JP4998696B2 - Manufacturing apparatus for molten metal plated steel strip and method for manufacturing molten metal plated steel strip - Google Patents

Description

  The present invention relates to a molten metal plated steel that can stably produce a molten metal plated steel strip having excellent surface appearance by reducing the occurrence of splash at a normal plate feeding speed and at a high speed plate passing in a hot-dip plating process. The present invention relates to a strip manufacturing facility and a method for manufacturing a molten metal-plated steel strip.

  In a continuous hot dipping process or the like, as shown in FIG. 3, the steel strip 3 is generally immersed in a plating bath 8 filled with molten metal and the direction is changed by a sink roll 7. After the step of pulling upward, the steel strip width provided facing this steel strip 3 so that the molten metal adhering to the steel strip surface has a predetermined plating thickness uniformly in the plate width direction and the plate longitudinal direction. There is provided a gas wiping device for jetting pressurized gas from the gas wiping nozzle 4 extending in the direction onto the steel strip, squeezing excess molten metal, and controlling the adhesion amount (plating adhesion amount) of the molten metal. Yes.

  In order to stabilize the traveling position of the steel strip in the gas wiping section, a support roll 6 in the plating bath is usually disposed below the bath surface above the sink roll, and when alloying is performed, gas is used as necessary. A support roll 5 is installed above the wiping nozzle 4.

  The gas wiping nozzle 4 is usually longer than the width of the steel strip, that is, extending beyond the width end of the steel strip 3 in order to cope with various widths of the steel strip and at the same time shift in the width direction when the steel strip is pulled up. ing. In such a gas wiping apparatus, a so-called splash is generated in which molten metal falling below the steel strip is scattered by disturbance of the jet that has collided with the steel strip 3, and the surface quality of the steel strip is degraded.

  Moreover, in order to increase the production amount in the continuous process, the steel plate passing speed may be increased. However, in the case of controlling the coating amount by the gas wiping method in the continuous hot dipping process, due to the viscosity of the molten metal, Since the initial adhesion amount (lifting amount) immediately after passing through the plating bath of the steel strip increases as the steel strip passage speed increases, the wiping gas pressure must be increased to control the plating coverage within a certain range. It must be set, which greatly increases splash and makes it impossible to maintain good surface quality.

  In order to solve the above-described problem, a method of reducing a certain amount of excess molten metal before reaching the gas wiping portion from the molten metal plating tank is disclosed as follows.

  In Patent Document 1, a molten metal squeeze member is provided between the support roll in the plating bath and the gas wiping nozzle in a non-contact manner on both surfaces of the steel strip, and after removing excess plating, the plating thickness is obtained by gas wiping. In addition, the shape of the molten metal squeezing member is preferably a rectangular shape or a cylindrical body having an introduction portion whose distance from the front and back surfaces of the steel strip becomes wider toward the lower end, and the installation position of the molten metal squeezing member is A molten metal plating apparatus is disclosed in which the position across the upper and lower surfaces of the plating bath is most desirable.

In Patent Document 2, a blade scraping device that is inclined with respect to the steel strip is provided on both surfaces of the steel strip on the surface of the plating bath, and after removing excess plating, the plating thickness is adjusted by gas wiping. A molten metal plating apparatus characterized in that a portion closest to the steel strip of the blade has a roundness of 30 mm or less in diameter is disclosed.
JP 2004-76082 A JP 2005-15837 A

  However, in the method disclosed in Patent Document 1, when the molten metal drawing member extends above the plating bath surface or above and below the plating bath surface, the molten metal finally removed by gas wiping flows down, A liquid puddle is formed in the gap between the steel strip and the molten metal throttle member, and the distance from the height of the liquid pool to the gas wiping part is short, resulting in a small throttle effect. There was a problem that the fixed and solidified metal adheres to the steel strip and causes surface defects.

