Continuous casting device and continuous casting method for composite steel billet

Abstract

The invention relates to the field of continuous casting, in particular to a composite steel billet continuous casting device and method. The composite steel billet continuous casting device comprises a bearing frame, a crystallizer, a cooling system, a width dynamic adjusting mechanism and the like, a physical separator is arranged in the crystallizer to separate a flow channel, the cooling system can independently control the cooling strength of the flow channel, and the width dynamic adjusting mechanism can adjust the width ratio of the flow channel; the invention further comprises a continuous casting method applying the device, different molten steel is injected into the independent runners, and metallurgical bonding is achieved by controlling cooling to enable the molten steel to meet in a solid-liquid state. The technical effects that the cooling strength of all the flow channels can be independently controlled, the width ratio of the flow channels is adjusted to control growth of the solidified billet shell, and metallurgical bonding of the two kinds of molten steel is achieved in the solid-liquid state to form the composite billet with the gradient transition interface are achieved.

Description

Technical Field

[0001] This application relates to the technical field of continuous casting, and in particular to a composite billet continuous casting apparatus and method. Background Technology

[0002] High-performance composite steels (such as stainless steel / carbon steel and high-strength steel / plain carbon steel composite billets) can combine multiple performance advantages (such as corrosion resistance and strength, wear resistance and toughness), and have broad application prospects in energy and chemical industries, transportation, and high-end equipment manufacturing. As these fields continue to demand higher material performance, the market demand for high-performance composite steels is growing, and their development is of great significance for promoting technological progress and product upgrades in related industries.

[0003] Currently, in the field of metal processing and continuous casting technology, solid-state composite methods such as rolling composite and explosive composite are commonly used to produce high-performance composite steel. Rolling composite combines different metal materials by rolling, achieving metal composite to a certain extent, but requires multiple rolling processes, making the production process relatively lengthy. Explosive composite uses the energy generated by an explosive detonation to combine two metal materials; this method has high requirements for equipment and operating environment, and is relatively expensive. In addition, the industry has proposed electromagnetic side-sealing composite technology, which attempts to control the flow and solidification of molten steel using electromagnetic force.

[0004] However, these technologies have many drawbacks. Solid-state bonding methods such as rolling bonding and explosive bonding suffer from lengthy production processes and high energy consumption. Furthermore, the interfaces are prone to oxidation or contamination during the bonding process, leading to insufficient bonding strength and high costs, making it difficult to meet the demands of large-scale, low-cost, and high-quality production. Electromagnetic side-sealing technology is complex to control, consumes enormous amounts of energy, and is sensitive to the physical properties of molten steel, making its practical application difficult. Therefore, existing technologies lack a core method and equipment that can fundamentally solve the problem of achieving controllable solidification and metallurgical bonding between two molten metals. Summary of the Invention

[0005] To address the technical challenges of long preparation processes, high energy consumption, and difficulty in controlling interface quality in traditional composite materials, this application provides a composite billet continuous casting apparatus and method.

[0006] In a first aspect, this application provides a composite billet continuous casting apparatus, employing the following technical solution: a composite billet continuous casting apparatus, comprising a load-bearing frame; a crystallizer connected to the load-bearing frame, the crystallizer having a rectangular vertical cross-section, a physical separator within the crystallizer dividing the cavity near the upper part of the crystallizer into a first flow channel and a second flow channel along the length direction, the ends of the first flow channel and the second flow channel converging to form a combined flow channel near the lower part of the cavity of the crystallizer; a cooling system, comprising a first flow channel cooling system and a second flow channel cooling system corresponding to the first flow channel and the second flow channel respectively, the first flow channel cooling system and the second flow channel cooling system being used to independently control the cooling intensity of the corresponding flow channels; and a width dynamic adjustment mechanism, the width dynamic adjustment mechanism being used to drive the physical separator to reciprocate along the length direction of the crystallizer to adjust the width ratio of the first flow channel and the second flow channel to control the growth of the solidified billet shell.

