JP2011510166A - Oriented electrical steel sheet with excellent magnetic properties and method for producing the same - Google Patents

Abstract

A grain-oriented electrical steel sheet having excellent magnetic properties and a method for producing the same are provided. In more detail, the grain-oriented electrical steel sheet and the manufacturing method thereof, which have improved magnetic properties to an extent that could not be expected with conventional similar component systems by adjusting the components and improving the manufacturing method. I will provide a. This grain-oriented electrical steel sheet contains Sn: 0.03-0.07 wt%, Sb: 0.01-0.05 wt%, and P: 0.01-0.05 wt% as essential components.

Description

  The present invention relates to a grain-oriented electrical steel sheet having excellent magnetic properties and a method for producing the same, and more specifically, by adjusting the components and improving the production method, it has not been possible to expect with a similar component system in the past. The present invention relates to a grain-oriented electrical steel sheet and a method for producing the grain-oriented electrical steel sheet that have dramatically improved magnetic properties.

  The electric steel sheet means a silicon steel sheet used as a material for an electric machine or an electric appliance, and is roughly classified into a directional electric steel sheet and a non-oriented electric steel sheet. Among them, the grain-oriented electrical steel sheet is so-called that the orientation of the crystal plane is the {110} plane and the crystal orientation in the rolling direction is parallel to the <001> axis as discovered and proposed by Goss. Consists of crystal grains with Goth collective organization. Such a steel plate is excellent in magnetic properties in the rolling direction.

  Referring to FIG. 1 (reference document: Arai ken et al., “Recent Development of Electrical Steel Sheets”, Japan Iron and Steel Institute, 1995, pp15), the effect of crystal orientation of grain-oriented electrical steel sheets on magnetic properties of grain-oriented electrical steel sheets Is schematically described. FIG. 1 shows the results of testing using a single crystal in order to identify the relationship between the degree to which the actual crystal orientation of the steel sheet deviates from the Goss orientation and the iron loss. As can be seen from the graph in FIG. 1, the lowest iron loss is represented when the angle deviates by about 2 degrees from the Goss direction (meaning the absolute value of the so-called β angle. The β angle will be described later). Therefore, normally, when manufacturing a grain-oriented electrical steel sheet, it manufactures so that a crystal orientation may remove | deviate from a goth orientation because an angle is as close to 2 degree | times as possible. However, the orientation of the electrical steel sheet, which is a polycrystalline material, calculates the area weighted average for the absolute value of the degree (β angle) that the orientation of each crystal grain deviates from the Goss orientation, considering the crystal grain area It can be obtained by doing. Hereinafter, for convenience of description, the above-mentioned “area weighted average obtained with respect to the absolute value of the β angle in the extent that the orientation of each particle deviates from the Goss orientation” is simply “excluded from the Goss orientation” Is displayed.

  As shown in FIG. 2, the degree of deviation from the Goss direction is expressed as α, β, and γ angles. Normally, adjusting the β angle is effective in controlling the magnetic properties of the electrical steel sheet. Are known. Therefore, in this specification, the degree of deviation from the Goth direction with respect to the β angle is simply displayed as “degree of deviation from the Goth direction” as described above.

  In order to manufacture a steel plate so that the orientation of the steel plate is close to the Goth orientation, the orientation of all crystals needs to coincide with the Goth orientation. However, an electrical steel sheet produced by rolling a slab inevitably has a polycrystalline structure, and as a result, the crystal orientation differs from crystal to crystal, so this is matched to be close to the Goth orientation. To do this, special work is required.

  That is, a rolled steel sheet having a polycrystalline structure may contain crystals close to the Goth orientation, but most contain crystals having an orientation greatly deviating from the Goth orientation, so these are used as they are. In this case, it becomes difficult to obtain an electric steel sheet having excellent magnetic properties. Therefore, it is necessary to recrystallize the steel sheet having the polycrystalline structure so that only crystals close to the Goth orientation exist. The crystal orientation that preferentially grows during the recrystallization is determined by the recrystallization temperature. When the recrystallization temperature is well controlled, crystals close to the Goth orientation can preferentially grow. . As a result, the fraction of crystals close to the Goth orientation is small before recrystallization, but after recrystallization, the fraction of crystals near the Goth orientation occupies the majority. Such recrystallization is referred to as secondary recrystallization in order to distinguish it from primary recrystallization (described later).

  At this time, before the secondary recrystallization, primary recrystallization is performed so that the crystals are uniformly distributed. The primary recrystallization is usually performed immediately after the decarburization annealing performed after the cold rolling or simultaneously with the decarburization annealing, and uniform and appropriate crystal grains are formed by the primary recrystallization. It becomes like this. Of course, the orientation of the crystal grains is uniformly distributed, and the fraction of crystal grains having the Goth orientation that is finally obtained by the grain-oriented electrical steel sheet is very low.

  As described above, the primary recrystallized steel sheet is manufactured into a steel sheet having goth orientation with excellent magnetic properties by being secondarily recrystallized at a temperature suitable for providing the goth orientation thereafter. Can. However, when the sizes of crystal grains having different orientations among the primary recrystallized steel plates are different, even if secondary recrystallization occurs at a temperature suitable for providing the Goss orientation, a so-called size effect is achieved. In other words, the larger crystal grains have a more stable effect than the smaller ones, and there is a high possibility that the large grains will grow dominant regardless of the orientation. As a result, the fraction of grains outside the goth orientation is high. Become.

  Therefore, the crystal grains must be distributed in a uniform and appropriate size during the primary recrystallization. When the size of the crystal grains is very fine, the interface energy increases due to the increase of the crystal interface area, and the crystal grains may become unstable. In such a case, secondary recrystallization occurs at a temperature that is too low, and a large amount of crystal grains having no Goth orientation are generated. The appropriate size of such crystal grains varies depending on the type of element (inhibitor) added (described later).

  Further, when the primary recrystallized crystal grains are recrystallized at an appropriate temperature, a large amount of crystal grains having Goth orientation suitable for the grain-oriented electrical steel sheet are formed. Therefore, although it is necessary to raise the temperature of the crystal grains to the appropriate temperature, the temperature inevitably goes through a low temperature range until the temperature is raised to the appropriate temperature. If recrystallization occurs in such a low temperature range, the Goth orientation is dominant and a large amount of crystal grains cannot be obtained. Therefore, a means for suppressing the growth of crystal grains is required so that recrystallization does not occur until the temperature is raised to an appropriate temperature. The means for performing such a role inside the steel sheet can be obtained by segregation or precipitation of the added component, and the element having such a role is called an inhibitor.

  Until the temperature of the crystal is raised to an appropriate secondary recrystallization temperature, the inhibitor is present in the vicinity of the grain boundary in the form of precipitates or segregation, thereby preventing further growth of the crystal grains. When the temperature is raised to an appropriate temperature (secondary recrystallization temperature), the inhibitor functions to promote free growth of crystal grains by being dissolved or decomposed.

  Examples of widely used inhibitors as described above include elements such as MnS and MnSe.

  As an example thereof, Japanese Patent Application Laid-Open No. 51-13469 (Patent Document 1) can be cited. However, the above document discloses a method for producing an electrical steel sheet, in which the directional electrical steel sheet is heated with slab, It is manufactured through the processes of hot rolling, hot rolled sheet annealing, primary cold rolling, intermediate annealing, secondary cold rolling, decarburization annealing, and final annealing, and MnSe and Sb are used as inhibitors. Japanese Laid-Open Patent Publication No. 30-3651 (Patent Document 2) discloses a technology for producing grain-oriented electrical steel sheets, and includes two cold rolling operations including intermediate annealing using MnS as an inhibitor. Provide electrical steel sheet at As another example of using an MnS-based inhibitor, Japanese Patent Application Laid-Open No. 40-15644 (Patent Document 3) can be cited. In this method, MnS and AlN are used as inhibitors, and 80% A product having a high magnetic flux density is obtained by performing the cold rolling once at the above high rolling rate.

  However, the method using MnS as an inhibitor as described above has a problem that the slab must be reheated to a very high temperature in order to form MnS. That is, since MnS present in the slab often exists as coarse precipitates, it may not be able to serve as an inhibitor used in the manufacture of grain-oriented electrical steel sheets. Therefore, after MnS is dissolved, it is necessary to distribute it uniformly. To this end, the slab must be heated to a temperature at which MnS can be dissolved. However, even when considering the thermodynamic equilibrium state, the solid solution temperature of MnS is a very high temperature of about 1300 ° C. or higher, and is sufficiently fast so that it can actually be used in various industrial applications. In order to dissolve MnS at a rate, it is necessary to reheat to about 1400 ° C., which is a much higher temperature.

  When heating a slab at a high temperature as described above, the energy consumed for heating the slab becomes intense, causing the problem that the surface of the slab is melted. However, the life of the heating furnace may be shortened.

  Therefore, it is necessary to introduce an inhibitor capable of reducing the reheating temperature of the slab. An inhibitor provided in accordance with such a requirement is a nitride-based inhibitor. The advantages of the nitride-based inhibitor are as follows. By placing the steel sheet in a nitrogen atmosphere simultaneously with the decarburization annealing or immediately after the decarburization annealing, it is possible to form a condition in which nitrogen easily penetrates into the steel sheet and to permeate nitrogen. The infiltrated nitrogen reacts with a nitride-forming element in the steel sheet to form a nitride, and the nitride serves as an inhibitor. Examples of the nitride include elements such as AlN and (Al, Si) N.

  Since the cold-rolled sheet may be nitrided at an appropriate temperature simultaneously with the decarburization annealing of the cold-rolled sheet, the reheating temperature of the cold-rolled sheet should be similar to the reheating temperature during normal hot rolling. Good. In the field of production of grain-oriented electrical steel sheets, such a reheating pattern is called “low temperature reheating”.

  As an example of the method for producing the grain-oriented electrical steel sheet by the low temperature reheating described above, Japanese Patent Laid-Open No. 1-230721 (Patent Document 4), Japanese Patent Laid-Open No. 1-283324 (Patent Document 5), South Korea There are listed Japanese Patent No. 97-48184 (Patent Document 6) and Korean Patent No. 97-28305 (Patent Document 7). In these methods, ammonia gas is used to form a nitrogen atmosphere. Is used. Since the ammonia gas usually has a property of being decomposed into hydrogen and nitrogen at a temperature of about 500 ° C. or higher, nitrogen is supplied to the steel sheet using the property of ammonia.

  However, the low-temperature reheating method using the nitriding method as described above has a disadvantage in that there is a limit in improving the magnetic characteristics with nitrogen alone.

  As a method for further improving the magnetic properties of grain-oriented electrical steel sheets, other elements that act as inhibitors are added to further increase the fraction of grains that grow in the Goth orientation during secondary recrystallization. There is a means to make it. There is also a means for increasing the fraction of crystals having goth orientation during primary recrystallization and increasing the fraction of crystal grains having goth orientation during secondary recrystallization. Further, the size of the primary recrystallized crystal grains is uniformly distributed in order to prevent larger growth of the crystal grains that could not have the Goth orientation due to the size effect during the secondary recrystallization. There are means.

  As a conventionally proposed method, a method for improving the components of a steel sheet can be mentioned. That is, when elements such as Sn, Sb, and P are added to the electrical steel sheet, the magnetic properties of the electrical steel sheet can be greatly improved for the following reason.

