Directional solidification device for metal melting

Abstract

The utility model relates to a kind of directional solidification devices for metal smelting, including smelting furnace body and be located in the crucible of the furnace body, the crucible outside is equipped with the induction coil for inductive heating, the crucible is split type's bottomless water-cooled copper crucible, its inner side wall is equipped with multistage full-wrapping water circulation cooling structure;The top of the crucible is equipped with the rotary feeding table that can continuously feed into the crucible, bottom is equipped with a condensation casting device that can move up and down, the utility model is through the linkage design of top rotary feeding table and bottom condensation casting device, realizes the synchronous of "melting-feeding-solidification-pulling ingot", overcome the defect that the prior art must interrupt pulling ingot to feed, eliminates feeding downtime, so that single furnace time pulling ingot efficiency improves 30%-50%, and can support the continuous preparation of more than one meter long size bar stock, reduce subsequent splicing processing procedure, significantly shorten production cycle.

Description

Technical Field

[0001] This utility model relates to the field of metal smelting technology, and in particular to a directional solidification device for metal smelting. Background Technology

[0002] Water-cooled crucible melting technology (hereinafter referred to as "cold crucible melting") is an advanced material preparation technology. This technology avoids contamination of the molten pool by the crucible material and eliminates the limitation of the melting temperature by the crucible material, making it particularly suitable for melting reactive metals, refractory metals, high-purity and ultra-pure metals and their alloys. Directional solidification technology is one of the core technologies for preparing high-performance metal and alloy materials (such as high-temperature alloys, titanium alloys, and semiconductor single-crystal materials), which improves material properties by precisely controlling the solidification process. In this technology, the water-cooled copper crucible is the core component, and its performance directly determines the quality and efficiency of material preparation.

[0003] However, existing water-cooled copper crucible directional solidification devices still face the following key technical bottlenecks in practical applications:

[0004] Firstly, the simple water circuit structure used in conventional equipment is prone to uneven cooling, causing the crucible to be subjected to severe thermal shock. This not only causes instability at the solidification interface of the molten material, leading to internal defects in the product, but also easily causes deformation, cracking, or oxidation of the crucible body, resulting in a shorter average service life and increasing production costs and downtime.

[0005] Secondly, the feeding and pulling processes of the existing equipment cannot be coordinated. When the material in the crucible is consumed to a certain extent, the production process must be interrupted to replenish the material. This not only disrupts the continuity of solidification, resulting in defective sections with uneven composition and properties in the prepared bars, but also causes low production efficiency, making it difficult to achieve large-scale continuous preparation of long bars. Utility Model Content

[0006] To address the problems of uneven cooling and production interruptions in existing directional solidification devices, this invention provides a directional solidification device for metal smelting, enabling high-quality, high-efficiency, and long-life continuous production.

[0007] The technical solution is as follows: A directional solidification device for metal smelting includes a smelting furnace body and a crucible disposed within the furnace body. An induction coil for induction heating is provided outside the crucible. The crucible is a segmented, bottomless, water-cooled copper crucible with a multi-segment, fully enclosed water circulation cooling structure on its inner wall. This structure includes an inlet copper pipe connected to an inlet connector via an inlet water jacket, and a return copper pipe connected to a return connector via a return water jacket. The inlet and return copper pipes are arranged in a spiral pattern on the inner wall of the crucible and are tightly fitted thereto. A rotating feeding platform for continuously adding material to the crucible is provided at the top of the crucible, and a vertically movable cooling casting device is provided at the bottom. The cooling casting device includes a crystallizer connected to the bottom opening of the crucible and a pull rod mechanism for driving the crystallizer to pull down the ingot.

[0008] As an improvement to the above solution, the inlet copper pipe and the return copper pipe adopt multiple parallel pipelines and are integrally formed with the crucible body by welding.

[0009] As an improvement to the above solution, the inner wall of the crucible is coated with a copper-chromium alloy coating.

[0010] As an improvement to the above scheme, the internal cavity of the crucible is in the shape of a standard cylinder.

