WO2017111549A1

WO2017111549A1 - Non-oriented electrical steel sheet and manufacturing method therefor

Info

Publication number: WO2017111549A1
Application number: PCT/KR2016/015226
Authority: WO
Inventors: 배병근; 김용수
Original assignee: 주식회사 포스코
Priority date: 2015-12-23
Filing date: 2016-12-23
Publication date: 2017-06-29
Also published as: CN108474076A; JP7008021B2; US20190017137A1; KR20170075592A; KR102175064B1; JP2019508574A

Abstract

A non-oriented electrical steel sheet according to one embodiment of the present invention comprises 0.005 wt% or less of C (excluding 0 wt%), 1.0-4.0 wt% of Si, 0.15-1.5 wt% of Al, 0.1-1.0 wt% of Mn, 0.2 wt% or less of P (excluding 0 wt%), 0.005 wt% or less of N (excluding 0 wt%), 0.001-0.006 wt% of S, 0.005 wt% or less of Ti (excluding 0 wt%), 0.005 wt% or less of O (excluding 0 wt%), and the remainder being Fe and other inevitable impurities, and satisfies formula 1 below, wherein a mean size of oxides in precipitates is larger than a mean size of non-oxides. Formula (1) (Here, [Si], [Al] and [Mn] respectively indicate the amounts (wt%) of Si, Al, and Mn.)

Description

【Specification】

[Name of invention]

Non-oriented electrical steel sheet and manufacturing method

Technical Field

It relates to a non-oriented electrical steel sheet and a method of manufacturing the same.

[Technology behind the invention] ^'

Non-oriented electrical steel is used as a material for iron cores in rotating equipment such as motors, generators, and stationary equipment such as small transformers, and plays an important role in determining the energy efficiency of electrical equipment. Therefore, the recent demands for energy saving and miniaturization of electrical equipment have been required to improve the efficiency of electrical equipment, which has led to the demand for improvement of characteristics of non-oriented electrical steel sheets. The characteristics of the steel sheet include iron loss and magnetic flux density. The iron loss is small and the magnetic flux density is higher, which is good. When the electric core is added to the core to induce a magnetic field, the lower the iron loss, the less energy is lost. The higher the magnetic flux density, the greater the magnetic field can be induced with the same energy. Therefore, in order to save energy and meet the demand for eco-friendly products, it is necessary to develop a non-oriented electrical steel sheet manufacturing technology with low iron loss and high magnetic flux density.

Among the magnetic properties of non-oriented electrical steel sheet, representative methods for improving iron loss include a method of thinning a large thickness and adding a large resistivity element such as Si and A1. However, the thickness is determined by the characteristics of the product used. The thinner the thickness, the lower the productivity and the higher the cost. The addition of Si, Al, and Mn, which are alloy elements with high resistivity, is a method of reducing iron loss by increasing the electrical resistivity of general materials. There is a contradiction that it cannot be avoided. In addition, when the amount of Si added is _more than _4% , workability is lowered, cold rolling is difficult, productivity is reduced, and as much Al, Mn, etc. are added, the rolling property is lowered, the hardness is increased, and the workability is also decreased. Therefore, there is a need for a technique for improving the magnetic properties while lowering the cost by adding these additive elements most appropriately. On the other hand, the additive elements Fe, SI, Al,. Impurity elements C, S, N, 0, Ti, and the like, which are inevitably added to Mn and the like, are combined to form fine precipitates, thereby inhibiting the growth of grains and impeding the movement of magnetic domains, thereby degrading magnetic properties. Precipitates in these steels include carbides, nitrides, sulfides and oxides. These are shown individually or in combination. These fine compounds are classified into inclusions or precipitates according to their size and cause of formation. Inclusions are larger than 100 nm in size, which does not significantly affect grain growth, and precipitates found to be less than 100 nm inhibit grain growth.

If these precipitates are fine, the amount of the precipitates increases so that it is important to increase the size of the precipitates or to make a composite precipitate of two phases.

[Content of invention]

Problem to be solved

One embodiment of the present invention is to provide a non-oriented electrical steel sheet and a method for manufacturing the same by limiting the amount of alloying elements to be added and to increase the precipitates to facilitate the grain growth and the movement of the magnetic domain during magnetization by improving the magnetic allol.

