JPH06264205A - In-bath rolless hot dip metal coating device - Google Patents

Abstract

PURPOSE:To simplify the hot dip coating device and to produce a hot dip coated steel sheet with excellent productivity by providing the hot dip coating device with solid contact type wiping devices having a specific structure in place of gas wiping devices. CONSTITUTION:The steel sheet 8 which is to be plated and is emitted from a heating furnace 10 is passed through a plating cell 9 contg. a hot dip coating bath, such as molten Zn, and thereafter, the steel sheet is pulled up from the plating bath and the coating weight of the plating metal on the surfaces of the steel sheet 8 is adequately controlled by the solid contact type wiping devices 7. The solid contact type wiping devices 7 are constituted by disposing a pair of ceramic materials 12, 12, such as Si3N4, contg. heaters 11 opposite to each other. The one ceramic material 12 is fixed to a solid wall surface 13 and the other ceramic material 12 is formed as a moving type. The coating weight of the molten Zn on the surfaces of the steel sheet 8 traveling between both ceramic materials 12 and 12 is adjusted by adjusting the pressing force of this ceramic material. The need for a sink roll and snap roll in the plating bath is eliminated by a combination with a deflector roll 14 as an introducing device for the steel sheet 8 and the galvanized steel sheet is produced with good productivity by the simple device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-dip galvanizing apparatus used for hot-dip galvanizing such as hot-dip galvanizing.

[0002]

2. Description of the Related Art For example, specifications for thin steel sheets used for building materials, home electric appliances, and automobiles have become stricter year by year, and particularly, specifications for corrosion resistance have become extremely high. In order to achieve such a specification, a plated steel sheet is often used as the above-mentioned thin steel sheet.

The hottest galvanized steel sheet is a hot-dip galvanized steel sheet. Such a plated steel sheet is usually used after being further coated in the final product, and in addition to corrosion resistance, smoothness of the finished surface after coating and adhesion to the coated surface are also required. Properties are important.

FIG. 4 is an explanatory view showing a structural example of a conventional hot dip galvanizing apparatus for hot dip galvanizing (hereinafter, hot dip galvanizing will be described as an example). As shown in the figure, the material to be plated 1 is heated to a predetermined temperature by a heating furnace 2 and then obliquely introduced into a hot dip galvanizing bath 3 containing a hot dip galvanizing bath 3 ′ for hot dip galvanizing. But,
Sink rolls 4 and snap rolls 5 and 5 are arranged inside the hot dip galvanizing tank 3 in order to prevent sagging and pass stabilization at the time of sheet passing, and a gas wiping device is provided above the hot dip galvanizing tank 3. 6 is arranged to control to a predetermined basis weight. Reference numeral 14 in the figure is a deflector roll.

By the way, since dross, scale, etc. generated during hot dip galvanization adhere to the surface of each roll in the hot dip galvanizing bath 3, the surface of the material to be plated 1 that comes into contact with these rolls is indented. This may cause surface flaws, or in the worst case, cause non-plating. At present, the quality of each roll is dealt with by improving the material, and the quality is managed somehow.

When the hot dip galvanizing apparatus is continuously operated, the sink rolls 4 and the snap rolls 5 and 5 in the hot dip galvanizing bath are gradually worn mainly in the roll shaft portion and the bearing portion. Therefore, the vibration becomes remarkable.
Therefore, the path of the material to be plated 1 becomes unstable. In particular, since the snap rolls 5 and 5 are normally connected to the drive unit and driven, when the balance between the wear of the bearing unit and the vibration of the drive unit is lost, violent vibration occurs, and this vibration is applied to the plated material 1. In some cases, the accuracy of the gas wiping is deteriorated due to the propagation, and the control of the basis weight is even insufficient.

Thus, the sink roll 4 and the snap rolls 5 and 5 arranged in the hot dip galvanizing bath are
The line had to be stopped several times a month, and replacement and repair had to be performed during this stop. Therefore, the production capacity is inevitably reduced and maintenance management becomes complicated, which is one of the causes of an increase in the manufacturing cost of the hot-dip galvanized steel sheet, and improvement thereof has been conventionally desired.

[0008]

Thus, an object of the present invention is to develop a hot-dip galvanizing apparatus capable of improving both productivity and quality as compared with conventional ones. Specifically, It is an object of the present invention to provide a hot-dip galvanizing apparatus capable of eliminating the quality deterioration and the cost increase due to the roll immersed in the metal plating bath and the gas wiping apparatus.

[0009]

By the way, the inventors of the present invention have previously disclosed a solid contact type wiping device 7 having a sectional structure shown in FIG. This is a device that is installed as an alternative to the conventional gas wiping device and controls the basis weight.It is composed of a pair of ceramic materials (example: silicon nitride) 12 with a built-in heater 11 facing each other. 12 is fixed to the fixed wall surface 13 and the other is movable, so that the pressing pressure between the ceramic materials 12, 12 can be adjusted, and by adjusting the pressing force, the melt that runs between both ceramic materials 12, 12 is melted. The weight per unit area of the galvanized steel sheet 8 is adjusted. Further, the solid contact type wiping device 7 is not just a device for adjusting the basis weight, as described in Japanese Patent Application Laid-Open No. 5-9690, but has a path stabilizing and warp correcting function like a snap roll. It is equipped with.

