An ultra-thin double-oriented silicon steel and a preparation method thereof

Abstract

The present invention provides an ultra-thin double-oriented silicon steel and a preparation method thereof, relating to the technical field of the preparation of ultra-thin electrical steel. The thickness of the ultra-thin double-oriented silicon steel is 0.03 - 0.10 mm, and the chemical composition by mass percentage is as follows: Si = 2.7 - 5.0%, C ≤ 0.006%, S ≤ 0.008%, Mn ≤ 0.01%, acid-soluble aluminum Als ≤ 0.008%, P ≤ 0.008%, N ≤ 0.008%, Cu ≤ 0.008%, and the balance is iron and inevitable inclusions; among them, the lower limit values of the foregoing elements cannot be 0. Without using an inhibitor, the present invention prepares an ultra-thin double-oriented silicon steel with a strong cube texture through a three-rolling process and a final high-temperature annealing process. The rolling direction and the transverse direction of the ultra-thin strip both have excellent magnetic properties. The preparation method of the ultra-thin double-oriented silicon steel disclosed by the present invention has high resource utilization rate, short process, low cost, high efficiency, and is conducive to large-scale industrial production and popularization.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of ultra-thin strip electrical steel, in particular to an ultra-thin double-oriented silicon steel and a preparation method thereof, which are applicable to fields such as high-frequency transformers, pulse transformers, and high-power magnetic amplifiers. Background Art

[0002] The industrially produced ultra-thin strip grain-oriented silicon steel generally refers to single-oriented silicon steel with a thickness ≤ 0.1 mm. As an important material in the electronic industry and the military industry, the ultra-thin strip grain-oriented silicon steel is mainly used for pulse transformers, medium-high frequency transformers, magnetic shielding of high-power magnetic amplification inductance coils, and various motors operating at a working frequency ≥ 400 Hz.

[0003] Currently, the ultra-thin strip grain-oriented silicon steel produced industrially uses grain-oriented silicon steel as raw material and is prepared by a process of one-time cold rolling and one-time recrystallization annealing. The composition of the grain-oriented silicon steel, especially the inhibitor content, needs to be strictly controlled. The preparation process is complex and there are many process control elements. It should be noted that when using grain-oriented silicon steel to prepare ultra-thin strip grain-oriented silicon steel through one-time rolling and one-time recrystallization, its magnetic properties are closely related to factors such as the characteristics of the base material, rolling method, rolling reduction rate, and annealing process.

[0004] Chinese Patent CN10831038A discloses a preparation process of ultra-thin strip grain-oriented silicon steel. This preparation process uses 0.2 - 0.3 mm grain-oriented silicon steel as raw material and prepares 0.02 mm ultra-thin strip grain-oriented silicon steel by a process of secondary cold rolling and intermediate annealing. This process is similar to the preparation process of ordinary grain-oriented silicon steel (CGO), but the magnetic induction intensity B of the prepared ultra-thin strip 10 is between 1.5 T and 1.7 T, and there is a large gap in the magnetic induction intensity compared with ordinary grain-oriented silicon steel.

[0005] Chinese Patent CN111020150A discloses a method for ultra-thin strip grain-oriented silicon steel. This preparation method uses 0.18 - 0.35 mm thick grain-oriented silicon steel as the base material. After pickling, it is cold rolled to a thickness of 0.03 - 0.10 mm. After the rolled ultra-thin strip is degreased by alkali washing and dried, it is then annealed. Obviously, the annealing process adopts a two-stage annealing, which is complex and difficult to operate. Although it can transform a single strong Goss texture (base material) into a stronger Goss texture and η texture (ultra-thin strip), the orientation degree decreases, resulting in lower magnetic properties in the rolling direction and transverse direction and higher iron loss of the prepared ultra-thin strip grain-oriented silicon steel.

[0006] Chinese Patent CN110241297A discloses an ultra-thin silicon steel strip and its preparation method. Apparently, cold rolling and annealing are adopted for the silicon steel thin strip. However, the ultra-thin silicon steel strip obtained by this method has a strong Goss texture, and the microstructure with appropriate and uniform grain size. Apparently, the magnetic properties only consider the rolling direction and do not consider the transverse direction, and in terms of the magnetic properties in the rolling direction, the magnetic induction intensity and iron loss are not ideal.

[0007] Chinese Patent CN115747445A discloses an ultra-thin cold-rolled grain-oriented silicon steel and its preparation method. This method is to perform grid stress indentation treatment on the silicon steel sheet before cold rolling, and after cold rolling, it also includes annealing, heat-resistant mechanical indentation treatment and coating; apparently, the preparation process is complex and the control difficulty is large. The heating rate of annealing is not adjusted. Although a sharp Goss texture can be formed, the improvement of the transverse magnetic properties is not considered; moreover, applying a magnetic field increases the cost, and there are many factors that need to be controlled in the process steps, which is not conducive to industrial production. Summary of the Invention

[0008] In order to solve the technical problems such as the reduction of grain orientation degree and the decrease of magnetic induction intensity caused by using grain-oriented silicon steel as the base material and preparing ultra-thin grain-oriented silicon steel by a single cold rolling and a single recrystallization annealing process in the prior art. In particular, the magnetic properties of the ultra-thin strip silicon steel prepared by some preparation methods cannot take into account both the rolling direction and the transverse direction, and the magnetic properties are poorer than those of ordinary grain-oriented silicon steel; although some preparation methods can think that in order to balance the magnetic properties in the rolling direction and the transverse direction, double orientation needs to be adopted, but the orientation degree of the double orientation prepared by the adopted method is not high; the double orientation prepared by the method adopted by some preparation methods is obtained by texture transformation on the basis of a single strong Goss texture, resulting in poor magnetic properties; some preparation methods need to perform grid stress indentation treatment on the silicon steel sheet before cold rolling, the process is complicated and the operation difficulty is large, and only the magnetic properties in the rolling direction can be enhanced; therefore, the embodiments of the present invention provide an ultra-thin strip double-oriented silicon steel and its preparation method, which have excellent magnetic properties in both the rolling direction and the transverse direction. The technical solutions are as follows:

[0009] An ultra-thin strip double-oriented silicon steel, the thickness of the ultra-thin strip double-oriented silicon steel is 0.03 - 0.10 mm, and the chemical composition is calculated by mass percentage as: Si = 2.7 - 5.0%, C ≤ 0.006%, S ≤ 0.008%, Mn ≤ 0.01%, acid-soluble aluminum Als ≤ 0.008%, P ≤ 0.008%, N ≤ 0.008%, Cu ≤ 0.008%, and the balance is iron and inevitable inclusions; among them, the lower limit values of the foregoing elements cannot be 0.

[0010] Optionally, the content of the cube texture in the ultra-thin strip double-oriented silicon steel is 85% or more, and the grain size is 1 - 8 mm.

