KR100683471B1 - Method for processing non-directional electromagnetic steel plate and hot rolling steel plate with material for the non-directional electromagnetic steel plate - Google Patents

Abstract

In mass%, C: 0.01 to 0.2%, Si: 3% or less, Mn: 0.05 to 3.0%, Al: 1% or less, and N: 0.005% or less, and (1) P: 0.2% or less and S: 0.01% or less or (2) P + 100 × S + 300 × Se ≦ 0.5, and the remainder is hot rolled to form a composition of Fe and inevitable impurities, followed by hot rolled annealing, followed by rolling to the final plate thickness. When the non-oriented electrical steel sheet is produced by a series of processes of decarburizing annealing and finishing annealing, the hot rolled sheet annealing is performed using A _c3. By carrying out in the temperature range more than a point, the non-oriented electrical steel plate with high magnetic flux density and low iron loss is obtained.

Description

METHOD FOR PROCESSING NON-DIRECTIONAL ELECTROMAGNETIC STEEL PLATE AND HOT ROLLING STEEL PLATE WITH MATERIAL FOR THE NON-DIRECTIONAL ELECTROMAGNETIC STEEL PLATE}

1 is in the first experiment, hot rolled sheet annealing temperature (horizontal axis: ℃): a view showing the relationship of (B _50, unit T and the vertical axis) and the magnetic flux density.

FIG. 2 is a diagram showing the relationship between the hot-rolled sheet annealing temperature (horizontal axis: ° C.) and the magnetic flux density (vertical axis: B ₅₀ , unit T) in Experiment 2. FIG.

3 is a graph showing the relationship between the amount of C in the steel (horizontal axis: mass%) and the magnetic flux density (vertical axis: B ₅₀ , unit T) in Experiment 3. FIG.

4 is a graph showing the relationship between the amount of C in the steel (horizontal axis: mass%) and the magnetic flux density (vertical axis: B ₅₀ , unit T) in Experiment 4. FIG.

FIG. 5 is a diagram illustrating a relationship between final rolling temperature (horizontal axis: ° C.) and magnetic flux density (vertical axis: B ₅₀ , unit T) in Experiment 5. FIG.

FIG. 6 is a diagram illustrating a relationship between final rolling temperature (horizontal axis: ° C.) and magnetic flux density (vertical axis: B ₅₀ , unit T) in Experiment 6. FIG.

FIG. 7 is a diagram showing the relationship between the cooling rate (horizontal axis: ° C / s) and the magnetic flux density (vertical axis: B ₅₀ , unit T) after hot-rolled sheet annealing in Experiment 7. FIG.

FIG. 8 shows the relationship between the amount of S, P, Se and iron loss (vertical axis: W _15/50 , unit W / kg) in the experiment 9 as parameters (P + 100 × S + 300 × Se). It is a figure shown as (horizontal axis).

The present invention relates to an advantageous method for producing non-oriented electrical steel sheet, which is preferably used for iron core materials such as motors, EI cores, and the like.

In recent years, as the demand for energy saving increases, the demand for high efficiency of the motor also increases. In order to achieve the high efficiency of a motor, since the high performance of the electrical steel sheet used as a core material is indispensable, the electrical steel sheet with high magnetic flux density and low iron loss is strongly requested | required so far.

In order to increase the magnetic flux density of the electrical steel sheet, it is effective to coarsen the crystal grains before cold rolling. Therefore, a technique of applying a skin path to the hot rolled steel sheet and performing annealing (for example, Japanese Patent Publication No. 45-22211) or hot rolling A technique has been proposed (for example, Japanese Patent Application Laid-Open No. 57-43132) which is wound up at a high temperature and subjected to self-annealing with the heat retained by the steel strip.

Moreover, the technique (for example, Unexamined-Japanese-Patent No. 3-211258) which improves a magnetic characteristic is also proposed by generating secondary recrystallization and coarse grains before cold rolling. The secondary recrystallization is realized by performing annealing on the hot rolled sheet subjected to cold rolling under light pressure, after reducing the carbon amount than the emphasis property disclosed in Japanese Patent Publication No. 45-22211.

Further, Japanese Laid-Open Patent Publication No. 9-125145 anneals a hot rolled sheet containing 0.0025% by weight or less of carbon with a low concentration of impurity components at an A _c3 or more point, whereby γ → α transformation in subsequent cooling occurs. The technique which suppresses refinement and maintains the hot-rolled sheet particle size coarse is proposed.

However, in recent years, a material having a higher magnetic flux density has been requested from the strong demand for high efficiency of the motor as described above. In addition, if an extra process such as low pressure reduction of the hot rolled steel sheet is required, manufacturing cost increases.

The present invention was developed in view of the above-described fact, and an object of the present invention is to provide an advantageous method for producing a non-oriented electrical steel sheet having high magnetic flux density and low iron loss as compared with the conventional one, and having excellent magnetic properties.

As a result of earnestly examining in order to solve the said subject, the inventors acquired the knowledge described below.

Conventionally, the smaller the amount of C in steel, the better. However, according to studies by the inventors and the like, rather than increasing the amount of C in the steel, hot-rolled sheet annealing of steel is carried out at the austenite region of A _c3 or more point, and the structure after the hot-rolled sheet annealing is fine in cementite. It was found that it is advantageous to improve magnetic properties by using a highly dispersed tissue.

Also,

When P, S and Se in steel are regulated in an appropriate range, stable decarburization annealing is possible, and the aging deterioration of iron loss is effectively suppressed.

The magnetic flux density is further improved by combining the control of the cooling rate in a predetermined temperature range after hot rolling or annealing.

And so forth.

This invention is based on said knowledge.

That is, the summary structure of this invention is as follows.

1. In mass%, C: 0.01 to 0.2%, Si: 3% or less, Mn: 0.05 to 3.0%, Al: 1% or less, and N: 0.005% or less, further,

The following condition (1);

(1) P: 0.2% or less, and S: 0.01% or less,

Or the following condition (2);

(2) Regarding the amounts of P, S, and Se expressed in mass%, at least one of P + 100 × S + 300 × Se ≦ 0.5 (but at least one of P, S, and Se may be free) The remainder is then hot-rolled to a steel having a composition of Fe and unavoidable impurities, hot-rolled sheet annealing at a temperature range of A _c3 or higher, followed by rolling to the final sheet thickness, followed by decarburization annealing and finish annealing. A method for producing a non-oriented electrical steel sheet, which has excellent magnetic properties.

2. Said steel material satisfy | fills said condition (1), The manufacturing method of the non-oriented electrical steel sheet excellent in the magnetic property of said 1 characterized by the above-mentioned.

3. Said steel material satisfy | fills said condition (2), The manufacturing method of the non-oriented electrical steel sheet excellent in the magnetic property of said 1 characterized by the above-mentioned.

