A new method for measuring the diffusion coefficient of a substance in inclusions in steel

Abstract

The application discloses a kind of new methods for measuring the diffusion coefficient of substance inclusions in steel, comprising: obtaining experimental material, pretreatment is carried out to experimental material;Wherein, experimental material includes steel sample and inclusion;The high temperature modification experiment of pretreated experimental material is carried out by high temperature confocal equipment, and the composition of inclusion at different time is analyzed according to experimental data;The initial condition of kinetic model is obtained, and the mass transfer coefficient of inclusion is estimated based on initial condition and inclusion composition analysis.The new method for measuring the diffusion coefficient of substance inclusions in steel provided by the application effectively estimates the diffusion coefficient of substance inclusions in steel liquid, thereby providing important basic data for the optimization of steelmaking process.The method of the application has important experimental and production guiding effect and good application and popularization prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a new method for measuring the diffusion coefficient of inclusions in steel. Background Art

[0002] With the increasing demand for high-quality steel from users, the control of non-metallic inclusion content in steel has become particularly important. In order to achieve high cleanliness of steel, the inclusions in the steel must be accurately monitored and controlled. For killed steel, alumina inclusions are the most important inclusions, which have a high melting point and high hardness. A large number of alumina inclusions in the steel matrix will cause stress concentration, seriously affecting the plasticity, toughness and fatigue resistance of the steel. At the same time, a large number of alumina inclusions will be deposited inside the submerged nozzle, causing nozzle nodules and blockages, seriously affecting the smooth progress of the continuous casting process. At present, the calcium treatment process is the most commonly used way to solve the problem of alumina inclusions in steel. Calcium treatment can modify alumina inclusions into spherical calcium aluminate inclusions with a lower melting point, which are easy to remove from the molten steel. Even if there is still a small amount of residue, its harm to the performance of the steel is less than that of solid alumina inclusions.

[0003] In recent years, to effectively control the composition of alumina inclusions in steel, metallurgists have developed various kinetic models to better predict the shape, size, quantity, and distribution of inclusions during the modification process. A commonly used model is the multilayer unreacted core model, which considers the influence of a single substance during the diffusion process. Furthermore, in establishing these kinetic models, inclusions in steel are often assumed to be spherical for ease of calculation. However, in actual production, inclusions often exist in molten steel in irregular shapes, leading to controversy surrounding the kinetic parameters and other calculation results ultimately proposed based on this assumption.

[0004] At present, high temperature confocal microscopy is a new research method in the field of iron and steel metallurgy. A large number of scholars use high temperature confocal microscopy equipment to study the collision behavior of inclusions in steel and the dissolution behavior of inclusions in slag. However, due to the limitations of the experimental method of high temperature confocal microscopy, there are few studies on the modification behavior of inclusions. The predecessors mainly used high temperature confocal microscopy to observe the modification process of endogenous alumina inclusions in steel into spherical calcium aluminate inclusions in situ, and did not analyze the composition of the target inclusions at different times. This is because the experimental method has some shortcomings: (1) Since the number of endogenous alumina inclusions on the surface of molten steel is large and they will collide, it becomes particularly difficult to track and observe the modification process of the target inclusions in steel; (2) The accuracy of the starting time of the modification of alumina inclusions in steel cannot be guaranteed; (3) The operation process is complicated and difficult to control. In order to meet the need to predict the composition change of calcium-treated alumina inclusions, the present invention provides a new method for measuring the diffusion coefficient of a substance in steel inclusions. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention proposes a new method for measuring the diffusion coefficient of a substance in inclusions in steel to solve the problems existing in the above prior art.

[0006] To achieve the above object, the present invention provides a new method for measuring the diffusion coefficient of a substance in inclusions in steel, comprising:

[0007] Acquiring experimental materials and pre-treating the experimental materials; wherein the experimental materials include steel samples and inclusions;

[0008] The pre-treated experimental materials were subjected to high-temperature modification experiments using a high-temperature confocal instrument, and the inclusion composition at different times was analyzed based on the experimental data.

