Method for measuring thickness of iron oxide scale of wire rod

Abstract

The invention provides a method for measuring the thickness of a steel wire rod oxide scale, and belongs to the technical field of material analysis and testing. The method comprises the following steps: cutting a to-be-detected wire rod with a preset length to prepare a sample; grinding and polishing the detection surface of the sample to obtain a smooth detection surface; collecting an electronic image of the detection surface through a scanning electron microscope; and determining the thickness of the steel wire rod oxide scale based on the electronic image. The method comprises the following steps: cutting a to-be-detected wire rod to prepare a sample, grinding and polishing the sample, obtaining an electronic image through a scanning electron microscope, and measuring a plurality of oxide scale thicknesses; according to the method, the maximum value, the minimum value and the average value are determined based on the thicknesses of the multiple oxide scales, comprehensive and accurate characterization of the thicknesses of the oxide scales of the wire rods is achieved, the problem that the microstructure of the oxide scales cannot be accurately and quantitatively characterized through conventional metallographic microscope detection is solved, and an accurate basis is provided for subsequent oxide scale removal; and the oxide scale removal efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of materials analysis and testing technology, and in particular to a method for determining the thickness of iron oxide scale on wire rods. Background Technology

[0002] In the wire drawing process of industrial wire rods, residual iron oxide scale on the surface of the wire rod can significantly affect subsequent processing. The presence of iron oxide scale not only damages the drawing dies and the surface of the wire, shortening the die's lifespan, but can also lead to production problems such as wire breakage. Currently, the main methods for removing iron oxide scale include pickling and mechanical descaling. Pickling requires a thinner layer of iron oxide scale on the wire rod to shorten pickling time and improve acid utilization; while mechanical descaling requires a thicker layer of iron oxide scale, causing the scale to flake off in chunks during repeated bending, thereby improving descaling efficiency and reducing surface residue. Therefore, accurately measuring the thickness and layering structure of the iron oxide scale is crucial for the selection and optimization of the production process.

[0003] In existing technologies, the nitric acid-alcohol etching method cannot effectively distinguish the structure of different layers of iron oxide scale, making it difficult to quantitatively and qualitatively measure the thickness and proportion of each layer. While the currently used X-ray diffraction method can achieve the detection purpose, it suffers from high testing costs and sample preparation difficulties, hindering efficient and low-cost microstructural inspection of iron oxide scale. Furthermore, this method is time-consuming and inefficient, making it difficult to provide timely and effective guidance for production. These technical shortcomings severely restrict the accuracy and timeliness of iron oxide scale detection.

[0004] Therefore, there is an urgent need for a method to determine the thickness of iron oxide scale on wire rods. Summary of the Invention

[0005] In view of this, the present invention provides a method for measuring the thickness of iron oxide scale on wire rod, which uses scanning electron microscopy to measure the thickness of iron oxide scale on the surface of wire rod, taking into account both the accuracy and timeliness of iron oxide scale detection.

[0006] Therefore, the present invention provides the following technical solution:

[0007] A method for determining the thickness of iron oxide scale on wire rod, comprising: Samples are prepared by cutting the wire rod to be tested to a predetermined length; The test surface of the sample is ground and polished to obtain a smooth test surface; Electronic images of the detection surface are acquired using a scanning electron microscope; The thickness of the iron oxide scale on the wire rod is determined based on the electronic image.

[0008] Further, the preparation of the sample by cutting a wire rod of a predetermined length for testing includes: A 1-2 cm section of the wire rod to be tested was cut radially using wire cutting technology as a sample.

[0009] Further, the test surface of the sample is ground and polished to obtain a smooth test surface, including: The radial cross-section of the wire rod is used as the inspection surface; Use sandpaper to grind the test surface of the sample; After grinding, the test surface is finely polished with a polishing agent until it is smooth and free of scratches.

[0010] Furthermore, the acquisition of electronic images of the detection surface using a scanning electron microscope includes: Images of the detection surface are acquired based on preset operating parameters; the preset operating parameters include: The accelerating voltage is 15kV-25kV, the working distance is 9mm-10mm, the magnification is 500x-5000x, and the scanning speed is 10-30 seconds / frame.

[0011] Furthermore, the preset operating parameters also include: brightness set to 60%-80% of full scale value, and contrast set to 40%-60% of full scale value.

[0012] Further, determining the thickness of the iron oxide scale on the wire rod based on the electronic image includes: A grayscale thresholding algorithm was used to identify the interface boundary between the iron oxide scale and the substrate, and the interface of the iron oxide scale layer was located based on the grayscale abrupt change features of the image. The measurement line segment is drawn along the interface normal using an image analysis tool, and the pixel distance between the two boundary coordinates is obtained as the thickness of the iron oxide scale.

