KR20100052553A - Apparatus for producing molten metal plated steel strip and process for producing molten metal plated steel strip - Google Patents

Abstract

This invention provides an apparatus for producing a molten metal plated steel strip in which a gas is blown through a gas wiping nozzle (3) against the surface of a steel strip (S) being pulled up continuously from a molten metal plating bath (8) to regulate the amount of plating deposited on the surface of the steel strip. The apparatus comprises molten metal drawing members (1, 1) having a length equal to or larger than the width of the steel strip and disposed opposite to the steel strip (S) on both sides of the steel strip (S) in its part present under the surface of a liquid in a molten metal tank (9), and a shielding material (2) provided between the molten metal drawing members (1, 1) disposed opposite to the steel strip (S) on an extension of the steel strip surface. According to this apparatus, even when the steel strip width is varied, the amount of excess molten metal, which has accompanied the steel plate being pulled up from the plating bath, is reduced over the whole width of the steel strip, whereby the occurrence of splash in the step of gas wiping can be reduced.

Description

Apparatus for manufacturing molten metal plated steel strip and manufacturing method of molten metal plated steel strip {APPARATUS FOR PRODUCING MOLTEN METAL PLATED STEEL STRIP AND PROCESS FOR PRODUCING MOLTEN METAL PLATED STEEL STRIP}

This invention relates to the molten metal plating steel strip manufacturing apparatus which can reduce a molten metal splash in a molten plating process, and the manufacturing method of the molten metal plating steel strip using the apparatus.

General continuous hot-dip plating apparatus and process are demonstrated using FIG. The steel strip S is immersed in the molten metal plating bath 8 in the molten metal bath 9, and after switching to the sink roll 7, after pulling up the steel strip S vertically upwards, A gas wiping nozzle (3) extending in a band width direction formed to face the steel strip S therebetween so that the molten metal adhered to the surface becomes a predetermined plating thickness uniformly in the width direction of the plate and the length direction of the plate. The gas wiping device which blows a pressurized gas from a steel strip, removes excess molten metal, and controls the adhesion amount (plating adhesion amount) of molten metal is formed.

In order to stabilize the strong running position in a gas wiping part, when the bath support roll 5 is arrange | positioned under the bath surface above the sink roll 7, normally, when alloying etc. are performed as needed. A bath-like support roll 4 is provided above the gas wiping nozzle 3.

The gas wiping nozzle 3 is usually longer than the width of the steel band in order to cope with various steel band widths and to cope with misalignment in the width direction when lifting the steel band, that is, the width end of the steel band S. Extends from the outside to the outside. In such a gas wiping device, a so-called splash is generated in which molten metal falling below the steel strip is scattered to the surroundings due to the disturbance of the jetted stream colliding with the steel strip S, resulting in deterioration of the surface quality of the steel strip.

In addition, in the continuous process, in order to increase the production amount, it is only necessary to increase the steel strip plate speed, but in the case of controlling the plating deposition amount by the gas wiping method in the continuous hot dip plating process, due to the viscosity of the molten metal, Since the initial deposition amount immediately after the steel strip passes through the increase in line speed, the wiping gas pressure must be set to a higher pressure in order to control the plating deposition amount within a certain range, so that the splash is greatly increased. Increase and it is impossible to maintain good surface quality.

In order to solve the said problem, the method of reducing the initial amount of adhesion immediately after passing a plating bath by reducing the excess molten metal accompanying a steel plate to some extent before reaching a wiping nozzle is disclosed.

In Japanese Laid-Open Patent Publication No. 2004-76082, after forming a molten metal reducing member that is opposed to a non-contact on both sides of a steel strip between a support roll 5 and a wiping nozzle 3 in a plating liquid to remove excess plating, In the apparatus for adjusting the plating thickness by ping, the shape of the molten metal reducing member is preferably a shape or a cylinder having an inlet portion in which the distance from the upper and lower surfaces of the molten metal reducing member becomes wider as the rectangle or the lower end thereof. As for the installation position of a member, the position which spreads up and down of the plating liquid surface is said to be most preferable. Moreover, it is said that it is desirable for the molten metal reducing member to surround a steel strip.

