A method for preparing a rare earth magnesium alloy wire for electric arc additive manufacturing

Abstract

The application discloses a preparation method of rare earth magnesium alloy wire suitable for electric arc additive manufacturing and belongs to the technical field of metal wire processing. The method specifically comprises the following steps: (1) taking a magnesium alloy bar with a diameter of Φ3-6 mm as raw material, and preparing a wire with a diameter of Φ1.35-1.45 mm through a hot drawing process; (2) connecting the wire obtained in the step (1) by using a resistance butt welding process; and (3) performing skinning treatment on the wire obtained in the step (2), so as to finally obtain a magnesium alloy wire with good surface finish and diameter. Through the hot drawing, resistance butt welding and skinning processes, the obtained wire is not limited in length, uniform in diameter, bright in surface, free of peeling and cracks; meanwhile, the resistance butt welding joint part is dense, free of pores and oxidation inclusions, the strength of the joint part is close to that of the base material, and the diameter and roundness of the joint part after the skinning treatment are the same as those of the wire; and the prepared wire is good in cooperation with a wire feeding system in a subsequent electric arc additive process and free of wire breaking.

Description

Technical Field

[0001] This invention belongs to the field of metal wire processing technology, specifically relating to a method for preparing rare earth magnesium alloy wire for arc additive manufacturing. Background Technology

[0002] Rare earth magnesium alloys possess low density, high specific strength and stiffness, and excellent high-temperature performance, making them promising for applications in aerospace, transportation, and weaponry. Particularly in replacing traditional steel materials and significantly reducing the weight of structures such as missiles and satellites, magnesium alloys offer unparalleled advantages. However, due to magnesium's close-packed hexagonal structure, its relatively low glide coefficient at room temperature results in poor plastic deformation, posing significant challenges to traditional processing methods. Arc additive manufacturing technology, using an electric arc as a heat source and metal wire as raw material, enables the efficient fabrication of large-size and complex shapes through precise parameter control and layer-by-layer deposition, thus providing new technological support for the development and fabrication of rare earth magnesium alloy products.

[0003] The wire diameter used in arc additive manufacturing is usually Φ1.2mm. For rare earth magnesium alloys, the poor room temperature plasticity and high high temperature deformation resistance make wire preparation very difficult. Specifically, this is reflected in: (1) frequent drawing and annealing make the process cumbersome and the production efficiency low; (2) breakage is easy to occur during the drawing process, requiring shutdown and restart, reducing production efficiency, and the length of the prepared wire is limited; (3) although the length of the thick wire can be increased by welding, there are still differences in microstructure and properties between the weld and the base material, and wire breakage will still occur during subsequent frequent drawing and annealing. Therefore, efficient rare earth magnesium alloy wire preparation methods and high-quality rare earth magnesium alloy wire raw materials have become one of the current research hotspots. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing rare earth magnesium alloy wire for arc additive manufacturing, which involves hot drawing, resistance welding, and peeling processes to prepare wire with a diameter of [missing information]. This study aims to develop magnesium alloy wires with good surface finish and stable and reliable performance for arc additive manufacturing.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing rare earth magnesium alloy wire for arc additive manufacturing, using magnesium alloy rods with a diameter of Φ3-6mm as raw material, and preparing wires with a diameter of Φ3-6mm through hot drawing, resistance welding and peeling processes. The preparation method of the magnesium alloy wire includes the following steps:

[0007] Step 1: Hot drawing. Magnesium alloy rods are drawn by a drawing drum and pass through a lubricant, a tubular heating furnace, and a drawing die in sequence to achieve the purpose of diameter reduction. After several hot drawing passes, wires with a diameter of Φ1.35~1.45mm are produced.

