JP2009155731A - Unidirectional electromagnetic steel sheet which has high magnetic flux density and is excellent in high magnetic field iron loss - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a unidirectional electromagnetic steel sheet having a high magnetic flux density and a low iron loss at excitation magnetic flux density. <P>SOLUTION: The unidirectional electromagnetic steel sheet has a composition comprising, (1) by weight, ≤0.005% C, 2.0-7.0% Si, ≤0.2% Mn, ≤0.065% Al, ≤0.005% N, ≤0.005% in total of S and/or Se and the balance being Fe and unavoidable impurities. Here, the crystal orientation of the steel sheet shows an average deviation angle of ≤5° from ä110}<001> ideal orientation, the average of 180° magnetic domain width of the steel sheet is ≤0.26 mm, the ratio of W<SB>19/50</SB>to W<SB>17/50</SB>is ≤1.84, and W<SB>19/50</SB>is ≤1.84. The unidirectional electromagnetic steel sheet further comprises, (2) by weight, one or more of Sb, Sn, Cu, Mo, Ge, B, Te, As, Cr and Bi in an amount of 0.003-0.3% each. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a grain-oriented electrical steel sheet for use in transformer cores and the like.

Unidirectional electrical steel sheets are mainly used as core materials for transformers and generators. This steel sheet is subjected to finish annealing in the manufacturing process, and a low iron loss is obtained as a structure highly accumulated in the {110} <001> orientation, so-called Goth orientation, using secondary recrystallization. The iron loss of the _grain- oriented electrical steel sheet is evaluated according to JIS C 2553 by W _17/50 (energy loss under an excitation condition of B ₈ 1.7T, 50 Hz) and graded.

There are two types of transformer cores: a wound core and a stacked core. In the wound core and the stacked core, a design magnetic flux density higher than 1.7 T, for example, about 1.9 T is used to reduce the size of the transformer. There is a case.
In stacked iron cores, steel plates are laminated on the “day” and “eye” molds to form an iron core. Therefore, even if the designed magnetic flux density of the iron core is 1.7 T, the iron core locally has a magnetic flux density of 1.7 T or more. Therefore, for example, W _{19/50 of} 1.7 T or more greatly affects the transformer iron loss.
Recently, from the viewpoint of conservation of the global environment and energy saving, a directional electrical steel sheet with even less iron loss has been demanded from the market, and in particular, a steel sheet with less iron loss even in a high magnetic field such as 1.9 T is demanded.

In the following Patent Document 1, the average crystal grain is 1 to 10 mm, and the crystal orientation has a deviation of 8 ° or less in the rolling direction as an average value with respect to the ideal orientation of (110) [001]. Although the characteristic unidirectional electrical steel sheet is described, W _19/50 Is not described at all, and there is no description about the domain width.

Non-Patent Document 1 describes an example of a sample in which the orientation accumulation degree in {110} <001> is 3 degrees and 7 degrees on average in FIGS. 1A and 1B. _19/50 Is not described at all. Fig. 2 shows B8 and hysteresis loss Wh _15/50 , Wh _17/50 It is a relationship. B8 and total iron loss W _15/50 , W _17/50 The relationship diagram of is not described at all. _19/50 There is no description about.

JP-A-7-268567

Taguchi et al., “About Orient Core Hi-Bi”, “Ryokan Research”, Nippon Steel Corporation, published on October 25, 1972, No. 276, pages 135-143.

Conventionally, inventions and improvements have been made over the years to reduce the iron loss W _17/50 . However, in view of the recent situation as described above, it is an object of the present invention to provide a high magnetic flux density unidirectional electrical steel sheet that is higher than 1.7 T and has a low iron loss of the excitation magnetic flux density.

The present invention is summarized as follows in order to solve the above problems.
(1) By weight%
C: 0.005% or less,
Si: 2.0-7.0%,
Mn: 0.2% or less,
Al: 0.065% or less,
N: 0.005% or less,
Total of one or two of S and Se: 0.005% or less, the balance is composed of Fe and inevitable impurities, and the crystal orientation of the steel sheet is relative to the ideal orientation of {110} <001> W _19/50 / W _17/50 : 1.84 or less, characterized in that the average value is a deviation of orientation of 5 degrees or less, and the average 180-degree magnetic domain width of the steel sheet is 0.26 mm or less. And W _19/50 : 1.36 or less unidirectional electrical steel sheet.
( 2 ) It is characterized by further containing 0.003 to 0.3% by weight percent of one or more of Sb, Sn, Cu, Mo, Ge, B, Te, As, Cr and Bi, respectively. The unidirectional electrical steel sheet according to (1) .

