CN115791793A - Quantitative analysis method for purity of heavy rail steel - Google Patents
Quantitative analysis method for purity of heavy rail steel Download PDFInfo
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- CN115791793A CN115791793A CN202211461192.7A CN202211461192A CN115791793A CN 115791793 A CN115791793 A CN 115791793A CN 202211461192 A CN202211461192 A CN 202211461192A CN 115791793 A CN115791793 A CN 115791793A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention discloses a quantitative analysis method for the purity of heavy rail steel, which is characterized in that a full-automatic microscope is used for quantitatively analyzing inclusions in a target area, evaluating the purity of the heavy rail steel and effectively monitoring the distribution of the inclusions and the condition of damaging the steel.
Description
Technical Field
The invention relates to a quantitative analysis method for the purity of heavy rail steel.
Background
The rail head nuclear damage refers to transverse fatigue cracks of the rail head, commonly known as rail head nuclear damage, and is called nuclear damage for short, and means that extremely complex stress distribution and stress states occur in the rail head under the action of train load, so that fine cracks transversely expand into the nuclear damage until the strength of steel around the nuclear damage is not enough to resist the stress under the action of wheel load, and the steel rail is suddenly brittle-broken. The rail head nuclear damage generally appears at 8-12mm from the tread and 5-10mm from the inner side, the direction of the rail head nuclear damage is close to vertical to the longitudinal section of the steel rail, and the rail head nuclear damage is the most dangerous steel rail damage which has the greatest threat to the travelling crane. The important reason for the formation of the nuclear damage is that the steel rail has internal defects such as inclusions, white spots, bubbles and the like caused by metallurgical defects in the manufacturing process, so that the evaluation of the types and the grades of the inclusions in the steel is very important for ensuring the quality of steel.
GB/T10561-2005 specifies a method for grading nonmetallic inclusions in steel, and a steel mill generally adopts the A method, namely the worst visual field method. The method only qualitatively evaluates the category and the grade of the non-metallic inclusions, has no relevant regulation on quantitative analysis, is very important for the quantitative analysis of the inclusions causing the nuclear damage of the steel rail, and the probability of the nuclear damage of the steel rail with the same grade of inclusions is not always the same, which is the target of researching the quantitative analysis of the inclusions. At present, no data report in this aspect is available.
Disclosure of Invention
The invention aims to provide a quantitative analysis method for the purity of heavy rail steel, which is used for quantitatively analyzing impurities in a nuclear injury area of a heavy rail, and is beneficial to controlling the purity of steel, improving the product quality and reducing accidents such as nuclear injury.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention relates to a quantitative analysis method for the purity of heavy rail steel, which mainly comprises the following steps:
1) Sampling
In order to research the level of inclusions in a rail region which is easy to generate nuclear damage, a sample is taken at the tread position of a rail head;
3) Metallographic sample preparation
The detection surface is the direction (longitudinal surface) of the steel rail parallel rolling, chamfering by a grinding machine, coarse grinding, fine grinding by abrasive paper, mechanical polishing, and finally the detection surface of the test sample is a mirror surface without water stains and stains;
3) Microscopic examination
Setting a zero point: the prepared metallographic specimen is inversely placed on an objective table of a metallographic microscope, the position is adjusted, a certain position under a sample tread is set as a zero point, a rectangular area is set, and a 100-time objective lens is used;
setting the value of n: selecting n points at intervals in a set rectangular area, sequentially focusing n fields of view, wherein the larger n is, the better the obtained picture effect is, and generally selecting one point at intervals of 5-8 fields of view;
collecting an image: scanning a specified rectangular area view field one by using image processing software and a camera, wherein the time depends on the size of the rectangular area; the step is automatically acquired by a microscope, so that the precision is high and the time is short;
4) Data processing
And (3) microscope treatment: taking inclusions in any view field, setting the gray level of the inclusions according to the types of the inclusions, particularly removing the influence of pollutants, and obtaining the levels, the lengths, the widths and the areas of different inclusions;
manual treatment: in order to remove the influence of pollutants on the quantitative analysis of the inclusion, the inclusion in a visual field is screened manually; and calculating the grade, length, width, area and other parameters of the inclusions according to the requirements, so as to meet the requirements of quantitative analysis.
Further, the sample size is: 20mm × 20mm.
Further, the metallographic microscope is an olympus GX53 metallographic microscope.
Further, OLYMPUS Stream image analysis software and a CCD camera were used.
Compared with the prior art, the invention has the beneficial technical effects that:
the invention provides a quantitative analysis method for the purity of heavy rail steel, which is used for quantitatively analyzing inclusions in a target area by using a full-automatic microscope, evaluating the purity of the heavy rail steel and effectively monitoring the distribution of the inclusions and the condition of damaging steel.
Drawings
The invention is further illustrated in the following description with reference to the drawings.
FIG. 1 shows the results of computer quantitative analysis.
