JPH04200816A - Lower cooling device for hot rolled steel plate - Google Patents

Abstract

PURPOSE:To prevent the scattering of cooling water by providing a box header between the outlet side of a lower apron and the entrance side of a looper roll and attaching a nozzle plate, which doubles as an apron and is provided with many drill holes for spraying cooling water, to the top. CONSTITUTION:A cooling device 1 is disposed between a lower apron DE and a looper frame LF. A nozzle plate 2 is provided with many drill holes 2-1. Cooling water is supplied through a feed water hole 4, and this cooling water is sprayed through the drill holes 2-1 on a steel plate to exert cooling. The diameter (d) of the drill holes and the total number (n) of these drill holes are regulated so that they satisfy inequalities I, II, where w0 is the maximum width of hot rolled steel plate, Q is the whole quantity of cooling water, (v) means equation III, H is the maximum height of passing position of hot rolled steel plate from the top of the nozzle plate, and (h) means the height from the hot rolled steel plate to the upper end of a sprayed water column and is not shorter than 0.1m. By this method, the occurrence of scattering of cooling water can be prevented, and also superior cooling effect can be provided.

Description

[Detailed description of the invention] <Industry 1. FIELD OF APPLICATION 2 The present invention relates to a cooling device for cooling hot-rolled steel sheets at 78°C, and in particular, the present invention relates to a cooling device for cooling hot-rolled steel sheets at 78°C, and in particular, the present invention relates to a cooling device for cooling hot-rolled steel sheets at 78°C, and in particular, the present invention relates to a cooling device for cooling hot-rolled steel sheets at 78°C, and in particular, for cooling hot-rolled steel sheets at 78°C, in particular,
The present invention relates to a lower cooling device suitable for cooling the toe surface of a steel plate during rolling.

<Conventional technology> Hot continuation I? A cooling device (hereinafter referred to as stream coolant) for cooling the hot-pressure 1Lm plate is installed between the stands of the finishing mill (hereinafter referred to as F finishing mill).

Conventionally, this strip coolant is usually sprayed with pressurized water at a water pressure of 2...20 kgf/c. ! j”
The steel pipe Nosruha Lada, which has been cut in large numbers in the width direction of the plate, is subjected to hot pressure on a finishing mill stand l'ijl.
The pressurized water is cooled by blowing the pressurized water onto the steel plate surface Q1.

, two conventional examples are shown in FIG.
Showing the stand. The stand in this example is a 6-tier mill, with upper and lower workpieces. , LWlg, 4
``Top'' Inner roll UI R, i...! R110F Backup roll LJ i31'?, L, B
The m1 plate S retracts in the direction of the arrow.

Furthermore, a pre-heli guide DG is provided on the exit side of the 1-work 1-call IJ WR.
The output of R (Breco 1.l: lower nib L2 n r>r> is provided to guide the plate S to the Louvano L・-1, L P (.l-1R is a predetermined tension applied to the steel plate S). It is 1 [harbor 11-] to make (''-'j. In addition, 1.J R
C is hu-le courant 1-header, L RCεJ lower 1-
1-le coolant\Tsuda, SC is 1st-) stand 1
``Person measurement'' A I guide is shown.

Gonoyo・）na-shi-1 Nimir's stun 1 slip 1 slip coolan I・(、。 warehouse--top side is Puri Heli Gai I' D
Installed in C and in housing part 7 on the entrance side of stand 1)
71□ □ Lada US C,, US
C,, t'= From d, lower side 1/section apron DE and looper fly J, 1. Between F and louver o-/l/
I-, R and i1) Stand entrance guide l”S
Between D and G,'', there is a T section provided - runt header L S
C+, I, and SC7, respectively.

Note that these configurations are substantially the same on the other exit sides of the finishing mill except for the final stand 1111 side.

? Problems to be Solved by the Invention〉 The above-mentioned conventional strip-cooling system between the machine and the L-mill stand has a main flow of cooling water of 4 to 20 k.
g f / c + fl, and since it is sprayed onto the steel plate by a spray nozzle, the scattered water droplets are
Due to the poor atmosphere between the stands, the negative impact on various equipment was unavoidable, and the installation of various sensors between the stands was desired to be resolved in the 111th period.