  ADVANTAGE OF THE INVENTION According to this invention, the high magnetic flux density unidirectional electrical steel plate excellent in the high magnetic field iron loss can be provided, and the industrial effect is very large.

The figure which shows the 180 degree | times magnetic domain width measuring method. The figure which shows distribution of 180 degree | times magnetic domain width of a sample (1) and a sample (2). The figure which shows the relationship between 180 degree _| times magnetic domain width, and _{W17 / 50} . The figure which shows the relationship between a 180-degree magnetic domain width and _{W19 / 50} . The figure which shows the relationship between a 180-degree magnetic domain width and _W19 / ₅₀ / _W17 / ₅₀ . The figure which shows the relationship between the deviation angle of the average of {110} <001> direction, and _W19 / ₅₀ / _W17 / ₅₀ .

Details of the present invention will be described below.
As a result of intensive studies to develop a unidirectional electrical steel sheet with a small W _19/50, the present inventors have found that it is very effective to highly control the crystal orientation shift and the 180-degree magnetic domain width. I found it.
This inventor changed the manufacturing process conditions of a high magnetic flux density unidirectional electrical steel sheet variously, and manufactured the thing with low and high _{W19 / 50} . C: 0.002% by weight (hereinafter abbreviated as%), Si: 3.25%, Mn: 0.07%, S: 0.001%, Al: 0.01%, T. N: 0.001%, Sn: 0.11%, Cu: 0.07% included, plate thickness 0.23mm, the crystal orientation of the steel sheet deviates by 3 degrees on average from {110} <001> The survey results of the samples with are shown below.

Sample (1) is W _17/50 : 0.70 W / kg, W _19/50 : 1.20 W / kg, Sample (2) is W _17/50 : 0.77 W / kg, W _19/50 : 1 49 W / kg.
In order to elucidate this difference in iron loss, the inventors focused on the 180-degree magnetic domain width. The iron loss is generally divided into hysteresis loss, classical eddy current loss, and abnormal eddy current loss, and the abnormal eddy current loss accounts for about 40% of the total iron loss. In the case of grain-oriented electrical steel sheets, it is known that abnormal eddy current loss increases in proportion to the 180-degree magnetic domain width.

For 180-degree domain width, quantified the relationship between crystal orientation and 180-degree domain width in single crystals in T. Nozawa et al .: IEEE Trans. Mag. No. 4, MAG-14 (1978), p.252. There are reports.
However, there is no example of quantifying the 180-degree magnetic domain width of polycrystalline unidirectional electrical steel sheet products. It is well known that the 180-degree magnetic domain width is narrowed by applying scratches to the steel sheet, laser irradiation, and grooving with a tooth profile roll. Absent.

Therefore, the present inventors have devised quantification of the 180-degree magnetic domain width of a polycrystalline high magnetic flux density unidirectional electrical steel sheet by the following method. FIG. 1 shows the method.
First, a 180 degree magnetic domain was made to appear in the steel plate sample by the bitter method. Thereafter, a 5 mm square was put on and the number of 180-degree magnetic domains was measured for each square. One sample was measured for 190 mm, and the average and distribution of the magnetic domain width of 190 mm were obtained and used as the measured value of the sample. In total, the number of 180 degree magnetic domains of about 2000 was measured for one sample, and the 180 degree magnetic domain width was quantified.
-Magnetic domain width of 1 mm = number of magnetic domains of 5 mm / 180 degrees-Average magnetic domain width of the sample = average of magnetic domain width of 190 mm

Next, the 180-degree magnetic domain width of samples (1) and (2) was compared using this method. FIG. 2 shows the distribution of magnetic domain widths of samples (1) and (2). In FIG. 2, the vertical width of the magnetic domain width indicates the upper limit of the range. For example, 0.2 is 0 to 0.2 or less, and 0.4 is more than 0.2 mm to 0.4 mm or less. In this comparison, the average magnetic domain width was 0.26 mm for sample (1) and 0.32 mm for sample (2). From this, it was found that the average of the 180-degree magnetic domain width differs greatly between the samples (1) and (2).

