Quality detection device and method for steel vanadium-nitrogen alloy product

Abstract

The invention relates to the technical field of vanadium-nitrogen alloy quality detection, in particular to a quality detection device and method for a steel vanadium-nitrogen alloy product, and the method comprises the following steps: S1, adopting a scanning electron microscope to carry out microstructure observation on grinding surfaces of a vanadium-nitrogen alloy sample in transverse and longitudinal directions, and judging the quality of the vanadium-nitrogen alloy sample on the microstructure level; s2, a scanning electron microscope and an X-ray energy disperse spectroscopy are adopted to calculate the proportion of the number of pure V point locations to the number of total detection point locations, and the quality of the vanadium-nitrogen alloy sample is further judged on the microscopic component level; and S3, detecting and calculating the effective nitrogen content by adopting a nitrogen-oxygen combined measuring instrument, and finally judging the quality of the vanadium-nitrogen alloy sample. According to the method, the comprehensiveness and accuracy of quality identification of the vanadium-nitrogen alloy can be remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of vanadium-nitrogen alloy quality testing technology, specifically to a quality testing device and method for vanadium-nitrogen alloy steel products. Background Technology

[0002] While the production processes of different vanadium-nitrogen alloy manufacturers are largely similar, various factors such as raw material ratios, temperature, production process, and production time significantly impact the conversion rate and quality of vanadium-nitrogen alloys. Some manufacturers, prioritizing cost savings and accelerating production, produce vanadium-nitrogen alloys of inconsistent quality. Compared to vanadium-titanium products, vanadium-nitrogen alloys offer more effective strengthening and grain refinement, with stable vanadium and nitrogen yields and minimal fluctuations in steel performance. In steel production, the use of vanadium-nitrogen alloys, besides the grain refinement effect of vanadium, significantly enhances strength through the formation of vanadium carbonitride phases in the steel matrix. The precipitation and pinning effect of these phases significantly improves yield strength.

[0003] Currently, the nitrogen conversion rate in vanadium-nitrogen alloy processes at steel companies is generally calculated and designed based on 70%. However, with the increasing number of vanadium-nitrogen alloy manufacturers, many steel companies are failing to achieve a 70% conversion rate, and even with a 50% conversion rate, the yield strength of the steel still falls short. The quality of vanadium-nitrogen alloys has become a Damocles' sword hanging over steel companies.

[0004] Existing analytical methods for vanadium-nitrogen alloys are primarily based on GB / T 20567, "Vanadium-Nitrogen Alloys." This standard provides analytical methods for vanadium, nitrogen, carbon, phosphorus, sulfur, oxygen, silicon, manganese, and aluminum in vanadium-nitrogen alloys. The determination of nitrogen is specified in the "Determination of Nitrogen in Vanadium-Nitrogen Alloys by Thermal Conductivity Cell Method." This standard meets routine testing requirements under normal circumstances. However, for vanadium-nitrogen alloys from different manufacturers and of different quality grades, the test results only show the total nitrogen content, which cannot truly determine the actual quality of the vanadium-nitrogen alloy and cannot accurately reflect its overall quality. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a quality testing device and method for vanadium-nitrogen alloy steel products, used to accurately test the quality of vanadium-nitrogen alloy products.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] On the one hand, a quality inspection method for vanadium-nitrogen alloy steel products is proposed, including:

[0008] S1. Use a scanning electron microscope to observe the microstructure of the polished surfaces of the vanadium-nitrogen alloy sample in both the transverse and longitudinal directions; if the microstructure of the sample is a uniform granular dispersed structure, proceed to step S2; if the microstructure of the sample is a non-uniform agglomerated structure, the vanadium-nitrogen alloy is determined to be substandard.

[0009] S2. Using a scanning electron microscope and an X-ray energy dispersive spectroscopy (EDS) instrument, multi-point component detection is performed on the sample determined to be a uniform granular dispersed structure in step S1. The points are uniformly distributed in the horizontal and vertical directions of the sample. The ratio of the number of pure V points to the total number of detected points is calculated. If the ratio is greater than or equal to a preset value, proceed to step S3. If the ratio is less than the preset value, the vanadium-nitrogen alloy quality is substandard.

[0010] S3. Using a nitrogen-oxygen combined analyzer, the effective nitrogen content of samples whose ratio of the number of pure V points determined in step S2 to the total number of detection points is greater than or equal to a preset value is measured. The effective nitrogen content is calculated. If the effective nitrogen content meets the preset effective nitrogen content standard, the vanadium-nitrogen alloy is judged to meet the quality standard; if the effective nitrogen content does not meet the preset effective nitrogen content standard, the inferior vanadium-nitrogen alloy is judged to be substandard.

[0011] Furthermore, in step S1, the observation accuracy of the scanning electron microscope must be sufficient to clearly distinguish the tissue morphology at the 50μm scale of the sample grinding surface, and the preparation process of the sample grinding surfaces in the transverse and longitudinal directions must be consistent.