[0011] Optionally, when the mass content of silicon in the ultra-thin strip bi-oriented silicon steel is 3%, the magnetic induction intensity B in the rolling direction is 8 ≥1.82T, iron loss P 17 / 50 ≤0.8W / kg; transverse magnetic induction intensity B 8 ≥1.79T, iron loss P 17 / 50 ≤0.85W / kg; iron loss in rolling direction and transverse direction P 15 / 400 ≤17W / kg;

[0012] When the mass content of silicon is 3.5%, the magnetic induction intensity B in the rolling direction is 8 ≥1.80T, P 17 / 50 ≤0.75W / kg; transverse magnetic induction intensity B 8 ≥1.77T, P 17 / 50 ≤0.8W / kg; iron loss in rolling direction and transverse direction P 15 / 400 ≤16W / kg;

[0013] When the mass content of silicon is 4.5%, the magnetic induction intensity B in the rolling direction is 8 ≥1.75T, P 17 / 50 ≤0.7W / kg; transverse magnetic induction intensity B 8 ≥1.72T, P 17 / 50 ≤0.75W / kg; iron loss in rolling direction and transverse direction P 15 / 400 ≤14W / kg.

[0014] A method for preparing the ultra-thin strip bi-oriented silicon steel is provided, wherein the method comprises the following steps:

[0015] S1. Smelting: pure silicon and industrial pure iron are mixed according to the composition ratio, melted and refined in a vacuum induction furnace, and cast to obtain an ingot;

[0016] S2, cogging: Cogging the S1 ingot of required quality to obtain a rectangular billet;

[0017] S3, hot rolling: after the rectangular billet in S2 is charged into a furnace at room temperature, it is heated and hot rolled in multiple passes to obtain a hot-rolled plate;

[0018] S4, primary cold rolling: the S3 hot-rolled sheet is pickled, and then subjected to multiple cold rolling passes to obtain a primary cold-rolled sheet;

[0019] S5, primary intermediate annealing: performing a primary intermediate annealing on the primary cold rolled sheet in S4 to obtain a primary annealed cold rolled sheet;

[0020] S6, secondary cold rolling: the S5 primary annealing cold rolled sheet is subjected to multiple cold rolling passes to obtain a secondary cold rolled sheet;

[0021] S7. Secondary intermediate annealing: The S6 secondary cold-rolled sheet is subjected to secondary intermediate annealing to obtain a secondary annealed cold-rolled sheet;

[0022] S8. Tertiary cold rolling: The S7 secondary annealed cold-rolled sheet is subjected to multi-pass cold rolling to obtain a tertiary cold-rolled sheet;

[0023] S9. High-temperature annealing: The S8 tertiary cold-rolled sheet is subjected to high-temperature annealing in a weakly oxidizing atmosphere to obtain an ultra-thin double-oriented silicon steel sheet.

[0024] Optionally, in S1, the proportion of pure silicon to industrial pure iron in the batching is (2.8 - 5.2):(97.2 - 94.8), the melting temperature in the vacuum induction furnace is 1600 - 1650 °C, the refining temperature is 1550 - 1600 °C, and the casting temperature is 1500 - 1550 °C.

[0025] Optionally, in S2, the blooming is carried out by mechanical free forging, forging with an air hammer in the range of 800 - 1100 °C, and after multiple upsetting and drawing, a rectangular billet is obtained, or a rectangular billet is obtained by blooming and rolling with a roughing mill.

[0026] Optionally, in S2, the thickness range of the rectangular billet is 15 - 30 mm.

[0027] Optionally, in S3, the hot rolling temperature is 850 - 1050 °C, the heating rate is 10 - 800 °C / min, the holding time after heating to the aforementioned temperature is 5 - 30 min, three-pass hot rolling is adopted, and the furnace is held for heat preservation for 5 - 20 min between passes; the grains of the hot-rolled sheet are equiaxed grains, the grain size is 200 - 800 μm, and the thickness of the hot-rolled sheet is 1.4 - 2.6 mm.

[0028] Optionally, in S4, the temperature of multi-pass cold rolling is 10 - 400 °C, the heating rate is 10 - 800 °C / min, the holding time after heating to the aforementioned temperature is 3 - 30 min, and the furnace is held for heat preservation for 3 - 20 min between passes; the thickness of the primary cold-rolled sheet is 0.4 - 0.8 mm.

[0029] Optionally, the temperature of multi-pass cold rolling in S4 corresponds to the silicon content in the hot-rolled sheet. When the silicon content is 3.5% Si, the holding temperature is 10 - 100 °C, when the silicon content is 4.5% Si, the holding temperature is 280 - 330 °C, and when the silicon content is 5%, the holding temperature is 350 - 400 °C;

[0030] The reduction ratio of the primary cold rolling is 55 - 75%, the reduction ratio per pass is 10 - 30%, and the reduction ratio of the last pass does not exceed 15%.

[0031] Optionally, the temperatures of the first intermediate annealing and the second intermediate annealing corresponding to S5 and S7 are both 950 - 1200 °C, the heating rates are both 10 - 800 °C / min, and the holding times are both 1 - 30 min.

[0032] Optionally, the reduction ratios of the second cold rolling and the third cold rolling corresponding to S6 and S8 are 55 - 75%, and the reduction ratio of the last pass of the second cold rolling is not greater than 10%.

[0033] Optionally, the thicknesses of the second cold rolling and the third cold rolling corresponding to S6 and S8 are 0.12 - 0.3 mm and 0.03 - 0.10 mm, respectively.

[0034] Optionally, the time of high - temperature annealing in S9 is inversely proportional to the temperature: the higher the temperature, the shorter the time.

[0035] Optionally, the temperature of high - temperature annealing in S9 is 1050 - 1300 °C, the annealing atmosphere is a weakly oxidizing atmosphere (or a weakly SO 2 atmosphere, H 2 S atmosphere), and the holding time is 0.5 - 24 h.

[0036] Optionally, the grains of the ultra - thin strip double - oriented silicon steel after high - temperature annealing in S9 are visible to the naked eye, and the grain size is concentrated in the range of 1 - 8 mm.

[0037] The technical principle of the present invention:

[0038] The present invention obtains a strong Goss texture ({110}<001>) and a relatively strong λ texture (<001> / / ND) by controlling the hot - rolling process. Under appropriate cold - rolling reduction ratios and annealing processes, the Goss texture and the λ texture can be well inherited in the microstructure. After the third rolling and primary recrystallization, the primary recrystallized grains of the ultra - thin strip are mainly strong Goss and cube textures. During the long - time high - temperature annealing process, driven by the surface energy, the cube texture undergoes abnormal growth and secondary recrystallization under a specific atmosphere, thereby obtaining an ultra - thin strip double - oriented silicon steel with a strong cube texture content of 85% or more.

[0039] The above - mentioned technical solution has at least the following beneficial effects compared with the prior art:

[0040] The above - mentioned solution, the present invention provides an ultra - thin strip double - oriented silicon steel and a preparation method, which can solve many technical problems existing in the preparation process of the oriented silicon steel ultra - thin strip, thereby reducing production costs and improving economic benefits.

[0041] The present invention uses industrial pure iron and pure silicon as raw materials to prepare ultra-thin strip dual-oriented silicon steel without adding any inhibitors and rare earth elements, and the alloy composition of high silicon steel is slightly changed. Ultra-thin strip oriented silicon steel with a thickness of ≤0.1mm is prepared. The process flow is short, the efficiency is high, the raw materials are easy to obtain, and the cost advantage of industrialization is very obvious.

