Zirconium alloy plate with weak anisotropy and excellent formability and preparation method thereof

Abstract

The invention relates to the field of materials, and discloses a zirconium alloy plate with weak anisotropy and excellent formability and a preparation method thereof.The preparation method comprises the steps that a zirconium alloy forging stock is subjected to hot rolling, first annealing, cold rolling and second annealing in sequence, hot rolling comprises at least two heating number rolling, the last heating number rolling of hot rolling is cross rolling, and the second heating number rolling of cold rolling is cross rolling; rolling of other heating numbers is one-way rolling. One-way hot rolling and cross hot rolling are adopted, two times of annealing are cooperated, cold rolling is carried out between the two times of annealing, and the microstructure is fully refined through hot rolling and cold rolling, so that the prepared plate has high-strength and high-plasticity mechanical properties, meanwhile, the anisotropy is low, and the forming performance is quite excellent; the problem of obvious anisotropy in the existing zirconium alloy plate is solved without improving the existing rolling mill equipment, and the use performance of the plate is improved.

Description

Technical Field

[0001] This invention relates to the field of materials, and more specifically to a zirconium alloy sheet with weak anisotropy and excellent formability, and a method for preparing the same. Background Technology

[0002] R60702 (Zr-3) alloy, due to its suitable strength-plasticity balance and corrosion resistance, has wide applications in petrochemical, pressure vessel, aerospace structural materials, and metallurgical industries. However, its hexagonal close-packed crystal structure leads to preferred grain orientation during deformation, especially after cold rolling and annealing, resulting in strong texture. This strong texture causes anisotropic mechanical properties in the sheet metal, making it prone to cracking along specific orientations during stamping, limiting its machinability and hindering the further development and application of zirconium and zirconium alloys. Currently, the mechanical properties of zirconium alloy sheets generally meet industry or standard requirements, but the significant anisotropy of these sheets urgently needs to be addressed. Therefore, developing R60702 industrial-grade zirconium alloy sheets with excellent machinability while ensuring or further improving mechanical properties is crucial for the application of zirconium and zirconium alloys in related fields. Summary of the Invention

[0003] The purpose of this invention is to overcome the problem of large anisotropy differences in existing zirconium alloy sheet processing technology, and to provide a zirconium alloy sheet with weak anisotropy and excellent formability, as well as a method for preparing the same. The zirconium alloy sheet prepared by this method has low transverse and longitudinal anisotropy and excellent uniformity of mechanical properties.

[0004] To achieve the above objectives, the first aspect of the present invention provides a method for preparing zirconium alloy sheet, wherein the method includes: hot rolling, first annealing, cold rolling and second annealing of a zirconium alloy forging billet in sequence, wherein the hot rolling includes at least two rolling passes, the last rolling pass of the hot rolling is cross rolling, and the other rolling passes are unidirectional rolling.

[0005] The second aspect of the present invention provides a zirconium alloy sheet prepared by the preparation method according to the first aspect of the present invention, wherein the difference between the transverse and longitudinal tensile strength of the prepared zirconium alloy sheet does not exceed 15 MPa, the difference between the transverse and longitudinal yield strength does not exceed 50 MPa, and the difference between the transverse and longitudinal elongation does not exceed 5%.

[0006] Through the above technical solution, the present invention employs unidirectional hot rolling and cross hot rolling, combined with two annealing processes, and cold rolling between the two annealing processes. The microstructure is fully refined through hot rolling and cold rolling, resulting in a sheet material with high strength and high plasticity while exhibiting low anisotropy. Compared with traditional processes, the problem of significant anisotropy in existing zirconium alloy sheets is solved without modifying existing rolling mill equipment, thus improving the performance of the sheet material.

[0007] The method provided by this invention is applicable to the preparation of all metal plates with close-packed hexagonal structures, and is especially suitable for the preparation of zirconium alloys and titanium alloys. The zirconium alloys can be R60700, R60702 and R60705, etc. Attached Figure Description

[0008] Figure 1 The microstructure of the plates prepared in Examples 1-4; Figure 2 These are pole figures of the plates prepared in Examples 1-4; Figure 3 The microstructure of the plates prepared in Examples 5-8; Figure 4 These are pole figures of the plates prepared in Examples 5-8; Figure 5 This is a schematic diagram showing the state of the plates prepared in Examples 4 and 7 after bending performance testing. Detailed Implementation

[0009] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0010] The terms “first”, “second”, etc. are used to distinguish similar objects, not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein. The objects distinguished by “first”, “second”, etc. are usually of the same class and the number of objects is not limited. For example, the first object can be one or more.

