JP4772567B2 - Hot-dip cooling system - Google Patents

Description

  The present invention relates to an apparatus for cooling a hot-dip galvanized wire used for solidifying an unsolidified hot-dip galvanized layer on the surface of an iron wire by pulling the iron wire vertically from a hot-dip galvanizing bath when producing a galvanized iron wire (steel wire). The present invention relates to a cooling device for a hot dipped wire that can hold a coolant without flowing out, leaking, or dripping vertically downward from a bottom opening for a wire provided in the cooling device.

  In order to impart corrosion resistance to an iron (steel) wire used in a harsh corrosive environment, the iron wire is generally passed through a hot dip galvanizing bath and the surface is galvanized. In hot dipping, generally iron (steel) wire is cleaned by cleaning, degreasing, etc., then fluxed as necessary, then immersed in a hot dipping bath, and the iron wire is pulled up vertically from the hot dipping bath. The method of winding after cooling is carried out. Among them, in order to obtain better corrosion resistance, it is most effective to increase the amount of zinc adhered per unit surface area.

  In the hot dip galvanizing process, in order to increase the zinc adhesion amount, it is necessary to increase the plating adhesion amount by increasing the pulling speed of the iron wire from the zinc bath, but as the adhesion amount increases, vibration, winding It becomes easy to be affected by slipping of the take-off machine, and defects on the surface such as dripping of molten zinc on the surface, irregularities, nodes, spirals, etc. are likely to occur.

  As a countermeasure, it is effective to perform primary cooling before the unsolidified hot-dip galvanized layer adhering to the iron wire becomes unstable due to disturbance, and to form a smooth solidified zinc shell that can withstand deformation on the surface. In the conventional direction of cooling with jet water from the lateral direction, if the position of the cooling device is too low, unsolidified zinc is pushed to the opposite side by the water pressure, resulting in uneven thickness or streaky irregularities along the water flow. It tends to occur. On the other hand, if the cooling device is set too high, surface disturbance due to line slip, vibration, etc. is likely to occur as described above. Since the installation height of this cooling water is affected by the wire speed, hot dip galvanizing bath temperature, wire diameter, etc., it is necessary to change the optimum position depending on the wire diameter and the wire speed.

  Various cooling devices for hot-dip plated wires without primary cooling have been proposed so far, and there are cooling devices that use liquid, gas, mist or the like as a refrigerant. As a cooling device using liquid (cooling water) as a refrigerant, for example, a hole thicker than the line to be cooled is provided at the bottom of a cylindrical cooling water container, and air is discharged upward through a gap between the line passing through the hole and the hole. The cooling water is forcedly circulated from the atmospheric pressure by a cooling device (for example, see Patent Document 1) that introduces a line into still water while preventing dripping from the cooling water hole due to its action, or a cooling water circulation pump. A cooling device that prevents leakage of cooling water downward by continuously introducing outside air into the chamber kept at a low pressure through the gap between the bottom wire introduction port and the wire is proposed (for example, see Patent Document 2). Has been.

However, in the case of these cooling devices, the high-pressure air discharged upward and the water that flows out downward in opposition thereto are unstable in time in the gap between the line inlet of the cooling tank (cooling water container) and the line. Therefore, when the plating adhesion amount is 300 g / m ² or more, the surface is disturbed and it is very difficult to obtain a smooth surface.

  In addition, as a cooling device using gas or mist as a coolant, for example, by adjusting the spray pressure by setting the angle between the gas or mist spray direction and the line to 10 to 45 °, uneven plating and sagging can be prevented. In a cooling device (for example, see Patent Document 3) or in a cylindrical chamber, the cooling gas is flowed upward in parallel with the axial direction of the line to be cooled to prevent the plating from sagging and to secure the necessary zinc adhesion amount An apparatus (for example, see Patent Documents 4 and 5) has been proposed.

  However, in the case of these cooling devices, since the refrigerant is a gas or mist, even if the material is passed at the minimum linear speed necessary for operation in order to secure the zinc adhesion amount, a stable adhesion amount and a cooling rate can be obtained. There is a problem that it cannot be obtained, and it is difficult to obtain a hot-dip galvanized iron wire having good surface properties.

