JPH04341519A - Production of grain-oriented silicon steel sheet having superior iron loss - Google Patents

Abstract

PURPOSE:To produce a grain-oriented silicon steel sheet excellent in iron loss characteristics by subjecting a grain-oriented silicon steel slab in which MnSe is used as a principal inhibitor to hot rolling and cold rolling to the final sheet thickness and then performing decarburizing annealing under specific conditions, secondary recrystallization annealing, and purification annealing. CONSTITUTION:A slab of a silicon steel having a composition containing, by weight, 0.02-0.08% C, 2.5-4.0% Si, 0.02-0.15% Mn, 0.010-0.060% Se, 0.01-0.20% Sb, and 0.02-0.30% Cu is hot-rolled and is then cold-rolled once or cold-rolled twice or more while process- annealed between the cold rolling stages, by which a cold rolled sheet of final sheet thickness is prepared. This sheet is heated up to 850-1000 deg.C at >=10 deg.C/sec temp. rise rate, held at a temp. in the above temp. range in a nonoxidizing atmosphere of <=15 deg.C dew point for 5-60sec, and successively held in a wet-hydrogen atmosphere of 780-850 deg.C for 30sec-5min to undergo decarburizing annealing. Subsequently, a separation agent at annealing composed essentially of MgO is applied to the surface of the steel sheet and secondary recrystallization annealing and purification annealing are done. By this method, the grain-oriented silicon steel sheet in which MnSe is used as a principal inhibitor and which has superior iron loss can be produced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing grain-oriented silicon steel sheets with good core loss and suitable for use as cores of transformers and other electrical equipment.

0002

[Prior Art] Conventionally, methods for reducing iron loss in grain-oriented silicon steel sheets include 1) increasing Si content, 2) reducing product thickness, and 3) making secondary recrystallized grains finer. , 4) reducing the impurity content, and 5) aligning the secondary recrystallized grains in the (110) [001] orientation (referred to as the Goss orientation) to a higher degree. Among these methods, the method of increasing the Si content is not suitable as an industrial production method because if the Si amount exceeds 4 wt% (hereinafter simply expressed as %), cold rollability is significantly impaired.

On the other hand, various methods have been disclosed for reducing the thickness of the product board. For example, regarding grain-oriented silicon steel sheets using AlN as an inhibitor,
Publication No. 8-217630 and JP-A-59-12672
In Publication No. 2, Sn and Cu are added to the components to achieve a 0.
A method for obtaining a product with a plate thickness of 15 to 0.25 mm is disclosed. Regarding grain-oriented silicon steel sheets with MnSe and MnS as inhibitors, Japanese Patent Application Laid-Open No. 62-16782
0, JP-A No. 62-167821, and JP-A No. 62-167822, 0.15 to 0.
A method for obtaining a product with a plate thickness of 25 mm and an average grain size in the range of 1 to 6 mm after secondary recrystallization is disclosed.

However, when Sn and Cu are added to grain-oriented silicon steel sheets with AlN as the main inhibitor,
JP-A-58-217630 and JP-A No. 59-126
Although the method disclosed in Japanese Patent No. 722 can obtain a relatively high value of magnetic flux density, it cannot be said to be sufficient in improving iron loss. For example, according to Table 5 of JP-A-59-126722, the iron loss is 0.85 to 0 at W17/50.
．． It is 90W/kg, which is not a satisfactory value. Moreover,
For grain-oriented silicon steel sheets with AlN as the main inhibitor, the appropriate final cold rolling reduction ratio exceeds 80%, but in this case, if the sheet thickness becomes 0.23 mm or less, secondary recrystallization becomes unstable and a good The disadvantage was that the probability of obtaining a product with iron loss sharply decreased.

On the other hand, Japanese Unexamined Patent Application Publication Nos. 167820/1982 and 1983/1982 aimed at making grain-oriented silicon steel sheets thinner and finer grains using MnSe and MnS as inhibitors.
The methods disclosed in JP 167821 and JP 62-167822 have a lower magnetic flux density than grain-oriented silicon steel in which AlN is the main inhibitor, and therefore are inferior in terms of hysteresis loss. However, it is advantageous in terms of grain refinement, and as a result, the total iron loss is 0.83 to 0.88 W/ for W17/50, according to the results shown in Table 2 of JP-A-62-167820. k
g, which is comparable to the case where AlN is the main inhibitor. However, it is difficult to say that the level of iron loss value is fully satisfactory. However, in grain-oriented silicon steel with MnSe and MnS as the main inhibitors, the optimum cold rolling reduction is 55 to 88%, so the main inhibitor is A.
Compared to lN grain-oriented silicon steel, the plate thickness is 0.23 mm.
Secondary recrystallization is also extremely stable in the following cases.

[0006]

[Problems to be Solved by the Invention] This invention is directed to the use of MnSe.
By taking advantage of the stability of secondary recrystallization, which is the advantage of grain-oriented silicon steel, which has a main inhibitor of The purpose of this study is to propose an advantageous manufacturing method for grain-oriented silicon steel sheets that can achieve low iron loss.

[0007]

[Means for solving the problem] That is, this invention
:0.02~0.08%, Si:2.5~4.0%
, Mn: 0.02-0.15%, Se: 0.010-
0.060%, Sb: 0.01-0.20% and C
A silicon steel slab containing u: 0.02 to 0.30% and having a composition of substantially Fe with the remainder being hot rolled and then cold rolled once or twice or more including intermediate annealing. After achieving the final thickness, decarburization annealing is performed, and then MgO is applied to the surface of the steel sheet.
A method for producing a grain-oriented silicon steel sheet comprising a series of steps of applying an annealing separator containing as a main component and then performing secondary recrystallization annealing and purification annealing, which is characterized by the following features. 1. (a) Decarburization annealing is heated to a temperature of 850°C to 1000°C at a temperature increase rate of 10°C/s or more, and held in a non-oxidizing atmosphere with a dew point of 15°C or less in this temperature range for 5 to 60 seconds. After that, the method is held in a wet hydrogen atmosphere at 780 to 850°C for 30 seconds to 5 minutes.
It is.

2. (b) Final finished plate thickness from 0.12 to
(c) Secondary recrystallization annealing,
The temperature was raised at a rate of 15°C/h or more to a constant temperature between 840 and 900°C, maintained at that temperature for 30 minutes to 5 hours in a mixed atmosphere of Ar and N2, and then raised for 20 minutes from that temperature.
A method for producing a grain-oriented silicon steel sheet with good iron loss (second invention), which comprises holding at a constant temperature of ~50° C. for 20 hours or more.

3. (b) Final finished plate thickness from 0.12 to
(d) in the annealing separator;
A directional structure with good iron loss comprising containing 1 to 50 parts by weight of a spinel-type composite oxide containing aluminum in terms of Al2O3 and 1 to 20 parts by weight in terms of TiO2 of a Ti compound to 100 parts by weight of MgO. This is a method for manufacturing a raw steel sheet (third invention).

4. (a) Decarburization annealing, heating rate: 10
Heating to a temperature of 850°C to 1000°C at ℃/s or more,
After holding in a non-oxidizing atmosphere with a dew point of 15°C or less in this temperature range for 5 to 60 seconds, the treatment is held in a wet hydrogen atmosphere of 780 to 850°C for 30 seconds to 5 minutes, (b) Final Finished plate thickness 0.12-0.23mm
(c) secondary recrystallization annealing, 840-9
The temperature is raised at a rate of 15°C/h or more to a constant temperature between 00°C and kept at that temperature for 30 minutes to 5 hours in a mixed atmosphere of Ar and N2, and then raised to a constant temperature 20 to 50°C lower than that temperature. This is a method for manufacturing a grain-oriented silicon steel sheet with good core loss (fourth invention), comprising: holding the temperature at a temperature for 20 hours or more.

