JPH046256A - Method for charging base metal to plating cell continuous hot dip galvanizing - Google Patents

Abstract

PURPOSE:To suppress the fluctuation in the bath level of a plating cell and the fluctuation in the temp. of a plating bath to a low level by molding base metals for hot dip galvanizing to bar coils having a circular section and continuously introducing the base metals of the amt. meeting the components in the plating cell into the plating cell. CONSTITUTION:A steel strip 3 is introduced by a sink roll 4 into the plating bath 2 in the plating cell 1 for continuous hot dip galvanizing. The steel strip 3 stuck with the plating bath 2 is perpendicularly pulled up and is taken out of the cell. One or more kinds of the zinc base metals contg. pure zinc and Al are molded to the bar-shaped base metals 5a (or plate base metals 5b). These base metals are previously coiled on reels and the coils are mounted on un-coilers 8. The base metals 5a of the amt. meeting the components of the plating bath 2 are continuously and successively introduced by feed rolls 9 into the plating bath 2 according to the decrease of the plating bath 2 by the progression of the plating operation. The level and temp. of the plating bath 2 are maintained nearly constant in this way and the zinc base metals are easily and safely replenished.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for charging ingot into a plating tank for continuous hot-dip galvanizing.

[Prior Art] As shown in FIG. 4, continuous hot-dip galvanizing is performed by filling a box-shaped hot-dip galvanizing tank 21 with a plating bath 22 containing melted plating metal, and continuously coating a steel strip 24 through a zinc roll 23. introduce the plating bath 22 to both sides of the steel strip 24,
This is done by vertically pulling up the steel strip 24 to which the plating bath 22 has adhered.

Among the above-mentioned continuous hot-dip galvanizing equipment, in large-scale plating equipment, the size of the ingot of zinc metal to be melted is about 2 tons.

[Problems to be Solved by the Invention] The above-described conventional method of charging metal into a plating tank for continuous hot-dip galvanizing has the following problems. That is,
When two tons of ingots are put into the plating tank, the surface of the plating bath rises rapidly, and impurities such as dross that have adhered to the tank walls and near the bath surface of equipment immersed in the plating tank are deposited into the plating tank. As the cleanliness of the plating bath decreases, impurities such as dross adhere to the surface of the copper strip during plating, significantly impairing the surface quality of the plated steel strip. The temperature of the plating bath was 10°C lower than normal, and the specified plating thickness could not be achieved in some areas. It was lit.

In addition to pure zinc plating, the range of zinc plating includes 3
．． 5%AJ zinc plating, 5%AJ zinc plating, 10%A
There are zinc platings containing respective percentages of Aρ, such as J zinc plating and 55% Aρ zinc plating. In the case of zinc plating containing AJ, it is necessary to adjust the components of the plating bath, but at this time it is necessary to frequently add small chunks of plating metal, which requires a lot of labor. The problem was that it would be difficult.

Furthermore, there is a problem in that splashes occur when the metal is inserted, contaminating peripheral equipment and causing burns to workers.

This invention solves the problems of the prior art as described above,
To provide a method for introducing metal into a plating tank for continuous hot-dip galvanizing that does not reduce the cleanliness of the plating bath, does not require labor, and does not contaminate peripheral equipment or cause burns to workers. The purpose is

[Means for Solving the Problems] A method for charging ingots into a plating tank for continuous hot-dip galvanizing according to the present invention includes at least one type of zinc ingots containing pure zinc and aluminum having a circular or rectangular cross section. The coil end of the strip coil is immersed in a plating bath of a hot-dip galvanizing bath, and while the coil is unwound, an amount of bare metal corresponding to the contents in the bath is continuously applied to the plating bath. This is a method of feeding ingots into a plating tank for continuous hot-dip galvanizing.

[Function] The method of charging ingots into a plating tank for continuous hot-dip galvanizing according to the present invention involves forming at least one type of zinc ingots containing pure zinc and Aρ into a strip coil with a circular or rectangular cross section. Then, the coil end of the strip coil is immersed in a plating bath made of cypress wood for hot-dip galvanizing, and as the coil is unwound, an amount of metal corresponding to the ingredients in the bath is continuously poured into the plating bath. . Since the metal is added in this way, the bath surface of the plating bath does not rise suddenly and dross adhering to the tank walls etc. is not taken into the plating bath as in the conventional method, which improves the cleanliness of the plating bath. can be kept high.

Moreover, if a coil unwinding device having a drive mechanism is employed, no labor is required for inputting the coil.

