Copper mould device for characterizing heat transfer at the interface, wettability of the liquid steel and surface quality of the cast strip

Abstract

This invention belongs to the field of rapid prototyping technology for metallic materials, and relates to a copper mold device for characterizing interfacial heat transfer, wettability of molten steel, and surface quality of cast strip. The device includes an upper copper mold and a lower copper mold. The lower copper mold contains an inner cavity, cooling channels, and a thermocouple temperature measurement structure, and is connected to a rotating device to achieve rotational motion. Molten steel enters the inner cavity through an inlet located in the upper copper mold, spreads under centrifugal force, and undergoes a sub-rapid solidification process. Temperature signals are acquired using embedded thermocouples, and the interfacial heat flux density is inverted using the inverse heat conduction method. Simultaneously, wettability is quantitatively evaluated based on the contact angle, elongation, and contact area of ​​the solidified cast strip, and the quality of the cast strip is analyzed in conjunction with surface morphology. This device can simultaneously characterize interfacial heat transfer behavior, wettability, and surface quality of the cast strip under the same experimental conditions, providing experimental basis for the study of interfacial behavior and process optimization in thin strip continuous casting.

Description

Technical Field

[0001] This invention belongs to the field of rapid prototyping technology of metal materials, and relates to a copper mold device for characterizing interfacial heat transfer, wettability of molten steel and surface quality of cast strip. Background Technology

[0002] Thin strip continuous casting technology, as a cutting-edge short-process green and intelligent manufacturing technology in the iron and steel metallurgy field, is based on the core principle of molten steel directly solidifying on high-speed rotating copper crystallizing rolls and casting into a 1-5 mm thick strip. Finished or semi-finished thin strip steel can be obtained through a small amount of online rolling or without rolling altogether. The sub-rapid solidification time of the molten steel between the two rolls is only 0.15-0.6 s, and the interfacial heat flux density can reach 10 MW / m³. 2 It possesses characteristics such as high temperature, multiphase change, instantaneous and dynamic mass transfer, and heat transfer.

[0003] To delve into key scientific issues such as interfacial heat transfer and sub-rapid solidification in thin strip continuous casting, researchers have conducted extensive studies on sub-rapid solidification thermal simulation. Currently, research on sub-rapid solidification thermal simulation equipment mainly employs static casting, rapid immersion thermal simulation equipment, and droplet solidification equipment. Static casting is suitable for simulating sub-rapid solidification behavior in thin strip continuous casting, but it is relatively rudimentary, and many scientific and technological details, such as interfacial heat transfer and online microstructure evolution, are difficult to study. Rapid immersion thermal simulation equipment can effectively simulate the sub-rapid solidification process of molten steel in the crystallizing roll, obtaining as-cast thin strips close to those in industrial settings, but it lacks simulation of end-of-solidification extrusion and subsequent online hot working and processing. Droplet solidification equipment has the ability to accurately measure interfacial heat transfer and observe molten metal droplet solidification phenomena in real time, but it cannot obtain cast strips closely resembling those in actual conditions. Therefore, there is an urgent need to develop equipment that can simultaneously characterize interfacial heat transfer, molten steel wettability, and cast strip surface quality to compensate for the shortcomings of current thermal simulation equipment, improve research efficiency, and accelerate the optimization of process parameters. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention proposes a novel copper mold that combines interfacial heat transfer, molten steel wettability, and cast strip surface quality. This novel copper mold controls the sub-rapid solidification of molten steel by controlling the magnitude of centrifugal force and the roughness, material, and texture of the coating / plating layer inside the copper mold cavity. Simultaneously, it observes interfacial heat transfer behavior, molten steel wettability, and cast strip surface quality. This has important guiding significance for clarifying the coupling influence mechanism of interfacial heat transfer and molten steel wettability, thereby achieving control over the surface quality of the cast strip and simplifying the testing process.

[0005] Specifically, the technical solution adopted in this invention is as follows:

[0006] According to one aspect of the present invention, a copper mold device for characterizing interfacial heat transfer, molten steel wettability, and the surface quality of cast strips is provided.

