JPH1060615A - Wire rod plating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the remarkable cost reduction as compared with the case of gaseous nitrogen by using a heat generating type atmospheric gas in which moisture is absorbed to a specified dew point as a nonoxidizing gas to be fed to the face of a plating bath in the rising part of a wire rod. SOLUTION: At the time of immersing a steel wire 1 in a galvanizing tank 2, executing galvanizing and taking up the steel wire 1 from the plating tank 2, through the gas throttling part, the bath face is covered with a nonoxidizing atmospheric gas to prevent the oxidation of the bath face, and the sticking of oxide to the wire rod 1 is prevented. As a nonoxidizing gas source therefor, the one using city gas or natural gas as the raw material, refrigerated till the dew point of <=-40 deg.C by a heat generating type gas generating device 4, and with moisture absorbed is used. Furthermore, the heat generating gas, e.g. has a compsn. composed of, by vol., 9% CO2 , 4 to 5% CO, 4 to 5% H2 and 80% N2 . In this way, easily applicable heat generating type gas can be used, by which the product capable of the remarkable reduction of the cost and moreover having a plated surface excellent in luster can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire plating apparatus of a type in which plating is drawn with a non-oxidizing gas.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional galvanizing apparatus of this kind, in which an iron wire or steel wire 1 is coated with a hot-dip galvanizing bath 2.
When dipping and pulling up, a chamber 3 surrounding the wire 1 is provided at a rising portion of the wire on the plating bath surface, and a non-oxidizing gas is supplied to the chamber 3 to prevent oxidation of the bath surface. A throttle unit 3 is provided, and a nitrogen gas is supplied from the gas source 4 that sequentially switches a plurality of nitrogen cylinders as the plating throttle gas. A plurality of gas throttles 3 are provided in parallel, and a large number of wires 1 are plated at the same time. After the wires coming out of the gas throttles 3 are cooled by a water cooling device 5, a top roller 6 is cooled. Picked up through.

[0003]

In a conventional plating apparatus, nitrogen gas is used as described above, or a hydrocarbon-based fuel gas such as propane or butane is used as a gas for plating. However, nitrogen gas usually has to be transported or stored in cylinders or tanks, so it is troublesome to handle and expensive, and fuel gas is burned at the upper opening of the gas throttle chamber. Due to the necessity of the treatment, a large amount of soot is generated, and the temperature of the wire is too high due to the flame, so that the wire is apt to droop, which is not suitable especially for thick plating. . Therefore, a first object of the present invention is to use city gas or propane gas instead of directly using a fuel gas having many defects as a restricting gas or using a method of using an expensive and cumbersome nitrogen gas. Accordingly, it is an object of the present invention to provide a wire plating apparatus of this kind that can generate an inoxidizing gas for plating squeezing at low cost.

[0004] The wire rod 1 passing through the gas throttle unit 3 is rapidly cooled by a water-cooling device 5 above. However, if water-cooling is performed before the solidification of the plating layer, the shape of the wire rod is lost and the quality deteriorates. Conventionally, heat was naturally radiated in the air from the throttle unit 3 to the water cooling device 5. However, in the case of natural heat radiation, there is a drawback that the thickness of the plating layer cannot be increased because liquid dripping easily occurs before reaching the water cooling device 5. Further, for the purpose of thick plating, a method of blowing air to the wire 1 at an intermediate portion between the gas throttle unit 3 and the water cooling device 5 has also been tried, but in this portion, the molten metal of the plating layer has not yet solidified. In addition, since air is blown in a direction intersecting with the wire 1, there is a problem that the plating layer is uneven in thickness due to the air, and the appearance of the wire is easily impaired. Therefore, a second object of the present invention is to provide a plating apparatus of this kind which can increase the plating thickness while maintaining the appearance of the wire.

[0005]

According to the first and second aspects of the present invention, as shown in FIG. 1, a non-oxidizing gas is supplied to a plating bath surface at a rising portion of a wire to prevent oxidation of the bath surface. In the wire rod plating apparatus provided with the squeezing section 3, a heat-generating atmosphere gas that has absorbed moisture until the dew point becomes -40 ° C or less is used as the non-oxidizing gas. Can continuously generate the gas for squeezing, eliminating the need for cylinders and tanks, greatly reducing costs and simplifying handling. In addition, since it has a reducing property with hydrogen gas or carbon monoxide, it is characterized in that the gloss of the plating surface can be improved.

Further, the invention according to claims 3 and 4 is a wire rod plating apparatus comprising the gas throttle section 3 and a water cooling device 5 for rapidly cooling the wire 1 above the gas throttle section 3. A forced air cooling device 8 is provided at an intermediate portion between the gas throttle unit 3 and the water cooling device 5 to cool the hot-dip coating layer of the wire to near the solidification point by an air flow parallel to the wire, so that the plating layer is not uneven in thickness. As described above, by uniformly cooling from the periphery, the fluidity of the plating layer between the plating throttle unit 3 and the water cooling device 5 is reduced, and the plating thickness can be increased without impairing the appearance. .

