Normalizing-free copper-containing high-magnetic-induction oriented silicon steel and production method

Abstract

The invention discloses normalizing-free copper-containing high-magnetic-induction oriented silicon steel and a production method. The normalizing-free copper-containing high-magnetic-induction oriented silicon steel comprises the following components in percentage by weight: 0.015 to 0.043 percent of C, 2.74 to 4.31 percent of Si, 0.011 to 0.031 percent of Als, 0.045 to 0.097 percent of Mn, 0.31 to 0.59 percent of Cu, 0.05 to 0.15 percent of Sb, 0.0049 to 0.0103 percent of N and 0.005 to 0.017 percent of S. A relatively large amount of Cu element is added through steelmaking, and an enough innate inhibitor CuxS is obtained by adjusting a hot rolling process, so that the aim of omitting a normalizing process is fulfilled; the AlN inhibitor is obtained through the nitriding technology, a certain amount of sulfate or sulfide is added into the magnesium oxide separant, the sulfate or sulfide can permeate into a steel coil in the high-temperature annealing process to be combined with the Cu element to form a new CuxS inhibitor, and the inhibition capacity is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of high magnetic induction oriented silicon steel processing and manufacturing, and particularly relates to normalization-free copper-containing high magnetic induction oriented silicon steel and a production method. Background Art

[0002] High-induction oriented silicon steel is a soft magnetic material with excellent magnetic properties. Due to its high magnetic permeability and low loss characteristics, it is widely used in power transmission and transformation products such as large transformers to manufacture the iron cores within transformers. The key to improving the magnetic properties of oriented silicon steel lies in controlling the growth of grains with different orientations through the use of inhibitors, thereby forming a Goss texture with highly consistent orientation. The more accurate the Gauss texture orientation of the finished grains of oriented silicon steel, the higher the magnetic induction intensity and the lower the iron loss of the product. Therefore, inhibitors are crucial to improving the magnetic properties of high-induction oriented silicon steel. The existing production process for high-induction oriented silicon steel uses AlN as the main inhibitor. The hot-rolled sheet must be normalized at high temperatures to precipitate a large amount of fine AlN during the normalizing process and to homogenize the hot-rolled sheet structure. However, the normalizing process requires a complete set of equipment and facilities. At the same time, the additional process steps extend the production cycle, significantly increasing production costs.

[0003] Inhibitors are generally divided into innate and acquired inhibitors. Innate inhibitors are primarily added during the steelmaking process and are typically formed during hot rolling or normalizing. A sufficient amount and size of innate inhibitors can influence not only the size of primary recrystallized grains but also the secondary recrystallization during the high-temperature annealing stage. Acquired inhibitors are primarily added during nitriding or magnesium oxide and primarily affect secondary recrystallization. Normalizing is a key process for forming innate inhibitors. Precipitates such as AlN and MnS formed in hot-rolled steel are generally oversized, insufficiently inhibiting grain growth. Normalizing and solutionizing followed by precipitation are often required to obtain inhibitors of appropriate size. Omitting the normalizing step significantly reduces the number of inhibitory precipitates in the steel matrix, weakening the ability to inhibit primary recrystallization growth. This results in larger primary grains and a higher number of coarse grains during decarburization annealing. Non-uniform primary grains directly affect the occurrence and completeness of secondary recrystallization. Therefore, to avoid the normalizing step, it is necessary to precipitate inhibitors of appropriate size during hot rolling, while also completing the task of regulating the primary grain size during the normalizing step.

[0004] The current on-site production process primarily uses AlN as an inhibitor, requiring hot-rolled plates to be normalized at high temperatures. This process aims to precipitate a large amount of fine AlN, resulting in a more uniform microstructure and a greater number of recrystallized grains. However, this inevitably increases equipment and production costs. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides a normalization-free copper-containing high magnetic induction oriented silicon steel and a production method.

[0006] To achieve the above object, the present invention provides a normalization-free copper-containing high magnetic induction oriented silicon steel, wherein the high magnetic induction oriented silicon steel comprises, by weight percentage, the following components: C: 0.015-0.043%, Si: 2.74-4.31%, Als: 0.011-0.031%, Mn: 0.045-0.097%, Cu: 0.31-0.59%, Sb: 0.05-0.15%, N: 0.0049-0.0103%, S: 0.005-0.017%, and the remainder is Fe and unavoidable impurities.

