【発明の詳細な説明】[Detailed description of the invention]
この発明は、連続メツキラインにおいて化成処
理皮膜付着量のオンライン計測を行なう方法に関
するものである。
電気ブリキは、耐錆性、塗油密着性等の向上を
計るために、錫メツキの表面に電解クロム酸処理
法により化成処理皮膜と称される極薄メツキがほ
どこされる。そして、この処理によつて生成され
る該皮膜厚みは、耐錆性、塗料密着性、ハンダ性
等の理由からある一定量に管理されなければなら
ない。このため、従来からオンラインで採取した
サンプルをオフラインで計測する方法が採用され
ていたが、結果を得るまでかなりの時間を要し、
実時間管理が極めて困難であつた。したがつて現
在ではメツキ付着量は、フアラデーの法則に従
い、与えられた電気量に比例するという理論に立
脚し、化成処理皮膜付着量Ｃcrを(1)式に示す様に
各パス電流値の総和
The present invention relates to a method for online measurement of the amount of a chemical conversion coating deposited on a continuous plating line. In order to improve rust resistance, oil adhesion, etc. of electric tinplate, an ultra-thin plating called a chemical conversion coating is applied to the tin plated surface by electrolytic chromic acid treatment. The thickness of the film produced by this treatment must be controlled to a certain level for reasons such as rust resistance, paint adhesion, and solderability. For this reason, conventional methods have been adopted in which samples collected online are measured offline, but it takes a considerable amount of time to obtain results.
Real-time management was extremely difficult. Therefore, based on the theory that the amount of plating deposited is proportional to the amount of electricity given according to Faraday's law, the amount C cr of the chemical conversion film deposited is calculated for each pass current value as shown in equation (1). sum total
【式】にライン速度計測値
Ｖlと板幅計測値Ｗlで除算した値に比例定数Ｋを
乗算して求める推定式が採用されている。
しかしながらこの方法は、求められた推定値と
実測値を比較して第１図で示すようにバラツキが
大きいため信頼性を欠き、実用的でなかつた。
この発明の目的は、連続電気メツキラインにお
ける化成処理皮膜量をオンライン実時間で高精度
に計測する方法を提供するものである。
発明者等は、オンラインにおける化成処理皮膜
付着量について調査した結果、次の事を見出し
た。(1)電解クロム酸化成処理皮膜メツキ法におい
て、メツキ槽内を通過する奇数パスと偶数パスと
ではメツキ液の鋼帯対向流速が異なるため皮膜付
着量が異なる事。(2)皮膜がメツキ槽内の重クロム
酸ソーダー等により溶解されるため、前段パスで
第２図に示すように電気量に飽和的傾向で付着し
た皮膜は、鋼板がメツキ槽内を進むにつれて減少
し、これに対し後段パスで第３図に示すように電
気量に増加傾向で付着した皮膜は、その後鋼板の
メツキ槽内を通過する回数が少ないため、皮膜厚
はあまり減少しない。換言すれば皮膜付着量は、
結果的に前段パスが後段パスより付着しにくい
事、つまり各パスにおいて化成処理皮膜付着効率
が異なる事を見出した。
本発明はこれ等の点に着目し、従来法の様に単
にメツキ電気量から皮膜量を推定するもので無
く、先ず各パス毎の電気量の指数関数を求め、そ
れを各々の皮膜付着効率に応じた係数で修正し、
しかる後にこれらの修正された値の総和を求め、
更に定数項を加算する事により、高精度に皮膜付
着量を間接的にオンライン計測する方法を提供せ
んとするものである。
この事を数式で表わすと付着量計測値Ｃcrは、
ライン速度をＶl、板幅をＷ、各パスメツキ電流
をI1〜Ｉo、各パスの付着効率定数をK1〜Ｋo、各
パスで曲線近似させるための指数定数m1〜ｍo、
無電解処理時の付着量に相当する定数をＣとし
て、(1)式で表わされる。
Ｃcr＝K1（Ｉ１／ＶｌＷ）m １＋K2（Ｉ２／ＶｌＷ）m
２
＋……Ｋo（Ｉｏ／ＶｌＷ）m ２＋Ｃ …(1)
次に実施例を参照しながら本発明を更に詳細に
説明する。第４図は前記(1)式を計算する演算装置
を示す。図で１は乗算器である。乗算器１はライ
ンを走行するメツキ鋼板の板幅Ｗとその走行速度
Ｖlとの積を求め、その積に比例する出力電圧信
号ａを発信する。２は指数計算機能付乗除算器で
ある。指数計算機能付乗除算器２は各パス毎のメ
ツキ電流計測値Ii（ｉ＝１，２……ｎ。以下同
様）を出力電流設定信号ａで除算し、これをその
パスの電流とメツキ付着量との関係式に近似させ
るためのべき乗設定器４の設定値miをべき乗算
する演算を行い、更にそのパスの電流効率を設定
するための係数設定器３の設定値Kiとの乗算を
行い、そのパスの付着量推定値を示す出力値Xi
を求める。すなわちKi（Ｉｉ／ａ）mｉ＝Xiの計算値を
求
める事になる。この様にして求められた各パス毎
のメツキ付着量出力値X1，X2……Ｘoを加算器５
に送る。加算器５は、メツキ付着量出力値X1，
X2……Ｘoの総和を求めてメツキ鋼帯が全パスを
通過した後のメツキ付着量を求め、更に全パスの
メツキ電流が零であつても若干付着するメツキ付
着量値を設定するため、定数設定器６を前記メツ
キ付着量出力値X1，X2……Ｘoの総和値と加算す
る事により最終的に化成処理皮膜量推定値Ｃcrを
算出するものである。
第６図は、本発明の実施例の主としてメツキ槽
部分を示す図である。図中、２６は第４図に示し
た演算装置であつて、これに被メツキ鋼帯２１が
メツキ浴槽２２の中で付着される皮膜付着量を推
定するために必要な、ライン速度計２３の出力値
Ｖl、板幅計２４の出力値Ｗ、および各パスのメ
ツキ陽電極２５ｉに電流供給装置より供給される
電流値を測る電流計の出力値I1〜I4、の各情報が
入力され、前記説明した通りの方法でメツキ付着
量推定値Ｃcrを得る。なお被メツキ鋼帯２１が電
極２５１，２５２……を通る各工程が第１，第２
……パスである。
ところで、(1)式中の各係数値K1，K2……Ｋo、
各指定値m1，m2……ｍoおよび定数値Ｃの設定は
重要であり、発明者等は、これ等の値を得るため
に実在の電気メツキラインにおいて各パスの電流
値、ライン速度値、板幅値を記録し、かつその時
の皮膜量をオフラインで求め、皮膜量を従属変数
とし、各パス毎のメツキ電流値とライン速度値お
よび板幅値とより求めた各パルス毎の電気量値
に、各パス毎にm1，m2……ｍoなる指数計算を行
つた値を独立変数とし、重回帰分析と主とする解
析を行い、
K1＝0.002，K2＝0.314，K3＝0.412，K4＝
133.79，Ｃ＝0.102，m1＝0.1，m2＝0.2，m3＝
0.1，m4＝2.0
という結果を得た。従つて(1)式にこれ等の値を代
入すると、皮膜推定量Ｃcrは
Ｃcr≒
0.314（Ｉ２／ＶｌＷ）0.2＋0.412（Ｉ３／ＶｌＷ
）0.1
＋133.79（Ｉ４／ＶｌＷ）2.0＋0.102 ……(2)
と表わす事が出来る。
発明者等は、重クロム酸ソーダー陰極電解処理
の化学メツキ処理条件下で、通板した時の１〜４
パス、メツキ電流Ｉ1〜4、およびラインスピード
Ｖl、板幅Ｗを(2)式に代入し、推定された付着量
Ｃcrと正確な付着量との対比を採り、第５図に示
す様な好結果を得る事が出来、本法が従来法に比
して優れている事を証明した。
以上の様に、本発明によれば、比較的簡単な方
法によりオンライン実時間で高精度に化成処理皮