[Measures of problem]

Non-oriented electrical steel sheet according to an embodiment of the present invention by weight%, C: 0.005% or less (excluding 0%), Si: 1.0 to 4.0%, Al: 0.15 to 1.5%, Mn: 0.1 to 1.0% , P: 0.2% or less (excluding 0% ^' ), N: 0.005% or less (excluding 0%), S: 0.001% to 0.006¾>,: 0.005% or less (excluding 0%) ， 0 : 0.005% or less (excluding 0%) and the balance includes Fe and other unavoidable impurities, satisfy the following formula 1, the average size of the oxide in the precipitate is larger than the average size of the non-oxide.

[Equation 1]

One

-+ 13 X [A1]> 3,7 X ftf l x ¾

1JS ^:

(Wherein [Si], [Al] and [Mn] are represented by Si, Al and Mn, respectively) Content (% by weight).)

The number of oxides in the precipitate may be higher than that of the nonoxide.

Sn and Sb may each further comprise 0.01 to 0.2% by weight further alone or in combination.

Precipitate Increase The number of FeO or precipitates containing FeO may be 4OT or more.

The average grain size may be 50 to 180.

Method for producing a non-oriented electrical steel sheet according to an embodiment of the present invention in weight%, (: 0.005% or less (excluding 0%), Si: 1.0 to 4.0%, Al: 0.15 to 1.5%, Mn: 0.1 to 1.0%, P: 0.¾ or less (excluding 0%), N: 0.005% or less (excluding 0%), S: 0.001% to 0.006¾>,: 0.005¾> or less (0% ), 0: 0.005% or less (excluding OT), and the balance includes Fe and other unavoidable impurities, and hot rolling a slab satisfying the following formula 1 to produce a hot rolled sheet; Winding the hot rolled sheet; annealing and cooling the hot rolled sheet; and rolling the hot rolled annealing sheet to produce a rolled sheet; and finally rolling and rolling the rolled sheet. after nyaeng SIR is maintained for 30 minutes at 600 ^° C or higher in steps to nyaenggak, and the hot-rolled sheet annealing and nyaeng Sir nyaenggak at least 5 seconds at more than 600 ^° C in step Finish-annealing the soft decision nyaeng and nyaeng Sir nyaenggak at least 5 seconds in the above step in 60CTC. 國 1

― + 1.3 X lM]> 3.7 X] X \ Μ? Ι]

1.8

(In formula 1, [Si], [A1] and [Mn] represent Si, A1 and Mn content (weight ¾), respectively.)

The slab may further comprise 0.01 to 0.2% by weight of Sn and Sb, alone or in combination, respectively.

In the step of preparing a hot-rolled sheet, it is possible to heat the slab to less than 1200 ^° C.

In the step of cooling the hot rolled sheet after cooling, the coiling temperature is 600 to 800 ^° C. Can be.

In the step of annealing and engraving the hot rolled sheet, the hot rolled sheet annealing temperature may be 850 to 1,150 ^° C.

In the step of hot rolling the hot-rolled annealing plate to manufacture the hot-rolled sheet, it can be rolled to a thickness of 0.1 to 0.7 kPa.

In the step of hot rolling the hot rolled annealing plate to produce a cold rolled plate, the rolling rolling may include primary rolling, intermediate annealing and secondary rolling.

During annealing in the final annealing and engraving process of the cold rolled sheet, the cracking of the annealing may be between 850 and 1, 100 ^° C.

The average size of the oxide in the precipitate of the prepared electrical steel sheet may be larger than the average size of the non-oxide.

The number of precipitates containing FeO or FeO in the precipitate may be 40% or more.

The average grain size may be 50 to 180 mm 3.

【Effects of the Invention】

The non-oriented electrical steel sheet according to an embodiment of the present invention can improve the magnetism by making the precipitate grow large, thereby facilitating the grain growth and the movement of the magnetic domain during magnetization.

[Specific contents to carry out invention] ^■

Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited to these. These terms are only used to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, one part, component region, layer or section described below may be referred to as a second portion, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for reference only to specific embodiments and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used in the specification, the meaning of "comprising" means certain characteristics, Region, integer, step, action, element, and / or _. It is not intended to specify components but to exclude the presence or addition of other properties, domains, integers, steps, actions, elements and / or components.

When a portion is referred to as "on" or "on" another portion, it may be directly on or on the other portion or may be accompanied by another portion therebetween. In contrast, when a part is mentioned as "directly above" another part, no other part is intervened in between.

