Magnesium alloy welding rod straightening device and method assisted by pulse current and ultrasonic vibration

Abstract

The invention discloses a pulse current and ultrasonic vibration assisted magnesium alloy welding rod straightening device and method. The pulse current and ultrasonic vibration assisted magnesium alloy welding rod straightening device comprises a limiting #-shaped wheel, a first roller electrode, an ultrasonic straightener, a second roller electrode and a tooth-shaped driving wheel which are sequentially arranged. The first roller electrode and the second roller electrode are powered by a pulse power supply; the ultrasonic straightener consists of an ultrasonic transducer and a straightener and is powered by a high-frequency alternating-current power supply; the tooth-shaped driving wheel provides power for straightening of the magnesium alloy welding rod. The pulse current is guided into the welding rod through the roller electrode, so that the friction loss is reduced while the roller is kept in close contact with the welding rod; the thermal effect generated by the current and the electroplastic effect synergistically improve the ductility of the material, internal stress is eliminated in combination with ultrasonic vibration, high-precision shape correction is achieved through the straightening rollers, and finally the straightness of the magnesium alloy welding rod is remarkably improved. While the straightening efficiency and the surface quality are improved, the machining stress and friction damage are effectively reduced, and wide engineering application value is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrode straightening, and in particular to a magnesium alloy electrode straightening device and method assisted by pulsed current and ultrasonic vibration. Background Art

[0002] Due to its characteristics such as low density, high specific strength and specific stiffness, and good electromagnetic shielding performance, magnesium alloys have broad application prospects in fields such as aerospace, the automotive industry, and electronic products. Laser wire additive manufacturing technology is an advanced manufacturing technology that uses a laser as a heat source to manufacture three-dimensional objects by adding materials layer by layer, with advantages such as high precision, high efficiency, and high material utilization rate. The diameter of the electrode raw materials used is usually 3.0 mm, and there are particularly high requirements for the straightness of the electrodes used. Magnesium has a close-packed hexagonal crystal structure, with a small number of slip systems at normal temperature and pressure, making it difficult to deform at normal temperature, and with large internal stresses after deformation, resulting in difficulties in preparing high-straightness magnesium alloy electrodes. Moreover, the elastic modulus of magnesium alloys is relatively low, only 45 GPa, which is significantly lower than that of other metal materials (such as steel and aluminum alloys), making magnesium alloys prone to springback after being subjected to external forces. Especially during the processing of magnesium alloy wires, the springback effect is likely to cause the wires to bend and deform, thereby affecting their dimensional accuracy and surface quality, and bringing many adverse effects to subsequent processing and applications. In addition, during the manufacturing, storage, transportation, and use of electrodes, they may be bent, twisted, etc. due to certain or multiple factors. These situations will not only lead to a decline in product quality but may also affect their normal use.

[0003] To solve these problems, it is necessary to straighten magnesium alloy electrodes. Currently, most straightening technologies are aimed at stainless steel electrodes. For example, CN117358852A discloses a stainless steel wire straightening device with an adjustment function, CN221848501U discloses a stainless steel wire drawing and straightening device, and CN221414824U discloses a wire straightening and detection device, which respectively include straightening dies for wires and corresponding straightening methods. Usually, during the straightening process, the electrodes will undergo varying degrees of bending deformation. However, magnesium alloys have characteristics such as poor plastic deformation ability and significant anisotropy, resulting in difficulties in bending deformation. If the deformation amount is insufficient, straightening cannot be achieved, and if the deformation amount is too large, fracture will occur. Therefore, the previous straightening methods are not suitable for straightening magnesium alloy electrodes, and a new straightening device and method are now needed to straighten magnesium alloy electrodes. Summary of the Invention

[0004] To solve the above problems, the present invention proposes a magnesium alloy electrode straightening device and method assisted by pulsed current and ultrasonic vibration, which combines the straightening of magnesium alloy electrodes, the thermal effect and electroplasticity of pulsed current, and the elimination of residual stress by ultrasonic vibration to improve the straightening efficiency of magnesium alloy electrodes.

[0005] The technical solution adopted by the present invention is as follows: a straightening device and method for magnesium alloy electrodes assisted by pulsed current and ultrasonic vibration, including a limiting cross wheel, a first roller electrode, an ultrasonic straightener, a second roller electrode, and a toothed driving wheel arranged in sequence; the first roller electrode and the second roller electrode are powered by a pulsed power supply; the ultrasonic straightener is powered by a high-frequency AC power supply; the toothed driving wheel provides power for straightening the magnesium alloy electrode.

