A method for preparing magnesium foil without intermediate annealing and capable of high-reduction cold rolling

Abstract

The invention discloses a method for preparing a magnesium foil material that does not require intermediate annealing and can be cold-rolled with large reduction. The method comprises the following steps: preparing a magnesium alloy ingot and pre-treating the ingot to obtain an initial rolled blank plate; performing multiple rolling passes with a reduction of 1-30% on the initial rolled blank plate at room temperature to reduce the plate thickness to a first preset thickness; performing multiple rolling passes with a reduction of 30%-50% on the plate with the first preset thickness to reduce the plate thickness to a second preset thickness; increasing the rolling force and repeatedly rolling until the plate thickness reaches a specified thickness; the entire processing process is carried out at room temperature, eliminating the annealing process or high-temperature rolling in a conventional magnesium alloy cold rolling process, avoiding the surface oxidation of the material and the high energy consumption problem in the processing process; adopting large reduction deformation in the preparation process to improve production efficiency; and obtaining a fine-rolled magnesium alloy foil material with good flatness and less burrs after multiple cold rolling passes at room temperature; the rolling process is simple and easy to achieve large-scale batch production.

Description

Technical Field

[0001] The present invention relates to the technical field of magnesium alloy materials, in particular to a method for preparing a magnesium foil material which does not require intermediate annealing and can be subjected to high-reduction cold rolling. Background Art

[0002] Magnesium alloy is the lightest structural metal material with a hexagonal close-packed crystal structure and few independent slip systems at room temperature, resulting in extremely poor plasticity of magnesium alloy and inability to undergo cold deformation processing. Although high temperature environment can improve the deformation ability of magnesium alloy, this can easily cause oxidation or even burning of the magnesium alloy surface during hot processing, seriously affecting the quality of magnesium alloy products. In addition, the hot processing process and technology are relatively complex and energy-intensive. There are even fewer reports on the preparation of magnesium foil. Since magnesium alloys are inherently susceptible to oxidation and have low corrosion resistance, thermal processing will exacerbate surface oxidation, making it difficult to produce high-quality magnesium foil products. Chinese patent CN 106994464 A discloses a cold rolling production process for pure magnesium or magnesium alloy foil. The cold rolling process involves using a pure magnesium or magnesium alloy deformed material with a thickness of ≤0.2 mm that has undergone thermoplastic processing and annealing as the initial cold rolling blank. The initial blank is repeatedly cold rolled with a small deformation amount of 0.05-0.9% per pass until the foil reaches the desired thickness. The deformation amount per pass is 0.05-0.9%, and the maximum initial sheet thickness is only 0.2 mm, which seriously affects production efficiency. Therefore, the only way to produce high-quality and low-cost magnesium foil is through a cold rolling process without annealing and with a large reduction.

[0003] Based on a large number of previous literature reports, the addition of lithium can significantly improve the deformability of magnesium alloys. Especially when the lithium content is high, the close-packed hexagonal structure of the magnesium alloy can be completely transformed into a body-centered cubic structure, and the number of independent slip systems at room temperature increases, making cold working of the magnesium alloy possible. In fact, magnesium-lithium alloy is an important branch of magnesium alloy. As the lightest metal structural material in the world, compared with other aluminum alloys and magnesium alloys, it also has many unique advantages such as ultra-low density, high specific strength, high specific stiffness, and outstanding shock absorption performance. It is an ideal weight-reducing material in aerospace and military applications, and also has the properties of shock absorption, noise reduction, and electromagnetic interference shielding. In addition, in the field of audio or headphones, there are extremely high requirements for the material's shock absorption, noise reduction, and electromagnetic shielding properties. In this field, metal foil is the most widely used material. Magnesium-lithium alloy just happens to have the above-mentioned advantages and formable foil products. Therefore, magnesium alloy foil has broad application prospects in this field.

