CN110643891B - Non-oriented electrical steel plate with excellent magnetic property and manufacturing method thereof - Google Patents
Non-oriented electrical steel plate with excellent magnetic property and manufacturing method thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
- C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
- C21D8/1222—Hot rolling
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
Abstract
The invention discloses a non-oriented electrical steel plate with excellent magnetic property, which comprises the following chemical elements in percentage by mass: c is more than 0 and less than or equal to 0.005 percent, Si: 0.1-1.2%, Mn: 0.1-1.0%, S: 0.008-0.020%, Al: 0.1 to 0.4%, Cu: 0.01-0.05%, more than 0 and less than or equal to 0.003% of N, less than or equal to 0.002% of Ti, and the balance of Fe and other inevitable impurities. The present invention also discloses a method for manufacturing the non-oriented electrical steel sheet having excellent magnetic properties, comprising the steps of: (1) preparing a continuous casting billet; (2) hot rolling; (3) acid washing and continuous rolling; (4) continuous annealing; (5) and (4) coating an insulating coating. The non-oriented electrical steel plate with excellent magnetic property has low cost and excellent magnetic property.
Description
Technical Field
The present invention relates to an electrical steel sheet and a method for manufacturing the same, and more particularly, to a non-oriented electrical steel sheet and a method for manufacturing the same.
Background
With the increasing market demand of users and the increasing demands for high efficiency, energy saving and environmental protection, non-oriented electrical steel products are required to have lower iron loss values and higher magnetic induction values, and the premise is that sufficiently high price competitive advantages are still maintained. In particular, in recent years, the strength of domestic and foreign electrical steel product production enterprises is continuously improved, and the quality of the same variety of real objects of different manufacturers is obviously improved and gradually tends to be consistent. Under the condition, the optimization of the production process is effectively carried out, so that the effective reduction of the manufacturing cost of the product and the stability of the product quality are ensured, and the method has very important practical significance.
In the prior art, because Si and Al elements can obviously improve the resistivity of materials and greatly reduce the iron loss value of finished steel plates, adding a proper amount of Si and Al elements into steel is one of the most effective methods for improving the magnetic performance of finished non-oriented electrical steel plates. In addition, with the increase of the content of Si and Al elements, the inclusions in the steel are gradually refined and increased in number, so that the growth of crystal grains is obviously inhibited, the distortion of crystal lattices is promoted, the movement of magnetic domains is also hindered, the hysteresis loss of a finished steel plate is increased, and the magnetic induction performance is synchronously reduced.
Researchers also find that under the premise that the total amount of Si and Al elements is not changed, the magnetic induction of the finished steel can be improved by increasing the ratio of Al/(Si + Al), but with the increase of the content of the Al element in the steel and the decrease of the content of the Si element, the iron loss value of the finished steel is degraded, and the mechanical property is also reduced.
In the prior art, in order to enable a finished product strip steel to have excellent magnetic induction, Chinese patent documents with patent numbers of CN103014503A, No. 4/3 in 2013 and entitled "high-magnetic-induction low-iron-loss acid-corrosion-resistant non-oriented silicon steel without normalization and production method" disclose that a method of adding 0.20-0.45% of Sn + Cu into steel is adopted, and the texture form of the finished product strip steel is improved by utilizing the principle of grain boundary segregation, so that good material magnetic induction is obtained. However, the elements Sn and Cu are precious metals, which significantly increase the manufacturing cost of steel, and the elements Cu are also liable to cause quality defects on the surface of the strip.
In the prior art, the harmful elements C, S, O, N, Nb, V, Ti and the like in the steel are reduced, and the high furnace outlet temperature, the high finishing temperature and the high coiling temperature in the hot rolling process are matched, so that the hot rolled steel plate with coarse grains can be obtained, the coarsening of inclusions is facilitated, and the good promotion effect on the improvement of the magnetic property of the finished strip steel is achieved. However, this method has disadvantages in that the energy consumption for hot rolling is high, and the stability of the finish rolling process is poor due to the migration of transformation points due to the great increase of the pre-temperature, and the defect of red scale is easily generated at a high coiling temperature.
Currently, the most common means for improving the electromagnetic performance of the finished strip steel in the prior art is to adopt the way of normalizing the middle of the hot rolled steel plate or adopting the way of annealing the middle of the hot rolled steel plate in a bell furnace to obtain favorable texture and coarse grains, so that the electromagnetic performance of the finished strip steel can be well improved. However, this production method will result in a great increase in the manufacturing cost of steel and a reduction in the market competitiveness of the product.
In general, the prior art method for improving the magnetic properties of non-oriented electrical steel sheets increases the manufacturing cost of the steel on the one hand, and puts special requirements on the production process on the other hand, which easily results in increased production difficulty and new surface quality defects.
In view of this, it is desirable to obtain a non-oriented electrical steel sheet which is inexpensive and has excellent magnetic properties.
Disclosure of Invention
An object of the present invention is to provide a non-oriented electrical steel sheet having excellent magnetic properties, which is inexpensive and has excellent magnetic properties.
