JPH0742501B2 - Manufacturing method of non-oriented electrical steel sheet with excellent magnetic properties before and after magnetic annealing - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a non-oriented electrical steel sheet which is excellent in both iron loss and magnetic flux density before and after magnetic annealing.

(Prior Art) Non-oriented electrical steel sheets are used as iron core materials for large-sized, medium-sized rotating machines, general-purpose motors, automobile motors, household electric motors, transformers, and the like. This steel sheet is graded according to the magnetic characteristic level, and is used properly according to the purpose of the desired electrical equipment product.

In order to save energy in recent years, improve the characteristics of electric devices, and reduce the size, it is strongly desired to improve the magnetic properties of iron core materials used in these electric devices. In particular, it is important to further improve the magnetic properties of intermediate to low grade non-oriented electrical steel sheets used for general-purpose motors, motors for automobiles, motors for home appliances and the like.

The method of using the electromagnetic steel sheet is that after punching coil or sheet-shaped products into parts shapes for various electric devices at customers,
It is laminated and formed into a predetermined core.
There are two cases, that is, the case where magnetic annealing for the purpose of improving magnetism is carried out and the case where it is not carried out.

With this magnetic annealing, the steel sheet is distorted by punching by a consumer, and this distortion causes the iron loss to deteriorate significantly. Therefore, heat treatment at about 750 ° C. × 2 hr is performed in a nitrogen atmosphere for the purpose of removing this strain and improving the iron loss by performing primary grain growth of the steel sheet.

In general, when non-oriented electrical steel sheets are used without magnetic annealing, recently low-oriented non-oriented electrical steel sheets are used for the purpose of reducing the cost of electric manufacturers, and magnetic annealing is performed after lamination. As a result, the number of cases of improving the magnetic level of medium- to high-grade non-oriented electrical steel sheets and using it has increased.

The percentage of magnetic annealing performed on such medium- and low-grade non-oriented electrical steel sheets has been increasing year by year, and now about 70% is used after magnetic annealing. For this reason, electromagnetic steel sheets are required to exhibit excellent magnetism before and after the magnetic annealing, and competition for development of materials having such characteristics is being developed.

By the way, the electric power loss generated in the electric equipment is mainly iron loss, and depends on the iron loss of the non-oriented electrical steel sheet of the material. The iron content can be lowered by increasing the Si content, but this causes an increase in cost and further lowers the magnetic flux density. Since the decrease of the magnetic flux density requires a large exciting current, the power loss becomes large in a general-purpose motor or the like that is frequently started and stopped, which is a problem.

Conventionally, various hot rolling techniques for improving magnetic properties have been proposed in the production of non-oriented electrical steel sheets. Japanese Patent Publication No. 56-18045 and Japanese Patent Publication No. 56-33451 disclose that a high temperature slab as continuously cast is secured in the temperature range of 801 to 1050 ° C. for both surface temperature and center temperature for 40 minutes or more. A method for manufacturing a non-oriented electrical steel sheet is disclosed, which is basically based on the purpose of detoxifying the agglomeration treatment.

In addition, Japanese Examined Patent Publication No. 60-56403 discloses that Si is 0.3% to 2.0%.
It is disclosed that after the ultra low carbon steel slab containing is hot-rolled, it is annealed at a high temperature for a short time at a temperature of 800 ° C. or more and within 2 minutes.

Further, in Japanese Patent Laid-Open No. 63-210237, there are problems in carrying out high-temperature winding, that is, the problem of descaling due to an increase in the amount of scale formation, and the magnetic characteristics due to nonuniform temperature in the coil. In order to solve the problem of variation, high-purity steel is used as a starting material, and hot rolling is completed in the low temperature region of the ferrite region of 700 ° C or higher to accumulate sufficient strain in the hot rolled sheet, It is disclosed that the hot-rolled sheet is recrystallized and grains are grown by winding at 680 ° C.