As described above, it is easily conceivable that it is not necessary to install a snap roll by using the solid contact type wiping device proposed by JP-A-5-9690. However, it was completely unclear whether a sink roll need not be installed in addition to the snap roll.

Therefore, as a result of further intensive studies by the present inventors, the use of the solid contact type wiping device eliminates the need to install a sink roll in addition to the snap roll, which is a problem of the conventional hot dip galvanizing device. The present invention has been completed by finding that all of the above can be eliminated.

Here, the gist of the present invention is a molten metal plating apparatus having a molten metal plating tank for containing a molten metal plating bath, and further, a molten metal plating apparatus arranged on the inlet side of the molten metal plating tank. An in-bath rollless molten metal plating apparatus comprising a combination of a plating material introduction device and a solid contact type wiping device arranged above the exit side of the molten metal plating tank.

In the molten metal plating apparatus according to the present invention,
Above the molten metal plating bath, for example, a solid contact wiping device proposed by JP-A-5-9690 is provided,
This solid contact type wiping device has a function of a snap roll, and the sink roll and snap roll arranged in the conventional molten metal plating device are omitted.
Wiping is performed while maintaining the tension of the plated material to control the basis weight.

The contact between the material to be plated and the plating bath is
For example, it may be instantaneous within a depth of 500 mm of the plating bath, and the material to be plated forms a loop between the introducing device arranged on the inlet side of the molten metal plating bath and the solid contact wiping device. Therefore, the molten metal is introduced into the molten metal plating bath without performing the sink roll and the snap roll to perform the molten metal plating. Therefore, the molten metal plating apparatus according to the present invention does not use the sink roll and the snap roll.

[0015]

The operation of the present invention will be described in detail below. The in-bath rollless molten metal plating apparatus according to the present invention installs a solid contact type wiping apparatus as an alternative to the snap roll in the conventional molten metal plating apparatus to directly fix the material to be plated, and to remove the material to be plated at the time of wiping. We are trying to stabilize. Thus, according to the in-bath rollless molten metal plating apparatus of the present invention, it is not necessary to install a snap roll.

Further, according to the apparatus for roll-less molten metal plating in a bath according to the present invention, a device for introducing a material to be plated (for example, a deflector roll) arranged on the inlet side of the molten metal plating tank and the solid contact type wiping described above. The equipment is used to support the material to be plated at two points. At this time, by applying an appropriate compressive stress to the material to be plated, the material to be plated is curved and stably passes through the molten metal plating bath. Therefore, it becomes possible to carry out the molten metal plating by passing through the molten metal plating bath without installing a sink roll or a snap roll.

When a deflector roll is used as an introducing device in the bath rollless molten metal plating apparatus according to the present invention, it is desirable to use a pinch roll type for sandwiching the material to be plated from above and below. This is because the value of the compressive stress generated in the material to be plated can be adjusted easily and reliably, and the plateability of the material to be plated in the molten metal plating bath can be more easily stabilized.

From the viewpoint of preventing dross defects and surface oxidation, the strip line between the snout and the solid contact wiping device and the surface of the molten metal plating bath are sealed with an inert gas or reducing gas atmosphere. It is preferable to have a structure that enables it.

In the conventional molten metal plating tank, since the sink roll and the like are arranged, it is impossible to make the depth of the molten metal plating tank shallower than at least the arrangement depth of the sink roll and the snap roll. However, in the molten metal plating tank according to the present invention, since it is not necessary to dispose a sink roll or the like in the molten metal plating bath, it is possible to make the depth of the molten metal plating tank shallow and downsize the molten metal plating tank. it can.

As described above, according to the present invention, when the material to be plated is introduced into the molten metal plating bath to carry out the molten metal plating, rolls disposed in the molten metal plating bath such as sink rolls and snap rolls. The present invention relates to a hot-dip galvanizing apparatus that eliminates the need for a solid metal contact type wiping device in place of the gas wiping device, snap rolls and sink rolls used in conventional hot-dip galvanizing devices, to stabilize the path to the material being plated. The feature is that the function and the function of maintaining tension are retained.

According to the present invention, product defects associated with sink rolls, snap rolls, and gas wiping can be eliminated, and the replacement and repair time of the sink rolls and snap rolls, and the cost thereof, can be greatly reduced. Therefore, according to the hot-dip galvanizing apparatus according to the present invention, it is possible to manufacture a hot-dip galvanized steel sheet with higher quality and at low cost. Further, it becomes possible to downsize the molten metal plating tank. Further, the present invention will be described in detail with reference to examples, but this is an example of the present invention and the present invention is not limited thereto.

