Method for detecting aluminum nitride inclusion particulate matters in steel

Abstract

The invention relates to the technical field of detection of particles mingled in steel. Specifically, the invention relates to a method for detecting aluminum nitride inclusion particles in steel. The method comprises the step of detecting by using an inclusion particulate matter analysis system comprising a scanning electron microscope (SEM) and an energy dispersive spectrometer (EDS), wherein element types collected by the energy dispersive spectrometer comprise an oxygen element. According to the scanned data, the aluminum nitride inclusion particles in the steel can be more accurately screened out, the aluminum oxide inclusion particles which are not easy to distinguish in the prior art are eliminated, the screening result is high in accuracy and efficiency, and the form, the number, the size, the size distribution and the like of the aluminum nitride inclusion particles in the steel can be visually and clearly analyzed from the detection result.

Description

Technical Field

[0001] This invention relates to the technical field of detecting particulate inclusions in steel. Specifically, this invention relates to a method for detecting aluminum nitride particulate inclusions in steel. Background Technology

[0002] In the field of steel materials, aluminum nitride (AlN) is a key non-metallic inclusion that significantly affects the properties of steel. The morphology, quantity, size, and size distribution of AlN inclusions directly influence the mechanical properties, corrosion resistance, and processing performance of steel. Controlling AlN inclusions is particularly important in certain specialty steels. However, current methods for detecting AlN inclusions in steel face numerous challenges.

[0003] While traditional metallographic microscopy can visually display the morphology and distribution of inclusion particles, it lacks the ability to directly analyze the chemical composition of materials. Moreover, due to its resolution limitations, even when combined with other compositional analysis instruments (such as energy dispersive spectroscopy (EDS), it is often difficult to accurately identify small-sized aluminum nitride inclusion particles.

[0004] Scanning electron microscopy (SEM), as a high-resolution microscopic analysis tool, can clearly observe the morphology and size of inclusion particles. SEM analysis for the compositional analysis of inclusion particles usually requires combination with analytical instruments such as electrochemical spectrometry (EDS). However, since inclusions in steel are primarily oxides and sulfides, adding oxygen (O) during EDS analysis significantly reduces the display of other element content, potentially affecting the identification of inclusion types (e.g., magnesium oxide, silicon oxide, magnesium aluminum spinel, etc.). Furthermore, nitrogen (N) is a light element, and EDS cannot perform quantitative analysis, only qualitative analysis. Therefore, conventional SEM+EDS methods do not include oxygen and nitrogen. However, when detecting aluminum nitride inclusions in steel, the aforementioned conventional SEM+EDS method cannot distinguish between alumina and aluminum nitride based on the scanning results, thus failing to accurately detect aluminum nitride inclusions.

[0005] Therefore, existing technologies for detecting aluminum nitride inclusions in steel require an efficient, accurate, and reproducible detection method to achieve comprehensive analysis of the morphology, quantity, size, size distribution, and composition of aluminum nitride inclusions, providing strong support for performance optimization and process improvement of steel materials. Summary of the Invention

[0006] Purpose of the invention

[0007] In view of the problems existing in the prior art described in the background section above, the object of the present invention is to provide a method for detecting aluminum nitride inclusions in steel.

[0008] Technical solution

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] Option 1: A method for detecting aluminum nitride inclusions in steel, wherein the method includes the following steps:

[0011] Step 1: Prepare a metallographic sample of the steel to be tested, and place the sample in the sample chamber of the scanning electron microscope in an inclusion particulate matter analysis system that includes a scanning electron microscope and an energy dispersive spectroscopy instrument.

[0012] Step 2: Set the detection parameters of the scanning electron microscope (SEM) to distinguish between the matrix and inclusion particles in the metallographic sample.

[0013] Step 3: Set the operating parameters of the scanning electron microscope (SEM) and the energy dispersive spectrometer (EDS), including the scanning area of ​​the SEM on the metallographic sample, the scanning resolution of the SEM, the minimum size of the inclusion particles scanned by the SEM, the data acquisition time of the EDS, and the types of elements acquired by the EDS, wherein the types of elements include oxygen.

