JPH10328737A - Method for cooling hot rolling coil and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly cool a series of coils and each coil, and to immediately ship the coil without storing them by blowing a cooling air from the lower side of a hot rolling coil toward the side surface of the coil and joining the cooling air to a hot air stream generating along the side surface of the coil. SOLUTION: Ventilation ducts 3 are arranged along a coil series 2 on both sides of the coil series 2 arranged with plural numbers of coils 1. The outside air is introduced from ventilation fans 4 installed at the beginning ends of respective ventilation ducts 3. Jetting nozzles pointing to the coil 1 are arranged on both side faces of the ventilation duct 3 by at least, three, for example, 5a to 5d are arranged on every coil 1, and the coil 1 is cooled by blowing the air to the coil 1. In the ventilation duct 3, it is important that the static pressure of the air flow inside the duct 3 is made uniform from the beginning end to the finishing end of the ventilation duct 3. Therefore, the blowing amount of the air onto the coil 1 can be made same between the total coil 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cooling a hot-rolled coil wound around a coil after hot rolling.

[0002]

2. Description of the Related Art A hot-rolled coil (hereinafter, simply referred to as a "coil") after hot rolling is left on a coil yard of a hot rolling factory or on a floor of a coil warehouse, and the room temperature and coil temperature in the factory or warehouse are reduced. It was cooled over time using the difference from the temperature. However, when the temperature difference between the coil and its surroundings is small and it takes a long time to cool the coil, various techniques have been developed for forcibly cooling to shorten the cooling time.

For example, JP-A-63-216927 discloses that a cooling yard floor is connected to an outdoor air intake.
An appropriate number of airway grooves are provided, and a plurality of direct-flow wind guide plates created by a large fan installed for each groove are provided in these grooves, and cooling between the grooves is performed. Guide cold air to each of the coil rows after hot rolling, arranged on the yard floor,
A method for forced air cooling is disclosed.

[0004]

However, in the above proposal, since the air used for cooling is not directed to the side surface of the coil, the heat removal efficiency is low and the cooling time is long. In addition, since the cool air is harder to reach as the coil gets farther from the large fan, the cooling between the coils in the coil array becomes uneven, and the wind speed on the surface of each coil is made constant by using an induction plate. Is very difficult, so that the cooling in each coil becomes non-uniform, and there is a disadvantage that the cooling time tends to vary greatly. Furthermore, since an airway groove is required, an enormous investment cost is required when installing the equipment.

Accordingly, the present invention is to provide a cooling method and apparatus for achieving uniform cooling in each coil and further in the coil array at a low cost.

[0006]

Means for Solving the Problems The inventors of the present invention have proposed a blower having a plurality of coils arranged on the floor of a coil yard or a coil warehouse of a hot rolling factory and arranged along the rows. In order to cool the coil by blowing air from the blower fan into the duct and blowing air to the coil from the nozzle installed with each coil directed from the blower duct,
By blowing air to the side of the coil with a large heat transfer surface, the cooling efficiency increases, and by optimizing the blowing angle of the air, the rising speed of the hot air flow on the side of the coil becomes constant. The present inventors have found that the present invention is effective for achieving uniform cooling, and based on such findings, have completed the present invention.

That is, according to the present invention, cooling air is blown from below the hot-rolled coil toward the side surface of the coil, and the cooling air is joined to a hot air flow generated along the side surface of the coil. And cooling the surface of the coil.

Further, according to the present invention, for a coil row in which a plurality of coils are arranged, air is fed into a ventilation duct arranged along the row, and a plurality of coils are installed to face each coil from the ventilation duct. When air is blown from the nozzle to the coil to cool the coil, the amount of air blown to the coil is the same for all coils, and air is blown so that the rising flow of air rising from the side of the coil is uniform. The method of cooling a coil, characterized by spraying water. In particular, it is advantageous to blow air to an intermediate region between the inner peripheral surface and the outer peripheral surface of the coil.

In the present invention, it is preferable that the cooling air is blown such that the average of the rising speed of the hot air flow combined with the cooling air on the side surface of the coil is at least 1 m / s. Here, the rising speed is a measured speed of the rising flow flowing within 30 mm from the coil side surface.

Next, in carrying out the cooling method of the present invention, on both sides of a coil row in which a plurality of coils are aligned,
Blowing ducts are respectively arranged along the coil rows, a blower fan is installed at the beginning of the blowing ducts, and an injection nozzle directed from the blowing duct to each coil side face of the coil row is directed to at least three sides of one side of each coil. A cooling device for the coil, wherein the blower duct has a configuration in which the static pressure of air flowing through the inside of the duct is equal from the start end to the end of the duct, and the injection nozzle has an inner peripheral surface of the coil. A coil cooling device characterized by being provided so as to be directed to an intermediate region with the outer peripheral surface can be used.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a coil cooling device according to the present invention has ventilation ducts 3 arranged on both sides of a coil array 2 in which a plurality of coils 1 are arranged. Then, outside air is introduced into the blower duct 3 from a blower fan 4 installed at the beginning of each blower duct 3. on the other hand,
As shown in FIG. 2, at least three injection nozzles 5 directed to the coils 1 of the coil array 2, and in the illustrated example, four injection nozzles 5 a to 5 d are provided on both side surfaces of the air duct 3. And air is blown from these injection nozzles 5 to the coil 1 to cool the coil.

