growth suppressing element: Se, Sb, Sn, Bi, B,
Te, Mo, Ta, Zr, Nb, etc. ・ Crystal orientation improving element: B, Co, Mo, W, etc. ・ Mechanical property improving element Workability improvement: Mo, W, Co, etc. strength improvement: W, Mo, Co, Be, B, Nb, Ta,
Zr, Hf, etc.

[0030]

【Example】

[Example 1] In a horizontal pass manufacturing line as shown in FIG. 11, a slit nozzle having a slit of 5 mm width formed in a ceramic cylindrical pipe (80 mmφ) as shown in FIG. A high silicon steel strip manufacturing test was conducted using a siliconizing furnace in which four rows were incorporated. In this test, [nozzle slit length] / [steel strip width]
The ratio was set to 1.2, and the gas was supplied to the slit nozzle from the end on one side of the nozzle, and was also changed from the side of the end alternately different for each nozzle in the pass line direction. Also,
The siliconizing treatment was performed such that one edge of the steel strip passed through the gas supply side end of each nozzle slit.
As a material steel strip, plate thickness 0.1 mm x plate width 200 mm,
Plate thickness 0.3 mm x plate width 200 mm, and plate thickness 0.3 m
Using a 3% Si steel strip having a width of m and a plate width of 360 mm, a 6.5% Si steel strip was obtained by a siliconizing treatment.

Other manufacturing conditions are as follows. Reaction gas: Mixed gas of silicon tetrachloride and nitrogen (concentration of silicon tetrachloride 5 to 15 vol%) Gas flow rate per nozzle: 1.5 to 2.5 Nm ³ / h Reactant gas blowing flow rate: 2 to 4 m / s Reacting gas spraying angle: The distribution of the Si amount in the plate width direction of the high silicon steel strip manufactured perpendicular to the steel strip or inclined 30 ° from the vertical is shown in FIGS. 13 to 15.

For comparison, the slit length is 500 m.
m slit nozzle is used under the same conditions as the above test,
Plate thickness 0.3 mm x plate width 200 mm and plate thickness 0.3 mm
4. A 3% Si steel strip having a plate width of 360 mm is used as a raw material steel strip.
A production test of 5 to 6.5% Si steel strip was conducted. In this test, the center of the steel strip and the center of the nozzle slit were almost aligned with each other, and the siliconizing treatment was performed. The ratio of [nozzle slit length] / [steel strip width] is 2.5 for plate width 200 mm and plate width 360 m
It was 1.39 for m material. FIG. 16 shows the distribution of Si content in the plate width direction of the manufactured high silicon steel strip.

As is clear from the above results, FIG.
In the steel strip obtained by the method of the present invention shown in FIG. 15 to FIG. 15, the variation of the Si amount in the plate width direction is suppressed to ± 0.1 wt% or less. On the other hand, in the comparative example shown in FIG. 16, the variation of the Si amount in the plate width direction is ± 0.3 w.
Since it is t% or more, a uniform Si amount is not obtained in the plate width direction.

As the reaction gas for the siliconizing treatment, a mixed gas of silicon tetrachloride and an inert gas (N ₂ , Ar, etc.) is usually used, but the Si compound is limited to the above silicon tetrachloride. Not a thing.

[Embodiment 2] In a horizontal pass production line as shown in FIG. 11, a slit nozzle having a slit of 5 mm width formed in a ceramic cylindrical pipe as shown in FIG. A high silicon steel strip manufacturing test was conducted using the siliconizing furnace equipped with 8 rows. In this test, the ratio of [nozzle slit length] / [steel strip width] was set to 1.2, and the gas was supplied to the slit nozzle from the end on one side of the nozzle, and it was alternated for each nozzle in the pass line direction. It went from the different end side. Further, the siliconizing treatment was performed such that one edge portion of the steel strip passed through the gas supply side end position of each nozzle slit. As the material steel strip, plate thickness 0.1 mm x plate width 200 mm, plate thickness 0.1 mm x plate width 360 mm, and plate thickness 0.3 mm
B. A 3% Si steel strip having a plate width of 360 mm was used to obtain a 6.5% Si steel sheet by a siliconizing treatment. The other manufacturing conditions are the same as in Example 1.

The distribution of the amount of Si in the width direction of the produced high silicon steel strip is shown in FIGS. 17 to 19. It can be seen that by performing the siliconizing treatment under the conditions of the present invention, the variation in the Si amount is suppressed to about ± 0.07% at the maximum.