[0014] Step 4: The metallographic sample of steel is scanned by scanning electron microscope in the inclusion particle analysis system to identify the morphology, quantity, size and size distribution of inclusion particles. Then, the elemental content range of the identified inclusion particles is detected by energy dispersive spectroscopy.

[0015] Step 5: Analyze the detection results obtained from Step 4 and screen for aluminum nitride inclusions.

[0016] Option 2: The method for detecting aluminum nitride inclusions in steel according to Option 1 above, wherein in step 1, the preparation of the metallographic sample of the steel to be tested includes preparing the metallographic sample of the steel to be tested according to the Chinese national standard GB / T13298 "Metallic Microstructure Examination Method".

[0017] Option 3: The method for detecting aluminum nitride inclusions in steel according to Option 1 or 2 above, wherein in step 1, the metallographic sample is a cylindrical metallographic sample with a diameter in the range of about 25 to about 35 mm and a height in the range of about 10 to about 20 mm.

[0018] Option 4: A method for detecting aluminum nitride inclusions in steel according to any one of Options 1 to 3 above, wherein step 2 includes providing an aluminum conductive adhesive as a reference material in a non-detection area of ​​the metallographic sample, and setting grayscale thresholds for the aluminum conductive adhesive, the substrate, and the inclusions, wherein the grayscale threshold of the substrate is set in the range of 195 to 205, the grayscale threshold of the aluminum conductive adhesive is set in the range of 55 to 65, and the grayscale threshold of the inclusions is set in the range of 0 to 160 (±5), so that the grayscale of the observed inclusions is lower than that of the substrate, thereby achieving the distinction between the substrate and the inclusions of the metallographic sample.

[0019] Option 5: A method for detecting aluminum nitride inclusions in steel according to any one of Options 1 to 4 above, wherein in step 3, the area of ​​the scanning region is set to approximately 150 to approximately 170 mm². 2 .

[0020] Option 6: A method for detecting aluminum nitride inclusions in steel according to any one of Options 1 to 5 above, wherein in step 3, the scanning resolution of the scanning electron microscope is set to 512×512px (pixels), and when inclusions are detected, the scanning resolution is set to 1024×1024px.

[0021] Scheme 7: A method for detecting aluminum nitride inclusions in steel according to any one of Schemes 1 to 6 above, wherein in step 3, the minimum inclusion size scanned by the scanning electron microscope is set to ≥1 micrometer.

[0022] Option 8: A method for detecting aluminum nitride inclusions in steel according to any one of Options 1 to 7 above, wherein in step 3, the data acquisition time of the energy dispersive spectrometer is set to a range of 0.1 to 0.3 seconds.

[0023] Scheme 9: A method for detecting aluminum nitride inclusions in steel according to any one of Schemes 1 to 8 above, characterized in that, in step 3, the types of elements collected by the energy dispersive spectrometer include Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Ni, Nb, Mo and O.

[0024] Scheme 10: A method for detecting aluminum nitride inclusions in steel according to any one of Schemes 1 to 9 above, wherein in step 5, the screening includes screening from the detected inclusions for inclusions with an aluminum content of about ≥80% by mass, preferably about ≥85% by mass, and more preferably about ≥90% by mass as the aluminum nitride inclusions.

[0025] Technical effect

[0026] The method for detecting aluminum nitride inclusions in steel provided by this invention includes using an inclusion particle analysis system comprising a scanning electron microscope (SEM) and an energy dispersive spectroscopy (EDS). Based on the scanned data, aluminum nitride inclusions in steel can be screened more accurately and directly, eliminating alumina inclusions that are difficult to distinguish in the prior art. The screening results are highly accurate and efficient, and the morphology, quantity, size, and size distribution of aluminum nitride inclusions in steel can be clearly and intuitively observed from the detection results.

[0027] The detection method of this invention can not only directly identify real aluminum nitride inclusions on metallographic samples, but also detect their specific quantity and size distribution, which provides strong support for the performance optimization and process improvement of steel materials. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments 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 from these drawings without creative effort.

[0029] Figure 1 In Embodiment 1 of the present invention, SEM images (a) of alumina inclusion particles taken by SEM in the SEM+EDS inclusion particle analysis system and elemental composition distribution map (b) of alumina inclusion particles obtained by EDS are provided. In this embodiment, the elements collected by EDS include not only conventional elements but also oxygen.

