RU2092605C1 - Sheets of isotropic electrotechnical steel and method for their manufacturing - Google Patents

Abstract

FIELD: manufacturing of sheets of isotropic electrotechnical steel; may be used as material for strands of electrochemical machines and devices. SUBSTANCE: sheet is manufactured of isotropic electrotechnical steel which comprises, mas.%: carbon, less than 0.02; silicium, 1.0-3.5; manganese, less than 1.0; phosphorous, less than 0.1; sulfur, less than 0.01; nitrogen, less that 0.008; aluminium, less than 0.7; nickel, 0.05-1.0; copper, 0.02-0.5; tin and/or antimony, 0.02-0.2; ferrum, the balance. Four variants for choice of steel composition and six variants for choice of procedure for manufacturing of steel sheets are also proposed here. EFFECT: improved magnetic properties, decreased losses. 17 cl, 20 tbl

Description

 The invention relates to metallurgy, in particular, to a sheet of electrical steel used as the core material of electric machines and equipment, such as various electric motors, generators, small transformers, ballast chokes, etc., and manufacturing methods, and more particularly to isotropic sheets electrical steel with low losses of magnetization reversal power and high magnetic flux density and magnetic permeability and methods of manufacturing thereof.

Products made from sheets of isotropic electrical steel for electric machines can generally be classified by silicon content. Such products are considered to be of low quality if the silicon content is less than 1% of the middle class, if the silicon content is 1-2% and of the high class, if the silicon content exceeds 2%. This classification is based on the fact that steel losses decrease with increasing silicon content. However, the magnetic flux density and permeability decreases with increasing silicon content. High magnetic properties mean that losses in steel are small, and magnetic flux density and permeability are high. Since silicon
an element that increases the hardness of steel during cold deformation, it adversely affects the ability of steel to cold rolling during sheet manufacturing or punching during processing by consumers, therefore it is preferable to have a low silicon content and at the same time reduce losses if possible. Thus, there is a need to develop an isotropic steel sheet with a low silicon content, low losses and a high magnetic flux density and magnetic permeability.

 Losses in isotropic electrical steel for electric machines can be mainly divided into hysteresis losses and eddy current losses. Losses due to eddy currents are determined by the chemical composition of steel, sheet thickness, frequency, etc.

When using a normal frequency of 60 Hz, the hysteresis loss is more than 50%
However, eddy current losses can become greater than hysteresis losses in cases when work is carried out at higher frequencies. To reduce eddy current losses, you can add chemical elements with high resistivity, such as silicon and aluminum, or you can reduce the thickness of the steel sheet. In order to reduce losses due to chemical composition, thickness and frequency under the same conditions, it is necessary to reduce hysteresis losses. Since hysteresis losses are inversely proportional to grain size, the crystalline grains of the alloy should be as large as possible. Positioning the crystallographic plane (110) or (200) parallel to the surface of the sheet, i.e. By obtaining the texture (110) (U ₁ , V ₁ , W ₁ ) or (200) (U ₂ , V ₂ , W ₂ ), one can reduce losses, as well as improve magnetic flux density and permeability. Magnetic properties do not always improve in proportion to grain growth. But if the components of the (110) or (200) texture are well formed, and if the grain is significantly grown, the magnetic properties are improved.

 When the components of the (110) or (200) texture are well developed, and the (111) texture, which worsens the magnetic properties, is poorly developed or suppressed, the magnetic properties can be improved.

 In the method of growing grain there is a direction of selection of components and a direction of pure manufacturing technology. By greatly increasing the release of fine phases, one can easily grow grain in the final product. Although steel cleaning is a good method in terms of obtaining a favorable structure in terms of magnetic properties, the texture suppression method (111), etc. can be used. harmful in terms of magnetic properties, by adding special elements to control the structure.

 The manufacture of isotropic sheet electrical steel is carried out in the process of complete or incomplete redistribution. The steel ingot is heated, hot rolled, and the rolled sheet is pickled after annealing. In the full process, the hot rolled sheet is pickled, cold rolled, and annealed. Subsequent manufacturing operations are carried out by “consumers”. Incomplete, i.e. half process, hot-rolled sheet is pickled, cold rolled, intermediate annealed and then calibrated rolled with very low compression or sheet tempering (cold rolling with 3-5% compression). Subsequent processing, including annealing with stress relieving, is carried out by "consumers". In the case of a complete process, rolling is carried out, including the first stage of cold rolling, the second stage of cold rolling is carried out after intermediate annealing. This method also falls under the complete process since high temperature annealing is carried out after the second cold rolling.

 Since the isotropic half-process steel sheet was calibrated or rolled with tempering, “consumers” must perform stress-relief annealing after processing at home. This stress relieving annealing aims to grow grain and relieve stress after processing.

 As for isotropic sheets of electrical steel made during the complete redistribution, more or less internal stresses appear as a result of processing by the "consumer", and these residual stresses can be removed by high-temperature annealing. As a result, the magnetic properties during annealing with stress relieving at the “consumer” can be improved.

 From the prior art for the production of non-oriented steel electrical sheet, a method is known to improve magnetic permeability even at high losses by reducing the content of silicon or aluminum in steel, but this method finds only limited use due to the high energy consumption for its implementation. In addition, a known method of reducing losses by increasing the content of silicon or aluminum in the steel, which provides a low magnetic flux density and permeability. The disadvantage of this method is to reduce the efficiency of electrical machines. Korean patent applications NN 88-017514, 88-017924 and 98-020173 suggest adding elements such as zirconium and boron to antimony-containing steel, but the structure and growth of crystalline grains useful for magnetic properties in the final product were insufficient. Korean Patent Application No. 91-5867 proposes a winding method in a protective atmosphere after rolling with compression of a sheet thickness of more than 15% carried out in the ferrite phase during hot rolling. According to this method, however, without the addition of special elements, such as tin, nickel and copper, the crystalline grain turned out to be small, and the structure was not sufficiently favorable for magnetic properties. US Pat. No. 4,204,890 provides a method for improving magnetic properties by developing a structure by continuously annealing or annealing in a container a hot-rolled sheet of antimony-containing steel. The disadvantage of this method is the need to minimize sulfur content to ensure grain growth. Japanese Patent No. 63-3176276 describes a half-process steel containing one or more of two elements from the group comprising tin, antimony, nickel and copper and an addition of manganese in an amount of 1-1.5%, as well as a method for manufacturing such steel. In this method, excessive addition of manganese leads to a rise in price. In addition, since manganese is an element that easily forms the austenitic phase, it goes into the austenitic phase up to a low temperature, and therefore the disadvantage of this method is its weak magnetic properties and, in particular, low magnetic flux density due to hot rolling in the austenitic phase.

 The invention provides an isotropic steel electrical sheet with excellent magnetic properties and a method for manufacturing this sheet in half or full process by appropriately selecting a system of components in steel.

 The invention lies in the fact that the system of starting components includes additives of one or two additional components, tin and antimony, introduced simultaneously, in addition to additives of copper and nickel to steel containing a maximum of 3.5% silicon, a maximum of 0.7% aluminum and less than 1% Manganese In addition to these elements, carbon, calcium or rare earth elements and phosphorus can be added. To improve the magnetic properties, the presence of other impurities, for example, oxygen, sulfur, and nitrogen in minimal amounts, is also useful, but a certain amount of these impurities is inevitable. If you add a lot of carbon, you need decarburization annealing. The addition to the system of components of only one of the elements, nickel or carbon, in addition to one or both of the elements, tin or antimony, is not a sign of the invention. Only when the alloy contains nickel and copper, as well as one or both of the elements, tin and antimony, which must be added at the same time, is the hallmark of the invention. These elements create textures that are advantageous for improving magnetic properties, for example in the (110) plane and (200) plane, and in particular, provide good growth of crystalline grains.

 A steel slab made of steel, smelted either in a converter, or in an electric furnace, etc., can be produced by continuous casting or by rough blooming, and then it is fed into a heating furnace in a heated or cooled state. A steel ingot heated in a heating furnace is hot rolled, then coiled and cold rolled after pickling and comes out in the form of an annealed or unannealed hot rolled sheet. Cold-rolled sheets can be produced in the process of full or half redistribution. A complete process is a process in which pickling of a hot-rolled sheet is carried out, then cold rolling in one stage or two stages, and then the final high-temperature annealing is carried out. The half process is the process by which the first cold rolling of a hot-rolled sheet is carried out, calibration or rolling with tempering after intermediate annealing, and stress-relieving annealing should be carried out by the "consumer". Each processing mode from the above may vary depending on the composition of the steel. Even if the steel contains the same amount of additives, a change in one manufacturing step can change the subsequent steps in the manufacturing process.