[0012] Furthermore, in step S2, the pure V point is a detection point that contains only V, N, and C elements or contains less than a preset amount of Fe element, and contains no or less than a preset amount of O, Al, Si, Ca, and Cl impurity elements.

[0013] Furthermore, the total number of testing points shall not be less than 60, and the number of testing points shall be evenly distributed in the horizontal and vertical directions.

[0014] Furthermore, the preset ratio of the number of pure V-points to the total number of detection points is 90%.

[0015] Further, in step S3, effective nitrogen detection: After sample processing, the sample is placed in the extraction furnace of the nitrogen-oxygen combined analyzer. Using a constant-step temperature control method, the furnace temperature is gradually increased from 1500℃ to 2300℃, and the amount of nitrogen precipitation in each temperature range is recorded. Based on the abrupt change in nitrogen precipitation, the melting and boiling point range of the vanadium-nitrogen alloy is determined. Nitrogen precipitated below this range is defined as ineffective nitrogen, and nitrogen precipitated above this range is defined as effective nitrogen. The calculation formula is as follows:

[0016] Q = Q t -Q i

[0017] In the formula, Q is the effective nitrogen content, Q t Q represents the total nitrogen content. iThis represents the amount of ineffective nitrogen.

[0018] Furthermore, the electron microscope images acquired by scanning electron microscopy are preprocessed to highlight particle boundaries and agglomeration features;

[0019] Construct and train tissue structure analysis models to learn the uniform particle distribution characteristics of diffuse tissues and the blocky aggregation characteristics of compacted tissues;

[0020] During testing, the pre-processed transverse / vertical electron microscope images of the sample to be tested are input into the microstructure analysis model. The microstructure analysis model automatically outputs the results of the determination of diffuse microstructure and agglomerated microstructure. If it is agglomerated microstructure, the vanadium-nitrogen alloy is directly determined to be substandard.

[0021] Furthermore, the contents of C, N, and V elements and the total contents of impurity elements in the energy spectrum data collected by the X-ray energy spectrometer are used as characteristic variables to construct a feature matrix;

[0022] Construct and train a semi-quantitative analysis model to learn the element content patterns at purity points;

[0023] During testing, the multi-point data of the sample to be tested from the energy dispersive spectrometer are input into the semi-quantitative composition analysis model. The semi-quantitative composition analysis model automatically determines whether each point is a pure V point and calculates the ratio of the number of pure points to the total number of points in real time. If the ratio is less than the preset value, the vanadium-nitrogen alloy is directly judged to be substandard.

[0024] Furthermore, an effective nitrogen analysis model was constructed based on a regression model, and a continuous curve of temperature versus nitrogen emission was fitted to learn the curve characteristics of gradual nitrogen emission in the low-temperature range and a sharp increase in nitrogen emission in the high-temperature range.

[0025] The effective nitrogen analysis model is trained to automatically identify temperature points where the curve slope changes abruptly, and to determine the temperature ranges for ineffective nitrogen and effective nitrogen.

[0026] During testing, the effective nitrogen analysis model automatically integrates and calculates the total amount of ineffective nitrogen. Combined with the total nitrogen amount, it calculates and outputs the effective nitrogen content. If the effective nitrogen content meets the preset effective nitrogen content standard, the vanadium-nitrogen alloy is deemed to meet the quality standard; if the effective nitrogen content does not meet the preset effective nitrogen content standard, the inferior vanadium-nitrogen alloy is deemed to be substandard.

[0027] On the other hand, a quality inspection device for vanadium-nitrogen alloy steel products is proposed, comprising:

[0028] The described microstructure analysis model is used to identify the microstructure type of a sample based on electron micrographs acquired by scanning electron microscopy; and to determine the quality of vanadium-nitrogen alloys.

[0029] The aforementioned semi-quantitative composition analysis model is used to determine whether each point is a pure V point based on the energy spectrum data collected by the X-ray energy spectrometer, and to calculate the ratio of the number of pure points to the total number of points in real time; and to determine the quality of the vanadium-nitrogen alloy.

[0030] The effective nitrogen analysis model is used to automatically identify temperature points where the curve slope changes abruptly, determine the ineffective nitrogen temperature range and the effective nitrogen temperature range, calculate and output the effective nitrogen content, and determine the quality of vanadium-nitrogen alloys.

