JPH0564686B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for online cooling of hot-rolled high-temperature steel sheets.

(Prior Art) For the purpose of improving the mechanical properties of hot-rolled high-temperature steel sheets and reducing the amount of alloying elements, many heat treatment methods and devices have already been proposed for cooling the steel sheets online to a predetermined temperature. has been developed and put into practical use.

That is, FIG. 6 shows the general configuration of an apparatus for carrying out this type of method, in which slit laminar nozzles 1 arranged at required intervals are used to cool the upper surface of the steel plate A, and conveyor rollers are used to cool the lower surface. A spray nozzle 3 arranged between the two is used. By the way, the method using the slit laminar nozzle 1 can form a plate-shaped water film collision surface on the steel sheet A in the sheet width direction, so it is a method with excellent cooling uniformity in the sheet width direction. The laminar style is
After colliding with a high-temperature steel plate, as shown in Fig. 7, water flows on the steel plate surface into upstream and downstream sides with respect to the sheet threading direction, from a so-called water film collision surface area a to a flowing water area b.
The two flowing waters collide near the center, and an interference band c is formed here. The behavior of water in this interference band c is generally not perpendicular to the direction of sheet passing, but tends to be inclined or has a mountain-like shape extending downstream.
A part of the water reaches the water film collision surface area a from the flowing water area b on the downstream side, which causes a decrease in cooling capacity and uneven cooling in the board width direction. As measures to solve such problems, Japanese Patent Application Laid-Open No. 59-202113, Japanese Patent Application Laid-Open No. 61-12829, and even Japanese Patent Application Laid-open No. 59-
There is a technique disclosed in Publication No. 123724.

(Problems to be Solved by the Invention) The above-mentioned Japanese Unexamined Patent Publication No. 59-202113 discloses a method and a device for tilting one cooling water flow in a direction away from the other cooling water flow. , JP-A No. 61-12829 discloses that the nozzle is arranged so that the cooling water discharge direction is at an angle to the upstream side with respect to the sheet passing direction, so that a large amount of the discharged cooling water flows to the upstream side. A method is shown. In other words, these are all proposals to prevent the cooling capacity directly below the nozzle from decreasing by tilting the nozzle with respect to the sheet threading direction to form an interference zone in the center, but in order to implement these methods, It is undeniable that as equipment becomes larger, operations become more complex.
Not practical. Furthermore, the amount of water increases from the center of the interference band to the ends of the steel plate, which causes the ends to be supercooled. As a countermeasure to this, consideration must be given to adjusting the water volume distribution by changing the gap of the slit nozzle in the width direction of the plate.

Furthermore, JP-A-59-123724 discloses a method in which hairpin-type nozzles are arranged near the center in the width direction of the plate between slit-type nozzles as a means for adjusting cooling unevenness in the width direction of the plate. In either case, the equipment structure becomes complicated, and there are problems such as the inability to form a smooth flowing water layer on the steel plate.

The present invention was made in order to solve such problems, and it eliminates the interference zone of the water flow on the plate that causes a decrease in cooling performance in the water film collision surface area, and also uses special technology for the slit laminar nozzle. It is an object of the present invention to provide a cooling method that can achieve uniform cooling in the width direction of a plate without adding any devices.

(Means for Solving the Problems) A method for cooling the top surface of a high-temperature steel plate according to the present invention cools the top surface of a steel plate using cooling water discharged from multiple rows of slit laminar nozzles arranged substantially perpendicular to the threading direction. A cooling method in which an auxiliary nozzle is arranged between the slit laminar nozzles and extends across the entire width of the plate, and the discharge flow is directed directly below the auxiliary nozzle and has a flow direction different from the width direction of the plate. It is characterized by forming a layer.

(Function) In the present invention, an auxiliary nozzle is arranged between multiple rows of slit laminar nozzles, extending toward the sheet passing direction and spanning the entire width of the steel plate, and cooling water is discharged from the auxiliary nozzle.
This suppresses the occurrence of an interference zone of the water flow on the plate, and also forms a drainage flow layer whose flow direction is different from the width direction of the plate, thereby achieving uniform cooling over the entire surface of the steel plate.

(Example) An example of the present invention will be described below based on FIGS. 1 to 5. In FIGS. 1 and 2, the slit laminar nozzle 1, conveyance roller 2, and spray nozzle 3 are the same as those shown in FIG. 6.