[0004] Foil refers to thin strips with a thickness of less than or equal to 0.1 mm. For magnesium alloy foil, existing preparation processes are difficult to achieve large-scale continuous production, and the cost remains high. In recent years, although many scholars have developed a series of foil preparation technologies for magnesium-lithium alloys, which can be rolled to 0.02 mm or even 0.014 mm, such as patents CN111004951B and CN108817084B, the magnesium-lithium foil preparation methods provided by these technologies still use hot rolling or annealing to ensure foil quality, the process energy consumption is still high, and the foil thickness does not reach 0.01 mm. It can be seen that the existing magnesium-lithium foil preparation technology and processing procedures are still relatively complex (requiring hot rolling and annealing), with high cost and energy consumption. Therefore, a magnesium foil preparation method without intermediate annealing and capable of high-reduction cold rolling is urgently needed to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing magnesium foil without intermediate annealing and capable of large-reduction cold rolling, which can effectively solve the problems existing in the above-mentioned prior art.

[0006] To solve the above technical problems, the present invention adopts the following technical solution: a method for preparing magnesium foil without intermediate annealing and capable of high-reduction cold rolling, comprising the following steps:

[0007] S1. preparing a magnesium alloy ingot and pretreating the ingot to obtain an initial rolled billet plate;

[0008] S2. performing multiple rolling of the initially rolled blank plate at room temperature with a reduction of 1-30% to reduce the thickness of the plate to a first preset thickness;

[0009] S3, performing multiple rolling with a reduction of 30%-50% on the plate of the first preset thickness, so that the thickness of the plate is reduced to a second preset thickness;

[0010] S4. Increase the rolling force and roll repeatedly until the plate thickness reaches the specified thickness.

[0011] Preferably, the raw materials of each component in the magnesium alloy ingot and their mass percentages are: Li is 9-20%, Zn is 0-20%, and the balance is Mg.

[0012] Preferably, the preparation process of the magnesium alloy ingot is:

[0013] a. Put all raw materials into medium frequency vacuum induction melting furnace and evacuate the furnace to make the vacuum degree lower than 1×10 -3 Pa; introduce argon protection, and stop filling argon when the pressure reaches 0.05-0.07MPa;

[0014] b. Use 1.8-2.2kw low power to heat the raw materials until they melt, and increase the power to 3.8-4.2kw to keep them warm after they melt;

[0015] c. Casting into a copper mold to obtain a magnesium alloy ingot.

[0016] Preferably, in step S1, the pretreatment is: cutting the prepared magnesium alloy ingot into rectangular alloy plates, and removing the oxide scale to obtain an initial rolled billet.

[0017] Preferably, in step S2, an intermediate thickness is set, and the single-pass reduction before the plate thickness drops to the intermediate thickness is 1-10%, and the subsequent reductions are 10-30% until the plate thickness is reduced to the first preset thickness, wherein the roller speed is 15-20 m / min.

[0018] Preferably, in step S3, the reduction in the first three passes is 30-40%, and the reduction in all subsequent passes is 40-50%, until the thickness of the plate drops to a second preset thickness, wherein the roller speed is 10-15 m / min.

[0019] Preferably, in step S4, the reduction in a single pass is 5-50%, wherein the roller speed is 5-10 m / min.

[0020] Preferably, in step S4, the plate is finished to a specified thickness, and the plate thickness tolerance is less than ±0.005.

[0021] Preferably, the thickness of the initial rolled blank plate is 5-15 mm; the first preset thickness is 0.5 mm; the second preset thickness is 0.1-0.05 mm; and the designated thickness is 0.01 mm.

[0022] Preferably, in step S2, the middle thickness is 3 mm.

[0023] Beneficial effects: The entire processing process of the present invention is carried out at room temperature, eliminating the annealing process or high-temperature rolling in the conventional magnesium alloy cold rolling process, avoiding the surface oxidation of the material and the high energy consumption problem in the processing process, and improving the surface finish; the preparation process adopts large-reduction deformation, which improves production efficiency, and after multiple passes of room-temperature cold rolling, a fine-rolled magnesium alloy foil with good flatness and less burrs can be obtained; the rolling process is simple, low-cost, high-efficiency, and easy to achieve large-scale batch production;

[0024] In addition, the present invention can use a small-tonnage multi-roll mill or a single-roll mill to achieve the preparation of ultra-thin foil, and the preparation of the foil has low requirements on equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0026] In the attached figure:

[0027] Figure 1 Schematic diagram of a magnesium alloy foil with a thickness of 0.5 mm prepared by the present invention;

