JPH04300013A - Descaling header on inlet side of hot continuous finishing rolling mill and descaling device - Google Patents

Abstract

PURPOSE:To provide the header with variable injection width in which a nozzle pitch is made the same as other parts even if chambers are divided with partitions, and also the rapid temp. deviation a the tip end part of a sheet bar is eliminated. CONSTITUTION:On the partition 13 provided between chambers 14, 15, a communicative hole 16 which is communicated with one chamber 14 and opened to an outer face of the partition is provided, the nozzle 7 is attached at the opening 17, and this partition is used as a part of the header 10. Also, among the plural headers on the inlet side of the finishing rolling mill, at least one of the header conduits is equipped with a flow rate regulating valve, and the water quantity for descaling is made to be gradually increasable with this valve, and the generation of the rapid temp. deviation at the tip end of the sheet bar prevented.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a descaling header and a descaling device used on the entry side of a continuous hot finishing rolling mill, and particularly to a descaling header and a descaling device that can change the jet width of high-pressure water. This invention relates to a descaling device that can maintain a uniform temperature at the tip of a rolled material.

0002

2. Description of the Related Art A material to be rolled that is rolled in a continuous hot rolling mill is descaled by injecting high-pressure water at the entrance side of a continuous finishing mill (hereinafter simply referred to as finishing mill). in this case,
There are various widths of the material to be rolled (hereinafter referred to as sheet bars), and if you always use a descaling header with a spray width that matches the maximum width of the sheet bar, extra high-pressure water will be required, and the power of the high-pressure pump will be reduced. Not only is it wasted, but the high-pressure water jetted from the descaling nozzle located outside the seat bar side end scatters around the descaling nozzle and adversely affects nearby devices.

[0003] As a countermeasure for this, for example,
As shown in Publication No. 81414, the descaling nozzles (hereinafter simply referred to as nozzles) attached to the descaling header are divided into two groups: those adapted to the minimum sheet width and those capable of spraying up to the maximum sheet width. When descaling, some other nozzles are closed with fluid-operated valves. Further, as in Japanese Utility Model Application Laid-Open No. 60-71418, there is a descaling header in which a piston is provided in the descaling header, and the piston cuts off high-pressure water supplied to an arbitrary number of nozzles at both ends of the descaling header.

However, since the high pressure water used for descaling is at a high pressure of 150 to 200 kgf/cm2, the presence of moving parts in the descaling header is not desirable as it may cause failure. Therefore, Figure 5
As shown in the figure, the descaling header 1 is divided into a plurality of chambers 2, 3, and 3 by a partition wall 6, and high-pressure water supply pipes 4, 5, and 5 are attached to the chambers 2, 3, and 3, respectively, and high-pressure water (not shown) is attached to the chambers 2, 3, and 3. High-pressure water is supplied from the piping through a spray valve, and only chamber 2 is used for narrow seat bars, and all chambers 2 and 3 are used for wide seat bars.
, 3 are used to inject high pressure water from the nozzle 7.

Further, in the descaling device on the entry side of the finishing rolling mill, descaling is performed by arranging a plurality of pairs of upper and lower descaling headers in the direction of movement of the sheet bar. This situation is shown in FIG. In the figure, the sheet bar S advances in the direction of the arrow toward a finishing mill (not shown). The descaling device 20 is provided with two sets of descaling headers 21, 21, 22, 22, which are a pair of upper and lower sheets in this example, on the entry side of the finishing rolling mill.
are installed along the traveling direction of the pipes 25, 2.
The spray valves 23 and 24 installed in the spray valve 6 control the ON/OFF state of high-pressure water injection. In this case, for example, H
MD (thermal steel detector) 27 detects the tip of the sheet bar S, and before the tip of the sheet bar S reaches the high pressure water injection position of the descaling headers 21, 21, starts jetting high pressure water; The scale (not shown) on the surface of the sheet bar S is peeled off.

