JPH02243721A - Production of thin grain-oriented silicon steel sheet having high magnetic flux density by single-stage cold rolling method - Google Patents

Abstract

PURPOSE:To obtain the silicon steel sheet in which secondary recrystallization is perfectly performed and which has superior magnetic properties of product by specifying respective contents of N and acid soluble Al in a slab of a steel with the prescribed composition and the number of rolling passes at specific draft in hot finish rolling and also controlling N, as Al content in the resulting hot rolled plate. CONSTITUTION:A steel slab has a composition consisting of, by weight, 0.060-0.120% C, 2.9-4.5% Si, 0.050-0.090% Mn, 0.020-0.060% S and/or Se, 0.05-0.25% Sn, and the balance acid soluble Al, N, inevitable impurities, and Fe. The content of N contained in this slab is regulated to 0.0050-0.0100% and also the content of acid soluble Al is regulated to a value between [(27/14)XN(%)+0.0035] and [(27/14)XN(%)+0.0100]%. Moreover, in hot finish rolling, rolling pass of >=20% draft is carried out six times or more and the thickness of hot rolled plate is regulated so that draft at the time of cold rolling becomes 85-92%, and further, the content of N, as Al in the above hot rolled plate is controlled to 0.0005-0.0020%, by which the desired thin grain-oriented silicon steel sheet having high magnetic flux density by a single-stage cold rolling method can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for stably manufacturing a thin, high magnetic flux density unidirectional electrical steel sheet with excellent product magnetic properties by a one-stage cold rolling process.

[Conventional technology]

Unidirectional electrical steel sheets are mainly used as soft magnetic +A materials as magnetic core materials for transformers and other electrical equipment, and as magnetic properties, they must have good excitation properties and iron loss properties.

In order to obtain an electrical steel sheet with excellent magnetic properties, it is necessary that the <001> axis, which is the axis of easy magnetization, is highly aligned in the rolling direction. In addition, plate thickness, crystal grain size, resistivity, surface coating, etc. greatly affect magnetic properties.

The directionality of electrical steel sheets has been greatly improved by the intense reduction single-stage cold rolling process in which AIN and MnS function as inhibitors, and now steel sheets with magnetic flux densities of approximately 96% of the theoretical value have been manufactured. There is.

On the other hand, in recent years, reflecting the soaring energy prices, lance manufacturers have started using materials for energy-saving transformers.
We are further increasing our focus on low iron loss magnetic materials.

Low iron tn (as d material, amorphous alloy and 6.
Although the development of high-Sl materials such as 5% 31 alloys is progressing, they have drawbacks in terms of cost, workability, etc. as materials for I-lances.

On the other hand, it is known that the iron loss of electrical steel sheets is greatly influenced by the sheet thickness in addition to the Si content, and that reducing the thickness of the product by chemical polishing or the like reduces the iron loss.

The present inventors previously reported in Japanese Patent Application Laid-Open No. 58-217630 that a silicon steel slab containing acid-soluble Aff, N, and Sn was used as a starting material, and a one-stage cold rolling process under intense pressure accompanied by hot-rolled plate annealing was carried out. disclosed a method for manufacturing a thin, high magnetic flux density unidirectional electrical steel sheet. By this method, a thin high magnetic flux density unidirectional electrical steel sheet with excellent iron loss, especially a sheet thickness of 0.225 m, is produced.
Thin materials up to
By using this material to reduce core loss in transformers, we were able to contribute to energy conservation, which is an issue of the times.

However, since then, the demands of the times for energy conservation have been -
This has led to the need for further improvements in the performance of grain-oriented electrical steel sheets, which are used as materials for transformers. In other words, the plate thickness is 0.17m, which has lower iron loss than the plate thickness of 0.225m/m.
Establishing an inexpensive and stable manufacturing method for thin, high magnetic flux density unidirectional electrical steel sheets of 5 m/m or less has become an urgent issue.

[Problem to be solved by the invention]

It is possible to manufacture 0.175 m/m and 0.150 m/m materials by the method disclosed in JP-A-58-2] and 7630-, but when the plate thickness is 0.175 m/m or less, −
As shown in Tables 8 and 11 of the above publication, -order recrystallization is not complete, and in the case of industrial production, the process yield is low and there are problems with the level and stability of product magnetic properties. There was found.