[0042] The present invention obtains a strong Goss texture ({110} <001> ) and a stronger λ texture ( <001> / / ND), by controlling the rolling reduction rate of the three cold rolling processes and the annealing temperature and time of the three annealing processes, the strong Goss texture and λ texture can be well inherited by the organization, and the cubic grains can swallow up the grains of other orientations to obtain a single strong cubic texture, which synergistically improves the magnetic properties in the rolling direction and the transverse direction, and increases the application range of silicon steel thin strips.

[0043] After the third rolling and primary recrystallization of the present invention, the primary recrystallized grains of the ultra-thin strip are mainly strong Goss and cubic textures, and the grain size is 30-80 μm; after high temperature annealing, the grain size is 1-8 mm

[0044] When the mass content of silicon in the ultra-thin strip bi-oriented silicon steel of the present invention is 3%, the magnetic induction intensity B in the rolling direction is 8 ≥1.82T, iron loss P 17 / 50 ≤0.8W / kg; transverse magnetic induction intensity B 8 ≥1.79T, iron loss P 17 / 50 ≤0.85W / kg; iron loss in rolling direction and transverse direction P 15 / 400 ≤17W / kg;

[0045] When the mass content of silicon is 3.5%, the magnetic induction intensity B in the rolling direction is 8 ≥1.80T, P 17 / 50 ≤0.75W / kg; transverse magnetic induction intensity B 8 ≥1.77T, P 17 / 50 ≤0.8W / kg; iron loss in rolling direction and transverse direction P 15 / 400 ≤16W / kg;

[0046] When the mass content of silicon is 4.5%, the magnetic induction intensity B in the rolling direction is 8 ≥1.75T, P 17 / 50 ≤0.7W / kg; transverse magnetic induction intensity B 8 ≥1.72T, P 17 / 50 ≤0.75W / kg; iron loss in rolling direction and transverse direction P 15 / 400 ≤14W / kg.

[0047] In summary, compared with other traditional methods, the method of the present invention obtains an ultra-thin double-oriented silicon steel with excellent magnetic properties by selecting components, controlling the hot rolling process to obtain a strong Goss texture, and regulating the orientation in the silicon steel by using a three-time cold rolling process and a three-time annealing process; it can synergistically improve the magnetic properties in the rolling direction and transverse direction of the ultra-thin silicon steel strip, with high resource utilization rate, short process flow, high efficiency, and is conducive to large-scale industrial production and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for description in the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0049] Figure 1 is a process flow chart of a method for preparing an ultra-thin double-oriented silicon steel of the present invention;

[0050] Figure 2 is a macroscopic morphology diagram of an ultra-thin double-oriented silicon steel prepared by a method for preparing an ultra-thin double-oriented silicon steel provided in Embodiment 3 of the present invention;

[0051] Figure 3 is a macroscopic texture diagram of the surface layer of an ultra-thin double-oriented silicon steel prepared by a method for preparing an ultra-thin double-oriented silicon steel provided in Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] The following will describe the technical solutions in the present invention with reference to the drawings.

[0053] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "example" in the present invention should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of the word "example" is intended to present concepts in a specific manner. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one of the two.

[0054] In the embodiments of the present invention, "image" and "picture" can sometimes be used interchangeably. It should be noted that when their differences are not emphasized, the meanings they express are the same. "Of", "corresponding" and "correspondent" can sometimes be used interchangeably. It should be noted that when their differences are not emphasized, the meanings they express are the same.

[0055] In the embodiments of the present invention, sometimes subscripts such as W 1 may be written in a non-subscript form such as W1. When their differences are not emphasized, the meanings they express are the same.

[0056] To make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments.

[0057] An ultra-thin double-oriented silicon steel, the thickness of the ultra-thin double-oriented silicon steel is 0.03 - 0.10 mm, and the chemical composition by mass percentage is: Si = 2.7 - 5.0%, C ≤ 0.006%, S ≤ 0.008%, Mn ≤ 0.01%, acid-soluble aluminum Als ≤ 0.008%, P ≤ 0.008%, N ≤ 0.008%, Cu ≤ 0.008%, and the balance is iron and inevitable inclusions; among them, the lower limit value of each of the foregoing elements cannot be 0.

[0058] In particular, the content of the cube texture in the ultra-thin double-oriented silicon steel is 85% or more, and the grain size is 1 - 8 mm.

[0059] In particular, when the mass content of silicon in the ultra-thin double-oriented silicon steel is 3%, the magnetic induction intensity B in the rolling direction 8 ≥1.82 T, and the iron loss P 17 / 50 ≤0.8 W / kg; the magnetic induction intensity B in the transverse direction 8 ≥1.79 T, and the iron loss P 17 / 50 ≤0.85 W / kg; the iron loss P in the rolling direction and the transverse direction 15 / 400 ≤17 W / kg;

[0060] When the mass content of silicon is 3.5%, the magnetic induction intensity B in the rolling direction 8 ≥1.80 T, and P 17 / 50 ≤0.75 W / kg; the magnetic induction intensity B in the transverse direction 8 ≥1.77 T, and P 17 / 50 ≤0.8 W / kg; the iron loss P in the rolling direction and the transverse direction 15 / 400 ≤16 W / kg;

[0061] When the mass content of silicon is 4.5%, the magnetic induction intensity B in the rolling direction 8 ≥1.75 T, and P 17 / 50 ≤0.7 W / kg; the magnetic induction intensity B in the transverse direction 8 ≥1.72 T, and P 17 / 50 ≤0.75 W / kg; the iron loss P in the rolling direction and the transverse direction 15 / 400 ≤14 W / kg.

[0062] A preparation method based on the above-mentioned ultra-thin double-oriented silicon steel, the preparation method of the ultra-thin double-oriented silicon steel combines Figure 1 the following steps:

[0063] S1. Melting: Pure silicon and industrial pure iron are proportioned according to the composition ratio, melted by a vacuum induction furnace and then refined, and ingots are obtained by casting.

[0064] S2. Blooming: The ingots obtained in S1 with the required mass are bloomed to obtain rectangular billets.

[0065] S3. Hot rolling: The rectangular billets in S2 are heated after being charged into the furnace at room temperature and then subjected to multi-pass hot rolling to obtain hot-rolled sheets.

[0066] S4. First cold rolling: The hot-rolled sheets in S3 are pickled and then subjected to multi-pass cold rolling to obtain first cold-rolled sheets.

[0067] S5. First intermediate annealing: The first cold-rolled sheets in S4 are subjected to first intermediate annealing to obtain first annealed cold-rolled sheets.

[0068] S6. Second cold rolling: The first annealed cold-rolled sheets in S5 are subjected to multi-pass cold rolling to obtain second cold-rolled sheets.

[0069] S7. Second intermediate annealing: The second cold-rolled sheets in S6 are subjected to second intermediate annealing to obtain second annealed cold-rolled sheets.

