WO2024002260A1

WO2024002260A1 - Oriented silicon steel and manufacturing method therefor

Info

Publication number: WO2024002260A1
Application number: PCT/CN2023/103985
Authority: WO
Inventors: 凌晨; 李国保; 杨勇杰; 吉亚明; 黑红旭; 胡卓超; 姜全力; 马长松; 吴美洪; 赵自鹏
Original assignee: 宝山钢铁股份有限公司
Priority date: 2022-06-30
Filing date: 2023-06-29
Publication date: 2024-01-04
Also published as: CN117363963A

Abstract

Disclosed in the present invention is an oriented silicon steel, comprising, in addition to 90% or more of Fe and inevitable impurities, the following chemical elements in percentages by mass: C: 0.020-0.080%, Si: 2.00-4.50%, Mn: 0.01-0.10%, S ≤0.005%, acid-soluble Al: 0.010-0.040%, N: 0.002-0.015%, Nb: 0.006-0.120%, and at least one selected from P: 0.01-0.10%, Sn: 0.01-0.30%, and Cu: 0.01-0.50%. Further disclosed in the present invention is a manufacturing method for the oriented silicon steel, the method comprising: smelting and casting; heating; hot rolling; cold rolling; decarburization annealing; nitriding; coating of an annealing separant; high-temperature annealing; and coating of an insulating coating and scoring. The oriented silicon steel and the manufacturing method therefor of the present invention are environmentally friendly and low in terms of energy consumption, realize high-level matching between a high magnetic induction intensity and a low magnetostriction, and have very wide application prospects.

Description

Oriented silicon steel and its manufacturing method

Technical field

The present invention relates to a oriented silicon steel and a manufacturing method thereof, in particular to a oriented silicon steel with low magnetostriction and a manufacturing method thereof.

Background technique

Grain-oriented silicon steel is a soft magnetic material characterized by sharp {110}<001> orientation (i.e. Gaussian grains). Oriented silicon steel is often used to make transformer cores and is an important functional material for making transformer cores.

In the existing technology, according to the difference in magnetic properties and Gauss grain orientation, oriented silicon steel can be divided into ordinary oriented silicon steel (referred to as CGO) and high magnetic induction oriented silicon steel (referred to as Hi-B); compared with CGO silicon steel, Hi -B silicon steel has lower iron loss, higher magnetic induction intensity and smaller magnetostriction. In recent years, as the noise performance of transformers has received increasing attention, the noise performance of transformers has become an indicator that manufacturers focus on. Since the magnetostriction of oriented silicon steel has a decisive influence on the noise performance of transformers, low magnetostriction oriented silicon steel has become a research hotspot.

In the production process of oriented silicon steel, the existing technology mainly reduces the magnetostriction of oriented silicon steel through the following three technical routes: 1) improving the Gauss grain orientation of the finished oriented silicon steel; 2) reducing the finished thickness of the oriented silicon steel; and 3) Apply high tension coating. All three technical routes can reduce the magnetostriction of oriented silicon steel.

CN111748731A (published on October 9, 2020, "Low magnetostrictive oriented silicon steel and manufacturing method thereof") produces localized structures due to local sequential structural arrangement by performing thermal stretching and magnetic annealing on the silicon steel substrate under specific conditions. The preferential orientation of the grains caused by magnetic inhomogeneity (rearrangement of the magnetic domain structure) increases the unidirectional magnetic anisotropy along the rolling direction (i.e., the volume of the 180° magnetic domain wall increases and the volume of the 90° magnetic domain wall decreases), This reduces the 90° magnetic domain volume of the finished oriented silicon steel, thereby reducing the magnetostriction of the oriented silicon steel, thereby reducing the overall noise level of the transformer. This application performs magnetic annealing under the following conditions: the magnetic annealing temperature is 750-200°C, the magnetic field direction is the rolling direction or transverse direction, and the magnetic field size is a DC magnetic field of 2500A/m + a pulse field of short-term pulse magnetic field of 50000A/m (50ms, 1 -10Hz). The L _v A (17/50) of the finished oriented silicon steel thus obtained is <55dB(A).