Although not defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one having ordinary knowledge in the technical field to which the present invention belongs. Commonly defined terms used are ^' further interpreted as having a meaning consistent with the related technical literature and the presently disclosed contents, and are not interpreted in an ideal or very formal sense unless defined.

Also, unless stated otherwise% means weight% and lppm is

0.00 2 weight).

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Non-oriented electrical steel sheet according to an embodiment of the present invention by weight%, C: 0.005% or less (excluding 0%), Si: 1.0 to 4.0%, Al: 0.15 to 1.5%, Mn: 0.1 to 1.0% , P: 0.2% or less (except 0%), N: 0.005% or less (except 0%), S: 0.001% to 0.006%,: 0.005% or less (except 0¾), 0: 0.005 % Or less (excluding 0%) and the balance include Fe and other unavoidable impurities, satisfy the following formula 1, the average size of the oxide in the precipitate is larger than the average size of the non-oxide.

[Equation 1]

p]

1.8 ^J (However, in formula 1 [Si], [A1] and [Mn] represents the content (% by weight) of Si, A1 and Mn, respectively.)

In one embodiment of the present invention, among the components of the non-oriented electrical steel sheet, in particular, by controlling the components such as Si, Al, Mn precisely, precipitates are generated as large as possible, precipitates do not exist alone, and the complex precipitates This was to be precipitated greatly. In addition, by increasing the average size of the oxide in the extract compared to the average size of the non-oxide to improve the magnetic properties.

The element to be added in one embodiment of the present invention is Si, Mn, Al, P or, if necessary, Sn, Sb, there is Fe of the base material. Other added elements are 0, C, N, S and the like and they need to be managed low. There are nitrides and carbides that make these elements N and C with other elements, oxides made by Al, Mn, Si and Fe, etc., and sulfides made by S, Mn and Cu. These occur alone or in combination. .

In one embodiment of the present invention was intended to coarsen the precipitates, in particular to grow more easily by allowing the precipitates to be precipitated in combination, not alone. Among them, oxides are possible elements without adding additional elements, so that coarsening is easier. As a result, it was confirmed that the magnetic properties of the electrical steel sheet were improved.

In one embodiment of the present invention, the oxide was more than 50% of the total number of precipitates, especially FeO accounted for more than 40% among the oxides. In particular, the effect of the oxide had a great effect on the complex precipitate. These oxides are lowered to zero during steelmaking, but are believed to precipitate after remaining or annealing as oxides in the steel. The sulfides are precipitated in significant amounts upon reheating and hot rolling after slab, which are precipitated as CuS, MnS or their composite precipitates. However, oxides had more complex precipitates of oxides such as FeO, A1 ₂ 0 ₃ , and Si0 ₂ than sulfides, and the bonds of oxides with nitrides and carbides were relatively small.

Oxides of the precipitate generated in one embodiment of the present invention is present alone or combined, and were an average size of 15nm to 70nm, the average yield was observed in 1醒10, 000 per ^{two or} 400, 000 pieces. In addition, the non-oxide in the precipitate alone Alternatively, the average size was 10nm to 50 皿, and the average yield was found to be 5,000 to 200,000 per 1 mm ² .

Thus, by forming the average size of the oxide in the precipitate larger than the average size of the non-oxide can facilitate grain growth, specifically, the average grain size can be 50 to 180. In this case, the grain size refers to grain size measured by an intercept method which is generally used in the field of electrical steel sheet. The reason for component limitation of a non-oriented electrical steel sheet is demonstrated below.

Si: 1.0 to 4.0 wt%

Silicon (Si) is the main element added because it increases the specific resistance of steel and lowers the eddy current loss in iron loss, and is an element that easily forms an oxide. If too much Si is included, low iron loss characteristics are difficult to obtain, and if too much Si is added, rolling may be difficult. Therefore, it can be limited to 1.0 to 4.0% by weight.

Mn: 0.1-1.0 wt%

Manganese (Mn) is added for the purpose of improving iron loss by adding Mn at least 0.1 weight ¾> because it has an effect of lowering iron loss by increasing specific resistance together with Si and A1. However, as the amount of Mn added increases, the saturation magnetic flux density decreases, so the magnetic flux density decreases. In addition, it forms a fine MnS precipitate in combination with S to suppress grain growth and impede the movement of the wall, thereby increasing hysteresis loss among iron losses. 1.0 weight ¾> or less.

