Magnesium-lithium alloy thin-walled pipe and method for manufacturing the same

Abstract

The application belongs to the technical field of pipe material preparation, and particularly relates to a magnesium-lithium alloy thin-walled pipe material and a preparation method thereof. The preparation method of the magnesium-lithium alloy thin-walled pipe material comprises the following steps: spinning forming a magnesium-lithium alloy blank to obtain a magnesium-lithium alloy thin-walled pipe material; the magnesium-lithium alloy blank comprises the following components in mass fraction: 8.0%-16.0% Li, 1.0%-5.0% Al, 0.5%-3% Zn, 0.1%-3% rare earth elements, and the balance is magnesium and inevitable impurities. The preparation method of the magnesium-lithium alloy thin-walled pipe material provided by the application realizes efficient forming of magnesium-lithium alloy small and medium-sized thin-walled pipe material, and improves the economy and flexibility of production and preparation.

Description

Technical Field

[0001] This invention belongs to the field of pipe manufacturing technology, specifically relating to a magnesium-lithium alloy thin-walled pipe and its manufacturing method. Background Technology

[0002] Magnesium-lithium alloy tubing can be used in the fabrication of structural components for satellites, spacecraft, and other applications, offering significant weight reduction benefits. The development of satellite and spacecraft structural components often involves adjustments to design dimensions, leading to variations in the specifications of magnesium-lithium alloy tubing and fluctuations in total demand. Currently, traditional production processes such as integral machining, extrusion, or die forging lack economic efficiency and flexibility, limiting the application of magnesium-lithium alloy tubing: integral machining results in low material utilization and excessive raw material waste; extrusion equipment is expensive to operate, with costs only reasonably amortized for large-scale production exceeding 5 tons; die forging is suitable for producing cylindrical components with small height-to-diameter ratios, but producing long, thin tubing is difficult, and the heavy and bulky forging dies result in high manufacturing costs. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a magnesium-lithium alloy thin-walled tube, its preparation method, and its applications. This addresses at least one aspect of solving the above-mentioned technical problems.

[0004] This invention is achieved through the following technical solution: In a first aspect, the present invention provides a method for preparing a magnesium-lithium alloy thin-walled tube, comprising the following steps: Magnesium-lithium alloy blanks are spun into thin-walled magnesium-lithium alloy tubes. The magnesium-lithium alloy billet comprises the following components by mass fraction: 8.0%~16.0%Li, 1.0%~5.0%Al, 0.5%~3%Zn, 0.1%~3%Rare Earth elements, with the balance being magnesium and unavoidable impurities.

[0005] In some possible implementations, the single-pass reduction rate of the spinning process is 10% to 50%.

[0006] In some possible implementations, the total reduction of the spinning process is no more than 80%.

[0007] In some possible implementations, the spindle speed in the spinning process is 20 rpm to 70 rpm.

[0008] In some possible implementations, the axial feed ratio in the spinning process is 0.6 mm / r to 5 mm / r.

[0009] In some possible implementations, the rare earth element includes at least one of Gd, Y, Er, and Nd.

[0010] In some possible implementations, the thickness of the magnesium-lithium alloy billet is 1.5t to 5t, where t is the target wall thickness of the magnesium-lithium alloy thin-walled tube.

[0011] In some possible implementations, the height of the magnesium-lithium alloy billet is greater than 1.5 times the thickness of the spool.

[0012] In some possible implementations, the preparation method further includes the following steps: The material obtained by spinning is then subjected to spinning shaping treatment.

[0013] In some possible implementations, the amount of downward pressure in the spinning and shaping process is 0.5 mm to 1 mm.

[0014] In some possible implementations, the spindle speed in the spinning and shaping process is 10 rpm to 30 rpm.

[0015] In some possible implementations, the feed rate in the spinning and shaping process is 1 mm / s to 10 mm / s.

[0016] Secondly, the present invention provides a magnesium-lithium alloy thin-walled tube prepared by the above-mentioned method for preparing magnesium-lithium alloy thin-walled tubes.

[0017] In some possible implementations, the outer diameter of the magnesium-lithium alloy thin-walled tube is Φ50mm~250mm.

[0018] In some possible implementations, the wall thickness of the magnesium-lithium alloy thin-walled tube is 1 mm to 5 mm.

[0019] The method for preparing magnesium-lithium alloy thin-walled tubing provided by this invention has at least the following beneficial technical effects compared with the prior art: The method for preparing magnesium-lithium alloy thin-walled tubing provided by this invention enables efficient forming of small and medium-sized magnesium-lithium alloy thin-walled tubing components, improving the economy and flexibility of production. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this drawing or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this drawing. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 This is a structural diagram of the magnesium-lithium alloy thin-walled tube in Embodiment 1 of the present invention.