In order to achieve the above object, the present invention provides a non-oriented electrical steel sheet with excellent magnetic properties, which comprises the following chemical elements by mass percent:
c is more than 0 and less than or equal to 0.005 percent, Si: 0.1-1.2%, Mn: 0.1-1.0%, S: 0.008-0.020%, Al: 0.1 to 0.4%, Cu: 0.01-0.05%, more than 0 and less than or equal to 0.003% of N, less than or equal to 0.002% of Ti, and the balance of Fe and other inevitable impurities.
The design principle of each chemical element in the non-oriented electrical steel plate with excellent magnetic property provided by the invention is as follows:
c: c strongly hinders the growth of finished product crystal grains and is easy to combine with Nb, V and Ti to form fine precipitates, thereby causing the increase of iron loss and the generation of magnetic aging, so the mass percentage of C element in the non-oriented electrical steel plate with excellent magnetic property is limited to be more than 0 and less than or equal to 0.005 percent.
Si: si can improve the resistivity of the matrix and effectively reduce the iron loss of the steel. When the Si content is higher than 1.2%, the magnetic induction of the steel can be obviously reduced; and when the content is less than 0.1%, the effect of effectively reducing the iron loss cannot be achieved. Therefore, the present invention limits the mass percentage of the Si element in the non-oriented electrical steel sheet having excellent magnetic properties to 0.1 to 1.2%.
Mn: mn and S are combined to generate MnS, so that the damage to magnetism can be effectively reduced, the surface state of the electrical steel plate is improved, and hot brittleness is reduced. However, if the Mn content is more than 1.0%, the recrystallized texture is easily broken, and the production cost of steel is greatly increased. Therefore, the present invention limits the mass percentage of Mn element in the non-oriented electrical steel sheet having excellent magnetic properties to 0.1 to 1.0%.
S: the content of S element is designed and Cu is added in the technical scheme2The formation of S inclusions. If the S content is more than 0.020%, MnS and Cu will be added2The S inclusion precipitation is greatly increased, the grain growth is strongly hindered, and the magnetism of the steel is deteriorated. Therefore, the present invention limits the mass percentage of the S element in the non-oriented electrical steel sheet having excellent magnetic properties to 0.008 to 0.020%.
Al: when the Al content is less than 0.1%, a good deoxidation effect cannot be obtained, but when the Al content is more than 0.4%, AlN inclusions are greatly precipitated, the growth of crystal grains is strongly inhibited, and the magnetism of the steel is deteriorated. Therefore, the present invention limits the mass percentage of Al element in the non-oriented electrical steel sheet having excellent magnetic properties to 0.1 to 0.4%.
Cu: the design of Cu element content and Cu in the technical scheme2The formation of S inclusions. When the Cu content exceeds 0.05%, a precipitation phase of Cu is generated to strongly inhibit the growth of crystal grains and deteriorate the magnetic properties of the steel, and when the Cu content is less than 0.01%, a specific sulfur fixation effect is not exhibited in the hot rolling and heat treatment processes. Therefore, the present invention limits the mass percentage of the Cu element in the non-oriented electrical steel sheet having excellent magnetic properties to 0.01 to 0.05%.
N: when the N content exceeds 0.003%, the precipitates of Nb, V, Ti and Al of N are greatly increased, the growth of crystal grains is strongly inhibited, and the magnetic properties of the steel are deteriorated. Therefore, the present invention limits the mass percent of N element in the non-oriented electrical steel sheet with excellent magnetic property to 0 < N < 0.003%.
Ti: when the Ti content exceeds 0.002%, the Ti C, N inclusion is greatly increased, which strongly hinders the growth of crystal grains and deteriorates the magnetic properties of the steel. Therefore, the present invention limits the mass percentage of Ti element in the non-oriented electrical steel sheet with excellent magnetic property to Ti less than or equal to 0.002%.
In the technical scheme of the invention, other inevitable impurities mainly comprise P, and when the content of P exceeds 0.2%, the cold brittleness phenomenon is easily caused, and the cold rolling manufacturability is reduced. Therefore, the present invention limits the mass percentage of the P element in the non-oriented electrical steel sheet with excellent magnetic property to P less than or equal to 0.2%.
It should be noted that, compared with the prior art, the difference of the technical solution is as follows: in the invention, the content of the S element is adjusted consciously in the design process of each element component. In the prior art, it is common to reduce the S content as much as possible in order to reduce the content of harmful inclusions as much as possible. According to the technical scheme, a certain amount of S element is intentionally added, the production process is adjusted, and the harmless treatment of the content of the S element is realized to the maximum extent by controlling the size, the quantity, the type and the morphology of the S compound. Thus, chemical component collocation and combination beneficial to obtaining excellent magnetic performance and reasonable inclusion species control prerequisites are realized, so that the shape, the size and the quantity of the inclusions can be controlled simply, conveniently and efficiently by limiting the cooling rates of different cooling temperature sections in the continuous casting process, and the inclusions are developed towards the direction beneficial to obtaining excellent magnetic performance.