Japanese Utility Model Publication No.57-13880 JP-A-6-81107 JP-A-4-183844 Japanese Patent Laid-Open No. 10-60615 JP 2000-45056 A

  The present invention solves the above-mentioned problems, prevents the defects of the plating surface during cooling of the plating wire, and opens the wire from the vertically downward to the still water, which is indispensable for securing the amount of plating adhesion per unit area, and opening. It is an object of the present invention to provide a cooling device for a hot dipped wire that prevents the cooling water from flowing out, leaking, or dripping in the vertical direction.

  The present invention has been made to solve the above problems, and the present inventor has provided a cylindrical rotating body at the bottom line inlet of the cooling water holding tank, and the cooling water flowing down from the inlet is rotated by the rotating body. By collecting along the outer periphery of the lower edge, the hot-dip plated wire passing through the cylindrical rotating body can be brought into contact with undisturbed cooling water, resulting in a hot-plated wire with good surface properties. As a result, the present invention has been completed.

  The gist of the present invention is as follows.

  (1) It has a cooling water holding tank having an opening on the bottom surface, and rotates at an angular velocity of 5 rotations / second or more while holding a gap of 1 mm to 4 mm at an interval from the plating wire at the bottom surface opening. Cooling of a hot dipped wire characterized by having a cylindrical rotating body having a downwardly convex rotationally symmetric surface and a collecting mechanism for collecting cooling water along the outer periphery of the lower edge of the rotating body apparatus.

  (2) The cooling apparatus for a hot dipped wire according to (1), wherein the cylindrical rotating body has a shape in which an upper portion has the same inner diameter and a lower portion has an inner diameter that increases downward.

  (3) The cooling apparatus for a hot dipped wire according to (1) or (2) above, wherein the cylindrical rotating body has irregularities or fins on the inner surface, outer surface, or both surfaces.

  (4) The hot dipped wire cooling device according to any one of (1) to (3), wherein the cylindrical rotating body has a rotating mechanism that can be rotated by power.

  (5) The collecting mechanism for collecting the cooling water has a hollow donut-like shape surrounding an outer peripheral portion of a lower edge portion of the rotating body. Cooling system.

According to the present invention, in a cooling water holding tank having an opening on the bottom surface, the cooling water is not leaked or dropped downward in the vertical direction as in the prior art, and the cooling water without disturbance is linear from the opening at the bottom. The application of the present invention makes it possible to stabilize a hot dip galvanized iron wire having a good surface property even when the coating weight is 300 g / m ² or more. The industrial effect is extremely remarkable.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an outline of a hot dip galvanizing production line. In hot dip galvanization, as shown in FIG. 1, an iron (steel) wire 1 is dipped in a hot dip galvanizing bath 2 and pulled up with the sinker 3 changing the direction of travel vertically upward to form an unsolidified plated layer. The hot-dip plated iron wire passes through the cooling device 5 through the antioxidant gas chamber 4 and solidifies the unsolidified plating layer with the cooling water in the cooling device. Thereafter, the direction is changed again by the top roller 6, and it proceeds to the winding device and is wound on the coil.

In hot dip galvanized wire, it is required to increase the amount of zinc deposited per unit surface area in order to obtain better corrosion resistance. However, when the adhesion amount of zinc increases, for example, when the adhesion amount of plating is 300 g / m ² or more, defects on the plating surface such as uneven thickness, sagging, unevenness, and nodes of the plating surface are likely to occur.

  When the present inventor investigated the cause of the plating surface failure, it was caused by cooling water disturbance at the bottom opening for the passage of the cooling water holding tank, leakage of cooling water from the opening, or dripping. I found out.

  Therefore, we conducted earnest research on a cooling device for hot-dip plated wire that does not cause disturbance of cooling water at the bottom opening, leakage or dripping of cooling water from the opening, and defects in the plating surface. By providing a cylindrical rotator at the bottom opening (line inlet) of the steel and collecting cooling water flowing down along the outer periphery of the lower end edge of the rotator, a hot-plated wire with good plating surface properties can be obtained. As a result, the present invention has been completed.

  FIG. 2 is a longitudinal sectional view of a hot-dip plated wire cooling apparatus provided with the rotating body of the present invention, and FIG. 3 is a view showing an outline of the rotating body arranged in the hot-dip plated wire cooling apparatus.