膜付着量を計測する事が出来る。An estimation formula is adopted in which the value obtained by dividing [Formula] by the line speed measurement value V l and the plate width measurement value W l is multiplied by a proportionality constant K. However, this method lacks reliability and is not practical because the obtained estimated values and actual measured values are compared and there are large variations as shown in FIG. An object of the present invention is to provide a method for measuring the amount of a chemical conversion coating in a continuous electroplating line with high precision online in real time. The inventors conducted an online investigation on the amount of chemical conversion film deposited and found the following. (1) In the electrolytic chromium oxidation treatment film plating method, the amount of film deposited differs between the odd-numbered passes and even-numbered passes through the plating tank because the flow velocity of the plating solution across the steel strip is different. (2) Because the film is dissolved by sodium dichromate, etc. in the plating tank, the film that adhered in the previous pass with a tendency to saturate the amount of electricity as shown in Figure 2 will disappear as the steel plate advances through the plating tank. On the other hand, as shown in FIG. 3, the film deposited in the latter pass has a tendency to increase in electricity quantity, and since the number of subsequent passes through the steel plate plating bath is small, the film thickness does not decrease much. In other words, the amount of film attached is
As a result, it was found that the former pass was less likely to adhere than the latter pass, that is, the chemical conversion film adhesion efficiency was different in each pass. The present invention focuses on these points, and instead of simply estimating the amount of film from the amount of plating electricity as in the conventional method, it first calculates the exponential function of the amount of electricity for each pass, and then calculates the exponential function of the amount of electricity for each pass. Correct it with a coefficient according to
After that, calculate the sum of these corrected values,
Furthermore, by adding a constant term, the present invention aims to provide a method for indirectly measuring the film adhesion amount on-line with high accuracy. Expressing this mathematically, the measured adhesion amount C cr is:
The line speed is V l , the plate width is W, each pass plating current is I 1 to I o , the adhesion efficiency constant of each pass is K 1 to K o , the exponential constant m 1 to m o for curve approximation in each pass,
It is expressed by equation (1), where C is a constant corresponding to the amount of adhesion during electroless treatment. C cr =K 1 (I 1 /V l W) m 1 +K 2 (I 2 /V l W) m
2 +...K o (I o /V l W) m 2 + C (1) Next, the present invention will be explained in more detail with reference to Examples. FIG. 4 shows an arithmetic device that calculates the above equation (1). In the figure, 1 is a multiplier. Multiplier 1 calculates the product of the plate width W of the galvanized steel plate running on the line and its running speed V l , and outputs an output voltage signal a proportional to the product. 2 is a multiplier/divider with an exponential calculation function. The multiplier/divider 2 with an exponential calculation function divides the plating current measurement value Ii (i=1, 2...n, the same applies hereinafter) for each pass by the output current setting signal a, and divides this into the current of that path and the plating adhesion. The set value mi of the power setter 4 is multiplied by a power in order to approximate the relational expression with the quantity, and the set value Ki of the coefficient setter 3 is further multiplied to set the current efficiency of the path. , an output value Xi indicating the estimated amount of adhesion for that path
seek. In other words, the calculated value of Ki (Ii/a) m i=Xi is obtained. The plating adhesion amount output values X 1 , X 2 . . .