 In the invention, continuous annealing of the hot rolled sheet may be performed, or the annealing process of the hot rolled sheet may be absent when controlling the composition of the steel and the conditions of the hot rolling, so that the final hot rolling can be carried out under the conditions of the ferrite phase. In the manufacture of this method, it is possible to produce an isotropic steel electrical sheet with low losses and with a high magnetic flux density and high permeability.

 Of course, annealing in containers of hot-rolled sheet can improve magnetic properties, but the degree of improvement in magnetic properties does not justify an increase in costs.

 The inventor of this process conducted the following experiment to test how the finish temperature affects magnetic properties.

High temperature compression tests were carried out on steel made from an ingot containing, by weight. carbon 0.003; silicon 0.61; manganese 0.25; phosphorus 0.05; sulfur 0.008; nitrogen 0.004; oxygen 0.002; 0.27 aluminum; nickel 0.09; copper 0.075; tin 0.09; the rest is iron and inevitable impurities. This ingot was hot rolled, then cylinders 13 mm high and 8 mm in diameter were cut. The temperature during the compression test was maintained at 840 ^° C for the ferrite phase and 930 ^° C for the austenitic phase.

Studies of the microstructure after compression deformation were carried out at these temperatures, the study of the structure under the action of deformation only when cooled by air. Compression deformations were carried out upon cooling at a rate of 10 ^° C for 1 h from 800 ^° C, and after the last process in the sample deformed at 840 ^° C in the ferrite phase, elongated grains were obtained in the microstructure formed after deformation. A sample deformed at 930 ^° C in the austenitic phase had a recrystallization structure. It was confirmed that in the microstructure, after cooling, the grain almost did not grow in the sample deformed at 930 ^° C, but in the case of the microstructure deformed at 840 ^° C, the grain grew significantly.

 This is the result of dynamic recrystallization, since the energy of stacking defects in the austenitic phase is small and, therefore, the volumetric residual deformation of the sample is small, and on the other hand, after deformation in the ferrite phase, significant volumetric deformation is preserved, since dynamic recovery occurs only at high energy packaging defects.

 Accordingly, the residual strain in the samples after finishing rolling in the ferrite phase is larger than for the austenitic phase after finishing rolling, and thus the grain grows even when the hot-rolled sheet is rolled into a roll at high temperature or during continuous annealing of the hot-rolled sheet.

 According to this invention, a grain size of more than 25 μm is obtained in the production of a sheet by the complete process and a grain size of more than 50 μm in the production of the half process, even with all changes caused by different silicon contents.

Magnetic properties do not improve in proportion to grain size, and a structure favorable to magnetic properties must also be formed. The steel slab of the composition described above was heated to 1230 ^o C, rolled with a decrease in thickness by 19% at 840 ^o C and at 930 ^o C for finishing hot rolling, cooled at a speed of 15 ^o C for 1 h from 800 ^o C and then cold rolling a sheet with a thickness of 0.5 mm was obtained after pickling. High temperature annealing of cold rolled sheets was carried out in an atmosphere of a mixture of nitrogen and hydrogen for 2 min at 960 ^o C.

 As a result of the study of the magnetic properties of the sheet after high-temperature annealing, it turned out that the magnetic properties of the sample, hot rolling of which ended in the ferrite phase, were better than that of the sample, hot rolling of which ended in the austenitic phase.

 Compression tests were also carried out at high temperature for steel of the composition, wt. carbon 0.002; silicon 2.1; manganese 0.22; phosphorus 0.03; sulfur 0.005; nickel 0.12; copper 0.07; tin 0.06; the rest is iron and inevitable impurities. The result of observing the microstructures formed after cooling shows that phase transformation in the range of manufacturing conditions according to the invention is not observed due to the high content of silicon that is formed in the ferrite phase. A typical elongated grain appears in the ferrite phase. This shows that there is a correlation between the silicon content and the temperature zone of the finish rolling.

 A sheet of isotropic electrical steel made in accordance with the method according to the invention is characterized in that the losses therein are low even at a relatively low silicon content, and the magnetic flux density and permeability are high even at a relatively high silicon content.

 In isotropic steel electrical sheets according to the invention, an improvement in magnetic properties is determined by the fact that tin, antimony, etc. segregate along the boundaries of crystalline grains, preventing the introduction of elements due to their diffusion into the steel, and the formation of a crystalline structure is controlled. Copper forms large inclusions with sulfur and manganese. Since copper and nickel are added at the same time, corrosion resistance at high temperatures improves and scale growth slows down.

 Further, upon annealing, the grain size grows and a texture is better formed in the (110) and (200) planes, favorable for magnetic properties, due to the combined effect of alloying properties, due to the combined effect of alloying elements. This allows the production of isotropic electrical steel sheets with excellent magnetic properties.

There are many ways to indicate the structural characteristics of a steel sheet, but according to this invention, the structural coefficient and structural parameters were determined using the Hort formulas given below as formulas (1) and (2). Formula (1) determines the structural coefficient of the plane (hkl) arbitrarily selected in the steel sheet under study, and formula (2) defines the structure parameter as the ratio of structural coefficients for the planes (200), (100) and (310) favorable for magnetic properties and planes (211), (222) and (321), unfavorable for magnetic properties. In formula (1), I _hkl denotes the intensity of the texture of the measured test sample, I _Rkl denotes an arbitrary intensity of the standard test sample, and N _hkl denotes the multiplication factor. Magnetic properties improve with an increase in the texture intensity of the (200), (210) and (310) planes and a decrease in the texture intensity of the (211), (222) and (321) planes. Also, magnetic properties improve with an increase in the structural parameter, and the steel according to this invention has a structural parameter of at least 0.2.

где P_hkl структурный коэффициент.

where P _{hkl is the} structural coefficient.

где (T_p структурный параметр.

where (T _{p is the} structural parameter.

 The invention relates to an isotropic steel electrical sheet with enhanced magnetic properties, containing in high carbon less than 0.02; silicon 1.0-3.5; manganese less than 1.0; phosphorus less than 0.1; sulfur less than 0.01; nitrogen less than 0.008; aluminum less than 0.7; nickel 0.005-1.0; copper 0.02-0.5, with a total content of one or both alloying elements: tin and antimony 0.02-0.2%, the rest is iron and inevitable impurities.

 The invention further relates to an isotropic steel electrical sheet with improved magnetic properties, comprising a component or a number of components mentioned above, in which the crystalline grain has a size of more than 30 microns, preferably the grain size is in the range of 30-200 microns, and most preferably in the range of 60- 150 μm, and the structural parameter calculated by the Hort formula exceeds 0.2, preferably exceeds 0.5.

 The invention also relates to an isotropic steel electrical sheet with enhanced magnetic properties, containing, by weight. carbon less than 0.02; silicon less than 1; manganese less than 0.5; phosphorus less than 0.15, sulfur less than 0.01; nitrogen less than 0.008; oxygen less than 0,0005; aluminum less than 0.07; nickel 0.05-1.0; copper 0.02-0.5, with a total content of one or both alloying elements of tin and antimony 0.02-0.2%, the rest is iron and other inevitable impurities.

 The invention further relates to an isotropic steel sheet with enhanced magnetic properties, comprising a component or a number of components described above, the crystalline grain of which has a size of more than 20 microns, preferably the grain size is in the range of 20-250 microns, most preferably in the range of 40-200 μm, and the structural parameter calculated by the Hort formula exceeds 0.2 and preferably exceeds 0.5.

 The invention also relates to an isotropic steel electrical sheet with enhanced magnetic properties, containing, by weight. carbon less than 0.02; silicon less than 3.5; manganese less than 0.5; phosphorus less than 0.15; sulfur less than 0.01; nitrogen less than 0.008; aluminum less than 0.7; nickel 0.02-1.0; copper 0.02-0.5, with a total content of one or both alloying elements of tin and antimony 0.02-0.2% 0.001-0.02% calcium, and / or 0.00-0.03% rare earth element ( REE), the rest is iron and other inevitable impurities.

 The invention further relates to an isotropic steel sheet with enhanced magnetic properties, containing one component or a series of components described above, in which the grain size exceeds 30 microns, preferably the grain size is in the range of 30-250 microns, most preferably in the range of 50-200 microns and the structural parameter according to the Hort formula exceeds 0.2, preferably exceeds 0.5.

 The invention also relates to an isotropic steel electrical sheet with increased magnetic properties with the composition of the steel, wt. carbon 0.02-0.06; silicon less than 3.5; manganese less than 0.5; phosphorus less than 0.15; sulfur less than 0.01; nitrogen less than 0.008; aluminum less than 0.7; oxygen is less than 0.005; nickel 0.02-1.0; copper 0.02-0.5, with a total content of one or both alloying elements of tin and antimony 0.02-0.2%, the rest is iron and other inevitable impurities.

 The invention further relates to an isotropic electrical steel sheet with the above composition, in which the grain size exceeds 20 microns, preferably is in the range of 20-250 microns, most preferably 40-180 microns and the structural parameter according to the Hort formula is more than 0.3, preferably more 0.5.