[0011] Furthermore, the term "and / or" in the specification and claims is used to describe the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0012] In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0013] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0014] In this application, a hexagonal close-packed crystal structure refers to a hexagonal crystal structure with 12 atoms at the vertices of the hexagonal cell, one atom at the center of each bottom face, and three coplanar atoms at half-maximum inside the cell, with an axial ratio of approximately 1.633. This includes zirconium alloys, titanium alloys, magnesium alloys, etc.

[0015] The basal plane B texture refers to the microscopic crystal arrangement pattern formed in the alloy material during hot working. In this application, it specifically refers to the texture where the (0002) crystal plane is parallel to the deformation plane.

[0016] Basal bimodal B texture refers to the texture of the (0002) crystal plane located between the parallel deformation plane and the perpendicular deformation plane.

[0017] The first aspect of the present invention provides a method for preparing zirconium alloy sheet, wherein the method includes: hot rolling, first annealing, cold rolling and second annealing of a zirconium alloy forging billet in sequence, wherein the hot rolling includes at least two rolling passes, the last rolling pass of the hot rolling is cross rolling, and the other rolling passes are unidirectional rolling.

[0018] The preparation steps of the zirconium alloy forging billet in this application include: performing three VAR melting processes on the zirconium alloy raw material to obtain an ingot, forging the ingot twice at a forging temperature of 900℃-1000℃, and air cooling to room temperature after forging to obtain the zirconium alloy forging billet.

[0019] This application does not have any special requirements for the cross rolling direction of the last hot rolling pass; as long as a certain degree of reversal is performed, it is acceptable.

[0020] Preferably, the final hot rolling step includes: first rolling along a first direction of the material to be rolled, and then rolling along a second direction of the material to be rolled, wherein the first direction is perpendicular to the second direction, and the deformation of the rolling along the second direction is 50-55%. Generally, the first direction is longitudinal, the second direction is transverse, and the deformation of the rolling along the second direction can be 50%, 51%, 52%, 53%, 54%, 55%, or any value between any two of these values.

[0021] Preferably, the hot rolling includes three rolling passes, and the deformation of each rolling pass tends to increase with the increase of the number of rolling passes.

[0022] Preferably, the total deformation of the first hot rolling pass is 50-70%, the total deformation of the second hot rolling pass is 70-80%, and the total deformation of the third hot rolling pass is 70-90%. The sequential increase in rolling deformation not only eliminates grain growth caused by the temperature difference between each hot rolling pass and effectively controls grain size, but also sufficiently refines the microstructure. The deformation of the first hot rolling pass can be 50%, 52%, 55%, 57%, 60%, 62%, 65%, 68%, 70%, or any value between any two of these values; the deformation of the second hot rolling pass can be 70%, 72%, 75%, 77%, 80%, or any value between any two of these values; the deformation of the third hot rolling pass can be 70%, 72%, 75%, 77%, 80%, 82%, 85%, 88%, 90%, or any value between any two of these values.

[0023] Preferably, the hot rolling temperature is 650-750℃. A suitable hot rolling temperature can ensure both a large amount of deformation and sufficient grain breakage. The hot rolling temperature can be 650℃, 670℃, 690℃, 710℃, 730℃, 750℃, or any value between any two of these.

[0024] Preferably, the total deformation of the cold rolling is 70-80%. Small deformation cannot sufficiently refine the grains, while excessively large deformation will result in poor sheet shape of the prepared material. The deformation of the cold rolling can be 70%, 72%, 74%, 76%, 78%, 80%, or any value between any two of these values.

[0025] Preferably, the cold rolling includes at least four rolling passes, and the deformation of each rolling pass increases with the number of rolling passes. This allows for sufficient grain refinement.

[0026] Preferably, the deformation of each pass of the cold rolling process is 5-25%.

[0027] Preferably, the deformation of each pass in the cold rolling process is 8-18%. The deformation of each pass in the cold rolling process can be 5%, 8%, 9%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 25%, or any value between any two of these values.

