A large-size high-alloy magnesium-rare earth alloy round ingot semi-continuous casting device

Abstract

The application belongs to the technical field of semi-continuous casting device, and relates to a large-specification high-alloyed magnesium-rare earth alloy round ingot semi-continuous casting device.The device comprises a crystallizer, an ingot base and a flow divider.A plurality of multi-stage circular-arc bosses with gradually increasing radiuses from top to bottom are arranged on the inner bottom surface of the ingot base, so as to promote the high-temperature melt to flow to the edge part quickly and reduce the temperature difference between the center part and the edge part.The flow divider comprises a vertical pipe and a plurality of fan-shaped flow dividing zones arranged along the circumference of the vertical pipe.The high-temperature melt flows into the flow dividing zones from the vertical pipe, flows out of the flow dividing zones, enters the crystallizer, and makes the radial flow of the high-temperature melt more uniform.The application significantly improves the uniformity of melt flow and temperature, and the uniformity of solute and structure of the ingot, reduces the tendency of thermal cracking, and reduces the cracking problem in the casting process.The large-specification high-strength magnesium alloy ingot prepared by the application is free of cracks, and the structure is free of segregation, slag inclusion and other defects, and the qualified rate is greater than 98%.

Description

Technical Field

[0001] The invention belongs to the technical field of semi-continuous casting devices and relates to a semi-continuous casting device for large-scale high-alloyed magnesium rare earth alloy ingots. Background Art

[0002] With the rapid development of fields such as aerospace and rail transportation, the industry's demand for lightweight engineering materials is increasing, and the demand for larger and higher-quality magnesium alloy components is also increasing rapidly. The precursors of large-scale magnesium alloy forgings require high-quality large-scale ingots. However, the high rare earth element content in high-strength and toughness magnesium alloys leads to more quality problems, which greatly limits the application of magnesium alloys. Among the many quality problems, two are particularly serious. The first is segregation. As a defect that persists throughout the casting process, segregation is difficult to eliminate through heat treatment. This type of defect is more serious in large-scale ingots with high rare earth content. It will reduce the performance of the ingot and make subsequent deformation processes more difficult to implement. The second is casting cracking. Highly alloyed ingots, especially large-scale ingots, are more prone to hot and cold cracking during the casting process, which greatly affects the yield of the ingot.

[0003] In semi-continuous casting production, mechanical stirring and electromagnetic stirring are often used to effectively improve the uniformity of melt flow inside the crystallizer. However, such methods are less effective in the production of large-scale, high-strength and tough magnesium alloy ingots. First, the chemical properties of magnesium alloys are more active. Even under a protective atmosphere, slight fluctuations in the melt may cause melt combustion, which is accompanied by great production safety issues. Second, electromagnetic stirring uses alternating current to form an induced current inside the melt, and achieves the stirring effect through the Lorentz force. However, due to the skin effect, electromagnetic stirring has limited stirring effect on the core position of large-scale ingots.

[0004] Given the unique characteristics of magnesium alloy production, passive diversion is currently a more reasonable method. However, its effectiveness depends largely on the structural rationality of the diversion device and its compatibility with process parameters. Cracking is particularly prone to occur when producing large, highly alloyed magnesium-rare earth alloy ingots. Therefore, it is necessary to develop a new passive diversion device specifically for large, high-strength and tough magnesium alloy ingots to improve melt flow uniformity within the mold, reduce casting segregation, and avoid casting cracking. Summary of the Invention

[0005] To address the problems of ingot cracking and poor surface quality that can occur during the production of existing large-scale, high-strength and tough magnesium alloy ingots, the present invention provides a semi-continuous casting apparatus for large-scale, high-alloyed magnesium-rare-earth alloy ingots. This apparatus effectively improves the uniformity of melt flow within the crystallizer during casting, reduces temperature gradients between the core and surface of the ingot, flattens the liquid cavitation, significantly improves segregation, and significantly reduces ingot cracking. The magnesium alloy ingots produced using this apparatus exhibit excellent surface quality and uniform internal structure. After subsequent normal processing, the resulting products can be widely used in aviation, aerospace, and other military industries, further enhancing product stability.