[0070] S8. Third cold rolling: The second annealed cold-rolled sheets in S7 are subjected to multi-pass cold rolling to obtain third cold-rolled sheets.

[0071] S9. High-temperature annealing: The third cold-rolled sheets in S8 are subjected to high-temperature annealing in a weakly oxidizing atmosphere to obtain ultra-thin double-oriented silicon steel sheets.

[0072] In particular, in S1, the proportioning ratio of pure silicon to industrial pure iron is (2.8 - 5.2):(97.2 - 94.8), the melting temperature of the vacuum induction furnace is 1600 - 1650 °C, the refining temperature is 1550 - 1600 °C, and the casting temperature is 1500 - 1550 °C.

[0073] In particular, in S2, blooming is carried out by mechanical free forging. Forging is carried out with an air hammer in the range of 800 - 1100 °C, and after multiple upsetting and drawing operations, rectangular billets are obtained, or rectangular billets are obtained by blooming and rolling with a roughing mill.

[0074] In particular, in S2, the thickness range of the rectangular billets is 15 - 30 mm.

[0075] In particular, in S3, the hot rolling temperature is 850 - 1050 °C, the heating rate is 10 - 800 °C / min, the holding time after heating to the aforementioned temperature is 5 - 30 min, three-pass hot rolling is adopted, and the furnace is held for heat preservation for 5 - 20 min between passes; the grains of the hot-rolled sheets are equiaxed grains, the grain size is 200 - 800 μm, and the thickness of the hot-rolled sheets is 1.4 - 2.6 mm.

[0076] Specifically, the temperature for multi-pass cold rolling in S4 is 10 - 400°C, the heating rate is 10 - 800°C / min, the holding time after heating to the aforementioned temperature is 3 - 30 min, and the re-heating holding time between passes is 3 - 20 min; the thickness of the single-pass cold-rolled sheet is 0.4 - 0.8 mm.

[0077] Specifically, the temperature for multi-pass cold rolling in S4 corresponds to the silicon content in the hot-rolled sheet. When the silicon content is 3.5% Si, the holding temperature is 10 - 100°C; when the silicon content is 4.5% Si, the holding temperature is 280 - 330°C; when the silicon content is 5%, the holding temperature is 350 - 400°C.

[0078] The reduction ratio of the single-pass cold rolling is 55 - 75%, the reduction ratio of each pass is 10 - 30%, and the reduction ratio of the last pass does not exceed 15%.

[0079] Specifically, the temperatures for the first intermediate annealing and the second intermediate annealing corresponding to S5 and S7 are both 950 - 1200°C, the heating rates are both 10 - 800°C / min, and the holding times are both 1 - 30 min.

[0080] Specifically, the reduction ratios for the second cold rolling and the third cold rolling corresponding to S6 and S8 are 55 - 75%, and the reduction ratio of the last pass of the second cold rolling is not more than 10%.

[0081] Specifically, the thicknesses of the second cold rolling and the third cold rolling corresponding to S6 and S8 are 0.12 - 0.3 mm and 0.03 - 0.10 mm, respectively.

[0082] Specifically, the time for high-temperature annealing in S9 is inversely proportional to the temperature: the higher the temperature, the shorter the time.

[0083] Specifically, the temperature for high-temperature annealing in S9 is 1050 - 1300°C, the annealing atmosphere is a weakly oxidizing atmosphere (or a weakly SO 2 atmosphere, H 2 S atmosphere), and the holding time is 0.5 - 24 h.

[0084] Specifically, after high-temperature annealing in S9, the grains of the ultra-thin double-oriented silicon steel are visible to the naked eye, and the grain size is concentrated in the range of 1 - 8 mm.

[0085] Example 1

[0086] An ultra-thin double-oriented silicon steel, the thickness of the ultra-thin double-oriented silicon steel is 0.08 mm, and the chemical composition by mass percentage is: Si 4.64%, C 0.003%, S 0.002%, Mn 0.009%, acid-soluble aluminum Als 0.006%, P 0.005%, N 0.003%, Cu 0.004%, and the balance is iron and unavoidable inclusions.

[0087] A method for preparing the ultra-thin strip bi-oriented silicon steel is provided, wherein the method comprises the following steps:

[0088] S1. Smelting: pure silicon and industrial pure iron are mixed according to the composition ratio, the ratio of pure silicon to industrial pure iron is 4.7:95.3, and then refined by melting in a vacuum induction furnace, the melting temperature of the vacuum induction furnace is 1610°C, the refining temperature is 1570°C, and casting is performed at a casting temperature of 1510°C to obtain an ingot;

[0089] S2, blanking: blanking the S1 ingot of required quality, blanking is carried out by mechanical free forging, forging at 850-1100℃ by air hammer, and rectangular blank is obtained after multiple upsetting and drawing, and the thickness of the rectangular blank is 25mm;

[0090] S3, hot rolling: after the S2 rectangular billet is charged into a furnace at room temperature, it is heated and subjected to multiple hot rolling passes. The hot rolling temperature is 1050°C, the heating rate is 10°C / min, and the holding time after heating to the aforementioned temperature is 30min. Three hot rolling passes are adopted, and the hot rolling is carried out for 5min between passes to obtain a hot rolled plate. The grains of the hot rolled plate are equiaxed grains, the average grain size is 300μm, and the thickness of the hot rolled plate is 1.6mm.

[0091] S4, one-pass cold rolling: pickling the S3 hot-rolled plate, and then performing multiple cold rolling, the temperature of the multiple cold rolling is 300°C, the heating rate is 10°C / min, the holding time after heating to the above temperature is 5min, the reduction rate in one rolling is 68%, the pass reduction rate is 10-30%, each pass is returned to the furnace for 5min, and the plate is rolled to 0.5mm through 4-5 passes, and the last pass reduction rate is 10% to obtain a one-pass cold rolled plate;

[0092] S5, primary intermediate annealing: perform a primary intermediate annealing on the primary cold-rolled sheet of S4, the primary intermediate annealing temperature is 1100°C, the heating rate is 10°C / min, the holding time is 5min, and a primary annealed cold-rolled sheet is obtained;

[0093] S6, secondary cold rolling: the S5 once annealed cold rolled sheet is subjected to multiple cold rolling, with a rolling reduction rate of 60%, a pass reduction rate of 5-30%, and rolled to 0.2mm through 4-5 passes, and a last pass rolling reduction rate of 5% to obtain a secondary cold rolled sheet;

[0094] S7, secondary intermediate annealing: the S6 secondary cold-rolled sheet is subjected to secondary intermediate annealing, the secondary intermediate annealing temperature is 1050°C, the heating rate is 10°C / min, the holding time is 5min, and the secondary annealed cold-rolled sheet is obtained;

[0095] S8. Tertiary cold rolling: The S7 second annealed cold rolled sheet is subjected to multi-pass cold rolling with a rolling reduction rate of 60%, a per-pass reduction rate of 5-30%, rolled to 0.08 mm through 4-5 passes, and the rolling reduction rate of the last pass is 5% to obtain a tertiary cold rolled sheet;

[0096] S9. High-temperature annealing: The S8 tertiary cold rolled sheet is subjected to high-temperature annealing in a weakly oxidizing atmosphere at 1100 °C for 12 h to obtain an ultra-thin double-oriented silicon steel.