The following describes the reasons for limiting the specified limits of the composition of the steel according to the invention. The aforementioned carbon, being an element that allows to obtain a structure favorable from the point of view of magnetic properties, may contain up to a maximum of 0.05%, taking into account the decarburization efficiency. However, in order to further reduce the residual carbon content, it is preferable that the carbon content is less than 0.02% (in case the carbon content in the slab exceeds 0.008%) decarburization annealing is possible. To prevent magnetic aging due to residual carbon, it is desirable to limit the content to less than 0.003%
Silicon mentioned above is the basic element that determines the magnetic properties of an isotropic sheet of electrical steel, it reduces the specific loss in steel by increasing the electrical resistivity of the material. However, it is desirable to have a silicon content below 3.5% since silicon impairs mechanical properties during cold rolling. In particular, when the silicon content is less than 1.0%, the rolling properties, as well as the magnetic flux density and permeability, are improved.

The above-mentioned manganese reduces losses in steel due to an increase in the electrical resistance of the material, but it can be precipitated by small inclusions in the form of manganese sulfide due to the connection with the sulfur present in the alloy, and this worsens the magnetic properties, and there is a problem of reducing the sulfur content to prevent this phenomenon . Considering also that more fine inclusions occur when the manganese content is above 0.1% if the heating temperature becomes above 1200 ^o C, it is desirable to limit the manganese content to below 1.0% and even better to below 0.5%
Since phosphorus reduces eddy current losses in steel by increasing the electrical resistivity and improves magnetic properties due to the development of the texture of the (200) and (110) planes, which are beneficial for improving the properties, its content can be increased to 0.15%. But since phosphorus increases the hardness of the starting material, it is desirable to limit the phosphorus content to 0.1% to improve the properties of steel during cold rolling.

 Sulfur is an unavoidable impurity, and therefore an improvement in magnetic properties is useful to prevent its content from increasing. But according to the invention, a sulfur content of up to 0.01% can also be allowed. Also according to the invention, even if the sulfur content reaches 0.015%, this will not affect the magnetic properties, provided that the manganese content is less than 0.5%. Even with a maximum increase in sulfur content, which adversely affects on magnetic properties up to 0.015%, the grain grows easily and thus magnetic properties can be improved. This is because the small amount of manganese and copper added form large sulfur inclusions, namely Mn / Cu / S. They are large inclusions formed instead of small and thin, as a result of which the grain grows well and a favorable structure is formed for magnetic properties.

 Since aluminum reduces losses in steel by increasing the electrical resistivity, it is added to form inclusions, for example, thin inclusions of aluminum nitride or to deoxidize a steel melt during steelmaking, but due to the increase in costs, it is desirable to increase the aluminum content to a maximum of 0.7% given the degree of improvement in magnetic properties.

Since nitrogen is an impurity that forms thin inclusions and worsens magnetic properties, it is advantageous that it be as small as possible and it is desirable to limit the content to a maximum of 0.008%
Oxygen is an impurity deoxidized by aluminum, etc. but an increase in the oxygen content in the final product during steel cooking increases the number of small non-metallic inclusions. It is desirable to reduce the oxygen content to a minimum to improve steel cleaning and beneficial grain growth. The (111) plane, etc., is unfavorable for magnetic properties and the texture associated with it can be weakened by a decrease in the oxygen content, preferably limiting its content to no more than 0.005%
Nickel has little effect when added separately, but in combination with copper, phosphorus, etc. promotes grain growth, obtaining a structure favorable for improving magnetic properties, and thus reduces losses in steel by increasing the electrical resistivity. But nickel is expensive, and therefore it is advisable to bring its content to 1.0%, taking into account the degree of improvement of magnetic properties and increased costs. Nickel also increases the corrosion resistance during high-temperature annealing, and the corrosion resistance of steels containing phosphorus, so it is desirable that its content is not less than 0.02% to improve magnetic properties. Nickel content in the range of 0.05-1.0% is preferred.
As for tin or antimony, you can add them together or any of them. These elements are added to regulate the formation of grains in the form of segregation elements to suppress texture in the (111) plane, which is unfavorable for magnetic properties, and develop structures favorable for magnetic properties. If the value of the additives of these elements is less than 0.02%, then their addition does not give an effect, and if the additives are higher than 0.2%, the cold rolling of the hot-rolled sheet is difficult. Accordingly, it is desirable to limit the total content of one or both of the elements of tin or antimony to 0.02-0.2%. However, if copper is contained in an amount of less than 0.4%, the content of tin or antimony can be brought to 0.3% individually or in combination.

Copper increases corrosion resistance, reduces losses in steel due to an increase in specific resistance, the formation of large phosphorous inclusions, promotes grain growth, promotes the formation of structures favorable for magnetic properties and a rapid increase in corrosion resistance of steels containing phosphorus. And when copper is added at the same time as nickel is added, it can slow down oxidation, especially at high temperatures. In order not to have cracks on the surface of hot-rolled steel sheets, into which elements separating the grain boundaries of the tin type and the like are simultaneously added. the maximum copper content should be 0.5%, while the magnetic properties are improved, starting with a content of at least 0.02%. Accordingly, the limits of the copper content must be set to 0.02-0.5%. However, in steel in which the content of tin or antimony is more than 0.2% individually or together the surface quality of the hot-rolled sheet can be satisfactory even with the addition of copper up to 0.4%
Calcium or rare earths can be added to steel independently or in combination. They contribute to grain growth during rough reduction by suppressing inclusions, in particular fine manganese sulfide, etc. due to which the magnetic properties of the product are improved. As for the rare-earth elements, the addition of one or more of them with a content of 0.003-0.03% makes it possible to suppress the formation of the surface structure (111), which impairs the magnetic properties, the formation of crystallization centers of which occurs around small dropping inclusions.

 The following describes a method for producing an isotropic sheet of electrical steel according to the invention.

 This invention relates to a method for manufacturing an isotropic sheet of electrical steel with improved magnetic properties in the process of complete redistribution, in which a steel slab containing, by weight. carbon less than 0.02; silicon 0-3.5; manganese less than 1.0; phosphorus less than 0.1; sulfur less than 0.01; nitrogen less than 0.008; aluminum less than 0.7; nickel 0.05-1.0; copper 0.02-0.5, with a total of one or both alloying elements of tin and antimony - 0.02-0.2%, the rest of the iron and inevitable impurities are subjected to hot rolling, annealing the hot rolled sheet, pickling, cold rolling first-order or second-order cold rolling, high-temperature annealing of a cold-rolled sheet and stress-relieving annealing.

After a steel slab with the specified composition is placed in a heating furnace before hot rolling, it is heated and subjected to hot rolling, while it is desirable to roll it at a temperature above 600 ^o C. The slab can be heated to 1250 ^o C.

After rolling the hot rolled sheet described above, it is annealed, and it is possible to conduct continuous annealing at 700-1100 ^o C for 10 s - 20 minutes or annealing in a container at 600-1000 ^o C for 30 minutes 10 hours. the grain does not grow enough with continuous annealing for less than 10 s, then the magnetic properties deteriorate. If the annealing time exceeds 20 minutes, then the equipment takes too long. As a result, continuous annealing is desirable for an interval of 10 s to 20 minutes.

 For the case of the annealing described above in the container, the annealing effect is small if the annealing time is less than 30 minutes, and the productivity decreases if the annealing lasts more than 10 hours. As a result, the annealing time in the box is limited to an interval of 30 minutes 10 hours.

 The hot-rolled sheet, which has undergone continuous annealing or annealing in the container, is subjected to pickling in the usual way, cold-rolled in one step, or cold-rolled first-order sheet is subjected to intermediate annealing, in the case of cold rolling of the second order in the case of two-stage cold rolling, high-temperature annealing is carried out.

This high-temperature annealing is carried out continuously in the temperature range of 700-1100 ^o C for a time of less than 10 minutes, and it is desirable to carry out annealing in a complete atmosphere of nitrogen or in a mixture of nitrogen with hydrogen.

If the carbon content in the cold-rolled sheet exceeds 0.008% before high-temperature annealing, decarburization can be carried out in a mixed atmosphere of nitrogen and hydrogen for an interval of less than 10 minutes, and the dew point of the atmosphere should be in the range of 20-70 ^o C. If the carbon content is more than 0.003%, at the request of the "consumer", heat treatment can be carried out by the "consumer" in a decarburizing atmosphere during annealing with stress relieving. An insulating coating can be applied after high-temperature annealing of this cold-rolled sheet, and a “consumer” can conduct a heat treatment heat treatment for the product without an insulating coating.

 It is desirable to control the conditions of the manufacturing process so that the grain size in an isotropic electrical steel sheet manufactured by the proposed method is 30 μm, preferably 30-200 μm and most preferably 60-150 μm and the structural parameter calculated by the Gort formula would be more than 0.2 preferably more than 0.5.