  On the other hand, even when the molten metal squeezing member is arranged in the plating tank, the flow path is formed at the introduction portion as shown in FIG. Since it gradually narrows, the flow 13 concentrates on the flow 11 associated with the progress of the steel strip 3, and the flow velocity of the molten metal passing between the steel strip 3 and the molten metal throttle member increases. The amount of molten metal that eventually attracts the flow 12 above the member and eventually lifts from the bath surface increases, and the plating squeezing effect is reduced. It was easy to entrain a solid material (hereinafter referred to as dross), and this also caused surface defects.

  Further, in the method disclosed in Patent Document 2, even if the blade is tilted to round the steel strip tip, a liquid pool is formed at the upper end as in Patent Document 1, so that the gas wiping section As a result, the squeezing effect is small due to the short distance, and the molten metal stays in the area surrounded by the steel strip and the lower end of the blade. .

  In view of the above-mentioned problems, the present invention is a molten metal that can stably produce a molten metal-plated steel strip that reduces the occurrence of splash and is excellent in surface appearance at both normal plate speed and high-speed plate passing. It is an object to provide a plating steel strip manufacturing facility.

  In addition, the present invention provides a method for producing a steel strip that can stably produce a molten metal-plated steel strip that reduces the occurrence of splash and has an excellent surface appearance, both at normal plate speed and during high-speed plate feeding. The task is to do.

  When installing the molten metal throttle member for removing excess molten metal between the sink roll and the gas wiping nozzle, the present inventors have a short distance between the liquid pool position and the gas wiping position as described above. As a result, there arises a problem that the surplus plating amount cannot be reduced, so that it is concluded that it is best to install the molten metal drawing member below the plating bath surface. However, if the cross-sectional shape of the molten metal squeezing member is the same as the prior art, the squeezing effect is small.

  Therefore, in order to effectively reduce the amount of molten metal plating accompanying the steel strip coming out of the plating tank, detailed flow analysis is performed using a water model device that simulates the flow of molten metal around the molten metal throttle member. went. As a result, the amount of molten metal lifted along with the steel strip is influenced by the so-called accompanying flow (flow 11 in FIG. 4) flowing in the steel strip traveling direction in the vicinity of the steel strip surface and this accompanying flow. It was clarified that it was generated near the plating bath surface due to the flow and the viscosity of the molten metal, and was a flow perpendicular to the steel strip surface and directed toward the steel strip (flow 12 in FIG. 4). The smaller the former accompanying flow, the better the smaller the latter flow, and it was found that it would be more effective if the latter flow could be canceled and moved away from the steel strip.

  Based on the above knowledge, the present inventors have intensively studied the shape of the molten metal drawing member, and as a result, completed the invention having the following characteristics.

(1) A molten metal plating steel strip manufacturing apparatus that controls the amount of plating on the surface of a steel strip by blowing gas from a gas wiping nozzle onto the surface of the steel strip that is continuously pulled up from the molten metal plating bath. On both sides of the steel strip below the liquid level of the molten metal tank, there is a molten metal drawing member having a length equal to or greater than the width of the steel strip arranged facing the steel strip, and the surface of the molten metal drawing member facing the steel strip The surface of the molten metal squeeze member is the same between the upper part and the lower part of the molten metal squeeze member, or the upper part of the molten metal squeeze member is larger than the lower part and is not opposed to the steel strip of the molten metal squeeze member ( An apparatus for producing a molten metal-plated steel strip, characterized in that a distance between the steel strip and the top of the molten metal squeezing member) is larger than a lower portion of the molten metal squeezing member.
(2) In the apparatus for manufacturing a molten metal plated steel strip according to (1), the upper end of the surface of the molten metal drawing member facing the steel strip is arranged so that the distance from the steel strip increases as it goes upward. An apparatus for producing a molten metal-plated steel strip, characterized by being formed into a curved surface.

(3) In the apparatus for manufacturing a molten metal-plated steel strip according to (1) or (2), a cross-sectional shape of a vertical cross section perpendicular to the steel strip surface of the molten metal drawing member is a triangle. Manufacturing equipment for molten metal-plated steel strip.
(4) In the apparatus for manufacturing a molten metal-plated steel strip according to (1) or (2), a cross-sectional shape of a vertical cross section perpendicular to the steel strip surface of the molten metal drawing member is an inverted L-shape. Manufacturing equipment for molten metal plated steel strip.

