Device and method for preparing high-alloying aluminum alloy casting rod through semi-continuous casting

Abstract

The invention belongs to the technical field of semi-continuous casting, and particularly relates to a device and method for preparing a high-alloying aluminum alloy casting rod through semi-continuous casting, and the device for preparing the high-alloying aluminum alloy casting rod through semi-continuous casting comprises a water tank with a flow guide pipe arranged at the top, a crystallizer arranged in the water tank and a cooling structure; the crystallizer is provided with a cylindrical inner cavity, and the top end of the crystallizer is hermetically connected with the outlet end of the flow guide pipe to form an internal channel; the cooling structure is in a rod shape, is vertically suspended in the flow guide pipe, at least partially extends into the crystallizer and is used for cooling melt; a graphite ring is embedded in a cylindrical inner cavity of the crystallizer and used for being communicated with a gas supply system and an oil supply system so that an oil gas film can be formed between the graphite ring and the casting rod. According to the device provided by the invention, the rod-shaped cooling structure is designed and combined with the oil gas film, so that the cast rod obtained by casting has good surface smoothness, the internal structure is uniform and fine, and the macrosegregation is obviously improved.

Description

Technical Field

[0001] The invention belongs to the technical field of semi-continuous casting, and in particular relates to a device and a method for preparing high-alloyed aluminum alloy casting rods by semi-continuous casting. Background Art

[0002] In the casting process of high-alloyed alloy bars, due to the high content of alloying elements, the solidification structure is coarse and uneven and the composition is severely segregated due to the characteristics of sequential solidification and selective crystallization of the alloy during solidification, which will affect the performance of the cast bars; at the same time, the semi-continuous casting process inevitably has the phenomenon of uneven alloy melt temperature.

[0003] In order to solve the above problems, the method of applying physical external fields is usually used to interfere with the solidification process of high-alloyed alloys. The physical external fields mainly include electromagnetic fields, gas disturbances, ultrasonic vibrations, etc. The electromagnetic field is mainly divided into: rotating electromagnetic field, traveling electromagnetic field and the composite field of the two. However, since the electromagnetic field has a very low stirring intensity on the core of the alloy melt, there is a phenomenon of uneven stirring. At the same time, since the electromagnetic field has a more obvious improvement on the macro-segregation in the solidification structure of the cast rod, the effect on grain refinement is weak; and the stirring intensity of the gas disturbance on the alloy melt is low, and a good semi-solid solidification structure cannot be obtained; although the shear strength of ultrasonic vibration is high, it can significantly promote the grain refinement of the solidification structure of the cast rod, but the attenuation of ultrasonic vibration in the alloy melt is very obvious, and there is no significant improvement on the macro-segregation of the solidification structure of the cast rod.

[0004] Therefore, in view of the above shortcomings, the present invention is proposed. Summary of the invention

[0005] The main purpose of the present invention is to propose a device and method for preparing high-alloyed aluminum alloy cast rods by semi-continuous casting. In the device provided by the present invention, a rod-shaped cooling structure is designed and combined with an oil-gas film, so that the cast rods have good surface finish, uniform and fine internal structure, and macro-segregation is significantly improved.

[0006] A first aspect of the present invention provides a device for preparing high-alloyed aluminum alloy cast rods by semi-continuous casting, the device comprising a water tank with a guide tube on the top, a crystallizer arranged in the water tank, and a cooling structure; the crystallizer has a cylindrical inner cavity, and the top end of the crystallizer is sealed and connected to the outlet end of the guide tube to form an internal channel; the cooling structure is rod-shaped and vertically suspended in the guide tube and at least partially extends into the crystallizer, and is used to cool the melt; a graphite ring is embedded in the cylindrical inner cavity of the crystallizer, which is used to connect the air supply system and the oil supply system respectively to form a layer of oil and gas film between the graphite ring and the cast rod.

[0007] In some embodiments of the present invention, the axis of the cooling structure is aligned with the axis of the cylindrical inner cavity of the crystallizer.

