High-strength fe-si soft magnetic material and manufacturing method therefor

Abstract

Disclosed in the present invention is a high-strength Fe-Si soft magnetic material, comprising Fe and inevitable impurities, and further comprising the following chemical elements in wt%: 2.85-3.30% of Si, 0.20-1.25% of Mn, 0.80-1.40% of Al, 0.005-2.000% of Cu, 0.0003-0.0100% of B, and 0.0005-0.0050% of C. Further disclosed in the present invention is a method for manufacturing the high-strength Fe-Si soft magnetic material, comprising the following steps: smelting and casting; hot rolling; annealing of a hot-rolled sheet; cold rolling; annealing of a finished product: in the heating zone, the temperature is 645°C-715°C, and the heating rate is controlled in the range of 60°C / s-175°C / s, and in the soaking zone, the temperature is 720°C-820°C, and the thermal preservation duration is 20 s-120 s; and coating an insulating coating.

Description

A high-strength Fe-Si soft magnetic material and its manufacturing method Technical Field

[0001] This invention relates to a metallic material, and more particularly to an Fe-Si soft magnetic material. Background Technology

[0002] With the development of the new energy vehicle industry, the demand for drive motors, one of the core components of the power system, is increasing, and the performance requirements are becoming more stringent, imposing stringent requirements on the efficiency, weight, size, and safety of drive motors. Taking a typical permanent magnet synchronous drive motor as an example, high power density, high reliability, and miniaturization are the main development directions of electric drive systems, and high speed is one of the important means to improve power density. Under the same power conditions, as the rotor speed increases, the torque decreases accordingly, and the motor size will decrease accordingly, resulting in less material usage and weight reduction.

[0003] For Fe-Si soft magnetic alloys that make up motors, when used as rotors, they need to have sufficiently high strength, and when used as stators, they need to have high frequency and low loss, so as to meet the risk of fracture failure under high speed conditions required by high power density drive motors, while reducing energy loss.

[0004] Chinese patent document CN108044100A, published on May 18, 2018, entitled "A Method for Preparing Fe-6.5%Si Soft Magnetic Material Thin Strips by Powder Rolling," discloses a method for preparing Fe-6.5%Si soft magnetic material thin strips by powder rolling. The method involves mixing water-atomized iron powder and high-purity ferrosilicon powder to obtain a mixed powder of Fe-4.5% to 6.7%Si. This powder is then subjected to powder rolling, degreasing and sintering, multiple cold rolling cycles, and multiple intermediate densification sintering cycles to obtain 0.1-0.5 mm thick sheets. Preferably, further homogenization high-temperature sintering at 1265-1335℃ is required for 1-4 hours, ultimately yielding a density of 7.34-7.49 g / cm³. 3 The Fe-6.5%Si alloy strip is described. However, the preparation process in the aforementioned patent documents is cumbersome and complex, making it unsuitable for large-scale production. Furthermore, the high-frequency iron loss level and mechanical properties of this soft magnetic material are not disclosed. Summary of the Invention

[0005] One of the objectives of this invention is to provide a high-strength Fe-Si soft magnetic material. Through the design of the material composition, microstructure and special grain boundary control, this material has the properties of high strength, high frequency and low loss, which can meet the requirements of high efficiency, miniaturization and high reliability of high power density drive motors.

[0006] To achieve the above objectives, this invention proposes an Fe-Si soft magnetic material containing Fe and unavoidable impurities, and further containing the following chemical elements in wt% terms:

[0007] Si: 2.85-3.30%, Mn: 0.20-1.25%, preferably Mn: 0.60-1.25%, Al: 0.80-1.40%, Cu: 0.005-2.000%, preferably Cu: 0.500-2.000%, B: 0.0003-0.0100%, preferably B: 0.0010-0.0100%, C: 0.0005-0.0050%.

[0008] Preferably, the Fe-Si soft magnetic material of the present invention contains the following chemical elements in wt% terms:

[0009] Si: 2.85-3.30%, Mn: 0.20-1.25%, preferably Mn: 0.60-1.25%, Al: 0.80-1.40%, Cu: 0.005-2.000%, preferably Cu: 0.500-2.000%, B: 0.0003-0.0100%, preferably B: 0.0010-0.0100%, C: 0.0005-0.0050%; balance Fe and unavoidable impurities.