Particularly, when the S content is more than 0.008 percent, the saturation of Mn and S elements is increased and the precipitation time of MnS inclusions is advanced in the continuous casting process, so that the MnS inclusions are easy to polymerize and grow, and the magnetic hazard of the MnS inclusions to finished strip steel is greatly reduced. In addition, in order to further promote the continuous stability of the process, the invention dynamically adjusts the adding amount of Mn according to the S content and ensures that the Mn content is ensured to be in a proper control range so as to ensure that MnS inclusion is precipitated as early as possible in the initial solidification stage of molten steel, so that convenience in temperature and time is provided for the sufficient growth of the subsequent MnS inclusion, and the influence of the MnS inclusion growing to be 0.5 mu m or more on the electromagnetic property of a finished product material is obviously weakened. In addition, when the S content is more than 0.02%, the amount of MnS inclusions is greatly increased and the Cu-S bonding is delayed, i.e., Cu2The precipitation time of S is delayed, and the precipitation size is small and the amount is increased, thereby deteriorating the magnetic performance of the finished strip steel. Therefore, the S content is controlled within the range of 0.008% -0.02%, and the type, the quantity, the size and the appearance of the S compounds in the steel are controlled by matching with the adjustment of the casting process.
In addition, in order to reduce the repeated solid solution and precipitation of MnS precipitates in the hot rolling and heat treatment processes and inhibit the growth of crystal grains, the invention also considers that the lower the content of Mn element is, the MnS and the Cu are under the chemical composition system of the technical scheme2The higher the S composite precipitation ratio. Therefore, the technical scheme adopts a mode of adding a proper amount of Cu into the steel so as to reduce the Mn content in the steel as much as possible. Thereby reducing MnS inclusion precipitation and ensuring the subsequent Cu generation2The S inclusion and the MnS inclusion are compounded and grown, thereby reducing the pinning effect on the crystal grains. Further, Cu produced in this part2Melting Point of S precipitateBelow 600 ℃, can be completely dissolved in a steel matrix under high-temperature annealing, and is precipitated again after high-temperature annealing and grain growth2The S precipitate does not have adverse effect on the electromagnetic performance of the finished strip steel.
Further, the non-oriented electrical steel sheet having excellent magnetic properties according to the present invention has inclusions mainly comprising spherical or spheroidal MnS.
Further, the non-oriented electrical steel sheet having excellent magnetic properties according to the present invention has a very small amount of Cu2S inclusions, very small amount of Cu2The S inclusions are precipitated with the MnS inclusions as a core and are aggregated around the MnS inclusions.
Further, in the non-oriented electrical steel sheet having excellent magnetic properties according to the present invention, the number of grains of 10 μm or more accounts for 65% to 85% of the total number of grains, and the number of grains of 10 μm to 30 μm accounts for 50% to 70% of the total number of grains.
In the technical scheme of the invention, in order to ensure that a good iron loss value is obtained, the number of the crystal grains with the diameter of more than 10 microns in the non-oriented electrical steel sheet with excellent magnetic performance is controlled to be 65-85% of the total number of the crystal grains, so that the hysteresis loss in the iron loss value is reduced as much as possible. In order to ensure that a good magnetic induction value is obtained, the number of the grains of 10-30 μm in the non-oriented electrical steel sheet with excellent magnetic performance is controlled to be 50-70% of the total number of the grains, so that a texture proportion favorable for magnetic induction is obtained as much as possible.
Further, in the non-oriented electrical steel sheet having excellent magnetic properties according to the present invention, Mn and Cu elements satisfy: [ Mn ]]/[Cu]2300-1500, wherein Mn and Cu both represent the values of the two elements without percentage numbers.
Further, the non-oriented electrical steel sheet having excellent magnetic properties according to the present invention has an iron loss P15/50Less than or equal to 4.5W/kg, and magnetic induction B50≥1.745T。
Accordingly, another object of the present invention is to provide a method for manufacturing the above-mentioned non-oriented electrical steel sheet having excellent magnetic properties, which is inexpensive, simple and easy to handle, does not require a normalizing process or a bell type furnace intermediate annealing, and has excellent magnetic properties.
In order to achieve the above object, the present invention provides a method for manufacturing the non-oriented electrical steel sheet having excellent magnetic properties, comprising the steps of:
(1) preparing a continuous casting billet;
(2) hot rolling;
(3) acid washing and continuous rolling;
(4) continuous annealing;
(5) and (4) coating an insulating coating.
In the above manufacturing method, in the step (1), in some embodiments, a continuous cast slab is manufactured after molten iron pretreatment, converter smelting, molten steel vacuum circulation degassing (RH) refining, and continuous casting.
Further, in the manufacturing method of the invention, in the step (1), in the continuous casting and solidification process, the cooling rate of the continuous casting blank is controlled to be less than or equal to 10 ℃/min within the temperature range of 1100-1300 ℃, and the cooling rate of the continuous casting blank is controlled to be 20-40 ℃/min within the temperature range of 600-800 ℃.
In the manufacturing method, in the step (1), in the continuous casting billet cooling process, the cooling rate of the continuous casting billet is controlled to be less than or equal to 10 ℃/min within the temperature range of 1100-1300 ℃ in the continuous casting and solidification process, and the reason that MnS is preferentially precipitated in the cooling rate is mainly considered, so that the relatively low cooling rate is limited, and the purpose is to generate MnS inclusions with coarse sizes as fully as possible, so that the subsequent sulfides with low melting points and small sizes are prevented from being fully precipitated, and the MnS inclusions are easier to coarsen and grow and keep good spherical shapes or spheroidal shapes under the slow cooling condition. The spherical or spheroidal inclusion is not easy to form more harmful wedge-shaped domains, so that the magnetization is easier and the magnetic property is more excellent.