5. (a) Decarburization annealing, heating rate: 10
Heating to a temperature of 850°C to 1000°C at ℃/s or more,
After holding in a non-oxidizing atmosphere with a dew point of 15°C or less in this temperature range for 5 to 60 seconds, the treatment is held in a wet hydrogen atmosphere of 780 to 850°C for 30 seconds to 5 minutes, (b) Final Finished plate thickness 0.12-0.23mm
(d) MgO 10 in the annealing separator;
Oriented silicon with good iron loss, which contains 1 to 50 parts by weight of a spinel-type composite oxide containing aluminum in terms of Al2O3 and 1 to 20 parts by weight of a Ti compound in terms of TiO2. This is a method for manufacturing a steel plate (fifth invention).

6. (a) Decarburization annealing, heating rate: 10
Heating to a temperature of 850°C to 1000°C at ℃/s or more,
After holding in a non-oxidizing atmosphere with a dew point of 15°C or less in this temperature range for 5 to 60 seconds, the treatment is held in a wet hydrogen atmosphere of 780 to 850°C for 30 seconds to 5 minutes, (b) Final Finished plate thickness 0.12-0.23mm
(c) 'Secondary recrystallization annealing, 840~
A process in which the temperature is raised to a constant temperature between 900 °C at a rate of 15 °C/h or more, held at that temperature for 30 minutes to 5 hours, and then held at a constant temperature 20 to 50 °C lower than that temperature for 20 hours or more. (d) Mg in the annealing separator;
For 100 parts by weight of O, 1 to 50 parts by weight of spinel-type composite oxide containing aluminum in terms of Al2O3 and T
This is a method for manufacturing a grain-oriented silicon steel sheet with good core loss (sixth invention), which comprises containing 1 to 20 parts by weight of i compound in terms of TiO2.

[0013] Furthermore, the present invention provides the above-mentioned first, second, third, fourth, fifth or sixth invention, wherein the composition of the silicon steel slab is 7. C: 0.02-0.08%, Si: 2.5-4.
0%, Mn: 0.02-0.15%, Se: 0.01
0 to 0.060%, Sb: 0.01 to 0.20% and Cu: 0.02 to 0.30%, and Mo: 0
．． 005 to 0.05%, and the balance is essentially Fe, and has good iron loss (
7th invention).

8. C: 0.02-0.08%, Si: 2
．． 5 to 4.0%, Mn: 0.02 to 0.15%, S
e: 0.010 to 0.060%, Sb: 0.01 to
0.20% and Cu: 0.02 to 0.30%,
and Sn: 0.02 to 0.30 wt% and Ge: 0.
005 to 0.50 wt%, and the remainder is substantially composed of Fe (eighth invention).

9. C: 0.02-0.08%, Si: 2
．． 5 to 4.0%, Mn: 0.02 to 0.15%, S
e: 0.010 to 0.060%, Sb: 0.01 to
0.20% and Cu: 0.02 to 0.30%,
and Mo: 0.005 to 0.05% and Sn: 0
．． 02-0.30wt% and Ge: 0.005-0
．． This is a method for producing a grain-oriented silicon steel sheet with good iron loss, containing at least one selected from 50 wt%, with the remainder being substantially Fe.

[0016] This invention will be specifically explained below. Now, one of the problems with grain-oriented silicon steel sheets in which MnSe is the main inhibitor is that the magnetic flux density is low, as mentioned above. The main reason for this is considered to be insufficient suppressing power of MnSe as an inhibitor, and therefore, in the present invention, Cu is included in the steel in order to reinforce the suppressing force.

[0017] A method of incorporating Cu into grain-oriented silicon steel using MnSe and MnS as main inhibitors has already been disclosed in JP-A-54-32412 and JP-A-58-23.
No. 40 and Japanese Patent Application Laid-open No. 159531/1984, but these do not mention decarburization annealing, nor do they give any consideration to thinning the plate thickness or refining crystal grains. Moreover, the magnetic properties were not satisfactory.

[0018] Decarburization of grain-oriented silicon steel with MnSe and MnS as the main inhibitors is performed by annealing in a decarburizing atmosphere at approximately 800 to 850°C, as a process that combines the formation of a base film and decarburization. I was worried. Then, JP-A-1973-
In Publication No. 78733, 530-7 in the previous stage of decarburization annealing.
After holding at 00℃ for 30 seconds to 30 minutes, 740-880
The technique has been improved to one that can be carried out at ℃. Furthermore, JP-A-60-
121222, the temperature range from 400 to 750 °C is rapidly heated at a heating rate of 10 °C/s or more, and 780
P(H2O) /P(H2) in the temperature range ~820 °C
is 0.4 to 0.7 for 50 seconds or more for 10 minutes, then
P(H2O) in the temperature range of 830-870 °C
/P(H2) ranges from 0.08 to 0.4 from 10 seconds to 5
A technique for reducing the number of minutes is also disclosed. These techniques have the problem of insufficient improvement in magnetic properties, particularly low magnetic flux density.

[0019] Herein, the inventors used M as an inhibitor.
When we carefully reexamined the decarburization annealing of a grain-oriented silicon steel sheet containing Cu in nSe, we obtained the following new knowledge and completed the first invention. below,
The experimental results that led to the first invention will be explained.

Now, the inventors found that C: 0.043%, S
i: 3.39%, Mn: 0.082%, Se: 0.0
19%, Sb: 0.028% and Cu: 0.12
Steel A containing %, C: 0.040%, Si: 3.30%
%, Mn: 0.076%, Se: 0.020%, and Sb: 0.026%. After heating at 1350°C for 30 minutes,
It was hot rolled to m. After further hot-rolled plate annealing at 1000°C for 30 seconds and cold rolling to an intermediate plate thickness of 0.52 mm,
Intermediate annealing was performed at 950°C for 90 seconds, followed by 0.2
Cold rolling was performed to a thickness of 0 mm. In this decarburization annealing, the first half was heated at a rate of 20°C/s to 950°C for 30 seconds in a N2 atmosphere with a dew point of 0°C, and the second half was heated at 820°C for 90 seconds in a H2 atmosphere with a dew point of 60°C. How to do it (I
), and the temperature was raised at 18°C/s to 820°C, 120°C.
Two methods were used: method (II) in which the test was carried out in an H2 atmosphere with a dew point of 60° C. for 2 seconds; Then apply MgO 84
After being kept at 0°C for 50 hours, it was kept in H2 at 1200°C. FIG. 1 shows the results of an investigation of the magnetic properties of the product board thus obtained.

As is clear from the figure, the iron loss is the best when steel ingot A containing Cu is used and decarburization annealing is performed under the conditions (I). On the other hand, in steel ingot B that does not contain Cu in the material, when decarburization annealing is performed under the conditions of decarburization annealing (I), decarburization annealing (II), which is a normal method, is performed.
Compared to the above conditions, the iron loss actually worsened. Also, for steel ingot A, decarburization annealing conditions (II
), it is clear that good iron loss cannot be obtained only by adding Cu to the material.

