Non-oriented electrical steel sheet and method for manufacturing same

Abstract

A non-oriented electrical steel sheet according to an embodiment of the present invention contains, in wt%, 1.5-5.0% of Si, 0.1-2.0% of Al, and 0.1-2.0% of Mn, with the remainder comprising Fe and inevitable impurities, wherein the area fraction of grains within a range of 15° of (111)[341] is 15% or less.

Description

Non-oriented electrical steel sheet and its manufacturing method One embodiment of the present invention relates to a non-oriented electrical steel sheet and a method for manufacturing the same. Specifically, one embodiment of the present invention relates to a non-oriented electrical steel sheet and a method for manufacturing the same, which improves mechanical properties at high temperatures by suppressing the formation of a specific aggregate structure through two annealings including pickling during a hot-rolled sheet annealing process. Non-oriented electrical steel is mainly used in motors that convert electrical energy into mechanical energy, and in this process, excellent magnetic properties of non-oriented electrical steel are required to achieve high efficiency. In particular, as eco-friendly cars driven by motors instead of internal combustion engines have been gaining attention recently, demand for non-oriented electrical steel used as a drive motor core material is increasing, and for this purpose, non-oriented electrical steel with excellent magnetic properties and strength is required. The magnetic properties of non-oriented electrical steel sheets are mainly evaluated by iron loss and magnetic flux density. Iron loss refers to the energy loss that occurs at a specific magnetic flux density and frequency, and magnetic flux density refers to the degree of magnetization obtained under a specific magnetic field. The lower the iron loss, the more energy-efficient the motor can be manufactured under the same conditions, and the higher the magnetic flux density, the more miniaturized the motor or reduced the copper loss. Therefore, using non-oriented electrical steel sheets with low iron loss and high magnetic flux density, a drive motor with excellent efficiency and torque can be manufactured, which can improve the driving range and output of eco-friendly vehicles. The characteristics of non-oriented electrical steel sheets that should be considered also vary depending on the operating conditions of the motor. As a general standard for evaluating the characteristics of non-oriented electrical steel sheets used in motors, W15 / 50, which is the iron loss when a 1.5T magnetic field is applied at a commercial frequency of 50Hz, is widely used. However, in the case of non-oriented electrical steel sheets with a thickness of 0.35mm or less used in eco-friendly vehicle drive motors, magnetic characteristics are often important at low fields of 1.0T or less and high frequencies of 400Hz or higher, so W10 / 400 The properties of non-oriented electrical steel sheets are often evaluated by iron loss. Meanwhile, the characteristics required for eco-friendly vehicle drive motors are to increase the driving distance and increase the top speed. To this end, the low iron loss and high magnetic flux density characteristics of electrical steel sheets are important, but high strength characteristics are also very important. In particular, during high-speed rotation, the temperature of the motor increases to around 200℃, and at this time, the mechanical characteristics deteriorate. Therefore, maintaining the mechanical characteristics at this temperature is important for increasing the motor efficiency. One embodiment of the present invention provides a non-oriented electrical steel sheet and a method for manufacturing the same. Specifically, one embodiment of the present invention provides a non-oriented electrical steel sheet and a method for manufacturing the same, which improves mechanical properties at high temperatures by suppressing the formation of a specific aggregate structure through two annealings including pickling during a hot-rolled sheet annealing process. A non-oriented electrical steel sheet according to one embodiment of the present invention contains Si: 1.5 to 5.0% by weight, Al: 0.1 to 2.0%, Mn: 0.1 to 2.0% by weight, and the remainder includes Fe and inevitable impurities, (111)

