Method for measuring austenite carbon content in steel based on X-ray diffraction method

Abstract

The invention relates to the technical field of carbon content detection, in particular to a method for measuring austenite carbon content in steel based on an X-ray diffraction method, which comprises the following steps of: performing a systematic diffraction experiment by using a quenched high-carbon steel sample to obtain a diffraction spectral line of the sample; fitting the diffraction spectral line of the sample by using a Rietveld method; calculating the lattice constant of the austenite by using the orientation diffraction angle of the austenite; and calculating the percentage content of carbon in the austenite according to the lattice constant. The method provides an efficient, accurate and convenient solution for measuring the austenite carbon content in the steel.

Description

Technical Field

[0001] This invention relates to the field of carbon content detection technology, and in particular to a method for determining the austenitic carbon content in steel based on X-ray diffraction. Background Technology

[0002] In the production and application of steel materials, the carbon content of austenite is one of the important factors affecting the performance of steel. Austenite not only determines the strength, toughness, and corrosion resistance of steel, but is also closely related to heat treatment processes and subsequent processing performance. Traditional methods for determining austenite carbon content mainly include chemical analysis, spectroscopic analysis, and thermal analysis. Although these methods can provide accurate results to a certain extent, they often have disadvantages such as complex operation, long time consumption, and high requirements for sample pretreatment.

[0003] In recent years, X-ray diffraction (XRD) has gradually become an important tool in the field of materials analysis due to its non-destructive, rapid, and accurate characteristics. By analyzing the crystal structure of materials, XRD can provide rich information about phase composition and crystal structure. For determining the carbon content of the austenitic phase in steel, XRD has great potential because it can directly extract characteristic information related to carbon content from the material's diffraction pattern.

[0004] Although some studies have attempted to determine the carbon content in steel using X-ray diffraction, certain limitations remain. For example, existing methods often require complex sample preparation and data processing procedures, and the accuracy and repeatability of the measurement results are affected by the presence of different phases. Therefore, there is a need to develop a simple, rapid, and highly accurate X-ray diffraction method for determining the austenitic carbon content in steel. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for determining the austenitic carbon content in steel using X-ray diffraction. The invention primarily utilizes the Rietveld method to fit the diffraction spectrum of the sample, calculates the lattice constant of austenite based on the orientation diffraction angle, and then calculates the percentage carbon content in austenite based on the lattice constant. This provides an efficient, accurate, and convenient solution for determining the austenitic carbon content in steel.

[0006] The technical means employed in this invention are as follows: A method for determining the austenitic carbon content in steel based on X-ray diffraction includes: conducting a systematic diffraction experiment on a quenched high-carbon steel sample to obtain the diffraction spectrum of the sample; fitting the diffraction spectrum of the sample using the Rietveld method; calculating the lattice constant of austenite using the austenite orientation diffraction angle; and calculating the percentage carbon content in austenite based on the lattice constant.

[0007] Furthermore, the Rietveld method is used to determine the structural model and the linear function. The structural model uses crystal parameters to derive the parameters required for the linear function. The entire diffraction pattern is fitted using the expression to solve for the functional form and specific parameters of the expression. The fitting formula is as follows:

[0008] in, and For the measured strength and backing strength of the curves, , , These are the first and second phases of a certain phase in the sample. The multiplicity factor, angle factor, and structural amplitude including temperature factor of the root diffraction line; It is a peak-shaped function; for The phase weighting factor, and It is related to the content of the phase.

[0009] Furthermore, the lattice constants are calculated using the Scherrer equation:

[0010] Where λ is the wavelength of the Co target. The diffraction angle is the orientation angle of austenite. , , This refers to the crystal plane index.

[0011] Further, the percentage of carbon in the austenite is calculated. :

[0012] in, for The lattice constant of the phase, This indicates the percentage of carbon in austenite.

[0013] Furthermore, the diffraction experiment was conducted using an X-ray diffractometer with a Co target, and the tube voltage and tube current were adjusted to obtain the diffraction pattern.

[0014] Compared with the prior art, the present invention has the following advantages: This invention provides a method for determining the austenitic carbon content in steel based on X-ray diffraction. The method involves performing a systematic diffraction experiment on a quenched high-carbon steel sample to obtain the sample's diffraction patterns; fitting the diffraction patterns using the Rietveld method; calculating the austenite lattice constant using the austenite orientation diffraction angle; and calculating the percentage carbon content in the austenite based on the lattice constant. This invention provides an efficient, accurate, and convenient solution for determining the austenitic carbon content in steel, improving research efficiency.

