KR20030052207A - Manufacturing Method for Non-Oriented Electrical Steel Sheet having Superior Punchability and Low Core Loss after Stress Relief Annealing - Google Patents

Abstract

PURPOSE: A manufacturing method of non-oriented electrical steel sheet having superior punchability and low core loss after stress relief annealing even without performing hot rolled strip annealing and skin-pass processes is provided. CONSTITUTION: The method comprises a process of hot rolling the steel slab to a thickness of 1.8 to 3.0 mm by reheating a steel slab comprising 0.005 wt.% or less of C, 0.0005 to 0.005 wt.% of S, 0.0005 to 0.005 wt.% of N, 0.1 to 1.5 wt.% of Si, 0.1 to 1.0 wt.% of acid soluble Al, 0.1 to 1.0 wt.% of Mn and a balance of Fe and other impurities at a reheating temperature (T1) represented as in the following relational expression 1 determined by contents of S and N in the temperature range of 1,050 to 1,250 deg.C:£Relational Expression 1|, T1=1,650+1,200/log(X1+X2)±5 deg.C, where T1 is proper reheating temperature, X1 is content of S (wt.%), and X2 is content of N (wt.%); coiling the hot rolled steel sheet at a coiling temperature (T2) represented as in the following relational expression 2 determined by addition quantities of acid soluble Al and Mn in the temperature range of 600 to 800 deg.C:£Relational Expression 2|T2=1,200+1,200/log£(Y1+Y2)/200|±5 deg.C, where T2 is proper coiling temperature, Y1 is content of acid soluble Al (wt.%), and Y2 is content of Mn (wt.%); cold rolling the pickled hot rolled steel sheet to a thickness of 0.2 to 0.65 mm one time after pickling the coiled non-annealed hot rolled steel sheet; and annealing the cold rolled steel sheet at a temperature of 600 to 800 deg.C for 30 to 300 seconds, machining the resulting steel sheet to a required sizes, and stress relief annealing the steel sheet machined to required sizes at a temperature of 700 to 850 deg.C.

Description

Manufacturing Method for Non-Oriented Electrical Steel Sheet having Superior Punchability and Low Core Loss after Stress Relief Annealing}

The present invention relates to a method for manufacturing a non-oriented electrical steel sheet having low iron loss and excellent punchability after stress relief annealing, and more specifically, after stress relief annealing without undergoing hot rolling and annealing (Skin-Pass). It relates to a method for producing a non-oriented electrical steel sheet having a low iron loss and excellent punchability.

Since non-oriented electrical steel has excellent magnetic properties, it is widely used as an iron core material for electric machines such as various motors, small transformers, and ballasts, and is classified into two types. These include semi-process products, which must be subjected to stress relief annealing after demand processing, and fully-process products, which do not require stress relief annealing. The semi-process products are usually shipped in a modified state in the manufacturing process of steelmaking → continuous casting → slab reheating → hot rolling → winding → hot rolled sheet annealing → cold rolling → annealing → skin-pass rolling → insulation coating After purchasing a thin product and processing the product into the desired shape, stress relief annealing must be performed to obtain magnetic properties suitable for the product. On the other hand, pulley process products are shipped from the steelmaking process → continuous casting → slab reheating → hot rolling → winding → hot rolled sheet annealing → cold rolling → final annealing → insulation coating. It has the advantage that it can be used without.

In recent years, the trend of increasing the efficiency and miniaturization of electrical equipment and increasing the desire to reduce the processing cost has increased the desire for products with low iron loss and excellent punchability in electrical steel sheets, which are core materials. It's happening. In general, the iron loss is expressed in W / kg as electrical loss (Watt) per weight (kg) of the iron core, that is, electrical energy loss caused by heat generation at a specific magnetic flux density and frequency. Therefore, the iron core material having a low iron loss is more preferable for manufacturing high-efficiency electric equipment.

The present inventors have proposed a method for producing a non-oriented electrical steel sheet having excellent iron loss characteristics after stress relief annealing containing Si, Al, Mn, Ni, etc. in Korea Patent Application No. 2000-82818 to provide a non-oriented electrical steel sheet having a low iron loss Has been proposed. However, in this prior art, it is necessary to add expensive Ni and a large amount of Si must be added, thereby increasing the manufacturing cost and deteriorating punchability due to an increase in strength and brittleness of the steel sheet. If the punchability is not good, the demand increases the wear and breakage rate of the mold during processing, which causes a problem that the processing cost increases rapidly.