send to The adder 5 outputs the plating adhesion amount output value X 1 ,
X 2 ...Calculate the total sum of X o to determine the amount of plating deposited after the plated steel strip has passed through all passes, and further set the value of the amount of plating that will adhere slightly even if the plating current of all passes is zero. Therefore, the estimated value C cr of the amount of chemical conversion coating is finally calculated by adding the constant setting device 6 to the total value of the plating adhesion amount output values X 1 , X 2 . . . X o . FIG. 6 is a diagram mainly showing the plating tank portion of the embodiment of the present invention. In the figure, reference numeral 26 is the arithmetic unit shown in FIG. The following information is input: the output value V l , the output value W of the plate width meter 24, and the output values I 1 to I 4 of the ammeter that measures the current value supplied from the current supply device to the plating positive electrode 25i of each pass. Then, the estimated plating amount C cr is obtained in the same manner as explained above. Note that each process in which the steel strip 21 to be plated passes through the electrodes 25 1 , 25 2 . . .
...It's a pass. By the way, each coefficient value K 1 , K 2 ...K o in equation (1),
The settings of each specified value m 1 , m 2 ...m o and constant value C are important, and in order to obtain these values, the inventors set the current value and line speed value of each path in an actual electroplating line. , the sheet width value is recorded, and the amount of coating at that time is determined off-line, the amount of coating is taken as a dependent variable, and the amount of electricity for each pulse is determined from the plating current value, line speed value, and sheet width value for each pass. Using the values obtained by performing an index calculation of m 1 , m 2 . 3 = 0.412, K 4 =
133.79, C=0.102, m 1 = 0.1, m 2 = 0.2, m 3 =
The result was 0.1, m 4 = 2.0. Therefore, by substituting these values into equation (1), the film estimation amount C cr is C cr ≈ 0.314 (I 2 /V l W) 0.2 + 0.412 (I 3 /V l W
) 0.1 +133.79 (I 4 /V l W) 2.0 +0.102 ...(2) It can be expressed as. The inventors have determined that 1 to 4 when the plate is passed under the chemical plating treatment conditions of sodium dichromate cathode electrolysis treatment.
By substituting the path, plating current I 1 to 4 , line speed V l , and plate width W into equation (2), the estimated adhesion amount C cr was compared with the accurate adhesion amount, as shown in Figure 5. We were able to obtain various good results, proving that this method is superior to conventional methods. As described above, according to the present invention, the amount of chemical conversion film deposited can be measured with high precision online in real time using a relatively simple method.
【図面の簡単な説明】[Brief explanation of the drawing]
第１図は従来法による皮膜付着量の推定値と実
測値との関係を示すグラフ、第２図および第３図
は前段および後段各パスの皮膜付着状態を示すグ
ラフ、第４図は本発明の実施例の演算部を示すブ
ロツク図、第５図は本発明の効果を示すグラフ、
第６図は本発明の実施例の主としてメツキ槽部分
を示す説明図である。
図面で、２２はメツキ浴槽、２５１，２５２…
…は各パスの電極、２１は被メツキ鋼帯である。
Figure 1 is a graph showing the relationship between the estimated value and actual measurement of the film adhesion amount by the conventional method, Figures 2 and 3 are graphs showing the film adhesion state in each pass of the first and second stages, and Figure 4 is the graph of the present invention. FIG. 5 is a block diagram showing the calculation unit of the embodiment, and FIG. 5 is a graph showing the effects of the present invention.
FIG. 6 is an explanatory diagram mainly showing the plating tank portion of the embodiment of the present invention. In the drawing, 22 is a bathtub, 25 1 , 25 2 ...
... is an electrode for each pass, and 21 is a steel strip to be plated.