[0010] The design principles of each chemical element in the Fe-Si soft magnetic material described in this invention are as follows:

[0011] Si: In the Fe-Si soft magnetic material described in this invention, Si is an element that increases the resistivity of the alloy. Si can reduce iron loss and also plays a role in solid solution strengthening. To achieve the effects of this invention, the Si content is controlled to be above 2.85%. However, when the mass percentage of Si is too high, it will reduce the processability of the material and increase the risk of strip breakage during cold rolling. Therefore, in the Fe-Si soft magnetic material described in this invention, the mass percentage of Si is controlled in the range of 2.85-3.30%, preferably in the range of 2.90-3.30%.

[0012] Mn: In the Fe-Si soft magnetic material of this invention, adding a certain amount of Mn can improve hot rolling plasticity, increase material resistivity, and reduce losses. However, when the mass percentage of Mn is too high, it will increase the alloy cost, and the performance improvement will be limited. Therefore, in the Fe-Si soft magnetic material of this invention, the mass percentage of Mn is controlled within the range of 0.20-1.25%, preferably within the range of 0.60-1.25%, and more preferably within the range of 0.65-1.25%.

[0013] Al: In the Fe-Si soft magnetic material described in this invention, the effect of Al on improving the magnetic properties of the soft magnetic material is similar to that of Si. It can increase the resistivity of the soft magnetic alloy, reduce losses, and at the same time promote grain growth during heat treatment. In order to achieve the goal of further grain growth through stress-relief annealing as described in this invention, the Al content is above 0.80%. However, when the mass percentage of Al is too high, it will increase the difficulty of cold rolling the hot-rolled plate, and the reduction in iron loss will be limited. Therefore, in the Fe-Si soft magnetic material described in this invention, the mass percentage of Al is controlled in the range of 0.80-1.40%, preferably in the range of 0.80-1.30%.

[0014] Cu: In the Fe-Si soft magnetic material of this invention, the addition of an appropriate amount of Cu element can be controlled during the final annealing process to form a nanoscale copper-rich phase precipitation. This can improve the strength of the material without affecting the magnetic domain movement during the magnetization process, and without deteriorating iron loss. To achieve the desired effect, the addition amount is controlled to be above 0.005%, and considering cost, its upper limit should not exceed 2.000%. Therefore, in the Fe-Si soft magnetic material of this invention, the mass percentage content of Cu element is controlled in the range of 0.005-2.000%, preferably in the range of 0.500-2.000%.

[0015] B: In the Fe-Si soft magnetic material described in this invention, boron (B) readily accumulates at grain boundaries. The addition of an appropriate amount of boron can strengthen grain boundaries and improve cold rolling performance; therefore, the addition amount is controlled to be above 0.0003%. However, when the mass percentage of boron is too high, it is detrimental to grain growth during subsequent stress-relief annealing and instead worsens iron loss. Therefore, in the Fe-Si soft magnetic material described in this invention, the mass percentage of boron is controlled within the range of 0.0003-0.0100%, preferably within the range of 0.0010-0.0100%.

[0016] C: In the Fe-Si soft magnetic material described in this invention, C is a magnetically detrimental element. When its content is too high, the material will undergo magnetic aging, and excessive carbon will precipitate in the form of carbides, causing an increase in iron loss. Generally, it is controlled below 0.0050%, preferably below 0.0030%. However, if the carbon content is too low, it will increase the decarburization time in the smelting process, reduce production efficiency, and increase costs. Therefore, it is controlled above 0.0005%. Thus, in the Fe-Si soft magnetic material described in this invention, the mass percentage content of C is controlled within the range of 0.0005-0.0050%. In some embodiments, the mass percentage content of C can be controlled within the range of 0.0005-0.0050%.

[0017] Preferably, the Fe-Si soft magnetic material of the present invention further comprises at least one of the following:

[0018] Sn: 0.01000.3000%;

[0019] 0 < Ca + REM ≤ 0.0100%.

[0020] In the above technical solution of the present invention, in order to further optimize the performance of the non-oriented electrical steel described in the present invention, the steel may also contain Sn, REM rare earth elements, and Ca. Wherein:

[0021] Sn: In the Fe-Si soft magnetic material described in this invention, Sn is a grain boundary segregation element. Sn segregation at grain boundaries can prevent internal oxidation during the strip annealing process, while simultaneously improving the material texture and enhancing the magnetic properties of the Fe-Si soft magnetic material. However, when the mass percentage of Sn is too high, it will refine the grain structure and increase the alloy cost. Therefore, in the Fe-Si soft magnetic material described in this invention, the mass percentage of Sn is controlled within the range of 0.0100-0.3000%, preferably within the range of 0.0600-0.3000%.

