Short-process magnesium alloy wire continuous extrusion preparation method and system

Abstract

The short-process magnesium alloy wire continuous extrusion preparation method comprises the following steps that a, magnesium alloy extrusion materials are prepared, the thickness of the extrusion materials is 0.03-0.1 mm, and the length of the extrusion materials is 0.3-5 mm; b) preheating an extrusion wheel, wherein the preheating temperature is 250-500 DEG C; c) continuous extrusion: continuously introducing inert gas into an extrusion cavity, then feeding the magnesium alloy scraps into the extrusion cavity, and driving the magnesium alloy scraps to pass through an extrusion die along with rotation of an extrusion wheel to extrude a wire; and d) shaping and sizing: carrying out shaping and sizing treatment on the obtained wire material to obtain the magnesium alloy wire material with the final required diameter. According to the method, the problem of lengthy magnesium wire processing flow is solved, the problem of single type of magnesium alloy wires is solved, and the problem of efficient batch production of magnesium welding wires and wires for additive manufacturing of different component systems is solved, so that industrial production of the magnesium alloy wires is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal plastic forming, and in particular relates to a short-process magnesium alloy wire continuous extrusion preparation method and system. Background Art

[0002] As one of the key raw materials for magnesium alloy products, magnesium wire is not only the main connecting auxiliary material for magnesium alloy structural parts, but also widely used as welding wire for deformed products such as magnesium alloy tubes, rods, profiles and plates, and also used as welding wire for repair welding of magnesium alloy castings; magnesium wire can also be used as raw material for arc additive manufacturing, replacing the current high-risk magnesium powder in the field of additive manufacturing, and plays an important role in the future development trend of magnesium alloy component forming technology. However, due to the close-packed hexagonal crystal structure of magnesium, its room temperature processing ability is poor, which brings certain difficulties to the large-scale plastic forming of high-quality magnesium welding wire and additive manufacturing wire with a wire diameter of less than 2mm.

[0003] The conventional magnesium wire preparation process includes semi-continuous casting, homogenization heat treatment, hot extrusion bar preparation, drawing, intermediate annealing, scraping and layer winding, etc.; and the drawing process usually requires a small deformation amount and a large number of drawing passes, and frequent intermediate annealing is performed to eliminate work hardening and avoid cracks or even wire breakage in the wire. Therefore, there are disadvantages such as complex and lengthy processing flow, high production energy consumption, low production efficiency, and limited wire length. More importantly, this technology is limited to the industrial production of Mg-Al alloy wires that are easier to plastically deform. However, with the development and application of new high-strength and high-flame-retardant magnesium alloy materials in recent years, the demand for hot cracking and plastic deformation of magnesium alloys containing strengthening elements such as Ca, RE, and Zn has further increased. The hot extrusion and drawing process window is narrow, and higher requirements are placed on the extrusion force and temperature control during the processing process, resulting in a significant decrease in the wire yield and production efficiency, making it difficult to produce in batches and stably.

[0004] Continuous extrusion is a process that uses the heat generated by the extrusion friction between the metal raw material and the rotating extrusion wheel to heat the metal and continuously extrude it in the mold. It has the advantages of simple process and unlimited production length. It is currently used in the continuous production of copper and aluminum wires and has the potential to develop into a new technology for the preparation of magnesium wires.

[0005] The "Method for Preparing Magnesium Alloy Welding Wire" disclosed in Chinese patent publication number CN109570826A is a method for preparing magnesium welding wire that introduces a continuous extrusion process to reduce the number of drawing passes, thereby improving production efficiency and solving the problem of magnesium welding wire joint connection. However, this technology still requires multiple processes such as conventional ingot extrusion, drawing, and intermediate annealing. The processing flow is lengthy, the process stability control of the batch production process is difficult, and the effect of improving production efficiency is limited.

[0006] The "Magnesium Alloy Wire Continuous Extrusion Forming Device and Method for Arc Additive Manufacturing" disclosed in Chinese Patent Publication No. CN114515777A is a method that combines electroplasticity and continuous extrusion, and uses pulse current to improve the continuous extrusion plastic forming performance of magnesium alloy wire. However, this method also relies on hot extrusion as a previous process to prepare the rod material for continuous extrusion, and the method has a small deformation amount in a single continuous extrusion process (extrusion ratio is less than 20), and it is necessary to go through 2-3 continuous extrusion processes to gradually reduce the diameter of the extruded rod material until the final magnesium wire product is obtained. The extrusion wheel with the corresponding wheel groove size and the extrusion die with different apertures need to be replaced between each pass. The operation is cumbersome and not conducive to actual mass production.

