JP2005187846A - Non-oriented electromagnetic steel sheet and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-oriented electromagnetic steel sheet which, though containing much C, has such magnetic properties of an iron core as not to deteriorate by aging due to a temperature rise of the iron core during the operation of an electrical machinery and apparatus. <P>SOLUTION: In order to achieve the object, the non-oriented electromagnetic steel sheet comprises, by mass%, 0.0026-0.010% C, 4.0% or less Si, 0.10-2.0% Mn, 0.20% or less P, 0.006% or less S, 0.20-3.0% Al, 0.0020% or more but less than 0.040% V, 0.003% or less Ti, 0.0050% or less N, 0.010% or less B, 0.20% or less Sn+Sb, 0.010% or less Ca and the balance substantially Fe with unavoidable impurities. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a non-oriented electrical steel sheet applied to iron cores such as motors and transformers, and a method for manufacturing the same. In particular, non-oriented electrical steel sheets suitable for iron cores such as compressor motors and induction motors that are hot during operation, and power steering motors that are desired to have high hysteresis during operation and low hysteresis loss, and the like. It relates to a manufacturing method.

  From the viewpoints of preventing global warming and promoting energy saving, various electric devices are being made highly efficient and downsized. In order to increase the efficiency and miniaturization of electrical equipment, it is effective to improve the magnetic properties of the electrical steel sheet that is the core material.

  Conventionally, the magnetic properties of electrical steel sheets have been measured at room temperature by the Epstein method or the like before product shipment. However, during actual electrical equipment operation, since the temperature of the iron core may rise to 150 ° C. to 200 ° C., there is a problem that the magnetic properties of the iron core deteriorate due to the aging effect.

  It is known that it is effective to suppress the precipitation of carbides such as cementite and ε carbide, which are the cause of deterioration, against such deterioration of magnetic properties due to aging. For this reason, efforts have been made to reduce the amount of C contained in the electromagnetic steel sheet to the limit.

  For example, Non-Patent Document 1 describes that aging deterioration is suppressed by reducing the amount of solute C in steel to 0.0030% or less. However, this is related to iron loss at relatively high magnetic fields (eg, 1.5 T). On the other hand, the aging deterioration of the iron loss in a low magnetic field (for example, 1.0 T or less) is more remarkable and cannot be sufficiently suppressed in the present situation.

  Patent Document 1 discloses a manufacturing method that suppresses aging degradation. This method is characterized in that after annealing the steel at 650 ° C. to 900 ° C., the steel is rapidly cooled at a cooling rate exceeding 1000 ° C./s, and then subjected to an overaging treatment at 300 ° C. to 550 ° C. for 60 seconds or more. It is. According to this method, there is a problem that the flatness of the steel sheet deteriorates during rapid cooling, and the production efficiency decreases due to the overaging treatment.

NKK Technical Report, 131 (1990), 16 JP-A 64-55337

  The present invention has been made in view of the above problems, and provides a non-oriented electrical steel sheet in which aging deterioration of core magnetic properties due to a rise in core temperature during operation of electrical equipment is reduced even when the C content is high. The main purpose is to provide.

  In order to solve the above-described problems, the present invention provides, in mass%, C: 0.0026% to 0.010%, Si: 4.0% or less, Mn: 0.10% to 2.0%, P: 0 20% or less, S: 0.006% or less, Al: 0.20% to 3.0%, V: 0.0020% to less than 0.040%, Ti: 0.003% or less, N: 0.0. 0050% or less, B: 0.010% or less, Sn + Sb: 0.20% or less, Ca: 0.010% or less, the balance being substantially composed of Fe and inevitable impurities An electrical steel sheet is provided.

  In the non-oriented electrical steel sheet according to the present invention, by containing a predetermined amount of V as a steel component, precipitation and growth of precipitates such as cementite and ε carbide are suppressed even after aging treatment. Thereby, the iron loss deterioration by aging is prevented.

