Cu-containing oriented silicon steel and preparation method thereof

Abstract

The invention provides Cu-containing oriented silicon steel and a preparation method thereof, and belongs to the technical field of oriented silicon steel preparation. The method comprises the following steps that raw materials are smelted to obtain a Cu-containing oriented silicon steel casting blank, then the casting blank is sequentially subjected to hot rolling, normalizing treatment, cold rolling, decarburization annealing treatment and gradient temperature annealing treatment, and the Cu-containing oriented silicon steel is obtained. Wherein the casting blank is prepared from the following components in percentage by weight: 0.03 to 0.06 percent of C, 2.8 to 3.0 percent of Si, 1.0 to 1.3 percent of Cu and the balance of Fe and inevitable impurities. By adopting the method, the step of heating and purifying the steel plate at high temperature for a long time in the prior art is omitted, the energy consumption is greatly reduced, and the production efficiency is improved. The magnetic property B8 of the prepared Cu-containing oriented silicon steel ranges from 1.76 T to 1.82 T, and the iron loss P17 / 50 ranges from 1.40 W / kg to 1.35 W / kg.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy materials, and in particular to the technical field of oriented silicon steel preparation, and specifically to a Cu-containing oriented silicon steel and a preparation method thereof. Background Art

[0002] When preparing oriented silicon steel, it is necessary to introduce dispersed second phase particles as inhibitors to inhibit the growth of primary recrystallized grains and promote the abnormal growth of Goss-oriented grains in secondary recrystallization, ultimately forming a single Goss orientation.

[0003] Chinese patent application publication CN116463545A discloses a copper-containing low-temperature oriented silicon steel and a manufacturing method thereof, wherein the Cu content satisfies: 3%≤Si+Cu≤4.4%, 0.05≤Cu / Si≤0.13, 24≤(Mn+Cu) / S≤118. The method is carried out through the steps of smelting and casting, hot rolling, two-stage normalizing annealing, cold rolling, decarburization annealing, nitriding, coating of high-temperature isolation agent, high-temperature annealing, coating of insulating coating and hot stretching and flattening annealing, to prepare oriented silicon steel with good magnetic properties, and its iron loss P 17 / 50 <0.85W / Kg, magnetic induction B8>1.90T. However, since AlN and (Cu, Mn)S are used as inhibitors in this method, a long purification annealing at 1200°C is required during the high temperature annealing process. At the same time, this method adopts two-stage normalization, and nitriding treatment is required in the subsequent process. The long purification annealing and additional nitriding treatment process will reduce production efficiency.

[0004] Patent application publication CN110055393A discloses a method for producing thin-gauge, low-temperature, high-magnetic-induction oriented silicon steel strips, including the following steps: heating, hot rolling, normalizing, cold rolling, decarburization, nitriding, conventional coating of isolating agent, high-temperature annealing, flattening and stretching annealing, and coating of insulating layer. The inhibitor used in this method is AlN, which also requires nitriding treatment and high-temperature and long-term (1100~1300℃ insulation for 15~30h) purification treatment, which affects production efficiency.

[0005] Patent application announcement CN101275201B discloses a oriented electrical steel and a manufacturing method thereof, wherein the chemical composition of the oriented electrical steel is as follows: C 0.01-0.04%, Si 1.0-1.8%, Mn 0.15-0.20%, S≤0.005%, P≤0.02%, Al≤0.006%, N≤0.006%, Cu 0.8-1.2%, Ti≤0.005%, and the rest are inevitable impurities and Fe. The method for manufacturing the oriented electrical steel is as follows: smelting and casting into billets; hot rolling, the billets are heated in the furnace at a temperature of 1000-1200°C; cold rolling; intermediate annealing; secondary recrystallization annealing, continuous secondary recrystallization annealing is performed on the steel plates rolled to the finished thickness, the annealing temperature is 800-900°C, and the annealing time is 40-60min; insulation coating and drying. Although a large amount of ε-Cu phase is precipitated in this scheme, which can act as an inhibitor, Cu and S also precipitate (Cu, Mn) x S or Cu x S, long-term high-temperature annealing treatment is still required to purify the steel plate, and the process control during continuous annealing is relatively strict.