By the way, in this method, even if it is possible to reduce the excess molten metal in the center portion in the large width direction with the molten metal reducing member, the molten metal flows in from the outside toward the center portion in the large width direction at both ends in the large width direction. At both ends of the direction, the effect of reducing the molten metal is lowered. Therefore, in the width direction center part and both ends, the difference in the amount of excess molten metal becomes larger than the case where the said molten metal reducing member is not provided, and the effect which reduces a splash in a subsequent gas wiping process falls that okay. Moreover, in the shape which enclosed the steel strip disclosed by this method, since the width change of the steel strip to manufacture cannot be responded, the width size of the board which can express the reducing effect of molten metal is limited.

In view of the above problems, the present invention can reduce the occurrence of a splash in the gas wiping process by enabling the reduction of the excess molten metal accompanying the steel sheet drawn up from the plating bath over the entire width of the steel strip even if the steel strip width changes. Let it be a subject to provide the molten metal plating steel strip manufacturing facilities which can manufacture the molten metal plating steel strip excellent in the surface appearance stably.

Moreover, an object of this invention is to provide the manufacturing method of the steel strip which can reduce generation | occurrence | production of the splash in a gas wiping process, and can manufacture stably the molten metal plating steel strip which is excellent in surface appearance.

This invention is a molten metal plating steel strip manufacturing apparatus which (1) injects gas from a gas wiping nozzle to the surface of the steel strip continuously pulled up from a molten metal plating bath, and controls the plating adhesion amount of a steel strip surface, A molten metal On both sides of the steel strip under the liquid level of the bath, there is a molten metal reducing member having a length greater than or equal to the width of the steel strip disposed opposite to the steel strip, and a shielding body is disposed between the molten metal reducing members disposed opposite the steel strip on the steel strip extension. It is a molten metal plating steel strip manufacturing apparatus.

In addition, (2) the strip traveling direction length of the strip facing surface of a shielding body is 50% or more of the strip moving direction length of the strip facing surface of a molten metal reduction member (the strip traveling direction length of the strip facing surface of a molten metal reduction member is strong. When different from both sides of, the steel strip extending direction length of the steel sheet opposing surface of the molten metal reducing member is 50% or more of the steel strip traveling direction length of the steel sheet opposing surface), and the distance between the molten metal reducing member and the shielding body is 3 mm or less. It is a molten metal plating steel strip manufacturing apparatus as described in (1) characterized by the above-mentioned.

Moreover, it is also invention of the manufacturing method of the molten metal plating steel strip characterized by performing molten metal plating to a steel strip using the manufacturing apparatus of the molten metal plating steel strip as described in (3) (1) or (2).

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows one Embodiment of the molten metal plating steel strip manufacturing apparatus of this invention.
FIG.2 (a) and FIG.2 (b) are figures explaining the action | action of the molten metal reducing member and a shield of the molten metal plating steel strip manufacturing apparatus of this invention.
3 is a first diagram illustrating a combination example of a cross-sectional shape of a molten metal reducing member and a shielding body used in the molten metal plated steel strip manufacturing apparatus of the present invention.
4 (a) and 4 (b) are second diagrams illustrating a combination example of the cross-sectional shape of the molten metal reducing member and the cross-sectional shape of the shielding body provided in the molten metal plated steel strip manufacturing apparatus of the present invention.
FIG.5 (a) and FIG.5 (b) are 3rd figure explaining the example of a combination of the cross-sectional shape of the molten metal reduction member and the cross-sectional shape of a shield which are provided in the molten metal plating steel strip manufacturing apparatus of this invention.
FIG.6 (a) and FIG.6 (b) is a 4th figure explaining the example of a combination of the cross-sectional shape of the molten metal reduction member and the cross-sectional shape of a shield which are provided in the molten metal plating steel strip manufacturing apparatus of this invention.
7 is a cross-sectional view showing a general molten metal plated steel strip manufacturing apparatus.

Best Mode for Carrying Out the Invention

If a molten metal reducing member for removing excess molten metal is provided between the sink roll and the gas wiping nozzle, the molten metal removed by the gas wiping flows downward, thereby causing a gap between the steel strip and the molten metal reducing member. Form a liquid pool. Since the amount of excess molten metal cannot be reduced when the distance from this liquid pool to the gas wiping section is short, the present inventors have concluded that it is best to install the molten metal reducing member below the plating liquid surface.

However, even if only the molten metal reducing member is provided, the molten metal reducing effect at both ends of the steel strip is small. Therefore, in order to effectively reduce the amount of molten metal accompanying the steel strip from the plating bath, detailed flow analysis was performed using a water model apparatus that simulates the flow of molten metal around the molten metal reducing member. As a result, it was found that in order to reduce the amount of molten metal that is attached to the steel strip and lifted from the plating bath, it is effective to suppress the flow from the both ends of the steel strip toward the center of the steel strip.