[0009] The initial conditions of the kinetic model are obtained, and the mass transfer coefficient of inclusions is estimated based on the initial conditions and inclusion composition analysis.

[0010] Optionally, the process of pre-treating the steel sample includes:

[0011] After cutting the steel sample into several cylinders of the same preset size, the steel sample is cold mounted using UV glue; the prepared steel sample is polished and cleaned step by step; after polishing, it is placed in a container filled with alcohol for ultrasonic cleaning.

[0012] Optionally, the preset dimensions include height and diameter, the height ranges from 3-5 mm, and the diameter ranges from 5-10 mm.

[0013] Optionally, the process of pre-treating the inclusions includes:

[0014] Slag containing the ingredients required for the experiment is obtained and ground and mixed to obtain powdered preheated slag; the powdered preheated slag is pressed into round cakes of a preset size, the round cakes are heated to prepare pre-melted slag, and the pre-melted slag is crushed and selected to screen out inclusion particles that meet size conditions; wherein the preset size conditions include the size and the error of each group of inclusion particles, the size is 100-300μm, and the error between the sizes of each group of inclusion particles does not exceed 40μm.

[0015] Optionally, when the temperature is raised to prepare the pre-melted slag, the holding temperature needs to be controlled to be 50-100° C. higher than the complete melting temperature of the slag, and the holding time needs to be controlled to be 20-30 minutes.

[0016] Optionally, a high-temperature modification experiment is performed on the pre-treated experimental material using a high-temperature confocal device. The process of analyzing the inclusion composition at different times based on the experimental data includes:

[0017] The reaction time corresponding to each group of inclusion particles is obtained through preliminary experiments, and a high-temperature modification experiment is performed on the pretreated experimental material based on the reaction time. When the reaction time is reached, helium is injected into the heating furnace to cool the material. The experimental material is removed from the experiment, and the composition of the inclusion particles is analyzed using a scanning electron microscope to obtain the inclusion composition. The cooling rate is controlled within a range of 300-1000°C.

[0018] Optionally, the initial conditions of the kinetic model include the density and volume of the inclusion particles; the density of the inclusion particles is calculated based on the relationship between the molar volume of the oxide and the temperature using the following formula:

[0019] ρ liquidslag =∑x MO ·ρ MO ;

[0020]

[0021] Where, ρ liquid slag is the density of liquid slag, kg·m -3 ;x MO is the mass percentage of different oxides in the slag, wt%; ρ MO is the density of different oxides in the slag, kg·m -3 ;M MO is the molar mass of different oxides in the slag, kg·mol -1 ; Z MO is the molar volume of different oxides in the slag, m 3 ·mol -1 .

[0022] Optionally, the volume of inclusion particles is calculated as follows:

[0023]

[0024] V is the volume of liquid inclusion particles, m -3 ; R is the radius of the liquid inclusion particles after being flattened on the surface of the steel sample, m; θ is the contact angle between the liquid inclusion particles and the solid steel.

[0025] Compared with the prior art, the present invention has the following advantages and technical effects:

[0026] The present invention discloses a new method for measuring the diffusion coefficient of a substance in inclusions in steel. First, in the preparation of experimental materials, the experimental materials include steel samples and inclusions. The steel samples need to be cut into columns of a certain size. The inclusion particles need to be heated using a high-temperature device to prepare pre-melted slag with a certain ratio. The pre-melted slag is crushed and selected to select inclusion particles of appropriate size. Then, a high-temperature laser confocal device is used to perform a high-temperature modification experiment on the prepared experimental sample, and an electron microscope is used to analyze the inclusion composition at different times. Finally, the initial conditions required for the kinetic model are collected, and the mass transfer coefficient of the substance in the inclusion is estimated. The present invention uses a high-temperature confocal device to simulate the molten steel-inclusion reaction experiment, combines an electron microscope to analyze the composition of the inclusions at different times, collects the parameters required for the model, and finally estimates the mass transfer coefficient of the substance in the inclusion. The calculated results are similar to those of previous studies, proving the feasibility of the experiment. The method provided by the present invention has important experimental and production guidance functions and good application and promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0028] Figure 1 Schematic diagram of steel sample preparation and chemical analysis according to an embodiment of the present invention;

