Treatment facility of steel material, manufacturing facility of steel material, treatment method of steel material, and manufacturing method of steel material

Abstract

To reduce a variation in a concentration of an element compared to that in a prior art when a property of a steel material is changed by supplying a raw material gas to a surface of the steel material, the variation being attributed to the raw material gas.SOLUTION: One or two slit nozzles arranged such that an axial direction is parallel to a surface of a steel material transported and is vertical to a direction of transporting the steel material are used to spray a raw material gas to a surface of the steel material transported. A slit nozzle is used, a slit profile of the slit nozzle varying depending on a position in an axial direction of the slit nozzle. Preferably a slit angle or an opening area varies depending on a position in the axial direction of the slit nozzle.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a steel processing facility, a steel manufacturing facility, a steel processing method, and a steel manufacturing method. [Background technology]

[0002] Electrical steel sheets are functional materials primarily used in the iron cores of electrical equipment. Silicon (Si) in electrical steel sheets increases electrical resistance, thereby reducing iron loss due to eddy currents generated on the surface of the sheet. In particular, electrical steel sheets containing 6.5% Si by mass are known to exhibit excellent magnetic properties, with nearly zero magnetostriction and a peak in maximum permeability. However, cold rolling becomes difficult when the Si content exceeds 4.0% by mass. To address this issue, Patent Document 1 describes a method for cold-rolling electrical steel sheets containing 4.0% or less Si, followed by siliconizing, which uniformly diffuses Si from the surface to the interior. This method increases the Si content to 6.5% by mass. Patent Document 2 describes a method for creating a Si concentration gradient of 0.5% by mass or more through the thickness of the sheet by performing an appropriate diffusion process on the silicon enriched on the surface of the sheet by siliconizing.

[0003] The methods described in these patent documents use silicon tetrachloride gas as the raw material gas. Variations in the supply rate of silicon tetrachloride gas depending on the widthwise position of the steel sheet result in a problem of Si concentration in the final product varying depending on the widthwise position. To solve this problem, Patent Document 3 describes a method for reducing the variation in the blowing angle of the raw material gas relative to the longitudinal direction of the slit nozzle when the raw material gas is sprayed onto the surface of the steel sheet from a slit nozzle arranged parallel to the widthwise direction of the steel sheet by setting the ratio of the opening area of the slit to the cross-sectional area of the gas flow path inside the slit to a specific value or less. Patent Document 4 describes a method for reducing the variation in the flow rate of the raw material gas sprayed onto the surface of the steel sheet from the slit nozzle by installing a flow straightening plate that partially blocks the gap between the inner and outer tubes of a double-tube slit nozzle to obstruct the flow of the raw material gas. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 62-227078 [Patent Document 2] Japanese Patent Application Publication No. 9-184051 [Patent Document 3] Japanese Patent Application Publication No. 8-176793 [Patent Document 4] International Publication No. 2020 / 084873 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, in both of the inventions described in Patent Documents 3 and 4, the slit nozzles are designed based on the design concept of minimizing the change in the amount of source gas supplied per unit time from the slit nozzle toward the surface of the steel sheet, regardless of the position in the axial direction of the slit nozzle. However, the inventors' analysis revealed that when source gas is supplied using a slit nozzle equipped with slits designed based on the above design concept, there is a limit to the effectiveness of reducing the variation in Si concentration in the width direction of the steel sheet, i.e., in the direction perpendicular to the conveying direction of the steel sheet. For example, it was extremely difficult with conventional technology to control the variation in Si concentration in the direction perpendicular to the conveying direction of the steel sheet to within a range of 6.5±0.1 mass%.

[0006] The present invention has been made in view of the above-mentioned problems, and aims to reduce the variation in the concentration of elements caused by the raw material gas in a direction perpendicular to the direction in which the steel material is transported, compared to that of conventional technology, when modifying the steel material by supplying the raw material gas. [Means for solving the problem]

[0007] The gist and configuration of the present invention are as follows. [1] A steel treatment facility for modifying steel by supplying a raw material gas to the surface of the steel, a conveying means for conveying the steel material; one or more slit nozzles that spray the raw material gas toward the surface of the steel material transported by the transport means, The slit nozzle is provided so that its axial direction is parallel to the surface of the steel material and perpendicular to the direction in which the steel material is conveyed, The shape of the slit of the slit nozzle varies depending on the position in the axial direction of the slit nozzle. Steel processing equipment. [2] In a cross section perpendicular to the axial direction of the slit nozzle, the angle formed by a perpendicular line drawn from the center of the slit nozzle to the surface of the steel material and a line segment connecting the center of the slit nozzle and the center of the slit varies depending on the position in the axial direction of the slit nozzle. [1] Steel processing equipment. [3] The opening area of the slit per unit length as viewed in the axial direction of the slit nozzle varies depending on the position in the axial direction of the slit nozzle. [1] or [2] Steel processing equipment. [4] The total length of the slits per unit length as viewed in the axial direction of the slit nozzle varies depending on the position in the axial direction of the slit nozzle. [3] Steel processing equipment. [5] The width of the slit varies depending on the position in the axial direction of the slit nozzle; [3] Steel processing equipment. [6] Further provided is a heating means for heating the steel material transported by the transport means. [1] to [5] Steel processing equipment according to any one of the items. [7] The modification is siliconizing treatment; [1] to [5] Steel processing equipment according to any one of the items. [8] [1] to [5], equipped with a steel processing facility described in any one of [1] to [5], Steel manufacturing equipment. [9] A method for treating steel material, which modifies the steel material by supplying a raw material gas to the surface of the steel material, The method includes a step of spraying the raw material gas toward a surface of the steel material being transported using one or more slit nozzles, The slit nozzle is provided so that its axial direction is parallel to the surface of the steel material and perpendicular to the direction in which the steel material is conveyed, The shape of the slit of the slit nozzle varies depending on the position in the axial direction of the slit nozzle. How steel is processed.

[10] A step of heating the steel material before and / or after the step of blowing the raw material gas is provided. [9] A method for treating steel materials according to the present invention.

[11] The modification is siliconizing treatment; [9] A method for treating steel materials according to the present invention.

