A forming method of an aluminum / magnesium / aluminum laminated composite shell with grid ribs

Abstract

The application provides a forming method of an aluminum / magnesium / aluminum layered composite shell with grid ribs, and belongs to the technical field of non-ferrous metal preparation. According to the performance characteristics of aluminum alloy and magnesium alloy materials, a threaded groove structure is processed on the inner and outer surfaces of the intermediate layer magnesium alloy cylinder, a magnesium / aluminum composite shell of outer layer magnesium alloy and inner layer aluminum alloy is formed by high-energy ultrasonic assisted internal spinning, the high-energy ultrasonic is beneficial to the plastic deformation of the inner aluminum alloy, reduces the internal residual stress, and realizes the three-dimensional occlusion between magnesium and aluminum. Through current assisted external spinning, the outer layer aluminum alloy is formed on the outer surface of the magnesium / aluminum composite shell, the energy generated by the current assistance is beneficial to the plastic deformation of the magnesium alloy and the aluminum alloy, the forming of the inner rib of the shell is realized through the grid groove structure on the surface of the outer spinning machine core mold, and the pressure bearing strength of the shell is improved.

Description

Technical Field

[0001] This invention belongs to the technical field of non-ferrous metal preparation, and specifically discloses a method for forming a layered composite shell of aluminum / magnesium / aluminum with mesh reinforcement. Background Technology

[0002] Magnesium alloys possess low density, high specific strength, and excellent electromagnetic shielding properties, making them promising for applications in aerospace, weaponry, and electromagnetic shielding. However, their close-packed hexagonal crystal structure results in poor plasticity, making them prone to cracking during deformation. Furthermore, magnesium alloys are not corrosion-resistant, which limits their applications to some extent. In contrast, aluminum alloys offer superior plastic deformation capabilities and excellent corrosion resistance, compensating for the shortcomings of magnesium alloys. Therefore, developing magnesium-aluminum composite materials is a future trend for lightweight components.

[0003] Magnesium-aluminum layered composite shell components are fabricated, with aluminum alloy for the inner and outer layers and magnesium alloy for the middle layer. The aluminum alloy in the inner and outer layers can improve the corrosion resistance of the shell. During the thermoforming process of the aluminum / magnesium / aluminum composite shell, brittle intermetallic compounds are easily formed at the magnesium-aluminum interface, which reduces the interfacial bonding strength and affects the overall performance of the shell. How to obtain a high-performance interface is an urgent problem to be solved in the fabrication of magnesium-aluminum composite shell components.

[0004] To improve the shell's ability to withstand external pressure, internal ribs are usually added inside the shell by welding. However, the process of welding internal ribs can easily cause shell deformation, reduce the mechanical and corrosion resistance of the welded parts, and affect the overall performance of the shell. Summary of the Invention

[0005] This invention provides a method for forming a layered aluminum / magnesium / aluminum composite shell with mesh reinforcement, to overcome the following technical problems:

[0006] 1. During the hot forming of aluminum / magnesium / aluminum composite shells, brittle intermetallic compounds are easily formed at the magnesium-aluminum interface, resulting in a decrease in interfacial bonding strength.

[0007] 2. The process of welding and adding internal ribs can easily cause shell deformation, reduce the mechanical and corrosion resistance of the welded parts, and affect the overall performance of the shell.

[0008] The forming method of the above-mentioned aluminum / magnesium / aluminum layered composite shell with mesh reinforcement includes the following steps:

[0009] S1, for machining aluminum alloy inner cylinders, magnesium alloy intermediate cylinders, and aluminum alloy outer cylinders.

[0010] The aluminum alloy inner cylinder, magnesium alloy intermediate cylinder and aluminum alloy outer cylinder are machined to the preset size. Threaded grooves are machined on the inner and outer surfaces of the magnesium alloy intermediate cylinder, and a step is machined at the first end of the aluminum alloy inner cylinder.

[0011] S2, the aluminum alloy inner cylinder is assembled into the magnesium alloy intermediate cylinder, and the step at the first end of the aluminum alloy inner cylinder presses against the first end of the magnesium alloy intermediate cylinder to form a magnesium / aluminum assembly.

[0012] S3, High-energy ultrasonic-assisted spinning forming of magnesium / aluminum composite shell

[0013] The magnesium / aluminum assembly prepared in step S2 is mounted on an internal spinning press and spun into shape, while being subjected to ultrasonic vibration.

[0014] S4, After mechanically removing the stepped portion of the magnesium / aluminum composite shell prepared in step S3, the shell is closed.

[0015] S5, current-assisted spinning of aluminum / magnesium / aluminum composite shell

[0016] The magnesium / aluminum composite shell prepared in step S4 is installed inside the aluminum alloy outer cylinder to form an aluminum / magnesium / aluminum assembly. Then, it is installed on an external spinning press for spinning and forming, while pulse heating is performed. The surface of the core mold of the external spinning press is provided with a grid groove.

