JPS60213308A - Cooling device of hot rolled steel sheet - Google Patents

Abstract

PURPOSE:To prevent the collision between the inside end of each shielding plate and falling cooling-water by specifying the arrangement of nozzles and the shape of the shielding plate in a title device provided with the shielding plates, capable of freely advancing and retreating and located at both sides of the passing direction of a steel sheet between the steel sheet and the nozzles of the former of upper and lower cooling-water headers. CONSTITUTION:The upper surface of a hot rolled steel sheet 12 on a table 10 is cooled by the cooling water falling from the nozzles 15 of upper cooling headers 11, which are parallelly arranged at prescribed intervals in the sheet passing direction above the cooling table 10 placed at the outlet side of a hot rolling mill. Here, for instance, headers 14 of (a)-(d) are arranged parallelly in sequence in the sheet passing direction, and the exits of nozzles 15 are zigzag arranged at intervals with respect to respective directions of the width and length of the sheet, and the arranging patterns of nozzles 15 are divided in the sheet-length direction into plural zones. Further, a partial inside edge 20 provided with a back and forth displacement-difference in the moving direction of the sheet is formed at each inside-end edge of shielding plate 18 in accordance with the nozzle pattern in this zone.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cooling device for hot-rolled steel sheets, and more specifically, the present invention relates to a cooling device for hot-rolled steel sheets, and more specifically, the present invention relates to a cooling device for hot-rolled steel sheets. The present invention relates to an apparatus for cooling inter-rolled steel plates on-line.

(Prior art) Conventionally, on-line cooling has been used to make steel tougher by rapidly cooling or quenching, which effectively utilizes the heat retained in the steel during rolling. Japanese Patent Publication No. 53-37809 (Conventional Example 1) and Japanese Utility Model Application Laid-Open No. 58-47311 (Conventional Example 2) have been proposed because they are advantageous because they can be produced in a short period of time.

That is, as shown in FIGS. 8 and 9, in conventional example 1, a roll 1 of a hot rolling mill is followed by a rapid cooling zone by a laminar flow, followed by a slow cooling zone by a shower having a length tz. The upper surface of the steel plate on pass line 2 is treated with laminar flow nozzle group 3, and the upper surface is treated with spray nozzle group 4.
The bottom surface of each device is cooled on-line.

In this conventional example 1, as shown in FIG. 9, the nozzles of the laminar nozzle group 3 are arranged at approximately equal intervals in the direction of the board and in the direction of the board's longitudinal direction, and at arbitrary stages when viewed in the board's longitudinal direction. The nozzle array in the direction of the middle plate and the nozzle array in the direction of the next plate are arranged in a staggered manner, shifted by approximately half a pitch.

However, in the nozzle array of Conventional Example 1, when viewed in the direction of threading the steel plate, the nozzle array aligned in the direction of the steel plate appears to have a very small pinch, making it difficult to ensure uniform cooling. In extreme cases, it is also possible to make them continuous.

As shown in FIGS. 10 and 11, in conventional example 2, when cooling the steel plate 6 on the roller type cooling table 5 by the laminar flow nozzle group 3, both sides of the intermediate position between the table 5 and the nozzle group 3 are used. The shielding plate 7 that cants the cooling water from the nozzle group 3 is made to be able to move forward and backward in a direction perpendicular to the steel plate transfer direction A by means of a cylinder device 8, etc., so that even if the width B of the steel plate 6 is large or small, the amount of movement x Cooling water can be cut.

(Problems to be Solved by the Invention) However, in Conventional Example 1, due to the presence of cooling water flowing along the upper surface of the steel plate at both ends of the steel plate, overcooling may occur, causing warpage, bending, etc. Moreover, since there are steel plates of various sizes, the above-mentioned disadvantage becomes more noticeable.