[0022] Ca+REM: In the Fe-Si soft magnetic material described in this invention, both REM rare earth elements and Ca can improve the morphology of inclusions in the soft magnetic material. By purifying the quality of the molten liquid during the alloy smelting process, they promote the growth of oxide inclusions, which can also promote the stress-relief annealing process and further increase the grain size, thereby reducing the iron loss P after stress-relief annealing. 10 / 800(S) However, when the mass percentages of REM rare earth elements and Ca are too high, it can lead to surface defects in the alloy strip. Therefore, in the Fe-Si soft magnetic material of this invention, the mass percentages of REM rare earth elements and Ca are controlled to 0 < Ca + REM ≤ 0.0100%, preferably 0.0008 ≤ Ca + REM ≤ 0.0100%.

[0023] Optionally, 0 < Ca ≤ 0.0060% (preferably 0.0008 ≤ Ca ≤ 0.0060%), and / or 0 < REM ≤ 0.0100% (preferably 0.0010 ≤ REM ≤ 0.0100%).

[0024] Preferably, the unavoidable impurities in the Fe-Si soft magnetic material of the present invention include P and S, wherein P ≤ 0.025% and S ≤ 0.0025%.

[0025] In the non-oriented electrical steel described in this invention, both phosphorus (P) and sulfur (S) are impurity elements in the non-oriented electrical steel sheet. Where technical conditions permit, to obtain steel with better performance and superior quality, the content of impurity elements in the steel should be reduced as much as possible. Wherein:

[0026] P: In the Fe-Si soft magnetic material described in this invention, for soft magnetic alloy materials with a Si content exceeding 2.85%, phosphorus (P) can be controlled as an impurity element. P readily segregates at grain boundaries, leading to embrittlement of the steel plate and difficulties in cold rolling. Therefore, in the Fe-Si soft magnetic material described in this invention, the mass percentage of P is controlled to P ≤ 0.025%, preferably P ≤ 0.021%.

[0027] S: In the Fe-Si soft magnetic material of this invention, sulfur (S) is an impurity element. It combines with manganese (Mn) to form fine MnS precipitates, hindering grain growth and degrading magnetic properties. Therefore, its content must be below 0.0025%. Thus, in the Fe-Si soft magnetic material of this invention, the mass percentage of sulfur is controlled to S ≤ 0.0025%, preferably S ≤ 0.0024%.

[0028] Preferably, in the Fe-Si soft magnetic material of the present invention, its {100} <490> The ratio of the contents of Σ5 and Σ13 at the overlapping lattice grain boundaries around the oriented grains satisfies the following relationship: 0.80 ≤ Σ5 / Σ13 ≤ 1.00. Preferably, 0.85 ≤ Σ5 / Σ13 ≤ 1.00.

[0029] It should be noted that Σ is the reciprocal of the "coincidence position lattice density". "Σ5 grain boundary" refers to a special grain boundary where adjacent grains share Σ5 coincidence position lattice characteristics along the lattice plane of the coincidence lattice. "Σ13 grain boundary" refers to a special grain boundary where adjacent grains share Σ13 coincidence position lattice characteristics. In this invention, the content of Σ5 is calculated by dividing the length of the Σ5 grain boundary by the total grain boundary length, and similarly, the content of Σ13 is calculated by dividing the length of the Σ13 grain boundary by the total grain boundary length.

[0030] In this invention, after annealing, the Fe-Si soft magnetic material has a microcrystalline structure containing {100}. <490> The texture has its {100} crystal plane parallel to the strip surface. During the magnetization process in rotating electrical machinery, its {100} crystal plane contains two easily magnetized... <100> The shaft helps reduce magnetic losses in materials, and {100} <490> The area surrounding the oriented grain (i.e., the grain boundary interface formed between the oriented grain and other adjacent grains) contains coincident lattice grain boundaries Σ5 and Σ13, with the ratio of their contents satisfying the relationship: 0.80≦Σ5 / Σ13≦1.00. This grain boundary structure allows {100} <490> The grain boundary energy between oriented grains and other oriented grains is in a low state. This low-energy grain boundary is beneficial on the one hand to the movement of magnetic domain walls during the magnetization process, and on the other hand to the continued growth of grains during stress-relief annealing. <490> Oriented grains preferentially move and grow at the interface.

