Oriented silicon steel and manufacturing method thereof

Abstract

The invention discloses oriented silicon steel, which contains Fe and inevitable impurity elements, and further contains the following chemical elements in percentage by mass: 0.02 to 0.08 percent of C, 2.0 to 4.5 percent of Si, 0.02 to 0.30 percent of Mn, 0 < S < = 0.0050 percent, 0.01 to 0.04 percent of Als, 0.002 to 0.01 percent of N, 0.005 to 0.08 percent of Nb and the balance of Fe. 0.01% to 0.30% of Sb; 0.01% to 0.30% of Cr; 0.01% to 0.60% of Bi; and at least one of the following components in percentage by weight: 0.01 to 0.1 percent of P, 0.01 to 0.30 percent of Sn and 0.01 to 0.50 percent of Cu. Correspondingly, the invention further discloses a manufacturing method of the oriented silicon steel. The oriented silicon steel not only has excellent magnetic performance, but also has low magnetostriction.

Description

Technical Field

[0001] The present invention relates to a steel material and a manufacturing method thereof, and in particular to an oriented silicon steel and a manufacturing method thereof. Background Art

[0002] As we all know, oriented silicon steel is a kind of sharp {110} <001> Oriented silicon steel is a soft magnetic material characterized by grains with Gauss orientation. Its production process is long and the production process is complex and strict. Oriented silicon steel is often used to manufacture transformer cores and is an important functional material for manufacturing transformer cores.

[0003] In the prior art, oriented silicon steel can be divided into common oriented silicon steel (CGO for short) and high magnetic induction oriented silicon steel (Hi-B for short) according to the magnetic properties and Gaussian grain orientation. Compared with CGO steel, Hi-B steel has lower iron loss, higher magnetic induction and smaller magnetostriction.

[0004] At present, the high magnetic steel oriented silicon steel in the prior art generally adopts two technical routes: one route is the "inherent inhibitor method", that is, by heating the ingot at high temperature (1350-1400℃), the inhibitor-forming elements are dissolved, and then precipitated in a fine and dispersed manner during the hot rolling and normalizing process to obtain sufficient inhibitors and inhibition capacity; the other route is the "obtained inhibitor method", that is, by adjusting the inhibitor element content, the ingot is heated at low temperature (1100-1250℃), and some inhibitors are precipitated during the hot rolling and normalizing process, and then new inhibitors are obtained through the nitriding process before high-temperature annealing to meet the inhibition capacity required for secondary recrystallization during high-temperature annealing.

[0005] Compared with the "inherent inhibitor method", the "acquired inhibitor method" has the advantages of low billet heating temperature, good billet surface quality, low equipment energy consumption and stable magnetic properties of the finished product. Therefore, the "acquired inhibitor method" using low-temperature billet heating is also a hot topic of research for domestic and foreign oriented silicon steel manufacturers.

[0006] For example, the Chinese patent document with the publication number CN102471819A and the publication date May 23, 2012, entitled "Manufacturing method of directional electromagnetic steel sheet", discloses a method for producing oriented silicon steel using a hot coil box process, wherein the steel billet is heated at 1100-1150°C before hot rolling, and the oriented silicon steel intermediate billet is coiled at 800-1000°C after hot rolling rough rolling, and the heat preservation is controlled for more than 300S, and then the oriented silicon steel intermediate billet is finely rolled at less than 1000°C; after fine rolling, the steel is decarburized, annealed, and nitrided, with a nitriding amount of 220ppm, and then high-temperature annealed to obtain the finished product. Using this technical solution, the study found that the precipitation morphology of the inhibitor can be effectively controlled by coiling and heat preservation, so that the steel type B is precipitated on MnS or MnSe in the form of BN composite, ensuring that the primary recrystallization grains are small and uniform, and ensuring the stability of the magnetic properties. The method increases the hot coil box process, controls the precipitation of inhibitors and the size of primary recrystallization, thereby ensuring stable production of the product.