[0031] The above approach has the following beneficial effects:

[0032] 1. This method utilizes scanning electron microscopy (SEM) to analyze the microstructure of vanadium-nitrogen alloys, determining whether the microstructure is uniform and dispersed granular, thus making a preliminary judgment on the quality of the vanadium-nitrogen alloy. It then combines SEM with X-ray energy dispersive spectroscopy (EDS) for semi-quantitative microscopic analysis of the vanadium-nitrogen alloy product, obtaining the proportion of pure V sites, further assessing the quality. Finally, it uses a nitrogen-oxygen combined analyzer to detect and calculate the effective nitrogen content of the vanadium-nitrogen alloy, providing a final judgment on its quality. Compared to existing technologies, this method follows a logical chain of microstructure screening → microscopic composition quantification → effective nitrogen efficacy verification. It ensures the rationality of the alloy structure through SEM observation, quantifies the purity of pure V through EDS composition analysis, and verifies the actual functional value of the alloy through effective nitrogen determination, significantly improving the comprehensiveness and accuracy of quality identification. Furthermore, it accurately determines the suitability of parameters such as time and temperature in the nitriding process of vanadium-nitrogen alloys through microstructure analysis, laying the foundation for adjusting the vanadium-nitrogen alloy production process.

[0033] The quality testing of vanadium-nitrogen alloys using this technical solution plays a crucial role in the smelting and rolling production of steel using the vanadium-nitrogen alloy process. Detecting the quality of vanadium-nitrogen alloys can significantly improve the strength of steel products and reduce the smelting and rolling production costs of steel using the vanadium-nitrogen alloy process.

[0034] 2. This solution proposes a method for quality determination and analysis of vanadium-nitrogen alloys based on available nitrogen, and provides an accurate method for measuring available nitrogen in vanadium-nitrogen alloys. By accurately measuring available nitrogen in vanadium-nitrogen alloys, the quality of the alloys can be judged. This method can be used to guide the process control of vanadium-nitrogen alloy production, thereby improving the quality of vanadium-nitrogen alloy products. When using vanadium-nitrogen alloy production processes for steel production, it effectively and steadily improves the mechanical properties of steel products, ensuring the quality of construction steel, buildings, bridges, and engineering projects, while also saving costs and reducing resource consumption. Attached Figure Description

[0035] Figure 1 This is a flowchart of a method according to an embodiment of the present invention.

[0036] Figure 2 This is a structural diagram of the device module according to an embodiment of the present invention.

[0037] Figure 3 The images shown are vertical / horizontal electron microscope images of sample 1 from an embodiment of the present invention.

[0038] Figure 4 The images shown are vertical / horizontal electron microscope images of sample 2 from an embodiment of the present invention.

[0039] Figure 5 The images shown are vertical / horizontal electron microscope images of sample 3 from an embodiment of the present invention.

[0040] Figure 6 The images shown are vertical / horizontal electron microscope images of sample 4 from an embodiment of the present invention.

[0041] Figure 7 The images shown are vertical / horizontal electron microscope images of sample 5 from an embodiment of the present invention.

[0042] Figure 8 This is a schematic diagram of the energy spectrum annotation of the longitudinal structure of sample 1 in an embodiment of the present invention.

[0043] Figure 9 These are schematic diagrams 1-4 of the longitudinal tissue of sample 1 in an embodiment of the present invention.

[0044] Figure 10 The diagrams 5-8 are schematic diagrams of the longitudinal structure of sample 1 in an embodiment of the present invention.

[0045] Figure 11 This is a schematic diagram of the energy spectrum annotation of the transverse structure of sample 1 in an embodiment of the present invention.

[0046] Figure 12 The diagrams 9-11 are schematic diagrams of the transverse structure of sample 1 in an embodiment of the present invention.

[0047] Figure 13 This is a schematic diagram of the energy spectrum annotation of the longitudinal structure of sample 5 in an embodiment of the present invention.

[0048] Figure 14 These are schematic diagrams 51-52 of the longitudinal tissue of sample 5 in an embodiment of the present invention.

[0049] Figure 15 These are schematic diagrams 53-55 of the longitudinal tissue of sample 5 in an embodiment of the present invention.

[0050] Figure 16 This is a schematic diagram of the energy spectrum annotation of the transverse structure of sample 5 in an embodiment of the present invention.

[0051] Figure 17 The diagrams 56-57 are schematic diagrams of the transverse structure of sample 5 in an embodiment of the present invention.

[0052] Figure 18The diagrams 58-60 are schematic diagrams of the transverse structure of sample 5 in an embodiment of the present invention.

[0053] Figure 19 This is a schematic diagram showing the nitrogen precipitation values ​​of various samples at different temperatures in an embodiment of the present invention. Detailed Implementation

[0054] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] The following detailed description illustrates the specific implementation method:

[0056] like Figure 1 As shown: Quality inspection methods for vanadium-nitrogen alloy steel products.

[0057] S1. The microstructure of the vanadium-nitrogen alloy sample's polished surfaces in both the transverse and longitudinal directions is observed using a scanning electron microscope (SEM). If the sample's microstructure is a uniform granular, dispersed structure, proceed to step S2. If the sample's microstructure is a non-uniform, agglomerated structure, the vanadium-nitrogen alloy is deemed substandard. In this embodiment, the SEM observation accuracy must be sufficient to clearly distinguish the microstructure at a 50 μm scale on the sample's polished surfaces, and the preparation process of the polished surfaces in both the transverse and longitudinal directions must be consistent.