[0007] In summary, although there are prior arts that use continuous extrusion in the preparation method of magnesium alloy wires, they have not been able to truly solve the technical bottlenecks of the existing magnesium wire processing, such as the lengthy processing flow and complex processing procedures, which is not conducive to promotion and application. Summary of the invention

[0008] The purpose of the present invention is to provide a short-process magnesium alloy wire continuous extrusion preparation method and system, to solve the problem of lengthy magnesium wire processing process, to overcome the problem of single type of magnesium alloy wire, to solve the problem of efficient batch production of magnesium welding wire and additive manufacturing wire with different composition systems, thereby realizing the industrial production of magnesium alloy wire.

[0009] In order to achieve the above object, the present invention adopts the following technical scheme:

[0010] A short-process magnesium alloy wire continuous extrusion preparation method comprises the following steps:

[0011] a) Preparation of magnesium alloy extrusion materials

[0012] The thickness of magnesium alloy extrusion material is 0.03-0.1mm and the length is 0.3-5mm;

[0013] b) Preheating of extrusion wheel

[0014] Preheating the extrusion wheel of the extrusion device at a temperature of 250-500°C so that the surface of the extrusion wheel is evenly heated; preferably, the preheating is performed by induction heating;

[0015] c) Continuous extrusion

[0016] The inert gas is continuously introduced into the extrusion chamber, and then the magnesium alloy extrusion material is fed into the extrusion chamber. As the extrusion wheel rotates, the magnesium alloy chips are driven through the extrusion die to extrude the wire. Preferably, the inert gas is pre-introduced into the extrusion chamber for 1 to 3 minutes to ensure that the extrusion chamber is filled with inert gas before continuous extrusion is started. Preferably, the inert gas flow rate is 5 to 10 m / s. 3 / h;

[0017] d) Shaping and sizing

[0018] The wire obtained in step c) is subjected to shaping and sizing treatment to obtain a magnesium alloy wire with a final required diameter.

[0019] Preferably, in step a), the ratio of the length to the thickness of the magnesium alloy extrusion material is not less than 5:1.

[0020] Preferably, in step a), the magnesium alloy extrusion material is prepared by: first cutting the magnesium alloy ingot to cut out magnesium alloy chips with a thickness of 0.03 to 0.5 mm; then introducing the magnesium alloy chips into a ball mill, and obtaining magnesium alloy chips as extrusion materials after ball milling, with a thickness of 0.03 to 0.1 mm and a length of 0.3 to 5 mm; preferably, ball milling is performed in an inert atmosphere; preferably, the cutting process is protected by an inert atmosphere throughout the process; more preferably, the inert atmosphere is nitrogen or argon.

[0021] Preferably, in step a), the ball milling speed is 250-450 rpm, and the ball milling time is 2-6 h.

[0022] Preferably, in step a), the magnesium alloy ingot is cut by using a single rolling cutter head with a hydraulic push rod, and the feed speed is set to 90-360s / 100mm.

[0023] Preferably, in step c), the temperature of the extrusion wheel is maintained at 350-500° C. during the continuous extrusion process, and preferably, the rotation speed of the extrusion wheel is 2-10 rpm.

[0024] Preferably, in step c), the finished wire has a diameter of 2.0 mm, and the sizing die hole diameter of the extrusion die is 2.05-2.2 mm; the finished wire has a diameter of 1.6 mm, and the sizing die hole diameter of the extrusion die is 1.65-1.8 mm; the finished wire has a diameter of 1.2 mm, and the sizing die hole diameter of the extrusion die is 1.25-1.4 mm.

[0025] Preferably, in step d), the shaping and sizing is performed by scraping at a scraping speed of 2 to 10 m / s.

[0026] The present invention also provides a short-process magnesium alloy wire continuous extrusion system, which comprises:

[0027] Continuous extrusion device, comprising:

[0028] An extrusion wheel and its driving mechanism, wherein a circular guide groove is arranged in the center of the extrusion wheel surface along the circumferential direction;

[0029] The sealing guide plate is arc-shaped, and its central angle α is greater than 100°; the sealing guide plate is arranged at the outer edge of the extrusion wheel, and cooperates with the guide groove of the extrusion wheel to form an extrusion cavity; the extrusion cavity corresponding to one end of the sealing guide plate is the inlet of the extrusion cavity, and the sealing guide plate near the inlet side of the extrusion cavity is provided with a feed hole connected to the extrusion cavity; a plug is arranged in the guide groove corresponding to the other end of the sealing guide plate, and cooperates with the end of the sealing guide plate to form an outlet of the extrusion cavity;

[0030] A feeding cylinder, disposed in the feeding hole;

[0031] An extrusion die is arranged at the end of the sealing guide plate and the plug, and is connected to the outlet of the extrusion cavity;

[0032] A protective gas delivery module, comprising an air pump and an air pipe; the air pipe outlet extends to the inlet of the extrusion chamber, and preferably, the air pipe axis is tangent to the top of the extrusion wheel;

[0033] At least one heating module, disposed on the outer edge of the extrusion wheel;

[0034] The temperature measuring module is arranged at the inlet of the extrusion chamber and corresponds to the guide groove of the extrusion wheel;

[0035] The controller, the driving mechanism of the extrusion wheel, the air pump of the protective gas delivery module, the heating module, and the temperature measurement module are all connected to the controller.

