JPS59232235A - Method for controlling cooling of hot rolled steel plate - Google Patents

Abstract

PURPOSE:To shut off always the spraying of cooling water only at the prescribed shielding width irrespectively of the snaking of a hot-rolled steel plate by detecting online the conveying position of the hot-rolled steel plate by means of a position detecting sensor in the transverse direction of the hot-rolled steel plate provided along a conveying line and controlling shut-off plates for spraying of the cooling water. CONSTITUTION:Spraying of cooling water is controlled by shut-off plates 120a, b for spraying of the cooling water disposed along both sides of a conveying line for a hot-rolled steel plate 100 so as to prevent the excess decrease in the temp. in the side edge parts of the plate 100. A position detecting sensor 400 in the transverse direction of the plate 100 is provided along the conveying line to detect online the conveying position of the plate 100. The plates 120a, b are moved to the transverse direction of the plate 100 according to the detected value. The side edge parts of the plate 100 are thus shut off correctly from the spraying of the cooling water only at the prescribed shut-off width.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling control method for hot-rolled steel sheets, and in particular, the present invention relates to a cooling control method for hot-rolled steel sheets, and in particular, cooling water spray shielding plates arranged along both sides of a conveyance line for hot-rolled steel sheets are used to cool the side edges of hot-rolled steel sheets. The present invention relates to a cooling control method for a hot-rolled steel sheet to prevent an excessive temperature drop in a portion thereof.

The hot-rolled steel sheet taken out from the continuous hot rolling mill is rolled up in a prescribed manner before being wound up in the winding machine. It is cooled by spraying cooling water on the cooling table (conveying line) until it reaches MK.

Generally, each side edge portion of a copper plate to be rolled has a larger temperature drop during rolling and a larger cooling rate of cold ff11R than the center portion of the plate width, so as shown in Fig. 1, winding leakage occurs at each side edge. The temperature tends to be 30°C to 60°C lower than the central part, and if left as it is, it will cause shape defects due to the difference in heat shrinkage in the width direction Problems such as poor performance may occur.

As a solution to this problem, as shown in Figure 2,
During cooling, a large number of blocking plates 12 having a predetermined blocking width W are provided along both sides of the cooling table 14 from each side edge portion 10a, 10b of the hot rolled steel sheet 10 toward the plate width center portion 100, and each bank By arranging the shielding plate 12 as shown in FIG. 2(C) to isolate that portion from the cooling water, excessive temperature drop in the side edge portions 10a and 10b can be gradually prevented as the side edges are approached. There are known methods of controlling people's cooling to strongly prevent it. Each blocking plate 12 is fixed symmetrically with respect to the center of the cooling table 14 on the premise that the hot-rolled steel sheet 10 is conveyed through the central portion of the cooling table 14. In addition, 16 is a finishing rolling machine, 18 is a table roller, 2o is a winding machine, and 22a, 22b are upper and lower cooling headers.

However, in reality, due to the unevenness and uniformity of the thickness of the hot-rolled steel sheet in the width direction X, the inclination of the cooling table 14, etc. The hot-rolled steel plate 10 does not pass through the center of the cooling table 14, but is conveyed biased to either the left or right side.

For this reason, the conventional cooling control method can only be used during the stable conveyance state from when the leading end of the hot-rolled mesh board 10 is wound up by the winder until the tail end can handle the finishing stand. , or even between 50 and 100
There was a meandering of mm, making it difficult to accurately cut off the predetermined cutoff width W.

If the cooling water cut-off at the side edge portions 10a and 10b is not performed in an accurate manner in the width direction
In some cases, there is a risk that it may get worse.

The present invention has been made in view of these problems, and an object of the present invention is to provide a cooling control method that can always block the side edge portion of a predetermined width regardless of the meandering of a hot rolled steel sheet. It is said that

The present invention provides a cooling control method for hot-rolled steel sheets, in which the first general feeding position of the hot-rolled steel sheet is detected online by a position detection sensor in the width direction of the hot-rolled steel sheet installed along a conveyance line. The above objective is achieved by moving the blocking plate in the width direction of the hot-rolled steel plate according to the detected value, and correctly blocking the side edge portion from the cold N water spray by a predetermined blocking width. .

FIG. 3 shows a cooling device for hot-rolled steel sheets in which the method of the present invention is adopted. To explain the construction, a cooling table 140 is provided between the finish rolling machine 160 and the winding +ffi 200, and an upper cooling header 22. A lower cooling header 220 +) is attached to the lower part of O, a. Figure 3 (B)
As shown in , the upper cooling header 220a is provided with a large number of cooling water nozzles 221a facing downward arranged at predetermined intervals in the width direction A nozzle 221b is provided facing upward. Each cooling table 140
Cooling water is injected onto the upper and lower surfaces of the hot-rolled steel sheet 100 above. Regarding the upper cooling water header 220a, the upper blocking plate 120a is connected to the lower cooling water header 220a.
Regarding 0b, a lower blocking plate 120b is provided. The upper and lower blocking plates 120a and 120b C, both sides 1
The part 100a.

Motor 300a provided separately for motor 100b.

300b is movable independently or simultaneously in the width direction
can be changed. And 400 is hot rolled m
This is a sensor for detecting the position of Ifiio in the width direction X.