[0006] Patent application announcement text CN101545072B discloses a production method of high electromagnetic performance oriented silicon steel, including steelmaking in a converter or electric furnace, obtaining a slab after secondary refining and continuous casting of molten steel, followed by hot rolling, first cold rolling, decarburization annealing, second cold rolling, coating an annealing separator with MgO as the main component, and then high temperature annealing, and finally coating an insulating coating and stretching and flattening annealing. The components of the slab (by weight percentage) are: C: 0.020% to 0.050%, Si: 2.6% to 3.6%, S: 0.015% to 0.025%, AlS: 0.008% to 0.028%, N: 0.005% to 0.020%, Mn: 0.15% to 0.5%, and 10≤Mn / S≤20, Cu: 0.3% to 1.2%, and Cu / Mn≥2, and the rest are Fe and unavoidable impurities. This method also cannot avoid the need to purify the steel plate during the high-temperature annealing process. Summary of the invention

[0007] Based on the above technical problems, the present invention provides a Cu-containing oriented silicon steel and a preparation method thereof. By optimizing the composition of the steel plate ingot, using a single Cu element as an inhibitor, without the need for purification of the steel plate, and using gradient temperature annealing for secondary recrystallization, a single Goss-oriented silicon steel with excellent magnetic properties is obtained.

[0008] In order to achieve the above object, the present invention specifically adopts the following technical solutions: A method for preparing Cu-containing oriented silicon steel comprises the following steps: S1. Smelting the raw materials to obtain Cu-containing oriented silicon steel ingot; the composition of the ingot is as follows, in terms of mass percentage: 0.03% to 0.06% C, 2.8% to 3.0% Si, 1.0% to 1.3% Cu, and the balance is Fe and unavoidable impurities; S2, hot rolling the ingot to obtain a hot-rolled plate; S3, performing normalizing treatment on the hot-rolled plate to obtain a normalized plate; S4, cold rolling the normalized sheet to obtain a cold rolled sheet; S5, performing decarburization annealing treatment on the cold-rolled sheet; S6. After the treatment in step S5 is completed, a gradient temperature annealing treatment is performed, firstly the temperature is raised to the first temperature for insulation, and then the temperature is raised to the second temperature for insulation after the insulation is completed; then the temperature is raised to the third temperature; finally, the temperature is directly air-cooled or cooled to the fourth temperature and then air-cooled to obtain a oriented silicon steel product.

[0009] In a preferred embodiment, the casting temperature during smelting in step S1 is 1500°C to 1550°C.

[0010] In a preferred embodiment, the hot rolling temperature in step S2 is 1150-1180° C.; the thickness of the hot rolled plate is 2.0-2.3 mm.

[0011] In a preferred embodiment, the temperature of the normalization treatment in step S3 is 850-950° C., the insulation time is 2-10 min, and the product is quenched into boiling water after the insulation is completed.

[0012] In a preferred embodiment, the cold rolling reduction rate in step S4 is 87%; the sheet is preheated at 250-300° C. for 5-10 minutes before cold rolling; and the thickness of the cold rolled sheet is 0.25-0.3 mm.

[0013] In a preferred embodiment, the temperature of the decarburization annealing treatment in step S5 is 835-850° C., and the holding time is 6-8 min.

[0014] In a preferred embodiment, the atmosphere composition of the decarburization annealing treatment in step S5 is, by volume percentage, 20% to 25% H2, 65% to 70% N2, and the remainder is water vapor.

[0015] In a preferred embodiment, in step S6, the first temperature is 500-550°C, the second temperature is 890-900°C, the third temperature is 1100-1200°C, and the fourth temperature is 900-950°C.

[0016] In a preferred embodiment, the heating rate to the first temperature is 80~85°C / h, and the holding time is 2~5h; the heating rate to the second temperature is 20~90°C / h, and the holding time is 10~15h; the heating rate to the third temperature is 15~45°C / h; the cooling rate to the fourth temperature is 50~55°C / h.

[0017] The present invention also provides a Cu-containing oriented silicon steel prepared by the preparation method in any of the above schemes. The magnetic property B8 of the Cu-containing oriented silicon steel is 1.76-1.82T, and the iron loss P 17 / 50 It is 1.40~1.35W / kg.

[0018] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: (1) In the present invention, the composition of Cu-containing oriented silicon steel is optimized, and a single nano Cu particle is used as an inhibitor, which has a simple composition and is easy to smelt. At the same time, since Cu is used as a single inhibitor-forming element, there is no need to purify the steel plate in the later stage of high-temperature annealing, and the atmosphere control requirements during high-temperature annealing are not strict. The control process is simple, which greatly reduces the energy consumption in the production process and improves production efficiency.