The present invention provides acid-soluble A4. A silicon steel slab containing N and Sn is used as a starting material, and is cold-rolled to a thickness of 0.12 to 0.17 m/m by a single-stage cold rolling process under heavy reduction accompanied by hot-rolled plate annealing.The product has excellent magnetic properties. The aim is to develop a method for stably manufacturing thin, high magnetic flux density unidirectional electrical steel sheets.

[Means to solve the problem]

The feature of the present invention is that the acid solubility is 1! .

Using a silicon steel slab containing N and Sn as a starting material, a sheet thickness of 0.12~
In a method for manufacturing a thin unidirectional electrical steel sheet cold-rolled to 0.17 m/m, the N contained in the slab and the acid-soluble A
For l, N: 0.0050-0.0100%,
Acid-soluble AN: , ((27/14)×N(χ)+0
．． 0035}~{(27/24) ×N(X) +0
．． 0100}%, and rolling with a rolling reduction of 20% or more is performed for 6 or more baths in finish rolling during hot rolling, and
The thickness of the hot rolled sheet is such that the cold rolling reduction ratio is 85 to 92%, and the Na5A II N content in the hot rolled sheet is 0.000.
By performing hot rolling controlled at 5% to 0.0020%, secondary recrystallization is complete and it is possible to stably manufacture thin, high magnetic flux density unidirectional electrical steel sheets with excellent product magnetic properties.

[For production]

The circumstances leading to the present invention will be explained below based on experimental results.

(Experiment I) C: 0.080%, Si: 3.25%, Mn: 0
．． 075%, S: 0.025%, Sn: 0.13%, N
: 0.0040-0.0120%, acid soluble A#
:0.0100~0.0500%, remainder: substantially Fe
A large number of 200m/'m thick slabs consisting of
heated for 4 hours, extracted from the heating furnace, and roughly rolled.
The bar had a thickness of 40 m/m. Thereafter, finish rolling was performed to a plate thickness of 1.4 m/m by 6 baths of constant reduction rolling. The temperatures before and after finish rolling are 1230-1250℃ and 1
The temperature was 030 to 1050''C. Also, the time required for finish rolling was within 20 seconds.

After finish rolling, it was cooled to 550°C at a rate of about 70°C/sec, and then allowed to cool in the atmosphere. Na5A I contained in hot rolled sheet
N was 0.0010 to 0.0012%. The hot rolled sheets were annealed at 1100° C. for 30 seconds in a N2 atmosphere and then cooled by immersion in water at 100′C. The plate after annealing was pickled and cold rolled to a plate thickness of 0.15 m/m. Then 75%
850℃ in an atmosphere of N2.25%N2 and a dew point of 65℃
Decarburization annealing was performed for 150 seconds. Next, an annealing separator mainly composed of magnesia powder is applied, and 85% H
,, heated to 1200°C in a 15% N2 atmosphere at a heating rate of 25°C/hour, then heated to 1200°C in a N2 atmosphere.
After soaking at 0° C. for 20 hours, the product was cooled, the annealing separator was removed, and tension coating was performed to obtain a product. The magnetic flux density B8 and iron loss W15150 of the product were measured. Next, the coating and glass film were removed and the macrostructure was observed. The relationships between the N and acid-soluble Al contents of the slab, the secondary recrystallization state, B8, and W15150 are shown in FIGS. 1, 2, and 3, respectively.

In FIG. 1, the horizontal axis is the N content, and the vertical axis is the acid-soluble Al content. The secondary recrystallization status is indicated by the symbols 0, Δ, and ×. In the same figure, straight line ab + bc + c
Secondary recrystallization was complete in the region surrounded by d + da. Straight line ab is expressed by the following equation.

Straight line ab; acid-soluble AMχ) = (27/14) ×N
(χ)+0.0100(χ), that is, N: 0.0
050-0.0120%, acid soluble AA: 0.01
00～((27/14) ×N(χ)+0.0100}
%, it was revealed that the secondary recrystallization was complete.

In FIG. 2, the horizontal axis is the N content, and the vertical axis is the acid-soluble Al content. The value of B8 is indicated by the symbols ◯, △, and ×. Straight lines ab, be, and cd in the same figure.

In the area surrounded by da, a score of 8 was obtained.

Straight lines ab and cd are each expressed by the following equations.

