JPH09141320A - Nozzle type upper surface cooling header pipe for cooling steel strip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly cool a steel strip over its whole width by uniforming the flow rate distribution of a cooling water flowing out of respective nozzles of a nozzle type upper surface cooling header pipe in a hot rolling steel strip cooling device. SOLUTION: A current plate 2 parting its cross section into a cross shape in the longitudinal direction is provided in the pipe body of the header pipe 1 wherein many nozzles 4 are attached to the upper part with the outlet faced downward. An intercepting plate 3 intercepting the upper half part of the pipe body parted with the current plate 2 is attached to one end side of the header pipe 1 so as to form a gap between the inner surface of the tube body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle type top cooling header pipe for cooling steel strip installed in a hot continuous rolling mill.

[0002]

2. Description of the Related Art Generally, in hot continuous rolling equipment,
A billet having a thickness of 200 to 350 mm is heated to about 1250 ° C in a heating furnace, and the billet is heated to about 1.2 to 25.4 by a hot rolling mill including a rough rolling mill group and a finishing rolling mill group. Roll to a steel strip with a thickness of mm. The steel strip rolled in this way is cooled by the coiler to approximately 900 by the cooling water jetted from the cooling nozzle of the cooling device provided in the table roller between the finishing mill group and the coiler. Cool from a temperature of ℃ to a specified temperature of 700 to 500 ℃.

For the above-mentioned cooling, the cooling device, which extends from the group of finishing rolling mills to the coiler to approximately 2/3 of the length of the table rollers of about 100 m or more, is divided into several tens of control units. The flow rate and the discharge timing of the cooling water are controlled in consideration of the cooling rate, the heat transfer coefficient, etc. based on the temperature and speed of the steel strip to be processed.

A nozzle type upper surface cooling header for forming a laminar flow is known as one of means for cooling the upper surface of the steel strip in the above cooling device.

FIG. 6 is an explanatory view showing the types of nozzle type upper surface cooling header pipes. As shown in FIG. 6, the nozzle type upper surface cooling header pipes have different flow distributions A,
There are four types, B, C and D.

As shown in FIG. 6, the type A has a structure in which a water supply pipe is attached to the central portion of the nozzle header pipe, and the flow rate of the cooling water is highest in the central portion of the nozzle header pipe, and then left and right thereof. A distribution with many ends is shown. Type B
Shows a structure in which a water supply pipe is attached to one end of the nozzle header pipe, and the flow rate of cooling water is distributed at the end on the water supply side of the nozzle header pipe and at the end thereof.

The type C has a double-walled nozzle header pipe, in which cooling water is supplied from one end of the header pipe into the inner pipe and is discharged from the one end of the header pipe through the outer pipe. Yes, the flow rate of the cooling water has a mountain-shaped distribution in which the central portion of the header pipe is large and the both end portions are small. Type D also has a structure in which the nozzle header pipe is a double pipe type and a partition wall is provided in the center of the outer pipe, and the flow rate of the cooling water has a sloped distribution on the inlet side of the nozzle header pipe and a mountain-shaped distribution on the outlet side. Shows.

[0008]

As shown in FIG. 6, in the conventional nozzle type upper surface cooling header pipes, in any of types A to D, the flow rate distribution of the cooling water is not uniform due to the dynamic pressure and the static pressure action. On the other hand, in the case of the type B in which nothing is installed in the header pipe, the dynamic pressure remarkably acts and a gradient distribution is formed.
In the case of the type C double-pipe upper cooling header pipe, the gradient distribution like that of the type B is eliminated, but the mountain side distribution has many central parts and few end parts, and due to the diameter of the double pipe, Since the pressure loss on the inlet side and the pressure loss on the outlet side are not the same, there is a problem that the flow rate on the terminal side increases and uniform cooling cannot be performed over the entire width of the steel strip.

Recently, for hot rolled steel strip manufactured in a hot rolling mill, there is a strong demand for manufacturing the material in the cooling process and homogenizing the quality in the width and length directions. It is desired to improve the product quality by making the flow rate of cooling water of the upper surface cooling header pipe uniform.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems and to make a flow rate distribution of cooling water flowing out from each nozzle of a nozzle type upper surface cooling header pipe uniform in a cooling device for hot-rolled steel strip, and It is an object of the present invention to provide a nozzle type top cooling header tube for cooling a steel strip capable of cooling the strip uniformly over its entire width.

[0011]

SUMMARY OF THE INVENTION The present invention is a nozzle type upper surface in which a large number of curved nozzles are attached to the upper portion of a tubular body at predetermined intervals in the lengthwise direction with their outlets facing downward. In the cooling header pipe, a rectifying plate for partitioning the inside of the pipe into a cross shape in its cross section is provided in the length direction of the pipe in the header pipe except for one end side to which the cooling water is supplied and the other closed end side. And, at one end side where the cooling water of the header pipe is supplied, a shielding plate for shielding the upper half of the pipe body partitioned by the rectifying plate forms a gap with the inner surface of the pipe body. It is characterized in that it is attached.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a schematic vertical cross-sectional view showing one embodiment of the upper surface cooling header pipe of the present invention, and FIG. 2 is A- of FIG.
A sectional view taken along line A, FIG. 3 is a sectional view taken along line BB in FIG. 1, and FIG.
6 is a cross-sectional view taken along the line CC of FIG. As shown in the drawings, in the upper surface cooling header pipe 1 of the present invention, the pipe body has a cross shape in a cross section from one end side 1a to which the cooling water conduit is attached to the other end side 1b closed. A rectifying plate 2 that divides into four partitions is attached. The straightening vanes 2 are not attached near the both ends of the one end side 1a and the other end side 1b of the header pipe 1, but are attached in the length direction of the pipe body from a position separated from the both end portions by a predetermined distance. There is.