In addition, I used Laminaf instead of the strip coolant spray nostle! Although it is possible to solve this problem by adopting a cone nozzle, it is difficult to apply a lower strip coolant cone nozzle. For example, in Ishikawajima-Harima Technical Report, Vol. 1, No. 4, pages 293-299, it is disclosed that it is applied to a carden wall cooling, but this is an example of application to a run-out table on the exit side of the machine, and the louver between the stands is disclosed. exists and the passing position of the steel plate fluctuates greatly.

Furthermore, Japanese Patent Application Laid-open No. 55-156612 discloses a method in which a column of water is blown from a nozzle below the water surface, and after cooling the lower surface of a steel plate, the water is dropped into a water tank! A method for reusing water has been disclosed, but even if the amount of mercury used can be reduced, the temperature of the water in the tank will gradually rise and the amount of cooling movables will decrease.

Furthermore, a method has been developed in which the top surface of a steel plate is further cooled with a large number of water and ports, but a method using C2 between the stands of a finishing mill has not yet been disclosed.

The present invention prevents the splashing of cooling water caused by the slip-slip coolant, thereby preserving various equipment between scunds, making it possible to install sensors between stands, and cooling the slip-slip coolant itself. It is an object of the present invention to provide a lower cooling device for hot-rolled steel plates that can also improve effects.

<1' to solve the problem. The lower cooling device for hot-rolled steel plates according to the present invention is installed in the lower cooling device for hot-rolled steel plates for cooling the steel plate being rolled between the stands of a hot continuous finishing mill. Install a bonx henoder between the lower apron outlet side and the looper roll inlet side on the outlet side, and install a nozzle plate that also serves as an apron and has many drilled holes for cooling water spout on the L side of the box/ladder. As a result, the drilled holes provided in the apron-cum-nozzle plate may also meet the following conditions (
4 straight 9 d and 1 scale having a total number of n solve the problems of the prior art described above.

d-n>0.8+v.

Katagogode wo: Maximum hot rolled steel plate width (2: Total cooling Mercury v = I';l'τ-''T-T stop 'j'111: Eb
Double-use nozzle brake 1/Hot rolled steel plate 1 from the top
th passing position height 11: Height from hot rolled steel plate to ejected water column - L end
h 50.1m <Function> F Work 1: A honks/rudder is installed between the lower apron exit side of the toll exit side and the louver roll entry side, and a number of drilled holes for cooling water spout are installed on the top surface of the box. By installing the nozzle play I- (hereinafter referred to as the single-hole nozzle L--1-), which also serves as a single-purpose nozzle, a large number of It is 17 so that the steel plate can be cooled by ejecting a water column.

Furthermore, by relating the diameter (1 and total number n, l:, steel plate width W, and the required height of the water column!-1+h) of the drill holes provided in the nozzle plate 1, It becomes possible to suppress the scattering of cooling water as much as possible, to uniformly cool the steel plate in the width direction, and to improve the cooling effect of the cooling water.

To find these conditions, the following investigation was conducted.

First, we investigated the height of the water column ejected from the drill hole, and found that between the stands of the finishing mill, the passage position of the annual plate changes due to the operation of the Ruparol, so the height of the water column is determined by the highest passage position ( At least HlOm than the steel plate in H)
It was found that it was necessary to increase the height by m (h-0,1 m). In this case, the flow rate V of the cooling water passing through the through hole must be V-Fll-7-T■]1] or more. As a result, for a given total cooling Mercury Q, the diameter d of the cut hole and the total number of holes have the following relationship.

FIG. 4 shows the results of an experiment in which a steel plate was cooled while satisfying the relationships among d, n, Q, and v in 1-1.

The steel plate and L7 are the maximum width W that can be rolled with a minus finish of 1 mm.

The height 1cm from the nozzle plate to the highest passing position of the steel plate is 600i+m, and I-1+h = 0.7
+n.

According to No. 4 and 1, the value of dXn is the steel plate width W. Two points are clear: 0.8 times or more is sufficient. In addition, in the figure, Δ,
The evaluation of B, C, and D is as follows: A: Uniform cooling + iJ performance ■3: Water film breakage (cylinder frame-like) may occur but disappears quickly C: Water film breakage occurs and remains until the next stand■ ) This is due to the judgment result that the material does not have a constant V in the width direction of the two steel plates.

