JPS62188964A - Determination of phosphor concentration of phosphor segregated part - Google Patents

Abstract

PURPOSE:To enable determination of phosphor concentration of a phosphor segregated part of a sample to be inspected, by comparing a sample being inspected treated on the same testing conditions with an image processing information of a reference sample for detecting and testing phosphor segregated part. CONSTITUTION:A print sheet of a reference sample is converted to an electrical signal with an image pick up tube or the like and then into a digital signal with an A/D converter to be preserved into a memory by phosphor concentrations. On the other hand, a print sheet of a sample to be inspected is likewise converted to an electrical signal and then to a digital signal with an A/D converter and compared the resulting digital signal is with the digital signal of the reference sample previously preserved into a memory by a comparator. The results are shown on a display unit. The comparison method herein used is preferably that, first, a calibration curve of the phosphor concentration of the reference sample digitally converted is prepared and the calibration curve thus obtained is used for the sample being inspected as follows: The digital signal of the sample being inspected is compared with a digital signal corresponding to the phosphor concentration in the calibration to determine the concentration of phosphor of the sample being inspected. This enables a quick and highly accurate determination of phosphor concentration.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a method for detecting phosphorus segregated areas that quickly and easily detects the distribution state of phosphorus in metal materials such as continuously cast pieces and large steel ingots. The present invention relates to a method for quantifying phosphorus concentration using image processing information such as images.

<Prior art> Method for detecting phosphorus segregation in metal materials (Patent application 1987-170)
227), a test paper impregnated with an aqueous solution containing copper ions and nitrate ions is pasted on a metal material, the phosphorus in the test sample is occluded by the test paper, and then a coloring liquid is used to absorb the phosphorus in the test paper. Futerin segregation sites are detected by coloring phosphorus. This method can directly detect phosphorus segregation areas in large steel ingots, and does not require special detection equipment.
This method has the advantage of being easy to implement at actual work sites.

However, it is not possible to quantify the phosphorus concentration at the detection site from the detected image, and when quantifying the phosphorus concentration, the test sample itself must be measured using a device such as a macro analyzer or by a method such as ordinary quantitative chemical analysis. Must. Alternatively, for easy on-site judgment, it is only possible to estimate whether the phosphorus concentration of each part is higher or lower than the average phosphorus concentration if the average phosphorus concentration of the test sample is known.

<Object of the invention> The object of the present invention is to determine the phosphorus concentration in the phosphorus segregation area of a test sample by comparing the image processing information of the test sample and the standard sample for the phosphorus segregation area detection test conducted under the same test conditions. It provides a method for quantitative determination.

<Structure of the Invention> Like sulfur, phosphorus has a high solidification segregation rate and is significantly concentrated in the final solidified portion. On the other hand, since the phosphorous enriched portion becomes electrochemically base, the corrosion reaction proceeds preferentially in a corrosive environment. Method for detecting phosphorus segregation area (Patent application 1702/1986)
27) takes advantage of this selective corrosion of phosphorus-enriched areas and inserts copper ions between the test surface of steel materials where phosphorus is segregated and the sheet used to print the phosphorus segregation pattern. This is a method of detecting phosphorus segregation sites as blue dots or a collection of blue dots by intervening an aqueous solution containing nitrate ions and molybdate ions, and then coloring the phosphorus in the test paper blue with an aqueous solution containing molybdate ions. .

In this method, since there is a proportional relationship between the degree of coloration and the phosphorus concentration, the phosphorus concentration of the test sample can be determined from the color development state of the detected image.

However, even in the detection images obtained from the same test sample, various conditions such as the copper ion concentration and nitrate ion concentration interposed between the test surface and the sheet for printing the phosphorus segregation pattern, or the sheet attachment time, etc. Depending on the amount of light, a difference occurs in the coloring state at the same location in the detected image.

Therefore, it is not possible to quantify the phosphorus concentration in the test sample from the color development state of the detected image, and only if the average phosphorus concentration of the test sample is known, can the phosphorus concentration in each region be greater than the average phosphorus concentration? It is only possible to estimate whether it is small.

Therefore, the applicant of the present invention has conducted intensive research to solve the above-mentioned drawbacks of the prior art, and as a result has arrived at the present invention.

That is, the present invention provides a phosphorus segregation area in which the phosphorus concentration is determined in a phosphorus segregation area detection test using image processing information of a test sample and a standard sample for a phosphorus segregation area detection test conducted under the same test conditions. The present invention provides a method for quantifying phosphorus concentration.

Here, it is preferable that the image processing information is a print sheet or that the image processing information is electrical or electronic signal information obtained from the print sheet.

The present invention will be explained in more detail below.

As mentioned above, it has been confirmed that there is a correlation between the phosphorus concentration and the detected image.