[0008] Step 2, resistance welding: Grind the end face of the wire obtained in Step 1 to make it flat. At the same time, grind and clean the lubricating layer and oxide layer on the surface of the wire within 10mm on one side of the end face. Align the end faces of the two wires and fix them in the clamp of the resistance welding machine. Power on under argon protection. The end faces of the wires go through the process of preheating, welding and slow cooling to achieve connection. Finally, grind the weld joint flat.

[0009] Step 3, peeling: The filaments obtained in Step 2 are pulled by the peeling machine drum through a peeling die or a combination of a peeling die and a calendering die to remove the lubricating and oxide layers from the filament surface and control the diameter accuracy of the finished filaments. The final peeling pass uses a combination of a peeling die and a calendering die to obtain filaments with a smooth surface and a diameter of [missing information]. Magnesium alloy wire.

[0010] Furthermore, the composition of the magnesium alloy rod comprises by mass percentage: 8-13% Gd, 0-5% Y, 0-3% Zn, 0-0.3% Zr, with the remainder being Mg.

[0011] Furthermore, in step one, a spool with a diameter of 800mm is used for hot drawing of magnesium alloy bars with a diameter of Φ3 to 6mm, and a spool with a diameter of Φ400mm is used for hot drawing of magnesium alloy wires with a diameter of less than 3mm.

[0012] Furthermore, in step one, the lubricant used for hot drawing is graphite emulsion, the hot drawing temperature is 400-500℃, the single-die deformation of hot drawing is 10%-20%, and the hot drawing rate is 1-3m / min.

[0013] Furthermore, in step two, the distance between the resistance welding fixtures is 1-3 mm, and the end faces are strictly aligned. The preheating current is 50-80 A, the time is 0.05-0.1 s, and the upsetting pressure is 0.02-0.06 MPa. The welding current is 100-200 A, the time is 0.3-0.6 s, and the upsetting pressure is 0.1-0.3 MPa. The slow cooling current is 10-40 A, the time is 0.1-0.2 s, and the upsetting pressure is 0 MPa.

[0014] Furthermore, in step three, the diameter of the roll used for peeling is Φ400mm; specifically, the first and second peeling passes use only peeling dies, with a single die reduction of 0.1-0.2mm and a peeling rate of 10-20m / min, yielding magnesium alloy wire with a diameter of Φ1.25mm; the final peeling pass uses a combination of peeling and calendering dies, with the peeling die reducing 0.03mm and the calendering die reducing 0.02mm respectively, and a peeling rate of 10m / min, yielding a magnesium alloy wire with a diameter of... Magnesium alloy wire.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. This invention employs a single-die hot drawing process. The rod / wire is heated to a high temperature before deformation through the die, which not only eliminates deformation energy storage and defects caused by the previous deformation to a certain extent, but also greatly reduces deformation energy storage and defects caused by the current deformation, avoiding the accumulation of deformation energy storage and defects. Therefore, the wire preparation technology disclosed in this invention fully utilizes the basic principles of hot deformation. Under good lubrication conditions, it rationally matches the relationship between deformation temperature, single-die deformation amount, and drawing rate, achieving the preparation process of rare earth magnesium alloy wire diameters from Φ6mm to Φ1.35~1.45mm without the need for an intermediate annealing process, shortening the preparation process and improving preparation efficiency.

[0017] 2. This invention employs resistance butt welding for wire connection. The wire end face undergoes preheating, welding, and slow cooling, greatly mitigating stress concentration and the difference in microstructure between the weld and the base material caused by direct welding. Under upsetting pressure, the weld exhibits a dense microstructure free of porosity and oxide inclusions. Furthermore, without intermediate annealing, the weld strength can approach that of the base material, ensuring that the weld does not break during subsequent peeling processes and wire feeding in arc additive manufacturing. Therefore, the resistance butt welding technology disclosed in this invention combines traditional resistance butt welding with heat treatment technology through automated control, achieving efficient, high-performance, and stable wire connection.