[0036] Preferably, the temperature measurement module is a non-contact infrared temperature measurement or a contact thermocouple temperature measurement, and is controlled in linkage with the heating module through a controller.

[0037] Furthermore, it also includes an extrusion pad, which is arranged at the discharge port of the extrusion cavity, and is provided with a through hole connected to the discharge port. The extrusion pad is a split structure, and a accommodating space for placing the extrusion mold is provided in the middle of the extrusion pad.

[0038] Preferably, the extrusion die is a split structure, including a variable diameter die cavity communicating with the extrusion cavity and a fixed diameter die cavity for discharging the wire; the cross-sectional area of ​​the variable diameter die cavity gradually decreases from the extrusion cavity to the fixed diameter die cavity.

[0039] Preferably, the heating module adopts induction heating, and its induction coil is an arc-shaped structure matching the extrusion wheel guide groove, and is a retractable structure that can be extended into the guide groove during heating; preferably, a magnetic conductor is arranged in the induction coil area that can be extended into the guide groove.

[0040] Compared with the prior art, the advantages of the present invention are:

[0041] 1. The existing technology requires hot extrusion to form magnesium rods, and then multiple drawing and intermediate annealing or continuous extrusion to obtain magnesium alloy wires, resulting in low processing efficiency and high production energy consumption.

[0042] The present invention adopts magnesium alloy extrusion material to obtain magnesium alloy wire through a single-pass continuous extrusion process, without the need for hot extrusion of magnesium rods and drawing processes, and has a short preparation process, a simple and stable process, and lower production energy consumption.

[0043] 2. Compared with rod materials, conventional metal granules have slower friction heating, resulting in lower continuous extrusion efficiency, and their large specific surface area leads to oxidation inclusions and other problems.

[0044] The present invention has been studied and practiced and found that the use of non-spherical magnesium alloy extrusion material and the control of the thickness and length of the magnesium alloy extrusion material can effectively reduce the oxidized surface area on the one hand, and on the other hand, compared with the traditional process using nearly spherical particles, the magnesium alloy extrusion material of the present invention is more prone to frictional heating during continuous extrusion deformation, thereby improving the continuous extrusion efficiency of the wire.

[0045] 3. For magnesium alloy bars with high content of strengthening elements such as Ca, RE, and Zn, the traditional process is difficult to extrude and draw plastic deformation, has strict process requirements, and has poor forming stability.

[0046] The present invention adopts cutting and ball milling to adapt to the processing of magnesium alloy extrusion materials of all composition systems, and has no requirements on the size specifications of the ingots; combined with the continuous extrusion system developed by the present invention according to the characteristics of magnesium alloys, stable and efficient preparation of magnesium alloy wires of all composition systems can be achieved.

[0047] 4. The traditional process of preparing magnesium wire has low wire joint strength due to the discontinuity of extrusion, and there is a problem of wire breakage during the wire feeding process.

[0048] The present invention adopts continuous extrusion to directly form magnesium wire. The magnesium alloy is extruded after shear deformation in the extrusion cavity and full fusion, so that a wire structure with fine grains can be obtained, which effectively improves the plasticity of the magnesium alloy and realizes metallurgical bonding of the wire joint. Therefore, it can ensure smooth wire feeding in the welding and fused wire additive manufacturing processes, and the wire is not easy to break during the process.

[0049] In summary, the present invention can greatly simplify the processing steps and preparation process of magnesium alloy wire, significantly improve production efficiency, reduce production energy consumption, improve the wire feeding performance of magnesium alloy wire, and is easy to promote and apply.

[0050] 5. The continuous extrusion system designed in the present invention effectively overcomes the material characteristics of magnesium alloy such as easy oxidation and temperature sensitivity during deformation processing, and realizes stable and efficient extrusion of magnesium alloy wire.

[0051] The existing technology generally adopts the form of online heating of magnesium alloy extrusion materials in order to improve the plastic deformation performance of the continuous extrusion process; however, due to the small specific heat capacity and high thermal conductivity of magnesium alloy, it dissipates heat quickly after contacting with the cold extrusion wheel, so the heating stability is poor and the plastic deformation improvement effect is poor.