The present invention is to manufacture a non-oriented electrical steel sheet having a low iron loss after the stress relief annealing as described above according to a more simplified method, the addition or addition of Ni and Si, respectively, which is an expensive element during the steelmaking and the cause of the secondary deterioration In the case of pulley process non-oriented electrical steel sheet, the hot rolled sheet annealing process is omitted, or in the case of semi-process non-oriented electrical steel sheet, the hot rolled plate annealing and light rolling process are omitted. At the same time, to provide a method for producing a non-oriented electrical steel sheet with a significant improvement in iron loss after stress relief annealing, an object thereof.

In the method for producing a non-oriented electrical steel sheet having a low iron loss and excellent punchability according to the present invention for achieving the above object, in the manufacturing method of a non-oriented electrical steel sheet,

By weight% C: 0.005% or less, S: 0.0005 ~ 0.005%, N: 0.0005 ~ 0.005%, Si: 0.1 ~ 1.5%, acid soluble Al: 0.1 ~ 1.0%, Mn: 0.1 ~ 1.0%, remaining Fe and others Reheating the steel slab composed of impurity at a reheating temperature (T1) determined by the following relation 1 according to the S and N content in the temperature range of 1050 to 1250 ° C. and hot rolling to a thickness of 1.8 to 3.0 mm,

[Relationship 1]

T1 = 1650 + 1200 / log (X1 + X2) ± 5 ° C

Where T1: Proper reheating temperature, X1: S content (% by weight), X2: N content (% by weight)

Winding the hot rolled sheet at a winding temperature (T2) determined by the following equation 2 by the amount of acid-soluble Al and Mn added in a temperature range of 600 to 800 ° C.,

[Relationship 2]

T2 = 1200 + 1200 / log [(Y1 + Y2) / 200] ± 5 ℃

Where T2: appropriate winding temperature, Y1: acid-soluble Al content (% by weight), Y2: Mn content (% by weight)

After the pickled micro-rolled hot rolled plate is pickled and cold rolled to a thickness of 0.2 to 0.65 mm,

The cold rolled sheet is annealed at a temperature of 600 to 800 ° C. for 30 to 300 seconds and then subjected to stress relief annealing at a temperature of 700 to 850 ° C. after processing.

Hereinafter, the present invention will be described in detail.

In order to solve the above problems of the prior art, the present inventors have found that the addition of Ni during steelmaking greatly improves the punchability by significantly reducing the Si content, and improves the magnetic properties due to the addition of Ni and the addition of Si. The deterioration of the characteristics is processed by the method of reheating the slab at a temperature controlled according to the S and N contents, and at the same time by performing a hot rolled sheet winding at a temperature controlled by the Al and Mn contents, without performing hot roll annealing. The present invention was completed by confirming the fact that an aggregate structure favorable to magnetic properties is developed during the subsequent stress relief annealing. As a result, it is possible to obtain a non-oriented electrical steel sheet having low iron loss characteristics after stress removal annealing while reducing the manufacturing cost and shortening the manufacturing process.

The present invention is largely divided into steel slab composition step, slab reheating step, hot rolling step, hot rolling plate winding step, cold rolling step, annealing step and stress relief annealing step. In this process, in the present invention, in the steel component adjustment step, the slab is reheated at a temperature controlled according to the S and N contents, without adding Ni and adding Si in a smaller amount than the conventional one, and the temperature controlled according to the Al and Mn contents. By hot rolled sheet winding at, it is characterized in that even if the hot rolled sheet annealing is not performed, the punchability is improved not only when the demand is processed but also the grain growth is easy after stress relief annealing. Hereinafter, the operation and effect of the present invention for each process step will be described in detail.

[Steel slab composition stage]

The composition step of the steel slab is usually preceded by steelmaking, molten steel and ingot or continuous casting process. First, in the steelmaking step, the content of C, N, S in the molten steel is controlled low, and an appropriate amount of Si, Al, Mn, etc. is added. Subsequently, the steel slab containing an appropriate amount of components is manufactured by performing a molten steel in the ingot or continuous casting process. The slab steel of the present invention contains C, Mn, S, N, Si, Al, the remaining Fe and other impurities. Among the components, C, N, and S are elements that inhibit grain growth, and Si, acid solubility. Al and Mn are added into the steel for the purpose of lowering iron loss. The reason for composition range limitation is explained in more detail.