[0017] The internal spinning press used in step S3 includes an internal spinning press frame, a fixed frame, a sliding frame, a three-jaw chuck, an internal spinning press spindle, an internal spinning press motor, a retaining ring, an ultrasonic generator, a transducer, an amplitude transformer, an ultrasonic tool head, and a spinning head. The fixed frame and the sliding frame are arranged opposite to each other. The fixed frame is fixedly installed on the internal spinning press frame, and the sliding frame is slidably installed on the internal spinning press frame. The three-jaw chuck is installed on the fixed frame. The internal spinning press spindle is installed on the sliding frame and is coaxially arranged with the three-jaw chuck, and is driven to rotate by the internal spinning press motor. A fixed ring is installed inside the internal spinning press spindle. The device consists of a ring; a transducer mounted on a fixed ring, coaxially aligned with the main shaft of the internal spinning machine, with its input end connected to the output end of the ultrasonic generator; an amplitude transformer with its input end connected to the output end of the transducer; an ultrasonic tool head passing through the main shaft of the internal spinning machine, with its input end connected to the output end of the amplitude transformer; a spinning head comprising an inner ring and cylindrical rolling elements; the inner ring of the spinning head having a frustum-shaped structure, with its central hole connected to the output end of the ultrasonic tool head, its small end face facing the fixed frame, and its large end face facing the sliding frame; and cylindrical rolling elements surrounding the outer side of the inner ring of the spinning head, with its central axis parallel to the outer wall of the inner ring.

[0018] Step S3 includes:

[0019] t1, clamp the second end of the magnesium / aluminum assembly onto the three-jaw chuck, align the centerline of the magnesium / aluminum assembly with the centerline of the spindle of the internal spinning press, and then position and clamp the magnesium / aluminum assembly.

[0020] t2, turn on the internal spinning press, feed the spindle of the internal spinning press, and the ultrasonic tool head drives the cylindrical rolling body to spin the magnesium / aluminum assembly while performing ultrasonic vibration.

[0021] In the aforementioned internal spinning press, the output end of the ultrasonic tool head is provided with a tool thread; the inner ring of the spinning head is fitted on the tool thread; the spinning head also includes a retainer, which passes through the cylindrical rolling element and has its two ends connected to the outer wall of the inner ring of the spinning head and the tool thread, respectively; a washer and a locking nut are fitted on the tool thread to press the retainer.

[0022] The aforementioned internal spinning press also includes an internal spinning press guide rail; the internal spinning press guide rail is mounted on the internal spinning press frame; the sliding frame is mounted on the internal spinning press guide rail; the internal spinning press is controlled by the internal spinning press electrical control cabinet.

[0023] The external spinning press used in step S5 includes an external spinning press frame, a protective cover, an external spinning press spindle, an external spinning press motor, a clamping and positioning device, an external spinning press mandrel, a tailstock, a hydraulic cylinder, a spinning assembly, and a high-frequency pulse power supply; the protective cover is installed on the external spinning press frame; the external spinning press spindle, clamping and positioning device, external spinning press mandrel, spinning assembly, and tailstock are all located inside the protective cover; the external spinning press spindle is rotatably mounted on the protective cover and driven to rotate by the external spinning press motor; the external spinning press mandrel is installed on the external spinning press spindle through the clamping and positioning device and connected to the high-frequency pulse power supply; the external spinning press mandrel, clamping and positioning device, and external spinning press spindle are coaxially arranged; the tailstock... The top is mounted on the protective cover and is coaxially arranged with the outer spinning press core mold. It is driven by a hydraulic cylinder to move axially. The spinning assembly includes a spinning wheel support platform, a first spinning wheel support frame, a second spinning wheel support frame, a third spinning wheel support frame, a first spinning wheel, a second spinning wheel, and a third spinning wheel. The spinning wheel support platform is slidably mounted on the outer spinning press frame. The first spinning wheel support frame, the second spinning wheel support frame, and the third spinning wheel support frame are fixedly mounted on the spinning wheel support platform. The first spinning wheel, the second spinning wheel, and the third spinning wheel are rotatably mounted on the first spinning wheel support frame, the second spinning wheel support frame, and the third spinning wheel support frame, respectively. The three spinning wheels are distributed at 120°. The spinning wheels are connected to a high-frequency pulse power supply.

[0024] Step S5 includes:

[0025] t1, The aluminum / magnesium / aluminum assembly is fitted onto the outer spinning die;

[0026] t2, start the external spinning press, so that the three rollers of the external spinning press are fed axially. At the same time, the aluminum / magnesium / aluminum assembly-external spinning press core mold-roller-high frequency pulse power supply form a closed loop for pulse heating.

[0027] In the aforementioned external spinning press, the external spinning press core mold includes a core mold and multiple segmented molds assembled outside the core mold; the multiple segmented molds include narrow segmented molds and wide segmented molds, which are arranged alternately; the surface of the segmented molds is provided with grid grooves; a clamping positioner is sleeved on the multiple segmented molds to connect the segmented molds and the core mold into a whole.

[0028] In the aforementioned external spinning press, the first spinning wheel support frame, the second spinning wheel support frame, and the third spinning wheel support frame are respectively provided with a first spinning wheel shaft, a second spinning wheel shaft, and a third spinning wheel shaft; the spinning wheel is rotatably mounted on the spinning wheel shaft and is positioned and locked by the spinning wheel retaining ring.

[0029] The aforementioned external spinning press also includes an external spinning press guide rail; the external spinning press guide rail is mounted on the external spinning press frame; the spinning wheel support platform is mounted on the external spinning press guide rail; the external spinning press is controlled by the external spinning press electrical control cabinet.