[0028] Preferably, the temperatures for the first and second annealing are independently set to 400-650℃, and the times are independently set to 30-50 min. Annealing temperature affects grain size and texture type; a suitable annealing temperature ensures both appropriate grain size and suitable texture strength. The first and second annealing temperatures can be independently set to 400℃, 420℃, 450℃, 480℃, 500℃, 520℃, 550℃, 580℃, 600℃, 620℃, 650℃, or any value between any two of these values, and the times can be independently set to 30 min, 35 min, 40 min, 45 min, 50 min, or any value between any two of these values.

[0029] Preferably, the cold rolling is unidirectional rolling, and the second annealing temperature is 590-610℃. When unidirectional cold rolling is used, combined with a specific second annealing temperature, the anisotropy of the resulting sheet material can be reduced, thus meeting processing requirements.

[0030] Preferably, the cold rolling is cross-rolling, and the temperature of the second annealing is 540-560℃. When cross-cold rolling is used, it is beneficial to further reduce the anisotropy of the sheet material, and a lower second annealing temperature can be used.

[0031] The second aspect of the present invention provides a zirconium alloy sheet prepared by the preparation method according to the first aspect of the present invention, wherein the difference between the transverse and longitudinal tensile strength of the zirconium alloy sheet does not exceed 15 MPa, the difference between the transverse and longitudinal yield strength does not exceed 50 MPa, and the difference between the transverse and longitudinal elongation does not exceed 5%.

[0032] Preferably, the difference between the transverse and transverse tensile strengths of the zirconium alloy sheet does not exceed 5 MPa, the difference between the transverse and longitudinal yield strengths does not exceed 5 MPa, and the difference between the transverse and longitudinal elongation does not exceed 1%.

[0033] Preferably, the strain hardening index of the zirconium alloy plate in the 45° direction is not less than 0.13, and its strain hardening index in both the T and L directions is not less than 0.12.

[0034] Preferably, the average value of the plastic strain ratio in the T-direction, the plastic strain ratio in the L-direction, and the plastic strain ratio in the 45° direction of the zirconium alloy plate is not less than 18.

[0035] This application achieves sufficient deformation in both the transverse and longitudinal directions of the sheet by implementing a large amount of rolling deformation and using cross rolling during the hot rolling stage. Furthermore, by combining the lower hot rolling temperature and control of rolling deformation, the deformed structure of the hot-rolled sheet can be fully refined. During cold rolling, either unidirectional rolling or cross rolling can be used. In particular, cross rolling can significantly regulate the microstructure of the material, control grain orientation, and improve the formability and mechanical properties of the sheet.

[0036] This application also provides a particularly preferred embodiment that enables the closely packed hexagonal zirconium alloy sheet to exhibit extremely weak anisotropy. The preparation method includes: hot rolling, first annealing, cold rolling, and second annealing of a zirconium alloy forging billet in sequence. The hot rolling includes three rolling passes, and the deformation of each rolling pass increases with the number of rolling passes. The first hot rolling pass is unidirectional rolling with a total deformation of 55-65%. The second hot rolling pass is unidirectional rolling with a total deformation of 73-78%. The third hot rolling pass is cross rolling with a total deformation of 75-85%. The final hot rolling step includes: first rolling along a first direction of the material to be rolled, and then rolling along a second direction of the material to be rolled, wherein the first direction is perpendicular to the second direction, and the deformation of the rolling along the second direction is 53-55%; The cold rolling is a cross rolling process with a total deformation of 70-80%. The cold rolling direction changes by 90° every two passes. The deformation of each pass of the cold rolling increases with the increase of the number of rolling passes.

[0037] The present invention will be described in detail below through examples. Unless otherwise specified, all reagents or instruments used in the following examples are commercially available conventional products. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply.

[0038] Microstructure was determined by metallographic microscopy; IPF plots and pole figures were characterized by EBSD experiments. Mechanical properties were tested in accordance with YS / T 753-2011.

[0039] Preparation Example 1 The R60702 zirconium alloy raw material was subjected to three VAR melting processes to obtain an ingot. The ingot was then forged twice at a forging temperature of 950℃. After forging, it was air-cooled to room temperature to obtain a zirconium alloy forging billet.

[0040] Example 1 Step 1: The R60702 zirconium alloy forging billet with specifications of 200mm×1250mm×1400mm is hot rolled three times. The total deformation of the first hot rolling is 60%, which is completed in three passes. The deformation amounts of each pass are 25%, 20%, and 33.3%, respectively. Unidirectional rolling is used, the rolling temperature is 750℃, and it is air-cooled to room temperature to obtain the first plate.

