Method for solving solidification characteristic parameters in semi‑continuous casting process

Abstract

The present application relates to the technical field of metal semi-continuous casting, and in particular to a method for solving solidification characteristic parameters in a semi‑continuous casting process. The method for solving solidification characteristic parameters in a semi‑continuous casting process provided in the present application comprises: first, establishing a three-dimensional geometric model on the basis of a casting device and an ingot shape, and then solving a flow field and a temperature field in a semi-continuous casting process on the basis of thermal-fluid coupling numerical simulation; and when casting enters a steady state, solving cooling curves on the basis of streamlines or pathlines, and then solving a plurality of solidification characteristic parameters in the semi-continuous casting process on the basis of the cooling curves together with the streamlines or the pathlines.

Description

A method for solving solidification characteristic parameters in a semi-continuous casting process.

[0001] Cross-reference

[0002] This application claims priority to Chinese Patent Application No. 202411463410X, filed on October 21, 2024, entitled "A Method for Solving Solidification Characteristic Parameters in a Semi-Continuous Casting Process", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of metal semi-continuous casting technology, specifically relating to a method for solving solidification characteristic parameters in a semi-continuous casting process. Background Technology

[0004] Semi-continuous casting of aluminum alloys is the most important process in aluminum processing. The quality of the aluminum alloy ingot largely determines the subsequent processing and the final service performance of the product. The cooling curve, with time (t) on the horizontal axis and temperature (T) on the vertical axis, records the solidification history of each point in the ingot, as shown in Figure 1. The cooling history or cooling curve of the solidification process at each point in the ingot is an important tool for studying the solidification behavior of metals.

[0005] Multiple solidification characteristic parameters can be analyzed through cooling curves, such as the solid fraction curve of solidification (horizontal axis is time (t), vertical axis is solid fraction (fs)), solidification time, cooling rate, hot cracking sensitivity, etc. These solidification characteristics are closely related to ingot porosity, macro segregation, grain size and second phase precipitation. Obtaining accurate ingot cooling curves is the key to understanding and studying the formation mechanism of ingot defects and evaluating ingot defects.

[0006] Based on the flow characteristics of aluminum alloys during solidification, there are several key temperature points: the liquidus T L And dendrite overlap temperature T COH and solidus line T S Based on the above key points, the solidification process can be divided into the liquid phase region (T>T). L ), two-phase region (T) L ≥T≥T S ) and the solid phase region (T <T S Based on fluidity, the two phases can be further divided into a slurry zone (T). L ≥T>T COH ) and pasty area (T COH ≥T≥T LAs shown in Figure 2, primary aluminum begins to nucleate and grow in the slurry zone, but the primary aluminum atoms do not overlap and can flow with the melt. When the temperature drops below the overlap temperature, the primary aluminum atoms overlap to form a dendritic network and cannot flow, while the remaining liquid phase flows between the dendrites.

[0007] Currently, methods for obtaining ingot cooling profiles include: ① embedding thermocouples in the casting mold beforehand. After the molten metal is poured into the mold, the thermocouples record the historical temperature data at that location as the solidification process proceeds. Simultaneously, the thermocouples solidify inside the ingot (Reference: Anyalebechi, PN, Rouns, TN, Sanders, RE (2016). Effects of Cooling Rate and Grain Refining on Constituent Phase Particle Size in As-Cast 3004 Alloy. In: Grandfield, JF, Eskin, DG (eds) Essential Readings in Light Metals. Springer, Cham. https: / / doi.org / 10.1007 / 978-3-319-48228-6_60). However, this method can lead to the scrapping of the cast product. ② The temperature field of the casting process is calculated by numerical simulation, and historical temperature data is extracted. These data are then processed (slope or secant slope) to obtain the cooling curve (Reference: Wu Yongfu, Zhang Baocun, Wang Ning, et al. Influence of cooling rate on eutectic silicon modification during DC semi-continuous casting of 4032 aluminum alloy round ingots [J]. Journal of Aeronautical Materials, 2021, 41(02): 53-60.). However, these methods do not take into account the slurry zone (overlap temperature T). COH The above description of the solid phase flowing with the melt does not match reality, resulting in inaccurate cooling curve calculations, which may mislead when studying solidification issues or guiding production. Summary of the Invention

[0008] To address the problems existing in the prior art, this application provides a method for solving the solidification characteristic parameters of the semi-continuous casting process. By using a data processing method based on thermal-fluid coupling numerical simulation, the internal flow of the slurry zone is fully considered, and the cooling curve of the semi-continuous casting process is accurately calculated. Then, by combining the cooling curve, streamlines, and traces, multiple solidification characteristic parameters of the semi-continuous casting process are solved.