[0028] Figure 2 Schematic diagram of a magnesium alloy foil with a thickness of 0.1 mm prepared by the present invention;

[0029] Figure 3 Schematic diagram of a magnesium alloy foil with a thickness of 0.05 mm prepared by the present invention;

[0030] Figure 4 It is a schematic diagram of a magnesium alloy foil with a thickness of 0.01 mm prepared by the present invention. DETAILED DESCRIPTION

[0031] The following describes the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. The terms used in the embodiments of the present invention are only used to explain the specific embodiments of the present invention and are not intended to limit the present invention. The following describes the embodiments of the present application in conjunction with the accompanying drawings. It will be appreciated by those skilled in the art that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are equally applicable to similar technical problems. The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate. This is merely a way of distinguishing objects with the same properties when describing the embodiments of the present application. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion, so that a process, method, system, product or device that includes a series of units is not necessarily limited to those units, but may include other units that are not explicitly listed or inherent to these processes, methods, products or devices.

[0032] Example: A method for preparing a magnesium foil material without intermediate annealing and capable of high-reduction cold rolling comprises the following steps:

[0033] S1. preparing a magnesium alloy ingot and pretreating the ingot to obtain an initial rolled billet plate;

[0034] The raw materials and their mass percentages of the components in the magnesium alloy ingot are as follows: Li is 9-20%, Zn is 0-20%, and the balance is Mg;

[0035] The preparation process of magnesium alloy ingot is as follows:

[0036] a. Put all raw materials into medium frequency vacuum induction melting furnace and evacuate the furnace to make the vacuum degree lower than 1×10 -3 Pa; introduce argon protection, and stop filling argon when the pressure reaches 0.05-0.07MPa;

[0037] b. Use 1.8-2.2kw low power to heat the raw materials until they melt, and increase the power to 3.8-4.2kw to keep them warm after they melt;

[0038] c. Casting in a copper mold to obtain a magnesium alloy ingot;

[0039] The pretreatment comprises the following steps: cutting the prepared magnesium alloy ingot into rectangular alloy plates and removing the oxide scale to obtain the initial rolled billet;

[0040] S2. performing multiple rolling of the initially rolled blank plate at room temperature with a reduction of 1-30% to reduce the thickness of the plate to a first preset thickness;

[0041] Wherein, an intermediate thickness is set, and the reduction amount of a single pass before the thickness of the plate is reduced to the intermediate thickness is 1-10%, and the reduction amount of all subsequent passes is 10-30% until the thickness of the plate is reduced to the first preset thickness, wherein the roller speed is 15-20m / min;

[0042] S3, performing multiple rolling with a reduction of 30%-50% on the plate of the first preset thickness, so that the thickness of the plate is reduced to a second preset thickness;

[0043] The reduction in the first three passes is 30-40%, and the reduction in all subsequent passes is 40-50%, until the thickness of the plate is reduced to a second preset thickness, wherein the roller speed is 10-15 m / min;

[0044] S4. Increase the rolling force and roll repeatedly until the plate thickness reaches the specified thickness; wherein the reduction in a single pass is 5-50%, and wherein the roller speed is 5-10 m / min.

[0045] Finishing of plates to specified thickness can completely solve the problems of wavy edges, coil cracks and center bumps, with a thickness tolerance of less than ±0.005.

[0046] In a specific embodiment, the thickness of 10 mm is obtained by using the above method, and the initial rolled billet is obtained after removing the oxide scale;

[0047] Then, at room temperature, the initial billet is operated using a small-tonnage single-roll / multi-roll mill, and the intermediate thickness is set to 3 mm; the single-pass reduction before the plate thickness is reduced to 3 mm is 1-10%, and the subsequent reductions are 10-30% until the plate thickness is reduced to 0.5 mm. Figure 1 As shown, the magnesium foil has a thickness of 0.5 mm.

[0048] The 0.5 mm plate is subjected to multiple cold rolling with a large deformation amount of 30-50% using a small tonnage single-roll / multi-roll mill; the first three passes have a rolling reduction of 30-40%, and all subsequent passes have a rolling reduction of 40-50%, until the thickness of the magnesium alloy foil is reduced to 0.1-0.05 mm; Figure 2 As shown, the thickness of the magnesium foil is 0.101 mm. Figure 3 The figure shows a magnesium foil with a thickness of 0.049 mm; the error is within ±0.005.