The reason why the magnetic properties are improved by the above treatment is estimated as follows. That is, in decarburization annealing, two different phenomena, decarburization and primary recrystallization, are conventionally realized at the same time. By the way, the decarburization reaction occurs when carbon in the steel reacts with water vapor in the atmosphere on the surface of the steel sheet, producing CO.
The process progresses as follows. The temperature range suitable for decarburization is 780°C to 850°C; if the temperature is lower than this, the decarburization reaction will slow down and decarburization will not proceed. On the other hand, if the temperature is high, the atmosphere is closed off by the film formed during annealing, and the decarburization reaction does not proceed. Therefore, the decarburization annealing temperature was set at 780°C to 850°C.

[0023] Goss-oriented grains, which serve as nuclei for secondary recrystallization of grain-oriented silicon steel, are present in the recrystallized structure formed during this decarburization annealing. In order to obtain good magnetic properties, it is necessary that a large number of Goss-oriented grains exist in the recrystallized structure. In an experiment using the above-mentioned steel ingot A, the inventors found that 0.20
Using a cold-rolled plate with a final plate thickness of mm, the heating rate and soaking temperature during decarburization annealing were varied to correspond to the presence strength of Goss-oriented grains in the texture formed after annealing (11
0) Surface strength was investigated by X-ray diffraction. Figure 2 shows the relationship between the heating rate and (110) strength, and Figure 3 shows the relationship between soaking temperature and (110) surface strength.

As is clear from FIGS. 2 and 3, (110
) The surface strength becomes stronger as the heating rate is faster and the soaking temperature is higher. Therefore, in the first invention, in decarburization annealing, the heating rate in the first half is set at 10°C/s or more,
In addition, the soaking temperature was set at 850 to 1000°C, but annealing under such conditions resulted in secondary annealing compared to conventional annealing at 780 to 850°C, which aims to completely decarburize. The presence of Goss-oriented grains, which serve as nuclei for recrystallization, increases significantly.

Further, in the first half of the decarburization annealing of the first invention, it is necessary to make the annealing atmosphere a non-oxidizing atmosphere. This is to effectively suppress the formation of an oxide film that would impede decarburization in the latter half.

In addition to the above-mentioned texture, factors that affect secondary recrystallization include the presence of an inhibitor that suppresses the growth of grains other than Goss-oriented grains. If MnSe is simply used as an inhibitor, in the first half of the decarburization annealing of this invention, in the temperature range of 850 to 1000°C, which is advantageous for the texture, Ostwald growth of precipitates progresses, and the inhibitor's suppressing power decreases. It is undesirable to lose good magnetic properties.

[0027] In the present invention, prevention of such a decrease in the inhibitory power of the inhibitor was realized by adding Cu to the steel. In other words, like Mn, Cu in steel combines with Se to form Cu2-XSe.
Se is more finely dispersed than MnSe after hot rolling, and as an inhibitor it can obtain a stronger suppressive force than MnSe alone. In this way, the inhibitor's reinforcing effect achieved by adding Cu to steel increases the number of Goss-oriented grains in the primary recrystallized structure850
It is considered that the suppressing force is not lost even by recrystallization annealing at ~1000°C. It is thought that in the next step, the final annealing step, the increased Goss grains are guided to secondary recrystallization, thereby producing a product with low core loss and high magnetic flux density.

As described above, the first invention provides MnSe
A grain-oriented silicon steel sheet with Cu as the main inhibitor was used as the material, and in the first half of the decarburization annealing, recrystallization annealing was performed for the purpose of increasing Goss-oriented grains, and in the second half, normal By performing annealing for the purpose of decarburization, a good texture is obtained, complete decarburization is possible, and good magnetic properties are obtained.

Next, the second invention will be explained. The second invention is based on a thorough reexamination of the finish annealing of a thin grain-oriented silicon steel sheet with a final thickness of 0.23 mm or less, in which MnSe contains Cu as an inhibitor, and the following new findings have been made. It has been completed.

That is, C is added to MnSe as an inhibitor.
During secondary recrystallization annealing of grain-oriented silicon steel sheets containing u, the temperature is raised to a constant temperature between 840 and 900 °C at a rate of 15 °C/h or more, and Ar is heated at that temperature for 30 minutes to 5 hours. After being maintained in a mixed atmosphere of N2, the temperature is lowered by 20
A grain-oriented silicon steel sheet with good iron loss can be obtained by maintaining the temperature at a constant temperature lower by ~50° C. for 20 hours or more, preferably about 50 hours.

The reason why iron loss is advantageously improved by following the above steps is considered to be as follows. As mentioned above, Cu in steel combines with Se like Mn to form Cu
2-xSe is formed. The actual precipitate is a composite of MnSe and Cu2-xSe. As a result, the precipitation behavior changes, and the inhibitor Mn
It was found that unlike the case of Se alone, the amount of precipitation increases at temperatures below 900°C. The inventors focused on this point and found that when the temperature was maintained at a constant temperature within the temperature range (840 to 900 °C) in which Cu2-xSe precipitates at the initial stage of secondary recrystallization annealing, the amount of Cu2-xSe precipitated increased. It turns out that it does. It is believed that this increase in the amount of precipitation strengthens the inhibitor suppressing power and increases the magnetic flux density, which in turn maximizes the effects of thinner plate thickness and finer grains, resulting in lower iron loss. It will be done.

[0032] Also, the magnetic flux density at the initial stage of secondary recrystallization annealing is
The atmosphere during holding between 840 and 900°C was set to Ar and N2.
It was also newly discovered that the temperature rises further in a mixed atmosphere. Although the reason is not clear, C
If the atmosphere is a total N2 atmosphere when u is contained, the trace component Al becomes AlN, and Cu2-xSe
It has been found that the inhibitor is altered in combination with Ar, and therefore, it is thought that the magnetic flux density can be further improved by mixing Ar in order to eliminate its adverse effects.

As described above, the second invention provides MnSe
This is a method of obtaining low iron loss by effectively utilizing the inhibitor precipitation behavior newly discovered by the inventors, using grain-oriented silicon steel containing Cu as the main inhibitor. .

Next, the third invention will be explained. Now, the third invention was completed as a result of thorough re-examination of the annealing separator, independent of the second invention, and the new knowledge described below was obtained.

That is, during the final finish annealing of a grain-oriented silicon steel sheet containing Cu in MnSe as an inhibitor, a spinel type composite oxide containing aluminum per 100 parts by weight of MgO is added to the MgO annealing separator in terms of Al2O3. 1 to 50 parts by weight and Ti compound
By containing 1 to 20 parts by weight in terms of O2, iron loss could be further improved.

The reason why the iron loss is improved by the above treatment is considered to be as follows. When the plate thickness is thin, particularly when it is less than 0.23 mm, secondary recrystallization becomes unstable depending on the finish annealing conditions, and the magnetic properties vary greatly. Here, the actual finish annealing is performed by box annealing of each coil. Now, prior to final annealing, MgO is applied, and normally MgO is forcibly mixed with water to form a slurry and then applied to the surface of the steel sheet. A few percent of MgO in slurry form changes to Mg(OH)2,
This Mg(OH)2 decomposes at 400-500°C and releases H2O. This released H2O oxidizes the surface of the steel sheet and promotes the decomposition of the inhibitor on the surface layer. Such surface oxidation is harmful to obtaining good magnetic properties. In particular, in box annealing of individual coils, the flowability between the coil layers is extremely poor and the coil is exposed to an oxidizing atmosphere generated by H2O released from Mg(OH)2 for a long time, resulting in severe surface oxidation and deterioration of properties. do. Moreover, when the plate thickness is thin (0.23 mm or less), the influence of surface oxidation behavior is large, so such deterioration is particularly significant.