[0006] Further, the roller electrode includes a roller frame, a conductive roller group, and an electrode; the roller frame is a hollow structure; the conductive roller group is horizontally fixed inside the roller frame through insulating ceramic bearings; the electrode is in contact with the conductive roller group; the roller frame is provided with an inlet guiding hole and an outlet guiding hole with insulation treatment relatively, and the inlet guiding hole and the outlet guiding hole are respectively located in the straightening direction of the conductive roller group; perforated insulating plates are arranged on both sides of the outside of the roller frame in the straightening direction.

[0007] Further, the ultrasonic straightener includes an ultrasonic transducer, an amplitude rod, and two groups of straightening roller wheels perpendicular to each other; the straightening roller wheels are fixed in the amplitude rod through bearings, and the ultrasonic transducer is arranged at the rear end of the amplitude rod.

[0008] Further, the straightening roller wheels adjust the roller gap through adjusting bolts on the amplitude rod.

[0009] Further, the electrode is reliably insulated from the roller frame.

[0010] The present invention also discloses a straightening method for magnesium alloy electrodes assisted by pulsed current and ultrasonic vibration. Using the above device, it includes the following steps: Step 1, set the parameters of the pulsed power supply and the high-frequency AC power supply; Step 2, adjust the roller gap of the ultrasonic straightener; Step 3, pass the magnesium alloy electrode to be straightened through the limiting cross wheel, the first roller electrode, the ultrasonic straightener, the second roller electrode, and the toothed driving wheel in sequence, so that it is in close contact with the toothed driving wheel; Step 4, set the rotation speed of the toothed driving wheel; Step 5, set the frequency, amplitude, and contact pressure of the ultrasonic transducer; Step 6, turn on the pulsed power supply, the high-frequency AC power supply, the toothed driving wheel, and the ultrasonic transducer, and start straightening the magnesium alloy electrode; Step 7, after straightening, obtain a magnesium alloy electrode with a straightness meeting the requirements.

[0011] Furthermore, the pulse current in step 1 is set to 10-20A, the pulse frequency is set to 200-800Hz, and the duty cycle is set to 10%-90% to ensure that the electrode temperature does not exceed 200°C during the straightening process; the frequency of the high-frequency AC current power supply is set to 20kHz.

[0012] Furthermore, in step 4, the rotation speed of the driving wheel is 20-50 r / min.

[0013] Furthermore, in step 5, the frequency of the ultrasonic transducer is 20-40 kHz, the amplitude is 10-30 μm, and the contact pressure is 0.1-2 MPa.

[0014] The beneficial effects produced by the present invention are: 1. In view of the high deformation resistance and low straightening efficiency of rare earth magnesium alloy, the present invention introduces pulse current and ultrasonic vibration in the straightening process, and comprehensively utilizes the relevant technical advantages of electroplasticity, thermal effect, electrode straightening and ultrasonic vibration to straighten the magnesium alloy electrode; in the straightening deformation process, under the action of electroplasticity and thermal effect of pulse current, the temperature of the electrode is maintained at about 200°C, which reduces the deformation resistance of the rare earth magnesium alloy electrode and improves its bending deformation ability; at the same time, under the action of ultrasonic vibration, the original residual stress of the magnesium alloy electrode and the residual internal stress generated during the straightening and cooling process are reduced, thereby improving the straightness of the electrode after straightening.

[0015] 2. The present invention adopts a roller electrode to connect the pulse power supply and the magnesium alloy welding rod, and stably and continuously transmits the pulse current to the magnesium alloy welding rod, and the roller and the welding rod always maintain close contact to avoid discharge between the welding rod and the roller to damage the welding rod surface; the use of the roller can improve the roundness and surface finish of the welding rod, improve the defects caused to the welding rod in the traditional straightening process, and ensure the continuous action of the pulse current during the straightening process; the present invention adopts an insulating ceramic bearing to fix the roller to withstand the heat load generated by the pulse current, thereby ensuring the service life of the roller; at the same time, the electrical insulation of the ceramic bearing is used to maintain reliable insulation between the roller and the roller frame, so that the pulse current is transmitted to the rare earth magnesium alloy welding rod, which plays a role of electroplasticity.