Further, in the present invention, by mass, C: 0.0026% to 0.010%, Si: 4.0% or less, Mn: 0.10% to 2.0%, P: 0.20% or less S: 0.006% or less, Al: 0.20% to 3.0%, V: 0.0020% to less than 0.040%, Ti: 0.003% or less, N: 0.0050% or less, B: 0.010% or less, Sn + Sb: 0.20% or less, Ca: 0.010% or less, with the balance being substantially composed of Fe and inevitable impurities. ) To Equation (3) are provided, and a method for producing a non-oriented electrical steel sheet is provided, which includes hot rolling, cold rolling, and finish annealing.
Steel ingot or billet heating temperature = 1050 ° C. to 1250 ° C. (1)
Hot rolling end temperature = 700 ° C. to 950 ° C. (2)
Finish annealing temperature ≧ 800 ° C (3)

  In the manufacturing method of the non-oriented electrical steel sheet according to the present invention, since the heating temperature of the steel is limited to 1050 ° C. to 1250 ° C., hot rolling is facilitated without increasing the deformation resistance of the steel, AlN and MnS do not precipitate finely during hot rolling of steel.

  Moreover, since the hot rolling end temperature is limited to 700 ° C. to 950 ° C., generation of oxide scale on the surface of the hot-rolled steel sheet is suppressed, so that descaling is facilitated in the subsequent pickling.

  Moreover, since the finish annealing temperature is limited to 800 ° C. or more, the crystal grain size in the steel is increased, and the iron loss of the steel is reduced.

  Further, by containing a predetermined amount of V as a steel component, precipitation and growth of precipitates such as cementite and ε carbide are suppressed even after aging treatment. Thereby, the iron loss deterioration by aging is prevented.

Furthermore, in the present invention, by mass, C: 0.0026% to 0.010%, Si: 4.0% or less, Mn: 0.10% to 2.0%, P: 0.20% or less S: 0.006% or less, Al: 0.20% to 3.0%, V: 0.0020% to less than 0.040%, Ti: 0.003% or less, N: 0.0050% or less, B: 0.010% or less, Sn + Sb: 0.20% or less, Ca: 0.010% or less, with the balance being substantially composed of Fe and inevitable impurities. ) To Equation (4) are provided, and a method for producing a non-oriented electrical steel sheet is provided, wherein hot rolling, hot rolled sheet annealing, cold rolling and finish annealing are performed.
Steel ingot or billet heating temperature = 1050 ° C. to 1250 ° C. (1)
Hot rolling end temperature = 700 ° C. to 950 ° C. (2)
Hot-rolled sheet annealing temperature = 750 ° C. to 1100 ° C. (4)
Finish annealing temperature ≧ 800 ° C (3)

  In the manufacturing method of the non-oriented electrical steel sheet according to the present invention, since the heating temperature of the steel is limited to 1050 ° C. to 1250 ° C., hot rolling is facilitated without increasing the deformation resistance of the steel, AlN and MnS do not precipitate finely during hot rolling of steel.

  Moreover, since the hot rolling end temperature is limited to 700 ° C. to 950 ° C., generation of oxide scale on the surface of the hot-rolled steel sheet is suppressed, so that descaling is facilitated in the subsequent pickling.

  Furthermore, since the hot-rolled sheet annealing temperature is limited to 750 ° C to 1100 ° C, the grain size of the hot-rolled sheet does not become too large and breakage during cold rolling is prevented and the magnetic properties of the steel are improved. To do.

  Moreover, since the finish annealing temperature is limited to 800 ° C. or more, the crystal grain size in the steel is increased, and the iron loss of the steel is reduced.

  Furthermore, by containing a predetermined amount of V as a steel component, precipitation and growth of precipitates such as cementite and ε carbide are suppressed even after aging treatment. Thereby, the iron loss deterioration by aging is prevented.

  According to the present invention, by containing a predetermined amount of V as a steel component, precipitation and growth of precipitates such as cementite and ε carbide are suppressed even after aging treatment. Thereby, the iron loss deterioration by aging is prevented.

