JP2005171336A - Hot dip metal plating method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot dip metal plating method and apparatus which allows to eliminate the increase of film thickness and defects in surface quality, e.g., caused by the sticking of splashes to a plating face, and can be operated at a plating line rate of ≤300 m per minute, with high production capacity. <P>SOLUTION: In the continuous plating equipment where a strip 1 is continuously fed to a hot dip metal pot 2 and is passed therethrough to plate the surface of the strip with hot dip metal, a blade wiper 6 confronted with both the surfaces of the strip and a pressure applying means 7 composed of a static pressure pad mechanism which is provided at the downstream side of the plating line in the blade wiper and increases the pressure of the outlet side part in the blade wiper, are provided for controlling the thickness of a plating metal film 10 stuck to the strip 1 taken out from the hot dip metal pot 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a molten metal plating method and equipment in an iron manufacturing process line, particularly a molten metal plating line for zinc or the like.

  In this type of molten metal plating line, the strip (steel plate), which has been kept at a high temperature by continuous pretreatment such as annealing, is generally passed through the sink roll in the molten plating bath (molten metal pot). In the rising process, the plating adhesion amount (molten metal thickness) is controlled and then cooled to room temperature with a predetermined cooling pattern.

  For example, as shown in FIG. 5, after the strip 100 is once drawn into the hot dipping bath 101, the direction is changed by the sink roll 102 disposed in the hot dipping bath 101, and the vertical direction passes through the support roll 103 in the bath. The excess of the molten zinc adhering to the surface of the strip 100 is controlled to a required plating adhesion amount by a gas blown from a pair of wiping nozzles 104 disposed opposite to the hot dipping bath 101. (See Patent Document 1). In FIG. 5, reference numeral 105 denotes a distance meter. Based on the measured value of the distance meter 105, the analysis device 106 obtains the vibration and shape of the strip 100. Based on this, the process computer 107 determines the distance between the strip 100 and the wiping nozzle 104. Control is performed so as to approach the limit of the range in which contact between the two can be avoided.

  As shown in FIG. 6, the strip 100 is subjected to a treatment such as surface cleaning in a pretreatment furnace, led to a hot dipping bath 101, and pulled up via a sink roll 102. 108 and the second hydrostatic pad 109 have their travel lines bent into an arc shape, and the excess molten zinc adhering to the strip 100 is attached to the strip entry side of each hydrostatic pad for controlling the amount of adhesion. It is scraped off by the gas from the nozzles 108a, 109a and controlled to a predetermined plating adhesion amount. The strip 100 is securely held by the static pressure generated by the gas jetted from the jet nozzles 108a and 109a for controlling the adhesion amount and the gas jet nozzles 108b and 109b provided on the outlet side of each pad, and does not vibrate. (See Patent Document 2).

Japanese Patent Laid-Open No. 7-180019 (FIG. 1) Japanese Patent Laid-Open No. 7-102354 (FIG. 1)

  By the way, in the plating method as described above, production of galvanized steel sheets has been generally performed at a strip running speed of up to about 150 m / min. In order to improve the productivity of such a molten metal plating line, it is necessary to increase the plating line speed. When the plating line speed, that is, the strip traveling speed is increased, it is necessary to increase the wiping capability by the gas wiper or the static pressure pad, and it is necessary to increase the gas injection force by reducing the distance between the strip and the nozzle in order to increase the capability. .

  However, in the above-described two conventional methods, when the strip running speed exceeds 150 m / min and the gas injection force becomes strong, as shown in FIG. The collision with the strong wiping gas (see the arrow in the figure) ejected from the wiping nozzle 104 etc. causes the liquid film 110 to collapse and a splash (droplet scattering) 111 is generated (see FIG. 7B). Splash 111 spreads to the wiper exit side and adheres to the plate surface, resulting in an increase in film thickness and surface quality defects. For this reason, there was a problem that the plating line speed could not be increased.

  Accordingly, an object of the present invention is to provide a high-productivity molten metal plating method and equipment capable of operating at a plating line speed of up to about 300 m / min, eliminating an increase in film thickness and surface quality defects such as adhesion of splash to the plating surface. Is to provide.

  In order to achieve the above object, the molten metal plating method according to the present invention is a continuous plating method in which a steel plate is continuously fed to a molten metal pot and passed through it to plate the molten metal on the surface of the steel plate. After passing the steel plate which came out from the blade wiper which opposes the both surfaces of the said steel plate, it is made to pass through the pressure addition means which raises the pressure of the exit side part of the same blade wiper.

  Further, the molten metal plating facility according to the present invention is a continuous plating facility for continuously supplying and passing a steel plate to a molten metal pot and plating the molten metal on the surface of the steel plate. In order to adjust the thickness of the molten metal to be attached, a blade wiper opposed to both surfaces of the steel sheet, and a pressure applying means provided on the downstream side of the plating line of the blade wiper to increase the pressure of the exit side of the blade wiper It is characterized by providing.

