阅读说明：本技术 一种热轧盘条表面氧化铁皮结构快速分析方法 (Method for rapidly analyzing oxide scale structure on surface of hot-rolled wire rod ) 是由 罗新中 肖命冬 曾赞喜 林晏民 李富强 朱祥睿 章玉成 麻国晓 张兆洋 董凤奎 于 2019-07-25 设计创作，主要内容包括：本发明涉及一种热轧盘条表面氧化铁皮结构快速分析方法,其工艺步骤是：首先进行试样的制备,切割出待测热轧盘条横截面试样,采用保边型热镶嵌料对试样进行镶嵌,对试样进行磨平与抛光,制备出所需试样；再将制备好的截面试样用导电胶带固定在扫描电镜的样品台上,获得清晰的不同层次氧化铁皮形貌像；采用能谱对不同层次氧化铁皮进行微区成分分析；再采用扫描电镜测量尺对氧化铁皮厚度进行测量,在能谱分析位置分别测量各个层次氧化铁皮厚度以及氧化铁皮总厚度；最后得出热轧盘条表面氧化铁皮厚度、组分的具体信息。解决了易破碎、导电性能差的氧化铁皮样品的制备困难及氧化铁皮组分定量表征检测复杂、效率低的问题,克服了常规金相显微镜检测无法精确定量表征氧化铁皮微观结构的问题。(The invention relates to a method for quickly analyzing a scale structure on the surface of a hot-rolled wire rod, which comprises the following process steps: firstly, preparing a sample, cutting out a hot-rolled wire rod cross section sample to be detected, inlaying the sample by adopting an edge-protecting type hot inlaying material, and grinding and polishing the sample to prepare the required sample; fixing the prepared cross-section sample on a sample table of a scanning electron microscope by using a conductive adhesive tape to obtain clear appearance images of the iron scales at different levels; analyzing micro-area components of the iron scales at different levels by adopting an energy spectrum; measuring the thickness of the iron scale by adopting a scanning electron microscope measuring scale, and respectively measuring the thickness of each layer of the iron scale and the total thickness of the iron scale at the energy spectrum analysis position; and finally obtaining the specific information of the thickness and the components of the iron scale on the surface of the hot-rolled wire rod. The method solves the problems of difficult preparation of an iron scale sample which is easy to crush and poor in conductivity, complex quantitative characterization and detection of iron scale components and low efficiency, and solves the problem that the microstructure of the iron scale cannot be accurately and quantitatively characterized in the conventional metallographic microscope detection.)

1. A method for rapidly analyzing the scale structure on the surface of a hot-rolled wire rod is characterized by comprising the following process steps:

s1: preparing a sample, namely cutting out a sample of the cross section of the hot-rolled wire rod to be detected by using a precision cutting machine, inlaying the sample by using an edge-protecting type hot inlaying material, and grinding and polishing the sample by using a grinding and polishing machine to prepare the required sample;

s2, observing the appearance of the scanning electron microscope, fixing the prepared cross-section sample on a sample table of the scanning electron microscope by using a conductive adhesive tape, vacuumizing, adding filament current, centering and resolving the astigmatism, keeping the working distance of 8 ~ 10mm, and adjusting the brightness and the contrast so as to obtain clear appearance images of the iron scales in different layers;

s3: performing energy spectrum component analysis, namely performing micro-area component analysis on the iron scales at different layers by adopting an energy spectrum, turning on an X-ray energy spectrometer, and entering an energy spectrum analysis program after the current emitted by the filament is stable; selecting complete, representative or marked iron scale positions for analysis, and respectively carrying out micro-area component analysis on each layer of the iron scale, wherein three points are respectively taken at positions close to the middle of each layer of the iron scale for micro-area component analysis in consideration of the energy spectrum working principle and the guarantee of the representativeness of the detection result;

s4: measuring the thickness of the iron scale, namely measuring the thickness of the iron scale by adopting a scanning electron microscope measuring scale, and respectively measuring the thickness of the iron scale at each layer and the total thickness of the iron scale at an energy spectrum analysis position;

s5: and (3) carrying out data processing according to the energy spectrum analysis result, and according to the general principle of hot-rolled wire rod iron scale structure distribution: outermost layer of Fe₂O₃Second outer layer Fe₃O₄The innermost FeO and the atomic ratio of Fe and O elements are analyzed by combining an energy spectrum to determine the specific components of each layer of the iron scale; and finally, integrating the measurement results of the thickness of each layer and the total thickness of the scale to obtain the specific information of the thickness and the components of the scale on the surface of the hot-rolled wire rod.