[0018] 3. This invention employs a peeling process to remove the lubricating and oxide layers from the surface of the filament. In the final peeling stage, a combined mold consisting of a peeling die and a calendering die is used to further remove the microgrooves formed on the filament surface by the previous peeling process, improving the surface smoothness of the filament. Simultaneously, the accuracy of the finished filament diameter is controlled to achieve the desired finish. In summary, the peeling process disclosed in this invention simultaneously achieves the effects of reducing wire diameter, improving surface smoothness, and improving diameter accuracy.

[0019] 4. This invention employs a process of hot drawing, resistance welding, and peeling to produce rare earth magnesium alloy wire for arc additive manufacturing. The hot-drawn wire, after resistance welding, can be prepared into wires of any length. After simple grinding to smooth the weld joint, the diameter reduction of the peeling die is controlled to ensure no breakage at the weld joint, thus achieving the preparation of rare earth magnesium alloy wire with uniform and stable diameter, unlimited length, and good surface finish. Attached Figure Description

[0020] Figure 1 This is a photograph of the second phase morphology in a rare earth magnesium alloy wire with a diameter of Φ1.4mm prepared by hot drawing in Example 1 of the present invention.

[0021] Figure 2 This is a photograph of the grain morphology of a rare earth magnesium alloy wire with a diameter of Φ1.4mm prepared by hot drawing in Example 1 of the present invention.

[0022] Figure 3 The figure shows the room temperature tensile stress-strain curve of a rare earth magnesium alloy wire with a diameter of Φ1.4mm prepared by hot drawing in Example 1 of the present invention.

[0023] Figure 4 This is a photograph of the microstructure of the weld after resistance welding of rare earth magnesium alloy wire with a diameter of Φ1.4mm in Example 1 of the present invention.

[0024] Figure 5 This is the room temperature tensile stress-strain curve of the rare earth magnesium alloy wire with a diameter of Φ1.4mm after resistance welding in Example 1 of the present invention.

[0025] Figure 6 The diameter after peeling in Embodiment 1 of the present invention is Macroscopic photograph of rare earth magnesium alloy wire.

[0026] Figure 7 The diameter after peeling in Embodiment 1 of the present invention is Microscopic morphology of rare earth magnesium alloy wire. Detailed Implementation

[0027] This invention provides a method for preparing rare-earth magnesium alloy wire for arc additive manufacturing. The method uses magnesium alloy rods with a diameter of Φ3-6mm as raw material (the preparation of magnesium alloy rods with a diameter of Φ3-6mm is existing technology, for example, it can be prepared by the staged deformation hot extrusion technology described in CN2024100464283, which will not be elaborated here). The specific composition includes, by mass percentage: 8-13% Gd, 0-5% Y, 0-3% Zn, 0-0.3% Zr, with the remainder being Mg. The magnesium alloy rods are prepared by hot drawing, resistance welding, and peeling processes to obtain a diameter of... The magnesium alloy wire material specifically includes the following steps:

[0028] Step one, hot drawing: Magnesium alloy rods are drawn sequentially through a lubricant, a tubular furnace, and a drawing die by a drawing drum to achieve diameter reduction. After several passes of hot drawing, wires with a diameter of Φ1.35–1.45 mm are produced. In one specific implementation, a drum with a diameter of Φ800 mm is used for hot drawing magnesium alloy rods with a diameter of Φ3–6 mm. For magnesium alloy wires with a diameter less than 3 mm, a drum with a diameter of Φ400 mm is used. As the diameter decreases, residual stress from deformation and cooling can easily lead to increased bending of the wires, even causing them to entangle, making the unwinding process impossible. Therefore, a smaller drum is used to accommodate the degree of bending and improve the uniformity of the entire roll of wire. Furthermore, the lubricant used in this invention is graphite emulsion, the hot drawing temperature is 400–500℃, the single-die deformation is 10%–20%, and the hot drawing rate is 1–3 m / min. In conventional drawing followed by intermediate annealing, intermediate annealing is used to eliminate deformation energy storage and defects caused by deformation. However, if intermediate annealing is incomplete, the plastic deformation capacity of the wire cannot be restored, and continued deformation can easily lead to fracture. Excessive intermediate annealing can cause abnormal growth of grains and the second phase in the alloy, resulting in uneven microstructure and reduced plastic deformation capacity. This step fully utilizes the basic principles of hot deformation, and under good lubrication conditions, rationally matches the relationship between deformation temperature, single-die deformation amount, and drawing rate, so that the wire can always maintain good and stable plastic deformation capacity. This allows for the preparation of rare earth magnesium alloy wire with diameters from Φ6mm to Φ1.35~1.45mm without the need for an intermediate annealing process.