[12] Modifying steel using the steel treatment method according to any one of [9] to

[11] ; Steel manufacturing method. [Effects of the Invention]

[0008] According to the present invention, in a steel material modified by supplying a raw material gas, the variation in the concentration of elements caused by the raw material gas in a direction perpendicular to the direction in which the steel material is transported can be reduced more than in the case of the prior art. This makes it possible to make the quality of the entire steel material uniform and reduce deflection of the steel material caused by the variation in concentration. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing an example of steel processing equipment according to the present invention. [Figure 2] 1 is a cross-sectional view showing an example of steel processing equipment according to the present invention. [Figure 3] FIG. 1 is a perspective view showing an example of a slit nozzle according to a first embodiment of the present invention. [Figure 4] FIG. 3 is a perspective view showing another example of the slit nozzle according to the first embodiment of the present invention. [Figure 5] FIG. 10 is a perspective view showing an example of a slit nozzle according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a perspective view showing another example of the slit nozzle according to the second embodiment of the present invention. [Figure 7] 4 is a graph showing the distribution of Si concentration in Example 1 of the present invention. [Figure 8] 10 is a graph showing the distribution of Si concentration in Example 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail.

[0011] <Steel processing equipment> (1) Basic structure of the invention In one embodiment, the present invention provides a method for producing a medicament for the treatment of a pulmonary arthritis. A steel material treatment facility that modifies steel material by supplying a raw material gas to a surface of the steel material, a conveying means for conveying the steel material; one or more slit nozzles that spray the raw material gas toward the surface of the steel material transported by the transport means, The slit nozzle is provided so that its axial direction is parallel to the surface of the steel material and perpendicular to the direction in which the steel material is conveyed, The shape of the slit of the slit nozzle varies depending on the position in the axial direction of the slit nozzle. This is an invention for steel processing equipment.

[0012] The steel material modification performed by the steel material treatment equipment according to the present invention may be any modification performed by supplying a raw material gas to the surface of the steel material. In the present invention, the term "raw material gas" refers to a gas in which at least one element contained in the raw material gas remains on the surface of the steel material after modification. The element derived from the raw material gas may remain only on the surface of the steel material after modification, or may diffuse from the surface to the interior of the steel material. Among the steel material modifications using a raw material gas, a specific example of a modification that modifies only the surface of the steel material is the formation of a titanium nitride coating by chemical vapor deposition. Furthermore, a specific example of a modification that involves diffusion from the surface to the interior of the steel material is the siliconizing process described below.

[0013] 1 is a perspective view showing an example of a steel material treatment facility according to the present invention. The steel material treatment facility 1 according to the present invention modifies the steel material 4 by supplying a raw material gas to the surface of the steel material 4.

[0014] The steel material processing equipment 1 according to the present invention includes a conveying means (not shown) for conveying the steel material 4. The conveying means is a means for moving the steel material 4 relatively to the slit nozzle 2 (described later) in the conveying direction indicated by the arrow in Fig. 1. The conveying means can be constituted by a conveying roll, a conveyor, or other known means.

[0015] The steel material processing equipment 1 according to the present invention includes one or more slit nozzles 2 that spray raw material gas toward the surface of the steel material 4 being transported by a transport means. As shown in FIG. 1 , the axial direction of the slit nozzle 2 is parallel to the surface of the steel material 4 and perpendicular to the direction of transport of the steel material 4 indicated by the arrow, i.e., the x-axis. This allows the slit nozzle 2 to spray raw material gas evenly in a direction perpendicular to the direction of transport of the steel material 4, i.e., the y-axis. Here, the axial direction of the slit nozzle 2 refers to the longitudinal direction of the slit nozzle 2. The axial direction of the slit nozzle 2 does not need to be strictly parallel to the surface of the steel material 4 or strictly perpendicular to the direction of transport of the steel material; it may be deviated in a direction that does not impair the function of spraying raw material gas evenly. In other words, the axial direction of the slit nozzle 2 may be deviated from the y-axis by up to 10 degrees.

[0016] The cross-sectional shape of the slit nozzle 2 may be any shape as long as it allows the raw material gas to flow inside and the raw material gas to be sprayed from the slit 3 described below toward the surface of the steel material 4 being transported. The shape of the slit nozzle 2 is preferably a cylindrical shape as exemplified in FIG. 1. The length of the slit nozzle 2 is preferably longer than the width of the steel material 4. The structure of the slit nozzle 2 may be a double-tube structure consisting of an inner tube and an outer tube, like the slit nozzle described in Patent Document 4.

[0017] The number of slit nozzles 2 provided in the steel material processing equipment 1 according to the present invention may be one, as exemplified in Fig. 1, or may be two or more. When multiple slit nozzles 2 are provided, the total amount of source gas supplied to one surface of the steel material 4 can be increased by arranging multiple slit nozzles 2 side by side on that surface. Alternatively, by arranging multiple slit nozzles 2 on each of the opposing surfaces of the steel material 4, the source gas can be supplied to two surfaces of the steel material 4 simultaneously.

[0018] In the steel processing equipment 1 according to the present invention, the shape of the slit 3 of the slit nozzle 2 varies depending on the position in the axial direction of the slit nozzle 2. As shown in FIG. 1, the slit 3 of the slit nozzle 2 is a long, narrow hole provided along the axial direction of the slit nozzle 2. The raw material gas passes through the gaps in the slit 3 and is blown from the inside to the outside of the slit nozzle 2. This causes the raw material gas to be blown toward the surface of the steel 4. The slit 3 of one slit nozzle 2 may be a single slit 3 provided continuously in the length direction of the slit nozzle 1, or multiple slits 3 may be provided intermittently in the axial direction.