The experimental result which investigated the relationship between 180 degree _| times magnetic domain width, iron loss _{W17 / 50,} and _{W19 / 50} is shown.
C: 0.002%, Si: 3.25%, Mn: 0.07%, S: 0.001%, Al: 0.01%, T.I. N: 0.001%, Sn: 0.11%, Cu: 0.07%, and a product having a plate thickness of 0.23 mm was prepared by various manufacturing methods. The average of 180-degree magnetic domain width and iron loss W _{17 / 50} and W _19/50 were measured. The average deviation angle of the {110} <001> orientation was 3 degrees.

FIG. 3 _shows the relationship between the average 180 ° magnetic domain width and W _17/50 , and FIG. 4 shows the relationship between the average 180 ° magnetic domain width and W _19/50 . FIG. 5 shows the relationship between the average of the 180-degree magnetic domain width and W _19/50 / W _17/50 . W _19/50 / W _17/50 means the degree of deterioration of W _19/50 relative to W _17/50 .
180 mean and _W of the magnetic domain width _{17/50, W 19/50} is a good correlation, it can be seen that the higher the average 180 ° magnetic domain width becomes narrower _{W 17/50,} it is _{W 19/50} lowered. Further, it has been found that W _19/50 / W _17/50 becomes smaller as the average of 180-degree magnetic domain width becomes narrower, and that the high-field iron loss becomes particularly good as the average of 180-degree magnetic domain width becomes narrower.

FIG. 6 shows C: 0.002%, Si: 3.25%, Mn: 0.07%, S: 0.001%, Al: 0.01%, T.I. N: 0.001%, Sn: 0.11%, Cu: 0.07%, a product having a plate thickness of 0.23 mm was prepared by various manufacturing methods, and the average 180-degree magnetic domain width was 0.25-0.25. It is the result of investigating the relationship between the average deviation angle of {110} <001> orientation and W _19/50 / W _17/50 for a 0.26 mm sample.
The average deviation angle of the {110} <001> orientation is an average value measured by the Laue method and 40 secondary recrystallized grains. From this, it can be seen that a low W _19/50 / W _17/50 can be obtained when the deviation angle is 5 degrees or less.

Next, the reason for limitation of the high magnetic flux density unidirectional electrical steel sheet excellent in the high magnetic field iron loss of the present invention will be described. The following components are weight percentages contained in the steel.
If C exceeds 0.005%, the magnetic properties of the product deteriorate due to magnetic aging, so 0.005% or less was set.

  If Si is less than 2.0% lower limit, eddy current loss increases and good iron loss cannot be obtained, and if it exceeds 7.0% upper limit, the workability is remarkably deteriorated, so 2.0 to 7.0%. To do.

  Mn contains 0.2% or less. Inhibitors MnS and MnSe are formed in the production process and remain in the steel after S and Se are purified by high-temperature annealing, and the upper limit is 0.2%.

  One or a total of two selected from S and Se forms inhibitors MnS and MnSe and remains in the steel after S and Se are purified by high-temperature annealing, and 0.005% or less. Including. If it exceeds 0.005%, the iron loss will deteriorate.

  Al forms the inhibitor AlN in the manufacturing process and remains in the steel after N is purified by high-temperature annealing, and includes 0.065% or less. AlN may not be used as an inhibitor.

  N forms the inhibitor AlN in the manufacturing process and remains in the steel after N is purified by high-temperature annealing, and includes 0.005% or less. If it exceeds 0.005%, the iron loss will deteriorate. AlN may not be used as an inhibitor.

  One or more elements selected from Sb, Sn, Cu, Mo, Ge, B, Te, As, Cr and Bi may be added as necessary as an inhibitor and grain boundary segregation, and 0.003 each. ˜0.3% or less is contained.

If the average of the 180-degree magnetic domain width of the steel sheet exceeds 0.26 mm from FIG. 5, the high magnetic field iron loss cannot be reduced. Moreover, if the deviation angle of the crystal orientation of the steel sheet is an average value with respect to the ideal orientation of {110} <001> and exceeds 5 degrees from FIG. 6, the high magnetic field iron loss cannot be lowered.
The high magnetic flux density unidirectional electrical steel sheet of the present invention usually has a primary film mainly composed of forsterite or spinel and an insulating film (secondary film) on its surface. However, there is no problem even if there is neither a primary film nor a secondary film, only a primary film, only a secondary film without a primary film, or a TiN film by ion plating or the like as an insulating film.