[0052] The present invention adopts the method of online heating and dynamic temperature control of the extrusion wheel. After the magnesium alloy extrusion material enters the preheated extrusion wheel guide groove, it can not only quickly reach the hot processing temperature, but also has a more stable heat preservation effect, which significantly improves the extrusion performance of the magnesium alloy. On this basis, the preferred scheme adopts induction heating combined with a contoured structure induction coil to ensure accurate and uniform heating of the extrusion wheel guide groove, and the heating efficiency is higher.

[0053] Compared with conventional continuous extrusion devices, the present invention adopts a sealing guide plate with a central angle α greater than 100°, so that the arc length of the sealing guide plate is longer, the length of the extrusion cavity is increased, and the extrusion material in the extrusion cavity is ensured to obtain more sufficient friction heating and fusion before extrusion, thereby helping to continuously and stably extrude the magnesium alloy wire.

[0054] The present invention provides a gas delivery module to provide a protective atmosphere for the extrusion cavity, thereby avoiding quality problems such as oxidation inclusions in the extruded magnesium wire caused by high-temperature oxidation during the continuous extrusion process of the magnesium alloy extrusion material.

[0055] Compared with conventional continuous extrusion sizing dies, the extrusion die design of the present invention adopts a split variable diameter die cavity, which can effectively reduce the unevenness of metal flow and temperature and obtain magnesium alloy wires with uniform structure and size. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a structural schematic diagram of the continuous extrusion system of the present invention;

[0057] Figure 2 This is a SEM image of the AZ41 magnesium alloy extrusion material obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0058] The present invention is described in detail below with reference to the accompanying drawings and specific implementation modes, but the protection scope of the present invention is not limited thereto.

[0059] The short-process magnesium alloy wire continuous extrusion preparation method of the present invention comprises the following steps:

[0060] a) Preparation of magnesium alloy extrusion materials

[0061] The thickness of magnesium alloy extrusion material is 0.03-0.1mm and the length is 0.3-5mm;

[0062] b) Preheating of extrusion wheel

[0063] Preheating the extrusion wheel of the extrusion device at a temperature of 250-500°C so that the surface of the extrusion wheel is evenly heated; preferably, the preheating is performed by induction heating;

[0064] c) Continuous extrusion

[0065] The inert gas is continuously introduced into the extrusion cavity, and then the magnesium alloy extrusion material is fed into the extrusion cavity. As the extrusion wheel rotates, the magnesium alloy extrusion material is driven through the extrusion die to extrude the wire. Preferably, the inert gas is pre-introduced into the extrusion cavity for 1 to 3 minutes to ensure that the extrusion cavity is filled with inert gas before continuous extrusion is started. Preferably, the inert gas flow rate is 5 to 10 m / s. 3 / h;

[0066] d) Shaping and sizing

[0067] The wire obtained in step c) is subjected to shaping and sizing treatment to obtain a magnesium alloy wire with a final required diameter.

[0068] Preferably, in step a), the ratio of the length to the thickness of the magnesium alloy extrusion material is not less than 5:1.

[0069] Preferably, in step a), the magnesium alloy extrusion material is prepared by: first cutting the magnesium alloy ingot to cut out magnesium alloy chips with a thickness of 0.03 to 0.5 mm; then introducing the magnesium alloy chips into a ball mill, and obtaining magnesium alloy chips as extrusion materials after ball milling, with a thickness of 0.03 to 0.1 mm and a length of 0.3 to 5 mm; preferably, ball milling is performed in an inert atmosphere; preferably, the cutting process is protected by an inert atmosphere throughout the process; more preferably, the inert atmosphere is nitrogen or argon.

[0070] The magnesium alloy extrusion material may also be prepared by other conventional magnesium chip preparation processes, or purchased magnesium alloy chips.

[0071] Preferably, in step a), the ball milling speed is 250-450 rpm, and the ball milling time is 2-6 h.

[0072] Preferably, in step a), a single rolling cutter head with a hydraulic push rod is used to cut the magnesium alloy ingot, and the feed speed is set to 90 to 360 s / 100 mm.

[0073] Preferably, in step c), the temperature of the extrusion wheel is maintained at 350-500° C. during the continuous extrusion process, and preferably, the rotation speed of the extrusion wheel is 2-10 rpm.

[0074] Preferably, in step c), the finished wire has a diameter of 2.0 mm, and the sizing die hole diameter of the extrusion die is 2.05-2.2 mm; the finished wire has a diameter of 1.6 mm, and the sizing die hole diameter of the extrusion die is 1.65-1.8 mm; the finished wire has a diameter of 1.2 mm, and the sizing die hole diameter of the extrusion die is 1.25-1.4 mm.