In addition, in Conventional Example 2, since the inner end shape of the shielding plate 7 is an IT line shape parallel to the steel plate transfer direction A as shown in FIG. Water may collide and scatter, and even though uniform cooling in the RP direction of the steel plate is attempted as shown in Fig. 12, supercooled areas may occur due to collisions and scattering as shown in Fig. 13. .

In particular, when the nozzle arrangement is arranged in a staggered manner to achieve uniform cooling, the above-mentioned possibility of IH collision becomes extremely high.
If a collision actually occurs, the cooling situation shown in FIG. 13 will occur.

(Means for Solving the Problem) The present invention provides uniform cooling performance by the nozzles of the upper cooling water header arranged in a staggered manner on the cooling table provided on the exit side of the hot rolling mill, while also providing a shielding plate. Collision between the edge of the hot rolling mill and the cooling water is avoided, and in order to achieve this purpose, in the present invention, cooling water headers are provided above and below the cooling table provided on the outlet side of the hot rolling mill. The shielding plates are located between the staggered nozzles of the upper cooling water header and the steel plate on the cooling table, and are movable forward and backward in the direction perpendicular to the steel plate transfer direction. In the equipped hot-rolled steel plate cooling device, the nozzles of the upper cooling water header are arranged at intervals in each direction of the plate inside direction and the plate longitudinal direction, and the arrangement pattern of the nozzles is arranged in the plate longitudinal direction. The shielding plate is divided into a plurality of parts in the direction, and has a shielding plate in which front and rear transfer portions are formed at each inner edge of the shielding plate in accordance with the nozzle pattern in each divided zone in the moving direction of the shielding plate. It is characterized by this.

(Function) In the present invention, when a horizontal plate coming out of a hot rolling mill is placed on a cooling water table, its upper surface is heated by the cooling water from the nozzle group of the upper cooling water header arranged in a staggered manner, and its lower surface is heated by the lower surface. The cooling water from the nozzle group of the cooling water header cools each on-line, and by setting the amount of advance and retreat of the shield plate depending on the inside of the steel plate, the cooling water cut by the shield plate is achieved. At the same time, collision between each inner end of the shield plate and the flowing cooling water is avoided.

(Example) Referring to FIG. 1, a cooling table 10 is provided on the exit side of the hot rolling mill, and the table 10 is composed of a group of rollers 11 arranged in parallel at intervals in the sheet passing direction. It consists of:

The hot-rolled steel plates 12 coming out of the hot-rolling mill are sequentially conveyed onto the cooling table 10 in a direction perpendicular to the drawing.

Above the cooling table 10, a flexible pipe 1 is connected to the main cooling water supply pipe.
The upper cooling water headers 14 are connected to each other through the upper cooling water headers 14 and the upper cooling water headers 14 are arranged in parallel at predetermined intervals in the sheet passing direction.

A cooling water nozzle 5 is provided on the upper cooling water rudder 14, and the upper surface of the hot rolled steel plate 12 on the cooling table IO is cooled by the cooling water flowing down from the nozzle 15 (laminar flow). has been done.

The outlets of the nozzles 15 of the cooling water header 14 are arranged in a staggered manner at intervals in the direction of the plate and in the longitudinal direction of the plate. It is divided into multiple parts in different directions.

That is, in each of the embodiments shown in FIGS. 2 to 4,
An arrangement pattern is shown in which nozzles 15 of four types of cooling water headers 14, a, b, c, and d, are sequentially arranged in parallel in the longitudinal direction of the plate.

The header 14 of a has row groups in which nozzles 15 are arranged at predetermined pinch L intervals in the header longitudinal direction (direction perpendicular to the sheet passing direction) at a pitch Ll (LI may be equal to L) in the sheet passing direction. It is composed of nozzles 15 arranged at a distance of L/2 in the direction of the plate.