A1: 0-15 to 1.5% by weight

Aluminum (A1) is an element that is inevitably added for deoxidation of steel in the steelmaking process, and is mainly added to reduce iron loss, but also serves to reduce saturation magnetic flux density. In addition, when the amount of A1 is excessively small, fine A1N is formed. Grain growth can be suppressed to reduce magnetism. In addition, since too much M causes a decrease in magnetic flux density, the amount of M may be limited to 0.1 to 1.5% by weight. P: 0.2 Weight ¾> or less

Phosphorus (P) decreases iron loss by increasing specific resistance and segregates at grain boundaries to suppress the formation of harmful textures to magnetism and forms an advantageous texture {100}. can do.

C: 0.005% by weight or less

When a large amount of carbon (C) is added, it increases the austenite region, increases the phase transformation period, and increases the iron loss by suppressing the grain growth of ferrite during annealing, and also inferior magnetism by forming carbides in combination with Ti. In the final product-it can be limited to 0.005% by weight or less because the iron loss is increased by self-aging when processed into electrical products.

N: 0.005% by weight or less

Nitrogen (Ν) is preferably an element which is harmful to magnetism such as to form nitrides by strongly bonding with Al, Ti and the like to inhibit grain growth, and therefore it is preferably contained in a small amount, and can be limited to 0.005% by weight or less.

S: 0.001 to 0.006% by weight

Sulfur (S) is an element which forms sulfides such as MnS, CuS, and (Cu, Mn) S, which are detrimental to magnetic properties. Therefore, it is preferable to add sulfur (S) as low as possible. However, if too little is added, rather it is disadvantageous to the formation of texture, the magnetism may be lowered. In addition, when too much is added, the magnetism may be inferior due to the increase of the fine sulfide. Therefore, it can be limited to 0.001 to 0.006% by weight. Ti ： 0.005 wt% or less Titanium (Ti) forms fine carbides and nitrides to suppress grain growth. The more the titanium is added, the more the carbides and nitrides increase the inferior texture, resulting in poor magnetic properties. Therefore, it can be limited to 0.005 weight or less.

0 ： 0.005% by weight or less

Since oxygen (0) produces various oxides and suppresses grain growth, it can be contained as low as possible. Therefore, it can be limited to 0.005% by weight or less. Sn, Sb: 0.01 to 0.2% by weight

Tin (Sn) and antimony (Sb) are segregated elements in the grain boundary to suppress the diffusion of nitrogen through the grain boundary, to suppress the harmful {111} texture and increase the advantageous {100} texture to improve the magnetic properties. In addition, if Sn and Sb are added alone or too much, respectively, grain growth may be suppressed to decrease magnetism and worsen rolling properties. Therefore, in the case of containing Sn or Sb, Sn and Sb may be limited to 0.01 to 0.2% by weight each alone or in combination. In particular, in one embodiment of the present invention by controlling the Si, Mn, A1 in the additive element to satisfy the following formula 1 to have a high Si content without a high Mn content, A1 also contains a considerable amount to suppress A1N, etc. .

[Equation 1]

_^ ^' i- 1.3 X ίΑΙ]> 3,7 χ iM l χ ΓΜι]

1,8

(However, in formula 1 [Si], [A1] and. [Mn] represents the content (wt%) of Si, A1 and Mn, respectively.) A method for manufacturing a non-oriented electrical steel sheet according to an embodiment of the present invention Silver% by weight, C: 0.005% or less (excluding 0%), Si: 1.0 to 4.0%, Al: 0.15 to 1.5%, Mn: 0.1 to 1.0%, P: 0.2% or less (excluding OT) ， N: 0.005% or less (0% S: 0.001% to 0.006%,: 0.005% or less (excluding 0%), 0: 0.005% or less (excluding 0%), and the balance includes Fe and other unavoidable impurities, Manufacturing a hot rolled sheet by heating and heating the slab satisfying 1; Etching the hot rolled sheet after winding; Annealing and engraving the hot rolled sheet; Rolling a hot rolled annealing plate for 4 seconds to produce a cold rolled plate; And final annealing and engraving step of the copper plate, in the step of winding and rolling the hot rolled steel plate to maintain at least 600 ^° C 30 minutes or more to cool, 600 ^° C in the step of annealing and engraving the hot rolled plate 5 seconds or more at the above stage, ^at least 5 seconds at 600 ^° C or more in the final annealing and engraving stage.

