Method for testing rapid grading of DIN 50602-inclusion K method
Technical Field
The invention belongs to the technical field of metallographic examination, and particularly relates to a DIN 50602-inclusion K method grade rapid grading examination method.
Background
As the market demand is increased, the current steel industry has increasingly K-method inspection projects for nonmetallic inclusions, German standard DIN50602 inspection is used for K-method inspection, compared with national standard GB/T10561 generally used in China, the inspection process is complex, each result reported needs to be inspected on the whole inspection surface of 6 gold-phase samples, the inspection idea is different from that of the national standard GB/T10561, GB/T10561 distinguishes the grade of strip chain-shaped inclusions (namely SS, OA and OS three types of inclusions and hereinafter called chain-shaped inclusions) by means of shape and length, spherical-shaped inclusions (namely OG spherical oxides and hereinafter called spherical inclusions) are distinguished by means of particle number, the K-method inspection defines the grade of the inclusions by means of area boundary, and the K-method inspection manpower of most of the current domestic laboratories is still weak; along with the improvement of the integral smelting level, the requirement on the purity of steel is higher and higher, the inspection of the non-metal inclusion K method is increased from 'K4' to 'K0', namely, the inclusions with smaller areas also need to be evaluated, so that the inspection difficulty of the inclusion K method is further increased; in conclusion, the inspection period of the inclusion K method is longer, 2-3 working days are occupied by one set of K4 test sample, and more K0 test samples are occupied. Therefore, the K method detection project becomes a short plate which influences the steel inspection period, and restricts the trade of export steel products to a certain extent, so that the task of trying to reduce the difficulty of the inspector in mastering the K method and improve the inspection efficiency of the inclusion K method is urgent.
Generally, according to the standard, the inclusion grading is carried out by a method of comparing the inclusion grading with a standard map when the inclusion grading is detected by a K method, but the standard map is divided into different grades according to the area of the inclusion, only a critical value picture is given, and a plurality of fields which can not be simply graded by comparing the map are inevitably encountered in actual work, so that the area calculation of the inclusion is inevitably involved, and particularly, the area calculation of the spherical inclusion usually consumes more time of an inspector. In addition, grading is performed by inspectors, and the subjective influence is large.
Disclosure of Invention
The invention provides a DIN 50602-inclusion K method grade rapid grading inspection method, aiming at reducing the difficulty of inclusion K method inspection, improving the laboratory K method inspection efficiency and shortening the K method inspection period.
In order to achieve the purpose, the invention adopts the technical scheme that: an inspection method for rapid grading of DIN 50602-inclusion K method grade, which comprises the following steps:
s1, preparing a detection sample;
s2, observing and detecting the inclusions in the sample through an optical microscope to obtain the length and width of each chain-shaped inclusion and the diameter of the spherical inclusion;
s3, inputting the length and width of each chain inclusion into a chain inclusion grading model of a corresponding type, and inputting all the diameters of the spherical inclusions into the spherical inclusion grading model, wherein each type of chain inclusion corresponds to one chain inclusion grading model;
and S4, outputting the grades of various chain inclusions and the grades of spherical inclusions in the detection sample.
Further, the chain-shaped inclusion comprises three types of inclusions including SS, OA and OS, and the construction method of the OA inclusion grading model specifically comprises the following steps:
s11, calculating the area of each OA inclusion, namely the product of the width and the length of each OA inclusion;
s12, calculating the area sum S of all OA inclusions;
and S13, calculating the difference between the sum of the areas S and the maximum area defined by each level of the OA inclusion, wherein the level corresponding to the minimum positive difference is the level of the OA inclusion in the sample.
Further, the construction method of the grading model of the OG-like spherical inclusions specifically comprises the following steps:
s21, calculating the area of each OG inclusion, namely the product of the square of the radius of the spherical inclusion and pi;
s22, calculating the area sum S of all OG inclusions;
and S23, calculating the difference between the area sum S and the maximum area defined by each level of OG inclusions, wherein the level corresponding to the minimum positive difference is the level of the spherical inclusions in the sample.
Further, after step S4, the method further includes:
and S5, calculating the comprehensive total index K of the inclusions in the sample.
Further, the construction method of the comprehensive total index K calculation model specifically comprises the following steps:
s51, counting the number of various inclusions at each level in a single detection sample view field, and multiplying the number of various inclusions by corresponding level coefficients to obtain a first intermediate sum;
s52, calculating the sum of the first intermediate sums of all the detection samples, namely the second intermediate sum S;
and S53, calculating the total area a of all the detected samples, and then obtaining the total index K of the sample inclusions, which is (S1000)/a.
Further, the preparation method of the detection sample specifically comprises the following steps:
s11, sampling: intercepting and cutting a to-be-tested sample according to standard requirements to obtain a specified number of test samples;
and S12, preparing a sample, and grinding and polishing the surface of the test sample to a mirror surface smooth state according to a metallographic method.
The invention designs the inspection method for rapidly calculating the area of the inclusion and converting the area of the inclusion into the K method level, which can effectively help metallographic phase evaluating personnel to rapidly perform the level of the inclusion in any field of view without repeatedly comparing maps, avoids the subjective influence of the detecting personnel, improves the accuracy, accelerates the detection speed, shortens the learning time of workers, improves the manpower culture efficiency, and helps a laboratory to effectively complete the K method inspection at a high speed.