[0097] In S9 of this embodiment, the grains of the ultra-thin double-oriented silicon steel after high-temperature annealing are visible to the naked eye, and the grain size is concentrated in 1-7 mm.

[0098] As Figure 3 shown, the surface macrotexture of the prepared ultra-thin double-oriented silicon steel is a strong cube texture with an orientation density of 39.6.

[0099] In the ultra-thin double-oriented silicon prepared in this embodiment, the content of the cube texture is 90%, and the average grain size is 4 mm.

[0100] When the mass content of silicon in the ultra-thin double-oriented silicon steel prepared in this embodiment is 4.64%, the magnetic induction intensity B in the rolling direction 8 = 1.76 T, P 17 / 50 = 0.68 W / kg, P 15 / 400 = 12.4 W / kg; the magnetic induction intensity B in the transverse direction 8 = 1.73 T, P 17 / 50 = 0.73 W / kg, P 15 / 400 = 12.7 W / kg.

[0101] Example 2

[0102] An ultra-thin double-oriented silicon steel, the thickness of the ultra-thin double-oriented silicon steel is 0.05 mm, and the chemical composition by mass percentage is: Si 3.6%, C 0.004%, S 0.003%, Mn 0.008%, acid-soluble aluminum Als 0.007%, P 0.007%, N 0.002%, Cu 0.003%, and the balance is iron and unavoidable inclusions.

[0103] A preparation method based on the above ultra-thin double-oriented silicon steel, the preparation method of the ultra-thin double-oriented silicon steel is as follows:

[0104] S1. Melting: Pure silicon and industrial pure iron are proportioned according to the component ratio, and the proportioning ratio of pure silicon and industrial pure iron is 3.7:96.3. After melting and refining using a vacuum induction furnace, the melting temperature of the vacuum induction furnace is 1630 °C, the refining temperature is 1580 °C, and casting is carried out at a casting temperature of 1530 °C to obtain an ingot;

[0105] S2. Blooming: The ingot of S1 with the required quality is bloomed. The blooming is carried out by mechanical free forging. It is forged with an air hammer at 850 - 1100 °C, and after multiple upsetting and drawing operations, a rectangular billet is obtained. The thickness of the rectangular billet is 20 mm.

[0106] S3. Hot rolling: After the rectangular billet of S2 is charged into the furnace at room temperature and heated, multi-pass hot rolling is carried out. The hot rolling temperature is 1050 °C, the heating rate is 15 °C / min, the holding time after heating to the aforementioned temperature is 30 min, and three passes of hot rolling are adopted. The furnace is returned for heat preservation for 6 min between passes, and a hot rolled sheet is obtained. The grains of the hot rolled sheet are equiaxed grains, the average grain size is 330 μm, and the thickness of the hot rolled sheet is 2.0 mm.

[0107] S4. First cold rolling: The hot rolled sheet of S3 is pickled and then multi-pass cold rolling is carried out. The temperature of multi-pass cold rolling is room temperature. The reduction ratio in the first pass is 70%, the reduction ratio per pass is 10 - 30%, and the furnace is returned for heat preservation for 5 min for each pass. After 4 - 5 passes of rolling to 0.6 mm, the reduction ratio in the last pass is 12%, and a first cold rolled sheet is obtained.

[0108] S5. First intermediate annealing: The first cold rolled sheet of S4 is subjected to first intermediate annealing. The temperature of the first intermediate annealing is 1000 °C, the heating rate is 15 °C / min, and the holding time is 10 min, and a first annealed cold rolled sheet is obtained.

[0109] S6. Second cold rolling: The first annealed cold rolled sheet of S5 is subjected to multi-pass cold rolling. The rolling reduction ratio is 70%, the reduction ratio per pass is 5 - 30%, and after 4 - 5 passes of rolling to 0.18 mm, the rolling reduction ratio in the last pass is 10%, and a second cold rolled sheet is obtained.

[0110] S7. Second intermediate annealing: The second cold rolled sheet of S6 is subjected to second intermediate annealing. The temperature of the second intermediate annealing is 1000 °C, the heating rate is 15 °C / min, and the holding time is 10 min, and a second annealed cold rolled sheet is obtained.

[0111] S8. Third cold rolling: The second annealed cold rolled sheet of S7 is subjected to multi-pass cold rolling. The rolling reduction ratio is 72%, the reduction ratio per pass is 5 - 30%, and after 4 - 5 passes of rolling to 0.05 mm, the rolling reduction ratio in the last pass is 5%, and a third cold rolled sheet is obtained.

[0112] S9. High temperature annealing: The third cold rolled sheet of S8 is subjected to high temperature annealing in a weakly oxidizing atmosphere at 1200 °C for 4 h, and an ultra-thin double-oriented silicon steel is obtained.

[0113] In S9 of this embodiment, the grains of the ultra-thin double-oriented silicon steel after high temperature annealing are visible to the naked eye, and the grain size is concentrated in 3 - 8 mm.

[0114] The content of cubic texture in the ultra-thin strip bi-oriented silicon steel prepared in this embodiment is 88%, and the average grain size is 5 mm.

[0115] When the mass content of silicon in the ultra-thin dual-oriented silicon steel prepared in this embodiment is 3.6%, the magnetic induction intensity B 8 =1.81T,P 17 / 50 =0.74W / kg, P 15 / 400 =14.1W / kg; transverse magnetic induction intensity B 8 =1.78T,P 17 / 50 =0.78W / kg, P 15 / 400 =14.4W / kg.

[0116] Example 3

[0117] The invention discloses an ultra-thin strip bi-oriented silicon steel, which has a thickness of 0.10 mm and chemical compositions as follows by mass percentage: Si 2.9%, C 0.005%, S 0.002%, Mn 0.006%, acid-soluble aluminum Als 0.005%, P 0.004%, N 0.004%, Cu 0.005%, and the balance is iron and unavoidable inclusions.

[0118] A method for preparing the ultra-thin strip bi-oriented silicon steel is provided, wherein the method comprises the following steps:

[0119] S1. Smelting: pure silicon and industrial pure iron are mixed according to the composition ratio, the ratio of pure silicon to industrial pure iron is 3:97, and then refined by melting in a vacuum induction furnace, the melting temperature of the vacuum induction furnace is 1640°C, the refining temperature is 1590°C, and the casting temperature is 1540°C to obtain an ingot;

[0120] S2, blanking: blanking the S1 ingot of required quality, blanking is carried out by mechanical free forging, forging at 850-1100℃ by air hammer, and rectangular blank is obtained after multiple upsetting and drawing, and the thickness of the rectangular blank is 25mm;

[0121] S3, hot rolling: after the S2 rectangular billet is charged into a furnace at room temperature, it is heated and hot rolled for multiple passes. The hot rolling temperature is 1050°C, the heating rate is 100°C / min, and the holding time after heating to the above temperature is 30min. Three hot rolling processes are adopted, and the hot rolling is carried out for 8min between the passes to obtain a hot rolled plate. The grains of the hot rolled plate are equiaxed grains, the average grain size is 500μm, and the thickness of the hot rolled plate is 2.6mm.

