KR100439826B1 - Sample pre-treatment method adapted to oxygen and nitrogen content analysis - Google Patents

Abstract

The present invention relates to a pretreatment method of a sample for the analysis of oxygen and nitrogen content of steel and nonferrous materials, and more particularly, to obtain a sample for measuring the content of oxygen and nitrogen in steel and nonferrous materials, grinder having a diamond wheel The first step of removing impurities adhering to the surface of the material by surface treatment, and setting the surface treated material in the first step to the cutter, and then cut into a slice-shaped sample using the diamond wheel of the cutter And a third step of washing and drying the sample in the slice form in order to remove foreign substances generated in the second step.

According to the present invention, it is possible to minimize the error of the measurement results when analyzing the oxygen and nitrogen content, it is unnecessary to repeat the test by acquiring accurate measurement results can reduce the test cost, the accurate measurement results can be reflected in the material development Therefore, there is an effect that can further improve the quality of the material.

Description

Sample pre-treatment method adapted to oxygen and nitrogen content analysis

The present invention relates to a pretreatment method of a sample for the analysis of oxygen and nitrogen content of steel and nonferrous materials, and more particularly, to obtain a sample for measuring the content of oxygen and nitrogen in steel and nonferrous materials, grinder having a diamond wheel The first step of removing impurities adhering to the surface of the material by surface treatment, and setting the surface treated material in the first step to the cutter, and then cut into a slice-shaped sample using the diamond wheel of the cutter And a third step of washing and drying the sample in the slice form in order to remove foreign substances generated in the second step.

In general, the mechanical properties of steel and non-ferrous materials are changed depending on the content of oxygen and nitrogen, and therefore it is very important to measure the exact content of oxygen and nitrogen.

In the measurement of oxygen and nitrogen content, the sample is mainly analyzed by pretreatment in the form of powder or chips.

Here, the method of pretreatment of the sample in the form of a chip is described briefly. First, the material specimen is surface treated with a grinder to remove impurities such as scale and iron oxide, and then a drilling machine is drilled on the material specimen from which the impurities are removed. The sample is taken in the form of a chip using a machine, and when the collected chip is contaminated with cutting oil, it is ultrasonically cleaned with a volatile organic solvent such as alcohol, and finally dried in a drying oven to be used as an analytical sample.

However, in the above sample preparation process, a large analysis error may occur depending on the method.

In other words, the measurement of oxygen and nitrogen content in the material is analyzed in ppm unit, the powder sample has a high probability of error because the particles are fine, chip-shaped sample occupies in the crucible Large volume and large analytical errors may occur due to oxidation of the surface of the component due to overheating during drilling.

Therefore, conventionally, after pre-treatment of a sample, the analysis was repeatedly performed two or more times per sample to calculate an average value of each analysis result, and the average value was used as final data.

As a result, the conventional sample pretreatment method has problems of large analytical errors caused by the process and cost increase due to repetitive analysis of the analysis, and thus, the countermeasures are urgently required.

Therefore, the present invention has been invented to solve the above problems, it is possible to minimize the error of the measurement results when analyzing the oxygen and nitrogen content, it is unnecessary to repeat the test by obtaining accurate measurement results can reduce the test cost It is an object of the present invention to provide a method for pretreatment of a sample for analysis of oxygen and nitrogen content.

Hereinafter, the present invention will be described.

The present invention is a method for pre-treating a sample to determine the content of oxygen and nitrogen in steel and non-ferrous materials,

Surface treatment with a grinder having a diamond wheel to remove impurities adhering to the surface of the workpiece specimen;

A second step of setting the workpiece treated with the surface in the first step into a cutter and then cutting and cutting the sample into slices using the diamond wheel of the cutter;

A third step of washing and drying the sample in the form of slice to remove foreign substances generated in the second step;

Characterized in that comprises a.

In particular, in the second step, the cutting speed is maintained by cutting the diamond wheel at a rotational speed and a feed rate of 2000 to 3000 rpm and 0.04 to 0.06 mm / min, respectively.

In the second step, the surface-treated material specimens are cut into rectangular slices having a length of 2 to 3 mm in length and width.

Hereinafter, the present invention will be described in more detail.