[0029] Step two, resistance butt welding: Grind the end face of the wire obtained in step one until it is smooth. Simultaneously, clean the lubricating and oxide layers from the wire surface within a 10mm radius on one side of the end face. Align the two wire end faces and fix them in the fixture of the resistance butt welding machine. Under argon protection, power is applied, and the wire end faces undergo preheating, welding, and slow cooling to achieve connection. Finally, grind the weld joint smooth. In this step, the distance between the resistance butt welding fixtures is 1–3mm, ensuring strict alignment of the end faces. The preheating current is 50–80A, time 0.05–0.1s, and upsetting pressure is 0.02–0.06MPa; the welding current is 100–200A, time 0.3–0.6s, and upsetting pressure is 0.1–0.3MPa; the slow cooling current is 10–40A, time 0.1–0.2s, and upsetting pressure is 0MPa. This invention employs resistance welding for wire connection. The wire end face undergoes preheating, welding, and slow cooling, significantly mitigating stress concentration and microstructural differences between the weld and base metal caused by direct welding. Under upsetting pressure, the weld exhibits a dense, non-porous, and oxide-free microstructure. Furthermore, without intermediate annealing, the weld strength approaches that of the base metal, ensuring no breakage occurs during subsequent peeling processes and wire feeding in arc additive manufacturing. The inventors believe that the parameters used for preheating, welding, and cooling are effective. For the preheating, welding, and slow cooling processes, parameters exceeding the specified range lead to excessively high wire end face temperatures and insufficient cooling, resulting in severe surface oxidation, inclusions, poor end face bonding, and coarse grains and second phases at the weld. Parameters below the specified range lead to excessively low wire end face temperatures, resulting in incomplete weld penetration and excessive residual stress at the weld. Therefore, the parameters for preheating, welding, and slow cooling are effective.

[0030] Step 3, peeling: The filaments obtained in Step 2 are pulled by the peeling machine drum through a peeling die or a combination of a peeling die and a calendering die to remove the lubricating and oxide layers from the filament surface and control the diameter accuracy of the finished filaments. The final peeling pass uses a combination of a peeling die and a calendering die to obtain filaments with a smooth surface and a diameter of [missing information]. Magnesium alloy wire. In this step, the diameter of the spool used for peeling is Φ400mm; the first and second peeling passes use only peeling dies, with a single die reduction of 0.1-0.2mm and a peeling rate of 10-20m / min, yielding magnesium alloy wire with a diameter of Φ1.25mm; the final peeling pass uses a combination of peeling and calendering dies, with the peeling die reducing 0.03mm and the calendering die reducing 0.02mm, and the peeling rate of 10m / min, yielding magnesium alloy wire with a diameter of Magnesium alloy wire. This peeling process simultaneously achieves the effects of wire diameter reduction, improved surface finish, and improved diameter accuracy.

[0031] This invention will further describe in detail, with reference to the accompanying drawings and specific embodiments, a method for preparing rare-earth magnesium alloy wire for arc additive manufacturing. It should be noted that these specific embodiments are merely illustrative and do not constitute any limitation on the invention.