  That is, Sb and Sn not only have the effect of increasing the fraction of crystal grains having the {110} <001> orientation in the primary recrystallization group organization, but also precipitate the sulfides uniformly. effective. Moreover, when the addition amount of Sb and Sn exceeds a fixed level, the effect that the oxidation reaction at the time of decarburization annealing is suppressed can be acquired. Therefore, the temperature at the time of decarburization annealing can be raised, and as a result, primary film formation of a grain-oriented electrical steel sheet can be made easier. In addition, since these elements are precipitated at the grain boundaries and can suppress the growth of the crystal grains, the particle diameter of the secondary recrystallized grains can be reduced. Therefore, the effect of refining the magnetic domain by forming the recrystallized secondary recrystallized grains can be obtained.

  Further, P is known to have an effect of improving the collective organization at the time of primary recrystallization. That is, it has a function of increasing the fraction of crystal grains having Goth orientation during primary recrystallization.

  Adding elements such as Sn, Sb, and P to grain-oriented electrical steel sheets is disclosed in Japanese Patent Laid-Open No. 2-294428 (Patent Document 8), Japanese Patent Laid-Open No. 2006-241503 (Patent Document 9), Japan. Japanese Unexamined Patent Application Publication No. 2007-254829 (Patent Document 10), Japanese Unexamined Patent Application Publication No. 2007-051338 (Patent Document 11), and Japanese Unexamined Patent Application Publication No. 11-335794 (Patent Document 12).

  Among these, the Japanese Patent Laid-Open No. 2-294428 discloses a grain-oriented electrical steel sheet having a high magnetic flux density obtained by adding P: 0.0007 to 0.045 wt% to the grain-oriented electrical steel sheet. In addition, the above Japanese Unexamined Patent Publication No. 2006-241503 contains P: 0.015 to 0.07% by weight together with other components, and Sb: 0.005 to 0.2% by weight as necessary. And Sn: A method for producing a silicon steel sheet having stable magnetic properties by further adding one or two selected from 0.01 to 0.5% by weight.

  In the above Japanese Unexamined Patent Application Publication No. 2007-254829, there is a method for producing a grain-oriented electrical steel sheet having excellent magnetic properties including 0.02 to 0.30% by weight of one or more of Sn, Sb and P as required. In addition, P: 0.2 wt% or less is added to the above Japanese Unexamined Patent Publication No. 2007-051338, and Sb: 0.001 to 0.02 and Sn: 0 as necessary. A method for producing a grain-oriented electrical steel sheet excellent in magnetic properties in the 45 ° direction, which further contains one or more elements selected from 0.002 to 0.1% by weight is disclosed.

  In addition, in the above Japanese Patent Laid-Open No. 11-335794, one or more elements selected from the elements consisting of Sn, Sb, P, B, Bi, Mo, Te and Ge in the component system of the electric steel sheet are disclosed. Discloses a method for producing an electric steel sheet to which 0.0005 to 2.0% by weight is added.

  As described above, the above patent document discloses a configuration in which elements such as Sn, Sb, and P are added. However, these ranges are described extensively, and one or more of these elements are included. It is described only to the extent that it is included. That is, according to the research results up to now, only the extent that the magnetic properties of the electrical steel sheet can be improved by the addition of Sn, Sb and P is disclosed, and the appropriate content of each element and the content of these elements are disclosed. Since there is no disclosure of a synergistic effect due to the interaction, provision of specific means for improving the magnetic properties of the electrical steel sheet through appropriate addition of the above elements is still insufficient.

  And, the electrical steel sheet containing Sn, Sb and P has different behaviors of primary recrystallization and secondary recrystallization as compared with the electrical steel sheet containing only the conventional inhibitor. The prior art does not provide a solution to this. That is, when such elements are added, the size of the primary recrystallized grains is reduced compared to the steel material to which these elements are not added, and the suppressing power against secondary recrystallization is increased. The control method of the annealing work paying attention to is not disclosed in the prior art.

  In addition to the above items, secondary recrystallization is performed during a series of processes of the method of manufacturing an electrical steel sheet, such as hot rolling of a slab, hot-rolled sheet annealing, cold rolling, decarburization annealing, and final annealing. However, although it occurs in the final annealing step, there is a problem that the initial temperature rise and maintenance time for the secondary recrystallization is excessive and productivity is lowered.

  That is, since the final annealing is performed by heating the coiled steel plate at a high temperature, there is a risk that the steel plate and the steel plate adhere to each other, and the annealing is mainly performed on the coiled steel plate surface before the final annealing. Although the separation system is applied, since the surface of each coiled steel plate is coated with MgO in a paste form together with moisture, each coiled steel plate is subjected to a two-step soaking process. The two-stage soaking process includes a primary soaking process for removing moisture from the paste, and a heating process for heating the steel plate to the secondary recrystallization temperature after the primary soaking process. And a secondary soaking process for maintaining the steel sheet.

In the primary soaking process, moisture coexisting with MgO is removed, and the Si component in the steel sheet contributes to the reaction, so that a composite oxide film of MgO and SiO ₂ is formed on the steel sheet surface.

  As described above, since the orientation of preferentially growing crystal grains differs depending on the secondary recrystallization temperature, the secondary recrystallization temperature must be precisely controlled. In other words, if the inhibitor such as MnS or AlN is re-dissolved in the steel sheet, secondary recrystallization occurs, and thus the inhibitor is abruptly removed within a temperature range limited as much as possible. Most preferred. However, when the temperature rise is rapid, the inhibitor may be removed in a wide temperature range, so that crystal grains with various orientations grow together, and crystal grains close to the Goss orientation predominate. It becomes difficult to obtain a grain-oriented electrical steel sheet having a large number and excellent magnetic properties. Therefore, conventionally, the steel sheet is heated very slowly to the secondary recrystallization temperature, particularly at a temperature rising rate of 10 to 17 ° C. At such a slow temperature increase rate, the time required for the temperature increase to the secondary soaking temperature is consumed excessively, causing a decrease in productivity.

  In addition, AlN and MnS, which have been used so far, are useful for increasing the fraction of crystal grains having goth orientation during secondary recrystallization, and contribute to the magnetic properties of the final grain-oriented electrical steel sheet. Is rather harmful and is preferably removed after secondary recrystallization has occurred. When the electric steel sheet is maintained at a high temperature in which the atmosphere is controlled, these components can be removed, so that the secondary soaking is performed at a high temperature. In the second-order soaking, not only the N and S components are reduced, but also the island-like crystal grains are reduced. Therefore, the above process is a very useful process. However, in most electrical steel sheets, in order to form a large amount of inhibitors such as AlN and MnS, a large amount of N and S are dissolved in the steel, and then primary and secondary recrystallization operations are performed. For this reason, the secondary soaking time required for the removal of the large amount of N and S is excessive, leading to a decrease in productivity.

Japanese Unexamined Patent Publication No. 51-13469 Japanese Unexamined Patent Publication No. 30-3651 Japanese Unexamined Patent Publication No. 40-15644 Japanese Patent Laid-Open No. 1-2230721 Japanese Unexamined Patent Publication No. 1-283324 Korean Published Patent No. 97-48184 Korean Published Patent No. 97-28305 Japanese Laid-Open Patent Publication No. 2-294428 Japanese Unexamined Patent Publication No. 2006-241503 Japanese Unexamined Patent Publication No. 2007-254829 Japanese Unexamined Patent Publication No. 2007-051338 Japanese Unexamined Patent Publication No. 11-335794

  The present invention has been made to solve the above-described problems of the prior art, and according to one aspect of the present invention, the contents of Sn, Sb, and P are controlled within an appropriate range, so A grain-oriented electrical steel sheet with improved magnetic properties is provided by optimizing the mutual relationship and adding an additional magnetic property improving element.

  According to another aspect of the present invention, there is provided a method for producing a grain-oriented electrical steel sheet that solves the problem of productivity reduction that is likely to occur when an electrical steel sheet having excellent characteristics according to the present invention is produced.

  According to still another aspect of the present invention, a method for producing a grain-oriented electrical steel sheet having a heating pattern suitable for the above-described component system is provided.

  According to one aspect of the present invention, the direction includes Sn: 0.03-0.07 wt%, Sb: 0.01-0.05 wt% and P: 0.01-0.05 wt% as essential components An electrical steel sheet is provided.

  At this time, P + 0.5Sb may be in the range of 0.0370 to 0.0630 (where P and S mean the content (% by weight) of the corresponding element).

  And: As: 1.40% by weight or less, Cu: 0.50% by weight or less, Bi: 0.1% by weight or less, Te: 1.40% by weight or less, Ni: 1.40% by weight or less, Cr: 0 .35% by weight or less, Pb: 1.40% by weight or less, and at least one selected from the group consisting of Mo, B, Ge, Nb, Ti and Zn: a total of 1.40% by weight or less 1 type or 2 or more types can further be included.

  The grain-oriented electrical steel sheet further includes Si: 2.0 to 4.0% by weight, acid-soluble Al: 0.020 to 0.040% by weight, and Mn: 0.01 to 0.20% by weight. Can do.

  The degree of the crystal orientation of the electrical steel sheet deviating from the Goth orientation may be less than 3 degrees.

  Moreover, the grain-oriented steel sheet can be manufactured from a steel slab further including C: 0.04 to 0.07 wt%, N: 10 to 55 ppm, and S: 0.0010 to 0.0055 wt%.

  Moreover, hot rolling and annealing a steel slab containing Sn: 0.03-0.07% by weight, Sb: 0.01-0.05% by weight and P: 0.01-0.05% by weight as essential components And a step of cold rolling to produce a steel plate; a step of decarburizing annealing and nitriding annealing of the cold rolled steel plate in a temperature range of 800 to 950 ° C .; and a step of final annealing the annealed steel plate; In the case where the final annealing stage includes a primary soaking stage, a temperature raising stage, and a secondary soaking stage, the temperature raising temperature is initially raised at a temperature raising rate of 18 to 75 ° C./hr. Then, the manufacturing method of an electrical steel sheet which heats up in the range of 10-15 degree-C / hr within the range of 900-1020 degreeC is provided.

  At this time, P + 0.5Sb may be in the range of 0.0370 to 0.0630 (where P and S mean the content (% by weight) of the corresponding element).

  And said steel slab is As: 1.40 weight% or less, Cu: 0.50 weight% or less, Bi: 0.1 weight% or less, Te: 1.40 weight% or less, Ni: 1.40 weight% Hereinafter, at least one selected from the group consisting of Cr: 0.35 wt% or less, Pb: 1.40 wt% or less, and Mo, B, Ge, Nb, Ti, and Zn: 1.40 in total One or more of the weight percents or less may be further included.

  And the said steel slab is Si: 2.0-4.0 weight%, acid-soluble Al: 0.020-0.040 weight%, Mn: 0.01-0.20 weight%, C: 0.04 -0.07 wt%, N: 10-55 ppm and S: 0.0010-0.0055 wt%.

  And the step of reheating the steel slab can include controlling the heating temperature so that the content of N to be re-dissolved is in the range of 10 to 40 ppm.

  In addition, the heating temperature of the steel slab may be in the range of 1050 to 1250 ° C.

  Further, the secondary soaking temperature may be in the range of 1150 to 1250 ° C.

  According to the present invention, it is possible to produce a grain-oriented electrical steel sheet with improved magnetic properties by optimizing the content of added component elements and making maximum use of the synergistic effect between the elements, The problem of the productivity fall which is easy to generate | occur | produce when manufacturing the said grain-oriented electrical steel sheet can be solved.