[0019] (2) In the present invention, a gradient temperature annealing process is adopted after decarburization annealing. The precipitation of Cu particles is first promoted by low-temperature aging treatment. The fine and dispersed nano Cu particles can effectively inhibit the growth of primary recrystallization grains in the early stage of high-temperature annealing. As the temperature rises, the Cu particles gradually coarsen and dissolve back, the inhibition ability weakens, and the Goss grains begin to grow. After the secondary recrystallization begins, they gradually swallow up the matrix grains to form a single Goss orientation.

[0020] (3) After the secondary recrystallization is completed, a faster cooling rate can inhibit the precipitation of inhibitor particles (Cu particles) and reduce their impact on the magnetic properties of the finished steel plate.

[0021] (4) The preparation method of the present invention is energy-saving and efficient, and the magnetic properties of the prepared oriented silicon steel meet the requirements of national standards. DETAILED DESCRIPTION

[0022] The following content is combined with the embodiments to clearly and completely describe the technical solution of the present application so that those skilled in the art can fully understand the present application. Obviously, the described embodiments are only some preferred embodiments of the present application, rather than all embodiments. Any equivalent transformation or substitution made to the following implementation modes by those of ordinary skill in the art without creative work belongs to the protection scope of the present application.

[0023] In the following examples, unless otherwise specified, all percentages are by mass. The magnetic properties and iron loss performance testing methods of oriented silicon steel refer to the methods in GB / T 13789-2022 "Method for measuring magnetic properties of electrical steel strip (sheet) using a single-piece tester".

[0024] A specific embodiment of the present invention provides a method for preparing Cu-containing oriented silicon steel, comprising the following steps: S1. Smelting and casting are carried out according to the following chemical composition: 0.03%~0.06% C, 2.8%~3.0% Si, 1.0~1.3% Cu, and the balance is Fe and inevitable impurities; the casting temperature is 1500~1550℃ to obtain Cu-containing oriented silicon steel ingot.

[0025] S2. Hot rolling the ingot obtained in step S1 at 1150°C-1180°C to a thickness of 2.0-2.3 mm.

[0026] S3, placing the hot-rolled plate obtained in step S2 at 850-950°C for normalization treatment, with a holding time of 2-10 minutes, and quenching into boiling water after the holding is completed.

[0027] S4, cold rolling the normalized plate obtained after normalizing in step S3, with a cold rolling reduction rate of 87%, and cold rolling the plate to 0.25-0.3 mm through multiple passes, and preheating at 250-300° C. for 5-10 min before cold rolling.

[0028] S5. The cold rolled sheet obtained in step S4 is subjected to decarburization annealing at 835-850°C for 6-8 minutes. The decarburization annealing atmosphere is composed of 20%-25% H2, 65%-70% N2, and the remainder is water vapor, in terms of volume percentage.

[0029] S6. After the decarburization annealing treatment in step S5 is completed, high temperature annealing treatment is performed. The high temperature annealing conditions are: heating to 500-550°C at a rate of 80-85°C / h, keeping warm for 2-5h for aging treatment; then heating to 890-900°C at a heating rate of 20-90°C / h, keeping warm for 10-15h; heating to 1100-1200°C at a heating rate of 15-45°C / h. Air cooling; or cooling to 900-950°C at a rate of 50-55°C / h, taking out of the furnace, and air cooling.

[0030] Example 1 A method for preparing Cu-containing oriented silicon steel comprises the following steps: S1. The raw materials are smelted at a casting temperature of 1500°C to obtain Cu-containing oriented silicon steel ingots; the composition of the ingots is as follows: 0.03% C, 2.8% Si, 1.0% Cu, and the remainder is Fe and unavoidable impurities.

[0031] S2. Hot-roll the ingot obtained in step S1 at 1150°C to a thickness of 2.0 mm.

[0032] S3, placing the hot-rolled plate obtained in step S2 at 850°C for normalization treatment, the heat preservation time is 2 minutes, and quenching into boiling water after the heat preservation is completed.

[0033] S4, cold rolling the normalized plate obtained after normalizing in step S3, with a cold rolling reduction rate of 87%, and cold rolling to 0.25 mm through multiple passes, and preheating at 250° C. for 5 minutes before cold rolling.

[0034] S5. The cold rolled sheet obtained in step S4 is subjected to decarburization annealing at 835° C. for 6 minutes. The decarburization annealing atmosphere comprises, by volume percentage, 20% H2, 65% N2 and 15% water vapor.