The present inventors completed the invention based on the above findings.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described with reference to drawings. In the following drawings, the same code | symbol is attached | subjected to the part of the action same as the action of the part shown in the figure after description, and the description is abbreviate | omitted.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows one Embodiment of the molten metal plating steel strip manufacturing apparatus of this invention. In FIG. 1, 1 is a molten metal reduction member provided in the plating bath, and is provided in the position spaced apart from the steel strip surface on both sides with the steel strip S interposed above the support roll 5 in a bath. 2 is a shield, and is arrange | positioned adjacent to the steel strip S end part between molten metal reducing members 1 and 1 arrange | positioned facing the steel strip S on a steel surface extension. The "steel surface extended image" means the line shape parallel to the width direction of a steel strip. In addition, a "shielding body" is a member which shields a plating liquid, and suppresses the flow of the plating liquid toward the center part of a steel strip from both ends of a steel strip.

2 (a) and 2 (b) are diagrams for explaining the action of the molten metal reducing member and the shielding body of the apparatus of the present invention, and FIG. 2 (a) shows the molten metal reducing member in the case of having only the molten metal reducing member. FIG. 2 (b) is a top view showing the flow of molten metal at the end of the steel strip in the interposed region; FIG. 2 (b) shows the molten metal reducing member and the shielded body 2 in the region sandwiched between the molten metal reducing member. It is a top view which shows the flow of the molten metal in the steel strip edge part. Regardless of the shape of the molten metal reducing member 1, when only the molten metal reducing member 1 is disposed, a flow of molten metal 11 from the end of the steel strip toward the center of the steel strip occurs as shown in Fig. 2A. The greater the plating reduction effect by the molten metal reducing member 1, the larger the flow 11 of this molten metal tends to replenish it. Therefore, the reducing effect of the molten metal reducing member 1 is weakened or extinguished at both ends of the steel strip. As shown in Fig. 2 (b), when the shielding body 2 is disposed between the molten metal reducing members 1 and 1 arranged opposite to the steel strip on the steel surface extension, the flow of molten metal from the steel sheet end toward the steel center portion is shown. Since it is possible to block, the excess molten metal reduction effect by the molten metal reducing member 1 can be uniformly expressed over the entire width of the strip.

Even if the steel band width is changed, since the amount of excess molten metal accompanying the steel band by the molten metal reducing member and the shielding body is reduced over the whole steel band width, the plating thickness can be adjusted with the gas wiping nozzle, thereby greatly reducing the amount of splash generation. You can. According to the present invention, since the molten metal reduction effect can be expressed even if the sheet speed is greatly increased, the amount of splash can be greatly reduced. Thus, a molten metal plated steel strip without surface defects can be produced while maintaining high productivity. It becomes possible.

It is preferable that the steel strip side cross section of the shielding body 2 orthogonally crosses a steel strip surface like FIG.2 (b). The distance between the steel strip end portion and the steel strip side cross section of the shielding body 2 is preferably 5 mm or less, and the smaller the distance is, the more preferable. Furthermore, it is the most preferable condition that the steel strip edge part and the steel strip side end surface of the shielding body 2 contact in the state in which the pressing force with respect to the steel strip does not act.

The gap between the molten metal reducing member 1 and the shield 2 is preferably 3 mm or less, and the smaller the gap, the better.

From the viewpoint of preventing the flow toward the steel strip center of the molten metal between the molten metal reducing members 1 and 1, the steel sheet traveling direction length (vertical direction length) of the steel plate facing surface of the shielding body 2 is at least molten metal reducing. It is preferable that it is 50% or more of the length of the steel plate advancing direction of the member 1, and it is most preferable that it is a length equivalent to the molten metal reducing member 1.

When the distance between the steel strip opposing face and the steel strip of the molten metal reducing member 1 changes in the steel strip traveling direction, the gap between the molten metal reducing member 1 and the shielding body 2 in the steel strip traveling direction should be kept as constant as possible. desirable. For example, when the cross-sectional shape of the molten metal reducing member 1 is circular as shown in FIG. 3, the surface facing the molten metal reducing member 1 of the shielding body 2 is the molten metal reducing member 1. It is preferable to comprise a concave circular arc surface which has a radius of curvature slightly larger than the radius of curvature of the circular arc.

