Non-ferrous semi-continuous casting melt homogenization stirring device

Abstract

The application belongs to the field of stirring technology and discloses a non-ferrous metal semi-continuous casting melt homogenizing stirring device, which comprises a support control assembly, a stirring assembly and a flow field control assembly, the support control assembly is fixed on the upper end working platform of the non-ferrous metal semi-continuous casting device, is used for fixing and installing the stirring assembly and the flow field control assembly, the stirring assembly is arranged at the center of a crystallizer, is used for guiding the melt movement in a melt pool, and the flow field control assembly is arranged outside the stirring assembly, is used for restraining the tangential flow in the melt movement process and simultaneously strengthening the axial flow. The application inhibits the formation of harmful tangential flow, avoids the generation of vortex, ensures that the internal temperature field and composition field of the melt are more uniform, and effectively improves the product quality.

Description

Technical Field

[0001] This invention belongs to the field of stirring technology, and particularly relates to a stirring device for homogenizing non-ferrous metal semi-continuous casting melt. Background Technology

[0002] Semi-continuous casting is a primary process for producing large-scale magnesium and aluminum alloys. During semi-continuous casting, due to directional heat dissipation from the melt, temperature gradients exist in different regions of the molten pool. In the subsequent solidification process, the lower-temperature edges solidify first, resulting in finer grains, while the higher-temperature center solidifies last, allowing sufficient time for grain growth. This leads to an uneven grain size distribution across the entire ingot cross-section. Furthermore, in the alloyed melt, denser alloying elements tend to sink, while less dense elements tend to float, resulting in inconsistent chemical composition between the upper and lower layers of the molten pool and severe macroscopic segregation in the produced ingot. Grain refiners or modifiers added to improve material properties also lose their effectiveness because they cannot disperse rapidly and uniformly throughout the molten pool.

[0003] Traditional stirring methods rely on mechanical stirrers, typically consisting of a drive motor, a drive shaft, and a straight-blade or inclined-blade stirrer mounted at the end of the drive shaft. The stirrer is immersed in the melt, and under the action of the drive motor, it rotates at high speed, directly shearing and dragging the melt, thus causing it to move. However, the rotation of the stirrer inevitably induces a strong tangential flow in the melt. This flow pattern is mainly characterized by the melt moving in a circular motion around the stirring shaft, forming a significant vortex effect, which leads to the following problems:

[0004] (1) Most of the stirring energy is wasted on meaningless rotation rather than beneficial radial and axial mixing, and this rotational motion contributes little to the mixing of the melt.

[0005] (2) It leads to high energy consumption and low efficiency, and there is a mixed "dead zone": the flow field dominated by tangential flow leads to weak melt exchange between "layers", resulting in uneven distribution of melt temperature and composition, and ultimately causing macroscopic defects in the ingot structure, such as coarse and uneven grains, and severe segregation of solute elements.

[0006] (3) Violent fluctuations in the liquid surface can easily lead to air entrapment: Violent circumferential rotation causes the edges of the liquid surface to bulge and the center to sink, forming vortices. When the vortex is large enough, it will directly entrain the oxide film and air into the interior of the melt, forming inclusions and pores. Summary of the Invention

[0007] To at least partially solve the technical problems existing in the prior art, the present invention provides a non-ferrous metal semi-continuous casting melt homogenization stirring device.

[0008] The non-ferrous metal semi-continuous casting melt homogenization stirring device of the present invention includes a support and control component, a stirring component, and a flow field control component. The support and control component is fixed on the upper working platform of the non-ferrous metal semi-continuous casting device and is used to fix the stirring component and the flow field control component. The stirring component is located at the center of the crystallizer and is used to guide the movement of the melt within the crystallizer. The flow field control component is located outside the stirring component and is used to constrain the tangential flow during the melt movement while simultaneously enhancing the axial flow, wherein:

[0009] The support control assembly includes a support frame, a connecting rod, and a flange. One end of the connecting rod is fixed to the support frame by bolts, and the other end of the connecting rod is fixed to the flange by bolts.

