A high-plasticity isotropic magnesium alloy sheet and preparation method thereof

Abstract

The present invention relates to a high-plasticity isotropic magnesium alloy sheet and a preparation method thereof. The rolling direction of a hot-rolled sheet of a Mg-Zn-RE series or Mg-Zn-Ca series magnesium alloy is taken as a 0° reference, and a series of sliced ​​thin plates S1, S2, ... Sn are cut at intervals of 5-90°; the surface of the sliced ​​thin plates is mechanically polished / pickled to remove rust, cleaned and degreased, and then the sliced ​​thin plates are stacked in sequence, and the stacked sheet heads and tails are bundled with metal wires; then warm rolling deformation is performed at 150-275°C, the deformation amount of each pass is 20-70%, and no insulation or annealing treatment is performed between passes; then cold rolling deformation is performed at 20-50°C, the deformation amount of each pass is 5-10%; and finally annealing heat treatment is performed at 300-400°C for 30min-2h. The sheet prepared by the present invention has the characteristics of isotropic mechanical properties, high plasticity and weak texture, the production process is simple and efficient, the degree of automation is high, the mechanical properties are stable, and magnesium alloy coils of different thicknesses, widths and large sizes can be prepared.

Description

Technical Field

[0001] The invention belongs to the technical field of metal material preparation, and in particular relates to a high-plasticity isotropic magnesium alloy plate and a preparation method thereof. Background Art

[0002] As a green engineering material in the 21st century, magnesium alloy materials have a series of advantages such as light weight, high specific strength, and good electromagnetic shielding performance. They have received more and more attention in aerospace, transportation, and 3C communication electronic products. However, since magnesium alloys belong to the HCP crystal structure, they have low symmetry and large anisotropy of mechanical properties. For rolled plates, the tensile yield strength and elongation along the rolling direction and transverse direction are very different. Taking the Mg-Zn-Ce alloy (ZEK100) that has been studied more as an example, the room temperature tensile yield strength and elongation of its conventional rolled plates are approximately 175MPa / 25% and 120MPa / 35% along the rolling direction and transverse direction of the plate, respectively. The room temperature tensile yield strength and elongation of the rare earth magnesium alloy Mg-2Zn-0.8Gd alloy rolled plate are approximately 120MPa / 36% and 80MPa / 48% along the rolling direction and transverse direction of the plate, respectively. The anisotropy of the above-mentioned typical rare earth magnesium alloys may lead to uneven yielding during subsequent service or obvious earing during the stamping process, resulting in material waste and increased cutting process.

[0003] Studies have shown that the high room temperature plasticity of rare earth magnesium alloys is mainly caused by the rare earth texture formed by the rolled plate, which is deflected transversely during the rolling of the plate. Under the condition of rare earth texture, the basal slip and tensile twinning in the transverse direction of the plate are easier to start, which leads to low yield strength in this direction, high work hardening ability, and high room temperature tensile elongation, while the yield strength is high and the elongation is low in the rolling direction. Studies have found that the cross-rolling process of changing the rolling direction and the transverse direction in each pass can suppress the anisotropy of the above-mentioned mechanical properties, but the actual preparation process requires changing the rolling direction and the transverse direction of the plate in each pass, which is cumbersome and inefficient. It is also limited by the width of the rolling mill and can only produce single-piece magnesium alloy plates, and cannot produce large-size coils, so its practical application is limited. Therefore, the development of high-plasticity isotropic magnesium alloy plates and their preparation methods have important engineering value for expanding the application of magnesium alloys. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0006] The purpose of the present invention is to provide a high-plasticity isotropic magnesium alloy plate and a preparation method thereof. The present invention uses an innovative rolling process and a superimposed warm rolling technology to regulate the thermal deformation and recrystallization behavior of grains with different orientations. The superimposed warm rolling technology of thin plates sliced ​​at different angles is used to regulate the distribution of texture in all directions of the rolled plate and refine the grain size of the magnesium alloy, thereby obtaining isotropic mechanical properties and high plasticity at room temperature.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a high-strength and high-formability magnesium alloy sheet and a preparation method thereof, comprising:

