KR100325341B1 - Method for measuring thickness of coated layer in non-directional electric steel - Google Patents

Abstract

PURPOSE: A measuring method of a thickness of a coated layer in a non-directional electric steel is provided to measure the thickness of insulated film layer by easily measuring a Fe peak convergence time of a GDS(Glow Discharge Spectrometer). CONSTITUTION: A Fe peak convergence time is measured by a GDS. The thickness of a standard sample is measured with using a scanning microscope by producing the standard sample according to the composition of resin. An inclination is measured by plotting the measured thickness and the Fe peak convergence time. The thickness of a coated layer is calculated by multiplying the inclination by the Fe peak convergence time. Thereby, the Fe peak convergence time is measured easily, quickly and exactly.

Description

Coating layer thickness measurement method of non-oriented electrical steel sheet

The present invention relates to a method for measuring the thickness of an insulating coating layer coated on both surfaces of a non-oriented electrical steel sheet.

In general, since non-oriented electrical steel sheet requires characteristics such as insulation, corrosion resistance, and workability, inorganic or non-machined coating liquid is applied to the surface of electrical steel sheet.

The coating solution generally contains components such as colloidal silica, Ca- or Mg-Chromate, resin, and the like. According to these compositions, various characteristics, such as stability of a solution, applicability | paintability, and a color, change. Drying is performed after the application using a roll coater to form a solid insulating film.

The thickness of the insulating film thus formed has a great influence on insulation, corrosion resistance, surface appearance and weldability after processing. In order to control these properties required in the actual product of electrical steel sheet, the thickness of the insulating film should be adjusted, and there is a need to accurately evaluate the thickness of the coating layer after the working process.

The thickness of insulation coating layer of non-oriented electrical steel sheet of real product is generally very thin film in the range of 0.3-0.8μm, and it is not easy to measure these values accurately, and the thickness control of the work process depends on the operator's experience. .

In the conventional coating measurement, the contact coating method is a method which is calculated by contacting a needle-shaped probe with a coating layer to detect a difference in electrical conductivity of the coating layer.

However, in the electrical steel sheet, errors due to the measurement site appear largely due to uneven deposition of some compositions, uneven film formation, and the influence of surface roughness of the steel sheet. In order to accurately measure the thickness, it is more accurate to mold the cross section of the electrical steel sheet and observe it with a scanning microscope (SEM) device.

However, in order to measure the scanning microscope, specimen preparation and observation cross-section processing are required, and a long time is required.

According to the present invention, after preparing an insulating coated standard specimens, the Fe peak convergence time of the standard specimens was measured, and the thicknesses of the specimens were measured using a scanning microscope. The convergence time and scanning microscope of the Fe peaks in a spectrometer were measured. Coating of non-oriented electrical steel sheet by defining the film thickness relation of the film thickness, which is faster, more accurate, and easier to measure the Fe peak convergence time of the spectrometer, and the thickness of the insulating film layer can be measured by the formula. The purpose is to provide a thickness measurement method.

The present invention having the above object is to measure the Fe peak (peak) convergence time with a spectrophotometer, to prepare a standard specimen according to the composition of the resin to measure the thickness of the standard specimen using a scanning microscope, and the measurement Plotting the measured thickness and Fe peak convergence time (plot) to measure the slope and the thickness of the coating layer is characterized by consisting of the step of obtaining the slope x Fe peak convergence time.

Figure 1 (a)-(e) is a graph showing the component changes according to the thickness of the insulating film by the spectrometer measured in the present invention

2 is a graph showing the convergence time of the Fe peak of the spectrometer according to the change in the thickness of the insulating film according to the present invention

The present invention is to measure the thickness of the Fe peak convergence time with a spectrophotometer in measuring the insulation film thickness of the non-oriented electrical steel sheet, and to prepare a standard specimen according to the composition of the resin to the thickness of the standard specimen using a scanning microscope Measuring the step, and plotting the measured thickness and the Fe feed convergence time (plot) to measure the slope, and the thickness of the coating layer is composed of the step of obtaining the slope x Fe peak convergence time.