[0007] The functions of each component in silicon steel are as follows: The main function of C is to maintain a certain amount of γ phase in the hot-rolled plate during high-temperature normalization, so that a large amount of fine AlN can be obtained during rapid cooling. This is mainly because the solid solubility in the γ phase is 10 times greater than that in the α phase. However, too much carbon will make decarburization difficult, affecting subsequent high-temperature annealing. In particular, since the normalization step is eliminated, decarburization is even more difficult, so the carbon content needs to be strictly controlled. When the C content is less than 0.015%, the proportion of the γ phase is insufficient. When the C content is greater than 0.043%, it is easy to cause the subsequent C content to exceed the standard, resulting in deterioration of magnetic properties. Therefore, the C content is set to 0.018% to 0.043%.

[0008] Si is an extremely effective element for increasing the resistance of oriented silicon steel and reducing eddy current losses. Increasing the silicon content can effectively reduce iron loss. However, Si tends to segregate at grain boundaries during the hot rolling phase transformation process, making it prone to cracking. When the silicon content is less than 2.74%, the iron loss reduction effect is not significant, and when the Si content exceeds 4.31%, the processing performance is reduced. Therefore, the Si content is set between 2.74% and 4.31%.

[0009] AlS is an important element in the formation of aluminum nitride inhibitors. When the AlS content is less than 0.011%, insufficient aluminum nitride is precipitated after normalization, resulting in insufficient inhibitor strength. On the other hand, when the AlS content exceeds 0.031%, the AlN becomes coarser, reducing inhibitor strength. Therefore, the AlS content is set between 0.011% and 0.031%.

[0010] Mn reacts with S to form MnS, making it an important supplementary inhibitor in grain-oriented silicon steel. It inhibits grain growth during the primary recrystallization process. Mn also prevents cracks during hot rolling. When the manganese content is less than 0.045%, its full effect is not achieved. On the other hand, when the manganese content exceeds 0.097%, the magnetic flux density of the grain-oriented silicon steel decreases. Therefore, the manganese content is set between 0.045% and 0.097%.

[0011] Cu can expand the γ phase area, which is beneficial to increase the Si content, reduce the carbon content and increase the acid-soluble aluminum of HiB steel. x S precipitation phase improves the inhibition ability, especially the inhibition ability in the high temperature section of high temperature annealing. Generally, the Cu content is 0.31%-0.59%. The S content is set to 0.05% to 0.017%. If the S content is too low, it is not enough to form sufficient Cu x S inhibitor, too high S content can easily lead to MnS and Cu x Coarsening of S.

[0012] Sb can segregate at the grain boundary, reduce the grain boundary energy, and enhance the inhibition of primary grain growth. At the same time, it can also significantly delay the growth of Cu x The coarsening rate of S at high temperature. The Sb content is set to 0.05% to 0.15%.

[0013] Nitrogen is an important element in the formation of aluminum nitride. AlN in grain-oriented silicon steel is generally formed through subsequent nitriding. The nitrogen content range is set to 0.049-0.0103%.

[0014] Furthermore, the weight percentages of Als, Cu, and S satisfy formula (1) and formula (2): 11≤75×[Als] + 32×[Cu]≤19(1) 15≤([Cu] / 64.5]) / ([S] / 32)≤40 (2) Among them, [Als] is the numerical portion of the weight percentage of Als, [Cu] is the numerical portion of the weight percentage of Cu, and [S] is the numerical portion of the weight percentage of S, that is, the numerical portion of the weight percentage without the percentage sign, and the following are all numerical portions.

[0015] A method for producing the normalization-free copper-containing high magnetic induction oriented silicon steel as described above is also provided. The process flow of the production method is: steelmaking and continuous casting → hot rolling → pickling and cold rolling → decarburization and nitriding continuous annealing → coating of magnesium oxide isolation agent → high temperature annealing → stretching and leveling annealing → coating of insulating coating → finishing.

[0016] The raw material slab is heated to a temperature T0 by hot rolling, wherein the soaking temperature T0 of the hot rolling satisfies the formula (3), and the hot rolling is kept at the temperature T0 for 147-248 minutes; 935-3320×([Als]-1.929×[N])+425×[Cu]+42×H ≤T0≤975-3320×([Als]-1.929×[N])+425×[Cu]+42×H (3) Wherein, [Als], [N] and [Cu] are the numerical parts of the weight percentages of the steelmaking components Als, N and Cu respectively; H is the thickness of the hot-rolled coil in mm.

[0017] If the hot rolling soaking temperature is too low, it cannot ensure the full dissolution of inhibitors such as AlN, while if the temperature is too high, it will cause excessive growth of austenite grains.