In an embodiment of the present invention, after manufacturing the hot rolled sheet, after the hot rolled sheet annealing, and after cooling the molten sheet annealing slowly to cool to have a time to grow the precipitate to improve the magnetic properties.

The following describes the process for each step.

First, the slab is heated and hot rolled to produce a hot rolled sheet. The reason for limiting the addition ratio of each composition is the same as the reason for limiting the non-oriented electrical steel sheet described above. Since the composition of the slab is not substantially changed in the course of hot rolling, hot rolling annealing, hot rolling, final annealing, and the like, the composition of the slab and the composition of the non-oriented electrical steel sheet are substantially the same.

The slabs can be charged into a furnace and heated up to 1,200 ^° C. If the heating temperature is too high, precipitates such as A1N and MnS present in the slab are re-used and then finely precipitated during hot rolling to suppress grain growth and lower magnetism. More specifically, it can be heated ^at 1,050 ^° C to 1,200 ^° C.

The heated slabs are hot rolled to 1.4 kPa to 3 kPa to produce hot rolled plates. When hot rolling, finishing rolling in finishing rolling is finished on ferrite phase, and final rolling reduction is 20% or less to correct plate shape.

Next, roll the hot rolled sheet and roll it. The hot rolled sheet is wound up ^at a temperature of 60CTC to 800 ^° C and indented in air or in a separate furnace. When cooling, the temperature should be maintained at 600 ^° C or higher for at least 30 minutes. Temperature If it is too low or the time is kept short, the precipitates are difficult to grow and may be finely precipitated. More specifically, it may be maintained for 30 minutes to 3 hours at a temperature of 600 to 800 ^° C.

Next, the annealing and annealing the hot rolled sheet. The hot rolled sheet is annealed for magnetic improvement, and the hot rolled sheet annealing temperature is set to 850 to 1,150 ^° C. If the hot rolled sheet annealing temperature is too low, grain growth may be uneven. If the hot-rolled sheet annealing temperature is too high, the grains may grow excessively and the surface defects of the plate may be excessive.

When burning after hot-rolled sheet annealing, the angle is not quenched and maintained at 60CTC or more for 5 seconds. If the temperature is too low or the holding time is too short, the precipitate may be difficult to coarsen and the plate may bend. More specifically, the temperature may be 600 to 800 ^° C., and may be maintained for 5 to 30 seconds.

It can also be pickled after hot-rolled sheet annealing.

Next, the hot rolled annealing plate is rolled by steel to manufacture a hot rolled sheet. Cold rolling is the final rolling thickness from 0.1 隱 to 0.7 隱, and if necessary, cold rolling, intermediate annealing, secondary rolling can be carried out, and the final rolling rate may be in the range of 50 to 95%.

Next, the annealing board is finally annealed and inscribed. Cracking temperature of the soft decision nyaeng annealing when annealing at the annealing step of nyaeng lead plate all is to be 850 to 1, 100 ^° C. Nyaeng the soft decision annealing temperature is below 850 ^° C the growth of crystal grains is insufficient increase in the deleterious set organization {in} texture on the magnetic, and the noo ^° c or more, since the crystal grains are excessively growth can adversely affect the magnetic The cracking temperature of the cold rolled sheet is 850 to 110CTC.

When cooling after annealing the sheet, the corner angle is not abruptly maintained for at least 5 seconds at 600 ^° C or higher. If the temperature is too low or the holding time is short when the angle is fine, fine precipitates may be precipitated alone. More specifically, the cooling temperature may be 600 to 800 ^° C, it can be maintained for 5 to 30 seconds.

Annealed plates are shipped to customers after the insulation coating. The insulating coating may be treated with an organic, inorganic and organic-inorganic composite coating, and may be treated with other insulating coating. Customer is intact after processing steel sheet Can be used. Hereinafter, the present invention will be described in more detail with reference to Examples. However, these examples are only for illustrating the present invention, and the present invention is not limited thereto.

Example 1

Through the residual air melting, the steel ingots prepared as shown in Tables 1 and 2 were prepared, and the inventive steels A1 to A7 in which the weight% amounts of Si, Al and Mn satisfy Equation 1, and Equation 1 below. Unsatisfactory A8 to A12 melted comparative steel.

