A method and system for establishing a continuous cooling phase transformation temperature model for steel

Abstract

This invention provides a method and system for establishing a continuous cooling phase transformation temperature model for steel. The method includes: collecting expansion, temperature, and time data of a steel sample at two minimum cooling rates through continuous cooling transformation experiments; plotting expansion curves of the steel sample at the two minimum cooling rates based on the collected expansion, temperature, and time data; determining two phase transformation start points and two phase transformation end points based on the expansion curves; determining the intersection point of two straight lines based on the determined two phase transformation start points and two phase transformation end points; presetting an initial cooling point; determining the cooling rate for a third experiment based on the determined intersection point; conducting the third experiment; and obtaining the phase transformation start point and phase transformation end point for the third experiment; and establishing a mathematical model of phase transformation temperature versus time using the three sets of phase transformation start points and three sets of phase transformation end points. This invention enables high-precision prediction of the continuous cooling phase transformation temperature of steel with a minimum number of experiments.

Description

Technical Field

[0001] This invention relates to the field of heat treatment process optimization technology for metallic materials, and more particularly to a method and system for establishing a continuous cooling phase transformation temperature model for steel. This model is suitable for predicting phase transformation behavior under different cooling conditions and provides accurate model support for optimizing steel heat treatment processes, designing cooling paths, and controlling microstructure and properties. Background Technology

[0002] In materials science, the phase transformation characteristics of steel are one of the key factors affecting its final properties. After high-temperature deformation, the microstructure of steel undergoes a phase transformation during continuous cooling, a process described by the continuous cooling transformation curve (CCT curve). The CCT curve is an important basis for formulating hot working or heat treatment processes for metallic materials, and is widely used in the research and development of new steel grades, the optimization of rolling processes, the determination of cooling regimes, and the formulation of heat treatment processes. Through the CCT curve, the microstructure and corresponding properties of steel under actual production conditions can be predicted, thereby achieving precise control over material properties. In materials science, the phase transformation characteristics of steel are one of the key factors affecting its final properties. After high-temperature deformation, the microstructure of steel undergoes a phase transformation during continuous cooling, a process described by the continuous cooling transformation curve (CCT curve). The CCT curve is an important basis for formulating hot working or heat treatment processes for metallic materials, and is widely used in the research and development of new steel grades, the optimization of rolling processes, the determination of cooling regimes, and the formulation of heat treatment processes. Through the CCT curve, the microstructure and corresponding properties of steel under actual production conditions can be predicted, thereby achieving precise control over material properties. While existing phase transformation models possess high theoretical accuracy, they exhibit significant limitations in practical applications. First, the complexity of these models significantly increases the cost of experimental data acquisition and processing, especially when studies are required on multiple steel grades or under different process conditions, leading to long experimental cycles and low efficiency. Second, existing models struggle to predict phase transformation temperatures under cooling conditions other than specific cooling rates, limiting their widespread applicability in actual production. Furthermore, the complex model structure hinders rapid optimization and adjustment of process parameters, failing to meet the demands of modern steel production for efficient and precise control. Therefore, a novel method for establishing a continuous cooling phase transformation temperature model for steel is needed to simplify the model-building process, reduce experimental costs, and improve the model's practicality and applicability. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method and system for establishing a continuous cooling phase transformation temperature model for steel. After determining the coordinates of key phase transformation points through two basic cooling experiments, the invention intelligently generates the optimal cooling rate for the third experiment by calculating the intersection of straight lines. Finally, it uses three sets of data to establish a logarithmic phase transformation temperature prediction model, achieving high-precision prediction of the continuous cooling phase transformation temperature of steel with the fewest possible experiments.

[0004] The technical means employed in this invention are as follows: A method for establishing a continuous cooling phase transformation temperature model for steel, comprising: S1. Through continuous cooling transformation experiments, the expansion, temperature and time data of steel samples were collected at two minimum cooling rates. S2. Based on the expansion, temperature and time data of the steel sample collected in step S1 at the two minimum cooling rates, plot the expansion curves of the steel sample at the two minimum cooling rates, and determine the two phase transformation start points and two phase transformation end points based on the expansion curves. S3. Based on the two phase transformation start points and two phase transformation end points of the determined steel sample at two minimum cooling rates, determine the intersection point of the two straight lines; S4. Preset the initial cooling point, determine the cooling rate of the third experiment based on the intersection point determined in step S3, and conduct the third experiment to obtain the phase transition start point and phase transition end point of the third experiment. S5. Using three sets of phase transition start points and three sets of phase transition end points, establish a mathematical model of phase transition temperature and time.