[0022] The purpose, features, and advantages of this accompanying drawing will be further explained in conjunction with the embodiments and with reference to the accompanying drawing. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described and illustrated below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.

[0024] Obviously, the following description is merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0025] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand the invention and is not intended to limit the subject matter of the claims.

[0026] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.

[0027] [Preparation Method of Magnesium-Lithium Alloy Thin-Walled Tubes] The first aspect of this invention provides a method for preparing a magnesium-lithium alloy thin-walled tube, comprising the following steps: S10. Spin-form the magnesium-lithium alloy billet to obtain a magnesium-lithium alloy thin-walled tube; The magnesium-lithium alloy billet comprises the following components by mass fraction: 8.0%~16.0%Li, 1.0%~5.0%Al, 0.5%~3%Zn, 0.1%~3%Rare Earth elements, with the balance being magnesium and unavoidable impurities.

[0028] The method for preparing magnesium-lithium alloy thin-walled tubing provided in this invention uses spin forming technology to produce magnesium-lithium alloy thin-walled tubing, achieving efficient forming of small and medium-sized magnesium-lithium alloy thin-walled tubing parts and improving the economy and flexibility of production.

[0029] In some embodiments, in step S10 above, the rare earth element includes at least one of Gd, Y, Er, and Nd.

[0030] In some embodiments, in step S10 above, the thickness of the magnesium-lithium alloy billet is 1.5t to 5t, where t is the target wall thickness of the magnesium-lithium alloy thin-walled tube. In this case, the total wall thickness reduction is within 80%, which conforms to the conventional deformation characteristics of magnesium-lithium alloys. When the wall thickness is too thick, there are too many cold spinning passes, and the high degree of surface work hardening leads to lower spinning efficiency in subsequent passes; when the wall thickness is too thin, it is unnecessary to use the spinning process.

[0031] In some embodiments, during step S10, the height of the magnesium-lithium alloy billet is greater than 1.5 times the thickness of the spinning wheel. In this case, the spinning wheel will not travel to the very edge, allowing a flange to be left at the edge of the workpiece, thus enhancing the rigidity of the workpiece during spinning.

[0032] In some embodiments, in step S10 above, the magnesium-lithium alloy billet is a cylindrical part.

[0033] In some embodiments, in step S10 above, the surface roughness of the magnesium-lithium alloy billet is Ra3.2 or less. In this case, the friction between the billet and the spinning wheel is small, avoiding rapid wear of the spinning wheel, reducing local stress concentration on the outer surface, and preventing the formation and propagation of surface cracks.

[0034] In some embodiments, in step S10 above, the single-pass reduction rate of spinning is 10% to 50%. In this case, the deformation efficiency of the magnesium-lithium alloy is taken into account, while preventing excessive single-pass deformation from causing cracking.

[0035] In some embodiments, in step S10 above, the total reduction of the spinning process is no more than 80%. In this case, the magnesium-lithium alloy is sufficiently deformed and strengthened without cracking.

[0036] In some embodiments, the spindle speed during spinning is 20 rpm to 70 rpm. In this case, the surface quality is better.

[0037] In some embodiments, during step S10 above, the axial feed ratio in the spinning process is 0.6 mm / r to 5 mm / r. In this case, when the spindle speed is high and the feed ratio is set large, frictional heat is generated, and the surface quality decreases significantly. At the same time, magnesium-lithium alloys are sensitive to temperature and are prone to softening at high temperatures. Excessive sacrifice of rigidity can easily cause local cracking or bulging. The workpiece temperature should be measured after each pass. When the workpiece temperature exceeds 80°C, it should be cooled in time before starting the next pass.

[0038] In some embodiments, in step S10 above, the spinning method in spinning forming is either forward spinning or reverse spinning.

[0039] In some embodiments, during step S10 above, the surface hardness of the mandrel in the spinning process is 50 HRC to 70 HRC. In this case, the mandrel typically has better wear resistance.

[0040] In some embodiments, during step S10 above, the surface hardness of the spinning wheel in the spinning process is 50 HRC to 70 HRC. In this case, the spinning wheel typically has better wear resistance.

[0041] In some embodiments, the spinning equipment is a two-wheel horizontal spinning machine or a three-wheel horizontal spinning machine.

[0042] In some embodiments, a method for preparing a magnesium-lithium alloy thin-walled tube is provided, which further includes the following steps: S20. The material obtained by spinning is subjected to spinning shaping treatment.

[0043] In this case, the outer diameter and wall thickness of the pipe are precisely adjusted.