Therefore d−n≧0, 8w.

shall be.

, -, dXn was 0.8wo□0.9w, and slight streaks may appear in the vicinity, but they disappeared by the time of next stand rolling, and there was no problem with crystalline 1-. In addition, above 1
1 should be 100 mm or more -L, and there are no special restrictions on the upper limit, but the point is to prevent the loss of F4 of the cooling water, and if Q is too large, the drill hole diameter d will inevitably become smaller, making the nozzle more likely to clog. There is a problem with this, so it is desirable to set the maximum length to about 1500 mm.

<Example> An example of the present invention will be described with reference to FIGS. 1 to 3. 1M is a sectional view along the rolling direction of the lower cooling device L installed in the present invention on the exit side of the i-th stand of the finishing mill;
The figure is a plan view of the steel plate, showing half of it in the width direction of the steel plate. Figure 3 is a detailed explanatory diagram of Figure 1.

Figure 1 (here, IJC is preheli guide I) I
Although the structure is such that the flannel 1 is cooled by a 4-part cooling device installed inside the flannel 1 and a helaminar water film Q, ℃, a detailed explanation will be omitted here.

In the present invention, the i-th stand exit lower nib 1-1 D, the louver 1/-mm LF, and the louver roll 1-R are the same as before. And the lower cooling device 1 has a lower nib n:y
It is installed between DE and louver 7 rays 1 and LF. Lower Cooling Device] LJ: Nozzle plate 12 is installed on the -L side of the 21-shaped box header 1-1 with one side open.
The nozzle base is inserted into the nozzle base and fastened with bolts (not shown) via 1 and 3. The nozzle play L 2L is divided into two parts in the width direction C1 of the plate S.
In this example, it is divided into five parts), and a large number of drill holes 2-1 are arranged, but the drill holes 2-1 are arranged diagonally so that they are not sprayed at the same location in the width direction of the steel sheet in progress. Therefore, nozzle plays 1-2A, 2B.

2C... also has a diagonal shape (2 pcs. = 1 parallel to the hole row) at the mutually adjacent portions.

Further, 4 is a cooling water supply port, and in this example, 4. ,
, -1.4-2.

A partition plate 1- is provided between the nozzle plates 2Δ and 2B.
2 is placed inside the box header 1-1, and the inside of the box header 1-1 is made into a plurality of chambers so that it can accommodate the width of the steel plate to a certain extent. Note that the opposite side in the width direction of the steel plate (not shown) is similarly configured. In the case of this configuration, the water supply pipes (not shown) to water supply ports 4-i and 4-2 are turned on as separate systems, respectively, and
It is natural to be able to control it.

The inverted U-shaped hardware 5, whose number is not shown in Figure 3, is for dispersing cooling water, and is provided over the entire length (width direction of the steel plate) of each chamber in the box header 1-1. Open the hole 5-1 and connect the water supply port 1-1. It is installed for the purpose of diffusing the cooling water supplied from 4-2 so that it does not flow directly into the drilled hole 2-1 of the nozzle plate 2.

Also, nozzle base play +/3 is nozzle I/-
1-2A, 2B, 2C... are divided in the width direction of the steel plate, so they are interposed as seals 2 to prevent cooling water from leaking from these parts. A drill hole 3-1 having a slightly larger diameter than the drill hole 2-1 is drilled at a position corresponding to the drill hole 2-1.

Here, the bonks and soda 1-1 are attached to the mill housing +Ig via the bracket and throat BC (as shown in the figure, the rear end side is a little higher), so the rear ends of the nozzle plates 1 and 2 are also slightly higher. In this state, the tip of the steel plate S entering from the lower J7' Ron DE can be passed through without any trouble. That is, in the present invention, Lj nozzle 2 is J-, which also serves as the apron of this part.

Furthermore, G (not shown) is a guide plate 1 provided at the center in the width direction of the steel plate, and is located downstream of the nozzle plate 12.
tJiEsworu・baframe1. ．． In order to prevent smooth delivery to F, it is fixedly attached to the box header 1-1.

In the lower cooling chamber according to the present invention configured as described above, the diameter d of the drill holes 2-1 and the total number of holes 11 are set as shown in Table 1, and the maximum copper plate width is 2200 m111, and the total cooling water @ Q
It was applied to equipment requiring -23001,/min.