[0007] Another example: the Chinese patent document with publication number CN104726763A, publication date June 24, 2015, and titled "A hot rolling method for electrical steel", discloses a hot rolling method for electrical steel, which adopts adding hot coil boxes with heating function before and after the rolling mill, and controls the thickness of the ingot to be 30-300mm, controls the heating temperature of the slab to be 950-1180℃, controls the end temperature of rough rolling to be 900-1000℃, controls the thickness of the intermediate ingot to be 10-45mm, and controls the end temperature of finishing rolling to be 850-1000℃. The invention aims to use the hot coil box insulation between each pass in the hot rolling stage to reduce the heating temperature of the slab, control the solid solution precipitation of the inhibitor, and alleviate the problem of uneven temperature at the head and tail of the hot coil, while reducing the heating temperature of the ingot to ensure stable product performance.

[0008] Another example: the Chinese patent document with publication number CN101210297A, publication date July 2, 2008, and titled "A method for manufacturing oriented silicon steel", discloses a method for producing oriented silicon steel using a hot coil box after hot rolling, wherein the temperature of the strip entering the finishing mill is controlled to be 1100-1250°C, the finishing outlet temperature is greater than 800°C, and laminar cooling is used after rolling. The hot rolling method can control the precipitation state of inhibitors during continuous casting, and ensure uniform product performance through high-temperature, short-time, and rapid hot rolling heating process.

[0009] It can be seen from the above patent documents that the hot coil box process is beneficial to the uniformity of hot-rolled structure of oriented silicon steel and the control of inhibitor precipitation, and can promote the stability of magnetic properties of oriented silicon steel; the above patents also use hot coil box technology to pursue stable production of oriented silicon steel, but have not significantly improved magnetic properties. From the perspective of ensuring the stability of magnetic properties, for oriented silicon steel production enterprises with a high production level, it is entirely possible to ensure the uniformity and stability of magnetic properties of oriented silicon steel through precise control of steelmaking ingredients and reasonable deployment of post-process technology, without the need to use hot coil box technology.

[0010] In addition, ensuring that oriented silicon steel has excellent magnetic properties while having low magnetostriction is also an important research and development direction for oriented silicon steel. However, the above existing technologies do not reduce the magnetostriction of oriented silicon steel. Summary of the invention

[0011] One of the objects of the present invention is to provide a oriented silicon steel having excellent magnetic properties and low magnetostriction.

[0012] In order to achieve the above object, the present invention provides a oriented silicon steel, which contains Fe and inevitable impurity elements, and further contains the following chemical elements in the following mass percentages:

[0013] C: 0.02~0.08%, Si: 2.0~4.5%, Mn: 0.02~0.30%, S≤0.0050%, Als: 0.01~0.04%, N: 0.002~0.01%, Nb: 0.005~0.08%; Sb: 0.01~0.30%; Cr: 0.01~0.30%; Bi: 0.01~0.60%; and at least one of P: 0.01~0.1%, Sn: 0.01~0.30%, and Cu: 0.01~0.50%.

[0014] Furthermore, in the oriented silicon steel of the present invention, the mass percentage of each chemical element is:

[0015] C: 0.02~0.08%, Si: 2.0~4.5%, Mn: 0.02~0.30%, S≤0.0050%, Als: 0.01~0.04%, N: 0.002~0.01%, Nb: 0.005~0.08%; Sb: 0.01~0.30%; Cr: 0.01~0.30%; Bi: 0.01~0.60%; and at least one of P: 0.01~0.1%, Sn: 0.01~0.30%, and Cu: 0.01~0.50%; the balance is Fe and other inevitable impurities.

[0016] In the oriented silicon steel of the present invention, the design principles of each chemical element are specifically described as follows:

[0017] C: In the oriented silicon steel described in the present invention, adding an appropriate amount of C element can ensure that an appropriate proportion of γ phase is obtained during the hot rolling and normalizing process, which is conducive to the precipitation of inhibitors. When the C content in the steel is lower than 0.02%, the γ phase ratio is low, which is not conducive to the precipitation of inhibitors; and when the C content in the steel is higher than 0.08%, the decarburization cost will increase. Based on this, in the oriented silicon steel described in the present invention, the mass percentage of C element can be controlled between 0.02 and 0.08%.