Next, a method for producing about excellent high magnetic flux density grain-oriented electrical steel sheet high magnetic field core loss of the present invention. First, the components of a hot-rolled coil or a coil cast directly from molten steel will be described.
If C is less than 0.015% of the lower limit, secondary recrystallization becomes unstable. If the upper limit of 0.100% is greater than C, decarburization time becomes longer, which is economically disadvantageous. Limited to.

  If the lower limit of Si is less than 2%, good iron loss cannot be obtained. If the upper limit of 7% is exceeded, the cold-rolling property is remarkably deteriorated, so 2.0 to 7.0%.

  If Mn is less than 0.03% in the lower limit, hot embrittlement occurs, and if it exceeds 0.2% in the upper limit, the magnetic properties are deteriorated, so 0.03 to 0.2%.

  S and Se are elements necessary for forming MnS and MnSe. If the total of one or two of these is less than 0.005%, the absolute amount of MnS and MnSe is insufficient, and the upper limit is 0.050%. If it exceeds, hot cracking occurs, and purification by final finish annealing becomes difficult, so 0.005 to 0.050%.

  Sol. Al is an element effective for forming AlN. If the lower limit is less than 0.010%, the absolute amount of AlN is insufficient, and if it exceeds 0.065%, an appropriate dispersion state of AlN cannot be obtained. AlN may not be used as an inhibitor.

  N is an element effective for forming AlN. If the lower limit is less than 0.0040%, the absolute amount of AlN is insufficient, and if it exceeds 0.0100%, an appropriate dispersion state of AlN cannot be obtained. AlN may not be used as an inhibitor.

  Sb, Sn, Cu, Mo, Ge, B, Te, As, Cr, and Bi stabilize secondary recrystallization as an inhibitor and grain boundary segregation, but when each content is less than 0.003%, the segregation amount The upper limit of 0.3% is for economic reasons and prevention of decarburization. One element may be added, or two or more elements may be added.

  Molten steel is cast into slabs or directly into steel strips. When cast into a slab, the coil is finished by a normal hot rolling method. Steel strip or hot-rolled coil is subjected to hot-rolled sheet annealing and final cold rolling, or pre-cold rolling, precipitation annealing, final strong rolling, or hot-rolled sheet annealing, preliminary cold rolling, precipitation annealing, and final strong cold rolling. Through this process, the final thickness is obtained, and decarburization annealing, final finish annealing, and final coating are performed to obtain a product.

Immediately before decarburization annealing, heat treatment is performed at a heating rate of 100 ° C./s or higher to a temperature of 800 ° C. or higher. When the heating rate is slower than 100 ° _C./s , a low value of W _19/50 / W _17/50 cannot be obtained. Even when the heating temperature is lower than 800 ° C., a low value of W _19/50 / W _17/50 cannot be obtained. The rapid heat treatment may be incorporated in the heating stage of the decarburization annealing, and this is desirable because there are fewer steps.
The product is subjected to magnetic domain control, that is, laser irradiation, plasma irradiation, tooth profile roll and groove processing by etching. Alternatively, magnetic domain control is performed by performing groove processing by a tooth profile roll or etching in an intermediate process such as cold rolled sheet, decarburized annealed sheet, high temperature annealed sheet or the like.

Example 1
Continuous casting of molten steel, slab heating, hot rolling, C: 0.071%, Si: 3.22%, Mn: 0.088%, S: 0.028%, Sol. A 2.3 mm thick hot coil containing Al: 0.022%, N: 0.0091%, Sn: 0.12%, Cu: 0.07% was obtained. Then, after soaking at 1100 ° C. × 10 seconds + 950 ° C. × 60 seconds, hot-rolled sheet annealing was performed to rapidly cool, and the steel sheet was strongly cold-rolled to 0.22 mm to obtain a product sheet thickness.
Thereafter, when the obtained cold-rolled sheet is decarburized and annealed, the heating stage is heated to 850 ° C. at various heating rates, and then decarburized and annealed in wet hydrogen at 850 ° C., followed by application of an annealing separator. Thereafter, it was kept at 1200 ° C. for 20 hours in a hydrogen stream and subjected to final finish annealing, and a coating solution was applied to obtain a product.

