Phase analysis method for oxide scale on surface of hot rolled steel

Abstract

The invention relates to a phase analysis method for oxide scale on the surface of hot rolled steel, and belongs to the technical field of physical property inspection of metal materials. The method comprises the following steps: stripping oxide scale on the surface of a hot rolled steel sample to obtain oxide scale fragments of which the surfaces are attached with iron matrix layers; grinding the iron oxide scale fragments with the iron matrix layers attached to the surfaces to obtain an iron oxide scale powder sample; and detecting the oxide scale powder sample by using an X-ray diffraction method so as to realize phase analysis of the oxide scale on the surface of the hot rolled steel. According to the invention, the iron scale is peeled off by utilizing the hardness difference between the iron scale and the matrix, and then is prepared into uniform powder with a certain particle size by adopting a grinding mode, so that the problems that the blocky iron scale is distributed layer by layer, the X-ray intensity is influenced by the absorption of an outer phase, and the diffraction data of an inner phase is distorted and the diffraction precision is high are solved. The phase analysis accuracy of the oxide scale on the surface of the hot rolled steel is improved.

Description

Technical Field

[0001] This application relates to the technical field of physical property inspection of metal materials, and particularly to a method for phase analysis of mill scale on the surface of hot-rolled steel. Background Art

[0002] Mill scale generally consists of two to three phases among Fe2O3, Fe3O4, and FeO. A certain thickness of mill scale on the surface of steel not only affects the surface quality of the steel plate but also has an adverse impact on the comprehensive performance of the product. In order to better prevent and remove mill scale and further improve product quality, in-depth phase analysis is required to provide a theoretical basis for on-site technicians to better improve the production process.

[0003] Currently, scanning electron microscopy analysis (SEM) and X-ray diffraction analysis (XRD) are usually used for phase analysis of mill scale. There are certain difficulties in sample preparation for SEM analysis. The mill scale is very brittle, and the outer layer of mill scale is easily ground. Especially when it contains a small amount of Fe2O3 phase, due to the indistinguishable gray scale values between Fe2O3 and Fe2O3, the phase composition is easily misjudged. The existing XRD analysis mainly focuses on phase analysis of bulk mill scale samples. Its disadvantage is that the bulk mill scale is distributed in layers, and the X-ray intensity is affected by the absorption of the outer layer phase, resulting in distorted diffraction data of the inner layer phase. Due to the different thicknesses of mill scale for different steel grades under different processes, the thicker mill scale can reach 40 - 50 microns. Usually, the XRD targets equipped in laboratories and production sites are copper targets or cobalt targets. Since the mass attenuation coefficients of the same phase for different targets are different, the X-ray penetration depth is different. Especially, the penetration depth of the copper target for iron and its oxides is relatively shallow, and the penetration depth during detection cannot reach the entire thickness of the mill scale, resulting in information loss. In addition, preferred orientation is likely to occur in the bulk samples during heat treatment or rolling, causing abnormal diffraction intensity. Therefore, how to accurately characterize the phase composition of mill scale on the steel plate surface is a problem that needs to be solved urgently. Summary of the Invention

[0004] This application provides a method for phase analysis of mill scale on the surface of hot-rolled steel to solve the following technical problem: how to improve the accuracy of phase analysis of mill scale on the surface of hot-rolled steel.

[0005] In the first aspect, this application provides a method for phase analysis of mill scale on the surface of hot-rolled steel, and the method includes:

[0006] Peel off the mill scale on the surface of the hot-rolled steel sample to obtain mill scale fragments with an iron matrix layer attached to the surface;

[0007] Grind the mill scale fragments with an iron matrix layer attached to the surface to obtain a mill scale powder sample;

[0008] The iron scale powder sample is detected by X-ray diffraction to realize the phase analysis of the iron scale on the surface of the hot-rolled steel.

[0009] Optionally, the peeling speed includes 150 r / min to 180 r / min.