[0009] This application specifically includes the following:

[0010] A method for solving solidification characteristic parameters in a semi-continuous casting process includes the following steps:

[0011] S1, Solve for flow field and temperature field: Establish a three-dimensional geometric model based on the casting equipment and ingot shape, perform thermal-fluid coupling numerical simulation of the semi-continuous casting process, and solve for the flow field and temperature field of the semi-continuous casting process.

[0012] S2, Solve the cooling curve: After casting enters a steady state, extract the streamline or trace of the solidification process with the point of the solidified area on the cross-section of the ingot as the endpoint, and derive the node coordinates, temperature T and time t on the streamline or trace. Use the time t and temperature T on the streamline or trace to solve the cooling curve; repeat the above operation to obtain the cooling curve of any point on the cross-section of the entire ingot.

[0013] S3, Cooling Curve Data Analysis: Analyze the cooling curve at a specific point to obtain solidification characteristic parameters for that point, including solidification time, cooling rate, and thermal cracking sensitivity.

[0014] A streamline is a curve describing the direction and velocity of fluid (molten metal) at a given moment. A pathline is the trajectory of a fluid particle (which can be understood as a small unit within the molten metal during alloy casting) over a continuous period of time. The methods disclosed in this application include two schemes: using streamlines to solve for the solidification characteristic parameters of the semi-continuous casting process and using pathlines. Both methods are within the scope of protection of this application.

[0015] Optionally, S3 also includes: analyzing a sufficient number of cooling curves to obtain the distribution of solidification characteristic parameters across the entire cross-section of the ingot.

[0016] Optionally, the solidification characteristic parameters include solidification time, which refers to the time from the liquidus temperature T during the solidification process. L To solidus temperature T S The time elapsed, the method for calculating the solidification time, is: t L-S =t S -t L

[0017] in,

[0018] t L-S Indicates the solidification time;

[0019] t L This indicates that the temperature on a certain streamline or traceline reaches the liquidus temperature T. L Time;

[0020] t S This indicates that the temperature on the streamline or traceline reaches the solidus temperature T. S The time.

[0021] Optionally, the solidification characteristic parameters include the instantaneous cooling rate, which is calculated as follows:

[0022] in,

[0023] This represents the instantaneous cooling rate of the i-th node on a streamline or trace.

[0024] T i This represents the temperature of the i-th node on the streamline or trace.

[0025] T i+1 This represents the temperature of the (i+1)th node on the streamline or trace.

[0026] t i This represents the time corresponding to the i-th node on the streamline or path;

[0027] t i+1 This represents the time corresponding to the (i+1)th node on the streamline or trace.

[0028] Optionally, the solidification characteristic parameters include the cooling rate within a certain cooling temperature range, and the methods for solving the cooling rate include:

[0029] a. Determine the upper and lower temperature limits of the cooling temperature range;

[0030] b. Obtain the time corresponding to the upper and lower temperature limits on a certain streamline or traceline;

[0031] c. Then calculate the cooling rate using the following formula:

[0032] in,

[0033] Indicates the cooling rate within a cooling temperature range;

[0034] T up Indicates the upper limit of the cooling temperature range;

[0035] T down Indicates the lower limit of the cooling temperature range;

[0036] t up This indicates the time corresponding to the upper temperature limit on the streamline or trace.

[0037] t down This indicates the time corresponding to the lower limit of temperature on the streamline or trace.

[0038] Optionally, the coordinates of the endpoint of the streamline or trace can be assigned to the calculated cooling rate. This gives the cooling rate at a point on the cross-section of the ingot.

[0039] Optionally, the cooling rate can be calculated for all points on the cross-section of the ingot to obtain the cooling rate distribution of the ingot cross-section.