Further, the remaining scale is completely removed by the subsequent descaling headers 22, 22, but the subsequent descaling headers 22, 22 also remove the remaining scale from before the tip of the sheet bar S reaches. When injection of high-pressure water is started, this tip becomes supercooled, causing slip during finish rolling, and there is a risk that this tip will become over-thick.

In order to prevent this, immediately after the tip of the sheet bar S passes the position of the subsequent descaling headers 22, 22, the subsequent descaling headers 22, 22 are
It was designed to spray high-pressure water from the In the case of reverse rolling, as shown in Japanese Patent Laid-Open No. 63-132715, there is a technique in which high-pressure water is not injected into the tip of the rolled material to prevent overcooling of this portion.

[0008]

As shown in FIG. 5, when a descaling header is simply divided into a plurality of chambers by a partition wall 6, the thickness of this partition wall is usually 25 to 3 cm.
Since it is thick at 0 mm, the nozzle pitch in this part becomes large. This is not much of a problem in the case of slabs, etc., where the thickness of the rolled material that is subject to descaling varies greatly, as the nozzle pitch is inevitably large, but in the case of slabs, etc., where the thickness of the rolled material varies greatly, the nozzle pitch is inevitably large, so it is not a problem. On the other hand, since the distance from the sheet bar surface to the nozzle tip can be made relatively close, the nozzle pitch P is also set to be as small as 60 to 70 mm. Therefore, at the position of the partition wall 6, the nozzle pitch P'
When the distance becomes large, such as 90 to 110 mm, the descaling function is impaired only in this portion, which becomes a problem.

Furthermore, as mentioned above, in order to prevent overcooling of the seat bar tip, if high pressure water injection is started from the time the seat bar tip reaches the descaling header position, then the high pressure water The leading edge, which is not exposed to heat, becomes high in temperature, and then the temperature drops rapidly. This temperature deviation causes a deviation in plate thickness during rolling, which may force truncation due to tolerance disturbance.

This state is shown in FIGS. 7(c) and 7(d). FIG. 7(C) shows the temperature deviation in the direction of the pressed extension at the exit side of the finishing rolling mill, and FIG. 7(D) similarly shows the plate thickness deviation. A in the diagram
' and B' correspond to the tip of the sheet bar, and it can be seen that large temperature deviations and plate thickness deviations occur. Due to the characteristics based on the structure of the spray valve, this is almost instantaneous (1
Since the descaling water reaches its maximum flow rate in ~2 sec), such a rapid temperature deviation occurs between the non-cooled part and the cooled part.

The present invention solves the above-mentioned problems in the conventional technology, and provides a descaling header that does not require changing the nozzle pitch in the partition wall even if the inside of the descaling header is divided into a plurality of chambers by the partition wall. Another object of the present invention is to provide a descaling device that can prevent sudden temperature deviations from occurring at the tip of a sheet bar, and can also prevent truncation due to out-of-tolerance sheet thickness.

0012

[Means for Solving the Problems] The first aspect of the present invention is to provide a partition wall perpendicular to the axis of the header in order to inject high-pressure water to rolled materials of different widths on the entry side of a continuous hot finishing rolling mill. In the descaling header, which is divided into a plurality of chambers by a method, and is capable of supplying the high-pressure water to each chamber to change the jet width, the partition wall is provided with a communication hole that communicates with at least one of the chambers and opens on the outer surface of the partition wall. and install a descaling nozzle in this opening.
A second aspect of the present invention is a descaling device having a plurality of headers for injecting high-pressure water to a material to be rolled at the entrance side of a continuous hot finishing rolling mill, the high-pressure water of at least one descaling header being By interposing a flow rate regulating valve in the water supply pipe, the above-mentioned problems in the conventional technology are solved.

[0013]

[Function] In the descaling header according to the present invention, a partition wall for dividing a chamber into a plurality of chambers is provided with a communication hole that communicates with at least one adjacent chamber and opens on the outer surface of the partition wall. Then, the same nozzles as those for other parts are attached to the openings on the outer surface of the partition wall. By configuring the partition wall in this way, the partition wall can be used as a part of the descaling header, so that the nozzle pitch can be made exactly the same as the other parts of the descaling header.