4. As for the said steel materials, Sb: 0.005 to 0.05%, Sn: 0.005 to 0.1%, Ni: 0.1 to 5%,

At least one selected from the group consisting of Cr: 0.5 to 5%, Co: 0.1 to 10%, and Cu: 0.01 to 1% is contained, and the magnetic properties according to any one of the above 1 to 3 are Excellent method for producing non-oriented electrical steel sheet.

5. At least one pass of the said rolling after hot-rolled sheet annealing is made the warm rolling of the temperature range of 70-400 degreeC, The manufacturing method of the non-oriented electrical steel sheet in any one of said 1-4 characterized by the above-mentioned.

6. After the said hot-rolled sheet annealing, the temperature range of at least 800-500 degreeC is cooled at an average cooling rate of 1 degree-C / s or more, The manufacturing method of the non-oriented electrical steel sheet in any one of said 1-5 characterized by the above-mentioned. .

7. Said decarburization annealing is performed on the conditions of dew point: 10-40 degreeC, annealing temperature: 700-900 degreeC, and annealing time: 30-3600s, The non-directional electron in any one of said 1-6 characterized by the above-mentioned. Method of manufacturing steel sheet. In addition, this method is particularly preferably combined with the above condition (2).

Moreover, about the raw material hot rolled sheet steel which is preferable to apply the method of the said invention, the summary structure of this invention is as follows.

8. In mass%, C: 0.01 to 0.2%, Si: 3% or less, Mn: 0.05 to 3.0%, Al: 1% or less, and N: 0.005% or less, further,

The following condition (1);

(1) P: 0.2% or less, and S: 0.01% or less,

Or the following condition (2);

(2) P + 100 x S + 300 x Se ≤ 0.5 with respect to the amounts of P, S and Se expressed in mass% (however, at least one of P, S, and Se may be additive-free)

The hot rolled steel sheet for a non-oriented electrical steel sheet having excellent magnetic properties, wherein at least one of the components is satisfied and the balance is composed of Fe and unavoidable impurities.

9. Further, Sb: 0.005 to 0.05%, Sn: 0.005 to 0.1%, Ni: 0.1 to 5%, Cr: 0.5 to 5%,

At least 1 sort (s) chosen from the group which consists of Co: 0.1-10% and Cu: 0.01-1% is contained, The raw material hot rolled sheet steel for non-oriented electrical steel sheets excellent in the magnetic property of 8 characterized by the above-mentioned.

10. Hot rolled material for non-oriented electrical steel sheets having excellent magnetic properties, characterized in that it contains 5 to 1000 carbides / μm ² of carbide having a composition of any of 8 or 9 and having an equivalent diameter of 5 nm to 1000 nm. Grater.

11. The hot rolled steel sheet for a non-oriented electrical steel sheet having excellent magnetic properties, having any one of 8 or 9 and having an average grain size of 20 to 200 µm.

12. The composition has any one of 8 or 9, and has an average crystal grain size of 20 to 200 µm, and further contains 5 to 1000 carbides / µm ² having a circular equivalent diameter of 5 nm to 1000 nm. Hot rolled steel sheet for non-oriented electrical steel sheet with excellent magnetic properties.

Especially the said invention of 10-12 can be obtained by performing hot-rolled sheet annealing on conditions suitable for a hot-rolled sheet. In this case, the carbide is substantially cementite.

[Embodiment for Invention]

Hereinafter, the experimental result which led to this invention is demonstrated. In addition, "%" display regarding a component shall mean the mass% unless there is particular notice.

<Experiment-Influence of hot-rolled sheet annealing temperature>

(Experiment 1)

First, in order to investigate the influence of hot-rolled sheet annealing conditions affecting the magnetic flux density, C: 0.02%, Si: 1.0%, Mn: 0.05%, Al: tr (trace), P: 0.05%, S: 0.0010%, N: 0.002% and Se: tr, and the remainder was vacuum-melted the steel which becomes the composition of Fe and an unavoidable impurity, and it hot-rolled and performed hot-rolled sheet annealing of 800-1150 degreeC and 30s. Subsequently, mist cooling was performed after hot-rolled sheet annealing, and the average cooling rate at 800 to 500 ° C. was measured, and the result was 60 ° C./s. Then, it cold-rolled (25 degreeC) to plate | board thickness: 0.5 mm. In addition, the rolling after hot-rolled sheet annealing shall be called final rolling.

Then, decarburization annealing at 850 ° C. and 60 s in an atmosphere of 20vo1% H ₂ -80vol% N ₂ and a dew point: 35 ° C., followed by finishing annealing at 950 ° C. and 10 s in an atmosphere of 25vo1% H ₂ -75vo1% N ₂ was performed. Was done.

In FIG. 1, the result of having investigated about the relationship between a hot-rolled sheet annealing temperature and magnetic flux density is shown. It can be seen from the figure that the magnetic flux density is greatly improved when the hot-rolled sheet annealing temperature is 1040 ° C or higher.

In order to investigate this cause, the structure observation of the steel plate after hot-rolled sheet annealing was performed.

As a result, the material subjected to hot-rolled sheet annealing at a temperature of 1040 ° C. or higher had a structure in which the austenite grain boundary was observed and finely dispersed cementite having a diameter of 5 to 1000 nm in the ferrite was finely dispersed. From the result of this structure observation, it is thought that the structure was austenite at the hot-rolled sheet annealing step of 1040 ° C or higher. Moreover, the distribution density of cementite was 5-1000 piece / micrometer <^2> .

Then, the Ac3 transformation point of this material was investigated by measuring the thermal expansion coefficient in 30 degreeC / s of temperature rising using the Formaster tester. As a result, it was found that the A _c3 point of the present material was 1040 ° C.

From this, the tissue is a hot rolled sheet annealing A _c3 By performing above, it is considered that once the hot rolled sheet is annealed, it becomes an austenite region and fine cementite is precipitated due to a decrease in the solubility amount of C due to the γ → α transformation during cooling.

(Experiment 2)

C: 0.02%, Si: 0.35%, Mn: 0.05%, Al: tr, N: 0.002%, P: 0.05%, S: 0.0020% and Se: tr, with the balance being the composition of Fe and unavoidable impurities The resulting steel was vacuum-melted, hot-rolled, and then hot-rolled annealed at 800 to 1150 ° C. for 30 s, followed by cold rolling (25 ° C.) to a plate thickness of 0.5 mm as final rolling. Subsequently _, decarburization annealing at 800 ° C. and 60 s in an atmosphere of 20vo1% H ₂ -80vo1% N _{2 and a} dew point: 35 ° C. was carried out, followed by finishing annealing at 850 ° C. and 10 s in an atmosphere of 25 vol% H ₂ -75 vol% N ₂ . It was. Moreover, cooling after hot-rolled sheet annealing was mist cooling, and when the average cooling rate in 800-500 degreeC was measured at that time, it was 60 degreeC / s.