[0341] The area fraction of crystal grains within a range of 15° is 15% or less. A non-oriented electrical steel sheet according to one embodiment of the present invention may further include at least one of P: 0.1 wt% or less (excluding 0%), C: 0.005 wt% or less (excluding 0%), S: 0.005 wt% or less (excluding 0%), Ti: 0.005 wt% or less (excluding 0%), and N: 0.005 wt% or less (excluding 0%). A non-oriented electrical steel sheet according to one embodiment of the present invention may further contain 0.005 to 0.200 wt% of each or a combined amount of one or more of Sn, Sb, Bi, Pb, Ge, and As. A non-oriented electrical steel sheet according to one embodiment of the present invention may further include at least one of Cu: 0.005 to 0.2 wt%, Cr: 0.01 to 0.5 wt%, Ni: 0.05 wt% or less (excluding 0%), Zn: 0.01 wt% or less (excluding 0%), and Co: 0.05 wt% or less (excluding 0%). A non-oriented electrical steel sheet according to one embodiment of the present invention may further include at least one of Mo: 0.03 wt% or less (excluding 0%), B: 0.0050 wt% or less (excluding 0%), V: 0.0050 wt% or less (excluding 0%), Ca: 0.0050 wt% or less (excluding 0%), Nb: 0.0050 wt% or less (excluding 0%), Zr: 0.005 wt% or less (excluding 0%), Te: 0.01 wt% or less (excluding 0%), and Mg: 0.0050 wt% or less (excluding 0%). A non-oriented electrical steel sheet according to one embodiment of the present invention may have an average grain size of 100 ㎛ or less. A non-oriented electrical steel sheet according to one embodiment of the present invention can satisfy the following equation 1. [Formula 1] (YS 200℃ ×TS 200℃ ×EL 200℃ ) / ( YS 25℃ ×TS 25℃ ×EL 25℃ ) ≥ 0.60 (YS in Equation 1 200℃ , TS 200℃ and EL 200℃ represents the yield strength, tensile strength and elongation measured at 200℃, respectively. YS 25℃ , TS 25℃ and EL 25℃ ) represent the yield strength, tensile strength and elongation measured at 25℃, respectively. A non-oriented electrical steel sheet according to one embodiment of the present invention can satisfy the following equation 2. [Formula 2] (YS 150℃ ×TS 150℃ ×EL 150℃ ) / (YS 200℃ ×TS 200℃ ×EL 200℃ ) ≥ 1.1 (YS in Equation 2 150℃ , TS 150℃ and EL 150℃ represents the yield strength, tensile strength and elongation measured at 150℃, respectively. YS 200℃ , TS 200℃ and EL 200℃ ) represent the yield strength, tensile strength and elongation measured at 200℃, respectively. A method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention comprises the steps of: hot-rolling a slab containing, in wt%, Si: 1.5 to 5.0%, Al: 0.1 to 2.0%, and Mn: 0.1 to 2.0%, with the remainder being Fe and unavoidable impurities, to manufacture a hot-rolled steel sheet; a cold-rolling pre-annealing step of annealing the hot-rolled steel sheet; a step of cold-rolling the hot-rolled steel sheet to manufacture a cold-rolled sheet; and a cold-rolled sheet annealing step of annealing the cold-rolled sheet. The cold rolling annealing stage includes a first annealing stage, a pickling stage, and a second annealing stage. The slab may further contain at least one of P: 0.1 wt% or less (excluding 0%), C: 0.005 wt% or less (excluding 0%), S: 0.005 wt% or less (excluding 0%), Ti: 0.005 wt% or less (excluding 0%), and N: 0.005 wt% or less (excluding 0%). The slab may further contain 0.005 to 0.200 wt% of each or a combination of one or more of Sn, Sb, Bi, Pb, Ge and As. The slab may further contain at least one of Cu: 0.005 to 0.2 wt%, Cr: 0.01 to 0.5 wt%, Ni: 0.05 wt% or less (excluding 0%), and Zn: 0.01 wt% or less (excluding 0%). The slab may further include at least one of Mo: 0.03 wt% or less (excluding 0%), B: 0.0050 wt% or less (excluding 0%), V: 0.0050 wt% or less (excluding 0%), Ca: 0.0050 wt% or less (excluding 0%), Nb: 0.0050 wt% or less (excluding 0%), Zr: 0.005 wt% or less (excluding 0%), Te: 0.01 wt% or less (excluding 0%), Co: 0.05 wt% or less (excluding 0%), and Mg: 0.0050 wt% or less (excluding 0%). After the step of manufacturing a hot-rolled steel sheet, a pre-cold rolling step of pre-cold rolling the hot-rolled steel sheet may be further included, and the pre-cold rolling annealing step may anneal the pre-cold rolled steel sheet. The first annealing step can be performed at a temperature of 950 to 1050°C. The pickling step can be performed at a temperature of 10 to 100℃. It can be cracked at a temperature of 500 to 700°C in the second annealing stage. After the second annealing step, a pickling step may be further included. The slab further contains Cr: 0.01 to 0.5 wt%, and can be heated to a temperature range of 300 to 800°C prior to the cold rolled sheet annealing step so as to satisfy the following equation 3. [Formula 3] [Cr] × [heating rate] ≥ 50 (In Equation 3, [Cr] is the content of Cr in the slab (weight%), and the heating rate represents the average heating rate of the steel plate (℃ / sec) in the temperature range of 300 to 800℃.) Before the cold rolled sheet annealing step, the temperature range of 300 to 800°C can be increased at a heating rate of 150 to 300°C / s. The cold rolled sheet annealing step can be performed at a soaking temperature of 900 to 1050°C for 60 seconds or less. A non-oriented electrical steel sheet according to one embodiment of the present invention has excellent mechanical strength even at a high temperature of 200°C because the formation of a specific aggregate structure is suppressed. In addition, the steel plate according to one embodiment of the present invention has excellent magnetic flux density and iron loss. Ultimately, the non-oriented electrical steel sheet according to one embodiment of the present invention contributes to the manufacture of eco-friendly automobile motors, high-efficiency home appliance motors, and super premium-grade electric motors. The terms first, second, and third, etc. are used to describe, but are not limited to, various parts, components, regions, layers, and / or sections. These terms are only used to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Thus, a first part, component, region, layer, or section described below may be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms include the plural forms as well, unless the context clearly dictates otherwise. The word "comprising," as used herein, specifies particular features, regions, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components. When a part is referred to as being "on" or "on" another part, it may be directly on or above the other part, or there may be other parts intervening. In contrast, when a part is referred to as being "directly on" another part, there are no other parts intervening. Also, unless otherwise specified, % means weight%, and 1 ppm is 0.0001 weight%. In one embodiment of the present invention, the inclusion of an additional element means including the remainder of iron (Fe) in an amount equivalent to the additional amount of the additional element. Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted as having a meaning consistent with the relevant technical literature and the presently disclosed content, and are not interpreted in an ideal or very formal sense unless defined. Hereinafter, embodiments of the present invention will be described in detail so that those with ordinary skill in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. A non-oriented electrical steel sheet according to one embodiment of the present invention contains, in wt%, Si: 1.5 to 5.0%, Al: 0.1 to 2.0%, Mn: 0.1 to 2.0%, and the remainder includes Fe and inevitable impurities. Below, the reasons for the limitation of the components of non-oriented electrical steel sheets are explained. Si: 1.5 to 5.0 wt% Silicon (Si) increases the resistivity of the material, thereby reducing iron loss, and increases strength through solid solution strengthening. If too little Si is added, the effect of improving high-temperature strength deterioration may be insufficient. If too much Si is added, the hardness of the material may increase, resulting in poor productivity and die-casting properties. Therefore, Si may be included in an amount of 1.5 to 5.0 wt%. More specifically, it may be included in an amount of 2.0 to 4.5 wt%. More specifically, it may be included in an amount of 3.2 to 4.3 wt%. Al: 0.1 to 2.0 wt% Aluminum (Al) increases the resistivity of the material, thereby lowering iron loss, improving rollability, and enhancing workability during cold rolling. If too little Al is added, it may be difficult to obtain the effect of reducing high-frequency iron loss, and the precipitation temperature of AlN may be lowered, causing fine nitrides to be formed, which may reduce magnetism. If too much Al is added, not only may the deterioration of high-temperature strength increase, but also problems may occur in all processes such as steelmaking and continuous casting, which may significantly reduce productivity. Therefore, Al may be included in an amount of 0.1 to 2.0 wt%. More specifically, it may be included in an amount of 0.3 to 1.5 wt%. More specifically, it may be included in an amount of 0.5 to 1.3 wt%. Mn: 0.1 to 2.0 wt% Manganese (Mn) improves iron loss by increasing the resistivity of the material and plays a role in forming sulfides. If too little Mn is added, fine sulfides are formed, causing magnetic deterioration, and if too much Mn is added, deterioration of high-temperature strength may become noticeable. Therefore, Mn may be included in an amount of 0.1 to 2.0 wt%. More specifically, it may be included in an amount of 0.3 to 1.8 wt%. More specifically, it may be included in an amount of 0.5 to 1.5 wt%. In one embodiment of the present invention, the resistivity of the non-oriented electrical steel sheet may be 55 μΩ·cm or more. The resistivity is better the larger the better for reducing eddy current loss in a high-frequency rotating machine, but if it becomes too large, the magnetic flux density may be inferior. In one embodiment of the present invention, the resistivity can be estimated from the equation 13.25+11.3×([Si]+[Al]+[Mn] / 2+[Cu] / 2+[Cr] / 2). In this case, if Cu and Cr are not included, it can be calculated as 0. More specifically, the resistivity can be 60 to 80 μΩ·cm. A non-oriented electrical steel sheet according to one embodiment of the present invention may further include at least one of P: 0.1 wt% or less (excluding 0%), C: 0.005 wt% or less (excluding 0%), S: 0.005 wt% or less (excluding 0%), Ti: 0.005 wt% or less (excluding 0%), and N: 0.005 wt% or less (excluding 0%). P: 0.1 wt% or less Phosphorus (P) not only plays a role in increasing the resistivity of the material, but also can improve the magnetic flux density as a grain boundary segregation element. However, if too much P is added, the brittleness of the steel plate increases, resulting in poor weldability. More specifically, P may be included in an amount of 0.0001 to 0.0500 wt%. More specifically, P may be included in an amount of 0.0010 to 0.0200 wt%. C: 0.005 wt% or less Carbon (C) can cause magnetic aging and combine with other impurity elements to form carbides, thereby hindering grain boundary or domain wall movement and deteriorating magnetic properties. More specifically, it can contain 0.0001 to 0.003 wt% of C. S: 0.005 wt% or less Sulfur (S) can form fine precipitates, MnS and CuS, thereby deteriorating magnetic properties and hot workability. More specifically, S can be included in an amount of 0.0001 to 0.0030 wt%. Ti: 0.005 wt% or less Titanium (Ti) has a very strong tendency to form precipitates inside the steel, and can deteriorate iron loss by forming fine carbides, nitrides, or sulfides inside the parent material, thereby inhibiting grain growth and domain wall movement. More specifically, it can contain 0.0001 to 0.0030 wt% of Ti. N: 0.005 wt% or less Nitrogen (N) not only forms fine AlN precipitates inside the parent material, but also combines with other impurities to form fine precipitates, thereby inhibiting grain growth and domain wall movement, thereby worsening iron loss. More specifically, N may be included in an amount of 0.0001 to 0.0030 wt%. A non-oriented electrical steel sheet according to one embodiment of the present invention may further contain 0.005 to 0.200 wt% of each or a combined amount of one or more of Sn, Sb, Bi, Pb, Ge, and As. Sn Tin (Sn) can be added to improve magnetism because it improves the aggregate structure of the material by segregating at grain boundaries and surfaces and plays a role in suppressing surface oxidation. If too much Sn is added, grain boundary segregation becomes severe, deteriorating the surface quality, increasing the hardness and causing fracture of the cold-rolled sheet, which can reduce the rollability. Specifically, Sn can be further included in an amount of 0.005 to 0.200 wt%. More specifically, it can be further included in an amount of 0.010 to 0.080 wt%. Sb Antimony (Sb) improves the material's aggregate structure by segregating at grain boundaries and surfaces and suppresses surface oxidation, so it can be additionally added to improve magnetism. If too much Sb is added, grain boundary segregation becomes severe, deteriorating the surface quality, increasing the hardness and causing breakage of the cold-rolled sheet, which can reduce the rollability. Specifically, 0.005 to 0.200 wt% of Sb can be further included. More specifically, 0.010 to 0.080 wt% can be further included. Bi, Pb, Ge and As When added, bismuth (Bi), lead (Pb), germanium (Ge) and arsenic (As) segregate at grain boundaries, thereby relieving stress concentration at grain boundaries during cold rolling, and thus reducing stress concentration in the subsequent process of recrystallization annealing. <111> / ND By suppressing the recrystallization of the orientation grains, the magnetic flux density is improved. If these are added appropriately, the aforementioned effects can be additionally obtained, but if they are included in too much, a large amount of segregation may occur, suppressing grain growth and thus lowering the magnetic flux density and iron loss. A non-oriented electrical steel sheet according to one embodiment of the present invention may further include