The method of the present invention uses this sensor 400 to locate the detection position (j
The position in the width direction of the hot rolled steel plate 100, that is, the conveyance position, is detected online, and from the signal of this sensor 400, a specific cutoff width determined for each bank is subtracted from the signal of this sensor 400, for example, as shown in Table 1. The calculated value is calculated in calculation 11500, and this value is used as the displacement position to which the blocking plates 120a, 120b in each bank should be moved, and the motors 300a, 3 are moved by that amount.
00b, each i1! Section plates 120a, 120b (7
) It performs position control.

As a result, as shown in FIG. 3(C) and FIG.
'120b is always set following the same direction, and both side edge portions are correctly blocked from the cooling water spray by a predetermined blocking width W.

In addition, in view of the harsh environment of a hot rolling factory, the position detection sensor 400 in the width direction Although it is preferable to use a water flow type sensor (Japanese Utility Model Publication No. 52-25175) that utilizes electrical conduction, any sensor that can detect where the hot rolled steel sheet 100 is on the cooling table 140, such as a magnetic sensor, may be used. It could be something like.

Note that in the illustrated embodiment, the present cooling control method is carried out by installing water flow type widthwise position detection sensors 400 at two locations on the cooling table 140; however, the sensors 400 are installed at two locations. Not limited. Further, since there is almost no meandering immediately after exiting the finishing mill 160, the device may be simplified as a fixed type. Furthermore, Shi-Yu 300a, 30
Regarding 0b, instead of separately providing 4111il in total, one or two of these are used, and each shielding plate 120a, 12
It goes without saying that 0b may be interlocked and moved by appropriate mechanical means.

Fig. 6 shows the widthwise distribution of the winding temperature of a hot rolled steel sheet when it is cold-rolled by the method of the present invention, and Fig. The widthwise distribution of the winding temperature is shown when fJ+water is cut off. In both figures, (A> shows the leading end part of the hot rolled steel plate, and (B) shows the relatively stable central part. The plate width is 1200 parts, the finishing temperature I ¥ 850 ° C,
The winding temperature was 550 DEG C., and the cutoff widths were both as shown in Clothing 1 above.

This distribution diagram shows that when cold Nl is applied using the conventional method, as shown in Figure 7, not only is the temperature distribution in the width direction not uniform due to large meandering at the leading end, but the temperature distribution is in the middle. , due to the meandering in the central part,
The temperature distribution is slightly higher at the side edges, but when cooled by the method of the present invention, as shown in Figure 6,
It can be seen that despite the meandering of the hot-rolled steel sheet, the temperature distribution is uniform in both the leading end and the center.

As described above, according to the present invention, regardless of the meandering of the hot-rolled steel sheet, it is possible to always correctly cut off the cooling water spray only by a predetermined cutoff width. This effect is particularly remarkable in the hot-rolled 6N provisional leading end and tail end portions where the degree of meandering is large. As a result, it is possible to achieve the effect that product quality is improved, particularly shape improvement and material uniformity are achieved to a higher degree and with a higher yield.

[Brief explanation of the drawings] Figure 1 is a temperature distribution diagram in the width direction of a hot-rolled steel sheet showing the cooling characteristics when no cooling control is performed, and Figure 2 (A) and (B)
(C) is an explanatory diagram including a partial block diagram of a cooling device in which a conventional hot-rolled steel plate cooling control method is adopted; (A>
is a front view, (B) is a side view, (C) is a plan view, and FIGS. (A> (B) (C) equivalent figure, Figure 4 is a figure equivalent to Figure 3 (B) showing the state where the shield plate follows the meandering of the hot rolled steel plate, Figure 5 (△) (B) is , is an explanatory diagram showing an example of a position detection sensor, in which (A) is a front view, (B) is a side view, and Fig. 6 (A>
(B) is a temperature distribution diagram in the width direction of the hot rolled steel sheet cooled according to the present invention, (△) is the leading end portion, (B)
7 (A>(B)) shows the central part, and FIG. It is a distribution diagram corresponding to A>(B,). 10.100...hot rolled steel plate, 10a, 10b, 100a, 100b =--side edge portion, 22a1220a...upper cooling header, 22
b, 220b...lower cooling header 400...position detection sensor, X...width direction of hot rolled steel plate, W...predetermined cutoff width. Agent Takaya Ron (and 1 other person) Fig. 1 Fig. 2 (A) Fig. 2 (B) (C) l112 10 Fig. 3 (A) (A) No. (A) Board Width 6 Fig. (B) Figure 7 (B) Yuruhata

Claims (1)

[Claims] Cooling of hot-rolled steel sheets is performed so as to prevent an excessive drop in temperature at the side edges of the hot-rolled steel sheets by blocking plates for cooling water spray disposed along both sides of the hot-rolled steel sheet conveyance line. In the control method, the conveyance position of the hot-rolled steel plate is detected online by a position detection sensor in the width direction of the hot-rolled steel plate provided along the conveyance line, and the shielding plate is moved in the direction of the hot-rolled steel plate according to the detected value. A method for controlling cooling of a hot-rolled steel sheet, characterized in that the side edge portion is moved in the width direction to correctly block the cooling water spray by a predetermined blocking width.