[0007] By adopting the above technical solution, the load-bearing frame provides support for the crystallizer. The physical separator inside the crystallizer with a rectangular vertical cross section divides the cavity into a first flow channel and a second flow channel, which converge at the bottom to form a combined flow channel, allowing the two types of molten steel to flow separately and eventually combine. Two independent cooling systems can independently adjust the cooling intensity of the two flow channels, achieving independent and precise control over the solidification behavior of the molten steel on both sides. The width dynamic adjustment mechanism can adjust the width ratio of the two flow channels, control the growth of the solidified billet shell, and ensure the stability of the "solid-liquid" composite interface. This enables the production of high-performance composite steel billets with excellent interfacial metallurgical bonding quality in a short process, with high efficiency and low cost.

[0008] Optionally, the physical separator includes a dividing section and a converging section. The dividing section is a straight-extending structure, and the converging section is an inwardly converging structure. The physical separator includes a first water-cooled plate and a second water-cooled plate arranged symmetrically. Both the first water-cooled plate and the second water-cooled plate include a straight section arranged in a vertical direction and a bent section located at the bottom of the straight section. The two straight sections constitute the dividing section, and the two bent sections constitute the converging section. In the crystallizer, the side of the first water-cooled plate away from the second water-cooled plate is the first flow channel.

[0009] By adopting the above technical solution, the dividing part of the physical separator separates the molten steel in the crystallizer, allowing the molten steel to enter two flow channels respectively; the inward converging structure of the confluence part helps the two types of molten steel to merge at the end; the water-cooling plate can cool the molten steel, and together with the cooling system, it can control the solidification process of the molten steel, laying the foundation for the subsequent formation of high-quality composite steel billets.

[0010] Optionally, a copper plate is provided on the side of the first water-cooled plate and the second water-cooled plate that are far apart from each other, and a high-density corundum is provided at the bottom of the confluence portion, and the first water-cooled plate and the second water-cooled plate are fixedly connected by the high-density corundum.

[0011] By adopting the above technical solution, a copper plate is set on the side of the first water-cooled plate and the second water-cooled plate that are far apart from each other, which can improve cooling efficiency and heat conduction performance. A high-density corundum is set at the bottom of the confluence and used to fix and connect the first water-cooled plate and the second water-cooled plate, which can ensure the stability of the separator structure, optimize the fluid dynamics and thermodynamic performance, and ensure long-term stable operation. This will help to produce high-performance composite steel billets with excellent interfacial metallurgical bonding quality in a short process, with high efficiency and low cost.

[0012] Optionally, the crystallizer adopts a modular assembly structure. The crystallizer includes a first flow channel module and a second flow channel module that can be replaced independently. The vertical cross-sectional shape of the first flow channel module and the second flow channel module is C-shaped. The first flow channel module and the second flow channel module are symmetrically arranged along the length direction of the crystallizer. The first flow channel module and the second flow channel module have a cavity structure. The first flow channel module has a first side cavity inside, and the second flow channel module has a second side cavity inside. The vertical cross-sectional shape of the first side cavity and the second side cavity is C-shaped.

[0013] By adopting the above technical solution, the crystallizer adopts a modular assembly structure, which includes a first flow channel module and a second flow channel module that can be replaced independently, which facilitates the maintenance and component replacement of the crystallizer; the first flow channel module and the second flow channel module are symmetrically arranged and have a cavity structure, which creates conditions for the design of the cooling flow channel.

[0014] Optionally, the first side cavity, the second side cavity, the first straight water-cooled plate, and the second straight water-cooled plate are all filled with heat exchange medium.

[0015] By adopting the above technical solution, the cooling efficiency of each component can be improved by utilizing the heat exchange medium, the solidification process of molten steel can be controlled more effectively, the stability of the "solid-liquid" composite interface position can be ensured, and the interfacial metallurgical bonding quality of the composite steel billet can be improved.

[0016] Optionally, the first flow channel cooling system includes a first parallel fixed cooling water channel disposed in the first side cavity, a first parallel linkage cooling water channel disposed in the first straight water-cooled plate, and a first flow control component for controlling the flow rate in the first parallel fixed cooling water channel and the first parallel linkage cooling water channel; the second flow channel cooling system includes a second parallel fixed cooling water channel disposed in the second side cavity, a second parallel linkage cooling water channel disposed in the second straight water-cooled plate, and a second flow control component for controlling the flow rate in the second parallel fixed cooling water channel and the second parallel linkage cooling water channel.