[0014] Furthermore, the descaling device according to the present invention includes:
Among the multiple descaling headers on the entry side of the finishing rolling mill,
A flow regulating valve is interposed in the high pressure water supply line of at least one descaling header. In general, flow regulating valves are
It has a characteristic that the opening degree of the valve and the flow rate are almost proportional.
Moreover, the opening/closing speed of the valve can be controlled freely to some extent. Therefore, just before the tip of the seat bar reaches the position of the descaling header, start opening the flow rate adjustment valve.
Then gradually open it up. The time to fully open this is 5-1
0 seconds is sufficient. By doing so, it is possible to prevent a sudden temperature deviation from occurring at the tip of the seat bar.

[0015] Although the above description has been made regarding the tip of the seat bar, it is also possible to achieve uniform plate temperature by performing the reverse operation on the rear end of the seat bar, if necessary.

[0016]

[Embodiment] FIGS. 1 to 3 are drawings showing examples of partition walls used in the descaling header of the present invention. Header pipes 11 and 12 of the descaling header 10 are connected by a partition wall 13, and chambers 14 and 15 are connected. It is formed adjacent to this partition wall 13. Here, 7 is a nozzle and its pitch is p.

FIG. 1 shows an example in which one nozzle 7 is attached to a partition wall 13. A communication hole 16 that communicates with one of the adjacent chambers 14 and opens on the outer surface of the partition wall 13 is provided, and this opening 17
Nozzle 7 is attached to the. Further, FIG. 2 shows an example in which two nozzles are attached to the partition wall 13', and one of the adjacent chambers 14
Similarly to FIG. 1, a communication hole 18 is also provided from the other chamber 15 side, and a nozzle is also attached to the opening 19.

Furthermore, FIG. 3 shows another example in which two nozzles are attached to the partition wall 13''. In this case, a communication hole 16' is provided on one side of the chamber 14, and two openings 16' are provided on the outer surface of the partition wall 13''.
7 and 17' are opened and a nozzle is attached to each. By using the partition wall as a part of the descaling header in this way, the pitch p of the nozzles can be made the same as that of the other parts of the descaling header even with the partition wall. The nozzles attached to the outer surface of the partition wall can spray and stop high-pressure water at the same time as the nozzles of the chambers with which the respective communication holes communicate, and the descaling function is not impaired at all.

Note that the structure of the descaling header according to the present invention can be easily applied to headers for roll coolant, strip coolant, etc. that require changing the injection width. Next, FIG. 4 shows an example of a descaling device of the present invention, and the same equipment as in FIG. 6 is given the same reference numeral and the explanation thereof will be omitted.

In the case of the descaling device 20 shown in this figure, a flow rate regulating valve 31 is interposed in the high pressure water supply pipe 26 of the subsequent descaling headers 22, 22. The flow rate adjustment valve 31 is hydraulically driven to adjust the flow rate, that is, adjust the speed of the valve opening. Here, the spray valve 24 that has been used conventionally is installed as is, but this is not essential and is installed so that the high-pressure water can be shut off in an emergency if necessary.

The descaling device 20 of the present invention is configured as described above, and after the tip of the seat bar S is detected by the HMD 27, the tip of the seat bar S reaches the high pressure water injection position of the front descaling headers 21, 21. Just before descaling, open the spray valve 23 and spray the front descaling headers 21 and 2.
Start high pressure water injection from step 1. Similarly, the downstream descaling headers 22, 22 also begin to open the flow rate regulating valve 31 before the tip of the seat bar S reaches its high-pressure water injection position, and gradually open it fully over a period of 5 to 10 seconds. Of course, if spray valve 24 is installed, this valve 2
4 at the same time or fully open in advance.