[0030] In step S3, the spinning deformation amount is 30%;

[0031] The ultrasonic output power is 150W, and the frequency is 20kHz.

[0032] In step S5, the total spinning deformation is 40%, and the spinning is performed in one pass.

[0033] The pulse current density is 25–30 A / mm. 2 The pulse current frequency is 1000-1200Hz.

[0034] In step S1, the machining steps of the aluminum alloy inner cylinder are as follows: clamp the aluminum alloy inner cylinder on a lathe, turn the outer surface with an outer diameter of 100mm, an upper deviation of -0.05mm, a lower deviation of -0.15mm, an inner diameter of 96mm, an upper deviation of 0.1mm, and a lower deviation of 0, and machine a step at the first end with an outer diameter of 115mm and a thickness of 4mm.

[0035] The machining steps for the magnesium alloy intermediate cylinder are as follows: clamp the magnesium alloy intermediate cylinder on a machine tool, and machine a threaded groove on the inner surface. The inner diameter is 100mm, the upper deviation is 0.1mm, the lower deviation is 0, the threaded groove depth is 0.2mm, the bottom width of the threaded groove is 1mm, the side angle of the threaded groove is 30°, and the threaded groove spacing is 3mm.

[0036] A threaded groove is machined on the outer surface with an outer diameter of 120 mm, an upper deviation of 0.1 mm, a lower deviation of 0 mm, a groove depth of 0.2 mm, a bottom width of 1 mm, a side angle of 30°, and a groove spacing of 3 mm.

[0037] The machining steps for the aluminum alloy outer cylinder are as follows: clamp the aluminum alloy outer cylinder on a lathe, machine the inner surface, with an inner diameter of 120mm, an upper deviation of 0.1mm, a lower deviation of 0, and an outer diameter of 130mm.

[0038] In step S4, the closing angle is 30°;

[0039] In step S5, the external spinning press core mold is made of H13 steel;

[0040] The depth of the grid groove is 4mm, the bottom width of the grid groove is 2.5mm, the side angle of the grid groove is 30°, and the spacing between the grid grooves is 20mm.

[0041] The present invention has the following beneficial effects:

[0042] This invention addresses the performance characteristics of aluminum and magnesium alloys. It involves machining threaded grooves on the inner and outer surfaces of a magnesium alloy intermediate cylinder, and then using high-energy ultrasonic-assisted internal spinning to form a magnesium / aluminum composite shell with an outer magnesium alloy layer and an inner aluminum alloy layer. The high-energy ultrasound facilitates the plastic deformation of the aluminum alloy inner cylinder, reducing internal residual stress and achieving three-dimensional interlocking between the magnesium and aluminum. An external spinning method using electric current is used to form the outer aluminum alloy layer on the outer surface of the magnesium / aluminum composite shell. The energy generated by the electric current facilitates the plastic deformation of both the magnesium and aluminum alloys. The grid groove structure on the surface of the external spinning die forms the internal ribs of the shell, improving its compressive strength. Attached Figure Description

[0043] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the structure of a magnesium alloy intermediate cylinder;

[0045] Figure 2 for Figure 1 A magnified view of a portion of the image;

[0046] Figure 3 A schematic diagram of the spinning process for a high-energy ultrasonic-assisted magnesium / aluminum composite shell;

[0047] Figure 4 A schematic diagram of the spinning process for an electric current-assisted aluminum / magnesium / aluminum composite shell;

[0048] Figure 5 This is an assembly diagram of the external spinning press core mold;

[0049] Figure 6 This is an exploded view of the external spinning press core mold;

[0050] Figure 7 This is a schematic diagram of a layered composite shell with a mesh reinforcement of aluminum / magnesium / aluminum.

[0051] In the diagram: 101-Internal spinning press frame; 102-Internal spinning press guide rail; 103-Fixed frame; 104-Sliding frame; 105-Three-jaw chuck; 106-Internal spinning press spindle; 107-Internal spinning press motor; 108-Fixed ring; 109-Ultrasonic generator; 110-Transducer; 111-Amplitude rod; 112-Ultrasonic tool head; 113-Spinning head inner ring; 114-Cage; 115-Cylindrical rolling element; 116-Washer; 117-Locking nut; 118- Internal spinning press electrical control cabinet; 119-Internal spinning press power switch; 120-Internal spinning press power switch indicator light; 121-Spindle control switch; 122-Spindle control switch indicator light; 123-Ultrasonic generator power switch; 124-Ultrasonic generator power indicator light; 125-Ultrasonic power control knob; 126-Ultrasonic power control indicator light; 127-Ultrasonic amplitude control knob; 128-Ultrasonic amplitude control indicator light; 129-Internal spinning press display screen; 130-Flange;