[0008] In some embodiments of the present invention, taking the horizontal plane where the bottom of the graphite ring is located as a reference line, the distance between the bottom of the cooling structure and the bottom of the graphite ring is -20 mm to 30 mm.

[0009] In some embodiments of the present invention, the diameter of the cooling structure is 30% to 50% of the inner diameter of the flow guide tube.

[0010] In some embodiments of the present invention, the cooling structure is filled with a cooling medium, and the cooling structure is externally connected to a temperature control device to control the temperature of the cooling medium.

[0011] In some embodiments of the present invention, the cooling structure is connected to the temperature control device through an inlet pipeline and an outlet pipeline respectively, so as to form a circulation cooling of the cooling medium.

[0012] In some embodiments of the present invention, the graphite ring is provided with an air groove connected to the air supply system, and an oil groove connected to the oil supply system.

[0013] In some embodiments of the present invention, the oil groove is arranged at one end of the graphite ring close to the flow guide tube, and the ventilation groove is arranged in the middle of the graphite ring.

[0014] In some embodiments of the present invention, the crystallizer is provided with an air inlet channel to connect the air supply system with the ventilation groove, and an oil inlet channel to connect the oil supply system with the oil groove.

[0015] In some embodiments of the present invention, the apertures of the air inlet channel and the oil inlet channel are independently 1.5 mm to 2.5 mm.

[0016] In some embodiments of the present invention, a cooling water cavity is provided on the crystallizer for cooling the cast rods.

[0017] The second aspect of the present invention provides a method for preparing high-alloy aluminum alloy cast rods by semi-continuous casting, and the method is based on the device for preparing high-alloy aluminum alloy cast rods by semi-continuous casting described in the first aspect; the method comprises: regulating the temperature of the cooling structure to the target temperature; pouring the high-alloy aluminum alloy melt at a preset temperature; the high-alloy aluminum alloy melt flows into the crystallizer and starts casting; when the length of the cast rod is 200mm to 400mm, ventilation and pulse oiling are turned on to form an oil-gas film on the graphite ring; the high-alloy aluminum alloy melt is first initially cooled by the cooling structure to form a large number of crystal nuclei around the cooling structure, and then subsequently cooled by the oil-gas film formed on the graphite ring; when the casting is completed, a high-alloy aluminum alloy cast rod is obtained.

[0018] In some embodiments of the present invention, the temperature of the cooling structure is 200°C to 300°C.

[0019] In some embodiments of the present invention, the casting temperature is controlled at 680°C to 720°C.

[0020] In some embodiments of the present invention, during ventilation, the air pressure is controlled at 0.3 MPa to 0.4 MPa.

[0021] In some embodiments of the present invention, the continuous casting speed is controlled to be 180 mm / min to 250 mm / min.

[0022] In some embodiments of the present invention, the pouring temperature is 720°C to 780°C.

[0023] In some embodiments of the present invention, during the casting process, cooling water is sprayed out from the cooling water cavity to continuously cool the cast rods, and the cooling water flow rate is controlled to be 450 L / min to 550 L / min.

[0024] The present invention designs a rod-shaped cooling structure and suspends it into the crystallizer, and combines it with an oil-gas film to cool the core of the high-alloyed aluminum alloy melt in the molten pool to refine the grain structure and improve the surface quality of the cast rod.

[0025] The setting of the cooling structure in the present invention and its combination with the oil-gas film are not a single functional superposition, and they also have strict requirements on the process parameters. In order to achieve the necessary refinement effect, it is necessary to accurately control the insertion depth, temperature and casting process parameters of the cooling structure, and cooperate with each other to improve the coarse and uneven distribution of the internal grain structure of the cast rod and the surface defects such as cold shut, coarse grain layer, segregation, and casting nodules.

[0026] Among them, after the molten metal enters the liquid guide groove, it first contacts the cooling structure. Utilizing the cooling effect of the cooling structure, a large number of crystal nuclei are first formed around it, avoiding the growth of the core structure of the ingot during solidification and the uneven distribution of the structure due to uneven melt temperature. The surface smoothness of the ingot is then improved by combining with the oil-gas film.