[0010] The flow field control component includes a flow divider plate and a flow guide tube. The top of the flow divider plate is welded to the central flange of the flange; the top of the flow guide tube is welded to the outer circumference of the flange.

[0011] The stirring assembly includes a drive motor, a transmission shaft, a stirring shaft, and two sets of turbofan blades. The stirring shaft passes through the flow divider and is placed inside the flow guide tube. The stirring shaft is connected to the output end of the drive motor through the transmission shaft to provide rotational power to the stirring shaft. The two sets of turbofan blades are mirror-symmetrically arranged on the stirring shaft.

[0012] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, the diversion plate has a disc-shaped structure, the middle of the diversion plate is provided with an installation hole adapted to the diameter of the stirring shaft, and the diversion plate is uniformly provided with a plurality of diversion holes for dispersing the melt in the circumferential direction, the diameter of the diversion holes being 5mm.

[0013] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, the guide cylinder is a hollow cylindrical structure, and its wall surface is provided with a number of guide holes for guiding the direction of the melt jet. The guide holes are streamlined in shape, with the cross-sectional structure of an aircraft wing, and the thickness at the inlet channel of the guide hole is greater than the thickness at the outlet.

[0014] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, the guide holes are symmetrically distributed with the central axis of the guide cylinder as the axis of symmetry. The guide holes located above the central axis have an upper convex and lower flat structure, while the guide holes located below the central axis have a lower concave and upper flat structure.

[0015] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, the height of the guide tube is adapted to the depth of the molten pool in the crystallizer of the non-ferrous metal semi-continuous casting device, and the depth of the guide tube immersed in the melt is not less than two-thirds of its total height.

[0016] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, in the two sets of turbine blades, the upper turbine blade is used to guide the melt to be injected obliquely downwards, and the lower turbine blade is used to guide the melt to be injected obliquely upwards, and each set of turbine blades has no less than four blades.

[0017] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, the blade angle of each turbofan blade changes continuously along its length direction, and the angle with the horizontal plane transitions from 0° to 60°.

[0018] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, the top of the diversion plate and the guide cylinder are both welded to the flange by circumferential weld.

[0019] The non-ferrous metal semi-continuous casting melt homogenization stirring device of the present invention has the following advantages and beneficial effects:

[0020] This invention ensures that the melt enters the molten pool smoothly and uniformly by setting up a flow divider, providing stable initial conditions for stirring. Through the cooperation of the stirring component and the guide tube, energy utilization is improved, the formation of harmful tangential flow is suppressed, and the generation of vortices is avoided, ensuring that the internal temperature field and composition field of the melt are more uniform, thus effectively improving product quality. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for further understanding of the embodiments of the present invention and constitute a part of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0022] Figure 1 This is a schematic diagram of the non-ferrous metal semi-continuous casting melt homogenization stirring device of the present invention.

[0023] Figure 2 This is a schematic diagram of the turbine blade installation structure of the non-ferrous metal semi-continuous casting melt homogenization stirring device of the present invention.

[0024] Figure 3 This is a schematic diagram of the diversion plate structure of the non-ferrous metal semi-continuous casting melt homogenization stirring device of the present invention.

[0025] Figure 4 This is a schematic diagram of the guide tube structure of the non-ferrous metal semi-continuous casting melt homogenization stirring device of the present invention.

[0026] Figure 5This is a schematic diagram of the guide hole structure on the guide cylinder of the non-ferrous metal semi-continuous casting melt homogenization stirring device of the present invention.

[0027] Figure 6 The product prepared by stirring using the non-ferrous metal semi-continuous casting melt homogenization stirring device of the present invention. Optical microstructure of a 530mm ZK61-1Y magnesium alloy ingot.