[0007] The copper mold device includes an upper copper mold (1) and a lower copper mold (2). The upper copper mold (1) and the lower copper mold (2) are connected by a connecting device (6) to form a closed or semi-closed cavity. The upper copper mold (1) is provided with a molten steel inlet (3). The lower copper mold (2) is provided with a copper mold cavity (7) inside. A cooling water channel (5) is provided below the copper mold cavity (7). A thermocouple hole (4) is provided between the cooling water channel (5) and the cavity and is used to arrange a temperature measuring element. The lower copper mold (2) is fixed on a rotating device (8), and the rotating device (8) is used to drive the copper mold to rotate as a whole during operation, so that the molten steel entering the cavity spreads and solidifies under the action of centrifugal force. The surface of the copper mold cavity (7) is provided with an adjustable coating or surface structure to change the interface wetting behavior and heat transfer characteristics.

[0008] The copper mold device is used to simultaneously acquire interfacial heat transfer behavior, wetting characteristics, and surface quality parameters of the cast strip after solidification under the same experimental conditions.

[0009] According to the copper mold device of the present invention, preferably, the inner cavity (7) of the copper mold is surface treated by electroplating or spraying.

[0010] According to the copper mold device of the present invention, preferably, the inner cavity (7) of the copper mold is formed by shot peening / sandblasting / laser processing to form a surface with a roughness range of 5 μm to 20 μm.

[0011] According to the copper mold device of the present invention, preferably, the lower copper mold (2) is arranged with cooling water channels (5) consisting of serpentine water channels and variable cross sections, the cooling water channels (5) being 13-15 mm away from the upper surface of the base and the water channel spacing being 2-4 mm.

[0012] According to the copper mold device of the present invention, preferably, the inlet diameter of the cooling water channel (5) is 5 mm, the diameter of the serpentine water channel is 3.5 mm, the two are connected by a conical transition, and the outlet diameter is 4 mm.

[0013] According to the copper mold device of the present invention, preferably, the curvature range of the serpentine waterway is r=5mm~8mm.

[0014] According to the copper mold device of the present invention, preferably, the cooling medium in the cooling water channel (5) is water, the flow rate of the cooling medium is 20-40 L / min, and the temperature of the cooling medium is 25 ℃-40 ℃.

[0015] According to the copper mold device of the present invention, centrifugal force is used to fill the cavity with molten steel, while monitoring the interfacial heat transfer behavior, wettability and surface quality of the casting strip during the sub-rapid solidification process of the molten steel.

[0016] According to the copper mold device of the present invention, preferably, the distance between the thermocouple hole (4) and the upper surface of the upper copper mold (1) is 11-12 mm; the thermocouple used is a high-sensitivity R-type thermocouple and a K-type thermocouple.

[0017] According to the copper mold apparatus of the present invention, preferably, the transient interfacial heat flux density during the sub-rapid solidification process is calculated using a one-dimensional inverse heat conduction program (IHCP) algorithm. In the IHCP method, heat transfer is obtained by solving Fourier's law.

[0018] ;

[0019] Where c represents specific heat capacity, in J / (kg·K); p represents density, in kg / m³. 3 T represents temperature, in Kelvin (K); t represents time, in seconds (s); k represents thermal conductivity, in W / mK; x i Ω represents the location in meters (m); Ω represents the one-dimensional computational domain in the range of 1 mm to 3 mm; q represents the heat flux through the substrate surface; d represents the position of the thermocouple inserted inside the substrate, equal to 1 mm or 3 mm; Ts represents the thermocouple measurement of the substrate temperature, 1 mm or 3 mm from the substrate surface.

[0020] According to the copper mold device of the present invention, Beck JV's nonlinear estimation method is preferably used to solve the IHCP model, thereby improving the convergence speed and reducing the computational load of IHCP solution.

[0021] According to the copper mold device of the present invention, preferably, the temperature of the molten steel is controlled at 1600°C, the solidification of the molten steel is tested when the rotation speed of the rotating device (8) is 500-5000 rpm, and after the molten steel solidifies, the length of the casting strip is directly read according to the ruler (9) on the measuring surface of the copper mold.

[0022] According to the copper mold device of the present invention, preferably, the wettability assessment of the copper mold device includes a ternary coupled analysis of the casting strip extension length, the solidification interface contact angle, and the contact bottom area.