at least one of Cu: 0.005 to 0.2 wt%, Cr: 0.01 to 0.5 wt%, Ni: 0.05 wt% or less (excluding 0%), Zn: 0.01 wt% or less (excluding 0%), and Co: 0.05 wt% or less (excluding 0%). Cu: 0.005 to 0.200 wt% Copper (Cu) plays a role in forming sulfides with Mn. If Cu is added more, if too little is added, (Cu Mn)S may be finely precipitated, which may deteriorate magnetism. If too much Cu is added, high-temperature embrittlement may occur, which may form cracks during rolling or hot rolling. More specifically, Cu may be included in an amount of 0.01 to 0.10 wt%. Cr: 0.01 to 0.50 wt% Chromium (Cr) plays a role in improving iron loss by increasing resistivity. If too little Cr is added, the resistivity-increasing effect may not be sufficient. If too much Cr is included, the magnetic flux density may decrease. More specifically, Cr may be included in an amount of 0.10 to 0.45 wt%. Ni: 0.05 wt% or less Nickel (Ni) may react with impurity elements to form fine sulfides, carbides, and nitrides, which may have a detrimental effect on magnetism. More specifically, it may contain 0.001 to 0.03 wt% of Ni. Zn: 0.01 wt% or less Zinc (Zn) may act as an impurity and deteriorate magnetism when the content is excessive. Therefore, Zn may be added more within the above-mentioned range. More specifically, Zn may be included in an amount of 0.001 to 0.005 wt%. Co: 0.05 wt% or less Cobalt (Co) does not form fine-sized precipitates that reduce the magnetism of steel plates, but it can increase high-temperature strength and cause poor coil shape after hot rolling. A non-oriented electrical steel sheet according to one embodiment of the present invention may further include at least one of Mo: 0.03 wt% or less (excluding 0%), B: 0.0050 wt% or less (excluding 0%), V: 0.0050 wt% or less (excluding 0%), Ca: 0.0050 wt% or less (excluding 0%), Nb: 0.0050 wt% or less (excluding 0%), Zr: 0.0050 wt% or less (excluding 0%), Te: 0.0100 wt% or less (excluding 0%), and Mg: 0.0050 wt% or less (excluding 0%). Mo: 0.030 wt% or less Molybdenum (Mo) may suppress segregation of segregating elements when added in excess, thereby reducing the effect of improving the grain structure. Therefore, Mo may be included at 0.03 wt% or less. The lower limit is not particularly limited, but since it plays a role in improving the grain structure by segregating on the surface and grain boundaries, it may be included at 0.001 wt% or more. More specifically, Mo may be included at 0.001 to 0.010 wt%. More specifically, Mo may be included at 0.005 to 0.010 wt%. B: 0.0050 wt% or less If boron (B) is added in excessive amounts, it may cause deterioration of magnetism through the formation of inclusions in the steel. Therefore, B may be included in an amount of 0.005 wt% or less. The lower limit is not particularly limited, but may be 0.0001 wt% due to steelmaking costs. More specifically, B may be included in an amount of 0.0001 to 0.0030 wt%. V: 0.0050 wt% or less Vanadium (V) has a very strong tendency to form precipitates inside the steel, and forms fine carbides or nitrides inside the parent material, thereby inhibiting grain growth and domain wall movement, thereby deteriorating iron loss. Therefore, the V content may be 0.0050 wt% or less, respectively. The lower limit is not particularly limited, but may be 0.0003 wt% due to steelmaking costs. That is, V may be included in an amount of 0.0003 to 0.0050 wt%. More specifically, V may be included in an amount of 0.0003 to 0.0030 wt%. Ca: 0.0050 wt% or less Calcium (Ca) has a very strong tendency to form precipitates within the steel, and forms fine sulfides within the parent metal, which inhibits grain growth and domain wall movement, thereby deteriorating iron loss. Nb: 0.0050 wt% or less Niobium (Nb) has a very strong tendency to form precipitates inside steel, and forms fine carbides or nitrides inside the base metal, thereby inhibiting grain growth and domain wall movement, thereby deteriorating iron loss. Therefore, the Nb content may be 0.0050 wt% or less. The lower limit is not particularly limited, but may be 0.0003 wt% due to steelmaking costs. That is, Nb may be included in an amount of 0.0003 to 0.0050 wt%. More specifically, Nb may be included in an amount of 0.0003 to 0.0030 wt%. Zr: 0.0050 wt% or less If zirconium (Zr) is added in excessive amounts, it may cause deterioration of magnetism through the formation of inclusions in the steel, etc. Therefore, Zr may be included in an amount of 0.005 wt% or less. The lower limit is not particularly limited, but may be set to 0.0001 wt% due to steelmaking costs. That is, Zr may be included in an amount of 0.0001 to 0.0050 wt%. More specifically, it may be included in an amount of 0.0005 to 0.0030 wt%. Te: 0.0100 wt% or less Tellurium (Te) can be added to prevent the oxide layer fractured during rolling from being pressed into the base metal and being removed by diffusing into the oxide layer on the surface of a hot-rolled coil and increasing the coefficient of friction between the oxide layer and the rolling work rolls, while being concentrated under the oxide layer to improve hardness. If the amount of Te added is too small, the effect may be minimal. If too much Te is added, the oxide layer is easily removed and the base metal comes into direct contact with the work rolls, reducing the effect, and during cold rolling, deformation bands may be excessively generated in the steel sheet, which may lead to the development of a {111} / ND texture, which is unfavorable to magnetism. More specifically, tellurium may be included in an amount of 0.0001 to 0.007 wt%. Mg: 0.0050 wt% or less Magnesium (Mg) is an element that mainly forms sulfide by combining with S, and can affect the surface oxide layer of the steel. Therefore, Mg may be included in an amount of 0.0050 wt% or less. The lower limit is not particularly limited, but may be set to 0.0001 wt% due to the cost of steelmaking. That is, Mg may be included in an amount of 0.0001 to 0.0050 wt%. More specifically, it may be included in an amount of 0.0005 to 0.0030 wt%. The remainder includes Fe and unavoidable impurities. The unavoidable impurities are impurities mixed in during the steelmaking step and the manufacturing process of the non-oriented electrical steel sheet, and since this is widely known in the relevant field, a detailed description is omitted. In one embodiment of the present invention, the addition of elements other than the alloy components described above is not excluded, and various elements may be included within a range that does not impair the technical idea of ​​the present invention. When additional elements are further included, they are included in place of the remainder Fe. As described above, in one embodiment of the present invention, by appropriately controlling the alloy composition of the steel plate and performing hot-rolled sheet annealing in two processes including pickling, the development of a specific aggregate structure can be suppressed. In one embodiment of the present invention, the area fraction of crystal grains in which the