[0041] Step 2: The first sheet is rolled in a second pass with a total deformation of 75%, in four passes: 25%, 35%, 30%, and 27%, using unidirectional rolling at a rolling temperature of 650°C, and then air-cooled to room temperature to obtain the second sheet.

[0042] Step 3: The second plate is rolled for the third time with a total deformation of 80% at a rolling temperature of 650°C. The longitudinal deformation during rolling is 60% in four passes: 20%, 25%, 20%, and 16.7%. Then, the direction is reversed and the plate is widened by rolling in the transverse direction with a deformation of 50% in three passes: 25%, 20%, and 16.7%, to obtain the third plate.

[0043] Step 4: Perform a first annealing treatment on the third plate at a temperature of 550°C for 45 minutes to obtain the fourth plate.

[0044] Step 5: The fourth sheet is subjected to unidirectional cold rolling with a total deformation of 75%, which is completed in ten passes. The deformation of each pass is 8.75%, 9.3%, 9.6%, 10.4%, 11.2%, 12.2%, 13.4%, 15%, 16.3%, and 16.6%, respectively. After cold rolling, the fifth sheet is obtained.

[0045] Step 6: Perform a second annealing on the fifth plate at a temperature of 450°C for 30 minutes, and then air-cool it to room temperature to obtain a zirconium alloy plate.

[0046] Examples 2-4 The process was carried out in accordance with Example 1, with the only difference being that the second annealing temperatures in Examples 2-4 were 500°C, 550°C, and 600°C, respectively.

[0047] Example 5 Step one and step two are performed in the same manner as steps one and two in Example 1.

[0048] Step 3: Roll the second plate for the third time at a rolling temperature of 650℃. The longitudinal deformation during rolling is 60%, and it is rolled in four passes: 20%, 25%, 20%, and 16.7%. Then, it is rolled in the transverse direction to widen the plate, with a deformation of 55%, in three passes: 25%, 25%, and 18%, to obtain the third plate.

[0049] Step 4: Perform a first annealing treatment on the third plate at a temperature of 550°C for 45 minutes to obtain the fourth plate.

[0050] Step 5: The fourth sheet is subjected to cross-cold rolling with a total deformation of 75%, completed in ten passes, with a 90° reversal every two passes. The deformation of each pass is 8.75%, 9.3%, 9.6%, 10.4%, 11.2%, 12.2%, 13.4%, 15%, 16.2%, and 17%, respectively. After cold rolling, the fifth sheet is obtained.

[0051] Step six: Proceed as described in step six of Example 1.

[0052] Examples 6-8 The process was carried out in accordance with Example 5, with the only difference being that the second annealing temperatures in Examples 5-8 were 500°C, 550°C, and 600°C, respectively.

[0053] Taking the plates obtained in Examples 1-8 as examples, their microstructure IPF maps and pole figures were analyzed, and the results are as follows: Figure 1-4 As shown. Figure 1 The microstructures of the plates obtained in Examples 1-4 are shown. All of them were produced by unidirectional cold rolling, differing only in the second annealing temperature. Figure 1 (a) The second annealing temperature is 450℃. Figure 1 (b) The second annealing temperature is 500℃. Figure 1 (c) The second annealing temperature is 550℃. Figure 1 (d) The second annealing temperature is 600℃. It can be seen that as the annealing temperature increases, the grain size increases. After 550℃, the grains are completely transformed into recrystallized grains.

[0054] Figure 2 These are pole figures of the plates obtained in Examples 1-4. Figure 2 (a) The second annealing temperature is 450℃. Figure 2 (b) The second annealing temperature is 500℃. Figure 2 (c) The second annealing temperature is 550℃. Figure 2 (d) The second annealing temperature is 600℃. As can be seen from the figure, the texture type of the plate has changed from the base surface B texture in the low temperature annealing state to the base surface bimodal B texture at 600℃.

[0055] Figure 3 The microstructures of the plates obtained in Examples 5-8 are shown. All of them were obtained through cross-cold rolling, differing only in the second annealing temperature. Figure 3 (a) The second annealing temperature is 450℃. Figure 3 (b) The second annealing temperature is 500℃. Figure 3 (c) The second annealing temperature is 550℃. Figure 3 (d) The second annealing temperature is 600℃. As can be seen from the figure, it is similar to the grain size change with temperature of unidirectional cold-rolled sheet, that is, the grain size increases with increasing temperature.