Straight line ab: acid-soluble Alχ) = (27/14) xN(χ) +0.0100
(χ) Straight line Cd: Acid-soluble AI = (27/14) ×N(χ) +0.0035(χ
) That is, N: 0.0050-0°0100%, acid-soluble A#: ((27/14)×N(χ)
+0.0035}~{(27/14) ×N(χ) +
It was found that a score of 8, which is better than 8, can be obtained when the content is 0.0100%.

In FIG. 3, the horizontal axis is the N content, and the vertical axis is the acid-soluble Al content. The value of W15150 is indicated by the symbols ○, Δ, and ×. Straight lines ab and bc in the same figure.

Good W15150 in the area surrounded by cd, da
was gotten.

Straight lines ab and cd are each expressed by the following equations.

(lO) Straight line ab: Acid-soluble Al(χ) = (27/14) ×N(χ) +0.0100(χ
) straight line cd; acid-soluble AI (z) = (27/14) ×N (χ) +0.0035
(χ) That is, N: 0.0050 to 0.0100
%, acid-soluble AI2: ((27/14)×N(
χ) +0.00351~((27/14) ×N(
Good W151 when X) -1-0,0100}%
It turned out that 50 was obtained.

From the results in Figures 1, 2, and 3, N: 0.00
50-0.0100%, acid soluble 1! : ((27
/14)×N(χ)10.00351～((27/14
) It was revealed that when xN(χ>+0.0100}%, the secondary recrystallization was complete and good products were obtained for both B8 and W15150.

Despite the complete secondary recrystallization, W15150
In the region where B8 is defective, B8 is low.

That is, on the low Al and high N side, secondary recrystallization is stable, but the directionality is poor and it is difficult to obtain a good iron loss value.

Here, (27/1.4) ×N(χ) is the A7! required when all the N contained in the steel is ΔffN! Corresponds to the content. In the final method that uses AρN as the main inhibitor, the secondary recrystallization phenomenon that affects the magnetic flux density and iron loss value of the product is stronger due to the acid-soluble 〇 content with (27/14) × N (χ) as the base. understood to be affected.

(Experiment ■) C: 0.082%, Si: 3.25%, Mn: 0
．． 070%, S: 0.025%, Sn: 0.14%, N
: 0.0085%, acid soluble Al: 0.0240
%, remainder: A number of slabs of 200 m/m thick consisting essentially of Fe were heated at 1400° C. for 4 hours, extracted from the heating furnace, and rough rolled into bars with a thickness of 40 m/m. After that, it was rolled with a constant reduction ratio of 0.75 to 3.
Finish rolling was performed to various thicknesses of 0 m/m. The time required for finish rolling was within 30 seconds. In this case, before rolling,
By variously changing the cooling conditions during and after rolling, the N
The amount of a5A IN was varied from 0.0001 to 0.0036%. Here, 8IN is the analytical value of the total plate thickness,
The analysis method used the bromine methanol method. (All analyzes of Ai related to the present invention are by the bromine methanol method). These hot rolled sheets were treated in the same manner as in Experiment I to obtain a product.

Next, the magnetic flux density B8 and iron loss W15150 of the product were measured. Next, the coating and glass film were removed and the macrostructure was observed. Hot rolled plate Na5A i,
N, cold rolling reduction and secondary recrystallization status, B8, W1515
0 relationships are shown in FIGS. 4, 5, and 6, respectively.

In FIG. 4, the horizontal axis is the Na5A I N content, and the vertical axis is the cold rolling reduction. Secondary recrystallization status is ○, △,
Indicated by × sign. In the same figure, straight lines ab and bcc
Secondary recrystallization was complete in the region surrounded by d and da. That is, Na5A QN: 0.000
It became clear that the secondary recrystallization was complete when the cold rolling reduction ratio was 1 to 0.0020% and 80 to 92%.

In FIG. 5, the horizontal axis is Na5A I2. It is the N content, and the vertical axis is the cold rolling reduction ratio. The value of B8 is indicated by the symbols ◯, △, and ×. In the same figure, ab, bc, cd
, a score of 8 was obtained in the region surrounded by da.

That is, Na5A I N : 0.0005-0
．． It was revealed that a score of 8, which is good, can be obtained when the cold rolling reduction ratio is 85 to 92%.

In FIG. 6, the horizontal axis is Na5llp, tJ content, and the vertical axis is cold rolling reduction. W 15150 value ○
, △, and ×. In the same figure, ab, be
Good W15 in the region surrounded by , cd, da
150 was obtained.