CN105220071A (published on January 6, 2016, "A low-noise characteristic oriented silicon steel and its manufacturing method") discloses a oriented silicon steel. In the oriented silicon steel substrate, 0.1%≤Cu≤0.5%, 0.01%≤S≤ 0.05%, and the atomic ratio Cu/S satisfies: 5≤Cu/S≤10. In the process of manufacturing this oriented silicon steel, the surface coating tension of the silicon steel and the grain size of the finished product are strictly controlled. The L _v A(17) of the finished oriented silicon steel made in this way is less than 55dB(A). The vibration generated by the transformer core made of this oriented silicon steel is small, and the overall noise level of the transformer is reduced.

CN107881411A (published on April 6, 2018, "A low-iron loss oriented silicon steel product for low-noise transformers and its manufacturing method") discloses a low-iron loss and low-noise oriented silicon steel. This application reduces iron loss and magnetostriction/reduces noise by strictly controlling the vertical reflectance R of the magnesium silicate bottom layer of the oriented silicon steel substrate to visible light to 40-60%, while ensuring uniform gloss of the magnesium silicate bottom layer. The magnetostrictive vibration noise value of the final product is less than 60dB(A), which is especially suitable for transformers.

It can be seen that magnetostriction can be reduced to a certain extent by controlling the 90° magnetic domain distribution and the coating tension level. However, both of the above methods require the use of additional equipment or conditions to reduce magnetostriction, and the reduction in magnetostriction is not significant. For example, although adding a magnetic field to affect the 90° magnetic domain in CN111748731A can increase the volume of the 180° magnetic domain wall, if the Gaussian texture of the oriented silicon steel substrate itself is not sharp enough, it will be difficult to reduce the amplitude of magnetostriction by adding external conditions later. Relatively limited. In addition, the method of refining magnetic domains by increasing coating tension also has the same problem, and this method also has extremely high requirements on coating performance. In addition, in some existing technologies, magnetostriction can be reduced to a certain extent by reducing the thickness of the silicon steel sheet. However, due to the higher silicon content of silicon steel, rolling silicon steel to a thinner thickness will be more difficult and will also result in increased costs.

Therefore, existing methods of reducing magnetostriction by increasing coating tension and reducing silicon steel thickness have great limitations. In contrast, by improving the Gaussian grain orientation of the oriented silicon steel itself (for example, by optimizing the chemical composition and adjusting the production process to improve the Gaussian grain orientation of the finished oriented silicon steel), that is, by reducing the deviation angle of the Gaussian grains, thus Increasing the magnetic induction intensity can fundamentally reduce the magnetostriction of grain-oriented silicon steel. In addition, in the context of the "double carbon" strategic goal, energy conservation and environmental protection are also one of the current focuses of the production process. How to ensure high-quality and stable production of grain-oriented silicon steel while reducing energy consumption will become one of the important research and development directions for grain-oriented silicon steel.

Based on the above reasons, the inventor hopes to develop a new type of oriented silicon steel with low magnetostriction and its manufacturing method. Through high-level design of the chemical composition of the oriented silicon steel and reasonable optimization of the production process, the production process will be green and On the basis of reducing consumption, it essentially increases the magnetic induction intensity of oriented silicon steel and reduces the magnetostriction of oriented silicon steel (by reducing the deviation angle of Gaussian grains), thus achieving high magnetic induction intensity and low magnetostriction of oriented silicon steel. Level matching.

Contents of the invention

Therefore, the main purpose of the present invention is to provide a oriented silicon steel and a manufacturing method thereof, which have excellent magnetic property matching (especially in terms of high magnetic induction intensity and low magnetostriction) while reducing energy consumption during the production process. Media consumption is significantly reduced.