2 shows the results of the investigation of the relationship between the hot rolled sheet annealing temperature and the magnetic flux density. From the figure, it turns out that magnetic flux density improves significantly, when hot-rolled sheet annealing temperature is 1000 degreeC or more.

In order to investigate this cause, the structure of the steel plate after hot-rolled sheet annealing was observed. As a result, in the material subjected to hot-rolled sheet annealing at a temperature of 1000 ° C. or higher, the same austenite grain boundary was observed as in the case of Experiment 1, and the structure was made of finely dispersed cementite in ferrite. Therefore, in the hot-rolled sheet annealing step of 1000 ° C or higher, the structure is considered to be austenite. Moreover, the distribution density of cementite was 5-1000 piece / micrometer <^2> (cementite of 5-1000 nm in circular conversion diameter).

Then, A _c3 transformation point of this material was investigated by measuring the thermal expansion rate in 30 degreeC / s of temperature rising using the Formaster tester. As a result, it was found that the A _c3 point of the present material was 1000 ° C.

Therefore, the said organization chart and hot-rolled sheet annealing in the experiment 2 are A _c3 By performing above the point, it becomes possible to become an austenite region at the time of hot-rolled sheet annealing, and to deposit fine cementite by the fall of the solubility amount of C accompanying (gamma)-(alpha) transformation at the time of cooling.

Under the above conditions, the reason why the magnetic flux density was improved by hot-annealing a material containing a relatively large amount of C was not clearly explained, but the presence of the second phase of cementite recrystallized around the cementite. This arises, and it is thought that this forms the aggregate structure suitable for magnetic flux density.

On the other hand, even in the case of performing hot-rolled sheet annealing in the ferrite region, although not as much as the case of the hot-rolled sheet annealing in the austenite region as in the present invention, somewhat cementite is formed. In this case, however, the magnetic flux density does not improve so much. The reason for this is that not only the difference in cementite amount but also the grain size after hot-rolled sheet annealing in the ferrite region is small, so that the deformation zone in the grains during cold rolling is hardly developed. It is considered that the occurrence of {111} azimuth grains, which are not azimuths, increases. In the experiments 1 and 2, the average grain sizes after the γ reverse hot-rolled sheet annealing were 80 µm and 60 µm, respectively.

Moreover, such cementite is removed in the steel after it is once dissolved in the steel by subsequent decarburization annealing.

<Experiment-Influence of Carbon Content>

(Experiment 3)

Next, in order to investigate the appropriate amount of C, the inventors and the like, C: 0.002-0.2%, Si: 1.0%, Mn: 0.2%, Al: 0.0010%, P: 0.05%, S: 0.0010%, N: 0.002 It contains% and Se: tr, and the remainder is vacuum melted steel which is a composition of Fe and unavoidable impurities, followed by hot rolling, annealing at 1150 ° C. and 30 s hot rolled sheet, followed by an average cooling rate between 800 and 500 ° C. After cooling at: 60 ° C / s, cold rolling (25 ° C) or warm rolling (150 ° C) was performed to plate thickness: 0.5 mm as final rolling. From 850 ℃ in an atmosphere of 35 ℃, and the decarburization annealing of 60~1200s, again 25vo1% H ₂ -75vo1% N ₂ atmosphere of: Subsequently, in accordance with the content of _{C, 20vo1% H 2 -80vo1% N} 2, dew point Finish annealing at 950 ° C. for 10 s was performed. C content of the obtained steel plate was 5-35 ppm.

Fig. 3 shows the results of the investigation of the relationship between the amount of C in the hot rolled sheet and the magnetic flux density (symbol: x). In addition, the same figure also shows the irradiation result when rolling at 150 degreeC warm temperature instead of cold rolling after hot-rolled sheet annealing (symbol: 0).

As is clear from the figure, it can be seen that the magnetic flux density is improved when the amount of C is 0.01% or more.

The reason for this is that, when the amount of C is less than 0.01%, even if hot-rolled sheet annealing is performed at the A _c3 transformation point or more, the cementite which is enough to affect the aggregate structure is not precipitated.

Moreover, as shown in the figure, further improvement of the magnetic flux density is achieved by making final rolling into warm rolling instead of cold rolling.

(Experiment 4)

C: 0.002-0.2%, Si: 0.35%, Mn: 0.2%, Al: tr, N: 0.002%, P: 0.05%, S: 0.0020% and Se: tr, the balance being made of Fe and unavoidable impurities After vacuum-melting the steel which becomes a composition and hot-rolling, after performing hot-rolled sheet annealing of 1150 degreeC and 30 s, plate thickness: 0.5 mm by cold rolling (25 degreeC) or warm rolling (150 degreeC) as final rolling, respectively. Rolled up to. Subsequently, depending on the amount of C, 20 vol% H ₂ -80vo1% N ₂ , dew point: decarburization annealing at 800 ° C. and 60 to 1200 s in an atmosphere of 35 ° C., followed by 850 in 25vo1% H ₂ -75vo1% N ₂ atmosphere. Finish annealing at 10 ° C. was carried out. Moreover, the average cooling rate in the 800-500 degreeC area | region in cooling after hot-rolled sheet annealing was 60 degreeC / s. In addition, C content of the obtained steel plate was 5-37 ppm.

The result of having investigated about the amount of C of a hot rolled sheet and the rolling temperature (henceforth a final rolling temperature) after hot-rolled sheet annealing to magnetic flux density is shown in FIG. The same figure shows that magnetic flux density improves when C amount of a hot rolled sheet is 0.01% or more.

Also in Experiment 4, when the amount of C is less than 0.01%, it is considered that even if hot-rolled sheet annealing is performed at the A _c3 transformation point or more, the cementite that affects the aggregate structure does not precipitate.

Also with respect to the final rolling temperature, it can be seen that the magnetic flux density is further improved by performing warm rolling in the same manner as in Experiment 3.

Experiment-Influence of final rolling temperature

(Experiment 5)

Next, the inventors investigated C: 0.02%, Si: 1.1%, Mn: 0.18%, Al: tr, P: 0.05%, S: 0.0010%, N in order to investigate the influence of the warm rolling temperature on the magnetic flux density. : 0.0018% and Se: tr, the remainder being melted in a vacuum to form a steel composition of Fe and unavoidable impurities, followed by hot rolling, annealing at 1150 占 폚 and 30 s hot-rolled sheet, followed by 800 to 500 占 폚. After cooling at an average cooling rate of 60 ° C./s, final rolling was performed at a rolling temperature of 20 to 400 ° C. to a plate thickness of 0.5 mm. Then, 20 vol% H ₂ -80 vol% N ₂ , dew point: 850 ° C., 60 s decarburization annealing in an atmosphere of 35 ° C., and 950 ° C., 10 s finish annealing in an atmosphere of 25vo1% H ₂ -75vo1% N ₂ again. Was done.

