JPH07173596A - Edge overcoat preventive device for hot dip metal coating - Google Patents

Abstract

PURPOSE:To efficiently prevent edge overcoating at all times by providing edge plates equipped opposite to the transverse end faces of a hot dip coated steel sheet moving between wiping nozzles with orthogonal band-shaped plates. CONSTITUTION:Wiping gases are sprayed to the hot clip coated steel sheet 4 moving between the wiping nozzles 3 and 3 facing each other to control the coating surface density. The edge plates 1 are spatially installed opposite to the transverse end faces of the steel sheet 4. Further, the band-shaped plates 2 having the width not exceeding the spacing distance of the wiping nozzles 3, 3 are disposed nearly orthogonally with the ends of the edge plates 1 on the steel sheet 4 side. The surfaces of the band-shaped plates 2 facing the ends of the plated steel sheet 4 are partly formed as arcs or slopes. The distances between the edge plates and the plated steel sheets are preferably set at 10 to 20mm in gas collision positions and at <=4mm in the upper parts thereof. As a result, gas turbulence and further, the edge overcoating based on splashes are effectively prevented even if there is warpage in the plated steel sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing edge overcoat of molten metal plating when controlling the basis weight by spraying a wiping gas onto a molten metal plated steel sheet.

In particular, the present invention relates to a device for preventing edge overcoat of hot-dip galvanizing which can always expect a certain effect regardless of any widthwise warp of the steel sheet between the wiping nozzles. The present invention also relates to an edge overcoat prevention device that prevents the molten metal from adhering to the end of the plated steel sheet due to splash.

[0003]

2. Description of the Related Art As is well known, the basis weight of hot-dip galvanizing is performed by blowing a wiping gas from a wiping nozzle on the front and back surfaces of a plated steel sheet toward the plated steel sheet. However, the so-called edge overcoat phenomenon in which the molten metal excessively adheres to the edges of the steel sheet is unavoidable.

The cause of this is that the wiping gases ejected from the opposing wiping nozzles collide with each other at both ends of the steel sheet, causing a turbulent flow of the wiping gas. It is considered that the amount of water vapor decreases, the wiping gas flows inward from the end of the coated steel sheet, and the end of the coated steel sheet is supercooled.

Further, the wiping gas ejected from the wiping nozzle causes a so-called splash phenomenon in which the molten metal at both ends of the plated steel sheet is blown off as described above, clogging of the wiping nozzle and other unit for adjusting the basis weight, and molten metal on the plated steel sheet. Had been attached.

At present, in order to solve such a problem,
So-called edge plates are provided at both ends of the steel plate to expand the virtual plate width by installing the plate in an extension region of the steel plate in the width direction.

[0007] For example, an edge plate (baffle plate) such as an edge overcoat preventive device disclosed in Japanese Patent Laid-Open No. 91535/1975, which is capable of fine movement adjustment in the steel plate width direction or the steel plate advancing direction, is installed to form a plated steel plate. Even if the forward / backward or left / right shake occurs due to a change in the traveling speed, the distance between the hot-dip galvanized steel sheet and the edge plate (baffle plate) is kept to 1 mm or less and the structure is automatically maintained.

Further, like the edge overcoat preventing device disclosed in Japanese Patent Laid-Open No. 63-105955, spacers are arranged on the front and back surfaces of the edge plate to prevent suction (tilt) of the edge plate. There is also a structural device.

FIG. 1 is a schematic explanatory view of a conventional representative edge plate, in which the flow direction of the wiping gas in the width direction of the steel plate end portion when the hot-dip galvanized steel plate has a warp in the width direction is schematically shown. It shows with.

The conventional edge plate 1 shown in FIG. 1 is arranged in parallel with the wiping nozzle 3, and its end portion is opposed to the end portions of the plated steel sheet 4 running between the wiping nozzles with a certain space. There is. When the galvanized steel plate 4 warps at this time, the wiping gas collides at the steel plate end portion due to the gap between the steel plate end portion and the edge plate end portion, causing gas turbulence and causing edge overcoating. Occurrence was unavoidable. In the figure, the arrow indicates the flow of gas from the wiping nozzle 3.

Further, FIG. 2 shows a splash of molten metal by the wiping gas in the longitudinal direction of the end portion of the steel plate 4 when the conventional edge plate 1 is used, that is, a conceptual diagram of the scattering state. In the conventional edge plate 1 shown, the edge plate 1 and the steel plate 4 at the gas collision position 7
Since the distance A between and is close to 1 mm or less, the molten metal 9 scattered by the wiping gas adheres to the edge plate 1 and grows into the deposit 9. The deposit 9 sometimes drops from the edge plate and adheres to the end of the plated steel sheet.

[0012]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide an edge overcoat preventing device which can always obtain a constant effect even if the hot-dip galvanized steel sheet has any warp in the width direction. is there.