[0035] S6. After the decarburization annealing treatment in step S5 is completed, high temperature annealing treatment is performed. The high temperature annealing conditions are: heating to 500°C at a rate of 80°C / h, keeping the temperature for 2h for aging treatment; then heating to 890°C at a heating rate of 20°C / h, keeping the temperature for 10h; heating to 1100°C at a heating rate of 15°C / h. Air cooling, or cooling to 900°C at a rate of 50°C / h, taking out of the furnace, and air cooling.

[0036] The prepared oriented silicon steel product was tested and its magnetic property B8 was 1.76T and iron loss P 17 / 50 It is 1.40W / kg.

[0037] Example 2 A method for preparing Cu-containing oriented silicon steel comprises the following steps: S1. The raw materials are smelted at a casting temperature of 1525°C to obtain Cu-containing oriented silicon steel ingots; the composition of the ingots is as follows: 0.05% C, 2.9% Si, 1.2% Cu, and the remainder is Fe and unavoidable impurities.

[0038] S2. Hot-roll the ingot obtained in step S1 at 1160°C to a thickness of 2.1 mm.

[0039] S3, placing the hot-rolled plate obtained in step S2 at 900°C for normalization treatment, the heat preservation time is 5 minutes, and quenching into boiling water after the heat preservation is completed.

[0040] S4, cold rolling the normalized plate obtained after normalizing in step S3, with a cold rolling reduction rate of 87%, and cold rolling to 0.27 mm through multiple passes, and preheating at 280° C. for 8 min before cold rolling.

[0041] S5. The cold rolled sheet obtained in step S4 is subjected to decarburization annealing at 840°C for 7 minutes. The decarburization annealing atmosphere comprises, by volume percentage, 23% H2, 66% N2 and 11% water vapor.

[0042] S6. After the decarburization annealing treatment in step S5 is completed, high temperature annealing treatment is performed. The high temperature annealing conditions are: heating to 530°C at a rate of 83°C / h, keeping the temperature for 4 hours for aging treatment; then heating to 890°C at a heating rate of 35°C / h, keeping the temperature for 12 hours; heating to 1150°C at a heating rate of 30°C / h. Air cooling, or cooling to 930°C at a rate of 53°C / h, taking out of the furnace, and air cooling.

[0043] The prepared oriented silicon steel product was tested and its magnetic property B8 was 1.78T and iron loss P 17 / 50 It is 1.38W / kg.

[0044] Example 3 A method for preparing Cu-containing oriented silicon steel comprises the following steps: S1. The raw materials are smelted at a casting temperature of 1550°C to obtain Cu-containing oriented silicon steel ingots; the composition of the ingots is as follows: 0.06% C, 3.0% Si, 1.3% Cu, and the remainder is Fe and unavoidable impurities.

[0045] S2. Hot-roll the ingot obtained in step S1 at 1180°C to a thickness of 2.3 mm.

[0046] S3, placing the hot-rolled plate obtained in step S2 at 950° C. for normalization treatment, the heat preservation time is 10 minutes, and quenching into boiling water after the heat preservation is completed.

[0047] S4, cold rolling the normalized plate obtained after normalizing in step S3, with a cold rolling reduction rate of 87%, and cold rolling to 0.3 mm through multiple passes, and preheating at 300° C. for 10 min before cold rolling.

[0048] S5. The cold rolled sheet obtained in step S4 is subjected to decarburization annealing treatment at 850° C. for 8 minutes. The decarburization annealing atmosphere comprises, by volume percentage, 25% H2, 70% N2 and 5% water vapor.

[0049] S6. After the decarburization annealing treatment in step S5 is completed, high temperature annealing treatment is performed. The high temperature annealing conditions are: heating to 550°C at a rate of 85°C / h, keeping warm for 5 hours for aging treatment; then heating to 900°C at a heating rate of 90°C / h, keeping warm for 15 hours; heating to 1200°C at a heating rate of 45°C / h. Air cooling, or cooling to 950°C at a rate of 55°C / h, taking out of the furnace, and air cooling.

[0050] The prepared oriented silicon steel product was tested and its magnetic property B8 was 1.81T and iron loss P 17 / 50 It is 1.35W / kg.