[0341] direction is parallel to the rolling direction of the steel sheet within 15° and the (111) plane is parallel to the rolling plane of the steel sheet within 15° (hereinafter, also referred to as “(111)

[0341] crystal grains”) is 15% or less. (111)

[0341] grains are prone to slip deformation at high temperatures, which deteriorates mechanical properties at high temperatures. If there are too many (111)

[0341] grains, the mechanical properties at 2000°C may deteriorate rapidly. More specifically, (111)

[0341] grains may be in the range of 5.0 to 13.0 area%. The area fraction of (111)

[0341] grains can be measured using SEM-EBSD. At this time, the tolerance can be within 15°. According to one embodiment of the present invention, the non-oriented electrical steel sheet may have an average grain size of 100 ㎛ or less. If the average grain size is too large, it may adversely affect the basic mechanical strength. More specifically, the average grain size may be 20 to 90 ㎛. The average grain size can be measured by dividing the number of grains by the total area by observing a cross-section including the steel sheet thickness direction with an optical microscope. The grain size can be calculated as the diameter of a circle assuming the same area. In one embodiment of the present invention, the mechanical strength is excellent even at a high temperature of 200°C. Specifically, the non-oriented electrical steel sheet according to one embodiment of the present invention can satisfy the following equation 1. [Formula 1] (YS 200℃ ×TS 200℃ ×EL 200℃ ) / ( YS 25℃ ×TS 25℃ ×EL 25℃ ) ≥ 0.60 (YS in Equation 1 200℃ , TS 200℃ and EL 200℃ represents the yield strength, tensile strength and elongation measured at 200℃, respectively. YS 25℃ , TS 25℃ and EL 25℃ ) represent the yield strength, tensile strength and elongation measured at 25℃, respectively. Equation 1 means that the mechanical properties of the non-oriented electrical steel sheet deteriorate little at 200℃. If the value is too small, it means that the mechanical properties at 200℃ are insufficient, and the mechanical properties deteriorate when the motor is driven, which may reduce the life of the motor. More specifically, the value of Equation 1 may be 0.60 to 0.80. More specifically, the value of Equation 1 may be 0.63 to 0.75. In addition, a non-oriented electrical steel sheet according to one embodiment of the present invention can satisfy the following equation 2. [Formula 2] (YS 150℃ ×TS 150℃ ×EL 150℃ ) / (YS 200℃ ×TS 200℃ ×EL 200℃ ) ≥ 1.100 (YS in Equation 2 150℃ , TS 150℃ and EL 150℃ represents the yield strength, tensile strength and elongation measured at 150℃, respectively. YS 200℃ , TS 200℃ and EL 200℃ ) represent the yield strength, tensile strength and elongation measured at 200℃, respectively. Equation 2 means that the mechanical characteristics are the best at 150℃, which is the temperature at which the motor is driven. If the value is too small, it means that the mechanical characteristics at 150℃ are insufficient, and the mechanical characteristics deteriorate when the motor is driven, which may shorten the life of the motor. More specifically, the value of Equation 2 can be 1.100 to 1.300. In one embodiment of the present invention, a tensile test specimen is manufactured with a parallel section width of 12.5 mm and a parallel section length of 50 mm (based on Type 1 of ISO 6892-1), and the tensile speed is 30 MPa / s until yield and can be tested at a speed of 0.0067 / s thereafter. The tensile tester is equipped with a temperature chamber, and a thermocouple can be attached to the specimen to perform a test at each temperature. The yield strength and elongation can be measured with the values ​​of the Load Cell and Strain Gauge. In one embodiment of the present invention, the yield strength at room temperature (25°C) can be 430 to 570 MPa. The yield strength at 70°C can be 400 to 550 MPa. The yield strength at 150°C can be 370 to 520 MPa. The yield strength at 200°C can be 330 to 500 MPa. More specifically, the yield strength at room temperature (25°C) can be 440 to 550 MPa. The yield strength at 70°C can be 420 to 530 MPa. The yield strength at 150°C can be 390 to 500 MPa. The yield strength at 200°C can be 350 to 480 MPa. In one embodiment of the present invention, the tensile strength at room temperature (25°C) may be 550 to 720 MPa. The tensile strength at 70°C may be 500 to 700 MPa. The tensile strength at 150°C may be 480 to 690 MPa. The tensile strength at 200°C may be 480 to 690 MPa. More specifically, the tensile strength at room temperature (25°C) may be 560 to 700 MPa. The tensile strength at 70°C may be 520 to 680 MPa. The tensile strength at 150°C may be 500 to 670 MPa. The tensile strength at 200°C may be 500 to 670 MPa. In one embodiment of the present invention, the elongation at room temperature (25°C) may be 5 to 25%. The elongation at 70°C may be 5 to 25%. The elongation at 150°C may be 5 to 25%. The elongation at 200°C may be 5 to 25%. More specifically, the elongation at room temperature (25°C) may be 5 to 20%. The tensile strength at 70°C may be 5 to 20%. The elongation at 150°C may be 5 to 18%. The elongation at 200°C may be 5 to 18%. In one embodiment of the present invention, the ratio of the YS×TS×EL values ​​at 70°C to the YS×TS×EL values ​​at 25°C (75°C / 25°C) may be 0.70 to 0.95. More specifically, it may be 0.75 to 0.93. In one embodiment of the present invention, the ratio of the YS×TS×EL values ​​at 150°C to the YS×TS×EL values ​​at 25°C (150°C / 25°C) may be 0.65 to 0.90. More specifically, it may be 0.70 to 0.85. A method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention includes a step of hot-rolling a slab to manufacture a hot-rolled steel sheet; a cold-rolling pre-annealing step of annealing the hot-rolled steel sheet; a step of cold-rolling the hot-rolled steel sheet to manufacture a cold-rolled sheet; and a cold-rolled sheet annealing step of annealing the cold-rolled sheet. Below, each step is explained in detail. First, the slab is hot rolled. Since the alloy composition of the slab has been described in the alloy composition of the non-oriented electrical steel sheet mentioned above, a duplicate description will be omitted. Since the alloy composition does not substantially change during the manufacturing process of the non-oriented electrical steel sheet, the alloy composition of the non-oriented electrical steel sheet and the slab are substantially the same. Specifically, the slab contains Si: 1.5 to 5.0% by weight, Al: 0.1 to 2.0%, Mn: 0.1 to 2.0%, and the remainder includes Fe and inevitable impurities. As for other additional elements, they have been described in the alloy composition of non-oriented electrical steel sheets, so any duplicate description will be