[0044] In some embodiments, during the spinning shaping process in step S20 described above, the pressure applied is 0.5 mm to 1 mm. In this case, a small amount of spinning is performed to treat localized surface or dimensional defects, while retaining the surface-hardened layer formed by spinning.

[0045] In some embodiments, during the spinning and shaping process in step S20, the spindle speed is 10 rpm to 30 rpm. In this case, the spindle speed is lower than that during the thinning stage to prevent insufficient rigidity of the thin-walled part at high speeds, which could lead to cracking, wrinkling, etc.

[0046] In some embodiments, during the spinning and shaping process in step S20, the feed rate is 1 mm / s to 10 mm / s. In this case, the feed rate is higher than that of the thinning stage to prevent the spinning wheel from repeatedly rubbing against the blank for a long time, causing surface defects.

[0047] Magnesium-lithium alloy thin-walled tubing The second aspect of the present invention provides a magnesium-lithium alloy thin-walled tube prepared by the above-mentioned method for preparing magnesium-lithium alloy thin-walled tubes.

[0048] In some embodiments, the outer diameter of the magnesium-lithium alloy thin-walled tube is Φ50mm~250mm.

[0049] In some embodiments, the wall thickness of the magnesium-lithium alloy thin-walled tube is 1 mm to 5 mm.

[0050] The following description, in conjunction with specific embodiments, provides further details.

[0051] Example 1 Example 1 provides a method for preparing a magnesium-lithium alloy thin-walled tube, the steps of which are as follows: E10. Obtain cylindrical parts from magnesium-lithium alloy billets; The magnesium-lithium alloy billet consists of the following components by mass fraction: 9.0% Li, 4.0% Al, 2% Zn, 1% Gd, balance being magnesium and unavoidable impurities; The outer diameter of the magnesium-lithium alloy billet cylindrical part is Φ131mm, the wall thickness is 10mm, the height is 150mm, and the surface roughness is Ra.3.2.

[0052] E20. The equipment uses a double-wheel horizontal spinning machine, and neither the die nor the blank needs to be preheated before spinning. The machine is equipped with tools such as spinning wheels, mandrels, and tail tops. The mandrel has an outer diameter of 110mm, a surface smoothness of Ra0.8, and a cylindricity of 0.02mm.

[0053] E30. Spin forming: The spindle speed is set to 15% ± 5% per pass, with a total of 4 passes. The spindle speed is set to 40 rpm ± 10 rpm, and the feed ratio is set to 1 mm / r. During the spinning process, a water-based coolant containing emulsion is sprayed onto the spinning area for cooling.

[0054] E40. Spin forming process: Forming is performed at a spindle speed of 20 rpm and a feed rate of 0.5 mm / s to obtain the following result: Figure 1 The magnesium-lithium alloy thin-walled tube shown has an inner wall cylindricity tolerance of 0.08mm, a wall thickness of 2.5mm, and a uniform surface without peeling or cracking.

[0055] Example 2 Example 2 provides a method for preparing a magnesium-lithium alloy thin-walled tube, the steps of which are as follows: E11. Obtain cylindrical parts from magnesium-lithium alloy billets; The magnesium-lithium alloy billet consists of the following components by mass fraction: 9.0% Li, 4.0% Al, 2% Zn, 1% Gd, balance being magnesium and unavoidable impurities; The outer diameter of the magnesium-lithium alloy billet cylindrical part is Φ235mm, the wall thickness is 12mm, the height is 200mm, and the surface roughness is Ra.3.2.

[0056] E21. The equipment uses a three-wheel horizontal spinning machine, and neither the die nor the blank needs to be preheated before spinning. The machine is equipped with tools such as spinning wheels, mandrels, and tail tops. The mandrel has an outer diameter of 210mm, a surface smoothness of Ra0.8, and a cylindricity of 0.02mm.

[0057] E31. Spin forming: The spindle speed is set to 25% ± 5% per pass, with a total of 3 passes. The spindle speed is set to 60 rpm ± 10 rpm, and the feed ratio is set to 0.8 mm / r. During the spinning process, a water-based coolant containing emulsion is sprayed onto the spinning area for cooling.

[0058] E41. Spin forming process: The forming is carried out with a pressing amount of 0.5mm, a spindle speed of 20rpm, and a feed rate of 2mm / s to obtain a magnesium-lithium alloy thin-walled tube. The inner wall cylindricity of the tube meets the tolerance requirement of 0.2mm, the wall thickness is 3mm, and the surface is free of cracks and pits.

[0059] Example 3 Example 3 provides a method for preparing a magnesium-lithium alloy thin-walled tube, the steps of which are basically the same as those in Example 1, except that: In the spinning process of step E30, the feed ratio is set to 5 mm / r.