[0052] 201-External spinning press frame; 202-Protective cover; 203-External spinning press guide rail; 204-External spinning press main shaft; 205-External spinning press motor; 206-Clamping positioner; 207-External spinning press core mold; 208-Tail top; 209-Hydraulic cylinder; 210-High frequency pulse power supply; 211-Spinning wheel support platform; 212-First spinning wheel support; 213-First spinning wheel shaft; 214-First spinning wheel retaining ring; 215-First spinning wheel; 216-Second spinning wheel support frame; 217-Second spinning wheel shaft; 218-Second spinning wheel retaining ring; 219-Second spinning wheel; 220-Third spinning wheel support frame; 221-Third 222-Third spinning wheel shaft; 223-Third spinning wheel; 224-External spinning press electrical control cabinet; 225-External spinning press power switch; 226-External spinning press power switch indicator light; 227-Core mold control switch; 228-Core mold control switch indicator light; 229-Tail top control switch; 230-Tail top control switch indicator light; 231-Spinning wheel control switch; 232-Spinning wheel control switch indicator light; 233-High frequency pulse power switch; 234-High frequency pulse power switch indicator light; 235-High frequency pulse control switch; 236-High frequency pulse control switch indicator light; 237-External spinning press display screen;

[0053] 207.1 - Mold core; 207.2 - Narrow segmented mold; 207.3 - Wide segmented mold; 207.4 - Mesh groove;

[0054] 301 - Aluminum alloy inner cylinder; 302 - Magnesium alloy intermediate cylinder; 303 - Aluminum alloy outer cylinder. Detailed Implementation

[0055] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Among various metal shell forming methods, spinning has the advantages of high component forming accuracy, the ability to form thin-walled components, and material saving. By rationally designing the mandrel structure used in the spinning process, shell components with internal ribs can be produced, avoiding the impact on the structural integrity of the shell due to subsequent welding to reinforce the internal ribs.

[0057] In the spinning process, heating is usually required to improve the plasticity of the blank, such as flame heating or electromagnetic induction heating. However, when using flame or electromagnetic induction heating, the heating range of the blank is relatively large, which can easily cause deterioration of the internal structure of the blank and reduce the mechanical properties of the component. Based on the characteristics of ultrasound and electric current, coupling ultrasound with electric current can achieve localized heating during the spinning process, improving the plastic deformation capacity of the metal at a lower temperature and reducing residual stress inside the component.

[0058] Based on the above analysis, using magnesium alloy as the intermediate layer material and aluminum alloy as the inner and outer layers of the shell, with pre-fabricated threaded groove structures on the inner and outer surfaces of the intermediate magnesium alloy layer, and aluminum alloy filling into the threaded grooves during the spinning process, a three-dimensional interface of mechanical interlocking is formed between magnesium and aluminum, improving the interface shear strength. Applying ultrasonic energy field and electric field during the spinning process improves the plastic deformation capacity of the metal and reduces the residual stress inside the shell component. Through the grid grooves on the surface of the spinning mandrel, a grid rib structure is formed on the inner surface of the inner aluminum alloy layer, improving the composite shell's ability to withstand external pressure. This method can produce high-performance aluminum / magnesium / aluminum layered composite shell components.

[0059] This embodiment considers the performance advantages of magnesium and aluminum alloys, using lightweight, high-strength magnesium alloy as the intermediate layer metal and high-strength, corrosion-resistant aluminum alloy as the inner and outer layer metals. An ultrasonic / current-assisted spinning process is employed to form a three-dimensional aluminum / magnesium / aluminum layered composite shell component with a mesh-like internal rib. The composite shell component is lightweight, high-strength, and corrosion-resistant. The interface is a mechanically interlocking three-dimensional interface. Ultrasonic / current stimulation promotes metallurgical bonding at the interface, improves the plastic deformation capacity of the magnesium and aluminum alloys, and reduces residual stress within the shell component. By designing a spinning mandrel with mesh grooves, a mesh rib structure can be formed inside the shell, increasing its compressive strength. This is a practical method for preparing layered composite shell components. The raw materials used are: aluminum alloy cylinder, magnesium alloy cylinder, sandpaper, and alcohol, with the following quantities measured in pieces, millimeters, and sheets.

[0060]

[0061] It is formed by spinning using an internal spinning press and an external spinning press.

[0062] The internal spinning press includes an internal spinning press frame 101, an internal spinning press guide rail 102, a fixed frame 103, a sliding frame 104, a three-jaw chuck 105, an internal spinning press spindle 106, an internal spinning press motor 107, a retaining ring 108, an ultrasonic generator 109, a transducer 110, an amplitude transformer 111, an ultrasonic tool head 112, and a spinning head; the internal spinning press guide rail 102 is mounted on the internal spinning press frame 101; the fixed frame 103 and the sliding frame 104 are arranged opposite to each other, and the fixed frame 103 is fixed... The internal spinning press is fixedly mounted on the frame 101, and the sliding frame 104 is mounted on the internal spinning press guide rail 102; the three-jaw chuck 105 is mounted on the fixed frame 103; the first end of the internal spinning press main shaft 106 is mounted on the sliding frame 104, and the second end is mounted on the flange 130 by bolts and nuts. The internal spinning press main shaft 106 and the three-jaw chuck 105 are coaxially arranged and driven to rotate by the internal spinning press motor 107; a retaining ring 108 is installed inside the internal spinning press main shaft 106; the transducer 110 is installed. Mounted on the retaining ring 108, coaxially arranged with the spindle 106 of the internal spinning press, the input end of which is connected to the output end of the ultrasonic generator 109; the input end of the amplitude transformer 111 is connected to the output end of the transducer 110; the ultrasonic tool head 112 passes through the spindle 106 and flange 130 of the internal spinning press, the input end of which is connected to the output end of the amplitude transformer 111, and the output end is provided with a tool thread; the spinning head includes an inner ring 113, a cage 114, and cylindrical rolling elements 115; the inner ring 113 of the spinning head is circular. The structure is truncated, with a central hole connected to the tool thread of the ultrasonic tool head 112. The small end face faces the fixed frame 103, and the large end face faces the sliding frame 104. The cylindrical rolling element 115 surrounds the outer side of the inner ring 113 of the spinning head, with the central axis parallel to the outer wall of the inner ring 113 of the spinning head. The retainer 114 passes through the cylindrical rolling element 115, and its two ends are respectively connected to the outer wall of the inner ring 113 of the spinning head and the tool thread. A washer 116 and a locking nut 117 are fitted on the tool thread to press the retainer 114.