[0023] According to the copper mold device of the present invention, preferably, a mathematical model of centrifugal acceleration and the movement speed of the molten steel is established by adjusting the rotation speed of the rotating device (8), and a database of the corresponding relationship between rotation speed, casting strip length, surface roughness and solidification time is formed by comparing the actual length of the casting strip with the interface heat transfer data and combining computational fluid dynamics (CFD) simulation.

[0024] According to the copper mold device of the present invention, preferably, the molten steel inlet (3) is placed below the molten metal outlet. After the rotation speed is controlled to stabilize to a predetermined value, the melt reaching the set temperature enters the copper mold device through the molten steel inlet (3) and fills the cavity under the action of centrifugal force and solidifies rapidly. During the solidification process, the temperature signal can be recorded in real time by thermocouples and data acquisition system.

[0025] According to the copper mold device of the present invention, preferably, after solidification, the connecting device (6) is opened, the upper copper mold (1) and the lower copper mold (2) are separated, the obtained cast strip sample is taken out, the heat flux density is calculated by the real-time heat flow data through the heat transfer inverse problem algorithm, the wettability of the molten steel is compared by comparing the wettability index of the cast strip at the same rotation speed, and the surface quality of the cast strip is compared by comparing the surface morphology of the cast strip at the same rotation speed.

[0026] Beneficial technical effects

[0027] 1. This device employs a rotating disk to drive the movement of a copper mold, using centrifugal force to bring the molten steel into contact with the water-cooled copper mold, thus achieving a sub-rapid solidification process. This dynamic simulation method more closely approximates actual industrial production processes, especially for studying the solidification characteristics of molten steel under rapid motion conditions.

[0028] 2. The base is equipped with a new type of water channel with a serpentine shape and variable cross-section, which can increase the cooling capacity by 20% under the same cooling water flow rate, ensure the flow stability at the corners, avoid turbulence, and ensure the stability of the cooling capacity; at the same time, it makes the cooling water delivery smoother.

[0029] 3. Coatings, platings, and texturing treatments on the surface of copper molds can simulate different crystallization roller parameters and study their effects on the sub-rapid solidification process. Multiple surface treatment experiments can be completed in a single device, reducing experimental costs, improving experimental efficiency, and obtaining comprehensive process optimization data.

[0030] This device, through multi-dimensional analysis of solidified samples, not only provides detailed data on interfacial heat transfer behavior but also assesses the wettability of molten steel. This comprehensive analytical approach can provide important experimental evidence for optimizing continuous casting processes and improving the quality and performance of thin strip products. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0032] Figure 1 This is a schematic diagram of the copper mold device of the present invention.

[0033] The reference numerals in the attached diagram refer to the following: 1-Upper copper mold, 2-Lower copper mold, 3-Steel droplet inlet, 4-Thermocouple hole, 5-Cooling water pipe, 6-Connecting device, 7-Inner cavity of copper mold, 8-Turntable, 9-Ruler.

[0034] Figure 2 This is a schematic diagram of the cooling water channel structure.

[0035] Figure 3 The surface of the copper mold is coated with a NiCr-Cr3C2 coating.

[0036] Figure 4 The curves show the change in heat flux density at the boron-containing and boron-free interfaces over time. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0038] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0039] This invention provides a copper mold device for characterizing interfacial heat transfer, molten steel wettability, and the surface quality of the casting strip. The copper mold device includes an upper copper mold (1) and a lower copper mold (2), which are connected by a connecting device (6) to form a closed or semi-closed cavity. The upper copper mold (1) is provided with a molten steel inlet (3). The lower copper mold (2) is provided with a copper mold inner cavity (7), and a cooling water channel (5) is provided below the copper mold inner cavity. A thermocouple hole (4) is provided between the cooling water channel and the cavity for arranging temperature measuring elements. The lower copper mold (2) is fixed on a rotating device (8) to drive the copper mold to rotate as a whole during operation, so that the molten steel entering the cavity spreads and solidifies under the action of centrifugal force. The surface of the copper mold inner cavity is provided with an adjustable coating or surface structure to change the interfacial wetting behavior and heat transfer characteristics.

[0040] The device is used to simultaneously acquire interfacial heat transfer behavior, wetting characteristics, and surface quality parameters of the cast strip after solidification under the same experimental conditions.

