JPS61177362A - Hot dipping method - Google Patents

Abstract

PURPOSE:To control freely the adhered quantity of metal dipped on a surface of a material to be treated by passing the material to be treated through a molten metallic bath for the dipping to dip it and thereafter passing it between a couples of DC electromagnetic coils having the spit-shaped magnetic pole teeth just after floating up it from the dipping metallic bath. CONSTITUTION:The dipping metal is stuck on a surface of a material 5 to be treated which is drawn out of a molten metallic bath 6 for the dipping and passed between the spit-shaped magnetic pole teeth 3, 4. At this time DC is conducted through the exciting coils 2 wound on the yokes 1, 1 of the magnetic pole teeth 3, 4. The magnetic flux enters the magnetic pole 4 through the material 5 from the magnetic pole 3 and the eddy current is conducted through the material 5 and the molten metal 6 stuck on the surface thereof by means of the elevation of the material 5 and the electromagnetic force direction downward is acted on the molten metal and it is returned to the dipping bath 6. The adhered quantity of the dipping metal 6 can be controlled by the magnitude of current conducted through the exciting coils 2. The material 5 is prevented from bringing into contact with the magnetic poles 3, 4 by the vibration by providing the nozzles 8 between the magnetic poles 3, 4 and injecting an inert gas and the damage of the dipped surface is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hot-dip plating method in which a material to be treated is passed through a molten metal bath, and particularly to a method for controlling the film thickness.

[Conventional technology]

Conventionally, in the hot-dip plating method, the plating thickness is determined by injecting high-pressure gas onto the treated material immediately after passing through a molten metal bath.
The gas waste method, in which excess plated metal is allowed to flow down into a lower bath, is widely used.

[Problem that the invention seeks to solve]

In the above method, since the thickness is controlled by jetting gas, it is difficult to obtain a uniform plating thickness even when the line speed changes or the plate thickness changes.

In addition, when the line speed is increased, the horizontal deflection of the plate increases as the plate moves, and as it comes into contact with the nozzle, the nozzle gap must be widened, and there is a limit to controlling the plating thickness with gas injection alone. There was a problem.

Next, as another conventional example, Japanese Patent Publication No. 58-23464 describes hot-dip plating in which, after removing excess plating by electromagnetic force, a heating element is injected from a nozzle onto the plating surface to control the plating thickness. The law has been disclosed. However, the electromagnetic force in this hot-dip plating method is often generated by a moving magnetic field generated by an AC linear motor. Therefore, the linear motor has a core wall that constitutes a linear motor armature by inserting a large number of coils into a laminated iron core having a large number of slots, and has a problem in that the structure is complicated.

In addition, since the above nozzle is located above the area where electromagnetic force acts, and its purpose is to suck up the molten plating, increasing the line speed will cause the plate to be processed to move. As a result, the problems of lateral vibration of the plate increasing and contact with the iron core and nozzle remained unsolved, leading to problems in terms of reliability.

This invention was made in order to solve the problems of the conventional ones as described above. Hot-dip plating in which a pair of DC electromagnetic coils are placed facing each other, and the material to be treated immediately after passing through the bath is passed through the gap between them, and an electromagnetic force is applied to the molten metal adhering to the surface, and the thickness of the plating film is controlled by controlling this electromagnetic force. The purpose is to obtain the law.

Another object of the present invention, in addition to the above object, is to provide a hot-dip plating method in which the material to be processed does not come into contact with the magnetic pole even when the line speed is increased.

[Means for solving problems]

In the hot-dip plating method according to the present invention, the material to be treated immediately after floating from the molten metal bath is passed through a gap between a pair of opposing DC electromagnetic coils having skewer-shaped magnetic pole teeth, thereby coating the surface of the material to be treated. The amount of deposited molten metal is controlled by applying electromagnetic force to the deposited molten metal and adjusting the excitation.

In addition, the hot-dip plating method according to another aspect of the present invention sprays an inert gas onto the material to be treated from a plurality of nozzles provided in the gaps between the skewer-shaped magnetic pole teeth, thereby preventing the material from coming into contact with the magnetic poles. This was prevented.