[0030] Figure 2 In Embodiment 1 of the present invention, SEM images (a) of aluminum nitride inclusion particles taken by SEM in the SEM+EDS inclusion particle analysis system and elemental composition distribution map (b) of aluminum nitride inclusion particles obtained by EDS are provided. In addition to conventional elements, oxygen is also included in the elements collected by EDS.

[0031] Figure 3 In Comparative Example 1 of this invention, SEM images (a) of alumina inclusion particles taken by SEM in the SEM+EDS inclusion particle analysis system and elemental composition distribution map (b) of alumina inclusion particles obtained by EDS are provided. The EDS is set to collect only conventional elements and does not include oxygen.

[0032] Figure 4In Comparative Example 1 of this invention, SEM images (a) of aluminum nitride inclusions were taken using the SEM in the SEM+EDS inclusion particle analysis system, and elemental composition distribution maps (b) of aluminum nitride inclusions were obtained by EDS. The EDS was set to collect only conventional elements and did not include oxygen. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely for the purpose of aiding understanding of this invention and should not be considered as specific limitations on this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. Process parameters in the following embodiments that are not specifically specified are generally performed under conventional conditions.

[0034] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. The term "about" as used in this invention indicates that the number it modifies may fluctuate within ±20%, ±15%, ±10%, ±5%, or ±2% of that number. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0035] According to the present invention, a method for detecting aluminum nitride inclusions in steel is provided, the method comprising the steps 1 to 5.

[0036] Step 1 includes preparing a metallographic sample of the steel to be tested and placing the sample in the sample chamber of the scanning electron microscope in an inclusion particulate matter analysis system that includes a scanning electron microscope and an energy dispersive spectroscopy (EDS) spectrometer.

[0037] In this invention, the scanning electron microscope (SEM) includes any type of SEM commonly used in the art; however, in some preferred embodiments, the SEM of this invention includes an SEM with a resolution of less than about 10 nm, such as a conventional SEM with a resolution in the range of about 1 to about 10 nm, or a field emission SEM with a higher resolution (less than about 1 nm). Using an SEM with a resolution greater than about 10 nm may result in missed detections due to excessively low resolution.

[0038] In a preferred embodiment of step 1, the preparation of the metallographic specimen of the steel to be tested may include preparing the metallographic specimen of the steel to be tested according to the Chinese national standard GB / T13298 "Metallic Microstructure Examination Method".

[0039] In step 1, there are no particular requirements for the shape of the metallographic specimen prepared. However, in some preferred exemplary embodiments of the present invention, the metallographic specimen can generally be a cylindrical metallographic specimen. The diameter of the cylinder can be in the range of about 25 to about 35 mm, for example, about 30 mm; and the height can be in the range of about 10 to about 20 mm, for example, about 15 mm.

[0040] Step 2 includes setting the detection parameters of the scanning electron microscope and using the scanning electron microscope to distinguish between the matrix and inclusion particles in the metallographic sample.

[0041] In a preferred exemplary embodiment of step 2, in order to distinguish between the matrix and inclusion particles in the metallographic sample, step 2 may specifically include providing an aluminum conductive adhesive as a reference material in the non-detection area of ​​the metallographic sample, and setting grayscale thresholds for the aluminum conductive adhesive, the matrix, and the inclusion particles, so that the grayscale of the observed inclusion particles is lower than that of the matrix, thereby achieving the distinction between the matrix and inclusion particles of the metallographic sample.

[0042] In some exemplary embodiments, the grayscale threshold of the substrate can be set in the range of 195 to 205, for example, 200; the grayscale threshold of the aluminum conductive adhesive can be set in the range of 55 to 65, for example, 60; and the grayscale threshold of the impurity particles can be set in the range of 0 to 160 (±5), for example, 0 to 155, 0 to 160, or 0 to 165, preferably 0 to 160.