[0029] Figure 2 Schematic diagram of the preparation process of inclusion particles according to an embodiment of the present invention;

[0030] Figure 3 Schematic diagram of the entire process of changes of inclusion particles on the steel surface according to an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of changes in the composition of inclusion particles over time according to an embodiment of the present invention;

[0032] Figure 5 Schematic diagram of the projection of liquid inclusions on the solid steel surface and their shape on the solid surface according to an embodiment of the present invention;

[0033] Figure 6 The steel in the embodiment of the present invention Schematic diagram of the relationship between and reaction time;

[0034] Figure 7 The steel in the embodiment of the present invention Schematic diagram of the relationship between and reaction time;

[0035] Figure 8Schematic diagrams showing the effect of steels with different aluminum contents on the evolution of inclusion particle composition according to an embodiment of the present invention, (a) is a schematic diagram when T.Al = 145 ppm, (b) is a schematic diagram when T.Al = 280 ppm, and (c) is a schematic diagram when T.Al = 420 ppm;

[0036] Figure 9 Figure 2 is the change in the logarithmic values ​​of the Al2O3 and SiO2 contents in the steel with a T.Al of 145 ppm according to the embodiment of the present invention over time; (a) is the change in Al2O3, and (b) is the change in SiO2;

[0037] Figure 10 Figure 2 is the logarithmic change of the Al2O3 and SiO2 contents in the steel with a T.Al value of 280 ppm according to an embodiment of the present invention over time; (a) is the change of Al2O3, and (b) is the change of SiO2;

[0038] Figure 11 Figure 2 is the logarithmic value of the change in Al2O3 and SiO2 content in the steel with T.Al=420ppm according to the embodiment of the present invention over time; (a) is the change in Al2O3, and (b) is the change in SiO2;

[0039] Figure 12 Schematic diagram of a method flow in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0041] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0042] Example 1

[0043] like Figure 12 As shown, this embodiment provides a new method for measuring the diffusion coefficient of a substance in inclusions in steel. Taking the measurement of the mass transfer coefficient of CaO in CaO-Al2O3-MgO-SiO2 inclusion particles as an example, the specific operating steps are as follows:

[0044] S1: In the preparation of experimental materials, the experimental materials include steel samples and inclusions. The steel samples need to be cut into columns of a certain size. The inclusion particles need to be prepared by using high-temperature equipment to heat a certain proportion of slag to prepare pre-melted slag. The pre-melted slag is crushed and selected to select inclusion particles of appropriate size.

[0045] S2: Use high-temperature laser confocal equipment to conduct high-temperature modification experiments, and use electron microscope equipment to analyze the composition of inclusions at different times;

[0046] S3: Collect the initial conditions required for the kinetic model and estimate the mass transfer coefficient of the species in the inclusion.

[0047] As a preferred embodiment, the steel sample in step S1 is industrial Al deoxidized steel, and its specific composition is shown in Table 1. The Al deoxidized steel is cut into several cylinders with a diameter of 5 mm and a height of 3 mm. In order to ensure clear imaging when observing the steel sample under a high-temperature laser confocal microscope, the upper and lower bottom surfaces of the sample must be kept strictly parallel. The steel sample is cold mounted using UV glue, and then the steel sample is polished step by step using different types of sandpaper (300#, 600#, 800#, 1200#, 2400#). It is then cleaned with alcohol, and then polished with 8μm and 1μm polishing liquid. Finally, the polished steel sample is placed in a beaker filled with alcohol, and the beaker is placed in an ultrasonic cleaner for cleaning for 5 minutes to thoroughly remove impurities and contaminants remaining on the surface. The steel sample preparation and chemical analysis scheme are as follows. Figure 1 shown.