The molten steels A1 to A7 were prepared in the range of Si, Al, and Mn in the range of the invention, and each ingot was heated at 112 CTC, hot rolled to a thickness of 2.2 kPa, then wound up, and then slowly cooled in air as shown in Table 2 and wound up. The cooled hot rolled steel sheet was annealed in a nitrogen atmosphere for 5 minutes, and was squeezed at a temperature of 600 ^° C. or higher in an atmosphere in which nitrogen and oxygen were common, and quenched by spraying final water. After annealing, the hot rolled sheet was pickled and cold rolled to a thickness of 0.35 kPa. The final annealed sheet was annealed for 2 minutes in a mixed atmosphere of hydrogen 3 OT and nitrogen of 70%. Each corner was changed in an atmosphere of 40% hydrogen and nitrogen. The final annealing plate was examined for the size and quantity of oxides, sulfides, carbides, nitrides and composite precipitates for each specimen, and are summarized in Table 3 by measuring grains and magnetic properties.

As a method for analyzing the size, type, and distribution of precipitates, carbon repl i ca extracted from specimens was observed by TEM and analyzed by EDS. In the TEM observation, the precipitates were analyzed by EDS spectrum with randomly selected areas without bias.

_Iron loss (W _15/50 ) was measured as the average loss (W / kg) in the rolling direction and the vertical direction when the magnetic flux density of 1.5 Tesla was induced at 50 Hz.

The magnetic flux density (B ₅₀ ) was measured by the magnitude of the magnetic flux density (Tes la) when a magnetic field of 5000 A / m was added.

Table 1

Al 0.0025 1.56 0.25 0.42 0.031 0.0024 0.0014 0.0002 0.026 0.012

A2 0.0028 2.64 0.22 0.4 0.036 0.0021 0.0021 0.0015 0.019 0

A3 0.0025 2.82 0.82 0.8 0.045 0.0028 0.0014 0.0017 0 0

A4 0.0022 2.95 0.78 0.62 0.055 0.0021 0.0012 0.0016 0 0

A5 0.0025 2.82 1.3 0.45 0.032 0.0015 0.0025 0.0011 0 0.031

A6 0.0028 2.91 0.32 0.52 0.031 0.0018 0.0021 0.0011 0.024 0.021

A7 0.0022 3.3 0.25 0.4 0.035 0.0032 0.0026 0.0015 0.036 0.015

A8 0.0021 0.52 0.002 0.45 0.031 0.0024 0.0014 0.0002 0.026 0.012

A9 0.0026 1.43 0.25 0.62 0.045 0.0001 0.0015 0.0019 0.025 0.031

A10 0.0023 2.24 0.12 0.72 0.055 0.0032 0.0018 0.0021 0 0.019

All 0.0027 2.51 0.45 0.9 0.023 0.0035 0.0021 0.0021 0.035 0

A12 0.0029 2.96 0.74 1.3 0.019 0.0019 0.0019 0.0025 0.043 0

[Table 2]

Al

X 650 60 1000 12 1050 15 Comparative Steel 3 0

Al

X 650 60 1000 12 1050 15 Comparative Steel 4 1

Al

X 650 60 1000 12 1050 15 Comparative Steel 5 2

[Table 3]

As shown in Tables 1 to 3, A1 to A7 satisfy the composition range and Equation 1 of the electrical steel sheet. It can be confirmed that the larger than, the crystal grains are also well grown, and the iron loss and magnetic flux density is also excellent. On the other hand, A8 to A12 does not satisfy the composition range and formula 1 of the electrical steel sheet, and some can confirm that the size of the oxide in the precipitate is smaller than the size of the non-oxide. Therefore, it can be confirmed that iron loss and magnetic flux density are poor. Example 2

Ingots were prepared as shown in Tables 4 and 5 through vacuum dissolution to dissolve Si, Al, and Mn by invented steels A13 to A15 in which the amounts of the weight percent of Eq.