[Effect]

In this invention, a pair of DC electromagnetic coils having skewer-shaped magnetic pole teeth are placed opposite each other, the material to be treated is passed through the gap, and an electromagnetic force is applied to the molten metal adhering to the material to be treated. The purpose is to control the plating film thickness by controlling the
The structure of the plating device becomes simple.

In another invention of the present invention, even if the line speed is increased and the lateral runout of the material to be processed increases, the inert gas injected from the nozzle provided in the gap between the skewer-shaped magnetic pole teeth The material to be treated does not come into contact with the magnetic pole.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) is the yoke, (2) is this yoke (1
), (3) is the magnetic pole tooth on one side forming a skewer shape, and (4) is the corresponding magnetic pole tooth on the other side. (1), (2), (3), (4)
As shown in the figure, two electromagnetic coils (one pair) are provided, one on each side. In addition, the magnetic pole (3),
(4) may be a steel ingot. FIG. 2 is a top view of the magnetic pole surface, and FIGS. 3 and 4 are side views thereof.

Now, when direct current is applied to the excitation coil (2), the magnetic pole (3) is magnetized to, for example, the N pole, and the magnetic pole (4) is magnetized to the S pole. )to go into. At this time, when the material to be treated (5) moves upward, an eddy current flows through the material to be treated (5) and the molten metal (6) attached to its surface, exerting an electromagnetic force that returns it downward. This causes the molten metal to be returned to the bathtub below. The above electromagnetic force is the excitation coil (2
) by controlling the current flowing through the

Next, since there is a gap between the magnetic pole (3) and the magnetic pole (4), connect the external pipe (7) to the pipe (7).
A plurality of molten metal nozzles (8) are provided here, and an inert gas that does not harm the molten metal is introduced from the nozzles (8) and is injected onto both sides of the material to be treated (5). (5
) even if the speed increases and the transverse vibration increases, the magnetic pole (3), (
4) can be prevented from coming into contact with the plated surface, and the plated surface will not be damaged.

〔Effect of the invention〕

As described above, according to the present invention, a pair of DC electromagnetic coils having skewer-shaped magnetic pole teeth are opposed to each other, a material to be treated is passed through the gap, and an electromagnetic force is applied to the molten metal attached to the material to be treated. Since the electromagnetic force is controlled to control the plating film thickness, the structure of the device is simplified.

According to another aspect of the present invention, inert gas is blown onto the material to be treated from a plurality of nozzles provided in the gaps between the skewer-shaped magnetic pole teeth. Since the material to be treated is prevented from coming into contact with the magnetic pole,
Highly reliable hot-dip plating can be obtained without damaging the plating surface.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a plan view showing the magnetic pole surface of an embodiment of the invention, Fig. 6 is a sectional view taken along the line 1-1 in Fig. 2, and Fig. The figure is a sectional view taken along the line IV-IT in FIG. 2. In the figure, (1a)...electromagnetic coil, (1)...yoke, (2)...excitation coil, (3) magnetic pole tooth, (4)...
- Magnetic pole teeth, (5)...-material to be treated, (6)...molten metal, (7)...pipe, (8)...nozzle. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) When plating the workpiece by passing it through a molten metal bath, the workpiece immediately after floating from the bath is passed through a gap between opposing electromagnetic coils with skewer-shaped magnetic pole teeth. , a hot-dip plating method characterized by applying electromagnetic force to molten metal adhering to the surface of a material to be treated and controlling the amount of molten metal adhering by adjusting excitation. (2) When plating the workpiece by passing it through a molten metal bath, the workpiece immediately after floating from the bath is passed through a gap between opposing electromagnetic coils with skewer-shaped magnetic pole teeth. , an electromagnetic force is applied to the molten metal adhering to the surface of the material to be treated, and by adjusting the excitation, the amount of molten metal adhering is controlled, and an inert gas is ejected from multiple nozzles installed between the skewer-shaped magnetic pole teeth. A hot-dip plating method characterized by spraying on a material to be treated to prevent the material from coming into contact with a magnetic pole and damaging the surface due to the vibration of the material and the suction force acting on the plate surface.