In addition, in the step (1), the continuous casting is carried out at a temperature of 600-800 ℃ in the continuous casting and solidification processThe cooling rate of the blank is limited to 20-40 ℃/min. That is, strong cooling and rapid cooling are required during this period, and the main purpose is to make low melting point Cu2S inclusions not coming to precipitate sufficiently, Cu2The small amount of S inclusion precipitation is advantageous for the control of magnetic properties, and the small amount of Cu capable of precipitation2And S inclusions are precipitated by taking MnS as a core, so that the size of the MnS inclusions is larger and the harm is smaller.
Further, in the manufacturing method of the present invention, in the step (2), the size of the recrystallized structure of the core portion of the obtained hot-rolled strip steel accounts for 60% to 75% of the total size of the hot-rolled strip steel in the thickness direction; wherein the average grain size of the recrystallized structure is between 90 and 140 mu m; the long axis of the crystal grains of the recrystallized structure is consistent with the rolling direction of the strip steel, and the length ratio of the long axis to the short axis is 1.0-1.6.
In the manufacturing method of the present invention, in the step (2), the size of the recrystallized structure of the core portion of the obtained hot rolled strip is controlled to be 60% to 75% of the total size of the hot rolled strip in the thickness direction, wherein the average grain size of the recrystallized structure is between 90 μm and 140 μm, the major axis of the grain of the recrystallized structure is aligned with the rolling direction of the strip, and the length ratio of the major axis to the minor axis is 1.0 to 1.6, so as to reduce the adverse effect on the anisotropy index of the magnetic properties of the non-oriented electrical steel sheet excellent in magnetic properties according to the present invention. The reason why the recrystallization effect of the hot rolled steel sheet is controlled by the present invention is that the quality of the recrystallization effect of the hot rolled structure is inherited. The inventors of the present invention found through studies that the more sufficient the recrystallization effect is in the recrystallized structure of the hot rolled sheet, the larger the crystal grain size is, and the higher the magnetic induction of the finished strip steel is, whereas if the recrystallization effect is worse, the larger the proportion of fine grains or fibrous structures is, and the smaller the crystal grain size is, the lower the magnetic induction of the finished strip steel is, in the recrystallized structure of the hot rolled sheet. In addition, the lower the proportion of fine grains or fibrous structures in the recrystallized structure of the hot rolled plate is, the lower the energy storage in the strip steel is in the cold rolling process, and the growth of crystal grains is not facilitated in the subsequent continuous annealing process, so that the lower iron loss is not easy to obtain.
Further, in the manufacturing method of the invention, in the step (2), the cooling rate of the surface of the strip steel is controlled to be less than or equal to 20 ℃/s in the finish rolling process, and water cooling is performed after the finish rolling is finished to cool the strip steel to the coiling temperature, wherein the time between the finish rolling and the start of the water cooling is 5-20 s, and the coiling temperature is 750-900 ℃.
In the manufacturing method of the present invention, in the step (2), the cooling rate of the surface of the strip is controlled to be not more than 20 ℃/s in the finish rolling process, mainly because the hot rolled strip is thinner and operates at a higher speed unlike the continuous cast slab, and is thus more easily cooled, thereby affecting the recrystallization effect of the hot rolled steel sheet. Therefore, it is necessary to control the cooling rate of the surface of the strip not more than 20 ℃/s, preferably, the cooling rate of the surface of the strip not more than 15 ℃/s, and generally the cooling rate of the surface of the strip not less than 2.5 ℃/s in consideration of the productivity of the hot rolling equipment. Similarly, in order to ensure the high-temperature recrystallization effect of hot rolling, the time between the finish rolling and the start of water cooling is 5 to 20 seconds, and the coiling temperature is 750 to 900 ℃.
Compared with the prior art, the non-oriented electrical steel plate with excellent magnetic property and the manufacturing method thereof have the following beneficial effects:
(1) through reasonable component design, the non-oriented electrical steel plate with excellent magnetic property has low cost and excellent magnetic property.
(2) The method for manufacturing the non-oriented electrical steel plate with excellent magnetic property has the advantages of optimized process design, simplicity and easy operation, no need of normalizing treatment and intermediate annealing in a bell-type furnace, and ensures that the prepared non-oriented electrical steel plate with excellent magnetic property has the iron loss P15/50Less than or equal to 4.5W/kg, and magnetic induction B50≥1.745T。
Drawings
FIG. 1 is a microstructure diagram of a hot-rolled strip steel obtained by passing a non-oriented electrical steel sheet having excellent magnetic properties through step (2) of example 2.
FIG. 2 is a microstructure diagram of a hot-rolled strip obtained by the step (2) of the non-oriented electrical steel sheet having excellent magnetic properties of comparative example 6.
FIG. 3 is a microstructure view of a non-oriented electrical steel sheet having excellent magnetic properties according to example 3.
FIG. 4 is a microstructure view of a non-oriented electrical steel sheet having excellent magnetic properties according to comparative example 5.
FIG. 5 is a microstructure diagram of inclusions in a non-oriented electrical steel sheet having excellent magnetic properties in example 5.
FIG. 6 is a microstructure view of inclusions in a non-oriented electrical steel sheet having excellent magnetic properties according to comparative example 7.
