JPS644836Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a continuous molten metal plating apparatus.

In recent years, the demand for surface-treated steel sheets has increased, and in order to efficiently manufacture them, steel strips are surface-treated using continuous hot-dip metal plating equipment. FIG. 1 shows an example of the above continuous molten metal plating apparatus for carrying out hot dip galvanizing. In the figure, a steel strip 1 is passed through a snout and charged into a molten Zn bath filled in a tank 11 after undergoing a heat treatment process.
Here, the steel strip 1 is connected to the sink roll 12
A pair of coating rolls 2,
2. The gas is continuously drawn upward through a pair of gas throttle devices 13, 13 above the bath. The coating rolls 2, 2 are mainly supplied with gas (air,
This is provided to prevent the steel strip 1 from becoming deflected when adjusting the galvanizing thickness on one side of the steel strip by injecting combustion waste gas, etc.).
The coating rolls 2, 2 also have the role of adjusting the tension of the steel strip 1 by being equipped with a drive mechanism.

However, the bath surface 14 is exposed to the atmosphere, and if the gas from the gas throttle devices 13, 13 is oxidizing, the molten zinc is easily oxidized to zinc oxide, which is different from mere dross in the bath. They float on the bath surface 14 as different so-called top loss 15 (floating foreign matter on the bath surface). If this dross 15 adheres to the surface of the steel strip 1, it not only damages the appearance but also has a negative effect on corrosion resistance. Therefore, from the viewpoint of maintaining a constant product quality, such dross 15
It is necessary to strictly control the adhesion of

Conventionally, the dross 15 was scooped up and removed by hand, but recent advances in operating technology and equipment technology have made it possible to operate at high speeds. However, a problem arises in that the amount of dross 15 generated on the bath surface 14 increases, and it has become impossible to remove the dross by hand.

In addition, when the dross 15 is scooped up by a mechanical device instead of manually, devices such as gas squeezing devices 13, coating rolls 2, 2, etc. are installed at the rising part of the steel strip 1, as shown in FIG. Currently, there is no space to install a device to scoop up the dross 15.

The present invention has been made to solve the above problems, and therefore, the present invention provides a pair of coating rolls that contact the steel strip and have rotating vanes coaxially with each other, and these are installed in the bath near the bath surface,
The basic feature of this method is that the rotating blades rotate together with the rotation of the coating roll. The rotation of the rotating blades creates a flow of molten metal on the bath surface, and causes the dross on the bath surface to flow outward from both sides of the steel strip without entraining air, thereby moving and removing the dross.

Hereinafter, specific embodiments of the present invention will be described based on the drawings.

The plating apparatus according to the present invention uses coating rolls 2, 2, like the conventional plating apparatus shown in FIG. 1, to continuously apply molten metal to the surface of the steel strip 1 and perform the plating process. In the present embodiment, as shown in FIG. 2 in the above plating apparatus, rotating blades 4 are provided coaxially with each axis 3 of the coating rolls 2, 2 used therein, and
These are installed in the bath near the bath surface 14. Further, these rotating blades 4, 4 are adapted to rotate in opposite directions as the coating rolls 2, 2 rotate.

As shown in FIG.
installed on. Further, as shown in FIG. 2 and FIG. 3 showing the side surface thereof, the rotary blade 4 is screw-shaped and is composed of four spiral blades 40 provided around the roll shaft end 31. has been done. Here coating roll 2,2
is driven by a drive mechanism such as a motor, and the rotating blade 4 is also rotated at the same time.
The rotation of the molten metal generates a flow of molten metal on the bath surface 14.

In addition to the above configuration, it is more effective to provide an inclined groove 21 on the body surface 20 of the coating roll 2 as shown in FIG. That is, by providing the inclined grooves 21 on the surface of the roll 2 and rotating the roll 2, it is also possible to generate a molten metal flow on the bath surface 14. In this case, the inclined groove 21 can have its inclined direction reversed or symmetrical with respect to the center of the roll 2 cylinder by setting the flow direction of the molten metal.

In the plating apparatus according to the embodiments described above,
The coating rolls 2, 2 rotate in contact with the surface of the steel strip 1 as it passes upward in the direction of the bath surface 14, and apply tension to the steel strip 1 so that it does not bend. When the coating rolls 2, 2 rotate, the rotating blades 4, 4 provided coaxially also rotate together. Then, the rotation of the rotary vanes 4, 4 generates a molten metal flow on the bath surface 14 that flows in the respective rotational directions. Since the molten metal flow generated on the bath surface is directed away from the steel strip 1 on both sides of the steel strip 1, the molten metal flow floats onto the bath surface 14 and clings to the rising portion of the strip. The top dross 15 that are present can be swept away in one direction without involving air. Therefore, the dross 15 does not adhere to the surface of the steel strip 1, and the swept away dross 15 can be removed by a scooping device or the like at another location where there is sufficient space.

According to the continuous molten metal plating apparatus of the present invention having the above-mentioned configuration, the rotary blades that rotate together with the pair of coating rolls generate molten metal flows on the bath surface that mutually flow in directions away from the steel strip. It has the excellent effect of washing away the top dross, which prevents the dross from adhering to the steel strip emerging from the bath surface.
As a result, the appearance of the surface-treated strip is not impaired and corrosion resistance is also improved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional continuous molten metal plating apparatus, FIG. 2 is a partially enlarged view of a coating roll used in a plating apparatus according to an embodiment of the present invention, and FIG. 3 is a side view of the coating roll. FIG. 4 is an explanatory diagram when grooves are provided on the surface of the coating roll of the above embodiment. In the figure, 1 is a steel strip, 2 is a coating roll, 3 is a shaft, 4 is a rotating blade, and 14 is a bath surface.

Claims (1)

[Scope of utility model registration request] In a continuous molten metal plating apparatus that coats a steel strip with molten metal using a pair of coating rolls that are in contact with both sides of the steel strip, rotating blades are provided coaxially with the coating roll axis, and these are placed near the bath surface. 1. A continuous molten metal plating apparatus, characterized in that the continuous molten metal plating apparatus is installed in a bath, and the rotating blades rotate together with the rotation of the coating roll.