The cross-sectional shape of the molten metal reducing member is not limited to the shape of FIG. 3. As described below, various shapes can be adopted. For example, as shown to Fig.4 (a), when a cross-sectional shape is a triangle and the surface which faces the steel strip S, and the upper surface which concerns a bath surface are parallel to the steel strip S and the bath surface, respectively, a molten metal decreases. The reduction performance of the member 1 can be further improved. When the cross-sectional shape of the molten metal reduction member 1 is made into such a shape, even if the flow (accompaniment flow) 11 accompanying the progress of the steel strip S generate | occur | produces, since fluid tends to flow in a direction with small resistance, it melt | dissolves The flow 13 branches off at the lower end of the metal reducing member 1 and functions to hinder the growth of the accompanying flow 11. In addition, since the flow 13 faces the direction away from the steel strip S, it faces the flow 12 toward the steel strip S above the molten metal reducing member 1, and thus the velocity of the flow 12 It also has the effect of weakening. Since the molten metal reducing member 1 performs the flow control as mentioned above, it becomes possible to largely suppress the accompanying flow in the vicinity of the steel strip S lifted from the plating bath, and the excess molten metal plating accompanying the steel strip S is carried out. Can reduce the amount of As a result, the wiping gas pressure can be lowered, and the amount of generation of the molten metal splash can be reduced to produce a plated steel strip having good surface quality. In this case, the cross-sectional shape of the shielding body 2 may be made rectangular as shown in FIG.4 (b).

The cross-sectional shape of the molten metal reduction member 1 of FIG. 5 (a) is a circular arc shape in which both the cross-sectional curve of the upper surface and the cross-sectional curve of the lower surface are convex in the convex pull-up part side of a molten metal plating bath, and the radius of curvature of an upper surface arc The lower surface is formed to be smaller than the radius of curvature of the arc. In addition, the thickness of the molten metal reducing member 1 is reduced toward the anti-barrel side end portion and the half bath surface side end portion. The shape of this molten metal reducing member 1 is the shape which most remarkably shows the effect which branches the accommodating flow 11 into the flow 13, and the effect which forms the counterflow with respect to the flow 12. As shown in FIG.

In this case, the surface opposing the molten metal reducing member 1 of the shielding body 2 is a circular arc of the surface opposing the shielding body 2 of the molten metal reducing member 1 as shown in FIG. 5 (b). It is preferable to comprise a concave circular arc surface having a radius of curvature slightly larger than the radius of curvature, and to keep the distance between the molten metal reducing member 1 and the shield 2 as constant as possible.

The molten metal reducing members 1a and 1b shown to Fig.6 (a) are the roll covering parts formed so that the bath surface side of the outer peripheral surface of the support roll 5 in a bath may be covered, and the steel plate oppositely arrange | positioned so as to oppose a steel strip. Part. The bath support rolls 5 are arrange | positioned so that both sides of a steel strip may contact a steel strip, and their vertical direction positions may mutually differ. Therefore, the strip traveling direction lengths of the strip opposing portions of the molten metal reducing members 1a and 1b disposed on both sides of the strip S are different. The strip opposing parts of the molten metal reducing members 1a and 1b may be parallel to or inclined with respect to the strip surface.

In this molten metal reducing member 1a, 1b, the flow 14 accompanying the bath supporting roll 5 generate | occur | produces between the bath support roll 5 and molten metal reducing member 1a, 1b. When the flow 14 occurs, even if the accompanying flow 15 accompanying the propagation of the steel strip S occurs, the direction of travel of the steel strip S between the steel strip S and the molten metal reducing members 1a and 1b and Forced flow 16 in the opposite direction occurs, greatly suppressing the accompanying flow 15. Thereby, the amount of excess molten metal accompanying the steel strip S pulled up from a plating bath can be reduced.

The molten metal reducing member may be provided with only the steel opposing portions of the molten metal reducing members 1a and 1b shown in Fig. 6A. In this case, the length of the strip moving direction of the strip opposing part of the molten metal reducing members 1a and 1b arrange | positioned on both sides of a strip may be the same.

6 (a) and the said case, what is necessary is just to make the cross-sectional shape of the shielding body 2 into a rectangle as shown in FIG. 6 (b). In this case, the strip moving direction length of the strip facing surface of a shielding body is 50% or more of the strip moving direction length of the strip facing surface of a molten metal reduction member (The strip traveling direction length of the strip facing surface of a molten metal reduction member is both sides of a strip. When different from, it is preferable that the steel strip running direction length of the steel sheet opposing face of the molten metal reducing member is 50% or more of the steel strip running direction length of the steel sheet opposing surface), and It is more preferable that it is the same length as the advancing direction length (the same length as the advancing direction length of the small band opposing surface when the steel strip advancing length of the steel strip opposing surface of a molten metal reducing member differs on both sides of a steel strip).