[0031] Preferably, in the Fe-Si soft magnetic material product of the present invention, the iron loss P10 / 800(A) ≤64.0W / kg, preferred P 10 / 800(A) ≤62.2W / kg, yield strength ≥465MPa, preferably 465MPa≤yield strength≤515MPa.

[0032] In this invention, the Fe-Si soft magnetic material can be directly used as the core rotor of a drive motor. After lamination, the material does not require stress-relief annealing. The high-frequency iron loss P at 800Hz and a maximum magnetic polarization of 1.0T is [not specified]. 10 / 800(A) With a strength of ≤64.0W / kg and a yield strength of ≥465MPa, the rotor can operate at high speed without breaking, while keeping motor losses at a low level.

[0033] Preferably, the thickness of the Fe-Si soft magnetic material of the present invention is ≤0.30mm, more preferably 0.25-0.30mm.

[0034] Preferably, the iron loss P of the Fe-Si soft magnetic material of the present invention after stress-relief annealing is... 10 / 800(S) Iron loss P before stress relief annealing 10 / 800(A) Satisfying the relation: P 10 / 800(S) / P 10 / 800(A) ≤0.900, preferred P 10 / 800(S) / P 10 / 800(A) ≤0.889.

[0035] In this invention, P 10 / 800(A) P represents the specific total loss per kilogram of sample before stress-relief annealing at a frequency of 800 Hz and a maximum magnetic polarization of 1.0 T; 10 / 800(S) This represents the total loss per kilogram of sample after stress-relief annealing at a frequency of 800 Hz and a maximum magnetic polarization of 1.0 T.

[0036] Since the iron loss of an electric motor mainly consists of stator and rotor iron losses, with the stator side material causing the majority of the iron loss, when the Fe-Si alloy soft magnetic material of this invention is used as the stator core of a drive motor, the stator core is in a relatively static state during motor operation. Therefore, the strength requirements for the material are not as high as those for the rotor. Thus, further stress-relief annealing can be performed, which reduces the material strength to some extent, but further reduces the iron loss. This invention contains {100} <490> Texture, and {100} <490> The ratio of Σ5 and Σ13 contents at the coincident lattice grain boundaries around the oriented grains satisfies the relationship: 0.80≤Σ5 / Σ13≤1.00. After stress-relief annealing, the high-frequency iron loss P 10 / 800(S) The iron loss is significantly reduced, with a value of no more than 0.900 compared to the iron loss before stress-relief annealing, which well meets the design requirements of motors such as electric vehicle drive motors.

[0037] Another object of the present invention is to provide a method for manufacturing Fe-Si soft magnetic material, which can obtain a Fe-Si soft magnetic material with high frequency and low loss properties.

[0038] To achieve the above objectives, this invention proposes a method for manufacturing Fe-Si soft magnetic materials, the method comprising the following steps:

[0039] (1) Smelting and casting;

[0040] (2) Hot rolling;

[0041] (3) Annealing of hot-rolled sheet;

[0042] (4) Cold rolling;

[0043] (5) Finished product annealing: In the heating and heating section, the heating rate is controlled in the range of 60℃ / s-175℃ / s, the temperature of the heat soaking section is 720℃-820℃, and the heat soaking section holding time is 20s-120s.

[0044] (6) Apply an insulating coating.

[0045] Preferably, step (1) includes: blast furnace molten iron undergoes molten iron pretreatment, converter smelting, RH refining, and continuous casting and rolling to obtain a billet.

[0046] Preferably, in step (2), the billet heating temperature does not exceed 1200℃, the final rolling temperature does not exceed 900℃, and the hot-rolled plate thickness is ≤2.0mm.

[0047] Preferably, in step (3), the heat preservation temperature does not exceed 950°C.

[0048] In step (5), the heating rate within the 645℃-715℃ range is controlled within the range of 60℃ / s-175℃ / s because: when the heating temperature exceeds 645℃, recrystallization and nucleation begin inside the alloy strip. By controlling the heating rate in this range to be above 60℃ / s, it is beneficial to {100} <490> Nucleation of oriented grains. However, when the heating rate exceeds 175℃ / s, the residence time in the recrystallization nucleation range of 645℃-715℃ is too short, which is actually detrimental to {100}. <490> Oriented grain nucleation.