[0051] Comparative Example 1 A method for preparing Cu-containing oriented silicon steel comprises the following steps: S1. The raw materials are smelted at a casting temperature of 1500°C to obtain Cu-containing oriented silicon steel ingots; the composition of the ingots is as follows: 0.03% C, 2.8% Si, 0.7% Cu, and the remainder is Fe and unavoidable impurities.

[0052] S2. Hot-roll the ingot obtained in step S1 at 1150°C to a thickness of 2.0 mm.

[0053] S3, placing the hot-rolled plate obtained in step S2 at 850°C for normalization treatment, the heat preservation time is 2 minutes, and quenching into boiling water after the heat preservation is completed.

[0054] S4, cold rolling the normalized plate obtained after normalizing in step S3, with a cold rolling reduction rate of 87%, and cold rolling to 0.25 mm through multiple passes, and preheating at 250° C. for 5 minutes before cold rolling.

[0055] S5. The cold rolled sheet obtained in step S4 is subjected to decarburization annealing at 835° C. for 6 minutes. The decarburization annealing atmosphere comprises, by volume percentage, 20% H2, 65% N2 and 15% water vapor.

[0056] S6. After the decarburization annealing treatment in step S5 is completed, high temperature annealing treatment is performed. The high temperature annealing conditions are: heating to 500°C at a rate of 80°C / h, keeping the temperature for 2h for aging treatment; then heating to 890°C at a heating rate of 20°C / h, keeping the temperature for 10h; heating to 1100°C at a heating rate of 15°C / h. Air cooling, or cooling to 900°C at a rate of 50°C / h, taking out of the furnace, and air cooling.

[0057] The prepared oriented silicon steel product was tested and its magnetic property B8 was 1.72T and iron loss P 17 / 50 It is 1.45W / kg. The lower Cu content makes the precipitation of single Cu particles insufficient, the magnetic induction decreases, and the iron loss increases.

[0058] Comparative Example 2 A method for preparing Cu-containing oriented silicon steel comprises the following steps: S1. The raw materials are smelted at a casting temperature of 1525°C to obtain Cu-containing oriented silicon steel ingots; the composition of the ingots is as follows: 0.05% C, 2.9% Si, 1.2% Cu, and the remainder is Fe and unavoidable impurities.

[0059] S2. Hot-roll the ingot obtained in step S1 at 1160°C to a thickness of 2.1 mm.

[0060] S3, placing the hot-rolled plate obtained in step S2 at 900°C for normalization treatment, the heat preservation time is 5 minutes, and quenching into boiling water after the heat preservation is completed.

[0061] S4, cold rolling the normalized plate obtained after normalizing in step S3, with a cold rolling reduction rate of 87%, and cold rolling to 0.27 mm through multiple passes, and preheating at 280° C. for 8 min before cold rolling.

[0062] S5. The cold rolled sheet obtained in step S4 is subjected to decarburization annealing at 840°C for 7 minutes. The decarburization annealing atmosphere comprises, by volume percentage, 23% H2, 66% N2 and 11% water vapor.

[0063] S6. After the decarburization annealing treatment in step S5 is completed, high temperature annealing treatment is performed. The high temperature annealing conditions are: heating to 530°C at a rate of 83°C / h, keeping warm for 4 hours for aging treatment; then heating to 890°C at a heating rate of 20°C / h, keeping warm for 17 hours; heating to 1100°C at a heating rate of 30°C / h. Air cooling, or cooling to 930°C at a rate of 53°C / h, taking out of the furnace, and air cooling.

[0064] The prepared oriented silicon steel product was tested and its magnetic property B8 was 1.74T and iron loss P 17 / 50 It is 1.43W / kg. Too long holding time will reduce production efficiency and deteriorate the magnetic properties of the finished product.

[0065] Comparative Example 3 A method for preparing Cu-containing oriented silicon steel comprises the following steps: S1. The raw materials are smelted at a casting temperature of 1550°C to obtain Cu-containing oriented silicon steel ingots; the composition of the ingots is as follows: 0.06% C, 3.0% Si, 1.5% Cu, and the remainder is Fe and unavoidable impurities.

[0066] S2. Hot-roll the ingot obtained in step S1 at 1180°C to a thickness of 2.3 mm.

[0067] S3, placing the hot-rolled plate obtained in step S2 at 950° C. for normalization treatment, the heat preservation time is 10 minutes, and quenching into boiling water after the heat preservation is completed.

[0068] S4, cold rolling the normalized plate obtained after normalizing in step S3, with a cold rolling reduction rate of 87%, and cold rolling to 0.3 mm through multiple passes, and preheating at 300° C. for 10 min before cold rolling.