, -2, as shown in Fig. 1 61'', the height H of the highest passing position S of the steel plate S is the highest position LR'4 of the looper 1-1-R, and the corresponding height H-60011 m. was adopted, and the difference h between the upper end of the water column ejected from the drilled hole 2-1 of the nozzle 1.-1-2 and the 'vA plate S was set to 100 mm.

That is, at this time, the flow rate V of the cooling water passing through the drill hole 2-1 is expressed as V=x, yx, -t-tl)TT=
The total number n of drill holes was determined as 3.7 m/sec.

As seen from Table 1, in the case of all 7, dXn>0.8W
O was satisfied, and the steel plate could be cooled uniformly in the width direction. However, in case of gate 3, dXn・−1,4
Although the through holes are arranged very densely (5Wa), because the through hole diameter d is small, they are easily clogged with fallen scale and water impurities, resulting in a situation where the cooling water is not spouted uniformly. From this point of view, d°n#w is practical.

It is desirable to set it as 2.

We also investigated the heat transfer coefficient and found that with the same amount of water, we were able to obtain a cooling effect approximately 1.5 times greater than that of the one-spray cooling system. In spray cooling, water jetted from a nozzle at high speed (usually about 20 m/sec) hits the bottom surface of the plate and is immediately reflected back to zero, leaving no space to contribute to cooling. When using a multi-hole nozzle with many holes, the cooling water jetting speed should be 3 to 5 m/sec.
It is presumed that since the cooling water that has hit the steel plate-F side stays there for a while and does not fall off, the cooling capacity is the same.

<Effects of the Invention> The F section cooling device for steel plates according to the present invention includes a box pad/ladder between the F section apron on the exit side of the finishing mill stand and the louver frame, and a drill hole for spouting cooling water on the top surface of the box header. Nozzle play 1- that can also be used as an apron with a large number of
Since the diameter and total number of the drilled holes, the total amount of cooling water, and the jetting speed are selected within the optimal range, there is no splashing of cooling water at all, and the cooling effect is greatly improved without increasing the amount of cooling water. It is now possible to do away with the strip clamps 1 to 1 in the later stage, which previously had two sets of upper and lower strip clamps installed between the stands.

Therefore, each device between the stands is sufficiently protected, various sensors between the stands can be easily installed, and the amount of cooling water can be halved, which is also useful for reducing operating costs.

[Brief explanation of the drawing]

Figures 1 to 3 are detailed explanatory diagrams of the present invention, and Figure 1 is a sectional view along the rolling direction ζ of the lower cooling device according to the present invention installed on the exit side of the first stand of the finishing mill. , FIG. 2 is a plan view, and FIG. 3 is a detailed explanatory diagram of FIG. 1. FIG. 4 is an explanatory diagram of cooling evaluation for the product of the diameter of the through holes and the total number thereof, and FIG. 5 is an explanatory diagram of the arrangement in the conventional strip crank 1. DESCRIPTION OF SYMBOLS 1... Lower cooling device for hot rolled steel plate, 1-1... Box header, 2... Nozzle plate that also serves as apron, 2-1... Drill hole, Engineering 5 3... Nozzle hair spray 1 -8 4...Water inlet 1) E...Lower apron, Lri'...Louver frame, L R...Louper roll. Patent applicant: Kawasaki Steel Corporation

Claims (2)

[Claims] (1) In a lower cooling device for hot rolled steel plates for cooling steel plates being rolled between stands of a hot continuous finishing rolling mill, between the lower apron exit side of the lower work roll exit side and the looper roll entry side. 1. A lower cooling device for a hot-rolled steel plate, characterized in that a box header is provided, and a nozzle plate that also serves as an apron is attached to the top surface of the box header, and has a number of through holes for spouting cooling water. (2) The lower cooling device for a hot-rolled steel plate according to claim 1, wherein the through holes provided in the nozzle plate that also serves as an apron have a diameter d and a total number n that meet the following conditions. d・n≧0.8w_o and d^2・n≧4/π・Q/v where w_o: Maximum hot rolled steel sheet width Q: Total cooling water amount v=√2g・(H+h) H: Nozzle plate that also serves as apron Highest passing position height of the hot rolled steel plate from the top surface h: Height from the hot rolled steel plate to the top of the jetted water column h≧0.
1m