[0008] The high-plasticity isotropic magnesium alloy sheet and the preparation method thereof are characterized in that: a) the room temperature tensile yield strength of the high-plasticity isotropic magnesium alloy sheet has a yield strength difference ratio (σ smax -σ smin ) / σ smax less than 5%, room temperature tensile plasticity greater than 30%, and base surface pole figure texture strength peak value less than 4.5; b) the preparation of the magnesium alloy sheet comprises the following steps:

[0009] 1) Ingot preparation;

[0010] 2) Solution treatment and hot rolling deformation;

[0011] 3) Warm rolling and annealing: the plate treated in step 2) is cut into a series of sliced ​​thin plates S1, S2, ... Sn at intervals of 5-90 degrees with the rolling direction as 0 degrees; the upper and lower surfaces and the sides of the sliced ​​thin plates are polished to remove the oxide scale, and the sliced ​​thin plates are stacked in sequence, and the stacked plates are bundled at the head and tail with metal wires; then, warm rolling deformation is performed at 150-275°C, with a deformation amount of 20-70% per pass, and no insulation or annealing treatment is performed between passes; then, cold rolling deformation is performed at 20-50°C, with a deformation amount of 5-10% per pass; finally, annealing heat treatment is performed at 300-400°C for 30 minutes to 2 hours.

[0012] The high-plasticity isotropic magnesium alloy sheet and preparation method thereof are characterized in that the magnesium alloy is a low rare earth content Mg-Zn-RE series, RE is Gd, Ce or Y, and the RE content is less than 1% (wt.%); or a Mg-Zn-Ca series magnesium alloy.

[0013] The high-plasticity isotropic magnesium alloy sheet and its preparation method are characterized in that: the ingot is prepared by a metal mold, a sand mold or a semi-continuous casting method; a square billet of a certain size is cut from the ingot;

[0014] The high-plasticity isotropic magnesium alloy sheet and its preparation method are characterized in that: step 2) the solution treatment is for square billets to be solution treated at 400-480°C for 8-12h to remove oxide scale and chamfer; the hot rolling deformation, the rolling temperature is 300-450°C, the rolling deformation amount of each pass is 15-50%, and the insulation between passes is 15-30min; the total deformation amount of the rolling process is 80-90%; the hot-rolled sheet is annealed at 325-400°C for 0.5-1.5h.

[0015] The high-plasticity isotropic magnesium alloy sheet and the preparation method thereof are characterized in that the thickness of the hot-rolled sheet sliced ​​thin plate is 1-5 mm.

[0016] The high-plasticity isotropic magnesium alloy sheet and the preparation method thereof are characterized in that all the stacked sliced ​​thin plates are cut counterclockwise or clockwise, and the angle with the rolling direction 0° reference must cover the entire 0-180° range.

[0017] The high-plasticity isotropic magnesium alloy sheet and the preparation method thereof are characterized in that the surfaces of all the stacked sliced ​​thin plates are mechanically polished / pickled to remove rust, cleaned and degreased, and then stacked together and subjected to overlapping rolling treatment.

[0018] The high-plasticity isotropic magnesium alloy sheet and its preparation method are characterized in that: in the cold rolling deformation, the cumulative cold rolling deformation is 10-20%; the cold rolling deformation direction is consistent with the superimposed warm rolling direction or is 180°.

[0019] The design principle of the present invention is as follows:

[0020] Existing Mg-Zn-RE / Ca magnesium alloys will form a rare earth texture that deflects along the rolling transverse direction after conventional rolling deformation. Since this texture is conducive to the initiation of basal slip and tensile twinning in the magnesium alloy, the room temperature tensile plasticity of such magnesium alloys is improved. However, the transversely deflected rare earth texture also leads to a large anisotropy of the mechanical properties of the above magnesium alloys, which is prone to uneven yielding and punching earing, making it difficult to meet engineering requirements. The present invention achieves the purpose of regulating texture distribution by cutting slices of thin plates that deviate from the original rolling direction at different angles from the hot-rolled plate and performing overlapping warm rolling. Studies have shown that the texture of rare earth magnesium alloys is controlled by deformation and recrystallization processes. Deformed structures and local recrystallized structures will be produced during warm rolling. When plates in different directions are superimposed, the deformation mechanisms initiated during warm rolling are also different due to the different forces and stress-strain states of the plate slices in different directions, thereby obtaining deformation structures and recrystallized structures with different characteristics. Cold rolling deformation can further increase the deformation energy storage inside the grain structure with different orientation distributions, so that the mutual influence of the deformation texture and recrystallization texture of the plate in the final annealing and recrystallization process leads to a more discrete texture of the final plate and uniform distribution in different directions of the plate, avoiding the orientation preference in a certain direction under conventional process conditions. In addition, superimposed warm rolling and cold rolling processes at a lower temperature can achieve higher Z parameters and accumulated strains, and smaller grains can be obtained in magnesium alloys, thereby improving the plasticity and yield strength of the plate.

[0021] The technical effects of the present invention or the advantages of the present invention compared with the prior art shall be explained and supported by specific data and described in a specific and realistic manner.

[0022] (1) The present invention provides a method for preparing a high-plasticity isotropic magnesium alloy sheet. The sheet slices can be efficiently produced and prepared after being stacked, with a high degree of automation. The cross rolling with frequent changes in rolling direction is more concise and efficient, and large-sized magnesium alloy coils can be prepared; the sheet has good rolling deformation ability, and there is little or no edge cracking during warm or cold rolling of thin sheets, eliminating the need for trimming and other processes; the prepared magnesium alloy sheet has isotropic mechanical properties and high yield strength, and the sheet has stable mechanical properties during coiling and uncoiling.

[0023] (2) The magnesium alloy thin plate prepared by the combined warm rolling and cold rolling process of the present invention has a small and uniform grain size, and the strength and toughness of the plate are better than those of the traditional cross rolling process.

[0024] (3) Compared with cross-rolling and other patents, the present invention can produce magnesium alloy thin plates with adjustable width, thickness and length, and isotropic mechanical properties, which can meet the requirements of continuous stamping production lines for the specifications and performance of magnesium alloy plates. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0026] Figure 1 The invention discloses a method for sampling and stacking a high-plasticity isotropic magnesium alloy.

[0027] Figure 2 This is a microstructure photograph of the plate prepared in Example 1 of the present invention.

[0028] Figure 3 This is the room temperature tensile mechanical property curve of the plate prepared in Example 4 of the present invention. As can be seen from the figure, the yield strength and elongation of the plate are basically close, showing isotropy of mechanical properties. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0030] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0031] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0032] The following is a detailed description in conjunction with specific implementation methods.

[0033] Example 1

[0034] (1) A Mg-1.9Zn-0.8Gd alloy with a chemical composition was prepared by a metal mold casting method. A square billet of a certain thickness was cut from the ingot.

[0035] (2) The square billet is solution treated at 450°C for 10 hours to remove the oxide scale and chamfer; hot rolling deformation is performed, the rolling temperature is 300-420°C, the deformation amount of each pass is 20-40%, and the heat preservation between passes is 15-30 minutes; the total deformation amount of the rolling process is 80-90%; the hot-rolled plate is annealed at 350°C for 1 hour.

[0036] (3) A series of sliced ​​thin plates S1, S2, ..., S13 are cut from the above-mentioned plate with the rolling direction as 0° as the reference and at intervals of 15°; the thickness of the sliced ​​thin plates is 1 mm; the surfaces of the above-mentioned sliced ​​thin plates are mechanically polished / pickled to remove rust, cleaned and degreased, and then the sliced ​​thin plates are stacked in order, and the heads and tails of the stacked plates are bundled with metal wires; then, warm rolling is performed at 200°C, and the deformation of the first three passes is 40-70%. The rolling is continuous without insulation or annealing between passes, and the subsequent rolling deformation is 20-40%; when the plate temperature drops to 20-50°C, cold rolling is performed, and the deformation of each pass is 5-10%, and the cumulative cold rolling deformation is 15%; after rolling, annealing heat treatment is performed at 300°C for 2h.