2. The method for rapidly analyzing the scale structure on the surface of the hot-rolled wire rod as claimed in claim 1, wherein the method comprises the following steps: the purpose of using the edge-protected thermal insert in step S1 is to prevent the scale from peeling off and separating from the substrate during the inlaying and subsequent polishing processes, which affects the subsequent analysis.

3. The method for rapidly analyzing the scale structure on the surface of the hot-rolled wire rod as claimed in claim 1, wherein the method comprises the following steps: the working process of the grinding and polishing machine comprises coarse grinding, fine grinding, polishing and cleaning.

4. The method for rapidly analyzing the scale structure on the surface of the hot-rolled wire rod as claimed in claim 1, wherein the method comprises the following steps: the required sample in said step S1 is required to have a high surface finish and a complete sample edge.

5. The method for rapidly analyzing the scale structure on the surface of the rolled wire rod as claimed in claim 1, wherein the method comprises the following steps: in the step S2, the image may be enlarged to fill the whole field of view with the scale to obtain an ideal observation field of view, and the contrast difference between the secondary electron image or the backscattered electron image is adjusted to facilitate the capture of the electronic image by the spectrometer.

6. The method for rapidly analyzing the scale structure on the surface of the hot-rolled wire rod as claimed in claim 1, wherein the method comprises the following steps: in step S3, considering that the energy spectrum is semi-quantitative analysis and uncertainty of light element analysis, C and previous elements are removed from the energy spectrum result, only elements after C are retained, and the result of atomic percent of elements in energy spectrum analysis is output.

Technical Field

The invention relates to the technical field of structure analysis methods, in particular to a method for quickly analyzing a scale structure on the surface of a hot-rolled wire rod.

Background

The hot-rolled wire rod is mostly subjected to deep processing such as drawing, cold heading and the like, and the pretreatment procedure of the deep processing is to remove the surface iron oxide scale. When the scale is not completely removed, a large amount of scale remains on the surface of the wire rod, and scratches the surface of the die and the steel wire during drawing, so that the service life of the wire-drawing die is shortened, and the surface of the steel wire has defects of scars and the like, and wire breakage is caused in severe cases. The current common method for removing the iron scale comprises acid washing and mechanical shelling, wherein the acid washing adopts chemical reaction between acid and the iron scale to dissolve the surface iron scale, so that the thinner the iron scale is, the better the iron scale is required to be removed by acid washing. Mechanical peeling is realized by means of external forces such as vibration, shot blasting, deformation and the like, so that the iron scale peels off the matrix, and relatively speaking, the thicker the iron scale is, the easier the matrix is to be peeled off integrally, and the better the peeling effect is.

In addition, the iron scale of the hot-rolled wire rod generally has three structural compositions, namely the outermost layer Fe₂O₃Second outer layer of Fe₃O₄The phase composition of FeO and iron scale in the inner layer is generally composed of 2 ~ 3 oxides with different compositions theoretically, the oxygen content of each phase is not constant and exists in a certain range as can be seen from a ferrite phase diagram₃O₄Is a black crystal with magnetism, Fe₂O₃The crystal structure is corundum type (hexagonal close packed). The three-layer iron scale structure has different sensitivities to acid washing and shelling, for example, the low-price iron scale (FeO) is easier to mechanically shell, and the high-price iron scale (Fe)₂O₃) It is easier to pickle.

Therefore, the structure of the iron scale is analyzed in detail, and the thickness and the structural components of the iron scale can be controlled by adjusting the rolling and cooling processes in the production process. The iron oxide structure is analyzed before acid washing or shelling, a proper acid washing process or shelling process can be formulated through the thickness of the iron scale and components of each layer, and processing cost is effectively reduced on the premise of ensuring the removal quality of the iron scale.

At present, the surface scale of a hot-rolled wire rod is measured, and a wire rod sample is generally processed, inlaid and ground, and observed by an optical microscope in a polished state. And selecting an area with uniform thickness of the iron scale, and measuring the thickness of the iron scale at least five points by using image analysis software, wherein the average of the five values is the average thickness value of the iron scale. The method is simple to operate, but cannot characterize the structure of the iron scale and the thickness of the iron scale with different components.

The patent with the publication number of CN101879530A discloses a soft measurement method for the thickness of iron scale on the surface of hot continuous rolling strip steel, which belongs to the technical field of steel rolling and mainly relates to the prediction of the thickness of the iron scale in the hot continuous rolling process in real time. However, the measuring method establishes a soft thickness measuring model, and predicts the thickness of the scale in the hot continuous rolling process by establishing real-time communication with the hot continuous rolling process machine. Is not suitable for the actual measurement of the iron scale on the surface of the wire rod.