[0048] Table 1

[0049]

[0050] As a preferred embodiment, the main components of the inclusion particles in step S1 are CaO, Al2O3, MgO and SiO2. First, CaO (Chinese medicine, purity ≥98%), Al2O3 (Chinese medicine, purity ≥99%), SiO2 (Chinese medicine, purity ≥99%) and MgO (Chinese medicine, purity ≥99%) reagents are prepared in a certain proportion to obtain slag of the required composition for the experiment, which is then placed in a quartz grinding crucible and ground and mixed to ensure that the preheated slag has a uniform composition. Then, the powder sample is placed in a specific tableting mold, and then appropriate pressure is applied to compress the powder into a diameter of 10 mm. The crucible is 3 mm high and has a round cake shape; finally, the platinum crucible is placed in the heating furnace chamber of the high-temperature confocal microscope (CSLM), melted at 1600°C in the heating furnace of the CSLM and kept warm for 20 minutes to achieve the purpose of uniform slag composition, and then He gas is used to rapidly cool at 1200°C per minute to obtain the slag sample required for the experiment to prevent the crystallization of the slag sample from affecting the subsequent inclusion particles. The initial composition is close to the slag composition of the ratio before the experiment, and the inclusion particles are subjected to XRF analysis, where the CaO, Al2O3, MgO and SiO2 content are 55.50%, 29.77%, 7.98% and 6.75% respectively. Finally, the platinum crucible is taken out, and the pre-melted slag in the platinum crucible is crushed with pointed stainless steel tweezers, and particles of suitable size are selected from it as inclusion particles for subsequent CSLM experiments. The specific operation method is as follows: Figure 2 shown.

[0051] As a preferred embodiment, in the high temperature modification experiment in step S2, as the temperature rises to 1732.4K, the inclusion particles begin to melt, and their irregular edges gradually become smooth. When the temperature continues to rise to 1786.6K, the inclusion particles further melt, and their shape changes to spherical. When the temperature reaches 1857.1K, the steel surface placed below the slag begins to melt, and the slag begins to float on the surface of the molten steel. This moment is the start time of the reaction between the inclusions and the molten steel. Subsequently, the temperature is controlled and the reaction time is recorded. The whole process of the changes of the inclusion particles on the steel surface is as follows: Figure 3 As shown. In order to prevent the inclusion particles from moving too fast and leaving the observation range, the argon flow rate needs to be reduced during the experiment to avoid violent fluctuations on the surface of the molten steel. When the reaction time reaches the target duration, the cooling program begins by filling the heating furnace with He gas to achieve rapid cooling. The steel sample is then taken out and a scanning electron microscope is used to analyze the composition of the inclusion particles. During the entire transfer process, the steel sample can be placed in an alcohol bottle to prevent its surface from being contaminated. During the entire high-temperature confocal experiment, the high-temperature confocal microscope and the scanning electron microscope need to work repeatedly in sequence, and only the reaction time of the inclusions and the molten steel needs to be changed. Figure 4 is the change of inclusion particle composition over time.

[0052] Furthermore, the initial conditions of the kinetic model include the density and volume of the inclusion particles; wherein the density of the inclusion particles is calculated based on the relationship between the molar volume of the oxide and the temperature using the following formula:

[0053] ρ liquid slag =∑x MO ·ρ MO (1)

[0054]

[0055] Where, ρ liquid slag is the density of liquid slag, kg·m -3 ;x MO is the mass percentage of different oxides in the slag, wt%; ρ MO is the density of different oxides in the slag, kg·m -3 ;M MO is the molar mass of different oxides in the slag, kg·mol -1 ; Z MO is the molar volume of different oxides in the slag, m 3 ·mol -1 .

[0056] Furthermore, the volume calculation formula of inclusion particles is as follows:

[0057]

[0058] V is the volume of liquid inclusion particles, m -3 ; R is the radius of the liquid inclusion particles after being flattened on the surface of the steel sample, m; θ is the contact angle between the liquid inclusion particles and the solid steel.