Each ingot is heated at 1120 ^° C, hot rolled to a thickness of 2.2 隱, wound up and wound up in the air as shown in Table 5, and the hot rolled steel sheet is annealed in a nitrogen atmosphere for 5 minutes, and nitrogen and oxygen are common. Sudden at a temperature of 600 ^° C. or more in the atmosphere was sprinkled with the final water. The annealed hot rolled sheet was pickled and rolled to a thickness of 0.35 mm, and the final annealed of the cold rolled sheet was annealed for 2 minutes in a mixed atmosphere of 30% hydrogen and 70% nitrogen. The cooling zone was different in an atmosphere of 40% hydrogen and nitrogen. The final annealing plate was examined for the size and quantity of oxides, sulfides, carbides, nitrides, and composite precipitates for each specimen, and are summarized in Table 6 by measuring grains and magnetic properties. TABLE 4

[Table 5]

Equation 1 Έ3τ s ᅳ I over 11

o— i ᅡ S □ j

o— 1 ο ΐ2 ιι_ι! μ ΤΓ gj i

ο— 1

¾ of sick o o satisfy Temperature Time 600 ° C or higher than 600 ° C Remarks annealing temperature ⁽⁰ C) annealing temperature (° C)

Whether (° C) (minutes) hold (seconds) hold time

A13 0 650 50 950. 12 980 10 Inventive Steel 8 A13 0 650 50 800 2 980 2 Comparative steel 6

A14 0 620 80 1020 10 1020 11 Steel of invention 9

A14 0 620 80 1020 2 1020 11 Comparative Steel 7

A14 0 620 1 1020 2 900 2 Comparative steel 8

A14 0 520 80 1020 2. 1020 2 Comparative Steel 9

A15 0 650 30 1020 15 1020 12 Inventive Steel 10

A15 0 650 1 1020 2 1020 2 Comparative Steel 10

A15 0 650 30 1020 2 1020 2 Comparative steel 11

Table 6

In the precipitate

7 = 1 ᄌ BI ^■ Largest precipitate

Magnetic flux

Steel oxide nonoxide

Size FeO ratio ((W _15/50) Fig. (B ₅₀₎ Remarks Division

Size rain size rain

(μιη)%) W / kg Tesla

(nm) (%) (nm) (%)

A1

75 47 68 52 35 32 2.81 1.75 Inventive Steel 8

3

A1

45 30 41 35 38 59 3.52 1.72 Comparative Steel 6 3

A1

78 52 65 45 46 35 2.23 1.71 Inventive Steel 9 4

A1

60 28 38 38 35 ₆₂ 2.52 1.68 Comparative Steel 74

A1

40 31 35 35 35 65 2.43 1.67 Comparative Steel 8 4

A1

60 28 36 32 36 64 2.61 1.68 Comparative Steel 9 4

A1

120 65 80 57 38 20 2.11 1.71 Inventive Steel 10 5

A1

72 25 45 35 33 55 2.43 1.65 Comparative Steel 10 5 Al

67 21 42 36 33 58 2.64 1.63 Comparative Steel 11

5 As shown in Tables 4 to 6, in comparison with the comparative steels, the inventive steel gave sufficient cooling time after winding, and after forming annealing hot-rolled and annealed plates, the oxides including FeO oxides were formed ^{at a} temperature of 600 ^° C or more. It was confirmed that the crystal grains grew well and the magnetism was excellent.

On the other hand, comparative steel 6 had a low degree of hot-rolled sheet annealing, short holding time over 600 ^° C, and small amount of oxide in precipitate. After the annealing of the hot-rolled steel sheet at 7 ° C, the angle of shortening was short, so the oxides in the precipitates were relatively small in size compared to the non-oxides _. The yield was low and the ratio of FeO oxide was low as 40% or less. Comparative steel 8 was shortened by the angle of winding after winding, and was short after 60CTC after hot-rolled sheet annealing. Low magnetic flux density Although the 9 ° C of the comparable steel is satisfactory, the coiling temperature is low, and the annealing time during cooling after the annealing of the hot rolled sheet is short. We can see that it is poor. Comparative steel 10 was rapidly wound up into the water and wound together with comparative steel 11 to shorten the time after annealing the hot rolled and rolled sheets. have. The present invention is not limited to the embodiments can be manufactured in a variety of different forms, those skilled in the art to which the present invention pertains to other specific forms without changing the technical spirit or essential features of the present invention It will be appreciated that it may be practiced. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims

【Claims】【Claim 1】 By weight %, C: 0.005% or less (excluding 0%), Si: 1.0 to 4.OT, Al: 0.15 to 1.5%, Mn: 0.1 to 1.0%, ?: 0 . (0¾ or less is excluded), Ν:0.005% or less (0% is excluded), S: 0.001% to 0.006%, Ti:0.005% or less (0% is excluded), 0:0.005% or less (0 % is excluded) and the remainder contains Fe and other inevitable impurities, satisfies Equation 1 below, and the average size of oxides in precipitates is larger than the average size of non-oxides.