[0019] The shape of the slit 3 in the slit nozzle 2 affects the supply rate per unit time of the source gas sprayed onto the surface of the steel material 4 during transportation, the spray angle of the source gas, and other factors. In conventional steel material processing equipment, the shape of the slit 3 does not change depending on the axial position of the slit nozzle 2, as shown in the example of slit 3' in Figure 1 . That is, the width of the slit 3' and the spray angle are constant. When siliconizing steel material 4 using such steel material processing equipment, the Si concentration sometimes varies depending on the position in the direction perpendicular to the transport direction of the steel material 4. Specifically, when analyzing the Si concentration on the surface of the center portion 4a, quarter portions 4b, and end portions 4c of the steel material 4 shown in Figure 1, the Si concentration at the end portions 4c was sometimes higher than that at the center portion 4a, or conversely, the Si concentration at the end portions 4c was sometimes lower than that at the center portion 4a. Here, the "quarter portions" refer to the portions corresponding to positions midway between the center portion 4a, which is the center of the steel material 4 in the direction perpendicular to the transport direction, and both ends. Moreover, the "end" refers to a portion corresponding to a position slightly closer to the quarter portion 4b from the end in the direction perpendicular to the direction in which the steel material 4 is transported.

[0020] In the steel material processing apparatus 1 according to the present invention, the shape of the slit 3 of the slit nozzle 2 varies depending on the position in the axial direction of the slit nozzle 2. This makes it possible to change the supply amount per unit time of the raw material gas sprayed toward the surface of the steel material 4 transported by the transport means, the spray angle of the raw material gas, and the like, depending on the position in the direction perpendicular to the direction in which the steel material 4 is transported. As a result, it is possible to suppress variations in the Si concentration on the surface of the central portion 4a, quarter portions 4b, and end portions 4c of the steel material 4.

[0021] In the prior art, the slit nozzle and the slit are designed so that the supply amount per unit time of the raw material gas sprayed from the slit nozzle onto the steel material and the spray angle of the raw material gas do not change depending on the position in the axial direction of the slit nozzle. However, the reason why the above-mentioned variation in Si concentration occurs is not understood in detail, but the inventors generally consider it as follows.

[0022] In the siliconizing process of steel using silicon tetrachloride, silicon tetrachloride undergoes a substitution reaction with the iron contained in the steel, causing Si to penetrate the steel and generating ferric chloride gas as a by-product of the reaction. The generated ferric chloride gas moves with the transport of the steel and remains on the surface of the steel. This prevents unreacted silicon tetrachloride from coming into contact with the surface of the steel.

[0023] On the surface of steel, a complex gas flow is generated by three components: the atmospheric gas inside the treatment equipment, silicon tetrachloride gas sprayed onto the surface of the steel from the slit nozzle, and ferric chloride gas generated from the surface of the steel. This complex gas flow easily changes depending on the type of steel being treated, the condition of the steel surface, and other steel treatment conditions. This is thought to be why a certain trend can be seen in the variation in Si concentration on the surface of steel under certain treatment conditions.

[0024] As described above, the variation in the Si concentration on the surface of a steel material typically exhibits two trends: one where the Si concentration is higher at the end portion 4c than at the center portion 4a, and the other where the Si concentration is lower at the end portion 4c than at the center portion 4a. In the steel material processing device 1 according to the present invention, the shape of the slits 3 of the slit nozzle 2 is changed depending on the position in the axial direction of the slit nozzle 2 so as to counteract such a tendency of variation. This makes it possible to control the variation in the Si concentration in the direction perpendicular to the direction in which the steel material is transported to within a range of 6.5±0.1 mass%, which was extremely difficult with conventional technology.

[0025] The tendency of variation in Si concentration on the surface of a steel material is not limited to the above two types of tendency. For example, it is conceivable that the Si concentration of a wide steel material will show a more complex tendency of variation. Even in such a case, it is possible to suppress the variation in Si concentration in the direction perpendicular to the conveying direction of the steel sheet by changing the shape of the slit 3 according to the tendency of each variation.

[0026] (2) Slit angle In a preferred embodiment, in the steel processing equipment according to the present invention, in a cross section perpendicular to the axial direction of the slit nozzle, the angle formed by a perpendicular line drawn from the center of the slit nozzle to the surface of the steel and a line segment connecting the center of the slit nozzle and the center of the slit varies depending on the position in the axial direction of the slit nozzle.

[0027] FIG. 2 is a cross-sectional view showing an example of steel material processing equipment according to the present invention. FIG. 2 shows a cross-section perpendicular to the axial direction of a slit nozzle 2 provided in steel material processing equipment 1. On this cross-section, the angle formed by a perpendicular line drawn from the center of slit nozzle 2 to the surface of steel material 4 and a line segment connecting the center of slit nozzle 2 and the center of slit 3 is indicated by the symbol θ. Here, the "center of the slit" refers to the center of the width of slit 3 measured in the circumferential direction of the cross-section of slit nozzle 2 shown in FIG. 2. The angle θ is a positive value when it is angled from the direction of the perpendicular line drawn from the center of slit nozzle 2 to the surface of steel material 4 toward the conveying direction of steel material 4 indicated by the arrow.

[0028] The angle θ determines the direction in which the raw material gas is blown out of the slit 3. The closer the absolute value of the angle θ is to zero, the more the raw material gas is blown in a direction closer to perpendicular to the surface of the steel material 4. In this case, the raw material gas blown out of the slit 3 pushes aside other gases present near the surface of the steel material 4, so most of the raw material gas reaches the surface of the steel material 4 and reacts with the steel material 4. When multiple slit nozzles 2 are provided on one surface side of the steel material 4, by-products such as ferric chloride produced by reaction with the raw material gas blown from the upstream slit nozzle 2 move while remaining on the surface of the steel material 4. In this case, too, the raw material gas blown out of the slit 3 in a direction closer to perpendicular to the surface of the steel material 4 pushes aside by-products present near the surface of the steel material 4, so most of the raw material gas contributes to the reaction with the surface of the steel material 4.

[0029] On the other hand, the larger the absolute value of the angle θ, the more the raw material gas is blown obliquely toward the surface of the steel material 4. In this case, the raw material gas blown out from the slit 3 has a weaker force to push away other gases present near the surface of the steel material 4, so that part of the raw material gas cannot reach the surface of the steel material 4 and does not contribute to the reaction with the steel material 4. Similarly, it becomes more difficult to push away by-products generated upstream.