  As shown in FIG. 2 and FIG. 3, in the apparatus for cooling a hot-dip plated wire according to the present invention, a hot-plated wire passage opening (wire inlet) 8 is provided at the bottom of the cooling water holding tank 7 and penetrates the opening 8. A cylindrical rotating body 9 is installed.

  A pulley 10 is provided on the upper portion of the rotating body 9, and the rotating body can be rotated via a belt 11 hung on the pulley by power. Since the plating wire 12 passes through the center of the cylindrical rotating body, the plating wire and the rotating body are not physically in contact with each other. In addition, as a rotating mechanism of the rotating body, power can be transmitted by a gear and rotated, and the rotating mechanism is not particularly limited.

  The cooling water that flows down from the cooling water holding tank 15 that holds the cooling water 14 supplied from the cooling water pipe 13 and is sandwiched in the gap between the rotating body 9 and the plating wire 12 starts to flow vertically downward due to gravity. However, if the gap between the inner surface of the rotating body and the outer surface of the plating wire in the opening is less than 1 mm, the flow of the cooling water easily shifts to turbulent flow, and as a result, unsolidified molten zinc is disturbed and the surface of the plating wire is roughened.

  Further, if the gap is more than 4 mm, the gravity in the vertically downward direction is superior to the wetness with the wall of the rotating body, and the cooling water is separated as water droplets from the inner surface of the rotating body and falls vertically downward. For this reason, in this invention, the space | gap of the rotary body 9 and the plating wire 12 in an opening part is prescribed | regulated as 1 mm thru | or 4 mm.

  The rotating body 9 is a trumpet-shaped rotationally symmetric body that protrudes downward, with the inner surface in the vertical direction in the vicinity of the opening, and gradually tilting horizontally toward the lower edge of the rotating body. That is, it is a rotationally symmetric body having the same inner diameter at the upper part of the rotating body, but with the inner diameter expanding toward the lower part at the lower part. Due to the shape of the rotating body, the cooling water introduced into the wall of the rotating body in the vertically downward direction at the opening portion smoothly changes its flow direction, and is difficult to be detached and dropped while flowing along the inner surface of the rotating body.

  Cooling water that has been introduced into the rotating body from the opening and started to flow along the surface receives viscous friction from the rotating body, and gradually changes its flow direction to the circumferential direction of the rotating body. Rotate with the same angular velocity. At this time, as it goes downward, it approaches the speed of the rotating body wall, and at the same time, it receives an inertial force (centrifugal force) outward from the rotating shaft and is pressed against the rotating body wall.

  However, when the rotational speed is less than 5 revolutions / second, it is difficult to give sufficient angular velocity to the cooling water flowing along the inner surface of the rotating body, and it is separated from the inner surface of the rotating body and falls vertically. Will occur. For this reason, in this invention, the rotational speed of the rotary body was 5 times / second or more. The upper limit of the rotational speed is not particularly limited, but is preferably in the range of 5 to 20 times / second.

  The cooling water that flows downward along the inner surface of the rotating body and is given a flow velocity in the circumferential direction by the rotation reaches the lower edge of the rotating body and separates in the tangential direction. The fluid collecting mechanism 15 is attached so as to surround the outer peripheral portion of the lower edge portion of the rotating body, and the cooling water scattered and separated in the horizontal direction is collected. That is, the fluid collecting mechanism 15 that collects the cooling water has a hollow donut shape and surrounds the outer peripheral portion of the lower edge of the rotating body. The collected cooling water can be discharged through a pipe.

  By providing unevenness or fins 16 and other protrusions downward from the position where the inner diameter of the rotating body starts to expand from the vertical direction, an apparently large viscous resistance is given to the cooling water, so that the centrifugal force outwards the rotating body more effectively. Can be given. As the fin 16, for example, a fin shape such as an L-shaped section, a C-shaped section, or an I-shaped section is preferable.

  The rotating body 9 is fitted to the cooling water holding tank 7 so that it can rotate smoothly. Even if cooling water leaks at this fitting part, it reaches the lower end edge along the outer surface of the rotating body by the action of centrifugal force, and the cooling water is repelled to the outside in the horizontal direction. Presence or absence does not matter. If necessary, the outer surface of the rotating body or both the outer surface and the inner surface can be provided with unevenness or fins or other protrusions in the same manner as the inner surface. This makes it possible to effectively collect the cooling water that has leaked to the outer surface of the rotating body. For this reason, it is possible to prevent the leakage and dripping cooling water from coming into contact with the hot-dip galvanized wire in the middle of pulling and causing surface quality defects as in the prior art.