[0018] Si: In the oriented silicon steel described in the present invention, Si is the main element for reducing iron loss. In order to ensure the quality of the finished steel, the Si content in the steel should not be too low. When the Si content in the steel is lower than 2.0%, it is difficult to reduce the iron loss of the steel. Correspondingly, the Si content in the steel should not be too high. When the Si content in the steel is higher than 4.5%, it will cause difficulties in cold rolling and reduce the yield rate. Based on this, in the oriented silicon steel described in the present invention, the mass percentage of the Si element can be controlled between 2.0 and 4.5%.

[0019] Mn: In the oriented silicon steel of the present invention, adding an appropriate amount of Mn element can effectively improve the structure and rollability of the oriented silicon steel. In order to ensure the performance of the oriented silicon steel, the mass percentage of the Mn element in the oriented silicon steel of the present invention can be controlled between 0.02 and 0.30%.

[0020] S: In the oriented silicon steel described in the present invention, S element can form MnS, Cu 2 S is an auxiliary inhibitor. However, it should be noted that the S content in the steel should not be too high. When the S content in the steel is too high, the heating temperature of the casting billet will be significantly increased, which is not conducive to production. Based on this, in the oriented silicon steel described in the present invention, the mass percentage of the S element can be controlled to 0<S≤0.0050%.

[0021] Als: In the oriented silicon steel described in the present invention, Als is an important element, which is an important element for forming the main inhibitor AlN. It should be noted that when the Als content in the steel is too high, the inhibitor AlN will become coarse; when the Als content in the steel is too low, the inhibitory force will be insufficient. Therefore, it is necessary to strictly control the content of Als in the steel. In the oriented silicon steel described in the present invention, the mass percentage of Als can be controlled between 0.01 and 0.04%.

[0022] N: In the oriented silicon steel described in the present invention, adding an appropriate amount of N element can inhibit the growth of grains. The N element added to the steel can cooperate with the Als element to form AlN before nitriding, thereby effectively inhibiting the growth of primary recrystallized grains. When the N content in the steel is lower than 0.002%, the growth of primary recrystallized grains cannot be effectively inhibited; when the N content in the steel is higher than 0.01%, the difficulty of steelmaking will be greatly increased. Based on this, in the oriented silicon steel described in the present invention, the mass percentage of the N element can be controlled between 0.002 and 0.01%.

[0023] Nb: In the oriented silicon steel described in the present invention, the Nb element can form an auxiliary inhibitor Nb (C, N), which plays the role of an auxiliary inhibitor; in addition, since the solid solution temperature of Nb (C, N) is relatively low, it can also play a role in reducing the heating temperature of the ingot. When the Nb element content in the steel is too low, the inhibitory effect of the formed inhibitor Nb (C, N) is not obvious; when the Nb element content in the steel is too high, the inhibitory force is too strong, which hinders the occurrence of secondary recrystallization. Based on this, in the oriented silicon steel described in the present invention, the mass percentage of the Nb element can be controlled between 0.005 and 0.08%.

[0024] In the oriented silicon steel described in the present invention, P, Sn, Sb, Cr, and Bi are all grain boundary segregation elements. Adding an appropriate amount of P, Sn, Sb, Cr, and Bi elements in the steel can play the role of auxiliary inhibitors. When the content of P, Sn, Sb, Cr, and Bi elements in the steel is too high, it will have an adverse effect on decarburization and nitriding; when the content of P, Sn, Sb, Cr, and Bi elements in the steel is too low, the auxiliary inhibitory effect is not obvious. Therefore, in the oriented silicon steel described in the present invention, when containing the above elements, the mass percentage of P element can be controlled between 0.01 and 0.1%, the mass percentage of Sn element can be controlled between 0.01 and 0.30%, the mass percentage of Sb element can be controlled between 0.01 and 0.30%, the mass percentage of Cr element can be controlled between 0.01 and 0.30%, and the mass percentage of Bi element can be controlled between 0.01 and 0.60%.