[0037] (4) The room temperature tensile yield strength and elongation of the prepared magnesium alloy sheet are 180MPa / 35%, 175MPa / 36% and 178MPa / 34% along the rolling direction, transverse direction and 45° respectively according to national standards; the texture peak strength of the (0002) basal plane pole figure is 3.2mrd. The mechanical properties of the sheet are isotropic.

[0038] Example 2

[0039] (1) A Mg-1.9Zn-0.8Gd alloy with a chemical composition was prepared by a metal mold casting method. A square billet of a certain thickness was cut from the ingot.

[0040] (2) The square billet is solution treated at 420°C for 12 hours to remove the oxide scale and chamfer; hot rolling deformation is performed, the rolling temperature is 300-420°C, the deformation amount of each pass is 20-40%, and the heat preservation between passes is 15-30 minutes; the total deformation amount of the rolling process is 80-90%; the hot-rolled plate is annealed at 350°C for 1 hour.

[0041] (3) A series of sliced ​​thin plates S1, S2, and S3 are cut from the above-mentioned plate with the rolling direction as 0° as the reference and at intervals of 90°; the thickness of the sliced ​​thin plates is 5 mm; the surfaces of the above-mentioned sliced ​​thin plates are mechanically polished / pickled to remove rust, cleaned and degreased, and then the sliced ​​thin plates are stacked in order, and the heads and tails of the stacked plates are bundled with metal wires; then, warm rolling is performed at 275°C, and the deformation of the first three passes is 30-60%. The rolling is continuous, and no insulation or annealing treatment is performed between passes, and the subsequent rolling deformation is 20-30%; when the plate temperature drops to 20-50°C, cold rolling is performed, and the deformation of each pass is 5-10%, and the cumulative cold rolling deformation is 20%; after rolling, annealing heat treatment is performed at 350°C for 1.5 hours.

[0042] (4) The room temperature tensile yield strength and elongation of the prepared magnesium alloy sheet are 185MPa / 33%, 188MPa / 33% and 184MPa / 32% along the rolling direction, transverse direction and 45° respectively according to national standards; the texture peak strength of the (0002) basal plane pole figure is 3.9mrd. The mechanical properties of the sheet are isotropic.

[0043] Example 3

[0044] (1) A Mg-1.5Zn-0.5Ce alloy with a chemical composition is prepared by a metal mold casting method. A square billet of a certain thickness is cut from the ingot.

[0045] (2) The square billet is solution treated at 410°C for 10 hours to remove the oxide scale and chamfer; hot rolling deformation is performed, the rolling temperature is 300-410°C, the deformation amount of each pass is 20-35%, and the heat preservation between passes is 15-30 minutes; the total deformation amount of the rolling process is 80-90%; the hot-rolled plate is annealed at 350°C for 1 hour.

[0046] (3) A series of sliced ​​thin plates S1, S2, ..., S7 are cut from the above-mentioned plate at intervals of 30° with the rolling direction as the 0° reference; the thickness of the sliced ​​thin plates is 1.5 mm; the surfaces of the above-mentioned sliced ​​thin plates are mechanically polished / pickled to remove rust, cleaned and degreased, and then the sliced ​​thin plates are stacked in order, and the heads and tails of the stacked plates are bundled with metal wires; then, warm rolling is performed at 150°C, and the deformation of the first three passes is 30-50%, and continuous rolling is performed without insulation or annealing between passes, and the subsequent rolling deformation is 20-30%; when the plate temperature drops to 20-50°C, cold rolling is performed, and the deformation of each pass is 5-10%, and the cumulative cold rolling deformation is 10%; after rolling, annealing heat treatment is performed at 325°C for 1 hour.