In this regard, the inventors have solved the problem caused by the interlayer atmosphere of the coil by including Cu in the material and adding a spinel type composite oxide containing aluminum and a Ti compound to the annealing separator. We have found that deterioration of characteristics can be effectively prevented. The reason is considered to be as follows. That is, (1) When Cu is contained in steel, the oxidation reaction on the surface is suppressed, and MnSe, Cu2-
The decomposition of inhibitors such as xSe is suppressed (2
) The inclusion of TiO2 in the annealing separator forms a strong forsterite film, and (3) the intrusion of Ti into the steel, which is harmful to iron loss, causes spinel-type composite oxides containing aluminum to form. It is thought that this is due to the combined effect of the above three things, which can be suppressed by adding.

In other words, the surface oxidation of the steel sheet is suppressed by the presence of Cu dissolved in the steel, and the inhibitor function effectively acts to obtain an excellent secondary recrystallized structure, but when the thickness of the steel sheet is small, In this case, the following phenomenon becomes noticeable and becomes a problem. The forsterite film on the surface of the steel sheet imparts tension to the surface of the steel sheet and has the effect of reducing iron loss, but if the interlayer atmosphere of the steel sheet is highly oxidizing during secondary recrystallization annealing, the properties of the formed film may deteriorate. It deteriorates and the tension effect decreases. If the tension effect decreases with the reduction of the steel plate thickness,
Since the amount of deterioration in iron loss increases, this becomes a problem that cannot be ignored with thin grain-oriented silicon steel sheets. It has been known that adding a Ti compound to an annealing separator is effective in improving the uniformity and adhesion of a film, but the inventors
It has been found that this has the effect of increasing the tension effect and improving the iron loss of thin grain-oriented silicon steel sheets containing Cu and Sb. However, it has been found that when a Ti compound is added alone to the annealing separator, Ti invades the steel during final annealing, and the iron loss deteriorates. Therefore, in the third invention, Ti
In order to suppress the penetration of aluminum into the steel, a spinel-type composite oxide containing aluminum was also added to the annealing separator, thereby reducing iron loss by effectively applying tension. .

A further advantage of the third invention is that it does not require complicated atmosphere control using Ar and N2 in secondary recrystallization annealing as in the second invention. The reason for this is
This is because the action of aluminum in the alumina spinel added to the annealing separator suppresses nitrogen from entering the steel. Therefore, even if the atmosphere is not controlled, there will be no problem such as Al, which is a trace component in the steel, turning into AlN and changing the quality of the inhibitor, Cu2-x Se.

As described above, the third invention provides MnSe
By using a grain-oriented silicon steel sheet with Cu as the main inhibitor and adding a spinel-type composite oxide containing aluminum and a Ti compound to the annealing separator, the interlayer atmosphere of the coil is Low iron loss is obtained by effectively utilizing the new fact that the adverse effects of oxidation can be eliminated and the inhibitor's deterioration inhibiting effect described above.

[0041]

[Operation] In this invention, the reason why the component composition of the material is limited to the above range is as follows. C: 0.02 to 0.08% C is an element useful for uniformly refining the structure and developing Goss orientation during hot rolling and cold rolling, but if it is less than 0.02%, it may cause secondary regeneration. If it exceeds 0.08%, it becomes difficult to decarburize, so it is limited to a range of 0.02 to 0.08%.

Si: 2.5 to 4.0% Si increases the specific resistance of the steel plate and effectively contributes to reducing iron loss.
If it is less than 2.5%, good iron loss cannot be obtained, while if it exceeds 4.0%, cold rollability will be significantly deteriorated.
It was limited to a range of 4.0%.

Mn: 0.02-0.15%, Se: 0.
010 to 0.060% Mn and Se are components for forming MnSe. First, Mn must be at least 0.02% in order to function as an inhibitor.
On the other hand, if it exceeds 0.15%, the solid solution temperature of MnSe becomes high and causes deterioration of the magnetic properties of solid solution at normal slab heating temperatures, so it is in the range of 0.02 to 0.15%. And so. Next, if Se exceeds 0.060%, it will be difficult to purify by purification annealing, while if it is less than 0.010%, the inhibitor amount will be insufficient, so Se should be reduced to 0.01 to 0.06%.
It shall be contained within the range of .

Sb: 0.01 to 0.20% Sb functions as a grain boundary segregation type inhibitor, but if it is less than 0.01% it is less effective as an inhibitor;
If it exceeds 0.0%, it will have an adverse effect on decarburization and surface coating formation, so it is preferably contained in a range of 0.01 to 0.20%.

Cu: 0.02-0.30% Cu is C
It is a useful element that functions as an inhibitor by forming u2-XSe, but if it is less than 0.02%, its addition effect is poor, while if it exceeds 0.30, the toughness deteriorates, so it is 0.02 to 0. It was limited to a range of 30%.

The basic components have been explained above, but in the present invention, the following elements can also be added as appropriate. Mo: 0.005 to 0.05% Mo contributes effectively to improving surface properties, but if the content is less than 0.005%, the effect of addition is poor;
．． If it exceeds 0.05%, the decarburization performance deteriorates, so 0.005%
The content is preferably in the range of 0.05% to 0.05%.

Sn: 0.02-0.30% Sn is a useful element that refines secondary recrystallized grains and improves iron loss, but if the content is less than 0.02%, the effect of addition is poor; If it exceeds 0.30%, the decarburization property will deteriorate, so 0.02~
It is preferable to contain it in the range of 0.30%.

[0048] Ge: 0.005 to 0.50% Ge also
Like Sn, it is an element useful for refining secondary recrystallized grains and improving iron loss, but if the content is less than 0.005%, the addition effect is poor, while if it exceeds 0.50%, the toughness deteriorates. It is preferably contained in a range of 0.005 to 0.50%.

The silicon steel slab adjusted to the above-mentioned preferred composition is heated and then hot rolled at room temperature. After that, in order to stabilize the magnetic properties, 900 ~
After homogenizing annealing at a temperature of about 1050° C., cold rolling is performed once or twice or more with intermediate annealing in between to obtain the final finished plate thickness.

After the cold rolling described above, decarburization annealing is performed, and the feature of the first invention lies in this decarburization annealing. In other words, decarburization annealing is performed at a temperature increase rate of 10°C/s or more.85
After heating to a temperature range of 0 to 1000°C, holding in this temperature range for a period of 5 seconds to 60 seconds in a non-oxidizing atmosphere with a dew point of 15°C or less, and then holding in a wet hydrogen atmosphere of 780 to 850°C. do. Here, the temperature increase rate is 10℃/
If the speed is less than 10° C./s, the ratio of the Goss structure in the primary recrystallized texture will decrease and the magnetic properties will deteriorate, so the speed should be 10° C./s or more. Furthermore, if the annealing temperature in the first half is less than 850°C, the proportion of Goss structure in the primary recrystallized texture will decrease and the magnetic properties will deteriorate, while if it exceeds 1000°C, the inhibitor will become Ostwald even if Cu is added to the material. 850-1000℃, as it grows and loses its suppressive power, deteriorating its magnetic properties.
Soak at a temperature of . Furthermore, if the holding time at a temperature of 850 to 1000°C is less than 5 seconds, the formation of texture is insufficient and the magnetic properties deteriorate; on the other hand, if the holding time exceeds 60 seconds, the inhibitor will undergo Ostwald growth, lose its suppressing power, and the magnetic properties will deteriorate. Therefore, the time should be at least 5 seconds and at most 60 seconds. 850 ~100
The annealing atmosphere when maintaining the temperature at 0°C is a non-oxidizing atmosphere with a dew point of 15°C or less. Here, the non-oxidizing atmosphere refers to a neutral atmosphere such as N2 or Ar, or a reducing atmosphere such as H2. Furthermore, if the dew point exceeds 15°C, decarburization will be insufficient and the magnetic properties will deteriorate, so the dew point should be 15°C or less.