[0040] Optionally, when studying the preferentially precipitated high-temperature phases in the alloy, T up The value is equal to the precipitation temperature of the high-temperature phase, T. down The value is higher than the temperature corresponding to the solidus line of the alloy; the high-temperature phase refers to the alloy composition in which nucleation occurs above the liquidus line.

[0041] Optionally, when studying the cooling rate of nascent aluminum grains within the liquid cavity, T up The value is equal to the liquidus temperature T. l T down The value is equal to the solidus temperature T. solid A liquid cavity refers to a region of molten metal that has not yet fully solidified and forms inside an alloy ingot during the solidification process due to uneven cooling conditions.

[0042] Alternatively, when studying the cooling rate after overlapping, T up The value is equal to the dendrite lap temperature T. COH T down The value is equal to the solidus temperature T. solid .

[0043] Optionally, the solidification characteristic parameters include hot cracking susceptibility, and the solution method for hot cracking susceptibility is as follows:

[0044] in,

[0045] HCS stands for thermal crack susceptibility, which refers to the ratio of the duration of the brittle phase in the later stages of solidification to the duration of the stress relief phase.

[0046] t V Indicates the duration of the stress relief period;

[0047] t R Indicates the duration of the fragile period in the later stage of solidification;

[0048] t 99 This indicates the time corresponding to when the solid fraction reaches 99%;

[0049] t 90 This indicates the time corresponding to when the solid fraction reaches 90%.

[0050] t 40 This indicates the time corresponding to when the solid fraction reaches 40%.

[0051] The beneficial effects of this application are:

[0052] (1) The method for solving the solidification characteristic parameters of the semi-continuous casting process provided in this application first establishes a three-dimensional geometric model based on the casting equipment and ingot shape, and then obtains the flow field and temperature field of the semi-continuous casting process based on thermal-fluid coupling numerical simulation; then, after the casting enters a steady state, the cooling curve is obtained based on streamlines or traces, and then, by combining the cooling curve, streamlines or traces, various solidification characteristic parameters of the semi-continuous casting process are obtained. This application fully considers the internal flow of the slurry zone in the semi-continuous casting process when calculating the cooling curve, and the obtained cooling curve is more accurate than the methods in the prior art.

[0053] (2) The method for solving solidification characteristic parameters of the semi-continuous casting process disclosed in this application has wide applicability. It can be used not only for the semi-continuous casting of aluminum alloys, but also for different casting processes of other metal materials, such as continuous casting of steel, semi-continuous casting and horizontal continuous casting of copper alloys, and casting forming processes such as sand core casting, metal mold casting, high pressure casting, and low pressure casting of cast iron, aluminum alloys, magnesium alloys, and copper alloys. Attached Figure Description

[0054] Figure 1 is a schematic diagram of the cooling curve;

[0055] Figure 2 is a comparison diagram of the zone division and cooling path in the semi-continuous casting process;

[0056] Figure 3 is a schematic diagram of the ingot streamline and cooling curve;

[0057] Figure 4 is a flow diagram of the center of a 400mm diameter 7050 aluminum alloy ingot in an embodiment of this application.

[0058] Figure 5 is a comparison diagram of the cooling curves of 7050 aluminum alloy with a diameter of 400mm in the embodiments and comparative examples of this application;

[0059] Figure 6 is a comparison of the instantaneous cooling rates of 7050 aluminum alloy with a diameter of 400mm in the embodiments and comparative examples of this application.

[0060] Figure 7 is a streamline diagram of a 5083 alloy flat ingot with dimensions of 420×1620mm in an embodiment of this application;

[0061] Figure 8 is a comparison diagram of the cooling rate in the thickness direction of a 5083 alloy flat ingot with dimensions of 420×1620mm in the embodiments and comparative examples of this application. Detailed Implementation

[0062] A method for solving solidification characteristic parameters in a semi-continuous casting process includes the following steps:

[0063] S1, Solve for flow field and temperature field: Establish a three-dimensional geometric model based on the casting equipment and ingot shape, perform thermal-fluid coupling numerical simulation of the semi-continuous casting process, and solve for the flow field and temperature field of the semi-continuous casting process.

