JP2892579B2 - Method for controlling coating weight of hot-dip metal plating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the amount of deposited molten metal plating by a gas drawing method.

[0002]

2. Description of the Related Art For example, when a galvanized steel sheet is manufactured by a continuous galvanizing line, as shown in FIG.
While pulling up the plated strip 4 through the molten zinc bath 3 through the sink roll 2 provided in the pot part 1, the wiping nozzles 5, 6
The so-called gas squeezing method of adjusting the amount of galvanized coating by spraying a gas from the substrate is mainly used. That is, the zinc adhered to the surface of the strip 1 is pressed and pressed down by the jet of the wiping gas, whereby the adhered zinc is squeezed.

In controlling the amount of hot-dip galvanized coating by such a gas drawing method, for example, Japanese Patent Application Laid-Open Nos. 52-60238, 53-23830, and 3-170653 disclose such methods. This is performed by a feedforward control method using a model equation as disclosed in the official gazette. That is, in the case of JP-A-52-60238, the injection pressure of the wiping nozzles 5 and 6 is set to Pkgf / cm ² ,
Assuming that the distance between the strip 6 and the strip 4 is D mm, the strip passing speed is V mpm, and the coating weight is W g / m ² , the nozzle injection pressure P is expressed by the following equation.

P = _Ku · K ₁ (D · V / W) ^{1 / n} (1) where _Ku : feed forward characteristic correction value, K ₁ ;
Constant, n; constant. The nozzle injection pressure P in the case of JP-A-53-23830 is expressed by the following equation (2).

[0005]

(Equation 1)

Here, H: height of wiping nozzle (m
m), A, A _{1 to} A ₄ , B, B _{1 to} B ₄ , C, C ₁ to
_{C 4, D, D 1 ~D} 4, E, E 1 ~E 4; constant. Further, the nozzle injection pressure P in the case of JP-A-3-170653 is
The following equation (3) is used. P = (V · D · L 1 2 · L 2 2) / (W · lnH) 2 ............... (3) where, L _1, L _2; is a constant (correction coefficient).

[0007]

However, the deposition by the model using only the above-mentioned process variables such as the plating amount W, the wiping nozzle pressure P, the distance D between the wiping nozzle and the strip, and the passing speed V as control factors. The amount control method cannot cope with a change in the amount of adhesion with respect to a change in the temperature of the plating bath or a change in the material of the mother plate, and there is a problem in that the amount of adhesion deviates from a target. In addition, in the method of independently determining and learning only the coefficients on the front and back sides using the same model on the front and back sides of the strip, the difference between the front and back conditions of the metal reaction on the surface of the base plate in the plating bath should be fully reflected in the model. There was also a problem that it was not possible.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for controlling the amount of deposited molten metal plating, which solves the above-mentioned problems of the prior art.

[0009]

SUMMARY OF THE INVENTION The present invention provides a method for controlling the amount of plating by spraying a gas from a wiping nozzle onto the surface of a plated strip through a molten metal plating bath. Melting applying feedforward control using a feedforward control model formula composed of pressure, wiping nozzle-strip distance, and threading speed process variables
In adhesion amount control method for metal plating, added process variables of the plating bath temperature regulators of their decision depending on the metal component concentration in the plating bath with a component composition of the mother plate in plated parameters of the model formula In addition, the present invention provides a method for controlling the amount of deposited molten metal plating, characterized by further updating parameters by learning.

[0010]

The present inventor has conducted intensive studies and experiments to solve the above-mentioned problems, and as a result, has found that the following feedforward control model formula is optimal for a hot-dip galvanizing line, for example. That is, assuming that the plating bath temperature is T ° C., the plating deposition set amount W is expressed by the following equation (4).

[0011]

(Equation 2)

Here, a _1n, a _2n, a _3n, a _4n, a _{5n,
a 6n, a 7n, a 8n} , a 9n, a 10n are regression parameters, n represents corresponds to the stratification conditions. Therefore, according to the present invention, the conventional coating weight W, the wiping nozzle injection pressure P, the wiping nozzle-strip distance D, and the passing speed V, which are the control factors of the feedforward control model formula for the coating weight control, are used. The process variable of the plating bath temperature T is added to the variable as a control factor, and the parameters of the model formula are determined by regression for each of the front and back sides individually based on the operation data collected by the component concentration of the plating bath and the composition of the plating base plate, and the parameters are layered. By performing control using the condition corresponding to another condition and updating the parameter by learning, highly accurate control of the amount of plating applied can be performed according to the change of the plating bath temperature T, the type of the base plate, and the bath condition. It becomes possible.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a conceptual diagram showing an embodiment of a plating adhesion amount control device used in the present invention. In the figure, reference numeral 10 denotes a control device, which comprises a model calculation unit 11, a multilayer parameter table 12, and a parameter correction unit 13.
Further, 14 is a wiping nozzle controller, 15 is an adhesion meter, and 16 is a host computer.