[0016] 3. The present invention introduces ultrasonic vibration in the process of straightening and deforming magnesium alloy welding rods, which reduces the residual stress generated in the magnesium alloy welding rod preparation process on the one hand, and reduces the residual internal stress generated by bending deformation and cooling during the straightening process of the magnesium alloy welding rod on the other hand, thereby significantly improving the straightness of the magnesium alloy welding rod after straightening. In addition, the present invention combines the amplitude rod of the ultrasonic transducer with the straightening roller, and an adjusting bolt is installed on the amplitude rod, which not only saves space, but also enables the ultrasonic straightener to be used for magnesium alloy welding rods with different degrees of bending under the adjustment of the adjusting nut.

[0017] In summary, the patented technology provides reliable technical support for the efficient straightening of rare earth magnesium alloy electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the overall structure of the device of the present invention; Figure 2 is a detailed structural diagram of the conductive roller of the present invention; Figure 3 is a detailed structural diagram of the ultrasonic straightener of the present invention; In the figure: 1-cross-shaped limit wheel, 2-first roller electrode, 3-ultrasonic straightener, 4-second roller electrode, 5-toothed driving wheel, 6-pulse power supply, 7-high-frequency AC power supply, 8-electrode, 9-inlet guiding hole, 10-roller frame, 11-conductive roller group, 12-wire, 13-insulating ceramic bearing, 14-outlet guiding hole, 15-insulating plate, 16-ultrasonic transducer, 17-amplitude rod, 18-adjusting bolt, 19-straightening roller. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The present invention will be further described below with reference to the accompanying drawings.

[0020] As Figure 1 shown, the present invention is a magnesium alloy electrode straightening device and method assisted by pulsed current and ultrasonic vibration, including a sequentially arranged cross-shaped limit wheel 1, a first roller electrode 2, an ultrasonic straightener 3, a second roller electrode 4 and a toothed driving wheel 5. The first roller electrode 2 and the second roller electrode 4 are powered by a pulse power supply 6; the ultrasonic straightener 3 is powered by a high-frequency AC power supply 7, which not only eliminates the residual stress generated during the straightening of the metal electrode, but also ensures the straightness of the electrode, and guarantees its service performance and life. The toothed driving wheel 5 provides power for the straightening of the magnesium alloy electrode.

[0021] As Figure 2 shown, the first roller electrode 2 and the second roller electrode 4 have the same structure, and both include a roller frame 10, a conductive roller group 11 and an electrode 8. The roller frame 10 is a hollow structure; the conductive roller group 11 is horizontally fixed inside the roller frame 10 through an insulating ceramic bearing 13; during the straightening process, the insulating ceramic bearing 13 bears the pressure to ensure the normal rotation of the roller, so that the roller is always in close contact with the electrode, reducing the friction during the straightening process. At the same time, the insulating ceramic bearing 13 ensures reliable insulation between the conductive roller group 11 and the roller frame 10. The electrode 8 contacts the conductive roller group 11 through a wire 12, and transmits the pulsed current from the conductive roller group 11 to the electrode. Opposite inlet guiding holes 9 and outlet guiding holes 14 with insulation treatment are provided on the roller frame 10, and the inlet guiding holes 9 and the outlet guiding holes 14 are respectively located in the straightening direction of the conductive roller group 11; on both sides of the roller frame 10 in the straightening direction of the conductive roller group 11, there are perforated insulating plates 15, which further prevent electric shock caused by operation errors.

[0022] As shown Figure 3 in Figure 1, the ultrasonic straightener 3 includes an ultrasonic transducer 16, an amplitude rod 17, and two sets of mutually perpendicular straightening roller wheels 19. The straightening roller wheels 19 are fixed in the amplitude rod 17 through bearings. There are openings on the amplitude rod 17 for fixing the adjusting bolts 18. The straightening roller wheels 19 adjust the roller gap through the adjusting bolts 18 on the amplitude rod 17. The ultrasonic transducer 16 is arranged at the rear end of the amplitude rod 17.