· C: 0.005% or less

When C is excessively contained, slabs are formed during the manufacturing of the electrical steel sheet of the present invention, thereby inhibiting grain growth, and also causing magnetic aging during use as an iron core of an electric device. It is preferable to contain in a steel so that it may have a composition of 0.005% or less.

· N: 0.0005 ~ 0.005%

N tends to react with Al to form AlN precipitates during the steel sheet manufacturing process of the present invention to suppress grain growth, so that N is controlled to have a minimum amount as much as possible. However, in the case of the present invention, in order to control less than 0.0005%, the denitrification cost increases during steelmaking, so that N is preferably 0.0005 to 0.005% in consideration of this.

· S: 0.0005 ~ 0.005%

In addition to N, S tends to react with Mn to form MnS, which is a fine precipitate, to suppress grain growth, so that it has a minimum amount as much as possible. However, for the same reason as in the case of N, in the present invention, S is preferably 0.0005 to 0.005%.

· Si: 0.1 ~ 1.5%

In the present invention, when the Si content is less than 0.1%, the specific resistance of the steel is small, which is not preferable because the iron loss characteristics are deteriorated. When the Si content is more than 1.5%, the excellent magnetic flux density is deteriorated and the punchability is deteriorated due to the increase in brittleness. Not good.

, Acid-soluble Al: 0.1 ~ 1.0%

When the acid-soluble Al is less than 0.1%, the specific resistance of the steel is small, the iron loss characteristics are deteriorated, and when it is more than 1.0%, the cold rolling property is deteriorated.

· Mn: 0.1 ~ 1.0

In the case of Mn, less than 0.1% is not preferable because the specific resistance of the steel is small and the iron loss characteristics are deteriorated, and if it is more than 1.0%, the roll load increases and the cold rolling property is deteriorated.

In addition, the steel contains Fe and other unavoidable impurities.

[Slave reheating stage]

The steel slab reheating step is a pretreatment step of the hot rolling step performed after the component composition step. In the slab reheating step, the slab is charged into a heating furnace and reheated. In this case, in order to reduce the roll load during hot rolling in consideration of hot rolling workability, The reheating temperature of should be at least 1050 ℃. On the other hand, when the reheating temperature exceeds 1250 ° C, precipitates harmful to iron loss characteristics, such as AlN and MnS, are re-dissolved and tend to cause excessive generation of fine precipitates after hot rolling. Such fine precipitates are undesirable because they hinder grain growth and deteriorate iron loss characteristics. In addition, when the reheating temperature exceeds 1250 ° C, not only the error rate decreases due to an increase in the oxidation scale during reheating but also a problem that causes surface defects when not removed in a subsequent process. As for the suitable temperature range of reheating, 1050-1250 degreeC is preferable.

On the other hand, a number of experiments, such as the inventors found that the reheating temperature also affects the aggregate structure, the higher the reheating temperature is found to increase the surface strength of the (100), (110) plane, etc., which is advantageous for the magnetic properties It was. Therefore, within the range of suppressing the re-use of AlN, MnS, etc., it was found that the higher the reheating temperature was controlled, the better the magnetic properties. Based on this, the appropriate reheating temperature was obtained by the following Equation 1 by the S and N content. Experiments have concluded that reheating at temperature is desirable.

[Relationship 1]

T1 = 1650 + 1200 / log (X1 + X2) ± 5 ° C

Where T1: Proper reheating temperature, X1: S content (% by weight), X2: N content (% by weight)

If the S and N content is high, it is desirable to lower the reheating temperature in order to prevent the damage caused by re-use of AlN, MnS, etc. On the other hand, if the S and N content is low, even if the reheating temperature is increased, AlN, MnS Since there is no harmful effect due to re-use, it is indicated that it is desirable to raise the reheating temperature as much as possible by increasing the appropriate reheating temperature in order to improve the texture.

[Hot Rolling Step]

The hot rolling step is performed according to a conventional method, in which the finish rolling temperature is affected by the slab reheating temperature, but in order to prevent excessive generation of an oxide layer of the hot rolled sheet, it is preferable to adjust the temperature to 800 to 950 ° C. If the thickness of the hot rolled sheet is less than 1.8 mm, the shape of the hot rolled sheet becomes poor, which is not preferable. If the thickness of the hot rolled sheet exceeds 3.0 mm, a good texture cannot be obtained, and the magnetic flux density deteriorates.