In FIG. 5, the result of having investigated about the relationship between a warm rolling temperature and a magnetic flux density is shown. As shown in the same figure, it turns out that magnetic flux density improves significantly by making rolling temperature into 70 degreeC or more.

In this way, the reason why the magnetic flux density is improved by making the final rolling a warm rolling is considered to be that an aggregate structure suitable for magnetic properties has developed by dynamic strain aging at the time of rolling.

(Experiment 6)

C: 0.02%, Si: 0.35%, Mn: 0.18%, Al: tr, N: 0.0018%, P: 0.05%, S: 0.0020% and Se: tr, with the balance being the composition of Fe and unavoidable impurities The steel to be melted was vacuum-melted, and after hot rolling, the hot rolled sheet was annealed at 1150 ° C. for 30 s, and finally rolled at a rolling temperature of 20 to 400 ° C. to a plate thickness of 0.5 mm. Subsequently, decarbonization annealing at 800 ° C. and 60 s in an atmosphere of 20vo1% H ₂ -80vo1% N ₂ and a dew point: 35 ° C. was performed, followed by finishing annealing at 850 ° C. and 10s in an atmosphere of 25vo1% H ₂ -75vol% N ₂ . Was done. Moreover, when cooling after hot-rolled sheet annealing, the average cooling rate in 800-500 degreeC was measured, and it was 60 degreeC / s.

6 shows the results of the investigation regarding the relationship between the final rolling temperature and the magnetic flux density. As shown in the same drawing, it can be seen that, as in the case of Experiment 5, the magnetic flux density is greatly improved by setting the rolling temperature to 70 ° C or higher.

<Experiment-Influence of cooling rate after annealing

(Experiment 7)

Next, in order to investigate the influence of the cooling rate after hot-rolled sheet annealing, C: 0.02%, Si: 1.0%, Mn: 0.18%, P: 0.05%, Al: tr, S: 0.0018%, N: 0.0015% And Se: tr, and the remainder was melted in a vacuum to form steel containing Fe and unavoidable impurities, followed by hot rolling, followed by hot rolled sheet annealing at 1150 ° C. for 30 s.

Subsequently, when cooling after that, in order to change a cooling rate, the cooling rate was largely changed between 100 degreeC / s to 0.1 degreeC / s by using water cooling, oil cooling, air cooling, and a heat insulation cover. Subsequently, the plate thickness as a final rolling: to 0.5㎜ to the cold rolling (25 ℃), 20vo1% H 2 -80vo1% N 2, dew point: 850 to 25vo1 ℃, decarburization annealing in an atmosphere of 35 ℃ 60s, and again Finish annealing was performed at 950 ° C. for 10 s in an atmosphere of% H ₂ -75vo1% N ₂ .

In FIG. 7, the result of having investigated about the relationship between the cooling rate and magnetic flux density after hot-rolled sheet annealing is shown. As is clear from the figure, it can be seen that the magnetic flux density is further improved when the cooling rate is 1 ° C / s or more. Moreover, even if final rolling was made into warm rolling (100 degreeC), it confirmed that the same tendency was obtained.

In order to investigate this cause, cementite was examined by the transmission electron microscope (TEM) observation of the steel plate after hot-rolled sheet annealing, and when cooling rate is less than 1 degree-C / s, the cementite in particle | grains is less than 5 pieces / micrometer <^2> . It was relatively small, and it was found that mainly precipitated at the grain boundary.

On the other hand, the cooling rate is 1 ℃ / s or more, the cementite of 5~1000nm was observed five or more / ㎛ ² in the particles, particularly when more than 50 ℃ / s 100~1000 gae / ㎛ ² densely distributed precipitates Turned out to be.

From the above results, it is considered that the above-described improvement of the magnetic flux density is caused as follows.

That is, when the cooling rate is 1 ° C./s or more, the cementite is densely dispersed in the particles, so that after the cold rolling, dislocations are accumulated around the cementite. In this way, it is considered that a high magnetic flux density is obtained as a result of preferentially recrystallization of the orientation desired for magnetic properties from within the particles.

In addition, even when the cooling rate is less than 1 ° C / s, the magnetic flux density is improved as compared with the conventional steel sheet annealed hot-rolled at less than A _c3 point or steel plate with less C content. This is considered to be because there is some cementite involved in the above phenomenon.

As mentioned above, the cooling rate after preferable hot-rolled sheet annealing was 1 degree-C / s or more. More preferably, it is 50 degreeC / s or more.

Moreover, the temperature range which controls a cooling rate shall be 800 degreeC-500 degreeC. This is a region in which the cementite precipitates in the region of 800 ° C to 500 ° C, and since diffusion of C is relatively fast in this temperature range, C is precipitated at the grain boundary when it is cooled slowly in this region, and cement is precipitated in the particles. This is because the amount of tightness is reduced. That is, it is effective to control-cool the temperature range of 800 to 500 degreeC in order to obtain very high magnetic flux density.

Moreover, such cementite is removed in the steel after it is once dissolved in the steel by subsequent decarburization annealing.

<Experiment-Influence of S, P and Se>

By the way, when a non-oriented electrical steel sheet is used as a core material of a generator or a large motor, since it is used over 10 years or more, it is necessary for a magnetic property not to change with time. As the steel sheet changes over time, C in steel precipitates as cementite during long-term use, and thus there is a magnetic aging in which magnetic wall movement is inhibited and iron loss is increased. Generally as an evaluation of self aging, the aging treatment of 150 degreeC and about 100 h is performed, and the iron loss after an aging treatment is measured and judged.

(Experiment 8)

Then, in order to investigate the aging change of the steel sheet, C: 0.03%, Si: 0.33%, Mn: 0.2%, Al: tr, N = 0.002%, P: 0.11%, Se: tr and S: 0.003% The two kinds of steels of steel grade B made of steel grades A and S: 0.005% were vacuum-melted, and after hot rolling, the hot rolled sheet was annealed at 1150 ° C for 30 s, and the final thickness was 150 ° C up to 0.5 mm. Warm rolling was performed at. Subsequently, decarbonization annealing at 800 ° C. and 60 s in an atmosphere of 20vo1% H ₂ -80vo1% N ₂ and a dew point: 35 ° C., followed by finishing annealing at 850 ° C. and 10 s in an atmosphere of 25vo1% H ₂ -75vo1% N ₂ was performed. Was done. Moreover, the average cooling rate in the 800-500 degreeC area | region in cooling after hot-rolled sheet annealing was 60 degreeC / s.

Thereafter, after the aging treatment was performed at 150 ° C. for 100 h on each of the obtained steel sheets, iron loss was measured. Moreover, the iron loss W15 / ₅₀ before an aging treatment of all the steel plates was 4.4 W / kg. As a result, the iron loss W _15/50 of steel grade A was _4.5 W / kg, _whereas the iron loss W _15/50 of steel grade B deteriorated to _5.4 W / kg.