(Problems to be Solved by the Invention) However, Japanese Patent Publication No. 56-18045 and Japanese Patent Publication No. 56-33451 described above.
It is clear that the techniques disclosed in Japanese Patent Publication No. 60-56403 and Japanese Patent Publication No. 56-56403 are expensive because of the annealing of the hot rolled sheet.

Further, in the technology disclosed in Japanese Patent Laid-Open No. 63-210237,
No mention is made of the slab heating conditions before hot rolling, and the magnetic properties vary greatly depending on the slab heating conditions.

It is an object of the present invention to advantageously solve the above-mentioned problems of the prior art and to provide a novel method for manufacturing a non-oriented electrical steel sheet to the above technology.

(Means for Solving the Problem) In order to find a measure that can expect the same effect as performing hot-rolled sheet annealing, the inventors of the present invention particularly in terms of material components, heating conditions, finish rolling, and winding. As a result of various experiments on the conditions, the following findings were obtained.

The Mn in the material is controlled between 0.1 and 0.4%, and at the same time, S is set to 0.
In addition to lowering to 0050% or less, by lowering the heating temperature of the slab to 1100 ° C. or less, fine precipitation of MnS during hot rolling can be prevented, and recrystallization can be sufficiently advanced in the hot rolling stage. The grain growth of crystal grains can be greatly promoted, and as a result, iron loss can be improved.

In order to grow grains in the hot rolled sheet stage, it is important to raise the exit temperature of the finish rolling mill to below the Ar ₃ transformation point as much as possible, but by lowering the C in the steel composition to below 0.0050%. , It is possible to move this Ar ₃ transformation point to the high temperature side.

In other words, by reducing the content of steel to less than 0.0050%
The Ar ₃ transformation point is moved to the high temperature side, and the temperature immediately below this transformation point is raised in absolute value, and as a result, rolling in a higher temperature region becomes possible and crystal grain growth can be promoted. At the same time, the texture of the hot rolled sheet is also improved.

The improvement of the texture of this hot-rolled sheet was made by further increasing the heating temperature to 1100.
℃ below, and the finish rolling mill outlet temperature above the Ar
The combination of controlling to the highest temperature side (range shown by equation (1)) as much as possible at _three transformation points or less makes a great progress, and particularly brings about a great improvement in magnetic flux density.

As described above, by setting the slab heating temperature in the hot rolling stage to 1100 ° C. or lower and keeping the finish rolling mill outlet temperature in the range of the formula (1), the grain growth and texture of the crystal grains in the hot rolling stage can be improved. It can be remarkably improved, and thereby the iron loss and the magnetic flux density can be improved.

The present invention is based on the above findings, and the gist of the present invention is as follows.

(1)% by weight C: 0.005% or less Si: 1.5% or less Al: 0.5% or less Mn: 0.1 to 0.4% P: 0.15% or less S: 0.0050% or less The balance is iron and inevitable impurities When hot rolling the slab, bake the slab to 1100 ° C or below,
After that, the finish rolling mill outlet temperature Y (° C) is controlled within the temperature range shown by the formula (1), and then it is cooled by water injection and wound at a temperature of 650 ° C or lower, followed by descaling, cold rolling and annealing. A method for producing a non-oriented electrical steel sheet having excellent magnetic properties before and after magnetic annealing.

870 + 80 x Si (%) ≥ Y ≥ 820 + 80 x Si (%) (1) Formula (2) Weight% C: 0.005% or less Si: 1.5% or less Al: 0.5% or less Mn: 0.1 to 0.4% P: 0.15 % Or less S: 0.0050% or less, Cu: 0.01 to 1.0% Sn: 0.02 to 0.20% Sb: 0.010 to 0.30% B: 0.0003 to 0.0050% One or more, and the balance is iron. When hot rolling an electromagnetic steel slab consisting of unavoidable impurities, the slab is baked to 1100 ° C or lower, and then the finish rolling mill outlet temperature Y
Before and after magnetic annealing, characterized in that (° C) is controlled within the temperature range indicated by the formula (1), and then water cooling is performed and winding is performed at a temperature of 650 ° C or less, followed by descaling, cold rolling and annealing. For manufacturing a non-oriented electrical steel sheet having excellent magnetic properties.