(5) In the apparatus for manufacturing a molten metal-plated steel strip according to (1) or (2), the cross-sectional shape of the vertical cross section perpendicular to the steel strip surface of the molten metal drawing member is the cross-section of the top surface of the molten metal drawing member Both the curve and the cross-sectional curve of the bottom surface of the molten metal squeezing member are convex on the steel strip lifting side of the molten metal plating bath, and at least the thickness of the cross-bath end portion side of the cross-section is the anti-bath surface side An apparatus for manufacturing a molten metal-plated steel strip, wherein the apparatus is formed so as to decrease toward an end portion.
(6) In the apparatus for manufacturing a molten metal-plated steel strip according to (5), the cross-sectional curve of the top surface of the molten metal drawn member is an arc-shaped curved portion at least in a portion facing the steel strip lifting portion of the molten metal plating bath. The cross section curve of the lower surface of the molten metal squeezing member has an arcuate curved portion at the back of at least a portion of the molten metal plating bath facing the steel strip lifting portion, and the curvature radius of the arcuate curved portion of the upper surface is the lower surface An apparatus for producing a hot-dip metal-plated steel strip, characterized by being smaller than the radius of curvature of the arcuate curved portion.

  (7) In the apparatus for manufacturing a molten metal-plated steel strip according to any one of (1) to (6), the molten metal having a depth within 50 mm from the liquid surface of the plating bath is further flowed away from the steel strip. An apparatus for producing a molten metal-plated steel strip, characterized by comprising a fluidizing device.

  (8) A method for producing a molten metal-plated steel strip, comprising performing molten metal plating using the apparatus for producing a molten metal-plated steel strip according to any one of (1) to (7).

  According to the present invention, since the plating thickness can be adjusted by gas wiping after reducing excess plating metal by the molten metal drawing member in the plating bath, the amount of splash generated is greatly reduced even if the sheet feeding speed is increased. In addition, it is possible to stably manufacture a plated steel strip having no surface defects while maintaining high productivity. In the apparatus of the invention which concerns on Claims 2-7, the effect which reduces the generation amount of a splash is more excellent.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view showing an embodiment of the apparatus for producing a molten metal plated steel strip of the present invention. In FIG. 1, 1 is a molten metal throttle member, and 2 is a flow device. The molten metal squeezing member 1 is installed below the bath surface at a position away from the steel strip surface by a predetermined distance with the steel strip 3 interposed therebetween.

  2 (a) to 2 (d) are longitudinal sectional views (vertical sectional views perpendicular to the steel strip surface) illustrating an embodiment of the molten metal drawing member 1 installed in the molten metal plated steel strip manufacturing apparatus of FIG. The example of the cross-sectional shape of the molten metal squeezing member 1 and the flow of the molten metal around the molten metal squeezing member 1 will be described.

  The cross-sectional shape of the molten metal squeezing member 1 in (a) is a triangle, and the surface facing the steel strip 3 and the top surface facing the bath surface are parallel to the steel strip 3 and the bath surface, respectively. If the cross-sectional shape of the molten metal squeezing member 1 is such a shape, even if a flow (associated flow) 11 accompanying the progress of the steel strip 3 is generated, the fluid is likely to flow in a direction with low resistance. The flow 13 branches off at the lower end of the throttle member 1 and functions to prevent the growth of the accompanying flow 11. Furthermore, since the flow 13 is directed away from the steel strip 3, the flow 13 faces the flow 12 toward the steel strip 3 above the molten metal squeezing member 1, and has an effect of reducing the speed of the flow 12. Since the molten metal squeezing member 1 performs the flow control as described above, it is possible to significantly suppress the accompanying flow in the vicinity of the steel strip 3 lifted from the plating bath, and excessive molten metal plating associated with the steel strip 3 is prevented. The amount can be reduced. As a result, the wiping gas pressure can be reduced, the amount of splashing can be reduced, and a plated steel strip with good surface quality can be produced.