From this, it turns out that iron loss is remarkably increased by the aging treatment in steel grade B.

As a result of investigating the material structure to investigate the cause, it was found that fine cementite was observed in the steel grade B, and that the aging precipitation of this cementite deteriorated the magnetic properties, and the cementite was precipitated during the aging treatment. Turned out.

Moreover, as a result of the component analysis of the product plate, it was also found that in steel grade A, the amount of C in steel was decarburized to 0.0010%, whereas in steel grade B, the amount of steel in C was 0.007% and it was not sufficiently decarburized.

Thus, the cause which became a decarburization defect with steel with many S contents is considered as follows.

That is, since S is an element that tends to segregate,

S is segregated around the cementite precipitated at the time of hot-rolled sheet annealing, delaying the employment of cementite at the time of decarburization annealing,

In addition, since the surface segregation S suppressed the adsorption of oxygen to the surface of the steel sheet and slowed down the oxidation reaction of C in the steel,

It is thought that decarburization did not proceed sufficiently.

Also in such a state, since the remaining cementite is dissolved in steel by the subsequent high temperature finish annealing, no adverse effect due to decarburization failure is manifested immediately after the finish annealing. However, if it continues to be used for a long time, the dissolved C deteriorates as cementite in the steel, so that the magnetic properties deteriorate.

(Experiment 9)

As a result, segregation elements such as P and Se other than S may also inhibit the decarburization reaction.

Then, the inventors next investigated C, 0.03%, Si: 0.32%, Mn: 0.18%, Al: tr, N: 0.002% in order to investigate the relationship between the amount of S, P and Se and the iron loss after aging treatment. The steel which variously changed S, P, and Se was vacuum-melted, and after hot-rolling, the hot-rolled sheet annealing of 1150 degreeC and 30 s was carried out, and as a final rolling, warm rolling was carried out at 150 degreeC to plate thickness: 0.5 mm. It was. Then, decarburization annealing at 800 ° C. and 60 s in an atmosphere of 20vo1% H ₂ -80vo1% N _{2 and a} dew point: 35 ° C., followed by finishing annealing at 850 ° C. and 10 s in an atmosphere of 25vo1% H ₂ -75vo1% N ₂ was performed. After that, the aging treatment was further performed at 150 ° C. for 100 h, and then the iron loss was measured. The average cooling rate in the 800-500 degreeC area | region in cooling after hot-rolled sheet annealing was 60 degreeC / s.

In FIG. 8, the result of having investigated about the relationship between the amount of S, P, Se (mass%) and iron loss after an aging treatment is shown using (P + 100xS + 300xSe) as a parameter. The coefficient of each element was set according to the segregation ability (for example, the strength of the surface segregation in the heat treatment of a steel plate) obtained from literature and experience.

As shown in the same figure, it turns out that iron loss is falling when the parameter (P + 100xS + 300xSe) is 0.5 or less. The reason for this is considered that by reducing these elements, the solid solution of cementite in the steel during decarburization annealing becomes easy and decarburization proceeds.

<Component of material steel>

Next, the preferable component composition range (mass%) of the steel in this invention is demonstrated.

C: 0.01% to 0.2%

In the present invention, at least 0.01% of C is required in order to finely disperse cementite in ferrite during formation of the hot-rolled sheet to form an aggregate structure suitable for magnetic flux density. Preferably it is 0.012% or more, More preferably, it is 0.015% or more. However, when the amount of C exceeds 0.2%, decarburization requires a long time and causes an unnecessary cost increase, so the upper limit of the amount of C is made 0.2%. If cost is important, the upper limit of the amount of C is preferably 0.1%, more preferably 0.03%.

Si: 3% or less

Si is an effective element for increasing the resistivity of the steel sheet, but when it exceeds 3%, A _c3 Not only annealing exceeding the point becomes difficult, but also the deformation resistance of the hot rolled sheet rises, making cold rolling difficult. For this reason, the upper limit of the amount of Si was made into 3%. The upper limit is preferably 1.6%. Although a minimum does not need to specifically limit, 0.1% or more is preferable and 0.3% or more is more preferable.

Mn: 0.05% to 3.0%

Mn required 0.05% or more of content in order to prevent the redness brittleness at the time of hot rolling, but when it exceeded 3.0%, since it reduced the magnetic flux density, it was made into 0.05 to 3.0%. The upper limit is preferably 1.0%.

Al: 1% or less

Al, like Si, is an effective element for increasing the resistivity. However, when the content exceeds 1%, Al _c3 increases, and it becomes difficult to anneal in the austenite region in hot-rolled sheet annealing, so the upper limit is 1%. It was. In addition, this Al may be omitted (that is, substantially 0%) as needed.

N: 0.005% or less

When N exceeded 0.005%, since the amount of nitride increased and iron loss increased, it was made into 0.005% or less. In addition, although the amount of N in steel may be substantially 0%, industrial reduction limits are about 0.0005%.

P, S, Se

As shown in FIG. 8 mentioned above, when S, P, and Se amount in steel represented by the mass% exceed 0.5 by a parameter (P + 100xS + 300xSe), decarburization does not advance stably, As a result, As a result, iron loss due to self-aging may be increased. Therefore, in applications where the suppression of self aging is important, the amount of S, P, and Se is preferably limited to 0.5 or less by a parameter (P + 100 × S + 300 × Se).

Moreover, although P is a preferable element in order to improve the punchability of a steel plate, when it adds exceeding 0.2%, since a steel plate will embrittle and cold workability will fall, it is unpreferable on industrial production efficiency. Therefore, it is preferable to make content of P into 0.2% or less from a productivity viewpoint. The amount of P in the steel may be substantially 0%, but the industrial reduction limit is about 0.005%.

S may contain the amount whose parameter (P + 100xS + 300xSe) exceeds 0.5 for the use which does not consider magnetic aging. However, when it exceeds 0.01%, since the amount of sulfides, such as MnS, will increase and iron loss will increase, it is made into 0.01% or less. More preferably, it is 0.005% or less or 0.003% or less. The amount of S in the steel may be substantially 0%.

Se may be contained as an impurity, but may be substantially 0%.

As mentioned above, although the basic component was demonstrated, in this invention, Sb, Sn, Ni, Cr, Co, Cu, etc. can be added suitably from a viewpoint of a magnetic characteristic improvement. In particular, Sb and Sn are effective because they are effective by adding a small amount.

The preferable range of addition of these elements is as follows.

Sb: 0.005 to 0.05%, Sn: 0.005 to 0.1%, Ni: 0.1 to 5%, Cr: 0.5 to 5%, Co: 0.1 to 10%, Cu: 0.01 to 1%

<Manufacturing method and material hot rolled plate>

Next, the manufacturing method of the non-oriented electrical steel sheet which concerns on this invention is demonstrated.