[0064] S2, Solve the cooling curve: After casting enters a steady state, extract the streamline or trace of the solidification process with the point of the solidified area on the cross-section of the ingot as the endpoint, and derive the node coordinates, temperature T and time t on the streamline or trace. Use the time t and temperature T on the streamline or trace to solve the cooling curve; repeat the above operation to obtain the cooling curve of any point on the cross-section of the entire ingot.

[0065] S3, Cooling Curve Data Analysis: Analyze the cooling curve at a certain point to obtain the solidification characteristic parameters at that point. Analyze a sufficient number of cooling curves to obtain the distribution of solidification characteristic parameters across the entire cross-section of the ingot.

[0066] The solidification characteristic parameters of this application include solidification time, cooling rate, and thermal cracking sensitivity, among which,

[0067] (1) Solidification time refers to the time from the liquidus temperature T during the solidification process. L To solidus temperature T S The time elapsed, the method for calculating the solidification time, is: t L-S =t S -t L (1)

[0068] in,

[0069] t L-S Indicates the solidification time;

[0070] t L This indicates that the temperature on a certain streamline or traceline reaches the liquidus temperature T. L Time;

[0071] t S This indicates that the temperature on the streamline or traceline reaches the solidus temperature T. S The time.

[0072] (2) The solution method for the instantaneous cooling rate is as follows:

[0073] in,

[0074] This represents the instantaneous cooling rate of the i-th node on a streamline or trace.

[0075] T i This represents the temperature of the i-th node on the streamline or trace.

[0076] T i+1 This represents the temperature of the (i+1)th node on the streamline or trace.

[0077] t iThis represents the streamline time corresponding to the i-th node on the streamline or pathline.

[0078] t i+1 This represents the streamline time corresponding to the (i+1)th node on the streamline or trace.

[0079] (3) The methods for determining the cooling rate within a certain cooling temperature range include:

[0080] a. Determine the upper and lower temperature limits of the cooling temperature range;

[0081] b. Obtain the time corresponding to the upper and lower temperature limits on a certain streamline or traceline;

[0082] c. Then calculate the cooling rate using the following formula:

[0083] in,

[0084] Indicates the cooling rate within a cooling temperature range;

[0085] T up Indicates the upper limit of the cooling temperature range;

[0086] T down Indicates the lower limit of the cooling temperature range;

[0087] t up This indicates the time corresponding to the upper temperature limit on the streamline or trace.

[0088] t down This indicates the time corresponding to the lower limit of temperature on the streamline or trace.

[0089] Assign the coordinates of the streamline endpoint to the calculated cooling rate. The cooling rate at a point on the cross-section of the ingot can then be obtained.

[0090] The cooling rate is calculated for all points on the cross-section of the ingot to obtain the cooling rate distribution of the ingot cross-section.

[0091] When studying the preferential precipitation of high-temperature phases in alloys: T up The value is equal to the precipitation temperature of the high-temperature phase, T. down The value is higher than the temperature corresponding to the solidus line of the alloy; the high-temperature phase refers to the alloy composition in which nucleation occurs above the liquidus line.

[0092] When studying the cooling rate of nascent aluminum grains within a liquid cavity: T up The value is equal to the liquidus temperature T. l T down The value is equal to the solidus temperature T. solid .

[0093] When studying the cooling rate after overlapping: T up The value is equal to the dendrite lap temperature T. COH T down The value is equal to the solidus temperature T. solid .

[0094] (4) The solution method for hot cracking sensitivity is as follows:

[0095] in,

[0096] HCS stands for Hot Tearing Sensitivity, which refers to the ratio of the duration of the brittle phase in the later stages of solidification to the duration of the stress relief phase (Reference: Nallathambi, AK, Penumakala, PK, Specht, E. (2013). Review of Hot Tearing Studies in Al Alloys during Direct Chill Casting. In: Krane, MJM, Jardy, A., Williamson, RL, Beaman, JJ (eds) Proceedings of the 2013 International Symposium on Liquid Metal Processing & Casting. Springer, Cham. https: / / doi.org / 10.1007 / 978-3-319-48102-9_40).