[0027] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only used for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. In the accompanying drawings:

[0029] Figure 1 A schematic diagram of the structure of an apparatus for preparing a high-alloyed aluminum alloy casting rod by semi-continuous casting according to some embodiments of the present invention;

[0030] Figure 2 A schematic diagram of the structure of an apparatus for preparing a high-alloyed aluminum alloy casting rod by semi-continuous casting according to other embodiments of the present invention;

[0031] Figure 3 This is a surface diagram of a cast rod produced by continuous casting in Example 1 of the present invention;

[0032] Figure 4 A surface diagram of a cast rod produced by continuous casting in the prior art;

[0033] Figure 5 The metallographic structure diagram of the cast rod produced by continuous casting in Example 1 of the present invention;

[0034] Figure 6 This is a metallographic structure diagram of a cast rod produced by continuous casting in the prior art.

[0035] Reference numerals

[0036] 100. A device for preparing highly alloyed aluminum alloy casting rods by semi-continuous casting;

[0037] 10. Water tank; 11. Flow guide pipe; 12. Liquid guide groove;

[0038] 20. Crystallizer; 21. Graphite ring; 22. Air inlet channel; 23. Oil inlet channel; 24. Cooling water cavity;

[0039] 30. Cooling structure; 31. Inlet pipeline; 32. Outlet pipeline;

[0040] 40. Temperature control device;

[0041] 50. High alloy aluminum alloy melt; 60. Cast rod. DETAILED DESCRIPTION

[0042] The exemplary embodiments of the present invention will be described in more detail below with reference to specific embodiments. It should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" in the specification and claims of the present invention and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0044] In the description of the embodiments of the present invention, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0045] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0046] In the description of the embodiments of the present invention, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects before and after are in an "or" relationship.

[0047] In the description of the embodiments of the present invention, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0048] In the description of the embodiments of the present invention, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention.

[0049] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral 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 connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0050] Although the current method of applying a physical external field can solve the problems of coarse solidification structure and severe component segregation to a certain extent, there are still some shortcomings.

[0051] The present invention provides an apparatus and method for preparing high-alloyed aluminum alloy cast rods by semi-continuous casting, in order to solve the above problems by physical cooling, specifically by combining a cooling core rod with "oil-gas lubrication", and can significantly improve the internal and surface quality of the high-alloyed alloy cast rods, thereby preparing high-alloyed aluminum alloy cast rods.

[0052] The device 100 for preparing high-alloy aluminum alloy casting rods by semi-continuous casting provided by the present invention is shown in FIG. Figure 1-2 As shown, the device 100 includes a water tank 10 with a guide tube 11 on the top, a crystallizer 20 arranged in the water tank 10, and a cooling structure 30; wherein the crystallizer 20 has a cylindrical inner cavity, and the top end of the crystallizer 20 is sealed and connected to the outlet end of the guide tube 11 to form an internal channel; the cooling structure 30 is rod-shaped and vertically suspended in the guide tube 11 and at least partially extends into the crystallizer 20, and is used to cool the melt; a graphite ring 21 is embedded in the cylindrical inner cavity of the crystallizer 20, which is used to connect the air supply system and the oil supply system respectively to form a layer of oil and gas film between the graphite ring 21 and the casting rod 60.

[0053] In an embodiment of the present invention, by designing a rod-shaped cooling structure and suspending it into the interior of the crystallizer, and combining it with an oil-gas film, the core of the high-alloyed aluminum alloy melt in the molten pool can be cooled to refine the grain structure and improve the surface quality of the cast rod.

[0054] In an embodiment of the present invention, by forming a layer of oil and gas film between the cast rod and the inner wall of the cold zone mold (graphite ring) of the crystallizer, the hard contact between the thin solidified shell formed in the early stage of solidification of the alloy melt and the inner wall of the mold (graphite ring) is transformed into a flexible contact, thereby effectively improving the surface quality of the cast rod.