[0005] Further, step S1 specifically includes: S11. Conduct the continuous cooling transformation curve determination experiment of steel according to the predetermined experimental process. S12. In the cooling section of the experiment, a series of cooling rates were selected, and the two cooling rates with the smallest cooling rates were selected and denoted as follows: and ; S13. After the steel sample undergoes the experimental process before cooling, it is cooled at two selected minimum cooling rates. During the experiment, the expansion amount of the sample, the corresponding temperature and time data are collected respectively.

[0006] Further, step S2 specifically includes: S21. Using the expansion, temperature and time data of the steel sample collected in step S1 at the two minimum cooling rates, plot the expansion curves of the steel sample at the two minimum cooling rates respectively. S22, Based on the minimum cooling rate of the steel sample The expansion curves below were used to determine the minimum cooling rate of the steel sample. The phase transition start temperature below Phase transition end temperature Phase transition start temperature Corresponding time and its phase transition end temperature Corresponding time This allows for the determination of the minimum cooling rate of the steel sample. The phase transition start point is The end point of phase transition is ; S23, Based on the minimum cooling rate of the steel sample The expansion curves below were used to determine the minimum cooling rate of the steel sample. The phase transition start temperature below Phase transition end temperature Phase transition start temperature Corresponding time and its phase transition end temperature Corresponding time This allows for the determination of the minimum cooling rate of the steel sample. The phase transition start point is The end point of phase transition is .

[0007] Further, step S3 specifically includes: The intersection point of the lines containing the two phase transition start points and the two phase transition end points is denoted as... The intersection point The calculation formula is as follows:

[0008] .

[0009] Further, step S4 specifically includes: S41. Assume the time and temperature at the start of cooling are respectively... and That is, setting the preset initial cooling point as ; S42. Let the cooling rate curve of the third experiment pass through the intersection point determined in step S3. Calculate the cooling rate of the third experiment. The formula is as follows:

[0010] S43. Following the predetermined experimental process, conduct a continuous cooling curve determination experiment for steel. In the cooling section of the experiment, the cooling rate is set according to the cooling rate... The experiment was designed to collect parameters such as the expansion of the sample, corresponding temperature, and time during the experiment, and to plot the steel sample at the cooling rate. The expansion curve below; S44, Based on the cooling rate of the steel sample The expansion curve below was used to determine the expansion curve of the steel sample at the cooling rate. The temperature at which the phase transition begins. and the corresponding time Temperature corresponding to the end point and the corresponding time This allows for the determination of the cooling rate of the steel sample. The phase transition start point is and the end point of phase transition .

[0011] Further, step S5 specifically includes: S51, Set the phase transition start temperature With time The relationship is represented as:

[0012] in, These are undetermined constants; S52. Substitute the three sets of phase transition initiation temperatures and times into the formula in step S51, and solve the resulting equations simultaneously to calculate the constant. The value; S53, Phase transition end temperature With time The relationship is represented as:

[0013] in, These are undetermined constants; S54. Substitute the temperatures and times at the three phase transition endpoints into the formula in step S53, and solve the resulting equations simultaneously to calculate the constant. The value of .

[0014] This invention also provides a system for establishing a continuous cooling phase transformation temperature model of steel based on the above-mentioned method for establishing a continuous cooling phase transformation temperature model of steel. The system includes: a data acquisition module, a curve plotting and phase transformation point analysis module, an intersection point determination module, a cooling rate calculation and phase transformation point analysis module, and a model establishment module, wherein: The data acquisition module is used to collect data on the expansion, temperature and time of the steel sample under two minimum cooling rates through a continuous cooling transformation experiment. The curve plotting and phase transformation point analysis module is used to plot the expansion curves of the steel sample at the two minimum cooling rates based on the collected expansion, temperature and time data of the steel sample at the two minimum cooling rates, and to determine the two phase transformation start points and two phase transformation end points based on the expansion curves. The intersection point determination module is used to determine the intersection point of two straight lines based on the two phase transformation start points and two phase transformation end points of the steel sample at two minimum cooling rates. The cooling rate calculation and phase transition point analysis module is used to preset the initial cooling point, determine the cooling rate of the third experiment based on the intersection point determined in step S3, and conduct the third experiment to obtain the phase transition start point and phase transition end point of the third experiment. The model building module is used to establish a mathematical model of phase transition temperature and time using three sets of phase transition start points and three sets of phase transition end points.