Drawings
FIG. 1 is a flow chart of the test method for DIN 50602-inclusion K method grade rapid grading according to the embodiment of the invention.
Detailed Description
The following detailed description of the embodiments of the present invention will be given in order to provide those skilled in the art with a more complete, accurate and thorough understanding of the inventive concept and technical solutions of the present invention.
Fig. 1 is a flowchart of an inspection method for DIN 50602-inclusion K method grade rapid grading, according to an embodiment of the present invention, the method includes:
s1, preparing a specified number of detection samples;
in the embodiment of the present invention, the preparation method of the detection sample specifically includes the following steps:
s11, sampling: intercepting and cutting a to-be-detected sample according to standard requirements to obtain a sample, detecting and taking 6 detection samples by each set of K method according to DIN50602 standard, and if a special protocol exists, taking the content of the protocol as a standard;
s12, preparing a sample, grinding and polishing the surface of the detected sample according to a metallographic method to a mirror surface smooth state; and (3) inspecting an inspection surface (longitudinal section) parallel to the processing direction, grinding the sample by using 80#, 240#, and 1000# metallographic abrasive paper, and polishing by using 7 mu m and 2.5 mu m polishing agents and clear water to ensure that the detection surface of the detected sample achieves a smooth mirror surface and is free from contamination under a microscope so as to avoid interference on inspection accuracy.
S2, observing and detecting the inclusions in the sample through an optical microscope, and acquiring the length and the width of each chain-shaped inclusion (the maximum width of the inclusion is regarded as the width of the string (strip) -shaped inclusion) and the diameter of the spherical inclusion;
s3, inputting the length and width of each chain inclusion into a chain inclusion grading model of a corresponding type, and inputting all the diameters of the spherical inclusions into the spherical inclusion grading model, wherein each type of chain inclusion corresponds to one chain inclusion grading model;
in the embodiment of the invention, various strip chain-shaped inclusions comprise three types of inclusions including SS, OA and OS, and the construction method of the OA inclusion grading model specifically comprises the following steps:
s11, calculating the area of each OA inclusion, namely the product of the width and the length of each OA inclusion;
s12, calculating the area sum S of all OA inclusions;
and S13, calculating the difference between the sum of the areas S and the maximum area defined by each level in the chain-shaped inclusions, wherein the level corresponding to the minimum positive difference is the OA inclusion level in the sample.
In the embodiment of the invention, the method for constructing the OS inclusion grading model specifically comprises the following steps:
s21, calculating the area of each OS inclusion, namely the product of the width and the length of the OS inclusion;
s22, calculating the area sum S of all the OS inclusions;
and S23, calculating the difference between the area sum S and the maximum area defined by each level in the chain-shaped inclusions, wherein the level corresponding to the minimum positive difference is the OS inclusion level in the sample.
In the embodiment of the invention, the method for constructing the SS inclusion grading model specifically comprises the following steps:
s31, calculating the area of each SS inclusion, namely the product of the width and the length of the SS inclusion;
s32, calculating the area sum S of all SS inclusions;
and S33, calculating the difference between the area sum S and the maximum area defined by each level in the chain-shaped inclusions, wherein the level corresponding to the minimum positive difference is the SS inclusion level in the sample.
The construction method of the SS inclusion grading model and the OS inclusion grading model is the same as that of the OA inclusion grading model.
In the embodiment of the invention, the construction method of the grading model of the OG spherical inclusions specifically comprises the following steps:
s21, calculating the area of each OG inclusion, namely the product of the square of the radius of the spherical inclusion and pi;
s22, calculating the area sum S of all OG inclusions;
and S23, calculating the difference between the area sum S and the maximum area defined by each level in the OG inclusions, wherein the level corresponding to the minimum positive difference is the level of the spherical inclusions in the sample.
And S4, outputting grades of various inclusions in the detection sample by using various chain inclusion grading models and spherical inclusion grading models.
In the embodiment of the present invention, after step S4, the method further includes:
s5, calculating the comprehensive total index K of the inclusions in the sample, wherein the construction method of the comprehensive total index K calculation model comprises the following steps:
s41, counting the number of each class of inclusions in a single detection sample field, and multiplying the number by the corresponding class coefficient to sum to obtain a first intermediate sum;
s42, calculating the sum of the first intermediate sums of all the detection samples, namely the second intermediate sum S;
and S43, calculating the total area a of all the detection samples, and then integrating the total index K to (S1000)/a.
The invention designs the inspection method for rapidly calculating the area of the inclusion and converting the area of the inclusion into the K method level, which can effectively help metallographic phase evaluating personnel to rapidly perform the level of the inclusion in any field of view without repeatedly comparing maps, avoids the subjective influence of the detecting personnel, improves the accuracy, accelerates the detection speed, shortens the learning time of workers, improves the manpower culture efficiency, and helps a laboratory to effectively complete the K method inspection at a high speed.
The invention has been described above with reference to the accompanying drawings, it is obvious that the invention is not limited to the specific implementation in the above-described manner, and it is within the scope of the invention to apply the inventive concept and solution to other applications without substantial modification.