[0010] Optionally, the grinding time is 3 minutes to 15 minutes.

[0011] Optionally, the particle size of the iron scale powder is 200 mesh to 320 mesh.

[0012] Optionally, the size of the iron scale fragments with an attached iron matrix layer on the surface is greater than 0 and not greater than 10 mm.

[0013] Optionally, the process parameters of the detection include: the scanning range 2θ is 10 degrees to 110 degrees, the scanning step size is 0.02 degrees to 0.03 degrees, and the scanning dwell time is 0.3 seconds / step to 0.5 seconds / step.

[0014] Optionally, the weight of the iron scale powder sample is not less than 5 g.

[0015] Optionally, the length of the hot-rolled steel specimen is ≤200 mm, the width is ≤60 mm, and the thickness is ≤30 mm.

[0016] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0017] The method for phase analysis of the iron scale on the surface of the hot-rolled steel provided by the embodiment of the present application includes: peeling the iron scale on the surface of the hot-rolled steel specimen to obtain iron scale fragments with an attached iron matrix layer on the surface; grinding the iron scale fragments with an attached iron matrix layer on the surface to obtain an iron scale powder sample; detecting the iron scale powder sample by X-ray diffraction to realize the phase analysis of the iron scale on the surface of the hot-rolled steel. Peeling the iron scale on the surface of the hot-rolled steel specimen to obtain iron scale fragments with an attached iron matrix layer on the surface can ensure that complete iron scale can be obtained, thereby improving the accuracy of subsequent phase analysis of the iron scale; grinding the iron scale fragments with an attached iron matrix layer on the surface makes the iron scale fragments in a powder form, thereby realizing the accuracy and sensitivity of subsequent testing of the iron scale powder sample by X-ray diffraction. The uniformity of the powder solves the problem that the blocky iron scale is distributed in layers, the X-ray intensity is affected by the absorption of the outer layer phase, and the diffraction data of the inner layer phase is distorted. It avoids the wrong phase analysis results caused by different incident depths of X-rays on the iron scale due to different target materials, and at the same time eliminates the abnormal diffraction intensity caused by the preferred orientation of the blocky sample to a certain extent. Therefore, the accuracy of the phase analysis of the iron scale on the surface of the hot-rolled steel is improved. Description of the Drawings

[0018] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application.

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the accompanying drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic flow diagram of a method for analyzing the phases of mill scale on the surface of hot-rolled steel provided by an embodiment of this application;

[0021] Figure 2 It is the thickness of mill scale measured by scanning electron microscopy for Q355B steel provided by Embodiment 1 and Comparative Example 1 of this application;

[0022] Figure 3 It is a phase detection diagram of a bulk sample of Q355B steel tested under a Co target by XRD for Comparative Example 1 of this application;

[0023] Figure 4 It is a phase detection diagram of a bulk sample of Q355B steel tested under a Cu target by XRD for Comparative Example 1 of this application;

[0024] Figure 5 It is a phase detection diagram of a powder sample after pulverizing the mill scale of Q355B steel tested under a Co target by XRD for Embodiment 1 of this application;

[0025] Figure 6 It is a phase detection diagram of a powder sample after pulverizing the mill scale of Q355B steel tested under a Cu target by XRD for Embodiment 1 of this application. Detailed implementation manners

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some but not all of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts fall within the scope of protection of this application.

[0027] The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within that range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0028] In the present application, unless otherwise stated, the orientation terms such as "upper" and "lower" specifically refer to the drawing direction in the drawings. Additionally, in the description of the specification of the present application, the terms "including", "comprising", etc. mean "including but not limited to".

[0029] Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment, etc. used in the present application can be obtained through market purchases or can be prepared by existing methods.