FIG. 7 is a microstructure diagram of inclusions in a non-oriented electrical steel sheet having excellent magnetic properties in example 6.
FIG. 8 is a microstructure view of inclusions in a non-oriented electrical steel sheet having excellent magnetic properties according to comparative example 4.
FIG. 9 is a graph showing the relationship between the length ratio of the major axis to the minor axis of the recrystallized grains in the core of the hot-rolled steel strip obtained in step (2) of the manufacturing method according to the present invention and the core loss of the finally obtained non-oriented electrical steel sheet having excellent magnetic properties.
FIG. 10 is a graph showing the relationship between the length ratio of the major axis to the minor axis of the recrystallized grains of the core portion of the hot-rolled strip obtained in step (2) of the manufacturing method according to the present invention and the magnetic induction of the finally obtained non-oriented electrical steel sheet having excellent magnetic properties.
FIG. 11 is a graph showing the relationship between the average grain size of the recrystallized structure of the core portion of the hot-rolled steel strip obtained in step (2) of the manufacturing method according to the present invention and the core loss of the finally obtained non-oriented electrical steel sheet excellent in magnetic properties.
FIG. 12 is a graph showing the relationship between the average grain size of the recrystallized structure of the core portion of the hot-rolled steel strip obtained in step (2) of the manufacturing method according to the present invention and the magnetic induction of the finally obtained non-oriented electrical steel sheet excellent in magnetic properties.
Detailed Description
The non-oriented electrical steel sheet with excellent magnetic properties and the method for manufacturing the same according to the present invention will be further explained and illustrated with reference to the drawings and the specific examples, which, however, should not be construed to unduly limit the technical scope of the present invention.
Examples 1 to 12 and comparative examples 1 to 7
Tables 1-1 and 1-2 show the mass percentages of the chemical elements in the non-oriented electrical steel sheets having excellent magnetic properties of examples 1-12 and comparative examples 1-7.
TABLE 1-1. (wt.%, balance Fe and unavoidable impurities other than P)
Tables 1-2 (wt%, balance Fe and inevitable impurities other than P)
Note: [ Mn ]]/[Cu]2The medium Mn and Cu both indicate values of these two elements without percentage numbers.
The non-oriented electrical steel sheets having excellent magnetic properties of examples 1 to 12 and comparative examples 1 to 7 were manufactured by the following steps (see table 2 for specific process parameters):
(1) molten iron and scrap steel are subjected to molten iron pretreatment and 150-ton converter smelting according to the mass percentages of chemical elements in tables 1-1 and tables 1-2, and then are refined by a molten steel vacuum circulation degassing method (RH) for decarburization, deoxidation and alloying. The molten steel is continuously cast to prepare a continuous casting billet with the thickness of 170 mm-250 mm and the width of 800 mm-1400 mm. In the continuous casting and solidification process, the cooling rate of the continuous casting billet is controlled to be less than or equal to 10 ℃/min within the temperature range of 1100-1300 ℃, and the cooling rate of the continuous casting billet is controlled to be 20-40 ℃/min within the temperature range of 600-800 ℃.
(2) And hot rolling, wherein the size of a recrystallized structure of the core part of the obtained hot rolled strip is controlled to be 60-75% of the total size of the hot rolled strip in the thickness direction, the average grain size of the recrystallized structure is between 90 and 140 mu m, the major axis of the grains of the recrystallized structure is consistent with the rolling direction of the strip, and the length ratio of the major axis to the minor axis is 1.0-1.6. Wherein the cooling rate of the surface of the strip steel is controlled to be less than or equal to 20 ℃/s in the finish rolling process, water cooling is carried out after the finish rolling is finished to cool the strip steel to the coiling temperature, the time from the finish rolling to the beginning of water cooling is 5-20 s, and the coiling temperature is 750-900 ℃.
(3) Acid washing and continuous rolling.
(4) And (5) continuously annealing.
(5) And (4) coating an insulating coating.
TABLE 2 concrete process parameters of the method for manufacturing non-oriented electrical steel sheets having excellent magnetic properties of examples 1 to 12 and comparative examples 1 to 7
The non-oriented electrical steel sheets of examples 1 to 12 and comparative examples 1 to 7, which are excellent in magnetic properties, were tested for magnetic properties, and the test results are shown in table 3.
Table 3.
| Serial number | Magnetic induction B50(T) | Iron loss P15/50(W/kg) |
| Example 1 | 1.752 | 4.21 |
| Example 2 | 1.749 | 4.09 |
| Example 3 | 1.762 | 4.38 |
| Example 4 | 1.748 | 3.99 |
| Example 5 | 1.761 | 4.18 |
| Example 6 | 1.758 | 4.41 |
| Example 7 | 1.749 | 4.17 |
| Example 8 | 1.755 | 4.32 |
| Example 9 | 1.768 | 4.14 |
| Example 10 | 1.753 | 3.84 |
| Example 11 | 1.753 | 4.12 |
| Example 12 | 1.761 | 4.26 |
| Comparative example 1 | 1.755 | 4.85 |
| Comparative example 2 | 1.731 | 4.83 |
| Comparative example 3 | 1.739 | 5.29 |
| Comparative example 4 | 1.707 | 4.21 |
| Comparative example 5 | 1.725 | 5.14 |
| Comparative example 6 | 1.716 | 5.42 |
| Comparative example 7 | 1.698 | 3.85 |
As can be seen from Table 3, the non-oriented electrical steel sheets of examples 1 to 12 having excellent magnetic properties had an iron loss P15/50Less than or equal to 4.5W/kg, and magnetic induction B50≥1.745T。
In comparative example 1, the content of S element was too low, and the average grain size of the recrystallized structure in the core structure of the strip after hot rolling reached 183 μm and the ratio of the major and minor axes of the grains reached 2.1, so that the non-oriented electrical steel sheet of comparative example 1, which is excellent in magnetic properties, had abnormally high iron loss.