[0058] S2. Using scanning electron microscopy and X-ray energy dispersive spectroscopy, multi-point compositional analysis is performed on the sample identified as having a uniform granular dispersion structure in step S1. The analysis points are uniformly distributed in the horizontal and vertical directions of the sample. The ratio of the number of pure V points to the total number of analysis points is calculated. If the ratio is greater than or equal to a preset value, proceed to step S3; if the ratio is less than the preset value, the vanadium-nitrogen alloy quality is substandard. In this embodiment, pure V points are analysis points containing only V, N, and C elements, or containing less than a preset amount of Fe element, and containing no or less than a preset amount of impurity elements such as O, Al, Si, Ca, and Cl. The total number of analysis points is not less than 60, and the number of analysis points is uniformly distributed in the horizontal and vertical directions. In this embodiment, the preset value for the ratio of pure V points to the total number of analysis points is 90%, that is, if the ratio of pure V points to the total number of analysis points is ≥90%, proceed to step S3 for further judgment; if the ratio of pure V points to the total number of analysis points is <90%, the vanadium-nitrogen alloy quality is determined to be substandard.

[0059] S3. Using a nitrogen-oxygen combined analyzer, samples where the ratio of the number of pure V-points determined in step S2 to the total number of detection points is greater than or equal to a preset value are tested for effective nitrogen. The effective nitrogen content is calculated. If the effective nitrogen content meets the preset effective nitrogen content standard, the vanadium-nitrogen alloy is deemed to meet the quality standard; if the effective nitrogen content does not meet the preset effective nitrogen content standard, the inferior vanadium-nitrogen alloy is deemed to be substandard. In this embodiment, the effective nitrogen detection steps are as follows:

[0060] After processing, the sample was placed in the extraction furnace of a nitrogen-oxygen combined analyzer. The furnace temperature was gradually increased from 1500℃ to 2300℃ using a constant-step temperature control method, and the amount of nitrogen precipitated in each temperature range was recorded. The melting and boiling point range of the vanadium-nitrogen alloy was determined based on the abrupt change in nitrogen precipitation. Nitrogen precipitated below this range was defined as ineffective nitrogen, and nitrogen precipitated above this range was defined as effective nitrogen. The calculation formula is as follows:

[0061] Q = Q t -Q i

[0062] In the formula, Q is the effective nitrogen content, Q t Q represents the total nitrogen content. i This represents the amount of ineffective nitrogen.

[0063] In this embodiment, the effective nitrogen content standard is typically set between 8% and 14% based on the comprehensive mechanical properties of vanadium-nitrogen alloy products, such as strength, toughness, ductility, and resistance to thermal fatigue.

[0064] In some embodiments, automated intelligent detection of vanadium-nitrogen alloy quality is performed based on the above parameters. Specifically, in the microstructure analysis section, a Convolutional Neural Network (CNN) is selected. CNN excels at extracting microscopic features from images, such as particle distribution uniformity and agglomeration degree. A microstructure analysis model is constructed based on CNN, and several transverse / vertical scanning electron microscope (SEM) images of vanadium-nitrogen alloys are collected as a training set. The SEM images are labeled according to the judgment criteria in step S1 above: positive sample - diffuse microstructure, negative sample - compacted microstructure. Image preprocessing such as size normalization and grayscale enhancement is performed on the SEM images to highlight particle boundaries and agglomeration features. The microstructure analysis model learns the uniform particle distribution characteristics of diffuse microstructure and the blocky agglomeration characteristics of compacted microstructure. Subsequently, the trained microstructure analysis model can be used to receive transverse / vertical SEM images of the sample to be inspected, automatically outputting the judgment results of diffuse microstructure and compacted microstructure. If it is compacted microstructure, the vanadium-nitrogen alloy quality is directly judged to be substandard.

[0065] For the semi-quantitative composition analysis, a supervised learning classification model, such as Support Vector Machine (SVM), Random Forest, or Lightweight Neural Network, is selected. Supervised learning classification models excel at classifying based on multiple features (elemental content). A semi-quantitative composition analysis model is constructed based on this model, and energy dispersive spectral data (EDS) of 60 points on a vanadium-nitrogen alloy are collected as the training set, including the contents of elements such as C, N, V, O, Al, Si, and Fe. The EDS data are labeled according to the judgment criteria in step S2 above. The C, N, and V elemental contents and the total impurity element content in the EDS data are used as feature variables to construct a feature matrix. The semi-quantitative composition analysis model learns the elemental content patterns of pure points. Subsequently, the trained semi-quantitative composition analysis model can be used to receive EDS data from the sample to be tested, automatically determine whether each point is a pure V point, and continuously calculate the ratio of the number of pure points to the total number of points. If the ratio is less than 90%, the vanadium-nitrogen alloy is directly judged as substandard.