870 + 80 × Si (%) ≧ Y ≧ 820 + 80 × Si (%) (1) Formula (Operation) The details of the present invention will be described below.

FIG. 1 is experimental data showing the relationship between the heating temperature in the hot rolling step, the exit temperature of the finish rolling mill, and the magnetic properties before and after magnetic annealing under a low S of 0.0050% or less.

This is C: 0.003%, Si: 0.15%, Mn: 0.12%, P: 0.07
%, S: 0.0030%, solAl: 0.0015% molten steel was made into a slab with a thickness of 250 mm by a continuous casting machine, and in the subsequent hot rolling process, the heating temperature was 1050 ℃, 1100 ℃, 1150 ℃. As for the level, the finish rolling mill outlet temperature is shifted to the lower limit of the formula (1) at 820 ° C, and as the temperature to enter the formula (1), it is divided into two levels of 870 ° C and 6 levels in total, and the subsequent winding is performed at 620 ° C. , 2.5 mm thick hot-rolled sheet, then descaled pickling, cold rolled to a sheet thickness of 0.5 mm thickness, further continuous annealing at 750 ℃ × 30 seconds was carried out, before and after magnetic annealing of the product The results of measurement of iron loss and magnetic flux density are shown.

First, regarding the influence of the heating temperature, it can be seen that both the iron loss before magnetic annealing and the iron loss after magnetic annealing are greatly improved by heating at a low temperature of 1100 ° C. or less. And this tendency becomes large especially about the iron loss value after magnetic annealing.

Similarly, regarding the magnetic flux density, when the effect of heating temperature is also examined, at 820 ° C, where the exit temperature of the finishing mill deviates from equation (1), the values before and after magnetic annealing are slightly improved by low temperature heating below 1100 ° C. Is recognized. On the other hand, when the same comparison is performed at the finish rolling mill outlet temperature of 870 ° C included in the formula (1), the magnetic flux density is remarkably improved in the low temperature heating region of 1100 ° C or lower.

Thus, in the magnetic flux density, 11 before and after magnetic annealing.
It can be seen that a significant improvement can be achieved by combining low-temperature heating at 00 ° C. or less and the finish rolling mill outlet temperature included in formula (1).

Figure 2 shows the relationship between heating temperature, finish rolling mill outlet temperature and magnetic flux density before magnetic annealing in more detail. In the case of high temperature heating above 1150 ℃ (1150 ℃), the magnetic flux density before magnetic annealing is (1 In the temperature range included in the equation), there is little margin for improving the magnetic flux density even if the temperature is raised to just below the Ar ₃ transformation point.
However, when heating at a low temperature of 1100 ° C or lower (1050 ° C), the magnetic flux density is improved by rolling in the combination of the regions shown in equation (1), and the tendency continues just below the Ar ₃ transformation point. There is. It is the present invention that the magnetic flux density is significantly improved by selecting such a combination of the heating temperature and the finishing temperature.

In other words, by improving the iron loss before and after magnetic annealing by low temperature heating below 1100 ° C, and combining this low temperature heating and controlling the finish rolling mill outlet temperature within the temperature range shown in equation (1) The present invention has made it possible to improve the magnetic flux density before and after annealing.

This phenomenon will be described below.

In the photograph of Fig. 3, the heating temperature of Fig. 1, 1150 ℃, 1050 ℃,
The metal phase photograph of the recrystallized structure of the material at four stages of the finish rolling mill outlet temperature, 820 ℃ and 870 ℃ at the hot rolled sheet stage is shown. As can be seen, the recrystallization grain size is increased by heating at a low temperature of 1100 ° C or lower (1050 ° C). Also, finishing mill exit temperature conditions, from the following Ar ₃ transformation point, further particle size increases by bringing the higher temperature side of 832 ° C. or higher (870 ° C.), the material combines the two, i.e. 1100 Low temperature heating below ℃,
In the material treated in the high temperature finishing area shown by the equation (1),
High temperature heating of 1150 ° C or higher (1150 ° C), which is the conventional general operating condition, resulted in a double grain size of 40μ compared to 22μ of the grain size at low temperature finishing of 830 ° C or lower (820 ° C). Can be observed.