It is the graph which showed the phenomenon in which an iron loss changes with the grade (beta angle of FIG. 2) from which the crystal orientation of the steel plate deviated from the Goss orientation. It is a conceptual diagram for conceptually explaining the degree of deviation from the Goss orientation indicated by alpha (α), beta (β), and gamma (γ) angles. It is the graph which showed that the phenomenon by which an iron loss is improved by adding Sn, Sb, and P component within a fixed content range exceeds the conventionally estimated grade. It is the graph which showed the phenomenon in which an iron loss is improved when Sn content is increased, fixing the content of Sb and P. 6 is a graph showing a phenomenon in which iron loss is improved when the Sb content is increased while the Sn and P contents are fixed. 6 is a graph showing a phenomenon in which iron loss is improved when the P content is increased while the Sn and Sb contents are fixed. It is the graph which showed the phenomenon in which an iron loss is improved when P and Sb are increased, with Sn content fixed. It is the graph which expressed the phenomenon of FIG. 7 using the numerical formula of P + 0.5Sb.

  Hereinafter, exemplary embodiments of the present invention will be described in detail.

  The inventors of the present invention are able to reduce the amount of Sn, Sb and P in the component system of conventional electrical steel sheets to which Sn, Sb and P are added, and the effect of improving the magnetic properties generated when these elements are controlled together. As a result of deep and extensive research, when the addition range of the Sn, Sb, and P components is further controlled by appropriately controlling the element content range and the relationship between the elements, the criticality remarkably superior to the conventionally expected effect. It was discovered that it can have an effect, and the present invention has been reached.

  FIG. 3 shows the concept of the present invention. FIG. 3 is a graph conceptually showing that the iron loss of the electrical steel sheet changes with respect to the Sn, Sb or P content. In the drawing, the horizontal axis indicates the content of Sn, Sb or P, and the vertical axis indicates the iron loss.

  As shown in FIG. 3, according to the Sn, Sb or P content range set in the conventional content range, it is known that the change in iron loss represents a form of a continuous line having a minimum point within the appropriate range. However, in one embodiment of the present invention, it has been discovered that iron loss can be dramatically reduced when having certain conditions within the conventional content range described above. That is, referring to FIG. 3, within the Sn, Sb or P content within the conventional content range, it should be expected that the change in iron loss represents a continuous line without a large difference in iron loss. According to their experimental results, when the above components are within a certain content range, the effect is remarkably improved to the extent that it could not be predicted conventionally.

  Further, the effect of improving the iron loss is not obtained by controlling only the content of the corresponding element within the specific component range, and cannot be obtained unless these three elements are added simultaneously. That is, for example, even if the content of Sb is simply changed within the range presented in the prior art, the same remarkable effect as that shown in FIG. A significant effect can be obtained only when it exists in Therefore, they must be added at the same time, and unless the appropriate ranges are controlled simultaneously, the critical effect pursued by the present invention cannot be obtained. As an experimental result to support this, it was observed that when only Sb and P were added without adding Sn, locally small crystal grains were observed. It is determined that it is a trace of crystal grains in other orientations instead of orientations, and as a result, there is a risk of deteriorating the magnetic properties of the electrical steel sheet. However, when Sn, Sb and P are added at the same time, uniform secondary recrystallized grains are obtained, and the aggregate organization (RD // [001]) grows strongly in the primary recrystallized steel sheet. I was able to confirm.

  In addition, when P and Sb are controlled together, the content of P and Sb needs to be controlled by a single mathematical formula because other critical synergistic effects can be induced. .

  As a result, in the present invention, among the components of the electrical steel sheet, the contents of Sn, Sb and P are controlled as follows, and the content relation of P and Sb expressed by the following formula is controlled within an appropriate range. It is characterized by doing.

1) Sn: 0.03 to 0.07% by weight
2) Sb: 0.01 to 0.05% by weight
3) P: 0.01 to 0.05% by weight
4) P + 0.5Sb: 0.0370 to 0.0630 (where P and S mean the content (% by weight) of each element)

  Hereinafter, the reason for determining the content of each element will be described.

Sn: 0.03-0.07% by weight
Sn serves to increase the number of secondary nuclei in the {110} <001> orientation and reduce the size of secondary crystal grains. As a result, the addition of Sn can improve iron loss. Sn also plays an important role in suppressing grain growth through segregation at the grain boundaries, and this reduces the effect of suppressing grain growth as the AlN grains become coarser and the Si content increases. To compensate. Therefore, as a result, it is possible to ensure the successful formation of the secondary recrystallized aggregate composition in the {110} <001> orientation while having a relatively high Si content. That is, it is possible not only to increase the Si content but also to decrease the final thickness without decreasing the completeness of the secondary recrystallization texture in the {110} <001> orientation. As described above, the Sn content is preferably 0.03 to 0.07% by weight within a range in which the content of other components is appropriately adjusted. That is, as described above, when the Sn content range is controlled to 0.03 to 0.07% by weight, it is possible to confirm a discontinuous and significant iron loss reduction effect that could not be predicted in the past. Thus, the Sn content range is preferably controlled within the above range. Moreover, since there exists a problem that brittleness will increase when there is too much Sn content, when controlling Sn in the range mentioned above, brittleness can be reduced.

Sb: 0.01 to 0.05% by weight
Sb has an effect of segregating at the grain boundaries and suppressing excessive growth of primary recrystallized grains. By adding Sb and suppressing grain growth in the primary recrystallization stage, non-uniformity in the size of the primary recrystallized grains in the thickness direction of the steel sheet is removed, and at the same time, the secondary recrystallized grains are stabilized. By making it form, the grain-oriented electrical steel sheet which was excellent in the magnetic characteristic can be manufactured. In particular, the effect of Sb can be greatly improved as Sb was 0.01 to 0.05% by weight, which could not be predicted in the past. As described above, Sb segregates at the grain boundaries and suppresses excessive growth of the primary recrystallized grains. However, if Sb is 0.01% by weight or less, its function is properly exhibited. If Sb is contained in an amount of 0.05% by weight or more, the size of the primary recrystallized grains becomes too small and the secondary recrystallization start temperature is lowered to deteriorate the magnetic properties or the grain growth. This is because there is a possibility that the secondary recrystallized grains may not be formed due to an excessively large suppression force against.

P: 0.01 to 0.05% by weight
P promotes the growth of primary recrystallized grains in a directional electrical steel sheet using a low temperature heating method, increases the secondary recrystallization temperature, and increases the degree of integration of {110} <001> orientations in the final product. When the primary recrystallized grains are too large, the secondary recrystallization becomes unstable, but as long as secondary recrystallization occurs, the primary recrystallized grains are large in order to increase the secondary recrystallization temperature. Is more advantageous. On the other hand, P is a primary recrystallized steel sheet that not only increases the number of crystal grains having {110} <001> orientation, thereby reducing the iron loss of the final product, but also the primary recrystallized steel sheet. Thus, the {111} <112> collective organization is strongly grown to increase the degree of accumulation of crystal grains in the {110} <001> orientation of the final product, so that the magnetic flux density is also increased. P also segregates at the crystal grain boundary at a high temperature of about 1000 ° C. during secondary recrystallization annealing, and has an action of reinforcing the inhibitory force by delaying the decomposition of the precipitate. When the P content is limited to 0.01 to 0.05% by weight, a remarkable effect that cannot be predicted in the past can be obtained by improving the iron loss. In order to fully exhibit the effect of P, the content of P needs to be 0.01% by weight or more. When P is 0.05% by weight or more, the size of primary recrystallized grains is rather reduced, and not only secondary recrystallization becomes unstable, but also brittleness is increased and cold rolling properties are hindered. Because.

P + 0.5Sb: 0.0370 to 0.0630 (P and S mean the content (% by weight) of each element)
According to the experimental results of the inventors of the present invention, in addition to the case where each element is added, when the content of P + 0.5Sb is controlled within the above-described range, a further excellent iron loss improvement effect is obtained. The reason is that some of the above elements are added together to obtain a synergistic effect, and when the synergistic effect satisfies the above formula range, it is discontinuously maximized compared to other numerical ranges. It is judged that there is. Therefore, in addition to controlling the content range of each element, it is more preferable to control the P + 0.5Sb to the above-described range.

  When the components of the electric steel sheet are limited to the above-described content range, the magnetic characteristics can be greatly improved because the orientation of the steel sheet is formed close to the Goth direction. Therefore, the electrical steel sheet of the present invention having advantageous effects includes Sn: 0.03 to 0.07% by weight, Sb: 0.01 to 0.05% by weight, and P: 0.01 to 0.05% by weight. It is an electrical steel sheet included as an essential component. In addition to limiting the components to the above range, P + 0.5Sb should be limited to a range of 0.0370 to 0.0630 (where P and S mean the content (% by weight) of each element). Is more preferable.

  In addition to limiting the components such as Sn, Sb and P as described above, As, Cu, Bi, Te, Ni, Cr, Pb, Mo, B, Ge, Nb, Ti and Zn as described below When adding one or two or more elements selected from the group consisting of a proper content, it is advantageous to control the secondary recrystallization temperature and to make the crystal grain size uniform. The magnetic characteristics can be further improved by such effects. Hereinafter, the reason for adding each component will be described in more detail.

As: 1.40% by weight or less According to the research results of the present inventors, As is an element for assisting the function of the inhibitor such as P, Sb and Sn to further improve the magnetic properties. When the element is added, the secondary recrystallization start temperature is increased, and therefore, the effect of stably performing secondary recrystallization at a temperature advantageous for the growth of crystal grains having goth orientation is obtained. However, if As is added in excess of 1.40% by weight, deterioration of the coating produced during annealing of the steel sheet cannot be avoided and the magnetic properties are also deteriorated, so the upper limit of the As content is 1.40. Limited to weight percent. Further, even if the content of As is insufficient, the magnetic properties are not deteriorated as compared with the case where As is not added at all. However, since it is difficult to obtain the advantageous effect due to the addition, in order to obtain the advantageous effect, As More preferably, 0.003% by weight or more is added.

Cu: 0.50% by weight or less Cu can precipitate as fine particles in the hot rolling stage and act as an inhibitor against the growth of primary recrystallized grains. In particular, the effect of Cu is larger in the process of performing decarburization simultaneously with nitriding. Simultaneous decarbonization increases the non-uniformity of the primary recrystallized grain size compared to the nitriding step after decarburization, but if the non-uniformity of the primary recrystallized grain size increases, Since the grown crystal grains are secondarily recrystallized due to the size effect, the magnetic properties of the final product may be deteriorated. Such a problem can be prevented by adding an appropriate amount of Cu that forms sulfide. That is, when adding a small amount of Cu, the sulfide can be made fine and the number can be increased. In other words, Cu precipitates finely on the sulfide in the hot rolling stage and suppresses excessive grain growth of the primary recrystallized grains, so that the size of the crystal grains can be made uniform, and consequently Since only Goss crystal grains are selectively caused by secondary recrystallization, it is possible to produce a grain-oriented electrical steel sheet that is superior in magnetic properties. However, if added over 0.50% by weight, the size of the primary recrystallized grains becomes too small and the secondary recrystallization start temperature becomes low, thereby degrading the magnetic properties. The upper limit of the amount added is preferably limited to 0.50% by weight. Further, even if the Cu content is insufficient, the magnetic properties are not deteriorated as compared with the case where Cu is not added at all. However, since it is difficult to obtain the advantageous effect due to the addition of Cu, in order to obtain the advantageous effect described above. It is more preferable to add 0.05% by weight or more of Cu.

