Method for measuring diameter of spherical inclusions in steel sample
By performing a series of sectioning and image analysis on steel samples, the actual diameter of spherical inclusions is calculated, which solves the problem of inaccurate measurement in the existing technology and realizes a simple and efficient measurement method.
Patent Information
- Application Number
- CN202211360485.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-11-02
- Publication Date
- 2025-10-17
- Estimated Expiration
- 2042-11-02
AI Technical Summary
Existing technologies are unable to accurately measure the actual diameter of spherical inclusions in steel samples, resulting in inaccurate measurement results.
By serially slicing the polished surface of the steel sample, a series of thin-section images of the spherical inclusions are obtained, and the semicircular thin sections with the longest chord are screened out. The actual diameter of the spherical inclusion is calculated using the measured values of the straight segments and line segments.
It provides a simple and efficient method to accurately measure the actual diameter of spherical inclusions. The results are reliable and can be operated without special sample preparation and training.
Smart Images
Figure CN115684235B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of metallurgy, in particular to a method for measuring the diameter of spherical inclusions in a steel sample. BACKGROUND
[0002] In a steel sample, the existence of spherical inclusions has a great influence on the performance of steel. At present, the level of spherical inclusions is mainly evaluated by metallographic method, and the diameter is an important indicator for evaluating the level of spherical inclusions.
[0003] In the prior art, the method for measuring the diameter of spherical inclusions in a steel sample is to prepare the test surface of the sample by a standard metallographic sample preparation method to obtain a surface polishing state, and then observe the morphology of the inclusions by an optical microscope or a scanning electron microscope and test the diameter thereof. The diameter tested by this method is the diameter of the cross section of the sphere corresponding to the spherical inclusions rather than the actual diameter of the sphere. Different degrees of grinding and polishing during sample preparation will result in a large difference in the cross-sectional diameter of the same sphere, and the result is unreliable.
[0004] Therefore, it is necessary to design a method for accurately obtaining the actual diameter of spherical inclusions in a steel sample.
[0005] CONTENT
[0006] Therefore, the technical problem to be solved by the present application is to overcome the defect that the prior art cannot accurately measure the diameter of spherical inclusions in a steel sample, and to provide a method for accurately measuring the diameter of spherical inclusions in a steel sample.
[0007] To solve the above technical problems, the technical scheme of the present application is as follows:
[0008] A method for measuring the diameter of spherical inclusions in a steel sample, comprising:
[0009] S1, polishing the measured surface of the steel sample so that the measured surface of the steel sample is a polished surface;
[0010] S2, selecting a spherical inclusion in the polished surface of the steel sample, slicing the spherical inclusion in a direction perpendicular to the polished surface to obtain images of a series of thin sections of the spherical inclusion perpendicular to the polished surface;
[0011] S3, selecting a thin section of a semicircle with the longest chord from the images of the series of thin sections of the spherical inclusion;
[0012] S4, drawing any two straight line segments D1 and D2 parallel to the chord and not coinciding on the thin section of the semicircle with the longest chord, the two ends of the straight line segments D1 and D2 respectively terminate at the edge of the circular arc, and the line segment connecting the center point of the straight line segment D1 and the center point of the straight line segment D2 is Δd, and the values of D1, D2 and Δd are measured.
[0013] S5, the measured D1 and D2 and the value of Δd are substituted into the formula, and the diameter of the spherical inclusion is calculated.
[0014] Further, before the step of S1, the following steps are further included:
[0015] The steel sample sheet is cut into a sheet-shaped rectangular steel sample sheet by wire cutting;
[0016] The six surfaces of the steel sample sheet are polished until the surface of the steel sample sheet is free of cutting marks;
[0017] The polished steel sample sheet is ultrasonically cleaned to obtain the steel sample in step S1.
[0018] Further, in the step of S1, the measured surface of the steel sample is a side surface with the largest surface area of the steel sample.
[0019] Further, in the step of S2, the steel sample is loaded into the dual-beam scanning electron microscope, and the largest diameter spherical inclusion observed in the polished surface of the steel sample is selected as the selected spherical inclusion.
[0020] Further, before the step of serially slicing the spherical inclusion in the direction perpendicular to the polished surface, a carbon layer with a predetermined thickness is sprayed on the surface of the spherical inclusion, and the length and width of the carbon layer cover the spherical inclusion.
[0021] Further, in the step of S2, when the spherical inclusion is serially sliced in the direction perpendicular to the polished surface, the thickness of each slice is the same.
[0022] Further, in the step of S2, a camera is used to obtain an image of the series of slices of the spherical inclusion in the direction perpendicular to the polished surface.