[0122] S4. First cold rolling: Pickle the hot-rolled sheet in S3, then perform multi-pass cold rolling. The temperature for multi-pass cold rolling is room temperature. The reduction rate for the first rolling is 69%, the reduction rate per pass is 10 - 30%, and it is rolled to 0.8 mm after 4 - 5 passes. The reduction rate for the last pass is 15% to obtain the first cold-rolled sheet;

[0123] S5. First intermediate annealing: Perform first intermediate annealing on the first cold-rolled sheet in S4. The temperature for the first intermediate annealing is 1050 °C, the heating rate is 200 °C / min, and the holding time is 8 min to obtain the first annealed cold-rolled sheet;

[0124] S6. Second cold rolling: Perform multi-pass cold rolling on the first annealed cold-rolled sheet in S5. The rolling reduction rate is 65%, the reduction rate per pass is 5 - 30%, and it is rolled to 0.28 mm after 4 - 5 passes. The rolling reduction rate for the last pass is 10% to obtain the second cold-rolled sheet;

[0125] S7. Second intermediate annealing: Perform second intermediate annealing on the second cold-rolled sheet in S6. The temperature for the second intermediate annealing is 1050 °C, the heating rate is 200 °C / min, and the holding time is 8 min to obtain the second annealed cold-rolled sheet;

[0126] S8. Third cold rolling: Perform multi-pass cold rolling on the second annealed cold-rolled sheet in S7. The rolling reduction rate is 64%, the reduction rate per pass is 5 - 30%, and it is rolled to 0.10 mm after 4 - 5 passes. The rolling reduction rate for the last pass is 5% to obtain the third cold-rolled sheet;

[0127] S9. High-temperature annealing: Perform high-temperature annealing on the third cold-rolled sheet in S8 at 1250 °C in a weak SO 2 atmosphere for 2 h to obtain the ultra-thin double-oriented silicon steel.

[0128] In S9 of this embodiment, the grains of the ultra-thin double-oriented silicon steel after high-temperature annealing are visible to the naked eye, and the grain size is concentrated in the range of 2 - 8 mm.

[0129] As Figure 2 shown, the macroscopic morphology of the prepared ultra-thin double-oriented silicon steel shows that the grains are visible to the naked eye, and the grain size is concentrated in the range of 2 - 8 mm.

[0130] In the ultra-thin double-oriented silicon steel prepared in this embodiment, the content of the cube texture is 86%, and the average grain size is 4 mm.

[0131] When the mass content of silicon in the ultra-thin double-oriented silicon steel prepared in this embodiment is 2.9%, the magnetic induction intensity B 8 = 1.86 T, P 17 / 50 = 0.78 W / kg, P 15 / 400 = 15.4 W / kg; the magnetic induction intensity B 8 = 1.84 T, P17 / 50 = 0.82 W / kg, P 15 / 400 = 15.6 W / kg.

[0132] Comparative Example 1

[0133] An ultra-thin strip silicon steel, the thickness of the ultra-thin strip silicon steel is 0.08 mm, and the chemical composition by mass percentage is: Si 4.64%, C 0.003%, S 0.002%, Mn 0.009%, acid-soluble aluminum Als 0.006%, P 0.005%, N 0.003%, Cu 0.004%, and the balance is iron and inevitable inclusions.

[0134] A preparation method based on the above ultra-thin strip silicon steel, and the preparation method of the ultra-thin strip silicon steel is as follows:

[0135] S1. Melting: Pure silicon and industrial pure iron are proportioned according to the component ratio. The proportioning ratio of pure silicon and industrial pure iron is 4.7:95.3. After melting and refining by a vacuum induction furnace, the melting temperature of the vacuum induction furnace is 1610 °C, the refining temperature is 1570 °C, and casting is carried out. The casting temperature is 1510 °C to obtain an ingot.

[0136] S2. Blooming: The ingot of S1 with the required mass is bloomed. The blooming adopts the mechanical free forging method and is forged by an air hammer at 850 - 1100 °C. After multiple upsetting and drawing, a rectangular blank is obtained; the thickness of the rectangular blank is 25 mm.

[0137] S3. Hot rolling: After the rectangular blank of S2 is charged into the furnace at room temperature and heated, multi-pass hot rolling is carried out. The hot rolling temperature is 1050 °C, the heating rate is 10 °C / min, the holding time after heating to the aforementioned temperature is 30 min, and three-pass hot rolling is adopted. The furnace is held for 5 min between passes to obtain a hot rolled plate; the grains of the hot rolled plate are equiaxed grains, the average grain size is 300 μm, and the thickness of the hot rolled plate is 1.6 mm.

[0138] S4. First large reduction rate rolling: After the hot rolled plate is pickled, it is held at 300 °C for 10 min and then rolled. The reduction rate per pass is 10 - 30%, and the furnace is held for 5 min for each pass. After being warm rolled to 0.5 mm through 5 passes, it is cold rolled to 0.08 mm at room temperature through multiple passes to obtain a cold rolled plate, and the rolling reduction rate is 95%.

[0139] S5. High temperature annealing: The cold rolled plate of S4 is annealed in an argon protection atmosphere, held at 1100 °C for 12 h to obtain an ultra-thin strip silicon steel.

[0140] The grain size of the ultra-thin strip silicon steel after high temperature annealing in S5 of this comparative example is 150 - 300 µm.

[0141] The ultra-thin strip silicon steel prepared in this comparative example is mainly composed of γ texture (<111> / / ND), the content of cube texture is close to 0, and the average grain size is 248μm.

[0142] When the mass content of silicon in the ultra-thin strip silicon steel prepared in this comparative example is 4.64%, the magnetic induction intensity B in the rolling direction 8 = 1.35T, P 17 / 50 = 2.76W / kg; the magnetic induction intensity B in the transverse direction 8 = 1.33T, P 17 / 50 = 2.88W / kg.

[0143] Compared with Comparative Example 1, in Example 1, the texture of the ultra-thin strip was regulated by a three-pass rolling process. After long-time high-temperature annealing, the content of cube texture in the obtained ultra-thin strip was 90%, while in Comparative Example 1, one-pass high reduction rolling and high-temperature annealing were used, and the content of cube texture in the obtained ultra-thin strip was close to 0. The ultra-thin strip in Example 1 has excellent magnetic properties, with B 8 = 1.76T, P 17 / 50 = 0.68W / kg; while the magnetic properties of the ultra-thin strip in Comparative Example 1 are very poor, the magnetic induction intensity B in the rolling direction 8 = 1.35T, P 17 / 50 = 2.76W / kg.

[0144] Comparative Example 2

[0145] An ultra-thin strip silicon steel, the thickness of the ultra-thin strip silicon steel is 0.05mm, and the chemical composition by mass percentage is: Si 3.6%, C 0.004%, S 0.003%, Mn 0.008%, acid-soluble aluminum Als 0.007%, P 0.007%, N 0.002%, Cu 0.003%, and the balance is iron and inevitable inclusions.