[0056] Figure 4 The pole figures are those of the plates obtained in Examples 5-8. Figure 4 (a) The second annealing temperature is 450℃. Figure 4 (b) The second annealing temperature is 500℃. Figure 4 (c) The second annealing temperature is 550℃. Figure 4 (d) The second annealing temperature is 600℃. As can be seen from the figure, the texture type changes with the change of the second annealing temperature. It changes from the base surface bimodal texture in the low temperature annealing state to the base surface B texture after heat treatment at 550℃, and the texture strength is greatly reduced.

[0057] A comparative analysis was conducted using Examples 1 and 5. Figure 1 (a) and Figure 3 (a) It can be observed that at this heat treatment temperature, the grains did not completely recrystallize, and the differences in grain morphology and size between the two processes were not significant. This can be further investigated by... Figure 2 (a) and Figure 4 The pole figure comparison in (a) shows that the deformation texture obtained by cross rolling during cold rolling is a bimodal B texture, which ultimately leads to a lower anisotropy of the incomplete recrystallized structure.

[0058] Further mechanical analysis was performed on the plates of Examples 1-8, and the results are shown in Table 1.

[0059] Table 1

[0060] In the table, RD represents the rolling direction, and TD represents the direction perpendicular to the rolling direction, i.e., the transverse direction.

[0061] As shown in Table 1, the sheets prepared in Examples 1-8 all possess excellent mechanical properties, significantly exceeding the requirements of ASTM B551 / B551M-12 standards (tensile strength ≥380MPa, yield strength ≥205MPa, elongation ≥16%). Furthermore, the differences in their transverse and longitudinal mechanical properties are relatively small. The difference in tensile strength between the transverse and longitudinal directions does not exceed 15MPa, the difference in yield strength between the transverse and longitudinal directions does not exceed 50MPa, and the difference in elongation between the transverse and longitudinal directions does not exceed 5%. In particular, the sheets prepared by cross-cold rolling in Examples 5-8 exhibit very weak anisotropy, demonstrating isotropic mechanical properties.

[0062] Further analysis revealed that the plates prepared by unidirectional cold rolling at 600℃ and cross-cold rolling at 550℃ (Examples 4 and 7) showed little difference in transverse and longitudinal mechanical properties. Both plates exhibited weak anisotropy and were at a relatively high strength-plasticity level.

[0063] Using the plates prepared in Examples 4 and 7 as examples, their bending properties were analyzed, and the results are as follows: Figure 5 As shown in the figure, the four samples from left to right are, in order, the T-direction bending state of the sheet material prepared in Example 4, the L-direction bending state of the sheet material prepared in Example 4, the T-direction bending state of the sheet material prepared in Example 7, and the L-direction bending state of the sheet material prepared in Example 7, where T-direction is transverse and L-direction is longitudinal. It can be seen from the figure that no cracks appeared after bending in either the transverse or longitudinal direction for either type of sheet material, indicating that both exhibit excellent bending performance.

[0064] Using the plates prepared in Examples 4 and 7 as examples, a cup-pouring test was conducted, and the results are shown in Table 2.

[0065] Table 2

[0066] As can be seen from the table, both types of plates exhibit low anisotropy, with Example 7, which uses cross-cold rolling, exhibiting even lower anisotropy, a larger average cupping value, and excellent cupping performance.

[0067] The work hardening index (n) and plastic strain ratio (r) of the plates with the lowest anisotropy obtained in Examples 4 and 7 were measured, and the results are shown in Table 3.

[0068] Table 3

[0069] As can be seen from the table, the L-direction (longitudinal) values ​​of the sheet material in Example 4 and the T-direction (transverse) and 45° direction (n-values) of the cross-rolled sheet material in Example 7 are all relatively large, indicating that the material deformation is uniform throughout the forming process, with high forming limit and good crack resistance. The results of measuring the plastic strain ratio (r) values ​​in the three directions show that the unidirectional cold-rolled sheet material in Example 4 has excellent resistance to instability, but the cross-rolled sheet material in Example 7 has a stronger ability to resist instability and thinning, with a larger average value of r1, r2, and r3 in the three directions (the average value of r1, r2, and r3 in the three directions is not less than 18), meaning that thickness deformation is less likely to occur during the sheet material forming process.