[0015] Compared with the prior art, the present invention has the following advantages: 1. Traditional methods require a large number of experiments (e.g., more than 10 sets) to establish phase transition curves, while this invention only requires 3 sets of key experiments to build a high-precision prediction model, saving time, energy consumption and material costs.

[0016] 2. This invention employs logarithmic model fitting technology combined with geometric optimization point selection, and the phase transition temperature prediction error can be controlled within ±5℃, which is superior to traditional linear regression or empirical formulas (the error is usually more than ±15℃). 3. This invention uses intelligent calculation to determine the optimal third cooling rate, avoiding manual trial and error. It can be directly integrated into heat treatment cooling control systems or process simulation software to achieve dynamic adjustment of the cooling process.

[0017] 4. This invention is applicable to low-carbon steel, medium-carbon steel and low-alloy steel, and can accurately predict the phase transformation temperatures of pearlite, bainite and martensite, providing reliable data support for composition design and process optimization.

[0018] In summary, this invention achieves high-precision prediction with the fewest number of experiments, solving the problems of low efficiency, high cost, and reliance on experience in traditional methods. It is particularly suitable for the needs of steel enterprises for refined production and intelligent upgrading. Based on the above reasons, this invention can be widely applied in fields such as the optimization of heat treatment processes for metallic materials. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products or devices.

[0023] like Figure 1 As shown, this invention provides a method for establishing a continuous cooling phase transformation temperature model for steel, comprising: S1. Through continuous cooling transformation experiments, the expansion, temperature and time data of steel samples were collected at two minimum cooling rates. S2. Based on the expansion, temperature and time data of the steel sample collected in step S1 at the two minimum cooling rates, plot the expansion curves of the steel sample at the two minimum cooling rates, and determine the two phase transformation start points and two phase transformation end points based on the expansion curves. S3. Based on the two phase transformation start points and two phase transformation end points of the determined steel sample at two minimum cooling rates, determine the intersection point of the two straight lines; S4. Preset the initial cooling point, determine the cooling rate of the third experiment based on the intersection point determined in step S3, and conduct the third experiment to obtain the phase transition start point and phase transition end point of the third experiment. S5. Using three sets of phase transition start points and three sets of phase transition end points, establish a mathematical model of phase transition temperature and time.

[0024] In a specific implementation, as a preferred embodiment of the present invention, step S1 specifically includes: S11. Conduct the continuous cooling transformation curve determination experiment of steel according to the predetermined experimental process. S12. In the cooling section of the experiment, a series of cooling rates were selected, and the two cooling rates with the smallest cooling rates were selected and denoted as follows: and ; S13. After the steel sample undergoes the experimental process before cooling, it is cooled at two selected minimum cooling rates. During the experiment, the expansion amount of the sample, the corresponding temperature and time data are collected respectively.

[0025] In a specific implementation, as a preferred embodiment of the present invention, step S2 specifically includes: S21. Using the expansion, temperature and time data of the steel sample collected in step S1 at the two minimum cooling rates, plot the expansion curves of the steel sample at the two minimum cooling rates respectively. S22, Based on the minimum cooling rate of the steel sample The expansion curves below were used to determine the minimum cooling rate of the steel sample. The phase transition start temperature below Phase transition end temperature Phase transition start temperature Corresponding time and its phase transition end temperature Corresponding time This allows for the determination of the minimum cooling rate of the steel sample. The phase transition start point is The end point of phase transition is ; S23, Based on the minimum cooling rate of the steel sample The expansion curves below were used to determine the minimum cooling rate of the steel sample. The phase transition start temperature below Phase transition end temperature Phase transition start temperature Corresponding time and its phase transition end temperature Corresponding time This allows for the determination of the minimum cooling rate of the steel sample. The phase transition start point is The end point of phase transition is .

[0026] In a specific implementation, as a preferred embodiment of the present invention, step S3 specifically includes: The intersection point of the lines containing the two phase transition start points and the two phase transition end points is denoted as... The intersection point The calculation formula is as follows:

[0027] .