[0017] By adopting the above technical solution, the flow rates in the first parallel fixed cooling channel, the first parallel linked cooling channel, the second parallel fixed cooling channel, and the second parallel linked cooling channel are independently controlled by the first and second flow control components, respectively. This achieves independent control of the cooling intensity of the first and second channels, and precisely regulates the solidification process of the molten steel on both sides. The key is to ensure that the solidification fronts of the two types of molten steel reach an ideal "solid-liquid" composite state at the end of the physical separator, that is, one side forms a solidified billet shell (solid phase) of sufficient thickness and reliable strength, while the other side remains mainly liquid or forms only an extremely thin billet shell (liquid phase). During continuous billet drawing, the solid billet shell meets the adjacent liquid metal, and under the combined action of the crystallizer shape and the static pressure of the molten steel, a strong metallurgical bond is achieved, ultimately forming a composite billet with a gradient transition in composition.

[0018] Optionally, the width dynamic adjustment mechanism includes a servo hollow motor, a ball screw, and a nut. The servo hollow motor is connected to the load-bearing frame and is driven by the nut to drive it to rotate around its own axis. The nut is threadedly connected to the ball screw. The ball screw is arranged horizontally and parallel to the length direction of the crystallizer. Both ends of the ball screw are fixedly connected to the first water-cooled plate and the second water-cooled plate, respectively.

[0019] By adopting the above technical solution, a servo hollow motor drives the nut to rotate around its own axis. Because the nut is threadedly engaged with a ball screw, and the ball screw is horizontally positioned parallel to the length of the crystallizer, with its two ends fixed to the first and second water-cooling plates respectively, the ball screw drives the first and second water-cooling plates to move along the length of the crystallizer, thereby adjusting the width ratio of the first and second flow channels. This adjustment process can compensate for thermal deformation, actively control the billet shell growth thickness, ensure the stability of the solid-liquid composite interface, and improve the quality and efficiency of composite billet continuous casting.

[0020] Optionally, the system further includes a control system, which comprises a processor, a temperature sensor group, and a position sensor. The temperature sensor group includes multiple sensors, which are respectively disposed in the first side cavity, the inner cavity of the first water-cooled plate, the second side cavity, and the inner cavity of the second water-cooled plate. The position sensor is disposed in the crystallizer and located between the first water-cooled plate and the second water-cooled plate. The position sensor is fixedly connected to the load-bearing frame. The processor is signal-connected to the temperature sensor group, the position sensor, the first flow control component, the second flow control component, and the servo hollow motor. The processor is used to receive signals from the temperature sensor group and the position sensor, and to issue control commands to the first flow control component, the second flow control component, and the servo hollow motor.

[0021] By adopting the above technical solution, the temperature sensor group in the control system can monitor the temperature of the first side cavity, the inner cavity of the first water-cooled plate, the second side cavity, and the inner cavity of the second water-cooled plate in real time. The position sensor can obtain its own position information relative to the first and second water-cooled plates, and thus obtain the width information of the first and second flow channels. After receiving these signals, the processor can issue control commands to the first flow control component, the second flow control component, and the servo hollow motor according to the temperature and position conditions, accurately adjust the cooling intensity of the first and second flow channels, and precisely control the flow channel width ratio. This ensures that the solidification process of the two molten steels is precisely controlled, so that the two molten steels reach an ideal "solid-liquid" composite state at the end of the physical separator, improve the interfacial metallurgical bonding quality and product consistency of the composite steel billet, and enhance the stability and reliability of the device operation.