[0059] As a preferred embodiment, the volume of inclusion particles in the initial conditions of the kinetic model in step S2 is calculated. According to literature search, the contact angle between the liquid inclusion particles and the solid steel is 83.18°. Using formula (3), the volume of the liquid inclusion particles is 1.87×10 -11 m 3 . Figure 5 It is the projection of liquid inclusions on the solid steel surface and its shape on the solid surface.

[0060] As a preferred embodiment, the inclusion particle density calculation of the initial condition in the kinetic model in step S2 is to bring the inclusion particle composition measured by XRF into formulas (1) to (2). The density of the liquid inclusion particles is calculated to be 2891 kg·m -3 .

[0061] Specifically, the relationship between the molar volume of the oxide and the temperature T is shown in Table 2.

[0062] Table 2

[0063]

[0064] As a preferred embodiment, in step S3, the mass transfer coefficient of the substance in the inclusion is estimated. Based on the unreacted core model, since the [Al] content in the molten steel is relatively high, the boundary layer diffusion of [Al] on the molten steel side of the inclusion will not become a limiting link. At the same time, the chemical reaction at the interface is usually relatively fast, so the limiting link of the reaction process may be the mass transfer of CaO or Al2O3 in the inclusion particles. Assuming that the rate-controlling link of the reaction is the diffusion of CaO inside the inclusion, its mass transfer rate is:

[0065]

[0066] Among them, (%CaO) inc is the mass fraction of CaO in inclusions at different times; is the mass fraction of CaO at the molten steel-inclusion interface; A is the contact area between inclusion and molten steel, m 2 ; V is the volume of inclusions, m 3 ;k CaO is the diffusion coefficient of CaO in inclusions, m / s. Integrating formula 4 yields:

[0067]

[0068] The experimental results are introduced into formula 6 and linear fitting is performed. The diffusion coefficient of Al2O3 in inclusions is also fitted. The fitting results of the diffusion coefficients of CaO and Al2O3 in inclusions are as follows: Figure 6 and Figure 7 As shown in the figure, it is found that the logarithmic value of the change of CaO content in inclusions is linearly related to the reaction time, indicating that the limiting factor of inclusions is the diffusion coefficient of CaO in inclusions. The calculated diffusion coefficient is about 3.77×10 -6 m·s -1 .

[0069] Example 2

[0070] The technical solution proposed in the present invention is: a method for measuring the diffusion coefficient of a substance in inclusions in steel. Taking the measurement of the mass transfer coefficient of SiO2 in CaO-Al2O3-MgO-SiO2 inclusion particles as an example, the specific operating steps are as follows:

[0071] S1: In the preparation of experimental materials, the experimental materials include steel samples and inclusions. The steel samples need to be cut into columns of a certain size. The inclusion particles need to be prepared by using high-temperature equipment to heat a certain proportion of slag to prepare pre-melted slag. The pre-melted slag is crushed and selected to select inclusion particles of appropriate size.

[0072] S2: Use high-temperature laser confocal equipment to conduct high-temperature modification experiments, and use electron microscope equipment to analyze the composition of inclusions at different times;

[0073] S3: Collect the initial conditions required for the kinetic model and estimate the mass transfer coefficient of the species in the inclusion.

[0074] Preferably, in step S1, the steel sample is Al-deoxidized steel smelted in the laboratory, and its specific composition is shown in Table 3. Al-deoxidized steel with different contents is cut into several cylinders with a diameter of 5 mm and a height of 3 mm. To ensure clear imaging when observing the steel sample under a high-temperature laser confocal microscope, the upper and lower bottom surfaces of the sample must be kept strictly parallel. The steel sample is cold-mounted using UV glue, and the steel sample is polished step by step using different types of sandpaper (300#, 600#, 800#, 1200#, 2400#). It is then cleaned with alcohol, and then polished with 8μm and 1μm polishing liquids. Finally, the polished steel sample is placed in a beaker filled with alcohol, and the beaker is placed in an ultrasonic cleaner for cleaning for 5 minutes to thoroughly remove impurities and contaminants remaining on the surface.