  Although the hot dip galvanized wire has been specifically described above, the present invention can also be applied to cooling of a plated wire other than the hot dip galvanized wire or cooling of a wire that requires cooling.

  Hereinafter, the present invention will be described based on examples. In addition, this Example demonstrates concretely along an example, The content of this invention is not limited.

The cooling test of the hot dip galvanized wire was carried out using the hot dip galvanized wire cooling device provided with the rotating body shown in FIGS. As the plating wire, a hot rolled material of 5.5 mmφ of JIS SWRM6 was used, and an iron wire cold-drawn to 4.0 mmφ was used. The drawn wire was annealed and then annealed, pickled with hydrochloric acid, washed with water, passed through a flux of aqueous ammonium chloride, dried in a blower, and immersed in a 450 ° C. molten pure zinc bath. The line speed was 30 m / min, the immersion time in the molten zinc bath was 10 s, the bath surface of the plated wire pulling portion was sealed with nitrogen, and a plated iron wire with a plating adhesion amount of 320 g / m ² was produced.

  In the cooling test, the surface property of the plating and water leakage were investigated by changing the distance between the plating wire and the rotating body and the rotating speed of the rotating body.

The test conditions and results are shown together in Table 1. As can be seen from Table 1, Examples 1 to 6 of the present invention have an appropriate distance between the plating wire and the rotating body, and the speed of the rotating body is sufficient. Therefore, there was no water leakage from the cooling water holding tank opening, and a smooth surface plated wire could be manufactured in a stable state.

  Comparative Example No. 7-9 and no. Nos. 14 and 15 are examples in which the rotation speed of the rotating body is slow, so that a sufficient circumferential speed cannot be given to the cooling water, and water leaks from the gap. Comparative Example No. Nos. 10 and 12 are examples in which the cooling water is disturbed because the distance between the plating wire and the rotating body is too narrow, and as a result, the surface properties of the plating wire are rough. On the contrary, Comparative Examples 11 and 13 are examples in which the distance between the plating wire and the rotating body is too wide, so that the cooling water leaves as water droplets and leaks vertically downward.

It is the figure which showed the outline of the hot dip galvanization production line. It is a longitudinal cross-sectional view of the cooling apparatus of the hot dipped wire provided with the rotary body of this invention. It is a figure which shows the outline | summary of the rotary body arrange | positioned in the cooling apparatus of the hot dipped wire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Iron (steel) wire 2 Hot-dip galvanizing bath 3 Sinker 4 Antioxidant gas chamber 5 Cooling device 6 Top roller 7 Cooling water holding tank 8 Opening 9 Rotating body 10 Pulley 11 Belt 12 Plating wire 13 Cooling water piping 14 Cooling water 15 Fluid Collection mechanism 16 Fin

Claims (5)

  It has a cooling water holding tank with an opening at the bottom, and rotates at an angular velocity of 5 rotations / second or more while holding a gap of 1 mm to 4 mm at an interval from the plating wire at the bottom opening. An apparatus for cooling a hot dipped wire, comprising: a cylindrical rotating body having a rotationally symmetric surface; and a collecting mechanism for collecting cooling water along an outer periphery of a lower end edge of the rotating body.   2. The hot dipped wire cooling device according to claim 1, wherein the cylindrical rotating body has a shape in which an upper portion has the same inner diameter and a lower portion has an inner diameter that increases downward. 3.   The apparatus for cooling a hot dipped wire according to claim 1 or 2, wherein the cylindrical rotating body has irregularities or fins on an inner surface, an outer surface, or both surfaces.   The said cylindrical rotating body has a rotation mechanism which can be rotated with motive power, The cooling apparatus of the hot-dip plated wire in any one of Claims 1-3 characterized by the above-mentioned.   The cooling device for a hot dipped wire according to claim 1, wherein the collecting mechanism for collecting the cooling water has a hollow donut shape surrounding an outer peripheral portion of a lower edge portion of the rotating body.

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