[0066] For the effective nitrogen analysis, regression models, such as piecewise linear regression and Long Short-Term Memory (LSTM) networks, are selected. Regression models excel at fitting continuous curves and identifying abrupt change points. An effective nitrogen analysis model is constructed based on the regression model, and temperature-nitrogen precipitation data for different vanadium-nitrogen alloys are collected as the training set. Abrupt change point temperatures in the temperature-nitrogen precipitation data are labeled according to the judgment criteria in step S3 above. The effective nitrogen analysis model learns the curve characteristics of gradual nitrogen precipitation in the low-temperature range and a sharp increase in nitrogen precipitation in the high-temperature range. Subsequently, the trained effective nitrogen analysis model can be used to receive temperature-nitrogen precipitation data from a nitrogen-oxygen analyzer, automatically integrate to calculate the total ineffective nitrogen, and combine this with the total nitrogen to calculate and output the effective nitrogen content. If the effective nitrogen content does not meet the preset effective nitrogen content standard, the inferior vanadium-nitrogen alloy is deemed substandard.

[0067] Based on the above, a quality testing device for vanadium-nitrogen alloy steel products can be constructed, consisting of a semi-quantitative composition analysis model, a semi-quantitative composition analysis model, and an available nitrogen analysis model. The modules are connected sequentially, as follows: Figure 2 As shown.

[0068] The semi-quantitative compositional analysis model is used to identify the microstructure type of the sample based on electron micrographs acquired by scanning electron microscopy and to determine the quality of vanadium-nitrogen alloys. It is also used to determine whether each point is a pure nitrogen (V) point based on energy dispersive spectroscopy (EDS) data acquired by X-ray energy dispersive spectroscopy (EDS) and to calculate the ratio of pure points to total points in real time, thus determining the quality of vanadium-nitrogen alloys. The effective nitrogen analysis model is used to automatically identify temperature points where the curve slope abruptly changes, determine the ineffective nitrogen temperature range and the effective nitrogen temperature range, and calculate and output the effective nitrogen content, thus determining the quality of vanadium-nitrogen alloys.

[0069] The feasibility of the above-mentioned vanadium-nitrogen alloy quality testing method and apparatus is verified through the following embodiments:

[0070] The microstructure of vanadium-nitrogen alloys was analyzed using the powerful magnification of a scanning electron microscope. Five vanadium-nitrogen alloy samples were selected and prepared by grinding in both horizontal and vertical directions, and their microstructures were analyzed separately.

[0071] Electron micrographs of longitudinal and transverse tissues of sample 1 are shown below. Figure 3 As shown; electron micrographs of the longitudinal and transverse tissues of sample 2 are shown below. Figure 4 As shown; electron micrographs of the longitudinal and transverse tissues of sample 3 are shown below. Figure 5 As shown; electron micrographs of the longitudinal and transverse tissues of sample 4 are shown below. Figure 6 As shown; electron micrographs of the longitudinal and transverse tissues of sample 5 are shown below. Figure 7 As shown in the electron micrographs, there are no obvious regular differences in the longitudinal and transverse microstructures of the same sample. The microstructure of high-quality vanadium-nitrogen alloys is uniform, dispersed granular, while the microstructure of low-quality vanadium-nitrogen alloys is non-uniform, agglomerated blocky.

[0072] Using a combination of scanning electron microscopy and X-ray energy dispersive spectroscopy, a semi-quantitative microscopic analysis was performed on five vanadium-nitrogen alloy samples. Energy dispersive spectroscopy analysis was conducted on 60 points in the horizontal and vertical directions of each vanadium-nitrogen alloy sample.

[0073] The energy spectrum annotation of the longitudinal tissue of sample 1 is as follows: Figure 8 As shown, the longitudinal tissue patterns of sample 1 are as follows: Patterns 1-8 Figure 9 and Figure 10 As shown; the content and statistical results of each element are shown in Table 1 and Table 2:

[0074] Table 1. Element content in the spectral diagrams of 8 groups of vanadium-nitrogen alloys.

[0075] Spectrum Labels Spectrum Figure 1 Spectrum Figure 2 Spectrum Figure 3 Spectrum Figure 4 Spectrum Figure 5 Spectrum Figure 6 Spectrum Figure 7 Spectrum Figure 8 C 8.89 6.16 6.62 6.72 5.26 3.94 5.17 11.67 N 20.00 14.42 15.82 17.28 5.23 1.74 8.43 21.09 O 13.14 6.53 22.34 36.66 Al 0.45 0.55 0.14 0.26 0.20 0.16 Si 0.35 0.31 0.21 0.20 0.16 S 0.13 0.18 0.16 Cl 0.29 0.34 0.12 K 0.21 0.21 0.12 Ca 0.15 0.31 1.34 0.25 0.21 V 70.29 61.41 77.04 74.81 76.17 51.29 40.99 63.60 Mn 0.45 0.21 Fe 0.82 3.47 0.52 0.64 5.43 17.71 7.61 3.00 Eu 0.46 Total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00