[0018] After the soaked slab is rolled for 6-7 times, the rolled hot coil has a thickness H of 1.95-3.02 mm. The main difference between the present invention and the conventional hot rolling process is that after the finishing rolling, a period of holding and coiling temperature control is required.

[0019] After finishing rolling, the coil temperature is lowered to T1, which is 698-823°C, and held at T1 for 14-39 seconds. This is mainly because after finishing rolling, the coil structure is mainly deformation structure, and a period of holding is conducive to the recovery of deformation structure.

[0020] The control of coiling temperature is mainly due to Cu x Inhibitors such as S and AlN are prone to aggregation and coarsening. Low-temperature coiling can effectively inhibit the formation of coarse inhibitors during the slow cooling process after coiling. Therefore, the coiling temperature T2 satisfies formula (4): 532-203×[Als] - 255×[Cu]+50×H≤T2≤552-203×[Als] - 255×[Cu]+50×H (4).

[0021] Furthermore, in the pickling and cold rolling process, the hot-rolled coil is directly pickled and then cold-rolled to the finished thickness through one-time reduction, and the cold rolling reduction rate is 81.25-92.36%.

[0022] Furthermore, the cold rolled coil is subjected to decarburization and nitriding continuous annealing process to further obtain a stable Cu x S and AlN inhibitors, the cold rolled coil is subjected to three-stage decarburization annealing. The first stage annealing temperature is 774-817℃ and the annealing time is 24-45s. This stage is mainly for decarburization, Cu x Further precipitation of S and preliminary primary recrystallization; the second stage annealing temperature is 827-866℃ and the annealing time is 56-89s. This stage is mainly to promote the formation of surface oxide layer; the third stage is nitriding treatment with a temperature of 810-850℃ and a time of 11-23s, and the nitriding amount is controlled at 100-150ppm.

[0023] Furthermore, in the step of coating the magnesium oxide release agent, water is added to the magnesium oxide release agent mixing tank and sulfate or sulfide accounting for 3-13% of the total weight of the magnesium oxide is added, and then titanium dioxide is added to the magnesium oxide release agent, stirred until uniform, MgO is added, stirring is continued for 1-2 hours, and the steel plate is coated and dried; and the titanium dioxide content accounts for 2-15% of the total weight of the magnesium oxide.

[0024] Furthermore, in the high-temperature annealing process, the temperature is rapidly increased in the heating stage I at a rate of 51-72°C / h; the holding stage I is set at a low temperature of 612-735°C for 10-21 hours; the temperature is increased to 850-950°C at a medium rate of 11-33°C / h in the heating stage II; the temperature is held at 850-950°C for 12-31 hours in the holding stage II; the temperature is increased to 1150-1250°C at a rate of 8-15°C / h in the heating stage III, and then enters the holding stage III, followed by a 45-98 hour heat preservation and purification. Among them, N2 atmosphere is used before the end of insulation section II, 48-78% H2 is used after the end of insulation section II, and the rest is N2. Pure atmosphere is used after entering insulation section III.

[0025] Inhibitors are generally divided into innate inhibitors and acquired inhibitors. Innate inhibitors are mainly added during the steelmaking process and are generally formed during hot rolling or normalizing. Innate inhibitors of sufficient quantity and size can not only affect the size of the primary recrystallized grains, but also the secondary recrystallization during the high-temperature annealing stage. Acquired inhibitors are mainly added during nitriding or magnesium oxide and mainly affect the size of the secondary recrystallized grains. Generally speaking, the size of precipitates such as AlN and MnS formed in hot-rolled plates is relatively large, and their ability to inhibit grain growth is insufficient. It is often necessary to undergo normalizing solid solution followed by precipitation to obtain inhibitors of the right size. If the normalizing step is omitted, the number of precipitates with inhibitory ability in the steel matrix will be greatly reduced.

[0026] In order to avoid normalization and improve the effect of effective inhibitors in hot-rolled plates, the present invention also adds more Cu elements during the steelmaking process. Cu can combine with S to generate more Cu x S and other innate inhibitors, when the temperature is T0 (i.e., satisfying formula (3)), Cu is dissolved in the matrix. At 750-900 ° C, Cu usually precipitates as nano-scale ε-Cu particles, with a size of generally 5-20nm, which can act as an inhibitor. At the same time, Cu can also precipitate together with second-phase particles such as MnS and AlN to form a composite precipitate phase (Cu, Mn) S, which can also play an inhibitory role. Therefore, by controlling the adjustment of the hot rolling process, the ε-Cu and Cu can be controlled. x The purpose of precipitation density and size of S, etc.