 Further, this invention relates to a method for manufacturing an isotropic sheet of electrical steel with improved magnetic properties in the process of half redistribution, in which a slab of steel containing, by weight. carbon less than 0.02; silicon less than 1.0; manganese less than 0.5; phosphorus less than 0.15; sulfur less than 0.01; nitrogen less than 0.008; oxygen is less than 0.005; aluminum less than 0.7; nickel 0.05-1.0; copper 0.02-0.5, with the content of one or both of the alloying elements of tin and antimony 0.02-0.2%, the remainder is iron and inevitable impurities, hot rolled, annealed hot rolled sheet, subjected to pickling, then cold rolling, intermediate annealing, then calibrated and annealed, and by the complete process, in which the steel slab with the above composition is hot rolled, the hot rolled sheet is annealed, then pickled, cold rolled and annealed.

After loading the steel slab of the composition described above into a hot rolling heating furnace, it is heated and hot rolled, then it is desirable to roll it at a temperature in excess of 600 ^° C.

The slab can heat up to 1300 ^o C.

After hot rolling, the final temperature of the finish rolling exceeds 750 ^o C, but is below the point A _r1 , in the ferritic phase. At the same time, the magnetic flux density and permeability of the product are bad if the final temperature of the finish rolling is higher than the point A _r1 , and when the temperature drops below 750 ^o C, the compression load during rolling becomes excessive.

The hot rolled sheet may then be annealed in a continuous process or in a container. With continuous annealing, it is desirable to conduct annealing at a temperature in the range of 700-1000 ^o C for an interval of 10 s to 20 m. Annealing in a container is carried out at temperatures in the range of 600-950 ^o C for an interval of 30 minutes 10 hours.

The grain does not grow sufficiently if continuous annealing is conducted for less than 10 s or the annealing temperature is below 750 ^o C, the magnetic properties deteriorate if annealing is carried out at a temperature above 1000 ^o C, and productivity decreases if the annealing time exceeds 20 minutes. As a result, it is desirable to limit the temperature of continuous annealing to a range of 700-1000 ^° C., and the annealing time to an interval of 10 s to 20 minutes.

If the temperature during annealing in the container is below 600 ^o C, and the annealing time is less than 30 minutes, the grain does not sufficiently increase and thus annealing does not have an effect. If the annealing temperature is higher than 950 ^o C, the magnetic properties deteriorate. Also, if the annealing time exceeds 10 hours, the process becomes uneconomical. As a result, it is necessary to limit the annealing temperature to a range of 600-950 ^o C, and the annealing time to a range of 30 minutes 10 hours. The atmosphere during annealing should be non-oxidizing. After annealing, the hot-rolled sheet is etched in a solution of hydrochloric acid and then subjected to cold rolling.

In the case of the production of an isotropic sheet of electrical steel during a complete redistribution, the cold-rolled sheet is annealed at a high temperature in the range of 700-1050 ^o C for less than 10 minutes "Consumers" can conduct stress relieving annealing after processing, if necessary, and with a high carbon content decarburization annealing can be performed. This operation can be carried out in the usual manner in a mixed atmosphere of hydrogen and nitrogen.

In the meantime, in the case of half-sheet production of the sheet for a cold-rolled sheet, intermediate annealing is performed at 650-950 ^° C for less than 5 minutes, then calibration rolling is performed with compression of 2.0-15.0% and relaxation annealing to relieve stresses and grain growth , which is held by "consumers" of manufacturers of electric cars. If the intermediate annealed sheet is rolled with compression of less than 2%, the grain does not grow enough, and if compression is performed by more than 15%, the grain becomes finer and the magnetic properties deteriorate. As a result, it is desirable to limit the reduction in thickness during rolling to 2.0–15.0%. An insulating coating can be applied before being sent to “consumers”. Burnishing can be carried out for uncoated steel during heat treatment at "consumers".

 In the case of the manufacture of electrical steel during the complete redistribution, it is desirable to control the process conditions to ensure that the grain size in the microstructure of the steel exceeds 20 μm, preferably has grain sizes of 20-120 μm, most preferably 40-120 μm, and the structural parameter calculated from Hort’s formula should be greater than 0.2, preferably greater than 0.5.

 In the production of the sheet according to the invention by a half process, it is desirable to control the conditions of the production process so that the structure grains are more than 50 microns, preferably 50-250 microns and even more preferably 80-200 microns, and the structural parameter calculated by the Gort formula is greater than 0.2 and preferably greater than 0.5.

The invention further relates to a method for manufacturing an isotropic sheet of electrical steel with improved magnetic properties, in which a steel ingot containing (wt.) Less than 0.02 carbon, less than 3.5 silicon, less than 0.5 manganese, less than 0.15 phosphorus, less 0.015 sulfur, less than 0.7 aluminum, less than 0.005 oxygen, less than 0.008 nitrogen, with a total content of one or both alloying elements of tin and antimony 0.02-0.3% 0.02-1.0 nickel, 0.02-0 , 4% copper, the rest is iron and inevitable impurities, is subjected to hot rolling, and the final rolling is carried out in ferritic phase at a temperature of more than 800 ^o C with a percentage reduction of more than 7%, then the hot-rolled sheet is wound up at a temperature above 600 ^o C, cooled in the air, pickled, one-stage cold rolling or two-stage cold rolling is carried out, followed by high-temperature annealing in the temperature range 700- 1100 ^o C for 10 s 10 minutes

After the steel ingot is placed in a hot rolling heating furnace, rolling is performed. It is possible to re-heat the ingot to 1300 ^o C, but a temperature lower than 1250 ^o C is more desirable, because inclusions of aluminum nitride, manganese sulfide and sulfur compounds of copper can grow up to about 1250 ^o C, and at temperatures above 1300 ^o C they decompose into small, which is detrimental to magnetic properties.

The finish hot rolling temperature is very important. To obtain an isotropic electrotechnical steel sheet with improved magnetic properties, low losses and high magnetic flux density and magnetic permeability, the finish temperature of hot rolling should be in the ferrite phase above 800 ^o C. It is also desirable that the reduction in this case exceeded 7% because the grain is in the ferrite phase easily grows with a final hot reduction of more than 7%
According to this invention, the final practice is carried out with a decrease in the sheet thickness of more than 7% at a temperature above 800 ^o C, but below the point A _r1 in the ferrite phase.

 Then high-temperature annealing is carried out. Magnetic properties improve with small grain growth at the final stage.

 Since the phase transformation does not occur when the silicon content in the steel is higher than 1.5%, the maximum temperature limit of the finish hot rolling can be determined by the heating temperature before rolling.

If hot rolling is carried out with compression less than 7% or at a final temperature less than 800 ^o C, the magnetic properties are reduced, since the grain does not grow sufficiently. In fine hot rolling, the magnetic properties are improved even with a reduction of 50%; therefore, the maximum reduction in thickness is not limited, but taking into account the deformation resistance, it is preferable that the reduction is not more than 50%
After such hot rolling, the sheet is wound onto a roll at a temperature above 600 ^° C and the final grain growth occurs upon cooling in air under normal conditions during winding. If the winding temperature is not higher than 600 ^o C, the grain does not increase sufficiently, and the magnetic properties are reduced.

 It is not necessary to set a maximum limit for the temperature of the coiling process, and the coiling process can be carried out immediately after hot finishing in the ferrite phase.

It is advisable to wind up the roll at a temperature above 600 ^° C, and then slowly cool at a speed of no higher than 30 ^° C for 1 hour in the center of the hot roll. With such slow cooling, it is possible not to anneal the hot rolled sheet.

Even if the hot-rolled sheet is cooled in air, a maximum cooling rate of 30 ^° C per 1 hour can be obtained at an initial air temperature of 25 ^° C. Slow cooling can be obtained by heating the lid or by placing the roll in a closed volume. This method has the advantage of reducing the temperature difference between the hot middle part of the sheet and the edge of the sheet.

 In the case of using a heated cover, it must be heat-resistant, and thermal insulation can be carried out by applying the cover to the hot roll one after another, or to the stack of rolls when cooling. Such a heated lid is used for cooling in air, and the injection of an inert gas, such as nitrogen, under the lid slows down the oxidation of the hot-rolled sheet during cooling. By winding the sheet into a roll according to the described method, after high-temperature annealing, a large final grain growth is obtained.

 Pickling of a hot-rolled sheet wound into a roll and cooled in air in a hydrochloric acid solution removes scale from its surface. The pickled hot rolled sheet is cold rolled in one or two stages.