[0011] As an improvement to the above solution, the lever mechanism includes a servo motor and a lead screw driven by the servo motor, with the top of the movable rod of the lead screw fixedly connected to the bottom of the crystallizer.

[0012] As an improvement to the above solution, the rotary feeding platform includes a rotary motor, a rotating shaft, and a lifting rack for carrying molten metal raw materials. The rotary motor is located at the top of the furnace body and is connected to the lifting rack through the rotating shaft. The lifting rack can extend along the top of the furnace body to directly above the crucible.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. This utility model achieves the synchronous operation of "melting-feeding-solidification-casting" through the linkage design of the top rotating feeding platform and the bottom solidification casting device. It overcomes the defect of the prior art that requires interruption of casting to feed material, eliminates the downtime for feeding material, improves the casting efficiency of a single furnace by 30%-50%, and can support the continuous preparation of bars with a length of more than one meter. It also reduces the subsequent splicing and processing steps and significantly shortens the production cycle.

[0015] 2. The multi-segment fully enclosed water circulation cooling structure adopted in this utility model provides an extremely uniform temperature field for the crucible. Combined with the precise pull-down control formed by the crystallizer and the pull rod mechanism, it ensures the stability of the solidification interface and the uniformity of the solidification rate.

[0016] 3. This invention utilizes a uniform cooling effect and a copper-chromium alloy coating on the inner wall of the crucible, which together effectively resist the thermal shock and chemical corrosion of the molten material, extending the service life of the crucible body from the conventional 50-80 heats to 120-150 heats. This not only reduces the frequency of crucible replacement and equipment downtime for maintenance, but also reduces equipment maintenance costs by up to 40%, resulting in significant economic benefits. Attached Figure Description

[0017] Figure 1 This is a side cross-sectional view of the crucible, crystallizer, and pull rod mechanism in this utility model.

[0018] Figure 2 This is a schematic diagram of the cooling water circulation structure of this utility model;

[0019] Figure 3 This is a schematic diagram of the structure of the present invention in its initial melting state;

[0020] Figure 4 This is a schematic diagram of the structure of the present invention in the continuous feeding and pulling state;

[0021] Figure 5 This is a schematic diagram of the structure of the present invention in the completed casting state.

[0022] The meanings of the labels in the attached diagram are as follows: 1. Furnace body, 2. Crucible, 3. Water inlet jacket, 4. Water inlet connector, 5. Water inlet copper pipe, 6. Water return jacket, 7. Water return connector, 8. Water return copper pipe, 9. Water circulation path, 10. Crystallizer, 11. Tie rod mechanism, 110. Servo motor, 111. Lead screw, 12. Rotary motor, 13. Rotating shaft, 14. Lifting material rack, a1. Solid raw material, a2. Molten raw material. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] like Figures 1 to 5 As shown, the present invention provides a directional solidification device for metal smelting, which mainly includes a smelting furnace body 1, a crucible 2, a water cooling system, a feeding system, a cooling casting and pull-down system.

[0025] The furnace body 1 is a sealed vacuum chamber with a vacuum port (not shown in the figure) to draw the furnace to the required vacuum level, creating a pollution-free environment for melting. The furnace body 1 is equipped with an induction coil for induction heating, which surrounds the outside of the crucible 2.

[0026] The crucible system adopts a segmented structure, namely a water-cooled copper crucible 2 divided by multiple axial slits. The crucible 2 has a bottomless design and its internal cavity is a standard cylindrical shape. The inner wall of the crucible 2 is coated with a copper-chromium alloy coating to enhance its thermal shock resistance and corrosion resistance, and significantly extend its service life.

[0027] refer to Figure 1 The water cooling system is integrated into the crucible 2, forming a multi-stage, fully enclosed water circulation cooling structure. Specifically, the system includes an inlet connector 4, an inlet water jacket 3, multiple parallel inlet copper pipes 5, multiple parallel return copper pipes 8, a return water jacket 6, and a return connector 7. The inlet copper pipes 5 and return copper pipes 8 are arranged in a staggered spiral pattern and are welded tightly to the inner wall of the crucible 2 body, forming a 360° fully covered heat exchange surface. Cooling water enters from the inlet connector 4, is pre-uniformed by the inlet water jacket 3, and then distributed to each inlet copper pipe 5. After flowing through the crucible 2 wall and carrying away a large amount of heat, it flows into the return copper pipes 8, is buffered by the return water jacket 6, and finally flows out from the return connector 7. This integrated design ensures the extreme uniformity of the temperature field of the crucible 2, controlling fluctuations within ±5℃.