  The cross-sectional shape of the molten metal squeezing member 1 in (b) is an inverted L shape formed by bending a flat plate having a predetermined thickness, a surface facing the steel strip 3, a surface facing the steel strip, an upper surface facing the bath surface, The lower surface on the side opposite to the bath surface is parallel to the steel strip 3 and the bath surface, respectively. Even if it is such a shape, the effect of suppressing the accompanying flow 11 and the flow 12 works similarly to the shape of (a), and the amount of excess molten metal plating accompanying the steel strip 3 can be reduced.

The molten metal squeezing member 1 in (c) has an arc shape so that the distance from the steel strip 3 increases as the upper end shape of the surface facing the steel strip 3 of the molten metal squeezing member 1 in (a) increases upward. It is a thing.
The radius of curvature R of the arc is preferably 1 mm or more and less than the shorter one of the vertical length and the horizontal length of the molten metal squeezing member 1. With such a shape, the accompanying flow 11 spreads toward the anti-steel strip side at the upper end portion of the molten metal squeezing member 1, so that a counter flow with respect to the flow 12 is formed, so that excess molten metal plating associated with the steel strip is formed. The effect of reducing the amount can be further improved. For the molten metal squeezing member 1 of (b), the same effect can be obtained even if the upper end portion of the surface facing the steel strip 3 is formed in an arc shape.

  As for the cross-sectional shape of the molten metal squeezing member 1 in (d), the cross-sectional curve on the upper surface and the cross-sectional curve on the lower surface are both convex arcs on the steel strip lifting part side of the molten metal plating bath, and the curvature of the arc on the upper surface. The radius is formed to be smaller than the radius of curvature of the arc on the lower surface. Moreover, the thickness of the molten metal squeezing member 1 decreases toward the end portion on the anti-steel strip side and the end portion on the anti-bath surface. The shape of the molten metal squeezing member 1 is the shape that most significantly demonstrates the effect of branching the accompanying flow 11 into the flow 13 and the effect of forming the counterflow to the flow 12 as described above.

  The cross-sectional shape of the molten metal squeezing member 1 does not have to be formed in a circular arc as long as the cross-sectional curve of the upper surface and the cross-sectional curve of the lower surface are both convex toward the steel strip lifting portion side of the molten metal plating bath. A part may be linear (for example, the end side is straight), or may be a curve other than an arc. The end of the molten metal squeezing member 1 preferably has a shape whose thickness decreases toward the end at least on the side of the anti-bath surface, as shown in FIG. More preferably, both decrease in thickness toward the end.

  The curvature radius on the upper surface side is preferably 1 mm or more and not more than the shorter one of the vertical length and the horizontal length of the molten metal squeezing member 1. The curvature radius on the lower surface side only needs to be larger than the curvature radius on the upper surface side. In terms of flow control, the end thickness of the molten metal squeezing member 1 is preferably 3 mm or less, and preferably 0.5 mm or more from the viewpoint of strength. It is preferable to perform R processing of 1/2 times the end thickness on the most advanced part.

  The molten metal squeezing member 1 exhibits an effect of reducing surplus plating at a distance of 10 mm or less from the steel strip, and the effect increases as it approaches the steel strip. Although it is preferable that the molten metal squeezing member 1 and the steel strip are not in contact with each other, the molten metal squeezing member 1 is usually provided with a support roll 6 immediately below, and in the region from the support roll 6 to the plating bath surface, a steel plate is provided. Since vibration and warpage are small, the molten metal squeezing member 1 may be in contact with the steel strip if there is no wrinkle. The distance between the upper end of the molten metal squeezing member 1 and the plating bath surface is 10 mm or less, and the effect of reducing excess plating is manifested. The effect increases as it approaches the plating bath surface. It is desirable that the top end be as close as possible without protruding from the plating bath surface.