The finished sheet after cold rolling is subjected to high-temperature annealing after removing the grease used in the laying with an alkaline solution. The temperature of high-temperature annealing depends on the silicon content, but it is desirable to carry out high-temperature annealing in the range of 700-1100 ^o C for a time of 10 s to 10 min, since the grain does not increase sufficiently during the annealing, if the temperature does not exceed 700 ^o C or the annealing time is less 10 s, and the magnetic properties deteriorate due to excessive oxidation if the annealing temperature is greater than 1100 ^o C or the annealing time exceeds 10 minutes

 In the case of manufacturing non-oriented electrical steel sheet according to the method described above, it is desirable to control the production process so that the grain in the sheet has a size of more than 25 microns, preferably in the range of 25-200 microns, and most preferably in the range of 30-150 microns, and the structural parameter is was greater than 0.2, preferably greater than 0.5.

 This invention relates to a method for manufacturing an isotropic electrical steel sheet with enhanced magnetic properties in a complete redistribution process, in which a steel ingot containing, by weight. carbon less than 0.02; silicon less than 3.5; manganese less than 0.5; phosphorus less than 0.15; sulfur less than 0.01; nitrogen less than 0.008; aluminum less than 0.7; nickel 0.02-1.0; copper 0.02-0.5, with a total content of one or both alloying elements - tin and antimony 0.02-0.2% 0.001-0.02% calcium and / or 0.003-0.3% rare earth element, the rest is iron and unavoidable impurities, it is hot rolled, coiled, etched after hot rolling or after annealing of the hot rolled sheet, then it is cold rolled in one or two stages and then subjected to high temperature annealing or in a half process in which a steel ingot of the specified composition is hot rolled, poison the last e rolling or after annealing, is subjected to cold rolling in one step, conduct intermediate annealing and calibration rolling.

 In the described manufacturing method according to the invention, by adding more than one calcium alloying element in an amount of 0.001-0.02% or a rare earth element in an amount of 0.003-0.03% to one or both of the alloying elements, tin and antimony, independently or in combination with a component system containing nickel and copper inhibit the formation of inclusions such as manganese sulfide, harmful to magnetic properties. Crystalline grain grows and a structure favorable for magnetic properties is formed. Since calcium and the rare-earth element also cause the formation of impurities, which is also sufficient for the production of pure steel, the grain easily grows during high-temperature annealing after cold rolling, the structure of the (111) plane, which impairs the magnetic properties, is suppressed around the inclusions, a structure favorable for magnetic properties develops well , and accordingly the magnetic properties are improved.

 In the steelmaking process, alloying elements are introduced before continuous casting, hardening of the slab or manufacturing of the ingot. Calcium is administered before or during degassing. When a rare-earth element is introduced during degassing or continuous casting, the actual yield increases. Other alloying elements can be introduced at any stage from the start of steelmaking to degassing.

The steel ingot obtained as described is loaded into a heating furnace, heated and held before hot rolling and then subjected to hot rolling. There is no problem with hot rolling if the final rolling temperature is above 750 ^o C. It is advisable to wind the rolled sheet at a temperature above 500 ^o C to get a finished hot rolled sheet. After etching, such a sheet is cold rolled to a final thickness. Before pickling, the hot rolled sheet may be annealed in a continuous process or in a container. Due to this annealing, the magnetic properties are further improved. It is advisable to anneal at a temperature above 700 ^o C.

This hot rolled sheet can be cold rolled in one step. Intermediate annealing can be carried out in the temperature range of 700-1100 ^o C, then the second stage of cold rolling can be carried out. In the case of manufacturing an electrical sheet by the complete process, it is desirable to conduct high-temperature annealing in the temperature range of 700-1100 ^o C on a sheet wound into a roll.

 Also, in the case of the half-process manufacturing of the electrical sheet, the cold rolling of the second stage can be crimped with less than 15% and the products are sent to the “consumer” without high-temperature annealing, and annealing with stress relieving can be carried out after processing by the “consumer” by the manufacturer of electric machines.

 The final product is sent to "consumers" after coating in the form of an insulation layer on steel.

 In the case of manufacturing a sheet by the complete process, it is desirable to control the manufacturing process so that the crystalline grain in the sheet is at least 30 microns in size, preferably in the range of 30-200 microns and even better 50-150 microns, and the structural coefficient calculated by the Gort formula would be greater than 0.2, preferably greater than 0.5.

The invention further relates to a method for manufacturing an isotropic electrical sheet with enhanced magnetic properties by a complete process, in which a steel ingot containing, by weight. carbon 0.02-0.06; silicon less than 3.5; manganese less than 0.5; phosphorus less than 0.15; sulfur less than 0.01; nitrogen less than 0.008; aluminum less than 0.7; oxygen is less than 0.005, the total content of one or both of the alloying elements of tin and antimony is 0.02-0.2% 0.02-1.0% nickel, 0.02-0.5% copper, the remaining iron and inevitable impurities are exposed to hot rolling, pickling, then cold rolling in one or two stages, decarburizing annealing of the cold rolled sheet in the temperature range 750-900 ^o C in a mixed atmosphere of 60-90% nitrogen and 40-10% hydrogen with dew point: 30-60 ^o C, and then the final annealing, or half process, in which the initial ingot of this composition is subjected to hot rolling, pickling NIJ, is cold rolled in one step, and then to intermediate annealing gauge and rolling, as well as relaxation stress relief is carried out "consumers".

 In the proposed manufacturing method, the structure is improved and, consequently, the magnetic permeability is increased due to decarburization annealing, since, as you know, carbon is an element that degrades magnetic properties due to a decrease in grain size in the final sheet material.

After placing the steel sheet described above in a heating furnace and hot rolling it is advisable to wind the sheet into a roll at a temperature above 500 ^o C. The ingot can be heated up to 1250 ^o C.

 The hot rolled sheet, as described, can be cold rolled after pickling without annealing. Also, cold rolling can be carried out after annealing and pickling.

The hot-rolled sheet can be annealed continuously or in a container, and it is desirable to anneal in the temperature range of 700-1100 ^° C for 10 s 20 minutes with continuous annealing or in the temperature range of 600-1000 ^° C for 30 minutes 10 hours during annealing in the container. Annealing in a container during prolonged annealing for hours can be carried out in a non-oxidizing atmosphere of nitrogen and other gases to prevent surface oxidation.

In the case of manufacturing an isotropic electrical steel sheet in a complete process, one-stage cold rolling is performed, or first-order rolling with intermediate annealing, usually at 700-1000 ^o C, or double-rolling or second-order rolling, when the cold-rolled sheet is subjected to high-temperature annealing after decarburization annealing. It is desirable to carry out decarburization annealing according to the continuous annealing method in the temperature range of 750-900 ^o C in an atmosphere of 60-90% nitrogen and 40-10% hydrogen with a dew point: 30-60 ^o C for 1-10 minutes. When carrying out such decarburization, it will be insufficient if the content of nitrogen and hydrogen in the atmosphere is too large or small. The residual carbon content after decarburization becomes greater if the dew point is too high or too low.

It is desirable to carry out such high-temperature annealing at 700-1100 ^o C for less than 10 min, because with increasing time, at a temperature not exceeding 700 ^o C, a deep layer of oxides appears on the surface of the sheet, due to which the magnetic properties decrease, or if the annealing temperature above 1100 ^o C.

In the case of manufacturing a non-oriented electrical steel sheet according to the half-process, cold rolling of the first-order sheet is carried out, intermediate annealing at 650-950 ^o C for a period of not more than 10 minutes, and then processing is carried out by “consumers” calibration with compression of 2-15% During the intermediate annealing can also be carried out decarburization. In this case, it is desirable to conduct continuous annealing at 750-900 ^o C for 1-10 minutes in a mixed atmosphere of nitrogen and hydrogen and thus provide decarburization.

In the case of decarburization during such intermediate annealing, it is advisable to anneal in an atmosphere of mixed nitrogen and hydrogen with a dew point of 30-60 ^° C with a nitrogen content of 60-90% and hydrogen of 40-10% since decarburization becomes insufficient if the content of nitrogen and hydrogen too small or too large, and the residual carbon content after decarburization will be too high if the dew point is too low or too high.

Further, decarburization annealing can be carried out in the process of relaxation annealing with stress relieving carried out by the "consumer". In this case, it is desirable to carry out annealing by decarburization during high-temperature annealing with stress relief at 750-850 ^o C in an atmosphere of 60-90% nitrogen and 40-10% hydrogen with a dew point of 30-60 ^o C.

 With such annealing, decarburization becomes ineffective if the nitrogen and hydrogen content is too small or too high, and the residual carbon content increases if the dew point is too high or too low.

 In the case of manufacturing an isotropic electrical steel sheet by a complete process, it is desirable to control the manufacturing conditions so that the grain size is more than 20 microns, preferably in the range of 20-180 microns and most preferably in the range of 30-150 microns, and the structural parameter with the Hort formula is greater than 0 , 3, and preferably more than 0.5.

 Meanwhile, in the case of manufacturing a steel sheet according to the invention in a half process, it is desirable to control the manufacturing process so that the grain of the structure has a size of more than 50 microns, preferably in the range of 50-250 microns and most preferably in the range of 80-200 microns, and the structural parameter calculated from Hort’s formula would be greater than 0.3, and preferably greater than 0.5.

