JP2776145B2 - Measuring device for coating weight of plated steel sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for providing a platinum electrode as a cathode and a sample of a plated steel sheet as an anode in an electrolytic solution contained in an electrolytic cell. This is a simple and inexpensive method for measuring the amount of plating on plated steel sheet, which can accurately measure the amount of plating without requiring extra labor. It concerns the device.

[0002]

2. Description of the Related Art Conventionally, for example, a galvanized steel plate is coated with a platinum electrode as a cathode and a specimen of a galvanized steel plate as an anode in an electrolytic solution contained in an electrolytic cell. It is measured by a device that electrochemically determines the amount of plating of a steel sheet based on Faraday's law.

FIG. 2 is a circuit diagram showing a configuration example of this type of zinc plating adhesion amount measuring apparatus. As shown in FIG. 2, an electrolytic solution (for example, a 16% caustic soda solution) is provided inside the electrolytic cell 1.
And a silver reference electrode 10 for detecting the potential of the electrolytic solution 2 and a potential difference recorder 9 ' in which the platinum electrode 3 is used as a cathode and the sample piece 4 of a galvanized steel plate is used as an anode.
, And a constant current generator 5 is connected to the platinum electrode 3 and the sample piece 4. A in the figure indicates an ammeter.

In such a zinc plating adhesion amount measuring apparatus,
As a method for measuring the amount of zinc attached, JIS standard (H
−8610). That is, FIG. 3 is a diagram showing an example of the amount of change in potential due to dissolution of zinc plating when a constant current is passed between the platinum electrode 3 and the test piece 4, and as shown in FIG. The curve shows a potential inflection point (C) when moving from the surface zinc to the alloy layer and from the alloy layer to the ground iron. From the electrolysis time to the inflection point (C) and the value of the supplied current, Based on Faraday's law,
The zinc deposition amount is calculated by the following equation.

[0005]

(Equation 1)

In this case, based on the above equation, in order to actually measure the dissolution time, a platinum electrode 3 and a test piece 2 are set in an electrolytic cell 1 and an electrolytic solution 2 is injected. At the same time as supplying the constant current I with the constant current generator 5, the measurement of the dissolution time is started with the stopwatch.

[0007] Here, at first, the indicated value of the recorder indicating the potential of the electrolytic solution 2 shows a substantially constant value. However, when the zinc layer starts to dissolve, the potential starts to rise, and when the iron base is exposed, the potential becomes low. After soaring, it reaches a maximum. At this time, the indicated value of the recorder also shows the maximum value. The stopwatch is stopped at the moment when this potential reaches the maximum value, and the dissolution time T is measured.

However, in such a measuring method,
You must wait visually until the recorder's reading reaches the maximum value.If you miss the maximum value (measurement error occurs) or press the stopwatch early, Then, there is a problem that an accurate time cannot be measured, and as a result, a correct amount of galvanized coating cannot be measured (variation in measured values due to individual differences). Further, the operator must constantly monitor the indicated value of the recorder, which requires extra labor.

On the other hand, another measuring method is, for example, “Japanese Patent Publication No. 53-5836,“ Method of measuring the weight per unit area of zinc ”.” In this measuring method, the per unit weight of zinc is determined from the amount of electricity required for dissolving zinc. Is the way.

However, in this measuring method, the operation is complicated and the electrolysis time has to be measured in order to determine the amount of electricity required for dissolving zinc, which is not only troublesome but also troublesome. There are problems such as.

Further, as another measuring method, for example, “Japanese Patent Publication No. Sho 51-6614,“ Method of measuring the amount of plating applied ””
There is. This measurement method starts counting the number of pulse signals at the same time as the start of electrolysis, and at the same time, differentiates the electrolytic voltage signal to find its inflection point, stops counting the number of pulse signals by the signal at this inflection point, and counts. This is a method of determining the amount of plating by the number of pulses. However, in this measurement method, since the inflection point is obtained by differentiating the electrolytic voltage signal, there is a problem that the apparatus is expensive and not practical.

[0012]

As described above, in the conventional measuring method, extra labor is required for the measurement, the amount of plating cannot be measured accurately, and the apparatus is complicated and expensive. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an operation capable of accurately measuring a plating adhesion amount without requiring extra labor. An object of the present invention is to provide a simple and inexpensive apparatus for measuring the amount of coating of a plated steel sheet.