  The present invention includes a non-oriented electrical steel sheet and a manufacturing method thereof. Hereinafter, each will be described in detail. “%” Indicating the content of each element in the steel means “% by mass” unless otherwise specified.

  Further, in the present invention, “the balance is substantially composed of Fe and inevitable impurities” means that it contains a case where other elements are contained within a range that does not impair the effects of the present invention.

A. First, the non-oriented electrical steel sheet of the present invention will be described.

  The non-oriented electrical steel sheet of the present invention is, in mass%, C: 0.0026% to 0.010%, Si: 4.0% or less, Mn: 0.10% to 2.0%, P: 0.00. 20% or less, S: 0.006% or less, Al: 0.20% to 3.0%, V: 0.0020 to less than 0.040%, Ti: 0.003% or less, N: 0.0050% Hereinafter, B: 0.010% or less, Sn + Sb: 0.20% or less, Ca: 0.010% or less is contained, and the balance is substantially composed of Fe and inevitable impurities.

First, the knowledge that led to the present invention and the experimental results that lead to it will be described. Inventors measured the deterioration rate of the low magnetic field iron loss _{W10 / 50} of the various electrical steel sheets age-treated at 200 _degreeC for 100 hours. Since carbide precipitation is presumed to be the main cause of aging deterioration, the inventors searched for a component that suppresses carbide precipitation and does not affect magnetic property deterioration. As a result, it became clear for the first time that a steel sheet having good magnetic properties and little aging deterioration can be obtained by adding V or adding V and B in combination. Next, the verification experiment will be described in detail.

First, in a vacuum melting furnace, main components are C: 0.0040%, Si: 1.0%, Mn: 0.20%, P: 0.09%, S: 0.003%, Al: 0.30. %, N: 0.0020%, Ti: 0.002% or less, Sn: 0.001% or less, Sb: 0.001% or less, Ca: 0.0002% or less, and the V content is 0.0010. A cast slab was produced in which the content of B was changed from 0.05% to 0.050% and the B content was changed from less than 0.0001% to 0.0015%. Next, these slabs were heated to 1100 ° C., and hot-rolled steel sheets having a thickness of 3 mm were prepared under 850 ° C. finishing conditions. These steel plates are ground to a thickness of 2.3 mm, cold-rolled to a thickness of 0.5 mm, and subjected to a final annealing at 950 ° C. for 30 seconds to produce a single plate test piece having a width of 30 mm and a length of 100 mm. The iron loss W _10/50 before and after aging treatment at 200 ° C. for 100 hours was measured.

  FIG. 1 shows the relationship between the iron loss deterioration rate and the V content in the steel sheet. As is clear from FIG. 1, it is understood that aging deterioration is suppressed when the V content in the steel sheet is 0.0020% or more. Moreover, it turns out that the aging characteristic of the steel plate with V content 0.0020% or more and B content 0.0006% or more is further improved.

  FIG. 2 shows the relationship between the iron loss and the V content in the steel sheet. As is clear from FIG. 2, when the V content in the steel sheet is 0.04% or more, it can be seen that the magnetic properties themselves before aging deteriorate. Although the reason for the effect of suppressing aging deterioration due to V in the steel sheet is not clear, the present inventors presume as follows.

  When a steel having a C content of 0.0026% or more is subjected to an aging treatment for a long time, solid solution C in the steel precipitates as cementite, ε carbide, and the like. Since these precipitates inhibit the domain wall movement, the iron loss of the steel increases. However, the steel containing V is presumed that the iron loss of the steel does not deteriorate because precipitation and growth of cementite, ε carbide and the like are suppressed. However, when the V content in the steel is 0.040% or more, VC is precipitated, so that the magnetic properties of the steel deteriorate. On the other hand, B in the steel segregates at the grain boundaries in the steel and suppresses the formation of carbides, so it is estimated that the iron loss of the steel does not deteriorate.

  From the above, it was found that the deterioration of magnetic properties due to aging can be reduced by containing a predetermined amount of V as a steel component.