Example 1. The ingot obtained in the process of cooking steel, composition indicated in the table. 1, was heated to 1200 ^o C, was subjected to hot rolling with the parameters specified in the table. 2 to a thickness of 2.3 mm, wound into a roll, annealed and cold rolled to a thickness of 0.5 mm. The cold-rolled sheet was annealed in an atmosphere of 20% hydrogen and 80% nitrogen for 3 minutes. After relaxation annealing with stress relieving, which was carried out at 790 ^° C in an atmosphere of 100% nitrogen for 2 hours, the magnetic properties were measured. The measurement results are given in table. 2. It can be seen from it that the test results for sheets made according to the invention (1-4) (part II) for steels according to the invention (ad) made with a composition according to the invention and according to the method described in the invention have improved magnetic properties compared to sheets (1-7), part I, obtained by methods known in the art that were made of steel (ae) outside the range of alloying elements according to the invention.

 The results of measuring the grain size of each sample corresponding to the table. 2, the following: samples 1, 2, and 3 had a grain size of 52 μm, 56 μm, and 47 μm, respectively, and comparative samples (4-7) had sizes in the range 56-63 μm. But the products according to the invention (1-4) see part II had a grain size range of 65-98 microns.

 Thus, the sheets obtained according to the invention (1-4) have larger grain sizes than comparative (1-7).

Example 2. As described in the table. 3, the ingot with different copper and tin contents was heated to 1200 ^o C, then the final hot rolling was carried out at 850 ^o C to a sheet thickness of 2.3 mm, the sheet was wound into a roll at 700 ^o C, the hot-rolled sheet was annealed at 800 ^o C within 3 hours. After pickling, the hot-rolled sheet was cold rolled to a thickness of 0.5 mm, and then high-temperature annealing was carried out at 950 ^° C for 2 minutes. After that, the magnetic properties were measured and the measurement results are given in table. 4 together with an assessment of the surface condition of the rolled sheet.

 From the table. 4 shows that the sheets obtained according to the invention (1,2), and the steel obtained according to the invention (a, b), the composition of which is in the claimed range of values, and the steel made according to the method claimed in the invention, have better magnetic characteristics, as well as a satisfactory surface condition after cold rolling compared with a comparative sheet (1) of a comparative steel grade (a), which differs in the content of components from the range containing the steel components according to the invention.

Example 3. Steel ingot, wt. carbon 0.006; silicon 2.95; manganese 0.35; phosphorus 0.03; sulfur 0.005; 0.28 aluminum; nitrogen 0.003; tin 0.11; nickel 0.25; 0.16 copper was heated to 1200 ^° C and subjected to hot rolling to a thickness of 2 mm at a final rolling temperature of 900 ^° C in the ferritic phase, rolled up at 700 ^° C, and the hot-rolled sheet was annealed under the conditions indicated in the table. 5, then it was pickled and subjected to first-order cold rolling to a thickness of 1.0 mm, then intermediate annealing was carried out at 900 ^° C for 2 minutes, then second-order cold rolling to a thickness of 0.5 mm with a percentage reduction of 50% and then double cold rolling. Then, the sheet that was finally cold rolled was subjected to high-temperature annealing at 1050 ^° C for 3 min, then it was cut and subjected to relaxation annealing to relieve stresses at 790 ^° C for 2 hours. After that, the magnetic properties were measured, and the results are summarized in Table 1. 5.

 As shown in the table. 5, the sheets according to the invention (a-c), annealed according to the proposed method, have increased magnetic properties compared with comparative (a), where the annealing was carried out under conditions different from the invention.

 As stated above, the invention is effective in improving the efficiency of electrical products and saving energy by using an isotropic electrical steel sheet having lower losses and high magnetic flux density and permeability.

Example 4. Each test sample was made in half process, in which the steel ingot had the composition shown in table. 6. It was heated to 1210 ^o C, underwent hot rolling in the conditions of the table. 7, rolled up, annealed, passed cold rolling, intermediate annealing, calibration rolling and heat treatment by the "consumer". The final thickness of the sample was 0.47 mm, and annealing was carried out in a nitrogen atmosphere.

 Magnetic properties were measured on the test samples, the measurement results are presented as averaged values in the rolling direction and in the direction opposite to the rolling direction.

 From the table. 7 shows that the sample according to the invention (1) has better magnetic properties compared with comparative samples (1-4), which were made of comparative steel (a) without copper, comparative steel (b) with a content of 0.8% manganese, comparative steel (c) with a content of 1.1% silicon and 0.55% manganese and 0.002% oxygen and comparative steel (d) with a content of 1.25% manganese.

Example 5. Steel ingot composition shown in table. 8, was heated to 1200 ^o C and subjected to hot rolling in the conditions of table. 9, was rolled up and pickled, then cold rolled and then annealed. The atmosphere during annealing of the cold-rolled sheet consisted of 20% hydrogen and 80% nitrogen. Then, relaxation annealing was performed with stress relieving at 790 ^° C in an atmosphere of pure nitrogen for 2 hours, magnetic properties were measured, and the measurement results are summarized in Table 9. The magnetic properties indicated in the table. 9 were measured under the conditions listed in Table 7 of Example 4.

 As can be seen from the table. 9, the samples according to the invention (1-5) have better characteristics compared to comparative samples 1 and 2, having the same composition as the samples according to the invention, but differing in the manufacturing conditions from this invention.

Example 6. Steel ingot according to the invention (s) from table. 8 of example 5 was heated to 1200 ^o C, was subjected to hot rolling under the conditions of the table. 10, rolled up, pickled, cold rolled. The cold-rolled sheet was annealed in an atmosphere of hydrogen and nitrogen. The cold-rolled sheet was annealed and cut and then annealed at 790 ^° C in an atmosphere of 20% hydrogen and 80% nitrogen for 2 hours. After that, the magnetic properties were measured, and the measurement results are summarized in table. 10.

 The conditions for measuring magnetic properties are the same as shown in table 7 of example 4.

 As can be seen from the table. 10, the sheets according to the invention (1-4) made of steel according to the invention (c) at the same final temperature of hot rolling and the temperature of reeling in a coil and the conditions of annealing of the cold rolled sheet and when the conditions of annealing of the hot rolled sheet are changed in the range of the invention have improved magnetic properties.

 Example 7. Steel ingot composition, wt. carbon 0.003; silicon 0.52; manganese 0.15; phosphorus 0.06; sulfur 0.004; 0.30 aluminum; nitrogen 0.002; oxygen 0.003; nickel 0.35; copper 0.21; tin 0.11 and iron the rest was heated and processed in half process, as shown in table. eleven.

The intermediate annealing of the cold-rolled sheet was carried out in a mixed atmosphere of hydrogen and nitrogen, then calibration rolling and heat treatment were carried out at 790 ^° C in a nitrogen atmosphere for 2 hours, simulating processing by "consumers". Each test sample made by the described method was measured by magnetic properties and the results are summarized in table. 11, the measurements were carried out under the conditions of table 7 of example 4.

 As can be seen from the table. 11, half-process samples of the invention (1-5) have improved magnetic properties compared to comparative sample (1) in which the final hot rolling was carried out in the austenitic phase.

Example 8. Steel ingot composition, wt. carbon 0.005; silicon 0.85; manganese 0.25; phosphorus 0.06; sulfur 0.005; 0.35 aluminum; nitrogen 0.02; nickel 0.25; copper 0.17; tin 0.21, iron the rest was heated to 1230 ^o C and the hot-rolled sheet was processed under the conditions of the final rolling temperature and roll temperature indicated in the table. 12.

In this steel, the temperature of the transition point A _{r1, the} maximum temperature corresponding to the ferrite phase was 910 ^° C and the thickness of the hot-rolled sheet was 2 mm. After this, the sheet was rolled up in air and etched in a HCl solution. The measurement of the point A _r1 was carried out by a device that measures electrical resistance. In the case of using a heating lid for winding and cooling a hot-rolled sheet, the cooling rate was 5-10 ^° C for 1 h to the initial room temperature of 25 ^° C. Then, the hot-rolled sheet was subjected to single-stage cold rolling to a thickness of 0.50 mm.

Rolled grease was removed from the cold-rolled sheet by using an alkali solution, and high-temperature annealing was carried out at the temperature indicated in the table. 12. The high-temperature annealing time was 2 min, and the atmosphere consisted of 30% hydrogen and 70% nitrogen. The residual carbon content after high temperature annealing is 0.003%
The annealed sheet was cut after applying an insulating coating of mixed organic and inorganic combined material, and stress-relieving annealing was carried out at 800 ^° C for 2 hours. After that, the magnetic properties and size of the crystalline grain were measured and the results are listed in Table 1. 12. The grain size was determined by the method of straight line segments.