[0030] In this way, by changing the angle θ depending on the position in the axial direction of the slit nozzle, it is possible to control the degree of reaction between the raw material gas supplied from the slit nozzle 2 to the surface of the steel material 4 and the surface of the steel material 4. In steel material processing equipment according to conventional technology, the absolute value of the angle θ is made closer to zero at positions where the degree of reaction is insufficient to promote the reaction, and conversely, the absolute value of the angle θ is made larger at positions where the degree of reaction is excessive to suppress the reaction, thereby making it possible to cause the reaction to occur uniformly in a direction perpendicular to the direction in which the steel material 4 is transported.

[0031] The angle θ may be a positive value as exemplified in Fig. 1, or conversely, it may be a negative value that is an angle that opens in the opposite direction to the conveyance direction of the steel material 4. When the angle θ is a negative value, the flow of the raw material gas sprayed from the slit nozzle 2 toward the surface of the steel material 4 is sprayed against the conveyance direction of the steel material 4, and therefore the flow of the gas containing the raw material gas will be different from when the angle θ is a positive value. However, by changing the absolute value of the angle θ, which is a negative value, depending on the position in the axial direction of the slit nozzle, it is possible to obtain an effect similar to that of the present invention described above.

[0032] The magnitude of the absolute value of the angle θ is preferably 40 degrees or less. If the magnitude of the absolute value of the angle θ is 40 degrees or less, the proportion of the raw material gas that reaches the surface of the steel material 4 does not become too small, and the raw material gas is not wasted. The magnitude of the absolute value of the angle θ is more preferably 30 degrees or less. The minimum value of the absolute value of the angle θ does not need to be particularly limited, and may be 0 degrees.

[0033] Next, specific examples of slit nozzles in which the angle θ varies depending on the position in the axial direction of the slit nozzle will be described. FIG. 3 is a perspective view showing examples of slit nozzles used in Example 1 of the present invention, which will be described later. All three types of slit nozzles 2 shown here are incorporated into the steel material processing apparatus 1 shown in FIG. 1 for use. When the slit nozzle 2 shown in FIG. 3 is incorporated into the steel material processing apparatus 1 shown in FIG. 1, it is incorporated so that the orientations of the x, y, and z orthogonal coordinate axes shown in these figures are aligned. The absolute value of the angle θ of the slit 3 in these slit nozzles 2 is closest to 0 degrees at the center of the slit nozzle 2 in the axial direction and increases toward both ends in the axial direction. This promotes the reaction between the steel material 4 and the source gas at the center 4a of the steel material 4 and suppresses the reaction between the steel material 4 and the source gas at the end 4c of the steel material 4.

[0034] The slit nozzle 2 shown in Figure 3(a) has five discontinuous slits 3 with different absolute values of angle θ. All five slits 3 are arranged in a direction parallel to the central axis of the slit nozzle 2. The absolute value of the angle θ of the five slits 3 is closest to 0 degrees at the center of the axial direction of the slit nozzle 2, is largest at both ends, and is an intermediate value between them.

[0035] The slit nozzle 2 shown in Figure 3(b) has one continuous slit 3. The slit 3 is composed of two linear slits connected at a bent portion located in the axial center of the slit nozzle 2. The absolute value of the angle θ of the slit 3 is closest to 0 degrees at the axial center of the slit nozzle 2, is largest at both ends, and changes continuously between them.

[0036] The slit nozzle 2 shown in Figure 3(c) has one continuous slit 3. The slit 3 is made up of five linear slits connected by bends located at four points. The absolute value of the angle θ of the slit 3 is closest to 0 degrees at the center of the axial direction of the slit nozzle 2, is largest at both ends, and changes continuously between the bends in between.

[0037] The embodiment of the slit nozzle 2 in which the angle θ varies depending on the axial position of the slit nozzle is not limited to the three types of shapes exemplified in FIG. 3, and may be any shape.

[0038] (3) Slit opening area In a preferred embodiment, in the steel processing equipment according to the present invention, the opening area of the slit per unit length as viewed in the axial direction of the slit nozzle varies depending on the position in the axial direction of the slit nozzle.

[0039] When the pressure of the source gas inside the slit nozzle 2 is sufficiently high and a sufficient amount of source gas is supplied to the slit nozzle 2 so that the pressure does not decrease, the pressure of the source gas inside the slit nozzle 2 is kept approximately constant at any position. In this case, the amount of source gas supplied per unit time that is sprayed from the slit nozzle 2 toward the surface of the steel material 4 is proportional to the opening area of the slit 3.

[0040] In conventional steel processing equipment, the width of the slit does not change depending on the position in the axial direction of the slit nozzle 2, as in the case of the slit 3' illustrated in FIG. 1. In this case, the opening area of the slit 3' per unit length as viewed in the axial direction of the slit nozzle 2 does not change depending on the position in the axial direction of the slit nozzle 2. Here, the "slit opening area per unit length as viewed in the axial direction of the slit nozzle 2" refers to the total area of the slit openings included in a portion of a unit length measured in the axial direction of the slit nozzle 2, i.e., the y-axis direction, for the slit nozzle 2 shown in FIG. 1. The unit length may be, for example, 1 centimeter. In the slit 3' of the conventional technology, the opening area of the slit per unit length is constant regardless of the portion of the slit nozzle 2 taken in the axial direction.

[0041] On the other hand, in a preferred embodiment, the opening area of the slit 3 per unit length as viewed in the axial direction of the slit nozzle 2 varies depending on the position in the axial direction of the slit nozzle 2. In this way, by changing the opening area depending on the position in the axial direction of the slit nozzle, it is possible to control the degree of reaction between the raw material gas supplied from the slit nozzle 2 to the surface of the steel material 4 and the surface of the steel material 4. In steel processing equipment according to the prior art, the opening area was increased at positions where the degree of reaction was insufficient to promote the reaction, and conversely, the opening area was decreased at positions where the degree of reaction was excessive to suppress the reaction, thereby making it possible to cause the reaction to occur uniformly in a direction perpendicular to the direction in which the steel material 4 is transported.