That is, Na5A I N : 0.0005-0
．． It has become clear that good W15150 can be obtained when the cold rolling reduction is 85 to 92%.

From the results shown in Figures 4, 5, and 6, Na5A I N
:0.0005-0.0020%, cold rolling reduction rate 85-9
When it is 2%, - success or failure crystal is complete, B8, W15150
It has become clear that good products can be obtained.

Despite the complete secondary recrystallization, W15150
In the region where B8 is defective, B8 is low.

From the results of Experiments ■ and Experiment ■, acid-soluble AI2. A silicon steel slab containing NSN is used as a starting material, and a plate thickness of 0.12 to 0.17 m is produced by a single-stage cold rolling process under heavy reduction accompanied by hot-rolled plate annealing.
/m cold-rolled thin unidirectional electrical steel sheet, N contained in the slab and acid-soluble Aj2 are: N: 0.0050 to 0.0100%, acid-soluble Ae: ((27/14 )xN(Z)+0.003
5}〜{(27/14) ×N(χ) +o, oto
o}%, and the thickness of the hot rolled sheet is such that the cold rolling reduction ratio is 85 to 92%, and the Na5A i, N in the hot rolled sheet is
By performing hot rolling to control the content to 0.0005-0.0020%, secondary recrystallization is complete and it is possible to stably manufacture thin, high magnetic flux density unidirectional electromagnetic S+ plates with excellent product magnetic properties. It became clear that it would be.

The Na5A IN content in the hot rolled sheet is 0.0005 to 0.
．． It is not necessarily clear why a product with good secondary recrystallization and excellent magnetic properties can be obtained by performing hot rolling controlled at 0.020%.

When manufacturing a thin, high magnetic flux density unidirectional electrical steel sheet with a cold-rolled plate thickness of 0.17 m/m or less using the single-stage cold rolling method, it is easier to manufacture a thick product than when manufacturing a thick product using the multi-stage cold rolling method. It is thought that the structure and the state of precipitates after hot-rolled sheet annealing have a stronger influence on the product properties. On the other hand, it is thought that the Na5A 12 N content in the hot-rolled sheet has a subtle effect on the structural changes of the steel sheet and the behavior of precipitates during hot-rolled sheet annealing. , ooos to 0.0020%, the most advantageous properties of the steel sheet after hot-rolled sheet annealing with respect to product properties will be obtained.

In addition, the Na5A 42 N content in the hot rolled sheet was set to 0.00.
Methods for controlling the amount to 0.05 to 0.0020% include slab heating conditions, rough rolling conditions, finish rolling conditions, and cooling conditions after finish rolling, and any of these may be used.

(Experiment ■) C: 0.075%, Si: 3.25%, Mn: 0.
070%, S: 0.025%, acid soluble Aj2: 0.
0255%, N: 0.0085%, Sn: 0.1
5%, remainder: A large number of 200 m/m thick slabs made essentially of Fe were hot rolled by varying the bar thickness after rough rolling, the number of passes of finish rolling, and the reduction rate in each pass. , a hot-rolled sheet with a thickness of 1.4 m/m. The temperatures before and after finish rolling are 1230-1250°C and 10°C, respectively.
The temperature was 30 to 1050°C, and the time required for finish rolling was within 20 seconds. Regarding hot rolling conditions other than those mentioned above and other conditions, products were obtained by processing in the same manner as in Experiment I, and the iron product values of the products were measured.

FIGS. 7 and 8 show the relationship between the number of passes of finish rolling in hot rolling, the rolling reduction in each pass, and the iron loss value of the product.

FIG. 7 shows the case of constant reduction rolling. The horizontal axis is the number of rolling passes, and the vertical axis is the rolling reduction ratio. The iron loss value is indicated by a symbol such as ○, △, or ×. As is clear from Figure 7, the reduction rate is 20%.
As described above, it has been found that a good iron loss value can be obtained when the number of rolling passes is 6 or more.

FIG. 8 shows a case where the rolling reduction ratio is different in each pass.

The horizontal axis is the number of rolling passes with a rolling reduction of 20% or more, and the vertical axis is the iron loss.

As is clear from FIG. 8, it has been found that good iron loss can be obtained when the number of rolling passes with a rolling reduction of 20% or more is 6 or more.