In one aspect, the present application provides a oriented silicon steel, which, in addition to containing more than 90% Fe and unavoidable impurities, also contains the following chemical elements in mass percentage:

C: 0.020-0.080%, Si: 2.00-4.50%, Mn: 0.01-0.10%, S≤0.005%, acid-soluble Al: 0.010-0.040%, N: 0.002-0.015%, Nb: 0.006-0.120%, and At least one selected from the group consisting of P: 0.01-0.10%, Sn: 0.01-0.30%, and Cu: 0.01-0.50%.

Preferably, the oriented silicon steel contains the following chemical elements in mass percentage:

C: 0.020-0.080%, Si: 2.00-4.50%, Mn: 0.01-0.10%, S≤0.005%, acid-soluble Al: 0.010-0.040%, N: 0.002-0.015%, Nb: 0.006-0.120%, and At least one selected from P: 0.01-0.10%, Sn: 0.01-0.30% and Cu: 0.01-0.50%; the balance is Fe and inevitable impurities.

Preferably, the thickness of the oriented silicon steel is 0.15-0.30mm.

Preferably, the magnetic induction intensity B8 of the oriented silicon steel is >1.95T, and the magnetostrictive vibration speed sound pressure level L _v A <50dB (A).

On the other hand, the present application provides a method for manufacturing the above-mentioned oriented silicon steel, the method includes the following steps:

1) Smelting and casting molten steel to obtain slab;

2) Heating the slab;

3) Hot rolling, including rough rolling, coiling and holding and finishing rolling;

4) Cold rolling;

5) Decarburization annealing;

6) Nitriding;

7) Coating annealing isolating agent;

8) High temperature annealing;

9) Apply insulating coating and scoring to prepare oriented silicon steel.

Preferably, in step 1), the thickness of the slab is 180-250mm.

Preferably, in step 2), the heating temperature of the slab is 900-1150°C.

The acquired inhibitor process of nitriding treatment is used in this application, so the content of inhibitor elements in the slab is relatively low. The heating temperature in step 2) is conducive to reducing energy consumption while obtaining a sufficient amount of inhibitor. When the slab heating temperature is lower than 900°C, the inhibitor elements cannot be effectively dissolved; when the slab heating temperature is higher than 1150°C, energy consumption and the heat load of the heating furnace will increase. Therefore, the heating temperature of the slab in step 2) is preferably controlled to 900-1150°C.

Preferably, in step 3), the thickness of the intermediate billet after rough rolling is 35-50 mm.

Preferably, in step 3), the end temperature of rough rolling is higher than 950°C, the coiling temperature is 800-1050°C, the coiling time is 30-200s, and the start temperature of finishing rolling is lower than 1050°C.

This application sets the end temperature of rough rolling to higher than 950°C, which can ensure that the curling temperature is 800-1050°C, the coiling time is 30-200s, and the starting temperature of subsequent finishing rolling is lower than 1050°C. At this coiling temperature, the layers of the hot-rolled plate itself heat each other during the heat preservation process after coiling, so no additional heating is needed; and the coiling between rough rolling and finishing rolling can In order to make the structure of the hot-rolled plate more fully recrystallized, at the same time, some inhibitors can be dispersed and precipitated. When the coiling temperature is lower than 800℃ or the coiling time is less than 30s, the expected structural recrystallization effect of the hot rolled plate cannot be achieved; when the coiling temperature is higher than 1050℃ or the coiling time exceeds 200s, the crystallization of the intermediate billet will not be achieved. The granular structure and precipitated inhibitors will coarsen, adversely affecting the development of subsequent tissue and Gaussian texture. Therefore, it is preferable to set the temperature and/or time during hot rolling within the above range.

Preferably, normalized annealing treatment is performed between 3) hot rolling step and 4) cold rolling step. The normalized annealing temperature does not exceed 1000°C, preferably 800-1000°C, and more preferably 800-980°C. Normalized annealing The time is 20-200s.