The average deviation angle of the {110} <001> orientation is 3 degrees, and the components in the steel of the product are C: 0.002%, Si: 3.18%, Mn: 0.080%, S: 0.00. 001%, Sol. Al: 0.012%, N: 0.0010%, Sn: 0.12%, Cu: 0.07%. The magnetic domain was controlled by laser irradiation under the conditions of an irradiation row interval of 6.5 mm, an irradiation point interval of 0.5 mm, and an irradiation energy of 1.0 mJ / mm ² . Table 1 shows the relationship between the heating rate of decarburization annealing and magnetic properties. From this, it can be seen that the inventive example is superior in high magnetic field iron loss compared to the comparative example.

(Example 2)
Molten steel is continuously cast, slab heated, hot rolled, C: 0.070%, Si: 3.28%, Mn: 0.078%, S: 0.024%, Sol. A 2.0 mm thick hot coil containing Al: 0.021%, N: 0.0089%, Sn: 0.12%, Cu: 0.07% was obtained. Then, after soaking at 1100 ° C. × 10 seconds + 950 ° C. × 60 seconds, hot-rolled sheet annealing was performed to rapidly cool to 0.22 mm to obtain a product sheet thickness.
Thereafter, when the obtained cold-rolled sheet is decarburized and annealed, the heating stage is heated to various temperatures at a heating rate of 300 ° C./s, and then decarburized and annealed in wet hydrogen at 850 ° C., followed by annealing separation. After the agent was applied, it was held at 1200 ° C. for 20 hours in a hydrogen stream and subjected to final finish annealing, and a coating solution was applied to obtain a product.

The average deviation angle of the {110} <001> orientation is 3 degrees, and the components in the steel of the product are C: 0.002%, Si: 3.17%, Mn: 0.070%, S: 0.00. 001%, Sol. Al: 0.009%, N: 0.0009%, Sn: 0.12%, Cu: 0.07%. The magnetic domain was controlled by laser irradiation under the conditions of an irradiation row interval of 6.5 mm, an irradiation point interval of 0.5 mm, and an irradiation energy of 1.0 mJ / mm ² . Table 2 shows the relationship between the temperature reached in the heating stage and the magnetic characteristics. From this, it can be seen that the inventive example is superior in high magnetic field iron loss compared to the comparative example.

(Example 3)
The molten steel was directly cast on a steel strip, C: 0.078%, Si: 3.30%, Mn: 0.078%, S: 0.022%, Sol. A coil having a thickness of 2.3 mm containing Al: 0.032%, N: 0.0078%, Sn: 0.15%, and Cu: 0.07% was obtained. Then, after soaking at 1100 ° C. × 10 seconds + 950 ° C. × 60 seconds, hot-rolled sheet annealing was performed to rapidly cool, and the steel sheet was strongly cold-rolled to 0.22 mm to obtain a product sheet thickness.
Thereafter, when the obtained cold-rolled sheet is decarburized and annealed, the heating step is heated to 850 ° C. at 400 ° C./s, and then decarburized and annealed in wet hydrogen at 850 ° C., followed by applying an annealing separator. Thereafter, it was kept at 1200 ° C. for 20 hours in a hydrogen stream and subjected to final finish annealing, and a coating solution was applied to obtain a product.

The average deviation angle of the {110} <001> orientation is 3 degrees, and the components in the steel of the product are C: 0.002%, Si: 3.18%, Mn: 0.070%, S: 0.00. 001%, Sol. Al: 0.012%, N: 0.0010%, Sn: 0.15%, Cu: 0.07%. Some samples were subjected to groove processing by etching to change the average of 180-degree magnetic domain width. The groove processing conditions are a groove interval of 5 mm, a groove width of 150 μm, and a groove depth of 30 μm. Table 3 shows the average 180 ° magnetic domain width and W _17/50 , W _19/50 , and W _19/50 / W _17/50 at this time. From this, it can be seen that the example of the present invention is excellent in high magnetic field iron loss.