[0032] Example 1

[0033] This embodiment provides a method for preparing Mg-9Gd-4Y-1Zn-0.3Zr (wt%) alloy wire for arc additive manufacturing. The diameter of the magnesium alloy rod raw material is Φ5mm. The specific steps include:

[0034] Step 1: Hot drawing. Rare earth magnesium alloy rods / wires are drawn sequentially through a lubricant, a tubular furnace, and a drawing die by a drawing drum to achieve diameter reduction. During the hot drawing process, magnesium alloy rods / wires with diameters of Φ5~3mm are drawn using a drum with a diameter of Φ800mm, while those with diameters less than Φ3mm are drawn using a drum with a diameter of Φ400mm. The lubricant used in the hot drawing is graphite emulsion. The hot drawing temperature is 450℃, the single-die deformation is 15%, and the hot drawing rate is 2.5m / min. After 16 passes of hot drawing, a wire with a diameter of Φ1.4mm is produced.

[0035] Step 2, resistance welding: Grind the end face of the wire obtained in step (1) until it is flat. At the same time, clean the lubricating layer and oxide layer on the surface of the wire within 10mm on one side of the end face. Align the end faces of the two wires and fix them in the fixture of the resistance welding machine. The fixture spacing is 2mm. Ensure that the end faces are strictly aligned. Power is applied under argon protection. The end faces of the wires undergo preheating, welding and slow cooling to achieve connection. The preheating current is 50A, the time is 0.1s and the upsetting pressure is 0.05MPa. The welding current is 180A, the time is 0.4s and the upsetting pressure is 0.2MPa. The slow cooling current is 10A, the time is 0.2s and the upsetting pressure is 0MPa. Finally, grind the weld joint until it is flat.

[0036] Step 3, peeling: The wire obtained in step (2) is pulled by the peeling machine drum through a single peeling die and a combined die including a peeling die and a calendering die. The drum diameter is Φ400mm, the diameter reduction of the single peeling die is 0.15mm, and the peeling rate is 20m / min, resulting in a magnesium alloy wire with a diameter of Φ1.25mm. In the combined die of peeling and calendering, the diameter reduction of the peeling die is 0.03mm, the diameter reduction of the calendering die is 0.02mm, and the peeling rate is 10m / min, resulting in a magnesium alloy wire with a diameter of Φ1.25mm. Magnesium alloy wire.

[0037] The microstructure and room temperature tensile stress-strain curve of the Φ1.4mm Mg-9Gd-4Y-1Zn-0.3Zr alloy wire prepared by hot drawing in this embodiment are shown below. Figure 1 , 2 As shown in Figure 3, microstructural characterization reveals a large number of strip-shaped and granular second phases within the wire, with most granules smaller than 5 μm and an average grain size of approximately 8 μm. Therefore, after hot drawing deformation, both the second phase and grain size in the alloy are significantly refined. Room temperature tensile testing shows that the wire's yield strength reaches 280 MPa, tensile strength reaches 330 MPa, and elongation reaches 9%. The microstructure and room temperature tensile stress-strain curves at the weld after resistance butt welding are shown in Figures 3 and 4. Figure 4 and 5 As shown, a discontinuous network of second phases is formed at the grain boundaries in the weld, with a grain size of approximately 1 μm. A heat-affected zone (HAZ) exists between the weld and the base metal, serving as a transitional region for microstructural changes. During room temperature tensile testing, the specimen fractured in the HAZ, achieving a yield strength of 283 MPa, a tensile strength of 315 MPa, and an elongation of 4%. This indicates that after resistance welding, the weld strength is close to that of the base metal, while the plasticity is significantly reduced. However, the high strength and low plasticity combination still ensures smooth wire feeding during arc additive manufacturing. The diameter after peeling is... Macroscopic photographs and surface microstructures of the filament material, such as Figure 6 and 7 As shown, the surface of the filament is bright, without peeling or cracks, and the diameter is concentrated between Φ1.19 and 1.20 mm, which meets the dimensional accuracy requirements. At the same time, no micro-grooves caused by the peeling mold were observed in the micro-morphology of the surface, and a large number of fine second-phase particles were observed distributed on the surface, which further indicates that the surface of the filament has good smoothness.