[0042] Next, a specific example of a slit nozzle in which the slit opening area per unit length as viewed in the axial direction of the slit nozzle varies depending on the position in the axial direction of the slit nozzle will be described. FIG. 4 is a perspective view showing another example of a slit nozzle used in Example 1 of the present invention, which will be described later. The opening area of the slit 3 per unit length as viewed in the axial direction of the two types of slit nozzles 2 shown here is largest at the center of the slit nozzle 2 in the axial direction and becomes smaller as it approaches both ends in the axial direction. This promotes the reaction between the steel material 4 and the source gas in the center portion 4a of the steel material 4 and suppresses the reaction between the steel material 4 and the source gas at the ends 4c of the steel material 4.

[0043] In a more preferred embodiment, in the steel processing equipment according to the present invention, the total length of the slits per unit length as viewed in the axial direction of the slit nozzle varies depending on the position in the axial direction of the slit nozzle. The slit nozzle 2 shown in FIG. 4(a) has nine discontinuous slits 3 of varying lengths but with a constant width and angle θ. All nine slits 3 are arranged parallel to the axial direction of the slit nozzle 2. Of the nine slits 3, the one slit 3 located in the center of the slit nozzle 2 in the axial direction is the longest, the two slits located at both ends are the shortest, and the lengths of the two slits located between them are intermediate between them. As a result, the total length of the slits 3 per unit length as viewed in the axial direction of the slit nozzle 2 is greatest at the center and decreases toward both ends.

[0044] In a more preferred embodiment, in the steel material processing device according to the present invention, the width of the slit varies depending on the position in the axial direction of the slit nozzle. The slit nozzle 2 shown in Figure 4(b) has one slit 3 with a constant angle θ. The slit 3 is composed of five continuous sections with different widths. The width of the slit 3 is widest at the center of the slit nozzle 2 in the axial direction, narrowest at both ends, and intermediate between them.

[0045] The embodiment of the slit nozzle 2 in which the opening area of the slit per unit length as viewed in the axial direction of the slit nozzle varies depending on the position in the axial direction of the slit nozzle is not limited to the two types of forms exemplified in Figure 4, and may be any form.

[0046] (4) Other embodiments of the slit nozzle The above-described specific examples of the slit nozzle 2 according to the present invention all have the effect of promoting the reaction in the central portion 4a of the steel material and suppressing the reaction at the edges 4c. Conversely, if it is desired to suppress the reaction in the central portion 4a of the steel material and promote the reaction at the edges 4c, a slit nozzle 2 having a different configuration of the slit 3 from the above specific examples can be used. FIG. 5 is a perspective view showing an example of a slit nozzle used in Example 2 of the present invention, which will be described later. The three types of slit nozzles 2 shown in FIGS. 5(a), 5(b), and 5(c) have configurations similar to the three types of slit nozzles 2 shown in FIGS. 3(a), 3(b), and 3(c), respectively. In contrast to the slit nozzle 2 shown in FIG. 3, the absolute value of the angle θ of the slit nozzle 2 shown in FIG. 5 is largest at the center of the axial direction of the slit nozzle 2, closest to 0 at both ends, and intermediate between them.

[0047] Similarly, Figure 6 is a perspective view showing another example of a slit nozzle used in Example 2 of the present invention, which will be described later. The two types of slit nozzles 2 shown in Figures 6(a) and 6(b) have configurations similar to the two types of slit nozzles 2 shown in Figures 4(a) and 4(b), respectively. The slit nozzle 2 shown in Figure 6 is the opposite of the slit nozzle 2 shown in Figure 4, in that the opening area of the slit 3 per unit length viewed in the axial direction of the slit nozzle 2 is largest at the center of the slit nozzle 2 in the axial direction, is closest to 0 at both ends, and is an intermediate value between them.

[0048] The configurations of the slits 3 in these other specific examples of the slit nozzle 2 shown in Figures 5 and 6 and the effects of the present invention brought about by those configurations are no different from the configurations of the slits 3 described in Figures 3 and 4, except for the order in which the slits 3 are arranged in the axial direction of the slit nozzle 2. Therefore, a detailed description of the configurations of the slit nozzle 2 shown in Figures 5 and 6 and the effects of the present invention brought about by those configurations will be omitted here.

[0049] Next, a combination of multiple preferred embodiments of the slit nozzle 2 will be described. As described above, in a preferred embodiment of the present invention, the degree of reaction between the steel material 4 and the source gas is controlled by changing the angle θ of the slit 3 or the opening area of the slit 3 per unit length as viewed in the axial direction of the slit nozzle 2 depending on the position in the axial direction of the slit nozzle. When the degree of non-uniformity of the reaction in the prior art is small, it is sufficient to control the degree of reaction using any of the above configurations. However, for example, when the non-uniformity of the reaction must be significantly corrected, both the angle θ of the slit 3 and the opening area of the slit 3 per unit length of the slit nozzle 2 may be changed simultaneously. The present invention does not exclude such embodiments, regardless of the purpose.

[0050] (5)Heating means In a preferred embodiment, the steel material processing facility according to the present invention further comprises heating means for heating the steel material transported by the transport means.

[0051] The reaction between the steel material and the raw material gas can be promoted by using a heating means to preheat the temperature of the steel material onto whose surface the raw material gas is sprayed. When the steel material is treated by siliconizing, heating the steel material promotes the substitution reaction on the surface of the steel material and the diffusion of the supplied Si into the steel material. Known heat sources such as electric heaters and fuel combustion can be used as the heat source used in the heating means. The steel material treatment equipment according to the present invention may also be equipped with a cooling means in addition to the heating means.

[0052] (6) Siliconizing treatment In a preferred embodiment, the steel material processing equipment according to the present invention has the following configuration in addition to the above: The modification is a siliconizing treatment.

[0053] As described above, in siliconizing treatment using silicon tetrachloride as a raw material gas, silicon tetrachloride undergoes a substitution reaction with iron contained in the steel material, causing Si to penetrate the steel material. This increases the Si concentration in the steel material. In siliconizing treatment, ferric chloride gas is generated as a by-product. If the generated ferric chloride gas remains on the surface of the steel material, it can interfere with the substitution reaction between silicon tetrachloride and iron, and the Si concentration in the final product may vary depending on the position in the direction perpendicular to the direction in which the steel material is transported. In the method for producing steel material according to the present invention, variation in Si concentration can be suppressed by using a slit nozzle whose slit shape varies depending on the position in the axial direction of the slit nozzle.