Bi: 0.1 wt% or less In the present invention, in addition to the above advantageous composition, Bi is preferably added at 0.1 wt% or less. According to the research results of the inventors, the Bi is added to act as an auxiliary inhibitor to increase the secondary recrystallization start temperature and stably form the secondary recrystallization. In this case, it is possible to produce a grain-oriented electrical steel sheet that is superior in magnetic properties. However, if Bi is added in an amount exceeding 0.1% by weight, deterioration of the coating film produced during the annealing of the steel sheet cannot be avoided, and the magnetic properties are also deteriorated. Limit to 1% by weight. Further, even if the Bi content is insufficient, the magnetic properties are not deteriorated as compared with the case where Bi is not added at all. However, since it is difficult to obtain the advantageous effect due to the addition of Bi, in order to obtain the advantageous effect described above. It is more preferable to add 0.005% by weight or more of Bi.

Te: 1.40% by weight or less According to the research results of the present inventors, Te is an element for assisting the function of the inhibitor such as P, Sb and Sn to further improve the magnetic properties. When the element is added, the secondary recrystallization start temperature is increased, so that the effect of stably performing secondary recrystallization at a temperature advantageous for the formation of crystal grains having goth orientation is obtained. However, if Te is added in excess of 1.40% by weight, deterioration of the coating film produced during annealing of the steel sheet cannot be avoided and the magnetic properties are also deteriorated. Therefore, the upper limit of the Te content is 1. Limit to 40% by weight. Further, even if the Te content is insufficient, the magnetic properties are not deteriorated as compared with the case where Te is not added at all, but it is difficult to obtain the advantageous effect due to the addition of Te. More preferably, 0.01% by weight or more of Te is added.

Ni: 1.40% by weight or less According to the research results of the present inventors, the Ni improves the hot-rolled sheet assembly, acts as an auxiliary inhibitor, increases the secondary recrystallization start temperature, Since secondary recrystallization is stably formed, when Ni is added, a grain-oriented electrical steel sheet having superior magnetic properties can be produced. However, if Ni is added in excess of 1.40% by weight, deterioration of the coating produced during annealing of the steel sheet cannot be avoided and magnetic properties are also deteriorated. Therefore, the upper limit of the Ni content is 1. Limit to 40% by weight. In addition, even if the Ni content is insufficient, the magnetic properties are not deteriorated as compared with the case where Ni is not added at all, but it is difficult to obtain the advantageous effect due to the addition of Ni. More preferably, Ni is added in an amount of 0.01% by weight or more.

Cr: 0.35% by weight or less The above Cr is a ferrite-forming element and has the effect of growing primary recrystallized grains, increasing the number of {110} <001> oriented grains in the primary recrystallized plate. Therefore, if Cr is added, a grain-oriented electrical steel sheet having a low iron loss and a high magnetic flux density can be produced. However, if Cr is added in an amount exceeding 0.35% by weight, it will interfere with nitriding by forming a dense oxide layer on the surface of the steel sheet in the simultaneous decarburization and nitriding annealing process. The upper limit of the amount is limited to 0.35% by weight. In addition, even if the Cr content is insufficient, the magnetic properties are not deteriorated as compared with the case where Cr is not added at all, but it is difficult to obtain the advantageous effect due to the addition of Cr. It is more preferable to add 0.02% by weight or more of Cr.

Pb: 1.40% by weight or less In the present invention, in addition to the above advantageous elements, it is preferable to add Pb at 1.40% by weight or less. According to the research results of the present inventors, the Pb acts as an auxiliary inhibitor to increase the secondary recrystallization start temperature and stably form the secondary recrystallization. Therefore, Pb is added. In this case, it is possible to produce a grain-oriented electrical steel sheet that is superior in magnetic properties. However, if Pb is added in excess of 1.40% by weight, deterioration of the coating film produced during annealing of the steel sheet cannot be avoided, and magnetic properties are also deteriorated. Therefore, the upper limit of the Pb content is 1. Limit to 40% by weight. Further, even if the Pb content is insufficient, the magnetic properties are not deteriorated as compared with the case where Pb is not added at all. However, it is difficult to obtain the advantageous effect due to the addition of Pb. More preferably, 0.005% by weight or more of Pb is added.

At least one or more selected from the group consisting of Mo, B, Ge, Nb, Ti, and Zn: 1.40% by weight or less in total In the present invention, in addition to the above advantageous elements, Mo, B, Ge, Preferably, at least one element selected from the group consisting of Nb, Ti and Zn is added in a total amount of 1.40% by weight or less. According to the research results of the present inventors, these elements are elements for assisting the function of the inhibitor such as P, Sb and Sn to improve the magnetic properties, and these elements are added. In this case, the secondary recrystallization start temperature is increased, and therefore, the effect of stably performing secondary recrystallization at a temperature advantageous for the formation of crystal grains having goth orientation can be obtained. However, if added in excess of 1.40% by weight, deterioration of the coating produced during annealing of the steel sheet cannot be avoided and the magnetic properties are also deteriorated. Therefore, the total amount of these elements added is 1. Limit to 40% by weight. In addition, even if the content of each additive component is insufficient, the magnetic properties are not deteriorated compared to the case where it is not added at all, but it is difficult to obtain the advantageous effect due to the addition, in order to obtain the advantageous effect described above, It is more preferable to add 0.003% by weight or more of these elements in total.

  Therefore, the more preferable composition of the electric steel sheet of the present invention is essential Sn: 0.03-0.07 wt%, Sb: 0.01-0.05 wt% and P: 0.01-0.05 wt%. As components, As: As: 1.40% by weight or less, Cu: 0.50% by weight or less, Bi: 0.1% by weight or less, Te: 1.40% by weight or less, Ni: 1.40% by weight %, Cr: 0.35 wt% or less, Pb: 1.40 wt% or less, and at least one selected from the group consisting of Mo, B, Ge, Nb, Ti and Zn: One or more of 40% by weight or less may be further included. In addition to limiting the content of the above elements to the above range, P + 0.5Sb is set in a range of 0.0370 to 0.0630 (where P and S mean the content (% by weight) of each element). More preferably, it is limited.

  And according to the research results of the present inventors, in order to ensure excellent iron loss, the degree of the crystal orientation of the electrical steel sheet of the present invention containing the above elements deviating from the Goth orientation is less than 3 degrees. More preferably.

  In addition to the elements described above, the electrical steel sheet includes additional elements usually used in the electrical steel sheet, such as Si, Mn, and Al, and other impure components contained unavoidably. The elements can be easily applied to the electrical steel sheet of the present invention by analogizing from the types of components used in ordinary electrical steel sheets and their content ranges, so it is necessary to limit each content range of additional elements. Rather, it is important to limit the contents of Sn, Sb and P, the Sn, Sb and P and their relationship, and additional elements added as necessary to the above-mentioned ranges.

  However, more preferred examples of additional elements such as Si, Mn and Al suitable for the component system of the present invention are provided below and briefly described.

Si: 2.0 to 4.0% by weight
Si is used as a basic element of the electrical steel sheet, and increases the specific resistance of the material to reduce the core loss, that is, the iron loss. When the Si content is less than 2.0%, the specific resistance is reduced and the iron loss characteristics are deteriorated. When the Si content is more than 4.0% by weight, the steel becomes brittle and cold rolling becomes extremely difficult. The formation of secondary recrystallized grains becomes unstable. Therefore, Si is set to 2.0 to 4.0% by weight.

Acid-soluble Al: 0.020-0.040% by weight
Al is a component that finally acts in the form of nitrides such as AlN, (Al, Si) N, (Al, Si, Mn) N and acts as an inhibitor, and its content is less than 0.02%. In this case, a sufficient effect on the inhibitor cannot be expected, and if it is too high, the Al-based nitride precipitates and grows very coarsely, so that the effect as the inhibitor is insufficient. Therefore, the content of Al is set to 0.020 to 0.040% by weight.

Mn: 0.01-0.20% by weight
Manganese (Mn), like Si, has the effect of increasing specific resistance and reducing iron loss, reacting with nitrogen introduced by nitriding with Si, and depositing (Al, Si, Mn) N As a result, the growth of primary recrystallized grains is suppressed and secondary recrystallization occurs. However, when Mn is added in an amount of 0.20% by weight or more, the austenite phase transformation is promoted during hot rolling, so that the size of the primary recrystallized grains is reduced and the secondary recrystallization is made unstable. Therefore, Mn is 0.20% by weight or less. In addition, Mn is an austenite-forming element that increases the austenite fraction during reheating of the hot-rolled sheet to increase the amount of precipitates, and primary recrystallized grains that grow through refinement of precipitates and MnS formation grow too much. It is necessary to contain 0.01% by weight or more because there is an effect of avoiding it. Therefore, Mn is limited to 0.01 wt% or more and 0.2 wt% or less.

  C is removed in the decarburization annealing process after cold rolling, and N and S are preferably removed as much as possible through atmosphere control during the secondary soaking process. Regarded as an impurity. However, since these components exist in the electric steel sheet for various reasons until cold rolling, a steel slab, a hot-rolled steel sheet, and a cold-rolled steel sheet for producing the electric steel sheet (the steel sheet immediately after the cold rolling) ) May be included within a predetermined range, and in the present invention, it is more preferably controlled within the following range.

C: 0.04 to 0.07% by weight
C is a component that is hardly useful for improving the magnetic properties of the grain-oriented electrical steel sheet that is the subject of the present invention, so it is preferably removed as much as possible. However, when C is contained above a certain level, in the rolling process, the austenite phase transformation of the steel is promoted and a hot rolling organization is formed during hot rolling to form a uniform microstructure. Since C is useful, it is preferable that 0.04% by weight or more of C is contained. However, when there is too much content of C, a coarse carbide | carbonized_material will be produced | generated and it will become difficult to remove at the time of decarburization. Therefore, it is preferable that C is initially included in the above range.

N: 10 to 55 ppm
N is an element that reacts with Al or the like to re-fine crystal grains. When these elements are properly distributed, it is useful to ensure a fine structure after cold rolling to ensure an appropriate primary recrystallization grain size. The crystal grains are excessively refined, and as a result, the driving force that causes the crystal grains to grow during the secondary recrystallization is increased, and the crystal grains can be grown to an unfavorable orientation. Moreover, when there is too much N content, it will take much time to remove in the last annealing process. Therefore, the upper limit of the nitrogen content is set to 55 ppm. However, as described later, since the content of nitrogen dissolved at the time of reheating the slab must be 10 ppm or more, the lower limit of the nitrogen content is set in consideration of the ratio of N that can be dissolved again. Set to 10 ppm.

S: 0.0010 to 0.0055%
When S is contained in the slab in excess of 0.0055%, it is re-dissolved and precipitated during heating of the hot-rolled slab, so the size of the primary recrystallized grains is reduced and the secondary recrystallization start temperature is reduced. To lower the magnetic properties of the steel. Moreover, since much time is required to remove S in the solid solution state in the secondary soaking section of the final annealing step, productivity of the grain-oriented electrical steel sheet is lowered. On the other hand, when the S content is as low as less than 0.0055%, there is an effect that the size of the initial crystal grains before cold rolling becomes coarse, so that nuclei are generated in the deformation band in the primary recrystallization step { 110} The number of crystal grains having <001> orientation is increased. Therefore, the size of the secondary recrystallized grains is reduced to improve the magnetic properties of the final product, so S is set to 0.0055% or less. Since S forms MnS and affects the size of the primary recrystallized grains to some extent, S can be contained in an amount of 0.001 wt% or more. Therefore, the range of S is limited to 0.0010 to 0.0055%.

  In addition to the elements described above, various elements included in the grain-oriented electrical steel sheet can be included as alloy elements of the electrical steel sheet of the present invention, as understood by those having ordinary knowledge in the technical field to which the present invention belongs. Would be able to. Naturally known combinations of elements and their application naturally belong to the scope of the present invention.