As can be seen from the table. 12, the sheets of the invention (1-4) have a grain size of 85-98 μm and increased magnetic properties, while the comparative sheet (1) was hot rolled in the ferrite phase, but the temperature of the end of the hot rolling and the temperature of the coiling were low, as and final compression, due to which the magnetic properties have decreased, and when the comparative sheet (2) has a small compression in thickness, but is hot rolled at a temperature above the transition point A _{r1 of the} boundary point of the 100% ferritic phase, the grain growth is small and the magnetic properties deteriorate.

Example 9. Steel ingot with a content, wt. carbon 0.003; silicon 1.1; manganese 0.20; phosphorus 0.06; sulfur 0.03; 0.35 aluminum; nitrogen 0.002; tin 0.11; antimony 0.05; nickel 0.09; copper 0.21 and the iron residue was heated to 1150 ^o C and processed by the complete process, as shown in the table. thirteen.

In this steel, the boundary temperature of the ferritic phase A _r1 was 940 ^° C, and hot rolling with a final reduction in thickness of 30% was carried out to obtain a sheet with a thickness of 2.3 mm. Hot rolled sheet with the final temperature indicated in the table. 13, rolled up and cooled, then pickled in an acid solution. The sheets obtained according to the invention (5) and (6) in table. 13, which were cooled under a lid, rolled up and cooled in a nitrogen atmosphere. The cooling rate was 10-15 ^o C in 1 h, and the comparative sheet (3) was wound and cooled in air.

As for the etched hot-rolled sheet, then first-order cold rolling was carried out to 1 mm and intermediate annealing was carried out at 900 ^° C in a mixed atmosphere of hydrogen and nitrogen for 2 minutes. After intermediate annealing, cold rolling to 0.47 mm was carried out and high-temperature annealing was carried out under the conditions shown in Table. 13. High-temperature annealing was carried out in a drying atmosphere of 40% hydrogen and 60% nitrogen.

The annealed sheet was cut after applying an insulating coating and annealing was carried out with stress relief at 820 ^° C in a dry atmosphere of 100% nitrogen for 90 minutes. After that, the magnetic properties and grain size were measured and the results are summarized in table. thirteen.

 As can be seen from the table. 13, the sheets of the invention (5) and (6) have sufficiently grown grain and increased magnetic properties, while the comparative sheet (3) has insufficiently grown grain due to the low temperature when being rolled up and the short time of high temperature annealing, resulting in magnetic properties are declining.

 Example 10. Steel ingot composition indicated in the table. 14, was made with the addition of calcium or a rare-earth element to the melt during steel production. The rare-earth element (REE) in steel (b) according to the invention was neodymium, and the REE of steel (d) according to the invention was cerium.

The steel ingot was heated to 1210 ^° C, hot rolled at a final temperature of 870 ^° C to a thickness of 2.0 mm and the sheet was rolled up at 720 ^° C, the hot-rolled sheet was annealed at 900 ^° C for 5 minutes, then the sheet was etched and subjected to cold rolling to a thickness of 0.47 mm Then this sheet was subjected to high-temperature annealing in an atmosphere of mixed gases of 20% hydrogen, and 80% nitrogen under the conditions noted in table. 15. But for the sample (4) according to the invention in table. 15 hot-rolled sheet did not anneal. After high-temperature annealing of a cold-rolled sheet, it was cut and annealed with stress relief at 800 ^° C for 1.5 h. After that, the magnetic properties were measured and the thickness of the plane (III), which is unfavorable for the magnetic properties in the structure, was studied. The results are summarized in table. 15. Measurements of magnetic properties for the table. 15 were carried out using the instrument for measuring on one sheet.

 As can be seen from table 15, for samples corresponding to the invention (1-5), the structural coefficients of the plane (III), which are unfavorable for magnetic properties, are low, as a result of which the magnetic properties are higher than for comparative sample (1).

Example 11. Steel ingot composition, wt. carbon 0.003; silicon 2.2; manganese 0.35; phosphorus 0.04; sulfur 0.002; aluminum 0.3; nitrogen 0.002; tin 0.15; nickel 0.25; copper 0.13; calcium 0.009; the rest of the iron was heated to 1140 ^o C, hot rolled to a final temperature of 850 ^o C and a thickness of 2 mm and was wound into a roll at 720 ^o C.

The hot-rolled sheet wound into a roll was annealed in a container at 900 ^° C for 2 hours, then pickled and the first stage of cold rolling was carried out to a thickness of 1 mm, then intermediate annealing was performed at 900 ^° C for 3 minutes, then the second stage of cold rolling was carried out to a thickness of 0.5 mm and then the finished cold-rolled sheet was produced by a two-stage method of cold rolling.

High-temperature annealing was carried out at 1000 ^o C in an atmosphere of 30% hydrogen and 70% nitrogen for 3 min, as well as sheet cutting, and magnetic properties were measured on samples from one sheet after annealing with stress relief at 790 ^o C. The measurement results were summarized in table 16. The measurements showed that the grain size was 105 μm, and the structure parameter according to the Gort formula was 0.57.

 As can be seen from the table. 16, a non-oriented electrical steel sheet manufactured by the method of the invention has low power losses and high magnetic flux density and magnetic permeability.

Example 12. A steel ingot of the composition shown in table 17, obtained in the steelmaking process, was heated to 1200 ^o C and hot rolling was carried out to a final temperature of 850 ^o C and a thickness of 2.0 mm, then the sheet was rolled into a roll at 600 ^o C The hot rolled sheet was etched under the conditions shown in the table. 18, with or without annealing, and then cold rolling was carried out to a thickness of 0.5 mm. When annealing was carried out in the container, the oxidation of the surface of the hot-rolled sheet was suppressed by a 100% nitrogen atmosphere. Continuous annealing was carried out in an atmosphere of air.

Regarding the aforementioned cold-rolled sheet, annealing was carried out in an atmosphere of a mixture of gases of 30% hydrogen and 70% nitrogen with a dew point of 40 ^° C. for 3 minutes, as described in Table 18, and then high-temperature annealing was carried out.

 High-temperature annealing was carried out in an atmosphere of 20% hydrogen and 80% nitrogen for 3 min after high-temperature annealing and cutting of the annealed sheet, the magnetic permeability was measured, and the measured results are listed in Table 18.

 From the table. 18 it can be seen that the samples obtained according to the invention (1-9), made from steels made according to the invention (a, b, c) having a range of element content in accordance with the invention, and in the production conditions corresponding to the invention, have a higher magnetic permeability compared with comparative samples (1-8), differing in the content of elements in steel and / or manufacturing conditions from this invention.

For samples (1-3) obtained according to the invention (see table. 18), the structure was studied. Observations showed that the structural coefficient of the (110) and (200) planes was in the range 1.2-1.7, and the study of the structure for comparative samples (6, 7) showed that these coefficients are in the range 0.6-1, 0. Here, the structural index is the structural coefficient from the Gort formula. The results of monitoring the residual carbon content after decarburization annealing showed that in the samples according to the invention (1-9), the residual carbon content was in the range of 0.001-0.003%
Example 15. The steel composition shown in table 19, was heated to 1230 ^o C, hot rolling was completed at 850 ^o C. The sheet was rolled up at 750 ^o C.

 After processing the hot-rolled sheet under the conditions shown in Table 20, the magnetic permeability was measured and typical measurement results are shown in Table 20.

 Samples are given in table. 20, were manufactured in a complete process.

Samples corresponding to the invention (1-3) underwent decarburization annealing of a cold-rolled sheet at an appropriate temperature in an atmosphere of 20% hydrogen and 80% nitrogen with a dew point of 45 ^° C for 4 minutes, and high-temperature annealing was carried out at appropriate temperatures in an atmosphere of 30% hydrogen and 70% nitrogen for 3 minutes. Comparative samples (1) and (2) passed decarburization annealing in a furnace with an atmosphere of 50% hydrogen and 50% nitrogen with a dew point of 80 ^o C.

For comparative sample (2), the residual carbon content was 0.006%, and for sample (2) according to the invention, 0.0023%
Comparative samples (3-4) and samples obtained according to the invention (4-6), were made by a half process. For the comparative sample (3) and the sample obtained according to the invention (4-5), decarburization annealing was carried out at appropriate temperatures in a mixed atmosphere of 70% nitrogen and 30% hydrogen with a dew point of 40 ^o C for 2 hours. stress relieving after intermediate annealing was cooled in a furnace. For comparative sample (4), decarburization annealing was carried out in a mixed atmosphere of 40% nitrogen and 60% hydrogen with a dew point of 10 ^° C for 2 hours. For comparative sample (6), decarburization annealing was carried out in an atmosphere of 20% nitrogen and 80% hydrogen. with a dew point of 45 ^o C during intermediate annealing.

 It turned out that decarburization annealing can be carried out during intermediate annealing and during annealing with stress relieving.