Still another object of the present invention is to provide an edge overcoat preventing device which prevents the molten metal from adhering to the end of the plated steel sheet due to splash.

[0014]

DISCLOSURE OF THE INVENTION The present invention is based on the finding that an edge overcoat can be effectively prevented by disposing a strip-shaped plate at the tip of the edge plate so that the edge plate is T-shaped. It is based.

Here, the gist of the present invention is to provide an edge plate spaced apart from the widthwise end face of the molten metal-plated steel sheet that moves between the opposing wiping nozzles, and the molten metal-plated steel sheet of the edge plate. An edge overcoat preventing device for molten metal plating, comprising a strip-shaped plate having a width that does not exceed the distance between the wiping nozzles and disposed substantially orthogonal to the end portion on the side.

Further, according to the present invention, the end face shape of the edge plate on the side of the plated steel plate is an arc or an inclined surface, and the distance between the edge plate and the steel plate at the gas collision position is 10 mm.
It is based on the finding that a thickness of about 20 mm can effectively prevent the molten metal from adhering to the edges of the plated steel sheet due to splash. The mechanism has not been fully clarified yet, but it is thought that the splash gives a kind of escape angle (region) of the molten metal.

Here, from another aspect, the present invention is an edge overcoat preventing device provided with edge plates which are spaced apart from each other so as to face the widthwise end faces of the hot-dip galvanized steel sheet moving between the opposing wiping nozzles. And the shape of the end portion of the edge plate on the side of the molten metal-plated steel sheet is an arc or an inclined surface, and between the edge plate and the molten metal-plated steel sheet at the gas collision position where the wiping gas collides with the edge plate. An edge overcoat preventing device for molten metal plating, characterized in that the distance is 10 to 20 mm, and the minimum distance between the edge plate and the molten metal plated steel sheet in the upper part of the steel plate longitudinal direction from the gas collision position is 4 mm or less. is there.

According to another modification of the present invention, the surface of the strip-shaped plate facing the end of the hot-dip galvanized steel sheet is at least partially formed as an arc or an inclined surface, so that the edge overcoat can be more effectively performed. Can be prevented. In this case, an arc or an inclined surface may be formed below the gas collision position so that the distance from the end surface becomes larger as it goes downward, and the upper end surface may be a vertical surface parallel to the end surface of the plated steel sheet. .

Furthermore, from another aspect, the present invention provides the above-mentioned edge plate with a distance between the edge plate and the molten metal-plated steel sheet at 10 to 20 mm at the gas collision position where the wiping gas collides with the edge plate. This is an edge overcoating prevention method for controlling the amount of hot-dip galvanized metal deposits while keeping the minimum distance between the edge plate and the hot-dip galvanized steel plate at the upper part in the longitudinal direction of the steel plate from the collision position to 4 mm or less.

[0020]

Next, the present invention will be described more specifically with reference to the accompanying drawings. FIG. 3 is a schematic explanatory view of an edge overcoat prevention device according to the present invention. In the drawing, a wiping gas flow direction in a width direction of a steel plate end portion when an edge plate 1 provided with a strip plate 2 is used. Are shown in abbreviated form.
The edge overcoat preventing device is provided so as to face both end surfaces of the plated steel sheet, but hereinafter, for convenience of description, only one side surface of the steel sheet will be described.

In the edge overcoat preventive apparatus according to the present invention shown in FIG. 3, the edge plates 1 are installed on both sides of the plated steel sheet 4 running between the wiping nozzles 3 arranged in parallel. , A strip-shaped plate 2 which is attached in a T-shape at a position substantially orthogonal to the edge plate and whose surface faces the end of the plated steel plate 4.
Set up.

According to this structure, even if the plated steel sheet 4 is warped during traveling, the gas on the edge plate side does not always collide with the gas on the steel sheet side due to the existence of the strip 2, so that a turbulent flow of gas occurs. It does not occur and the edge overcoat can always be prevented.

Next, FIG. 4 is a front view of the edge overcoat preventing device according to the present invention, and FIG. 5 is a schematic perspective view of the edge plate 1 to which the strip-shaped body 2 constituting the edge overcoat preventing device according to the present invention is attached. It is a figure.

As shown in FIG. 4, according to the present invention, the strip-shaped plate 2 forming a part of the edge plate 1 facing the end surface of the plated steel plate 4 is abutted via a supporting device 5 composed of a follower roller. It may be installed separately. The separation distance at this time is made as small as possible, but usually 4 mm or less is sufficient. In the figure, reference numeral 6 indicates a plating bath.

FIG. 5 is a schematic perspective view of the edge overcoat preventing device according to the present invention. The belt 2 is attached to one end of the edge plate 1 so as to be orthogonal to the edge plate 1 so as to have a T shape. Has been. Edge plate 1
It is fixed so that it becomes vertical. The strip plate 2 has a width W, and the width W is a width that does not exceed the distance between the wiping nozzles. This is because it is arranged between the two wiping nozzles 3 and as close to the steel sheet end as possible.