[0006] The technical solutions of the present invention are as follows:

[0007] The present invention provides a semi-continuous casting device for large-scale high-alloyed magnesium rare earth alloy ingots, comprising a cylindrical crystallizer, a starter base that can be sleeved with the crystallizer, and a diverter plate arranged above the crystallizer for guiding the melt, wherein the starter base can move relative to the crystallizer, wherein:

[0008] A multi-stage arc boss with a radius increasing from top to bottom is provided on the inner bottom surface of the ingot base, which is used to promote the high-temperature melt to flow to the edge of the molten pool faster and reduce the temperature difference between the center of the molten pool and the edge of the molten pool; the diverter plate includes a vertical pipe and a plurality of fan-shaped diverter areas, and the diverter areas are arranged along the circumference of the vertical pipe. The high-temperature melt flows from the vertical pipe, flows out through the diverter area, and enters the crystallizer, so that the radial flow of the high-temperature melt is more uniform.

[0009] In one embodiment of the present invention, it is preferred that the multi-stage arc boss is a double-stage arc boss, including a primary arc boss connected to the bottom surface of the ingot base, and a secondary arc boss on the primary arc boss. The primary arc boss and the bottom surface of the ingot base are smoothly transitioned, and the primary arc boss and the secondary arc boss are also smoothly transitioned. It is further preferred that the radius of the primary arc boss is 400-600mm, the radius of the secondary arc boss is 100-150mm, and the heights of the primary arc boss and the secondary arc boss are both 10-20mm.

[0010] In one embodiment of the present invention, preferably, the crystallizer includes a crystallizer inner sleeve and a crystallizer outer shell, a platform edge is provided along the circumference of the crystallizer inner sleeve, the top of the crystallizer outer shell is provided with an annular platform that cooperates with the platform edge, the annular platform is located below the platform edge, and the crystallizer outer shell is further provided with an outer shell connected to the annular platform for embedding the crystallizer inner sleeve.

[0011] In one embodiment of the present invention, preferably, an annular cooling water trough is provided between the crystallizer shell and the crystallizer inner sleeve, and a water inlet pipe is provided on the crystallizer shell, and the water inlet pipe is connected to the cooling water trough.

[0012] In one embodiment of the present invention, preferably, the water inlet pipes are provided on both sides of the crystallizer shell.

[0013] In one embodiment of the present invention, preferably, secondary cooling water outlet holes are provided along the lower side of the inner sleeve of the crystallizer, and the water outlet holes are arranged obliquely, corresponding to the moving direction of the ingot during semi-continuous casting.

[0014] In one embodiment of the present invention, preferably, the shape of the inner sleeve of the crystallizer is a trumpet shape that is wide at the top and narrow at the bottom, and the inclination angle is 1-6°.

[0015] In one embodiment of the present invention, preferably, an oil inlet pipe is provided between the platform edge and the annular platform, an oil groove is provided along the circumference of the annular platform, and an oil lubrication spray hole communicating with the oil groove is provided on the platform edge.

[0016] In one embodiment of the present invention, preferably, the oil inlet pipes are provided on both sides of the inner sleeve of the crystallizer.

[0017] In one embodiment of the present invention, preferably, the number of the diversion areas is six, and further preferably, the six diversion areas are evenly distributed in the circumferential direction of the vertical pipe.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention provides a semi-continuous casting device for large-scale high-alloyed magnesium rare earth alloy ingots. The melt diversion during the casting process is achieved by the diverter plate above the crystallizer, which causes less oxidation and combustion compared to other active diversion methods. At the same time, compared with the traditional diverter plate and the ingot base, the diversion effect is better. After the present invention adopts the diverter plate with a six-way diverter tube and the ingot base with a double boss, the uniformity of the flow of the magnesium alloy melt in the crystallizer during the casting process is significantly improved, the uniformity of the melt temperature is improved, the uniformity of the solute and structure of the ingot is effectively improved, and the tendency of thermal cracking is reduced, thereby reducing the cracking problem during the casting process. The large-scale high-strength and tough magnesium alloy ingots prepared by the method of the present invention are free of cracks, and the ingot structure is free of defects such as segregation and slag inclusions, and the ingot qualification rate is greater than 98%.