The photograph in Fig. 4 shows Mn at the hot rolled sheet stage due to the difference in heating temperature.
Although it is a microstructure photograph showing the difference in the precipitation state of S, it can be seen that fine MnS precipitation is not observed by heating at a low temperature of 1050 ° C as seen.

The above phenomenon shows that solidification of MnS during slab heating is prevented by heating at a low temperature of 1050 ° C, and thus fine MnS precipitation that occurs during hot rolling is suppressed, and recrystallization in the alpha single-phase region is suppressed. It is easy to proceed and the finish rolling mill outlet temperature
In the hot rolled sheet after winding, by the combination of the two, which is in the region below the Ar ₃ transformation point and further toward the high temperature side to further promote the recrystallization in the hot rolled sheet in the alpha single phase region. The grain growth of the crystal grains can be achieved.

Fig. 5 shows the strength of each oriented grain in the texture of the hot-rolled sheet produced under these 4 conditions. The maximum strength of the (100) oriented grain that hinders the improvement of the magnetic flux density is 1100 ° C or less. (1050
(° C) low temperature heating and high temperature finishing included in formula (1) (87
It can be seen that the texture of the hot-rolled sheet is improved by the combination of (0 ° C), which is significantly decreased.

In addition to the grain growth of the crystal grains of the hot rolled sheet, the combination of the low temperature heating of 1100 ° C or less and the rolling method of high temperature finishing within the range shown in formula (1) before and after the magnetic annealing can be seen from the direction of the texture. It can be seen that the iron loss and magnetic flux density are improved.

The steel component composition applied in the present invention will be described below.

C significantly reduces the magnetic properties by aging precipitation. Therefore, in the present invention, the upper limit is set to 0.0050% as a range in which the influence of magnetic aging is not exerted.

Further, in this patent, by aiming as high temperature as possible below the Ar ₃ transformation point and as high as possible, grain growth of recrystallized grains of the hot rolled sheet immediately after finish rolling and hot rolled sheet texture improvement are also characterized. The higher the finishing temperature, the greater this effect. Therefore, lowering the C value raises the Ar ₃ transformation point temperature.
Temperature rise due to halving from 0.010% to 0.005% is about
30 ° C.), which results in an increase in the finish rolling temperature and a greater effect of improving the magnetism, and is designed to have a low C of 0.005% or less.

Further, when C is high, improvement in iron loss due to magnetic annealing is very small, and from this point as well, low C is essential in the present invention.

Si is contained in order to reduce iron loss due to an increase in specific resistance. However, if the amount is increased, the magnetic flux density is lowered, and the cost becomes high, so the upper limit is made 1.5%. The lower limit need not be specified, but is preferably 0.05%.

There are two types of Al: when it is contained to reduce iron loss due to an increase in specific resistance, and when it is used as a deoxidizing material to reduce the content of oxidizing inclusions in steel as much as possible in order to lower iron loss. There is a purpose to use, but the reason for setting 0.5% as the upper limit is
This is because the cost increase becomes too large for the effect.

Mn reacts with S to form growth of MnS, which has the function of inhibiting the growth of primary recrystallized grains to exhibit magnetic properties. Therefore, measures for lowering S have been conventionally implemented.
In recent years, the technology for reducing S in the steelmaking stage has been improved, and in this patent, the reason for limitation in the S reduction area of 0.0050% or less will be described.