By conducting extensive research, the inventor unexpectedly found that if the hot-rolled plate is conventionally normalized annealed at an annealing temperature of about 1100-1200°C according to the current existing technology, not only will it result in a normalized plate grain structure If it is too large, it will also cause the inhibitor to coarsen, eventually leading to the deterioration of the magnetic properties.

By coiling and insulating the rough rolled plate at a temperature of 800-1050°C, decarburization annealing can be achieved without subsequent normalization annealing treatment, or when normalization annealing treatment is performed at a normalization annealing temperature not exceeding 1000°C. The number of Gaussian grains with an offset angle of <3° in the final steel plate accounts for >10%, thereby obtaining a finished oriented silicon steel with the required Gaussian grain orientation and magnetic induction intensity. In contrast, if the rough rolled plate is not coiled and insulated, or the normalized annealing temperature after coiling and insulating is higher than 1000°C, the proportion of Gaussian grains with an offset angle of <3° in the steel plate after decarburization annealing will be significantly reduced (i.e. significantly less than 10%).

Preferably, in step 4), the cold rolling reduction ratio is >80%.

Preferably, in step 5), the decarburization annealing temperature is 800-900°C. When the decarburization annealing temperature is lower than 800°C, the decarburization effect will be insignificant; when the decarburization annealing temperature is higher than 900°C, the primary recrystallization grains will be too coarse, affecting the secondary recrystallization.

Preferably, in step 5), the proportion of Gaussian grains with an offset angle of <3° in the steel plate after decarburization annealing is >10%. In this article, "the proportion of Gaussian grains with an offset angle <3° in the steel plate after decarburization annealing" refers to the ratio (in %) of the number of Gaussian grains with an offset angle <3° to the total number of Gaussian grains.

As used herein, "deviation angle" refers to the Gaussian grain orientation deviation angle. The deviation angle and proportion of Gaussian grains were observed and counted by a scanning electron microscope with an electron backscatter diffraction (EBSD) system.

Preferably, in step 6), the nitriding amount is 50-280 ppm.

What is used in this application is the acquired inhibitor process of nitriding treatment. In other words, nitriding treatment must be performed before high-temperature annealing to form an inhibitor that is sufficient to inhibit the growth of primary recrystallized grains. When the nitriding amount is lower than 50ppm, the amount of inhibitors formed is insufficient; when the nitriding amount is higher than 280ppm, it will have a negative impact on the formation of the magnesium silicate bottom layer during high-temperature annealing. Based on these considerations, the nitriding amount in step 6) of the present invention is strictly controlled to 50-280 ppm.

In step 7), the annealing isolating agent can be an annealing isolating agent commonly used in the art, preferably MgO.

Preferably, in step 8), the annealing temperature is 1100-1250°C, and the annealing time is greater than 25 hours.

In step 9), the insulating coating can be formed using a coating liquid commonly used in the art, for example, by coating a coating liquid containing phosphate, colloidal silica and chromic anhydride; the insulating coating can be formed using this method for scoring. Commonly used scoring methods in the field, such as laser scoring, electrochemical scoring, toothed roller scoring, high-pressure water beam scoring, etc.

Compared with the existing technology, the oriented silicon steel and its manufacturing method of the present invention achieve the following beneficial effects:

The inventor found through a large number of experiments that the orientation of the Gaussian grain nuclei in the primary recrystallization has a decisive influence on the orientation of the Gaussian grains and the magnetic induction intensity of the finished product. Therefore, the inventor optimized the design of the relevant process parameters so that the proportion of Gaussian grains with deviation angles <3° in the steel plate after decarburization annealing was >10%, thereby obtaining the required Gaussian grain orientation and magnetic induction. Finished grain oriented silicon steel for strength.

On the premise of an environmentally friendly and consumption-reducing production process, the present invention obtains oriented silicon steel that matches high magnetic induction intensity and low magnetostriction at a high level. The oriented silicon steel of the present invention has excellent magnetic properties (magnetic induction intensity B8>1.95T, magnetostrictive vibration speed sound pressure level L _v A<50dB(A)), and has good economic benefits and application prospects.