[0043] Step 3 includes setting the operating parameters of the scanning electron microscope (SEM) and the energy dispersive spectrometer (EDS), including the scanning area of ​​the SEM on the metallographic sample, the scanning resolution of the SEM, the minimum size of the inclusion particles scanned by the SEM, the data acquisition time of the EDS, and the types of elements acquired by the EDS, wherein the types of elements include oxygen.

[0044] In step 3, the scanning area of ​​the scanning electron microscope on the metallographic sample is not particularly limited, but in some preferred exemplary embodiments of the present invention, the scanning area is set to be between about 150 and about 170 mm². 2 Within the range, for example, set to approximately 160mm 2 .

[0045] In step 3, the scanning resolution of the scanning electron microscope is generally not limited. For example, under normal circumstances, the scanning resolution of the scanning electron microscope can be set to 512×512px. However, when particulate matter is detected, the scanning resolution can be increased and set to 1024×1024px.

[0046] In step 3, the minimum size of the inclusion particles scanned by the scanning electron microscope can be adjusted as needed. In some preferred exemplary embodiments of the present invention, the minimum size of the inclusion particles scanned by the scanning electron microscope can be set to ≥1 micrometer. Here, if the size is set to less than 1 micrometer, on the one hand, current sample preparation technology is difficult to achieve such a low standard; on the other hand, the size is too small, making it difficult for the scanning electron microscope to identify, and the detection of particles that are too small is not very meaningful for practical applications and will greatly increase the workload of detection.

[0047] In step 3, the data acquisition time of the energy dispersive spectrometer is generally not limited. However, in some preferred exemplary embodiments of the present invention, the data acquisition time of the energy dispersive spectrometer can be set in the range of about 0.1 to about 0.3 seconds. An acquisition time that is too long, for example, exceeding about 0.3 seconds, may result in an excessively long detection time; an acquisition time that is too short, for example, less than about 0.1 seconds, may result in inaccurate elemental content detection.

[0048] In step 3, the types of elements collected by the energy dispersive spectrometer include not only commonly detected elements such as sodium (Na), magnesium (Mg), aluminum (Al), silicon (Si), sulfur (S), chlorine (Cl), potassium (K), calcium (Ca), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), nickel (Ni), niobium (Nb), and molybdenum (Mo), but also oxygen (O).

[0049] In the steel samples of this invention, the inclusion particles formed by element Al are generally only aluminum nitride (AlN) and aluminum oxide (Al2O3). Currently, there is no good method for distinguishing between them in the prior art. Since nitrogen is a light element, energy dispersive spectroscopy (EDS) cannot perform quantitative analysis, only qualitative analysis. Therefore, in this invention, the types of elements collected by EDS can include oxygen, thereby identifying Al2O3 and thus determining the AlN inclusion particles.

[0050] Although EDS is less accurate than elements with atomic numbers greater than 11 for quantitative analysis of light element O, in this invention, where only AlN and Al2O3 inclusion particles need to be detected, EDS is still reliable and usable for detecting O compared to N.

[0051] Step 4 includes scanning the metallographic sample of steel with a scanning electron microscope in the inclusion particle analysis system to identify the morphology, quantity, size and size distribution of inclusion particles, and then detecting the elemental content range of the identified inclusion particles with an energy dispersive spectrometer.

[0052] Step 5 includes analyzing the detection results obtained from step 4 and screening for aluminum nitride inclusions.

[0053] In some preferred embodiments of step 5, the screening includes selecting from the detected inclusions an aluminum content of about ≥80% by mass, preferably about ≥85% by mass, and more preferably about ≥90% by mass as the aluminum nitride inclusions. Here, the standard for the aluminum content should not be lower than about 80% by mass; otherwise, some alumina composite inclusions may be identified as aluminum nitride, thus causing inclusions containing a higher proportion of alumina to be identified as aluminum nitride inclusions.

[0054] The present invention will now be described in further detail with reference to specific embodiments and comparative examples.

[0055] The particulate matter analysis system used in the following examples and comparative examples is the Particle X model particulate matter analysis system from Phine Scientific Instruments Ltd., wherein the scanning electron microscope has a resolution of 10 nm.