[0146] A preparation method based on the above ultra-thin strip silicon steel, the preparation method of the ultra-thin strip silicon steel is as follows:

[0147] S1. Melting: Pure silicon and industrial pure iron are proportioned according to the component ratio, and the proportioning ratio of pure silicon and industrial pure iron is 3.7:96.3. After melting with a vacuum induction furnace and then refining, the melting temperature of the vacuum induction furnace is 1630°C, the refining temperature is 1580°C, and casting is carried out at a casting temperature of 1530°C to obtain an ingot;

[0148] S2. Blooming: The ingot obtained in S1 with the required mass is bloomed. The blooming is carried out by mechanical free forging, and forged with an air hammer at 850 - 1100°C. After multiple upsetting and drawing, a rectangular billet is obtained; the thickness of the rectangular billet is 20mm;

[0149] S3. Hot rolling: After the rectangular billet in S2 is charged into the furnace at room temperature, it is heated and subjected to multi-pass hot rolling. The hot rolling temperature is 1050 °C, the heating rate is 15 °C / min, the holding time after heating to the aforementioned temperature is 30 min, and three-pass hot rolling is adopted. The furnace is held for 6 min between passes to obtain a hot-rolled plate; the grains of the hot-rolled plate are equiaxed grains, the grain size is 350 μm, and the thickness of the hot-rolled plate is 2.0 mm;

[0150] S4. First cold rolling: The hot-rolled plate in S3 is pickled and then subjected to multi-pass cold rolling. The temperature of multi-pass cold rolling is room temperature. The reduction rate during the first rolling is 82.5%. After 6 passes of rolling to 0.35 mm, a first cold-rolled plate is obtained;

[0151] S5. First intermediate annealing: The first cold-rolled plate in S4 is subjected to first intermediate annealing. The temperature of the first intermediate annealing is 1000 °C, the heating rate is 15 °C / min, and the holding time is 10 min to obtain a first annealed cold-rolled plate;

[0152] S6. Second cold rolling: The first annealed cold-rolled plate in S5 is subjected to multi-pass cold rolling. The rolling reduction rate is 86%. After multi-pass rolling to 0.05 mm, a second cold-rolled plate is obtained;

[0153] S7. High-temperature annealing: The second cold-rolled plate in S6 is annealed in a weakly oxidizing atmosphere at 1200 °C for 4 h to obtain an ultra-thin strip silicon steel.

[0154] In this comparative example, the grain size of the ultra-thin strip silicon steel after high-temperature annealing in S5 is 80 - 180 µm.

[0155] The ultra-thin strip silicon steel prepared in this comparative example has a strong γ texture (<111> / / ND) and {114}<481>. The content of the cube texture is 4%, and the average grain size is 140 µm

[0156] When the mass content of silicon in the ultra-thin strip silicon steel prepared in this comparative example is 3.6%, the magnetic induction intensity B in the rolling direction 8 = 1.44 T, P 17 / 50 = 2.48 W / kg; the magnetic induction intensity B in the transverse direction 8 = 1.41 T, P 17 / 50 = 2.63 W / kg.

[0157] Compared with Comparative Example 2, in Example 2, the three-rolling process is adopted to control the texture of the ultra-thin strip. After long-time high-temperature annealing, the content of the cube texture in the obtained ultra-thin strip is 88%, while in Comparative Example 2, the two-rolling process and high-temperature annealing are adopted, and the content of the cube texture in the obtained ultra-thin strip is 4%. The ultra-thin strip in Example 2 has excellent magnetic properties. The B in the rolling direction 8 = 1.86 T, P 17 / 50=0.78W / kg; while the ultra-thin strip in Comparative Example 2 has very poor magnetic properties, and the magnetic induction intensity B in the rolling direction is 8 =1.44T,P 17 / 50 =2.48W / kg.

[0158] The above scheme, the present invention proposes an ultra-thin strip dual-oriented silicon steel and a preparation method, which can solve many technical problems existing in the preparation process of oriented silicon steel ultra-thin strip, thereby reducing production costs and improving economic benefits.

[0159] The present invention uses industrial pure iron and pure silicon as raw materials to prepare ultra-thin strip dual-oriented silicon steel without adding any inhibitors and rare earth elements, and the alloy composition of high silicon steel is slightly changed. Ultra-thin strip oriented silicon steel with a thickness of ≤0.1mm is prepared. The process flow is short, the efficiency is high, the raw materials are easy to obtain, and the cost advantage of industrialization is very obvious.

[0160] The present invention obtains a strong Goss texture ({110} <001> ) and a stronger λ texture ( <001> / / ND), by controlling the rolling reduction rate of the three cold rolling processes and the annealing temperature and time of the three annealing processes, the strong Goss texture and λ texture can be well inherited by the organization, and the cubic grains can swallow up the grains of other orientations to obtain a single strong cubic texture, which synergistically improves the magnetic properties in the rolling direction and the transverse direction, and increases the application range of silicon steel thin strips.

[0161] After the third rolling and primary recrystallization of the present invention, the primary recrystallized grains of the ultra-thin strip are mainly strong Goss and cubic textures, and the grain size is 30-80 μm; after high temperature annealing, the grain size is 1-8 mm

[0162] When the mass content of silicon in the ultra-thin strip bi-oriented silicon steel of the present invention is 3%, the magnetic induction intensity B in the rolling direction is 8 ≥1.82T, iron loss P 17 / 50 ≤0.8W / kg; transverse magnetic induction intensity B 8 ≥1.79T, iron loss P 17 / 50 ≤0.85W / kg; iron loss in rolling direction and transverse direction P 15 / 400 ≤17W / kg;

[0163] When the mass content of silicon is 3.5%, the magnetic induction intensity B in the rolling direction is 8 ≥1.80T, P 17 / 50 ≤0.75W / kg; transverse magnetic induction intensity B 8 ≥1.77T, P 17 / 50 ≤0.8W / kg; iron loss in rolling direction and transverse direction P 15 / 400 ≤16W / kg;

[0164] When the mass content of silicon is 4.5%, the magnetic induction intensity B in the rolling direction 8 ≥1.75T, P 17 / 50 ≤0.7W / kg; the magnetic induction intensity B in the transverse direction 8 ≥1.72T, P 17 / 50 ≤0.75W / kg; the iron loss P in the rolling direction and the transverse direction 15 / 400 ≤14W / kg.

[0165] In summary, compared with other traditional methods, the method of the present invention obtains an ultra-thin double-oriented silicon steel with excellent magnetic properties by means of component selection, controlling the hot rolling process to obtain a strong Goss texture, and adopting a three-time cold rolling process and a three-time annealing process to regulate the orientation in the silicon steel; it can synergistically improve the magnetic properties in the rolling direction and the transverse direction of the ultra-thin strip of the silicon steel, with high resource utilization rate, short process, high efficiency, and is conducive to large-scale industrial production and promotion.

[0166] It should be understood that the term "and / or" in this article is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Among them, A and B can be singular or plural. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after, but it may also represent an "and / or" relationship, which can be specifically understood with reference to the context before and after.

