JPS6056419B2 - Metal band stabilization device for plating in continuous contact plating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous hot-dip plating apparatus in which a permanent magnet applies tension to a metal strip continuously pulled out of a hot-dip plating bath and shelving the metal strip in a non-contact state. This invention relates to a band shelf fastening device.

Conventionally, as a device for applying thin plating such as aluminum to a metal strip, such as a steel strip, the steel strip is continuously inserted into a hot-dip plating bath using a conveying means such as a zinc roll, and the steel strip is pulled out from the hot-dip plating bath. It is well known to use a wiping device to wipe away excess hot-dip plating from the surface. Recently, the plating thickness is controlled in a non-contact manner by injecting gas such as high-temperature gas onto the metal strip immediately after it has been pulled out of the hot-dip plating bath.

A so-called gas wiping device has been developed, and plating accuracy has been significantly improved. By the way, in such continuous hot-dip plating equipment, the conditions for improving the accuracy of plating thickness are as follows:
It is desirable to uniformly inject gas from a gas wiping device onto both surfaces of the metal strip immediately after it has been pulled out of the molten metal J-kissing bath, thereby achieving uniform wiping. As equipment becomes faster and larger, the vibration of the metal band in the gas wiping device increases, making it difficult to obtain a uniform plating thickness, which poses a problem in terms of accuracy.

For this reason, the inventors conducted various studies to resolve the problems associated with conventional continuous hot-dip plating equipment, and found that a magnetic type using permanent magnets was used to reduce the vibration of the metal strip immediately after it was pulled out of the hot-dip plating bath. The idea was to prevent this in a non-contact state by using a vibration prevention device. That is, magnetic means using permanent magnets are installed facing the edge of the metal strip to be plated from the outside in the width direction, and by applying tension in the width direction of the metal strip, the metal can be plated in a non-contact state. The purpose is to prevent deflection of the strip in the width direction and thickness direction, and to improve plating accuracy without worrying about equipment wear and tear or damage to the plating film.

By the way, typical permanent magnets include ferrite magnets, cast magnets, and rare earth cobalt magnets.

In particular, rare earth cobalt magnets have an extremely high coercive force, and by using them, a large tension can be obtained with a small magnet, making it possible to effectively operate the device by utilizing the limited space near the gas wiping nozzle. It is possible to arrange
It can be made effective in increasing the space utilization rate. However, this rare earth cobalt magnet is expensive because it mainly contains rare earth elements such as Sm (samarium) and CO (cobalt). This has become an obstacle to practical application.

The present invention has been made in view of these circumstances, and provides a metal band steadying device for plating in continuous hot-dip plating equipment, which promotes miniaturization by efficiently using permanent magnets, thereby reducing costs. ``The purpose is to provide equipment.

The present invention is characterized by a hot-dip plating bath, a conveying means for continuously passing the metal strip to be plated through the hot-dip plating bath, and a conveying means for removing the metal strip from the hot-dip plating bath. Provided at the drawer position of the plated metal strip.
a wiping device for wiping away excess hot-dip plating metal adhering to the surface of the metal strip to be plated; a wiping device located near the wiping device and facing the edge portion of the metal strip to be plated from the outside in the width direction; A steady magnetic means for applying tension in the width direction to the metal strip to be plated in a non-contact state by a permanent magnet, and a distance between the steady magnetic means and the metal strip to be plated is automatically adjusted. an adjusting device, a rare earth metal cobalt is used as a permanent magnet of the magnetic means, and permanent magnet width B=maximum thickness of metal strip to be plated.
(Tmax) x 5 to 20 Permanent magnet thickness H = Maximum thickness of metal strip to be plated
(Tmau) ×
5 to 20 Permanent magnet gap e=set gap G×2 to 5.

That is, by adopting such a configuration, permanent magnets can be used efficiently and the size can be made as small as possible.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. 1
2 is a hot-dip plating bath, and 2 is a conveying means for continuously inserting a metal strip to be plated, for example, a steel strip 3, into the hot-dip plating bath. It consists of a drawer roll etc.

Reference numeral 5 designates a gas wiping device, in which a pair of gas wiping nozzles 5A are arranged on both sides of the steel strip 3 drawn out vertically above the hot-dip plating bath.

By uniformly injecting compressed gas onto both surfaces of the steel strip 3 from each gas wiping nozzle 5A, excess molten plated metal is wiped off and the amount of deposited metal is controlled. Reference numeral 6 denotes a magnetic means for stabilizing the steel strip, which is located near the gas wiping device 5, for example, above it, and is installed opposite to both edge portions 3A of the steel strip 3 from the outside in the width direction, and is driven by a permanent magnet. It is designed to apply tension in the width direction to the steel strip 3 in a non-contact state.

Each magnetic means 6 includes a water jacket type cylindrical case 7 facing the edge portion 3A of the steel strip 3 with a predetermined gap G therebetween;
It has a permanent magnet 8 attached to the edge side of the cylindrical case 7 and extending over a predetermined length range LO.