[0025] In the present invention, adding an appropriate amount of Cu element to the steel can not only form Cu 2S is an auxiliary inhibitor and can also effectively expand the γ phase region, which is beneficial to the precipitation of other inhibitors. However, it should be noted that the Cu content in the steel should not be too high. When the Cu content in the steel is higher than 0.5%, the production cost will increase; accordingly, the Cu content in the steel should not be too low. When the Cu content in the steel is lower than 0.01%, its role is not obvious. Based on this, in the oriented silicon steel described in the present invention, when Cu is contained, the mass percentage of the Cu element can be controlled between 0.01 and 0.50%.

[0026] Furthermore, in the oriented silicon steel of the present invention, the average diameter D of the secondary recrystallized grains in the finished product is less than 12 mm.

[0027] In the present invention, in order to make the final product have excellent magnetic properties, especially lower magnetostriction, the average diameter D of the secondary recrystallized grains of the final product must be controlled to be less than 12 mm.

[0028] Furthermore, in the oriented silicon steel of the present invention, the magnetic induction B 800 ≥1.95T, its iron loss P 17 / 50 ≤0.74W / kg, magnetostriction L v A≤50dB.

[0029] Furthermore, in the oriented silicon steel described in the present invention, its thickness is 0.10-0.30 mm.

[0030] Correspondingly, another object of the present invention is to provide a method for manufacturing the above-mentioned oriented silicon steel. On the basis of the "inhibitor acquisition method" of low-temperature ingot heating, the method gives full play to the positive effects of the hot coil box process and grain boundary segregation elements on the uniformity of the structure of the oriented silicon steel hot-rolled plate and the inhibitor effect, and combines the control of the grain size of the hot-rolled plate and the normalized plate to further improve the magnetic properties of the oriented silicon steel, while reducing the energy consumption of the production process, so that the entire production process has the characteristics of high efficiency and energy saving.

[0031] In order to achieve the above object, the present invention provides a method for manufacturing oriented silicon steel, which comprises the steps of:

[0032] (1) obtaining a slab;

[0033] (2) Slab heating;

[0034] (3) Hot rolling, which includes: rough rolling, coiling and heat preservation in a hot coil box, and finishing rolling; wherein the rough rolling end temperature is higher than 960°C; the coiling temperature is 830-1060°C, and the coiling time is 30-200s; the finishing rolling start temperature is lower than 1050°C; the average diameter of the recrystallized grains on the surface of the hot rolled plate is d 1 >40μm;

[0035] (4) Normalizing annealing, the normalizing annealing temperature is 600-1000°C, and the average diameter of the recrystallized grains on the surface of the normalized plate is obtained. 2 >120μm;

[0036] (5) Cold rolling;

[0037] (6) Decarburization annealing;

[0038] (7) Nitriding;

[0039] (8) Applying annealing isolation agent;

[0040] (9) High temperature annealing;

[0041] (10) Insulation coating and laser scoring.

[0042] Through a large number of experimental studies and analyses, the inventors found that coiling and heat preservation in a suitable temperature range after rough rolling of the hot rolled coil can ensure the advantages of small temperature difference between the head and tail of the hot rolled coil, more sufficient dispersion and precipitation of inhibitors and more complete recrystallization of grains in the hot rolled plate structure, and the heat preservation after coiling is completely heated by the layers of the rough rolled coil itself, without the need for additional heating. If the coiling temperature is higher than 1060°C, or the coiling time is greater than 200s, the grain structure of the intermediate billet and the inhibitors that have been precipitated will coarsen, which will have an adverse effect on the development of subsequent structures.