It is necessary to determine the size and shape of the molten metal reducing member appropriately in consideration of the equipment to be applied and the sheet speed of the steel strip.

It is preferable to make the steel strip traveling direction height of the shielding body 2 equal to the molten metal plating reducing member 1, and at the time of installation, the vertical direction positions of the upper and lower ends of the molten metal reducing member 1 and the shielding body 2 are carried out. It is desirable to match. When the steel plate traveling direction length of the shielding body 2 is shorter than the steel plate traveling direction length of the molten metal reducing member 1, the shielding body 2 is installed in the side near a bath surface, ie, the upper part of the shielding body 2 is a molten metal reducing member. (1) It is preferable to set it as substantially the same position as an upper end. As for the length of the strong width direction of the shielding body 2, 100 mm or more is preferable. Although an upper limit is not limited, When this length becomes large, installation will become excessive, About 500 mm or less is preferable.

Example

The molten metal plating steel strip manufacturing apparatus shown in FIG. 1 was installed in the continuous hot dip galvanizing line, and the manufacturing experiment of the molten zinc plating steel strip was performed. The vertical direction offset amount of the bath support rolls arrange | positioned at the both sides of the steel strip S is 200 mm, and the distance between the bath surface and the bath support roll upper end on the side near a bath surface is 80 mm. The support roll diameter in the bath is Φ 400 mm.

The strip width direction length of the molten metal reducing member 1 is set to 2000 mm corresponding to the gas wiping nozzle, and the distance between the upper end of the molten metal reducing member and the bath surface is 5 mm and the distance between the strip is 3 mm (Comparative Example 5 and Example). 4) except for 4). The shielding body 2 was set to 200 mm in the wide width direction length, and it was connected directly to the place which extended the frame from the position control apparatus by the servomotor provided in the base side, and was able to move along the large width.

The hot-dip galvanized steel strip manufacturing conditions are 0.8 mm of slit gap of a gas wiping nozzle, 7 mm of gas wiping nozzle-strength distances, nozzle height 400 mm from a hot dip zinc bath, and hot dip zinc bath temperature of 460 degreeC. The size of was 0.8 mm thick x 1.2 m wide, and the coating weight was 45 g / m 2 on one side. The distance between the shield 2 and the steel strip end was controlled to approximately 3 mm.

Table 1 shows the results of the investigation of the amount of splashes used as other manufacturing conditions and product quality indexes. The specific dimensional shape of the molten metal reducing member and shielding body used in each comparative example and each Example is demonstrated below. The splash generation amount is a ratio of the strip length determined as having a splash defect in the inspection process with respect to the strip length which passed each manufacturing condition, and contains the splash defect of hardness which does not become a problem practically.

Comparative example 1 (conventional example) is a case where there is neither a molten metal reducing member nor a shielding body. The splash rate was 1.40%.

Comparative Example 2 uses only a molten metal reducing member having a square cross-section having a steel strip traveling direction length and a horizontal direction length of 50 mm, respectively, and Example 1 further shows that the steel strip traveling direction length is 50 mm. And the shielding plate of rectangular cross section which is 4 mm of horizontal lengths was further installed (the distance of a molten metal reduction member and a shielding plate is 1 mm). In Comparative Example 2, the splash occurrence rate was approximately 25% lower than in Comparative Example 1. In Example 1, the splash generation rate was almost half that of Comparative Example 1, and the splash rate was approximately 31% reduced in Comparative Example 2.

In Comparative Example 3, only the molten metal reducing member whose both the strip moving direction length and the horizontal direction length were 50 mm and the cross-sectional shape was triangular was arranged as shown in Fig. 4A. Example 2 additionally provided the shield of the rectangular cross section of the same dimension shape as Example 1 about Comparative Example 3 as shown in FIG.4 (b) (the distance of a molten metal reduction member and a shield plate is 1 mm). to be). In Comparative Example 3, the splash occurrence rate was approximately 70% lower than in Comparative Example 1. In Example 2, the splash generation rate was 80% lower than that of Comparative Example 1, and the splash rate was approximately 32% lower than that of Comparative Example 3.