[0055] Continue to see Figure 1 As shown, the water tank 10 has a receiving cavity inside, and the top and bottom of the water tank 10 are respectively provided with openings, and the guide pipe 11 is embedded in the top opening of the water tank 10, and the outlet end of the guide pipe 11 is located in the receiving cavity; the crystallizer 20 is arranged in the receiving cavity of the water tank 10, and the upper end of the crystallizer 20 is sealedly connected to the outlet end of the guide pipe 11 to form an internal channel, and the lower end of the crystallizer 20 is sealedly connected to the side wall at the bottom opening of the water tank 10. A graphite ring 21 is embedded in the cylindrical inner cavity of the crystallizer 20, and the graphite ring 21 is used to connect the air supply system and the oil supply system respectively to form a layer of oil and gas film between the graphite ring 21 and the casting rod 60. The cooling structure 30 is in the shape of a rod, and is vertically suspended in the guide pipe 11 and at least partially extends into the crystallizer 20. At this time, the cooling structure 30 is suspended inside the ring of the graphite ring 21, and the cooling structure 30 is used to cool the melt.

[0056] In the embodiment of the present invention, the inlet end of the flow guide pipe 11 is connected to a liquid guide groove 12, and the cooling structure passes through the liquid guide groove 12 and extends into the internal channel.

[0057] In the high alloy aluminum alloy continuous casting of the present invention, the setting of the cooling structure 30 can change the microstructure and mechanical properties of the solidifying molten aluminum alloy. In the embodiment of the present invention, the size, position and temperature of the cooling structure 30 can affect the microstructure and mechanical properties of the cast rod, and it can also be understood that in the actual production setting, the size, position and temperature of the cooling structure 30 can be flexibly set according to actual needs.

[0058] In the embodiment of the present invention, the axis of the cooling structure 30 is aligned with the axis of the cylindrical inner cavity of the crystallizer 20 .

[0059] In the embodiment of the present invention, the length of the rod-shaped cooling structure 30 needs to be set according to the accommodation depth of the guide tube 11 and the guide groove 12 to ensure that the cooling structure 30 is immersed in the melt.

[0060] In an embodiment of the present invention, the diameter of the rod-shaped cooling structure 30 is controlled to be 30% to 50% of the inner diameter of the flow guide tube 11 to achieve a better cooling effect. Exemplarily, the diameter of the rod-shaped cooling structure can be 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50% of the inner diameter of the flow guide tube 11, or any value that satisfies the above range.

[0061] In the embodiment of the present invention, the horizontal plane where the bottom of the graphite ring 21 is located is taken as the reference line, which can be understood as the 0 scale line, and the distance between the bottom of the cooling structure 30 and the bottom of the graphite ring 21 is -20 mm to 30 mm.

[0062] See also Figure 1 As shown, the cooling structure 30 extends into the interior of the crystallizer 20 and continues to extend into and out of the bottom of the graphite ring 21. At this time, the distance L1 between the bottom of the cooling structure 30 and the bottom of the graphite ring 21 is in the range of -20mm to 0mm. The distance L1 provided by the present invention can be a value of an interval composed of any two values ​​within the above range, for example, it can be -20mm to -10mm, or it can be -10mm to 0mm, and so on. Exemplarily, the distance L1 can be one of -20mm, -19mm, -18mm, -17mm, -16mm, -15mm, -14mm, -13mm, -12mm, -11mm, -10mm, -9mm, -8mm, -7mm, -6mm, -5mm, -4mm, -3mm, -2mm, -1mm, 0mm or any value that satisfies the above range.

[0063] See also Figure 2 As shown, the cooling structure 30 extends into the interior of the crystallizer 20 but does not extend out of the bottom of the graphite ring 21. At this time, the distance L2 between the bottom of the cooling structure 30 and the bottom of the graphite ring 21 is in the range of 0mm to 30mm. The distance L2 provided by the present invention can be a value of an interval composed of any two values ​​within the above range, for example, it can be 0mm to 10mm, or it can be 10mm to 30mm, and so on. Exemplarily, the distance L2 can be 0mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm or any value that satisfies the above range.