[0013] Advantages and positive effects of the present invention: This method involves preparing a sample from the wire rod to be tested, and after polishing the sample, obtaining an electron image using a scanning electron microscope to measure the thickness of multiple iron oxide scales. Based on these multiple iron oxide scale thicknesses, the maximum, minimum, and average values ​​are determined to achieve a comprehensive and accurate characterization of the iron oxide scale thickness of the wire rod. This overcomes the problem that conventional metallographic microscopy cannot accurately and quantitatively characterize the microstructure of iron oxide scale, providing an accurate basis for subsequent iron oxide scale removal and improving the efficiency of iron oxide scale removal. Attached Figure Description

[0014] 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.

[0015] Figure 1 This is a flowchart illustrating the method for determining the thickness of iron oxide scale on wire rod in the embodiments; Figure 2 The image is a scanning electron microscope image acquired in the example. Detailed Implementation

[0016] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0017] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0018] This invention provides a method for determining the thickness of iron oxide scale on wire rod, which solves the problem of difficulty in preparing easily broken iron oxide scale samples with poor electrical conductivity, and lays the foundation for accurate control of the properties of iron oxide scale on wire rod in on-site production.

[0019] A method for determining the thickness of iron oxide scale on wire rod, comprising: Samples are prepared by cutting the wire rod to be tested to a predetermined length; The test surface of the sample is ground and polished to obtain a smooth test surface; Electronic images of the detection surface are acquired using a scanning electron microscope; The thickness of the iron oxide scale on the wire rod was determined based on electronic images.

[0020] 1. Prepare a sample by cutting a wire rod of a predetermined length to be tested.

[0021] A 1-2 cm section of the wire rod to be tested was cut radially using wire cutting technology as a sample.

[0022] 2. Grind and polish the test surface of the sample to obtain a smooth test surface; Using the transverse side of the wire rod as the testing surface, the testing surface is ground and polished to obtain the sample: The test surface of the sample was polished sequentially using sandpaper ranging from 120 grit to 1200 grit. After grinding, the test surface of the sample is finely polished with a polishing agent until the test surface is smooth and free of scratches; The sample was then cleaned and dried, and used as a test sample.

[0023] 3. Electronic images of the detection surface are acquired using a scanning electron microscope.

[0024] 1) Fix the sample on the sample stage of the scanning electron microscope with conductive tape, and then perform vacuuming, filament current application, and centering to eliminate astigmatism in sequence. 2) Acquire images of the detection surface based on preset working parameters.

[0025] Operating parameters include: accelerating voltage, working distance, magnification, and scanning speed.

[0026] 3) Obtain high-definition electronic images at preset magnification and scanning speed.

[0027] Scanning electron microscopes (SEMs) are widely used in materials science, biology, physics and many other fields. They form images by scanning the surface of a sample with a focused electron beam and detecting reflected or emitted secondary electrons and backscattered electrons.

[0028] 4. Determining the thickness of iron oxide scale on wire rod based on electronic images: 1) Use scanning electron microscopy to obtain the continuous iron oxide scale on the test surface and measure the thickness of the iron oxide scale.

[0029] 2) Measure the thickness at the thickest and thinnest points separately. Determine the values ​​at 5 points during each measurement.

[0030] 3) Data analysis: The average of the 5 measured values ​​is used to obtain the thickest iron oxide scale, the average thickness, and the average thickness of the thinnest iron oxide scale, which are used to characterize the iron oxide scale thickness of the wire rod.

[0031] Example Combination Figure 1 As shown, the method for determining the thickness of iron oxide scale on 70# wire rod includes: 1. Prepare a sample by cutting a wire rod of a predetermined length to be tested.

[0032] A 1.5cm section of the wire rod to be tested was cut radially using wire cutting technology, ensuring that the iron oxide scale layer on the sample surface remained intact.

[0033] 2. Grind and polish the test surface of the sample to obtain a smooth test surface.

[0034] Using the transverse side of the wire rod as the testing surface, the testing surface is ground and polished to obtain the sample: The sample is inlaid with a hot-mounting material, then placed in a grinding disc, and the test surface is polished with sandpaper at 120 grit, 500 grit, 800 grit, and 1200 grit respectively, so that the test surface of the sample is bright and smooth.

[0035] Using 2.5 The diamond polishing compound is used to finely polish the test surface of the sample for 0 to 5 minutes until the surface is smooth and free of scratches. Finally, the sample is cleaned and dried.