[0020] The high-performance magnesium alloy blank produced by the present invention has better internal quality and flaw detection pass rate than existing magnesium alloy products after undergoing various subsequent plastic forming processes. The corresponding products can be widely used in aviation, aerospace and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG1 is a front view of a semi-continuous casting device for large-scale high-alloyed magnesium-rare earth alloy ingots in operation according to an embodiment of the present invention;

[0022] FIG2 is a front view of a semi-continuous casting apparatus for large-scale high-alloyed magnesium-rare earth alloy ingots according to an embodiment of the present invention;

[0023] FIG3 is a front view of the starter base 2 according to an embodiment of the present invention;

[0024] FIG4 is a top view of the diverter plate 3 according to an embodiment of the present invention;

[0025] FIG5 is a front view of a starter base of a conventional semi-continuous casting device;

[0026] FIG6 is a schematic structural diagram of a diverter plate of a conventional semi-continuous casting device;

[0027] Figure 7 Graph showing the distribution of Gd content along the diameter direction of ingots cast using the semi-continuous casting apparatus of the present invention and a conventional semi-continuous casting apparatus;

[0028] FIG8 is a schematic diagram of an ingot produced by a semi-continuous casting apparatus for a large-scale high-alloyed magnesium-rare earth alloy ingot according to an embodiment of the present invention.

[0029] Markings in the figure: 1-crystallizer, 11-crystallizer inner sleeve, 111-platform edge, 112-water outlet, 113-oil lubrication nozzle, 12-crystallizer shell, 121-annular platform, 122-shell, 123-water inlet pipe, 124-oil tank, 2-starting spindle base, 21-multi-stage arc boss, 211-first-stage arc boss, 212-second-stage arc boss, 3-diverter plate, 31-vertical pipe, 32-diverter area, 4-cooling water tank, 5-oil inlet pipe. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0031] The following description sets forth numerous specific details to facilitate a thorough understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific implementations disclosed below.

[0032] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0033] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or welding connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In addition, the descriptions of "primary" and "secondary" in this invention are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "primary" and "secondary" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this invention.

[0035] like Figures 1 to 4 As shown, a semi-continuous casting device for a large-scale high-alloyed magnesium rare earth alloy ingot according to an embodiment of the present invention has a diameter of ≥500 mm. The device comprises a cylindrical crystallizer 1, an ingot starter base 2 that can be mounted on the crystallizer 1, and a diverter plate 3 provided above the crystallizer 1 for guiding the melt. The ingot starter base 2 can move relative to the crystallizer 1, wherein:

[0036] A multi-stage arc boss 21 with a radius increasing from top to bottom is provided on the inner bottom surface of the ingot base 2, which is used to promote the high-temperature melt to flow to the edge of the molten pool faster and reduce the temperature difference between the center of the molten pool and the edge of the molten pool; the diverter plate 3 includes a vertical pipe 31 and a plurality of fan-shaped diverter areas 32, and the diverter areas 32 are arranged along the circumference of the vertical pipe 31. The high-temperature melt flows from the vertical pipe 31, flows out through the diverter area 32, and enters the crystallizer 1, so that the radial flow of the high-temperature melt is more uniform.

[0037] When in use, first install the crystallizer 1 on the semi-continuous casting platform, seal the ingot base 2 and the crystallizer 1 with asbestos rope, and connect cooling water with a cooling water flow rate of 100-200L / min. Lubricating oil seeps out from the oil outlet 5 above the crystallizer. After the water flow is stable and the equipment is baked, the magnesium alloy melt flows out from the furnace guide pipe and is introduced into the crystallizer through the diverter plate 3. After the melt level rises 80-100mm and submerges the diverter plate 3, casting begins. The casting speed is set to 25-35mm / min. The ingot, metal liquid-solid two-phase region, metal melt and metal melt liquid level are formed in sequence above the ingot base 2 until the casting is completed. The entire casting process is carried out under a protective atmosphere of nitrogen and sulfur hexafluoride.