As for the non-oriented electrical steel sheet of this invention, if a component and hot-rolled sheet annealing conditions are in the predetermined range, another manufacturing process is not specifically limited, It does not matter with a conventional method.

That is, in order to obtain the steel plate of this invention, the molten steel blown by the converter is degassed, it adjusts to a predetermined component, it is cast continuously, and it hot-rolls. At this time, the hot rolling finish temperature and the coiling temperature at the time of hot rolling need not be specifically defined, and it does not matter on normal conditions.

The non-oriented electrical steel sheet excellent in magnetic characteristics can be obtained by using the obtained hot rolled sheet steel as a raw material (material hot rolled sheet steel), and hot-rolled sheet annealing on appropriate conditions, and providing it to the process after final rolling by a conventional method.

Next, after hot rolling, the hot rolled sheet is annealed. This hot rolled sheet annealing temperature is A _c3 The temperature is higher than the transformation point. This is because, when the hot-rolled sheet annealing temperature is less than the A _c3 transformation point, as shown in FIGS. 1 and 2 described above, a good improvement in magnetic flux density cannot be expected.

In addition, the upper limit of the hot-rolled sheet annealing temperature is not particularly limited, but it is preferable to set it to about 1250 ° C or less because too high a temperature causes a cost increase and the strength of the steel sheet decreases, which makes the plate difficult.

In addition, the hot-rolled sheet annealing time is not particularly limited, but it can be made into a structure before final rolling that is stable by annealing 10 seconds or more. In addition, unnecessarily long annealing causes an increase in manufacturing cost, and therefore, if continuous annealing, it is preferable to be 500 s or less. If box annealing is used, it is preferable to set it as 10 h or less.

Here, after hot-rolled sheet annealing, it is preferable to make the average cooling rate between at least 800-500 degreeC to 1 degreeC / s or more. Here, an average cooling rate shall divide 300 degreeC (namely, 800 degreeC-500 degreeC) by the time required for cooling from 800 degreeC to 500 degreeC. When the control temperature range is higher than 800 ° C, since C is almost dissolved in steel, the effect of improving the magnetic flux density by changing the cooling rate cannot be expected. Since this slows down, even if the cooling rate is changed, the dispersed state of cementite hardly changes.

The average cooling rate is more preferably 50 ° C./s or more. Although it is not necessary to form an upper limit in particular, it is preferable to set it as 1000 degrees C / s or less from a viewpoint of preventing the burden of a cooling installation, and deformation of a steel plate.

The obtained hot rolled sheet annealing material contained 5-1000 pieces / micrometer ² of cementite of 5-1000 nm size as a result of each said experiment and the other irradiation, and this hot rolled sheet annealing material is used as a raw material (material hot-rolled steel sheet), and By providing to the process after final rolling by the method of, the non-oriented electrical steel sheet excellent in the magnetic characteristic can be obtained.

When the cooling rate after the said hot rolled sheet annealing is less than 1 degree-C / s, cementite becomes content less than 5 piece / micrometer <^2> .

In addition, the number measurement of cementite was performed as follows.

A thin film was produced by hot-rolled annealing plate, and cementite was observed by TEM and SEM. Here, the TEM observed 50000 times with respect to the cementite of 5-100 nm size, and the SEM observed 3000 times with respect to 0.1-1 micrometer of cementite. The size of cementite was calculated | required by the diameter of the circle from which an area becomes the same. In addition, about number distribution, it calculated | required both TEM and SEM by observing 10 visual fields.

Cementite having a size of less than 5 nm and more than 1000 nm was hardly observed in the hot rolled annealing plate. When a considerable number of cementite less than 5 nm or more than 1000 nm is present, it is considered that the number of cementite itself is also likely to fall outside the range of 5 to 1000 particles / µm ² .

In addition, almost no carbide other than cementite was observed in the hot rolled annealing plate produced by the above method. The same effect is expected if other carbides, for example graphite or ε-carbide, satisfy the above distribution (size and number), but cementite is most suitable for achieving the above distribution.

In addition, the crystal grain size of the hot rolled sheet annealing material is preferably to avoid fine grains, specifically, it is preferable to set the average particle diameter of 20㎛ or more, but the grain size can be achieved by the composition of the present invention and the hot rolled sheet annealing conditions. have. The upper limit of the average particle diameter obtained in the said process is about 200 micrometers. The average particle diameter calculated | required the average grain area by the line segment method prescribed | regulated to JIS G 0552, and calculated the particle diameter by circular approximation.

Subsequently, as final rolling, although rolling is carried out to the final plate thickness by cold or warm, especially by rolling at 70-400 degreeC warm, the magnetic flux density can be improved further.

That is, as shown in FIG. 5 and FIG. 6 mentioned above, when rolling temperature becomes 70 degreeC or more, a magnetic flux density will improve significantly. Therefore, the minimum of the temperature at the time of warm rolling was 70 degreeC. More preferably, it is 100 degreeC or more. Moreover, even if a warm rolling temperature exceeds 400 degreeC, although there exists an effect of improving magnetic flux density, it raises a cost unnecessarily, and the upper limit of the temperature at the time of warm rolling was 400 degreeC.

In addition, although the warm rolling may be performed in the whole pass of the final rolling, when it applied to at least one 1 pass of the final rolling, it confirmed that an effect appeared. Therefore, what is necessary is just to make it the said warm rolling conditions in at least one path | pass in the vicinity of a final path using process heat_generation | fever.

Thereafter, decarburization annealing is performed according to the amount of C in the steel, followed by finish annealing to obtain a predetermined magnetic property to obtain a product. In the case of the anti-magnetic aging material, the decarburization annealing is preferably appropriately selected so that the amount of C in the steel in the non-oriented electrical steel sheet after the finish annealing is 0.0050% or less, preferably 0.0030% or less. The reduction limit of the amount of industrial C is about 0.0001%.

Specific preferable conditions of decarburization annealing in the case of a magnetic resistant material are annealing temperature: 700-900 degreeC, annealing time: 30-3600 s, dew point: 10-40 degreeC.

If the decarburization annealing temperature is lower than 700 ° C, decarburization is insufficient. In addition, if it exceeds 900 ° C, strict atmosphere control or the like is necessary in order to avoid an increase in iron loss due to the progress of internal oxidation, resulting in poor efficiency.

In addition, when the decarburization annealing time is less than 30 s, decarburization is insufficient, and when the decarburization annealing time is less than 3s, useless cost increases. However, in the factory of the facility structure where the box annealing apparatus is suitable, decarburization annealing exceeding 3600 s may be performed. As for the processing time in this case, 10 h or less is preferable for cost.