  Further, the pressure applying means has two or more air or gas injection ports on the upper and lower sides, and static pressure portions higher than the atmospheric pressure generated in a portion surrounded by the air or gas injection ports are formed on both sides of the steel plate. It is characterized by comprising a static pressure pad mechanism.

  Further, the pressure applying means is constituted by a gas wiper mechanism having a horizontally long single air or gas injection port in an air or gas supply chamber extending in the width direction of the steel plate.

  Further, the blade wiper is provided so that the gap can be adjusted, and the pressure applying means is provided so that the position can be adjusted in the horizontal direction and the vertical direction.

  Further, the air or gas injection port gap of the pressure applying means is provided to be adjustable.

  Further, the entire inclination of the pressure applying means or the angle of the air or gas injection port is provided to be adjustable.

  According to the molten metal plating method and equipment according to the present invention having the above-described configuration, the influence of splash is effectively avoided by scraping off the primary excess adhered molten metal by the blade wiper and under high pressure at the blade wiper exit side. In addition to the improvement in quality, the synergistic effect of pushing down the molten metal between the blade and the plate due to the pressure difference between the inlet side and the outlet side of the blade can increase the plating line speed and improve the production capacity.

  Further, the pressure applying means has two or more air or gas injection ports on the upper and lower sides, and static pressure portions higher than the atmospheric pressure generated in a portion surrounded by the air or gas injection ports are formed on both sides of the steel plate. Since it is comprised by a static pressure pad mechanism, there exists an advantage which can contain the splash which generate | occur | produces the vibration suppression effect of a steel plate, and is generated by the collision of air or a gas jet.

  Further, since the pressure applying means is constituted by a gas wiper mechanism having a horizontally long single air or gas injection port in an air or gas supply chamber extending in the width direction of the steel plate, the influence of splash can be achieved with a simple structure. Can be effectively avoided to improve the quality, and the plating line speed can be increased to improve the production capacity.

  Further, since the blade wiper is provided so that the gap can be adjusted and the pressure applying means is provided so that the position of the pressure applying means can be adjusted in the horizontal direction and the vertical direction, the installation position of the pressure adding means can be adjusted to the optimum position according to the gap adjustment of the blade wiper. Can be set or changed.

  Further, since the gap of the air or gas injection port of the pressure applying means is adjustable, the air or gas injection pressure can be optimally controlled.

  Further, since the overall inclination of the pressure applying means or the angle of the air or gas injection port is provided so as to be adjustable, the air or gas injection direction can be optimally controlled.

  Hereinafter, the molten metal plating method and equipment according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a side view of the vicinity of a plating adhesion amount control part of a molten metal plating line showing Example 1 of the present invention, and FIG. 2 is an enlarged cross-sectional view of the main part of FIG.

  In FIG. 1, a strip (steel plate) 1 is sent upward through a sink roll 3 in a molten metal pot 2, and is sent in a lateral direction from a top roll 4 provided above.

  In the figure, reference numeral 5 denotes a plating thickness control device provided facing both surfaces (front and back surfaces) of the strip 1 moving upward near the bath surface of the molten metal pot 2. The plating thickness control device 5 includes a blade wiper 6 provided at a height near the bath surface, and a non-contact pressure applying means 7 provided on the downstream side of the plating line close to the exit side of the blade wiper 6. And a non-contact strip damping means 8 provided on the downstream side of the plating line. This strip damping means 8 shows only one stage in FIG. 1, but it may be provided in a plurality of stages in the plating line direction.

  FIG. 2 shows a specific example of the plating thickness control device 5 only on one side of the strip 1, but in actuality, the strip thickness 1 is sandwiched and provided symmetrically. In FIG. 2, reference numeral 10 denotes a plated metal film that adheres to and rises on both surfaces of the strip 1 in the bath of the molten metal pot 2.

  In FIG. 2, the blade wiper 6 is formed of a heat-resistant metal or a ceramic material to which hot-dipped metal does not easily adhere, and is provided so as to be able to adjust the gap (gap).

  The pressure applying means 7 shows a case where a static pressure pad mechanism having both a pressure applying function and a vibration damping function is used, and is provided so as to be capable of adjusting the position in the horizontal and vertical directions with respect to the moving strip 1. This type of pressure applying means 7 includes two or more jet nozzles 12 and 13 which are provided in an air or gas supply chamber 11 extending in the width direction of the strip 1 and which are long in the width direction. A pressure-resistant wall 14 parallel to the surface of the strip 1 is provided between them, and air or gas injected from the upper and lower injection ports 12 and 13 hits the surface of the strip 1 and flows up and down to apply downward pressure along the plated metal film 10. At the same time, the static pressure portion 15 is generated and maintained within the space surrounded by the air flow, and works to dampen the strip 1 by balancing on both sides of the strip 1.