The header 14 of b is the header 14 of a mentioned above and the nozzle 15.
It is composed of a group of rows with the same pitch,
The pitch is Lz (which may be equal to Lz beam) in the sheet threading direction with respect to a, and any nozzle 15 of a in the sheet direction is on a plane passing through the sheet center line X. When, the nozzle 15 of the header 14 of b is L/4 from the center line
are arranged at position L3.

The headers 14 in C and d have the same pinch pitch as the nozzle 15 in the header 14 in A, but they are located at the smallest pitch on the center line One of the nozzles d is positioned with the center line X as a boundary.

By arranging the headers a to d in this arrangement sequentially in the sheet passing direction, the nozzles 15 of the upper cooling water header 14 have their outlets arranged in the sheet inside direction and in the sheet longitudinal direction (sheet passing direction). The nozzles 15 are arranged in a staggered manner at intervals in each direction, and the arrangement pattern of the nozzles 15 is divided (divided) into a plurality of zones in the longitudinal direction of the plate. is ensured.

Furthermore, a lower cooling water header 16 is provided between the rollers 11 on the lower side of the cooling table 10.
Cooling water can be ejected from the nozzle 17 onto the lower surface of the steel plate 12, for example, in a radial and diffused manner.

Here, the hot rolled steel plate 12 on the cooling table 10 is connected to the nozzle 15 of the upper cooling water header 14 and the lower cooling water header 1.
On-line controlled cooling and quenching are performed using the cooling water from the nozzle 17 of No. 6.

Shielding plates 18 are provided on both sides of the intermediate position between the upper surface of the steel plate 12 on the cooling table 10 and the nozzle 15 of the upper cooling header 14, and are movable forward and backward in a direction perpendicular to the steel plate transfer direction (threading direction). In this embodiment, each of the shielding plates 18 is movable forward and backward by a telescopic cylinder mechanism 19.

Conventionally, each inner edge of the shielding plate 18 was parallel to the sheet passing direction, but in the present invention, the shielding plate 18 has a shielding plate according to the nozzle pattern in the zone divided in the sheet passing direction. A partial inner edge 20 is formed on each inner edge of the plate 18 to provide a front and rear transport difference in the direction of movement of the cough plate.

Various patterns can be used to form the inner end 1!20 of the portion of the shielding plate 18 with a difference in front and rear transport, but the basic pattern will be explained with reference to FIG.

In Fig. 2, the nozzle 15 in the header a is located on the center line A difference in transport is established.

That is, the six shielding plates 18 A and B shown in FIG. 2 are examples in which there are steps to provide a transfer difference in the transfer direction Y, and the headers a and b and headers C and d are treated as one set. It is considered to be a shielding board.

Now, with the position P of the shielding plate 18 corresponding to the front position of the header a having the nozzle 15 on the center line X as a reference, position P is the nozzle By determining whether or not the nozzle is located directly below, the nozzle pinch L can be set with sufficient margin at other nozzle arrangement positions.

In addition, in FIG. 3, the shapes of the inner ends of the shielding plate 18 in A are PQR3 (however, from P to Q is a straight line parallel to X, QR is a step, and from R to S is a straight line parallel to X), B shielding plate 18
The shape of each inner end of is TUVII (however, TRI is a straight line parallel to X, t+V is a step, and C is a straight line parallel to X), and the staggered arrangement pattern is the minimum pitch Lm when viewed from the steel plate transfer direction. Transport difference, that is, step QR and UV
In the case of n-Lm (an example where n=2), the range in which the nozzle and the shielding plate 18 are prevented from overlapping is in the moving direction Y, and the nozzle position is from [ to Ll, that is, (L/2-d-2
y ) [where d is the nozzle diameter and y is the thickness of the shield plate end. ], whereas A and B of the shielding plate 18
If the transfer difference αR° or UV" is different from nLIll, the widest range to avoid overlapping the nozzle and shielding plate is (L/2- d-2y-R'R), which allows control at narrow intervals. This poses a problem, including the requirements for nozzle construction, etc.