[Hot rolled sheet winding step]

Subsequently, the hot rolled sheet winding is advantageously performed at a high temperature for grain growth, but if it is too high, an excessively oxidized layer is generated in the hot rolled sheet, resulting in poor pickling and causing surface defects. Therefore, in the case of the present invention, the appropriate winding temperature range is 600 ~ 800 ℃. On the other hand, the inventors have found that the coiling temperature also affects the aggregate structure as a result of a number of experiments, the higher the coiling temperature was found to decrease the strength of the (111) plane adverse to the magnetic properties. Therefore, within the limit that the excessive formation of the oxide layer can be suppressed, the higher the coiling temperature is controlled, the better the magnetic properties. Based on this, the appropriate coiling temperature is determined by the following equation (2) by the addition of acid-soluble Al and Mn. It was concluded that winding at a controlled temperature is desirable.

[Relationship 2]

T2 = 1200 + 1200 / log [(Y1 + Y2) / 200] ± 5 ℃

Where T2: appropriate winding temperature, Y1: acid-soluble Al content (% by weight), Y2: Mn content (% by weight)

Explain that the proper winding temperature depends on the acid-soluble Al and Mn content as follows. If the acid-soluble Al and Mn content is large, there is a closed end causing excessive surface oxides on the steel sheet due to excessive generation of an oxide layer that is difficult to remove during pickling such as Al 2 O 3 and MnO. It is desirable to lower the coiling temperature in order to prevent the harmful effects. On the other hand, in the case where the acid-soluble Al and Mn contents are low, the coiling temperature may be increased even when the coiling temperature is increased, and no damage may occur due to excessive generation of Al2O3 and MnO. This is because it is preferable to raise the coiling temperature as much as possible by making the appropriate coiling temperature the upper limit.

After cooling in air in a coil state, or more preferably furnace cooling.

[Cold rolling stage]

· Pickling

It is essential that the hot rolled sheet is only pickled without performing hot rolled sheet annealing. The hot-rolled sheet annealing is not preferable because grain growth is suppressed during stress relief annealing subsequent to the precipitation of fine carbides and the iron loss is degraded. Therefore, in the present invention, not performing the hot rolled sheet annealing is essential for improving the magnetic properties as well as the advantages of the process shortening.

Subsequently, in the cold rolling step in which the hot rolled sheet is not annealed, but after pickling only the oxide film on the surface of the steel sheet, a cold rolled sheet having a thickness of 0.20 to 0.65 mm is obtained by rolling once to improve rolling productivity.

In the annealing step performed after the above steps, the cold rolled steel sheet is continuously annealed at a temperature of 600 to 800 ° C. for 30 to 300 seconds.

· Cold rolling

The pickled steel plate is then cold rolled. In this case, when rolling at a reduction ratio of less than 64%, rolling productivity is reduced, so it is preferable to roll once at a reduction ratio of 64% or more. At this time, if the cold rolling thickness is less than 0.20 mm, the strength of the (111) plane, which is an unfavorable texture after annealing, is not preferable because the magnetic flux density decreases, and when the thickness exceeds 0.65 mm, the vortex loss increases as the plate thickness increases. This is not good because the iron loss is increased by increasing.

[Annealing Step]

In the annealing step performed according to the above method, in the subsequent annealing step, if the annealing temperature is lower than 600 ° C, the rolled structure remains excessively in the material, so that the demand is difficult to process during processing, and if it is higher than 800 ° C, residual stress in the material It is preferable to anneal at 600-800 ° C. because the disadvantage is that the demand is reduced and the iron loss characteristic improvement rate of the steel sheet is low after the stress relief annealing.

[Stress Removal Annealing Step]

The steel sheet annealed in the annealing step is processed immediately with organic, inorganic and organic / inorganic composite coatings or coated with other insulating coatings without going through the skin-pass rolling step. Punch into shape. After the stress removal annealing step in which the demand for removing the residual stress is a heat treatment process, the residual stress in the steel sheet may remain when the temperature is lower than 700 ℃, if the temperature higher than 850 ℃ may damage the insulating film 700 in the present invention It is preferable to adjust to -850 degreeC temperature. Stress relief annealing is performed under such a temperature for at least 30 minutes in a non-oxidizing atmosphere.

Subsequently, the steel sheet subjected to the annealing step is subjected to stress relief annealing at a temperature of 700 to 850 ° C. in the stress relief annealing step in which demand is finally performed after processing.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the present invention is not limited only to these examples.