[0054] In the above-described preferred embodiment, silicon tetrachloride used as the raw material gas may be used alone or in a mixture with another gas. Examples of such other gases include nitrogen gas and argon gas. By using a raw material gas mixture of silicon tetrachloride and another gas, the pressure of the raw material gas inside the slit nozzle can be increased, thereby increasing the supply amount per unit time of the raw material gas sprayed from the slit nozzle toward the surface of the steel material. This displaces ferric chloride remaining on the surface of the steel material, increasing the proportion of silicon tetrachloride that reaches the surface of the steel material and contributes to the substitution reaction, thereby reducing the consumption of silicon tetrachloride required for modifying the steel material.

[0055] When siliconizing treatment using silicon tetrachloride is performed, it is preferable to heat the steel material being transported by the transport means. By increasing the temperature of the steel material onto which the raw material gas containing silicon tetrachloride is sprayed, the substitution reaction is promoted and Si can be smoothly infiltrated into the steel material. In this case, the temperature to which the steel material is heated is preferably 1150°C or higher and 1250°C or lower.

[0056] In a more preferred embodiment, in addition to the above configuration, the method for producing a steel material according to the present invention further comprises heating the steel material to a predetermined temperature after the raw material gas has been sprayed thereon to perform a silicon diffusion treatment.

[0057] As described above, in siliconizing, Si penetrates the surface of a steel material, increasing the Si concentration near the surface of the steel material. By heating the steel material to a predetermined temperature simultaneously with or after siliconizing, Si diffuses from the surface, where the concentration is high, toward the interior, where the concentration is low. If the diffusion is allowed to proceed for a sufficiently long time, the Si concentration becomes uniform throughout the thickness of the steel material, as described in Patent Document 1, for example. If the diffusion is stopped midway, the Si concentration is highest at the surface of the steel material and continuously decreases toward the interior of the steel material, as described in Patent Document 2, for example.

[0058] (7) Analysis means In a preferred embodiment, the steel processing facility according to the present invention further comprises an analysis means for analyzing the content of elements derived from the raw material gas contained in the steel.

[0059] In a preferred embodiment, the analytical means analyzes the surface of the steel material after the spraying of the raw material gas and the reaction between the raw material gas and the steel material are completed in the steel material processing equipment of the present invention. By using the analytical means to analyze at least one of the central portion 4a and two end portions 4c of the steel material surface, the distribution of elements derived from the raw material gas in a direction perpendicular to the direction of transport of the steel material can be determined. It is more preferable if the analysis can also be performed on the quarter portion 4b. It is more preferable that the analytical means can analyze the surface of the steel material being processed in the steel material processing equipment or the steel material after being processed in the steel material processing equipment without stopping the transport of the steel material. This allows for constant monitoring of the quality of the steel material processed in the steel material processing equipment of the present invention. Energy dispersive X-ray fluorescence analysis, for example, can be used as the analytical means.

[0060] <Steel manufacturing equipment> In another embodiment, the present invention provides Equipped with the steel material processing equipment according to the present invention, This is an invention of steel manufacturing equipment.

[0061] The steel manufacturing equipment of the present invention can include not only the conveying means, slit nozzle, and heating means that constitute the processing equipment for modifying the steel, but also equipment associated with these components, as well as coil unwinding devices, winding devices, etc. that are not directly involved in the modification of the steel.

[0062] <Steel manufacturing method> (1) Structure of the invention In another embodiment, the present invention provides A method for manufacturing a steel material in which a raw material gas is supplied to a surface of the steel material to modify the steel material, The method includes a step of spraying the raw material gas toward a surface of the steel material being transported using one or more slit nozzles, The slit nozzle is provided so that its axial direction is parallel to the surface of the steel material and perpendicular to the direction in which the steel material is conveyed, The shape of the slit of the slit nozzle varies depending on the position in the axial direction of the slit nozzle. This is an invention of a method for manufacturing steel.

[0063] In a preferred embodiment, the method for producing a steel material according to the present invention further comprises the steps of: In a cross section perpendicular to the axial direction of the slit nozzle, the angle formed by a perpendicular line drawn from the center of the slit nozzle to the surface of the steel material and a line segment connecting the center of the slit nozzle and the center of the slit varies depending on the position in the axial direction of the slit nozzle.

[0064] In a preferred embodiment, the method for producing a steel material according to the present invention further comprises the steps of: The opening area of the slit per unit length as viewed in the axial direction of the slit nozzle varies depending on the position in the axial direction of the slit nozzle.

[0065] In a more preferred embodiment, the method for producing a steel material according to the present invention further comprises the steps of: The total length of the slits per unit length as viewed in the axial direction of the slit nozzle varies depending on the position in the axial direction of the slit nozzle.

[0066] In a more preferred embodiment, the method for producing a steel material according to the present invention further comprises the steps of: The width of the slit varies depending on the position in the axial direction of the slit nozzle.

[0067] In a preferred embodiment, the method for producing a steel material according to the present invention further comprises the steps of: The method includes a step of heating the steel material before and / or after the step of blowing the raw material gas.

[0068] In a preferred embodiment, the method for producing a steel material according to the present invention further comprises the steps of: The modification is a siliconizing treatment.

[0069] Among the steps constituting the method for producing a steel material according to the present invention, the step of spraying a raw material gas, the step of heating the steel material, and the siliconizing treatment, as well as the effects of the present invention brought about by these steps, are the same as the effects brought about by the configuration of the steel material treatment equipment described above. Therefore, detailed explanations of these steps will be omitted here, and the steel material used in the method for producing a steel material according to the present invention will be described in detail below.

[0070] (2) Steel type and shape The type of steel used in the method for producing a steel material according to the present invention can be selected from a variety of steel types depending on the purpose of modification. For example, if the purpose of modifying the steel material is the siliconizing treatment described in Patent Document 1, the type of steel material may be an electrical steel sheet having an Si content of 4.0 mass% or less. This makes it possible to perform cold rolling of the electrical steel sheet while avoiding the increase in hardness that accompanies an increase in the Si content.