Regarding the holding temperature in the latter half of the decarburization process, 7
Even if the temperature is less than 80°C, even if it exceeds 850°C, decarburization will still be poor and the magnetic properties will deteriorate, so 780~8
The temperature shall be 50°C. The atmosphere in the second half is a wet hydrogen atmosphere to cause decarburization. The holding time at 780 to 850° C. is set to 30 seconds or more and less than 5 minutes, because if it is less than 30 seconds, decarburization will be insufficient and the magnetic properties will deteriorate, while if it exceeds 5 minutes, a good insulating film will not be formed. After decarburization annealing, a separating agent containing MgO as a main component is applied, followed by secondary recrystallization annealing at a temperature of about 850°C, followed by purification annealing at about 1200°C in an H2 atmosphere.

Next, in the second invention, the final finished plate thickness is 0.
．． If it is less than 12 mm, secondary recrystallization will be poor, while if it is 0.
If the thickness exceeds 23 mm, eddy current loss increases and good iron loss cannot be obtained, so the final finished plate thickness should be 0.12 to 0.23 m.
The range was limited to m. After the above-mentioned cold rolling, decarburization annealing is performed, then an annealing separator containing MgO 2 as a main component is applied, and after drying, secondary recrystallization annealing and purification annealing are performed.

[0053] Here, the secondary recrystallization annealing is 840 to 90
The temperature is raised at a rate of 15 °C/h or more to a constant temperature between 0 °C, maintained at that temperature for 30 minutes to 5 hours in a mixed atmosphere of Ar and N2, and then raised to a constant temperature 20 to 50 °C lower than that temperature. The treatment is to maintain the temperature for 20 hours or more. Here, the holding temperature in the initial holding treatment (primary holding treatment) of secondary recrystallization annealing was set in the range of 840 to 900°C because if the holding temperature is less than 840°C, the amount of Cu2-xSe precipitation increases sufficiently. However, if the temperature exceeds 900°C, Cu2-xS has already precipitated.
This is because precipitates such as e etc. grow too much and lose their function as an inhibitor. Also, if the temperature increase rate to a constant temperature between 840 and 900 °C is less than 15 °C/h,
During heating, precipitates such as Cu2-xSe grow and the inhibitor function is impaired, so the heating rate is 15°C.
/h or more. Furthermore, if the retention time in the primary retention treatment is less than 30 minutes, the increase in the amount of Cu2-xSe precipitated will be insufficient and the magnetic properties will not improve, while if it exceeds 5 hours, the precipitates such as Cu2-xSe will grow too much. Since the inhibitor function would be lost, the period was limited to 30 minutes to 5 hours. Note that the preferred mixing ratio of the mixed atmosphere in this primary holding treatment is Ar: about 20 to 80%.

[0054] Subsequently, a secondary retention process is performed at a temperature lower than the primary retention temperature, but in this secondary retention process, if the retention temperature difference from the primary retention process is less than 20°C, the secondary retention process with a bad orientation will occur. Secondary grains grow, leading to deterioration of magnetic flux density. On the other hand, if the retention temperature difference exceeds 50°C, the growth of secondary recrystallized grains becomes insufficient and the magnetic properties deteriorate. It shall be carried out at a temperature 20 to 50 degrees Celsius lower than that of the retention treatment. At this time, if the secondary retention time is less than 20 hours, the growth of secondary recrystallized grains will be insufficient and the magnetic properties will deteriorate, so the secondary retention time is set to 20 hours or more. Although there is no particular upper limit to this retention time, about 50 hours is industrially sufficient.

Furthermore, in the third invention, regarding the MgO-based annealing separator, a spinel-type composite oxide containing aluminum is added to 100 parts by weight of MgO in the annealing separator.
1 to 50 parts by weight calculated as Al2O3 and Ti compound to TiO
It is contained in an amount of 1 to 20 parts by weight in terms of 2. If the blending ratio of the spinel-type composite oxide containing aluminum is less than 1 part by weight (calculated as Al2O3) with respect to 100 parts by weight of MgO in the annealing separator, the effect of preventing Ti from penetrating into the steel will be insufficient; If the amount exceeds 50 parts by weight, the formation of a forsterite film will be inhibited, so the blending ratio of the spinel-type composite oxide containing aluminum should be 1 to 1 in terms of Al2O3.
The amount was 50 parts by weight. Furthermore, if the proportion of the Ti compound is less than 1 part by weight, the uniformity and adhesion of the forsterite film will deteriorate, while if it exceeds 20 parts by weight, the adhesion of the forsterite film will deteriorate. was limited to a range of 1 to 20 parts by weight.

The spinel type composite oxide containing aluminum has the chemical formula: R-Al2O4 (where R is Mn
, Mg, Zn, Fe, etc.), and when adding such oxides to the annealing separator, if the particle size is too large, the effect will decrease, so it is desirable to have an average particle size of about 2 μm. Furthermore, as a Ti compound, T
iO2, TiO, Ti2O3, Ti(OH)4
, and various Ti salts, namely CaTiO3, Sr
TiO3, MgTiO3, BaTiO3, BaT
Advantageously suitable are iO4, MnTiO3 and FeTiO3.

[0057]

【Example】

Example 1 C: 0.040%, Si: 3.35%, Mn: 0.0
70%, Se: 0.021%, Sb: 0.024
% and Cu: 0.10%, and the remainder is substantially Fe, after heating it to 1430 ° C.
A hot-rolled plate with a thickness of 2.0 mm was obtained by hot rolling. Then, after a first cold rolling to an intermediate plate thickness of 0.49 mm, the plate was intermediately annealed at 975° C. for 60 seconds, and then finished to a final plate thickness of 0.20 mm by a second cold rolling. Thereafter, decarburization annealing was performed under the conditions shown in Table 1. After that, an annealing separator made of MgO with 1.5% TiO2 added was applied, followed by secondary recrystallization annealing at 850℃ for 50 hours, followed by purification annealing in H2 at 1200℃ for 10 hours. provided. Table 1 also shows the results of investigating the magnetic properties of the product thus obtained.

[0058]

[Table 1]

Example 2 A silicon steel slab having the composition shown in Table 2 was prepared using 1425
After heating to ℃, hot rolling was performed to obtain a 1.8 mm hot rolled sheet. Next, the plate was cold-rolled for the first time to have an intermediate thickness of 0.47 mm, then subjected to intermediate annealing at 1000°C for 30 seconds, and then cold-rolled for the second time to a thickness of 0.20 mm. After that, after decarburizing annealing and heating at 20 ° C / s,
It was held in a N2 atmosphere with a dew point of -30℃ at 900℃ for 20 seconds, and then in a H2 atmosphere with a dew point of 60℃ at 820℃ for 90 seconds.
This was done by holding it for a second. Then 3% to MgO
After applying an annealing separator containing TiO2 of 8
After secondary recrystallization annealing at 50°C for 50 hours, H
Purification annealing was performed at 1,200°C for 10 hours in a vacuum chamber. Table 2 also shows the results of investigating the magnetic properties of the product thus obtained.