Under the high S condition of S of 0.0050% or more, the amount of precipitation of MnS during hot rolling is large, grain growth of crystal grains in the hot rolling stage and the annealing stage is difficult to proceed, and iron loss is deteriorated. However, in the S-reduced region of 0.0050% or less, the precipitation amount of MnS is lower than that in the high-S region, and this phenomenon is reduced. Therefore, until recently, it was considered that there is no reason for limiting the Mn value if the S value is lowered.

However, the present inventors have found a characteristic relationship between the Mn value and the MnS precipitation state in the low S region of 0.0050% or less. This relationship means that the iron loss before and after magnetic annealing is deteriorated when the Mn value is less than 0.1%.

As a result of various investigations, in such a low S region, the Mn value is
It was confirmed that fine MnS precipitation started in the hot-rolled sheet stage when the region was lower than 0.1%.

Since the characteristic behavior of MnS in such a reduction in S was observed, the lower limit of the Mn value was set to 0.1%.

Next, regarding the upper limit, although increasing the Mn value has the effect of lowering the iron loss without deteriorating the magnetic flux density, but increasing the content increases the cost, so it is made 0.4% or less.

P has the effect of increasing the hardness of the steel sheet and improving the internal drawability, but on the other hand, if its content increases, core loss and magnetic flux density deteriorate, so it is made 0.15% or less.

It has already been described that S forms MnS with Mn and inhibits grain growth in the hot rolling step and the annealing step. Therefore, in recent years, reduction of S has been promoted, and it is considered that the lower the content, the better the magnetic characteristics. Therefore, the upper limit was set to 0.0050% in consideration of economic aspects in the current melting technology of clean steel.

Further, in the present invention, if necessary Cu: 0.01 ~ 1.0
%, Sn: 0.02-0.20%, Sb: 0.010-0.30%, B: 0.0003-
One or more of 0.0050% is contained.

Cu, Sn, Sb and B all affect the texture and have the effect of increasing the magnetic flux density. Cu is 0.010% to bring out this effect.
Above, Sn is 0.02% or more, Sb is 0.010% or more, B is 0.0003
% Or more is required. On the other hand, if the content of these elements increases, iron loss deteriorates, so Cu is 1.0%, Sn is 0.20%, and Sb is 0.3%.
The upper limits of 0% and B are 0.0050%.

[Slab heating temperature]

The condition of this step is that the actual temperature of the slab at the time of extracting the heating furnace is 1100 ° C or lower. The present invention, as described above,
A major feature is that the magnetic properties before and after magnetic annealing are remarkably improved by improving the two points of promoting recrystallization and grain growth in the hot rolling stage and improving the texture. In order to sufficiently promote recrystallization and grain growth in the hot rolling stage, it is important to prevent fine precipitation of MnS in the hot rolling stage. This fine precipitation of MnS depends, of course, on the contents of Mn, S, etc. in the steel, but the behavior is that solution treatment of MnS, AlN occurs during the heating stage, and this solution is heat-treated. It is that it is finely precipitated during rolling. Therefore, it is desirable that the heating temperature is as low as possible, and the temperature at which the solution of MnS in this component system is prevented is 1100 ° C. or lower.

Also, it has already been mentioned that the effect of improving the texture appears in combination with the heating temperature and the exit temperature of the finishing mill, but in order to improve the texture, the heating temperature is 1100 ° C.
The following needs to be controlled.

In particular, although the lower limit does not specify the temperature, it is possible to carry out hot rolling in which the thickness and width of the hot rolled sheet can be obtained accurately, and the temperature range of formula (1) can be secured at the exit of the finishing mill. It only needs to be in the range.

[Hot rolling temperature]

This step is conditioned on controlling the finish rolling mill outlet temperature within the range shown in the equation (1). As described above, the present invention promotes recrystallization and grain growth in the hot-rolled sheet stage by controlling the low-temperature heating at 1100 ° C. or lower and controlling the exit temperature of the finishing mill within the temperature range shown in equation (1). There are two major features in that, the maximum strength of the (100) oriented grains, which hinders the improvement of the magnetic flux density, is lowered.