omitted. The slab can be heated before hot rolling. The heating temperature of the slab is not limited, but the slab can be heated to 1200℃ or lower. If the slab heating temperature is too high, precipitates such as AlN and MnS present in the slab may be re-dissolved and then finely precipitated during hot rolling and annealing, which may inhibit grain growth and reduce magnetism. Next, the slab is hot rolled to manufacture a hot-rolled plate. The thickness of the hot-rolled plate can be 1.0 to 4.5 mm. In the step of manufacturing the hot-rolled plate, the finishing rolling temperature can be 800°C or higher. Specifically, it can be 800 to 1000°C. The hot-rolled plate can be coiled at a temperature of 600°C or higher. More specifically, the thickness of the hot-rolled plate can be 1.5 to 4.3 mm. After manufacturing the hot-rolled plate, a step of preparatory cold rolling the hot-rolled plate may be further included. Preparatory cold rolling is distinguished from cold rolling, which will be described later, in that it is the first rolling step in the process of rolling to an intermediate thickness other than the final product thickness, then performing intermediate annealing, and then cold rolling to the final product thickness. Preliminary cold rolling can be performed in the reduction ratio range of 40 to 80% for final cold rolling productivity and grain improvement in the final product plate. In addition, when the rolling productivity is not considered, it is also possible in the present invention to perform preliminary cold rolling in a reverse mill. The preliminarily cold rolled plate can have a thickness of 0.30 to 1.50 mm. More specifically, the reduction ratio can be 50 to 78% and the thickness can be 0.40 to 1.00 mm. The preliminary cold rolling reduction can be calculated as (steel thickness before rolling - steel thickness after rolling) / steel thickness before rolling. If the reduction ratio is too low in the preliminary cold rolling stage, the rolling load increases during the final cold rolling, which reduces productivity, and the final reduction ratio increases, which causes fine <111> Problems that promote azimuth re-determination may arise. Conversely, if the reduction ratio is too high, the cold rolling load increases and the possibility of plate fracture also increases. Next, in the annealing step before cold rolling, the hot rolled steel sheet is annealed. If preliminary cold rolling is additionally performed, the preliminary cold rolled steel sheet can be annealed. In one embodiment of the present invention, the cold rolling pre-annealing step includes a first annealing step, a pickling step, and a second annealing step. By including an annealing step that includes pickling in the middle, initial recrystallization in the surface oxide layer can be suppressed, thereby suppressing the growth of specific crystal grains. The first annealing step can be cracked at a temperature of 950 to 1050°C. If the annealing temperature is too low, the recrystallized structure is not formed or grows finely, so that the effect of increasing the magnetic flux density is small. If the annealing temperature is too high, the magnetic properties may rather deteriorate, and the rolling workability may deteriorate due to deformation of the plate shape. More specifically, the cracking can be performed at a temperature of 980 to 1030°C. Next, the steel plate is pickled. In this process, the scale existing on the steel plate is removed. Since the pickling solution is widely known, a detailed description will be omitted, and a general pickling solution can be used. The pickling can be performed at a temperature of 10 to 100℃ in the pickling step. If the temperature is too low, the pickling may not be performed properly. If the pickling temperature is too high, excessive grain boundary erosion due to overpickling may occur, which may cause a problem of fracture during rolling. More specifically, the pickling temperature can be 30 to 80℃. Next, cracking can be performed at a temperature of 500 to 700°C in the second annealing step. If the annealing temperature is too low, the grain growth is low, so there are many fine grains, and the grain size is not uniform, which can be a problem. If the annealing temperature is too high, the grains grow excessively, which can be a problem with plate breakage during rolling. More specifically, cracking can be performed at a temperature of 550 to 650°C. Additional pickling may be performed after the second annealing step. The pickling conditions are the same as the pickling process described above. Next, the hot rolled steel sheet is cold rolled to manufacture a cold rolled sheet. At this time, cold rolling can be performed at a reduction ratio of 40 to 85%. If the reduction ratio is too low, the accumulated strain energy in the rolled steel sheet is small, making it difficult to recrystallize in the subsequent annealing process, so that the rolled structure remains, which can cause problems in improving the magnetic flux density and iron loss. On the other hand, if the reduction ratio is too high, it can cause problems in the subsequent annealing process. <111> / ND The problem may occur that recrystallization of the orientation grains is promoted and the grains become finer, resulting in inferior magnetic flux density and increased iron loss. More specifically, the reduction ratio may be 60 to 75%. The cold rolling step may use a Tandem cold rolling mill that continuously cold-rolls the steel sheet using a plurality of rolling stands, or a Reverse rolling mill that discontinuously cold-rolls the steel sheet using 12 or more rolling rolls. The final rolled thickness may be 0.1 mm to 0.35 mm. The process of manufacturing cold rolled sheets can be performed once or twice or more with intermediate annealing in between. Next, the cold rolled sheet is annealed in the cold rolled sheet annealing step. In one embodiment of the present invention, by controlling the heating rate in a specific temperature range during heating during the cold rolled sheet annealing, the mechanical properties can be further improved. Specifically, before the cold rolled sheet annealing step, the temperature can be increased to a temperature range of 300 to 800°C so as to satisfy the following equation 3. [Formula 3] [Cr] × [heating rate] ≥ 50 (In Equation 3, [Cr] is the content of Cr in the slab (weight%), and the heating rate represents the average heating rate of the steel plate (℃ / sec) in the temperature range of 300 to 800℃.) Alternatively, the temperature range of 300 to 800°C may be increased at a heating rate of 150 to 300°C / s prior to the cold rolled sheet annealing step. If the heating rate is too low, recrystallization may occur at grain boundaries, forming a large number of (111)