[0027] At the same time Cux S can not only be obtained through the optimization of hot rolling process, thus forming an innate inhibitor and effectively regulating the primary grain size. Cu element can also form Cu together with S during high temperature annealing. x S, supplements the deficiency of innate inhibitors, forms acquired inhibitors, and plays a role in the high-temperature annealing process.

[0028] To ensure effective precipitation of CuS during hot rolling, the soaking temperature must be strictly controlled. Excessively low hot rolling temperatures prevent the full dissolution of inhibitors such as CuS and AlN. Insufficient dissolution can lead to coarse and unevenly distributed precipitates, weakening the inhibitory effect. Excessively high temperatures, on the other hand, can lead to excessive austenite grain growth, directly impacting microstructure uniformity. After finishing rolling, the temperature is lowered to 698-823°C for a period of holding, primarily to restore the hot-rolled microstructure.

[0029] The coiling temperature T2 must be controlled during the hot rolling process (i.e., satisfying formula (4)). Low-temperature coiling can effectively inhibit the formation of coarse Cu during the slow cooling process after coiling. x The formation of S and AlN.

[0030] In order to increase Cu x In order to improve the inhibitory ability of S in high-temperature annealing, the present invention also adds a certain amount of sulfate or sulfide to the magnesium oxide separator, which can penetrate into the steel coil during high-temperature annealing and combine with Cu element to form a new CuS inhibitor, further improving the inhibitory ability.

[0031] At the initial stage of high temperature heating (850-950℃), Cu x S plays a major inhibitory role, and AlN may not have fully exerted its maximum pinning force at this stage. In the middle and late stages of heating (950-1050℃), as Cu x As sulfur begins to coarsen and dissolve, the inhibitory effect of AlN gradually strengthens and becomes dominant, relaying the inhibition of grain boundary migration and ensuring smooth secondary recrystallization of Goss grains. This relay inhibition mechanism covers a wider temperature range than a single AlN inhibition mechanism, effectively ensuring the time window for secondary recrystallization, maintaining a stable inhibition effect, and achieving more complete secondary recrystallization.

[0032] To fully maximize the effectiveness of the CuS inhibitor, the atmosphere must be free of H2 before the CuS decomposition fails. This is because S and H2 react to form H2S (gas), which escapes and accelerates the decomposition of CuS. Therefore, during the high-temperature annealing process, the atmosphere in the annular furnace remains pure nitrogen until the CuS decomposition fails (before the end of the second holding period).

[0033] Compared with the prior art, the present invention has the following advantages: the present invention adds relatively more Cu element by steelmaking, and obtains sufficient innate inhibitor Cu by adjusting the hot rolling process. x S, thereby achieving the purpose of eliminating the normalization process; in order to increase Cu x The inhibitory ability of S in high temperature annealing is obtained by nitriding process, and a certain amount of sulfate or sulfide is added to the magnesium oxide separator, which can penetrate into the steel coil during high temperature annealing and combine with Cu element to form new Cu x S inhibitor further improves the inhibition ability, and ultimately achieves the goal of avoiding normalization while improving magnetic properties. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to specific embodiments.

[0035] Table 1 is a list of chemical compositions of various embodiments and comparative examples of the present invention; Table 2 is a list of main process parameters of various embodiments and comparative examples of the present invention; Table 3 is a list of magnetic properties of products of various embodiments of the present invention and comparative examples.

[0036] The production process of grain-oriented silicon steel includes the following steps: steelmaking and continuous casting → hot rolling → pickling and cold rolling → decarburization and nitriding continuous annealing → coating with magnesium oxide separator → high temperature annealing → stretching and leveling annealing → coating with insulating coating → finishing. The measures to achieve the above objectives are as follows: (1) The components of high magnetic induction oriented silicon steel include by weight percentage: C: 0.015-0.043%, Si: 2.74-4.31%, Als: 0.011-0.031%, Mn: 0.045-0.097%, Cu: 0.31-0.59%, Sb: 0.05-0.15%, N: 0.0049-0.0103%, S: 0.005-0.017%, and the rest is Fe and unavoidable impurities.

[0037] The weight percentage contents of Als, Cu, and S satisfy formula (1) and formula (2): 11≤75×[Als] + 32×[Cu]≤19(1) 15≤([Cu] / 64.5]) / ([S] / 32)≤40 (2) Here, [Als] is the numerical portion of the weight percentage of Als, [Cu] is the numerical portion of the weight percentage of Cu, and [S] is the numerical portion of the weight percentage of S. That is, the numerical portion of the weight percentage is not followed by a percentage sign, and the following are all numerical portions.