However, the coloring state of the detected image depends on various conditions such as the concentration of copper ions and nitrate ions interposed between the test surface and the sheet (printed sheet) for printing the phosphorus segregation pattern, or the time for pasting the sheet. A simple comparison is not possible because of the difference in

Therefore, we focused on the fact that there is no difference in the color development of the detected images under the same detection conditions in areas with the same phosphorus concentration, and created a standard sample for the phosphorus segregation area detection test in advance, and compared the images of this and the test sample. Compare using processing information.

Image processing in the present invention refers to obtaining an image such as a printed sheet from a test sample and processing such as numerical analysis by converting this image information into electrical or electronic signal information.

(A) Preparation of standard sample for phosphorus segregation detection test The standard sample is a metal material used as a standard sample for phosphorus segregation detection test, and has a predetermined uniform phosphorus concentration.

This standard sample can be manufactured by solution treatment, precipitation treatment, etc. as disclosed in the specification of the patent application filed on the same date by the present applicant. It is desirable that the electrochemical corrosion behavior of the test sample and standard sample match. For example, ordinary steel and stainless steel have significantly different electrochemical corrosion behavior, so it is inappropriate to combine them as a test sample and a standard sample.

This standard sample is preferably one in which two or more metal materials having different phosphorus concentrations are bonded to each other.

Considering the phosphorus concentration and phosphorus segregation rate in the test sample, the phosphorus concentration level of the standard sample should be selected to cover this phosphorus concentration, but according to the phosphorus segregation detection method, it contains a phosphorus concentration of 2 wt% or more. Since it is difficult to distinguish the color development state of the detected image in the metal material used,
% or more, the quantification method of the present invention cannot be applied only to that region. The phosphorus concentration level in the standard sample needs to be at least 3 hydrates or higher, but in order to increase the particle size, 3 hydrates or higher is desirable, and if possible, Itsuki Jun or higher is better.

A test paper impregnated with an aqueous solution containing copper ions and nitrate ions was pasted on the above standard sample according to the method of Japanese Patent Application No. 170227/1982, and after the phosphorus in the standard sample was occluded by the test paper, a colored solution was applied. A print sheet is obtained by coloring the phosphorus in the test paper using

(B) Preparation of test sample For the test sample, a print sheet of standard sample C7 is similarly prepared under the same detection conditions.

(C) Compare the printed sheet of the standard sample and the printed sheet of the test sample as follows, and quantify the phosphorus concentration.

■ Visually compare the image information such as color shading of the printed sheet of the standard sample and the printed sheet of the test sample to quantify the phosphorus concentration.

In other words, the printed sheet of the test sample is compared with the printed sheet of the standard sample, and if they match, it is determined that the phosphorus concentration is the same. If they do not match, it is determined that one of the printed sheets of the test sample is It is determined that the phosphorus concentration is within a certain range, and it is estimated that the phosphorus concentration is within a certain range.

Although this method is simple, it can only accurately determine that the concentration is within a certain range, so the following method is a more accurate quantitative analysis method.

(2) Obtain optical information such as the amount of light transmission or reflection from the printed sheet of the standard sample and the printed sheet of the test sample, and compare this information to quantify the phosphorus concentration.

If optical means are used instead of visual inspection in method ① above,
Measurement particle size is improved.

■ Obtain electrical or electronic signal information from the standard sample print sheet and the test sample print sheet by optical or electrical means, and quantify the phosphorus concentration by comparing this computerized information through numerical analysis.

An example of this phosphorus concentration determination method is shown in the explanatory diagram of FIG.

The printed sheet of the standard sample is converted into an electrical signal using an image pickup tube, etc., and converted into a digital signal using an analog/digital converter, which is then stored in a storage device for each phosphorus concentration. It is converted into a signal, converted into a digital signal by an analog/digital converter, and compared with the digital signal of the standard sample previously stored in a storage device by a comparator, and the result is displayed on a display.

Preferably, the method of comparison is to create a calibration curve that is a digital signal of the phosphorus concentration of a standard sample, and compare this curve with Digital No. 19 according to the phosphorus concentration from the test sample. Determine the phosphorus concentration of the test sample.

In addition to numerical display, the display method can also be two-dimensional mapping, which corresponds to line analysis of a macro analyzer, or three-dimensional mapping.

As described above, by using electronic information, phosphorus concentration can be determined quickly and at a high particle size.

Currently, macro analyzers and the like are widely used as a mapping method for specific elements in metal materials. However, either method may pose a problem in that it is necessary to directly attach the test sample to the mapping device. For example, a test sample must be prepared from a large steel ingot to a size that can be attached to the apparatus. In this regard,
The mapping of phosphorus quantification according to the present invention does not require the test sample itself at the time of image processing, but requires a detected image.

<Example> The present invention will be specifically described below using Examples.