[0341] grains and deteriorating mechanical properties. More specifically, the value of Equation 3 may be 60 to 150. Or, the heating rate may be 160 to 270°C / s. The cold rolled sheet annealing step can be annealed at a soaking temperature of 900 to 1050°C for 60 seconds or less. If the soaking temperature is too low, the grains may not grow sufficiently, which may cause an increase in hysteresis loss and a deterioration of iron loss. If the soaking temperature is too high or the time is long, the grains may become too large and the mechanical properties may deteriorate. More specifically, the soaking temperature may be 930 to 1030°C. The soaking time may be 30 to 55 seconds. During the cold rolled sheet annealing process, all (i.e., more than 99%) of the processed structures formed during the cold rolling stage can be recrystallized. After cold-rolled sheet annealing, an insulating film can be formed. The insulating film can be treated with an organic, inorganic, or organic-inorganic composite film, and it can also be treated with other insulating film agents. Hereinafter, the present invention will be described in more detail through examples. However, these examples are only for illustrating the present invention, and the present invention is not limited thereto. Example 1 A slab was manufactured with the components shown in Table 1 and the remainder including Fe and inevitable impurities. The C, S, N, and Ti of the slab were all controlled to 0.0025 wt%. The slab was heated to 1150°C and hot-rolled at a finishing temperature of 850°C to manufacture a hot-rolled plate with a thickness of 2.0 mm. After that, the hot-rolled plate was first annealed at 1,000℃ for 4 minutes and then pickled at 78℃. Again, it was second annealed at 600℃ for 3 minutes and pickled at 75℃. Steel grades 9 to 11 were only first annealed at 1,000℃ for 4 minutes. Then, it was cold rolled to produce a thickness of 0.25 mm. The conditions for annealing the cold-rolled plate are shown in Table 2, and the soaking temperature is 960℃. The tensile test specimens were manufactured with a parallel section width of 12.5 mm and a parallel section length of 50 mm (based on Type 1 of ISO 6892-1). The tensile speed was 30 MPa / s until yield and then 0.0067 / s. The tensile tester was equipped with a temperature chamber, and a thermocouple was attached to the specimen to conduct the test at each temperature. The yield strength was measured using a load cell with an offset of 0.2%. The elongation was measured with a strain gauge attached to the specimen. (111)

[0341] The fraction was measured by SEM-EBSD and the tolerance was within 15°. Steel gradeSiAlMnCuCrResistivity(μΩ cm)13.60.80.800.050.47023.80.80.800.050.47233.60.82.500.050.48043.60.80.800.050.47053.10.81.200.050.46763.40.50.950.050.46573.72.11.500.050.49084.20.80.500.050.47593.50.80.700.050.468103.40.80.700.050.467113.60.70.700.050.468 Steel grade Pre-annealing 2 times Presence or absence of heating rate (℃ / sec) Cracking time (sec) Grain size (㎛) (111)

[0341] Fraction (area %) 1O2004084102O255064183O1803052144O2504535115O30048105176O1602527107O1905078128O2705062139X20050621610X25052801811X280486720 Steel type Measuring temperature (℃) YS (0.2) (MPa) TS (MPa) EL (%) Ratio of YS × TS × EL at 25℃ Ratio of YS × TS × EL at 200℃ at 150℃ Bibigo12544556317--Invention Example170425523150.78-Invention Example1150395520150.72-Invention Example1200367529140.641.134Invention Example22546558715--Comparative Example270430565150.89-Comparative Example2150412542130.71-Comparative Example2200365532120.571.246Comparative Example32545257618--Comparative Example370425565160.82-Comparative Example3150387542140.63-Comparative Example3 200365532140.581.080Comparative Example 42548860217--Invention Example 470462578160.86-Invention Example 4150432565160.78-Invention Example 4200415570150.711.101Invention Example 525408515221-Comparative Example 570388495200.83-Comparative Example 5150362475170.63-Comparative Example 5200341465170.581.084Comparative Example 625520642191-Invention Example 670495615190.91-Invention Example 61 50465605180.80-Invention Example 6200435620170.721.104Invention Example 725515632121-Comparative Example 770478611110.82-Comparative Example 7150435589110.72-Comparative Example 7200398579100.591.223Comparative Example 82554266161-Invention Example 87050763560.90-Invention Example 815047863160.84-Invention Example 820044763750.661.271Invention Example 925475582131.0-Comparative Example 970 45256160.42-Comparative Example915043154160.39-Comparative Example920042953150.321.228Comparative Example1025435567131-Comparative Example1070425547100.73-Comparative Example1015038949090.54-Comparative Example1020038147090.501.064Comparative Example1125442562101-Comparative Example117041254190.81-Comparative Example1115037851240.31-Comparative Example1120038048540.301.050Comparative Example As shown in Tables 1 to 3, when the steel component is appropriately controlled and the process conditions are appropriately controlled to suppress (111)

[0341] formation, it can be confirmed that the mechanical properties at 150°C and 200°C are excellent. On the other hand, when the steel component is not properly controlled and the process conditions are not properly controlled, so that (111)

[0341] is not formed in large numbers, it can be confirmed that the mechanical properties at 150°C and 200°C are excellent. The present invention is not limited to the embodiments, but can be manufactured in various different forms, and a person having ordinary skill in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims

Contains Si: 1.5 to 5.0% by weight, Al: 0.1 to 2.0%, Mn: 0.1 to 2.0%, and the remainder includes Fe and inevitable impurities. (111)[341] Non-oriented electrical steel sheet having an area fraction of grains within a range of 15° of 15% or less. In the first paragraph, Non-oriented electrical steel sheet further comprising at least one of P: 0.1 wt% or less (excluding 0%), C: 0.005 wt% or less (excluding 0%), S: 0.005 wt% or less (excluding 0%), Ti: 0.005 wt% or less (excluding 0%), and N: 0.005 wt% or less (excluding 0%). In the first paragraph, A non-oriented electrical steel sheet further comprising 0.005 to 0.200 wt% of each or a combined amount of one or more of Sn, Sb, Bi, Pb, Ge and As. In the first paragraph, A non-oriented electrical steel sheet further comprising at least one of Cu: 0.005 to 0.2 wt%, Cr: 0.01 to 0.5 wt%, Ni: 0.05 wt% or less (excluding 0%), Zn: 0.01 wt% or less (excluding 0%), and Co: 0.05 wt% or less (excluding 0%). In the first paragraph, Non-oriented electrical steel sheet further comprising at least one of Mo: 0.03 wt% or less (excluding 0%), B: 0.0050 wt% or less (excluding 0%), V: 0.0050 wt% or less (excluding 0%), Ca: 0.0050 wt% or less (excluding 0%), Nb: 0.0050 wt% or less (excluding 0%), Zr: 0.005 wt% or less (excluding 0%), Te: 0.01 wt% or less (excluding 0%), and Mg: 0.0050 wt% or less (excluding 0%). In the first paragraph, Non-oriented electrical steel sheet with an average grain size of 100㎛ or less. In the first paragraph, A non-oriented electrical steel sheet satisfying the following equation 1. [Formula 1] (YS 200℃ ×TS 200℃ ×EL 200℃ ) / ( YS 25℃ ×TS 25℃ ×EL 25℃ )≥ 0.60 (YS in Equation 1 200℃ , TS 200℃ and EL 200℃ represents the yield strength, tensile strength and elongation measured at 200℃, respectively. YS 25℃ , TS 25℃ and EL 25℃ ) represent the yield strength, tensile strength and elongation measured at 25℃, respectively. In the first paragraph, A non-oriented electrical steel sheet satisfying the following equation 2. [Formula 2] (YS 150℃ ×TS 150℃ ×EL 150℃ ) / (YS 200℃ ×TS 200℃ ×EL 200℃ ) ≥ 1.1 (YS in Equation 2 150℃ , TS 150℃ and EL 150℃ represents the yield strength, tensile strength and elongation measured at 150℃, respectively. YS 200℃ , TS 200℃ and EL 200℃ ) represent the yield strength, tensile strength and elongation measured at 200℃, respectively. A step of manufacturing a hot-rolled steel sheet by hot-rolling a slab containing Si: 1.5 to 5.0% by weight, Al: 0.1 to 2.0%, Mn: 0.1 to 2.0% by weight, and the remainder being Fe and unavoidable impurities; A cold rolling pre-annealing step for annealing the above hot rolled steel sheet; A step of manufacturing a cold rolled sheet by cold rolling the hot rolled steel sheet above, and A cold rolled sheet annealing step for annealing the above cold rolled sheet; Including, A method for manufacturing a non-oriented electrical steel sheet, wherein the cold rolling annealing step comprises a first annealing step, a pickling step, and a second annealing step. In Article 9, A method for manufacturing a non-oriented electrical steel sheet, wherein the above slab further includes at least one of P: 0.1 wt% or less (excluding 0%), C: 0.005 wt% or less (excluding 0%), S: 0.005 wt% or less (excluding 0%), Ti: 0.005 wt% or less (excluding 0%), and N: 0.005 wt% or less (excluding 0%). In Article 9, A method for manufacturing a non-oriented electrical steel sheet, wherein the above slab further contains 0.005 to 0.200 wt% of each or a combined amount of one or more of Sn, Sb, Bi, Pb, Ge and As. In Article 9, A method for manufacturing a non-oriented electrical steel sheet, wherein the above slab further includes at least one of Cu: 0.005 to 0.2 wt%, Cr: 0.01 to 0.5 wt%, Ni: 0.05 wt% or less (excluding 0%), Zn: 0.01 wt% or less (excluding 0%), and Co: 0.05 wt% or less (excluding 0%). In Article 9, A method for manufacturing a non-oriented electrical steel sheet, wherein the above slab further includes at least one of Mo: 0.03 wt% or less (excluding 0%), B: 0.0050 wt% or less (excluding 0%), V: 0.0050 wt% or less (excluding 0%), Ca: 0.0050 wt% or less (excluding 0%), Nb: 0.0050 wt% or less (excluding 0%), Zr: 0.005 wt% or less (excluding 0%), Te: 0.01 wt% or less (excluding 0%), and Mg: 0.0050 wt% or less (excluding 0%). In Article 9, A method for manufacturing a non-oriented electrical steel sheet in which the first annealing step is performed at a temperature of 950 to 1050°C. In Article 9, A method for manufacturing a non-oriented electrical steel sheet in which the above pickling step is performed at a temperature of 10 to 100°C. In Article 9, A method for manufacturing a non-oriented electrical steel sheet which is cracked at a temperature of 500 to 700°C in the second annealing step. In Article 9, A method for manufacturing a non-oriented electrical steel sheet, comprising a pickling step after the second annealing step. In Article 9, The above slab further contains Cr: 0.01 to 0.5 wt%, A method for manufacturing a non-oriented electrical steel sheet, wherein the temperature is increased to a temperature range of 300 to 800°C prior to the cold rolled sheet annealing step so as to satisfy the following equation 3. [Formula 3] [Cr] × [heating rate] ≥ 50 (In Equation 3, [Cr] is the content of Cr in the slab (weight%), and the heating rate represents the average heating rate of the steel plate (℃ / sec) in the temperature range of 300 to 800℃.) In Article 9, A method for manufacturing a non-oriented electrical steel sheet, wherein the temperature is increased in a temperature range of 300 to 800°C at a heating rate of 150 to 300°C / s prior to the above-mentioned cold rolled sheet annealing step. In Article 9, A method for manufacturing a non-oriented electrical steel sheet, wherein the cold rolled sheet annealing step is performed at a soaking temperature of 900 to 1050°C for 60 seconds or less.