Detailed ways

Through extensive research, the inventor unexpectedly discovered that by designing the chemical composition of oriented silicon steel as described above, oriented silicon steel with excellent comprehensive properties (especially high magnetic induction intensity and low magnetostriction) can be obtained. Specifically, the design principles of each of the above chemical elements are as follows. In this article, elemental contents are expressed in mass percent unless otherwise explicitly stated.

C: Adding an appropriate amount of element C can ensure that an appropriate proportion of γ phase is obtained during hot rolling or normalization, which is conducive to the precipitation of fine dispersion inhibitors. When the element C content in the steel is lower than 0.020%, the proportion of γ phase is low, which is not conducive to the precipitation of inhibitors; when the element C content in the steel is higher than 0.080%, the decarburization cost will increase. Based on these considerations, the content of element C in the oriented silicon steel of the present invention is controlled to 0.020-0.080%, preferably 0.022-0.073%.

Si: Element Si is the main element that reduces iron loss. In order to ensure the quality of finished silicon steel, the element Si content in the steel should not be too low or too high. When the element Si content in silicon steel is less than 2.00%, it is difficult for the resulting oriented silicon steel to obtain the required low iron loss; when the element Si content in the steel is higher than 4.50%, cold rolling will be difficult and the yield rate will be reduced. Based on these considerations, the content of element Si in the oriented silicon steel of the present invention is controlled to 2.00-4.50%, preferably 2.19-4.29%.

Mn: Adding an appropriate amount of element Mn can form a small amount of MnS auxiliary inhibitor during continuous casting and hot rolling, which can effectively improve the microstructure and rollability of grain-oriented silicon steel. In order to ensure the performance of grain-oriented silicon steel, the content of element Mn in the steel must be strictly controlled. When the Mn content is lower than 0.01%, it is not conducive to obtaining the required silicon steel microstructure and rolling properties; when the Mn content is higher than 0.10%, the slab heating temperature will increase significantly, and coarse MnS inhibitors will easily form. Based on these considerations, the content of element Mn in the oriented silicon steel of the present invention is controlled to 0.01-0.10%, preferably 0.01-0.09%.

S: Element S can form auxiliary inhibitors such as MnS and Cu ₂ S. However, it should be noted that the content of element S in steel should not be too high. When the element S content in steel is too high, it will significantly increase the slab heating temperature, which is not conducive to production. Based on these considerations, the content of element S in the grain-oriented silicon steel of the present invention is controlled to S≤0.005%, preferably ≤0.004%.

Acid-soluble Al: Acid-soluble Al is an important component in forming the main inhibitor AlN. When the acid-soluble Al content in the steel is lower than 0.010%, the inhibitor will be insufficient; when the acid-soluble Al content in the steel is higher than 0.040%, the inhibitor AlN will be coarse. Therefore, the content of acid-soluble Al in silicon steel needs to be strictly controlled. Based on these considerations, the content of acid-soluble Al in the oriented silicon steel of the present invention is controlled to 0.010-0.040%, preferably 0.012-0.039%.

N: Adding an appropriate amount of element N can appropriately suppress grain growth. The element N added to silicon steel can cooperate with acid-soluble Al to form AlN before nitriding, thereby effectively inhibiting the growth of primary recrystallized grains. When the element N content in steel is lower than 0.002%, the growth of primary recrystallized grains cannot be effectively suppressed; when the element N content in steel is higher than 0.015%, it will significantly increase the difficulty of steelmaking. Based on these considerations, the content of element N in the oriented silicon steel of the present invention is controlled to 0.002-0.015%, preferably 0.003-0.014%.