[0014]

According to the present invention, in order to achieve the above-mentioned object, a platinum electrode is used as a cathode and a sample of a plated steel sheet is used as an anode in an electrolytic solution contained in an electrolytic cell. A silver reference electrode for detecting the potential of the solution is provided, and after detecting the initial potential in a state where a constant current is applied to the electrolytic cell in a device that electrochemically measures the amount of plating on the plated steel sheet based on Faraday's law A dissolving time measuring means for measuring a dissolving time until a certain time has elapsed after the potential has risen to a specified value, and a dissolving time and an energizing current value measured by the dissolving time measuring means, and the And a plating adhesion amount calculating means for calculating the plating adhesion amount dissolved therein.

[0015]

Accordingly, in the apparatus for measuring the amount of plating of a plated steel sheet according to the present invention, after a constant current is passed, a certain period of time has passed after the potential has risen from an initial value to a specified value.
Since the potential just coincides with the maximum value, after detecting the initial potential, from the melting time and the constant current value from the time when the specified voltage value is reached to the time when a certain time has passed, according to Faraday's law Based on this, the amount of galvanized coating can be automatically obtained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration example of a galvanized steel sheet adhesion measuring apparatus according to the present invention.
The same elements as those in FIG. 2 are denoted by the same reference numerals.

In FIG. 1, an electrolytic solution (for example, 16% caustic soda solution) 2 is accommodated in an electrolytic cell 1 and a platinum electrode 3 and a test piece 4 of a galvanized steel sheet are contained in the electrolytic solution 2 as shown in the figure. It is immersed in. A constant current generator 5 is connected to the platinum electrode 3 and the test piece 4, and a digital panel meter 7 is connected between the negative side of the constant current generator 5 and the platinum electrode 3 via a shunt 6. At the same time, a switch 8 is provided between the positive side of the constant current generator 5 and the test piece 2. Further, the test piece 4 is connected to one end of an input of the recorder 9, and the other end of the input of the recorder 9 is connected to a silver reference electrode 10 for detecting the potential of the electrolyte 2. Further, a program setter 11 which is a melting time measuring means for measuring a melting time is connected to a recorder 9 which is a plating adhesion amount calculating means via a switch 8. Here, the digital panel meter 7 digitally displays a constant current value to be energized, and can visually confirm the current value. The switch 8 is turned on when the measurement is started.

Furthermore, the recorder 9 generates an ALARM when the specified voltage value is reached after the measurement is started by the switch 8 and notifies it by a patrol light, and receives a signal to the REMOTE after a lapse of a predetermined time after the ALARM is generated. Has a function of calculating and recording the amount of zinc plating dissolved in the electrolytic solution 2 on the basis of the dissolution time measured by the program setter 11 and the value of the flowing current.

Further, the program setter 11
After detecting an initial potential in a state where a constant current is applied to the electrolytic cell 1, the energization time from when the potential rises to a specified voltage value until a certain time has elapsed is measured as a dissolution time. Note that the program setter 11 also has a function of turning off the power assuming that an error has occurred when the dissolution time is not measured within a predetermined time. Next, the operation of the apparatus for measuring the coating weight of a galvanized steel sheet according to the present embodiment configured as described above will be described.

In FIG. 1, in order to measure the amount of galvanized coating, a test piece 4 is attached to an electrolytic cell 1 and an electrolytic solution 2 is supplied until the silver reference electrode 10 is immersed. 11 was started to start the measurement of the dissolution time, and the current value was set by the constant current generator 5,
A constant current is supplied to the electrolytic cell 1.

Specifically, the initial potential is set to 3.99 mV, and a constant current I of 400 mA flows. Then, in this state, the zinc plating of the test piece 4 dissolves in the electrolytic solution 2 with the passage of time, but when the voltage increases by 10 mV,
That is, the potential between the silver reference electrode 10 and the test piece 4 is 13.
When the voltage reaches 99 mV, the alarm 9
Is generated, and after 0.4 seconds, a signal is received by REMOTE, and the zinc plating adhesion amount (g / m ² ) Is calculated. The dissolution time T at this time is measured by the program setter 11, and the measured value is transmitted to the recorder 9.

That is, after passing a constant current, 0.4 seconds have elapsed since the potential of the electrolyte increased 10 mV from the initial value, which coincides with the point where the voltage just shows the maximum value. This was found from experimental data. Therefore, after detecting the initial potential using the recorder 9, the galvanizing is performed based on the formula (1) based on the dissolution time from the time when the potential reaches a certain potential to the time when a certain time has elapsed, and the value of the constant current. The amount of adhesion can be determined automatically. The following table shows the results of measurements by the method of the present example (electrolytic peeling method) and the conventional method (gravimetric method).

[0023]

[Table 1]

In addition, the weight method calculation formula (since the sample is punched with a diameter of 64 mm) (weight before galvanizing melting-weight after galvanizing melting) × 100３3.2 × 3.2 × 3.14 (g) / M ² Here, 3.2 × 3.2 × 3.14 is the area of one side of a sample piece having a diameter of 64 mm.
Collected one by one.