[0060]

[Table 2]

Example 3 C: 0.042%, Si: 3.45%, Mn: 0.0
73%, Se: 0.020%, Sb: 0.026
% and Cu: 0.12%, the remainder being substantially Fe.
A silicon steel slab having the composition was heated to 1420° C. and then hot-rolled to obtain a hot-rolled plate with a thickness of 2.0 mm. Then, after a first cold rolling to an intermediate thickness of 0.48 mm, an intermediate annealing at 1000° C. for 90 seconds was carried out, followed by a second cold rolling to a final thickness of 0.18 mm. After that, decarburization annealing was performed at 820°C for 2 minutes in wet H2, and an annealing separator containing 3.0% TiO added to MgO was applied, followed by final annealing according to the temperature pattern shown in Figure 4. . Table 3 shows the results of investigating the magnetic properties of the product thus obtained.

[0062]

[Table 3]

Example 4 C: 0.040%, Si: 3.45%, Mn: 0.0
70%, Se: 0.020%, Sb: 0.02
A silicon steel slab containing 3% Cu, 0.10% Cu, and 0.010 Mo, with the remainder essentially Fe was heated to 1420°C and then hot rolled to reduce the thickness.
A hot rolled sheet with a thickness of 1.4 to 2.4 mm was obtained. Then, the intermediate plate thickness shown in Table 4 was obtained by the first cold rolling, and then 10
After performing intermediate annealing at 00°C for 90 seconds, the plate was finished to the final plate thickness shown in Table 4 by second cold rolling. after that,
After decarburizing annealing at 820° C. for 2 minutes in wet H2, an annealing separator containing 3.0% TiO2 added to MgO was applied, and finish annealing was performed according to the pattern shown in FIG. Table 4 also shows the results of investigating the magnetic properties of the product thus obtained.

[0064]

Example 5 A silicon steel slab having the composition shown in Table 5 was prepared using 1420
After heating to ℃, hot rolling was performed to obtain a 2.0 mm hot rolled sheet. Then, after hot-rolled plate annealing at 1000°C for 1 minute, the intermediate plate thickness was made to 0.52 mm by the first cold rolling, and after intermediate annealing at 950°C for 90 seconds,
It was finished to a thickness of 0.20 mm by second cold rolling. After that, decarburization annealing was performed at 820°C for 2 minutes in a humid H2 atmosphere, and the material was then decarburized with 2% TiO2 and the remaining
An annealing separator made of MgO was applied, and then finish annealing was performed according to the pattern shown in FIG. Table 5 also shows the results of investigating the magnetic properties of the product thus obtained.

[0066]

[Table 5]

Example 6 C: 0.045%, Si: 3.40%, Mn: 0.0
71%, Se: 0.021%, Sb: 0.025
% and Cu: 0.10%, the remainder being substantially F
A silicon steel slab having the composition e was heated to 1420° C. and then hot-rolled into a hot-rolled plate having a thickness of 2.0 mm. Next, the plate was cold rolled for the first time to an intermediate thickness of 0.52 mm, then subjected to intermediate annealing at 950° C. for 90 seconds, and then cold rolled for the second time to a final thickness of 0.20 mm. After that, in a humid H2 atmosphere at 820℃,
After decarburization annealing for 2 minutes, an annealing separator having various components shown in Table 6 was applied. Magnesia spinel (MgAl2O4) was used as the spinel type composite oxide, and TiO2 was used as the Ti compound. After that, Figure 6
Finish annealing was performed according to the temperature pattern shown below. The results of the investigation on the magnetic properties of the product thus obtained and the appearance of the coating on the steel plate are also listed in Table 6.

[0068]

[Table 6]

Example 7 C: 0.041%, Si: 3.39%, Mn:
0.076%, Se: 0.020%, Sb: 0.0
25%, Cu: 0.11% and Mo: 0.010
After heating the silicon steel slab to 1420° C., the silicon steel slab was heated to 1420° C. and then hot-rolled into a hot-rolled plate having a thickness of 1.4 to 2.4 mm. Then, after the first cold rolling to the intermediate plate thickness shown in Table 7,
After intermediate annealing at 950°C for 90 seconds, the final plate thickness shown in Table 7 was obtained by a second cold rolling. Then wet H
After performing decarburization annealing at 850°C for 2 minutes in an atmosphere of After that, finish annealing was performed according to the temperature pattern shown in FIG. Table 7 also shows the results of investigating the magnetic properties of the product thus obtained.

[0070]

Example 8 A silicon steel slab having the composition shown in Table 8 was prepared using 1430
After heating to ℃, hot rolling was performed to obtain a 1.8 mm hot rolled sheet. Then, after annealing at 1000°C for 1 minute, the plate was cold rolled for the first time to an intermediate thickness of 0.50 mm.
After intermediate annealing at 975° C. for 1 minute, the final plate thickness was 0.20 mm by second cold rolling. After that, decarburization annealing was performed at 850°C for 2 minutes in a humid H2 atmosphere, and then an annealing separator containing 20 parts by weight of magnesia spinel (MgAl2O4) and 3 parts by weight of TiO2 was added to 100 parts by weight of MgO. After coating, finish annealing was performed according to the temperature pattern shown in FIG. Table 8 also shows the results of investigating the magnetic properties of the product thus obtained.

[0072]

[Table 8]

Example 9 C: 0.036%, Si: 3.33%, Mn: 0.0
68%, Se: 0.020%, Sb: 0.025
% and Cu: 0.15%, and the remainder is substantially Fe, after heating it to 1430 ° C.
A hot-rolled plate with a thickness of 2.0 mm was obtained by hot rolling. Then, after hot-rolled plate annealing at 975°C for 1 minute, the intermediate plate thickness was made to 0.50 mm by the first cold rolling, and then 100 mm
After intermediate annealing at 0°C for 1 minute, the temperature was reduced to 0 by second cold rolling.
．． Finished to a final thickness of 20mm.

[0074] After that, as decarburization annealing, temperature increase rate: 15
The temperature was increased at a rate of .degree. C./s, and the treatment was carried out under various conditions shown in Table 9. After that, an annealing separator containing MgO as the main component was applied, and then heated at a temperature increase rate of 25°C/h, secondary recrystallization annealing was performed under various conditions shown in Table 9, and then 120°C in H2
Purification annealing was performed at 0°C for 5 hours. Table 9 also shows the results of investigating the magnetic properties of the product thus obtained.

[0075]

[Table 9]

Example 10 C: 0.038%, Si: 3.35%, Mn: 0.0
68%, Se: 0.020%, Sb: 0.027
%, Cu: 0.18%, Mo: 0.012%, and the remainder is essentially Fe. After heating to 1420°C, a silicon steel slab was hot rolled to a thickness of 1.4%.
It was made into a hot rolled sheet of ~2.4 mm. Then 975℃,
After hot-rolled sheet annealing for 1 minute, the first cold rolling produced Table 1
After the intermediate plate thickness shown in Table 10 was obtained, intermediate annealing was performed at 1000° C. for 90 seconds, and the final plate thickness shown in Table 10 was obtained by a second cold rolling.

[0077] After that, decarburization annealing was performed at a temperature increase rate of 15°C/
After raising the temperature at 850°C and a dew point of 10°C for 15 seconds, it was then heated to 820°C and a dew point of 60°C.
This was done by holding the sample in an H2 atmosphere for 80 seconds. Thereafter, an annealing separator containing 2% TiO2 in MgO2 was applied, followed by final annealing according to the pattern shown in FIG. Table 10 also shows the results of investigating the magnetic properties of the product thus obtained.

[0078]

Example 11 A silicon steel slab having the composition shown in Table 11 was prepared using 143
After heating to 0° C., hot rolling was performed to obtain a hot rolled sheet having a thickness of 1.8 mm. Then, after hot-rolled sheet annealing at 1000°C for 1 minute, the sheet was cold-rolled for the first time to an intermediate thickness of 0.50 mm, then intermediately annealed at 975°C for 1 minute, and then cold-rolled for the second time to a thickness of 0.50 mm. Finished to a final thickness of 20mm.