[0030] Currently, for the phase analysis of mill scale, scanning electron microscopy analysis (SEM) and X-ray diffraction analysis (XRD) are usually adopted. There are certain difficulties in sample preparation for SEM analysis. The iron sheet is very brittle, and the outer layer of the iron sheet is easily ground. Especially when it contains a small amount of Fe2O3 phase, due to the indistinguishable gray scale values between Fe2O3 and Fe2O3, the phase composition is prone to misjudgment. The existing XRD analysis mainly focuses on the phase analysis of massive mill scale samples. Its disadvantage is that the massive mill scale is distributed in layers, and the X-ray intensity is affected by the absorption of the outer layer phase, resulting in the distortion of the diffraction data of the inner layer phase. Due to the different thicknesses of mill scale of different steel grades under different processes, the thicker mill scale can reach 40 - 50 microns. Usually, the XRD targets equipped in laboratories and production sites are copper targets or cobalt targets. Since the mass attenuation coefficients of the same phase for different targets are different, the incident depth of X-rays is different. Especially, the penetration depth of the copper target for iron and its oxides is relatively shallow, and the penetration depth during detection cannot reach the entire thickness of the iron sheet, resulting in information loss. Additionally, the massive samples are prone to preferred orientation during heat treatment or rolling, causing abnormal diffraction intensity. Therefore, how to accurately characterize the phase composition of the mill scale on the steel plate surface is a problem that urgently needs to be solved. Therefore, in the first aspect, the present application provides a method for phase analysis of mill scale on the surface of hot-rolled steel, Figure 1 is a schematic flow chart of a method for phase analysis of mill scale on the surface of hot-rolled steel provided by an embodiment of the present application; please refer to Figure 1 , the method includes:

[0031] S1. Strip the scale on the surface of the hot-rolled steel sample to obtain scale fragments with an iron matrix layer attached to the surface.

[0032] In some embodiments, the length of the hot-rolled steel sample is ≤200 mm, the width is ≤60 mm, and the thickness is ≤30 mm.

[0033] In some embodiments, the size of the scale fragments with an iron matrix layer attached to the surface is greater than 0 and not greater than 10 mm.

[0034] In the embodiments of the present application, the length of the hot-rolled steel sample can be ≤200 mm, the width can be ≤60 mm, and the thickness can be ≤30 mm, which is convenient for sample preparation. The size of the scale fragments with an iron matrix layer attached to the surface can be greater than 0 and not greater than 10 mm, which can ensure the uniformity of subsequent grinding of the scale fragments. Exemplarily, the size of the above-mentioned scale fragments with an iron matrix layer attached to the surface can be 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, etc.

[0035] In some embodiments, the stripping speed includes 150 r / min to 180 r / min.

[0036] In the embodiments of the present application, an appropriate stripping speed can ensure that the scale is effectively removed, while not causing excessive damage to the surface of the hot-rolled steel, and at the same time preventing the scale fragments from splashing.

[0037] Exemplarily, S1 specifically includes: cutting the sample into appropriate block-shaped samples by wire cutting; completely stripping the scale on the block-shaped sample with a universal tool milling machine, and controlling the rotation speed at 160 r / min to obtain scale fragments. The stripped fragments need to have an iron matrix layer to ensure that all the scale is obtained.

[0038] S2. Grind the scale fragments with an iron matrix layer attached to the surface to obtain a scale powder sample.

[0039] In some embodiments, the grinding time is 3 minutes to 15 minutes.

[0040] In the embodiments of the present application, by utilizing the difference in hardness between the mill scale and the iron matrix, the peeled mill scale fragments are placed into a sealed sample preparation pulverizer for grinding. After grinding, the sample is sieved using a laboratory standard sieve to obtain mill scale powder. A suitable grinding time can generally further reduce the particle size and improve the fineness of grinding. At the same time, a longer grinding time also helps to make the particles more uniform and improve the shape and surface properties of the mill scale particles. The grinding time can be 3 minutes to 15 minutes. However, if the grinding time is longer than 15 minutes, it may lead to over-grinding, wasting energy and time, and may increase the equipment wear and maintenance costs; if the grinding time is shorter than 3 minutes, too short a grinding time may not achieve the required grinding effect, with larger and non-uniform particle sizes. Exemplarily, the above grinding time can be 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 15 minutes, etc. Exemplarily, the peeled mill scale fragments are collected and placed into a sealed sample preparation pulverizer for grinding, and the grinding is carried out in an intermittent manner.