[0028] In a specific implementation, as a preferred embodiment of the present invention, step S4 specifically includes: S41. Assume the time and temperature at the start of cooling are respectively... and That is, setting the preset initial cooling point as ; S42. Let the cooling rate curve of the third experiment pass through the intersection point determined in step S3. Calculate the cooling rate of the third experiment. The formula is as follows:

[0029] S43. Following the predetermined experimental process, conduct a continuous cooling curve determination experiment for steel. In the cooling section of the experiment, the cooling rate is set according to the cooling rate... The experiment was designed to collect parameters such as the expansion of the sample, corresponding temperature, and time during the experiment, and to plot the steel sample at the cooling rate. The expansion curve below; S44, Based on the cooling rate of the steel sample The expansion curve below was used to determine the expansion curve of the steel sample at the cooling rate. The temperature at which the phase transition begins. and the corresponding time Temperature corresponding to the end point and the corresponding time This allows for the determination of the cooling rate of the steel sample. The phase transition start point is and the end point of phase transition .

[0030] In a specific implementation, as a preferred embodiment of the present invention, step S5 specifically includes: S51, Set the phase transition start temperature With time The relationship is represented as:

[0031] in, These are undetermined constants; S52. Substitute the three sets of phase transition initiation temperatures and times into the formula in step S51, and solve the resulting equations simultaneously to calculate the constant. The value; S53, Phase transition end temperature With time The relationship is represented as:

[0032] in, These are undetermined constants; S54. Substitute the temperatures and times at the three phase transition endpoints into the formula in step S53, and solve the resulting equations simultaneously to calculate the constant. The value of .

[0033] This invention also provides a system for establishing a continuous cooling phase transformation temperature model for steel based on the above-mentioned method for establishing such a model. In a specific implementation, as a preferred embodiment of the present invention, it includes: a data acquisition module, a curve plotting and phase transition point analysis module, an intersection point determination module, a cooling rate calculation and phase transition point analysis module, and a model building module, wherein: The data acquisition module is used to collect data on the expansion, temperature and time of the steel sample under two minimum cooling rates through a continuous cooling transformation experiment. The curve plotting and phase transformation point analysis module is used to plot the expansion curves of the steel sample at the two minimum cooling rates based on the collected expansion, temperature and time data of the steel sample at the two minimum cooling rates, and to determine the two phase transformation start points and two phase transformation end points based on the expansion curves. The intersection point determination module is used to determine the intersection point of two straight lines based on the two phase transformation start points and two phase transformation end points of the steel sample at two minimum cooling rates. The cooling rate calculation and phase transition point analysis module is used to preset the initial cooling point, determine the cooling rate of the third experiment based on the intersection point determined in step S3, and conduct the third experiment to obtain the phase transition start point and phase transition end point of the third experiment. The model building module is used to establish a mathematical model of phase transition temperature and time using three sets of phase transition start points and three sets of phase transition end points.

[0034] The embodiments of the present invention are described simply because they correspond to those in the embodiments above. For any similarities, please refer to the descriptions in the embodiments above, which will not be elaborated here.

[0035] Example 1 Step 1: Select a low-carbon microalloyed steel as the experimental material. The experimental procedure is as follows: Place the sample in... heated to After keeping warm for 5 minutes, Cool down to ,by rate, The deformation compresses the specimen, which is then cooled at different rates. Two smaller cooling rates are set in the cooling section of the experiment. , During the experiment, the expansion of the sample, the corresponding temperature, and time parameters were collected. Step 2: Using the experimental data collected in Step 1, plot a curve on the sample expansion. Analyze this curve, based on the data collected in Step 1... , The phase transition initiation temperatures determined by the expansion curves obtained from the two cooling rates are respectively , The corresponding times are 538s and 276s, respectively. From step 1... , The phase transition termination temperatures determined by the expansion curves obtained from the two cooling rates are respectively , The corresponding times are 1297s and 546s, respectively; Step 3: Determine the intersection point of the lines containing the two phase transition start points and the two phase transition end points from Step 2. The formula is as follows:

[0036]

[0037] By combining the two formulas above, we can calculate the result. , .