[0080] After that, decarburization annealing was performed at a temperature increase rate of 20°C/
The test was carried out by heating at 865° C. and a dew point of 5° C. for 10 seconds, and then at 825° C. and holding a dew point of 55° C. in an H2 atmosphere for 90 seconds. Thereafter, an annealing separator containing 1.5% TiO2 in MgO2 was applied, and finish annealing was performed according to the pattern shown in FIG. Table 11 also shows the results of investigating the magnetic properties of the product thus obtained.

[0081]

[Table 11]

Example 12 C: 0.042%, Si: 3.33%, Mn: 0.0
70%, Se: 0.020%, Sb: 0.026
% and Cu: 0.21%, and the remainder is substantially Fe, after heating it to 1420 ° C.
A hot-rolled plate with a thickness of 2.0 mm was obtained by hot rolling. Then, after a first cold rolling to give an intermediate thickness of 0.50 mm, an intermediate annealing at 950° C. for 90 seconds was carried out, followed by a second cold rolling to a final thickness of 0.20 mm.

[0083] After that, as decarburization annealing, temperature increase rate: 15
The temperature was increased at a rate of °C/s, and the treatment was performed under various conditions shown in Table 12. After that, an annealing separator containing 100 parts by weight of MgO and the additives shown in Table 12 was applied, and the temperature was increased at 20°C/h.
secondary recrystallization annealing was performed under various conditions shown in Table 12, and then heated at 1200°C in H2 at 5°C.
Subjected to time purification annealing. Table 12 also shows the results of investigating the magnetic properties of the product thus obtained.

[0084]

[Table 12]

Example 13 C: 0.040%, Si: 3.34%, Mn: 0.0
70%, Se: 0.021%, Sb: 0.025
%, Cu: 0.13%, Mo: 0.013%, and the remainder is essentially Fe. After heating to 1430°C, a silicon steel slab was hot rolled to a thickness of 1.4%.
It was made into a hot rolled sheet of ~2.4 mm. Then 975℃,
After hot-rolled sheet annealing for 1 minute, the first cold rolling produced Table 1
After the intermediate plate thickness shown in Table 13 was obtained, intermediate annealing was performed at 1000° C. for 60 seconds, followed by a second cold rolling to give the final plate thickness shown in Table 13.

[0086] After that, decarburization annealing was performed at a temperature increase rate of 15°C/
After raising the temperature at 855°C and a dew point of 10°C for 15 seconds, it was then heated to 820°C and a dew point of 60°C.
This was done by holding the sample in an H2 atmosphere for 80 seconds. Thereafter, an annealing separator containing 5 parts by weight of TiO2 and 15 parts by weight of MgAl2O4 per 100 parts by weight of MgO was applied, and then finish annealing was performed according to the pattern shown in FIG. Table 13 also shows the results of investigating the magnetic properties of the product thus obtained.

[0087]

Example 14 A silicon steel slab having the composition shown in Table 14 was prepared using 143
After heating to 0° C., hot rolling was performed to obtain a hot rolled sheet having a thickness of 1.8 mm. Then, after hot-rolled plate annealing at 1000°C for 1 minute, the intermediate plate thickness was made to 0.50 mm by a first cold rolling, and after intermediate annealing at 1000°C for 1 minute, a second cold rolling was performed to give an intermediate thickness of 0.50 mm. Finished to a final thickness of 20mm.

[0089] After that, decarburization annealing was performed at a temperature increase rate of 20°C/
After raising the temperature at 865°C and a dew point of 10°C for 10 seconds, it was then heated to 820°C and a dew point of 60°C.
This was done by holding the sample in an H2 atmosphere for 90 seconds. Thereafter, an annealing separator containing 5 parts by weight of TiO2 and 15 parts by weight of MgAl2O4 per 100 parts by weight of MgO was applied, and then finish annealing was performed according to the pattern shown in FIG. Table 14 also shows the results of investigating the magnetic properties of the product thus obtained.

[0090]

[Table 14]

[0091]

[Effect of the invention] According to the first invention, M as an inhibitor
By using nSe and Cu2-XSe together, recrystallization is performed in the first half of decarburization annealing to increase Goss-oriented grains, and normal annealing is performed to decarburize the steel sheet. Formation of texture and complete decarburization can be achieved together, and thus grain-oriented silicon steel sheets with good magnetic properties can be stably obtained.

Furthermore, according to the second invention, by using MnSe and Cu2-XSe together as inhibitors and performing final finish annealing under specific conditions, a grain-oriented silicon steel sheet with even better magnetic properties can be stably produced. Obtainable.

Furthermore, according to the third invention, by using MnSe and Cu2-XSe together as inhibitors and adding a spinel type composite oxide containing aluminum and a Ti compound to the annealing separator, even better magnetic properties can be obtained. Grain-oriented silicon steel sheets can be stably obtained.

Furthermore, by combining the first invention, the second invention, and the third invention, it is possible to stably obtain a grain-oriented silicon steel sheet particularly excellent in magnetic properties.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between decarburization annealing and iron loss.

FIG. 2 is a graph showing the relationship between temperature increase rate and (110) plane strength in decarburization annealing.

FIG. 3 is a graph showing the relationship between soaking temperature and (110) plane strength in decarburization annealing.

FIG. 4 is a schematic diagram showing a finish annealing pattern of an example.

FIG. 5 is a schematic diagram showing a finish annealing pattern of an example.

FIG. 6 is a schematic diagram showing a finish annealing pattern of an example.

FIG. 7 is a schematic diagram showing a finish annealing pattern of an example.

Claims (9)