[0097] t V Indicates the duration of the stress relief period;

[0098] t R Indicates the duration of the fragile period in the later stage of solidification;

[0099] t 99 This indicates the time corresponding to when the solid fraction reaches 99%;

[0100] t 90 This indicates the time corresponding to when the solid fraction reaches 90%.

[0101] t 40 This indicates the time corresponding to when the solid fraction reaches 40%.

[0102] The present application will now be described in detail with reference to Figures 1-8 and specific embodiments, wherein Figure 1 is a schematic diagram of cooling curves; Figure 2 is a comparison diagram of the semi-continuous casting process area division and cooling path; Figure 3 is a schematic diagram of ingot streamline and cooling curves; Figure 4 is a streamline diagram of the center of a 400mm diameter 7050 aluminum alloy ingot in an embodiment of the present application; Figure 5 is a comparison diagram of the cooling curves of a 400mm diameter 7050 aluminum alloy in an embodiment of the present application and a comparative example; Figure 6 is a comparison diagram of the instantaneous cooling rate of a 400mm diameter 7050 aluminum alloy in an embodiment of the present application and a comparative example; Figure 7 is a streamline diagram of a 420×1620mm 5083 alloy flat ingot in an embodiment of the present application; Figure 8 is a comparison diagram of the cooling rate in the thickness direction of a 420×1620mm 5083 alloy flat ingot in an embodiment of the present application and a comparative example. The embodiments shown below do not limit the scope of the invention as described in the claims. Furthermore, the complete contents of the structures represented in the following embodiments are not limited to those necessary for the solution of the invention described in the claims.

[0103] Example 1

[0104] The casting temperature of 7050 alloy is about 700℃. During the semi-continuous casting process, Al3Zr phase will precipitate above the alloy liquidus temperature. The cooling rate has a certain influence on the precipitation of Al3Zr phase. Therefore, to study the precipitation behavior of Al3Zr phase, it is necessary to solve the cooling rate during the solidification process.

[0105] This embodiment uses the method disclosed in this application to solve the cooling rate of the core of a 400mm diameter 7050 aluminum alloy round ingot, including the following steps:

[0106] S1, Solve for flow field and temperature field: Establish a simulation model of aluminum alloy casting process, calculate the temperature field and flow field from the start of the machine to 2000s of casting, at which time the inside of the ingot has reached a steady state;

[0107] S2, Solve the cooling curve: Taking the bottom of the ingot as the endpoint, extract the streamlines and output the nodes on the streamlines, as shown in Figure 4. Extract the temperature and streamline time on the streamlines and process the data to obtain the temperature-time curve during the cooling process, as shown in Figure 5.

[0108] S3, Solving for the cooling rate: The cooling rate is solved by formula (2) at adjacent points on the convection line, and the result is shown in Figure 6.

[0109] As shown in Figure 6, the highest cooling rate can reach 10℃ / s in the precipitation temperature range of Al3Zr phase, which is 630 to 700℃.

[0110] Example 2

[0111] The distribution of ingot cooling rate has a significant impact on the microstructure of the ingot. The faster cooling rate at the edge of the ingot results in finer grains, while the slower cooling rate at the core results in coarser grains.

[0112] This embodiment uses the method of this application to analyze the cooling rate along the thickness direction of a 420×1620mm flat ingot (5083 casting), with a casting temperature of 700℃ and a casting speed of 50mm / min. The steps include:

[0113] S1, Solve for the flow field and temperature field: Establish a steady-state simulation model of the aluminum alloy casting process, and extract the temperature field and flow field data after the calculation converges.

[0114] S2, Extract streamlines: Draw a straight line with the center of the bottom width direction of the ingot, set 10 points on the straight line, and draw a streamline diagram backward from these 10 points, as shown in Figure 7.

[0115] S3, In this embodiment, the interval average cooling rate calculation method is used, where the interval temperature is from the liquidus line (=639℃) to the solidus line (=450℃) of the alloy. For each streamline, for T up and T down Interpolation is performed to obtain the corresponding streamline time t. up and t down The cooling rate of each streamline is calculated according to formula (3).