Example 4
Continuous casting of molten steel, slab heating, hot rolling, C: 0.078%, Si: 3.30%, Mn: 0.078%, S: 0.022%, Sol. Various hot plate coils containing Al: 0.032%, N: 0.0078%, Sn: 0.15%, Cu: 0.07% were prepared. Then, after soaking at 1100 ° C. × 10 seconds + 950 ° C. × 60 seconds, hot-rolled sheet annealing was performed to rapidly cool, and the steel sheet was strongly cold-rolled to 0.22 mm to obtain a product sheet thickness.
Thereafter, when the obtained cold-rolled sheet is decarburized and annealed, the heating step is heated to 850 ° C. at 400 ° C./s, and then decarburized and annealed in wet hydrogen at 850 ° C., followed by applying an annealing separator. Thereafter, it was kept at 1200 ° C. for 20 hours in a hydrogen stream and subjected to final finish annealing, and a coating solution was applied to obtain a product.

The components in the steel of the product are C: 0.002%, Si: 3.20%, Mn: 0.068%, S: 0.001%, Sol. Al: 0.011%, N: 0.0010%, Sn: 0.15%, Cu: 0.07%. The magnetic domain was controlled by laser irradiation under the conditions of an irradiation row interval of 6.5 mm, an irradiation point interval of 0.5 mm, and an irradiation energy of 1.0 mJ / mm ² . The average of the 180-degree magnetic domain width was 0.23 to 0.26 mm.
Table 4 shows the _{cold rolling ratio} , average deviation angle of {110} <001> orientation, and W _17/50 , W _19/50 , and W _19/50 / W _17/50 . From this, it can be seen that the example of the present invention is excellent in high magnetic field iron loss.

(Example 5)
Continuous casting of molten steel, slab heating, hot rolling, C: 0.075%, Si: 3.31%, Mn: 0.075%, S: 0.014%, Se: 0.014%, Sol. A slab containing Al: 0.027%, N: 0.0089%, Sb: 0.15%, Mo: 0.03% is continuously cast, slab heated, hot-rolled, and 2.7 mm thick. A hot-rolled sheet was obtained. Hot-rolled sheet annealing was performed at 1000 ° C. for 2 minutes and cold-rolled to 1.60 mm, and precipitation annealing was soaked at 1100 ° C. for 2 minutes and then rapidly cooled to 0.22 mm.
Thereafter, when the obtained cold-rolled sheet is decarburized and annealed, the heating stage is heated to various temperatures at a heating rate of 300 ° C./s, and then decarburized and annealed in wet hydrogen at 850 ° C., followed by annealing separation. After the agent was applied, it was held at 1200 ° C. for 20 hours in a hydrogen stream and subjected to final finish annealing, and a coating solution was applied to obtain a product.

The average deviation angle of the {110} <001> orientation is 4 degrees, and the components in the steel of the product are C: 0.003%, Si: 3.21%, Mn: 0.070%, S: 0 .001%, Se: 0.001%, Sol. Al: 0.010%, N: 0.0015%, Sb: 0.15%, Mo: 0.03%.
During the manufacturing process, some samples were subjected to groove processing by etching on a cold-rolled plate under the conditions that the groove interval was 3 mm, the groove width was 150 μm, and the groove depth was 20 μm, and magnetic domain control was performed. Table 5 shows the magnetic characteristics at this time. From this, it can be seen that the present invention example is superior in high magnetic field iron loss as compared with the comparative example.

Claims (2)

% By weight
C: 0.005% or less,
Si: 2.0-7.0%,
Mn: 0.2% or less,
Al: 0.065% or less,
N: 0.005% or less,
Total of one or two of S and Se: 0.005% or less, the balance is composed of Fe and inevitable impurities, and the crystal orientation of the steel sheet is relative to the ideal orientation of {110} <001> W _19/50 / W _17/50 : 1.84 or less, characterized in that the average value is a deviation of orientation of 5 degrees or less, and the average 180-degree magnetic domain width of the steel sheet is 0.26 mm or less. And W _19/50 : 1.36 or less unidirectional electrical steel sheet. It further contains 0.003 to 0.3% of one or more of Sb, Sn, Cu, Mo, Ge, B, Te, As, Cr, and Bi, respectively, by weight%. Item 1. A unidirectional electrical steel sheet according to item 1 .

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