  Further, the present inventors form a flow toward the anti-steel strip side in the vicinity of the plating bath surface near the upper end portion of the anti-steel strip side of the molten metal drawing member 1 while observing the flow in the vicinity of the plating bath surface. As a result, it has been found that the drawing effect of excess plating is improved. Specifically, as shown in FIG. 1, a fluidizer having a suction port extending in the width direction facing the steel strip direction in the vicinity of the plating bath surface on the side opposite to the upper end of the molten steel drawing member 1 of the molten metal drawing member 1. 2 is installed, and the plating bath is sucked from this suction port by the power of the pump, and a flow toward the anti-steel strip side is formed in the vicinity of the plating bath interface on the anti-steel strip side upper end side of the molten metal drawing member 1. That's fine. However, if the suction speed (= flow toward the anti-steel strip side) is too slow, there will be no squeezing effect of excess plating, and if it is too fast, the flow of supplying molten metal plating, which decreases on the contrary, flows from the end of the steel strip to the center of the steel strip. Therefore, excess plating does not decrease. From such a viewpoint, the average speed at the suction port is preferably 5 to 30% of the plate passing speed. Moreover, it is preferable to flow the molten metal within a depth of 50 mm from the liquid level of the plating bath in a direction away from the steel strip.

  The above-described molten metal squeezing member 1 and the flow device 2 may be used independently or in combination.

  In order to clarify the position and shape of the molten metal squeezing member 1 shown in FIG. 2 and the effect of reducing the surplus plating amount by the flow device 2 shown in FIG. 1, the molten metal plating apparatus shown in FIG. It was installed in the line and the production experiment of the hot dip galvanized steel strip was conducted.

  The molten metal squeezing member 1 is opposed to both surfaces of the steel strip, and is attached to the end of the frame extended from the position control device by a servo motor provided outside the molten metal tank 9 by bolting, so that the distance from the steel strip can be easily controlled. In addition, the molten metal squeezing member 1 can be easily replaced.

  Each of the molten metal squeezing members had a height (vertical dimension of the cross-sectional shape), a width (horizontal dimension of the cross-sectional shape) of 50 mm, and a length (dimension in the width direction of the steel strip) of 2000 mm corresponding to the gas wiping nozzle. In Table 1 below, the shape of “triangle + angle R” has a radius of curvature of the upper end of the surface facing the steel strip of 5 mmR, and the “L-shaped” has a thickness of 7 mm, the surface of the surface facing the steel strip. The upper end curvature radius is 5 mmR, and the “crescent shape” has an upper surface curvature radius of 60 mmR and a lower surface curvature radius of 100 mmR. In the case of the “triangle” and “rectangular” shapes, the upper end on the side facing the steel strip is not chamfered (curvature radius 0 mmR).

  The flow device 2 includes a suction port below the molten zinc bath surface on the side of the upper end of the molten metal squeezing member 1 (on the side of the anti-steel strip), sucks molten zinc from the suction port with a pump, and the anti-steel strip near the bath surface. It was set as the structure discharged in a direction. The suction port height (steel strip running direction dimension) is 50 mm, the steel strip width direction length is 2000 mm, which is equivalent to a gas wiping nozzle, and the suction motor can be changed in several stages by changing the pump drive motor voltage. It is.

The manufacturing conditions of the hot dip galvanized steel strip are as follows: the slit gap of the gas wiping nozzle is 0.8 mm, the distance between the gas wiping nozzle and the steel strip is 8 mm, the height of the gas wiping nozzle from the hot galvanizing bath is 420 mm, and the hot galvanizing bath temperature is 460 ° C. The steel strip size to be used was 0.8 mm thickness × 1.4 m width, and the plating adhesion amount was 50 g / m ^{2 on} one side. The distance from the bath surface to the upper end of the gas wiping nozzle was fixed at 5 mm for the convenience of the apparatus. Table 1 shows other manufacturing conditions, the shape and position of the molten metal squeezing member, and the results of investigation of the amount of splash generated that is an indicator of product quality.