[0075] Preferably, in step d), the shaping and sizing is performed by scraping at a scraping speed of 2 to 10 m / s.

[0076] See also Figure 1The short-process magnesium alloy wire continuous extrusion system of the present invention comprises: a continuous extrusion device, a protective gas delivery module, at least one heating module, a temperature measurement module, and a controller; wherein,

[0077] The continuous extrusion device comprises:

[0078] An extrusion wheel 1 and its driving mechanism, wherein an annular guide groove 11 is provided in the center of the wheel surface of the extrusion wheel 1 along the circumferential direction;

[0079] The sealing guide plate 2 is arc-shaped, and its central angle α is greater than 100°; the sealing guide plate 2 is arranged at the outer edge of the extrusion wheel 1, and cooperates with the guide groove 11 of the extrusion wheel 1 to form an extrusion cavity 100; the extrusion cavity corresponding to one end of the sealing guide plate 2 is the extrusion cavity inlet 101, and the sealing guide plate 2 near the extrusion cavity inlet 101 is provided with a feed hole 201 connected to the extrusion cavity 100; the guide groove 11 corresponding to the other end of the sealing guide plate 2 is provided with a plug 3, and cooperates with the end of the sealing guide plate 2 to form an extrusion cavity discharge port 102;

[0080] A feeding cylinder 4 is disposed in the feeding hole 201;

[0081] An extrusion die 5 is disposed at the end of the sealing guide plate 2 and the plug 3 and is connected to the extrusion cavity discharge port 102;

[0082] The protective gas delivery module 6 includes an air pump 61 and an air pipe 62; the outlet of the air pipe 62 extends to the inlet 101 of the extrusion chamber, and preferably, the axis of the air pipe 62 is tangent to the top of the extrusion wheel 1;

[0083] At least one heating module 7, disposed on the outer edge of the extrusion wheel 1;

[0084] The temperature measuring module 8 is arranged at the inlet 101 of the extrusion chamber, corresponding to the extrusion wheel guide groove 11;

[0085] A controller (not shown), a driving mechanism of the extrusion wheel, an air pump of the protective gas delivery module, a heating module, and a temperature measurement module are all connected to the controller.

[0086] Preferably, the temperature measurement module 8 is a non-contact infrared temperature measurement or a contact thermocouple temperature measurement, and is controlled in linkage with the heating module through a controller.

[0087] In this embodiment, the temperature measuring module 8 is disposed at the opening between the extrusion wheel 1 and the sealing guide plate 2 to monitor the temperature of the extrusion wheel guide groove 11 and feed back to the (induction) heating module 7 for dynamic temperature regulation.

[0088] Furthermore, it also includes an extrusion pad 9, which is arranged at the discharge port 102 of the extrusion chamber, and is provided with a through hole connected to the discharge port. In addition, the extrusion pad 9 is a split structure, and a receiving space for the extrusion mold 5 is provided in the middle of the extrusion pad 9.

[0089] Preferably, the extrusion die 5 is a split structure, including a variable diameter die cavity communicating with the extrusion cavity and a fixed diameter die cavity for discharging the wire material; the cross-sectional area of ​​the variable diameter die cavity gradually decreases from the extrusion cavity to the fixed diameter die cavity.

[0090] Preferably, the heating module 7 is an induction heating method, and its induction coil 71 is an arc structure matching the extrusion wheel guide groove 11, and is a retractable structure that can be extended into the guide groove 11 during heating, and a magnetic conductor 72 is arranged in the induction coil area extending into the guide groove 11.

[0091] Example 1

[0092] Preparation of AZ41 grade (Mg-4Al-1Zn) magnesium alloy wire with a diameter of φ1.2 mm, the specific preparation steps include:

[0093] a) Ingot chip cutting: A single rolling cutter head with a hydraulic push rod is used to cut the AZ41 magnesium alloy ingot under the protection of nitrogen throughout the process. By adjusting the cutting feed speed, AZ41 magnesium alloy chips with a thickness of 0.2 to 0.5 mm are cut out;

[0094] b) Ball milling: The obtained AZ41 magnesium alloy chips are introduced into a sealed ball mill and ball milled at normal pressure in nitrogen at a ball milling speed of 250-290 rpm for 3 h. The AZ41 magnesium alloy chips 300 obtained after ball milling have a thickness of 0.03-0.06 mm and a length of 0.4-0.7 mm. The obtained AZ41 magnesium alloy chips are as follows: Figure 2 As shown; the magnesium alloy chips after processing are preferably stored in vacuum packaging as extrusion materials;