[0038] Example 2

[0039] This embodiment provides a method for preparing Mg-8Gd-3Y-2Zn-0.3Zr (wt%) alloy wire for arc additive manufacturing. The diameter of the magnesium alloy rod raw material is Φ6mm. The specific steps include:

[0040] Step 1: Hot drawing. Rare earth magnesium alloy rods / wires are drawn sequentially through a lubricant, a tubular furnace, and a drawing die by a drawing drum to achieve diameter reduction. During the hot drawing process, magnesium alloy rods / wires with diameters of Φ6~3mm are drawn using a drum with a diameter of Φ800mm, while those with diameters less than Φ3mm are drawn using a drum with a diameter of Φ400mm. The lubricant used in the hot drawing is graphite emulsion, the hot drawing temperature is 500℃, the single-die deformation is 20%, and the hot drawing rate is 1m / min. After 14 passes of hot drawing, a wire with a diameter of Φ1.35mm is produced.

[0041] Step 2, resistance welding: Grind the end face of the wire obtained in step (1) until it is flat. At the same time, clean the lubricating layer and oxide layer on the surface of the wire within 10mm on one side of the end face. Align the end faces of the two wires and fix them in the fixture of the resistance welding machine. The fixture spacing is 1mm. Ensure that the end faces are strictly aligned. Power is applied under argon protection. The end faces of the wires undergo preheating, welding and slow cooling to achieve connection. The preheating current is 80A, the time is 0.05s and the upsetting pressure is 0.02MPa. The welding current is 200A, the time is 0.3s and the upsetting pressure is 0.1MPa. The slow cooling current is 40A, the time is 0.1s and the upsetting pressure is 0MPa. Finally, grind the weld joint until it is flat.

[0042] Step 3, peeling: The wire obtained in step (2) is pulled by the peeling machine drum through a single peeling die and a combined die including a peeling die and a calendering die. The drum diameter is Φ400mm, the diameter reduction of the single peeling die is 0.1mm, and the peeling rate is 15m / min, resulting in a magnesium alloy wire with a diameter of Φ1.25mm. In the combined die of peeling and calendering, the diameter reduction of the peeling die is 0.03mm, the diameter reduction of the calendering die is 0.02mm, and the peeling rate is 10m / min, resulting in a magnesium alloy wire with a diameter of Φ1.25mm. Magnesium alloy wire.

[0043] In this embodiment, a 1.35mm diameter Mg-8Gd-3Y-2Zn-0.3Zr alloy wire was prepared by hot drawing. Room temperature tensile tests showed that the wire's yield strength reached 260MPa, tensile strength reached 350MPa, and elongation reached 5%. After resistance welding, the sample fractured in the heat-affected zone during room temperature tensile testing, yielding a yield strength of 266MPa, tensile strength of 340MPa, and elongation of 3.7%.

[0044] Example 3

[0045] This embodiment provides a method for preparing Mg-8Gd-3Y-0.3Zr (wt%) alloy wire for arc additive manufacturing. The diameter of the magnesium alloy rod raw material is Φ3mm. The specific steps include:

[0046] Step 1: Hot drawing. Rare earth magnesium alloy rods / wires are drawn sequentially through a lubricant, a tubular furnace, and a drawing die by a drawing drum to achieve diameter reduction. During the hot drawing process, magnesium alloy rods / wires with a diameter less than Φ3mm are drawn using a Φ400mm drum. The lubricant used is graphite emulsion. The hot drawing temperature is 400℃, the single-die deformation is 10%, and the hot drawing rate is 3m / min. After 14 passes of hot drawing, a wire with a diameter of Φ1.45mm is produced.