[0075] Table 3

[0076]

[0077] Preferably, the main components of the inclusion particles in step S1 are CaO, Al2O3, and SiO2. First, CaO (Chinese medicine, purity ≥98%), Al2O3 (Chinese medicine, purity ≥99%), and SiO2 (Chinese medicine, purity ≥99%) reagents are prepared in a certain proportion to obtain slag of the required composition for the experiment, which is then placed in a quartz grinding crucible and ground and mixed to ensure that the preheated slag composition is uniform; then, the powder sample is placed in a specific tableting mold, and then appropriate pressure is applied to compress the powder into a round cake with a diameter of 10 mm and a height of 3 mm. Finally, the platinum crucible was placed in the heating chamber of a high-temperature confocal microscope (CSLM). The slag was melted at 1600°C and held there for 20 minutes to achieve a uniform slag composition. He gas was then used to rapidly cool the slag sample at 1200°C per minute to prevent crystallization from affecting subsequent inclusion particles. The initial composition of the inclusion particles was close to that of the pre-experimental slag. XRF analysis of the inclusion particles revealed CaO, Al2O3, and SiO2 contents of 17.02%, 39.22%, and 43.75%, respectively. The platinum crucible was then removed and the pre-melted slag was crushed using pointed stainless steel tweezers. Appropriately sized particles were selected from the slag sample to serve as inclusion particles for subsequent CSLM experiments.

[0078] Preferably, the high temperature modification experiment in step S2 is conducted on steels with different aluminum contents and inclusion particles of a certain size. Figure 8 Effect of steels with different aluminum contents on the evolution of inclusion particle composition.

[0079] Preferably, in step S2, the volume of inclusion particles under the initial conditions in the kinetic model is calculated. According to literature search, the contact angle between liquid inclusion particles and solid steel is 36°. Using formula 3, the volumes of the three groups of liquid inclusion particles are 6.64×10 -13 m 3 , 6.60×10 -13 m 3 and 6.31×10 -13 m 3 .

[0080] Preferably, in step S2, the density of inclusion particles in the initial condition of the kinetic model is calculated by substituting the composition of the inclusion particles measured by XRF into formulas (1) to (2). The density of the liquid inclusion particles is calculated to be 2817.4 kg·m -3 .

[0081] Preferably, in step S3, the mass transfer coefficient of the substance in the inclusion is estimated. Based on the unreacted core model, since the [Al] content in the molten steel is relatively high, the boundary layer diffusion of [Al] on the molten steel side of the inclusion will not become a limiting link. At the same time, the chemical reaction at the interface is usually relatively fast, so the limiting link of the reaction process may be the mass transfer of SiO2 or Al2O3 in the inclusion particles. Assuming that the rate-controlling link of the reaction is the diffusion of SiO2 inside the inclusion, its mass transfer rate is:

[0082]

[0083] Among them, (% SiO2) inc is the mass fraction of SiO2 in inclusions at different times t; is the mass fraction of SiO2 on the molten steel-inclusion interface; A is the contact area between inclusion and molten steel, m 2 ; V is the volume of inclusions, m 3 ; is the diffusion coefficient of SiO2 in inclusions, m / s. Integrating Equation 7 yields:

[0084]

[0085] Substitute the experimental results into formula 9 and perform linear fitting. Similarly, fit the diffusion coefficient of Al2O3 in inclusions. The fitting results of the diffusion coefficients of SiO2 and Al2O3 in inclusions are as follows: Figure 9 、 Figure 10 and Figure 11 As shown in the figure, the experiment found that the logarithmic value of the change of SiO2 content in inclusions in different groups of experiments was linearly related to the reaction time, indicating that the limiting factor of inclusions was the diffusion coefficient of SiO2 in the inclusions. The calculated diffusion coefficients were 6.38×10 -8 m·s -1 , 7.13×10 -8 m·s -1 and 8.38×10 -8 m·s -1 The results differ significantly from the values ​​in previous literature. Since the Al-SiO2 reduction reaction is an exothermic reaction, during the high-temperature experiment, as the temperature rises, the steel near the inclusion particles begins to melt first. However, the contact area between the molten steel and the inclusions is small at this time, which leads to a relatively small calculated diffusion coefficient of SiO2 in the inclusion particles. Therefore, this experimental method is not suitable for studying the mass transfer coefficient of the molten steel-inclusion particle exothermic reaction.