In addition, although not particularly described, an appropriate mechanism may be provided in place of the supporting device 5 so that the strip-shaped body fixed to the edge plate follows the end of the steel plate.

Next, FIG. 6 (a) shows that according to the present invention, the end surface of the edge plate 10 is at least partially arcuate or inclined, that is, tapered, and the edge plate 10 and the steel plate 4 are in a gas collision position 7. Distance A between 10 to 20 mm
FIG. 4 is a conceptual diagram of the molten metal scattering state by the wiping gas in the longitudinal direction of the steel plate end portion when the above edge plate is used.

FIG. 6 (b) is a schematic side view showing only the edge plate 10 used at that time. The illustrated example shows a case where the edge plate end surface 11 forms an inclined surface 12 downward from the gas collision position. Of course, this may be an arcuate surface. The distance from the end surface of the steel plate increases as it goes downward. The shape of the end surface 11 of the edge plate 10 above the gas collision position is not particularly limited, but is usually a vertical surface parallel to the steel plate end surface.

In any case, the hot dip galvanized steel plate and the edge plate 10 above the gas collision position.
By setting the separation distance B between and to as small as possible, for example, 4 mm or less, the conventional wiping gas rectifying effect of the edge plate 1 and the steel plate end portion does not change, and the edge overcoat preventing effect is not impaired.

As shown in FIGS. 6 (a) and 6 (b), in the edge plate 10 according to the present invention, the distance A between the edge plate 10 and the steel plate 4 at the gas collision position 7 is 10 to 20 mm. Therefore, the molten metal 8 scattered by the wiping gas is unlikely to adhere to the edge plate. That is, it is possible to prevent the molten metal deposit 9 of FIG. 2 from adhering to the end of the plated steel sheet.

Next, FIGS. 7 (a) and 7 (b) are a schematic front view of an edge overcoat preventing device according to the present invention and a schematic perspective view of a modified example of the edge plate 20 used therein.

That is, in the apparatus according to the present invention, as shown in FIG.
An end plate 11 below the gas collision position 7 is an arc or taper surface, that is, an edge plate 10 having an inclined surface, and both end surfaces are supported by the supporting device 5 abutting on the steel plate 4 as in the case of FIG. Are installed facing each other. In this case as well, the distance A
By arranging the edge plate 20 so that the distance is 10 to 20 mm and the distance B is 4 mm or less, it is possible to effectively prevent the edge overcoat.

FIG. 7B shows the edge plate 20 shown in FIG.
It is a perspective view showing a modified example when the strip-shaped plate 22 is provided in,
In the illustrated example, the strip plate 22 has a tapered surface as a whole, but the strip plate 22 may have a tapered surface only below the position corresponding to the gas collision position. Providing such a band-shaped plate 22 effectively functions even when the steel plate is warped. Even in these cases, the distance A is limited to 10 to 20 mm and the distance B is limited to 4 mm or less. Particularly, when the strip-shaped plate 22 is an overall convex surface or a taper surface in which the upper part faces the lower part, the distance B is set so that the apex thereof is located above the gas collision position, and the distance between the apex and the end surface of the steel plate is set. The distance becomes the distance B.

As a further modification, it is possible to provide the strip plate 22 only above the gas collision position.
It takes a larger splash escape area.

Next, the function and effect of the present invention will be described more specifically with reference to Examples.

[0036]

【Example】

(Example 1) In this example, when the steel plate is warped in the width direction, hot metal plating of metal Zn is performed under the same conditions using a conventional edge plate and the edge plate of the present invention shown in FIG. It was The distance between the steel plate end surface and the strip plate surface is 4
held in mm. The plating conditions were as follows.

Plate thickness: 0.6 mm Plate width: 920 mm Adhesion amount (both sides): 250 g / m ² Line speed: 110 m / min Wiping pressure: 0.2 kg / cm ^{2 The} results are shown in Fig. 8 center and steel plate. As shown by the ratio of the amount of adhesion to the edge, the ratio of the amount of adhesion is smaller when the edge plate of the present invention is used than when the conventional one is used, and the edge overcoat is more effectively prevented. You can see that It can be seen that the edge overcoat was significantly reduced to 1.0 according to the present invention, which was 1.4 in the conventional example. If this ratio is within 1.1, it is practically acceptable.

In the figure, white circles show the case where the steel plate has no warp, and black circles show the index of the edge overcoat when the steel plate having a warp of about 10 mm at the steel plate end is used. .

Example 2 In this example, the conventional edge plate and the edge plate of the present invention shown in FIG. 6 were used to carry out hot metal plating under the same conditions. The plating conditions were as follows.