[0022] Secondly, this application provides a continuous casting method for composite steel billets, applied to the composite steel billet continuous casting apparatus described above, comprising the following steps: The first type of molten steel and the second type of molten steel are injected into two separate flow channels respectively; By independently controlling the cooling intensity of each flow channel, each type of molten steel undergoes initial solidification within its respective flow channel, forming a preliminary solidified shell. The solidification process of the two types of molten steel is controlled so that at the end of the physical separator, the first type of molten steel is in a solid or semi-solid state, while the second type of molten steel remains in a liquid or semi-solid state, so that the two meet in a "solid-liquid" state. During continuous billet drawing, the two metals in "solid-liquid" states meet and achieve metallurgical bonding under pressure, forming a composite billet with a gradient transition interface.

[0023] By adopting the above technical solution, the first and second types of molten steel are injected into two independent flow channels, allowing for the separate delivery of steels with different compositions. Independent control of the cooling intensity of each flow channel enables precise regulation of the initial solidification of the molten steel, forming a preliminary solidified shell and creating conditions for solid-liquid composite formation. Controlling the solidification process avoids severe miscibility at the interface, transforming the control of "liquid-liquid miscibility" into stable "solid-liquid composite formation," allowing the molten steel to meet in a "solid-liquid" state at the end of the physical separator, improving interface quality. During continuous casting, the two metals in the "solid-liquid" state metallurgically combine under pressure, forming a composite billet with a gradient transition interface. This simplifies multi-pass rolling or explosive composite processes into a single continuous casting step, shortening the process and reducing energy consumption and costs. This continuous casting method achieves multi-parameter, high-precision collaborative control of the solidification process, improving product consistency and yield, and the modular design of the equipment ensures long-term stable operation under extreme high-temperature environments.

[0024] Optionally, the casting superheat of the first and second molten steels is in the low-temperature range of 10-20℃, and the casting speed and cooling intensity are controlled in a coordinated manner to ensure that the solidification fronts of the two meet at the same position.

[0025] By adopting the above technical solution, the superheat of the first and second types of molten steel is controlled within a low-temperature range of 10-20℃, which reduces the superheat energy of the molten steel, accelerates the speed at which the molten steel enters the solidification stage, and improves continuous casting efficiency. Simultaneously, the coordinated control of casting speed and cooling intensity ensures that the solidification fronts of the two types of molten steel converge at the same location. When the solidification fronts of the two types of molten steel converge as expected, the semi-solid region of the first solidified metal can serve as a non-uniform nucleation substrate for the later solidified metal, refining the grains and forming a dense transition layer at the interface. Composite plates prepared using this method exhibit a clear elemental diffusion gradient at the interface, forming microstructures such as a pearlitic transition layer and a composite layer, achieving a strong metallurgical bond rather than a simple mechanical adhesion.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. It avoids the uncontrollability of liquid-liquid miscibility, improves interface quality, and can obtain a high-quality interface with controllable structure and properties; 2. Simplify the production process by reducing complex multi-pass rolling or explosive composite processes into one-step continuous casting, thereby reducing energy consumption and costs and meeting the needs of large-scale, low-cost, and high-quality production. 3. It can achieve multi-parameter, high-precision collaborative control of the solidification process, ensuring product consistency and pass rate. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the composite billet continuous casting device provided in the embodiments of this application.

[0028] Figure 2 This is a schematic diagram of the internal structure of the composite billet continuous casting device provided in the embodiments of this application.

[0029] Explanation of reference numerals in the attached drawings: 1-Load-bearing frame; 2-Crystallizer; 201-First flow channel module; 2011-First side cavity; 202-Second flow channel module; 2021-Second side cavity; 3-Cooling system; 301-First parallel fixed cooling water channel; 302-First parallel linkage cooling water channel; 303-Second parallel fixed cooling water channel; 304-Second parallel linkage cooling water channel; 4-Physical separator; 401-First water-cooled plate; 402-Second water-cooled plate; 403-Copper plate; 404-High-density corundum; 5-Servo hollow motor; 6-Ball screw. Detailed Implementation

[0030] The following is in conjunction with the appendix Figure 1-2 This application will be described in further detail.

[0031] This application discloses a composite billet continuous casting apparatus.