[0095] c) Preheating of the extrusion wheel: Use the (induction) heating module to preheat the extrusion wheel, and start the extrusion wheel to rotate clockwise at the same time, so that the surface of the extrusion wheel is evenly heated, and the temperature is measured by the infrared thermometer feedback; the preheating setting temperature is 250℃;

[0096] d) Continuous extrusion: After the preheating temperature of the extrusion wheel is reached, nitrogen is pre-flowed into the extrusion cavity for 1 minute; then the obtained magnesium alloy extrusion material 300 is continuously fed into the extrusion cavity, and the extrusion wheel is started to drive the magnesium alloy extrusion material to move forward along the extrusion cavity; after reaching the plug, the magnesium alloy extrusion material is heated up and melted by friction and fully sheared and deformed, and finally 400 wires are extruded through the extrusion die; the extrusion wheel speed is maintained at 2-4rpm, the extrusion wheel temperature is maintained at 350-400℃, and the diameter of the sizing die hole of the extrusion die used is 1.25mm;

[0097] e) Shaping and sizing: The obtained wire is subjected to room temperature scraping treatment, the scraping die diameter is 1.2 mm, and the scraping speed is 4 to 6 m / s to obtain the AZ41 magnesium alloy wire of the final required diameter.

[0098] Example 2

[0099] Preparation of Mg1911C grade (Mg-9Al-1Zn-2Ca) high flame retardant magnesium alloy wire with a diameter of φ1.6 mm, the specific preparation steps include:

[0100] a) Ingot broaching: A conventional multi-tooth broach is used to broach the Mg1911C magnesium alloy ingot under argon protection throughout the process to obtain Mg1911C magnesium alloy chips with a thickness of 0.1 to 0.5 mm;

[0101] b) Ball milling: The obtained Mg1911C magnesium alloy chips are introduced into a sealed ball mill and ball milled at normal pressure in argon gas at a ball milling speed of 300-380 rpm for 4 hours; the magnesium alloy chips obtained after ball milling have a thickness of 0.05-0.08 mm and a length of 0.7-3 mm. The obtained Mg1911C magnesium alloy chips are vacuum packed and stored as extrusion materials;

[0102] c) Preheating of the extrusion wheel: Use the induction heating module to preheat the extrusion wheel, and start the extrusion wheel to rotate clockwise at the same time, so that the surface of the extrusion wheel is evenly heated, and the temperature is measured by the infrared thermometer feedback; the preheating setting temperature is 350℃;

[0103] d) Continuous extrusion: After the preheating temperature of the extrusion wheel is reached, argon gas is pre-flowed into the extrusion cavity for 3 minutes; then the obtained Mg1911C magnesium alloy extrusion material is continuously fed into the extrusion cavity, and the extrusion wheel is started to drive the magnesium alloy extrusion material 300 to move forward along the extrusion cavity; after reaching the plug, the magnesium alloy extrusion material is heated up, melted and fully sheared and deformed by friction, and finally a wire 400 is extruded through the extrusion die; the extrusion wheel speed is maintained at 6-8rpm, the extrusion wheel temperature is maintained at 380-420°C, and the diameter of the sizing die hole of the extrusion die used is 1.7mm;

[0104] e) Shaping and sizing: The obtained magnesium alloy wire 400 is subjected to room temperature scraping treatment, the scraping die diameter is 1.6 mm, and the scraping speed is 3-5 m / s to obtain the Mg1911C magnesium alloy wire of the final required diameter.

[0105] Example 3

[0106] Preparation of φ2.0mm diameter VW94 grade (Mg-9Gd-4Y-1Zn-0.3Zr) high-strength magnesium alloy wire, the specific preparation steps include:

[0107] a) Ingot chip cutting: A single rolling cutter head with a hydraulic push rod is used to cut the VW94 magnesium alloy ingot under the protection of argon gas throughout the process. By adjusting the cutting feed speed, VW94 magnesium alloy chips with a thickness of 0.05 to 0.13 mm are cut out;

[0108] b) Ball milling: The obtained VW94 magnesium alloy chips are introduced into a sealed ball mill and ball milled at normal pressure in argon gas at a ball milling speed of 380-430 rpm for 5 hours; the magnesium alloy chips 300 obtained after ball milling have a thickness of 0.06-0.1 mm and a length of 1-4.5 mm. The obtained VW94 magnesium alloy chips are vacuum packaged and stored as extrusion materials;