[0041] In some embodiments, the particle size of the mill scale powder is 200 mesh to 320 mesh.

[0042] In the embodiments of the present application, mesh number is a unit used to represent the size of powder particles. 200 mesh means there are 200 sieve holes on a sieve mesh with a length of one inch, and 320 mesh means there are 320 sieve holes on a sieve mesh with a length of one inch. The higher the mesh number, the smaller the sieve holes, and the finer the corresponding powder particles. The particle size of the mill scale powder can be 200 mesh to 320 mesh. The mill scale powder particles are relatively small and uniform, can present different crystal planes of the crystal, the distribution of the particles in space is random, and they have a large specific surface area, which can enable the mill scale powder to fully contact with X-rays, thereby improving the accuracy and sensitivity of the test. Exemplarily, the particle size of the mill scale powder can be 200 mesh, 210 mesh, 220 mesh, 230 mesh, 240 mesh, 250 mesh, 260 mesh, 270 mesh, 280 mesh, 290 mesh, 300 mesh, 310 mesh, 320 mesh, etc.

[0043] S3. Use X-ray diffraction method to detect the mill scale powder sample to achieve the phase analysis of the mill scale on the surface of the hot-rolled steel.

[0044] In some embodiments, the process parameters of the detection include: the scanning range 2θ is 10 degrees to 110 degrees, the scanning step size is 0.02 degrees to 0.03 degrees, and the scanning dwell time is 0.3 seconds / step to 0.5 seconds / step.

[0045] In the embodiments of the present application, X-ray diffraction is a commonly used method for phase analysis. It determines the phase composition and crystal structure of a sample by measuring the diffraction angle and intensity of X-rays in the sample. X-ray diffraction has high resolution and accuracy, and can accurately determine the phase composition and crystal structure of mill scale. The mill scale powder after mixing is prepared into a sample using a sample holder. After the sample is loaded on the sample holder, the test parameters are set to perform sample testing, and qualitative and quantitative phase analysis is performed on the obtained spectrum to obtain the results. The process parameters for X-ray diffraction detection can include: the scanning range 2θ is from 10 degrees to 110 degrees, the scanning step size is from 0.02 degrees to 0.03 degrees, and the scanning dwell time is from 0.3 seconds / step to 0.5 seconds / step. The range of 10 degrees to 110 degrees can include some basic structure information at low angles and more complex crystal structure characteristic peaks at medium and high angles. At a step size of 0.02 degrees to 0.03 degrees, the details of the diffraction peaks can be captured more precisely, especially for those cases where the peak shape is narrow and the distance between adjacent peaks is close; the scanning dwell time determines the length of time for the detector to receive the X-ray signal at each scanning angle; a dwell time of 0.3 seconds / step to 0.5 seconds / step can usually ensure the signal intensity while reducing the influence of noise and improving the stability of the data. Therefore, accurate and reliable test results can be obtained under the action of the above process parameters for X-ray diffraction detection. Exemplarily, the above scanning range 2θ can be 10 degrees to 110 degrees, 20 degrees to 105 degrees, 20 degrees to 110 degrees, etc.; the scanning step size can be 0.02 degrees, 0.025 degrees, 0.03 degrees, etc.; the scanning dwell time can be 0.3 seconds / step, 0.4 seconds / step, 0.5 seconds / step, etc.

[0046] In addition, the above phase analysis can use the PDF standard diffraction database index for retrieval to determine the phase composition; during quantitative analysis, the information of Fe is removed, and the reference intensity ratio (RIR) method is used to give the relative content of each phase in the mill scale.