Here, it is important that the ventilation duct 3 has a structure in which the static pressure of the air flowing through the inside of the ventilation duct 3 is uniform from the beginning to the end of the duct. That is, as shown in FIG. 2, by gradually decreasing the inner diameter from the start end to the end, the static pressure of the outside air introduced through the blower fan 4 in the blow duct 3 is reduced from the start end to the end of the blow duct 3. As a result, the static pressure on the inlet side of all the injection nozzles 5a to 5d was made the same. Therefore, the static pressure of the air flowing in the duct is equalized in the duct, and the amount of air blown to the coils can be made equal among all the coils. In addition,
In order to make the amount of air blown to the coil the same for all coils, in addition to means for gradually reducing the inner diameter of the air duct 3, a damper is provided in the duct to adjust the degree of opening, and similarly, The static pressure of the air flowing therethrough is equalized in the duct, and the same amount of air blown to the coils is achieved between all the coils.

As shown in FIG. 3, the injection nozzles 5a to 5d are formed so that the opening width t and the elevation angle α with respect to the coil 1 are different from each other. 2 and, as shown in FIG.
The amount of rise of the high-temperature air rising from the side surface can be effectively utilized, and air blowing with uniform rising speed of the hot air flow on the coil side surface is realized, so that the coil 1 is cooled very efficiently. It becomes possible.

For example, the opening width t and the elevation angle α of the injection nozzle 5 are preferably set as follows. As shown in FIG. 3, under the condition that the nozzle injection speed is 15 m / s or more, the flow distribution ratio of the injection nozzles 5a: 5b: 5c: 5d is approximately 2: 3: 1: 2. To decide. The opening shape was rectangular.

Elevation angle α: The contact point between the coil and a straight line extended from the center of each nozzle according to the elevation angle is changed in accordance with the change in the coil diameter D and the distance L between the duct and the coil, as indicated by ● in FIG. The elevation angles α _{a to} α _d of each nozzle are determined so as to satisfy the following expressions (1) to (4). Serial ^{_{α a = tan -1 {(D}} / 2-h a) / L} ---- (1) α b = tan -1 {(D-d 1/2-h b) / L} --- -(2) α _c = tan ^-1 {(d ₁ / 2−h _c ) / L} ---- (3) α _d = tan ⁻¹ {(D / 2−h _d ) / L}- - (4) where, d _1: nozzle thickness _{h a, h b, h c} , h d: height to the nozzle base in the duct (see FIG. 3) L: distance between the ventilation duct side and the coil

It should be noted that there is no problem even if the contact slightly fluctuates as long as the rising speed of the air rising along the surface of the coil side satisfies a condition of keeping 3 to 5 m / s described later. Preferably, ● mark, the intermediate coil thickness d _1.
This is because, if a mark is placed at this position, the air flow is distributed almost uniformly around the mark.

Further, although the mark ● shown in FIG. 5 changes according to the coil diameter D and the coil width W, when the nozzle elevation angle is fixed, the above-described coil size is most frequently used in the product configuration. If the nozzle elevation angle is determined by the equations (1) to (4), the coil diameter D is ± 500 mm and the coil width W is
Is changed by about ± 1000 mm, the rising speed of the air rising along the coil side surface is maintained at 3 to 5 m / s,
It has been verified that a predetermined cooling capacity can be obtained.

That is, in the present invention, in order to perform effective cooling using a high-temperature air rising flow (draft),
The rising speed of the air rising along the coil side surface is 5
m / s or less. This is because, as shown in FIG. 7, when the speed exceeds 5 m / s, the cooling effect is saturated, and the running cost increases as the ascending flow velocity increases. Furthermore, it can be said that it is more preferable to control the speed around 3 m / s. Further, if the speed is less than 1 m / s, the condition becomes substantially the same as the condition of natural cooling without using a fan, so that 1 m / s or more is required. The speed of the upward flow is a value measured within 30 mm from the coil surface at the eight measurement points shown in FIG.

Here, at least three injection nozzles 5 are provided on each side of each coil, as shown in FIGS.
The air injected from the injection nozzle rises by the draft on the coil surface in each of the regions b and c, but the cooling at the portion 5b in FIG. 5 can be achieved by utilizing the draft upward flow at the portion 5c. Thus, an example of arranging three injection nozzles is the nozzle 5b of the four types shown in FIG.
It is enough to remove 3 and arrange 3 of 5a, 5c, 5d. The conditions for determining the opening width t and the elevation angle α are as described above.