The present invention improves the reliability of the analysis results by changing the sample pretreatment method performed before analysis from chip type sampling by drilling to slice processing using a diamond cutting wheel. The present invention relates to a method of pretreatment of a sample for analysis of oxygen and nitrogen content, which can reduce test costs.

Referring to the sample pretreatment method according to the present invention in more detail step by step as follows.

First, the first step is an impurity removal step, and surface treatment with a grinder to remove impurities such as scale and iron oxide attached to the surface of the material specimen.

At this time, the present invention is processed using a grinding wheel made of industrial diamond, not a general grinding wheel, when using a grinding wheel containing oxygen components such as aluminum oxide, the error of the analysis data due to the oxygen generated during processing There is a problem that causes.

In addition, during the processing, the rotation speed of the grinding wheel is maintained at about 1500 to 2500 rpm, preferably at 2000 rpm.

Here, when the rotation speed of the grinding wheel is faster than the above range, there is a problem of overheating.

Next, the second step is a processing step of the analytical sample, the surface specimen processed in the first step is cut into slice-shaped samples of the appropriate size using a cutter.

In this case, the cutting wheel of the cutter is also made of industrial diamond, and using the cutting wheel of the oxygen-containing material is not preferable because the error occurs largely during the analysis.

In addition, during cutting, the rotational speed and the feeding speed of the cutting wheel are maintained at 2000 to 3000 rpm and 0.04 to 0.06 mm / min, respectively. A problem arises.

In addition, in the second step, the raw material is cut into slices and processed into a sample, but the raw material is cut into rectangular slices, but the length of the horizontal and vertical lengths is 2 to 3 mm as in the following embodiments. The most accurate measurement can be obtained.

Here, when the size of the sample is large, the analysis accuracy is lowered, and when the size of the sample is small, the error range is large as in the prior art.

Finally, the third step is a washing and drying step of the analytical sample, the step of washing and drying the analyte sample obtained in the second step to remove impurities attached to the sample during cutting.

At this time, the analytical sample obtained in the second step is put in a volatile organic solvent and washed using an ultrasonic cleaner, and the washed analytical sample is dried in a drying oven to completely remove the volatile organic solvent.

As the volatile organic solvent, those commonly used in the art may be used, and as examples, methanol, ethanol or ether may be used.

The drying of the analytical sample is carried out at a temperature above the boiling point at which the volatile organic solvent can be completely removed.

Thereafter, the samples obtained through the first to third steps are stored in a desiccator.

This is to prevent the final sample from being affected by humidity and temperature, and to prevent contamination of the sample surface by the atmosphere.

In this way, in the sample pretreatment method according to the present invention, the analytical sample is cut into slices using a diamond wheel and manufactured in a square shape, thereby minimizing an analytical error when analyzing oxygen and nitrogen contents, and an error occurrence rate is increased. As a result, it is expected that the test cost can be reduced because the repeated test is unnecessary.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by Examples.

Example

Analytical samples were obtained according to the sample pretreatment method of the present invention from two types of standard specimens in which the exact contents of oxygen and nitrogen were known.

At this time, one of the standard specimens used was a standard specimen of BS37E product name provided by MBH ANALYTICAL LTD, the oxygen content of the BS37E standard specimen is 25ppm, nitrogen content is 520ppm, each error range is ± 2ppm.

On the other hand, the other one was a 501-613 standard specimen provided by LECO company, the oxygen content of this 501-613 standard specimen is 21ppm, nitrogen content is 55ppm, each error range is ± 2ppm.

First, in order to remove impurities adhering to the surfaces of the two standard specimens, the surface treatment was performed at a wheel rotation speed of 2000 rpm using a grinder equipped with a diamond grinding wheel.

Subsequently, a square sample was processed using a cutter equipped with a diamond cutting wheel at a wheel rotation speed of 2500 rpm and a cutting speed (feed speed) of 0.05 mm / min, at which time the cutter (manufacturer: STRUERS (Denmark), model name: ACCUTOM-5) ), A wheel size of 125 mm in diameter was used.

Thereafter, the sample obtained as described above was placed in a beaker filled with 500 ml of ethanol, washed for 3 minutes by an ultrasonic cleaner, and dried in a drying oven set at 80 ° C. for 10 minutes. The sample thus completed was desiccated. Was stored in the ruins.