[0047] In some embodiments, the weight of the mill scale powder sample is not less than 5 g.

[0048] In the embodiments of the present application, the weight of the mill scale powder sample is not less than 5 g, meeting the sample preparation requirements and avoiding test errors caused by insufficient sample amount. Exemplarily, the weight of the above mill scale powder sample can be 5 g, 6 g, 7 g, 8 g, 9 g, 10 g, etc.

[0049] In summary, the present application provides a method for phase analysis of mill scale on the surface of hot-rolled steel, with the following advantages:

[0050] 1. Scale stripping: By stripping the scale on the surface of the hot-rolled steel sample, scale fragments attached with the iron matrix layer on the surface are obtained. The main purpose of doing this is to ensure obtaining a complete scale sample and avoid inaccurate phase analysis results caused by incomplete scale in subsequent analysis. The presence of the iron matrix layer can provide certain support and stability for the scale, preventing the scale from breaking or deforming during the stripping process, thus ensuring the integrity of the scale. A complete scale sample can more accurately reflect the true phase composition of the scale on the surface of the hot-rolled steel. If the scale is incomplete during the stripping process, some important phase information may be lost, affecting the accuracy of phase analysis. For example, if there are multiple layers in the scale, an incomplete sample may only contain the phases of some layers, leading to incorrect judgment of the overall scale phase.

[0051] 2. Scale grinding: Grind the scale fragments attached with the iron matrix layer to obtain a scale powder sample. The purpose of grinding is to make the scale fragments in powder form, increase the surface area of the scale, and improve the accuracy and sensitivity of subsequent X-ray diffraction testing. The powdered scale sample is more easily penetrated by X-rays, thereby increasing the penetration depth of X-rays into the scale powder sample and avoiding distortion of the diffraction data of the inner layer of the scale. The powdered scale sample can be more evenly distributed on the test sample stage, reducing the test error caused by sample unevenness. At the same time, the powdered sample can interact better with X-rays, generating a clearer diffraction pattern and improving the accuracy of phase analysis. The larger surface area of the powdered sample can absorb more X-rays, thus improving the sensitivity of the test. The scale usually has a multi-layer structure, and the phases of the inner layer may be different from those of the outer layer. If the scale sample is not in powder form, X-rays may not be able to penetrate to the inner layer, resulting in distortion of the diffraction data of the inner layer. However, the powdered sample can make X-rays penetrate the entire sample more evenly, avoiding distortion of the diffraction data of the inner layer and improving the accuracy of phase analysis.

[0052] 3. X-ray diffraction detection: Use X-ray diffraction to detect the scale powder sample to achieve phase analysis of the scale on the surface of the hot-rolled steel. X-ray diffraction is a commonly used phase analysis method. It determines the phase composition and crystal structure of the sample by measuring the diffraction angle and intensity of X-rays in the sample. X-ray diffraction has high resolution and accuracy and can accurately determine the phase composition and crystal structure of the scale. By detecting the scale powder sample, more detailed phase information can be obtained, improving the accuracy of phase analysis. At the same time, X-ray diffraction can also detect trace phases and phases with weak diffraction signals, which is very helpful for studying the complex phase composition of the scale.

[0053] Therefore, by peeling, grinding, and detecting the scale on the surface of hot-rolled steel specimens using X-ray diffraction, the accuracy of phase analysis of the scale on the surface of hot-rolled steel can be improved.

[0054] The following will further elaborate on this application in combination with specific embodiments. It should be understood that these embodiments are only used to illustrate this application and not to limit the scope of this application. For the experimental methods without specific conditions noted in the following embodiments, they are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0055] The equipment used in Comparative Example 1 and Example 1 includes a universal tool milling machine model X8130, a sealed sample preparation pulverizer model GJ-1Y, an X-ray diffractometer model Bruker D8 Advance, and EVA data processing software.