In addition, when dew point is less than 10 degreeC, decarburization becomes inadequate, and when it exceeds 40 degreeC, suppression of internal oxidation becomes a subject.

The finish annealing may be performed under annealing conditions (annealing temperature and time) at which normal recrystallization proceeds. Finish annealing is usually performed by continuous annealing from the viewpoint of cost, but does not prevent the box annealing due to the circumstances of the equipment.

EXAMPLE

(Example 1)

The steel which becomes the component composition shown in Table 1 was melted by converter blow and degassing treatment, and after continuous casting, the slab obtained was heated at 1200 degreeC for 1 h, and then hot-rolled to plate thickness: 2.6 mm. The hot rolling finish temperature was 830 degreeC, and the winding temperature was 610 degreeC.

Subsequently, after hot-rolled sheet annealing on the conditions shown in Table 2, after final rolling in cold (25 degreeC) or warm (50-350 degreeC) to plate | board thickness: 0.5 mm, decarburization annealing and finish annealing are performed, and it is non-oriented It was set as the electronic steel plate. The value of the parameter (P + 100xS + 300xSe) is 0.5 or less except No.44 (S excess content material).

Table 2 shows the results of the investigation of the magnetic properties of the thus obtained electrical steel sheet.

In addition, the magnetic measurement was performed using the 25 cm Epstein test piece. In addition, A _{c3 in a} table | surface The point was calculated | required by measuring the thermal expansion coefficient at the time of heating a sample at 30 degree-C / s by the former starter tester.

After the hot-rolled sheet annealing, the crystal grain size and the size and number of cementite were examined by the above-described method.

As is clear from Table 1 and Table 2, all of the invention examples in which the steel component and the hot-rolled sheet annealing conditions are controlled in the appropriate range of the present invention have both high magnetic flux densities and low iron losses, and especially hot rolling as the final rolling. In the case of the use, excellent magnetic properties were obtained.

On the other hand, in the comparative example in which one or both of the steel component and the hot-rolled sheet annealing condition deviated from the proper range of the present invention, at least one of magnetic flux density and iron loss is not sufficient, and it is inferior to the invention example. Only characteristics were obtained.

In addition, in the invention example, the average crystal grain size of the hot-rolled annealing plate was in the range of 100-1000 particles / µm ^{2 in} the range of 20 to 200 µm and the number of cementite having a circular equivalent diameter of 5 nm to 1000 nm. On the other hand, in Comparative Examples, for example, Nos. 1 to 5, the number of cementite was 0.3 pieces / µm ² or less, and in Nos. 6 to 8, the average grain size was about 10 to 15 µm.

(Example 2)

After performing hot rolling to the steel which becomes a component composition shown in Table 3 on the conditions similar to Example 1, and after hot-rolled sheet annealing on the conditions shown in Table 4, plate | board thickness: Cold (25 degreeC) or warm (up to 0.5 mm) After final rolling at 50 to 350 ° C., decarburization annealing and finish annealing were performed to obtain a non-oriented electrical steel sheet. The value of the parameter (P + 100xS + 300xSe) was 0.21.

Magnetic properties and A _c3 of the electrical steel sheet thus obtained The result of having investigated similarly to Example 1 about a point is written together in Table 4.

As is clear from Table 3 and Table 4, all the invention examples in which the steel component and the hot-rolled sheet annealing conditions are controlled in the appropriate range of the present invention have both high magnetic flux densities and low iron losses, and particularly, hot rolling as the final rolling. When used or when the cooling rate after hot-rolled sheet annealing was made into the suitable conditions of this invention, the outstanding magnetic characteristic was acquired.

On the other hand, all of the comparative examples (herein, comparative examples relating to cooling conditions) in which the cooling rate after hot-rolled sheet annealing deviates from suitable conditions are at least one of magnetic flux density and iron loss. Only suitable magnetic properties were obtained.

The number of cementite having a reduced equivalent diameter of 5 nm to 1000 nm in the symbols C to G, I and J is in the range of 5 to 1000 pieces / µm ² , and particularly in the symbols FmG and J, 100 to 1000 pieces. It was in the range of / micrometer <^2> . In addition, in symbols A, B, and H, it was about 0.5-2 piece / micrometer <^2> . The average grain size of the hot rolled annealing plate was all in the range of 20 to 200 µm.

(Example 3)

After performing hot rolling on the steel which becomes a component composition shown in Table 5 on the conditions similar to Example 1, and after hot-rolled sheet annealing on the conditions shown in Table 6, plate | board thickness: Cold (25 degreeC) or warm (up to 0.5 mm) After the final rolling at 50 to 350 ° C.), decarburization annealing and finish annealing were carried out under the conditions shown in Table 6 to obtain a non-oriented electrical steel sheet. Moreover, the average cooling rate in the 800-500 degreeC area | region in cooling after hot-rolled sheet annealing was 60 degreeC / s.

Magnetic properties and A _c3 of the electrical steel sheet thus obtained The result of having investigated similarly to Example 1 about a point is written together in Table 6. Moreover, after the aging treatment at 150 ° C. and 100 h after the magnetic measurement, the magnetic measurement was performed again. The obtained measurement result is written together in Table 6.

As is clear from Table 6, in the invention examples in which the steel component and the hot-rolled sheet annealing conditions are controlled in the appropriate range of the present invention, both high magnetic flux density and low iron loss are obtained together, in particular, when warm rolling is used as the final rolling. Excellent magnetic properties were obtained.

On the other hand, in the comparative example in which one or both of the steel component and the hot-rolled sheet annealing condition deviated from the proper range of the present invention, at least one of magnetic flux density and iron loss was not sufficient, and compared with the invention example, Only characteristics were obtained.

In addition, in the invention example, the number of cementite whose average crystal grain diameter of the hot-rolled annealing plate was 20-200 micrometers, and the conversion diameter was 5 nm-1000 nm was in the range of 100-1000 piece / micrometer <^2> .

According to the present invention, a non-oriented electrical steel sheet having a high magnetic flux density and low iron loss can be obtained by forming a structure in which cementite is finely dispersed in ferrite in the hot-rolled sheet annealing step.

Therefore, by using the steel plate obtained by this invention, it contributes greatly to the high efficiency of the high efficiency induction motor and EI core, for example.