Plate thickness: 0.6 mm Plate width: 920 mm Adhesion amount (both sides): 250 g / m ² Line speed: 110 m / min Wiping pressure: 0.2 kg / cm ² Between edge plate and steel plate above gas collision position Distance: 4
The mm results are shown in Table 1 as the time until the molten metal deposit adheres to the steel plate, and the ratio of the amount of adhesion between the steel plate central portion and the steel plate end portion. The distance between the edge plate and the steel plate at the gas collision position was changed by adjusting the height of the edge plate with respect to the gas collision position and changing the position of the tapered surface.

From Table 1, when the distance between the edge plate and the steel plate at the gas collision position is less than 10 mm, the molten metal deposited on the edge plate is likely to adhere to the steel plate. On the other hand, when the distance between the edge plate and the steel sheet is larger than 20 mm, the ratio of the adhered amount between the end portion and the central portion of the steel sheet is 1.3, and the edge overcoat is likely to occur.

That is, when the distance between the edge plate and the steel sheet at the gas collision position is 10 to 20 mm, the edge plate according to the present invention prevents the molten metal deposit from adhering to the steel sheet and prevents the edge overcoat. You can see that

The ratio of the adhered amount between the end portion and the central portion of the steel plate is 1.1
Within was accepted.

The conventional edge plate having a vertical surface shown in FIG. 2 is used, and the distance from the steel plate end surface is 5 mm to 10 mm.
However, when the thickness exceeds 5 mm, the above-mentioned adhesion amount ratio exceeds 1.2.

[0045]

[Table 1]

[0046]

As described above, according to the present invention, even when the hot-dip galvanized steel sheet has any warp in the width direction, the strip-shaped plate attached to the edge plate edge portion prevents Since no collision of wiping gas occurs and no turbulent flow of gas occurs, edge overcoating can always be prevented.

Further, according to the present invention, an edge plate having an end face shape of an arc or a taper and a distance between the edge plate at the gas collision position and the steel plate being 10 to 20 mm is used to form a plated steel plate with molten metal deposits. To the edge and a certain effect of preventing edge overcoat is obtained.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a conventional edge overcoat prevention device.

FIG. 2 is a conceptual diagram of a molten metal scattering state by a wiping gas in a longitudinal direction of a steel plate end portion when a conventional edge plate is used.

FIG. 3 is a schematic explanatory view of an edge overcoat prevention device according to the present invention.

FIG. 4 is a front view of an edge overcoat preventing device according to the present invention.

FIG. 5 is a perspective view of an edge plate used in the edge overcoat preventing device according to the present invention.

FIG. 6 (a) shows the distance between the edge plate and the steel plate at the gas collision position in an arc or taper shape according to the present invention.
FIG. 6B is a conceptual view of the state of the molten metal scattered by the wiping gas in the longitudinal direction of the steel plate end portion when the edge plate is used as 10 to 20 mm, and FIG. 6B is a schematic side view of the edge plate.

FIG. 7 (a) is a schematic front view of an edge overcoat preventing device according to the present invention, and FIG. 7 (b) is a schematic perspective view of an edge plate provided with a strip plate.

FIG. 8 is a graph showing a ratio of adhesion amounts between a central portion of a steel sheet and edges of the steel sheet according to Example 1.

[Explanation of symbols]

 1: Edge plate 2: Strip plate 3: Wiping nozzle 4: Plated steel plate 5: Support device 6: Plating bath 7: Gas collision position 10: Edge plate 11: End face 12: Inclined surface (arc surface) 20: Edge plate 22: Strip

Claims (3)

[Claims] 1. An edge plate, which is installed so as to be opposed to a widthwise end surface of a molten metal-plated steel sheet that moves between opposed wiping nozzles, and is disposed substantially orthogonal to an end portion of the edge plate on the molten metal-plated steel sheet side. An edge overcoat preventing device for molten metal plating, comprising a strip-shaped plate having a width that does not exceed the distance between the wiping nozzles. 2. The apparatus according to claim 1, wherein the surface of the strip-shaped plate facing the end of the hot-dip galvanized steel sheet is at least partially arcuate or inclined. 3. An edge overcoat prevention device comprising edge plates which are spaced apart from each other so as to face widthwise end faces of a hot-dip galvanized steel sheet moving between opposed wiping nozzles, and the hot-dip galvanized steel sheet of the edge plate is provided. The shape of the end on the side is at least a part arc or inclined surface,
And the distance between the edge plate and the molten metal-plated steel sheet at the gas collision position where the wiping gas collides with the edge plate is 10 to 20 mm, and the edge plate and the molten metal-plated steel sheet at the upper portion in the steel plate longitudinal direction from the gas collision position. An edge overcoat prevention device for molten metal plating, characterized in that the minimum distance is 4 mm or less.