In comparative example 2, the contents of Si and Al elements were too high, [ Mn ]]/[Cu]2Too low, and in addition, the cooling rate of the surface of the strip steel in the finish hot rolling process is as high as 28 ℃/s, the average grain size of the recrystallized structure in the core structure of the strip steel after hot rolling reaches 196 μm, the number of grains of 10 μm or more in the finished strip steel accounts for 93% of the total number of the grains, wherein the number of grains of 10 μm to 30 μm accounts for 75% of the total number of the grains, so that the non-oriented electrical steel sheet of comparative example 2, which is excellent in magnetic properties, has a high iron loss and a low magnetic induction.
In comparative example 3, the content of S element was too high, the internal cooling rate at 600 to 800 ℃ was 18 ℃/min, the proportion of the recrystallized structure size in the core structure of the hot-rolled strip steel in the thickness direction of the hot-rolled strip steel was 78%, and the number of grains of 10 μm or more in the finished strip steel was 58% of the total number of grains, so that the non-oriented electrical steel sheet of comparative example 3, which is excellent in magnetic properties, had a high iron loss abnormality and a low magnetic induction abnormality.
In comparative example 4, the Cu element content was too high, the cooling rate of the continuous cast slab at 1100 to 1300 c was 15.3 c/min, the length ratio of the major axis to the minor axis of the crystal grains in the core structure of the strip after hot rolling was 2.4, and the number of crystal grains of 10 to 30 μm in the finished strip was 48% of the total number of crystal grains, so that the magnetic induction of the non-oriented electrical steel sheet of comparative example 1, which is excellent in magnetic properties, was abnormally high.
In comparative example 5, the content of S element was excessively high, and in addition, the cooling rate of the continuously cast slab at 1100 to 1300 c was excessively high, and further, the ratio of the major axis to the minor axis of the crystal grains in the hot rolled core structure was higher than 1.6, resulting in that the proportion of the crystal grains having a size of 10 μm or more in the finished strip was lower than 65%, resulting in excessively high iron loss of the non-oriented electrical steel sheet of comparative example 5, which is excellent in magnetic properties.
As described above, if 1 technical index does not satisfy the requirements of the composition design and the manufacturing method of the present invention, the electromagnetic properties (e.g., iron loss and magnetic induction) of the obtained non-oriented electrical steel sheet do not satisfy the technical effects of the present invention.
As can be seen from fig. 1 and 2, the grain size of the recrystallized structure of the core of the hot rolled strip obtained by the step (2) of the non-oriented electrical steel sheet excellent in magnetic properties of example 2 accounted for 65% of the total size of the hot rolled strip in the thickness direction, the grains of the recrystallized structure were coarse and uniform, the average grain size was 131um, and the length ratio of the major axis to the minor axis of the grains was 1.4, whereas the core of the hot rolled strip obtained by the step (2) of the non-oriented electrical steel sheet excellent in magnetic properties of comparative example 6 was incomplete in recrystallization, was substantially fibrous in structure, and the grain size of the recrystallized portion of the upper and lower surfaces of the hot rolled strip was fine.
As can be seen from fig. 3 and 4, in the microstructure of the non-oriented electrical steel sheet having excellent magnetic properties of example 3, the number of grains of 10 μm or more was 85% in terms of the total number of grains, wherein the number of grains of 10 μm to 30 μm was 55% in terms of the total number of grains, while in the microstructure of the non-oriented electrical steel sheet having excellent magnetic properties of comparative example 5, the number of grains of 10 μm or more was 61% in terms of the total number of grains, wherein the number of grains of 10 μm to 30 μm was 56% in terms of the total number of grains.
As can be seen from fig. 5 and 6, the inclusions in the non-oriented electrical steel sheet having excellent magnetic properties of example 5 were MnS inclusions having a large size and sufficiently precipitated, and also since the inclusions were easily coarsened and grown under the slow cooling condition, the MnS inclusions maintained a good spherical shape or spheroidal shape. Such spherical or spheroidal inclusions are less likely to form more harmful wedge domains, and thus are easier to magnetize and excellent in magnetic properties. On the other hand, the inclusions in the non-oriented electrical steel sheet of comparative example 7, which had excellent magnetic properties, were MnS and Cu, which were insufficiently precipitated and had a small size2S inclusions are fine in size and numerous in number, and thus are excellent in magnetic properties of the finally obtained magnetic materialThe magnetic properties of good non-oriented electrical steel sheets are very harmful.