Nb: In order to reduce the slab heating temperature, the content of elements Mn and Cu is relatively low, but this will lead to insufficient precipitation of MnS and Cu ₂ S. Therefore, in order to make up for the problem of insufficient inhibitory ability of inhibitors, an appropriate amount of element Nb is added to silicon steel. Element Nb can form an auxiliary inhibitor Nb(C,N) and play the role of an auxiliary inhibitor. In addition, since the solid solution temperature of Nb(C,N) is relatively low, it can also reduce the slab heating temperature. When the element Nb content in the steel is lower than 0.006%, the inhibitor Nb(C,N) formed cannot fully exert its inhibitory effect; when the element Nb content in the steel is higher than 0.120%, the inhibitory effect is too strong and hinders the secondary recycling. Crystallization occurs. Based on these considerations, the content of element Nb in the oriented silicon steel of the present invention is controlled to 0.006-0.120%, preferably 0.006-0.118%.

P and Sn: The elements P and Sn are both grain boundary segregation elements. Adding appropriate amounts of elements P and Sn to silicon steel can act as auxiliary inhibitors. When the content of the elements P and Sn in the steel is less than 0.01% respectively, the auxiliary inhibitory effect cannot be fully exerted; when the content of the elements P and Sn in the steel is higher than 0.10% and 0.30% respectively, it will be detrimental to decarburization and nitriding. Influence. Based on these considerations, the content of element P in the grain-oriented silicon steel of the present invention is controlled to 0.01-0.10%, preferably 0.02-0.08%, and the content of element Sn is controlled to 0.01-0.30%, preferably 0.02-0.25%.

Cu: Adding an appropriate amount of element Cu to silicon steel can not only form auxiliary inhibitors such as Cu ₂ S, but also effectively expand the γ phase region, thereby facilitating the precipitation of other inhibitors. However, it should be noted that the elemental Cu content in steel should not be too low or too high. When the element Cu content in silicon steel is less than 0.01%, the above effects cannot be fully exerted; when the element Cu content in silicon steel is higher than 0.50%, production costs will increase. Based on these considerations, the content of element Cu in the grain-oriented silicon steel of the present invention is controlled to 0.01-0.50%, preferably 0.02-0.48%, such as 0.02-0.39%.

The oriented silicon steel and its manufacturing method according to the present invention will be further explained and described below with reference to specific examples. However, the following description is an illustrative description for explaining the present invention and is not intended to limit the technical scope of the present invention to the description range.

Examples 1-12

The oriented silicon steel of Examples 1-12 of the present invention is prepared through the following steps:

1) According to the formula shown in Table 1 below, smelt and cast the molten steel to obtain a slab with a thickness of 180-250mm.

2) Heat the slab at a temperature of 900-1150°C.

3) Carry out rough rolling, coiling insulation and finish rolling on the slab: the end temperature of rough rolling is higher than 950℃, the coiling temperature is 800-1050℃, the coiling time is 30-200s, and the starting temperature of finish rolling is lower than 1050℃.

4) Cold rolling to a finished plate thickness of 0.15-0.30mm, where the cold rolling reduction ratio is >80%.

5) Carry out decarburization annealing at a temperature of 800-900°C.

6) Nitriding, in which the nitriding amount is 50-280ppm.

7) Apply annealing release agent.

8) High temperature annealing, where the annealing temperature is 1100-1250°C and the annealing time is greater than 25 hours.

9) Apply insulating coating and scoring to prepare oriented silicon steel with a thickness of 0.15-0.30mm.

It should be noted that other embodiments except Example 10 and Example 11 also perform normalizing annealing treatment between steps 3) and 4) (the normalizing annealing temperature does not exceed 1000°C, and the normalizing annealing time is 20-200 s. ).

Comparative Example 1-20

Comparative Examples 1-20 adopt similar process steps to prepare grain-oriented silicon steel, and the other comparative examples except Comparative Example 16 also perform normalized annealing treatment between steps 3) and 4). However, the chemical element composition and process parameters of the oriented silicon steel in Examples 1-12 all meet the scope of protection required by the present invention, while at least one of the chemical element composition and/or process parameters in Comparative Examples 1-20 does not meet the requirements of the present invention. Scope of protection claimed.

