JPH08192218A - Cooling device for hot rolled steel strip - Google Patents

Abstract

PURPOSE: To precisely control the cooling of a steel strip, prevent the dispersion of a material quality and improve the quality of the steel strip by making it possible to lower a spray nozzle at the time of the high pressure supply of cooling water, and making it possible to elevate the spray nozzle at the time of the low pressure supply of the cooling water. CONSTITUTION: This cooling device is equipped with a pipe lamina flow nozzle 3 whose cooling capacity is almost constant and a spray nozzle 13 capable of controlling the cooling capacity. Low pressure cooling water is supplied to the pipe lamina flow nozzle from a cooling water supply pipe 2, and is made to flow down on a steel strip 15, which is passed through a hot run table after a hot finish rolling, and the steel strip 15 is cooled. When elevating a rack 8 by a fluid pressure cylinder 6, the spray nozzle 13 is elevated to stop the flowing-out of the low pressure cooling water. When supplying high pressure cooling water to the cooling water supply pipe 2, the flowing-down of the cooling water from the pipe lamina flow nozzle 3 is stopped by the operation of a check valve 4, and when lowering the rack 8, the cooling water is jetted from the spray nozzle 13. In this way, the cooling of the steel strip 15 can be precisely controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for hot rolled steel strip.

[0002]

2. Description of the Related Art As is well known, a hot-rolled steel strip is produced by hot-rolling a heated steel strip, then hot-finishing it to a predetermined thickness, and then passing it through a hot run table. Cooling water is sprayed from (front and back) to control the cooling to obtain a target material, and a temperature suitable for winding,
That is, the winding temperature is adjusted and the hot run table is wound on the delivery side. However, in order to accurately perform precise steel strip cooling control on the hot run table, a pipe laminar flow nozzle with a nearly constant cooling capacity and a spray nozzle that can control the cooling capacity are mixedly arranged and both nozzles are used separately for cooling control. Is known to do.

[0003]

The difference in cooling capacity between the pipe laminar flow nozzle and the spray nozzle as described above is as follows.
This is due to the difference in the amount of cooling water sprayed per unit time, and the cooling water supply pipes for both nozzles are separate systems, which complicates the equipment and is disadvantageous in terms of cost. In addition, it is difficult to inject cooling water from the pipe laminar flow nozzle to the spray nozzle when switching the spraying of cooling water to the steel strip, and when switching from the spray nozzle to the pipe laminar flow nozzle, at the same time stopping one nozzle Therefore, when switching, the cooling water is temporarily injected from both nozzles into the steel strip, which may cause supercooling in part of the rolling direction (longitudinal direction) of the steel strip, resulting in material variations. Then, there is a problem that the quality is deteriorated. The device of the present invention has been made in order to advantageously solve such a problem, and a pipe laminar flow nozzle and a spray nozzle are connected and arranged in the same cooling water supply pipe, and the pressure of the cooling water supply to the pipe laminar flow nozzle is arranged. An object of the present invention is to provide a cooling device which is internally provided with a check valve that opens and closes depending on a difference and can instantaneously switch the cooling water supply from a pipe laminar flow nozzle (spray nozzle) to a spray nozzle (pipe laminar flow nozzle). It is a thing.

[0004]

The feature of the device of the present invention resides in that a large number of pipe laminar flow nozzles and spray nozzles are arranged in the cooling water supply pipe in the entire width in the upper width direction of the hot run table, and the pipe laminar flow nozzle is provided. A check valve that closes when high pressure cooling water is supplied and opens when low pressure cooling water is supplied is provided inside, and the spray nozzle can be lowered when high pressure cooling water is supplied and can be raised when low pressure cooling water is supplied. And a cooling device for a hot-rolled steel strip.

[0005]

[Function] The pipe laminar flow nozzle has a substantially constant cooling capacity. Generally, the hot rolling finishes the final rolling stand, passes the plate to the hot run table, and cools the pipe laminar flow nozzle from the pipe laminar flow nozzle. Cooling is performed by switching between cooling by flowing down on the steel strip and cooling by spraying cooling water with a spray nozzle that can control the cooling capacity, and after accurately cooling the steel strip to the target temperature, it is wound into a coil by a winder. It is a thing.