[0049] In step (5), the temperature T of the soaking zone is controlled to satisfy: 720℃≤T≤820℃, and the residence time in the soaking zone is 20s-120s, which allows the recrystallized grains to grow. <490> Special overlapping lattice grain boundary structures, Σ5 and Σ13, are formed around the oriented grains, resulting in a ratio of Σ5 / Σ13 content between 0.80 and 1.00. Excessively high homogenization temperature or prolonged homogenization time can lead to excessively large grains, reduced yield strength, and a Σ5 / Σ13 ratio less than 0.80, which is detrimental to stress-relief annealing. <490> The oriented grains grow further. Therefore, the upper limit of the soaking temperature is controlled to not exceed 820℃, and the upper limit of the soaking time is controlled to not exceed 120s.

[0050] Preferably, the manufacturing method of the present invention further includes a stress-relief annealing step after step (6).

[0051] Preferably, the iron loss P of the finished product after stress-relief annealing 10 / 800(S) Iron loss P before stress relief annealing 10 / 800(A) Satisfying the relation: P 10 / 800(S) / P 10 / 800(A) ≤0.900.

[0052] Preferably, in the stress-relief annealing step: the annealing temperature is 740℃-850℃, and the holding time is 60-180min.

[0053] In this invention, to meet the requirement of lower iron loss in the motor core stator, the finished annealed strip can undergo stress-relief annealing. Holding time exceeding 60 minutes allows for sufficient grain growth, reducing material iron loss. However, excessively long soaking times result in low production efficiency and increased manufacturing costs. Therefore, in this invention, the holding time is controlled between 60 and 180 minutes.

[0054] The Fe-Si soft magnetic material and its manufacturing method described in this invention have the following advantages and beneficial effects:

[0055] The Fe-Si soft magnetic material described in this invention, through the design of material composition, microstructure and special grain boundary control, has high-frequency and low-loss performance, which can meet the requirements of high efficiency, miniaturization and high reliability of high power density drive motors.

[0056] In some embodiments, the Fe-Si soft magnetic material exhibits a low iron loss P in the finished product without stress-relief annealing. 10 / 800(A) ≤64.0W / kg, preferred P 10 / 800(A) ≤62.2W / kg, yield strength ≥465MPa, preferably 465MPa≤yield strength≤515MPa.

[0057] In some embodiments, the Fe-Si soft magnetic material undergoes stress-relief annealing followed by iron loss P. 10 / 800(S) Iron loss P before stress relief annealing 10 / 800(A) Satisfying the relation: P 10 / 800(S) / P 10 / 800(A) ≤0.900. Detailed Implementation

[0058] The Fe-Si soft magnetic material and its manufacturing method described in this invention will be further explained and described below with reference to specific embodiments. However, such explanation and description do not constitute an undue limitation on the technical solution of this invention.

[0059] Examples 1-8 and Comparative Examples 1-5

[0060] The Fe-Si soft magnetic materials of Examples 1-8 and the comparative materials of Comparative Examples 1-5 of the present invention were prepared using the following steps:

[0061] (1) Smelting and casting: blast furnace molten iron undergoes molten iron pretreatment, converter smelting, RH refining, and continuous casting and rolling to obtain cast billets.

[0062] (2) Hot rolling: The billet is heated to 1200℃, held for 1 hour, and then rolled to 900℃ to a final thickness of 2.0mm.

[0063] (3) Hot-rolled plate annealing: In order to fully recrystallize the grain structure of the hot-rolled plate, the holding temperature is 950℃ and the holding time is 15min.

[0064] (4) Cold rolling: Cold rolling yields a finished product with a thickness of 0.25 or 0.30 mm.

[0065] (5) Finished product annealing: In the heating and heating section, the heating rate is controlled in the range of 60℃ / s-175℃ / s within the range of 645℃-715℃. The temperature of the heat soaking section is 720℃-820℃, and the heat soaking section holding time is 20s-120s.

[0066] (6) Applying an insulating coating: After the finished product is annealed, an insulating coating is applied to the surface of the material.

[0067] In some implementations, stress-relief annealing is performed after the step of applying the insulating coating.

[0068] In some more specific embodiments, the finished material is cut into Epstein square magnetic test specimens and then subjected to stress-relief annealing: the stress-relief annealing temperature is 740℃-850℃ and the holding time is 60-180min.

[0069] Tables 1-1 and 1-2 list the mass percentage of each chemical element in the finished Fe-Si soft magnetic materials of Examples 1-8 and the comparative materials of Comparative Examples 1-5.