Table 1 lists the chemical compositions of the grain-oriented silicon steels of Examples 1-12 and Comparative Examples 1-20.

Table 1 (wt%, balance is Fe and inevitable impurities)

The specific process parameters in the above process steps of Examples 1-12 and Comparative Examples 1-20 are listed in Table 2-1 and Table 2-2.

table 2-1

Table 2-2

In step 5), the decarburized annealed steel plates of Examples 1-12 and Comparative Examples 1-20 are sampled, and then the deviation angle of each sample is < The proportion of 3° Gaussian grains was observed and analyzed.

Table 3 lists the proportion of Gaussian grains with deviation angles <3° in the decarburized annealed steel plates of Examples 1-12 and Comparative Examples 1-20.

table 3

As shown in Table 3, the proportion of Gaussian grains with an offset angle <3° in the decarburized annealed steel plates of Examples 1-12 is 11%-22%. In Comparative Example 1-20, the proportion of Gaussian grains with an offset angle <3° in the decarburized annealed steel plate is 3.6%-9.4%, which is significantly lower than that of Example 1-12.

The finished oriented silicon steel products prepared in Examples 1-12 and Comparative Examples 1-20 were sampled, and the magnetic properties of each sample were measured and analyzed to obtain the magnetic induction intensity B8 and magnetostrictive vibration velocity and sound pressure of each oriented silicon steel sample. Level L _v A.

In this article, the relevant magnetic property testing methods of grain-oriented silicon steel are as follows:

Magnetic property test: According to the national standard GB/T 13789-2008 "Method for measuring the magnetic properties of electrical steel sheets (strips) using a single-chip tester", the magnetic induction intensity of the oriented silicon steel of Examples 1-12 and Comparative Examples 1-20 Make a determination.

Magnetostriction test: According to IEC technical report IEC/TP 62581, using a non-contact laser Doppler vibrometer, the compressive stress experienced by oriented silicon steel is at B=1.7T, f=2MPa (in the actual working conditions of the transformer) Under the condition of 2-3MPa), the magnetostrictive vibration velocity and sound pressure level L _v A of the oriented silicon steels of Examples 1-12 and Comparative Examples 1-20 were measured. In this article, L _v A refers to the magnetostrictive vibration velocity sound pressure level of oriented silicon steel under the above test conditions, in dB(A).

Table 4 lists the magnetic induction intensity B8 and the magnetostrictive vibration speed sound pressure level L _v A of the oriented silicon steels of Examples 1-12 and Comparative Examples 1-20.

Table 4

As shown in Table 4, the magnetic induction intensity B8 of Examples 1-12 is 1.954-1.972T, and the magnetostrictive vibration speed sound pressure level L _v A is 43-48dB(A). The magnetic induction intensity B8 of Comparative Example 1-20 is 1.805-1.939T (obviously lower than that of Example 1-12), and the magnetostrictive vibration speed sound pressure level L _v A is 51-64dB(A) (obviously higher than that of Example 1-12). 1-12).

It can be seen from Tables 1 to 4 that the proportion of Gaussian grains with deviation angles <3° in the decarburized annealed steel plates of Examples 1-12 is significantly higher than that of Comparative Examples 1-20, and its magnetic properties (especially magnetic induction intensity B8 and L _v A) are significantly better than Comparative Examples 1-20.

After analyzing the proportion of Gaussian grains with deviation angles <3° in the decarburized annealed steel plate, the inventor unexpectedly found that different combinations of hot rolling and normalized annealing process parameters have an impact on the decarburized annealed steel plate. The Gaussian grain orientation deviation angle α has a key influence. Especially when it is within the chemical element composition range required by the present invention, by coiling and insulating the rough rolled plate at a temperature of 800-1050°C, and subsequently performing low-temperature normalized annealing (the normalized annealing temperature does not exceed 1000°C), or even Without normalizing annealing treatment, the proportion of Gaussian grains with deviation angles <3° in the steel plate after decarburization annealing can be significantly increased. The inventor found through a large number of experiments that the orientation of the Gaussian grain nuclei in the primary recrystallization has a decisive influence on the orientation of the Gaussian grains and the magnetic induction intensity of the finished product. Therefore, the oriented silicon steel produced by the method of the present invention shows a high level of matching of high magnetic induction intensity and low magnetostriction.

