Magnesium foil preparation method free of intermediate annealing and capable of being cold-rolled under large pressure

Abstract

The invention discloses an intermediate-annealing-free magnesium foil preparation method capable of being cold-rolled under high pressure, which comprises the following steps: preparing a magnesium alloy cast ingot, and pretreating the magnesium alloy cast ingot to obtain an initial rolled blank plate; at the room temperature, multi-pass rolling with the rolling reduction being 1-30% is conducted on the initially-rolled blank plate, and the thickness of the plate is reduced to the first preset thickness; the plate with the first preset thickness is subjected to multi-pass rolling with the rolling reduction being 30%-50%, and the thickness of the plate is reduced to be the second preset thickness; the rolling force is increased, and rolling is conducted repeatedly till the plate thickness reaches the designated thickness; the whole machining process is carried out at the room temperature, the annealing procedure or high-temperature rolling in a conventional magnesium alloy cold rolling process is omitted, the material surface oxidation phenomenon and the high energy consumption problem in the machining process are avoided, large rolling reduction deformation is adopted in the preparation process, and the production efficiency is improved; the finish-rolled magnesium alloy foil with good flatness and few burrs can be obtained; and the rolling process is simple, and large-scale batch production is easy to realize.

Description

Technical Field

[0001] The invention relates to the technical field of magnesium alloy materials, in particular to a method for preparing a magnesium foil material which has no intermediate annealing and can be cold-rolled with a large reduction. 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 capacity 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 few reports on the preparation of magnesium foil. Since magnesium alloy itself is easily oxidized and has low corrosion resistance, the hot working process will aggravate its surface oxidation, making it difficult to prepare high-quality magnesium foil products. Chinese patent CN 106994464A discloses a cold rolling production process of pure magnesium or magnesium alloy foil. The cold rolling process is as follows: a pure magnesium or magnesium alloy deformed material with a thickness of ≤0.2mm after thermoplastic processing and annealing is used as the initial blank for cold rolling, and the initial blank is repeatedly cold rolled with a small deformation amount of 0.05-0.9% per pass until the foil reaches the required thickness; the deformation amount per pass is 0.05-0.9%, and the maximum thickness of the initial sheet is only 0.2mm, which seriously affects the production efficiency; therefore, in order to prepare high-quality and low-cost magnesium foil, it can only be prepared by 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 deformation ability of magnesium alloys, especially when the lithium content is high, the close-packed hexagonal structure of magnesium alloys can be completely transformed into a body-centered cubic structure, and the number of independent slip systems at room temperature increases, making cold processing of magnesium alloys possible. In fact, magnesium-lithium alloy is an important branch of magnesium alloys. 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, and it also has the performance 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 shock absorption, noise reduction and electromagnetic shielding of materials. In this field, metal foil is the most widely used material. Magnesium-lithium alloy happens to have the above-mentioned advantages and formable foil products, so magnesium alloy foil has broad application prospects in this field.

[0004] Foil refers to a thin plate or strip with a thickness of less than or equal to 0.1mm. For magnesium alloy foil, the existing preparation process is 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, magnesium-lithium alloys can be rolled to 0.02mm or even 0.014mm, such as patents CN111004951B and CN108817084B, the magnesium-lithium foil preparation method provided by the above technology still uses hot rolling or annealing to ensure the quality of the foil, the process energy consumption is still high, and the foil thickness does not reach 0.01mm; it can be seen that the existing magnesium-lithium foil preparation technology and processing procedures are still relatively complicated (requiring hot rolling and annealing), and the cost and energy consumption are high. Therefore, a magnesium foil preparation method without intermediate annealing and capable of large-pressure 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] In order to solve the above technical problems, the present invention adopts the following technical solution: a method for preparing a magnesium foil material without intermediate annealing and capable of large 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. At room temperature, the initially rolled blank plate is subjected to multiple rolling passes with a reduction of 1-30% to reduce the plate thickness 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 the 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 in 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 in all passes are 10-30% until the plate thickness is reduced to a first preset thickness, wherein the roller speed is 15-20 m / min.

[0018] Preferably, in step S3, the reduction amount in the first three passes is 30-40%, and the reduction amount 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.

[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 intermediate 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 phenomenon of the material and the high energy consumption problem in the processing process, and improving the surface finish; the preparation process adopts large-scale deformation to improve the production efficiency, and after multiple passes of room temperature cold rolling, a finely 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 picture:

[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 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 drawings. It is known to those of ordinary skill 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 also applicable to similar technical problems. The terms "first", "second", etc. in the specification and claims of the present 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 can be interchangeable where appropriate, which is only to describe the distinction between the objects of the same attributes in the embodiments of the present application when describing them. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, so that the process, method, system, product or device containing a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] Embodiment: A method for preparing a magnesium foil material without intermediate annealing and capable of large-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 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;

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

[0036] a. Put all raw materials into the 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 is as follows: cutting the prepared magnesium alloy ingot into rectangular alloy plates and removing the oxide scale to obtain the initial rolling billet;

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

[0041] Wherein, 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 in all passes are 10-30%, until the plate thickness is reduced to the first preset thickness, wherein the roller speed is 15-20 m / 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 amount of the first three passes is 30-40%, and the reduction amount of 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, increasing the rolling force and rolling repeatedly until the plate thickness reaches the specified thickness; wherein the reduction in a single pass is 5-50%, wherein the roller speed is 5-10 m / min.

[0045] The plates with the specified thickness are finished to completely solve the problems of wavy edges, coil cracks and center bumps, and the thickness tolerance is 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 drops 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] For 0.5mm plate, a small-tonnage single-roller / multi-roller mill is used to perform multiple cold rolling with a large deformation amount of 30-50% reduction; among them, the reduction amount of the first three passes is 30-40%, and the reduction amount of all subsequent passes is 40-50%, until the thickness of the magnesium alloy foil is reduced to 0.1-0.05mm; reference Figure 2 As shown, the thickness of magnesium foil is 0.101mm. Figure 3 As shown, the thickness of the magnesium foil is 0.049 mm; the error is within ±0.005.

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

[0050] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. For ordinary technicians in this technical field, after knowing the contents recorded in the present invention, they can make several equivalent changes and substitutions without departing from the principle of the present invention. These equivalent changes and substitutions should also be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for preparing magnesium foil without intermediate annealing and capable of large 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. At room temperature, the initially rolled blank plate is subjected to multiple rolling passes with a reduction of 1-30% to reduce the plate thickness to a 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; S4. Increase the rolling force and roll repeatedly until the plate thickness reaches the specified thickness.

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

3. The method for preparing a magnesium foil material without intermediate annealing and capable of large reduction cold rolling according to claim 2, characterized in that: The preparation process of the magnesium alloy ingot is as follows: a. Put all raw materials into the 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 in a copper mold to obtain a magnesium alloy ingot.

4. The method for preparing a magnesium foil material without intermediate annealing and capable of large reduction cold rolling according to claim 3, characterized in that: 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.

5. The method for preparing a magnesium foil material without intermediate annealing and capable of large reduction cold rolling according to claim 4, characterized in that: 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.

6. The method for preparing a magnesium foil material without intermediate annealing and capable of large reduction cold rolling according to claim 5, characterized in that: In step S3, the reduction amount of the first three passes is 30-40%, and the reduction amount of 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.

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

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