[0022]

EXAMPLE FIG. 1 is an explanatory view showing an example of the structure of an in-bath rollless hot dip galvanizing apparatus 9 according to the present invention. In the figure, on the inlet side of the hot dip galvanizing tank 9, there is a deflector roll 14 which is a device for introducing the steel plate 8 which is the material to be plated.
And the solid contact wiping devices 7 are arranged above the exit side of the hot dip galvanizing bath 9, respectively. Reference numeral 10 in the figure is a heating furnace.
As shown in FIG. 2, the solid contact type wiping device 7 is made of a ceramic (silicon nitride) material having a heater 11 incorporated therein in order to maintain the temperature of zinc attached to the steel plate 8.

The steel plate 8 is supported at two points by a deflector roll 14 and a solid contact type wiping device 7,
A compressive stress of about 20 to 40 kgf / mm ² is applied to the steel plate 8. The steel sheet passing speed is 120 and 100 m / min.
It was a standard.

Here, the pressing force of the solid contact type wiping device 7 is changed at eight levels of 0, 0.1, 0.3, 0.5, 0.8, 1.0, 1.5 and 2.0 kg / cm ² , whereby the basis weight of the material 8 to be plated is changed. The amount was controlled. The weight per unit area was evaluated by the amount attached on both sides. Fig. 3 shows the relationship between the pressing force and the double-sided areal weight.
Is shown in the graph.

As can be seen from FIG. 3, by changing the pressing force of the solid contact wiping device 7, the basis weight changes as a function of the pressing force. Therefore, the pressing force with which the desired basis weight is obtained may be set in consideration of the line speed.

As described above, according to the apparatus of the present invention, an extremely high quality hot-dip galvanized steel sheet could be manufactured. In addition, this device reduces noise by not using a conventional air wiping device, suppresses edge overcoat by improving the unit weight control accuracy, push-in defects due to dross adhering to snap rolls or sink rolls, and sink roll defects. , Reduction of chatter marks, etc., improvement of productivity by eliminating line stop for replacing sink roll etc., improvement of maintainability by eliminating repair work of sink roll etc., reduction of line down time required, and lack of sink roll etc. It has become possible to reduce the operating cost by using it, and further downsize the plating tank.

[0027]

As described in detail above, according to the present invention, the occurrence of product defects caused by sink rolls, snap rolls, and gas wiping can be eliminated, and productivity can be greatly improved by reducing the line down time. In order to
The maintenance cost can be reduced and the cost can be reduced. Therefore, according to the present invention, it is possible to provide a hot-dip galvanizing apparatus capable of improving both productivity and quality, and to manufacture a better product at a lower cost, as compared with the prior art.

Specifically, since the solid contact type wiping device is used directly without using a snap roll, the path of the material to be plated is stabilized. Since the pass is stabilized, zero spangle or alloying treatment, which is a post-treatment of plating, can be performed stably.

According to the conventional air wiping method, an overcoat is likely to occur at the edge, but since the solid contact type wiping device can uniformly press the plated material, the width direction of the plated material is It is possible to obtain a uniform basis weight.

In the conventional air wiping method, a large amount of pressurized air is used, which causes not only cost increase but also noise problem. However, in the solid contact type wiping device, the pressing pressure can be freely controlled and quiet. The basis weight control can be performed in this state.

Since the molten metal plating apparatus according to the present invention does not use a sink roll or the like, it is possible to avoid the occurrence of dross indentation flaws and the like, and since there is no surface oxidation due to air wiping, a product with extremely good surface properties is manufactured. can do.

Since it is not necessary to secure a space for installing a sink roll or the like, the plating tank can be downsized. It was possible to obtain the remarkable effect.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a molten metal plating apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a solid contact type wiping device used in the molten metal plating device according to the present invention.

FIG. 3 is a graph showing the relationship between the pressing force and the double-sided areal weight of the solid contact type wiping device used in the molten metal plating device according to the present invention.

FIG. 4 is an explanatory diagram showing the configuration of a conventional hot-dip metal plating apparatus.

[Explanation of symbols]

1: Material to be plated 2: Heating furnace 3: Hot dip galvanizing bath 3 ': Hot dip galvanizing bath 4: Sink roll 5: Snap roll 6: Gas wiping device 7: Solid contact type wiping device 8: Steel plate 9: In the present invention Such molten metal plating apparatus 10: Heating furnace 11: Heater 12: Ceramic material 13: Fixed wall surface 14: Deflector roll

Claims (1)

[Claims] 1. A molten metal plating apparatus having a molten metal plating bath containing a molten metal plating bath, further comprising:
A bath comprising a device for introducing a material to be plated arranged on the inlet side of the molten metal plating tank and a solid contact wiping device arranged on the outlet side of the molten metal plating tank in combination. Medium rollless molten metal plating equipment.