The effect of the present invention cannot be sufficiently obtained in a region outside the range of the formula (1). On the other hand, within the range of the formula (1), it is desirable that the temperature is as high as possible for improving the magnetism.

If the value exceeds the upper limit of the expression (1), the effect of the present invention cannot be sufficiently obtained for the following reason. The improvement of iron loss and magnetic flux density is proportional to the degree of grain growth of crystal grains at the hot rolled sheet stage.
This grain growth is determined by the finish outlet temperature in the α region × time, but the time from the finish outlet to the winding is almost constant for each equipment due to equipment restrictions and temperature deviation.

Under these circumstances, if the finish outlet temperature exceeds the upper limit of the formula (1), the temperature exceeds the transformation point temperature and becomes a two-phase region of α + γ,
The transformation point is changed in the time from the finish outlet to the winding, and as a result, the time spent for grain growth in the α region is shortened, and the effect of the present invention cannot be sufficiently obtained. .

〔Winding〕

The condition is that the winding temperature is within 650 ° C.

From the standpoint of expecting recrystallization and grain growth of the hot-rolled sheet, it is advantageous to wind the coil at a high temperature. Specifically, it is said that winding at a temperature of 680 ° C or higher is effective. However, it is a well-known fact that such winding at a high temperature causes deterioration in descaling property and variation in characteristic values within the unit coil.

In the present invention, the upper limit is set to 650 ° C. in order to prevent various problems caused by the high temperature winding of 680 ° C. or higher.
Further, the lower limit is not particularly limited, but in winding at a low temperature of 500 ° C. or less, cooling after the exit of the finish rolling mill becomes too rapid and the winding shape is deteriorated, so the lower limit is preferably about 500 ° C. .

[Example 1] C: 0.0030%, Si: 0.15%, Mn: 0.15%, P: 0.07%, solAl:
Steel with a composition of 0.0014% and S: 0.0032% was smelted using a converter and RH, and then a continuous casting machine was used to form a 250 mm thick slab. Then, heating conditions and finish in the hot rolling process were performed. By rolling the rolling conditions to those shown in Table 1, a hot rolled sheet having a thickness of 2.5 mm was obtained.

The hot rolled sheet was pickled, descaled, rolled by a cold rolling mill to a product sheet thickness of 0.50 mm, and continuously annealed at 750 ° C. for 30 seconds to obtain a finished product.

From each product obtained in this way, 8 Epstein test pieces of 30 mm x 280 mm from the rolling direction and 8 from the direction perpendicular to the rolling direction.
A total of 16 sheets were sampled and the magnetic properties before and after magnetic annealing were measured.

The magnetic annealing conditions were 750 ° C. × 2 hours in a nitrogen atmosphere.

[Example 2] C: 0.0035%, Si: 0.80%, Mn: 0.22%, P: 0.02%, solAl:
Steel with a composition of 0.0018% and S: 0.0035% was smelted using a converter and RH, and then a continuous casting machine was used to form a slab with a thickness of 250 mm, and then heating conditions and finish rolling conditions in the hot rolling process. Was rolled under the conditions shown in Table 2 to obtain a hot-rolled sheet having a thickness of 2.3 mm.

The hot rolled sheet was pickled, descaled, rolled by a cold rolling mill to a product sheet thickness of 0.50 mm, and continuously annealed at 790 ° C. for 30 seconds to obtain a finished product.

From each product obtained in this way, 8 Epstein test pieces of 30 mm x 280 mm from the rolling direction and 8 from the direction perpendicular to the rolling direction.
A total of 16 sheets were sampled and the magnetic properties before and after magnetic annealing were measured.

The magnetic annealing conditions were 750 ° C. × 2 hours in a nitrogen atmosphere.

[Example 3] C: 0.0035%, Si: 0.50%, Mn: 0.20%, P: 0.07%, solAl:
Aiming at a composition of 0.0016% and S: 0.0030%, Cu, Sn,
One or more elements of Sb and B were added to produce a 250 mm thick slab having the components shown in Table 3.