As shown in FIGS. 1 and 4, the header tube 1
Except for one end side 1a and the other end side 1b, a large number of curved nozzles 4 and 4 are arranged at predetermined intervals in the length direction of the pipe body in the upper part of the left and right symmetrically with the outlet 4a facing downward. It is provided. Then, on one end side 1a of the header pipe 1, as shown in FIG. 2, a shield plate 3 for shielding the upper half part of the pipe body partitioned by the cross-shaped straightening plate 2 is attached. A gap 5 is formed between the shield plate 3 and the inner surface of the tube.

Most of the cooling water supplied to the header pipe 1 from a conduit pipe (not shown) attached to the one end side 1a of the header pipe 1 is attached to the one end side 1a of the header pipe 1, and the upper half of the pipe body is attached. Is passed through the lower half of the tubular body partitioned by the rectifying plate 2, is inverted at the other end side 1b of the header pipe 1, is guided to the upper half of the tubular body, and is attached to the upper portion of the tubular body. It flows out from the nozzles 4 and 4. Further, a part of the cooling water supplied from the conduit to the header pipe 1 flows into the upper half of the pipe body through the gap 5 between the shield plate 3 and the inner surface of the pipe, passes through the upper half of the pipe body, and It is ejected from nozzles 4 and 4 attached to the upper part of the body.

As described above, the inside of the header pipe 1 is partitioned by the cross-shaped straightening plate 2, and the one end side 1a of the header pipe 1 is provided with the shield plate 3 for shielding the upper half of the pipe body. Therefore, most of the cooling water supplied from the one end side 1a of the header pipe 1 flows into the lower half part of the pipe body, and the other end part 1b of the pipe body 1b.
To the upper half of the pipe, and a part of the cooling water flows from the one end 1a of the pipe through the gap 5 between the shield plate 3 and the inner surface of the pipe to the upper half of the pipe. It spouts from nozzles 4 and 4 attached to the upper part.

Further, inside the header pipe 1, a rectifying plate 2 is attached which divides the inside of the pipe into four cross-shaped sections in a cross section from one end side 1a to which the cooling water conduit is attached to the other end side 1b. Therefore, the amount of the cooling water supplied from both ends of the pipe body into the header pipe 1 becomes uniform, the variation in the flow amount is eliminated, and a uniform flow amount distribution is obtained.

Therefore, as a result of the cooling water having substantially the same pressure being supplied into the header pipe 1 from both ends of the pipe body, the nozzles 4 and 4 are formed.
Therefore, it becomes possible to make a uniform flow of cooling water having no dynamic pressure flow down on the steel strip. FIG. 5 is a water amount density (distribution) of the cooling water flowing out from the nozzle of the header pipe of the present invention.
It is a graph which shows. From FIG. 5, it can be seen that a substantially uniform water amount density is obtained in the plate width direction of the steel strip.

According to the present invention, the pressure distribution in the upper surface cooling header pipe at each mounting position of the laminar flow nozzle can be made uniform, the dynamic pressure does not act over the entire width of the steel strip, and the cooling of the uniform flow distribution is performed. Water can be poured. Therefore, it is possible to cool the steel strip uniformly over its entire width.

[0019]

As described above, according to the apparatus of the present invention, in the cooling apparatus for hot rolled steel strip, the flow rate distribution of the cooling water flowing out from each nozzle of the nozzle type upper surface cooling header becomes uniform, and Industrially useful effects can be obtained in which the strip can be uniformly cooled over its entire width uniformly and with high precision.

[Brief description of the drawings]

FIG. 1 is a schematic vertical cross-sectional view showing an embodiment of a top surface cooling header of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 1;

FIG. 5 is a graph showing a water amount density of cooling water flowing out from a nozzle of a header pipe of the present invention.

FIG. 6 is an explanatory diagram showing types of nozzle type upper surface cooling headers.

[Explanation of symbols]

 1 Header pipe 1a Header pipe one end side 1b Header pipe other end side 2 Straightening plate 3 Shielding plate 4 Nozzle 4a Outlet port 5 Gap

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Miyamoto The first place in Kokancho, Fukuyama City, Hiroshima Prefecture Fukuyama Kyodo Kiko Co., Ltd.

Claims (1)

[Claims] 1. A nozzle type upper surface cooling header pipe in which a large number of curved nozzles are attached to an upper portion of a pipe body at predetermined intervals in a lengthwise direction with the outlets thereof facing downward. A rectifying plate for partitioning the inside of the pipe into a cross shape in its cross section is provided in the length direction of the pipe except the one end side to which the cooling water is supplied and the other closed end side, and the header is provided. On one end side where the cooling water of the pipe is supplied,
A nozzle-type upper surface cooling header pipe for cooling steel strip, characterized in that a shielding plate for shielding the upper half of the pipe body, which is partitioned by the flow straightening plate, is attached with a gap from the inner surface of the pipe body. .