Example 1

A steel slab having a thickness of 250 mm having the components shown in Table 1 was prepared, and the steel slab was heated for 3 hours at a reheating temperature as shown in Table 2, and hot-rolled at a finish rolling temperature of 850 ° C. to 2.5 mm. After the hot rolled sheet was made, the hot rolled sheet was wound at a coiling temperature as shown in Table 1 and then cooled in air. The cold rolled hot rolled sheet was subjected to 3 minute hot rolled sheet annealing at 850 ° C only for some comparative materials. Most of the hot rolled sheet was not annealed, but only pickled and removed from the oxide layer, followed by cold rolling to 0.5 mm thickness. Annealed. Cold-rolled sheet annealing was performed at 760 degreeC for 2 minutes in 20% of hydrogen and 80% of nitrogen. The annealing plate is coated with an insulating film of organic / inorganic composite, and then subjected to stress relief annealing under nitrogen atmosphere for 1 hour and 30 minutes at a temperature of 770 ° C. Then, the magnetic properties, grain size and (200), (110), (111) planes The strength was investigated and the results are shown in Table 2 below.

At this time, the _punchability was judged to be inferior when the number of punches required for mold replacement during processing was less than 1 million and good if it was 1.5 to 2.5 _million , and excellent when more than 3 _million . The energy loss consumed by heat when the magnetic flux density of 1.5 Tesla is induced to the iron core. The magnetic flux density, B _50, is induced at an excitation force of 5000 A / m, and the grain size is obtained by grinding the cross section of the stress-annealed specimen. It was then etched with 3% Nital and measured with an Image Analyzer. The surface strength was represented by the aggregate structure strength according to the Horta equation, and as the (200) and (110) surface strengths increased, the (111) surface strength decreased and the magnetic properties improved. Surface defects were determined by visual observation of the surface of the steel sheet after cold rolling.

Steel grade Ingredient (% by weight) C Si Acid Soluble Al Mn S N Invention steel A 0.004 0.1 1.0 0.5 0.003 0.002 B 0.005 1.5 0.1 0.6 0.003 0.003 C 0.002 0.8 0.3 1.0 0.005 0.002 D 0.002 0.7 0.9 0.1 0.004 0.004 E 0.003 0.6 0.6 0.8 0.003 0.005 F 0.005 0.7 0.5 0.7 0.003 0.003 G 0.003 0.5 0.8 0.7 0.002 0.002 H 0.003 0.5 0.8 0.7 0.0005 0.002 I 0.003 0.5 0.8 0.7 0.002 0.0005 J 0.003 0.5 0.8 0.7 0.0005 0.0005 K 0.003 0.5 0.8 0.7 0.005 0.005 L 0.003 0.8 0.1 0.1 0.002 0.002 M 0.003 0.8 0.3 0.2 0.002 0.002 N 0.003 0.4 1.0 1.0 0.002 0.002 Comparative steel A 0.003 0.05 * 0.7 0.6 0.003 0.002 B 0.003 2.0 * 0.7 0.6 0.003 0.002 *: Conditions outside the scope of the present invention

As shown in Table 1 and Table 2, the invention material (1-14) is superior to the punchability compared to the comparative material (1-15), excellent iron loss and magnetic flux density characteristics, and no steel plate surface defects Could know. Specifically, the comparative materials 1, 3, 5 are inferior iron loss characteristics because the components are within the scope of the present invention, but the grain growth is suppressed during stress removal annealing due to the microprecipitation of AlN and MnS as a result of reheating above the proper temperature when reheating the slab Was obtained. Comparative materials 2, 4, and 6 were reheated below the proper temperature, and as a result, they had low (200) and (110) surface strengths, which were favorable for magnetic properties, and thus, excellent iron loss characteristics could not be obtained. In the case of the comparative material (7-12), the component and reheating temperature are within the scope of the present invention, but the hot rolled sheet winding temperature is an example outside the scope of the present invention. Among the comparative materials 7,9 and 11, when the winding temperature was less than the proper temperature, the coils were wound due to the (110) surface strength, which is detrimental to the magnetic properties, and thus excellent iron loss and magnetic flux density were not obtained. In the case where the coiling temperature exceeds the proper temperature, the magnetic properties are excellent, but the excessive oxide layer is formed on the surface of the hot rolled sheet, so that the oxide layer is poorly removed during pickling. Comparative material 13 was not obtained excellent iron loss characteristics when the Si content is less than the scope of the present invention. Comparative Material 14 was inferior in punchability due to excessive Si content and deteriorated magnetic flux density. In Comparative Material 15, when hot-rolled sheet annealing was performed, fine carbides were formed during hot-rolled sheet annealing to suppress grain growth, resulting in inferior iron loss characteristics.