[0023] During the implementation of the straightening process, the magnesium alloy electrode to be straightened is first initially positioned through the cross-shaped limiter 1, and then sequentially passes through the inlet guiding holes 9 of the first roller electrode 2 and enters the conductive roller group 11 inside the roller frame 10 to complete preliminary guiding. Immediately afterwards, the magnesium alloy electrode to be straightened enters the working area of the ultrasonic straightener 3, and plastic deformation is achieved under the synergistic action of the mechanical shaping of the straightening roller wheels 19 and the high-frequency ultrasonic vibration of the ultrasonic transducer 16. The magnesium alloy electrode to be straightened after ultrasonic treatment continues to be secondarily introduced into the conductive roller group 11 through the inlet guiding holes 9 of the second roller electrode 4, and finally is led out through the outlet guiding hole 14 and fixed to the driving end of the toothed driving wheel 5, and the entire straightening operation is completed through the rotational driving force of the toothed driving wheel 5.

[0024] The following are examples of straightening different alloy electrodes using the above device.

[0025] In Example 1, a method for straightening a Mg-8Gd-3Y-0.5Zr alloy electrode using the device in the present invention includes the following steps: Step 1: Set the parameters of the pulse power supply. The pulse current magnitude is 10 A, the pulse frequency is 800 Hz, and the duty cycle is 60%; set the frequency of the high-frequency AC power supply to 20 kHz.

[0026] Step 2: Adjust the roller gap of the ultrasonic straightener; Step 3: Pass a Mg-8Gd-3Y-0.5Zr alloy electrode with a diameter of Φ3 mm of the electrode to be straightened through the limit cross-shaped wheel, roller electrode, straightener, roller electrode, and toothed driving wheel, so that it is in close contact with the toothed driving wheel; Step 4: Set the rotational speed of the toothed driving wheel to 30 r / min; Step 5: Set the frequency of the ultrasonic transducer to 20 kHz, the amplitude to 15 μm, and the contact pressure to 1 MPa; Step 6: Turn on the pulse power supply, the toothed driving wheel, and the ultrasonic transducer, and start straightening the magnesium alloy electrode.

[0027] The 3-mm magnesium alloy electrode straightened in this example can be perfectly used in a laser additive manufacturing machine, and its straightness is very high, which can enable it to be accurately positioned in laser additive manufacturing, achieving high-precision and high-efficiency production and manufacturing.

[0028] In Example 2, the method for straightening a Mg-9.5Gd-4Y-2Zn-0.3Zr alloy electrode using the device of the present invention includes the following steps: Step 1: Set the parameters of the pulse power supply. The pulse current magnitude is 20 A, the pulse frequency is 500 Hz, and the duty cycle is 10%; set the frequency of the high-frequency AC power supply to 20 kHz.

[0029] Step 2: Adjust the roller gap of the ultrasonic straightener. Step 3: Pass the Mg-9.5Gd-4Y-2Zn-0.3Zr alloy electrode with a diameter of Φ3 mm to be straightened through the limiting cross-shaped wheel, roller electrodes, straightener, roller electrodes, and toothed driving wheel, so that it is in close contact with the toothed driving wheel. Step 4: Set the rotational speed of the toothed driving wheel to 50 r / min. Step 5: Set the frequency of the ultrasonic transducer to 40 kHz, the amplitude to 10 μm, and the contact pressure to 2 MPa. Step 6: Turn on the pulse power supply, the toothed driving wheel and the ultrasonic transducer, and start straightening the magnesium alloy electrode. Step 7: After straightening, obtain a magnesium alloy electrode with a straightness meeting the requirements.

[0030] In Example 3, the method for straightening an AM60b alloy electrode using the device of the present invention includes the following steps: Step 1: Set the parameters of the pulse power supply. The pulse current magnitude is 15 A, the pulse frequency is 200 Hz, and the duty cycle is 90%; set the frequency of the high-frequency AC power supply to 20 kHz.

[0031] Step 2: Adjust the roller gap of the ultrasonic straightener. Step 3: Pass the AM60b alloy electrode with a diameter of Φ3 mm to be straightened through the limiting cross-shaped wheel, roller electrodes, straightener, roller electrodes, and toothed driving wheel, so that it is in close contact with the toothed driving wheel. Step 4: Set the rotational speed of the toothed driving wheel to 20 r / min. Step 5: Set the frequency of the ultrasonic transducer to 30 kHz, the amplitude to 30 μm, and the contact pressure to 0.5 MPa. Step 6: Turn on the pulse power supply, the toothed driving wheel and the ultrasonic transducer, and start straightening the magnesium alloy electrode. Step 7: After straightening, obtain a magnesium alloy electrode with a straightness meeting the requirements.