[0060] Example 4 Example 4 provides a method for preparing a magnesium-lithium alloy thin-walled tube, the steps of which are basically the same as those in Example 1, except that: In the spinning process of step E30, the feed ratio is set to 0.6 mm / r.

[0061] Comparative Example 1 Comparative Example 1 provides a method for preparing a thin-walled magnesium-lithium alloy tube, the steps of which are basically the same as those in Example 1, except that: In the spinning process of step E30, the single-pass reduction rate is set to 60%, a total of 4 spinning passes are performed, the spindle speed is 80 rpm, and the feed ratio is set to 6 mm / r.

[0062] To verify the advancement of the method for preparing a magnesium-lithium alloy thin-walled tube provided in this embodiment of the invention, the tensile strength, yield strength, and elongation of the magnesium-lithium alloy billet cylindrical parts (before spinning) and magnesium-lithium alloy thin-walled tubes (after spinning) prepared in this embodiment and comparative example of the invention were tested. The results are shown in Table 1 below.

[0063] Table 1

[0064] From the table above, at least the following conclusions can be drawn: (1) In the table above, the yield strength and tensile strength of the pipe obtained after spinning are higher than those before spinning, and both meet industry requirements. It can be seen that the method for preparing magnesium-lithium alloy thin-walled pipes provided in this embodiment of the invention can achieve efficient forming of small and medium-sized magnesium-lithium alloy thin-walled pipe parts, and improve the economy and flexibility of production.

[0065] (2) In the comparative example, the single-pass reduction rate, spindle speed, and feed ratio were all higher than those in the example. The prepared tubes showed defects such as peeling and local microcracks on the surface, and the spinning process was noticeably shaky. It can be seen that the method for preparing magnesium-lithium alloy thin-walled tubes provided in the embodiments of the present invention can only produce tubes that meet the requirements under given spinning spindle speed, feed ratio, and single-pass reduction conditions.

[0066] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A method for preparing a thin-walled magnesium-lithium alloy tube, characterized in that, Includes the following steps: Magnesium-lithium alloy blanks are spun into thin-walled magnesium-lithium alloy tubes. The magnesium-lithium alloy billet comprises the following components by mass fraction: 8.0%~16.0%Li, 1.0%~5.0%Al, 0.5%~3%Zn, 0.1%~3%Rare Earth elements, with the balance being magnesium and unavoidable impurities.

2. The method for preparing the magnesium-lithium alloy thin-walled tube according to claim 1, characterized in that, The single-pass reduction rate of the spinning forming is 10% to 50%.

3. The method for preparing the magnesium-lithium alloy thin-walled tube according to claim 1 or 2, characterized in that, The total reduction in the spinning process shall not exceed 80%.

4. The method for preparing the magnesium-lithium alloy thin-walled tube according to any one of claims 1 to 3, characterized in that, In the spinning process, the spindle speed is 20 rpm to 70 rpm.

5. The method for preparing the magnesium-lithium alloy thin-walled tube according to any one of claims 1 to 4, characterized in that, In the spinning process, the axial feed ratio is 0.6 mm / r to 5 mm / r.

6. The method for preparing the magnesium-lithium alloy thin-walled tube according to any one of claims 1 to 5, characterized in that, It satisfies at least one of the following characteristics (1) to (3): (1) The rare earth element includes at least one of Gd, Y, Er, and Nd; (2) The thickness of the magnesium-lithium alloy billet is 1.5t~5t, where t is the target wall thickness of the magnesium-lithium alloy thin-walled tube; (3) The height of the magnesium-lithium alloy billet is greater than 1.5 times the thickness of the spinning wheel.

7. The method for preparing the magnesium-lithium alloy thin-walled tube according to any one of claims 1 to 6, characterized in that, The preparation method further includes the following steps: The material obtained by spinning is then subjected to spinning shaping treatment.

8. The method for preparing the magnesium-lithium alloy thin-walled tube according to claim 7, characterized in that, It satisfies at least one of the following characteristics (1) to (3): (1) In the spinning and shaping process, the pressing amount is 0.5mm~1mm; (2) In the spinning and shaping process, the spindle speed is 10 rpm to 30 rpm; (3) In the spinning and shaping process, the feed speed is 1mm / s to 10mm / s.

9. A magnesium-lithium alloy thin-walled tube prepared by the method for preparing magnesium-lithium alloy thin-walled tubes as described in any one of claims 1 to 8.

10. The magnesium-lithium alloy thin-walled tube according to claim 9, characterized in that, It satisfies at least one of the following characteristics (1) to (2): (1) The outer diameter of the magnesium-lithium alloy thin-walled tube is Φ50mm~250mm; (2) The wall thickness of the magnesium-lithium alloy thin-walled tube is 1mm~5mm.

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