Example 2

Slab composed of C: 0.003%, Si: 0.8%, acid soluble Al: 0.3%, Mn: 0.2%, S: 0.002%, N: 0.002% by weight and the remaining Fe and other impurities are shown in Table 3 below. After reheating for 3 hours at the reheating temperature as shown, it was hot rolled to a thickness of 2.0 mm, wound at a coiling temperature as shown in Table 3, and then cooled in a sealed annealing furnace. The furnace-cooled hot rolled plate was cold pickled to a thickness of 0.5 mm after pickling only without annealing the hot rolled plate. The cold rolled sheet was annealed at 740 ° C. for 2 minutes in an atmosphere of 20% hydrogen and 80% nitrogen. After annealing, the insulation coating of the organic-inorganic mixture was successively coated and then cut. The primary iron loss characteristics were investigated and the results are shown in Table 3 below. In addition, the specimens cut as described above were stress-annealed in an atmosphere of 100% nitrogen for 1.5 hours at a temperature of 770 ° C., and then the final iron loss characteristics were investigated. The results are also shown in Table 3.

Sample Number Reheating Temperature (℃) Winding temperature (℃) Iron loss before stress relief annealing, W15 / 50 (W / kg) Iron loss after stress relief annealing, W15 / 50 (W / kg) Iron loss improvement rate (%) Invention Material 15 1150 740 5.18 2.80 46 Comparative Material 16 1200 * 740 5.75 4.54 * 21 * Comparative Material17 1050 * 600 * 5.46 4.01 * 27 *

As shown in Table 3, in the case of Inventive Material 15, which has the emphasis of the present invention and reheated at an appropriate reheating temperature and wound at an appropriate winding temperature, iron loss after the temperature stress removal annealing was about 46 compared to that before the stress relief annealing. While excellent iron loss characteristics were improved by more than%, stress was removed when the reheating temperature exceeded the invention range (Comparative Material 16) or when the reheating temperature was too low and the winding temperature was below the proper temperature (Comparative Material 17). After annealing, excellent iron loss and iron loss improvement rate were not obtained.

As described above, in the present invention, by adding less Si than usual and not adding Ni, the brittleness and strength of the material can be controlled to ensure excellent punchability during demand processing, depending on the S and N content. Non-oriented electrical steel sheet with low iron loss and high iron loss improvement after stress relief annealing by slab reheating at a controlled temperature and hot rolled sheet winding at a controlled temperature according to the acid-soluble Al and Mn content and no hot rolled sheet annealing. There is an effect that can provide. In addition, according to the present invention, there is no need to add Ni, which is a high-cost element during steelmaking, to reduce manufacturing costs, and to secure excellent magnetic properties without undergoing hot rolling annealing and light rolling, thereby shortening the manufacturing process. It is.

Claims (1)

In the manufacturing method of the non-oriented electrical steel sheet, By weight% C: 0.005% or less, S: 0.0005 ~ 0.005%, N: 0.0005 ~ 0.005%, Si: 0.1 ~ 1.5%, acid soluble Al: 0.1 ~ 1.0%, Mn: 0.1 ~ 1.0%, remaining Fe and others Reheating the steel slab composed of impurity at a reheating temperature (T1) determined by the following relation 1 according to the S and N content in the temperature range of 1050 to 1250 ° C. and hot rolling to a thickness of 1.8 to 3.0 mm, [Relationship 1] T1 = 1650 + 1200 / log (X1 + X2) ± 5 ° C Where T1: Proper reheating temperature, X1: S content (% by weight), X2: N content (% by weight) Winding the hot rolled sheet at a winding temperature (T2) determined by the following equation 2 by the amount of acid-soluble Al and Mn added in a temperature range of 600 to 800 ° C., [Relationship 2] T2 = 1200 + 1200 / log [(Y1 + Y2) / 200] ± 5 ℃ Where T2: appropriate winding temperature, Y1: acid-soluble Al content (% by weight), Y2: Mn content (% by weight) After the pickled micro-rolled hot rolled plate is pickled and cold rolled to a thickness of 0.2 to 0.65 mm, The cold rolled sheet is annealed at a temperature of 600 to 800 ° C. for 30 to 300 seconds, and the demand is followed by a stress relief annealing at a temperature of 700 to 850 ° C. after processing. And manufacturing method of non-oriented electrical steel sheet with low iron loss after stress relief annealing.