FIG. 7(A) shows the temperature deviation in the longitudinal direction of the rolled material at the exit side of the finishing rolling mill when descaling is performed by gradually increasing the amount of high-pressure water injection. The thickness deviation is shown in Figure 7 (A), and parts A and B in the figure correspond to the tip of the sheet bar, but both the temperature deviation and plate thickness deviation are the same as those in Figure 7 (C) and (D) according to the prior art. , it can be seen that it is significantly reduced compared to part B'.

In the above-described example of the descaling device of the present invention, two
The injection amount of high-pressure water was adjusted using a flow rate adjustment valve for the later stage descaling header of the set of descaling headers, but this has the same effect even when applied to the earlier stage descaling header, and it can also be applied to multiple descaling headers. Even if it is applied to only one of the descaling headers, it has a corresponding effect, and it can also be applied to the rear end of the seat bar as necessary.

Furthermore, the injection timing of high pressure water is determined by the HMD.
Instead of using 27, it is also possible to use other sheet bar tip detection means, and it is also possible to use a known tracking means in combination.

[0025]

[Effects of the Invention] The descaling header according to the present invention has
There are no moving parts to change the jet width of high-pressure water, so there is no failure. Further, even if a partition wall is used to divide the chamber, the nozzle pitch does not become large due to the partition wall, so the descaling function is not impaired.

[0026] Furthermore, the descaling device according to the present invention includes:
Out of multiple descaling headers, at least one descaling header is equipped with a flow rate regulating valve in its high-pressure water supply pipe, which is easy to implement at low cost, and prevents sudden temperature deviations at the tip of the rolled material. can prevent the occurrence of
Furthermore, it is possible to maintain the plate thickness deviation in this part within the standard, which greatly contributes to improving the yield.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a partition wall of a descaling header according to the present invention, in the case of one nozzle.

FIG. 2 is a cross-sectional view of an example of a descaling header according to the present invention in which two nozzles are attached to a partition wall.

FIG. 3 is a cross-sectional view of another partition wall of the descaling header according to the present invention.

FIG. 4 shows an embodiment of a descaling device according to the invention,
It is an explanatory diagram of a conduit system showing equipment arrangement.

FIG. 5 is an explanatory diagram of a conventional technique of a descaling header.

FIG. 6 is an explanatory diagram of a conduit system in a conventional descaling device.

FIG. 7 is an explanatory diagram of the temperature deviation and plate thickness deviation in the longitudinal direction of the rolled material at the exit side of the finishing rolling mill after descaling by the descaling device of the present invention and the conventional descaling device; Temperature deviation in the invention, (a) is the plate thickness deviation in the invention, (c) is the temperature deviation in the prior art, (
D) is a drawing showing the plate thickness deviation in the conventional technology.

[Explanation of symbols]

1 Descaling header 2 Chamber 3 Chamber 4 High pressure water supply pipe 5 High pressure water supply pipe 6 Partition wall 7 Nozzle 10 Descaling header 11 Header pipe 12 Header pipe 13 Partition wall 14 Chamber 15 Chamber 16 Communication hole 17 Opening 18 Communication port 19 Opening 20 Descaling device 21 Descaling header 22 Descaling header 23 Spray valve 24 Spray valve 25 Pipeline 26 Pipeline 27 HMD 31 Flow rate adjustment valve

Claims (2)

[Claims] Claim 1: In order to inject high-pressure water onto rolled materials of different widths at the entry side of a continuous hot finishing rolling mill, the inside of the header is divided into a plurality of chambers by a partition wall perpendicular to the axis of the header, and each chamber is divided into two or more chambers. In the descaling header that enables supply of high-pressure water to change the jet width, the partition wall is provided with a communication hole that communicates with at least one chamber and opens on the outer surface of the partition wall, and a descaling nozzle is attached to this opening. A descaling header characterized by: 2. A descaling device having a plurality of headers for injecting high-pressure water onto a rolled material at the entrance side of a continuous hot finishing mill, the high-pressure water supply pipe of at least one descaling header; A descaling device characterized by having a flow rate regulating valve interposed in the channel.