  The splash generation amount is a ratio of the steel strip length determined to have a splash defect in the inspection process to the steel strip length passed under each manufacturing condition, and includes a slight splash defect that does not cause a problem in practice.

  Examples 1 to 4 are examples using the triangular molten metal squeezing member of FIG. 2A, and the result was that the splash defects were reduced as the distance between the molten metal squeezing member and the steel strip was reduced. Compared with Comparative Example 1 in which the molten metal squeezing member was not used, the splash defect rate was reduced to approximately 1/13 in Example 1 in which the distance between the molten metal squeezing member and the steel strip was 0 mm (contact). Even in Example 4 in which the distance from the steel strip was 9 mm, the splash defect rate was improved by 15% compared to the comparative example. Although not shown in the examples, even when the molten metal squeezing member was changed to (b) to (d) in FIG. 2, the position of the molten metal squeezing member at which the effect of reducing the splash defect rate began to appear was hardly changed. Therefore, it is desirable that the distance between the molten metal squeezing member and the steel strip is 10 mm or less.

  Examples 5 to 7 are cases in which the shapes of the molten metal squeezing members are as shown in FIGS. The distance between the molten metal squeezing member and the steel strip was fixed at 3 mm in order to determine the effect of suppressing the steel strip accompanying flow according to each shape. As a result, Example 5 is equivalent to Example 2, Example 6 with a rounded corner is more effective than these, and Example 7 having a crescent shape is more effective and is 1/5 of Comparative Example 1. It was confirmed that the splash defect rate decreased until.

  In Example 8, the flow rate was used without using the molten metal squeezing member, and the suction speed was set to 10% of the plate passing speed. In this case, it was confirmed that the splash defect rate was about half that of Comparative Example 1.

  Examples 9 to 12 are cases where the molten metal squeezing members of Examples 2 and 5 to 7 and the flow device of Example 8 were used at the same time. In all the examples, it was confirmed that the splash defect rate was greatly improved to the same extent as in Example 1. This is because a synergistic effect is generated by the combined use of the molten metal squeezing member and the flow device.

  Comparative Example 2 is a case where the rectangular (height 50 mm × width 50 mm) molten metal drawing member described in Patent Document 1 is installed, and although the splash defect rate is lower than that of Comparative Example 1 and the effect is seen, Compared with the Example of this invention which installed the molten metal member prescribed | regulated by invention in the same position, there were many splash defect rates 2.5 to 4.5 times.

  In Example 13 and Comparative Example 3, the steel strip passing speed was increased to 4.0 m / sec, and Comparative Example 3 in which neither the molten metal squeezing member nor the flow device of the present invention was used was The generation was so large that the wiping nozzle was clogged quickly, so that the operation was impossible. On the other hand, Example 13 was able to operate at a quality level equivalent to the current level even after increasing the plate passing speed.

  The apparatus of the present invention can be used as a manufacturing facility for a hot-dip metal-plated steel strip that reduces the occurrence of splash and has an excellent surface appearance. Since the apparatus of the present invention can suppress the occurrence of splash even at the time of high-speed plate feeding, it can be used as an apparatus for manufacturing a molten metal plated steel strip excellent in surface appearance while maintaining high productivity.

  Moreover, the manufacturing method of the steel strip of this invention can be utilized as a manufacturing method of the hot-dip metal plating steel strip which reduces generation | occurrence | production of a splash and is excellent in surface appearance.