[0038] Step 4: Let the cooling rate curve of the third experiment pass through the intersection point determined in Step 3. The time and temperature at the start of cooling are respectively... , The slope of the straight line determined by the initial cooling point (0, 860) and the intersection point (32, 602) determined in step 3 is the cooling rate of the third experiment. From the formula Calculated ; Step 5: Following the predetermined experimental process in Step 1, conduct the continuous cooling curve determination experiment for the steel. In the cooling section of the experiment, the cooling rate... Set as During the experiment, the expansion amount of the sample, the corresponding temperature and time parameters were collected, and a curve of the sample expansion amount was plotted. The curve was analyzed to determine the optimal cooling rate for the steel sample. The temperature at which the phase transition begins. and the corresponding time Temperature corresponding to the end point and the corresponding time ; Step 6: Based on the phase transition start temperature and time, and phase transition end temperature and time determined in Steps 2 and 5, establish a mathematical model for the phase transition start temperature. Mathematical model of phase transition end temperature ,as follows:

[0039]

[0040] Example 2 Step 1: Select a low-carbon microalloyed steel as the experimental material. The experimental procedure is as follows: Place the sample in... heated to After keeping warm for 5 minutes, Cool down to ,by rate, The deformation compresses the specimen, which is then cooled at different rates. Two smaller cooling rates are set in the cooling section of the experiment. , During the experiment, the expansion of the sample, the corresponding temperature, and time parameters were collected. Step 2: Using the experimental data collected in Step 1, plot a curve on the sample expansion. Analyze this curve, based on the data collected in Step 1... , The phase transition initiation temperatures determined by the expansion curves obtained from the two cooling rates are respectively , The corresponding times are 1048s and 550s, respectively. From step 1... , The phase transition termination temperatures determined by the expansion curves obtained from the two cooling rates are respectively , The corresponding times are 1267s and 635s, respectively; Step 3: Determine the intersection point of the lines containing the two phase transition start points and the two phase transition end points from Step 2. The formula is as follows:

[0041]

[0042] By combining the two formulas above, we can calculate the result. , .

[0043] Step 4: Let the cooling rate curve of the third experiment pass through the intersection point determined in Step 3. The time and temperature at the start of cooling are respectively... , The slope of the straight line determined by the initial cooling point (0, 1100) and the intersection point (71, 460) determined in step 3 is the cooling rate of the third experiment. From the formula Calculated ; Step 5: Following the predetermined experimental process in Step 1, conduct the continuous cooling curve determination experiment for the steel. In the cooling section of the experiment, the cooling rate... Set as During the experiment, the expansion amount of the sample, the corresponding temperature and time parameters were collected, and a curve of the sample expansion amount was plotted. The curve was analyzed to determine the optimal cooling rate for the steel sample. The temperature at which the phase transition begins. and the corresponding time Temperature corresponding to the end point and the corresponding time ; Step 6: Based on the phase transition start temperature and time, and phase transition end temperature and time determined in Steps 2 and 5, establish a mathematical model for the phase transition start temperature. Mathematical model of phase transition end temperature ,as follows:

[0044]

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for establishing a continuous cooling phase transformation temperature model for steel, characterized in that, include: S1. Through continuous cooling transformation experiments, the expansion, temperature and time data of steel samples were collected at two minimum cooling rates. S2. Based on the expansion, temperature and time data of the steel sample collected in step S1 at the two minimum cooling rates, plot the expansion curves of the steel sample at the two minimum cooling rates, and determine the two phase transformation start points and two phase transformation end points based on the expansion curves. S3. Based on the two phase transformation start points and two phase transformation end points of the determined steel sample at two minimum cooling rates, determine the intersection point of the two straight lines; S4. Preset the initial cooling point, determine the cooling rate of the third experiment based on the intersection point determined in step S3, and conduct the third experiment to obtain the phase transition start point and phase transition end point of the third experiment. S5. Using three sets of phase transition start points and three sets of phase transition end points, establish a mathematical model of phase transition temperature and time, specifically including: S51, Set the phase transition start temperature With time The relationship is represented as: in, These are undetermined constants; S52. Substitute the three sets of phase transition initiation temperatures and times into the formula in step S51, and solve the resulting equations simultaneously to calculate the constant. The value; S53, Phase transition end temperature With time The relationship is represented as: in, These are undetermined constants; S54. Substitute the temperatures and times at the three phase transition endpoints into the formula in step S53, and solve the resulting equations simultaneously to calculate the constant. The value of .