[0071] The shape of the steel material used in the steel material manufacturing method according to the present invention may be any shape as long as it has a surface to which a raw material gas for reforming can be supplied. The shape of the steel material may be, for example, a thick plate as exemplified in FIG. 1, a thin plate having a thickness thinner than the thick plate, a billet having a cylindrical or rectangular prism shape, or a hollow tube. The shape of the steel material is preferably a thick plate or a thin plate. The direction in which the steel material is transported is preferably the in-plane direction when the steel material is a thick plate, the rolling direction when the steel material is a thin plate, or the longitudinal direction when the steel material is a billet or a tube.

[0072] (3)Electromagnetic steel sheet In a further preferred embodiment, in addition to the above configuration, the method for producing a steel material according to the present invention is such that the steel material is an electromagnetic steel sheet.

[0073] As described above, an electrical steel sheet containing 6.5% by mass of Si exhibits excellent magnetic properties, with magnetostriction approaching zero and a peak in maximum magnetic permeability. According to this preferred embodiment, an electrical steel sheet with an Si content of 4.0% by mass or less is cold-rolled, and then siliconized to uniformly diffuse Si from the surface to the interior, thereby increasing the Si content to 6.5% by mass.

[0074] The thickness of the electromagnetic steel sheet is preferably 0.10 mm, for example. In the prior art, when an electromagnetic steel sheet with a thickness of 0.10 mm and a Si concentration of 6.5 mass % was manufactured, the Si concentration varied by up to 0.2 mass % depending on the position in the direction perpendicular to the conveying direction of the electromagnetic steel sheet. Variations in the Si concentration could cause warping of the electromagnetic steel sheet. According to a preferred embodiment, the variation in the Si concentration of the electromagnetic steel sheet depending on the position in the direction perpendicular to the conveying direction of the steel material can be controlled to within 6.5±0.1 mass %. This can suppress warping of the electromagnetic steel sheet, thereby improving the volume fraction when the electromagnetic steel sheet is wound into a core.

[0075] <Steel manufacturing method> In another embodiment, the present invention provides Modifying steel using the steel treatment method of the present invention; This is an invention of a method for manufacturing steel.

[0076] The method for manufacturing steel material according to the present invention can include, in addition to the steps of spraying raw material gas and heating steel material, which constitute a processing method for modifying steel material, steps incidental to these steps, and steps such as unwinding and winding a coil that are not directly related to the modification of steel material. [Example]

[0077] Examples of the present invention will be described below. Note that the embodiments of the present invention are not limited to the following examples and can be modified as desired without departing from the gist of the present invention.

[0078] Example 1 The steel material used was an electrical steel sheet made of steel type A containing 3.3 mass% Si, measuring 600 mm in width and 0.10 mm in thickness. The steel processing equipment used was a steel processing equipment 1 shown in FIG. 1 equipped with a slit nozzle 2 having a slit 3' according to the prior art shown in FIG. 1. The angle θ and width of the slit 3' were constant over the entire length, and the angle θ was a positive value of 20 degrees. Four slit nozzles 2 were installed above the position where the electrical steel sheet was being transported, and four below, at equal intervals, so that the axial direction was parallel to the surface of the electrical steel sheet and perpendicular to the direction in which the electrical steel sheet was being transported.

[0079] Next, the interior of the steel material processing device 1 was filled with nitrogen gas, and the electrical steel sheet was transported at a speed of 24 meters per minute using a transport means in the transport direction indicated by the arrow in Figure 1. The temperature of the electrical steel sheet transported by the transport means was heated to 1200°C using a heating means. A raw material gas consisting of a mixed gas of silicon tetrachloride and nitrogen was sprayed from the eight slit nozzles 2 toward the surface of the heated electrical steel sheet. The supply amount of the raw material gas was adjusted so that the Si concentration in the final product would be 6.5 mass%. Next, the electrical steel sheet after siliconizing treatment was heated to a predetermined temperature to perform a silicon diffusion treatment, and the Si concentrated on the surface was uniformly diffused into the interior, thereby producing the electrical steel sheet of Comparative Example 1.

[0080] Next, the electrical steel sheet of Comparative Example 1 was cooled, and the Si content in the surface of the central portion 4a on the upper surface side, the two quarter portions 4b, and the two end portions 4c was analyzed by energy dispersive X-ray fluorescence analysis. The obtained analytical values are shown in Table 1. According to Table 1, the Si concentration in the electrical steel sheet of Comparative Example 1 was less than 6.5 mass% in the central portion and greater than 6.5 mass% at the end portions. The difference in Si concentration in the direction perpendicular to the direction in which the electrical steel sheet was transported, i.e., the difference between the maximum and minimum Si concentrations, was 0.36 mass%.

[0081] [Table 1]

[0082] Next, the slit nozzle 2 shown in either of FIGS. 3(a) to 3(c) or 4(a) to 4(b) was set in the steel processing apparatus 1, and the steel was siliconized and diffused under the same manufacturing conditions as Comparative Example 1. The conditions for the angle θ of the slit 3 of each slit nozzle 2 are shown in Table 1. The electrical steel sheets of Examples 1 to 3 were siliconized using the slit nozzle 2 shown in FIGS. 3(a), 3(b), and 3(c), in which the angle θ of the slit 3 varied depending on the axial position of the slit nozzle. The angle θ of the slit 3 was 30 degrees at the end and 10 degrees at the center. The electrical steel sheet of Example 4 was siliconized using the slit nozzle 2 shown in FIG. 4(a), in which the total length of the slits 3 per unit length as viewed in the axial direction of the slit nozzle varied depending on the axial position of the slit nozzle. The electrical steel sheet of Example 5 was siliconized using the slit nozzle 2 shown in FIG. 4(b), in which the width of the slit 3 varied depending on the axial position of the slit nozzle. The analytical values obtained by analyzing the obtained electrical steel sheets of Examples 1 to 5 are shown in Table 1. The distribution of the Si concentration shown in Table 1 in the direction perpendicular to the direction in which the electrical steel sheets were transported is shown in FIG.