[0070] Table 1-1. (wt%, balance Fe and unavoidable impurities other than P and S)

[0071] Table 1-2. (wt%, balance Fe and unavoidable impurities other than P and S)

[0072] Table 2 lists the specific process parameters for the Fe-Si soft magnetic materials of Examples 1-8 and the comparative materials of Comparative Examples 1-5 in the "finished product annealing" and optional "stress-relief annealing" steps.

[0073] Table 2.

[0074] Samples were taken from the Fe-Si soft magnetic materials of Examples 1-8 and the comparative materials of Comparative Examples 1-5 before and after stress-relief annealing, and the iron loss P before stress-relief annealing was measured. 10 / 800(A) Iron loss P after stress-relief annealing 10 / 800(S) Yield strength and its {100} <490> The ratio of Σ5 to Σ13 content at overlapping lattice grain boundaries around the oriented grains was measured, and the results are listed in Table 3. The specific detection method is described below:

[0075] Iron loss P 10 / 800 Test: Based on the square circle method of the standard "GB / T10129-2019 Measurement Method of Medium Frequency Magnetic Properties of Electrical Steel Strips (Sheets)".

[0076] Yield strength performance index test: based on the standard GB / T 228.1-2010 Metallic materials, tensile testing - Part 1: Test method at room temperature.

[0077] Statistical analysis of overlapping lattice grain boundaries Σ5 and Σ13: Electron backscatter diffraction (EBSD) was used for testing, referring to the standard GB / T 19501-2013 "General Rules for Microbeam Analysis Electron Backscatter Diffraction Analysis". 15*20mm samples were randomly cut from finished annealed strips, with the observation surface being an RD*ND cross section. The samples were ground, mechanically polished, and electrolytically polished, then observed under a field emission scanning electron microscope equipped with an EBSD testing system. The test conditions were set to a reference voltage of 20kV, a current of 30μA, and a scanning step of 1μm. Four fields of view were randomly selected for each sample, with a total statistical area of ​​no less than 1,000,000μm. 2 Then, the overlapping lattice grain boundaries, total length, and relative proportion are calculated using the device's EBSD data analysis software.

[0078] Table 3 lists the performance test results of the Fe-Si soft magnetic materials of Examples 1-8 and the comparative materials of Comparative Examples 1-5.

[0079] Table 3.

[0080] As can be seen from Table 3 above, in Examples 1-8 of the present invention, the key parameters of alloy chemical composition control during the smelting process, heating rate in a specific range during the finished product annealing process, holding temperature and time are all within the design range of the present invention, thus obtaining the iron loss P of the finished Fe-Si alloy strip before stress-relief annealing. 10 / 800(A) All values ​​are less than 64.0 W / kg, and the yield strength is greater than or equal to 465 MPa, meeting the requirement that the rotor core does not fracture during high-speed rotation.

[0081] Furthermore, in the microstructure of the finished product before stress-relief annealing, {100} <490> The ratio of Σ5 and Σ13 content at the overlapping lattice grain boundaries around the oriented grains is between 0.80 and 1.00. After stress-relief annealing, the high-frequency iron loss is further significantly reduced, with a loss ratio of less than 0.900 compared to that before stress-relief annealing. When used as a stator material for motors, it can meet the requirements for high-frequency low loss in stators.

[0082] In contrast, although the manufacturing process and finished product annealing process of Comparative Examples 1 and 2 are within the scope of this invention, their chemical composition is not within the scope of this invention. Therefore, the high-frequency iron loss and yield strength of the finished products are not within the scope of this invention.

[0083] Furthermore, in Comparative Example 3, the heating rate during the annealing process of the finished product in the 645℃-715℃ range was outside the scope of this invention, resulting in {100} <490> The ratio of Σ5 to Σ13 of the overlapping lattice grain boundaries around the oriented grains exceeds 0.80-1.00, resulting in limited reduction of high-frequency iron loss after stress-relief annealing.

[0084] The heating rate of Comparative Example 4 exceeded 175℃ / s, resulting in an excessively short residence time in the recrystallization nucleation region, which is unfavorable for {100}. <490> Oriented grain nucleation results in high iron loss in the finished product, and the reduction in iron loss is limited even after stress-relief annealing.