[0063] The internal spinning press is controlled by the internal spinning press electrical control cabinet 118. The internal spinning press electrical control cabinet 118 is equipped with an internal spinning press power switch 119, an internal spinning press power switch indicator light 120, a spindle control switch 121, a spindle control switch indicator light 122, an ultrasonic generator power switch 123, an ultrasonic generator power indicator light 124, an ultrasonic power control knob 125, an ultrasonic power control indicator light 126, an ultrasonic amplitude control knob 127, an ultrasonic amplitude control indicator light 128, and an internal spinning press display screen 129.

[0064] The external spinning press includes an external spinning press frame 201, a protective cover 202, an external spinning press guide rail 203, an external spinning press spindle 204, an external spinning press motor 205, a clamping and positioning device 206, an external spinning press mandrel 207, a tail fin 208, a hydraulic cylinder 209, spinning components, and a high-frequency pulse power supply 210; the protective cover 202 is mounted on the external spinning press frame 201; the external spinning press guide rail 203, external spinning press spindle 204, clamping and positioning device 206, external spinning press mandrel 207, spinning components, and tail fin 208 are all located inside the protective cover 202; the external spinning press guide rail 203 is mounted on... The external spinning press is mounted on the frame 201; the main shaft 204 of the external spinning press is rotatably mounted on the protective cover 202 and driven to rotate by the external spinning press motor 205; the core mold 207 of the external spinning press is mounted on the main shaft 204 of the external spinning press via a clamping positioner 206 and is connected to a high-frequency pulse power supply 210; the core mold 207, the clamping positioner 206, and the main shaft 204 of the external spinning press are coaxially arranged; the tail fin 208 is mounted on the protective cover 202 and coaxially arranged with the core mold 207 of the external spinning press, and is driven to move axially by a hydraulic cylinder 209; the spinning assembly includes a spinning wheel support platform 211 and a first spinning wheel support frame 211. 12. First spinning wheel shaft 213, first spinning wheel retaining ring 214, first spinning wheel 215, second spinning wheel support frame 216, second spinning wheel shaft 217, second spinning wheel retaining ring 218, second spinning wheel 219, third spinning wheel support frame 220, third spinning wheel shaft 221, third spinning wheel retaining ring 222, third spinning wheel 223; Spinning wheel support platform 211 is mounted on the outer spinning press guide rail 203; First spinning wheel support frame 212, second spinning wheel support frame 216, and third spinning wheel support frame 220 are fixedly mounted on spinning wheel support platform 211; First spinning wheel support frame 212, second spinning wheel support frame 216 The third rotating wheel support frame 220 is respectively provided with a first rotating wheel shaft 213, a second rotating wheel shaft 217 and a third rotating wheel shaft 218; the first rotating wheel 215, the second rotating wheel 219 and the third rotating wheel 223 are respectively rotatably mounted on the first rotating wheel shaft 213, the second rotating wheel shaft 217 and the third rotating wheel shaft 218, and are positioned and locked by rotating wheel retaining rings. The three rotating wheels are distributed at 120°. The rotating wheels are connected to the high-frequency pulse power supply 210. In this embodiment, the first rotating wheel shaft 213 is connected to the high-frequency pulse power supply 210 through a wire to realize the electrical connection between the first rotating wheel 215 and the high-frequency pulse power supply 210.

[0065] In the aforementioned external spinning press, the core mold 207 includes a core mold 207.1 and multiple segmented molds assembled outside the core mold 207.1. The multiple segmented molds include narrow segmented molds 207.2 and wide segmented molds 207.3. The width of the narrow segmented mold 207.2 is smaller than the width of the wide segmented mold 207.3. The narrow segmented molds 207.2 and wide segmented molds 207.3 are staggered for easy demolding. The surface of the segmented molds is provided with grid grooves 207.4. A clamping and positioning device 206 is sleeved on the multiple segmented molds to connect the segmented molds to the core mold 207.1 into a whole. In this embodiment, the segmented molds include three narrow segmented molds 207.2 and three wide segmented molds 207.3.