[0015] Based on the above reasons, this invention can be widely applied in fields such as carbon content detection. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of the method for determining the austenitic carbon content in steel based on X-ray diffraction in this invention.

[0018] Figure 2 This is the diffraction pattern of the sample to be tested in Example 1 of the present invention.

[0019] Figure 3 This is an image obtained by fitting the diffraction spectrum of the sample under test using the Rietveld method in Example 1 of the present invention.

[0020] Figure 4 This is the diffraction pattern of the sample to be tested in Example 2 of the present invention.

[0021] Figure 5 This is an image obtained by fitting the diffraction spectrum of the sample under test using the Rietveld method in Embodiment 2 of the present invention.

[0022] Figure 6 This is the diffraction pattern of the sample to be tested in Example 3 of the present invention.

[0023] Figure 7 This is an image obtained by fitting the diffraction spectrum of the sample under test using the Rietveld method in Example 3 of the present invention. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0027] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0028] like Figure 1 As shown, this invention provides a method for determining the austenitic carbon content in steel based on X-ray diffraction, comprising: A systematic diffraction experiment was conducted using a quenched high-carbon steel sample to obtain the diffraction pattern of the sample. In a preferred embodiment of the present invention, the diffraction experiment was conducted using an X-ray diffractometer with a Co target, and the tube voltage and tube current were adjusted to obtain the diffraction pattern.

[0029] During the experiment, an X`PERT PRO X-ray diffractometer was used with a Co target, and the tube voltage was adjusted to 35kV and the tube current was set to 40mA. A quenched high-carbon steel sample was placed in the instrument for systematic diffraction experiments to obtain clear diffraction lines.

[0030] Using HighScorePlus software, the diffraction patterns of the sample were obtained to determine the phase composition. The Rietveld method was then used to fit the diffraction patterns. In a preferred embodiment of this invention, the Rietveld method was used to determine the structural model and linear function. The structural model was used to derive the parameters required for the linear function from the crystal parameters. The entire diffraction pattern was fitted using the expression, and the functional form and specific parameters of the expression were solved. The fitting formula is as follows:

[0031] in, and For the measured strength and backing strength of the curves, , , These are the first and second phases of a certain phase in the sample. The multiplicity factor, angle factor, and structural amplitude including temperature factor of the root diffraction line; It is a peak-shaped function; for The phase weighting factor, and It is related to the content of the phase.

[0032] The lattice constant of austenite is calculated using the austenite orientation diffraction angle; in a preferred embodiment of the invention, the lattice constant is calculated using the Scherrer equation.

[0033] Where λ is the wavelength of the Co target. The diffraction angle is the orientation angle of austenite. , , This refers to the crystal plane index.

[0034] The percentage of carbon in austenite is calculated based on the lattice constant. Specifically, in a preferred embodiment of this invention, the percentage of carbon in austenite is calculated. :

[0035] in, for The lattice constant of the phase, This indicates the percentage of carbon in austenite.

[0036] Example 1 In this embodiment, a high-carbon steel sample with a pure austenitic structure was selected as sample 0, and machined to dimensions of 20 mm in length, 20 mm in width, and 5 mm in height. The selected experimental parameters were: an X'PERT PRO X-ray diffractometer was used, a Co target was employed, and the tube voltage was adjusted to 35 kV, with the tube current set to 40 mA. The sample was placed in the instrument, and a systematic diffraction experiment was conducted to obtain clear diffraction lines.

[0037] Using HighscorePlus software, the diffraction patterns of the sample were obtained, determining that the sample was composed of... Composition as Figure 2 As shown, the obtained diffraction lines were fitted using the Rietveld refinement method. Figure 3 As shown, we obtain (200) Orientation diffraction angle The angle is 29.66375°, and the Scherrer equation is used as follows:

[0038] In the formula, λ is the wavelength of the Co target, which is 0.17902 nm. The lattice constant α of the austenite is calculated to be 0.4949 nm.

[0039] Finally, the percentage of carbon in austenite is calculated using the following formula:

[0040] In the formula, =0.3573nm, which is the lattice constant of the pure γ phase, and x represents the percentage of carbon in the austenite.

[0041] Therefore, the carbon content of austenite in sample 0 is 0.42%.

[0042] The carbon content of the Olympic body was measured to be 0.44% using a PDA-8000 spark direct-reading spectrometer, with an error of only 5%.