The example in Fig. 2 shows that the header 14 of a" d is made bare, and the shielding plates 18 A and B are arranged alternately. 'of,
^, B, A'S B' are shown, and when these two examples are compared, the movement reference Fi of the shielding plate 18 is
According to the movement of l, the nozzle cut (
cooling water cut).

That is, by arranging the shielding plates 18 in the order of ^, B, A'', and B' as in this embodiment, more detailed temporary shielding settings (control) are possible, and this is possible during cooling as shown in FIG. This means that it is possible to more accurately set the optimum value for preventing the edges of the steel plate from being properly cooled to prevent the steel plate from deforming.

Note that FIG. 6 shows the arrangement pattern of the shielding plates 18.

(Effect of the invention) When hot-rolled steel plates are cooled on-line from above and below on a cooling table, the nozzles of the upper cooling water header are arranged in a staggered manner with intervals in both the width direction and longitudinal direction of the plate. Because of the arrangement, uniform cooling can be ensured.

In addition, when ensuring uniform cooling, excess cooling water is forced down at both ends in the board direction, and cooling water must be cut when the board width changes. At this time, if a shielding plate is provided as a masking material, there is a risk that the cold water will splash onto the edge of the shielding plate (i), but in the present invention, the shielding plate has different transfer portions in the front and rear directions. Since it is formed at the inner end, collision with the cooling water flowing down from the upper nozzle is avoided, thereby ensuring uniform cooling throughout the entire board.

In the example, the transfer difference is formed as a straight line, but what is actually effective for cutting cooling water is the transfer difference of the shield plate corresponding to the nozzle position, and this is a straight line or a line diagonal to X. The shape may be a curved line.

[Brief explanation of drawings]

Fig. 1 is a front sectional view showing an embodiment of the present invention, Fig. 2 is a conceptual diagram showing the relationship between a nozzle pattern and a shielding plate, and shows the first embodiment, and Fig. 3 similarly shows a second embodiment. , FIG. 4 similarly shows the third embodiment, FIG. 5 is a diagram showing the relationship between the pass line and the number of nozzle cuts, FIG. 6 is a plan view of the overall configuration of the shielding plate arrangement, and FIG. Comparison graph between the conventional example and the embodiment of the present invention, Fig. 8 is an overall explanatory diagram of the conventional example 1, Fig. 9 is a plan view of the same nozzle vacuum, Fig. 10 is a front sectional view of the conventional example, and Fig. 11 is the same. The plan view, FIGS. 12 and 13 are graphs showing the cooling temperature distribution in the direction of the steel. 10--Cooling table, 14-Upper cooling water header, 1
5-・14 nozzle, 16-lower cooling water header, 17・
...16 nozzles, 18-shielding plate, 20-transfer differential part. No. 712 @Figure 6? I working chord

Claims (1)

[Claims] 1. On the cooling table used on the exit side of the hot rolling mill,
A cooling water header is provided at the bottom, and a shield plate is located between the staggered nozzles of the upper cooling water header and the steel plate on the cooling table, and can move forward and backward in a direction perpendicular to the steel plate transfer direction. In a cooling device for hot-rolled steel sheets provided on both sides along the sheet, the nozzles of the upper cooling water header are arranged at intervals in each direction of the inside of the sheet and the longitudinal direction of the sheet,
The arrangement pattern of the nozzles is divided into a plurality of sections in the longitudinal direction of the plate, and according to the nozzle pattern in each divided zone, a front and rear transfer portion is provided at each inner edge of the shielding plate in the direction of movement of the linear velocity shielding plate. 1. A cooling device for a hot-rolled mesh board, characterized by having a shielding plate formed with. 2. Claims characterized in that, when the minimum pitch of the nozzles of the upper cooling water header viewed from the steel plate transfer direction is llpm, the step for creating a transfer difference is formed as an integral multiple of zp. 2. The cooling device for hot-rolled steel sheets according to item 1.