As described above, in this embodiment, the electrolytic cell 1
A platinum electrode 3 is used as a cathode in the electrolyte solution 2 contained therein,
In addition, a silver reference electrode 10 for detecting the potential of the electrolytic solution 2 is provided using the sample piece 4 of the galvanized steel sheet as an anode, and the amount of plating on the galvanized steel sheet is electrochemically measured based on Faraday's law. After detecting the initial potential (3.99 mV) of the electrolytic solution 2 in a state where a constant current (400 mA) I is supplied to the electrolytic cell 1, the potential is adjusted to a specified value (1).
3. The program setter 11 measures the energizing time (0.4 seconds) T from the rise to 3.99 mV) to the time when a certain time has elapsed as the dissolving time, the dissolving time T measured by the program setter 11, and the energizing current. A recorder 9 for calculating and recording the amount of galvanized coating dissolved in the electrolytic solution 2 based on the value of I.

Therefore, the recorder 9 and the program setter 1
No. 1 is used, and the time when the potential reaches the maximum value is automatically measured and the amount of galvanized coating is calculated and recorded without the need for constant monitoring by the worker, that is, without extra labor. Therefore, a simple and inexpensive measuring device can be obtained.

[0027] With this, as long as the test piece 4 is attached, the amount of galvanized coating can be automatically measured thereafter, so that the dispersion of the measured values due to individual differences as in the prior art can be eliminated. Measurement errors can be eliminated, and the measurement time can be significantly reduced.

In the above embodiment, the case where only one test piece 4 is measured has been described. However, the present invention is not limited to this, and two test pieces (for measuring the back and front) or more are measured simultaneously. It is also possible to do so.

Further, in the above embodiment, the case of measuring the amount of galvanized coating has been described. However, the present invention is not limited to this, and by applying the above-described measurement principle, it is possible to simply change the mathematical formula,
The present invention can be similarly applied to the measurement of the adhesion amount of tin (Sn), an oxide film, and the like.

(Example) Surface Sn adhesion amount formula 0.61557 × (1 / A) × I × T = 0.00121 × T where 0.61557: Faraday's law A: Area (57φ) I: Peeling current (200 mA) T: Measurement time

[0031]

As described above, according to the present invention, a platinum electrode is used as a cathode in an electrolytic solution contained in an electrolytic cell,
In addition, silver reference electrodes for detecting the potential of the electrolytic solution are provided with the sample piece of the plated steel plate as the anode, and the amount of plating on the plated steel plate is electrochemically measured based on Faraday's law. After detecting the initial potential in a state where a current is applied, the dissolution time measuring means for measuring the dissolution time until a certain time has elapsed after the potential has risen to the specified value, and the dissolution time measured by the dissolution time measurement means. It is provided with a plating adhesion amount calculating means for calculating the plating adhesion amount dissolved in the electrolytic solution based on the value of the energizing current, so that the plating adhesion amount is accurately measured without requiring extra labor. It is possible to provide an inexpensive and easy-to-operate inexpensive apparatus for measuring the coating weight of a plated steel sheet.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing one embodiment of a galvanized steel sheet adhesion measuring apparatus according to the present invention.

FIG. 2 is a circuit diagram showing a configuration example of a conventional zinc plating adhesion amount measuring apparatus.

FIG. 3 is a diagram showing an example of an amount of change in potential due to dissolution of zinc plating when a constant current is passed between a platinum electrode and a test piece in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electrolysis tank, 2 ... Electrolyte, 3 ... Platinum electrode, 4 ... Test piece,
5: constant current generator, 6: current divider, 7: digital panel meter, 8: switch, 9: recorder, 10: silver reference electrode, 11: program setter.

Continuing from the front page (72) Inventor Eizou Toda 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Keiji Nakano 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Yasushi Fukushima 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Noritake Kintaka 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72 ) Inventor Hime Mada 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) G01N 27/42

Claims (1)

(57) [Claims] A platinum electrode is used as a cathode and a sample of a plated steel sheet is used as an anode in an electrolytic solution contained in an electrolytic cell.
A silver reference electrode for detecting the potential of the electrolytic solution is provided, respectively, in an apparatus for electrochemically measuring the amount of plating applied to a plated steel sheet based on Faraday's law, wherein an initial potential is applied when a constant current is applied to the electrolytic cell. After the detection, the dissolution time measuring means for measuring the dissolution time until a certain time has elapsed after the potential has risen to the specified value, the dissolution time measured by the dissolution time measurement means and the value of the energizing current And a plating adhesion amount calculating means for calculating an adhesion amount of the plating dissolved in the electrolytic solution.