[0066] The external spinning press is controlled by the external spinning press electrical control cabinet 224. The external spinning press electrical control cabinet 224 is equipped with an external spinning press power switch 225, an external spinning press power switch indicator light 226, a core mold control switch 227, a core mold control switch indicator light 228, a tail top control switch 229, a tail top control switch indicator light 230, a spinning wheel control switch 231, a spinning wheel control switch indicator light 232, a high-frequency pulse power switch 233, a high-frequency pulse power switch indicator light 234, a high-frequency pulse control switch 235, a high-frequency pulse control switch indicator light 236, and an external spinning press display screen 237.

[0067] The forming method of the above-mentioned aluminum / magnesium / aluminum layered composite shell with mesh reinforcement includes the following steps.

[0068] S1, machining the aluminum alloy inner cylinder 301, the magnesium alloy intermediate cylinder 302, and the aluminum alloy outer cylinder 303.

[0069] The machining steps of the aluminum alloy inner cylinder 301 are as follows: the aluminum alloy inner cylinder 301 is clamped on the lathe by a three-jaw chuck, and the outer surface is machined with an outer diameter of 100mm, an upper deviation of -0.05mm, a lower deviation of -0.15mm, an inner diameter of 96mm, an upper deviation of 0.1mm, and a lower deviation of 0. A step is machined at the first end with an outer diameter of 115mm and a thickness of 4mm.

[0070] The machining steps of the magnesium alloy intermediate cylinder 302 are as follows: the magnesium alloy intermediate cylinder 302 is clamped on the machine tool by a three-jaw chuck, and a thread groove is machined on the inner surface. The inner diameter is 100mm, the upper deviation is 0.1mm, the lower deviation is 0, the thread groove depth is 0.2mm, the bottom width of the thread groove is 1mm, the side angle of the thread groove is 30°, and the thread groove spacing is 3mm.

[0071] A threaded groove is machined on the outer surface with an outer diameter of 120 mm, an upper deviation of 0.1 mm, a lower deviation of 0 mm, a groove depth of 0.2 mm, a bottom width of 1 mm, a side angle of 30°, and a groove spacing of 3 mm.

[0072] The machining steps for the aluminum alloy outer cylinder 303 are as follows: the aluminum alloy outer cylinder 303 is clamped on a lathe using a three-jaw chuck, and the inner surface is machined with an inner diameter of 120mm, an upper deviation of 0.1mm, a lower deviation of 0, and an outer diameter of 130mm.

[0073] S2, the aluminum alloy inner cylinder 301 is assembled into the magnesium alloy intermediate cylinder 302 to form a magnesium / aluminum assembly. The step at the first end of the aluminum alloy inner cylinder 301 presses against the first end of the magnesium alloy intermediate cylinder 302 for positioning, while preventing coolant from entering the connection interface and affecting the interface connection performance.

[0074] S3, High-energy ultrasonic-assisted spinning forming of magnesium / aluminum composite shell

[0075] t1, clamp the second end of the magnesium / aluminum assembly onto the three-jaw chuck 105, so that the center line of the magnesium / aluminum assembly coincides with the center line of the spindle 106 of the internal spinning press. After adjustment, position and clamp the magnesium / aluminum assembly.

[0076] t2, turn on the internal spinning press, feed the spindle 106 of the internal spinning press, and the ultrasonic tool head 112 drives the cylindrical rolling body 115 to spin the magnesium / aluminum assembly while performing ultrasonic vibration. The spinning deformation is 30%, the ultrasonic output power is 150W, and the frequency is 20kHz.

[0077] t3, After spinning is completed, turn off the inner spinning press and remove the spun magnesium / aluminum composite shell.

[0078] S4. After mechanically removing the stepped portion of the magnesium / aluminum composite shell prepared in step S3, the shell is closed at a closing angle of 30° to prepare for the next process.

[0079] S5, current-assisted spinning of aluminum / magnesium / aluminum composite shell

[0080] The external spinning press core mold 207 is made of H13 steel; the mesh groove 207.4 has a depth of 4mm, a bottom width of 2.5mm, a side angle of 30°, and a spacing of 20mm.

[0081] t1, wipe the threaded grooves on the outer surface of the magnesium / aluminum composite shell prepared in step S4 with alcohol to remove impurities on the surface, install it in the aluminum alloy outer cylinder 303 to assemble it into an aluminum / magnesium / aluminum assembly, and then put it on the outer spinning press core mold 207.

[0082] t2, start the external spinning press, allowing the three rollers of the external spinning press to feed axially. Simultaneously, the aluminum / magnesium / aluminum assembly - external spinning press mandrel - rollers - high-frequency pulse power supply form a closed loop for pulse heating. The total spinning deformation is 40%, and the spinning is completed in one pass. The pulse current density is 25-30 A / mm. 2The pulse current frequency is 1000–1200 Hz;

[0083] t3, shut down the external spinning press, remove the external spinning press core mold 207, disassemble the external spinning press core mold 207, and complete the spinning forming of the aluminum / magnesium / aluminum layered composite shell with grid ribs.

[0084] S6, Storage

[0085] The prepared aluminum / magnesium / aluminum layered composite shell with mesh reinforcement is packaged with soft material and stored in a clean, dry environment, protected from moisture, sunlight, and acid, alkali and salt corrosion. The storage temperature is 20℃ and the relative humidity is ≤10%.