In cooling the hot-rolled steel strip as described above, the pipe laminar flow nozzle has an inverted U-shaped pipe with one end connected in the circumferential direction of the cooling water supply pipe (header) and the other end on the hot run table (steel). The cooling water is supplied at a low pressure of 0.03 to 0.04 kg / cm ² in general because the cooling water is simply allowed to flow down (fall). On the other hand, since the spray nozzle has the function of controlling the cooling capacity, it is generally supplied at a cooling water supply pipe pressure of 1 to 4 kg / cm ^{2 so} that the injection amount of cooling water per unit time can be controlled over a wide range. The steel strip can be accurately cooled to the target temperature by properly using both nozzles.

In the apparatus of the present invention, however, the spray nozzle is configured to be movable up and down, and the pipe laminar flow nozzle is internally provided with a check valve. By supplying low-pressure cooling water from the cooling water supply pipe to both nozzles, the check valve of the pipe laminar flow nozzle is opened, and the cooling water flows down from the pipe laminar flow nozzle onto the hot run table (on the steel strip). By raising the spray nozzle, it moves to a high position where low-pressure cooling water does not flow out of the nozzle, and stops the spraying of cooling water from the spray nozzle onto the hot run table (on the steel strip), and the pipe laminar flow nozzle. The steel strip is cooled by the flow of cooling water from. When stopping the flow of cooling water from the pipe laminar flow nozzle and switching the injection of cooling water from the spray nozzle onto the hot run table (on the steel strip), high-pressure cooling is performed via the cooling water supply pipe (header). When water is supplied, the check valve installed in the pipe laminar flow nozzle operates and becomes a closed state, the flow of cooling water stops and at the same time the cooling water is jetted from the spray nozzle and the spray nozzle descends to drop on the hot run table. The steel strip is cooled by moving it to the cooling water injection position (on the steel strip). In this way, while switching between cooling by the pipe laminar flow nozzle and spray nozzle, the steel strip that passes through the hot run table is accurately cooled to the target temperature (winding temperature) and then wound into a coil on the winder. It is a thing.

As a structure in which the spray nozzle is vertically movable as described above, for example, a flexible nozzle such as a rubber pipe or a resin pipe is attached with the spray nozzle at one end thereof, and the other end thereof is connected to the cooling water supply pipe so as to be flexible. The pipe is provided with a vertically movable sheave or the like, and a spray nozzle attached to one end is configured to be vertically movable by the vertical movement of the sheave. Further, a spray nozzle is attached to one end of a bendable tube so that it can be moved up and down (up and down) as appropriate. Further, the check valve of the pipe laminar flow nozzle as described above is internally provided with a function capable of switching operation depending on the pressure difference between the low pressure cooling water supply and the high pressure cooling water supply.

[0009]

Next, embodiments of the present invention will be described. In FIG. 1, a cooling water supply pipe 2 (header) is arranged in the upper width direction of the hot run table 1, and a large number of pipe laminar flow nozzles 3 are arranged in the cooling water supply pipe 2 over the entire width of the hot run table 1. The pipe laminar flow nozzle 3
A check valve 4 is installed in each of them. A pedestal 8 is provided on the base 5 via an operating rod 7 provided with a fluid pressure cylinder 6 so as to be able to move up and down, and a suspension rod 9 is provided on the pedestal 8 so as to be rotatable over the entire width of the hot run table. A flange 12 in which a sheave 10 and a guide tube 11 are attached to the suspension rod 9.
The spray nozzle 13 is attached to one end of the flexible pipe 14, inserted into the guide pipe 11, and engaged with the sheave 10 to connect the other end to the cooling water supply pipe 2.