[0069] S5. The cold rolled sheet obtained in step S4 is subjected to decarburization annealing treatment at 850° C. for 8 minutes. The decarburization annealing atmosphere comprises, by volume percentage, 25% H2, 70% N2 and 5% water vapor.

[0070] S6. After the decarburization annealing treatment in step S5 is completed, high temperature annealing treatment is performed. The high temperature annealing conditions are: heating to 550°C at a rate of 85°C / h, keeping warm for 5 hours for aging treatment; then heating to 900°C at a heating rate of 90°C / h, keeping warm for 15 hours; heating to 1200°C at a heating rate of 45°C / h. Air cooling, or cooling to 950°C at a rate of 55°C / h, taking out of the furnace, and air cooling.

[0071] The prepared oriented silicon steel product was tested and its magnetic property B8 was 1.75T and iron loss P 17 / 50 It is 1.42W / kg.

[0072] The above-described embodiments are only preferred embodiments of the present application and are not intended to limit the scope of protection of the present application. For any person skilled in the art, the present application may have various changes and modifications. Any simple equivalent changes and modifications made based on the scope of protection of the present application and the contents of the specification should be included in the scope of protection of the present application.

Claims

1. A method for preparing Cu-containing oriented silicon steel, characterized in that: The following steps are involved: S1. Smelting the raw materials to obtain Cu-containing oriented silicon steel ingot; the composition of the ingot is as follows, in terms of mass percentage: 0.03% to 0.06% C, 2.8% to 3.0% Si, 1.0% to 1.3% Cu, and the balance is Fe and unavoidable impurities; S2, hot rolling the ingot to obtain a hot-rolled plate; S3, performing normalizing treatment on the hot-rolled plate to obtain a normalized plate; S4, cold rolling the normalized sheet to obtain a cold rolled sheet; S5, performing decarburization annealing treatment on the cold-rolled sheet; S6. After the treatment in step S5 is completed, a gradient temperature annealing treatment is performed, firstly the temperature is raised to the first temperature for insulation, and then the temperature is raised to the second temperature for insulation after the insulation is completed; then the temperature is raised to the third temperature; finally, the temperature is directly air-cooled or cooled to the fourth temperature and then air-cooled to obtain a oriented silicon steel product.

2. The method for preparing Cu-containing oriented silicon steel according to claim 1, characterized in that: The casting temperature during smelting in step S1 is 1500°C ~ 1550°C.

3. The method for preparing Cu-containing oriented silicon steel according to claim 1, characterized in that: In step S2, the hot rolling temperature is 1150-1180° C.; the thickness of the hot rolled plate is 2.0-2.3 mm.

4. The method for preparing Cu-containing oriented silicon steel according to claim 1, characterized in that: The temperature of the normalization treatment in step S3 is 850-950° C., the insulation time is 2-10 min, and after the insulation is completed, the material is quenched in boiling water.

5. The method for preparing Cu-containing oriented silicon steel according to claim 1, characterized in that: In step S4, the cold rolling reduction rate is 87%; the sheet is preheated at 250-300° C. for 5-10 minutes before cold rolling; and the thickness of the cold rolled sheet is 0.25-0.3 mm.

6. The method for preparing Cu-containing oriented silicon steel according to claim 1, characterized in that: The temperature of the decarburization annealing treatment in step S5 is 835-850° C., and the holding time is 6-8 min.

7. The method for preparing Cu-containing oriented silicon steel according to claim 1, characterized in that: In terms of volume percentage, the atmosphere composition of the decarburization annealing treatment in step S5 is: 20%-25% H2, 65%-70% N2, and the rest is water vapor.

8. The method for preparing Cu-containing oriented silicon steel according to claim 1, characterized in that: In step S6, the first temperature is 500-550°C, the second temperature is 890-900°C, the third temperature is 1100-1200°C, and the fourth temperature is 900-950°C.

9. The method for preparing Cu-containing oriented silicon steel according to claim 1, characterized in that: The heating rate for heating to the first temperature is 80~85°C / h, and the holding time is 2~5h; the heating rate for heating to the second temperature is 20~90℃ / h, and the holding time is 10~15h; the heating rate for heating to the third temperature is 15~45℃ / h; the cooling rate for cooling to the fourth temperature is 50~55℃ / h.

10. Cu-containing oriented silicon steel prepared by the preparation method according to any one of claims 1 to 9.