In the pressure applying means 7 shown in FIG. 2, the gaps b ₁ and b ₂ between the injection ports 12 and 13 can be adjusted, and the inclination of the pressure applying means 7 as a whole or the angles of the injection ports 12 and 13 can be adjusted. It is preferable to be configured as follows.

In this case, for example, when the strip plate 1 is operated at a speed of 300 m or less per minute, the lower injection port 13 and the blade wiper with respect to the gaps b ₁ and b ₂ between the upper and lower injection ports 12 and 13, respectively. 6 where L is the vertical distance from the upper end, and H is the gap from the injection ports 12 and 13 to the strip 1 surface, L is [(b ₁ + b ₂ ) × 30 or less], and H is [(b ₁ + b According to the present inventors, the downward flow of the jetted air flow effectively wipes and drops the excessively thick plated metal film 10 adhering to the surface of the strip 1 when adjusted by ₂ ) × 10 or less] It has been confirmed by experiments.

  In FIG. 2, illustration of the strip damping means 8 is omitted, but the strip damping means 8 may be provided with a static pressure pad type or an electromagnetic coil type which will be described in detail in the second embodiment.

  Since it is configured in this way, the strip 1 is moved upward from the sink roll 3 at a plate passing speed in the range of 300 m or less, for example. The strip 1 enters between the blade wipers 6 with an excessive amount of plated molten metal on both sides thereof, and excess adhered molten metal is temporarily scraped off in a regulated gap (gap) of the blade wiper 6. That is, the strip 1 passes through the blade wiper 6 with the plating layer having a slight excess thickness.

  Since the pressure at the outlet side of the blade wiper 6 is kept high by the downward gas flow by the pressure applying means 7, the plating melt at the outlet portion (A portion in FIG. 2) of the blade wiper 6 than when no pressure is applied. The metal flow rate is reduced. That is, the plating adhesion amount is reduced. Furthermore, since the flow rate of the molten metal is reduced also in the vicinity of the gas jet collision portion (B portion in FIG. 2) by the pressure applying means 7, a two-stage wiping effect is produced.

  At this time, the strip 1 moves upward while vibration is suppressed by the damping action of the static pressure portion 15 of the pressure applying means 7, and the molten metal flow flowing backward from the B portion is discharged along the upper surface of the blade wiper 6. Therefore, no liquid pool is generated in the A part. Further, the splash 10 a generated by the collision of the gas jet at the portion B is sealed by the gas jet from the upper injection port 12 of the pressure applying means 7 and is not released upward from the pressure applying means 7.

Therefore, the distance H between the pressure applying means 7 and the surface of the strip 1 and the vertical distance L between the upper end of the blade wiper 6 are about H = [(b ₁ + b ₂ ) × 10 or less (for example, b ₁ , When b ₂ = 0.5, 10 mm or less], L = [(b ₁ + b ₂ ) × 30 or less (for example, b ₁ , b ₂ = 0.5, 30 mm or less)] The strip 1 can be continuously formed with a uniform film thickness (plated metal film) free from surface quality defects such as splash marks.

  Further, in this embodiment, since the pressure applying means 7 has a vibration damping function, the dedicated strip damping means 8 shown in FIG. 1 can be omitted or the number of installations can be reduced.

  As a result, according to the present embodiment, the plating line speed can be greatly increased to provide a high-quality, high-productivity molten metal plating method and equipment that are not affected by the splash 10a.

  FIG. 3 is a side view of the vicinity of a plating adhesion amount control unit of a molten metal plating line showing Embodiment 2 of the present invention, and FIG. 4 is a side view of the vicinity of a plating adhesion amount control unit showing a modification of FIG.

  In this embodiment, a gas wiper mechanism having a single injection port is provided as the pressure applying means 7 in the second embodiment, and a static pressure pad mechanism (example of FIG. 3) or an electromagnetic damping mechanism (as shown in FIG. 3) is provided as the strip damping means 8. It is an example provided and provided with the example of FIG.

  As shown in FIGS. 3 and 4, the pressure applying means 7 includes a horizontally long single injection port 22 in an air or gas supply chamber 21 extending in the width direction of the strip 1. Thus, the position can be adjusted in the horizontal direction and the vertical direction, and the injection angle can be changed and supported.

  In FIG. 3, the injection port 22 is inclined at a certain angle, and the distance H to the strip 1 surface and the vertical distance L between the upper end of the blade wiper 6 are adjusted and provided in the same manner as in the first embodiment. Air or gas is jetted obliquely downward from the jet port 22 toward the strip 1 side to wipe the plated metal film 10 on the surface of the strip 1, and at the same time, the pressure near the exit side of the blade wiper 6 is increased, Along the upper surface of the blade wiper 6, it is pushed outward in the figure and returned to the bath of the molten metal pot 2.