[0043] In addition, the inventors studied the microstructure evolution under different hot rolling and normalizing processes and found that after the hot rolled plate was coiled at 830-1060℃, the surface layer (from the surface to 1 / 8 of the plate thickness) of the hot rolled plate and the normalized plate was recrystallized perfectly under the condition of subsequent normalizing annealing temperature of 600-1000℃. Among them, the average grain diameter of the recrystallized microstructure of the surface layer of the hot rolled plate was d 1 >40μm, the average diameter of the recrystallized grains on the surface of the normalized plate is d 2 >120μm. Accordingly, if the hot-rolled plate is not coiled and heat-insulated or the normalizing annealing temperature after coiling and heat-insulating is higher than 1000℃ or lower than 600℃, the grain diameter of the surface structure of the hot-rolled plate and the normalized plate cannot reach the ideal size or the two do not form a good match, resulting in poor magnetic properties of the final product.

[0044] In addition, in the technical solution described in the present invention, in step (3), since the intermediate coiling process is added during the hot rolling of the hot-rolled plate, the surface recrystallization structure of the hot-rolled plate is more complete and some inhibitors are dispersed and precipitated. Therefore, the normalizing annealing temperature of the normalizing step in step (4) cannot be too high. If annealing is performed according to the conventional normalizing annealing process (1100-1200°C), not only will the grain structure of the normalized plate be too large, but also the inhibitors will be coarsened, which will eventually lead to the deterioration of magnetic properties.

[0045] In step (8) of the present invention, it is necessary to coat the nitrided plate with an annealing separator, and the annealing separator used can be MgO.

[0046] Furthermore, in the method for manufacturing oriented silicon steel of the present invention, the average diameter d1 of the recrystallized grains on the surface of the hot-rolled plate obtained after step (3) is greater than 40 μm.

[0047] Furthermore, in the method for manufacturing oriented silicon steel of the present invention, the average diameter d2 of the recrystallized grains on the surface of the normalized plate obtained after step (4) is greater than 120 μm.

[0048] Furthermore, in the method for manufacturing oriented silicon steel of the present invention, the average diameter of the recrystallized grains on the surface of the hot-rolled plate is d 1 and the average diameter of recrystallized grains on the surface of the normalized plate d 2 Satisfaction:d 1 +d 2 <300μm.

[0049] In this embodiment, the average diameter d1 of the recrystallized grains on the surface of the hot-rolled plate and the average diameter d2 of the recrystallized grains on the surface of the normalized plate are controlled to satisfy: d1+d2<300 μm, which can further form a perfect match between the hot-rolled plate structure and the normalized plate structure.

[0050] Furthermore, in step (2) of the method for manufacturing oriented silicon steel of the present invention, the slab heating temperature is 900-1150°C.

[0051] In the technical solution described in the present invention, since the "inhibitor acquisition method" is adopted, the inhibitor element content in the cast billet is relatively low, so in the slab heating process in step (2), the slab heating temperature can be controlled between 900 and 1150°C. This is because: if the slab heating temperature is higher than 1150°C, it will not only increase energy consumption, but also increase the heat load of the heating furnace; if the slab heating temperature is lower than 900°C, the inhibitor element cannot be effectively dissolved.

[0052] Furthermore, in step (4) of the method for manufacturing oriented silicon steel of the present invention, the normalizing annealing time is controlled to be 20 to 200 seconds.

[0053] Furthermore, in step (5) of the method for manufacturing oriented silicon steel of the present invention, the cold rolling reduction ratio is controlled to be greater than 80%.

[0054] Furthermore, in step (6) of the method for manufacturing oriented silicon steel of the present invention, the decarburization annealing temperature is 800-900°C.

[0055] In the technical solution described in the present invention, the decarburization annealing temperature in the decarburization annealing process of step (6) can be controlled to be 800-900°C. This is because: when the decarburization annealing temperature is higher than 900°C, the primary recrystallization grains will be too coarse, affecting the secondary recrystallization; and when the decarburization annealing temperature is lower than 800°C, the decarburization effect will be insignificant.

[0056] Furthermore, in step (7) of the method for manufacturing oriented silicon steel of the present invention, the nitriding amount is 50 to 280 ppm.