It is a schematic longitudinal cross-sectional view which shows one Embodiment of the hot-dip metal plating steel strip manufacturing apparatus of this invention. It is a longitudinal cross-sectional view explaining embodiment of the molten metal aperture | diaphragm | squeeze member installed in the molten metal plating steel strip manufacturing apparatus of this invention. It is a figure which shows a general molten metal plating apparatus. It is a longitudinal cross-sectional view which shows the molten metal throttle member of patent document 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molten metal throttle member 2 Flow apparatus 3 Steel strip 4 Gas wiping nozzle 5, 6 Support roll 7 Sink roll 8 Molten metal plating bath 9 Molten metal tank

Claims (9)

An apparatus for producing a molten metal-plated steel strip, in which gas is sprayed from a gas wiping nozzle onto the surface of a steel strip that is continuously pulled up from a molten metal plating bath, and the amount of plating on the surface of the steel strip is controlled. A molten metal drawing member having a length equal to or greater than the width of the steel strip disposed opposite to the steel strip on both sides of the steel strip below the liquid level, and a surface of the molten metal drawing member facing the steel strip and the steel strip The distance between the surface of the molten metal squeezing member is larger than the lower part and the surface of the molten metal squeezing member is not opposed to the steel strip (excluding the upper surface of the molten metal squeezing member) and the steel strip, An apparatus for producing a molten metal-plated steel strip, wherein an upper portion of the molten metal squeezing member is larger than a lower portion. The apparatus for manufacturing a molten metal-plated steel strip according to claim 1, wherein the upper end portion of the surface of the molten metal drawing member facing the steel strip is curved so that the distance from the steel strip increases as it goes upward. An apparatus for producing a molten metal-plated steel strip, characterized by being formed. 2. The apparatus for manufacturing a molten metal plated steel strip according to claim 1 , wherein a cross sectional shape of a vertical cross section perpendicular to the steel strip surface of the molten metal drawn member is a triangle. apparatus. The apparatus for manufacturing a molten metal-plated steel strip according to claim 1 , wherein a cross-sectional shape of a vertical cross section perpendicular to the steel strip surface of the molten metal drawn member is an inverted L-shape. Manufacturing equipment. 3. The apparatus for manufacturing a molten metal-plated steel strip according to claim 1 or 2, wherein a cross-sectional shape of a vertical cross section perpendicular to the steel strip surface of the molten metal drawing member is a cross-sectional curve of the upper surface of the molten metal drawing member and a molten metal drawing. Both of the cross-section curves of the lower surface of the member are convex toward the steel strip lifting portion side of the molten metal plating bath, and at least the thickness of the cross-sectional surface end side of the cross-section is directed toward the anti-bath surface end portion. An apparatus for producing a hot-dip metal-plated steel strip, characterized by being formed to decrease. In the apparatus for manufacturing a molten metal-plated steel strip according to claim 5, the cross-sectional curve of the upper surface of the molten metal squeezing member has an arcuate curved portion at least in a portion facing the steel strip lifting portion of the molten metal plating bath, The sectional curve of the lower surface of the molten metal squeezing member has an arcuate curved portion at least on the back surface of the portion corresponding to the steel strip lifting portion of the molten metal plating bath, and the curvature radius of the arcuate curved portion on the upper surface is an arc shape on the lower surface. An apparatus for producing a molten metal-plated steel strip, characterized by being smaller than the radius of curvature of the curved portion. An apparatus for producing a molten metal-plated steel strip, in which gas is sprayed from a gas wiping nozzle onto the surface of a steel strip that is continuously pulled up from a molten metal plating bath, and the amount of plating on the surface of the steel strip is controlled. On both sides of the steel strip below the liquid level of the steel strip has a molten metal drawing member having a length equal to or greater than the width of the steel strip, the vertical direction perpendicular to the steel strip surface. An apparatus for producing a hot-dip metal-plated steel strip, characterized in that the cross-sectional shape of the cross-section is an inverted L shape, and the surface facing the steel strip is parallel to the steel strip surface. In the manufacturing apparatus of molten metal plated steel strip according to any one of claims 1 to 7, further wherein the reaction in the steel strip side upper portion side, the depth within 50mm from the liquid surface of the plating bath of molten metal diaphragm member An apparatus for producing a molten metal-plated steel strip, comprising a flow device having a suction port extending in a width direction of the steel strip that causes the molten metal to flow in a direction away from the steel strip . A method for producing a molten metal-plated steel strip, comprising performing molten metal plating using the apparatus for producing a molten metal-plated steel strip according to any one of claims 1 to 8 .

Images