[Embodiment 3] In a horizontal pass manufacturing line as shown in FIG. 11, a slit nozzle having a slit of 5 mm width formed in a ceramic cylindrical pipe as shown in FIG. A high silicon steel strip manufacturing test was carried out using a siliconizing furnace equipped with four rows. In this manufacturing test, plate thickness 0.3 mm x plate width 300 m
A 3% Si steel strip of m was used as a raw material steel strip to manufacture a 6.5% Si steel sheet. At that time, the slit length of the slit nozzle was changed in the range of 280 to 450 mm, and the strip width direction in each case was changed. The variation of Si amount was investigated. As in each of the above-described examples, the gas was supplied to the slit nozzle from one end on one side of the nozzle, and from the side of the end alternately different for each nozzle in the pass line direction. Further, the siliconizing treatment was performed so that one edge portion of the steel strip passed through the gas supply side end position of each nozzle slit. Other manufacturing conditions are the same as in Example 1.

FIG. 20 shows the variation width of Si amount in the plate width direction of the manufactured high silicon steel strip, arranged by [nozzle slit length] / [steel strip width]. According to this, high-silicon steel in which [nozzle slit length] / [steel band width] is in the range of 1.05 to 1.4, preferably 1.1 to 1.25, and the amount of Si in the width direction is extremely uniform. It turns out that the belt can be manufactured.

[0039]

According to the present invention described above, S in the sheet width direction is obtained by the continuous siliconizing treatment of the steel strip by the continuous line.
It is possible to stably manufacture a high silicon steel sheet having a uniform i amount distribution and a good plate shape.

[Brief description of drawings]

FIG. 1 is a perspective view showing a pair of upper and lower slit nozzles used in the method of the present invention.

FIG. 2 is a sectional view of the slit nozzle shown in FIG.

FIG. 3 is an explanatory diagram showing a velocity ratio and a blowing direction of gas supplied from a slit nozzle.

FIG. 4 is a graph showing the Si amount distribution in the width direction of a steel strip subjected to siliconizing treatment with one slit nozzle.

FIG. 5 is a plan view showing the arrangement of slit nozzles used for carrying out the method of the present invention and the gas supply direction.

6 is a sectional view of the slit nozzle group shown in FIG.

FIG. 7 is a graph showing the relationship between [nozzle slit length] / [steel strip width] and the Si amount variation width in the steel strip width direction.

FIG. 8 is an explanatory view showing a gas spraying situation from the upper and lower slit nozzles to the steel strip.

FIG. 9 is a graph showing the effect of the content of impurity elements in a high silicon steel sheet on iron loss.

FIG. 10 is a graph showing the effect of [carbon content-oxygen content] of high silicon steel sheet on iron loss.

FIG. 11 is an explanatory diagram showing a continuous production line used in Examples.

FIG. 12 is an explanatory view showing the shape of the slit nozzle used in the examples.

FIG. 13 is a graph showing fluctuations in the amount of Si in the plate width direction of the high silicon steel strip manufactured in Example 1.

FIG. 14 is a graph showing variations in the amount of Si in the plate width direction of the high silicon steel strip manufactured in Example 1.

FIG. 15 is a graph showing variations in the amount of Si in the plate width direction of the high silicon steel strip manufactured in Example 1.

FIG. 16 is a graph showing variations in the amount of Si in the plate width direction of the high silicon steel strip manufactured in Example 1.

FIG. 17 is a graph showing variations in the amount of Si in the plate width direction of the high silicon steel strip manufactured in Example 2.

FIG. 18 is a graph showing fluctuations in the Si amount in the plate width direction of the high silicon steel strip manufactured in Example 2.

FIG. 19 is a graph showing variations in the amount of Si in the plate width direction of the high silicon steel strip manufactured in Example 2.

FIG. 20 [nozzle slit length] / in Example 3
Graph showing the relationship between [steel strip width] and the width of variation of Si amount in the width direction of the manufactured high-silicon steel strip

[Explanation of symbols]

1 ... Slit nozzle, 2 ... Nozzle slit, 21, 22
… Slit edge

Claims (2)

[Claims] 1. A method for producing a high-silicon steel strip by subjecting a steel strip to a siliconizing treatment for infiltrating Si from its surface in a reactor and diffusing this Si in the plate thickness direction, the method comprising the steps of: A plurality of slit nozzles are arranged facing each other in the longitudinal direction of the furnace so as to face the back surface, and a plurality of reaction gas is supplied to each slit nozzle from one end thereof, and a plurality of slit nozzles are arranged in the longitudinal direction of the furnace. The method for producing a high-silicon steel strip in a continuous line, characterized in that the above-mentioned reaction gas is alternately supplied to the slit nozzles from different end sides, and the reaction gas is sprayed from the slit nozzles to the front and back surfaces of the steel strip. 2. [Nozzle slit length] / [steel band width]:
1.05 to 1.4 slit nozzles are used, and for each slit nozzle, one edge of the steel strip is 5% of the width of the steel strip from the slit end on the gas supply side to the other end of the slit. The steel strip is passed so as to pass through a position corresponding to the distance, and the gas is sprayed to the steel strip by each of the slit nozzles. Method for manufacturing high silicon steel strip.