[0167] In the present invention, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or its similar expression refers to any combination of these items, including any combination of single item (s) or plural item (s). For example, at least one of a, b, or c can represent: a, b, c, a - b, a - c, b - c, or a - b - c, where a, b, and c can be single or multiple.

[0168] It should be understood that in various embodiments of the present invention, the magnitude of the sequence numbers of the above processes does not mean the sequence of execution. The execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0169] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An ultra-thin strip bi-oriented silicon steel, characterized in that: The thickness of the ultra-thin strip bi-oriented silicon steel is 0.03-0.10 mm, and the chemical composition is as follows by mass percentage: Si=2.7-5.0%, C≤0.006%, S≤0.008%, Mn≤0.01%, acid-soluble aluminum Als≤0.008%, P≤0.008%, N≤0.008%, Cu≤0.008%, and the balance is iron and unavoidable inclusions; wherein the lower limit of the aforementioned elements cannot be 0; The preparation method of the ultra-thin strip dual-oriented silicon steel comprises the following steps: S1. Smelting: pure silicon and industrial pure iron are mixed according to the composition ratio, melted and refined in a vacuum induction furnace, and cast to obtain an ingot; S2, cogging: Cogging the S1 ingot of required quality to obtain a rectangular billet; S3, hot rolling: after the rectangular billet in S2 is charged into a furnace at room temperature, it is heated and hot rolled in multiple passes to obtain a hot-rolled plate; S4, primary cold rolling: the S3 hot-rolled sheet is pickled, and then subjected to multiple cold rolling passes to obtain a primary cold-rolled sheet; S5, primary intermediate annealing: performing a primary intermediate annealing on the primary cold rolled sheet in S4 to obtain a primary annealed cold rolled sheet; S6, secondary cold rolling: the S5 primary annealing cold rolled sheet is subjected to multiple cold rolling passes to obtain a secondary cold rolled sheet; S7, secondary intermediate annealing: performing secondary intermediate annealing on the S6 secondary cold rolled sheet to obtain a secondary annealed cold rolled sheet; S8, three-pass cold rolling: the S7 double annealed cold-rolled sheet is subjected to multiple cold rollings to obtain a three-pass cold-rolled sheet; S9, high temperature annealing: The S8 three-time cold-rolled sheet is subjected to high temperature annealing in a weakly oxidizing atmosphere to obtain an ultra-thin strip of bi-oriented silicon steel.

2. The ultra-thin strip bi-oriented silicon steel according to claim 1, characterized in that: The content of cubic texture in the ultra-thin strip bi-oriented silicon steel is 85% or more, and the grain size is 1-8 mm.

3. The ultra-thin strip bi-oriented silicon steel according to claim 2, characterized in that: When the mass content of silicon in the ultra-thin strip bi-oriented silicon steel is 3%, the magnetic induction intensity B8 in the rolling direction is ≥1.82T, and the iron loss P 17 / 50 ≤0.8W / kg; transverse magnetic induction intensity B8≥1.79T, iron loss P 17 / 50 ≤0.85W / kg; iron loss in rolling direction and transverse direction P 15 / 400 ≤17W / kg; When the mass content of silicon is 3.5%, the magnetic induction intensity in the rolling direction B8≥1.80T, P 17 / 50 ≤0.75W / kg; transverse magnetic induction intensity B8≥1.77T, P 17 / 50 ≤0.8W / kg; iron loss in rolling direction and transverse direction P 15 / 400 ≤16W / kg; When the mass content of silicon is 4.5%, the magnetic induction intensity in the rolling direction B8≥1.75T, P 17 / 50 ≤0.7W / kg; transverse magnetic induction intensity B8≥1.72T, P 17 / 50 ≤0.75W / kg; iron loss in rolling direction and transverse direction P 15 / 400 ≤14W / kg.

4. A method for preparing ultra-thin strip bi-oriented silicon steel according to claim 1, characterized in that: The preparation method of the ultra-thin strip dual-oriented silicon steel comprises the following steps: S1. Smelting: pure silicon and industrial pure iron are mixed according to the composition ratio, melted and refined in a vacuum induction furnace, and cast to obtain an ingot; S2, cogging: Cogging the S1 ingot of required quality to obtain a rectangular billet; S3, hot rolling: after the rectangular billet in S2 is charged into a furnace at room temperature, it is heated and hot rolled in multiple passes to obtain a hot-rolled plate; S4, primary cold rolling: the S3 hot-rolled sheet is pickled, and then subjected to multiple cold rolling passes to obtain a primary cold-rolled sheet; S5, primary intermediate annealing: performing a primary intermediate annealing on the primary cold rolled sheet in S4 to obtain a primary annealed cold rolled sheet; S6, secondary cold rolling: the S5 primary annealing cold rolled sheet is subjected to multiple cold rolling passes to obtain a secondary cold rolled sheet; S7, secondary intermediate annealing: performing secondary intermediate annealing on the S6 secondary cold rolled sheet to obtain a secondary annealed cold rolled sheet; S8, three-pass cold rolling: the S7 double annealed cold-rolled sheet is subjected to multiple cold rollings to obtain a three-pass cold-rolled sheet; S9, high temperature annealing: The S8 three-time cold-rolled sheet is subjected to high temperature annealing in a weakly oxidizing atmosphere to obtain an ultra-thin strip of bi-oriented silicon steel.

5. The method for preparing ultra-thin strip bi-oriented silicon steel according to claim 4, characterized in that: In S2, the blank is forged by mechanical free forging, using an air hammer at 800-1100°C, and after multiple upsetting and drawing, a rectangular blank is obtained, or a rectangular blank is obtained by blanking with a rough rolling mill.

6. The method for preparing ultra-thin strip bi-oriented silicon steel according to claim 4, characterized in that: The hot rolling temperature in S3 is 850-1050°C, the heating rate is 10-800°C / min, the holding time after heating to the aforementioned temperature is 5-30min, three hot rolling passes are adopted, and the steel is returned to the furnace for holding for 5-20min between passes; the grains of the hot rolled plate are equiaxed grains, the grain size is 200-800μm, and the thickness of the hot rolled plate is 1.4-2.6mm.

7. The method for preparing ultra-thin strip bi-oriented silicon steel according to claim 4, characterized in that: The temperature of the multiple cold rolling in S4 is 10-400°C, the heating rate is 10-800°C / min, the holding time after heating to the above temperature is 3-30min, and the furnace is returned to the furnace for 3-20min between passes; the thickness of the single cold rolled plate is 0.4-0.8mm.

8. The method for preparing ultra-thin strip bi-oriented silicon steel according to claim 4, characterized in that: The temperatures of the primary intermediate annealing and the secondary intermediate annealing corresponding to S5 and S7 are both 950-1200°C, the heating rates are both 10-800°C / min, and the holding times are both 1-30min.

9. The method for preparing ultra-thin strip bi-oriented silicon steel according to claim 4, characterized in that: The reduction ratios of the secondary cold rolling and tertiary cold rolling corresponding to S6 and S8 are both 55%-75%, and the reduction ratio of the last pass of the secondary cold rolling is not more than 10%.

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