[0032] like Figure 1 As shown, the composite billet continuous casting device includes a load-bearing frame 1, a crystallizer 2, a cooling system 3, and a width dynamic adjustment mechanism. The load-bearing frame 1 provides support for the entire device and lays the foundation for the vibration process. The crystallizer 2 is connected to the load-bearing frame 1 and is used to contain molten steel and allow it to initially solidify. The cooling system 3 can independently control the cooling intensity of the corresponding flow channel. The width dynamic adjustment mechanism can drive the physical separator 4 to move to adjust the flow channel width ratio, thereby controlling the growth of the solidified billet shell. This achieves precise control of key parameters during the composite billet continuous casting process and ensures the quality of the composite billet.

[0033] Specifically, the load-bearing frame 1 is the basic supporting component of the entire device, possessing a stable structure and strong load-bearing capacity. The shape and size of the load-bearing frame 1 can be designed according to the size of the crystallizer 2 and the layout of the entire device. Its main function is to provide a stable mounting platform for the crystallizer 2, cooling system 3, and width dynamic adjustment mechanism, etc.

[0034] The crystallizer 2 has a rectangular vertical cross-section and contains a physical separator 4. The physical separator 4 includes a dividing section and a converging section. The dividing section is a straight-line extending structure, and the converging section is an inwardly converging structure. The physical separator 4 consists of a symmetrically arranged first water-cooled plate 401 and a second water-cooled plate 402. Both the first water-cooled plate 401 and the second water-cooled plate 402 include a straight section arranged vertically and a bent section located at the bottom of the straight section. The two straight sections constitute the dividing section, and the two bent sections constitute the converging section. The side of the first water-cooled plate 401 away from the second water-cooled plate 402 in the crystallizer 2 is the first flow channel. A copper plate 403 is provided on the side of the first water-cooled plate 401 and the second water-cooled plate 402 that is away from each other. The copper plate 403 has good thermal conductivity and can quickly transfer the heat of the molten steel, promoting the solidification of the molten steel. The bottom of the confluence section is provided with high-density corundum 404. The first water-cooled plate 401 and the second water-cooled plate 402 are fixedly connected by high-density corundum 404. High-density corundum 404 has the characteristics of high temperature resistance and high strength, which can ensure the stability and reliability of the physical separator 4 in high temperature environment.

[0035] The crystallizer 2 adopts a modular assembly structure, including an independently replaceable first flow channel module 201 and a second flow channel module 202. Both the first flow channel module 201 and the second flow channel module 202 have a C-shaped vertical cross-section and are symmetrically arranged along the length of the crystallizer 2. The first flow channel module 201 and the second flow channel module 202 have a cavity structure. The first flow channel module 201 has a first side cavity 2011, and the second flow channel module 202 has a second side cavity 2021. Both the first side cavity 2011 and the second side cavity 2021 have a C-shaped vertical cross-section. This modular design makes the maintenance, replacement, and upgrading of the crystallizer 2 more convenient. When a module malfunctions or needs improvement, it can be replaced individually without replacing the entire crystallizer 2.

[0036] The first side cavity 2011, the second side cavity 2021, the first straight water-cooled plate, and the second straight water-cooled plate are all filled with heat exchange medium, which can be water or other liquids with good thermal conductivity. The function of the heat exchange medium is to absorb heat from the molten steel and carry it away through circulation, thereby achieving cooling of the molten steel.

[0037] The cooling system 3 includes a first flow channel cooling system 3 and a second flow channel cooling system 3, respectively corresponding to the first and second flow channels. The first flow channel cooling system 3 includes a first parallel fixed cooling water channel 301 disposed in the first side cavity 2011, a first parallel linkage cooling water channel 302 disposed in the first straight water-cooled plate, and a first flow control component for controlling the flow rate in the first parallel fixed cooling water channel 301 and the first parallel linkage cooling water channel 302. The second flow channel cooling system 3 includes a second parallel fixed cooling water channel 303 disposed in the second side cavity 2021, a second parallel linkage cooling water channel 304 disposed in the second straight water-cooled plate, and a second flow control component for controlling the flow rate in the second parallel fixed cooling water channel 303 and the second parallel linkage cooling water channel 304. Through the first flow control component and the second flow control component, the cooling intensity of each flow channel can be independently adjusted, thereby precisely controlling the solidification process of the molten steel on both sides.