[0085] Although Comparative Example 5 has chemical composition and heating rate within the scope of the invention, its homogenization temperature and holding time are outside the scope of the invention, resulting in {100} <490> When the ratio of Σ5 to Σ13 of the overlapping lattice grain boundaries around the oriented grains exceeds 0.80-1.00, the yield strength of the finished material is relatively low.

[0086] It should be noted that the scope of protection of the prior art in this invention is not limited to the embodiments given in this application. All prior art that does not contradict the solution of this invention, including but not limited to prior patent documents, prior publications, prior public uses, etc., can be included in the scope of protection of this invention.

[0087] Furthermore, the combination of the technical features in this case is not limited to the combination methods described in the claims of this case or the combination methods described in the specific embodiments. All technical features described in this case can be freely combined or combined in any way, unless they contradict each other.

[0088] It should also be noted that the embodiments listed above are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made thereto are those that can be directly derived or easily conceived by those skilled in the art from the content disclosed in the present invention, and should all fall within the protection scope of the present invention.

Claims

1. A Fe-Si soft magnetic material, which, in addition to Fe and unavoidable impurities, contains the following chemical elements in wt% quantities: Si: 2.85-3.30%, Mn: 0.20-1.25%, preferably Mn: 0.60-1.25%, Al: 0.80-1.40%, Cu: 0.005-2.000%, preferably Cu: 0.500-2.000%, B: 0.0003-0.0100%, preferably B: 0.0010-0.0100%, C: 0.0005-0.0050%.

2. The Fe-Si soft magnetic material of claim 1, wherein The Fe-Si soft magnetic material contains the following chemical elements in wt% terms: Si: 2.85-3.30%, Mn: 0.20-1.25%, preferably Mn: 0.60-1.25%, Al: 0.80-1.40%, Cu: 0.005-2.000%, preferably Cu: 0.500-2.000%, B: 0.0003-0.0100%, preferably B: 0.0010-0.0100%, C: 0.0005-0.0050%; balance Fe and unavoidable impurities.

3. The Fe-Si soft magnetic material according to claim 1 or 2, characterized in that The Fe-Si soft magnetic material also contains at least one of the following: Sn: 0.0100-0.3000%; 0 < Ca + REM ≤ 0.0100%.

4. The Fe-Si soft magnetic material according to claim 1 or 2, characterized in that Unavoidable impurities include P and S, where P ≤ 0.025% and S ≤ 0.0025%.

5. The Fe-Si soft magnetic material according to claim 1 or 2, characterized in that The Fe-Si soft magnetic material {100} <490> The ratio of the contents of Σ5 and Σ13 at the overlapping lattice grain boundaries around the oriented grains satisfies the following relationship: 0.80≤Σ5 / Σ13≤1.00, preferably 0.85≤Σ5 / Σ13≤1.

00.

6. The Fe-Si soft magnetic material according to claim 1 or 2, characterized in that The Fe-Si soft magnetic material has a core loss P 10 / 800(A) ≤ 64.0 W / kg, preferably ≤ 62.2 W / kg, a yield strength ≥ 465 MPa, preferably 465-515 MPa.

7. The Fe-Si soft magnetic material according to claim 1 or 2, characterized in that The Fe-Si soft magnetic material has a core loss P 10 / 800(S) and a core loss P before stress relief annealing 10 / 800(A) satisfying the relationship: P 10 / 800(S) / P 10 / 800(A) ≤ 0.900; and / or the thickness of the Fe-Si soft magnetic material is ≤ 0.30 mm, preferably 0.25-0.30 mm.

8. A method of manufacturing the Fe-Si soft magnetic material according to any one of claims 1 to 7, characterized by, The method includes the following steps: (1) Smelting and casting; (2) Hot rolling; (3) Annealing of hot-rolled sheet; (4) Cold rolling; (5) Finished product annealing: In the heating and heating section, the heating rate is controlled in the range of 60℃ / s-175℃ / s, the temperature of the heat soaking section is 720℃-820℃, and the heat soaking section holding time is 20s-120s. (6) Apply an insulating coating.

9. The method of claim 8, wherein, The method further comprises a stress relief annealing step after step (6); preferably, the iron loss P 10 / 800(S) and the iron loss P 10 / 800(A) satisfies the relationship: P 10 / 800(S) / P 10 / 800(A) ≤ 0.

900.

10. The method of claim 9, wherein, In the stress-relief annealing step: the annealing temperature is 740℃-850℃, and the holding time is 60-180min.

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