It should be noted that all technical features recorded in this application can be freely combined or combined in any way, unless they conflict with each other. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention. For example, features shown or described as part of one embodiment can be used with another embodiment to produce yet a still further embodiment. Thus, it is intended that the present invention cover the modifications and variations provided they come within the scope of the appended claims and their equivalents.

Claims

A kind of oriented silicon steel, characterized in that, in addition to containing more than 90% Fe and inevitable impurities, the oriented silicon steel also contains the following chemical elements in mass percentage:

C: 0.020-0.080%, Si: 2.00-4.50%, Mn: 0.01-0.10%, S≤0.005%, acid-soluble Al: 0.010-0.040%, N: 0.002-0.015%, Nb: 0.006-0.120%, and At least one selected from the group consisting of P: 0.01-0.10%, Sn: 0.01-0.30%, and Cu: 0.01-0.50%.
The oriented silicon steel according to claim 1, characterized in that the oriented silicon steel contains the following chemical elements in mass percentage:

C: 0.020-0.080%, Si: 2.00-4.50%, Mn: 0.01-0.10%, S≤0.005%, acid-soluble Al: 0.010-0.040%, N: 0.002-0.015%, Nb: 0.006-0.120%, and At least one selected from P: 0.01-0.10%, Sn: 0.01-0.30% and Cu: 0.01-0.50%; the balance is Fe and inevitable impurities.
The oriented silicon steel according to claim 1 or 2, characterized in that the thickness of the oriented silicon steel is 0.15-0.30mm; preferably, the magnetic induction intensity B8 of the oriented silicon steel>1.95 T, the magnetostrictive vibration speed sound pressure Level L v A＜50dB(A).
The method for manufacturing the oriented silicon steel according to any one of claims 1-3, the method includes the following steps:

1) Smelting and casting molten steel to obtain slab;

2) Heating the slab;

3) Hot rolling, including rough rolling, coiling and holding and finishing rolling;

4) Cold rolling;

5) Decarburization annealing;

6) Nitriding;

7) Coating annealing isolating agent;

8) High temperature annealing;

9) Apply insulating coating and scoring to prepare oriented silicon steel.
The method according to claim 4, characterized in that in step 3), the end temperature of rough rolling is higher than 950°C, the coiling temperature is 800-1050°C, the coiling time is 30-200s, and the finish rolling starts The temperature is lower than 1050℃.
The method according to claim 4, characterized in that a normalized annealing treatment is performed after step 3) and before step 4), and the normalized annealing temperature does not exceed 1000°C, preferably 800-1000°C, and more preferably 800-800°C. 980℃, normalized annealing time is 20-200s.
The method according to any one of claims 4 to 6, characterized in that in step 2), the heating temperature of the slab is 900-1150°C.
The method according to any one of claims 4-6, characterized in that the method satisfies more than one of the following conditions:

In step 1), the thickness of the slab is 180-250mm;

In step 3), the thickness of the intermediate billet after rough rolling is 35-50mm;

In step 4), the cold rolling reduction ratio is >80%; and

In step 7), the annealing isolating agent is MgO.
The method according to any one of claims 4 to 6, characterized in that in step 5), the decarburization annealing temperature is 800-900°C; preferably, the deviation angle in the steel plate after decarburization annealing is <3°. The proportion of Gaussian grains is >10%.
The method according to any one of claims 4-6, characterized in that in step 6), the nitriding amount is 50-280 ppm.
The method according to any one of claims 4 to 6, characterized in that in step 8), the annealing temperature is 1100-1250°C, and the annealing time is greater than 25 hours.