[0041] As a preferred embodiment, the rotational speed of the turntable is 500 r / min-1000 r / min.

[0042] As a preferred embodiment, the inner cavity of the copper mold is surface-treated by electroplating or spraying, with a Cr or Ni-Cr composite coating or a Ni60 or WC coating applied to the copper surface to improve the wear resistance of the copper surface.

[0043] As a preferred embodiment, the inner cavity of the copper mold is textured using methods such as shot peening, sandblasting, laser processing, or grinding. For example, shot peening can create different pit morphologies, which can increase the contact area between the cooling water and the surface of the crystallizing roller, thereby improving cooling efficiency. Furthermore, shot peening introduces residual compressive stress on the surface, improving fatigue resistance and extending service life.

[0044] As a preferred option, the roughness of the inner cavity of the copper mold is in the range of 5 μm-20 μm.

[0045] As a preferred option, a new type of water channel with a serpentine shape and variable cross-section is arranged in the copper mold. The cooling water channel (5) is 13-15 mm away from the upper surface of the base and the water channel spacing is 2-4 mm. The previous straight water channel is changed to the current serpentine water channel, which increases the flow channel length and extends the residence time of the coolant in the system, so that it can fully absorb heat.

[0046] As a preferred embodiment, the cooling water channel (5) has an inlet of 5mm, a serpentine channel of 3.5mm, a conical transition to reduce flow loss, and an outlet of 4mm to gradually restore pressure and reduce outlet resistance. The inlet is larger than the outlet to compensate for the high pressure drop in the serpentine section and ensure sufficient flow. The serpentine section is the working area for the solidification of molten steel, which reduces the cross-sectional area, increases the flow velocity, enhances heat transfer, and gradually restores pressure at the outlet to reduce outlet resistance.

[0047] As a preferred embodiment, the curvature range of the serpentine waterway is r = 5 mm to 8 mm.

[0048] As a preferred embodiment, the cooling medium is water, with a flow rate of 20-40 L / min and a water temperature of 25℃-40℃.

[0049] As a preferred approach, centrifugal force is used to fill the mold cavity with molten steel, while monitoring the interfacial heat transfer behavior, wettability, and surface quality of the casting strip during the sub-rapid solidification process.

[0050] As a preferred embodiment, the thermocouple hole (4) is 11-12 mm away from the upper surface of the upper copper mold (1). The thermocouples used are high-sensitivity R-type and K-type thermocouples. During solidification, the temperature signal is recorded in real time by thermocouples embedded at different depths inside the copper substrate and their associated data acquisition system.

[0051] As a preferred approach, the transient interfacial heat flux density during sub-rapid solidification is calculated using the one-dimensional inverse heat conduction program (IHCP). In the IHCP method, heat transfer is obtained by solving Fourier's law:

[0052] ;

[0053] Where c represents specific heat capacity, in J / (kg·K); p represents density, in kg / m³. 3 T represents temperature, in Kelvin (K); t represents time, in seconds (s); k represents thermal conductivity, in W / mK; x i The values ​​represent the location in meters (m); Ω represents the one-dimensional computational domain ranging from 1 mm to 3 mm; q represents the heat flux through the substrate surface; d represents the position of the thermocouple inserted inside the substrate, equal to 1 mm or 3 mm; and Ts represents the thermocouple measurement of the substrate temperature, 1 mm or 3 mm from the substrate surface. Beck JV's nonlinear estimation method is used to solve the IHCP model, improving the convergence speed and reducing the computational cost of IHCP solution. Based on the above calculation model, the interfacial heat flux variation curve with solidification time during steel solidification can be obtained. The heat transfer characteristics under a certain parameter can be evaluated based on the peak heat flux and thermal conductivity.

[0054] As a preferred option, the temperature of the molten steel is fixed at 1600℃, and the solidification of the molten steel is tested at 500-5000 rpm. After the molten steel solidifies, the casting strip is taken out for analysis. The length of the casting strip can be directly read according to the ruler (9) on the measuring surface of the copper mold.

[0055] As a preferred approach, the wettability assessment of the copper mold includes a ternary coupled analysis of the casting strip extension length, solidification interface contact angle, and contact bottom area:

[0056] 1. Cast strip elongation: Defined as the ratio of the actual length L of the cast strip to the theoretical length L0 of the mold cavity (L / L0).