In the embodiment of the present invention from the two standard specimens in the shape of a square having a length of 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm horizontal and vertical length three samples of each size, all 30 samples were obtained .

Comparative example

The same standard specimen as in the above example was used, and first, the surface was treated at a wheel rotation speed of 2000 rpm using a grinder equipped with a diamond wheel to remove impurities attached to the surface of each standard specimen.

Subsequently, a chip-shaped sample was taken from the surface-treated standard specimen using a drilling machine, and sizes of drill blades of 3 mm, 5 mm, and 7 mm were used.

The sample collected as described above was placed in a beaker filled with 500 ml of ethanol in the same manner as in the example, washed with an ultrasonic cleaner for 3 minutes, and then dried in a drying oven set at 80 ° C. for 10 minutes. Specimens were stored in desiccators.

In this comparative example, three samples were taken for each drill blade size (3 mm, 5 mm, and 7 mm), and 18 samples were obtained.

Experimental Example

After storing the analytical samples obtained in Examples and Comparative Examples for 2 hours in a desiccator, the content of oxygen and nitrogen was measured in ppm units, and the measurement results are shown in Tables 1 and 2 below. Respectively.

At this time, the content of oxygen and nitrogen for the samples of the Examples and Comparative Examples was carried out using an oxygen-nitrogen analyzer (Oxygen-Nitrogen Determinator, manufacturer: LECO Co., Ltd.), the same measurement conditions for each sample Applied.

When measuring the oxygen and nitrogen content by the oxygen-nitrogen analyzer, the measurement conditions are nitrogen and helium gas state ON, CO ₂ IR CELL value 7.5 ~ 9.2Volt, N ₂ TC CELL LOW value 1Volt, N ₂ TC CELL HIGH value 0.050 VOLT, oven temperature 45 ° C., helium gas pressure 40psi.

As a result of the experimental example, as shown in Table 1, in the case of analysis using the specimen obtained according to the embodiment of the present invention, the size of the specimen in both standard specimens (MBH standard specimens, LECO standard specimens) 2 In the case of ˜3 mm, the most accurate measurement can be obtained because the mean value of oxygen and nitrogen content is closest to the original content.

In addition, as shown in Table 1 and Table 2, the analysis error using the specimen obtained in the embodiment of the present invention is much more analysis error in both standard specimens than the case analyzed using the specimen obtained in the comparative example It was found to appear small.

As a result, when measuring the content of oxygen and nitrogen, when using the sample obtained by the sample pretreatment method of the present invention, the analysis error can be minimized, and accurate results can be obtained even with a single measurement. Waste of time and sample consumption can be prevented, thus reducing test costs.

As described above, the pretreatment method of the sample for oxygen and nitrogen content analysis according to the present invention, unlike the pre-treatment with a conventional chip-shaped sample was processed by cutting the analytical sample into a slice-shaped sample of the appropriate size using a diamond wheel After the pre-treatment by washing and drying, it is possible to minimize the error of the measurement results when analyzing the oxygen and nitrogen content, it is unnecessary to repeat the test due to the accurate measurement results can reduce the test cost.

In addition, since accurate measurement results can be reflected in the material development, there is an effect that can further improve the quality of the material.

Claims (3)

In the method of pre-treating a sample to determine the content of oxygen and nitrogen in steel and non-ferrous materials, Surface treatment with a grinder having a diamond wheel to remove impurities adhering to the surface of the workpiece specimen; A second step of setting the workpiece treated with the surface in the first step into a cutter and then cutting and cutting the sample into slices using the diamond wheel of the cutter; A third step of washing and drying the sample in the form of slice to remove foreign substances generated in the second step; Pretreatment method of the sample for analysis of oxygen and nitrogen content comprising a. The sample for oxygen and nitrogen content analysis according to claim 1, wherein in the second step, the diamond wheel is cut and maintained at 2000 to 3000 rpm and 0.04 to 0.06 mm / min, respectively. Pretreatment method The method of claim 1, wherein in the second step, the surface-treated material specimen is cut into rectangular slices having a length of 2 to 3 mm in length and width of the sample. Pretreatment method.