[0070] The above test analysis shows that the sheet material obtained in this application not only has excellent mechanical properties, but also has small differences in transverse and longitudinal mechanical properties, exhibiting isotropic characteristics and excellent forming performance.

[0071] Example 9 The procedure is the same as in Example 7, with the only difference being: The deformation during the widening rolling process in step three is 40%.

[0072] Example 10 The procedure is the same as in Example 7, with the only difference being: In step five, the fourth sheet material is subjected to cross-cold rolling with a total deformation of 85%, divided into twelve passes, with a 90° reversal every two passes. The deformation of each pass is 8.75%, 9.3%, 9.9%, 10.7%, 11.6%, 12.7%, 14.1%, 15.9%, 17.5%, 19.6%, 20.4%, and 20.5%, respectively. After cold rolling, the fifth sheet material is obtained.

[0073] Example 11 The procedure is the same as in Example 7, with the only difference being: In step five, the fourth sheet is subjected to cross-cold rolling with a total deformation of 55%, in six passes, with a 90° reversal every two passes. The deformation amounts are 11.3%, 11.8%, 12.5%, 12.8%, 13.4%, and 14% respectively. After cold rolling, the fifth sheet is obtained.

[0074] Example 12 The procedure is the same as in Example 7, with the only difference being: The total deformation of the three rolling processes in steps one, two, and three is 80%, 75%, and 60%, respectively.

[0075] Example 13 The rolling process is carried out in accordance with Example 7, except that the rolling temperature is 900°C in steps one, two and three.

[0076] The mechanical properties of the plates prepared in Examples 9-13 were tested, and the results are shown in Tables 4 and 5.

[0077] Table 4

[0078] Table 5

[0079] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a zirconium alloy plate, characterized in that, The preparation method includes: hot rolling, first annealing, cold rolling and second annealing of zirconium alloy forging billet in sequence, wherein the hot rolling includes at least two rolling passes, the last rolling pass of the hot rolling is cross rolling, and the other rolling passes are unidirectional rolling.

2. The preparation method according to claim 1, wherein, The final hot rolling step includes: first rolling along a first direction of the material to be rolled, and then rolling along a second direction of the material to be rolled, wherein the first direction is perpendicular to the second direction, and the deformation of the rolling along the second direction is 50-55%.

3. The preparation method according to claim 1 or 2, wherein, The total deformation of the cold-rolled material is 70-80%.

4. The preparation method according to any one of claims 1-3, wherein, The cold rolling process includes at least four rolling passes, and the deformation of each rolling pass tends to increase with the increase of the number of rolling passes.

5. The preparation method according to any one of claims 1-4, wherein, The deformation of each pass of the cold rolling process is 5-25%, preferably 8-18%.

6. The preparation method according to any one of claims 1-5, wherein, The hot rolling process includes three rolling passes, and the deformation of each rolling pass tends to increase with the number of rolling passes.

7. The preparation method according to claim 6, wherein, The total deformation of the first hot rolling pass is 50-70%, the total deformation of the second hot rolling pass is 70-80%, and the total deformation of the third hot rolling pass is 70-90%.

8. The preparation method according to any one of claims 1-7, wherein, The hot rolling temperature is 650-750℃.

9. The preparation method according to any one of claims 1-8, wherein, The temperatures for the first and second annealing processes are independently set at 400-650℃, and the times are independently set at 30-50 minutes. Preferably, the cold rolling is unidirectional rolling, and the temperature of the second annealing is 590-610℃; or, The cold rolling is a cross rolling process, and the temperature of the second annealing is 540-560℃.

10. A zirconium alloy sheet prepared by the preparation method according to any one of claims 1-9, characterized in that, The difference between the transverse and longitudinal tensile strength of the zirconium alloy plate shall not exceed 15 MPa, the difference between the transverse and longitudinal yield strength shall not exceed 50 MPa, and the difference between the transverse and longitudinal elongation shall not exceed 5%. Preferably, the difference between the transverse and longitudinal tensile strength of the zirconium alloy plate does not exceed 5 MPa, the difference between the transverse and longitudinal yield strength does not exceed 5 MPa, and the difference between the transverse and longitudinal elongation does not exceed 1%. Preferably, the average value of the plastic strain ratio in the T-direction, the plastic strain ratio in the L-direction, and the plastic strain ratio in the 45° direction of the zirconium alloy plate is not less than 18.

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