  In the present invention, it is characterized by containing a predetermined amount of V as a steel component. However, in order to effectively bring out the effect and satisfy other characteristics necessary for the electromagnetic steel sheet, the steel component is added as described later. Must be limited. Hereinafter, the steel component in the non-oriented electrical steel sheet of the present invention will be described.

1. Steel composition ・ C
C in the steel forms carbides such as cementite and ε-carbide by aging, and causes deterioration of the magnetic properties of the steel due to aging. Therefore, it is necessary to reduce the C content in the steel. Aging deterioration is completely suppressed if the C content in steel is reduced to less than 0.0026%, but all C content in mass-produced electrical steel sheets is efficiently reduced to less than 0.0026%. It is not easy to make it happen. On the other hand, when the C content in the steel exceeds 0.010%, the effect of the V addition of the present invention is not sufficient, and the magnetic properties before aging are deteriorated. From the above, the C content in steel is limited to 0.0026% or more and 0.010% or less. Furthermore, in order to improve the aging deterioration of steel, it is preferable to set the upper limit of the C content in the steel to 0.0070%.

・ Si
Si in steel increases the specific resistance of steel and is effective in reducing iron loss of steel. What is necessary is just to determine Si content in steel according to a required iron loss characteristic. However, if the Si content in the steel exceeds 4.0%, the steel easily breaks during cold rolling, so that the manufacturing cost of the steel increases remarkably. From the above, the Si content in the steel is limited to 4.0% or less. In addition, in order to improve the iron loss of steel, it is preferable to make Si content in steel 1.0% or more.

・ Mn
Mn in steel increases the specific resistance of steel and is effective in reducing iron loss of steel. However, the effect of Mn is smaller than the effect of Si. Moreover, when Mn content in steel exceeds 2.0%, raw material cost will become high. On the other hand, when the Mn content in the steel is reduced to less than 0.10%, MnS is finely dispersed in the steel, so that the magnetic properties of the steel deteriorate. From the above, the Mn content in the steel is limited to the range of 0.10% or more and 2.0% or less.

・ P
Since P in steel is an unavoidable impurity, it is not particularly necessary to add it. However, when the P content in the steel is 0.040% or more, the texture of the steel product is improved and the magnetic flux density is improved. Moreover, even if the P content in the steel is 0.040% or more, the aging characteristics of the steel are hardly affected. Therefore, the P content in steel may be 0.040% or more as necessary. However, if the P content in the steel exceeds 0.20%, the toughness of the steel deteriorates, so that the steel may be broken during cold rolling. From the above, the P content in steel is limited to 0.20% or less.

・ S
Since S in steel is an inevitable impurity, it is not necessary to add it in particular. However, if the S content in the steel exceeds 0.006%, a large amount of MnS is formed in the steel, so that the magnetic properties of the steel deteriorate. Therefore, it is necessary to reduce the S content in steel. From the above, the S content in steel is limited to 0.006% or less. In particular, in order to improve the iron loss characteristics, the S content in steel is preferably 0.003% or less.

・ Al
Al in steel is an element effective for deoxidation and increases the specific resistance of steel in the same manner as Si, and is therefore effective in reducing iron loss of steel. However, if the Al content in the steel is less than 0.20%, AlN, VN and the like are finely precipitated in the steel, so that the magnetic properties of the steel deteriorate. On the other hand, when the Al content in the steel exceeds 3.0%, the saturation magnetic flux density of the steel is remarkably lowered, so that the core performance is deteriorated. From the above, the Al content in the steel is limited to 0.20% or more and 3.0% or less. In addition, in order to improve the magnetic flux density of steel, it is preferable to make the upper limit of Al content in steel 1.0%.

・ V
V in the steel is an essential element in the present invention, and has an effect of reducing deterioration of the magnetic properties of the steel due to aging. However, when the V content in the steel is less than 0.0020%, aging deterioration of the steel cannot be suppressed at all. On the other hand, if the V content in the steel is 0.040% or more, VC precipitates in the steel, and the magnetic properties of the steel deteriorate. From the above, the V content in steel is limited to 0.0020% or more and less than 0.040%. Note that the V content in steel in which the effect of suppressing aging is most remarkable is 0.0090% or more and 0.030% or less.