In the illustrated example described above, the air blow duct 3 is installed on the floor on which the coil 1 is mounted, which is the lowest cost structure. However, the air blow duct 3 is installed under the floor or under the half floor, Conversely, the mounting position of the coil 1 is made higher than the floor, for example, and the vertical distance between the blower duct 3, that is, the injection nozzle and the coil is relatively increased, and the elevation angle α of the injection nozzle is increased to blow air. By doing so, it is possible to promote the rise of the high-temperature airflow from the coil side surface.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Using the coil cooling apparatus shown in FIGS. 1 to 3, six coils having a coil width of 1200 mm and a coil diameter of 2000 mm are arranged in a row as shown in FIG. The air was supplied to the air duct 3 having a length of 12000 mm from the air blow fan 4 at 240 m ³ / min (average temperature: 35 ° C.) to cool the coil. The ventilation duct 3 has a rectangular cross section, and its inner diameter is kept constant in the width direction, while its height is gradually reduced from 600 mm at the start end to 150 mm at the end end. As a result, as shown in Table 1, the air flow distribution results for each coil were almost the same among the coils. In addition, in Table 1, coil Nos. 1 to 6 were set in order from the starting end side of the ventilation duct 3.

[0022]

[Table 1]

The specifications of the injection nozzles installed corresponding to the respective coils are as shown in FIG. 3, and the intervals between the nozzles 5a and 5d and the nozzles 5b and 5c are as shown in FIG. As a result, the average wind speed on the coil surface was approximately 3 m / s. The distance between the side surface of the air duct 3 and the coil was 300 mm.

Under the above conditions, the time required for cooling the maximum temperature portion of each coil to 50 ° C. or less, which enables direct shipment of the coil, was investigated. The cooling of all the coils was completed within three days. did. At this time, no difference was observed in the cooling completion time between the coil arranged at the beginning and the coil arranged at the end of the air duct. Incidentally, when the same coil was cooled by conventional standing cooling, 5 to 6
It took time for the day. Here, the reason why the cooling completion temperature of the coil is set to 50 ° C. is that it is a maximum temperature at which the coil can be directly shipped, for example, an upper limit temperature at which a surface defect does not occur in a skin pass performed by unwinding the coil.

[0025]

According to the present invention, uniform cooling can be realized at low cost in each coil and further in the coil array, and it is not necessary to store the coil in a warehouse or the like for a long time. Shipment is possible, and the cost of logistics costs is significantly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a cooling device of the present invention.

FIG. 2 is a side view showing a cooling device of the present invention.

FIG. 3 is a schematic view of an injection nozzle.

FIG. 4 is a schematic diagram illustrating blowing of air from an injection nozzle.

FIG. 5 is an explanatory diagram of a nozzle elevation angle.

FIG. 6 is an explanatory diagram of an upward flow of air along a draft.

FIG. 7 is a graph showing a relationship between a coil surface wind speed and a cooling heat transfer coefficient.

FIG. 8 is an explanatory diagram showing measurement points of an upward air flow.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coil 2 Coil row 3 Blow duct 4 Blow fan 5a-5d Injection nozzle

Claims (4)

[Claims] 1. A cooling air is blown from below a hot-rolled coil toward a side surface of the coil, and the cooling air is combined with a hot air flow generated along the side surface of the coil to form a coil surface. And cooling the hot rolled coil. 2. A hot-rolled coil row in which a plurality of hot-rolled coils are aligned, air is blown into a blow duct arranged along the row, and each hot-rolled coil is set to be directed from the blow duct. When cooling the hot-rolled coil by blowing air from multiple nozzles to the side of the hot-rolled coil, the amount of air blown to the hot-rolled coil should be the same for all the coils, and the air should be set up from the side of the hot-rolled coil. A method for cooling a hot-rolled coil, characterized by blowing air so that the rising flow of the rising air is uniform. 3. An average rising speed of a hot air flow combined with cooling air on a side surface of the coil is at least 1 m / s.
The cooling method according to claim 1, wherein the cooling air is blown so as to satisfy the following. 4. A ventilation duct is arranged on each side of a hot-rolled coil row in which a plurality of hot-rolled coils are arranged along the hot-rolled coil row, and a blower fan is installed at a start end of the blower duct. A hot-rolled coil cooling device in which at least three jet nozzles directed from a duct to each coil side surface of a hot-rolled coil row are provided for each hot-rolled coil, wherein the blower duct has a structure in which air flowing therethrough is provided. A cooling device for a hot-rolled coil, characterized in that the static pressure is made uniform from the beginning to the end of the duct, and the injection nozzle is provided so as to be directed to an intermediate region between the inner peripheral surface and the outer peripheral surface of the coil. .