[0032] Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, it is not a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications or deformations that can be made without creative efforts on the basis of the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A straightening device for magnesium alloy welding rods assisted by pulsed current and ultrasonic vibration, characterized in that: It includes a limit cross wheel (1), a first roller electrode (2), an ultrasonic straightener (3), a second roller electrode (4) and a toothed driving wheel (5) arranged in sequence; the first roller electrode (2) and the second roller electrode (4) are powered by a pulse power supply (6); the ultrasonic straightener (3) is powered by a high-frequency AC power supply (7); the toothed driving wheel (5) provides power for the straightening of the magnesium alloy welding rod.

2. The straightening device for magnesium alloy welding rods assisted by pulse current and ultrasonic vibration according to claim 1, characterized in that: The roller electrode includes a roller frame (10), a conductive roller group (11) and an electrode (8); the roller frame (10) is a hollow structure; the conductive roller group (11) is horizontally fixed inside the roller frame (10) through an insulating ceramic bearing (13); the electrode (8) is in contact with the conductive roller group (11); the roller frame (10) is provided with an inlet guiding hole (9) and an outlet guiding hole (14) with insulation treatment relatively, and the inlet guiding hole (9) and the outlet guiding hole (14) are respectively located in the straightening direction of the conductive roller group (11); perforated insulating plates (15) are arranged on both sides of the outside of the roller frame (10) in the straightening direction.

3. The straightening device for magnesium alloy welding rods assisted by pulse current and ultrasonic vibration according to claim 1, wherein: The ultrasonic straightener (3) includes an ultrasonic transducer (16), an amplitude rod (17) and two groups of straightening roller wheels (19) perpendicular to each other; the straightening roller wheels (19) are fixed in the amplitude rod (17) through bearings, and the ultrasonic transducer (16) is arranged at the rear end of the amplitude rod (17).

4. A straightening device for magnesium alloy welding rods assisted by pulsed current and ultrasonic vibration according to claim 3, characterized in that: The roller gap of the straightening roller wheel (19) is adjusted through an adjusting bolt (18) on the amplitude rod (17).

5. The straightening device for magnesium alloy welding rods assisted by pulsed current and ultrasonic vibration according to claim 2, characterized in that: The electrode (8) is reliably insulated from the roller frame (10).

6. A straightening method for magnesium alloy welding rods assisted by pulsed current and ultrasonic vibration using the above device, characterized in that, It includes the following steps: Step 1, set the parameters of the pulse power supply and the high-frequency AC power supply; Step 2, adjust the roller gap of the ultrasonic straightener; Step 3, pass the magnesium alloy welding rod to be straightened through the limit cross wheel, the first roller electrode, the ultrasonic straightener, the second roller electrode and the toothed driving wheel in sequence, and make it in close contact with the toothed driving wheel; Step 4, set the rotation speed of the toothed driving wheel; Step 5, set the frequency, amplitude and contact pressure of the ultrasonic transducer; Step 6, turn on the pulse power supply, the high-frequency AC power supply, the toothed driving wheel and the ultrasonic transducer, and start to straighten the magnesium alloy welding rod; Step 7, after the straightening is completed, obtain a magnesium alloy welding rod with a straightness meeting the requirements.

7. A straightening method for a magnesium alloy welding rod assisted by pulsed current and ultrasonic vibration using the above device according to claim 6, characterized in that: Set the pulse current in Step 1 to be 10 - 20A, the pulse frequency to be 200 - 800Hz, and the duty cycle to be 10% - 90%, to ensure that the temperature of the welding rod does not exceed 200°C during the straightening process; the frequency of the high-frequency AC current power supply is 20kHz.

8. A method for straightening a magnesium alloy welding rod assisted by pulse current and ultrasonic vibration using the above device according to claim 6, characterized in that: The rotation speed of the driving wheel in Step 4 is 20 - 50r / min.

9. A method for straightening a magnesium alloy welding rod assisted by pulsed current and ultrasonic vibration using the above device according to claim 6, characterized in that: In Step 5, the frequency of the ultrasonic transducer is 20 - 40kHz, the amplitude is 10 - 30μm, and the contact pressure is 0.1 - 2MPa.

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