[0056] Comparative Example 1

[0057] Prepare a wire-cut Q355B hot-rolled steel block sample of 20mm×15mm×8mm. Figure 2 The scale thickness of Q355B steel provided in Example 1 and Comparative Example 1 of this application was measured by scanning electron microscopy; please refer to Figure 2 , indicating that the average scale thickness of the Q355B steel cross-section is about 45 microns by scanning electron microscopy. First, use the existing XRD phase analysis method to directly detect it with different target materials. Figure 3 This is the phase detection diagram of the Q355B steel block sample tested under the Co target of the XRD test provided in Comparative Example 1 of this application; Figure 4 This is the phase detection diagram of the Q355B steel block sample tested under the Cu target of the XRD test provided in Comparative Example 1 of this application; please refer to Figures 3 - 4 . Table 1 shows the phase analysis results of the scale with different target materials in Comparative Example 1; please refer to Table 1.

[0058] Table 1 Phase analysis results of the scale with different target materials

[0059]

[0060] From Figure 2 , Figure 3 and the data in Table 1, it can be seen that when the block samples are tested with different target materials, due to the different penetration depths of X-rays, for the same sample, the phase analysis results are different. Figure 2 It shows that for the phase of the Q355B steel block sample tested under the Co target, the Fe phase is detected, indicating that the penetration depth of X-rays can reach the entire scale thickness, and complete scale phase information can be obtained. Figure 3It shows that for the bulk sample of Q355B steel tested under the Cu target, there is no signal of the Fe matrix, indicating that the X-ray penetration depth of the Cu target for the mill scale is relatively shallow, and the complete information of the mill scale cannot be obtained.

[0061] Example 1

[0062] The mill scale of Q355B steel identical to that of Comparative Example 1 was pulverized, and the pulverized mill scale was subjected to XRD scanning detection, and the phase analysis was performed on the scanning pattern. Specifically, it includes:

[0063] Sampling, cutting a sample of 150 mm×60 mm×8 mm by wire cutting, stripping the mill scale of the cut sample with a universal tool milling machine, setting the milling speed at 160 r / min to avoid the splashing of broken pieces due to too high speed, and obtaining the size of the mill scale broken pieces of about 5 mm×2 mm×1 mm. The stripped mill scale broken pieces were collected and put into a sealed sample preparation pulverizer for grinding. The grinding was carried out in an intermittent manner to avoid overheating of the equipment. The total grinding time was 10 min, and the mesh number of the sample after grinding was 200 mesh. Screening was carried out with a 200-mesh laboratory standard sieve to obtain the mill scale powder.

[0064] The obtained mill scale powder was mixed evenly, and a certain amount of the powder was made into a sample on a sample holder. After the sample was installed on the sample holder, different targets were used respectively, and the phase test parameters were set: (1) The X-ray tube used a cobalt target, the detection voltage was 35 KV, the current was 40 mA, the scanning range of 2θ was 20 degrees to 105 degrees, the scanning step was 0.03 degrees, the scanning dwell time was 0.5 seconds / step, and the sample test was started. Figure 5 It is the phase detection diagram of the powder sample after pulverizing the mill scale of Q355B steel provided in Example 1 of this application; please refer to Figure 5 . (2) The X-ray tube used a copper target, the detection voltage was 40 KV, the current was 40 mA, the scanning range of 2θ was 20 degrees to 105 degrees, the scanning step was 0.03 degrees, the scanning dwell time was 0.5 seconds / step, and the sample test was started. Figure 6 It is the phase detection diagram of the powder sample after pulverizing the mill scale of Q355B steel provided in Example 1 of this application; please refer to Figure 6 . According to the test diffraction pattern, data analysis and processing were carried out. Since only the mill scale information is required during phase analysis, the Fe information can be removed during result processing. After removing the Fe information, the phase test data results of the mill scale in Example 1 are shown in Table 2.