Claims (20)

In mass%, C: 0.01% to 0.2%, Si: 3% or less, Mn: 0.05 to 3.0%, Al: 1% or less, and N: 0.005% or less It contains and satisfy | fills the following conditions; P: 0.2% or less, and S: 0.01% or less; The remainder is non-oriented, which hot-rolls steel, which is a composition of Fe and unavoidable impurities, performs hot-rolled sheet annealing at a temperature range of A _c3 or higher, and then rolls to a final sheet thickness, followed by decarburization annealing and finish annealing. Method for manufacturing electronic steel sheet. In mass%, C: 0.01% to 0.2%, Si: 3% or less, Mn: 0.05 to 3.0%, Al: 1% or less, and N: 0.005% or less It contains and satisfy | fills the following conditions; With respect to the amounts of P, S and Se expressed in mass%, P + 100 × S + 300 × Se ≦ 0.5, but at least one of P, S and Se may be free of addition; The remainder is non-oriented, which hot-rolls steel, which is a composition of Fe and unavoidable impurities, performs hot-rolled sheet annealing at a temperature range of A _c3 or higher, and then rolls to a final sheet thickness, followed by decarburization annealing and finish annealing. Method for manufacturing electronic steel sheet. In mass%, C: 0.01% to 0.2%, Si: 3% or less, Mn: 0.05 to 3.0%, Al: 1% or less, and N: 0.005% or less Containing and satisfying the following conditions (1) and (2); (1) P: 0.2% or less, and S: 0.01% or less, (2) P + 100 x S + 300 x Se ≤ 0.5, but at least any one of P, S and Se may be free of the amounts of P, S and Se expressed in mass%; The remainder is non-oriented, which hot-rolls steel, which is a composition of Fe and unavoidable impurities, performs hot-rolled sheet annealing at a temperature range of A _c3 or higher, and then rolls to a final sheet thickness, followed by decarburization annealing and finish annealing. Method for manufacturing electronic steel sheet. The method of claim 1, wherein the steel is, Sb: 0.005 to 0.05%, Sn: 0.005 to 0.1%, Ni: 0.1 to 5%, Cr: 0.5 to 5%, Co: 0.1 to 10%, Cu: 0.01 to 1% The manufacturing method of the non-oriented electrical steel sheet containing at least 1 sort (s) chosen from the group which consists of these. The method of claim 2, wherein the steel is further, At least one selected from the group consisting of Sb: 0.005 to 0.05%, Sn: 0.005 to 0.1%, Ni: 0.1 to 5%, Cr: 0.5 to 5%, Co: 0.1 to 10%, and Cu: 0.01 to 1% The manufacturing method of the non-oriented electrical steel sheet containing these. The method of claim 3, wherein the steel is, Sb: 0.005 to 0.05%, Sn: 0.005 to 0.1%, Ni: 0.1 to 5%, Cr: 0.5 to 5%, Co: 0.1 to 10%, Cu: 0.01 to 1% The manufacturing method of the non-oriented electrical steel sheet containing at least 1 sort (s) chosen from the group which consists of these. The manufacturing method of the non-oriented electrical steel sheet in any one of Claims 1-6 which makes at least 1 pass | pass of the said rolling after hot-rolled sheet annealing the warm rolling of the temperature range of 70-400 degreeC. The method for producing a non-oriented electrical steel sheet according to any one of claims 1 to 6, wherein after the hot rolled sheet annealing, a temperature range of at least 800 to 500 ° C is cooled at an average cooling rate of 1 ° C / s or more. The manufacturing method of the non-oriented electrical steel sheet of Claim 7 which cools the temperature range of 800-500 degreeC at least at an average cooling rate of 1 degree-C / s after the said hot-rolled sheet annealing. The non-oriented electrical steel sheet according to any one of claims 1 to 6, wherein the decarburization annealing is performed under the conditions of dew point: 10 to 40 ° C, annealing temperature: 700 to 900 ° C, and annealing time: 30 to 3600s. Manufacturing method. The method for producing a non-oriented electrical steel sheet according to claim 7, wherein the decarburization annealing is performed under a dew point of 10 to 40 ° C, annealing temperature of 700 to 900 ° C, and annealing time of 30 to 3600 s. In mass%, C: 0.01% to 0.2%, Si: 3% or less, Mn: 0.05 to 3.0%, Al: 1% or less, N: 0.005% or less The hot rolled steel sheet for a non-oriented electrical steel sheet containing, wherein the following conditions are satisfied, and the remainder is a composition of Fe and unavoidable impurities. P: 0.2% or less, and S: 0.005% or less In mass%, C: 0.01% to 0.2%, Si: 3% or less, Mn: 0.05 to 3.0%, Al: 1% or less, N: 0.005% or less The hot rolled steel sheet for a non-oriented electrical steel sheet containing, wherein the following conditions are satisfied, and the remainder is a composition of Fe and unavoidable impurities. With respect to the amounts of P, S and Se expressed in mass%, P + 100 × S + 300 × Se ≦ 0.5, but at least one of P, S and Se may be free of addition. In mass%, C: 0.01% to 0.2%, Si: 3% or less, Mn: 0.05 to 3.0%, Al: 1% or less, N: 0.005% or less The material hot rolled steel sheet for non-oriented electrical steel sheets containing these, and satisfy | filling the following conditions (1) and conditions (2), and remainder becomes a composition of Fe and an unavoidable impurity. (1) P: 0.2% or less, and S: 0.005% or less, (2) With respect to the amounts of P, S and Se expressed in mass%, P + 100 × S + 300 × Se ≦ 0.5, but at least one of P, S and Se may be free of addition. The method of claim 12, further comprising: Sb: 0.005 to 0.05%, Sn: 0.005 to 0.1%, Ni: 0.1 to 5%, Cr: 0.5 to 5%, Co: 0.1 to 10%, Cu: 0.01 to 1% The raw material hot rolled steel sheet for non-oriented electrical steel sheets containing at least 1 sort (s) chosen from the group which consists of these. The method of claim 13, further comprising: Sb: 0.005 to 0.05%, Sn: 0.005 to 0.1%, Ni: 0.1 to 5%, Cr: 0.5 to 5%, Co: 0.1 to 10%, Cu: 0.01 to 1% The raw material hot rolled steel sheet for non-oriented electrical steel sheets containing at least 1 sort (s) chosen from the group which consists of these. The method of claim 14 further comprising: Sb: 0.005 to 0.05%, Sn: 0.005 to 0.1%, Ni: 0.1 to 5%, Cr: 0.5 to 5%, Co: 0.1 to 10%, Cu: 0.01 to 1% The raw material hot rolled steel sheet for non-oriented electrical steel sheets containing at least 1 sort (s) chosen from the group which consists of these. The raw material hot-rolled steel sheet for non-oriented electrical steel sheets which has a composition as described in any one of Claims 12-17, and contains 5-1000 pieces / micrometer < ² > of carbides whose diameter is 5 nm-1000 nm. The raw material hot-rolled steel sheet for non-oriented electrical steel sheets which has a composition as described in any one of Claims 12-17, and whose average grain size is 20-200 micrometers. Non-aromatic, which has a composition as described in any one of Claims 12-17, and contains 5-1000 pieces / micrometer < ² > of carbides with an average crystal grain diameter of 20-200 micrometers, and 5 to 1000 nm of circular conversion diameters. Material hot rolled steel sheet for electronic steel sheet.

Images