  The static pressure pad mechanism 31 (example in FIG. 3) provided as the strip damping means 8 is configured so that the upper and lower air or gas injection ports 12 and 13, the pressure resistant wall 14, and the static pressure portion 15 surrounded by the strip 1 are disposed on both surfaces of the strip 1. The strip 1 is damped by balancing on the side.

  The electromagnetic damping mechanism 32 (example of FIG. 4) provided as the strip damping means 8 is composed of one or a plurality of electromagnetic coils provided to generate a magnetic field in a direction perpendicular to the strip 1. The strip 1 is damped by reversing the direction of the magnetic field and balancing the strength on both sides.

The pressure applying means 7 and the vibration damping means 8 are not limited to those described above. For example, the pressure applying means 7 is configured in a further different form, for example, the gap b ₃ of the single injection port 22 can be adjusted. Also good.

  Due to such a configuration, also in the case of the present embodiment, the distance H between the injection port 22 and the strip 1 of the pressure applying means 7 comprising the gas wiper mechanism, and the vertical distance L between the blade wiper 6 upper end and the injection port 22 are as follows. The adjustment is made in the same range as in the first embodiment.

  Accordingly, the pressure applying means 7 increases the pressure in the vicinity of the exit side of the blade wiper 6 by the air or gas jet flow jetted horizontally or obliquely downward from the jet port 22 to wipe the plated metal film 10 on the surface of the strip 1, The wiped molten metal and its splash 10a are pushed outward along the upper surface of the blade wiper 6 in the figure and returned to the molten metal pot 2 bath.

  While the strip 1 is damped by the strip damping means 8 comprising the static pressure pad mechanism 31 as shown in FIG. 3 or the strip damping means 8 comprising the electromagnetic damping mechanism 32 as shown in FIG. By passing the wiper 6 and the pressure applying means 7 adjusted to the distance H and the longitudinal distance L as described above, the same operation and effect as in the case of the first embodiment can be obtained.

It is a side view of the plating adhesion amount control part vicinity of the molten metal plating line which shows Example 1 of this invention. It is a principal part expanded sectional view of FIG. It is a side view near the plating adhesion amount control part of the molten metal plating line which shows Example 2 of this invention. FIG. 4 is a side view of the vicinity of a plating adhesion amount control unit that similarly shows a modification of FIG. 3. It is a side view near the plating adhesion amount control part of the conventional molten metal plating line. It is a side view near the plating adhesion amount control part of a different conventional molten metal plating line. It is explanatory drawing which shows the malfunction in the plating adhesion amount control part of the conventional molten metal plating line.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Strip 2 Molten metal pot 3 Sink roll 4 Top roll 5 Plating thickness control apparatus 6 Blade wiper 7 Pressure application means 8 Strip vibration control means 10 Plating metal film 10a Splash 11 Chamber 12 Injection port 13 Injection port 14 Pressure wall 15 Static pressure Part 21 Chamber 31 Static pressure pad mechanism 32 Electromagnetic damping mechanism

Claims (7)

  A continuous plating method in which a steel plate is continuously supplied to a molten metal pot and passed to plate the molten metal on the surface of the steel plate, and the steel plate coming out of the molten metal pot is passed through a blade wiper facing both sides of the steel plate. And a pressure applying means for increasing the pressure on the outlet side of the blade wiper.   A continuous plating facility for continuously supplying and passing a steel plate to a molten metal pot and plating the molten metal on the surface of the steel plate, in order to adjust the thickness of the molten metal attached to the steel plate coming out of the molten metal pot, A molten metal plating facility comprising: a blade wiper opposed to both surfaces of the steel sheet; and pressure applying means provided on a downstream side of the plating line of the blade wiper to increase the pressure of the outlet side of the blade wiper.   The pressure applying means has two or more air or gas injection ports on the upper and lower sides, and a static pressure higher than the atmospheric pressure generated in a portion surrounded by the air or gas injection ports is formed on both sides of the steel plate. The molten metal plating facility according to claim 2, comprising a pad mechanism.   3. The melting according to claim 2, wherein the pressure applying means is constituted by a gas wiper mechanism having a horizontally long single air or gas injection port in an air or gas supply chamber extending in the width direction of the steel sheet. Metal plating equipment.   The molten metal plating facility according to claim 2, 3 or 4, wherein the blade wiper is provided so that the gap can be adjusted, and the pressure applying means is provided so that the position can be adjusted in the horizontal direction and the vertical direction.   The molten metal plating facility according to claim 3, 4 or 5, wherein a gap between the air or the gas injection port of the pressure applying means is adjustable.   The molten metal plating facility according to claim 3, 4, 5, or 6, wherein the entire inclination of the pressure applying means or the angle of the air or gas injection port is adjustable.

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