[0047] Step 2, resistance welding: Grind the end face of the wire obtained in step (1) until it is flat. At the same time, clean the lubricating layer and oxide layer on the surface of the wire within 10mm on one side of the end face. Align the end faces of the two wires and fix them in the fixture of the resistance welding machine. The fixture spacing is 3mm. Ensure that the end faces are strictly aligned. Power is applied under argon protection. The end faces of the wires undergo preheating, welding and slow cooling to achieve connection. The preheating current is 60A, the time is 0.08s and the upsetting pressure is 0.06MPa. The welding current is 100A, the time is 0.6s and the upsetting pressure is 0.3MPa. The slow cooling current is 20A, the time is 0.15s and the upsetting pressure is 0MPa. Finally, grind the weld joint until it is flat.

[0048] Step 3, peeling: The wire obtained in step (2) is pulled by the peeling machine drum through a single peeling die and a combined die including a peeling die and a calendering die. The drum diameter is Φ400mm, the diameter reduction of the single peeling die is 0.2mm, and the peeling rate is 10m / min, resulting in a magnesium alloy wire with a diameter of Φ1.25mm. In the combined die of peeling and calendering, the diameter reduction of the peeling die is 0.03mm, the diameter reduction of the calendering die is 0.02mm, and the peeling rate is 10m / min, resulting in a magnesium alloy wire with a diameter of Φ1.25mm. Magnesium alloy wire.

[0049] In this embodiment, a 1.45mm diameter Mg-8Gd-3Y-0.3Zr alloy wire was prepared by hot drawing. Room temperature tensile tests showed that the wire's yield strength reached 370MPa, tensile strength reached 420MPa, and elongation reached 4.7%. After resistance butt welding, the sample fractured in the heat-affected zone during room temperature tensile testing, yielding a yield strength of 383MPa, tensile strength of 400MPa, and elongation of 3.5%.

[0050] Example 4

[0051] This embodiment provides a method for preparing Mg-13Gd-1Zn (wt%) alloy wire for arc additive manufacturing. The diameter of the magnesium alloy rod raw material is Φ5mm. The specific steps include:

[0052] Step 1: Hot drawing. Rare earth magnesium alloy rods / wires are drawn sequentially through a lubricant, a tubular furnace, and a drawing die by a drawing drum to achieve diameter reduction. During the hot drawing process, magnesium alloy rods / wires with diameters of Φ5~3mm are drawn using a drum with a diameter of Φ800mm, while those with diameters less than Φ3mm are drawn using a drum with a diameter of Φ400mm. The lubricant used in the hot drawing is graphite emulsion. The hot drawing temperature is 450℃, the single-die deformation is 15%, and the hot drawing rate is 2m / min. After 16 passes of hot drawing, a wire with a diameter of Φ1.45mm is produced.

[0053] Step 2, resistance welding: Grind the end face of the wire obtained in step (1) until it is flat. At the same time, clean the lubricating layer and oxide layer on the surface of the wire within 10mm on one side of the end face. Align the end faces of the two wires and fix them in the fixture of the resistance welding machine. The fixture spacing is 2mm. Ensure that the end faces are strictly aligned. Power is applied under argon protection. The end faces of the wires undergo preheating, welding and slow cooling to achieve connection. The preheating current is 80A, the time is 0.08s and the upsetting pressure is 0.05MPa. The welding current is 150A, the time is 0.4s and the upsetting pressure is 0.2MPa. The slow cooling current is 20A, the time is 0.2s and the upsetting pressure is 0MPa. Finally, grind the weld joint until it is flat.

[0054] Step 3, peeling: The wire obtained in step (2) is drawn by the peeling machine drum through two peeling dies and one combined die including a peeling die and a calendering die. The drum diameter is Φ400mm, the diameter reduction of the first and second peeling dies is 0.1mm, and the peeling rate is 20m / min, resulting in magnesium alloy wire with a diameter of Φ1.25mm. In the combined die of peeling and calendering, the diameter reduction of the peeling die is 0.03mm, the diameter reduction of the calendering die is 0.02mm, and the peeling rate is 10m / min, resulting in magnesium alloy wire with a diameter of Φ1.25mm. Magnesium alloy wire.