Furthermore, since a lump of metal is not thrown in, there is no risk of splashing, contaminating peripheral equipment, or causing burns.

[Example] A method of charging metal into a plating tank for continuous hot-dip galvanizing according to an example of the present invention will be explained with reference to FIGS. 1 to 3. FIG. 1 is a perspective view showing a state in which a method of charging metal into a continuous hot-dip galvanizing tank according to an embodiment of the present invention is being carried out. A plating bath 1 for continuous hot-dip galvanizing is filled with a plating bath 2, and a steel strip 3 is introduced into the plating bath 2 by a zinc roll 4. The plating bath 2 adheres to the surface of the steel strip 3 in the plating bath 1, and the steel strip 3 becomes a plated steel strip 3a and leaves the plating bath 1 in the vertical direction. In this way, the plating bath 2 is removed from the plating tank 1, so that the plating bath 2 in the plating tank 1 gradually decreases. As a method of investing bullion to supplement the decreasing amount of water,
In a method of charging ingots into a plating tank for continuous hot-dip galvanizing according to an embodiment of the present invention, the following method is adopted. That is, a plating base metal is formed into a bar-shaped base metal 5a and a plate-shaped base metal 5b shown in FIG. A bare metal coil 7a and a plate-shaped bare metal coil 7b are made, and these coils 7a or 7b are attached to a rewinding machine 8 (four in the example shown in FIG. 1), and the tip of each coil is passed through a strip feeding roll 9. The 0-strip feed roll 9 sends the bare metal strips to the plating bath while adjusting the input amount. It is a roll, and its speed can be controlled using a DC motor.

The reason why multiple coils are used is to ensure that the base metal is evenly melted throughout the plating tank 1, and in the case of A (containing zinc plating), it is possible to use coils with different Af content ratios. This is to adjust the components of the plating bath 2. Reference numeral 10 in the figure is an induction heating device for keeping the temperature of the plating bath constant and melting the base metal.

Regarding the cross-sectional dimensions of the strip forming the coil, it is considered optimal for operation to have a diameter of about 5 mm in the case of a bar, and a thickness of about 5 mm and a width of about 100 m+s in the case of a plate.

Regarding the method of determining the amount of metal input, in the case of pure zinc plating, the bath surface control method should be adopted, and in the case of aluminum-containing zinc plating, the plating bath component control method should be adopted. Using the actual bath surface level signal from the meter, the actual plating coating amount, and the planned zinc consumption per unit time calculated from the copper strip passing area per unit time (both sides), the plating bath surface is determined to be the standard. This is a method of adding zinc while adjusting the planned amount of zinc to be used. In addition, the plating bath component control method is based on the analysis value of the plating bath sample, the current bath level, the target component value, and the passing area of the steel strip per unit time.
This method determines the rate and amount of ρ-containing zinc added per unit time.

In a plating tank with a capacity of 240 tons into which metal was introduced as described above, a copper strip having a width of 610 to 122 degrees was galvanized at a line speed of 50 to 170 m/min. At this time, the bath level fluctuation of the plating bath was less than 30 mm, compared to the conventional 3 mm.
It turns out that it is more stable than 0-5oll II.

Furthermore, the temperature of the plating bath was conventionally 460 °C and 8 °C, but in the method of the present invention, it became 460 ± 2 °C, which greatly reduced the range of temperature fluctuation.

[Effects of the Invention] According to the present invention, fluctuations in the bath surface of the plating tank are reduced, and fluctuations in the temperature of the plating bath are also reduced. It is also safe, as no human effort is required to insert the bullion.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a state in which a method of charging ingots into a continuous hot-dip galvanizing tank according to an embodiment of the present invention is being carried out, and FIG. 2 is a perspective view of bar-shaped ingots and plate-shaped ingots. FIG. 3 is a perspective view of a bare metal coil, and FIG. 4 is an explanatory diagram of a general plating tank for continuous hot-dip galvanizing. 1. Plating tank, 2. Plating bath, 3. Steel strip, 4.
・Zin roll, 7a... Bar-shaped metal coil, 7b...
・Plate metal coil, 8. Rewinding machine, 9. Strip feeding roll.

Claims (1)

[Claims] At least one type of zinc ingot containing pure zinc and Al is formed into a strip coil with a circular or rectangular cross section, and the coil end of the strip coil is immersed in a plating bath of a hot-dip galvanizing bath. , A method for charging bullion into a plating tank for continuous hot-dip galvanizing, characterized by continuously charging bullion in an amount corresponding to the components in the tank while unwinding a coil.