[0056] A steel grade containing aluminum nitride and alumina inclusions produced by a steel mill was provided. Cylindrical metallographic specimens of the steel grade were prepared by grinding according to the Chinese national standard GB / T13298 "Metallic Microstructure Examination Methods". The diameter of the cylindrical metallographic specimens was approximately 30 mm, and the height was approximately 15 mm. The inclusions in the metallographic specimens were imaged using a high-resolution field emission scanning electron microscope (FE-SEM), and one aluminum nitride inclusion and one alumina inclusion were accurately identified by EDS as the detection objects in the following examples and comparative examples.

[0057] Example 1: Detection of particulate matter inclusions in the steel grade.

[0058] Step 1: Place the metallographic sample in the sample chamber of the scanning electron microscope (SEM) of the Particle X system, which includes a scanning electron microscope and an energy dispersive spectroscopy (EDS) instrument.

[0059] Step 2: Aluminum conductive adhesive, used as a reference material, is pasted onto the non-detection area of ​​the metallographic sample. The detection parameters of the scanning electron microscope are set, specifically including setting the gray threshold of the substrate to 200, the gray threshold of the aluminum conductive adhesive to 60, and the gray threshold of the inclusion particles to be in the range of 0 to 160.

[0060] Step 3: Set the scanning area of ​​the scanning electron microscope on the metallographic sample to approximately 160 mm². 2 The scanning resolution of the scanning electron microscope (SEM) is set to 512×512px, and when particulate matter is detected, the scanning resolution is increased to 1024×1024px; the minimum particulate matter size scanned by the SEM is set to be greater than 1 micrometer; the data acquisition time of the energy dispersive spectrometer (EDS) is set to 0.3 seconds; the common elements collected by the EDS are set to include Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Ni, Nb, Mo, and O.

[0061] Step 4: Start the inclusion particle analysis system to identify the morphology, quantity, size and size distribution of inclusion particles in the metallographic sample. Then, use the energy dispersive spectrometer to detect the elemental content range of the identified inclusion particles. After the scan is completed, export the detection result data.

[0062] Step 5: Obtain the test results and perform screening of aluminum nitride inclusions, including screening out inclusions with an aluminum content of about 85% by weight from the detected inclusions as aluminum nitride inclusions.

[0063] In Example 1 above, since oxygen was added as one of the elements collected by the energy dispersive spectroscopy (EDS), the alumina inclusions (such as those identified by FE-SEM above) were... Figure 1 The aluminum content in (a) is much lower than 85% by weight (as shown in the image). Figure 1 (b) shows that aluminum nitride inclusions (as shown above, determined by FE-SEM) are... Figure 2 The aluminum content in (a) is higher than 85% by weight (as shown in the figure). Figure 2 (b) As shown. Therefore, the particles with an aluminum content ≥85% detected in Example 1 can be identified as aluminum nitride inclusions. The size distribution statistics of aluminum nitride inclusions with an aluminum content higher than 85% by weight detected in Example 1 are shown in Table 1 below.

[0064] Table 1:

[0065]

[0066] Comparative Example 1:

[0067] The inclusions in the steel were detected using a process similar to that in Example 1, except that in step 3, the energy dispersive spectrometer was set to collect only the conventional elements Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Ni, Nb and Mo, without adding O.

[0068] In Comparative Example 1 above, since oxygen was not included as one of the elements collected by the energy dispersive spectroscopy (EDS), the alumina inclusions (such as those identified by FE-SEM above) were not included. Figure 3 The aluminum content in (a) is higher than 85% by weight (as shown in the figure). Figure 3 (b) shows that aluminum nitride inclusions (as shown above, determined by FE-SEM) are... Figure 4 The aluminum content in (a) will also be higher than 85% by weight (as shown in the example). Figure 4 (b) is shown.

[0069] In this case, particles with an aluminum content of about 85% or more were screened from the detected inclusions. Some of the alumina inclusions, since no O was added to the elements collected by the energy dispersive spectrometer, also had an aluminum content of about 85% by mass or more. Therefore, the screened inclusions included both aluminum nitride inclusions and alumina inclusions. The statistical results of the size distribution of the inclusions are shown in Table 2 below.