[0086] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A new method for measuring the diffusion coefficient of a substance in inclusions in steel, characterized in that: The following steps are involved: Acquiring experimental materials and pre-treating the experimental materials; wherein the experimental materials include steel samples and inclusions; The pre-treated experimental materials were subjected to high-temperature modification experiments using a high-temperature confocal instrument, and the inclusion composition at different times was analyzed based on the experimental data. Obtain the initial conditions of the kinetic model and estimate the mass transfer coefficient of inclusions based on the initial conditions and inclusion composition analysis; The initial conditions of the kinetic model include the density and volume of the inclusion particles. The density of the inclusion particles is calculated based on the relationship between the molar volume of the oxide and temperature using the following formula: ； ； Where, is the density of liquid slag, kg·m -3 ; is the mass percentage of different oxides in the slag, wt%; is the density of different oxides in the slag, kg·m -3 ; is the molar mass of different oxides in the slag, kg·mol -1 ; is the molar volume of different oxides in the slag, m 3 ·mol -1 ; The volume calculation formula of inclusion particles is as follows: ； V is the volume of liquid inclusion particles, m -3 ; R is the radius of the liquid inclusion particles after being flattened on the surface of the steel sample, m; is the contact angle between liquid inclusion particles and solid steel.

2. The novel method for measuring the diffusion coefficient of a substance in inclusions in steel according to claim 1, characterized in that: The process of pre-treating the steel sample includes: After cutting the steel sample into several cylinders of the same preset size, the steel sample is cold mounted using UV glue; the prepared steel sample is polished and cleaned step by step; after polishing, it is placed in a container filled with alcohol for ultrasonic cleaning.

3. The novel method for measuring the diffusion coefficient of a substance in inclusions in steel according to claim 2, characterized in that: The preset dimensions include height and diameter, with the height ranging from 3-5 mm and the diameter ranging from 5-10 mm.

4. The novel method for measuring the diffusion coefficient of a substance in inclusions in steel according to claim 1, characterized in that: The process of pre-treating the inclusions includes: Slag containing the ingredients required for the experiment is obtained and ground and mixed to obtain powdered preheated slag; the powdered preheated slag is pressed into round cakes of a preset size, the round cakes are heated to prepare pre-melted slag, and the pre-melted slag is crushed and selected to screen out inclusion particles that meet size conditions; wherein the preset size conditions include the size and the error of each group of inclusion particles, the size is 100-300μm, and the error between the sizes of each group of inclusion particles does not exceed 40μm.

5. The novel method for measuring the diffusion coefficient of a substance in inclusions in steel according to claim 4, characterized in that: When heating to prepare pre-melted slag, the holding temperature must be controlled 50-100 degrees higher than the slag complete melting temperature. o C, and control the insulation time at 20~30 minutes.

6. The novel method for measuring the diffusion coefficient of a substance in inclusions in steel according to claim 1, characterized in that: The high-temperature modification experiment is carried out on the pre-treated experimental material using a high-temperature confocal device. The process of analyzing the inclusion composition at different times based on the experimental data includes: The reaction time corresponding to each group of inclusion particles is obtained through preliminary experiments. Based on the reaction time, a high-temperature modification experiment is performed on the pretreated experimental material. When the reaction time is reached, helium is filled into the heating furnace to cool it down. The experimental material is taken out after the experiment, and the composition of the inclusion particles is analyzed using a scanning electron microscope to obtain the inclusion composition. The cooling rate is controlled at 300-1000 o C.

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