[0109] c) Preheating of extrusion wheel: Use induction heating module to preheat the extrusion wheel, and start the extrusion wheel to rotate clockwise at the same time, so that the surface of the extrusion wheel is evenly heated, and the temperature of the extrusion wheel groove is fed back by thermocouple temperature probe; the preheating setting temperature is 430℃;

[0110] d) Continuous extrusion: After the preheating temperature of the extrusion wheel is reached, argon gas is pre-flowed into the extrusion cavity for 2 minutes; then the obtained VW94 magnesium alloy extrusion material is continuously fed into the extrusion cavity, and the extrusion wheel is started to drive the magnesium alloy extrusion material to move forward along the extrusion cavity; after reaching the plug, the magnesium alloy extrusion material is heated and melted by friction and fully sheared and deformed, and finally 400 magnesium alloy wire is extruded through the extrusion die; the extrusion wheel speed is maintained at 4-5rpm, the extrusion wheel temperature is maintained at 430-460℃, and the diameter of the sizing die hole of the extrusion die used is 2.15mm;

[0111] e) Shaping and sizing: The obtained magnesium alloy wire 400 is subjected to room temperature scraping treatment, the scraping die diameter is 2 mm, and the scraping speed is 5-8 m / s to obtain the VW94 magnesium alloy wire of the final required diameter.

[0112] Example 4

[0113] Preparation of AZ80 grade (Mg-8Al-0.5Zn) magnesium alloy wire with a diameter of φ1.6 mm, the specific preparation steps include:

[0114] a) Preparation of magnesium alloy chips: Purchase AZ80 magnesium alloy chips with a thickness of 0.1-0.5 mm and a length of 2-5 mm;

[0115] b) Ball milling: AZ80 magnesium alloy chips are introduced into a sealed ball mill and ball milled at normal pressure in argon gas at a ball milling speed of 300-450 rpm for 3 hours; the magnesium alloy chips 300 obtained after ball milling have a thickness of 0.05-0.1 mm and a length of 0.5-5 mm. The obtained AZ80 magnesium alloy chips are vacuum packaged and stored as extrusion materials;

[0116] c) Preheating of extrusion wheel: Use induction heating module to preheat the extrusion wheel, and start the extrusion wheel to rotate clockwise at the same time, so that the surface of the extrusion wheel is evenly heated, and the temperature of the extrusion wheel groove is fed back by thermocouple temperature probe; the preheating setting temperature is 340℃;

[0117] d) Continuous extrusion: After the preheating temperature of the extrusion wheel is reached, nitrogen is pre-flowed into the extrusion cavity for 2 minutes; then the obtained AZ80 magnesium alloy extrusion material is continuously fed into the extrusion cavity, and the extrusion wheel is started to drive the magnesium alloy extrusion material to move forward along the extrusion cavity; after reaching the plug, the magnesium alloy extrusion material is heated up, melted and fully sheared and deformed by friction, and finally 400 magnesium alloy wires are extruded through the extrusion die; the extrusion wheel speed is maintained at 3-7 rpm, the extrusion wheel temperature is maintained at 350-380°C, and the diameter of the sizing die hole of the extrusion die used is 1.70 mm;

[0118] e) Shaping and sizing: The obtained magnesium alloy wire 400 is subjected to room temperature scraping treatment, the scraping die diameter is 1.6 mm, and the scraping speed is 4 to 9 m / s to obtain the AZ80 magnesium alloy wire of the final required diameter.

Claims

1. A short-process magnesium alloy wire continuous extrusion preparation method, characterized in that: The following steps are involved: a) Preparation of magnesium alloy extrusion materials The thickness of magnesium alloy extrusion material is 0.03-0.1mm and the length is 0.3-5mm; b) Preheating of extrusion wheel Preheating the extrusion wheel of the extrusion device at a temperature of 250-500°C so that the surface of the extrusion wheel is evenly heated; preferably, the preheating is performed by induction heating; c) Continuous extrusion The extrusion chamber of the extrusion device is continuously introduced with inert gas, and then the magnesium alloy extrusion material is fed into the extrusion chamber, and the magnesium alloy chips are driven to extrude the wire through the extrusion die as the extrusion wheel rotates; preferably, the extrusion chamber is pre-introduced with inert gas for 1 to 3 minutes to ensure that the extrusion chamber is filled with inert gas before continuous extrusion is started; preferably, the inert gas flow rate is 5 to 10 m / s. 3 / h; d) Shaping and sizing The wire obtained in step c) is subjected to shaping and sizing treatment to obtain a magnesium alloy wire with a final required diameter.

2. The short-process magnesium alloy wire continuous extrusion preparation method according to claim 1, characterized in that: In step a), the ratio of the length to the thickness of the magnesium alloy extrusion material is not less than 5:

1.