  The aromatic electrical steel sheet of the present invention can be manufactured by a normal manufacturing method for electrical steel sheets widely known in the art, but it is more preferable to manufacture the aromatic electrical steel sheet through the following manufacturing method. Below, a more preferable manufacturing method is demonstrated in detail. Conditions that are not specifically described below are based on normal conditions.

  Until the process of manufacturing the cold-rolled steel sheet, it may be manufactured by a normal manufacturing method. That is, after the steel slab is hot-rolled, the hot-rolled sheet slab is annealed, and then the annealed steel slab is cold-rolled from one of the methods widely known in the art. It can be selected and can be applied with modifications if necessary. In addition, an additional process required in the hot rolling and cold rolling processes of the electric steel sheet such as pickling can be naturally included and applied.

  However, when the steel slab is reheated for hot rolling, it is preferable to adjust the reheating temperature appropriately so that N and S are incompletely solid solution. In particular, the N content is preferably controlled to be 10 to 40 ppm. That is, according to the research results of the inventors of the present invention, it is not important to control the content of all N within an appropriate range. Since it is important to control the amount, the content of N dissolved again at the time of reheating is controlled so as to fall within an appropriate range. In other words, the degree of crystal grain refinement varies depending on the amount of nitride deposited, but if the crystal grain becomes too fine, it may grow to a crystal grain having an orientation different from the Goth orientation. Conversely, if the crystal grains become too coarse, undesirable crystal grains may not be removed during secondary recrystallization. Therefore, it is preferable to set the content of N to be dissolved in the range of 10 to 40 ppm. The slab reheating temperature for controlling the content of N to be dissolved can be set in consideration of the Al content contained in the steel, but the Al content that can be preferably contained in the present invention. In consideration of the above, the reheating temperature is more preferably 1050 to 1250 ° C.

  Thereafter, the process up to the cold rolling may be appropriately selected and applied from one of the usual methods as described above, and detailed description thereof will be omitted. However, the thickness of the hot-rolled steel sheet for producing the grain-oriented electrical steel sheet is usually 1.8 to 3.5 mm, the thickness of the cold-rolled steel sheet is usually 0.18 to 0.35 mm, For sheet annealing, a method of heating to 1000 to 1200 ° C., soaking at 850 to 950 ° C., and then cooling is used. When going through the above process, the average size of the precipitate after hot rolling or after hot-rolled sheet annealing is 300 to 3000 mm.

  The cold-rolled steel sheet will subsequently undergo decarburization annealing and recrystallization annealing, which will be described in detail.

The cold-rolled steel sheet is decarburized and nitride-annealed in an atmosphere of a mixed gas of ammonia + hydrogen + nitrogen. The above-mentioned decarburization and nitridation annealing methods can easily apply the conventional nitridation annealing method. The nitridation annealing can be performed simultaneously with the decarburization annealing or can be performed after the decarburization annealing is finished. According to a method in which decarburization is first performed and thereafter nitridation annealing is performed, precipitates such as Si ₃ N ₄ and (Si, Mn) N are formed. It is unstable and easily decomposed. As a result, it cannot function properly as an inhibitor, so that it can be changed to precipitates such as AlN and (Al ₅ , Si, Mn) N at a high temperature for a long time. However, if decarburization and nitridation annealing are performed at the same time, the above-described AlN and (Al, Si) N are formed at the same time, so a long processing time is not required. Therefore, a method of simultaneously performing decarburization and nitridation annealing is more preferable. However, it should be noted here that the method of performing nitridation annealing after decarburization can also be used as effectively as producing an electrical steel sheet having the advantageous characteristics of the present invention. That is, the simultaneous decarburizing and nitriding method is only simpler and more useful in the method for producing an electrical steel sheet of the present invention, and the present invention is not limited thereby.

  According to the research results of the inventors of the present invention, when the contents of Sn, Sb, and P are controlled within the range proposed in the present invention, the size factor of the crystal grains is greatly different from that of the conventional component system. Therefore, it is more preferable to consider this. That is, when the element content is controlled within the above-described range, not only the size of the primary recrystallized grains is reduced, but secondary recrystallization occurs well under the same primary recrystallization conditions. There may be no. If the primary recrystallized grains are refined, secondary recrystallization occurs well, but these elements also have the effect of preventing secondary recrystallization from occurring well under the same primary crystallization grain size. Therefore, after deciding whether the secondary recrystallization of the present invention occurs easily or less easily than in the conventional case, depending on which of these effects is more dominant, Must be applied to decarburization annealing conditions. According to the research results of the inventors of the present invention, the effect of increasing the driving force that promotes secondary recrystallization by refinement of the primary recrystallized grains is more dominant. It is more preferable to adjust the decarburization annealing temperature (that is, the primary recrystallization temperature) so that the size of the primary recrystallized organization does not become too fine. Therefore, it is preferable to set the decarburization annealing temperature to about 800 to 950 ° C., which is about 10 to 30 ° C. higher than usual. When the decarburization annealing temperature is low, not only a sufficient decarburization annealing effect does not occur, but also the crystal grains are maintained in a fine state, and crystal grains with an unfavorable orientation grow during secondary recrystallization. On the other hand, if the decarburization annealing temperature is too high, primary recrystallized grains may grow excessively. The preferred primary recrystallized grain size in the component system of the present invention is about 18 to 25 μm. Further, the dew point of the composition system of the present invention is advantageous for the management of the oxide layer so that the dew point is about 2 to 4 ° C. lower than the component system not containing Sn, Sb and P, and about 50 to 70 ° C. It is more advantageous for controlling grain orientation and improving iron loss in the final product.

  As described above, the steel sheet that has undergone the decarburization annealing is coated with an annealing separator containing MgO as a basic component, and then coiled into a final annealing for a long period of time, whereby Goth-oriented crystal grains are predominantly distributed. Manufactured into electrical steel sheets. The detailed process is as follows. In order to remove moisture from the annealing separator applied to the coiled steel sheet, a primary soaking process is performed, and then the primary recrystallized steel sheet is subjected to secondary recrystallization. A temperature raising process for raising the temperature for the purpose of heat treatment and a secondary soaking process for removing impurities in the steel at the same time as the recrystallization is further advanced later. At this time, in order to cause secondary recrystallization to begin within the limited temperature range while the inhibitor is re-dissolved instantaneously within the limited temperature, thereby eliminating the grain growth barrier. The temperature was increased while limiting the rate of temperature increase very slowly, and the secondary soaking time was set to a long period in order to remove impurities thereafter. Since such a conventional method causes a large decrease in productivity, the present inventors have analyzed the cause in many ways to solve such a problem, and as a result, the rate of temperature increase after primary soaking It was confirmed that it was preferable to apply the method in two stages.

  That is, even if the temperature is rapidly raised to a temperature below the temperature at which the inhibitor is dissolved, secondary recrystallization does not occur. If the temperature is increased at a slow cooling rate similar to the conventional one, the same secondary recrystallization effect can be obtained, while the required time is reduced, which is effective in improving productivity. In the present invention, the reference temperature to be applied by changing the temperature rising rate is set to 900 to 1020 ° C. That is, after the primary soaking, the temperature of the steel sheet is increased at a high temperature increase rate, and then the temperature is increased at a low temperature increase rate in consideration of the secondary recrystallization within the reference temperature range. In the present invention, the heating rate in the initial fast heating rate section is set to 18 to 75 ° C./hr, and the slow heating rate is set to 10 to 15 ° C./hr in consideration of secondary recrystallization. Further, in the present invention, the amount of nitrogen re-dissolved that acts as an inhibitor is limited as described above, and the total content of S is also limited to 0.0055% by weight or less to remove these components. The time required for the process can be shortened as compared with the conventional method.

  The primary soaking temperature and the secondary soaking temperature may be controlled within the normal soaking temperature, and are not particularly limited. However, examples of the primary soaking temperature may include a temperature range of 650 to 850 ° C., and examples of the secondary soaking temperature may include a range of 1150 to 1250 ° C. The range can be applied in small increments depending on the composition of the steel sheet or by changing other trivial parts other than the main features of the present invention.

  That is, the method for producing an electrical steel sheet according to the present invention comprises a step of reheating a steel slab having the above-described advantageous composition of the present invention; hot rolling, hot-rolled sheet annealing and annealing steel sheet cooling of the reheated steel slab. A step of hot rolling to produce a steel plate; a step of decarburizing and nitriding annealing the cold-rolled steel plate in a temperature range of 800 to 950 ° C .; and a final annealing of the annealed steel plate; When the final annealing stage includes a primary soaking stage, a temperature raising stage, and a secondary soaking stage, after the temperature raising temperature is initially raised at a temperature raising rate of 18 to 75 ° C./hr. The temperature is raised in the range of 10 to 15 ° C./hr within the range of 900 to 1020 ° C.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following examples are only for illustrating and embodying the present invention, and do not limit the scope of the present invention. It will be understood that they can be made equal and modified without departing from the spirit and scope of the invention.

<Iron loss change by Sn, Sb and P addition amount>
Wt.%, Si: 3.26%, C: 0.055%, Mn: 0.12%, Sol. Al: 0.026%, N: 0.0042%, S: 0.0045%, and the contents of Sn, Sb and P are changed as shown in Tables 1 to 4, and the remainder Fe and other impurities inevitably contained The grain-oriented electrical steel sheet containing a component was used. The slab of the electric steel sheet was heated for 210 minutes at a temperature of 1170 ° C. at which the amount of N dissolved again was 25 ppm, and then hot-rolled to produce a hot-rolled sheet having a thickness of 2.3 mm. The hot-rolled sheet was heated to 1120 ° C., maintained at 920 ° C. for 90 seconds, quenched in water and pickled, and then cold-rolled to a thickness of 0.30 mm to produce a cold-rolled sheet. In a furnace maintained at 875 ° C., a mixed gas of 75% hydrogen and 25% nitrogen having a dew point temperature of 63 ° C. and 1% dry ammonia gas were simultaneously charged, and cold-rolled sheets in the furnace Was maintained for 180 seconds, and decarburization and nitriding were performed simultaneously.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. During the final annealing, the primary soaking temperature is 700 ° C., the secondary soaking temperature is 1200 ° C., and the rate of temperature rise is 45 ° C./hr in the temperature range of 700 to 950 ° C., and 15 in the temperature range of 950 to 1200 ° C. C./hr. On the other hand, the soaking time at 1200 ° C. was 15 hours. The atmosphere at the time of final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C., and after reaching 1200 ° C., it was maintained in a 100% hydrogen atmosphere and then cooled in the furnace. The magnetic characteristics measured for each condition are as shown in Tables 1 to 4.

  In order to confirm the experimental results of Tables 1 to 4 more specifically, the results of confirming that the iron loss is different while changing Sn, Sb, and P in a state where other components are fixed, This is shown in FIGS. Among them, FIG. 4 is a graph showing the results of changing the Sn content with the Sb and P contents fixed. As can be seen from FIG. 4, when the Sb and P contents are out of the range defined in the present invention, the iron loss exhibited a continuous behavior without any special critical change, but Sb: 0.025, In the case of P: 0.035% by weight, Sb: 0.025, P: 0.04% by weight, the iron loss is drastically improved when Sn is 0.03 to 0.07% by weight. I was able to confirm that a certain point appeared. Therefore, when Sb was controlled to 0.03 to 0.7% by weight under the condition where Sb and P coexist, it was confirmed that the effect of reducing the iron loss exceeding the critical value was obtained.