[0083] According to Table 1, the electrical steel sheets of Examples 1 to 5, which were siliconized using the slit nozzles 2 of Figures 3(a) to 4(b) according to the present invention, had less variation in Si concentration in the direction perpendicular to the conveying direction of the electrical steel sheet than the electrical steel sheet of Comparative Example 1, with a maximum Si concentration difference of 0.10 mass%. Furthermore, according to Figure 7, the variation in Si concentration in the electrical steel sheets according to the present invention in the direction perpendicular to the conveying direction of the electrical steel sheet was controlled within the range of 6.5±0.1 mass%.

[0084] <Example 2>

[0085] As a steel material, an electrical steel sheet was prepared, which was made of steel type B containing 3.3 mass% Si and having other components different from steel type A, and had a width of 600 mm and a thickness of 0.10 mm. This was subjected to a siliconizing treatment and a diffusion treatment under the same manufacturing conditions as those for the electrical steel sheet of comparative example 1 in example 1, to produce an electrical steel sheet of comparative example 2. Next, the Si content of the electrical steel sheet of comparative example 2 was analyzed under the same conditions as in example 1. The obtained analytical values are shown in Table 2. According to Table 2, the Si concentration in the electrical steel sheet of comparative example 2 was greater than 6.5 mass% in the center and less than 6.5 mass% at the edges, contrary to the electrical steel sheet of comparative example 1. The difference in Si concentration in the direction perpendicular to the direction in which the electrical steel sheet was transported was 0.30 mass%.

[0086] [Table 2]

[0087] Next, the slit nozzle 2 shown in either of FIGS. 5(a) to 5(c) or 6(a) to 6(b) was set in the steel processing apparatus 1, and the steel was siliconized and diffused under the same manufacturing conditions as those for Comparative Examples 1 and 2. The conditions for the angle θ of the slit 3 of each slit nozzle 2 are shown in Table 2. The electrical steel sheets of Examples 6 to 8 were siliconized using the slit nozzle 2 shown in FIGS. 5(a), 5(b), and 5(c), in which the angle θ of the slit 3 varied depending on the axial position of the slit nozzle. The angle θ of the slit 3 was 10 degrees at the end and 30 degrees at the center. The electrical steel sheet of Example 9 was siliconized using the slit nozzle 2 shown in FIG. 6(a), in which the total length of the slits 3 per unit length as viewed in the axial direction of the slit nozzle varied depending on the axial position of the slit nozzle. The electrical steel sheet of Example 10 was siliconized using the slit nozzle 2 shown in FIG. 6(b), in which the width of the slit 3 varied depending on the axial position of the slit nozzle. The analytical values obtained by analyzing the obtained electrical steel sheets of Examples 6 to 10 are shown in Table 2. The distribution of the Si concentration shown in Table 2 in the direction perpendicular to the direction in which the electrical steel sheets were transported is shown in FIG.

[0088] According to Table 2, the electrical steel sheets of Examples 6 to 10, which were siliconized using the slit nozzles 2 of Figures 5(a) to 6(b) according to the present invention, had less variation in Si concentration in the direction perpendicular to the conveying direction of the electrical steel sheet than the electrical steel sheet of Comparative Example 2, with a maximum Si concentration difference of 0.12 mass%. Furthermore, according to Figure 8, the variation in Si concentration in the electrical steel sheets according to the present invention in the direction perpendicular to the conveying direction of the electrical steel sheet was controlled within the range of 6.5±0.1 mass%.

[0089] It can be seen from Examples 1 and 2 that electrical steel sheets obtained using the steel processing apparatus according to the present invention or by carrying out the steel manufacturing method according to the present invention have less variation in Si concentration than electrical steel sheets according to the prior art. According to the present invention, it is possible to control the variation in Si concentration in the direction perpendicular to the conveying direction of the electrical steel sheet to within the range of 6.5±0.1 mass%, which was not achievable with the prior art. [Explanation of symbols]

[0090] 1 Steel processing equipment 2 slit nozzles 3 Slit (invention example) 3´ slit (conventional technology) 4 Steel material 4a central part 4b Quarter 4c end θ angle

Claims

1. A steel material treatment facility that modifies steel material by supplying a raw material gas to a surface of the steel material, a conveying means for conveying the steel material; one or more slit nozzles that spray the raw material gas toward the surface of the steel material transported by the transport means, The slit nozzle is provided so that its axial direction is parallel to the surface of the steel material and perpendicular to the direction in which the steel material is conveyed, The shape of the slit of the slit nozzle varies depending on the position in the axial direction of the slit nozzle. Steel processing equipment.

2. In a cross section perpendicular to the axial direction of the slit nozzle, an angle formed by a perpendicular line drawn from the center of the slit nozzle to the surface of the steel material and a line segment connecting the center of the slit nozzle and the center of the slit varies depending on the position in the axial direction of the slit nozzle. The steel processing facility according to claim 1.

3. an opening area of the slit per unit length as viewed in the axial direction of the slit nozzle varies depending on a position in the axial direction of the slit nozzle; The steel material processing facility according to claim 1 or 2.

4. the total length of the slits per unit length as viewed in the axial direction of the slit nozzle varies depending on the position in the axial direction of the slit nozzle; The steel processing facility according to claim 3.

5. The width of the slit varies depending on the position in the axial direction of the slit nozzle. The steel processing facility according to claim 3.

6. Further provided is a heating means for heating the steel material transported by the transport means. The steel material processing facility according to claim 1 or 2.

7. The modification is siliconizing treatment. The steel material processing facility according to claim 1 or 2.

8. The steel material processing equipment according to claim 1 or 2 is provided. Steel manufacturing equipment.

9. A method for treating steel material, which modifies the steel material by supplying a raw material gas to a surface of the steel material, a step of spraying the raw material gas toward a surface of the steel material being transported using one or more slit nozzles, The slit nozzle is provided so that its axial direction is parallel to the surface of the steel material and perpendicular to the direction in which the steel material is conveyed, The shape of the slit of the slit nozzle varies depending on the position in the axial direction of the slit nozzle. How steel is processed.

10. A step of heating the steel material before and / or after the step of blowing the raw material gas is provided. The method for treating steel materials according to claim 9.

11. The modification is siliconizing treatment. The method for treating steel materials according to claim 9.

12. The steel material is modified using the steel material treatment method according to any one of claims 9 to 11. Steel manufacturing method.

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