[0038] The width dynamic adjustment mechanism includes a servo hollow motor 5, a ball screw 6, and a nut. The servo hollow motor 5 is connected to the load-bearing frame 1 and is driven by the nut to rotate around its own axis. The nut and the ball screw 6 are threadedly connected. The ball screw 6 is horizontally positioned and parallel to the length of the crystallizer 2. Both ends of the ball screw 6 are fixedly connected to the first water-cooled plate 401 and the second water-cooled plate 402, respectively. When the servo hollow motor 5 rotates, the rotational motion of the motor is converted into linear motion of the ball screw 6 through the cooperation of the nut and the ball screw 6, thereby driving the physical separator 4 to reciprocate along the length of the crystallizer 2, thus adjusting the width ratio of the flow channel.

[0039] In addition, the device includes a control system, which comprises a processor, a temperature sensor group, and a position sensor. The temperature sensor group includes multiple sensors located in the first side cavity 2011, the inner cavity of the first water-cooled plate 401, the second side cavity 2021, and the inner cavity of the second water-cooled plate 402, respectively, for real-time monitoring of the temperature at each location. The position sensor is located in the crystallizer 2 between the first water-cooled plate 401 and the second water-cooled plate 402, and is fixedly connected to the load-bearing frame 1, for monitoring the position of the physical separator 4. The processor is signal-connected to the temperature sensor group, the position sensor, the first flow control component, the second flow control component, and the servo hollow motor 5. The processor receives signals from the temperature sensor group and the position sensor, and issues control commands to the first flow control component, the second flow control component, and the servo hollow motor 5 based on these signals, thereby achieving intelligent control of the entire continuous casting process.

[0040] The implementation principle of the composite billet continuous casting device provided in this application embodiment is as follows: the composite billet continuous casting device provides stable support through the load-bearing frame 1, the crystallizer 2 initially solidifies the molten steel, the cooling system 3 independently controls the cooling intensity of the flow channel, the width dynamic adjustment mechanism adjusts the flow channel width ratio, and the control system performs intelligent control based on real-time monitored temperature and position signals. This integrated design enables the device to transform the complex "liquid-liquid miscibility" control into a stable "solid-liquid composite" process, producing high-performance composite billets with excellent interfacial metallurgical bonding quality in a short process, with high efficiency and low cost. It solves the problems of lengthy production process, high energy consumption, and insufficient interfacial bonding strength in the prior art, and has made significant improvements and contributions to the prior art.

[0041] This application also discloses a continuous casting method for composite steel billets, comprising the following steps: S1, the first and second types of molten steel are injected into two separate flow channels. First, it must be ensured that the quality and temperature of the molten steel meet the requirements. The first and second types of molten steel can be injected into the first and second flow channels of the crystallizer 2 from different ladles. During the injection process, the flow rate and volume of the molten steel must be controlled to avoid overflow or large fluctuations. A tundish can be used to buffer the flow of the molten steel and improve the stability of the injection.

[0042] S2, by independently controlling the cooling intensity of each flow channel, allows each type of molten steel to initially solidify within its respective flow channel, forming a preliminary solidified shell. Utilizing the first and second flow channel cooling systems 3 within the cooling system 3, the flow rates in the first parallel fixed cooling channel 301, the first parallel linked cooling channel 302, the second parallel fixed cooling channel 303, and the second parallel linked cooling channel 304 are adjusted by the first and second flow control components, respectively, thereby independently controlling the cooling intensity of each flow channel. Based on the composition, temperature, and continuous casting process requirements of the molten steel, the cooling water volume, pressure, and temperature are precisely adjusted, allowing the molten steel to gradually solidify within the flow channels to form a shell.

