JPS5935804A - Method for controlling edge shape of strip - Google Patents

Abstract

PURPOSE:To decrease the edge drop of a rolled plate and to improve the yield of the product by disposing vertical rolls of a vertical rolling mill between rolling mill stands in a hot rolling line and subjecting the material to cross rolling under tension. CONSTITUTION:Vertical rolls 1 of a vertical rolling mill are disposed between the stands S1 and S2 of a hot rolling mill in a hot rolling line for a steel plate. A strip 3 is subjected to cross rolling with the rolls 1 under the tension applied thereon by a difference in the peripheral speeds of the work rolls 2 of the stands S1 and S2. A dogbone 4 is formed at each side edge of the strip 3 by said rolling. The dogbones 4 are horizontally rolled with the stand S2 of the hot rolling mill in the succeeding stage whereby the edge drop is positively decreased and the product yield of the strip and the accuracy in the width thereof are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the shape of the edge of a slip plate.
- After width rolling of the lip to form a dog bone at the edge of the machine width, this is subjected to subsequent horizontal rolling C processing to modify the shape of the edge of the plate. It is.

Conventionally, methods for reducing edge bulges in the hot rolling line 1 are as follows: (a) As shown in Fig. 1, the work roll a of the hot rolling mill is deflected in the width direction. By blocking this with another actuator such as a benzoring device, the edge drop of the strip b can be reduced. Slide in the direction 1~
By flooding the edge of the lip b, the edge drop can be reduced. However, none of the methods resulted in a more aggressive improvement (reduction) in the number of drops.

The present invention aims to more actively reduce the edge drop of the slip, thereby improving the product yield and saving energy, and further improving the sheet width accuracy.

Embodiments of the present invention will be described below with reference to the drawings.

3 and 4 show an embodiment of the method of the present invention, in which a vertical roll 1 of a vertical rolling mill is placed between the front and rear hot rolling mill stands S1 and 82 in a hot rolling finishing line. The tension between the stands S+ and 82 is reduced based on the rotational speed difference between the work rolls 2 and 2 of the front and rear hot rolling mills.
- The strip 3 is applied to the lip 3, and the strip 3 is subjected to width reduction rolling using the vertical rolls 1, so that a dogbone 4 as shown in FIG. 5 is formed at the end of the strip 30 in the width direction. Next, this dogbone 4 is horizontally rolled in a subsequent hot rolling mill stand S2 to obtain a plate having the thickness shown in FIG.

As mentioned above, when width rolling is performed using the vertical rolls 1 while applying tension to the strip 3 between the stands, compared to so-called tensionless width rolling, in which width rolling is performed without applying tension to the strip 3. Since the buckling limit is improved by applying tension, the width reduction value can be increased, and since the plate is thin, the dogbone can also be grown to a large extent.

Now, if we look at the relationship between the width reduction amount and the dogbone during width rolling by applying tension, it is as shown in Fig. 7. The horizontal axis shows the width reduction ratio, and the vertical axis shows the dogbone growth. A is the raised area of dog bone 4 shown in Figure 5 (see Figure 5),
The mouth is four dogbones long (see Figure 5). Also, on the horizontal axis (Puruha is the limit width reduction tooth for tension-free width rolling)
ζ1×S1~Lip thickness).

After width rolling is performed with the vertical rolls placed between the stands as described above to form dog bones, the next stand S
When horizontal rolling is performed in Step 2, the load at the ends in the width direction becomes larger than at the center of the strip, which improves the edge drop by reducing edge drop, and also reduces the width return, reducing the amount of width adjustment. can be expanded.

Figure 8 shows an example of lead model rolling results, where A does not show the relationship between width reduction ratio and edge drop amount ratio;
B shows the relationship between the width reduction rate and the width return rate.

Moreover, X is the range in which width rolling is possible with the addition of tension, and Y is the range in which width rolling is possible without tension. Wang and Ko' are horizontal reduction ratios of 1 pass (30%), and ■ and ■' are horizontal reduction ratios of 2 passes (30%).
51%) is shown. As is clear from the figure,
It can be seen that in width rolling by applying tension f4, the larger the width reduction amount, the greater the improvement in edge drop and the larger the width adjustment amount.

In addition, when hydraulic pressure is used to roll down the vertical rolls 1 of the vertical rolling mill, the rolling can be applied with a constant load, which further facilitates the left and right generation operation of the dogbone.

As described above, according to the method of the present invention, vertical rolls are arranged between the stands of a hot rolling mill, and the strip to which tension is applied is rolled in width, so that the following effects can be obtained.

(1) It is possible to expand the amount of width adjustment in the thin plate area, and improve plate width accuracy.

0) Edge drop at the edge of the plate can be improved, yields can be improved, and energy savings can be achieved.

■Can also improve plate crowns.

(to) Other actuators, for example bending = 5
- By using the device, the effects of (ti) and (b) above can be further improved.

(v) Since the rolling mill of the vertical rolling mill is a thin plate, the amount of rolling load can be small, the equipment can be made compact, and the equipment cost can be reduced.

[Brief explanation of drawings]

Figures 1 and 2 are both front views of the conventional example, Figure 3 is a side view showing an embodiment of the method of the present invention, Figure 4 is a plan view of Figure 3, and Figures 5 and 6. 7 is a diagram showing the relationship between the dogbone and the width reduction amount, and FIG. 8 is a diagram showing the relationship between the width reduction amount, the edge drop amount, and the width return opening. 1... Vertical roll, 2... Work roll, 3... Strip, S+, 32... Rolling mill stand. 61 Figure 5 @6 Figure 33 (″) Chiki Hatai’

Claims (1)

[Claims] 1) A vertical rolling mill is installed between the front and rear rolling mill stands in a hot rolling line, and width rolling is performed with tension applied to the strip between the stands to form a dog bone at the width end of the strip. After that, horizontal rolling is performed in a subsequent rolling mill to reduce the dogbone, thereby controlling the shape of the root end of the strip.