As can be seen from FIGS. 7 and 8, since the cooling rate of the ingot in the range of 1100 to 1300 ℃ is 9.4 ℃/min and the cooling rate of the ingot in the range of 600 to 800 ℃ is 28 ℃/min during the manufacturing process, the inclusions in the non-oriented electrical steel sheet having excellent magnetic properties of example 6 are MnS inclusions having large sizes and cluster-like agglomerates, whereas the cooling rate of the ingot in the range of 1100 to 1300 ℃ is 15.3 ℃/min and the cooling rate of the ingot in the range of 600 to 800 ℃ is 45 ℃/min during the manufacturing process of the non-oriented electrical steel sheet having excellent magnetic properties of comparative example 4, the inclusions therein are Cu inclusions having fine sizes and are dispersed2And (4) S inclusions.
As can be seen from fig. 9 and 10, the ratio of the major axis and the minor axis of the crystal grains in the core of the hot rolled steel strip is closely related to the core loss and the magnetic induction of the finally obtained non-oriented electrical steel sheet having excellent magnetic properties, and both are almost monotonous and linear. That is, as the ratio of the major axis to the minor axis of the crystal grains in the core of the hot rolled steel strip increases, the iron loss of the non-oriented electrical steel sheet having excellent magnetic properties increases and the magnetic induction deteriorates. Therefore, the present invention controls the length ratio of the major axis to the minor axis of the crystal grains of the recrystallized structure of the core of the hot-rolled steel strip obtained in the manufacturing method to be 1.0 to 1.6.
As can be seen from fig. 11 and 12, the average grain size of the core of the hot rolled steel strip is closely related to the core loss and the magnetic induction of the finally obtained non-oriented electrical steel sheet having excellent magnetic properties. And the average grain size of the core of the hot rolled strip has a greater influence on the iron loss than on the magnetic induction. Specifically, as the average grain size of the core of the hot rolled steel strip increases, the core loss of a non-oriented electrical steel sheet having excellent magnetic properties rapidly decreases and the magnetic induction rapidly increases. When the average grain size of the core of the hot-rolled strip steel reaches 90um, the iron loss and the magnetic induction of the non-oriented electrical steel plate with excellent magnetic property can respectively reach the iron loss P15/50Less than or equal to 4.5W/kg, and magnetic induction B50≥1.745T。
It should be noted that the prior art in the protection scope of the present invention is not limited to the examples given in the present application, and all the prior art which is not inconsistent with the technical scheme of the present invention, including but not limited to the prior patent documents, the prior publications and the like, can be included in the protection scope of the present invention.
In addition, the combination of the features in the present application is not limited to the combination described in the claims of the present application or the combination described in the embodiments, and all the features described in the present application may be freely combined or combined in any manner unless contradictory to each other.
It should also be noted that the above-mentioned embodiments are only specific embodiments of the present invention. It is apparent that the present invention is not limited to the above embodiments and similar changes or modifications can be easily made by those skilled in the art from the disclosure of the present invention and shall fall within the scope of the present invention.
Claims (9)
1. A non-oriented electrical steel sheet with excellent magnetic property is characterized in that the non-oriented electrical steel sheet comprises the following chemical elements by mass percent:
c is more than 0 and less than or equal to 0.005 percent, Si: 0.1-1.2%, Mn: 0.1-1.0%, S: 0.008-0.020%, Al: 0.1 to 0.4%, Cu: 0.01-0.05%, N more than 0 and less than or equal to 0.003%, Ti and less than or equal to 0.002%, and the balance of Fe and other inevitable impurities;
the non-oriented electrical steel sheet has a grain size of 10 μm or more accounting for 65 to 85% of the total grain size, and a grain size of 10 to 30 μm accounting for 50 to 70% of the total grain size.
2. A non-oriented electrical steel sheet excellent in magnetic characteristics as claimed in claim 1, which has inclusions mainly of spherical or spheroidal MnS.
3. The non-oriented electrical steel sheet having excellent magnetic properties as claimed in claim 2, which further has a very small amount of Cu2S inclusions, very small amount of Cu2The S inclusions are precipitated with the MnS inclusions as a core and are aggregated around the MnS inclusions.
4. The non-oriented electrical steel sheet having excellent magnetic properties as claimed in claim 1, wherein the Mn and Cu elements satisfy: [ Mn ]]/[Cu]2300-1500, wherein Mn and Cu both represent the values of the two elements without percentage numbers.
5. The non-oriented electrical steel sheet having excellent magnetic properties as claimed in claim 1, wherein the core loss P is15/50Less than or equal to 4.5W/kg, and magnetic induction B50≥1.745T。
6. The method of manufacturing a non-oriented electrical steel sheet having excellent magnetic properties as claimed in any one of claims 1 to 5, comprising the steps of:
(1) preparing a continuous casting billet;
(2) hot rolling;
(3) acid washing and continuous rolling;
(4) continuous annealing;
(5) and (4) coating an insulating coating.
7. The manufacturing method according to claim 6, wherein in the step (1), the cooling rate of the continuously cast slab is controlled to be 10 ℃/min or less at a temperature range of 1100 ℃ to 1300 ℃ and to be 20 ℃/min to 40 ℃/min at a temperature range of 600 ℃ to 800 ℃ during the continuous casting and solidification.