[0036] 3. Scanning electron microscope (SEM) image acquisition of sample detection surface images.

[0037] 1) Fix the sample on the sample stage of the scanning electron microscope with conductive tape, and then perform vacuuming, filament current application, and centering to eliminate astigmatism in sequence. 2) Acquire images of the detection surface based on preset working parameters.

[0038] Operating parameters include: acceleration voltage, brightness, contrast, and working distance.

[0039] The accelerating voltage is 15kV-25kV, the working distance is 9mm-10mm, the magnification is 500x-5000x, and the scanning speed is 10-30 seconds / frame.

[0040] Preferably, in this embodiment, the operating parameters are: accelerating voltage 20kV, working distance approximately 9.5mm, aperture 30 micrometers; adjust image contrast and brightness until there is a significant difference between the iron oxide layer and the substrate.

[0041] 3) Preset magnification to obtain high-definition electronic images when the scanning speed is less than 15 seconds / frame.

[0042] In this embodiment, the magnification is 3000 times, and a high-definition electronic image is obtained at a scanning speed of 25 seconds / frame.

[0043] Set the brightness to 60%-80% of full scale and the contrast to 40%-60% of full scale.

[0044] 4. Determine the thickness of iron oxide scale on wire rods based on electronic images.

[0045] 1) Use scanning electron microscopy to obtain the continuous iron oxide scale on the test surface and measure the thickness of the iron oxide scale.

[0046] A grayscale thresholding algorithm is used to identify the interface boundary between the iron oxide scale and the substrate, and the interface of the iron oxide scale layer is located based on the grayscale abrupt change features of the image. Measurement line segments are drawn along the interface normal using image analysis tools, and the pixel distance between the two boundary coordinates is obtained as the thickness of the iron oxide scale.

[0047] 2) Measure the thickness at the thickest and thinnest points separately. Determine the values ​​at 5 points during each measurement.

[0048] 3) Data analysis: The average of the 5 measured values ​​is used to obtain the thickest iron oxide scale, the average thickness, and the average thickness of the thinnest iron oxide scale, which are used to characterize the iron oxide scale thickness of the wire rod.

[0049] like Figure 2 As shown, in this embodiment, the thicknesses of the five points are 11.29µm, 13.15µm, 10.35µm, 11.21µm, and 11.05µm, respectively.

[0050] 3) Data analysis: Analysis of the 5 measured values ​​revealed that the thickest iron oxide scale was 13.15µm, the average thickness was 11.41µm, and the thinnest iron oxide scale was 10.35µm, which were used to characterize the thickness of the iron oxide scale on the wire rod.

[0051] 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 thickness of iron oxide scale on wire rod, characterized in that, include: Samples are prepared by cutting the wire rod to be tested to a predetermined length; The test surface of the sample is ground and polished to obtain a smooth test surface; Electronic images of the detection surface are acquired using a scanning electron microscope; The thickness of the iron oxide scale on the wire rod is determined based on the electronic image.

2. The method according to claim 1, characterized in that, The preparation of the sample by cutting the wire rod to be tested to a preset length includes: A 1-2 cm section of the wire rod to be tested was cut radially using wire cutting technology as a sample.

3. The method according to claim 1, characterized in that, Grinding and polishing the test surface of the sample to obtain a smooth test surface includes: The radial cross-section of the wire rod is used as the inspection surface; Use sandpaper to grind the test surface of the sample; After grinding, the test surface is finely polished with a polishing agent until it is smooth and free of scratches.

4. The method according to claim 1, characterized in that, The acquisition of electronic images of the detection surface using a scanning electron microscope includes: Images of the detection surface are acquired based on preset operating parameters; the preset operating parameters include: The accelerating voltage is 15kV-25kV, the working distance is 9mm-10mm, the magnification is 500x-5000x, and the scanning speed is 10-30 seconds / frame.

5. The method according to claim 4, characterized in that, The preset operating parameters also include: brightness set to 60%-80% of full scale value, and contrast set to 40%-60% of full scale value.

6. The method according to claim 1, characterized in that, Determining the thickness of the iron oxide scale on the wire rod based on the electronic image includes: A grayscale thresholding algorithm was used to identify the interface boundary between the iron oxide scale and the substrate, and the interface of the iron oxide scale layer was located based on the grayscale abrupt change features of the image. The measurement line segment is drawn along the interface normal using an image analysis tool, and the pixel distance between the two boundary coordinates is obtained as the thickness of the iron oxide scale.

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