[0086] Conclusion: The shell uses aluminum alloy as the inner and outer layer material and magnesium alloy as the intermediate layer material to achieve the purpose of lightweight, high strength and corrosion resistance. The inner and outer surfaces of the magnesium alloy intermediate cylinder 302 are pre-formed with threaded groove structures. During the forming process, aluminum alloy is filled into the threaded grooves to realize the three-dimensional interlocking interface between aluminum and magnesium, which increases the interfacial bonding shear strength. During the inner spinning process, high-energy ultrasonic waves are applied to the cylindrical rolling element 115 to promote the plastic flow of the inner aluminum alloy and reduce the deformation resistance. During the outer spinning process of forming the inner ribs, pulsed current is applied to raise the local temperature and improve the metal fluidity of magnesium alloy and aluminum alloy, which is beneficial to the forming of the inner ribs and promotes the metallurgical bonding of magnesium / aluminum interface. A high-performance aluminum / magnesium / aluminum layered composite shell component is prepared.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for forming a layered composite shell of aluminum / magnesium / aluminum with mesh reinforcement, characterized in that, Includes the following steps: S1, for machining aluminum alloy inner cylinders, magnesium alloy intermediate cylinders, and aluminum alloy outer cylinders. The aluminum alloy inner cylinder, magnesium alloy intermediate cylinder and aluminum alloy outer cylinder are machined to the preset size. Threaded grooves are machined on the inner and outer surfaces of the magnesium alloy intermediate cylinder, and a step is machined at the first end of the aluminum alloy inner cylinder. S2, the aluminum alloy inner cylinder is assembled into the magnesium alloy intermediate cylinder, and the step at the first end of the aluminum alloy inner cylinder presses against the first end of the magnesium alloy intermediate cylinder to form a magnesium / aluminum assembly. S3, High-energy ultrasonic-assisted spinning forming of magnesium / aluminum composite shell The magnesium / aluminum assembly prepared in step S2 is mounted on an internal spinning press and spun into shape, while being subjected to ultrasonic vibration. Step S3 includes: t1, clamp the second end of the magnesium / aluminum assembly onto the three-jaw chuck, align the centerline of the magnesium / aluminum assembly with the centerline of the spindle of the internal spinning press, and then position and clamp the magnesium / aluminum assembly. t2, turn on the internal spinning press, feed the spindle of the internal spinning press, and the ultrasonic tool head drives the cylindrical rolling body to spin the magnesium / aluminum assembly while performing ultrasonic vibration; In step S3, the spinning deformation is 30%; The ultrasonic output power is 150W, and the frequency is 20kHz. S4, After mechanically removing the stepped portion of the magnesium / aluminum composite shell prepared in step S3, the shell is closed. S5, current-assisted spinning of aluminum / magnesium / aluminum composite shell The magnesium / aluminum composite shell prepared in step S4 is installed inside the aluminum alloy outer cylinder to form an aluminum / magnesium / aluminum assembly. Then, it is installed on an external spinning press for spinning and forming, while pulse heating is performed. The surface of the core mold of the external spinning press is provided with a grid groove. The external spinning press core mold includes a core mold and multiple segmented molds assembled outside the core mold; The multi-segmented mold includes narrow segmented molds and wide segmented molds, which are arranged alternately. The surface of the segmented mold is provided with mesh grooves; The clamping and positioning device is sleeved on the outside of multiple segmented molds to connect the segmented molds and the mold core into a whole; Step S5 includes: t1, The aluminum / magnesium / aluminum assembly is fitted onto the outer spinning die; t2, start the external spinning press, so that the three rollers of the external spinning press are fed axially. At the same time, the aluminum / magnesium / aluminum assembly-external spinning press core mold-roller-high frequency pulse power supply form a closed loop for pulse heating. In step S5, the total spinning deformation is 40%, and the spinning is performed in one pass. The pulse current density is 25–30 A / mm. 2 The pulse current frequency is 1000-1200Hz.

2. The forming method of the aluminum / magnesium / aluminum layered composite shell with mesh reinforcement according to claim 1, characterized in that, The internal spinning press used in step S3 includes an internal spinning press frame, a fixed frame, a sliding frame, a three-jaw chuck, an internal spinning press spindle, an internal spinning press motor, a fixed ring, an ultrasonic generator, a transducer, an amplitude transformer, an ultrasonic tool head, and a spinning head. The fixed frame and the sliding frame are arranged opposite to each other. The fixed frame is fixedly installed on the frame of the inner spinning press, and the sliding frame is slidably installed on the frame of the inner spinning press. The three-jaw chuck is mounted on a fixed frame; The main shaft of the internal spinning press is mounted on a sliding frame and coaxially arranged with the three-jaw chuck, and is driven to rotate by the internal spinning press motor. A retaining ring is installed inside the main shaft of the internal spinning press; The transducer is mounted on a fixed ring and is coaxially arranged with the main shaft of the internal spinning press. Its input end is connected to the output end of the ultrasonic generator. The input end of the amplitude transformer is connected to the output end of the transducer; The ultrasonic tool head passes through the main shaft of the internal rotary press, and its input end is connected to the output end of the amplitude transformer. The spinning head includes a spinning head inner ring and a cylindrical rolling element; The inner ring of the spinning head is a frustum-shaped structure, with the central hole connected to the output end of the ultrasonic tool head. The small end face faces the fixed frame, and the large end face faces the sliding frame. The cylindrical rolling element surrounds the outer side of the inner ring of the spinning head, with its central axis parallel to the outer wall of the inner ring of the spinning head.