[0007]

FIG. 1 shows an embodiment of the present invention, in which a steel wire 1 is immersed in a hot-dip galvanizing bath 2 to perform galvanization. When the wire 1 is lifted from the plating tank 2, the bath surface is covered with a non-oxidizing atmosphere gas to prevent the bath surface from being oxidized and to prevent the oxide from adhering to the wire 1. As the non-oxidizing gas source 4, a heating type gas generator using city gas or natural gas as a raw material is provided. Note that the heat-generating atmosphere gas is an atmosphere gas obtained by burning a mixed gas having an air ratio slightly smaller than the theoretical mixing ratio, and unlike an endothermic gas obtained through heating and catalyst, without applying heat from outside. Combustion continues. In the present embodiment, the composition of the exothermic gas is, for example, CO2: 9%, CO: 4 to 5%,
H2: 4-5%, N2: 80%, frozen and absorbed until the dew point becomes -40 ° C or less, and can be produced by burning easily available city gas or propane gas. As a result, the cost can be significantly reduced, and since the drawing gas has a reducing property, a product having a much more excellent gloss on the plating surface can be obtained as compared with a method using nitrogen gas or the like. .

A water-cooling device 5 is provided above the gas narrowing section 3 for rapidly cooling the wire 1 by spraying water from both sides. The generation of wrinkles due to the temperature difference in the direction is prevented. A forced air cooling device 8 for cooling the plating layer of the wire rod to near the solidification point is provided at an intermediate portion between the gas throttle unit 3 and the water cooling device 5. The forced air cooling device 8 includes a flask-shaped pressure chamber 11 and a ventilation tube 12 connected to an upper end opening of the pressure chamber 11. The wire 1 passes through the pressure chamber 11 along a central axis. A cylinder 9 is penetrated, and a pressurized air supply pipe 10 is connected to a side wall.
A plurality of rectifying plates 13 are provided radially between the inner cylinder 9 and the outer peripheral wall at the upper end opening of the pressure chamber 11, and the air flow blown from the pressure chamber 11 into the ventilation cylinder 12 is rectified by the rectifying plate 13. The flow is rectified through the plate 13 and is uniformly cooled from the surroundings without disturbing the outer shape of the hot-dip plating layer of the wire 1 to prevent the molten metal from dripping. The lower end of the ventilation tube 12 is a screw socket, and is screwed to a screw portion on the outer periphery of the upper end of the pressure chamber 11.

[0009]

According to the first and second aspects of the present invention, a heat-generating atmosphere gas can be used as a gas for plating squeezing, so that it is generated locally using city gas or natural gas which is easily available. Therefore, there is an advantage that the cost can be significantly reduced as compared with nitrogen gas transported and stored in a cylinder, and the handling can be remarkably simplified, such as eliminating the need for replacing cylinders.
If the content of 2 and H2 is set to 4% or more to provide reducibility, there is an advantage that a product having excellent gloss on the plating surface can be obtained as compared with nitrogen gas or the like. Further, according to the third and fourth aspects of the invention, the flowability of the hot-dip coating layer until the solidification point is reached is reduced, so that the dripping of the molten metal can be prevented. Since it is possible to cool the wire uniformly from the surroundings and to increase the pulling speed of the wire, there is an advantage that a thick plating layer can be formed while keeping the appearance smooth.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram showing one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a forced air cooling device used in the above.

FIG. 3 is a schematic system diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wire rod 2 Plating tank 3 Gas throttle part 4 Non-oxidizing gas source or heat generating gas generator 5 Water cooling device 6 Top roller 7 Sinker roller 8 Forced air cooling device 9 Inner cylinder 10 Pressurized air supply pipe 11 Pressure chamber 12 Ventilation cylinder 13 Rectification Board

Continuation of front page (72) Inventor Tomio Kizu 2-15-1, Kyomachi, Chuo-ku, Tokyo

Claims (4)

[Claims] 1. A wire rod plating apparatus provided with a gas throttle unit for supplying a non-oxidizing gas to a plating bath surface at a rising portion of a wire rod to prevent oxidation of the bath surface, wherein the non-oxidizing gas has a dew point of -40. A wire rod plating apparatus that uses a heat-generating atmosphere gas that has absorbed moisture up to a temperature of less than or equal to ° C. 2. The wire rod plating apparatus according to claim 1, wherein the carbon monoxide and hydrogen components of the heat-generating atmosphere gas are each at least 4% by volume. 3. A gas cooling portion for supplying a non-oxidizing gas to a plating bath surface at a rising portion of a wire to prevent oxidation of the bath surface, and water cooling for rapidly cooling the wire above the gas narrowing portion. In a wire rod plating apparatus provided with a device, a wire rod plating apparatus comprising a forced air cooling device for cooling a hot-dip layer of a wire rod to near a solidification point by an air flow parallel to the wire rod in an intermediate portion between the gas narrowing unit and the water cooling device. . 4. A forced air cooling device, wherein an inner cylinder through which a wire passes is provided at the center, and a ventilation passage through which a wire passes along a central axis at an upper end of a pressure chamber having a pressurized air supply port on a side wall. The wire rod plating apparatus according to claim 3, wherein an air flow parallel to the wire rod is formed in the ventilation cylinder by connecting the cylinders.