[0057] In the technical solution described in the present invention, since the process route of "obtaining inhibitor method" is adopted, nitriding treatment must be carried out before high-temperature annealing to form inhibitors that can inhibit the growth of primary recrystallized grains. In step (7), when the nitriding amount is less than 50 pm, the amount of inhibitor formed is insufficient; when the nitriding amount is higher than 280 ppm, it has an adverse effect on the formation of magnesium silicate bottom layer during high-temperature annealing. Therefore, in the nitriding process of step (7) described in the present invention, the nitriding amount can be controlled between 50 and 280 ppm.

[0058] Furthermore, in step (9) of the method for manufacturing oriented silicon steel of the present invention, the high temperature annealing temperature is 1100-1250° C., and the annealing time is greater than 25 hours.

[0059] Compared with the prior art, the oriented silicon steel and the manufacturing method thereof described in the present invention have the following advantages and beneficial effects:

[0060] The manufacturing method of the oriented silicon steel described in the present invention is based on the "inhibitor acquisition method" of low-temperature ingot heating, and fully utilizes the positive effects of the hot coil box process and the boundary segregation elements on the uniformity of the hot-rolled plate structure and the inhibitor effect of the oriented silicon steel, and combines the best normalizing process with the control of the grain size of the surface structure of the hot-rolled plate or the normalized plate, so as to further improve the magnetic properties of the oriented silicon steel, reduce magnetostriction, and reduce the energy consumption of the production process, so that the entire production process has the characteristics of high efficiency and energy saving.

[0061] The present invention adopts a reasonable chemical element composition design and cooperates with an optimized manufacturing process to obtain oriented silicon steel with higher magnetic properties and lower magnetostriction on the basis of energy saving and consumption reduction, stable production and improved production efficiency.

[0062] In some embodiments, the magnetic induction B of the oriented silicon steel of the present invention is 800 ≥1.95T, its iron loss P 17 / 50 ≤0.74W / kg, magnetostriction L v A≤50dB, it has excellent performance and can be effectively used to manufacture transformer cores, with good promotion prospects and application value. DETAILED DESCRIPTION

[0063] The oriented silicon steel and the method for manufacturing the same according to the present invention will be further explained and illustrated below in conjunction with specific embodiments. However, such explanation and illustration do not constitute an improper limitation on the technical solution of the present invention.

[0064] Examples 1-11 and Comparative Examples 1-14

[0065] (1) Smelting and casting to obtain slabs, the chemical composition contents of which are shown in Tables 1-1 and 1-2.

[0066] (2) Slab heating: Control the slab heating temperature to 900-1150°C.

[0067] (3) Hot rolling, which includes: rough rolling, coiling and heat preservation in a hot coil box, and finishing rolling; wherein the finishing temperature of rough rolling is higher than 960°C; the thickness of the intermediate billet after the rough rolling is 35-50 mm; the coiling temperature is 830-1060°C, and the coiling time is 30-200s; the starting temperature of finishing rolling is lower than 1050°C.

[0068] (4) Normalizing: The normalizing annealing temperature is 600-1000°C, and the normalizing annealing time is controlled to be 20-200s.

[0069] (5) Cold rolling: Control the cold rolling reduction ratio to >80%.

[0070] (6) Decarburization annealing: Control the decarburization annealing temperature to 800-900°C.

[0071] (7) Nitriding: Control the nitriding amount to 50-280ppm.

[0072] (8) Coating annealing isolation agent: MgO is used as the annealing isolation agent.

[0073] (9) High temperature annealing: The high temperature annealing temperature is controlled at 1100-1250°C and the annealing time is greater than 25h.

[0074] (10) Insulation coating and laser scoring: An insulation coating is applied to the sample after high temperature annealing, and laser scoring is performed to obtain oriented silicon steel with excellent magnetic properties.

[0075] The chemical element composition and related process design of the oriented silicon steel of Examples 1-11 of the present invention all meet the design specification requirements of the present invention; although Comparative Examples 1-14 are also manufactured using the above-mentioned process of steps (1) to (10), the component ratios of Comparative Examples 1-10 do not meet the requirements of the present invention, and the specific process parameters of Comparative Examples 11-14 do not meet the design requirements of the present invention.