[0038] The present invention provides a multi-stage arc boss 21 on the inner bottom surface of the ingot starter base 2. When the high-temperature melt falls into the molten pool, due to the height difference of the bottom surface, the high-temperature melt can flow to the edge of the molten pool more quickly, reducing the temperature difference between the center and the edge of the molten pool. This can effectively improve the uniformity of the melt temperature during the bottoming stage, reduce the stress at the bottom of the ingot, reduce the occurrence of cracks at the bottom of the ingot, and significantly reduce the cracks in the product. In addition, a number of diversion areas 32 are provided along the circumference of the diversion plate 3, shortening the diversion distance of the high-temperature melt and making the radial flow distribution more uniform. Therefore, the present invention can effectively improve the macrosegregation of the ingot and reduce quality problems such as ingot cracking through the synergistic effect of the four-way diversion area 32 and the ingot starter base with the multi-stage arc boss 21.

[0039] In another embodiment of the present invention, the diverter plate 3 can be made of stainless steel. A vertical pipe 31 is threadedly connected to the furnace's draft tube (not labeled in the figure). High-temperature melt flows from the furnace through the draft tube and into the vertical pipe 31. To prevent melt leakage during the casting process, the threaded connection is sealed with talcum powder and water glass. Furthermore, to enhance the connection strength between the vertical pipe 31 and the diverter area 32, several reinforcing ribs (not labeled in the figure), such as steel wires, are provided between the vertical pipe 31 and the diverter plate 3.

[0040] The diversion area 32 is a fan-shaped square tube, whose inner diameter is the same as that of the vertical tube 31, which is 30-40 mm, and whose outer diameter is the same as that of the diversion plate 3. The diameter of the diversion plate 3 can be 60-90 mm.

[0041] The multi-stage arc boss 21 is preferably a double-stage arc boss, comprising a primary arc boss 211 connected to the bottom surface of the starter base 2, and a secondary arc boss 212 located above the primary arc boss 211. Furthermore, it is preferably configured such that the primary arc boss 211 smoothly transitions to the secondary arc boss 212, and the primary arc boss 211 also smoothly transitions to the bottom surface of the starter base 2.

[0042] Among them, the parameter settings of the first-level arc boss 211 and the second-level arc boss 212 can be as follows, which is not limited by the present invention and can be set specifically according to actual working conditions: the radius of the first-level arc boss 211 is 400-600mm, the radius of the second-level arc boss 212 is 100-150mm, and the heights of the first-level arc boss 211 and the second-level arc boss 212 are both 10-20mm.

[0043] In another embodiment of the present invention, the crystallizer 1 includes a crystallizer inner sleeve 11 and a crystallizer outer sleeve 12. A platform edge 111 is provided along the circumference of the crystallizer inner sleeve 11. The top of the crystallizer outer sleeve 12 is provided with an annular platform 121 that cooperates with and is embedded in the platform edge 111. The annular platform 121 is located below the platform edge 111. The crystallizer outer sleeve 12 is further provided with an outer shell 122 connected to the annular platform 121 for embedding the crystallizer inner sleeve 11. The annular platform 121 and the outer shell 122 are designed to be integrally formed.

[0044] In another embodiment of the present invention, an annular cooling water trough 4 is provided between the crystallizer shell 12 and the crystallizer inner sleeve 11, and a water inlet pipe 123 is provided on the crystallizer shell. The water inlet pipe 123 is connected to the cooling water trough 4 for cooling the ingot.

[0045] Optionally, the water inlet pipe 123 is provided on both sides of the crystallizer shell 12 .

[0046] In another embodiment of the present invention, secondary cooling water outlets 112 are provided along the underside of the mold inner sleeve 11. These outlets 112 are inclined, aligning with the direction of ingot movement during semi-continuous casting, to provide secondary cooling for the ingot and increase its cooling rate. In this embodiment, the provision of the cooling water trough 4 and the water outlets 112 enables both primary and secondary cooling of the ingot.

[0047] In another embodiment of the present invention, preferably, the shape of the inner sleeve 11 of the crystallizer is a trumpet shape that is wide at the top and narrow at the bottom, with an inclination angle of 1-6 degrees, so as to avoid that during the casting process, due to the cooling and shrinkage of the ingot, the ingot and the crystallizer cannot effectively contact each other, the cooling intensity is reduced, and the initial solidification shell on the surface of the ingot is remelted, causing serious segregation and reducing the surface quality of the ingot.