Then, low-pressure cooling water (0.03 to 0.04 kg / cm ² ) is supplied from the cooling water supply pipe 2 to the pipe laminar flow nozzle flow nozzle 3, the check valve 4 is opened at a low pressure, and the cooling water is hot run table 1. It is flowed down to the steel strip 15 after the hot finish rolling through which it is passed and cooled. On the other hand, the spray nozzle 13 is operated by operating the fluid pressure cylinder 6 so that
Is raised, the flexible pipe 14 is guided while being guided by the guide pipe 12 while the sheave 10 is rotating, and the low pressure cooling water is stopped from flowing out.

Next, when the flow of the cooling water from the pipe laminar flow nozzle 3 is stopped and the high pressure cooling water (1 to 4 kg / cm ² ) is sprayed from the spray nozzle 13 to the steel strip 15, the switching is performed as shown in FIG. High-pressure cooling water is the cooling water supply pipe 2 as shown in
From pipe laminar flow nozzle 3 and spray nozzle 1
3, the check valve 4 is activated by the water pressure of the high-pressure cooling water that is supplied to the pipe laminar flow nozzle 3 at the same time, and the check valve 4 is closed (blocking operation at 0.1 kg / cm ² or more, 0.1 kg / cm ²
When the temperature is below the limit, it will open and the cooling water will stop flowing out. At the same time, by operating the fluid pressure cylinder 6 to lower the gantry, the spray nozzle 13 attached to the tip of the flexible pipe 14 is lowered while the sheave 10 is rotated,
Move to the cooling water jetting position on the steel strip 15 to transfer the cooling water to the steel strip 1.
Inject to 5 to cool. Further, switching from the spray nozzle 13 to the pipe laminar flow nozzle 3 is operated as described above, and after accurately controlling the coiling temperature of the steel strip in this manner, it is installed on the outlet side of the hot run table 1. The coil is wound around a winding machine (not shown).

Next, an example of a check valve provided inside the pipe laminar flow nozzle will be described. In FIG. 3, when the high pressure cooling water is switched from the cooling water inlet side 16 of the pipe laminar flow nozzle nozzle 3 into the high pressure cooling water, the elasticity of the spring 17 is overcome and the spring 17 is extended to press the valve body 18 against the flow passage 19. Block and stop the outflow of cooling water. Further, when the low pressure cooling water is switched and press-fitted, the spring 17 overcomes the inflow pressure of the cooling water and contracts as shown in FIG.
8 is separated from the flow path 19 to open the flow path 19 and allow the cooling water to flow out. Therefore, the check valve 4 is switched by arranging the spring 17 which can be switched by the switching pressure difference.

[0013]

As described above, the pipe laminar flow nozzle (spray nozzle) and the spray nozzle (pipe laminar flow nozzle) can be switched instantly, and the cooling control of the steel strip can be precisely performed, so that the variation of the material can be prevented. The quality can be improved. Further, the winding temperature of the steel strip can be accurately controlled, and the yield reduction due to defective winding of the steel strip can be prevented. Further, the same amount of cooling water as the cooling water for supplying the cooling water to the pipe laminar flow nozzle and the spray nozzle can be supplied by the same cooling water supply pipe, which is advantageous in terms of equipment.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the device of the present invention.

FIG. 2 is a perspective view showing an embodiment of the device of the present invention.

FIG. 3 is a vertical sectional view of a check valve.

FIG. 4 is a vertical sectional view of a check valve.

[Explanation of symbols]

 1 Hot run table 2 Cooling water supply pipe 3 Pipe laminar flow nozzle 4 Check valve 13 Spray nozzle

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C21D 9/573 101 Z

Claims (1)

[Claims] 1. A large number of pipe laminar flow nozzles and spray nozzles are provided in a cooling water supply pipe over the entire width of the hot run table in the width direction, and the pipe laminar flow nozzle is closed when high pressure cooling water is supplied and when low pressure cooling water is supplied. A cooling device for a hot-rolled steel strip, wherein a check valve for opening is internally provided, and the spray nozzle can be lowered when high pressure cooling water is supplied, and can be raised when low pressure cooling water is supplied.