[0023] Further, in the step of S5, the diameter of the spherical inclusion
[0024]
[0025] The technical scheme of the present application has the following advantages:
[0026] 1.The method for measuring the diameter of spherical inclusions in a steel sample provided by the application, a series of sections of the spherical inclusions on the polished surface of the steel sample are made along the direction perpendicular to the polished surface, and the images of the series of sections of the spherical inclusions are obtained, one section of the longest chord semicircle is selected from the images of the series of sections of the spherical inclusions as the section for actual diameter calculation, two straight line segments D1 and D2 parallel to the chord and not coinciding with each other are drawn on the section of the longest chord semicircle, and the line segment Δd between the center point of the straight line segment D1 and the center point of the straight line segment D2, the actual diameter of the spherical inclusion can be calculated through the measured values of D1, D2 and Δd, the measuring method is simple and efficient, the result is accurate, there is no special requirement for sample preparation, and there is no special requirement for the tester, simple training can calculate, and the deficiency that the actual diameter of the spherical inclusion cannot be accurately obtained at present is made up. BRIEF DESCRIPTION OF DRAWINGS
[0027] In order to more clearly illustrate the technical solutions in the specific embodiments of the application or the prior art, the drawings needed to be used in the description of the specific embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.
[0028] Figure 1 The schematic diagram for calculating the actual diameter of the spherical inclusion in the embodiments of the application;
[0029] Figure 2 The schematic diagram of the series of sections in the embodiments of the application;
[0030] Figure 3 The section image of the longest chord semicircle in the embodiments of the application. DETAILED DESCRIPTION
[0031] The technical solutions of the application will be described clearly and completely in combination with the drawings. Obviously, the described embodiments are some of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.
[0032] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0033] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.
[0034] like Figure 1 A method for measuring the diameter of spherical inclusions in a steel sample as shown in FIG. 3 includes the following steps:
[0035] Step S1: polishing the tested surface of the steel sample so that the tested surface of the steel sample is a polished surface.
[0036] Specifically, a steel sample is prepared using a conventional metallographic sample preparation method. The steel sample is rectangular, and the surface to be tested is generally the side of the steel sample with the largest surface area. The conventional metallographic sample preparation method includes the following steps: first, using wire cutting to cut a rectangular sheet of steel sample from the steel workpiece to be tested; then, grinding and polishing the six sides of the steel sample sheet until no cutting marks remain on the surface of the steel sample sheet; and finally, ultrasonically cleaning the ground and polished steel sample sheet to obtain the steel sample in step S1.
[0037] Step S2: selecting a spherical inclusion on the polished surface of the steel sample, performing a series of slices on the spherical inclusion in a direction perpendicular to the polished surface, and obtaining images of a series of thin slices of the spherical inclusion in the direction perpendicular to the polished surface.
[0038] Specifically, a steel sample is placed in a dual-beam scanning electron microscope, and the spherical inclusion with the largest diameter observed on the polished surface of the steel sample is selected as the spherical inclusion. In practice, there may be one or more spherical inclusions observed on the polished surface of the steel sample, and the sizes of these spherical inclusions may vary. Selecting the spherical inclusion with the largest diameter allows for a more accurate assessment of the spherical inclusion grade.
[0039] Before the step of serially slicing the spherical inclusions in the direction perpendicular to the sectioned surface, the surface of the spherical inclusions can be sprayed with a carbon layer of a predetermined thickness, and the length and width of the carbon layer cover the spherical inclusions; for example, a carbon layer of 0.5 μm in thickness. The carbon layer can reduce the reflection of the polished surface of the steel sample, and form a clear light-dark boundary with the part without the carbon layer, thereby facilitating the observation of the circular arc profile of the spherical inclusions.
[0040] Specifically, when the spherical inclusions are serially sliced, the thickness of each slice is the same; after slicing, the images of the serial slices of the spherical inclusions are obtained by using a camera.
[0041] Step S3, one slice of the semicircle with the longest chord is selected from the images of the serial slices of the spherical inclusions.
[0042] Step S4, two straight line segments D1 and D2 parallel to the chord and not coinciding with each other are drawn on the image of the slice of the semicircle with the longest chord, and the two ends of the straight line segments D1 and D2 terminate at the edges of the circular arc, and the line segment connecting the center point of the straight line segment D1 and the center point of the straight line segment D2 is Δd, and the values of D1, D2 and Δd are measured.
[0043] Step S5, the values of D1, D2 and Δd measured are substituted into the formula to calculate the diameter of the spherical inclusion.
[0044] It can be known from the right triangle formula that:
[0045] Formula (1)
[0046] Formula (2)
[0047] Formula (1)-(2), formula (3) can be calculated
[0048] The result of formula (3) is substituted into formula (1) to calculate R:
[0049]
[0050] The actual diameter of the sphere is:
[0051] (4)
[0052] The values of D1, D2 and Δd measured are substituted into formula (4) to obtain the actual diameter D of the sphere.