[0065] Table 2 Phase analysis results after pulverizing the mill scale

[0066]

[0067] Table 3 Comparison results of the phase diffraction intensity and the diffraction standard pattern before and after pulverizing the mill scale

[0068]

[0069]

[0070] From Figures 5 - 6 As can be seen from Tables 2 to 3, compared with Comparative Example 1, the method provided in Example 1 can obtain the information of each phase of the iron sheet layer, and the measurement of each phase data is more accurate. However, the phase data (Fe2O3 and FeO) of Comparative Example 1 (Co target) is inaccurate due to the absorption effect and orientation effect of the outer phase of the massive iron sheet. Therefore, the powdered iron sheet in the embodiment of the present application avoids the absorption effect and orientation effect of the outer phase of the massive iron sheet, and the result is more accurate and reliable. Moreover, the powdered iron sheet can be unrestricted by the target material, and the phase identification is the same for different target materials, and the quantitative deviation is not large. As can be seen from Table 3, the intensity of the Fe3O4 diffraction pattern after powder making is not much different from the intensity of the standard database card pattern, and the preferred orientation is eliminated to a certain extent. The method provided in Example 1 can obtain the information of each phase of the iron sheet layer, solves the diffraction depth limitation of different target materials, and avoids the absorption effect and orientation effect of the outer phase, and the result is more accurate and reliable.

[0071] One or more technical solutions in the embodiments of the present application at least further have the following technical effects or advantages:

[0072] (1) By utilizing the difference in hardness between the scale and the substrate, after peeling off the iron sheet, it is ground into uniform powder with a certain particle size, which solves the problem that the massive scale is distributed in layers, and the X-ray intensity is affected by the absorption of the outer phase, resulting in the distortion of the diffraction data of the inner phase; it avoids the problem that when the thickness of the massive scale is too thick and the target material selection is limited, the penetration depth during detection cannot reach the entire thickness of the iron sheet, causing information loss; it solves the problem that the preferred orientation of the massive sample causes abnormal diffraction intensity;

[0073] (2) The method for analyzing the phases of the scale on the surface of the hot-rolled steel provided in the present application can accurately obtain the phase information of the scale on the surfaces of different steel plates, which is more scientific and reasonable than the existing detection means.

[0074] The above are only specific implementation manners of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for phase analysis of iron oxide scale on the surface of hot-rolled steel, characterized in that: The method comprises: The iron oxide scale on the surface of the hot-rolled steel sample is peeled off to obtain the iron oxide scale fragments with the iron matrix layer attached to the surface; Grinding the iron oxide scale fragments with the iron matrix layer attached to the surface to obtain an iron oxide scale powder sample; The iron oxide scale powder sample is tested by X-ray diffraction method to achieve phase analysis of the iron oxide scale on the surface of the hot-rolled steel.

2. The method according to claim 1, characterized in that The peeling speed ranges from 150 r / min to 180 r / min.

3. The method according to claim 1, characterized in that The grinding time is 3 minutes to 15 minutes.

4. The method according to claim 1, characterized in that: The particle size of the iron oxide scale powder is 200-320 meshes.

5. The method according to claim 1, characterized in that The size of the iron oxide scale fragments attached to the surface of the iron matrix layer is greater than 0 and not greater than 10 mm.

6. The method according to claim 1, characterized in that The process parameters of the detection include: a scanning range 2θ of 10 degrees to 110 degrees, a scanning step length of 0.02 degrees to 0.03 degrees, and a scanning dwell time of 0.3 seconds per step to 0.5 seconds per step.

7. The method according to claim 1, characterized in that The weight of the iron oxide scale powder sample is not less than 5g.

8. The method according to claim 1, characterized in that: The hot-rolled steel sample has a length of ≤200 mm, a width of ≤60 mm, and a thickness of ≤30 mm.

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