[0038] (2) The raw material slab is hot rolled to heat the hot rolled plate to a temperature T0, wherein the soaking temperature T0 of the hot rolling satisfies the formula (3), and the hot rolled plate is kept at the temperature T0 for 147-248 minutes; 935-3320×([Als]-1.929×[N])+425×[Cu]+42×H ≤T0≤975-3320×([Als]-1.929×[N])+425×[Cu]+42×H (3) Wherein, [Als], [N] and [Cu] are the numerical parts of the weight percentages of the steelmaking components Als, N and Cu respectively; H is the thickness of the hot-rolled coil in mm.

[0039] After the soaked slab is rolled for 6-7 times, the rolled hot coil has a thickness H of 1.95-3.02 mm. The main difference between the present invention and the conventional hot rolling process is that after the finishing rolling, a period of holding and coiling temperature control is required.

[0040] After finishing rolling is completed, the temperature of the steel coil is lowered to T1, which is 698-823℃, and is kept at T1 for 14-39s.

[0041] After the insulation is completed, the coiling temperature must be strictly controlled. The coiling temperature T2 satisfies the formula (4): 532-203×[Als] - 255×[Cu]+50×H≤T2≤552-203×[Als] - 255×[Cu]+50×H (4).

[0042] (3) The hot-rolled coil is directly pickled and then cold-rolled to the finished thickness with a cold-rolling reduction rate of 81.25-92.36%.

[0043] (4) The cold rolled coil is subjected to decarburization and nitriding continuous annealing process to further obtain stable Cu x S and AlN inhibitors, the cold rolled coil is subjected to three-stage decarburization annealing. The first stage annealing temperature is 774-817℃ and the annealing time is 24-45s. This stage is mainly for decarburization, Cu x Further precipitation of S and preliminary primary recrystallization; the second stage annealing temperature is 827-866℃ and the annealing time is 56-89s. This stage is mainly to promote the formation of surface oxide layer; the third stage is nitriding treatment with a temperature of 810-850℃ and a time of 11-23s, and the nitriding amount is controlled at 100-150ppm.

[0044] (5) The process of coating the magnesium oxide separator is to add water and sulfate or sulfide accounting for 3-13% of the total weight of the magnesium oxide to the magnesium oxide separator mixing tank, and then add titanium dioxide to the magnesium oxide separator, stir until uniform, add MgO, continue stirring for 1-2 hours, coat on the steel plate and dry; and the titanium dioxide content accounts for 2-15% of the total weight of the magnesium oxide.

[0045] (6) High temperature annealing process, heating stage I adopts rapid heating, heating rate is 51-72℃ / h; holding stage I is set to 612-735℃ low temperature for 10-21h; heating stage II adopts medium speed heating to 850-950℃, heating rate is 11-33℃ / h; holding stage II is set to 850-950℃, holding for 12-31h; heating stage III is heated to 1150-1250℃ at 8-15℃ / h and enters holding stage III, followed by holding and purification for 45-98h; Among them, N2 atmosphere is used before the end of insulation section II, 48-78% H2 is used after the end of insulation section II, and the rest is N2. Pure atmosphere is used after entering insulation section III.

[0046] (7) Stretching, flattening, annealing, and applying insulating coating.

[0047] Table 1. List of ingredients of various embodiments of the present invention and comparative examples (wt%) Table 2 Main process control list of each embodiment of the present invention and comparative example Table 3 Material parameters and product magnetic properties of various embodiments of the present invention and comparative examples It can be seen from Table 3 that the low temperature and high magnetic induction oriented silicon steel products produced by the embodiment of the method of the present invention are the same as those produced by the embodiment process under the same specification conditions. 800 The average value reaches above 1.895T, basically reaching the level of HiB steel, which is higher than the comparative products with the same specifications and thickness, and the iron loss is also better than the comparative products.

[0048] This specific implementation is only the best example and is not a restrictive implementation of the technical solution of the present invention.

Claims

1. A copper-containing high magnetic induction oriented silicon steel that does not require normalization, characterized by: The components of high magnetic induction oriented silicon steel include, by weight percentage: C: 0.015-0.043%, Si: 2.74-4.31%, Als: 0.011-0.031%, Mn: 0.045-0.097%, Cu: 0.31-0.59%, Sb: 0.05-0.15%, N: 0.0049-0.0103%, S: 0.005-0.017%, and the rest are Fe and unavoidable impurities.