[0028] Explanation of reference numerals in the attached figures:

[0029] 100: Crystallizer; 200: Working platform;

[0030] 1: Support control assembly; 11: Support frame; 12: Connecting rod; 13: Flange;

[0031] 2: Stirring assembly; 21: Drive motor; 22: Transmission shaft; 23: Stirring shaft; 24: Turbofan blades;

[0032] 3: Flow field control components;

[0033] 31: Diverter plate; 311: Mounting hole; 312: Diverter hole;

[0034] 32: Flow guide tube; 321: Flow guide hole. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0036] like Figures 1 to 5 As shown, the non-ferrous metal semi-continuous casting melt homogenization stirring device of the present invention includes a support and control component 1, a stirring component 2, and a flow field control component 3. The support and control component 1 is fixed on the upper working platform 200 of the non-ferrous metal semi-continuous casting device and is used to fix and install the stirring component 2 and the flow field control component 3. The stirring component 2 is located at the center of the crystallizer 100 and is used to guide the movement of the melt in the crystallizer. The flow field control component 3 is located outside the stirring component 2 and is used to constrain the tangential flow during the melt movement while strengthening the axial flow.

[0037] The support control assembly 1 includes a support frame 11, a connecting rod 12 and a flange 13. One end of the connecting rod 12 is fixed to the support frame 11 by bolts, and the other end of the connecting rod 12 is fixed to the flange 13 by bolts.

[0038] The flow field control component 3 includes a flow divider 31 and a flow guide tube 32. The top of the flow divider 31 is welded to the middle flange of the flange 13; the top of the flow guide tube 32 is welded to the outer circumference of the flange 13.

[0039] The stirring assembly 2 includes a drive motor 21, a transmission shaft 22, a stirring shaft 23, and two sets of turbofan blades 24. The stirring shaft 23 passes through the diversion plate 31 and is placed inside the guide tube 32. The stirring shaft 23 is connected to the output end of the drive motor 21 through the transmission shaft 22 to provide rotational power to the stirring shaft 23. The two sets of turbofan blades 24 are mirror-symmetrically arranged on the stirring shaft 23.

[0040] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, the diversion plate 31 has a disc-shaped structure. The diversion plate 31 has a mounting hole 311 in the middle that matches the diameter of the stirring shaft 23. The diversion plate 31 has a number of diversion holes 312 for dispersing the melt evenly in the circumferential direction. The diameter of the diversion holes 312 is 5mm. Thus, when the melt enters the crystallizer 100, the diversion plate 31 guides the melt to be evenly distributed to the entire liquid surface of the crystallizer 100, avoiding the phenomenon of liquid surface impact.

[0041] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, the guide cylinder 32 is a hollow cylindrical structure, and its wall surface is provided with a number of guide holes 321 for guiding the direction of the melt jet. The guide holes 321 are streamlined in shape, with the cross-sectional structure of an aircraft wing. The thickness of the inlet channel of the guide hole 321 is greater than the thickness of the outlet, thereby increasing the jet outlet velocity of the guide hole 321, enabling the melt jet to be sprayed to a greater distance, and increasing the melt circulation speed outside the guide cylinder 32.

[0042] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, the guide holes 321 are symmetrically distributed with the central axis of the guide cylinder 32 as the axis of symmetry. The guide holes 321 located above the central axis have an upper convex and lower flat structure, while the guide holes 321 located below the central axis have a lower concave and upper flat structure. This allows the jet generated by the upper guide holes 321 to mainly push the melt to circulate downwards, while the jet generated by the lower guide holes 321 mainly pushes the melt to circulate upwards. The two sets of symmetrically distributed guide holes 321 can effectively drive the axial circulation of the melt outside the guide cylinder 32.

[0043] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, the height of the guide tube 32 is adapted to the depth of the molten pool inside the crystallizer 100 of the non-ferrous metal semi-continuous casting device, and the depth of the guide tube 32 immersed in the melt is not less than two-thirds of its total height.