[0043] S3 controls the solidification process of the two types of molten steel, ensuring that at the end of the physical separator 4, the first type of molten steel is in a solid or semi-solid state, while the second type remains in a liquid or semi-solid state, thus allowing them to meet in a "solid-liquid" state. This requires precise control of the cooling system 3 and the width dynamic adjustment mechanism by the control system's processor, based on the temperature signals from various parts monitored in real time by the temperature sensor group. If the solidification rate of the first type of molten steel is too fast, the cooling intensity of the first flow channel can be appropriately reduced; if the solidification rate of the second type of molten steel is too slow, the cooling intensity of the second flow channel can be increased. Simultaneously, the width ratio of the flow channels is adjusted by the width dynamic adjustment mechanism to control the growth thickness of the solidified shell, ensuring the stability of the "solid-liquid" composite interface position.

[0044] S4. During continuous billet drawing, the two metals in their solid-liquid states meet and achieve metallurgical bonding under pressure, forming a composite billet with a gradient transition interface. The drawing mechanism continuously pulls the billet shell at a certain speed, enabling the two metals in their solid-liquid states to achieve a strong metallurgical bond under the combined action of the shape of the crystallizer 2 and the static pressure of the molten steel. During the drawing process, the drawing speed and cooling intensity must be controlled in a coordinated manner. The superheat of the first and second types of molten steel is controlled within a low-temperature range of 10-20℃ to ensure that the solidification fronts of the two meet at the same position, thus guaranteeing the quality of the composite billet.

[0045] The implementation principle of the continuous casting method for composite steel billets disclosed in this application is as follows: The continuous casting method transforms the complex "liquid-liquid miscibility" control into a stable "solid-liquid composite" process. By precisely controlling parameters such as the injection of molten steel, cooling intensity, solidification process, and billet pulling speed, controllable solidification and metallurgical bonding of the two types of molten steel are achieved within the crystallizer 2. The resulting composite steel billet has a gradient transition interface with excellent interfacial metallurgical bonding quality. This method avoids the problems of lengthy production processes, high energy consumption, and insufficient interfacial bonding strength in traditional methods, thereby improving production efficiency, reducing costs, and making a significant improvement and contribution to existing composite steel billet continuous casting methods.

[0046] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A composite billet continuous casting device, characterized in that, include: Load-bearing frame (1); Crystallizer (2), the crystallizer (2) is connected to the load-bearing frame (1), the vertical cross-section of the crystallizer (2) is rectangular, the crystallizer (2) is provided with a physical separator (4) to divide the cavity of the crystallizer (2) near the upper part into a first flow channel and a second flow channel along the length direction, the ends of the first flow channel and the second flow channel merge into a combined flow channel near the lower part of the cavity of the crystallizer (2); Cooling system (3), the cooling system (3) includes a first flow channel cooling system (3) and a second flow channel cooling system (3) corresponding to the first flow channel and the second flow channel respectively, the first flow channel cooling system (3) and the second flow channel cooling system (3) are used to independently control the cooling intensity of the corresponding flow channels; A width dynamic adjustment mechanism is used to drive the physical separator (4) to reciprocate along the length direction of the crystallizer (2) to adjust the width ratio of the first flow channel and the second flow channel to control the growth of the solidified shell.

2. The composite billet continuous casting apparatus according to claim 1, characterized in that, The physical separator (4) includes a dividing part and a converging part. The dividing part is a straight-line extending structure, and the converging part is an inwardly converging structure. The physical separator (4) includes a first water-cooled plate (401) and a second water-cooled plate (402) arranged symmetrically. The first water-cooled plate (401) and the second water-cooled plate (402) each include a straight part arranged in the vertical direction and a bent part located at the bottom of the straight part. The two straight parts constitute the dividing part, and the two bent parts constitute the converging part. In the crystallizer (2), the side of the first water-cooled plate (401) away from the second water-cooled plate (402) is the first flow channel.

3. The composite billet continuous casting apparatus according to claim 2, characterized in that, A copper plate (403) is provided on the side of the first water-cooled plate (401) and the second water-cooled plate (402) that are far apart from each other, and a high-density corundum (404) is provided at the bottom of the confluence. The first water-cooled plate (401) and the second water-cooled plate (402) are fixedly connected by the high-density corundum (404).