3. The short-process magnesium alloy wire continuous extrusion preparation method according to claim 1 or 2, characterized in that: In step a), the magnesium alloy extrusion material is prepared by: first cutting the magnesium alloy ingot to cut out magnesium alloy chips with a thickness of 0.03 to 0.5 mm; then introducing the magnesium alloy chips into a ball mill, and obtaining magnesium alloy chips as extrusion material after ball milling; preferably, ball milling is carried out in an inert atmosphere; preferably, the cutting process is protected by an inert atmosphere throughout the process; more preferably, the inert atmosphere is nitrogen or argon.

4. The short-process magnesium alloy wire continuous extrusion preparation method according to claim 3, characterized in that: In step a), the magnesium alloy ingot is cut by using a single rolling cutter head with a hydraulic push rod, and the feed speed is set to 90-360s / 100mm.

5. The short-process magnesium alloy wire continuous extrusion preparation method according to claim 1, 2, 3 or 4, characterized in that: In step a), the ball milling speed is 250-450 rpm, and the ball milling time is 2-6 hours.

6. The short-process continuous extrusion preparation method of magnesium alloy wire according to claim 1, characterized in that: In step c), the temperature of the extrusion wheel is maintained at 350-500° C. during the continuous extrusion process, and preferably, the rotation speed of the extrusion wheel is 2-10 rpm.

7. The short-process magnesium alloy wire continuous extrusion preparation method according to claim 1 or 6, characterized in that: In step c), the finished wire has a diameter of 2.0 mm, and the sizing die hole diameter of the extrusion die is 2.05-2.2 mm; the finished wire has a diameter of 1.6 mm, and the sizing die hole diameter of the extrusion die is 1.65-1.8 mm; the finished wire has a diameter of 1.2 mm, and the sizing die hole diameter of the extrusion die is 1.25-1.4 mm.

8. The short-process magnesium alloy wire continuous extrusion preparation method according to claim 1, characterized in that: In step d), the shaping and sizing is carried out by scraping, and the scraping speed is 2 to 10 m / s.

9. A short-process magnesium alloy wire continuous extrusion system, characterized in that: include: Continuous extrusion device, comprising: An extrusion wheel and its driving mechanism, wherein a circular guide groove is arranged in the center of the extrusion wheel surface along the circumferential direction; The sealing guide plate is arc-shaped, and its central angle α is greater than 100°; the sealing guide plate is arranged at the outer edge of the extrusion wheel, and cooperates with the guide groove of the extrusion wheel to form an extrusion cavity; the extrusion cavity corresponding to one end of the sealing guide plate is the inlet of the extrusion cavity, and the sealing guide plate near the inlet side of the extrusion cavity is provided with a feed hole connected to the extrusion cavity; a plug is arranged in the guide groove corresponding to the other end of the sealing guide plate, and cooperates with the end of the sealing guide plate to form an outlet of the extrusion cavity; A feeding cylinder, disposed in the feeding hole; An extrusion die is arranged at the end of the sealing guide plate and the plug, and is connected to the discharge port of the extrusion cavity; A protective gas delivery module, comprising an air pump and an air pipe; the air pipe outlet extends to the inlet of the extrusion chamber, and preferably, the air pipe axis is tangent to the top of the extrusion wheel; At least one heating module is arranged at the outer edge of the extrusion wheel; preferably, the heating module is induction heating, and its induction coil is an arc structure matching the guide groove of the extrusion wheel, and is a retractable structure that can be extended into the guide groove during heating; more preferably, a magnetic conductor is arranged in the induction coil area that can be extended into the guide groove; The temperature measuring module is arranged at the inlet of the extrusion chamber and corresponds to the guide groove of the extrusion wheel; The controller is connected to the driving mechanism of the extrusion wheel, the air pump of the protective gas delivery module, the heating module and the temperature measurement module.

10. The short-process magnesium alloy wire continuous extrusion system according to claim 9, characterized in that: The temperature measurement module is a non-contact infrared temperature measurement or a contact thermocouple temperature measurement, and is linked and controlled by a controller and a heating module.

11. The short-process magnesium alloy wire continuous extrusion system according to claim 9, characterized in that: It also includes an extrusion pad, which is arranged at the discharge port of the extrusion chamber and has a through hole connected to the discharge port. The extrusion pad is a split structure, and a accommodating space for inserting the extrusion mold is provided in the middle of the extrusion pad. Preferably, the extrusion mold is a split structure, including a variable diameter mold cavity connected to the extrusion chamber and a fixed diameter mold cavity for wire discharge. The cross-sectional area of ​​the variable diameter mold cavity gradually decreases from the extrusion chamber to the fixed diameter mold cavity.

Images