[0055] In this embodiment, a Mg-13Gd-1Zn alloy wire with a diameter of Φ1.45mm was prepared by hot drawing. Room temperature tensile tests showed that the wire's yield strength reached 496MPa, tensile strength reached 553MPa, and elongation reached 4%. After resistance welding, the sample fractured in the heat-affected zone during room temperature tensile testing, yielding a yield strength of 455MPa, tensile strength of 480MPa, and elongation of 4.2%.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for improving the preparation efficiency of rare earth magnesium alloy wire for arc additive manufacturing without requiring an intermediate annealing process, characterized in that, This method uses magnesium alloy rods with a diameter of Φ3~6mm as raw material, and prepares rods with a diameter of Φ6mm through hot drawing, resistance welding and peeling processes. The magnesium alloy wire material specifically includes the following steps: Step 1: Hot drawing. Magnesium alloy rods are drawn by a drawing drum and pass through a lubricant, a tubular heating furnace, and a drawing die in sequence to achieve the purpose of diameter reduction. No intermediate annealing process is required. After several hot drawing passes, wires with a diameter of Φ1.35~1.45mm are produced. Step 2, resistance welding: Grind the end face of the wire obtained in Step 1 to make it flat. At the same time, grind and clean the lubricating layer and oxide layer on the surface of the wire within 10mm on one side of the end face. Align the end faces of the two wires and fix them in the fixture of the resistance welding machine. Power on under argon protection. The end faces of the wires go through the process of preheating, welding and slow cooling to achieve connection. Finally, grind the weld joint flat. No post-weld annealing is required. Step 3, peeling: The filaments obtained in Step 2 are pulled by the peeling machine drum through a peeling die or a combination of a peeling die and a calendering die to remove the lubricating and oxide layers from the filament surface and control the diameter accuracy of the finished filaments. The final peeling pass uses a combination of a peeling die and a calendering die to obtain filaments with a smooth surface and a diameter of [missing information]. Magnesium alloy wire; In step one, the lubricant used for hot drawing is graphite emulsion, the hot drawing temperature is 400~500℃, the deformation of a single hot drawing die is 10%~20%, and the hot drawing speed is 1~3m / min. In step two, the spacing between the resistance welding fixtures is 1-3mm, and the end faces are strictly aligned. The preheating current is 50-80A, the time is 0.05-0.1s, and the upsetting pressure is 0.02-0.06MPa. The welding current is 100-200A, the time is 0.3-0.6s, and the upsetting pressure is 0.1-0.3MPa. The slow cooling current is 10-40A, the time is 0.1-0.2s, and the upsetting pressure is 0MPa. In step three, the diameter of the roll used for peeling is Φ400mm. The first and second peeling passes use only a peeling die, with a single die reduction of 0.1-0.2mm and a peeling rate of 10-20m / min, yielding magnesium alloy wire with a diameter of Φ1.25mm. The final peeling pass uses a combination of a peeling die and a calendering die; correspondingly, the peeling die reduces the diameter by 0.03mm, the calendering die reduces the diameter by 0.02mm, and the peeling rate is 10m / min, yielding a magnesium alloy wire with a diameter of... Magnesium alloy wire.

2. The method according to claim 1, characterized in that, The magnesium alloy rod comprises, by mass percentage: 8-13% Gd, 0-5% Y, 0-3% Zn, 0-0.3% Zr, with the remainder being Mg.

3. The method according to claim 1, characterized in that, In step one, a spool with a diameter of 800mm is used for hot drawing of magnesium alloy bars with a diameter of Φ3~6mm, and a spool with a diameter of Φ400mm is used for hot drawing of magnesium alloy wires with a diameter of less than 3mm.

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