As the product plate thickness becomes thinner, the influence of the interfacial reaction on the entire plate thickness becomes relatively larger during high-temperature finish annealing. , it is necessary to precisely build up both sides of the inhibitor texture in the previous process. At the current stage, it is still difficult to quantitatively discuss the ideal state of inhibitors and collective tissues.

As mentioned above, in the finish rolling of hot rolling, the reduction rate is 20
% or more, when the number of rolling passes is 6 or more, strong rolling -
The reason why the thin, high magnetic flux density, unidirectional electrical steel sheet produced by the re-cold rolling process has a good iron loss value is probably due to the fact that it has become advantageous mainly in terms of texture.

Cu or sb was added to the material components shown in Experiment I, Experiment ■, and Experiment ■.
Experiment I for the case where either one or both of
, Experiment ① and Experiment ② were conducted and similar results were obtained.

(Experiment ■) C: 0.083%, Si: 3.25%, Mn: 0
．． 076%, S: 0.025%, Sn: 0.14%, N
: 0.0085%, acid soluble AIl: 0.0235
%, Cu: no addition and 0.01 to 0.20%, remainder:
A large number of 200 m/m thick slabs substantially made of Fe were processed in the same manner as in Experiment I, including hot rolling and subsequent steps.
Got the product. FIG. 9 shows the relationship between Cu content and iron loss value. As is clear from Fig. 9 (Cu: 0.03-0.08
An improvement in iron loss characteristics was observed within the range of %.

(Experiment ■) C: 0.080%, Si: 3.23%, Mn: 0
．． 075%, S2 0.025%, Sn: 0.13%, N
: 0.0085%, acid soluble Al: o, 0230%
, Sb: no additive and 0.001 to 0.050%, remainder: substantially Fe, and a number of slabs with a thickness of 200 m/m were processed in the same manner as in Experiment I, and the products were Obtained. Figure 10 shows the relationship between sb content and iron loss. As is clear from Fig. 10, 3b: 0.005~
Improvement in iron loss characteristics was observed within a range of 0.035%.

Next, the reasons for limiting the components of the slab and the processing conditions of the manufacturing process in the present invention will be described.

C is preferably 0.060 to 0.120%. 0.06
If it is less than 0% or more than 0.120%, secondary recrystallization becomes unstable.

Si is preferably 2.9 to 4.5%. If it is less than 2.9, a good (low) iron loss value cannot be obtained, and if it exceeds 4.5%, workability (ease of cold rolling) deteriorates.

Mn is preferably 0.050 to 0.090%. 0.0
If it is less than 50% or more than 0.090%, secondary recrystallization becomes unstable.

Either one or both of S and Se is 0.020 to 0.
．． 060% is preferred. If it is less than 0.020%, secondary recrystallization becomes unstable, and if it exceeds 0.060%, the iron loss value becomes poor.

Furthermore, particularly excellent product magnetic properties can be obtained when S and Se are added in combination.

Sn is preferably 0.05 to 0.25%. If it is less than 0.05%, secondary recrystallization becomes unstable, and if it exceeds 0.25%, workability deteriorates.

In slab heating, high temperature heating is required to sufficiently dissolve sulfides and nitrides, preferably at 1300"C.
Heating above is desirable.

Preferably, the hot rolled sheet is annealed at 1030 to 1200°C for 10 minutes or less. If the temperature is less than 1030°C, good product magnetic properties cannot be obtained, and if it exceeds 1200°C, secondary recrystallization becomes unstable. Even if the product is annealed for more than 10 minutes, no improvement in the magnetic properties of the product can be expected, which is economically disadvantageous. Note that decarburizing 50 to 250 ppm during annealing is effective in improving the magnetic properties of the product. It is preferable to rapidly cool the material after annealing. Good product properties cannot be obtained without rapid cooling.

The one-stage cold rolling method is preferable because the production cost is significantly lower than the two-stage cold rolling method. The plate thickness after cold rolling is 0.12~0.17m/
m is preferred. If it is less than 0.12 m/m, secondary recrystallization tends to become unstable, and if it exceeds 0.17 m/m, the expected iron loss value cannot be obtained. In addition, during the cold rolling, 20
Maintaining the temperature at 0 to 300°C for 1 to 5 minutes is effective in improving the magnetic properties of the product. It is preferable to use an atmosphere containing nitrogen during the heating up to at least 1000°C during high-temperature finish annealing. If nitrogen is not included, secondary recrystallization becomes unstable.