[0028] This device employs a multi-stage, fully enclosed water circulation cooling structure: its multi-stage water circuit system consists of "inlet connector - inlet water jacket - inlet copper pipe - return copper pipe - return water jacket - return connector". Specifically, the inlet water jacket pre-uniformly distributes the cooling water, preventing direct impact on the crucible body and thus avoiding localized overcooling; the inlet and return copper pipes are arranged in a "spiral staggered" pattern and directly adhere to the inner wall of the crucible body, forming a 360° fully enclosed heat exchange; the return water jacket buffers the return water, preventing temperature fluctuations from affecting cooling stability. This structure overcomes the limitations of conventional single-channel systems, achieving full coverage of the cooling range and uniform temperature field control.

[0029] Furthermore, the inlet and outlet copper pipes are welded together as a single unit, avoiding heat loss due to assembly gaps. The inner wall of the crucible is made of segmented water-cooled copper, which, combined with uniform water cooling, reduces the erosion and thermal shock of the crucible by molten material, extending the crucible's service life. Moreover, the integrated water system structure eliminates assembly gaps, reducing the risk of leakage by 90% and avoiding production accidents and maintenance costs caused by water system failures.

[0030] In another preferred embodiment, the crucible 2 is tapered, making it easier to obtain an ingot through downward crystallization.

[0031] refer to Figure 3The feeding system is a rotary feeding platform installed on the top of the furnace body 1. It includes a rotary motor 12, a rotating shaft 13 and a lifting material rack 14. The rotary motor 12 can drive the entire feeding mechanism to rotate and move the material rack 14 directly above the crucible 2. The lifting material rack 14 can carry the neatly arranged bar material or loose granular material down to add the material into the crucible 2, so as to realize continuous or uninterrupted feeding.

[0032] The solidification casting and pull-down system is located at the bottom of crucible 2, and includes a crystallizer 10 and a pull rod mechanism 11. The crystallizer 10 is nearly sealed to the bottom opening of crucible 2, ensuring that molten material can flow in smoothly and begin to solidify. The pull rod mechanism 11 includes a servo motor 110 and a precision lead screw 111 driven by the motor. The movable rod at the top of the lead screw 111 is fixedly connected to the bottom of the crystallizer 10. By driving the crystallizer 10 downward, the pull rod mechanism 11 can pull the solidified metal out of crucible 2.

[0033] The working process of this utility model is as follows:

[0034] 1. Preparation and Melting Stage: After shutting down furnace body 1, the furnace is evacuated to the predetermined vacuum level through the vacuum port. Solid metal raw material a1 is added to crucible 2 through the lifting rack 14 of the feeding system. The induction coil is activated to perform high-frequency induction heating on the raw material in crucible 2 until it is completely melted into a molten state (a2). At the same time, the water cooling system continues to operate, circulating cooling water to cool crucible 2.

[0035] 2. Casting Start-up Stage: Refer to Figure 3 and 4 The molten material a2 flows downwards under gravity, contacts the upper end of the crystallizer 10, and begins to solidify. At this time, the servo motor 110 of the pull rod mechanism 11 is activated, driving the lead screw 111 to move slowly downwards at a preset stable speed, thereby driving the crystallizer 10 and the solidified ingot to move downwards, starting the casting process. The material in the crucible 2 thus forms an ideal structure with the upper part in a molten state a2 and the lower part in a solidified state.

[0036] 3. Continuous casting and feeding stage: (Refer to...) Figure 4 This is the key to this invention. As the material is pulled down, the liquid level in crucible 2 drops. New raw materials (a1) are added to crucible 2 in a timely manner via the rotary motor 12 of the rotating feeding platform and the lifting material rack 14. The newly added raw materials are rapidly melted in the upper part of the crucible, while the material in the lower part continues to solidify and is pulled down, thus achieving a completely continuous preparation process of "upper melting - lower solidification - continuous pulling down - synchronous feeding".