[0047] (4) The room temperature tensile yield strength and elongation of the prepared magnesium alloy sheet are 159MPa / 36%, 162MPa / 36% and 163MPa / 34% along the rolling direction, transverse direction and 45° respectively according to national standards; the texture peak strength of the (0002) basal plane pole figure is 2.8mrd. The mechanical properties of the sheet are isotropic.

[0048] Example 4

[0049] (1) A Mg-0.8Zn-0.15Ca alloy with a chemical composition was prepared by a metal mold casting method. A square billet of a certain thickness was cut from the ingot.

[0050] (2) The square billet is solution treated at 400°C for 8 hours to remove the oxide scale and chamfer; hot rolling deformation is performed, the rolling temperature is 300-400°C, the deformation amount of each rolling pass is 15-40%, and the heat preservation between passes is 15-30 minutes; the total deformation amount of the rolling process is 80-90%; the hot-rolled plate is annealed at 325°C for 1.5 hours.

[0051] (3) A series of sliced ​​thin plates S1, S2, ... S5 are cut from the above-mentioned plate at intervals of 45° with the rolling direction as the 0° reference; the thickness of the sliced ​​thin plates is 1.5 mm; the surfaces of the above-mentioned sliced ​​thin plates are mechanically polished / pickled to remove rust, cleaned and degreased, and then the sliced ​​thin plates are stacked in order, and the heads and tails of the stacked plates are bundled with metal wires; then warm rolling is performed at 200°C, and the deformation of the first three passes is 30-50%, and continuous rolling is performed without insulation or annealing between passes, and the subsequent rolling deformation is 20-30%; when the plate temperature drops to 20-50°C, cold rolling is performed, and the deformation of each pass is 5-10%, and the cumulative cold rolling deformation is 15%; after rolling, annealing heat treatment is performed at 400°C for 0.5h.

[0052] (4) The room temperature tensile yield strength and elongation of the prepared magnesium alloy sheet are 154MPa / 33%, 149MPa / 34% and 148MPa / 34% respectively along the rolling direction, transverse direction and 45° according to national standards; the texture peak strength of the (0002) basal plane pole figure is 3.4. The mechanical properties of the sheet are isotropic.

[0053] Example 5

[0054] (1) A Mg-1.3Zn-0.6Y alloy with a chemical composition is prepared by a metal mold casting method. A square billet of a certain thickness is cut from the ingot.

[0055] (2) The square billet is solution treated at 420°C for 8 hours to remove the oxide scale and chamfer; hot rolling deformation is performed, the rolling temperature is 300-420°C, the deformation amount of each pass is 20-35%, and the heat preservation between passes is 15-30 minutes; the total deformation amount of the rolling process is 80-90%; the hot-rolled plate is annealed at 400°C for 0.5h.

[0056] (3) A series of sliced ​​thin plates S1, S2, ... S5 are cut from the above-mentioned plate with the rolling direction as 0° as the reference and at intervals of 45°; the thickness of the sliced ​​thin plates is 1.0 mm; the surfaces of the above-mentioned sliced ​​thin plates are mechanically polished / pickled to remove rust, cleaned and degreased, and then the sliced ​​thin plates are stacked in order, and the heads and tails of the stacked plates are bundled with metal wires; then, warm rolling is performed at 250°C, and the deformation of the first three passes is 30-60%. The rolling is continuous without insulation or annealing between passes, and the subsequent rolling deformation is 20-30%; when the plate temperature drops to 20-50°C, cold rolling is performed, and the deformation of each pass is 5-10%, and the cumulative cold rolling deformation is 20%; after rolling, annealing heat treatment is performed at 400°C for 0.5h.

[0057] (4) The room temperature tensile yield strength and elongation of the prepared magnesium alloy sheet are 145MPa / 35%, 144MPa / 37% and 138MPa / 34% along the rolling direction, transverse direction and 45° respectively according to national standards; the texture peak strength of the (0002) basal plane pole figure is 3.7. The mechanical properties of the sheet are isotropic.

[0058] Comparative Example 1

[0059] (1) A Mg-1.9Zn-0.8Gd alloy with a chemical composition was prepared by a metal mold casting method. A square billet of a certain thickness was cut from the ingot.