In the subsequent hot rolling process of these slabs, heating conditions and finish rolling conditions were changed to those shown in Table 4 to obtain hot rolled sheets having a thickness of 2.3 mm.

The hot-rolled sheet was pickled, descaled, rolled to a product sheet thickness of 0.50 mm by a cold rolling mill, and continuously annealed at 780 ° C. for 30 seconds to obtain a finished product.

From each product obtained in this way, 8 Epstein test pieces of 30 mm x 280 mm from the rolling direction and 8 from the direction perpendicular to the rolling direction.
A total of 16 sheets were sampled and the magnetic properties before and after magnetic annealing were measured.

The magnetic annealing conditions were 750 ° C. × 2 hr in a nitrogen atmosphere.

(Effects of the Invention) As described above, according to the present invention, it is found that a non-intermediate grain-oriented electrical steel having excellent magnetic properties before and after magnetic annealing of a low-grade product can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing changes in the magnetic properties before and after magnetic annealing when the slab actual temperature at the time of extracting a heating furnace in the hot rolling process and the finish rolling mill outlet temperature are changed. Fig. 2 shows the relationship between the finish rolling mill outlet temperature and the magnetic flux density before magnetic annealing when the slab actual temperature during extraction of the heating furnace in the hot rolling process is set to two levels of 1060 to 1085 ° C and 1150 to 1170 ° C. The figure which showed. Fig. 3 Micrograph (× 50) shows 4 levels in total, slab actual temperature of 1050 ℃ and 1150 ℃ at the time of furnace extraction during hot rolling process and finish rolling exit temperature of 820 ℃ and 870 ℃. 3 shows a metallographic structure of a hot-rolled sheet of a material subjected to the hot-rolling conditions of No. Fig. 4 Electron micrograph (× 3000) shows the structure of MnS crystals (precipitation state) in the hot-rolled sheet when the actual slab temperature during extraction in the heating furnace in the hot-rolling process is two levels of 1050 ° C and 1150 ° C. Indicates. Fig. 5 shows two levels of actual slab temperature of 1050 ℃ and 1150 ℃ during extraction of the heating furnace in the hot rolling process, and the finish rolling outlet temperature is 820.
2 shows the results of measuring the X-ray intensity of the texture of a hot-rolled sheet made of a material subjected to a total of 4 hot-rolling conditions of 2 ° C. and 870 ° C.

Claims (2)

[Claims] 1. By weight% C: 0.005% or less Si: 1.5% or less Al: 0.5% or less Mn: 0.1 to 0.4% P: 0.15% or less S: 0.0050% or less, with the balance being iron and unavoidable impurities When hot rolling an electromagnetic steel slab, the slab is baked to 1100 ° C or below,
After that, the finish rolling mill outlet temperature Y (° C) is controlled within the temperature range shown by the formula (1), and then it is cooled by water injection and wound at a temperature of 650 ° C or lower, followed by descaling, cold rolling and annealing. A method for producing a non-oriented electrical steel sheet having excellent magnetic properties before and after magnetic annealing. 870 + 80 × Si (%) ≧ Y ≧ 820 + 80 × Si (%)… (1) formula 2. C: 0.005% or less by weight% Si: 1.5% or less Al: 0.5% or less Mn: 0.1 to 0.4% P: 0.15% or less S: 0.0050% or less, further Cu: 0.01 to 1.0% Sn: 0.02-0.20% Sb: 0.010-0.30% B: 0.0003-0.0050% One or more types are contained, and the balance is made of iron and unavoidable impurities. Baked below 1100 ℃, then finish thickening machine exit temperature Y
Before and after magnetic annealing, characterized in that (° C) is controlled within the temperature range indicated by the formula (1), and then water cooling is performed and winding is performed at a temperature of 650 ° C or less, followed by descaling, cold rolling and annealing. For manufacturing a non-oriented electrical steel sheet having excellent magnetic properties. 870 + 80 × Si (%) ≧ Y ≧ 820 + 80 × Si (%)… (1) formula