[0064] In the continuous casting process of the high-alloyed aluminum alloy of the present invention, the cooling structure 30 should achieve the effect of grain refinement while ensuring that the molten liquid does not directly solidify on the surface of the cooling structure 30, based on which its temperature is controlled at 200° C. to 300° C. For example, the temperature of the cooling structure 30 can be one of 200° C., 210° C., 220° C., 230° C., 240° C., 250° C., 260° C., 270° C., 280° C., 290° C., 300° C. or any value that satisfies the above range.

[0065] In an embodiment of the present invention, the cooling structure 30 has a storage space inside, which is filled with a cooling medium, and the cooling structure is externally connected to a temperature control device 40 to control the temperature of the cooling medium, thereby achieving temperature control of the cooling structure 30 at a target temperature, such as 200°C to 300°C.

[0066] In an embodiment of the present invention, the cooling medium may be heat transfer oil or an inert gas, such as nitrogen, argon, etc., to meet casting production requirements.

[0067] Continue to see Figure 2 As shown, the cooling structure 30 is provided with an inlet and an outlet connected to its accommodating space, and is connected to the temperature control device 40 through the inlet pipeline 31 and the outlet pipeline 32 respectively, so as to form a circulation cooling of the cooling medium.

[0068] In the embodiment of the present invention, the cooling structure 30 is a cooling core rod filled with cooling medium, and the cooling core rod is connected to the temperature control box through the inlet pipe 31 and the outlet pipe 32 to form a circulation cooling of the cooling medium.

[0069] In the embodiment of the present invention, the temperature control device 40 may be, but is not limited to, a temperature control box, which may control the temperature of the cooling medium to meet the requirement of cooling the melt.

[0070] In an embodiment of the present invention, a ventilation groove connected to the air supply system and an oil passage groove connected to the oil supply system are provided on the graphite ring 21. The ventilation groove and the oil passage groove are provided to drain and temporarily store gas and oil, thereby stably forming a layer of oil and gas film on the inner side of the graphite ring 21.

[0071] Continue to see Figure 2 As shown, the graphite ring 21 is provided with an air groove and an oil groove. The oil groove is arranged at the upper end of the graphite ring 21, that is, at the end close to the guide tube 11; the air groove is arranged in the middle of the graphite ring 21, and the gas and oil enter the graphite ring 21 through the air groove and the oil groove respectively, and form a layer of oil and gas film on the inner side of the graphite ring 21.

[0072] In an embodiment of the present invention, the ventilation groove is opened on the outer wall of the graphite ring 21 along the circumference of the graphite ring 21 , and the outer wall of the graphite ring 21 is a side wall close to the cylindrical inner cavity wall of the crystallizer 20 .

[0073] In the embodiment of the present invention, the oil passage groove is provided on the outer side wall of the graphite ring 21 along the circumference of the graphite ring 21, and the oil passage groove and the ventilation groove are provided independently of each other.

[0074] Continue to see Figure 2 As shown, the crystallizer 20 is provided with an air inlet channel 22 and an oil inlet channel 23 to correspond to the air vent and the oil vent on the graphite ring 21 respectively.

[0075] In the embodiment of the present invention, the crystallizer 20 is provided with an air inlet channel 22 to connect the air supply system with the ventilation groove, and is provided with an oil inlet channel 23 to connect the oil supply system with the oil groove.

[0076] In some embodiments of the present invention, the apertures of the air inlet channel 22 and the oil inlet channel 23 are independently 2±0.5 mm, i.e., 1.5 mm to 2.5 mm. For example, the aperture of the air inlet channel 22 can be one of 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, or any value that satisfies the above range. The aperture of the oil inlet channel 23 can be one of 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, or any value that satisfies the above range.

[0077] Continue to see Figure 2 As shown, the crystallizer 20 is provided with a cooling water cavity 24 and a water spray hole connected to the cooling water cavity 24. During the casting process, cooling water is sprayed out through the cooling water cavity 24 to continuously cool the cast rod, which is also called secondary cooling.

[0078] In the embodiment of the present invention, the water spray hole is arranged below the graphite ring 21. Of course, the specific arrangement position can also be arranged according to actual needs.