[0049] For magnesium alloy foil of 0.1-0.05 mm, the rolling force between the two rolls of a small-tonnage single-roll / multi-roll mill is increased at room temperature, and cold rolling is repeated with a single-pass reduction of 5-50% until the foil is rolled to a thickness of 0.01 mm; Figure 4 As shown, the magnesium foil has a thickness of 0.01 mm.

[0050] The above describes the embodiments of the present invention in detail with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. After knowing the contents described in the present invention, ordinary technicians in this technical field can make several equivalent changes and substitutions without departing from the principles of the present invention. These equivalent changes and substitutions should also be regarded as falling within the scope of protection of the present invention.

Claims

1. A method for preparing magnesium foil without intermediate annealing and capable of high-reduction cold rolling, characterized in that: The steps include: S1. preparing a magnesium alloy ingot and pretreating the ingot to obtain an initial rolled billet plate; S2. performing multiple rolling of the initially rolled blank plate at room temperature with a reduction of 1-30% to reduce the thickness of the plate to a first preset thickness; An intermediate thickness is set, and the single-pass reduction before the plate thickness is reduced to the intermediate thickness is 1-10%, and the subsequent reductions are 10-30% until the plate thickness is reduced to the first preset thickness; S3, performing multiple rolling with a reduction of 30%-50% on the plate of the first preset thickness, so that the thickness of the plate is reduced to a second preset thickness; The first three passes have a reduction of 30-40%, and all subsequent passes have a reduction of 40-50% until the plate thickness is reduced to the second preset thickness; S4. Increase the rolling force and repeat rolling until the plate thickness reaches the specified thickness.

2. The method for preparing a magnesium foil material capable of high-reduction cold rolling without intermediate annealing according to claim 1, characterized in that: The raw materials of the magnesium alloy ingot and their mass percentages are as follows: Li is 9-20%, Zn is 0-20%, and the balance is Mg.

3. The method for preparing a magnesium foil material capable of high-reduction cold rolling without intermediate annealing according to claim 2, characterized in that: The preparation process of the magnesium alloy ingot is as follows: a. Put all raw materials into medium frequency vacuum induction melting furnace and evacuate the furnace to make the vacuum degree lower than 1×10 -3 Pa; introduce argon protection, and stop filling argon when the pressure reaches 0.05-0.07MPa; b. Use 1.8-2.2kw low power to heat the raw materials until they melt, and increase the power to 3.8-4.2kw to keep them warm after they melt; c. Casting into a copper mold to obtain a magnesium alloy ingot.

4. The method for preparing a magnesium foil material capable of high-reduction cold rolling without intermediate annealing according to claim 3, characterized in that: In step S1 , the pretreatment is as follows: cutting the prepared magnesium alloy ingot into rectangular alloy plates and removing the oxide scale to obtain an initial rolled billet.

5. The method for preparing a magnesium foil material capable of high-reduction cold rolling without intermediate annealing according to claim 4, characterized in that: In step S2, the roller rotation speed is 15-20 m / min.

6. The method for preparing a magnesium foil material capable of high-reduction cold rolling without intermediate annealing according to claim 5, characterized in that: In step S3, the roller rotation speed is 10-15 m / min.

7. The method for preparing a magnesium foil material capable of high-reduction cold rolling without intermediate annealing according to claim 6, characterized in that: In step S4, the reduction in a single pass is 5-50%, wherein the roller speed is 5-10 m / min.

8. The method for preparing a magnesium foil material capable of high-reduction cold rolling without intermediate annealing according to claim 1 or 7, characterized in that: In step S4, the plate is finished to a specified thickness, and the plate thickness tolerance is less than ±0.

005.

9. The method for preparing a magnesium foil material capable of high-reduction cold rolling without intermediate annealing according to claim 7, characterized in that: The thickness of the initial rolled blank plate is 5-15 mm; the first preset thickness is 0.5 mm; the second preset thickness is 0.1-0.05 mm; and the designated thickness is 0.01 mm.

10. The method for preparing magnesium foil without intermediate annealing and capable of high-reduction cold rolling according to claim 9, characterized in that: In step S2, the intermediate thickness is 3 mm.

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