Chinese patent with publication number CN103837557A, entitled "method for characterizing microstructure of cross-sectional scale of hot-rolled steel plate by EBSD", belongs to the technical field of physical property inspection of metal materials. And analyzing the crystalline material by using data such as phase, orientation, stress state and the like of the sample obtained by back scattering diffraction information formed after the electron beam irradiates the surface of the sample. The EBSD represents the iron scale structure and can obtain detailed component information, but the EBSD is not popularized in laboratories at present, most laboratories have no detection capability, EBSD samples have high requirements on surface residual stress, sample preparation difficulty is high, subsequent analysis process is complex, detection efficiency is low, and the EBSD is not suitable for batch detection.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for quickly analyzing the surface scale structure of a hot-rolled wire rod, which solves the problems of difficult preparation of a scale sample which is easy to crush and poor in conductivity, complex quantitative characterization and detection of scale components and low efficiency, and solves the problem that the microstructure of the scale cannot be accurately and quantitatively characterized by conventional metallographic microscope detection.

The technical purpose of the invention is realized by the following technical scheme: a method for rapidly analyzing the scale structure on the surface of a hot-rolled wire rod comprises the following process steps:

s1: preparing a sample, namely cutting out a sample of the cross section of the hot-rolled wire rod to be detected by using a precision cutting machine, inlaying the sample by using an edge-protecting type hot inlaying material, and grinding and polishing the sample by using a grinding and polishing machine to prepare the required sample;

s2, observing the appearance of the scanning electron microscope, fixing the prepared cross-section sample on a sample table of the scanning electron microscope by using a conductive adhesive tape, vacuumizing, adding filament current, centering and resolving the astigmatism, keeping the working distance of 8 ~ 10mm, and adjusting the brightness and the contrast so as to obtain clear appearance images of the iron scales in different layers;

s3: performing energy spectrum component analysis, namely performing micro-area component analysis on the iron scales at different layers by adopting an energy spectrum, turning on an X-ray energy spectrometer, and entering an energy spectrum analysis program after the current emitted by the filament is stable; selecting complete, representative or marked iron scale positions for analysis, and respectively carrying out micro-area component analysis on each layer of the iron scale, wherein three points are respectively taken at positions close to the middle of each layer of the iron scale for micro-area component analysis in consideration of the energy spectrum working principle and the guarantee of the representativeness of the detection result;

s4: measuring the thickness of the iron scale, namely measuring the thickness of the iron scale by adopting a scanning electron microscope measuring scale, and respectively measuring the thickness of the iron scale at each layer and the total thickness of the iron scale at an energy spectrum analysis position;

s5: and (3) carrying out data processing according to the energy spectrum analysis result, and according to the general principle of hot-rolled wire rod iron scale structure distribution: outermost layer of Fe₂O₃Second outer layer Fe₃O₄The innermost FeO and the atomic ratio of Fe and O elements are analyzed by combining an energy spectrum to determine the specific components of each layer of the iron scale; and finally, integrating the measurement results of the thickness of each layer and the total thickness of the scale to obtain the specific information of the thickness and the components of the scale on the surface of the hot-rolled wire rod.

Furthermore, the edge-protected thermal insert material is used in step S1 to prevent the scale from peeling off and separating from the substrate during the embedding and subsequent polishing process, which affects the subsequent analysis.

Further, the working process of the grinding and polishing machine comprises coarse grinding, fine grinding, polishing and cleaning.

Further, the required sample in said step S1 is required to have a high surface finish and a complete sample edge.

Furthermore, in the step S2, the image may be enlarged to make the iron scale fill the whole field of view to obtain an ideal observation field of view, and the contrast difference between the secondary electron image and the backscattered electron image is adjusted to facilitate the spectrometer to capture the electronic image.

Further, in the step S3, considering that the energy spectrum is a semi-quantitative analysis and uncertainty of the light element analysis, C and the previous elements are removed from the energy spectrum result, only the elements after C are retained, and the result of atomic percent of the elements of the energy spectrum analysis is output.

In conclusion, the invention has the following beneficial effects:

(1) the microscopic morphology of the iron scale can be clearly and visually displayed, and the microstructure characteristics of the iron scale, such as the microscopic morphology, the thickness, the components and the like, can be rapidly and quantitatively analyzed;

(2) compared with EBSD or XRD quantitative analysis of the iron scale, the method has the advantages of low sample preparation requirement, simple analysis process, low equipment requirement and easy realization;

(3) the method is simple and easy to implement, and can be applied to batch product research and development and analysis tests to realize accurate control on generation, removal and the like of the iron scale.

Drawings

FIG. 1 is a diagram of measuring the appearance and thickness of an embodiment of the invention by using a ferric oxide sheet scanning electron microscope;

FIG. 2 is a scanning electron microscope image of the appearance and thickness of the iron dioxide coating according to the embodiment of the present invention.

Detailed Description

The invention is described in detail below with reference to the figures and examples.