[0043] Example 2 In this embodiment, a sample made of quenched high-carbon steel was selected as sample 1, machined to dimensions of 20 mm in length, 20 mm in width, and 5 mm in height. The selected experimental parameters were: an X'PERT PRO X-ray diffractometer was used, a Co target was employed, and the tube voltage was adjusted to 35 kV, with the tube current set to 40 mA. The quenched high-carbon steel sample was placed in the instrument, and a systematic diffraction experiment was conducted to obtain clear diffraction lines.

[0044] Using HighscorePlus software, the diffraction patterns of the sample were obtained, determining that the sample consisted of α-Fe and... Composition as Figure 4As shown, the obtained diffraction lines were fitted using the Rietveld refinement method. Figure 5 As shown, we obtain (200) Orientation diffraction angle The angle is 29.8919°, and the Scherrer equation is used as follows:

[0045] In the formula, λ is the wavelength of the Co target, which is 0.17902 nm. The lattice constant a of the austenite is calculated to be 0.3592 nm.

[0046] Finally, the percentage of carbon in austenite is calculated using the following formula:

[0047] In the formula, =0.3573nm, which is the lattice constant of the pure γ phase, and x represents the percentage of carbon in the austenite.

[0048] Therefore, the austenite carbon content of quenched high-carbon steel sample 1 is 0.57%.

[0049] Example 3 In this embodiment, a sample made of quenched high-carbon steel was selected as sample 2, machined to dimensions of 20 mm in length, 20 mm in width, and 5 mm in height. The selected experimental parameters were: an X'PERT PRO X-ray diffractometer was used, a Co target was employed, and the tube voltage was adjusted to 35 kV, with the tube current set to 40 mA. The quenched high-carbon steel sample was placed in the instrument, and a systematic diffraction experiment was conducted to obtain clear diffraction lines.

[0050] Using HighscorePlus software, the diffraction patterns of the sample were obtained, determining that the sample consisted of α-Fe and... Composition as Figure 6 As shown, the obtained diffraction lines were fitted using the Rietveld refinement method. Figure 7 As shown, we obtain (200) Orientation diffraction angle The angle is 29.9240°, and the Scherrer equation is used as follows:

[0051] In the formula, λ is the wavelength of the Co target, which is 0.17902 nm. The lattice constant α of the austenite is calculated to be 0.3588 nm.

[0052] Finally, the percentage of carbon in austenite is calculated using the following formula:

[0053] In the formula, =0.3573nm, which is the lattice constant of the pure γ phase, and x represents the percentage of carbon in the austenite.

[0054] Therefore, the carbon content of austenite in quenched high-carbon steel sample 2 is 0.46%.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the austenitic carbon content in steel based on X-ray diffraction, characterized in that, include: A systematic diffraction experiment was conducted using quenched high-carbon steel samples to obtain the diffraction patterns of the samples. The diffraction patterns of the sample were fitted using the Rietveld method; The lattice constant of austenite is calculated using the orientation diffraction angle of austenite. The percentage of carbon in austenite is calculated based on the lattice constant.

2. The method for determining the austenitic carbon content in steel based on X-ray diffraction according to claim 1, characterized in that, The Rietveld method is used to determine the structural model and linear function. The structural model uses crystal parameters to derive the parameters required for the linear function. The entire diffraction pattern is fitted using the expression, and the functional form and specific parameters of the expression are solved. The fitting formula is as follows: in, and For the measured strength and backing strength of the curves, , , These are the first and second phases of a certain phase in the sample. The multiplicity factor, angle factor, and structural amplitude including temperature factor of the root diffraction line; It is a peak-shaped function; for The phase weighting factor, and It is related to the content of the phase.

3. The method for determining the austenitic carbon content in steel based on X-ray diffraction according to claim 1, characterized in that, The lattice constants are calculated using the Scherrer equation: Where λ is the wavelength of the Co target. The diffraction angle is the orientation angle of austenite. , , This refers to the crystal plane index.

4. The method for determining the austenitic carbon content in steel based on X-ray diffraction according to claim 1, characterized in that, Calculate the percentage of carbon in the austenite. : in, for The lattice constant of the phase, This indicates the percentage of carbon in austenite.

5. The method for determining the austenitic carbon content in steel based on X-ray diffraction according to claim 1, characterized in that, The diffraction experiment was conducted using an X-ray diffractometer with a Co target, and the tube voltage and tube current were adjusted to obtain the diffraction pattern.

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