8. The manufacturing method according to claim 6 or 7, wherein in the step (2), the size of the recrystallized structure of the core portion of the obtained hot-rolled steel strip accounts for 60% to 75% of the total size of the hot-rolled steel strip in the thickness direction; wherein the average grain size of the recrystallized structure is between 90 and 140 mu m; the long axis of the crystal grains of the recrystallized structure is consistent with the rolling direction of the strip steel, and the length ratio of the long axis to the short axis is 1.0-1.6.
9. The production method according to claim 6 or 7, wherein in the step (2), the cooling rate of the surface of the strip is controlled to be 20 ℃/s or less during the finish rolling, and water cooling is performed after the finish rolling to cool the strip to a coiling temperature, wherein the time from the finish rolling to the start of the water cooling is 5 to 20 seconds, and the coiling temperature is 750 to 900 ℃.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DD156651A1 (en) * | 1981-02-25 | 1982-09-08 | Peter Klemm | ELECTROBLECH WITH INCREASED INDUCTIONS FOR MEDIUM FIELD STONES |
| JPH0463228A (en) * | 1990-07-02 | 1992-02-28 | Nippon Steel Corp | Manufacture of nonoriented silicon steel sheet excellent in magnetic property before and after magnetic annealing |
| CN1380908A (en) * | 2000-06-19 | 2002-11-20 | 日本钢管株式会社 | Non-oriented electromagnetic steel sheet and method for producing therefor |
| CN101463448A (en) * | 2007-12-18 | 2009-06-24 | 鞍钢股份有限公司 | High magnetic strength non-oriented electrical steel and production method thereof |
| CN102758150A (en) * | 2011-04-28 | 2012-10-31 | 宝山钢铁股份有限公司 | High-yield-strength non-oriented electrical steel plate and manufacturing method thereof |
| CN103388106A (en) * | 2013-06-27 | 2013-11-13 | 宝山钢铁股份有限公司 | Non-oriented electrical steel plate with high magnetic induction and low iron loss, and manufacturing method thereof |
| CN103526001A (en) * | 2013-09-24 | 2014-01-22 | 马钢(集团)控股有限公司 | Manufacturing method of cold-rolled non-oriented electrical steel for constant-frequency compressors |
| JP2016125134A (en) * | 2015-01-08 | 2016-07-11 | Ｊｆｅスチール株式会社 | Non-oriented silicon steel sheet excellent in recyclability and method for producing the same |
| CN106574345A (en) * | 2014-08-21 | 2017-04-19 | 杰富意钢铁株式会社 | Non-oriented electrical steel sheet and manufacturing method thereof |
| CN107794439A (en) * | 2016-08-30 | 2018-03-13 | 宝山钢铁股份有限公司 | Extra-low iron loss non-oriented electromagnetic steel sheet and its manufacture method |
-
2018
- 2018-06-26 CN CN201810671399.4A patent/CN110643891B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DD156651A1 (en) * | 1981-02-25 | 1982-09-08 | Peter Klemm | ELECTROBLECH WITH INCREASED INDUCTIONS FOR MEDIUM FIELD STONES |
| JPH0463228A (en) * | 1990-07-02 | 1992-02-28 | Nippon Steel Corp | Manufacture of nonoriented silicon steel sheet excellent in magnetic property before and after magnetic annealing |
| CN1380908A (en) * | 2000-06-19 | 2002-11-20 | 日本钢管株式会社 | Non-oriented electromagnetic steel sheet and method for producing therefor |
| CN101463448A (en) * | 2007-12-18 | 2009-06-24 | 鞍钢股份有限公司 | High magnetic strength non-oriented electrical steel and production method thereof |
| CN102758150A (en) * | 2011-04-28 | 2012-10-31 | 宝山钢铁股份有限公司 | High-yield-strength non-oriented electrical steel plate and manufacturing method thereof |
| CN103388106A (en) * | 2013-06-27 | 2013-11-13 | 宝山钢铁股份有限公司 | Non-oriented electrical steel plate with high magnetic induction and low iron loss, and manufacturing method thereof |
| CN103526001A (en) * | 2013-09-24 | 2014-01-22 | 马钢(集团)控股有限公司 | Manufacturing method of cold-rolled non-oriented electrical steel for constant-frequency compressors |
| CN106574345A (en) * | 2014-08-21 | 2017-04-19 | 杰富意钢铁株式会社 | Non-oriented electrical steel sheet and manufacturing method thereof |
| JP2016125134A (en) * | 2015-01-08 | 2016-07-11 | Ｊｆｅスチール株式会社 | Non-oriented silicon steel sheet excellent in recyclability and method for producing the same |
| CN107794439A (en) * | 2016-08-30 | 2018-03-13 | 宝山钢铁股份有限公司 | Extra-low iron loss non-oriented electromagnetic steel sheet and its manufacture method |
Non-Patent Citations (3)
| Title |
|---|
| Cu元素对无取向电工钢板表层织构的影响;黄希等;《金属热处理》;20130331;第38卷(第3期);31-35 * |
| Effect of copper precipitates on the stability of microstructures and magnetic properties of non-oriented electrical steels;Meng Wu, Yanping Zeng;《Journal of Magnetism and Magnetic Materials》;20150423;第391卷;96-100 * |
| 在线观察不同冷却速率下无取向硅钢中的夹杂物的析出;张峰等;《电工材料》;20180620(第3期);第17-22页 * |
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