[0053] The method for measuring the diameter of spherical inclusions in the steel sample comprises the following steps: slicing the spherical inclusions on the polished surface of the steel sample in the direction perpendicular to the polished surface, and obtaining images of the series of thin sections of the spherical inclusions; selecting a thin section with the longest chord semicircle as the thin section for actual diameter calculation from the images of the series of thin sections; drawing two straight line segments D1 and D2 on the image of the thin section with the longest chord semicircle, the two straight line segments being parallel to the chord and not coinciding with each other; drawing a line segment Δd between the center point of the straight line segment D1 and the center point of the straight line segment D2; and calculating the actual diameter of the spherical inclusions by the measured values of D1, D2 and Δd. The method is simple and efficient, the result is accurate, no special requirements are needed for sample preparation and testers, and the method can be calculated after simple training, thereby making up for the deficiency that the actual diameter of the spherical inclusions cannot be accurately obtained at present.
[0054] The ship plate steel weld zone sample is selected as the embodiment object, and the invention content is further described.
[0055] 1. The sample is cut into a 10mm*20mm*2mm (length* width*thickness) thin section by wire cutting, and the six surfaces of the sample are polished by 800 mesh sandpaper until there is no wire cutting mark, and then the sample is cleaned by ultrasonic cleaning in alcohol;
[0056] 2. The sample is hot-embedded, and then the sample is prepared into a polished surface according to the conventional metallographic method, and a small square piece is taken out;
[0057] 3. The sample is loaded into a double-beam scanning electron microscope, the spherical inclusion with the largest diameter in the measured surface is found, a 0.5μm thick carbon layer is sprayed on the surface of the spherical inclusion, and the length and width of the carbon layer are based on covering the spherical inclusion;
[0058] 4. The single thickness is set, the spherical inclusion is sliced, and a photo is taken;
[0059] 5. The photo with the longest chord is found in the series of sliced photos of the spherical inclusion, as shown in FIG. 5, two straight line segments D1 and D2 are drawn on the photo, the two straight line segments being not coinciding and parallel to the chord, and a line segment Δd between the center point of the straight line segment D1 and the center point of the straight line segment D2 is drawn, D1=9.912μm, D2=7.392μm, and Δd=1.092μm are measured; Figure 3 6. The formula is brought in, and the actual diameter of the spherical inclusion is calculated as 13.315μm (rounded).
[0060]
[0061] Obviously, the above embodiments are merely example for clearly illustrating but not limitation to the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments are not required to be enumerated and it is impossible to enumerate all the embodiments. The changes or variations derived from the above are still within the protection scope of the present application.
Claims
1. A method for measuring the diameter of spherical inclusions in steel samples, characterized in that: include: S1. Polishing the tested surface of the steel sample so that the tested surface of the steel sample is a polished surface; S2. selecting a spherical inclusion on the polished surface of the steel sample, performing a series of thin-section slices on the spherical inclusion in a direction perpendicular to the polished surface, and obtaining images of a series of thin sections of the spherical inclusion in the direction perpendicular to the polished surface; S3, selecting a thin slice with the longest semicircle chord from the images of a series of thin slices of spherical inclusions; S4. Draw two arbitrary straight line segments D1 and D2 on a thin sheet of the semicircle with the longest chord, parallel to the chord and not overlapping. End the ends of straight line segments D1 and D2 at the edges of the arc. Measure the line segment Δd connecting the center point of straight line segment D1 and the center point of straight line segment D2. S5. Substitute the measured values of D1, D2 and Δd into the formula to calculate the diameter of the spherical inclusion; the diameter of the spherical inclusion is:
2. The method for measuring the diameter of spherical inclusions in steel samples according to claim 1, characterized in that: Before step S1, the method further includes the following steps: Use wire cutting to cut the steel workpiece to be tested into sheet-shaped rectangular steel sample slices; The six sides of the steel sample slice are ground and polished until there are no cutting marks on the surface of the steel sample slice; The steel sample slice after grinding and polishing is ultrasonically cleaned to obtain the steel sample in step S1.
3. The method for measuring the diameter of spherical inclusions in steel samples according to claim 1, characterized in that: In step S1, the measured surface of the steel sample is the side surface of the steel sample with the largest surface area.
4. The method for measuring the diameter of spherical inclusions in steel samples according to claim 1, characterized in that: In step S2, the steel sample is placed in a dual-beam scanning electron microscope, and the spherical inclusion with the largest diameter observed on the polished surface of the steel sample is selected as the spherical inclusion.
5. The method for measuring the diameter of spherical inclusions in steel samples according to claim 4, characterized in that: In step S2, before the step of performing a series of slices on the spherical inclusions along a direction perpendicular to the polishing surface, a carbon layer of a predetermined thickness is sprayed on the surface of the spherical inclusions, and the length and width of the carbon layer cover the spherical inclusions.
6. The method for measuring the diameter of spherical inclusions in steel samples according to claim 1, characterized in that: In the step S2, when the spherical inclusion is sliced in series along a direction perpendicular to the polishing surface, the thickness of each slice is the same.
7. The method for measuring the diameter of spherical inclusions in steel samples according to claim 1, characterized in that: In step S2, a camera is used to obtain a series of thin-section images of the spherical inclusions perpendicular to the polishing surface.