[Equation 1]

+ 1.3

(However, in Formula 1, [Si], [Al], and [Mn] represent the contents (weight ¾>) of Si, Al, and Mn, respectively.)

【Claim 2】

In clause U,

A non-oriented electrical steel sheet in which oxides among the precipitates are greater in number than non-oxides.

【Claim 3】

In clause 1,

Non-oriented electrical steel sheet further containing 0.01 to 0.2% by weight of Sn and Sb, either alone or in combination.

[Claim 4]

In clause 1,

Non-oriented electrical steel sheet with more than 40% of FeO or FeO-containing precipitates.

【Claim 5】

In clause 1,

Non-oriented electrical steel sheet with an average grain size of 50 to 180卿.

【Claim 6】

In weight %, (::0.005% or less (excluding 0%), Si: 1.0 to 4.0%, Α1:0·15 to 1.5%, Μη: 0.1 to 1.0%, Ρ: 0.2% or less (0% is excluded), 0.005¾> or less (0¾) is excluded), S: 0.001% to 0.006%, Ti: 0.005¾> or less (0% is excluded), 0: 0.005% or less (0% is excluded) and the remainder contains Fe and other inevitable impurities, heating a slab that satisfies the following equation 1 and then hot rolling to produce a hot-rolled sheet;

A step of winding the hot-rolled sheet and then cutting it;

Annealing and cutting the hot-rolled sheet;

Manufacturing a nap-annealed plate by rolling a hot-rolled annealed plate; and

It includes the step of final annealing and sharpening the cold rolled sheet,

In the step of cooling after winding the hot-rolled sheet, it is cooled by maintaining it at 600 ^° C or higher for more than 30 minutes,

In the step of annealing and flattening the hot-rolled sheet, annealing is performed at 600 ^° C or higher for more than 5 seconds,

A method of manufacturing a non-oriented electrical steel sheet in which the nap sheet is annealed at 60 CTC or more for more than 5 seconds in the final annealing and cooling step.

[Equation 1]

pi)

+ 1.3

【Claim 7】

In clause 6,

A method of manufacturing a non-oriented electrical steel sheet in which the slab further contains 0.01 to 0.2% of Sn and Sb alone or in combination.

【Claim 8】

In clause 6,

In the step of manufacturing the hot-rolled sheet, a method of manufacturing a non-oriented electrical steel sheet by heating the slab to 1200 ^° C or less.

【Claim 9】

In paragraph 16,

A method of manufacturing a non-oriented electrical steel sheet in which the coiling temperature is 600 to 800 ^° C in the step of coiling the hot rolled sheet.

【Claim 10】

In paragraph 16,

In the step of annealing and annealing the hot ^- rolled sheet, the annealing temperature of the hot-rolled sheet is 850 to 1, 150 ^° C. Non-oriented electrical steel sheet and manufacturing method.

【Claim 11】

In clause 6,

In the step of manufacturing a nap sheet by cold rolling the hot-rolled annealed ¾, a method of manufacturing a non-oriented electrical steel sheet in which the nap is rolled to a thickness of 0.1 to 07匪.

【Claim 12】

In clause 6,

In the step of producing a nub-rolled sheet by rolling the hot-rolled annealed sheet, the nub-rolling is a method of manufacturing a non-oriented electrical steel sheet including primary nub-rolling, intermediate annealing, and secondary nub-rolling.

[Claim 13]

In clause 6,

When annealing in the final annealing and flattening step of the nub soft plate, the cracking temperature of the annealing is 850 to 1, 10 (TC). Method of manufacturing a non-oriented electrical steel sheet.

【Claim 14】 ^'

In clause 6,

Method for manufacturing non-oriented electrical steel sheets in which the average size of oxides among the precipitates of manufactured electrical steel sheets is larger than the average size of non-oxides /

【Claim 15】

In clause 14,

A method of manufacturing a non-oriented electrical steel sheet in which oxides among the precipitates are greater in number than non-oxides.

【Claim 16】 In clause 14,

Method for manufacturing non-oriented electrical steel sheets in which the number of precipitates containing FeO or FeO is 40% or more.

[Claim 17]

According to clause 14,

A method of manufacturing a non-oriented electrical steel sheet with an average grain size of 50 to 180卿.