  FIG. 5 is a graph showing that the iron loss changes depending on the Sb component in a state where the Sn and P components are fixed. When the Sn and P contents satisfy the range defined in the present invention, When the Sb content was controlled to 0.01 to 0.05% by weight, a remarkable iron loss improvement effect that could not be expected in the past appeared.

  FIG. 6 is also a graph showing that the iron loss changes depending on the P content in a state where Sn and Sb are fixed. When Sn and Sb satisfy the range defined in the present invention, the P content is reduced to 0.1%. When controlling to 01-0.05 weight%, the iron loss characteristic improved discontinuously.

  Therefore, when controlling Sn, Sb, and P within the range prescribed | regulated by this invention, it has confirmed that there was a remarkable iron loss reduction effect which cannot be anticipated conventionally.

  FIG. 7 is a diagram showing changes in iron loss due to the relationship between P and Sn when Sn is fixed at 0.05% by weight. FIG. 8 shows the relationship between P and Sn in FIG. It is a figure showing the effect that iron loss is improved when substituting 5Sb, but when the above formula P + 0.5Sb changes within the range of 0.0370 to 0.0630 defined in the present invention, It was confirmed that the loss was remarkably improved.

<Effect of controlling the amount of dissolved nitrogen during slab reheating>
By weight, Si: 3.23%, C: 0.058%, Mn: 0.12%, Al: 0.025%, P: 0.032%, N: 0.0053% and S: 0.00. An electric steel sheet containing 0042%, Sb: 0.032%, Sn: 0.045%, P: 0.038%, and the balance Fe and impurities inevitably contained was used. After changing the amount of N re-dissolved when reheating the slab of the steel sheet as shown in Table 5, hot rolling was performed to produce a hot-rolled sheet having a thickness of 2.3 mm. The hot-rolled sheet was heated to 1100 ° C., maintained at 920 ° C. for 90 seconds, quenched with water and pickled, and then cold-rolled to a thickness of 0.30 mm to produce a cold-rolled sheet. In a furnace maintained at 875 ° C., a mixed gas of 75% hydrogen and 25% nitrogen having a dew point temperature of 65 ° C. and 1% dry ammonia gas are simultaneously charged and cold rolled in the furnace. The plate was maintained for 180 seconds, and decarburization and nitriding were performed simultaneously.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. During the final annealing, the primary soaking temperature is 700 ° C., the secondary soaking temperature is 1200 ° C., and the rate of temperature rise is 45 ° C./hr in the temperature range of 700 to 950 ° C., and 15 in the temperature range of 950 to 1200 ° C. C./hr. The atmosphere during the final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C. After reaching 1200 ° C., the atmosphere was maintained in a 100% hydrogen atmosphere for 15 hours and then cooled in the furnace. The magnetic characteristics measured for each condition are shown in Table 5.

  As shown in Table 5 above, the inventive materials 25 to 27 in which the content of N re-dissolved during slab reheating satisfies the scope of the present invention are far superior in magnetic properties to the comparative materials 109 and 110. I understood.

<Effect of steel sheet thickness on iron loss>
In order to investigate the influence of the steel sheet thickness on iron loss, the following experiment was conducted.

  In weight percent, Si: 3.23%, C: 0.058%, Mn: 0.12%, Sol. Al: 0.025%, N: 0.0050%, S: 0.0045%, Sb: 0.032%, Sn: 0.045%, P: 0.038%, and the remainder Fe is unavoidably contained. Ingredient 1 containing impurities, Si: 3.25%, C: 0.054%, Mn: 0.11%, Sol. A direction including Al: 0.025%, N: 0.0050% and S: 0.0045%, the component system 2 including the remaining Fe and some impurities inevitably contained without including Sn, Sb and P Used electrical steel sheet. The slab of grain-oriented electrical steel sheet was heated for 210 minutes at a temperature of 1150 ° C. at which the content of N dissolved again was 23 ppm, and then hot-rolled to produce a hot-rolled sheet having a thickness of 2.3 mm. The hot-rolled sheet is heated to 1100 ° C., maintained at 920 ° C. for 90 seconds, quenched with water and pickled, and then cooled to a thickness of 0.35 mm, 0.30 mm, 0.27 mm, and 0.23 mm. Cold rolling was performed by hot rolling. In a furnace maintained at 875 ° C., a mixed gas of 75% hydrogen and 25% nitrogen having a dew point temperature of 63 ° C. and 1% dry ammonia gas are simultaneously charged and cold rolled in the furnace. The plate was maintained for 180 seconds, and decarburization and nitriding were performed simultaneously.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. During the final annealing, the primary soaking temperature is 700 ° C., the secondary soaking temperature is 1200 ° C., and the rate of temperature rise is 45 ° C./hr in the temperature range of 700 to 950 ° C., and 15 in the temperature range of 950 to 1200 ° C. C./hr. The atmosphere during the final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C. After reaching 1200 ° C., the atmosphere was maintained in a 100% hydrogen atmosphere for 15 hours and then cooled in the furnace. The magnetic characteristics measured for each condition are shown in Table 6.

  As shown in Table 6 above, the result of component system 1 to which Sb, Sn, and P are added has a significantly improved iron loss compared to component system 2 to which Sb, Sn, and P are not added. I was able to confirm. In addition, regardless of the component system, it can be confirmed that the iron loss is improved as the thickness of the steel sheet is reduced, and as a result, the inventive material having the component system defined in the present invention depends on the thickness of the steel sheet. The iron loss could be predicted, and the theoretical value of iron loss depending on the thickness of the steel sheet could be determined as shown in Equation 1 below.

(Formula 1)
Iron loss [W / kg] ≦ 0.46679 + 1.72222 * thickness [μm]

<Crystal orientation measurement>
Wt.%, Si: 3.18%, C: 0.0556%, Mn: 0.11%, Sol. Al: 0.026%, N: 0.0046%, S: 0.0045%, Sb: 0.028%, Sn: 0.046%, P: 0.037%, and the remainder Fe and other unavoidably contained The grain-oriented electrical steel sheet containing the impurities to be used was used. The slab of grain-oriented electrical steel sheet was heated for 210 minutes at a temperature of 1150 ° C. at which the amount of N to be re-dissolved was 21 ppm, and then hot-rolled to produce a hot-rolled sheet having a thickness of 2.3 mm. The hot-rolled sheet was heated to 1100 ° C., maintained at 920 ° C. for 90 seconds, quenched with water and pickled, and then cold-rolled to a thickness of 0.30 mm to produce a cold-rolled sheet. In a furnace maintained at 875 ° C., a mixed gas of 75% hydrogen and 25% nitrogen having a dew point temperature of 63 ° C. and 1% dry ammonia gas are simultaneously charged and cold rolled in the furnace. The plate was maintained for 180 seconds, and decarburization and nitriding were performed simultaneously.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. During the final annealing, the primary soaking temperature is 700 ° C., the secondary soaking temperature is 1200 ° C., and the rate of temperature rise is 45 ° C./hr in the temperature range of 700 to 950 ° C., and 15 in the temperature range of 950 to 1200 ° C. C./hr. The atmosphere during the final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C. After reaching 1200 ° C., the atmosphere was maintained in a 100% hydrogen atmosphere for 15 hours and then cooled in the furnace. Table 7 shows the magnetic properties measured for each condition and the area weighted average of β angle (angle between [001] orientation and RD with respect to TD axis).

  As shown in Table 7, when the Sb, Sn, and P contents are the inventive material controlled within the scope of the present invention, the degree of the crystal orientation deviating from the Goth orientation is less than 3 degrees. It was found that the characteristics were also excellent. That is, it was confirmed that the electrical steel sheet according to one embodiment of the present invention can produce a grain-oriented electrical steel sheet having excellent magnetic properties by controlling the orientation of secondary recrystallized grains.

<Modification of primary recrystallization method>
In order to investigate the influence on iron loss at the time of nitridation annealing after decarburization rather than simultaneous decarburization and nitriding annealing which is a more preferable method of the present invention, the following experiment was conducted.

  In weight percent, Si: 3.23%, C: 0.058%, Mn: 0.12%, Sol. Al: 0.025%, N: 0.0050%, S: 0.0045%, Sn: 0.045%, P: 0.038%, Sb is 0, 0.005, 0.025, 0 A grain-oriented electrical steel sheet containing different contents of 0.035 and 0.060% and containing the balance Fe and unavoidable impurities was used. The grain-oriented electrical steel slab was heated at a temperature of 1170 ° C. for 210 minutes at which the amount of N to be re-dissolved was 27 ppm, then re-heated and hot-rolled to obtain a hot-rolled sheet having a thickness of 2.3 mm. Manufactured. The hot-rolled sheet was heated to 1120 ° C., maintained at 920 ° C. for 90 seconds, quenched with water and pickled, and then cold-rolled to a thickness of 0.30 mm to produce a cold-rolled sheet. In a furnace maintained at 860 ° C., the cold rolled sheet was decarburized and annealed with a mixed gas of 75% hydrogen having a dew point temperature of 62 ° C. and 25% nitrogen. Thereafter, nitriding was performed with an N content of 200 ± 20 ppm.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. During the final annealing, the primary soaking temperature was 700 ° C., the secondary soaking temperature was 1200 ° C., and the heating rate was 15 ° C./hr over the entire heating temperature range. The atmosphere during the final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C. After reaching 1200 ° C., the atmosphere was maintained in a 100% hydrogen atmosphere for 15 hours and then cooled in the furnace. Thereafter, normal tension coating and planarization were performed. Table 8 shows the magnetic characteristics measured for each condition.

  As shown in Table 8 above, the results of the inventive material (component system 1) with the appropriate amounts of Sb, Sn and P are compared to the comparative material (component system 2) which does not contain the appropriate amounts of Sb, Sn and P. It was confirmed that the iron loss was greatly improved. Further, it has been found that when primary recrystallization is performed in the decarburization treatment before the nitriding method, the iron loss is critically improved in the content range of the component of the present invention.

<Iron loss change by As addition>
In weight percent, Si: 3.15%, C: 0.058%, Mn: 0.1%, Sol. Al: 0.03%, N: 0.0049%, S: 0.004%, Sn: 0.05%, Sb: 0.032%, P: 0.04%, As is shown in 9 below The grain-oriented electrical steel sheet containing the remaining Fe and other impurities inevitably contained was used. A slab of grain-oriented electrical steel sheet was heated at 1170 ° C. for 210 minutes and then hot-rolled to produce a hot-rolled sheet having a thickness of 2.3 mm. The hot-rolled sheet was heated to 1120 ° C., maintained at 910 ° C. for 90 seconds, quenched with water and pickled, and then cold-rolled to a thickness of 0.30 mm to produce a cold-rolled sheet. In a furnace maintained at 875 ° C., a mixed gas of 75% hydrogen and 25% nitrogen having a dew point temperature of 62 ° C. and 1% dry ammonia gas are simultaneously charged and cold-rolled in the furnace. The plate was maintained for 180 seconds, and decarburization and nitriding were performed simultaneously.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. At the time of final annealing, the primary soaking temperature is 700 ° C., the secondary soaking temperature is 1200 ° C., and the rate of temperature rise is 45 ° C./hr in the temperature range of 700 to 45 ° C./hr and the temperature range of 950 to 1200 ° C. Then, it was set to 15 ° C./hr. On the other hand, the soaking time at 1200 ° C. was 15 hours. The atmosphere at the time of final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C. After reaching 1200 ° C., it was maintained in a 100% hydrogen atmosphere and then cooled in the furnace. Table 9 shows the magnetic characteristics measured for each condition.