[0037] 4. Ending stage: such as Figure 5As shown, once all materials have been melted and cast, or once the required ingot length has been reached, heating and pulling are stopped to obtain a complete ingot with a dense structure and excellent performance.

[0038] This invention achieves highly uniform temperature field control through a multi-segment fully enclosed water cooling system, effectively suppressing casting defects; through the linkage of rotary feeding and precision pull-down, it realizes true continuous production, greatly improving efficiency and product quality consistency; through the design of segmented crucibles, integrated water circuits and alloy coating, it greatly extends the service life of the core components of the equipment and reduces maintenance costs.

[0039] In addition, the multi-stage fully enclosed water circuit controls the temperature field fluctuation of the crucible body within ±5℃, which is much lower than the ±20℃ of conventional devices. This effectively suppresses defects such as internal stress, porosity, and inclusions in the material, and significantly improves the mechanical properties of the material (such as the tensile strength of high-temperature alloys). The crystallizer-pull rod linkage design controls the diameter tolerance of the bar stock within ±0.1mm, increasing the product qualification rate from the conventional 75% to over 95%, and greatly reducing the degree of compositional segregation.

[0040] This device supports continuous preparation of long bars over 1m in length without the need for subsequent splicing, reducing processing steps and significantly shortening the production cycle. In addition, this device is not only suitable for conventional high-temperature alloys and titanium alloys, but can also meet the requirements for the preparation of materials with higher requirements for temperature field and solidification rate, such as semiconductor silicon single crystals and rare metals (such as tungsten and molybdenum). Compared with conventional devices, its application range is expanded by more than 50%.

[0041] The embodiments described above are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications, improvements, and substitutions without departing from the inventive concept, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A directional solidification apparatus for metal smelting, comprising a smelting furnace body (1) and a crucible (2) disposed within the furnace body (1), wherein an induction coil for induction heating is disposed outside the crucible (2), characterized in that: The crucible (2) is a split bottomless water-cooled copper crucible with a multi-segment fully enclosed water circulation cooling structure on its inner wall. The structure includes a water inlet copper pipe (5) connected to the water inlet connector (4) through the water inlet jacket (3) and a water return copper pipe (8) connected to the water return connector (7) through the water return jacket (6). The water inlet copper pipe (5) and the water return copper pipe (8) are arranged in a spiral staggered pattern on the inner wall of the crucible (2) and are tightly fitted to it. The crucible (2) is provided with a rotating feeding platform at the top for continuous feeding into the crucible, and a cooling casting device that can move up and down at the bottom. The cooling casting device includes a crystallizer (10) connected to the bottom opening of the crucible (2) and a pull rod mechanism (11) for driving the crystallizer (10) to pull down the ingot.

2. The directional solidification apparatus for melting metals according to claim 1, characterized by: The inlet copper pipe (5) and the return copper pipe (8) are multiple parallel pipelines and are integrally formed with the crucible (2) body by welding.

3. The directional solidification apparatus for metal smelting according to claim 1, characterized in that: The inner wall of the crucible (2) is coated with a copper-chromium alloy coating.

4. The directional solidification apparatus for metal smelting according to claim 1, characterized in that: The internal cavity of the crucible (2) is a standard cylindrical shape.

5. The directional solidification apparatus for metal smelting according to claim 1, characterized in that: The lever mechanism (11) includes a servo motor (110) and a lead screw (111) driven by the servo motor (110), with the top of the movable rod of the lead screw (111) fixedly connected to the bottom of the crystallizer (10).

6. The directional solidification apparatus for metal smelting according to claim 1, characterized in that: The rotating feeding platform includes a rotary motor (12), a rotating shaft (13), and a lifting rack (14) for carrying molten metal raw materials. The rotary motor (12) is located at the top of the furnace body (1) and is connected to the lifting rack (14) through the rotating shaft (13). The lifting rack (14) can extend along the top of the furnace body (1) to directly above the crucible (2).

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