・ Ti
Since Ti in steel is an unavoidable impurity, it is not particularly necessary to add it. When the Ti content in the steel exceeds 0.003%, precipitates such as TiN, TiS, and TiC are finely dispersed in the steel, so that the magnetic properties of the steel deteriorate. Therefore, the Ti content in the steel is limited to 0.003% or less.

・ N
Since N in steel is an unavoidable impurity, it is not particularly necessary to add it. If the N content in the steel exceeds 0.0050%, a large amount of AlN is dispersed in the steel, so that the magnetic properties of the steel deteriorate. Therefore, the N content in the steel is limited to 0.0050% or less.

・ B
B in the steel is not an essential element in the present invention, but has the effect of further improving the aging characteristics by being added in combination with V. In order to obtain the effect, the B content in steel needs to be 0.0006% or more. Moreover, when B content in steel exceeds 0.010%, a coarse B compound will be produced | generated in steel and there exists a possibility that steel may fracture | rupture at the time of cold rolling. In view of the above, the B content in steel is preferably 0.0006% or more and 0.010% or less.

・ Sn + Sb
Sn and Sb in the steel are not essential elements in the present invention, but the addition increases the magnetic flux density of the steel without inducing aging deterioration of the steel. In order to improve the magnetic flux density of steel, the total of Sn and Sb contents in steel needs to be 0.010% or more. However, if the total content of Sn and Sb in the steel exceeds 0.20%, the toughness of the steel is remarkably deteriorated, so that the steel may be broken during cold rolling. From the above, the total content of Sn and Sb in the steel is limited to 0.20% or less. Moreover, in order to improve the magnetic flux density of steel, it is preferable to make the total of Sn and Sb content in steel 0.010% or more as needed.

・ Ca
Ca in steel does not need to be added in particular. Ca in the steel does not affect the aging characteristics of the steel. On the other hand, when Ca content in steel becomes 0.0005% or more, it coarsens oxides, sulfides, and the like, thereby improving the magnetic properties of steel. However, since steel containing 0.010% or more of Ca deteriorates toughness, there is a risk of cracking in the steel during cooling or heating. From the above, the Ca content in the steel is limited to 0.010% or less. In order to improve magnetic properties, the Ca content in steel is preferably 0.0005% or more.

B. Next, a method for producing a non-oriented electrical steel sheet according to the present invention will be described.

The 1st manufacturing method of the non-oriented electrical steel sheet of this invention is the mass%. C: 0.0026% -0.010%, Si: 4.0% or less, Mn: 0.10% -2.0 %, P: 0.20% or less, S: 0.006% or less, Al: 0.20% to 3.0%, V: 0.0020% to less than 0.040%, Ti: 0.003% or less , N: 0.0050% or less, B: 0.010% or less, Sn + Sb: 0.20% or less, Ca: 0.010% or less, with the balance being substantially made of Fe and inevitable impurities Alternatively, the steel slab is characterized by being hot-rolled, cold-rolled and finish-annealed under the conditions satisfying the following formulas (1) to (3).
Steel ingot or billet heating temperature = 1050 ° C. to 1250 ° C. (1)
Hot rolling end temperature = 700 ° C. to 950 ° C. (2)
Finish annealing temperature ≧ 800 ° C (3)

  The steel ingot or steel slab is manufactured as a slab as follows, for example. First, the molten steel decarburized and desulfurized in a converter is put into a ladle, and the ladle is moved to an RH type vacuum degassing apparatus. Next, in the RH vacuum degassing apparatus, the molten steel is decarburized until the C concentration in the molten steel becomes 0.0040% or less. Next, the contents of Si, Mn, P, Al, V, B, Sn, Sb and Ca in the molten steel are adjusted, and the molten steel is made into a slab with a continuous casting machine.