2. The method for establishing a continuous cooling phase transformation temperature model for steel according to claim 1, characterized in that, Step S1 specifically includes: S11. Conduct the continuous cooling transformation curve determination experiment of steel according to the predetermined experimental process. S12. In the cooling section of the experiment, a series of cooling rates were selected, and the two cooling rates with the smallest cooling rates were selected and denoted as follows: and ; S13. After the steel sample undergoes the experimental process before cooling, it is cooled at two selected minimum cooling rates. During the experiment, the expansion amount of the sample, the corresponding temperature and time data are collected respectively.

3. The method for establishing a continuous cooling phase transformation temperature model for steel according to claim 1, characterized in that, Step S2 specifically includes: S21. Using the expansion, temperature and time data of the steel sample collected in step S1 at the two minimum cooling rates, plot the expansion curves of the steel sample at the two minimum cooling rates respectively. S22, Based on the minimum cooling rate of the steel sample The expansion curves below were used to determine the minimum cooling rate of the steel sample. The phase transition start temperature below Phase transition end temperature Phase transition start temperature Corresponding time and its phase transition end temperature Corresponding time This allows for the determination of the minimum cooling rate of the steel sample. The phase transition start point is The end point of the phase transition is ; S23, Based on the minimum cooling rate of the steel sample The expansion curves below were used to determine the minimum cooling rate of the steel sample. The phase transition start temperature below Phase transition end temperature Phase transition start temperature Corresponding time and its phase transition end temperature Corresponding time This allows for the determination of the minimum cooling rate of the steel sample. The phase transition start point is The end point of the phase transition is .

4. The method for establishing a continuous cooling phase transformation temperature model for steel according to claim 1, characterized in that, Step S3 specifically includes: The intersection point of the lines containing the two phase transition start points and the two phase transition end points is denoted as... The intersection point The calculation formula is as follows: 。 5. The method for establishing a continuous cooling phase transformation temperature model for steel according to claim 1, characterized in that, Step S4 specifically includes: S41. Assume the time and temperature at the start of cooling are respectively... and That is, setting the preset initial cooling point as ; S42. Let the cooling rate curve of the third experiment pass through the intersection point determined in step S3. Calculate the cooling rate of the third experiment. The formula is as follows: S43. Following the predetermined experimental process, conduct a continuous cooling curve determination experiment for steel. In the cooling section of the experiment, the cooling rate is set according to the cooling rate... The experiment was designed to collect parameters such as the expansion of the sample, corresponding temperature, and time during the experiment, and to plot the steel sample at the cooling rate. The expansion curve below; S44, Based on the cooling rate of the steel sample The expansion curve below was used to determine the expansion curve of the steel sample at the cooling rate. The temperature at which the phase transition begins. and the corresponding time Temperature corresponding to the end point and the corresponding time This allows for the determination of the cooling rate of the steel sample. The phase transition start point is and the end point of phase transition .

6. A system for establishing a continuous cooling phase transformation temperature model of steel based on the method for establishing a continuous cooling phase transformation temperature model of steel according to any one of claims 1-5, characterized in that, include: The module includes a data acquisition module, a curve plotting and phase transition point analysis module, an intersection point determination module, a cooling rate calculation and phase transition point analysis module, and a model building module, among which: The data acquisition module is used to collect data on the expansion, temperature and time of the steel sample under two minimum cooling rates through a continuous cooling transformation experiment. The curve plotting and phase transformation point analysis module is used to plot the expansion curves of the steel sample at the two minimum cooling rates based on the collected expansion, temperature and time data of the steel sample at the two minimum cooling rates, and to determine the two phase transformation start points and two phase transformation end points based on the expansion curves. The intersection point determination module is used to determine the intersection point of two straight lines based on the two phase transformation start points and two phase transformation end points of the steel sample at two minimum cooling rates. The cooling rate calculation and phase transition point analysis module is used to preset the initial cooling point, determine the cooling rate of the third experiment based on the intersection point determined in step S3, and conduct the third experiment to obtain the phase transition start point and phase transition end point of the third experiment. The model building module is used to establish a mathematical model of phase transition temperature and time using three sets of phase transition start points and three sets of phase transition end points.

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