[0048] In order to facilitate installation and avoid stress concentration, in the embodiment of the present invention, the diameter of the top end of the dummy base 2 is 30-50 mm larger than the bottom diameter, with an angled step transition in the middle. The dummy base 2 can be made of stainless steel.

[0049] As for the material of the inner sleeve 11 of the crystallizer, copper can be selected and the inner wall thickness is designed to be 10-15 mm.

[0050] In another embodiment of the present invention, an oil inlet conduit 5 is provided between the platform edge 111 and the annular platform 121. An oil groove 124 is provided along the circumference of the annular platform 121. Oil lubrication nozzles 113 are provided on the platform edge 111, communicating with the oil groove 124. A plurality of oil lubrication nozzles 113 are spaced circumferentially around the platform edge 111, the specific number of which is determined based on operating conditions. Lubricating oil is delivered to the interior of the crystallizer through the oil inlet conduit 5 and the oil lubrication nozzles 113, forming an oil film on the mold surface. This significantly reduces surface defects such as cold shuts and pull marks, thereby improving the surface quality of the ingot.

[0051] Optionally, the oil inlet pipe 5 is provided on both sides of the crystallizer inner sleeve 11 .

[0052] In another embodiment of the present invention, the number of the diversion areas 32 is six. Furthermore, the six diversion areas 32 may be evenly distributed on the circumference of the vertical pipe 31 .

[0053] The present invention first installs the crystallizer 1 on the semi-continuous casting platform, uses the ingot base 2 and the asbestos rope to seal the bottom of the crystallizer inner sleeve 11, and passes the cooling water into the cooling water tank 4. The oil pump is turned on. The oil tank 124 is below the crystallizer inner sleeve 11. The crystallizer inner sleeve 11 is provided with an oil lubrication spray hole 113. The cooling water tank 4 is in the gap between the crystallizer shell 12 and the inner sleeve 11. The assembly gap between the oil tank 3 and the water tank 6 is sealed by a rubber ring. Finally, the cooling water is sprayed out from the cooling water outlet 112 below the crystallizer. The water flow rate is 120 L / min, lubricating oil seeps out from the oil lubrication nozzle 113 on the inner sleeve 11 of the crystallizer, and after the water flow is stable and the equipment is baked; the magnesium alloy melt is introduced into the inner sleeve 11 of the crystallizer from the guide pipe through the diverter plate 3, and casting begins after the melt level rises 80-100mm. The casting speed is set to 25-35mm / min, and the ingot, metal liquid-solid two-phase region, metal melt and metal melt liquid level are formed in sequence above the ingot base 2 until the casting is completed. The whole process needs to be carried out under the protective atmosphere of nitrogen and sulfur hexafluoride.

[0054] Example

[0055] The following describes in detail a large-scale high-alloyed magnesium rare earth alloy semi-continuous casting device for a round ingot of Mg-10Gd-3Y-3Zn-0.5Zr magnesium rare earth alloy of the present invention, taking a large-scale φ510mm semi-continuous casting ingot as an example:

[0056] (1) Casting preparation stage:

[0057] like Figures 2 and 3As shown, the starter base 2 is raised, sleeved on the inner sleeve 11 of the crystallizer, and sealed with asbestos rope. After the sealing is completed, the inner sleeve 11 of the crystallizer is baked.

[0058] like Figure 1 and Figure 4 As shown, the vertical pipe 31 of the diverter plate 3 is threadedly connected to the furnace guide pipe (not marked in the figure), and the threaded connection is sealed with talcum powder and water glass and then baked.

[0059] Turn on the water pump and wait until the water pressure stabilizes at 3-4kg / cm 2 Finally, the preparation work is completed when the melt temperature reaches 695-705℃.

[0060] (2) Casting start stage:

[0061] The furnace control valve is opened, and the melt in the furnace flows through the furnace guide pipe under the action of static pressure, passes through the diverter plate 3, and flows into the crystallizer after diversion.