[0076] Table 2. Statistical analysis of elemental contents in 8 groups of vanadium-nitrogen alloy spectra

[0077] statistics C N O Al Si S Cl K Ca V Mn Fe Eu Maximum value 11.67 21.09 36.66 0.55 0.35 0.18 0.34 0.21 1.34 77.04 0.45 17.71 0.46 Minimum value 3.94 1.74 6.53 0.14 0.16 0.13 0.12 0.12 0.15 40.99 0.21 0.52 0.46 average 6.81 13.00 64.45 4.90 Standard deviation 2.44 7.08 12.93 5.75

[0078] The energy spectrum annotation of the transverse structure of sample 1 is as follows: Figure 11 As shown, the transverse tissue patterns of sample 1 are shown in Figures 9-11. Figure 12 As shown; the content and statistical results of each element are shown in Tables 3 and 4:

[0079] Table 3. Element content in the spectral diagrams of the three vanadium-nitrogen alloys.

[0080] Spectrum Labels Spectrum Figure 9 Spectrum Figure 10 Spectrum Figure 11 C 4.13 4.93 2.30 N 10.79 18.32 4.09 O 6.79 Al 0.20 0.17 Si 0.07 Ca 0.10 V 83.91 76.35 86.08 Fe 0.97 0.40 0.40 Total 100.00 100.00 100.00

[0081] Table 4. Statistical analysis of elemental contents in 8 groups of vanadium-nitrogen alloy spectra

[0082]

[0083]

[0084] Energy spectrum annotation of longitudinal tissue of sample 5 as follows Figure 13 As shown, the longitudinal tissue patterns 51-55 of sample 5 are as follows: Figure 14 and Figure 15 As shown; the content and statistical results of each element are shown in Tables 5 and 6:

[0085] Table 5. Element content in the spectra of the five groups of vanadium-nitrogen alloys.

[0086] Spectrum Labels Spectrum 51 Spectrum 52 Spectrum 53 Spectrum 54 Spectrum 55 C 1.73 5.43 8.83 3.59 10.30 N 10.14 21.89 22.71 17.76 15.41 O 9.88 Na 0.57 Al 0.24 Si 0.12 Cl 0.11 K 0.14 Ca 0.13 0.24 V 87.71 72.32 57.01 78.40 73.70 Fe 0.42 0.36 0.27 0.25 0.35 Total 100.00 100.00 100.00 100.00 100.00

[0087] Table 6. Statistical analysis of elemental contents in the spectra of 5 groups of vanadium-nitrogen alloys.

[0088] statistics C N O Na Al Si Cl K Ca V Fe Maximum value 10.30 22.71 9.88 0.57 0.24 0.12 0.11 0.14 0.24 87.71 0.42 Minimum value 1.73 10.14 9.88 0.57 0.24 0.12 0.11 0.14 0.13 57.01 0.25 average 5.97 17.58 73.83 0.33 Standard deviation 3.57 5.12 11.17 0.07

[0089] The energy spectrum annotation of the transverse structure of sample 5 is as follows: Figure 16 As shown, the transverse tissue patterns 51-55 of sample 5 are as follows: Figure 17 and Figure 18 As shown; the content and statistical results of each element are shown in Tables 7 and 8:

[0090] Table 7. Element content in the spectra of 5 groups of vanadium-nitrogen alloys.

[0091] Spectrum Labels Spectrum 56 Spectrum 57 Spectrum 58 Spectrum 59 Spectrum 60 C 4.79 5.49 5.98 4.96 5.47 N 10.35 24.46 24.40 21.68 24.47 V 84.86 70.05 69.62 73.35 70.06 Total 100.00 100.00 100.00 100.00 100.00

[0092] Table 8. Statistical analysis of elemental contents in five groups of vanadium-nitrogen alloy spectra.

[0093] statistics C N V Maximum value 5.98 24.47 84.86 Minimum value 4.79 10.35 69.62 average 5.34 21.07 73.59 Standard deviation 0.47 6.11 6.48

[0094] The elemental content of samples 2-4 was statistically analyzed using the same method. The summarized results are shown in Table 9.

[0095] Table 9 Summary of elemental contents of the 5 samples

[0096] sample Total locations V(CN) point Composite point V(CN) point ratio Sample 1 11 6 5 54.5％ Sample 2 16 12 5 75％ Sample 3 13 12 1 92.3％ Sample 4 9 6 3 66.7％ Sample 5 10 9 1 90％ total 60 45 15 75％

[0097] Among the 60 sites, the ratio of pure V(CnNm) to oxide inclusions and V(CnNm) composite sites was 45:15. Samples 3 and 5 had the highest ratios. Analysis revealed that the V(CnNm) matrix and trace amounts of Fe constituted the vast majority of sites in the vanadium-nitrogen alloy, while other elements exhibited isolated oxide aggregations.