  Next, the slab is heated in a heating furnace. Slab heating is necessary to reduce the hot deformation resistance of the slab and to roll to a predetermined thickness. When the slab heating temperature is less than 1050 ° C., the deformation resistance of the slab is high and hot rolling becomes difficult. On the other hand, when the slab heating temperature exceeds 1250 ° C., AlN and MnS are dissolved and reprecipitated during hot rolling of the slab. Since many of these precipitates are finely dispersed in the slab, the magnetic properties of the steel product deteriorate. Therefore, the slab heating temperature is limited to 1050 ° C. or more and 1250 ° C. or less.

  The slab is then hot rolled. In this case, the hot rolling end temperature is an important condition for improving the magnetic properties by controlling the structure of the hot rolled sheet. If the hot rolling end temperature is less than 700 ° C., the recrystallization rate of the hot-rolled steel sheet microstructure is almost 0%, so that the magnetic flux density of the steel product is significantly reduced. This is because a texture that is advantageous for the magnetic properties of steel cannot be obtained. On the other hand, if the hot rolling finish temperature exceeds 950 ° C., the oxide scale on the surface of the hot-rolled steel sheet grows thick, and it becomes difficult to remove the scale in pickling in the subsequent steps. Therefore, the hot rolling end temperature is limited to 700 ° C. or higher and 950 ° C. or lower.

  Next, the steel sheet is pickled and descaled, cold-rolled, and then subjected to finish annealing. If necessary, an insulating film is applied to the steel plate surface. Finish annealing is very important to control the iron loss of steel products. Since the iron loss decreases as the particle size increases, the finish annealing temperature should be higher. When the finish annealing temperature is less than 800 ° C., the iron loss cannot be sufficiently reduced. Therefore, the finish annealing temperature is limited to 800 ° C. or higher. In addition, V, which is an essential element of the present invention, increases the recrystallization temperature of steel, so that the finish annealing temperature should be higher. In order to further improve the iron loss of the non-oriented electrical steel sheet of the present invention, the finish annealing temperature is preferably 900 ° C. or higher. The upper limit of the finish annealing temperature is not particularly limited, but if it exceeds 1150 ° C., the refractory damage of the annealing furnace becomes severe, so that the manufacturing cost is remarkably increased. Therefore, the finish annealing temperature is more preferably 1150 ° C. or lower.

The 2nd manufacturing method of the non-oriented electrical steel sheet of this invention is the mass%. C: 0.0026% -0.010%, Si: 4.0% or less, Mn: 0.10% -2.0 %, P: 0.20% or less, S: 0.006% or less, Al: 0.20% to 3.0%, V: 0.0020% to less than 0.040%, Ti: 0.003% or less , N: 0.0050% or less, B: 0.010% or less, Sn + Sb: 0.20% or less, Ca: 0.010% or less, with the balance being substantially made of Fe and inevitable impurities Alternatively, the steel slab is subjected to hot rolling, hot-rolled sheet annealing, cold rolling, and finish annealing under conditions that satisfy the following formulas (1) to (4).
Steel ingot or billet heating temperature = 1050 ° C. to 1250 ° C. (1)
Hot rolling end temperature = 700 ° C. to 950 ° C. (2)
Hot-rolled sheet annealing temperature = 750 ° C. to 1100 ° C. (4)
Finish annealing temperature ≧ 800 ° C (3)

  In the second manufacturing method of such a non-oriented electrical steel sheet, as in the first manufacturing method, the slab is heated and then hot rolled to obtain a steel sheet. Next, hot-rolled sheet annealing is performed after pickling the steel sheet. Alternatively, the pickling descaling is performed after the hot-rolled sheet annealing. Hot-rolled sheet annealing is effective in improving the magnetic properties of steel. In order to sufficiently obtain the effect of the magnetic properties of steel, the hot-rolled sheet annealing temperature needs to be 750 ° C. or higher. On the other hand, when the hot-rolled sheet annealing temperature exceeds 1100 ° C., the particle size of the hot-rolled sheet becomes too large, so that the steel sheet tends to break during cold rolling of the steel sheet. Therefore, the hot-rolled sheet annealing temperature is limited to 750 ° C. or higher and 1100 ° C. or lower.