〔Example〕

Example I C: 0.080%, Si: 3.25%, Mn: 0
．． 076%, S: no additive, 0.015. 0.025%
, Se: no addition, 0.0150.025%, Sn: 0.
13%, N: 0.0045.0.00850.01
10%, acid soluble Ajl! : 0.0150, 0.
01700.0230, 0.0260, 0.030
0%, Cu: no addition, 0.07%, Sb: no addition, 0.
020%, remainder: A large number of slabs with a thickness of 200 m/m consisting essentially of Fe were heated at 1400° C. for 4 hours, extracted from the heating furnace, and rough rolled into bars with a thickness of 40 rn/m. After that, 0.92 and 1.0 were rolled with 6 baths with equal reduction ratio.
The sheets were hot-rolled to thicknesses of 0, 1.31, and 2.43 m/m. The time required for finish rolling was within 30 seconds. In this case, the cooling conditions before finish rolling, during rolling, and after rolling were variously changed. The Na5A 42 N content of the hot rolled sheet is 0.0
It was 0.002% to 0.0035%.

The hot rolled sheet was annealed at 1120°C for 60 seconds, then air cooled and
Cooled by immersion in water at 00'C.

After annealing, the plate is pickled and the plate thickness is 0.12m/m and 0.17m/m.
It was cold rolled to m.

Next, decarburization annealing was performed at 850° C. for 150 seconds in an atmosphere of 75% N2.25% N2 and a dew point of 65° C. Next, an annealing bone removal agent containing magnesia as a main component is applied, and 8
Heating to 1200 °C at a heating rate of 25 °C/h in a 5% H, 15% N2 atmosphere, then in a H2 atmosphere.
After soaking at 1200° C. for 20 hours, the product was cooled, the annealing separator was removed, and tension coating was performed to obtain a product. The magnetic flux density B8 and iron loss W15150 of the product were measured. Next, the coating and glass film were removed and the macrostructure was observed. The results are shown in Table 1. As is clear from Table 1, the slab's N, acid-soluble AI! The secondary recrystallization is complete and B8, W
Both excellent products were obtained.

Furthermore, when the contents of Cu and Sb were within the range of the present invention, even better magnetic properties of the product were obtained.

Example 2 200m/200m of the four types of components A, B, C, and D shown in Table 2
A large number of slabs with a thickness of 1.4 m/m were made into hot rolled plates with a thickness of 1.4 m/m by variously changing the bar thickness after rough rolling in hot rolling, the number of passes of finish rolling, and the reduction rate in each pass. . Regarding the hot rolling conditions and other conditions other than those mentioned above, the process was carried out in the same manner as in Experiment I, a product was obtained, and the iron loss value was measured. Table 3 shows the number of passes of finish rolling, the reduction ratio in each pass, and the iron loss value of the product.

As is clear from Table 3, excellent iron loss values were obtained when the number of rolling passes with a rolling reduction of 20% or more was 6 or more in finish rolling during hot rolling.

Table [Effects of the Invention] Since the present invention is configured as described above, the silicon steel slab containing acid-soluble Al, N, and Sn is used as a starting material, and a one-stage cold rolling process under heavy reduction accompanied by hot-rolled plate annealing is applied. In the method of manufacturing a thin unidirectional electrical steel sheet cold-rolled to a thickness of 0.12 to 0.17 m/m, the crystals are perfect,
It is now possible to stably manufacture thin, high magnetic flux density, unidirectional electrical steel sheets with excellent product magnetic properties.

[Brief explanation of drawings]