[0098] Based on the above, microstructural analysis shows that vanadium-nitrogen alloys exhibit different microstructures. From the distribution and content of V(CnNm) substances, microstructural analysis of the five vanadium-nitrogen alloy samples in both horizontal and vertical directions reveals that the superior microstructure is uniform, dispersed granular, while the inferior microstructure is uneven, agglomerated, and blocky. Semi-quantitative microscopic analysis indicates that the formation of V, N, and C from the original V₂O₅ mineral concentrate through carbon reduction and nitriding under Fe catalyst conditions is clearly understood. Most of the V(CnNm) products are pure, with virtually no impurity elements present at position 60. Impurity elements exhibit aggregation, and except for heavy metals, almost all exist in oxide form. The content of bound oxygen can be used to approximate the other impurity elements.

[0099] To investigate the stability of nitrogen in vanadium-nitrogen alloys, the first step was to address the long-term stability of the alloy products. Powder samples of the vanadium-nitrogen alloys were exposed to air for 30 days, and the nitrogen aging was tested using a nitrogen-oxygen analyzer. The results are shown in Table 10.

[0100] Table 10 Results of the timeliness test of nitrogen in 30 days

[0101]

[0102] Test results show that the total nitrogen content in the vanadium-nitrogen alloy tends to stabilize within 30 days, with a maximum range of only 0.31%. In the remaining samples, multiple tests were conducted after six months and one year, and the nitrogen content showed no significant change. This indicates that the nitrogen content in the vanadium-nitrogen alloy itself does not have a significant time-dependent effect, and the time-dependent effect of nitrogen in the vanadium-nitrogen alloy can be ignored.

[0103] In addition to the aforementioned long-term aging test, the change in nitrogen content extracted at different temperatures can indicate the stability of nitrogen binding in vanadium-nitrogen alloys. Using a nitrogen-oxygen combined analyzer, the extraction furnace temperature characteristics can be adjusted. Starting from 1500℃, nine extraction furnace temperatures were set from 1500℃ to 2300℃ in 100℃ increments, with the instrument's normal temperature control at 2327℃. Nitrogen content analysis was performed on different vanadium-nitrogen alloy samples. Analysis of the experiments at each extraction temperature revealed a sudden change in nitrogen content in the vanadium-nitrogen alloy between 1700℃ and 1800℃. This indicates that the melting and boiling points of the vanadium-nitrogen alloy mixture have a general range, which was confirmed as shown in Table 11.

[0104] Table 11 Nitrogen Emission Rate at 9 Extraction Furnace Temperatures (1500℃~2300℃)

[0105] Temperature ℃ Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 1500 6.37 3.70 6.74 15.40 5.78 1600 6.48 4.34 6.64 12.46 8.05 1700 7.93 7.60 7.38 14.58 11.43 1800 12.72 12.46 12.02 13.11 12.85 1900 13.37 15.88 12.53 13.42 14.04 2000 14.79 15.24 13.29 14.59 15.20 2100 16.21 16.06 14.77 15.27 15.21 2200 16.42 16.91 15.86 16.51 15.49 2300 16.38 16.92 15.81 16.73 15.55

[0106] Reference Figure 19The figure shows an experimental diagram illustrating the extraction temperature abrupt change point on which the determination and analysis of available nitrogen in vanadium-nitrogen alloys depend. Based on this temperature abrupt change point, the available nitrogen in vanadium-nitrogen alloys can be accurately determined.

[0107] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for quality detection of a vanadium-nitrogen alloy product of steel material, characterized by, The method comprises the following steps: S1. Microstructure observation of the grinding surface of the vanadium-nitrogen alloy sample in the horizontal and vertical directions is performed by using a scanning electron microscope; If the microstructure of the sample is uniform granular dispersion structure, step S2 is entered; if the microstructure of the sample is non-uniform and compact structure, it is determined that the quality of the vanadium-nitrogen alloy is not up to standard; S2. Multi-point composition detection of the sample determined as uniform granular dispersion structure in step S1 is performed by using a scanning electron microscope and an X-ray energy spectrometer, and the points are uniformly distributed in the horizontal and vertical directions of the sample; the ratio of the number of pure V points to the total number of detected points is calculated, and if the ratio is greater than or equal to a preset value, step S3 is entered; If the ratio is less than the preset value, the quality of the vanadium-nitrogen alloy is not up to standard; S3. Effective nitrogen detection of the sample determined as the ratio of the number of pure V points to the total number of detected points being greater than or equal to the preset value in step S2 is performed by using a nitrogen-oxygen combined detector, the content of effective nitrogen is calculated, and if the content of effective nitrogen meets the preset effective nitrogen content standard, it is determined that the quality of the vanadium-nitrogen alloy is up to standard; if the content of effective nitrogen does not meet the preset effective nitrogen content standard, it is determined that the quality of the poor-quality vanadium-nitrogen alloy is not up to standard.