[0044] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, in the two sets of turbine blades 24, the upper turbine blade 24 is used to guide the melt to be injected obliquely downward, and the lower turbine blade 24 is used to guide the melt to be injected obliquely upward, and each set of turbine blades 24 has no less than four blades.

[0045] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, the blade angle of each turbine blade 24 changes continuously along its length direction, and the angle with the horizontal plane transitions from 0° to 60°, thereby guiding the melt to move in a specific direction and avoiding the impact of the melt on the turbine blade 24, thus improving the service life of the turbine blade 24.

[0046] Furthermore, in the above-mentioned non-ferrous metal semi-continuous casting melt homogenization stirring device, the tops of the diversion plate 31 and the guide cylinder 32 are both welded to the flange 13 by circumferential weld.

[0047] Specifically, during use, the melt is introduced into the distribution plate 31 through the gating system. The distribution plate 31 disperses the melt into several fine streams through the distribution holes 312 on the side wall, allowing it to enter the liquid surface of the crystallizer 100 evenly and smoothly, effectively avoiding the impact of a single stream on the liquid surface. After the melt level reaches the predetermined height, the drive motor 21 is started. The drive motor 21 drives the stirring shaft 23 through the transmission shaft 22, which in turn drives the turbine blades 24 to rotate. At this time, the rotating turbine blades 24 guide the melt to move along a specific trajectory. After the melt is captured by the turbine blades 24, it is guided from the horizontal direction at its inlet to a direction that forms a 60° angle with the horizontal direction and is ejected. That is, the upper turbine blades 24 guide the melt to be ejected obliquely downward, and the lower turbine blades 24 guide the melt to be ejected obliquely upward. This drives the melt to generate a strong axial circulation inside the guide tube 32. During this process, the guide tube 32 plays a constraining role in the movement of the melt, effectively preventing large-scale circulation inside. The tangential flow of the melt impacting the wall of the guide tube 32 allows it to exit the interior of the guide tube 32 through the "airfoil-shaped" guide holes 321 on its wall. This "airfoil-shaped" guide hole 321 structure effectively reduces flow resistance and increases jet exit velocity. The strong and penetrating jet can effectively impact the inner wall of the crystallizer 100. At the same time, the unique asymmetric design determines the jet direction. When the melt flows through the upper guide hole 321, which is convex at the top and flat at the bottom, it tends to adhere to the upper convex curved surface, thus being given a downward deflection angle and generating a downward jet. When the melt flows through the lower guide hole 321, which is concave at the bottom and flat at the top, it tends to adhere to the lower concave curved surface, thus being given an upward deflection angle and generating an upward jet. The directional jets generated by the two sets of asymmetric guide holes 321 work together to ultimately construct a forced axial circulating flow field outside the guide tube 32 that covers the entire area, has high intensity, and has no dead zones.

[0048] like Figure 6As shown, after inspection, the products produced using this device... The overall microstructure of the 530mm ZK61-1Y magnesium alloy ingot is mainly composed of equiaxed crystals, and no obvious dendritic growth structure was observed. The average grain size at the center, R / 2 and edge of the ingot is 160μm, 152μm and 124μm, respectively. After using the stirring system described in this invention, the microstructure of the ingot is relatively uniform.

[0049] In summary, compared with the prior art, the non-ferrous metal semi-continuous casting melt homogenization stirring device of the present invention has the following advantages and beneficial effects:

[0050] This invention ensures that the melt enters the molten pool smoothly and uniformly by setting up a flow divider, providing stable initial conditions for stirring. Through the cooperation of the stirring component and the guide tube, energy utilization is improved, the formation of harmful tangential flow is suppressed, and the generation of vortices is avoided, ensuring that the internal temperature field and composition field of the melt are more uniform, thus effectively improving product quality.