The operation of the present invention configured as described above is as follows.

In the present invention, a GDS (Glow Disharge Spectrometer), which is a spectrometer capable of profile depth, was used.

First, standard specimens prepared with an insulating coating were prepared using a coating solution mixed and synthesized in a specific composition such as colloidal silica, Mg-chromate, and resin. Standard specimens were prepared by coating a specific composition of insulating coating solution on an electrical steel sheet 0 times, 2 times, 4 times, 6 times, 8 times, and drying it for 15 seconds at around 650 ° C to form an insulating film on the electrical steel sheet.

Here, the four coated steel sheets were cut to 1 × 1 cm and molded with acrylic resin so that the cross section was in the direction of observation for scanning microscope observation. The measured thickness of the film cross section by the scanning microscope is shown in Table 1 below.

In the spectrophotometer measurement, the steel sheet and the coated four-layer specimens were measured under constant conditions such as temperature, vacuum degree, current, voltage, and measurement area (φ4 mm).

The detection intensity contribution of each element was defined as a standard measurement condition so that it could be easily distinguished from the result graph. The spectroscopy results of the standard specimens under these conditions are shown in FIG. 1.

As can be seen in Figure 1 (a) it can be seen that in the non-coated base steel sheet, the time change of the Fe peak increases rapidly from the beginning and has a certain strength.

1 (b) is coated twice, the convergence of Fe peaks starts after the measurement time of 19 seconds and the peaks of Si, Cr, Mg, O, C, etc. are observed to decrease as the steel sheet appears.

In Fig. 1 (c), the peak pattern of element detection is similar to that of Fig. 1 (b), but the time taken to converge the Fe peak is longer than that of Fig. 1 (b).

It can be seen that the Fe peak convergence time of FIGS. 1 (d) and 1 (e) becomes longer in order. As described above, as the number of coatings, that is, the thickness of the coating layer increases, the time taken for convergence of the Fe peak becomes long, and it is found that there is a proportional relationship.

Fig. 2 shows the relationship between the thickness of the insulation film observed on the scanning microscopes of five standard specimens and the convergence time of the Fe peaks in the analytical analyzer.

As can be seen in Figure 2 the thickness of the coating layer (T / μm) = 0.0199 x Fe peak convergence time (t / sec) -------- Formula (1)

It was found that there is a relationship. In the coating thickness of the coated steel sheet coated with a coating solution, a standard specimen of the coating was prepared, the thickness thereof was measured by a scanning microscope, and time was measured using an analytical analyzer to determine the relationship between thickness and time.

Since the coating layer thickness management of the actual product can be measured quickly, precisely and easily by measuring the convergence time of the Fe peak by analytical analyzer measurement.

TABLE 1Thickness by Scanning Microscope of Standard Specimen and Fe Peak Convergence Time by Specimen Analyzer

Example

The thickness of the actual product after a work process was measured using Formula (1) prescribed | regulated by this invention. The composition of the standard solution and the coating solution used in the product are identical. Fe peak convergence time of the product was measured using the conditions of the standard specimen spectrometer measurement. Using the formula (1), the measured time was able to easily define the thickness of the insulating film layer of the product as shown in Table 2 below.

TABLE 2

The present invention as described above is to measure the convergence time of the Fe peak of the standard specimen after preparing the insulating specimen treated standard specimens and then measure the thickness of these specimens using a scanning microscope. By defining the relationship between the Fe peak convergence time and the film thickness of the scanning microscope in the spectrometer, the Fe peak convergence time of the spectrometer can be measured more quickly, accurately and easily than the conventional contact measurement method. There is a measurable effect.

Claims (1)

In measuring the insulating film thickness of the non-oriented electrical steel sheet, measuring the peak peak convergence time with a spectrometer (GDS). Preparing a standard specimen according to the composition of the resin and measuring the thickness of the standard specimen using a scanning microscope. Plotting the measured thickness and Fe peak convergence time to measure a slope; The thickness of the coating layer is a coating thickness measurement method of a non-oriented electrical steel sheet, characterized in that it comprises a step of obtaining by the slope x Fe peak convergence time.

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