[0076] Table 1-1 and Table 1-2 list the mass percentage ratios of the chemical elements of the grain-oriented silicon steels of Examples 1-11 and the comparative grain-oriented silicon steels of Comparative Examples 1-14.

[0077] Table 1-1. (wt%, the balance is Fe and unavoidable impurities)

[0078]

[0079]

[0080] Table 1-2. (wt%, the balance is Fe and unavoidable impurities)

[0081]

[0082]

[0083] Table 2-1 and Table 2-2 list the specific process parameters of the grain-oriented silicon steel of Example 1-11 and the comparative grain-oriented silicon steel of Comparative Example 1-14 in the above process steps.

[0084] Table 2-1.

[0085]

[0086] Table 2-2.

[0087]

[0088] In the above steps (3) and (4), the hot-rolled and normalized plates and strips of each embodiment and comparative example are observed and analyzed, and the average diameter d of the recrystallized grains in the surface layer (from the surface to 1 / 8 of the plate thickness) of the hot-rolled plate is detected. 1 And the average diameter d of recrystallized grains in the surface layer of the normalized plate (from the surface to 1 / 8 of the plate thickness) 2 The relevant test results are listed in the following Table 3.

[0089] Table 3.

[0090]

[0091]

[0092] It can be seen from Table 3 that the average diameter d of the recrystallized grains in the surface layer (from the surface to 1 / 8 of the plate thickness) of the hot-rolled plate of the oriented silicon steel of Examples 1-11 of the present invention is 1 The average diameter of recrystallized grains in the surface layer of the normalized plate (from the surface to 1 / 8 of the plate thickness) is greater than 40 μm. 2 All are greater than 120μm, and d 1 +d 2 All are less than 300μm.

[0093] However, the average diameters of the surface recrystallized grains of the hot-rolled plates and normalized plates of Comparative Examples 11-14 do not meet the requirements of the present invention.

[0094] The obtained oriented silicon steels of Examples 1-11 and Comparative oriented silicon steels of Comparative Examples 1-14 were sampled respectively, and the secondary recrystallization average diameter, finished product thickness, iron loss, magnetic induction and magnetostrictive vibration velocity sound pressure level LvA of the finished oriented silicon steels were tested, and the results are listed in the following Table 4. The relevant magnetic property test methods are as follows:

[0095] Magnetic property test: Test in accordance with the national standard GB / T 13789-2008 (magnetic property measurement method of single piece electrical steel strip).

[0096] Magnetostriction test: According to IEC technical report IEC / TP 62581, a non-contact laser Doppler vibrometer was used to measure the magnetostrictive vibration velocity sound pressure level LvA of the oriented silicon steels of Examples 1-11 and Comparative Examples 1-14 under the conditions of B=1.7T, f=2MPa (in the actual working conditions of the transformer, the compressive stress of the oriented silicon steel is 2-3MPa). In this article, LvA refers to the magnetostrictive vibration velocity sound pressure level of the oriented silicon steel under the above test conditions, and the unit is dB(A).

[0097] Table 4.

[0098]

[0099] It can be seen from Table 4 that the average diameter D of the secondary recrystallized grains of the finished products of the oriented silicon steel of Examples 1-11 of the present invention is less than 12 mm, and the magnetic induction B 800 All are greater than 1.95T, and the iron loss P 17 / 50 All are less than 0.74W / kg, and the magnetostriction LvA is less than 50dB, which has good magnetic properties and magnetostriction.

[0100] However, since the chemical element composition design or hot rolling and normalizing processes of Comparative Examples 1-14 do not meet the requirements of the present invention, their magnetic properties and LvA performance are relatively poor.

[0101] It should be noted that the combination of the various technical features in this case is not limited to the combination described in the claims of this case or the combination described in the specific embodiments. All technical features recorded in this case can be freely combined or combined in any way unless there is a contradiction between them.

