JPS63101017A - Cooling device for hot steel sheet - Google Patents

Abstract

PURPOSE:To increase the cooling capacity and to uniformize the cooling by installing a dewatering roll facing to a lower roll above a steel sheet, jet nozzles in the front and the behind of the lower roll, and guide covers and side covers between the nozzles and both rolls. CONSTITUTION:A high pressure cooling water jetted onto a steel sheet 5 is guided by guide plates 8 and cools the sheet 5 in both the carrying and reverse directions. Jet nozzles 6 are installed in front and behind of a dewatering roll 7 and a lower roll so that their jetting directions are opposite to each other. The jetted cooling water overflows from an opening 10 so that it falls and is discharged through the guide cover 8 in the upper surface side and falls through nothing in the lower surface side. Therefore, influences by residual cooling water in both the upstream and downstream of a carrying roll 2 and the dewatering roll 7 are eliminated. Installation of side covers 9 eliminates cooling water flow in the width direction. The large cooling capacity and uniform cooling in the width direction for the steel sheet are offered by this device.

Description

[Detailed description of the invention] "Industrial application field" The present invention provides on-line controlled cooling after rolling of thick plates.

The present invention relates to a cooling device for high-temperature steel sheets used for cooling hot steel sheets in direct quenching processes or reheating heat treatment processes, and for cooling other hot steel sheets and hot steel strips.

"Prior Art" In recent years, in hot plate rolling equipment, a technique for cooling a rolled plate on-line is being developed for the purpose of producing a plate with high strength and high toughness.

When cooling a hot steel plate, a cooling device is required to cool the plate uniformly in the width direction and symmetrically in the vertical direction of the plate at a required cooling rate.

Initially, the heated steel plate is cooled by water at the exit side of the rolling mill 1, as shown in FIG. 6, with the laminar flow nozzle 3 from above and the spray nozzle 4 from the bottom while the steel plate 5 is running on conveyor rollers 2. This method was common.

However, the method shown in the figure has the following problems and cannot meet the above requirements.

i) Although the cooling water supplied from the laminar flow nozzle 3 remains on the steel plate 5 as stagnant water, the cooling water power falling from the laminar flow nozzle <? Because it is blocked by stagnant water,
Cooling capacity is low.

ii) Since the water accumulated on the steel plate ultimately flows to both ends in the direction of the plate, the water density at both ends becomes greater than that at the center of the plate, and both ends are supercooled.

1ii) In the lower part of the steel tt, the cooling water jetted upward falls immediately after colliding with the steel plate, so the cooling area is narrower than in the upper part where there is accumulated water, and as a result, the cooling capacity is lower than that in the upper part. low.

iv) Furthermore, since there is a conveyance roller in the lower part, the cooling area tends to be narrow<1ii).

V) The cooling methods for the upper and lower parts are different in the first place, and 1i
Due to the problems i) and iy), the steel plate cannot be cooled symmetrically from above and below.

As a solution to the above drawbacks, Japanese Patent Application Laid-Open No. 58-869
As shown in Figures 3 and 4, Publication No. 22 discloses a rapid cooling device for steel plates (Figure 3) in which a draining roller is disposed just before the point of impact of slit laminar cooling water on the heated steel plate; Furthermore, a device has been proposed in which slit-shaped cooling water is brought close to the heated steel plate and sprayed at high pressure, and a guide plate parallel to the upper and lower surfaces of the heated steel plate is arranged between the nozzle and the draining roller (Fig. 4). has been done.

It is said that this eliminates the above-mentioned drawbacks mainly caused by the projected cooling water remaining on the hot steel plate that is being fed one shell.

[Problems to be Solved by the Invention] However, in the cooling device shown in FIGS. 3 and 4, in FIG. After colliding with the draining roller, the cooling water flows in the width direction, which has the disadvantage of uneven cooling in the width direction.Also, the parts outside the edge of the steel plate where there is no steel plate are An opening corresponding to the thickness of the steel plate is formed, and the cooling water flows out from the opening, which promotes the flow of the cooling water in the width direction, resulting in the problem that the edge portion of the steel plate is overcooled.

In addition, in Fig. 4, the cooling water that collides with the draining roller overflows onto the upper surface of the guide plate, so although the flow in the middle direction is improved in the center view of the steel plate, a flow in the width direction still occurs at the edge part, and In the openings outside both edge portions of the steel plate where there is no steel plate, there is a problem in that the edge portions of the steel plate are overcooled because cooling water still flows out.

``Means for solving problems'' and ``effects'' The present invention was made in view of the circumstances surrounding ridges, and its gist is that a high-temperature steel plate is run on a conveying roller, and cooling water is applied to the upper and lower surfaces. In a device that cools by spraying water, a draining roller is placed on the top of the steel plate at a position facing the lower roller,
Jet nozzles whose jetting directions toward the steel plate surface face each other are provided before and after the draining roller and the lower roller, and a guide having an opening near the upper and lower rollers parallel to the steel plate surface between the nozzle, the draining roller, and the lower roller. The above-mentioned problems are solved by providing a cover and a guide plate that covers both ends of the guide cover and the roller.