The cylindrical case 7 is made of a non-magnetic material, and is configured to be supplied with cooling water through a water supply hole 7A and to drain the cooling water through a drainage hole 7B. A permanent magnet 8 is supported by one piece of a columnar support block 9 provided approximately at the center of the cylindrical case.
The cylindrical case is supported by a motor 10 and a screw 11 so as to be movable toward and away from the edge portion 3A of the steel strip 3. The permanent magnet 8 has a plurality of substantially rectangular parallelepiped magnet bodies each having a predetermined length L and a predetermined width B arranged in a line at intervals with non-magnetic intermediate flocs 12 interposed between them. There are things. Note that 13 is a lid for sealing the cylindrical case 7, and 14 is a sealing member for preventing leakage of cooling water. By cooling the permanent magnet 8 by circulating the cooling water in the cylindrical case in this manner, deterioration of the magnetism of the permanent magnet 8 due to high heat is prevented. By the way, it is known that the attractive force that can act on the steel strip 3, which is a non-attractive member, is saturated in proportion to the thickness t of the steel strip 3, and it is useless to strengthen only the magnetic force. ing.

On the other hand, the vibration damping force required to prevent vibrations is related to the mass of the steel strip 3, and in the case of a flat plate like a steel strip, it is related to the thickness of the plate.
As the plate thickness increases, the required damping force also increases. For example, when the copper strip 3 is made of ordinary carbon steel, as shown in FIG. 5, when the gap G between the permanent magnet 8 and the steel strip 3 is constant, the attractive force F increases as the plate thickness t increases. It has the following characteristics.

In other words, there is a favorable phenomenon in which as the required force increases, the acting magnetic force also increases almost commensurately with this increase, so by utilizing this characteristic, it is possible to create an effective magnetic force using the minimum amount of magnets required. It is designed to have a damping effect. That is, there is a limit to the suction force depending on the thickness t of the steel strip 3, and this relationship is shown in FIG.

This figure shows that when the steel strip material is ordinary carbon steel with LO,=500Tr$t, the saturation suction force improves as the plate thickness t increases. In addition, Fig. 7, Fig. 8, and Fig. 9 are
These are experimental results showing the relationship between the width B, height H, magnet spacing' of the permanent magnets, the gap G between the model permanent magnet 8 and the model steel strip 3, and the attractive force F using the model shown in the figure.

FIG. 7 shows that even if the magnet height H is increased, the magnetic force is saturated after several tens of millimeters.

Therefore, it can be seen that a range of H/t=5 to 20 is sufficient. Furthermore, FIG. 8 shows that even if the magnet width B is increased, the magnetic force is saturated after several tens of millimeters. Therefore B
It is determined that sufficient tension is generated within the range of /t=5 to 20. As for the inter-magnet gap e, as shown in FIG. 9, if e/G is small, energy is wasted by attraction between the magnets and the attraction force F of the steel strip decreases. On the other hand, e/G
It was found that if the value is large, the magnet length L becomes insufficient with respect to LO, so that F also decreases in this case. That is, since the attractive force shows a maximum value near e/G=2 to 5, if the dimensions are set within this range, the permanent magnet can be used efficiently. With such dimensions and arrangement, the amount of permanent magnets used is reduced, the cylindrical case 7 is also made smaller, storage space can be used effectively, and it can be easily installed even in narrow spaces. become able to.

At the same time, the need for expensive rare earth cobalt magnets is reduced, making it economically viable.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the entire continuous hot-dip plating apparatus according to the present invention, FIG. 2 is a front view showing the entire continuous hot-dip plating apparatus according to the present invention, and FIG. 3 is a magnetic case of the steel strip steadying device according to the present invention. 4 is a longitudinal sectional view of the magnetic case of the steel strip steady rest device according to the present invention, FIG. 5 is a characteristic diagram showing the relationship between plate thickness and suction force, and FIG. 6 is a model equipment for measuring suction force. Figure 7 is a characteristic diagram showing the relationship between magnet height and attractive force, Figure 8 is a characteristic diagram showing the relationship between magnet width and attractive force,
FIG. 9 is a characteristic diagram showing the relationship between the gap between the magnets and the attractive force. DESCRIPTION OF SYMBOLS 1...Hot-dip plating bath, 2...Transportation means, 3...Metal/strip, 3A...Edge portion, 5...Wiping device, 6...Magnetic means, 10, 11... Adjustment device, 8.
··permanent magnet.

Claims (1)

[Scope of Claims] 1. A hot-dip plating bath, a conveying means for continuously inserting the metal strip to be plated into the hot-dip plating bath, and a conveying means provided at a position where the metal strip to be plated is pulled out from the hot-dip plating bath. a wiping device for wiping away excess hot-dip plating metal adhering to the surface of the metal strip to be plated; and a wiping device located near the wiping device and facing the edge of the metal strip to be plated from the outside in the width direction. , a magnetic means for steadying that applies tension in the width direction to the metal strip to be plated in a non-contact state using a permanent magnet, and automatically adjusting an interval between the magnetic means for steadying and opposing the metal strip to be plated. A rare earth metal cobalt is used as a permanent magnet of the magnetic means, and permanent magnet width B = maximum thickness of metal strip to be plated (tmax) x 5 to 20, permanent magnet thickness H = metal strip to be plated. Maximum thickness (tmax)
×5 to 20 A metal band steadying device in a continuous hot-dip plating apparatus, characterized in that the gap between permanent magnets l=set gap G×2 to 5.