[0057] 2. Solidification contact angle: After sampling, measure the steel / copper boundary angle θ on the metallographic sample, preferably selecting the average value of three equidistant measurement points 5 mm from the root of the casting band;

[0058] 3. Contact area ratio: The solidification interface is reconstructed by three-dimensional laser scanning, and the ratio (A / A0) of the actual contact area A to the projected area A0 of the mold cavity is calculated.

[0059] The wettability index (WI) is calculated using the following formula: The closer the wettability index is to 1, the better the wettability.

[0060] As a preferred approach, multi-scale analysis of the surface quality of the cast strip is employed: combining macroscopic linear density statistics (overall defect distribution) with microscopic grain boundary penetration depth measurement (severity of local defects) to reveal the cross-scale evolution of defects; the evaluation of depressions uses a combination of aspect ratio (local morphology) and area ratio (global coverage) to quantify the comprehensive impact of surface unevenness.

[0061] As a preferred approach, in existing technologies, surface quality analysis is mostly performed using discrete single-scale methods (such as macroscopic or microscopic analysis only). Multi-scale collaborative analysis (across macroscopic-microscopic and morphological-structural dimensions) avoids the limitations of single-scale analysis and enables comprehensive diagnosis and quantitative assessment of surface defects.

[0062] As a preferred approach, a mathematical model of centrifugal acceleration (G-value) and molten steel velocity is established by adjusting the centrifugal rotation speed (e.g., a gradient setting of 500-5000 rpm). This model can be verified by comparing the actual length of the cast strip with interfacial heat transfer data and by combining computational fluid dynamics (CFD) simulations, thus forming a database of the correspondence between rotation speed, cast strip length, surface roughness, and solidification time.

[0063] As a preferred approach, by systematically correlating centrifugal casting process parameters (such as rotation speed) with solidification characteristics (strip length, surface roughness, solidification time, etc.), a quantitative relationship between process parameters, solidification behavior, and strip quality is established, thus providing a scientific basis for optimizing thin-strip continuous casting processes. This guides process parameter selection; the database allows for rapid matching of specific strip quality requirements. Traditional processes rely on trial-and-error methods to adjust parameters, while the database provides quantitative data, reducing the number of experiments by more than 40%. Secondly, the database offers process scalability, supporting the development of new alloys (such as high-entropy alloys) and enabling rapid adaptation to different material systems by adjusting parameter mapping relationships.

[0064]

[0065] This invention also provides a novel copper mold application that combines interfacial heat transfer, molten steel wettability, and casting surface quality. It utilizes centrifugal force to fill the mold cavity with molten steel, while simultaneously monitoring the interfacial heat transfer behavior, molten steel wettability, and casting surface quality of the molten steel during the sub-rapid solidification process.

[0066] As a preferred embodiment, the top opening of the copper mold is placed below the molten metal outlet. After the rotation speed is stabilized to a predetermined value, the molten metal reaching the set temperature enters the copper mold cavity through the steel droplet inlet. Under the action of centrifugal force, it fills the copper mold cavity and rapidly solidifies. During the solidification process, the temperature signal can be recorded in real time via thermocouples and a data acquisition system.

[0067] As a preferred method, after solidification, the connecting device is opened, the upper and lower copper molds are separated, and the resulting cast strip sample is taken out. Real-time heat flux data is used to calculate the heat flux density using an inverse heat transfer problem algorithm; the wettability of the molten steel can be compared by comparing the wettability index of the cast strip at the same rotation speed; and the surface morphology of the cast strip at the same rotation speed can be compared to determine the quality of the cast strip surface.

[0068] The following are embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention. All other embodiments that can be obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0069] The technical solution of the present invention will be further described in detail below through specific embodiments and comparative examples.

[0070] Example 1:

[0071] like Figure 1 As shown, this embodiment provides a novel copper mold that combines interfacial heat transfer, molten steel wettability, and casting strip surface quality. The novel copper mold consists of an upper copper mold and a lower copper mold, which are connected by a connecting device. The top opening of the upper copper mold is the molten steel droplet inlet. The lower copper mold has an inner cavity, with a cooling water pipe at the bottom and a thermocouple hole at the top. The lower copper mold is fixed to a turntable to achieve synchronous rotation, with the turntable rotating at a speed of 500 r / min.