2. The method for quality detection of vanadium-nitrogen alloyed products of steel materials according to claim 1, characterized in that, In step S1, the observation accuracy of the scanning electron microscope needs to meet the requirement of clearly distinguishing the structure morphology under the scale of 50 μm of the grinding surface of the sample, and the preparation process of the grinding surface of the sample in the horizontal and vertical directions is consistent.

3. The method for quality detection of vanadium-nitrogen alloyed product of steel material according to claim 1, characterized in that, In step S2, the pure V point is a detected point containing only V, N and C elements or less than a preset amount of Fe element, and containing no or less than a preset amount of O, Al, Si, Ca and Cl impurity elements.

4. The method for quality inspection of vanadium-nitrogen alloyed product of steel material according to claim 1, characterized by, The total number of detected points is not less than 60, and the number of detected points in the horizontal and vertical directions is uniformly distributed.

5. The method for quality detection of vanadium-nitrogen alloyed products of steel materials according to claim 1, characterized in that, The preset value of the ratio of the number of pure V points to the total number of detected points is 90%.

6. The method for quality detection of vanadium-nitrogen alloyed products of steel materials according to claim 1, characterized in that, In step S3, effective nitrogen detection: after the sample is treated, it is placed into an extraction furnace of the nitrogen-oxygen combined detector, the temperature of the extraction furnace is gradually increased from 1500 DEG C to 2300 DEG C in an equal-step temperature control mode, and the nitrogen element precipitation amount in each temperature interval is recorded; the boiling point interval of the vanadium-nitrogen alloy is determined according to the mutation point of the nitrogen element precipitation amount, the nitrogen precipitated below the interval is defined as invalid nitrogen, and the nitrogen precipitated above the interval is defined as effective nitrogen; the calculation formula is as follows: Q = Q t - Q i wherein Q is the effective nitrogen content, Q t is the total nitrogen content, Q i is the ineffective nitrogen content.

7. The method for quality detection of vanadium-nitrogen alloyed products of steel materials according to claim 1, characterized in that, The electron microscope image collected by the scanning electron microscope is pretreated to highlight the characteristics of the grain boundaries and agglomerated blocks; An organization structure analysis model is constructed and trained to learn the uniform granular distribution characteristics of the dispersion structure and the block agglomeration characteristics of the compact structure; During detection, the pretreated horizontal / vertical direction electron microscope image of the sample to be detected is input into the organization structure analysis model, and the organization structure analysis model automatically outputs the dispersion structure and compact structure determination results, and if it is a compact structure, the quality of the vanadium-nitrogen alloy is directly determined as not up to standard.

8. The method for quality detection of vanadium-nitrogen alloyed product of steel material according to claim 1, characterized in that, The C, N and V element contents and the total impurity element content in the energy spectrum data collected by the X-ray energy spectrometer are taken as characteristic variables to construct a characteristic matrix; An element semi-quantitative analysis model is constructed and trained to learn the element content rules of the pure point; During detection, the multi-point data of the energy spectrometer of the sample to be detected is input into the element semi-quantitative analysis model, the element semi-quantitative analysis model automatically determines whether each point is a pure V point, and the ratio of the number of pure points to the total number of points is calculated in real time, and if the ratio is less than a preset value, the quality of the vanadium-nitrogen alloy is directly determined as not up to standard.

9. The method for quality detection of vanadium-nitrogen alloyed products of steel materials according to claim 1, characterized in that, Based on the regression model, an effective nitrogen analysis model is constructed to fit the continuous curve of temperature and nitrogen precipitation amount, and learn the curve characteristics of flat nitrogen precipitation in the low temperature range and sudden increase of nitrogen precipitation in the high temperature range; The effective nitrogen analysis model is trained to automatically identify the temperature point of sudden change of curve slope, determine the invalid nitrogen temperature range and the effective nitrogen temperature range, and calculate the output effective nitrogen content; During detection, the effective nitrogen analysis model automatically integrates and calculates the total amount of invalid nitrogen, combines the total amount of nitrogen, calculates the output effective nitrogen content, and determines that the quality of vanadium-nitrogen alloy meets the standard if the effective nitrogen content meets the preset effective nitrogen content standard; otherwise, the quality of the poor vanadium-nitrogen alloy does not meet the standard.

10. A device for quality detection of a vanadium-nitrogen alloy product of steel material, characterized by, It comprises: The tissue structure analysis model of claim 7 is used to identify the microstructure type of the sample based on the electron microscope image collected by the scanning electron microscope; Determine the quality of vanadium-nitrogen alloy; The component semi-quantitative analysis model of claim 8 is used to determine whether each point is a pure V point based on the energy spectrum data collected by the X-ray energy spectrometer, and to real-time statistics the ratio of the number of pure point and the total number of points; determine the quality of vanadium-nitrogen alloy; The effective nitrogen analysis model of claim 9 is used to automatically identify the temperature point of sudden change of curve slope, determine the invalid nitrogen temperature range and the effective nitrogen temperature range, and calculate the output effective nitrogen content; determine the quality of vanadium-nitrogen alloy.

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