[0070] Table 2:

[0071]

[0072] By comparing the experimental results in Tables 1 and 2 above, it can be seen that when O element is added to the elements collected by the energy dispersive spectrometer, the particle size of different particles with an aluminum content of about 85% or more is reduced to varying degrees. This indicates that the alumina inclusion particles have been eliminated, and the remaining statistical data are the actual data of aluminum nitride inclusion particles. Moreover, important data such as the morphology, quantity, size and size distribution of aluminum nitride inclusion particles can be obtained at the same time.

[0073] 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 therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions claimed by the present invention.

Claims

1. A method for detecting aluminum nitride inclusions in steel, characterized in that, The method includes the following steps: Step 1: Prepare a metallographic sample of the steel to be tested, and place the sample in the sample chamber of the scanning electron microscope in an inclusion particulate matter analysis system that includes a scanning electron microscope and an energy dispersive spectroscopy instrument. Step 2: Set the detection parameters of the scanning electron microscope (SEM) to distinguish between the matrix and inclusion particles in the metallographic sample. Step 3: Set the operating parameters of the scanning electron microscope (SEM) and the energy dispersive spectrometer (EDS), including the scanning area of ​​the SEM on the metallographic sample, the scanning resolution of the SEM, the minimum size of the inclusion particles scanned by the SEM, the data acquisition time of the EDS, and the types of elements acquired by the EDS, wherein the types of elements include oxygen. Step 4: The metallographic sample of steel is scanned by scanning electron microscope in the inclusion particle analysis system to identify the morphology, quantity, size and size distribution of inclusion particles. Then, the elemental content range of the identified inclusion particles is detected by energy dispersive spectroscopy. Step 5: Analyze the detection results obtained from Step 4 and screen for aluminum nitride inclusions.

2. The method for detecting aluminum nitride inclusions in steel according to claim 1, characterized in that, In step 1, the preparation of the metallographic specimen of the steel to be tested includes preparing the metallographic specimen of the steel to be tested according to the Chinese national standard GB / T13298 "Methods for Examination of Microstructure of Metals".

3. The method for detecting aluminum nitride inclusions in steel according to claim 1, characterized in that, In step 1, the metallographic specimen is a cylindrical metallographic specimen with a diameter in the range of 25 to 35 mm and a height in the range of 10 to 20 mm.

4. The method for detecting aluminum nitride inclusions in steel according to claim 1, characterized in that, Step 2 includes providing an aluminum conductive adhesive as a reference material in the non-detection area of ​​the metallographic sample, and setting grayscale thresholds for the aluminum conductive adhesive, the substrate, and the inclusion particles. The grayscale threshold of the substrate is set in the range of 195 to 205, the grayscale threshold of the aluminum conductive adhesive is set in the range of 55 to 65, and the grayscale threshold of the inclusion particles is set in the range of 0 to 160 (±5), so that the grayscale of the observed inclusion particles is lower than that of the substrate, thereby achieving the distinction between the substrate and the inclusion particles of the metallographic sample.

5. The method for detecting aluminum nitride inclusions in steel according to claim 1, characterized in that, In step 3, the area of ​​the scanning region is set to 150 to 170 mm². 2 .

6. The method for detecting aluminum nitride inclusions in steel according to claim 1, characterized in that, In step 3, the scanning resolution of the scanning electron microscope is set to 512×512px, and when particulate matter is detected, the scanning resolution is set to 1024×1024px.

7. The method for detecting aluminum nitride inclusions in steel according to claim 1, characterized in that, In step 3, the minimum size of the inclusion particles scanned by the scanning electron microscope is set to ≥1 micrometer.

8. The method for detecting aluminum nitride inclusions in steel according to claim 1, characterized in that, In step 3, the data acquisition time of the energy spectrometer is set to be in the range of 0.1 to 0.3 seconds.

9. The method for detecting aluminum nitride inclusions in steel according to claim 1, characterized in that, In step 3, the types of elements collected by the energy dispersive spectrometer include Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Ni, Nb, Mo, and O.

10. The method for detecting aluminum nitride inclusions in steel according to any one of claims 1 to 9, characterized in that, In step 5, the screening includes selecting from the detected inclusion particles an aluminum content of ≥80% by mass, preferably ≥85% by mass, and more preferably ≥90% by mass as the aluminum nitride inclusion particles.

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