[0079] The present invention also provides a method for preparing high-alloyed aluminum alloy cast rods by semi-continuous casting. The key to this method is to improve the defects of the coarse and uneven distribution of the internal grain structure of the cast rods and the cold shut, coarse grain layer, segregation, and casting nodules on the surface by setting a cooling structure and accurately controlling the casting process parameters.

[0080] The method for preparing high-alloyed aluminum alloy cast rods by semi-continuous casting in the present invention is carried out according to the following steps.

[0081] 1) Melting high alloy aluminum alloy melt.

[0082] In an embodiment of the present invention, a preset amount of high-alloyed aluminum alloy ingots is melted in a melting furnace to obtain a high-alloyed aluminum alloy melt.

[0083] In an embodiment of the present invention, the melting temperature is 730° C. to 830° C. For example, the melting temperature may be one of 730° C., 740° C., 750° C., 760° C., 770° C., 780° C., 790° C., 800° C., 810° C., 820° C., 830° C., or any value satisfying the above range.

[0084] In an embodiment of the present invention, a pre-slag treatment is performed on the melt during the melting process.

[0085] 2) Degassing, deslagging and deterioration treatment.

[0086] In an embodiment of the present invention, the melt is transferred to a holding furnace, the holding temperature of the holding furnace is set to 730°C to 800°C, and degassing, deslagging and modification treatment are performed in the holding furnace. Exemplarily, the holding temperature may be one of 730°C, 740°C, 750°C, 760°C, 770°C, 780°C, 790°C, 800°C or any value that satisfies the above range.

[0087] 3) Pouring.

[0088] In an embodiment of the present invention, the melt temperature is controlled at 720° C. to 780° C. for pouring. For example, the pouring temperature may be one of 720° C., 730° C., 740° C., 750° C., 760° C., 770° C., 780° C., or any value satisfying the above range.

[0089] 4) Preheating of cooling structure.

[0090] In an embodiment of the present invention, a cooling structure is placed and preheated before casting is started to reach a target temperature, and a temperature control device is turned on to control the temperature.

[0091] In an embodiment of the present invention, the temperature of the cooling structure is 200° C. to 300° C. Exemplarily, the temperature of the cooling structure can be controlled at one of 200° C., 210° C., 220° C., 230° C., 240° C., 250° C., 260° C., 270° C., 280° C., 290° C., 300° C. or any value satisfying the above range.

[0092] 5) Casting.

[0093] In an embodiment of the present invention, the molten metal flows into the crystallizer through the diverter plate to start casting, and the casting temperature is controlled at 680° C. to 720° C. For example, the casting temperature may be one of 680° C., 690° C., 700° C., 710° C., 720° C., or any value satisfying the above range.

[0094] In an embodiment of the present invention, when the length of the cast rod is between 200 mm and 400 mm, ventilation and pulse oiling are turned on, the air pressure is controlled at 0.4 ± 0.1 MPa, i.e., 0.3 MPa to 0.5 MPa, the continuous casting speed is controlled at 180 mm / min to 250 mm / min, and the cooling water flow rate is controlled at 450 L / min to 550 L / min. Exemplarily, the air pressure can be controlled to be one of 0.3 MPa, 0.4 MPa, 0.5 MPa or any value satisfying the above range value. The continuous casting speed can be controlled to be one of 180 mm / min, 190 mm / min, 200 mm / min, 210 mm / min, 220 mm / min, 230 mm / min, 240 mm / min, 250 mm / min or any value satisfying the above range value. The cooling water flow rate can be controlled to be one of 450L / min, 460L / min, 470L / min, 480L / min, 490L / min, 500L / min, 510L / min, 520L / min, 530L / min, 540L / min, 550L / min or any value that meets the above range.

[0095] In the embodiment of the present invention, due to the setting of the cooling structure 30, the melt is firstly cooled by the cooling structure 30 and a large number of crystal nuclei are formed around the cooling structure, and then subsequently cooled by the oil-gas film formed on the graphite ring 21. The oil-gas film is formed by oil and gas passing through the air inlet channel 22 and the oil inlet channel 23 and evenly sprayed through the micro-channels inside the graphite ring 21, and then continuously cooled under the action of secondary cooling water.