[Claims] [Claim 1] C: 0.02 to 0.08 wt%, Si
: 2.5 to 4.0 wt%, Mn: 0.02 to 0.1
5 wt%, Se: 0.010 to 0.060 wt%,
Sb: 0.01-0.20 wt% and Cu: 0.02
After hot rolling, a silicon steel slab containing ~0.30 wt% with the remainder substantially having a composition of Fe was cold rolled once or twice or more including intermediate annealing to obtain the final thickness. A method for producing a grain-oriented silicon steel sheet, which comprises a series of steps in which the steel sheet is then subjected to decarburization annealing, then an annealing separator containing MgO as a main component is applied to the surface of the steel sheet, and then secondary recrystallization annealing and purification annealing are performed. In (a) decarburization annealing, heating rate:
Heating at a rate of 10°C/s or more to a temperature of 850°C to 1000°C, holding in a non-oxidizing atmosphere with a dew point of 15°C or less within this temperature range for 5 to 60 seconds, and then heating to 780°C to 850°C.
1. A method for producing a grain-oriented silicon steel sheet with good iron loss, characterized by holding the treatment in a moist hydrogen atmosphere for 30 seconds to 5 minutes. [Claim 2] C: 0.02 to 0.08 wt%, Si
: 2.5 to 4.0 wt%, Mn: 0.02 to 0.1
5 wt%, Se: 0.010 to 0.060 wt%,
Sb: 0.01-0.20 wt% and Cu: 0.02
After hot rolling, a silicon steel slab containing ~0.30 wt% with the remainder substantially having a composition of Fe was cold rolled once or twice or more including intermediate annealing to obtain the final thickness. A method for producing a grain-oriented silicon steel sheet, which comprises a series of steps in which the steel sheet is then subjected to decarburization annealing, then an annealing separator containing MgO as a main component is applied to the surface of the steel sheet, and then secondary recrystallization annealing and purification annealing are performed. In (b) the final finished plate thickness is 0.1
(c) Secondary recrystallization annealing to a constant temperature between 840 and 900 °C at 15 °C/
A
A method for manufacturing a grain-oriented silicon steel sheet with good iron loss, characterized by holding in a mixed atmosphere of r and N2, and then holding at a constant temperature 20 to 50°C lower than that temperature for 20 hours or more. . [Claim 3] C: 0.02 to 0.08 wt%, Si
: 2.5 to 4.0 wt%, Mn: 0.02 to 0.1
5 wt%, Se: 0.010 to 0.060 wt%,
Sb: 0.01-0.20 wt% and Cu: 0.02
After hot rolling, a silicon steel slab containing ~0.30 wt% with the remainder substantially having a composition of Fe was cold rolled once or twice or more including intermediate annealing to obtain the final thickness. A method for producing a grain-oriented silicon steel sheet, which comprises a series of steps in which the steel sheet is then subjected to decarburization annealing, then an annealing separator containing MgO as a main component is applied to the surface of the steel sheet, and then secondary recrystallization annealing and purification annealing are performed. In (b) the final finished plate thickness is 0.1
(d) In the annealing separator, for 100 parts by weight of MgO, 1 to 50 parts by weight of a spinel type composite oxide containing aluminum in terms of Al2O3 and 1 part of Ti compound in terms of TiO2. A method for producing a grain-oriented silicon steel sheet with good iron loss, characterized by containing ~20 parts by weight. [Claim 4] C: 0.02 to 0.08 wt%, Si
: 2.5 to 4.0 wt%, Mn: 0.02 to 0.1
5 wt%, Se: 0.010 to 0.060 wt%,
Sb: 0.01-0.20 wt% and Cu: 0.02
After hot rolling, a silicon steel slab containing ~0.30 wt% with the remainder substantially having a composition of Fe was cold rolled once or twice or more including intermediate annealing to obtain the final thickness. A method for producing a grain-oriented silicon steel sheet, which comprises a series of steps in which the steel sheet is then subjected to decarburization annealing, then an annealing separator containing MgO as a main component is applied to the surface of the steel sheet, and then secondary recrystallization annealing and purification annealing are performed. In (a) decarburization annealing, heating rate:
Heating at a rate of 10°C/s or more to a temperature of 850°C to 1000°C, holding in a non-oxidizing atmosphere with a dew point of 15°C or less within this temperature range for 5 to 60 seconds, and then heating to 780°C to 850°C.
(b) The final finished plate thickness is 0.12 to 0.23.
(c) Secondary recrystallization annealing to 840 mm.
The temperature was raised at a rate of 15°C/h or more to a constant temperature between ~900°C, maintained at that temperature for 30 minutes to 5 hours in a mixed atmosphere of Ar and N2, and then raised by 20°C to 50°C from that temperature.
The treatment must be maintained at a constant low temperature for 20 hours or more,
A method for producing a grain-oriented silicon steel sheet with good iron loss. [Claim 5] C: 0.02 to 0.08 wt%, Si
: 2.5 to 4.0 wt%, Mn: 0.02 to 0.1
5 wt%, Se: 0.010 to 0.060 wt%,
Sb: 0.01-0.20 wt% and Cu: 0.02
After hot rolling, a silicon steel slab containing ~0.30 wt% with the remainder substantially having a composition of Fe was cold rolled once or twice or more including intermediate annealing to obtain the final thickness. A method for producing a grain-oriented silicon steel sheet, which comprises a series of steps in which the steel sheet is then subjected to decarburization annealing, then an annealing separator containing MgO as a main component is applied to the surface of the steel sheet, and then secondary recrystallization annealing and purification annealing are performed. In (a) decarburization annealing, heating rate:
Heating at a rate of 10°C/s or more to a temperature of 850°C to 1000°C, holding in a non-oxidizing atmosphere with a dew point of 15°C or less within this temperature range for 5 to 60 seconds, and then heating to 780°C to 850°C.
(b) The final finished plate thickness is 0.12 to 0.23.
(d) MgO in the annealing separator
containing 1 to 50 parts by weight of a spinel-type composite oxide containing aluminum in terms of Al2O3 and 1 to 20 parts by weight of a Ti compound in terms of TiO2 to 100 parts by weight;
A method for producing a grain-oriented silicon steel sheet with good iron loss. [Claim 6] C: 0.02 to 0.08 wt%, Si
: 2.5 to 4.0 wt%, Mn: 0.02 to 0.1
5 wt%, Se: 0.010 to 0.060 wt%,
Sb: 0.01-0.20 wt% and Cu: 0.02
After hot rolling, a silicon steel slab containing ~0.30 wt% with the remainder substantially having a composition of Fe was cold rolled once or twice or more including intermediate annealing to obtain the final thickness. A method for producing a grain-oriented silicon steel sheet, which comprises a series of steps in which the steel sheet is then subjected to decarburization annealing, then an annealing separator containing MgO as a main component is applied to the surface of the steel sheet, and then secondary recrystallization annealing and purification annealing are performed. In (a) decarburization annealing, heating rate:
Heating at a rate of 10°C/s or more to a temperature of 850°C to 1000°C, holding in a non-oxidizing atmosphere with a dew point of 15°C or less within this temperature range for 5 to 60 seconds, and then heating to 780°C to 850°C.
(b) The final finished plate thickness is 0.12 to 0.23.
(c) 'Secondary recrystallization annealing, 84
After increasing the temperature to a constant temperature between 0 and 900 °C at a rate of 15 °C/h or more and maintaining that temperature for 30 minutes to 5 hours,
(d) The annealing separator contains:
A method for improving iron loss characterized by containing 1 to 50 parts by weight of a spinel type composite oxide containing aluminum in terms of Al2O3 and 1 to 20 parts by weight in terms of TiO2 of a Ti compound with respect to 100 parts by weight of MgO. manufacturing method of silicon steel sheet. 7. Claim 1, 2, 3, 4, 5 or 6, wherein the silicon steel slab has a composition of C: 0.02 to 0.02.
0.08 wt%, Si: 2.5 to 4.0 wt%, M
n: 0.02 to 0.15 wt%, Se: 0.010 to
0.060 wt%, Sb: 0.01-0.20 wt%
and Cu: 0.02 to 0.30 wt%, and M
0.005 to 0.05 wt%, with the remainder being substantially Fe. 8. Claim 1, 2, 3, 4, 5 or 6, wherein the silicon steel slab has a composition of C: 0.02 to 0.02.
0.08 wt%, Si: 2.5 to 4.0 wt%, M
n: 0.02 to 0.15 wt%, Se: 0.010 to
0.060 wt%, Sb: 0.01-0.20 wt%
and Cu: 0.02 to 0.30 wt%, and S
n: 0.02-0.30wt% and Ge: 0.005
A method for producing a grain-oriented silicon steel sheet with good iron loss, which contains at least one selected from ~0.50 wt%, with the remainder being substantially Fe. 9. Claim 1, 2, 3, 4, 5 or 6, wherein the silicon steel slab has a composition of C: 0.02 to 0.02.
0.08 wt%, Si: 2.5 to 4.0 wt%, M
n: 0.02 to 0.15 wt%, Se: 0.010 to
0.060 wt%, Sb: 0.01-0.20 wt%
and Cu: 0.02 to 0.30 wt%, and M
o: 0.005 to 0.05 wt% and Sn: 0.
02-0.30 wt% and Ge: 0.005-0.
Contains at least one selected from 50wt%,
A method for producing a grain-oriented silicon steel sheet with good core loss, the remainder of which is essentially composed of Fe.