[0062] When the melt level in the mold reaches the bottom of the diverter tray 3, casting begins. The water flow rate is adjusted to 160-200 L / min, and the casting speed is controlled at 35-40 mm / min. During this process, it is necessary to promptly clean the scum on the surface of the melt in the mold to prevent internal slag from becoming a crack source and causing ingot cracking. After contacting the mold, the melt quickly forms a solidified shell and begins to move downward under the action of gravity, following the ingot base 2.

[0063] (3) Casting stabilization stage: After the casting process stabilizes, the liquid level is gradually controlled to be 20-30 mm above the diverter plate. The ingot with a solidified shell formed on the surface is rapidly cooled after passing through the cooling water area.

[0064] (4) Casting end stage:

[0065] When the ingot length reaches the required length, the furnace control valve is closed and casting is stopped when no more melt flows into the crystallizer. The casting is completed when the ingot slowly cools and moves until it separates from the crystallizer.

[0066] Comparative Example

[0067] The comparative example also takes a large-size φ510mm Mg-10Gd-3Y-3Zn-0.5Zr magnesium rare earth alloy semi-continuous ingot as an example. The structure of the ingot casting device and the preparation method used in the comparative example are the same as those in Example 1. The difference is that 1) using Figure 5 The ingot base shown is a conventional ingot base without a boss; 2) The one used is Figure 6 Conventional diverter plate shown.

[0068] Compared with the embodiments, 1) the conventional ingot guide base without a boss, during the discharge process, the high-temperature melt in the middle can only flow slowly to the edge of the base, which increases the temperature difference at the bottom of the ingot during the discharge and bottoming stage. The obtained product is prone to cracks, and it is difficult to obtain a large-sized magnesium alloy ingot with good quality. The improved ingot guide base of the present invention can make the high-temperature melt flow to the edge more quickly, reduce the temperature difference between the center and the edge, and thus reduce the phenomenon of cracks. 2) During the casting process of the conventional diverter disk, the radial melt flow rate of the diverter disk is difficult to control, there is obvious temperature unevenness, and the diversion effect is poor. During the casting process, the improved diverter disk of the present invention has a short diversion stroke and a more uniform radial flow distribution, which effectively improves the macro segregation of the ingot and reduces quality problems such as ingot cracking.

[0069] After casting a large-size Mg-10Gd-3Y-3Zn-0.5Zr magnesium rare earth alloy ingot of φ510mm using the embodiment and comparative example, the content of the main alloy element Gd along the ingot diameter direction was measured using a direct reading spectrometer. The results are as follows: Figure 7 As shown, it can be found that the segregation degree of the ingot produced by the conventional device is more serious than that of the ingot obtained by the device of the present invention.

[0070] Figure 8 The Mg-10Gd-3Y-3Zn-0.5Zr magnesium rare earth alloy ingot with a diameter of 510 mm produced by the device of the present invention has a smooth surface and is free of defects such as cracks.

[0071] The present invention makes the melt flow inside the crystallizer more uniform by installing a diverter plate with a six-way diverter tube and an ingot base with a double-stage boss below the guide tube. During the casting process, the flow pattern of the melt has an important influence on the temperature field distribution inside the liquid cavity, thermal cracking, and macro-segregation. When the diverter plate is not added, the melt will form two vortices at the solidification front and the edge of the molten pool under the action of thermal buoyancy and momentum convection. The main flow velocity of the melt is at the solidification front and the upper part of the molten pool, and the distribution is uneven. After adding the traditional diverter plate, due to the action of the diverter plate, the melt generates a strong vortex in the molten pool, and reduces the vertical downward flow velocity of the melt in the center of the molten pool. The melt flow rate distribution is more uniform, and the temperature gradient of the ingot center and surface is reduced to a certain extent. However, when the melt flows through the traditional diverter plate, it is difficult to control the uniformity of the melt flow in the radial direction of the diverter plate. There is still a certain temperature difference in the radial direction of the molten pool, which leads to an increase in stress and then cracks. Compared with the traditional diverter plate, the diverter plate with six-way diverter tubes in the present invention diverts the melt into six diverter tubes when it flows downward and reaches the center of the diverter plate, which significantly shortens the diversion distance of the melt and reduces the unevenness of the melt flow in the radial direction of the diverter plate. It can effectively improve the macro-segregation of the ingot and reduce quality problems such as ingot cracking.