By the way, in FIGS. 1 and 2, reference numeral 4 indicates auxiliary nozzles arranged between the slit laminar nozzles 1, and these auxiliary nozzles 4 are arranged at a predetermined angle with respect to the sheet passing direction. It has a length spanning the entire width of the steel plate A to be cooled.

The hot-rolled steel plate A to be cooled is transferred to the conveyor roller 2
The cooling water is sent in the direction of the arrow by the cooling water discharged from the slit laminar nozzle 1 and the auxiliary nozzle 4 disposed on the upper surface, and the spray nozzle 3 disposed on the lower surface, until the temperature reaches a predetermined temperature. while cooling. In this case, the cooling water film that is discharged from the slit laminar nozzle 1, which is arranged substantially perpendicular to the sheet passing direction, and is divided into upstream and downstream sides in the sheet passing direction on the surface of the steel sheet A, is discharged from the auxiliary nozzle 4. The water is dammed up by a water film that flows in the width direction of the plate, and a hydraulic action is added to the flow in the width direction of the plate, thereby forming a discharge flow layer e whose flow direction is different from the width direction of the plate, as shown in Fig. 3. It turns out. This means that the cooling water film from the slit laminar nozzle 1, which is blocked by the water film discharged from the auxiliary nozzle 4, flows from nearer to the falling point of the cooling water film from the slit laminar nozzle 1. It is from. In other words, the discharge flow layers e with different flow directions suppress the occurrence of the interference band caused by the water film collision described above, and furthermore, as shown in Fig. 4, the sheet is cooled with the same amount of water across the width direction. Ru. Note that it is preferable to use a slit laminar nozzle as the auxiliary nozzle 4, and the desired effect can be achieved if the angle θ oblique to the sheet passing direction is 10° or more.

By the way, using the equipment shown in Figures 1 and 2 above, the thickness of the plate is 25 mm, the width of the plate is 3000 mm, and the length is 16000 mm.
When a high-temperature steel plate of
I was able to keep it within.

(Effects of the Invention) As explained above, the present invention arranges a large number of rows of slit laminar nozzles substantially perpendicular to the passing direction of a hot-rolled high-temperature steel sheet, and also arranges a plurality of slit laminar nozzles between the slit laminar nozzles. An auxiliary nozzle that discharges cooling water across the entire width of the plate is arranged in the direction of the plate passing direction, and a discharge flow layer is formed in the vicinity immediately below the nozzle with a flow direction different from the width direction of the plate. Therefore, it is possible to eliminate the interference zone of the water flow on the plate that causes a decrease in the cooling ability of the water film collision surface, and special technical measures such as changing the gap of the slit laminar nozzle along the width direction of the plate can be applied. Uniform cooling can be achieved over the entire surface of the steel plate.

[Brief explanation of drawings]

FIG. 1 is a plan view of an apparatus showing an embodiment of the present invention, FIG. 2 is a side view thereof, FIG. 3 is a schematic diagram showing the behavior of a steel plate water flow according to the present invention, and FIG. 4 is a discharge flow according to the present invention. Figure 5 showing the amount of water passing through the plate width direction.
The figure is a comparison diagram of the stopping temperature distribution in the board width direction between the method of the present invention and the conventional method, FIG. 6 is a side view of an apparatus implementing the conventional method, and FIG. 7 is a diagram of the flow pattern of water flow on the board according to the conventional method. FIG. 8 is a schematic diagram showing the behavior of water flow on a plate according to the conventional method. 1 is a slit laminar nozzle, 2 is a conveyance roller, 3 is a spray nozzle, and 4 is an auxiliary nozzle.

Claims (1)

[Claims] 1. In a method for online cooling of a hot-rolled high-temperature steel plate, multiple rows of slit laminar nozzles are arranged substantially perpendicular to the threading direction of the high-temperature steel plate, and the threading is carried out between these slit laminar nozzles. It is characterized by arranging an auxiliary nozzle that is oblique to the direction and discharges cooling water across the entire width of the plate, and forming a discharge flow layer with a flow direction different from the width direction of the plate in the vicinity of the auxiliary nozzle. A method for cooling the top surface of high-temperature steel plates.