JPS61295358A - Cooling method for deflector roll of metal hot dipping equipment - Google Patents

Abstract

PURPOSE:To improve quality and yield as well as to improve the shape of a plated steel sheet by introducing warm water into the inside of a deflector roll and cooling the roll surface so as to prevent occurrence of edge wave as well as sticking of metal. CONSTITUTION:Warm water is introduced into the inside of the deflector roll 1 provided above a plating path 6 of metal hot dipping equipment, by which the surface of the roll 1 is cooled uniformly, so that the sticking of plated metal of a plated steel strip 8 to the surface of the roll 1 can be prevented and, simultaneously, the occurrence of edge wave appearing at the high-temp. side (another edge) of the steel strip 8 can also be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for cooling a deflector roll of a hot-dip metal plating facility.

(Prior art) As shown in FIG. 1, the equipment for plating molten metals such as zinc and aluminum heat-treats the steel strip 8 in a plating pre-treatment furnace (not shown) and cleans the surface, and then puts it into a plating bath 6. After the plating bath 6 is guided and pulled directly upward, and the amount of adhesion is controlled by gas injection from the nozzle 7, the direction of transfer is changed by the deflector roll 1 above the plating bath 6, and the plating bath is moved within the facility.

The plated metal of the plated steel strip 8 adheres to the surface of the deflector roll 1, and this accumulates and causes scratches on the plated steel strip, so that it is difficult for the plated metal to adhere, as in, for example, Utility Model Application Publication No. 55-151863. , ceramics, carbon, and asbestos are disclosed. Furthermore, by introducing cooling water into the roll 1 to cool the roll surface, adhesion of plated metal is prevented.

Generally, in this method, cooling water at room temperature is continuously poured into one end of the roll 1 in the width direction and drawn out from the other end.
If the roll surface is cooled from the inside, for example, if the plated steel strip in contact with the roll 1 is at 300 to 400°C,
The cooling water introduced into the roll is at room temperature when it is introduced, and when it leaves the roll, the temperature is approximately 80°C.
The temperature gradient is 0.01 J°C.

This results in generation of ear waves on the high temperature side (other end) of the plated steel strip, resulting in disadvantages such as deterioration of quality.

(Problems to be Solved by the Invention) Although it is possible to prevent the adhesion of plated metal by cooling the surface of the deflector roll in this manner, it has been found that ear waves occur on the plated steel strip.

The object of the present invention is to cool the roll surface to prevent the adhesion of plated metal and to prevent the generation of such ear waves.

(Means for Solving the Problems) The present invention is characterized in that hot water is introduced into the deflector roll at the top of the plating bath of molten metal plating equipment,
A method for cooling a deflector roll of a molten metal plating equipment, which is characterized by cooling the roll surface.

That is, as mentioned above, the temperature in the width direction of the plated steel strip is about 8
There is a temperature difference of approximately 50°C between 0°C and both ends of the plated steel strip.
This difference is reduced to prevent ear waves in the plated steel strip.

However, the temperature of the plated steel strip at the deflector roll position varies slightly depending on the plated steel strip threading speed, the position of the deflector roll (distance between the plating bath and the roll), the type of plated metal, etc. Zinc plating, aluminum plating For alloy plating consisting of these as the main components and other metals, the equipment is Sendzimer type, non-oxidation furnace type continuous hot-dip plating equipment, the temperature is 250 to 400°C, and the roll surface temperature is If it is cooled to below about 100℃, there will be no adhesion of plated metal, and by keeping the temperature difference in the width direction of the plated copper strip to below about 30℃, the ear wave on the high temperature side of the plated steel strip will be ensured. It is intended to prevent

For this purpose, hot water is introduced into the deflector roll. For example, when hot water of 70 to 100°C is introduced, the minimum temperature is 70°C on the roll introduction side and the maximum temperature is 100°C on the tomoe side, and the temperature is The temperature difference is 30° C., which can reliably prevent ear waves on the plated steel strip.

Next, an example of manufacturing a container for carrying out the present invention will be given.

In FIG. 2, a water passage 2 is formed inside the deflector roll 1 as shown, a water passage hole 4a communicating with the water passage 2 is provided in the roll shaft 3 at one end of the roll 1, and a return water pipe is provided at the other end. 5 is provided with a water passage hole 4b that communicates with the water passage 2, hot water passes through the water passage 2 from the water passage hole 4a, cools the roll 1, and enters the return water pipe 5 from the water passage hole 4b to the outside of the roll 1. Discharge.

The discharged high-temperature water is led to a tank (not shown), mixed with room-temperature water, temperature-adjusted, and returned to the roll 1 from the water supply pipe 6.
Energy can be saved by supplying energy to

(Example) Next, examples of the present invention will be listed together with comparative examples.

Example 3 A 90°C hot-dip galvanized steel plate (plate thickness 0.8, zinc coating amount 1oo9/m') was cooled while introducing 80°C hot water as cooling water from one end of the deflector roll that it passed in contact with. The temperature of the hot water at the other end of the roll is 100℃.
The temperature at one end of the plated steel strip at this time was 320
°C, and the temperature at the other end was 338 °C.

The occurrence of ear waves at the other end of the plated steel strip was significantly improved in terms of steepness (ratio of wave height and distance between waves).

Comparative Example When cooling water at room temperature (22°C) was introduced from one end of the deflector roll passing under the same conditions as the example, the cooling water temperature at one end of the roll was 22°C, the cooling water temperature at the other end was 80°C,
Temperature at one end of the plated steel strip: 300℃, temperature at the other end: 355℃
It was ℃. At this time, the ear wave at the other end of the plated steel strip had a steepness of one.

(Effects of the Invention) According to the present invention, effects such as being able to keep the shape of a plated steel strip (plate) in good condition and improving quality and yield can be obtained.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a molten metal plating equipment, and FIG. 2 is an explanatory diagram showing an example of manufacturing a device for implementing the present invention.

Claims (1)

[Claims] A method for cooling a deflector roll of a molten metal plating equipment, characterized by introducing hot water into the inside of a deflector roll above a plating bath of the molten metal plating equipment to cool the roll surface.