[0072] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A semi-continuous casting device for large-scale high-alloyed magnesium rare earth alloy ingots, characterized in that: It includes a cylindrical crystallizer, a starter base that can be sleeved with the crystallizer, and a diverter plate arranged above the crystallizer for guiding the melt. The starter base can move relative to the crystallizer, wherein: A multi-stage arc boss with a radius that increases from top to bottom is provided on the inner bottom surface of the ingot base, which is used to promote the high-temperature melt to flow to the edge of the molten pool faster and reduce the temperature difference between the core and the edge of the molten pool; the diverter plate includes a vertical pipe and a plurality of fan-shaped diverter areas, and the diverter areas are arranged along the circumference of the vertical pipe. The high-temperature melt flows from the vertical pipe, flows out through the diverter areas, and enters the crystallizer, making the radial flow of the high-temperature melt more uniform; The diversion plate is made of stainless steel, wherein the vertical pipe is threadedly connected to the furnace guide pipe. The high-temperature melt flows out of the furnace and flows into the vertical pipe through the furnace guide pipe. At the same time, in order to prevent the melt from seeping out during the casting process, talcum powder and water glass are used to seal the threaded connection; and in order to improve the connection strength between the vertical pipe and the diversion area, a number of reinforcing ribs are also provided between the vertical pipe and the diversion plate.

2. The semi-continuous casting device for large-scale high-alloyed magnesium rare earth alloy ingots according to claim 1 is characterized in that: The multi-stage circular arc boss is a double-stage circular arc boss, comprising a primary circular arc boss connected to the bottom surface of the starter base, and a secondary circular arc boss on the primary circular arc boss.

3. The semi-continuous casting device for large-scale high-alloyed magnesium rare earth alloy ingots according to claim 1 is characterized in that: The crystallizer includes a crystallizer inner sleeve and a crystallizer outer sleeve. A platform edge is provided along the circumference of the crystallizer inner sleeve. The top of the crystallizer outer shell is provided with an annular platform that cooperates with the platform edge. The annular platform is located below the platform edge. The crystallizer outer shell is also provided with an outer shell connected to the annular platform for embedding the crystallizer inner sleeve.

4. The semi-continuous casting device for large-scale high-alloyed magnesium rare earth alloy ingots according to claim 3 is characterized in that: An annular cooling water trough is provided between the crystallizer shell and the crystallizer inner sleeve. A water inlet pipe is provided on the crystallizer shell, and the water inlet pipe is communicated with the cooling water trough.

5. The semi-continuous casting device for large-scale high-alloyed magnesium rare earth alloy ingots according to claim 4 is characterized in that: The water inlet pipes are arranged on both sides of the crystallizer shell.

6. The semi-continuous casting device for large-scale high-alloyed magnesium rare earth alloy ingots according to claim 3 is characterized in that: Secondary cooling water outlet holes are provided along the lower side of the inner sleeve of the crystallizer. The water outlet holes are arranged obliquely, corresponding to the moving direction of the ingot during semi-continuous casting.

7. The semi-continuous casting device for large-scale high-alloyed magnesium rare earth alloy ingots according to claim 3 is characterized in that: The shape of the inner sleeve of the crystallizer is a trumpet shape that is wide at the top and narrow at the bottom, and the inclination angle is 1-6 degrees.

8. The semi-continuous casting device for large-scale high-alloyed magnesium rare earth alloy ingots according to claim 3 is characterized in that: An oil inlet pipe is provided between the platform edge and the annular platform, an oil groove is provided along the circumference of the annular platform, and an oil lubrication spray hole communicating with the oil groove is provided on the platform edge.

9. The semi-continuous casting device for large-scale high-alloyed magnesium-rare earth alloy ingots according to claim 8, characterized in that: The oil inlet pipelines are arranged on both sides of the inner sleeve of the crystallizer.

10. The semi-continuous casting device for large-scale high-alloyed magnesium rare earth alloy ingots according to claim 1, characterized in that: The number of the diversion areas is six, and the six diversion areas are evenly distributed on the circumference of the vertical pipe.

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