"Example" This will be explained in detail below based on the drawings.

That is, the cooling device for high temperature steel plate according to the present invention is shown in FIG.
To explain using FIG. 2, the steel plate 5 is conveyed by the conveyance roller 2 in the direction of arrow (A). The slit jet-shaped cooling water supply nozzle and the header 6 are arranged facing each other along the conveying direction and the vertical direction of the steel plate 5 at an appropriate distance, and the lower conveying roller A draining roller 7 is disposed at the upper part opposite to 2. Furthermore, a guide cover 8 parallel to the upper and lower surfaces of the steel plate 5 passing on the feed line is provided between the slit-shaped nozzle 6, the draining roller 7, and the conveying roller 2, and a side plate is provided along the edges of the guide cover 8 and the draining roller rough. 9 is placed.

In this cooling device, the high-pressure cooling water injected onto the steel plate 5 is guided by the guide plate 8 and flows in the transport direction and the opposite direction while cooling the steel plate 5, as shown by the arrow, and the cooling water collides with the draining roller. Water overflows from the opening 10 between the guide cover 8 and the draining roller, flows in the width direction on the upper surface of the upper guide cover on the upper surface, falls and is discharged from both ends, and is directly discharged from the opening 10 on the lower surface. Furthermore, in the areas outside both ends of the steel plate where there is no steel plate, openings are created just by the thickness of the steel plate, but since the slit jet nozzles 6 are installed so that the cooling water injection directions are opposite to each other, When the cooling water sprayed in the conveying direction and the opposite direction collides between the conveyance roller 2 and the draining roller ruff, residual cooling water affects the conveying roller 2 and the draining roller both upstream and downstream. This is prevented.

Furthermore, since the side plates 9 are arranged along the edges of the guide cover 8, the conveying roller 2, and the draining roller, the widthwise flow of the cooling water that collides between the conveying roller 2 and the draining roller is regulated. Since the cooling water overflows from the opening 10 between the guide cover 8 and the draining roller, no widthwise flow of cooling water for cooling the steel plate 5 occurs after all.

Therefore, by cooling the steel plate using the above-mentioned cooling device, it is possible to cool the steel plate symmetrically from above and below and uniformly in the width direction of the plate with a large cooling capacity.

Note that although a slit-shaped jet nozzle is used in the present invention, the present invention is not limited to this; any jet nozzle may be used; for example, a drill-hole jet nozzle may also be used to achieve the object of the present invention.

Next, the results of implementing the present invention will be described.

In the conventional cooling device shown in FIG. 4 and the cooling device according to the present invention shown in FIGS. 1 and 2, the plate thickness is 25+sm and the plate width is 30.
001m thick steel plate after hot rolling from 800℃ to 500℃
cooled down to.

The temperature distribution in the width direction of the thick steel plate after cooling at this time is shown in FIG. 5 for the conventional method (a) and the present invention (b).

As shown in FIG. 5(a), in the case of the conventional method, flow in the middle direction occurs at both ends of the plate, so that the plate is supercooled by about 50° C. compared to the center. On the other hand, as shown in the same figure (b),
In the case of the present invention, since almost no flow occurs in the width direction,
The temperature drop at both ends of the plate is reduced to approximately 5℃ compared to the center.
Conventional shortcomings have been greatly improved.

"Effects of the Invention" As described above, by using the high-temperature steel plate cooling device according to the present invention, (1) symmetrical cooling can be achieved with a large cooling capacity in the vertical direction of the steel plate.

(2) Cooling water does not flow in the width direction, but only in the conveyance direction of the steel plate and the opposite direction, so uniform cooling can be achieved in the width direction of the steel plate.

[Brief explanation of the drawing]

1 and 2 are front explanatory views and plan explanatory views of the device of the present invention,
3 and 4 are explanatory diagrams of the conventional means, FIG. 5 is an explanatory diagram of the temperature distribution of the steel plate in the device of the present invention and the cooling device shown in FIG. 4, and FIG. 6 is an explanatory diagram of the original cooling method. FIG. DESCRIPTION OF SYMBOLS 1... Rolling machine, 2... Conveyance roller, 3... Laminar flow nozzle, 4... Spray nozzle, 5
...Steel plate, 6...Slit jet nozzle, 7
...Draining roller, 8...Guide cover,
9... Side plate, 10... Opening. Zuiro 4 Mushiki Uragi (a) (b) 1 color Ωㅅ

Claims (1)

[Claims] In a device that runs a high-temperature steel plate on a conveyance roller and cools it by spraying cooling water on the top and bottom surfaces, a drain roller is disposed on the top of the steel plate at a position facing the lower roller, and a drain roller is installed before and after the drain roller and the lower roller. A guide cover having openings parallel to the steel plate surface near the upper and lower rollers between the nozzle, the draining roller, and the lower roller, and both ends of the guide cover and the roller. 1. A cooling device for high-temperature steel sheets, characterized in that a guide plate is provided to cover the entire surface of the steel plate.