  Next, similarly to the first method for producing the non-oriented electrical steel sheet, the steel sheet is cold-rolled and then subjected to finish annealing. If necessary, an insulating film is applied to the steel plate surface.

(Example 1)
230 ton of molten steel decarburized and desulfurized in a converter was put into a ladle, and the ladle was moved to an RH type vacuum degasser. Next, decarburization was performed in the RH vacuum degassing apparatus until the C concentration in the molten steel became 0.0040% or less. Next, the contents of Si, Mn, P, Al, V, B, Sn, Sb and Ca in the molten steel were adjusted, and the molten steel was made into a slab with a continuous casting machine.

  Next, the slab was heated to 1150 ° C. in a heating furnace and hot-rolled at a finishing temperature of 850 ° C. to 880 ° C. and a winding temperature of 500 ° C. to a thickness of 2.0 mm. Next, after pickling and descaling, it was cold-rolled to a thickness of 0.5 mm and subjected to finish annealing at 900 ° C. to 1020 ° C. After finish annealing, an insulating film was applied to the steel sheet surface. A 28 cm Epstein test piece was collected from this steel plate, and after aging treatment at 200 ° C. for 100 hours, the iron loss and magnetic flux density were measured by the method defined in JIS-C-2550.

  The steel plate of Examples 1-1 to 1-8 has a V content of 0.0020% or more, and the steel plates of Comparative Example 1-1 and Comparative Example 1-2 have components so that the V content is less than 0.0020%. It has been adjusted.

(Evaluation 1)
The component analysis values of the steel plates of Examples 1-1 to 1-8, Comparative Example 1-1, and Comparative Example 1-2 are shown in Table 1, Examples 1-1 to 1-8, Comparative Example 1-1, and Comparison The magnetic property measurement results of the steel sheet of Example 1-2 are shown in Table 2, FIG. 3 and FIG.

  As shown in Table 2 and FIG. 3, the steel sheets of Examples 1-1 to 1-8 and the steel sheets of Comparative Example 1-1 and Comparative Example 1-2 have the same magnetic properties. However, as shown in Table 2 and FIG. 4, the steel sheets of Examples 1-1 to 1-8 are less subject to aging deterioration than the steel sheets of Comparative Example 1-1 and Comparative Example 1-2. In addition, it can be seen that, with respect to aging deterioration, the more the V content in the steel sheet, the more effective the reduction of aging deterioration of the steel sheet, and the more effective by adding V and B to the steel sheet in combination. It has been confirmed that the addition of Sn, Sb, Ca, etc. to the steel plate to improve the magnetic properties does not particularly affect the aging properties.

(Example 2)
230 ton of molten steel decarburized and desulfurized in a converter was put into a ladle, and the ladle was moved to an RH type vacuum degasser. Next, decarburization was performed in the RH vacuum degassing apparatus until the C concentration in the molten steel became 0.0040% or less. Next, the contents of Si, Mn, P, Al, V, B, Sn, Sb and Ca in the molten steel were adjusted, and the molten steel was made into a slab with a continuous casting machine.

  Next, the slab was heated to 1150 ° C. in a heating furnace and hot-rolled at a finishing temperature of 850 ° C. to 880 ° C. and a winding temperature of 500 ° C. to a thickness of 2.0 mm. Next, after pickling, annealing was performed at 800 ° C. for 10 hours, cold rolling to a thickness of 0.35 mm, and finish annealing was performed at 1020 ° C. to 1080 ° C. After finish annealing, an insulating film was applied to the steel sheet surface. A 28 cm Epstein test piece was collected from this steel plate, and after aging treatment at 200 ° C. for 100 hours, the iron loss and magnetic flux density were measured by the method defined in JIS-C-2550.