In Comparative Example 4, only the molten metal reduction member having both the steel strip traveling direction length and the horizontal direction length of 50 mm and the cross-sectional shape having an arc shape (upper curvature radius of 60 mmR and lower curvature radius of 100 mmR) is shown in Fig. 5 (a). It arrange | positioned as shown to). The distance from the steel strip at the bottom of the molten metal reducing member was 3 mm.

In Comparative Example 4, Example 3 further has a cross-sectional shape shown in FIG. 5 (b), that is, a steel plate traveling direction length of 50 mm, and the molten metal reducing member facing the molten metal reducing member of the shielding body. A shield formed by a concave circular arc surface having a radius of curvature slightly larger than the radius of curvature of an arc of a surface opposing the shield of the shield, and manufactured so that the distance from the molten metal reducing member is 1 mm is shown in FIG. Additional installation as indicated.

In Comparative Example 4, the splash occurrence rate was approximately 84% lower than in Comparative Example 1. In Example 3, the splash generation rate was reduced by approximately 90% in Comparative Example 1, and the splash generation rate was reduced by about 30% in Comparative Example 4.

The comparative example 5 is the arc-shaped roll coating part which covers the bath surface side of the outer peripheral surface of the bath support roll 5 formed so that the distance of the bath support roll 5 and the molten metal reduction members 1a and 1b may be set to 30 mm. And molten metal reducing members 1a and 1b having plate-shaped steel sheet opposing portions formed such that the distance between the steel strip and the molten metal reducing members 1a and 1b is a constant 20 mm and the distance between the upper end and the bath surface is 30 mm. Bay was arrange | positioned as shown to FIG. 6 (a).

In Comparative Example 5, Example 4 further provided a shielding body in which the steel strip travel direction length was 100 mm and the horizontal direction length was 36 mm, as shown in FIG. 6 (b). The distance between the shield and the molten metal reducing member is 2 mm. The ratio of the molten metal reducing member 1b to the strip traveling direction length of the strip opposing portion of the strip traveling direction length of the shielding body is approximately 90%.

In Comparative Example 5, the splash occurrence rate was approximately 85% lower than in Comparative Example 1. In Example 4, about 94% of the splash incidence was reduced in Comparative Example 1, and about 33% of the splash incidence was reduced in Comparative Example 5.

As described above, according to the present invention, even if the steel band width is changed, after reducing the amount of excess molten metal incident to the steel band by the molten metal reducing member and the shielding body formed under the plating bath surface, the gas wiping nozzle is used. Since the plating thickness can be adjusted, the amount of splash generation can be greatly reduced. Moreover, even if the plate | board speed is largely raised, since the generation amount of splash can be reduced significantly, it becomes possible to manufacture the molten metal plating steel strip without surface defects, maintaining high productivity.

Industrial availability

The apparatus of this invention reduces generation | occurrence | production of a splash, and can be used as a manufacturing apparatus of the molten metal plating steel strip excellent in the surface appearance. Since the generation | occurrence | production of a splash can be suppressed also at the time of a high speed gutter, the apparatus of this invention can be used as an apparatus which manufactures the molten metal plating steel strip which is excellent in surface appearance, maintaining high productivity. Moreover, the manufacturing method of the steel strip of this invention reduces generation | occurrence | production of a splash, and can be used as a manufacturing method of the molten metal plating steel strip which is excellent in surface appearance.

Claims (3)

A molten metal plating strip manufacturing apparatus which sprays gas from a gas wiping nozzle to a surface of a steel strip continuously drawn up from a molten metal plating bath, and controls the plating adhesion amount of the steel strip surface, on both sides of the steel strip under the liquid surface of the molten metal bath. A molten metal reducing member having a molten metal reducing member having a width greater than or equal to the width of the steel strip and disposed between the molten metal reducing members disposed opposite to the steel strip on the steel surface extension. Device. The method of claim 1,
The strip traveling direction length of the strip facing surface of a shielding body is 50% or more of the strip moving direction length of the strip facing surface of a molten metal reduction member (The strip traveling direction length of the strip facing surface of a molten metal reduction member may differ on both sides of a strip. At a time of 50% or more of the length of the steel sheet facing direction of the steel sheet facing surface of the molten metal reducing member), and the distance between the molten metal reducing member and the shielding body is 3 mm or less. Metal plating steel strip manufacturing device. A molten metal plating is performed on a steel strip using the manufacturing apparatus of the molten metal plating steel strip of Claim 1 or 2, The manufacturing method of the molten metal plating steel strip characterized by the above-mentioned.

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