[0096] 6) After the casting is completed, a high-alloyed aluminum alloy cast rod is obtained.

[0097] In the embodiments of the present invention, the setting of the cooling structure and its combination with the oil-gas film are not a single functional superposition, and also have strict requirements on the process parameters. In order to achieve the necessary refinement effect, it is necessary to accurately control the insertion depth, temperature and process parameters of the cooling structure, so as to improve the coarse and uneven distribution of the grain structure inside the cast rod and the surface defects such as cold shut, coarse grain layer, segregation, and casting nodules.

[0098] Among them, after the molten metal enters the liquid guide groove, it first contacts the cooling structure. By utilizing the cooling effect of the cooling structure, a large number of crystal nuclei are first formed around it, avoiding the growth of the core structure of the ingot during the solidification process and the uneven distribution of the structure due to uneven melt temperature, and then the surface smoothness of the ingot is improved through the oil-gas film.

[0099] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments and equipment used in the following examples, etc., can all be purchased on the market or can be obtained by existing methods; the amounts of the experimental reagents, unless otherwise specified, are the amounts of reagents used in conventional experimental operations; the experimental methods, unless otherwise specified, are all conventional methods.

[0100] Example 1

[0101] A semi-continuous casting method for high-alloy aluminum alloy casting rods, the casting method is based on Figure 1 The semi-continuous casting method for preparing high-alloyed aluminum alloy cast bars comprises the following steps:

[0102] 1) Melting a high alloy aluminum alloy ingot in a melting furnace to obtain an aluminum alloy melt at a melting temperature of 800° C. Pre-slag treatment is performed on the melt during the melting process.

[0103] 2) The holding temperature of the holding furnace is set to 780° C., and degassing, deslagging and modification treatment are performed in the holding furnace to obtain a high-alloyed aluminum alloy melt 50.

[0104] 3) The melt temperature is controlled at 750°C for pouring.

[0105] 4) Before the casting is started, the cooling structure 30 is placed and preheated to 250° C., and the temperature control device 40 is turned on to control the temperature.

[0106] 5) The molten metal flows into the crystallizer 20 through the diverter plate and starts casting, and the casting temperature is controlled at 700° C. When the length of the cast rod 60 is 200 mm, ventilation and pulse oiling are turned on, the air pressure is controlled at 0.4 MPa, the continuous casting speed is controlled at 200 mm / min, and the cooling water flow rate is controlled at 500 L / min.

[0107] The melt is first cooled by the cooling structure 30 to form a large number of crystal nuclei around the cooling structure 30, and then cooled by the oil-gas film formed on the graphite ring 21. The oil-gas film is formed by oil and gas passing through the air inlet channel 22 and the oil inlet channel 23 and evenly sprayed through the micro-channels inside the graphite ring 21, and then continuously cooled by cooling water.

[0108] 6) After the casting is completed, a high-alloyed aluminum alloy cast rod 60 is obtained.

[0109] In the embodiment of the present invention, the cast rod 60 obtained by casting in Example 1 and the cast rod obtained by casting using a traditional crystallizer in the prior art are simultaneously subjected to metallographic structure analysis using the same equipment and method.

[0110] Combination Figure 5 and Figure 6 It can be seen that based on the design of the casting device and casting process parameters in the present invention, the refinement of the α-Al branches of the cast rod obtained by continuous casting is significantly improved.

[0111] Combination Figure 3 and Figure 4 It can be seen that the surface finish and surface quality of the cast rods produced by continuous casting using a casting device provided with a cooling structure in the present invention are significantly improved compared to the surface finish and surface quality of the cast rods produced by a traditional casting device.