[0072] The copper mold is made of copper, and the inner cavity of the copper mold is plated with chromium. The morphology of the inner cavity of the copper mold is a pitted type obtained by shot peening, and the roughness of the inner cavity of the copper mold is 7 μm.

[0073] Example 2:

[0074] The present invention has the same structure as that of Embodiment 1, except that the inner cavity of the copper mold is a Cr3C2-NiCr coating obtained by supersonic flame spraying.

[0075] Example 3:

[0076] The present invention has the same structure as Embodiment 1, except that the rotational speed of the turntable is 800 r / min.

[0077] Example 4:

[0078] The structure of this invention is exactly the same as that of Example 1, except that: the temperature of the molten steel is fixed at 1600℃ and the rotation speed is 1000rpm. 3.5% Si steel with 20ppm boron and boron-free silicon steel are selected. It is found that the heat flux peak of the boron-containing silicon steel is higher than that of the boron-free silicon steel, and the casting strip length is longer than that of the boron-free silicon steel. This indicates that adding boron to 3.5% Si steel will improve the wettability between the molten steel and the surface of the crystallizing roll and promote interfacial heat transfer.

[0079] Example 5:

[0080] A solidification experiment of molten metal was conducted using the novel copper mold provided in Example 1. The process was as follows: the inlet of the molten steel droplet was placed below the outlet of the molten metal; the cooling medium circulation was activated, and circulating water at a constant temperature circulated within the mold. The rotating disk switch was turned on, and the rotation speed was stabilized at the desired speed; the temperature acquisition device was connected, and heat flow data was recorded after the molten metal droplet fell. Under the action of centrifugal force, the molten steel filled the cavity of the copper mold and solidified rapidly.

[0081] After solidification, the connecting device is opened, the upper and lower copper molds are separated, and the resulting cast strip sample is taken out. Real-time heat flux data is used to calculate the heat flux density using an inverse heat transfer problem algorithm; the wettability of the molten steel can be compared by comparing the lengths of the cast strips at the same rotational speed; and the surface morphology of the cast strips at the same rotational speed can be compared to determine the quality of the surface.

[0082] This invention acquires temperature signals using embedded thermocouples and inverts the interfacial heat flux density using the reverse heat conduction method. Simultaneously, it quantitatively evaluates wettability based on the contact angle, elongation, and contact area of ​​the solidified strip, and analyzes the strip quality in conjunction with surface morphology. This device enables simultaneous characterization of interfacial heat transfer behavior, wetting characteristics, and strip surface quality under the same experimental conditions, providing experimental basis for the study of interfacial behavior and process optimization in thin strip continuous casting.

[0083] The above description is only a specific embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A copper mold device for characterizing interfacial heat transfer, molten steel wettability, and the surface quality of cast strips, characterized in that: The copper mold device includes an upper copper mold (1) and a lower copper mold (2). The upper copper mold (1) and the lower copper mold (2) are connected by a connecting device (6) to form a closed or semi-closed cavity. The upper copper mold (1) is provided with a molten steel inlet (3). The lower copper mold (2) is provided with a copper mold cavity (7) inside. A cooling water channel (5) is provided below the copper mold cavity (7). A thermocouple hole (4) is provided between the cooling water channel (5) and the cavity and is used to arrange a temperature measuring element. The lower copper mold (2) is fixed on a rotating device (8), and the rotating device (8) is used to drive the copper mold to rotate as a whole during operation, so that the molten steel entering the cavity spreads and solidifies under the action of centrifugal force. The surface of the copper mold cavity (7) is provided with an adjustable coating or surface structure to change the interface wetting behavior and heat transfer characteristics. The copper mold device is used to simultaneously acquire interfacial heat transfer behavior, wetting characteristics, and surface quality parameters of the cast strip after solidification under the same experimental conditions.

2. The copper mold device according to claim 1, characterized in that: The inner cavity (7) of the copper mold is surface treated by electroplating or spraying.

3. The copper mold device according to claim 1, characterized in that: The inner cavity (7) of the copper mold is formed by shot peening / sandblasting / laser processing to create a surface with a roughness range of 5 μm to 20 μm.