3. The forming method of the aluminum / magnesium / aluminum layered composite shell with mesh reinforcement according to claim 2, characterized in that, The output end of the ultrasonic tool head is provided with a tool thread; The inner ring of the spinning head is fitted onto the tool thread; The spinning head also includes a cage that passes through the cylindrical rolling element and has its two ends connected to the outer wall of the inner ring of the spinning head and the tool thread, respectively. The tool thread is fitted with a washer and a lock nut to compress and retain the retainer.

4. The forming method of the aluminum / magnesium / aluminum layered composite shell with mesh reinforcement according to claim 3, characterized in that, The internal spinning press also includes an internal spinning press guide rail; The internal spinning press guide rail is mounted on the internal spinning press frame; The sliding frame is mounted on the guide rail of the internal spinning press; The internal spinning press is controlled by the internal spinning press electrical control cabinet.

5. The method for forming a mesh-ribbed aluminum / magnesium / aluminum layered composite shell according to any one of claims 1-4, characterized in that, The external spinning press used in step S5 includes an external spinning press frame, a protective cover, an external spinning press spindle, an external spinning press motor, a clamping and positioning device, an external spinning press core mold, a tail jack, a hydraulic cylinder, spinning components, and a high-frequency pulse power supply; The protective cover is installed on the frame of the external spinning press; The main shaft, clamping positioner, external spinning press core mold, spinning assembly, and tail top of the external spinning press are all located inside the protective cover; The main shaft of the external rotary press is rotatably mounted on the protective cover and is driven to rotate by the external rotary press motor. The external spinning press core mold is mounted on the external spinning press main shaft via a clamping positioner and is connected to a high-frequency pulse power supply. The external spinning press core mold, clamping positioner, and external spinning press main shaft are coaxially arranged. The tail top is mounted on the protective cover and is coaxially arranged with the outer spinning press core mold, and is driven by a hydraulic cylinder to move axially. The spinning assembly includes a spinning wheel support platform, a first spinning wheel support frame, a second spinning wheel support frame, a third spinning wheel support frame, a first spinning wheel, a second spinning wheel, and a third spinning wheel; The rotary support platform is slidably mounted on the frame of the external rotary press; The first, second, and third swivel support frames are fixedly installed on the swivel support platform. The first, second, and third rotating wheels are rotatably mounted on the first, second, and third rotating wheel support frames, respectively, with the three rotating wheels at a 120° angle. o The distribution wheel is connected to a high-frequency pulse power supply.

6. The forming method of the aluminum / magnesium / aluminum layered composite shell with mesh reinforcement according to claim 5, characterized in that, The first, second, and third rotating wheel support frames are respectively equipped with a first rotating wheel shaft, a second rotating wheel shaft, and a third rotating wheel shaft; The rotating wheel is mounted on the rotating wheel shaft and is positioned and locked by the rotating wheel retaining ring.

7. The forming method of the aluminum / magnesium / aluminum layered composite shell with mesh reinforcement according to claim 6, characterized in that, The external rotary press also includes the external rotary press guide rail; The guide rails of the external spinning press are mounted on the frame of the external spinning press; The spinning wheel support platform is mounted on the guide rail of the external spinning press; The external spinning press is controlled by the external spinning press electrical control cabinet.

8. The forming method of the aluminum / magnesium / aluminum layered composite shell with mesh reinforcement according to claim 1, characterized in that, In step S1, the machining steps of the aluminum alloy inner cylinder are as follows: clamp the aluminum alloy inner cylinder on a lathe, turn the outer surface with an outer diameter of 100mm, an upper deviation of -0.05mm, a lower deviation of -0.15mm, an inner diameter of 96mm, an upper deviation of 0.1mm, and a lower deviation of 0, and machine a step at the first end with an outer diameter of 115mm and a thickness of 4mm. The machining steps for the magnesium alloy intermediate cylinder are as follows: clamp the magnesium alloy intermediate cylinder on a machine tool, and machine a threaded groove on the inner surface. The inner diameter is 100mm, the upper deviation is 0.1mm, the lower deviation is 0, the threaded groove depth is 0.2mm, the bottom width of the threaded groove is 1mm, the side angle of the threaded groove is 30°, and the threaded groove spacing is 3mm. A threaded groove is machined on the outer surface with an outer diameter of 120 mm, an upper deviation of 0.1 mm, a lower deviation of 0 mm, a groove depth of 0.2 mm, a bottom width of 1 mm, a side angle of 30°, and a groove spacing of 3 mm. The machining steps for the aluminum alloy outer cylinder are as follows: clamp the aluminum alloy outer cylinder on a lathe, machine the inner surface, with an inner diameter of 120mm, an upper deviation of 0.1mm, a lower deviation of 0, and an outer diameter of 130mm. In step S4, the closing angle is 30°; In step S5, the external spinning press core mold is made of H13 steel; The depth of the grid groove is 4mm, the bottom width of the grid groove is 2.5mm, the side angle of the grid groove is 30°, and the spacing between the grid grooves is 20mm.

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