  As shown in Table 9, a case where the addition amount of As satisfies the range defined in the present invention is defined as an invention material for convenience, and a case where it is outside this is defined as a comparative material. In Table 9 above, the inventive material 41 to the inventive material 43 represent the case where As is added in the content range defined in the present invention, and the comparative material 121 represents the case where the content of As is excessive. In the case of the inventive material, it was confirmed that the iron loss decreased as As was added. However, in the case of the comparative material 121 in which the amount of As added is excessive, it was confirmed that the iron loss rather increased and adversely affected the improvement of the iron material.

  Therefore, it was confirmed that the above As is advantageously added to 1.40% by weight or less.

<Iron loss change due to Cu addition>
Wt%, Si: 3.0%, C: 0.052%, Mn: 0.12%, Sol. Al: 0.026%, N: 0.0042%, S: 0.0045%, Sn: 0.05%, Sb: 0.027%, P: 0.039%, Cu is shown in Table 10 below A grain-oriented electrical steel sheet was used which was added at the indicated different contents and contained the remainder Fe and other unavoidable impurities. The slab of grain-oriented electrical steel sheet was heated at 1170 ° C. for 210 minutes at which the amount of N dissolved again was 25 ppm, and then hot-rolled to produce a hot-rolled sheet having a thickness of 2.3 mm. The hot-rolled sheet was heated to 1120 ° C., maintained at 910 ° C. for 90 seconds, quenched with water and pickled, and then cold-rolled to a thickness of 0.30 mm to produce a cold-rolled sheet. In a furnace maintained at 875 ° C., a mixed gas of 75% hydrogen and 25% nitrogen having a dew point temperature of 62 ° C. and 1% dry ammonia gas are simultaneously charged and cold-rolled in the furnace. The plate was maintained for 180 seconds, and decarburization and nitriding were performed simultaneously.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. At the time of final annealing, the primary soaking temperature is 700 ° C., the secondary soaking temperature is 1200 ° C., and the rate of temperature rise is 45 ° C./hr in the temperature range of 700 to 45 ° C./hr and the temperature range of 950 to 1200 ° C. Then, it was set to 15 ° C./hr. On the other hand, the soaking time at 1200 ° C. was 15 hours. The atmosphere at the time of final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C., and after reaching 1200 ° C., it was maintained in a 100% hydrogen atmosphere and then cooled in the furnace. Table 10 shows the magnetic characteristics measured for each condition.

  As shown in Table 10, the case where the addition amount of each element satisfies the range defined in the present invention is defined as an invention material for convenience, and the case where it is outside this is defined as a comparative material. In Table 10 above, the inventive material 44 to the inventive material 48 represent the case where Cu is added to the range defined by the present invention, and the comparative material 122 represents the case where the Cu content is excessive. In particular, the inventive materials 45 to 48 represent a case where Cu is added in a more preferable range defined by the present invention, that is, 0.05% by weight or more, and the inventive material 44 is a case where Cu is added less than the above range. Represents. Inventive material 44 with a relatively low Cu content exhibited a level of iron loss similar to that of a general component system in which no Cu was added, but in the case of inventive materials 45 to 48 with an increased amount of Cu added, It was possible to confirm that the decrease in was more remarkable. However, in the case of the comparative material 122 having an excessive amount of added Cu, it was confirmed that the iron loss increased rather, which adversely affected the improvement of the iron loss.

  Therefore, it was confirmed that the Cu was advantageously added to 0.50% by weight or less.

<Iron loss change by Bi addition>
In weight percent, Si: 3.15%, C: 0.058%, Mn: 0.1%, Sol. Al: 0.03%, N: 0.0049%, S: 0.004%, Sn: 0.05%, Sb: 0.032%, P: 0.04%, Bi is shown in Table 11 below A grain-oriented electrical steel sheet was used which was added at the indicated different contents and contained the remainder Fe and other unavoidable impurities. A slab of grain-oriented electrical steel sheet was heated at 1170 ° C. for 210 minutes and then hot-rolled to produce a hot-rolled sheet having a thickness of 2.3 mm. The hot-rolled sheet was heated to 1120 ° C., maintained at 910 ° C. for 90 seconds, quenched with water and pickled, and then cold-rolled to a thickness of 0.30 mm to produce a cold-rolled sheet. In a furnace maintained at 875 ° C., a mixed gas of 75% hydrogen and 25% nitrogen having a dew point temperature of 62 ° C. and 1% dry ammonia gas are simultaneously charged and cold-rolled in the furnace. The plate was maintained for 180 seconds, and decarburization and nitriding were performed simultaneously.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. At the time of final annealing, the primary soaking temperature is 700 ° C., the secondary soaking temperature is 1200 ° C., and the rate of temperature rise is 45 ° C./hr in the temperature range of 700 to 45 ° C./hr and the temperature range of 950 to 1200 ° C. Then, it was set to 15 ° C./hr. On the other hand, the soaking time at 1200 ° C. was 15 hours. The atmosphere at the time of final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C., and after reaching 1200 ° C., it was maintained in a 100% hydrogen atmosphere and then cooled in the furnace. Table 11 shows the magnetic characteristics measured for each condition.

  As shown in Table 11, a case where the amount of Bi added satisfies the range defined in the present invention was defined as an invention material for convenience, and a case where it was outside this range was defined as a comparative material. In Table 11 above, the inventive material 49 to the inventive material 52 represent the case where Bi is added within the range specified in the present invention, and the comparative material 123 represents the case where the Bi content is excessive. In the case of the inventive material, it was confirmed that the iron loss decreased as Bi was added. However, in the case of the comparative material 123 with an excessive amount of Bi added, it was confirmed that the iron loss increased rather, which adversely affected the improvement of the iron loss.

  Therefore, it was confirmed that the Bi was advantageously added to 0.1% by weight or less.

<Iron loss change due to Te addition>
In weight percent, Si: 3.15%, C: 0.058%, Mn: 0.1%, Sol. Al: 0.03%, N: 0.0049%, S: 0.004%, Sn: 0.05%, Sb: 0.032%, P: 0.04%, Te is shown in Table 12 below A grain-oriented electrical steel sheet was used which was added at the indicated different contents and contained the remainder Fe and other unavoidable impurities. A slab of grain-oriented electrical steel sheet was heated at 1170 ° C. for 210 minutes and then hot-rolled to produce a hot-rolled sheet having a thickness of 2.3 mm. The hot-rolled sheet was heated to 1120 ° C., maintained at 910 ° C. for 90 seconds, quenched with water and pickled, and then cold-rolled to a thickness of 0.30 mm to produce a cold-rolled sheet. In a furnace maintained at 875 ° C., a mixed gas of 75% hydrogen and 25% nitrogen having a dew point temperature of 62 ° C. and 1% dry ammonia gas are simultaneously charged and cold-rolled in the furnace. The plate was maintained for 180 seconds, and decarburization and nitriding were performed simultaneously.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. At the time of final annealing, the primary soaking temperature is 700 ° C., the secondary soaking temperature is 1200 ° C., and the rate of temperature rise is 45 ° C./hr in the temperature range of 700 to 45 ° C./hr and the temperature range of 950 to 1200 ° C. Then, it was set to 15 ° C./hr. On the other hand, the soaking time at 1200 ° C. was 15 hours. The atmosphere at the time of final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C., and after reaching 1200 ° C., it was maintained in a 100% hydrogen atmosphere and then cooled in the furnace. Table 12 shows the magnetic characteristics measured for each condition.

  As shown in Table 12, the case where the addition amount of each element satisfies the range defined in the present invention is defined as an invention material for convenience, and the case where it is outside this range is defined as a comparative material. In Table 12 above, the inventive material 53 to the inventive material 56 represent the case where Te is added within the range defined by the present invention, and the comparative material 124 represents the case where the Te content is excessive. In the case of the inventive material, it was confirmed that the iron loss decreased as Te was added. However, in the case of the comparative material 124 in which the amount of Te added is excessive, it was confirmed that the iron loss rather increased and adversely affected the improvement of the iron loss.

  Therefore, it was confirmed that the Te is advantageously added to 1.40% by weight or less.

<Iron loss change due to Ni addition>
By weight, Si: 3.1%, C: 0.051%, Mn: 0.1%, Sol. Al: 0.026%, N: 0.0041%, S: 0.005%, Sn: 0.045%, Sb: 0.028%, P: 0.038%, Ni is shown in Table 13 below. A grain-oriented electrical steel sheet was used which was added at the indicated different contents and contained the remainder Fe and other unavoidable impurities. A slab of grain-oriented electrical steel sheet was heated at 1170 ° C. for 210 minutes and then hot-rolled to produce a hot-rolled sheet having a thickness of 2.3 mm. The hot-rolled sheet was heated to 1120 ° C., maintained at 910 ° C. for 90 seconds, quenched with water and pickled, and then cold-rolled to a thickness of 0.30 mm to produce a cold-rolled sheet. In a furnace maintained at 875 ° C., a mixed gas of 75% hydrogen and 25% nitrogen having a dew point temperature of 62 ° C. and 1% dry ammonia gas are simultaneously charged and cold-rolled in the furnace. The plate was maintained for 180 seconds, and decarburization and nitriding were performed simultaneously.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. At the time of final annealing, the primary soaking temperature is 700 ° C., the secondary soaking temperature is 1200 ° C., and the rate of temperature rise is 45 ° C./hr in the temperature range of 700 to 45 ° C./hr and the temperature range of 950 to 1200 ° C. Then, it was set to 15 ° C./hr. On the other hand, the soaking time at 1200 ° C. was 15 hours. The atmosphere at the time of final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C., and after reaching 1200 ° C., it was maintained in a 100% hydrogen atmosphere and then cooled in the furnace. Table 13 shows the magnetic properties measured for each condition.

  As shown in Table 13, the case where the addition amount of Ni satisfies the range defined in the present invention is defined as an invention material for convenience, and the case where it is outside this range is defined as a comparative material. In Table 13 above, the inventive material 57 to the inventive material 60 represent the case where Ni was added within the range defined by the present invention, and the comparative material 125 represents the case where the Ni content is excessive. In the case of the inventive material, it was confirmed that the iron loss decreased as Ni was added. However, in the case of the comparative material 125 having an excessive amount of added Ni, it was confirmed that the iron loss increased rather, which adversely affected the improvement of the iron loss.

  Therefore, it was confirmed that the Ni was advantageously added to 1.40% by weight or less.

<Iron loss change due to Cr addition>
In weight percent, Si: 3.105%, C: 0.057%, Mn: 0.09%, Sol. Al: 0.027%, N: 0.0051%, S: 0.005%, Sn: 0.05%, Sb: 0.031%, P: 0.037%, Cr is shown in Table 14 below A grain-oriented electrical steel sheet was used which was added at the indicated different contents and contained the remainder Fe and other unavoidable impurities. A slab of grain-oriented electrical steel sheet was heated at 1170 ° C. for 210 minutes and then hot-rolled to produce a hot-rolled sheet having a thickness of 2.3 mm. The hot-rolled sheet was heated to 1120 ° C., maintained at 910 ° C. for 90 seconds, quenched with water and pickled, and then cold-rolled to a thickness of 0.30 mm to produce a cold-rolled sheet. In a furnace maintained at 875 ° C., a mixed gas of 75% hydrogen and 25% nitrogen having a dew point temperature of 62 ° C. and 1% dry ammonia gas are simultaneously charged and cold-rolled in the furnace. The plate was maintained for 180 seconds, and decarburization and nitriding were performed simultaneously.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. At the time of final annealing, the primary soaking temperature is 700 ° C., the secondary soaking temperature is 1200 ° C., and the rate of temperature rise is 45 ° C./hr in the temperature range of 700 to 45 ° C./hr and the temperature range of 950 to 1200 ° C. Then, it was set to 15 ° C./hr. On the other hand, the soaking time at 1200 ° C. was 15 hours. The atmosphere at the time of final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C., and after reaching 1200 ° C., it was maintained in a 100% hydrogen atmosphere and then cooled in the furnace. Table 14 shows the magnetic characteristics measured for each condition.