FIG. 2 is a topographical view of contaminants within an inspection field.
Detailed Description
Examples
The U71Mn produced in 7 months in 2021 has frequent nuclear injury, and nonmetallic inclusions can be found in a nuclear injury source region. In order to compare the inclusion level of the steel rail produced in 7 months with that of the previous steel rail (produced in 5 months), samples are respectively taken from the lower part of a tread of the rail head, and metallographic phase sample preparation and microscope detection analysis are carried out. The production steel rail in the month of 5 is numbered as 5#, and the production steel rail in the month of 7 is numbered as 7#. The longitudinal surfaces of No. 5 and No. 7 are detected, and the detection area is about300mm 2 The results of the grading of nonmetallic inclusions according to GB/T10561-2005 are shown in Table 1.
TABLE 1.5# and 7# inclusions rating results
As can be seen from the results in Table 1, the grades of 5# and 7# inclusions do not differ much, and in order to further study the distribution of inclusions, the detailed study was carried out on the samples using the method of the present invention: a rectangular region of 17mm × 12mm =204mm2 was set with the zero position of 8mm below the tread, and a 100-fold objective lens was used. 12 points are selected at intervals in the set rectangular area and sequentially focused to make the focal planes of adjacent fields approximately the same. Scanning was started by using a semi-automatic microscope, and as a result, as shown in fig. 1, the length, width and area of different inclusions can be seen, and 374 fields of view are collected in total. Manual screening, where suspected contaminants are found, is included in the calculation, as indicated by the circle in fig. 2. Therefore, the results of the manual statistical calculation of the inclusions of the types B and C with high steel base destructiveness are shown in Table 2. The number of 5# B and C type inclusions with the grade no more than 1 is 25+3+2=30, and the number of 7# B and C type inclusions with the grade no more than 1 is 73+13+10=96, although the grades of 5# and 7# inclusions are the same, the difference of the purity is 3 times. The steel rail nuclear damage is frequent in 7 months due to different levels of the inclusions at the same position (a nuclear damage area is easy to appear), and the importance of quantitative analysis of the inclusions is reflected.
TABLE 2 results of manual calculation
The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.
Claims (4)
1. A quantitative analysis method for the purity of heavy rail steel is characterized by comprising the following steps: the method mainly comprises the following steps:
1) Sampling
In order to research the level of inclusions in a rail region which is easy to generate nuclear damage, a sample is taken at the tread position of a rail head;
2) Metallographic specimen preparation
The detection surface is the direction in which the steel rail is rolled in parallel, chamfering by a grinding machine, coarse grinding, fine grinding by abrasive paper, and mechanical polishing are carried out, and finally, the detection surface of the test sample is a mirror surface and has no water spots or stains;
3) Microscopic examination
Setting a zero point: the prepared metallographic specimen is inversely placed on an objective table of a metallographic microscope, the position is adjusted, a certain position below a sample tread is set as a zero point, a rectangular area is set, and a 100-time objective lens is used;
setting the value of n: selecting n points at intervals in a set rectangular area, sequentially focusing n fields of view, wherein the larger n is, the better the obtained picture effect is, and generally selecting one point at intervals of 5-8 fields of view;
collecting an image: scanning a specified rectangular area view field one by using image processing software and a camera, wherein the time depends on the size of the rectangular area; the step is automatically acquired by a microscope, so that the precision is high and the time is short;
4) Data processing
And (3) microscope treatment: taking inclusions in any view field, setting the gray scale of the inclusions according to the types of the inclusions, particularly removing the influence of pollutants, and obtaining the levels, the lengths, the widths and the areas of different inclusions;
manual treatment: in order to remove the influence of pollutants on the quantitative analysis of the inclusion, the inclusion in a visual field is screened manually; and calculating the grade, length, width and area parameters of the inclusions according to the requirements, so as to meet the requirements of quantitative analysis.
2. The method for quantitatively analyzing the purity of heavy rail steel according to claim 1, wherein: the sample size was: 20mm × 20mm.
3. The method for quantitatively analyzing the purity of heavy rail steel according to claim 1, wherein: the metallographic microscope is an Olympus GX53 metallographic microscope.
4. The method for quantitatively analyzing the purity of heavy rail steel according to claim 1, wherein: OLYMPUSStream image analysis software and a CCD camera were used.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211461192.7A CN115791793A (en) | 2022-11-21 | 2022-11-21 | Quantitative analysis method for purity of heavy rail steel |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211461192.7A CN115791793A (en) | 2022-11-21 | 2022-11-21 | Quantitative analysis method for purity of heavy rail steel |
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| Publication Number | Publication Date |
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| CN115791793A true CN115791793A (en) | 2023-03-14 |
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| CN202211461192.7A Pending CN115791793A (en) | 2022-11-21 | 2022-11-21 | Quantitative analysis method for purity of heavy rail steel |
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- 2022-11-21 CN CN202211461192.7A patent/CN115791793A/en active Pending
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