Figure 1 shows the N content (horizontal axis) and acid-soluble Aj of the slab.
2 content (vertical axis) and secondary recrystallization status (indicated by ○, X, etc.)
FIG. Figure 2 shows the N content (horizontal axis) and acid-soluble AA of the slab.
It is a diagram showing the relationship between the content (vertical axis) and the magnetic flux density B8 of the product (indicated by ◯, X, etc.). Figure 3 shows the N content of the slab (horizontal axis) and the acid-soluble A7
! Content (vertical axis) and product iron loss W1.5150 (○, ×
FIG. FIG. 4 is a diagram showing the relationship between the Na5A I N content (horizontal axis) and cold rolling reduction (vertical axis) of the hot-rolled sheet and the secondary recrystallization status (indicated by ○, ×, etc.). FIG. 5 is a diagram showing the relationship between the Na5A I N content (horizontal axis) and cold rolling reduction (vertical axis) of the hot-rolled sheet and the magnetic flux density B8 (indicated by ○, ×, etc.) of the product. Figure 6 shows the Na5A j2N (horizontal axis) and cold rolling reduction (vertical axis) of the hot rolled sheet and the iron loss W15150 (○,
FIG. FIG. 7 is a diagram showing the relationship between the number of passes of uniform reduction rate finish rolling, the reduction rate in each pass, and the iron loss value of the product (indicated by ◯, ×, etc.) in hot rolling. Figure 8 shows a finishing rolling ratio of 20% in hot rolling.
FIG. 3 is a diagram showing the relationship between the number of passes described above and the core loss value of the product. FIG. 9 is a diagram showing the relationship between the Cu content of the slab (horizontal axis) and the amount of change in iron loss W15150 of the product due to Cu addition (vertical axis). FIG. 10 is a diagram showing the relationship between the sb content of the slab (horizontal axis) and the amount of change in iron loss W15150 of the product due to sb addition (vertical axis).

Claims (1)

[Claims] 1. C: 0.060 to 0.120% by weight, Si: 2
．． 9-4.5%, Mn: 0.050-0.090%, S
or Se or both: 0.020 to 0.0
A slab consisting of 60%, Sn: 0.05-0.25%, remainder: acid-soluble Al, N, Fe and unavoidable impurities is heated at high temperature and hot-rolled to obtain a hot-rolled plate of 1030-1200%.
Annealed within 10 minutes at a temperature range of ℃, rapidly cooled, and then cold rolled to a plate thickness of 0.12 to 0.17 m/cm after cold rolling.
m, perform decarburization annealing in a humid atmosphere containing hydrogen, apply an annealing separator mainly composed of magnesia, and perform high-temperature finish annealing using an atmosphere containing nitrogen to at least 1000 ° C during heating, In the method for manufacturing a thin unidirectional electrical steel sheet that is subjected to tension coating, the N and acid-soluble Al contained in the slab are N: 0.0050 to 0.0100.
%, acid-soluble Al: {(27/14)×N(%)+0.
0035}~{(27/14)×N(%)+0.010
0}%, and the rolling reduction rate is 20 in finish rolling during hot rolling.
% or more rolling for 6 passes or more, and the cold rolling reduction ratio is 8
One-stage cold rolling, characterized in that the thickness of the hot-rolled sheet is 5 to 92%, and further hot rolling is performed to control the NasAlN content in the hot-rolled sheet to 0.0005 to 0.0020%. A method for producing thin, high magnetic flux density, unidirectional electrical steel sheets with excellent magnetic properties. 2. C: 0.060-0.120%, Si: 2 in weight%
．． 9-4.5%, Mn: 0.050-0.090%, S
or Se or both: 0.020 to 0.0
60%, Sn: 0.05-0.25%, Cu: 0.03
~0.08% or Sb: 0.005~0.035%, or both, the remainder: A slab consisting of acid-soluble Al, N, Fe, and inevitable impurities is heated at high temperature, hot rolled, and hot rolled. The rolled plate is heated in the temperature range of 1030 to 1200℃ for 10
Annealed within 1 minute, rapidly cooled after annealing, then cold rolled, with a plate thickness of 0.12 to 0.17 m/m after cold rolling, decarburized annealed in a humid atmosphere containing hydrogen, and magnesia Apply the annealing separator, which is the main component, and at least 10
In a method for producing a thin grain-oriented electrical steel sheet in which high-temperature finish annealing is performed in an atmosphere containing nitrogen up to 0.00°C and tension coating is applied, the N content of the slab and acid-soluble Al are N: 0.0050 to 0.000°C. 0100%, acid-soluble Al: {(27/14) x N (%) + 0.0035} ~
{(27/14)×N(%)+0.0100}%,
In addition, in finishing rolling in hot rolling, rolling with a rolling reduction of 20% or more is performed for 6 passes or more, and the cold rolling reduction is 85 to 9.
The thickness of the hot-rolled sheet is 2%, and the Nas content in the hot-rolled sheet is
A method for producing a thin, high magnetic flux density unidirectional electromagnetic steel sheet with excellent product magnetic properties by a one-stage cold rolling process, characterized in that hot rolling is carried out to control the AlN content to 0.0005 to 0.0020%.