[0051] It should be noted that, unless otherwise expressly specified and limited, the term "connection" or its synonyms should be interpreted broadly in this document. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, expressions such as "first" and "second" are merely used to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Meanwhile, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In addition, the terms "front," "rear," "left," "right," "upper," and "lower" in this document refer to the placement states shown in the accompanying drawings.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A non-ferrous metal semi-continuous casting melt homogenization stirring device, installed inside the crystallizer of a non-ferrous metal semi-continuous casting device, for stirring the melt within the crystallizer, characterized in that... The non-ferrous metal semi-continuous casting melt homogenization stirring device includes a support control component, a stirring component, and a flow field control component. The support control component is fixed on the upper working platform of the non-ferrous metal semi-continuous casting device and is used to fix the stirring component and the flow field control component. The stirring component is located at the center of the molten pool inside the crystallizer and is used to guide the movement of the molten material in the molten pool. The flow field control component is located outside the stirring component and is used to constrain the tangential flow during the movement of the molten material, while simultaneously enhancing the axial flow. The support control assembly includes a support frame, a connecting rod, and a flange. One end of the connecting rod is fixed to the support frame by bolts, and the other end of the connecting rod is fixed to the flange by bolts. The flow field control component includes a flow divider plate and a flow guide tube. The top of the flow divider plate is welded to the central flange of the flange. The top of the flow guide tube is welded to the outer circumference of the flange. Both the top of the flow divider plate and the top of the flow guide tube are welded to the flange by a circumferential weld. The distribution plate has a disc-shaped structure. The distribution plate has a mounting hole in the middle that matches the diameter of the stirring shaft. The distribution plate has several distribution holes evenly distributed around its circumference to disperse the melt. The diameter of the distribution holes is 5mm. When the melt enters the crystallizer, the distribution plate guides the melt to be evenly distributed on the entire surface of the crystallizer, avoiding the phenomenon of liquid surface impact. The guide tube is a hollow cylindrical structure with several guide holes on its wall to guide the direction of the melt jet. The guide holes are streamlined and have the cross-sectional structure of an aircraft wing. The thickness of the inlet channel of the guide hole is greater than that of the outlet, which increases the jet outlet velocity and allows the melt jet to be sprayed to a greater distance, thereby increasing the melt circulation speed outside the guide tube. The guide holes are symmetrically distributed around the central axis of the guide tube. The guide holes above the central axis have a convex upper and flat lower structure, while the guide holes below the central axis have a concave lower and flat upper structure. This allows the jet generated by the upper guide holes to mainly push the melt to circulate downwards, while the jet generated by the lower guide holes mainly pushes the melt to circulate upwards. The two sets of symmetrically distributed guide holes can effectively drive the axial circulation of the melt outside the guide tube. The guide hole structure can effectively reduce flow resistance and increase the jet exit velocity. The strong and penetrating jet can effectively impact the inner wall of the crystallizer. At the same time, the unique asymmetric design determines the jet direction. The directional jets generated by the two sets of asymmetric guide holes work together to ultimately construct a forced axial circulation flow field outside the guide tube that covers the entire area, has high intensity, and has no dead zones. The height of the guide tube is adapted to the depth of the molten pool in the crystallizer of the non-ferrous metal semi-continuous casting device, and the depth of the guide tube immersed in the melt is not less than two-thirds of its total height. The stirring assembly includes a drive motor, a transmission shaft, a stirring shaft, and two sets of turbofan blades. The stirring shaft passes through the flow divider and is placed inside the flow guide tube. The stirring shaft is connected to the output end of the drive motor through the transmission shaft to provide rotational power to the stirring shaft. The two sets of turbofan blades are mirror-symmetrically arranged on the stirring shaft. In the two sets of turbofan blades, the upper turbofan blades are used to guide the melt to be injected obliquely downwards, and the lower turbofan blades are used to guide the melt to be injected obliquely upwards. Each set of turbofan blades shall have no fewer than four blades. The blade angle of each turbofan blade changes continuously along its length, with the angle with the horizontal plane transitioning from 0° to 60°. This guides the melt to move in a specific direction and also avoids the melt impacting the turbofan blade, thus improving the service life of the turbofan blade.

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