  As shown in Table 14, the case where the addition amount of each element satisfies the range defined in the present invention is defined as an invention material for convenience, and the case where it is outside this range is defined as a comparative material. In Table 14 above, the inventive material 61 to the inventive material 65 represent the case where Cr is added within the range defined by the present invention, and the comparative material 126 represents the case where the Cr content is excessive. In particular, the inventive materials 62 to 65 represent the case where Cr is added in a more preferable range defined by the present invention, that is, 0.05% by weight or more, and the inventive material 61 represents the case where it is added less than the above range. . Inventive material 61 having a relatively low Cr content exhibited a level of iron loss similar to that of a general component system in which no Cr was added, but in the case of inventive materials 62 to 65 in which the amount of Cr added was increased, the iron loss was reduced. It was possible to confirm that the decrease in was more remarkable. However, in the case of the comparative material 126 with an excessive amount of Cr added, it was confirmed that the iron loss increased rather, which adversely affected the improvement of the iron loss.

  Therefore, it was confirmed that the Cr was advantageously added to 0.35% by weight or less.

<Iron loss change by adding Pb>
Wt.%, Si: 3.12%, C: 0.055%, Mn: 0.11%, Sol. Al: 0.029%, N: 0.0049%, S: 0.0045%, Sn: 0.05%, Sb: 0.031%, P: 0.039%, Pb is shown in Table 15 below A grain-oriented electrical steel sheet was used which was added at the indicated different contents and contained the remainder Fe and other unavoidable impurities. A slab of grain-oriented electrical steel sheet was heated at 1170 ° C. for 210 minutes and then hot-rolled to produce a hot-rolled sheet having a thickness of 2.3 mm. The hot-rolled sheet was heated to 1120 ° C., maintained at 910 ° C. for 90 seconds, quenched with water and pickled, and then cold-rolled to a thickness of 0.30 mm to produce a cold-rolled sheet. In a furnace maintained at 875 ° C., a mixed gas of 75% hydrogen and 25% nitrogen having a dew point temperature of 62 ° C. and 1% dry ammonia gas are simultaneously charged, and cold-rolled sheets are used in the furnace. Was maintained for 180 seconds, and decarburization and nitriding were performed simultaneously.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. At the time of final annealing, the primary soaking temperature is 700 ° C., the secondary soaking temperature is 1200 ° C., and the rate of temperature rise is 45 ° C./hr in the temperature range of 700 to 45 ° C./hr and the temperature range of 950 to 1200 ° C. Then, it was set to 15 ° C./hr. On the other hand, the soaking time at 1200 ° C. was 15 hours. The atmosphere at the time of final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C., and after reaching 1200 ° C., it was maintained in a 100% hydrogen atmosphere and then cooled in the furnace. Table 15 shows the magnetic characteristics measured for each condition.

  As shown in Table 15, the case where the amount of Pb added satisfies the range defined in the present invention is defined as an invention material for convenience, and the case where it is outside this is defined as a comparative material. In Table 15 above, the inventive material 66 to the inventive material 69 represent the case where Pb was added within the range defined by the present invention, and the comparative material 127 represents the case where the Pb content is excessive. In the case of the inventive material, it was confirmed that the iron loss decreased as Pb was added. However, in the case of the comparative material 127 with an excessive amount of Pb added, it was confirmed that the iron loss increased rather, which adversely affected the improvement of the iron loss.

  Therefore, it was confirmed that the Pb was advantageously added to 1.40% by weight or less.

<Change in iron loss due to addition of at least one selected from Mo, B, Ge, Nb, Ti and Zn>
In weight percent, Si: 3.15%, C: 0.058%, Mn: 0.1%, Sol. Al: 0.03%, N: 0.0049%, S: 0.004%, Sn: 0.05%, Sb: 0.032%, P: 0.04%, Mo, B, Ge, One element selected from the group consisting of Nb, Ti and Zn is added at different wet contents in Table 16 below, and the grain-oriented steel sheet containing the remainder Fe and other unavoidable impurities is used. did. A slab of grain-oriented electrical steel sheet was heated at 1170 ° C. for 210 minutes and then hot-rolled to produce a hot-rolled sheet having a thickness of 2.3 mm. The hot-rolled sheet was heated to 1120 ° C., maintained at 910 ° C. for 90 seconds, quenched with water and pickled, and then cold-rolled to a thickness of 0.30 mm to produce a cold-rolled sheet. In a furnace maintained at 875 ° C., a mixed gas of 75% hydrogen and 25% nitrogen having a dew point temperature of 62 ° C. and 1% dry ammonia gas are simultaneously charged and cold-rolled in the furnace. The plate was maintained for 180 seconds, and decarburization and nitriding were performed simultaneously.

  Next, MgO which is an annealing separator was applied to the heat-annealed steel sheet and finally annealed into a coil shape. At the time of final annealing, the primary soaking temperature is 700 ° C., the secondary soaking temperature is 1200 ° C., and the rate of temperature rise is 45 ° C./hr in the temperature range of 700 to 45 ° C./hr and the temperature range of 950 to 1200 ° C. Then, it was set to 15 ° C./hr. On the other hand, the soaking time at 1200 ° C. was 15 hours. The atmosphere at the time of final annealing was a mixed atmosphere of 25% nitrogen + 75% hydrogen up to 1200 ° C. After reaching 1200 ° C., the atmosphere was maintained in a 100% hydrogen atmosphere and then cooled in the furnace. Table 16 shows the magnetic properties measured for each condition.

  As shown in Table 16, the case where the addition amount of each element satisfies the range defined in the present invention is defined as an invention material for convenience, and the case where it is outside this range is defined as a comparative material. In Table 16 above, the inventive material 70 to the inventive material 72 represent the case where Mo is added within the range defined by the present invention, and the comparative material 128 represents the case where the Mo content is excessive. In particular, the inventive materials 71 and 72 represent a more preferable range defined in the present invention, that is, the case where Mo is added to 0.003% by weight or more, and the inventive material 70 represents a case where the addition is less than the above range. . Inventive material 70 having a relatively low Mo content exhibited iron loss at a level similar to that of a general component system in which no Mo was added, but in the case of inventive materials 71 and 72 in which the amount of added Mo was increased, the iron loss was reduced. It was possible to confirm that the decrease in was more remarkable. However, in the case of the comparative material 128 having an excessive amount of added Mo, it was confirmed that the iron loss increased rather, which adversely affected the improvement of the iron loss.

  Inventive Material 73 to Inventive Material 75 and Comparative Material 129 represent the results of observing the effect of B on iron loss improvement, and Inventive Material 76 to Inventive Material 78 and Comparative Material 130 are about iron loss improvement. The results of observing the influence of Ge are shown. Inventive material 79 to inventive material 81 and comparative material 131 are the results of observing the influence of Zn on the improvement of iron loss, and the inventive materials 82 to 82 are shown. Inventive material 84 and comparative material 131 show the results of observing the effect of Nb on iron loss improvement, and inventive material 85 to inventive material 87 and comparative material 132 show the influence of Ti on iron loss improvement. Although there was a slight difference in the reduction of iron loss values between steels, it was confirmed that the inventive material and the comparative material showed similar effects in reducing iron loss. I was able to.

  Therefore, the additive element is advantageously added to 1.40% by weight or less, and in order to obtain a more reliable effect of improving iron loss, it is more advantageous to add 0.003% by weight or more. I was able to confirm that there was.

Claims (13)

  A grain-oriented electrical steel sheet comprising Sn: 0.03-0.07 wt%, Sb: 0.01-0.05 wt% and P: 0.01-0.05 wt% as essential components.   The grain-oriented electrical steel sheet according to claim 1, wherein P + 0.5Sb is in a range of 0.0370 to 0.0630 (where P and S mean the content (% by weight) of the corresponding element).   As: 1.40 wt% or less, Cu: 0.50 wt% or less, Bi: 0.1 wt% or less, Te: 1.40 wt% or less, Ni: 1.40 wt% or less, Cr: 0.35 % By weight or less, Pb: 1.40% by weight or less, and at least one selected from the group consisting of Mo, B, Ge, Nb, Ti, and Zn: one kind in total of 1.40% by weight or less Or the grain-oriented electrical steel sheet of Claim 1 or 2 which further contains 2 or more types.   The direction according to claim 1 or 2, further comprising Si: 2.0 to 4.0 wt%, acid-soluble Al: 0.020 to 0.040 wt%, and Mn: 0.01 to 0.20 wt%. Electrical steel sheet.   The grain-oriented electrical steel sheet according to claim 1 or 2, wherein an area weighted average calculated from an absolute value of a β angle, which is a degree in which a crystal orientation of the electrical steel sheet deviates from a Goss orientation, is less than 3 degrees.   3. Directional electricity according to claim 1 or 2, manufactured from a steel slab further comprising C: 0.04-0.07 wt%, N: 10-55 ppm and S: 0.0010-0.0055 wt%. steel sheet. A steel slab containing Sn: 0.03-0.07 wt%, Sb: 0.01-0.05 wt% and P: 0.01-0.05 wt% as essential components is hot-rolled, annealed and cooled. A step of hot rolling to produce a steel plate;
Decarburizing and nitriding annealing the cold-rolled steel sheet at a temperature range of 800 to 45 ° C./hr; and finally annealing the annealed steel sheet;
In the case where the final annealing stage includes a primary soaking stage, a temperature raising stage, and a secondary soaking stage, after the temperature raising temperature is initially raised at a temperature raising rate of 18 to 75 ° C./hr. The manufacturing method of the steel plate which heats up in the range of 10-15 degree-C / hr within the range of 900-1020 degreeC.   The manufacturing method of the steel plate of Claim 7 whose range of P + 0.5Sb is 0.0370-0.0630 (here, P and S mean the content (weight%) of an applicable element).   The steel slab is composed of As: 1.40% by weight or less, Cu: 0.50% by weight or less, Bi: 0.1% by weight or less, Te: 1.40% by weight or less, Ni: 1.40% by weight or less, Cr: 0.35 wt% or less, Pb: 1.40 wt% or less, and at least one selected from the group consisting of Mo, B, Ge, Nb, Ti, and Zn: 1.40 wt% in total The manufacturing method of the steel plate of Claim 7 or 8 which further contains 1 type (s) or 2 or more types among the following.   The steel slab is composed of Si: 2.0 to 4.0 wt%, acid-soluble Al: 0.020 to 0.040 wt%, Mn: 0.01 to 0.20 wt%, C: 0.04 to 0 The manufacturing method of the steel plate of Claim 7 or 8 which further contains 0.07 weight%, N: 10-55 ppm, and S: 0.0010-0.0055%.   The method of manufacturing a steel sheet according to claim 7 or 8, wherein the step of reheating the steel slab controls the heating temperature so that the content of N to be re-dissolved is in a range of 10 to 40 ppm.   The heating temperature of the steel slab is a manufacturing method of the steel plate according to claim 11 which is the range of 1050-1250 ° C.   The method for producing a steel sheet according to claim 7 or 8, wherein the secondary soaking temperature is in a range of 1150 to 1250 ° C.

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