[0116] The cooling rate along the thickness of the ingot obtained in this embodiment is shown in Figure 8. Due to the presence of the flow divider bag in the flat ingot, the molten metal flows out of the flow divider bag outlet, then flows towards the small face of the ingot, and then remains in the lower part of the liquid cavity before returning to the center of the ingot. That is, after the initial phase nucleation, it undergoes a relatively long movement inside the liquid cavity, hence the slow cooling rate. The cooling rate at the center of the ingot is approximately 0.166℃ / s.

[0117] Comparative Example 1

[0118] This comparative example calculates the cooling rate of the core of a 400mm diameter 7050 aluminum alloy round ingot using traditional methods, including the following steps:

[0119] S1, Solve for flow field and temperature field: Establish a simulation model of aluminum alloy casting process, calculate the temperature field and flow field from the start of the machine to 2000s of casting. At this time, the ingot has reached a steady state. This step is the same as in Example 1.

[0120] S2, extract the temperature-time curve at the center of the ingot, as shown in Figure 5;

[0121] S3. Find the tangent to the temperature-time curve to obtain the cooling rate, as shown in Figure 6.

[0122] In this comparative example, the cooling rate was less than 1℃ / s at 630℃-700℃. The initially formed Al3Zr phase flows in the melt with the flow field. The flow velocity of the melt is significantly greater than the casting velocity, so the Al3Zr phase can quickly deposit to the bottom of the liquid cavity (compared to vertical deposition to the bottom of the liquid cavity at the casting velocity), thus taking less time and having a faster cooling rate in the liquid phase.

[0123] As can be seen from Figures 5-6, the traditional method does not take into account the slurry zone (overlap temperature T). COH The above description of the solid phase flowing with the melt deviates from the actual situation. However, this application fully considers the internal flow of the slurry zone during the semi-continuous casting process when calculating the cooling curve, and the resulting cooling curve and instantaneous cooling rate are more accurate than those of existing methods.

[0124] Comparative Example 2

[0125] This comparative example analyzes the cooling rate along the thickness direction of a 420×1620mm flat 5083 ingot using traditional methods, including the following steps:

[0126] S1. Establish a steady-state simulation model of the aluminum alloy casting process. This step is the same as in Example 2.

[0127] S2, after convergence, extract the temperature-time curves of 10 points (vertically downwards according to the casting direction) in the thickness direction of the ingot;

[0128] S3, calculate the cooling rate according to formula (3), and the cooling rate is shown in Figure 8.

[0129] As can be seen from Figure 8, the traditional method does not take into account the flow of the solid phase in the slurry zone with the melt, which is inconsistent with reality. However, this application fully considers the internal flow of the slurry zone during the semi-continuous casting process when calculating the cooling curve, and the obtained cooling rate is more accurate than the existing methods in the prior art.

[0130] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Industrial applicability

[0131] The solution provided in this application can be applied to the field of semi-continuous metal casting technology. In this application embodiment, a three-dimensional geometric model is first established based on the casting equipment and ingot shape. Then, the flow field and temperature field of the semi-continuous casting process are obtained based on thermal-fluid coupling numerical simulation. After the casting enters a steady state, the cooling curve is obtained based on streamlines or traces. Then, by combining the cooling curve, streamlines, or traces, various solidification characteristic parameters of the semi-continuous casting process are obtained. This application fully considers the internal flow of the slurry zone in the semi-continuous casting process when calculating the cooling curve, and the obtained cooling curve is more accurate than existing methods in the prior art.

Claims

1. A method for solving solidification characteristic parameters in a semi-continuous casting process, comprising the following steps: S1, Solve for flow field and temperature field: Establish a three-dimensional geometric model based on the casting equipment and ingot shape, perform thermal-fluid coupling numerical simulation of the semi-continuous casting process, and solve for the flow field and temperature field of the semi-continuous casting process. S2, Solve the cooling curve: After casting enters a steady state, extract the streamline or trace of the solidification process with the point of the solidified area on the cross-section of the ingot as the endpoint, and derive the node coordinates, temperature T and time t on the streamline or trace. Use the time t and temperature T on the streamline or trace to solve the cooling curve; repeat the above operation to obtain the cooling curve of any point on the cross-section of the entire ingot. S3, Cooling Curve Data Analysis: Perform data analysis on the cooling curve of a certain point to obtain the solidification characteristic parameters of that point.