4. The copper mold device according to claim 1, characterized in that: The lower copper mold (2) is arranged with cooling water channels (5) consisting of serpentine water channels and variable cross sections. The cooling water channels (5) are 13-15 mm away from the upper surface of the base, and the spacing between the water channels is 2-4 mm.

5. The copper mold device according to claim 4, characterized in that: The inlet diameter of the cooling water channel (5) is 5 mm, the diameter of the serpentine water channel is 3.5 mm, the two are connected by a conical transition, and the outlet diameter is 4 mm.

6. The copper mold device according to claim 5, characterized in that: The curvature range of the serpentine waterway is r = 5 mm to 8 mm.

7. The copper mold device according to claim 4, characterized in that: The cooling medium in the cooling water channel (5) is water, the flow rate of the cooling medium is 20-40 L / min, and the temperature of the cooling medium is 25 ℃-40 ℃.

8. The copper mold device according to claims 1-6, characterized in that: Centrifugal force is used to fill the cavity with molten steel, while the interfacial heat transfer behavior, wettability, and surface quality of the casting strip are monitored during the sub-rapid solidification process.

9. The copper mold device according to claim 8, characterized in that: The distance between the thermocouple hole (4) and the upper surface of the upper copper mold (1) is 11-12 mm; the thermocouples used are high-sensitivity R-type thermocouples and K-type thermocouples.

10. The copper mold device according to claim 8, characterized in that: The transient interfacial heat flux density during the sub-rapid solidification process is calculated using the one-dimensional inverse heat conduction program (IHCP). In the IHCP method, heat transfer is obtained by solving Fourier's law. ； Where c represents specific heat capacity, in J / (kg·K); p represents density, in kg / m³. 3 T represents temperature, in Kelvin (K); t represents time, in seconds (s); k represents thermal conductivity, in W / mK; x i Ω represents the location in meters (m); Ω represents the one-dimensional computational domain ranging from 1 mm to 3 mm; q represents the heat flux through the substrate surface; d represents the position of the thermocouple inserted inside the substrate, equal to 1 mm or 3 mm; Ts represents the thermocouple measurement of the substrate temperature, 1 mm or 3 mm from the substrate surface.

11. The copper mold device according to claim 10, characterized in that: Beck JV's nonlinear estimation method is used to solve the IHCP model, which improves the convergence speed and reduces the computational cost of solving the IHCP.

12. The copper mold device according to claim 8, characterized in that: The temperature of the molten steel is controlled at 1600℃. The solidification of the molten steel is tested when the rotation speed of the rotating device (8) is 500-5000 rpm. After the molten steel solidifies, the length of the casting strip is directly read according to the ruler (9) on the measuring surface of the copper mold.

13. The copper mold device according to claim 8, characterized in that: The wettability assessment of the copper mold device includes a ternary coupled analysis of the casting strip extension length, solidification interface contact angle, and contact bottom area.

14. The copper mold device according to claim 1, characterized in that: By adjusting the rotation speed of the rotating device (8), a mathematical model of centrifugal acceleration and the movement speed of the molten steel is established. By comparing the actual length of the casting strip with the interface heat transfer data and combining it with computational fluid dynamics (CFD) simulation, a database of the corresponding relationships between rotation speed, casting strip length, surface roughness, solidification time, and other solidification characteristics is formed.

15. The copper mold device according to claim 8, characterized in that: The molten steel inlet (3) is placed below the molten metal outlet. After the rotation speed is stabilized to a predetermined value, the melt that reaches the set temperature enters the copper mold device through the molten steel inlet (3) and fills the cavity under the action of centrifugal force and solidifies rapidly. During the solidification process, the temperature signal can be recorded in real time through thermocouples and data acquisition system.

16. The copper mold device according to claim 8, characterized in that: After solidification, the connecting device (6) is opened, the upper copper mold (1) and the lower copper mold (2) are separated, and the cast strip sample is taken out. The heat flux density is calculated by the heat transfer inverse problem algorithm based on the real-time heat flow data. The wettability of the molten steel is compared by comparing the wettability index of the cast strip at the same rotation speed. The surface quality of the cast strip is compared by comparing the surface morphology of the cast strip at the same rotation speed.

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