JPS582586B2 - Continuous molten metal plating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous hot-dip metal plating apparatus equipped with a foreign matter removal device for objects to be plated.

As is well known, in order to obtain a product free of surface defects in hot-dip metal plating, it is important to keep the surface of the object to be plated clean.

For this reason, continuous hot-dip metal plating equipment is equipped with a foreign matter removal device such as a scrubber device in the pretreatment process to remove foreign matter. It is also removed by equipment that does not.

For example, when passing through a gas cleaning furnace, the material to be plated and foreign matter are removed due to the difference in coefficient of thermal expansion, wind pressure caused by the gas flame, burnout, etc.; It is also removed by the blowing pressure of the temperature control device.

However, some foreign substances may not be removed even after passing through these devices, and may remain on the object to be plated.

On the other hand, as mentioned above, although the gas cleaning furnace has the function of removing foreign matter, it has the disadvantage of causing new foreign matter to adhere to the furnace.

That is, when heat reduction is performed in a gas cleaning furnace, foreign matter is separated from the object to be plated, some of which is discharged as a gas, and some of which remains in the furnace in a solid state.

The material that accumulates in the furnace later falls or is blown by the wind pressure inside the furnace, and adheres to the object to be plated.
Furthermore, it is pressed by the rolls that guide the object to be plated, making it difficult to remove it.

In addition, a part of the refractory bricks lining the gas cleaning furnace may break off, fall onto the object to be plated, and adhere to the object.

Furthermore, since the gas cleaning furnace communicates with the molten metal used for plating, the evaporated molten metal may adhere to the vicinity of the gas cleaning furnace outlet, fall off, and adhere to the object to be plated.

The foreign matter that has adhered to the object to be plated in this way is not completely removed in the pretreatment process, but on the contrary, it is newly attached in the pretreatment process.

On the other hand, conventional continuous hot-dip metal plating equipment is not equipped with a device to finally remove these foreign substances, so the object to be plated is plated with foreign substances attached.
Many surface defects such as non-plating and adhesion of foreign matter occurred.

The present invention solves the above problems by providing a foreign matter removal device that injects gas to the position immediately before the object to be plated enters the molten metal to finally remove the foreign matter adhering to the object to be plated. The present invention provides a hot dip metal plating apparatus.

Next, one embodiment of the present invention will be described.

The base of the duct-shaped snout 10 is connected to a gas cleaning furnace (not shown), and the tip thereof is immersed in the molten metal 2.

This snout 1 is inclined with respect to the surface of the molten metal 2, and a plate-shaped object 3 to be plated passes through it.

Foreign matter removal devices 4, 4a are attached to the portion of the snout 1 exposed above the surface of the molten metal 2.

The foreign matter removal devices 4 and 4a include two gas supply pipes 5 and 5a inserted into the snout 1 from the width direction of the object to be plated 30 so as to be located on both sides of the object to be plated 30, and the gas supply pipes 5 and 5a. , 5a attached to the outside of the snout 1, pressure gauges 7, 7a attached before and after these valves 6, 6a, and gas supply pipes 5, 5a inside the snout 1. a plurality of nozzles 8 installed in a row,
8a.

The nozzles 8 and 8a open radially in both edge directions from the center of the plate surface of the object 3 to be plated, and their tips face the boundary where the object 3 to be plated enters the molten metal 2.

In the continuous hot-dip metal plating apparatus equipped with the foreign matter removal devices 4, 4a configured as described above, the valves 6, 6a
When the nozzles 8 and 8a are opened and a non-oxidizing gas such as an inert gas or a reducing gas is sent, the gas is injected radially from the nozzles 8 and 8a, aiming at the boundary where the object to be plated 3 enters the molten metal 2. , the foreign matter adhering to the object to be plated 3 is blown away in the edge direction.

The gas injection pressure at this time is adjusted by referring to the pressure gauges 7, 7a installed before and after the valves 6, 6a, but the pressure on the injection side is stronger than the wind pressure inside the gas cleaning furnace. Pressure that can substantially remove attached foreign matter, i.e. 0.1 to 0.5 kg/cm2, flow rate 50 to 300
It is preferable to carry out at m3/Hr.

Further, when the foreign matter removing devices 4 and 4a are provided in this way, foreign matter floating on the surface and surface layer of the molten metal 2 can be removed.
Objects around the position where the object to be plated 3 enters the molten metal 2 are moved toward the edge of the object to be plated 3 by the pressure of the jet gas, as described above, so that fewer floating foreign substances adhere to the object to be plated 3.

The following table shows the incidence of defective products due to foreign matter adhesion when the foreign matter removal devices 4, 4a of the above embodiment are installed and when they are not installed in the production of hot-dip galvanized steel sheets. The effect is clearly visible.

As described above, the present invention blows off the foreign matter with a pressure stronger than the wind pressure in the gas cleaning furnace just before the object to be plated enters the molten metal, so it is easier to prevent the foreign matter from entering the molten metal than before. It can be cleaned and contributes to improving product quality.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a continuous hot-dip metal plating apparatus of the present invention in which a foreign matter removing device is attached, and FIG. 2 is a plan view of the foreign matter removing device. 1... Snout, 2... Molten metal, 3
...Plated object, 4, 4a... Foreign matter removal device, 5, 5a, 6.・・・Gas supply pipe, 6, 6a・
...Valve, 7,7a...Pressure gauge, 8,8
a... Nozzle.

Claims (1)

[Claims] 1. Non-oxidizing gas is injected above the surface of the molten metal within a snout that protects the plated object from oxidation in the outside air when the plate-shaped object enters the molten metal. A continuous melting metal device characterized in that a foreign matter removing device is provided in which nozzles are attached to the gas supply pipe in a row and radially from the center of the plate surface toward both edge directions, and the tips of the nozzles are directed toward the object to be plated. Plating equipment. 2. The continuous hot-dip metal plating apparatus according to claim 1, wherein the tip of the nozzle that injects the non-oxidizing gas is directed toward the boundary between the object to be plated and the molten metal.