2. The method for solving solidification characteristic parameters in a semi-continuous casting process according to claim 1, wherein, S3 further includes: analyzing the obtained multiple cooling curves to obtain the distribution of solidification characteristic parameters on the entire cross-section of the ingot.

3. The method for solving solidification characteristic parameters in a semi-continuous casting process according to claim 1, wherein, The solidification characteristic parameters include solidification time, which refers to the time from the liquidus temperature T during the solidification process. L To solidus temperature T S The time elapsed, the method for calculating the solidification time, is: t L-S =t S -t L in, t L-S Indicates the solidification time; t L This indicates that the temperature on a certain streamline or traceline reaches the liquidus temperature T. L Time; t S This indicates that the temperature on the streamline or traceline reaches the solidus temperature T. S The time.

4. The method for solving solidification characteristic parameters in a semi-continuous casting process according to claim 1, wherein, The solidification characteristic parameters include the instantaneous cooling rate, which is calculated as follows: in, This represents the instantaneous cooling rate of the i-th node on a streamline or trace. T i This represents the temperature of the i-th node on the streamline or trace; T i+1 This represents the temperature of the (i+1)th node on the streamline or trace; t i This represents the time corresponding to the i-th node on the streamline or trace; t i+1 This represents the time corresponding to the (i+1)th node on the streamline or trace.

5. The method for solving solidification characteristic parameters in a semi-continuous casting process according to claim 1, wherein, The solidification characteristic parameters include the cooling rate within a certain cooling temperature range, and the method for solving the cooling rate includes: a. Determine the upper and lower temperature limits of the cooling temperature range; b. Obtain the time corresponding to the upper and lower temperature limits on a certain streamline or traceline; c. Then calculate the cooling rate using the following formula: in, This indicates the cooling rate within the specified cooling temperature range; T up This indicates the upper limit of the cooling temperature range; T down This indicates the lower limit of the cooling temperature range; t up This indicates the time corresponding to the upper temperature limit on the streamline or trace; t down This indicates the time corresponding to the lower limit of the temperature on the streamline or trace.

6. The method for solving solidification characteristic parameters in a semi-continuous casting process according to claim 5, wherein, Assign the coordinates of the endpoint of the streamline or trace to the calculated cooling rate. This gives the cooling rate at a point on the cross-section of the ingot.

7. The method for solving solidification characteristic parameters in a semi-continuous casting process according to claim 6, wherein, The cooling rate is calculated for all points on the cross-section of the ingot to obtain the cooling rate distribution of the ingot cross-section.

8. The method for solving the solidification characteristic parameters of the semi-continuous casting process according to any one of claims 5-7, wherein, When studying the preferentially precipitated high-temperature phases in alloys, the T up The value is equal to the precipitation temperature of the high-temperature phase, and the value of T is equal to the precipitation temperature of the high-temperature phase. down The value is higher than the temperature corresponding to the solidus line of the alloy; the high-temperature phase refers to the alloy composition in which nucleation occurs above the liquidus line.

9. The method for solving the solidification characteristic parameters of the semi-continuous casting process according to any one of claims 5-7, wherein, When studying the cooling rate of nascent aluminum grains within a liquid cavity, the T up The value is equal to the liquidus temperature T. l The T down The value is equal to the solidus temperature T. solid .

10. The method for solving the solidification characteristic parameters of the semi-continuous casting process according to any one of claims 5-7, wherein, When studying the cooling rate after overlapping, the T up The value is equal to the dendrite lap temperature T. coh T down The value is equal to the solidus temperature T. solid .

11. The method for solving solidification characteristic parameters in a semi-continuous casting process according to claim 1, wherein, The solidification characteristic parameters include thermal cracking sensitivity, and the method for solving the thermal cracking sensitivity is as follows: in, HCS stands for thermal cracking sensitivity, which refers to the ratio of the duration of the brittle period in the later stage of solidification to the duration of the stress relief period. t V Indicates the duration of the stress relief period; t R Indicates the duration of the fragile period in the later stage of solidification; t 99 This indicates the time corresponding to when the solid fraction reaches 99%; t 90 This indicates the time corresponding to when the solid fraction reaches 90%. t 40 This indicates the time corresponding to when the solid fraction reaches 40%.

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