2. The normalization-free copper-containing high magnetic induction oriented silicon steel according to claim 1, characterized in that: The weight percentages of Als, Cu, and S satisfy formula (1) and formula (2): 11≤75×[Als] + 32×[Cu]≤19(1) 15≤([Cu] / 64.5]) / ([S] / 32)≤40 (2) Here, [Als] is the numerical portion of the weight percentage of Als, [Cu] is the numerical portion of the weight percentage of Cu, and [S] is the numerical portion of the weight percentage of S.

3. A method for producing normalization-free copper-containing high magnetic induction oriented silicon steel as claimed in claim 1, characterized in that: The process flow of the production method is: steelmaking and continuous casting → hot rolling → pickling and cold rolling → decarburization and nitriding continuous annealing → coating of magnesium oxide isolation agent → high temperature annealing → stretching and leveling annealing → coating of insulation coating → finishing; The hot rolling soaking temperature T0 satisfies formula (3), and the temperature is kept at T0 for 147-248 minutes; 935-3320×([Als]-1.929×[N])+425×[Cu]+42×H ≤T0≤975-3320×([Als]-1.929×[N])+425×[Cu]+42×H (3) Wherein, [Als], [N] and [Cu] are the numerical parts of the weight percentages of the steelmaking components Als, N and Cu respectively; H is the thickness of the hot-rolled coil in mm.

4. The method for producing normalization-free copper-containing high magnetic induction oriented silicon steel according to claim 3, characterized in that: The coiling temperature T2 of the hot rolling process satisfies formula (4): 532-203×[Als] - 255×[Cu]+50×H≤T2≤552-203×[Als] - 255×[Cu]+50×H (4).

5. The method for producing normalization-free copper-containing high magnetic induction oriented silicon steel according to claim 3, characterized in that: After the finishing rolling of the hot rolling process is completed, the temperature of the steel coil is lowered to T1, which is 698-823° C., and is kept at T1 for 14-39 seconds.

6. The method for producing normalization-free copper-containing high magnetic induction oriented silicon steel according to claim 3, characterized in that: The slab after being soaked is rolled through 6-7 passes, and the thickness H of the rolled hot coil is 1.95-3.02 mm.

7. The method for producing normalization-free copper-containing high magnetic induction oriented silicon steel according to claim 3, characterized in that: In the pickling and cold rolling process, the hot-rolled coil is directly pickled and then cold-rolled once to the finished thickness, and the cold rolling reduction rate is 81.25-92.36%.

8. The method for producing normalization-free copper-containing high magnetic induction oriented silicon steel according to claim 3, characterized in that: In the decarburization and nitriding continuous annealing process, the cold-rolled coil undergoes three-stage decarburization annealing, wherein the temperature of the first stage is 774-817°C and the annealing time is 24-45s, the temperature of the second stage is 827-866°C and the annealing time is 56-89s, and the third stage is nitriding treatment, the temperature is 810-850°C and the time is 11-23s, and the nitriding amount is controlled at 100-150ppm.

9. The method for producing normalization-free copper-containing high magnetic induction oriented silicon steel according to claim 3, characterized in that: The magnesium oxide release agent coating step comprises adding water and sulfate or sulfide accounting for 3-13% of the total weight of the magnesium oxide to a magnesium oxide release agent mixing tank, then adding titanium dioxide to the magnesium oxide release agent, stirring until uniform, adding MgO, continuing stirring for 1-2 hours, coating on a steel plate, and drying; and the titanium dioxide content accounts for 2-15% of the total weight of the magnesium oxide.

10. The method for producing normalization-free copper-containing high magnetic induction oriented silicon steel according to claim 3, characterized in that: In the high-temperature annealing process, the temperature is rapidly increased in heating stage I at a rate of 51-72°C / h; the temperature is kept at a low temperature of 612-735°C for 10-21 hours in holding stage I; the temperature is increased to 850-950°C at a medium rate of 11-33°C / h in heating stage II; the temperature is kept at 850-950°C for 12-31 hours in holding stage II; the temperature is increased to 1150-1250°C at a rate of 8-15°C / h in heating stage III, and then kept in holding stage III for 45-98 hours for purification; Among them, N2 atmosphere is used before the end of insulation section II, 48-78% H2 is used after the end of insulation section II, and the rest is N2. Pure atmosphere is used after entering insulation section III.

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