[0102] It should also be noted that the above-listed embodiments are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made therewith can be directly derived or easily associated with by those skilled in the art from the contents disclosed in the present invention, and all should belong to the protection scope of the present invention.

Claims

1. A oriented silicon steel containing Fe and inevitable impurity elements, It is characterized in that It also contains the following chemical elements in the following mass percentages: C: 0.02~0.08%, Si: 2.0~4.5%, Mn: 0.02~0.30%, 0<S≤0.0050%, Als: 0.01~0.04%, N: 0.002~0.01%, Nb: 0.005~0.08%; Sb: 0.01~0.30%; Cr：0.01～0.30％； Bi: 0.01~0.60%; And P: 0.01~0.1%, Sn: 0.01~0.30%, Cu: at least one of 0.01 to 0.50%.

2. The oriented silicon steel according to claim 1, It is characterized in that The mass percentage of each chemical element is: C: 0.02~0.08%, Si: 2.0~4.5%, Mn: 0.02~0.30%, 0<S≤0.0050%, Als: 0.01~0.04%, N: 0.002~0.01%, Nb: 0.005~0.08%; Sb: 0.01~0.30%; Cr：0.01～0.30％； Bi: 0.01~0.60%; And P: 0.01~0.1%, Sn: 0.01~0.30%, Cu: at least one of 0.01 to 0.50%; the remainder is Fe and other inevitable impurities.

3. The oriented silicon steel according to claim 1 or 2, It is characterized in that The average diameter D of the secondary recrystallized grains of the finished product is less than 12 mm.

4. The oriented silicon steel according to claim 1 or 2, It is characterized in that Its magnetic induction B 800 ≥1.95T, its iron loss P 17 / 50 ≤0.74W / kg, magnetostriction L v A≤50dB.

5. The oriented silicon steel according to claim 1 or 2, It is characterized in that Its thickness is 0.10~0.30mm.

6. The method for producing oriented silicon steel according to any one of claims 1 to 5, It is characterized in that Includes steps: (1) obtaining a slab; (2) Slab heating; (3) hot rolling, which includes: rough rolling, coiling and heat preservation in a hot coil box, and finishing rolling; in The rough rolling end temperature is higher than 960℃; the coiling temperature is 830~1060℃, and the coiling time is 30~200s; the finishing rolling start temperature is lower than 1050℃; (4) Normalizing annealing, the normalizing annealing temperature is 600-1000°C; (5) Cold rolling; (6) Decarburization annealing; (7) Nitriding; (8) Applying annealing isolation agent; (9) High temperature annealing; (10) Insulation coating and laser scoring.

7. The manufacturing method according to claim 6, It is characterized in that The average diameter d1 of the recrystallized grains on the surface of the hot-rolled plate obtained after step (3) is greater than 40 μm.

8. The manufacturing method according to claim 7, It is characterized in that The average diameter d2 of the recrystallized grains on the surface of the normalized plate obtained after step (4) is greater than 120 μm.

9. The manufacturing method according to claim 8, It is characterized in that The average diameter d1 of the recrystallized grains on the surface of the hot-rolled plate and the average diameter d2 of the recrystallized grains on the surface of the normalized plate satisfy: d1+d2<300μm.

10. The manufacturing method according to claim 6, It is characterized in that In step (2), the slab heating temperature is 900-1150°C.

11. The manufacturing method according to claim 6, It is characterized in that In step (4), the normalizing annealing time is controlled to be 20 to 200 seconds.

12. The manufacturing method according to claim 6, It is characterized in that In step (5), the cold rolling reduction ratio is controlled to be greater than 80%.

13. The manufacturing method according to claim 6, It is characterized in that In step (6), the decarburization annealing temperature is 800-900°C.

14. The manufacturing method according to claim 6, It is characterized in that In step (7), the nitriding amount is 50 to 280 ppm.

15. The manufacturing method according to claim 6, It is characterized in that In step (9), the high temperature annealing temperature is 1100-1250° C., and the annealing time is greater than 25 hours.

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