[0112] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A device for preparing high-alloyed aluminum alloy casting rods by semi-continuous casting, characterized in that: The device comprises a water tank with a guide pipe on the top, a crystallizer arranged in the water tank, and a cooling structure; The crystallizer has a cylindrical inner cavity, and the top end of the crystallizer is sealed and connected to the outlet end of the guide tube to form an internal channel; the cooling structure is in a rod shape and is vertically suspended in the guide tube and at least partially extends into the crystallizer, and is used to cool the melt; A graphite ring is embedded in the cylindrical inner cavity of the crystallizer, which is used to connect the air supply system and the oil supply system respectively to form an oil-gas film between the graphite ring and the casting rod.

2. The device for preparing high-alloyed aluminum alloy cast rods by semi-continuous casting according to claim 1, characterized in that: The axis of the cooling structure is aligned with the axis of the cylindrical inner cavity of the crystallizer; Preferably, taking the horizontal plane where the bottom of the graphite ring is located as the reference line, the distance between the bottom of the cooling structure and the bottom of the graphite ring is -20 mm to 30 mm; Preferably, the diameter of the cooling structure is 30% to 50% of the inner diameter of the flow guide pipe.

3. The device for preparing high-alloyed aluminum alloy cast rods by semi-continuous casting according to claim 1, characterized in that: The cooling structure is filled with cooling medium, and the cooling structure is externally connected to a temperature control device to control the temperature of the cooling medium.

4. The device for preparing high-alloyed aluminum alloy cast rods by semi-continuous casting as claimed in claim 3, characterized in that: The cooling structure is connected to the temperature control device through an inlet pipeline and an outlet pipeline respectively, so as to form a circulation cooling of the cooling medium.

5. The device for preparing high-alloyed aluminum alloy casting rods by semi-continuous casting according to claim 1, characterized in that: The graphite ring is provided with an air groove connected to the air supply system, and an oil groove connected to the oil supply system.

6. The device for preparing high-alloyed aluminum alloy casting rods by semi-continuous casting according to claim 4, characterized in that: The oil groove is arranged at one end of the graphite ring close to the flow guide pipe, and the ventilation groove is arranged in the middle of the graphite ring.

7. The device for preparing high-alloyed aluminum alloy casting rods by semi-continuous casting according to claim 5, characterized in that: The crystallizer is provided with an air inlet channel to connect the air supply system with the ventilation groove, and an oil inlet channel to connect the oil supply system with the oil groove; Preferably, the apertures of the air inlet channel and the oil inlet channel are independently 1.5 mm to 2.5 mm; Preferably, a cooling water cavity is provided on the crystallizer for cooling the cast rods.

8. A method for preparing high-alloyed aluminum alloy cast rods by semi-continuous casting, characterized in that: The method is based on the device for preparing high-alloyed aluminum alloy cast rods by semi-continuous casting according to any one of claims 1 to 7; the method comprises: Regulating the temperature of the cooling structure to a target temperature; pouring a high alloy aluminum alloy melt at a preset temperature; The high-alloyed aluminum alloy melt flows into the crystallizer to start casting; When the length of the casting rod is 200mm-400mm, ventilation and pulse oiling are turned on to form an oil-gas film on the graphite ring; The high-alloyed aluminum alloy melt is firstly cooled by the cooling structure to form a large number of crystal nuclei around the cooling structure, and then subsequently cooled by the oil-gas film formed on the graphite ring; After the casting is completed, a high-alloyed aluminum alloy cast rod is obtained.

9. The method for preparing high-alloyed aluminum alloy cast rods by semi-continuous casting according to claim 8, characterized in that: The temperature of the cooling structure is 200°C to 300°C; Preferably, the casting temperature is controlled at 680°C to 720°C; Preferably, during ventilation, the air pressure is controlled at 0.3MPa to 0.5MPa; Preferably, the continuous casting speed is controlled to be 180 mm / min to 250 mm / min; Preferably, the pouring temperature is 720°C to 780°C.

10. The method for preparing high-alloyed aluminum alloy cast rods by semi-continuous casting according to claim 8, characterized in that: During the casting process, cooling water is sprayed out through the cooling water cavity to continuously cool the cast rods, and the cooling water flow rate is controlled to be 450L / min~550L / min.

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