 As can be seen from the table. 20, the samples made according to the invention (1-6), with the claimed range of contents and manufacturing conditions, have increased magnetic permeability compared to comparative samples (1-6), which have the same range of element contents as the samples according to the invention, but rejected by the conditions of manufacture.

 Further, the comparative samples (3.4) obtained by the half-process have respectively a grain size of 80 μm and 75 μm and a structural parameter of 0.4 and 0.25, respectively. And sample 4 according to the invention has a grain size of 120 μm and a structural parameter of 0.68.

 The sample according to the invention (1), obtained by the complete process, has a grain size of 75 μm and a structural parameter of 0.5.

Claims (11)

 1. A sheet of isotropic electrical steel containing carbon, silicon, manganese, phosphorus, sulfur, nitrogen, aluminum, nickel, copper and iron, characterized in that the steel further comprises tin and / or antimony in the following ratio of components, wt. Carbon Less than 0.02
Silicon 1.0 3.5
Manganese Less than 1
Phosphorus Less than 0.1
Sulfur Less than 0.01
Nitrogen Less than 0.008
Aluminum Less than 0.7
Nickel 0.05 1.0
Copper 0.02 0.5
Tin and / or antimony 0.02 0.2
Iron Else
2. A sheet of isotropic electrical steel containing carbon, silicon manganese, phosphorus, sulfur, nitrogen, oxygen and iron, characterized in that the steel further comprises aluminum, nickel, copper, and also tin and / or antimony in the following ratio of components, wt. Carbon Less than 0.02
Silicon Less than 1
Manganese Less than 0.5
Phosphorus Less than 0.15
Sulfur Less than 0.01
Nitrogen Less than 0.008
Oxygen Less than 0.005
Aluminum Less than 0.7
Nickel 0.05 1.0
Copper 0.02 0.5
Tin and / or antimony 0.02 0.2
Iron Else
3. A sheet of isotropic electrical steel containing carbon, silicon, manganese, phosphorus, sulfur, nitrogen, aluminum, nickel, copper and iron, characterized in that the steel additionally contains oxygen, as well as tin and / or antimony in the following ratio of components wt. Carbon Less than 0.02
Silicon Less than 3.5
Manganese Less than 0.5
Phosphorus Less than 0.15
Sulfur Less than 0.015
Aluminum Less than 0.7
Oxygen Less than 0.005
Nitrogen Less than 0.008
Nickel 0.02 1.0
Copper 0.02 0.4
Tin and / or antimony 0.02 0.3
Iron Else
4. A sheet of isotropic electrical steel containing carbon, silicon, manganese, phosphorus, sulfur, nitrogen, aluminum, nickel, copper and iron, characterized in that the steel further comprises tin and / or antimony and calcium and / or rare earth in the following ratio components, wt. Carbon Less than 0.02
Silicon Less than 3.5
Manganese Less than 0.5
Phosphorus Less than 0.15
Sulfur Less than 0.01
Nitrogen Less than 0.008
Aluminum Less than 0.7
Nickel 0.02 1.0
Copper 0.02 0.5
Tin and / or antimony 0.02 0.2
Calcium 0.001 0.02
and / or
Rare earth element 0.003 0.03
Iron Else
5. A sheet of isotropic electrical steel containing carbon, silicon, manganese, phosphorus, sulfur, nitrogen, aluminum, nickel, copper and iron, characterized in that the steel additionally contains oxygen, as well as tin and / or antimony in the following ratio of components, wt . Carbon 0.02 0.06
Silicon Less than 3.5
Manganese Less than 0.5
Phosphorus Less than 0.15
Sulfur Less than 0.01
Nitrogen Less than 0.008
Aluminum Less than 0.7
Oxygen Less than 0.005
Nickel 0.02 1.0
Copper 0.02 0.5
Tin and / or antimony 0.02 0.2
Iron Else
6. A method of obtaining a sheet of isotropic electrical steel, including the smelting of a steel slab, hot rolling, pickling, single or double cold rolling and high temperature annealing, characterized in that the steel slab is melted, containing, by weight. Carbon Less than 0.02
Silicon 1.0 3.5
Manganese Less than 1
Phosphorus Less than 0.1
Sulfur Less than 0.01
Nitrogen Less than 0.008
Aluminum Less than 0.7
Nickel 0.05 1.0
Copper 0.02 0.5
Tin and / or antimony 0.02 0.2
Iron Else
and the sheet obtained after hot rolling is annealed before etching, and after high-temperature annealing, if necessary, a stress-free vacation is carried out. 7. The method according to claim 6, characterized in that before etching, a continuous annealing of the hot-rolled sheet is carried out at 700 1000 ^o C for a time from 10 s to 20 minutes  8. A method of obtaining a sheet of isotropic electrical steel, including hot rolling of a steel slab, etching, cold rolling, intermediate annealing and final annealing, characterized in that the hot rolling is subjected to a slab of steel containing, by weight. Carbon Less than 0.02
Silicon Less than 1
Manganese Less than 0.5
Phosphorus Less than 0.15
Sulfur Less than 0.01
Nitrogen Less than 0.008
Oxygen Less than 0.005
Aluminum Less than 0.7
Nickel 0.05 1.0
Copper 0.02 0.5
Tin and / or antimony 0.02 0.2
Iron Else
and the sheet obtained after hot rolling is annealed before etching, and after intermediate annealing, the sheet is trained. 9. The method according to claim 8, characterized in that the finish hot rolling is completed in the temperature range from 750 ^o C to the temperature of the transition point Ar ₁ in the ferrite phase. 10. The method according to p. 8, characterized in that before etching conduct continuous annealing of the hot-rolled sheet at 700 1000 ^o C for a time from 10 s to 20 minutes  11. A method of producing a sheet of isotropic electrical steel, including the smelting of a steel slab, hot rolling, pickling, cold rolling and final annealing, characterized in that the slab is smelted of steel containing, by weight. Carbon Less than 0.02
Silicon Less than 1
Manganese Less than 0.5
Phosphorus Less than 0.15
Sulfur Less than 0.01
Nitrogen Less than 0.008
Oxygen Less than 0.005
Aluminum Less than 0.7
Nickel 0.05 1.0
Copper 0.02 0.5
Tin and / or antimony 0.02 0.2
Iron Else
and the sheet obtained after hot rolling is annealed before etching. 12. The method according to claim 11, characterized in that the final hot rolling is completed in the temperature range from 750 ^o C to the temperature of the transition point Ar ₁ in the ferritic phase. 13. The method according to p. 11, characterized in that the annealing of the hot-rolled sheet is carried out continuously at 700 1000 ^o C for a time from 10 s to 20 minutes  14. A method of obtaining a sheet of isotropic electrical steel, including the smelting of a steel slab, hot rolling, etching, single or double cold rolling and high-temperature annealing, characterized in that the slab of steel containing, by weight. Carbon Less than 0.02
Silicon Less than 3.5
Manganese Less than 0.5
Phosphorus Less than 0.15
Sulfur Less than 0.01
Nitrogen Less than 0.008
Aluminum Less than 0.7
Nickel 0.02 1.0
Copper 0.02 0.5
Calcium 0.001 0.02
and / or
Rare earth element 0.003 0.03
Iron Else
and after hot rolling, the resulting sheet is rolled up and annealed either before or after etching.  15. A method of obtaining a sheet of isotropic electrical steel, including hot rolling of a steel slab, etching and annealing, characterized in that the hot rolling is subjected to a slab of steel containing, by weight. Carbon Less than 0.02
Silicon Less than 3.5
Manganese Less than 0.5
Phosphorus Less than 0.15
Sulfur Less than 0.01
Nitrogen Less than 0.008
Aluminum Less than 0.7
Nickel 0.02 1.0
Copper 0.02 0.5
Tin and / or antimony 0.02 0.2
Calcium 0.001 0.02
and / or
Rare earth element 0.003 0.03
Iron Else
after hot rolling, the resulting sheet is rolled up and annealed either before or after etching, then first-order annealing and sheet training with intermediate annealing are performed.  16. A method of obtaining a sheet of isotropic electrical steel, including the smelting of a steel slab, hot rolling, pickling, single or double cold rolling, decarburization annealing and high temperature annealing, characterized in that the slab is smelted of steel containing, by weight. Carbon 0.02 0.06
Silicon Less than 3.5
Manganese Less than 0.5
Phosphorus Less than 0.15
Sulfur Less than 0.01
Nitrogen Less than 0.008
Aluminum Less than 0.7
Oxygen Less than 0.005
Tin and / or antimony 0.02 0.2
Nickel 0.02 1.0
Copper 0.02 0.5
Iron Else
and decarburization annealing is carried out at 750 900 ^o C in an atmosphere containing 60 to 90 vol. nitrogen and 40 to 60 vol. hydrogen with a dew point temperature of 30 60 ^o C.

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