[0014] First, adhesion amount target value W _S to the control device 10 from the host computer 16 is set. The process variables P, D, V, and T are detected from the plating apparatus 7 by the wiping nozzle controller 14 and output to the model calculation unit 11 and the parameter correction unit 13. On the other hand, the adhesion amount W detected by the adhesion amount meter 15 is input to the parameter correction unit 13. Then, the above (4) stored in the multilayer parameter table 12
The regression parameters a _{1n to} a _10n of the model formulas of the formulas are extracted from the two-dimensional map layered by the plating bath component concentration and the base plate composition, and set in the model calculation unit 11.
Further, based on the relationship between the adhesion amount W and the operation results, a correction parameter obtained by learning stored in the parameter correction unit 13 is set in the model calculation unit 11, and the wiping nozzle is determined based on the results of the pot unit 1 and the target adhesion amount. The injection pressure P and the wiping nozzle-strip distance D are determined and set.

Here, a supplementary explanation of the regression parameters; stratification and learning of a _{1n to} a _{10n is} as follows.
% Or less, 0.13 to 0.15%, 0.15% or more, and the base plate composition is, for example, ultra-low-carbon, low-carbon, high-tensile P, Si addition, etc., and is divided into 5 layers. Use data classified as After that, in online learning, several cases of data are accumulated for each hierarchy, and two parameters of the regression parameters, a _1n indicating the slope of the regression curve and a _10n indicating the intercept, are corrected by linear regression. .

Further, the wiping nozzles 5 and 6 of the plating apparatus 7 are provided via the wiping nozzle controller 14 in accordance with the set values of P and D output from the model calculation unit 11.
Are controlled. Hot dip galvanized steel sheet line (C
GL), the strip material of the combination (AD2 to AD4) of the Al concentration; 0.140 to 0.145%, the composition of the base plate: Fe- {C, Nb, Si, P, Ti, Mn, B} 4) Plating was performed using the equation. FIG. 2 shows the correlation characteristics of the model formula obtained by regression using stratified data having n numbers of 192 obtained at that time.

The accuracy (standard deviation σ) of the model formula of the present invention method in which the components are specified by taking in the plating bath temperature T is about 3.6 g /
m ^2, which is about 1.6 compared to the correlation characteristic σ ≒ 5.2 g / m ² of the model equation obtained by regression from single-sided data collected by the conventional method without considering the plating bath temperature T shown in FIG. It can be seen that the improvement has been achieved. Although the above embodiment has been described with reference to the case where the present invention is applied to hot-dip galvanizing, it is needless to say that the present invention is not limited to this and can be applied to alloy plating and other metal plating.

[0018]

As described above, according to the present invention,
The process variable of the plating bath temperature is incorporated as a control factor into the feedforward control model formula for controlling the coating weight of hot-dip metal plating. As a result, it is possible to greatly improve the precision of controlling the amount of applied plating, thereby saving molten metal and improving the quality of plated products.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an embodiment of a plating adhesion amount control device used in the present invention.

FIG. 2 is a characteristic diagram showing a correlation of a model when the method of the present invention is applied.

FIG. 3 is a characteristic diagram showing correlation of a model according to a conventional method.

FIG. 4 is a conceptual diagram showing a conventional example of a plating adhesion amount control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pot part 2 Sink roll 3 Hot-dip zinc bath 4 Strip 5, 6 Wiping nozzle 7 Plating device 10 Controller 11 Model calculation part 12 Multi-layer parameter table 13 Parameter correction part 14 Wiping nozzle controller 15 Adhesion meter 16 High-order computer

Claims (1)

(57) [Claims] When a gas is blown from a wiping nozzle to a surface of a plated strip passing through a molten metal plating bath to control a coating weight, a coating weight, a wiping nozzle injection pressure, a distance between a wiping nozzle and a strip. , Fidofu with configured feedforward control model equation for each process variable strip running speed
Method for controlling the coating weight of hot-dip metal plating applying forward control
In law, added process variables of the plating bath temperature regulators of their, determined according to the metal component concentration of the component composition and the plating bath of the mother plate in plated parameters of the model equation, the more learning parameters A method for controlling the amount of coating of hot-dip metal plating, characterized in that