[0060] (2) The square billet is solution treated at 450°C for 10 hours to remove the oxide scale and chamfer; hot rolling deformation is performed, the rolling temperature is 300-420°C, the deformation amount of each pass is 20-40%, and the heat preservation between passes is 15-30 minutes; the total deformation amount of the rolling process is 80-90%; the hot-rolled plate is annealed at 350°C for 1 hour.

[0061] (3) From the above-mentioned plate, three parallel sliced ​​thin plates S1, S2, and S3 are cut along the rolling direction; the thickness of the sliced ​​thin plates is 2 mm; the surfaces of the above-mentioned sliced ​​thin plates are mechanically polished / pickled to remove rust, cleaned and degreased, and then the sliced ​​thin plates are stacked in order, and the heads and tails of the stacked plates are bundled with metal wires; then, warm rolling is performed at 250°C, and the deformation of the first three passes is 30-50%. The rolling is continuous, and no insulation or annealing treatment is performed between passes. The subsequent rolling deformation is 20-30%; when the plate temperature drops to 20-50°C, cold rolling is performed, and the deformation of each pass is 5-10%, and the cumulative cold rolling deformation is 20%; after rolling, annealing heat treatment is performed at 350°C for 1 hour.

[0062] (4) The room temperature tensile yield strength and elongation of the prepared magnesium alloy sheet are 142MPa / 30%, 96MPa / 45% and 101MPa / 32% along the rolling direction, transverse direction and 45° respectively according to national standards; the texture peak strength of the (0002) basal plane pole figure is 4.8. The sheet exhibits obvious anisotropy of mechanical properties.

[0063] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a high-plasticity isotropic magnesium alloy sheet, characterized in that: a) the magnesium alloy is a low rare earth content Mg-Zn-RE or Mg-Zn-Ca magnesium alloy, wherein RE is Gd, Ce or Y, and the RE content is less than 1% (wt.%); b) the high plasticity isotropic magnesium alloy sheet has a room temperature tensile yield strength difference ratio (σ) along the rolling direction, transverse direction and 45° direction. s max -σ s min ) / σ s max Less than 5%, where σ s max Represents the maximum value of the yield strength along the rolling direction, transverse direction and 45° direction, σ s min represents the minimum value of the yield strength along the rolling direction, transverse direction and 45° direction; the room temperature tensile plasticity is greater than 30%, and the peak value of the base surface pole figure texture strength is less than 4.5; c) the preparation of the magnesium alloy sheet comprises the following steps: 1) Ingot preparation: using metal mold, sand mold or semi-continuous casting method; cutting square billets of a certain size from the ingot; 2) Solution treatment and hot rolling deformation: the square billet is solution treated at 400-480℃ for 8-12h to remove the oxide scale and chamfer; the hot rolling deformation, the rolling temperature is 300-450℃, the deformation of each pass is 15-50%, and the heat preservation between passes is 15-30min; the total deformation of the rolling process is 80-90%; the hot-rolled plate is annealed at 325-400℃ for 0.5-1.5h; 3) Warm rolling and annealing treatment: for the plate treated in step 2), a series of sliced ​​thin plates S1, S2, ... Sn with a thickness of 1-5 mm are cut counterclockwise or clockwise at intervals of 5-90 degrees with the rolling direction as the 0 degree reference, and the angle between the sliced ​​thin plates and the rolling direction 0 degree reference covers the entire range of 0-180 degrees; the surfaces of the sliced ​​thin plates are mechanically polished / pickled to remove rust, cleaned and degreased, and then the sliced ​​thin plates are stacked in sequence, and the stacked plates are bundled with metal wires; then, warm rolling deformation is performed at 150-275°C, with a deformation amount of 20-70% per pass, and no insulation or annealing treatment is performed between passes; then, cold rolling deformation is performed at 20-50°C, with a deformation amount of 5-10% per pass, and the cumulative cold rolling deformation amount is 10-20%; finally, annealing heat treatment is performed at 300-400°C for 30min-2h.

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