A. Preparation of standard sample A standard sample for the phosphorus segregation detection test is prepared using Tatami carbon steel.

After polishing the cross section of the sample with #240 emery paper, dirt on the surface to be tested was thoroughly wiped off with absorbent cotton.

On this surface, 10
A sample paper that had been soaked for a minute was crimped. After 10 minutes, the test paper was peeled off from the surface to be tested and 2 wt% ammonium molybdate-1
, 75N nitric acid aqueous solution, and 7wt% stannous chloride-3N
After each sample was immersed in an aqueous hydrochloric acid solution for 10 minutes, it was thoroughly washed with water. A printed sheet of the detected image is shown in FIG.

The image analysis device (■
Analog/
Digital conversion was performed to obtain gray level information.

At this time, two types of scanning lJ are used, and A is a wide scanning width (5 m
m), B was set as fall scan rlJ (2 mm).

The results are shown in Table 1.

B. Preparation of test sample After polishing the cut surface of the solidified and segregated part of the continuously cast slab of Nitsu carbon steel (P: 0.02wL%) with emery paper #240, the dirt on the test surface was thoroughly wiped with absorbent cotton. Ta. On this surface, 5
Test strips were crimped after being immersed in an aqueous solution containing wt% copper nitrate for 10 minutes. After 10 minutes, peel off the test paper from the surface to be tested.
After being immersed for 10 minutes in each of a 2wt% ammonium molybdate-1,75N nitric acid aqueous solution and a 7wL% stannous chloride-3N hydrochloric acid aqueous solution, it was thoroughly washed with water. A printed sheet of the detected image is shown in FIG.

That is, FIG. 1 and FIG. 2 are printed sheets of phosphorus segregation areas obtained by carrying out a phosphorus segregation area detection test under the same conditions.

Table 1 Example 1 Judging by visual inspection of Figure 2 with reference to Figure 1,
The central part of the test sample with a high degree of phosphorus segregation has a phosphorus concentration of 0.
It was found that the content was 25 wt% to 0.50 wt%.

Example 2 Furthermore, from Table 1, a calibration curve for phosphorus concentration was determined as shown in FIG.

Next, the detected image in Figure 2 was analyzed using an image analysis device (@Nireco LU).
ZEX 5000) was used to perform analog/digital conversion to obtain gray level information. The results are shown in Figure 4.

Based on the calibration curve shown in FIG. 3, the phosphorus concentration distribution of the test sample was determined from the shading level of the fourth section I.

The results are shown in Figure i5.

According to FIG. 5, the phosphorus concentration in the phosphorus segregation area of the test sample can be determined immediately, and the particle size for determining the phosphorus concentration is high.

<Effects of the Invention> According to the method of the present invention, by comparing the print sheet of the phosphorus segregation area of the standard sample with the print sheet of the two test samples, the phosphorus concentration, which could not be determined and quantified using the conventional method for detecting the phosphorus segregation area, can be determined. Now it can be quantified.

Furthermore, by comparing the print sheet of the phosphorus segregation area of the standard sample and the print sheet of the test sample using electronic information obtained from each print sheet, it is possible to quickly determine the phosphorus concentration with high particle size.

[Brief explanation of drawings]

FIG. 1 is a photograph substituted for a drawing showing a metal structure, and is a sheet of a detection image obtained by conducting a phosphorus segregation detection test on a standard sample for a phosphorus segregation detection test. FIG. 2 is a photograph substituted for a drawing showing the metallographic structure, and is a sheet of a detection image obtained by conducting a phosphorus segregation part detection test on a test sample under the same conditions as the standard sample. FIG. 3 is a graph in which the detected image of the standard sample shown in FIG. 1 is image-processed to determine the phosphor density level and a calibration curve is created. FIG. 4 is a graph obtained by processing the detected image of the test sample shown in FIG. 2 to determine the ta light level of phosphorus. FIG. 5 is a diagram showing the phosphorus concentration distribution of the test sample determined from the measured values shown in FIG. 4 using the calibration curve shown in FIG. 3. FIG. 6 is a diagram illustrating the image processing method of the present invention. F I G, , I P (mt accumulation), Do I G,, 2F
IG, 3 p (wt%) F13.4 FIG, 5

Claims (3)

[Claims] (1) In the phosphorus segregation area detection test, the phosphorus concentration in the phosphorus segregation area is quantified based on image processing information of the test sample and the standard sample for the phosphorus segregation area detection test conducted under the same test conditions. Quantification method. (2) The method for quantifying phosphorus concentration in a phosphorus segregation section according to claim 1, wherein the image processing information is a printed sheet. (3) The method for quantifying phosphorus concentration in a phosphorus segregation section according to claim 1, wherein the image processing information is electrical or electronic signal information obtained from a print sheet.