  The steel plates of Examples 2-1 to 2-8 have a V content of 0.0020% or more, and the steel plates of Comparative Examples 2-1 and 2-2 have components so that the V content is less than 0.0020%. It has been adjusted.

(Evaluation 2)
The component analysis values of the steel plates of Examples 2-1 to 2-8, Comparative Example 2-1 and Comparative Example 2-2 are shown in Table 3, Examples 2-1 to 2-8, Comparative Example 2-1 and Comparative Example The measurement results of the magnetic properties of the steel sheet of Example 2-2 are shown in Table 4, FIG. 5 and FIG.

  As shown in Table 4, FIG. 5 and FIG. 6, the steel sheets of Examples 2-1 to 2-8 have better magnetic properties than the steel sheets of Comparative Example 2-1 and Comparative Example 2-2. In addition, aging deterioration is small. In addition, Example 2-8, which has a relatively high V content, is slightly inferior in magnetic properties to Comparative Examples 2-1 and 2-2, but has good aging properties. It has been confirmed that the addition of Sn, Sb, Ca, etc. to the steel plate to improve the magnetic properties does not particularly affect the aging properties.

It is a graph which shows the relationship between an iron loss deterioration rate and V content in a steel plate. It is a graph which shows the relationship between an iron loss and V content in a steel plate. It is a graph which shows the relationship between an iron loss and V content in a steel plate. It is a graph which shows the relationship between an iron loss deterioration rate and V content in a steel plate. It is a graph which shows the relationship between an iron loss and V content in a steel plate. It is a graph which shows the relationship between an iron loss deterioration rate and V content in a steel plate.

Claims (3)

In mass%, C: 0.0026% to 0.010%, Si: 4.0% or less, Mn: 0.10% to 2.0%, P: 0.20% or less, S: 0.006% Hereinafter, Al: 0.2% to 3.0%, V: 0.0020% to less than 0.040%, Ti: 0.003% or less, N: 0.0050% or less, B: 0.010% or less Sn + Sb: 0.20% or less, Ca: 0.010% or less, the balance being substantially composed of Fe and inevitable impurities, a non-oriented electrical steel sheet, In mass%, C: 0.0026% to 0.010%, Si: 4.0% or less, Mn: 0.10% to 2.0%, P: 0.20% or less, S: 0.006% Hereinafter, Al: 0.2% to 3.0%, V: 0.0020% to less than 0.040%, Ti: 0.003% or less, N: 0.0050% or less, B: 0.010% or less Sn + Sb: 0.20% or less, Ca: 0.010% or less, and a steel ingot or steel slab consisting essentially of Fe and inevitable impurities, the following formulas (1) to (3) A method for producing a non-oriented electrical steel sheet, characterized by hot rolling, cold rolling, and finish annealing under satisfying conditions.
Steel ingot or billet heating temperature = 1050 ° C. to 1250 ° C. (1)
Hot rolling end temperature = 700 ° C. to 950 ° C. (2)
Finish annealing temperature ≧ 800 ° C (3) In mass%, C: 0.0026% to 0.010%, Si: 4.0% or less, Mn: 0.10% to 2.0%, P: 0.20% or less, S: 0.006% Hereinafter, Al: 0.20% to 3.0%, V: 0.0020% to less than 0.040%, Ti: 0.003% or less, N: 0.0050% or less, B: 0.010% or less Sn + Sb: 0.20% or less, Ca: 0.010% or less, and a steel ingot or steel slab consisting essentially of Fe and inevitable impurities, the following formula (1) to formula (4) A method for producing a non-oriented electrical steel sheet, characterized by hot rolling, hot-rolled sheet annealing, cold rolling and finish annealing under satisfying conditions.
Steel ingot or billet heating temperature = 1050 ° C. to 1250 ° C. (1)
Hot rolling end temperature = 700 ° C. to 950 ° C. (2)
Hot-rolled sheet annealing temperature = 750 ° C. to 1100 ° C. (4)
Finish annealing temperature ≧ 800 ° C (3)

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