4. The composite billet continuous casting apparatus according to claim 2, characterized in that, The crystallizer (2) adopts a modular assembly structure. The crystallizer (2) includes a first flow channel module (201) and a second flow channel module (202) that can be replaced independently. The vertical cross-sectional shape of both the first flow channel module (201) and the second flow channel module (202) is C-shaped. The first flow channel module (201) and the second flow channel module (202) are symmetrically arranged along the length of the crystallizer (2). The first flow channel module (201) and the second flow channel module (202) have a cavity structure. The first flow channel module (201) has a first side cavity (2011) inside, and the second flow channel module (202) has a second side cavity (2021) inside. The vertical cross-sectional shape of the first side cavity (2011) and the second side cavity (2021) is C-shaped.

5. The composite billet continuous casting apparatus according to claim 4, characterized in that, The first side cavity (2011), the second side cavity (2021), the first straight water-cooled plate, and the second straight water-cooled plate are all filled with heat exchange medium.

6. The composite billet continuous casting apparatus according to claim 4, characterized in that, The first flow channel cooling system (3) includes a first parallel fixed cooling water channel (301) disposed in the first side cavity (2011), a first parallel linkage cooling water channel (302) disposed in the first straight water-cooled plate, and a first flow control component for controlling the flow rate in the first parallel fixed cooling water channel (301) and the first parallel linkage cooling water channel (302); the second flow channel cooling system (3) includes a second parallel fixed cooling water channel (303) disposed in the second side cavity (2021), a second parallel linkage cooling water channel (304) disposed in the second straight water-cooled plate, and a second flow control component for controlling the flow rate in the second parallel fixed cooling water channel (303) and the second parallel linkage cooling water channel (304).

7. The composite billet continuous casting apparatus according to claim 6, characterized in that, The width dynamic adjustment mechanism includes a servo hollow motor (5), a ball screw (6), and a nut. The servo hollow motor (5) is connected to the load-bearing frame (1). The servo hollow motor (5) is driven by the nut to drive the nut to rotate around its own axis. The nut is threadedly connected to the ball screw (6). The ball screw (6) is set in the horizontal direction and parallel to the length direction of the crystallizer (2). The two ends of the ball screw (6) are fixedly connected to the first water-cooled plate (401) and the second water-cooled plate (402), respectively.

8. The composite billet continuous casting apparatus according to claim 7, characterized in that, It also includes a control system, which includes a processor, a temperature sensor group and a position sensor. The temperature sensor group includes multiple sensors, which are respectively located in the first side cavity (2011), the inner cavity of the first water-cooled plate (401), the second side cavity (2021) and the inner cavity of the second water-cooled plate (402). The position sensor is located in the crystallizer (2) and between the first water-cooled plate (401) and the second water-cooled plate (402). The position sensor is fixedly connected to the load-bearing frame (1). The processor is signal connected to the temperature sensor group, the position sensor, the first flow control component, the second flow control component and the servo hollow motor (5). The processor is used to receive signals from the temperature sensor group and the position sensor and to issue control commands to the first flow control component, the second flow control component and the servo hollow motor (5).

9. A continuous casting method for composite steel billets, applied to the continuous casting apparatus for composite steel billets as described in claims 1-8, characterized in that, Includes the following steps: The first type of molten steel and the second type of molten steel are injected into two separate flow channels respectively; By independently controlling the cooling intensity of each flow channel, each type of molten steel undergoes initial solidification within its respective flow channel, forming a preliminary solidified shell. Controlling the solidification process of the two types of molten steel so that at the end of the physical separator (4), the first type of molten steel is in a solid or semi-solid state, while the second type of molten steel remains in a liquid or semi-solid state, so that the two meet in a "solid-liquid" state. During continuous billet drawing, two metals in a solid-liquid state meet and achieve metallurgical bonding under pressure, forming a composite billet with a gradient transition interface.

10. The continuous casting method for composite steel billets according to claim 9, characterized in that, The casting superheat of the first and second types of molten steel is in the low-temperature range of 10-20℃, and the casting speed and cooling intensity are controlled in a coordinated manner to ensure that the solidification fronts of the two types of molten steel converge at the same position.

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