JPS62183902A - Cross rolling down method for hot slab by press - Google Patents

Abstract

PURPOSE:To improve the width accuracy of a slab by providing side guides to the upper stream on the inlet side of dies and cross rolling down the front end of the slab then cross rolling down the unrolled down part at the rear end of the slab after centering with the side guides. CONSTITUTION:The side guides 5 are installed to the paper stream side of an inlet side roller table 3 of the dies 1 and the slab 4 is first continuously cross rolled down from the front eend thereof up to a prescribed length. The space between the dies 1 is then expanded and the slab 4 is advanced. The rolling down gap of the dies 1 is adjusted in the prescribed position and the rear end of the slab 4 is subjected to preforming. After the dies 1 are expanded in succession thereof, the slab 4 is retreated and is subjected to centering by the side guides 5, then the rear end is cross rolled down. The generation of a center deviation of the slab 4 and the step in the longitudinal direction thereof is prevented by the above-mentioned method. The accuracy of the finish width of the slab 4 is thus improved.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for reducing the width of a hot slab using a press.

"Prior Art" As a width reduction method for hot slabs, the so-called V-H rolling method is generally performed, in which engine rolling using vertical rolls and horizontal rolling using horizontal rolls are repeated.

However, in recent years, from the perspective of promoting synchronization between continuous casting lines and hot rolling lines and improving energy loss and process loss, slab width types have been consolidated in continuous casting lines and slab widths have been changed in hot rolling lines. There are many examples of adopting a combination of sizing, and width sizing technology in hot rolling lines is attracting attention as an important issue for synchronizing continuous casting lines and hot rolling lines.

Regarding this width sizing technology, the above-mentioned V-H rolling method has limitations in width rolling J ratio, processing efficiency, front and rear end cropping, etc. As an alternative sizing technology, hot rolling using a press, which was filed by the applicant, has limitations. There is a method for reducing the slab width (
(See Japanese Patent Application Laid-Open No. 60-203303).

As shown in FIG. 2, this method of reducing the width of a hot slab using a press has sloped parts fat1c on the entry side and the exit side,
A pair of left and right molds 1 having a parallel portion 1b in the middle is controlled by a hydraulic cylinder 2 to a predetermined width reduction interval and an expansion interval of width reduction interruption, and is controlled by roller tables 3 on the entrance and exit sides of the mold 1. This is a method in which the width of the hot slab 4 is reduced while moving the hot slab 4 forward and backward between the molds 1.

In detail, as shown in FIGS. 3 and 4, the entrance side of the mold l (IN oblique part 1a and parallel part 1b, the space between the molds 1 is immediately expanded and the slab 4 is moved forward as it is. When the rear end of the slab 4 is located at a predetermined position on the exit side of the mold 1, the fifth As shown in FIG. As shown in FIG. 7, the space between the molds 1 is immediately widened and the slab 4 is moved backward, and when the rear end of the slab 4 is located on the entrance side of the mold I, the space between the molds 1 is expanded as shown in FIG. is set to a predetermined width reduction interval, the slab 4 is moved forward, and the unrolled lower part at the rear end of the slab 4 is width-reduced by the entrance inclined part 1a and the parallel part 1b of the mold 1.

[Problems to be Solved by the Invention] By the way, when the hot slab 4 is width-reduced by the mold l as described above, the cross-sectional shape of the slab 4 has a tongue-bone-like shape as shown in FIG. The contact surface between the lower surface of the slab 4 and the roller table 3 is extremely small, and as shown in FIGS. 5 and 6, when the slab 4 retreats, the roller table 3 and the slab 4 slightly contact Due to the change in condition, the slab 4 meandered, and the slab center when the width of the rear end of the slab 4 was subsequently reduced was misaligned with the previous slab center, resulting in a step in the finished width. There was a problem that product quality was compromised.

"Means for Solving the Problems" The present invention has been made to solve the conventional problems as described above.

That is, the present invention provides a hot slab 4 as shown in FIG.
fIJ! on the entry and exit sides of the direction of travel. A side guide 5 for centering the slab 4 is provided on the upstream side of the roller table 3 on the entry side of a pair of left and right molds l having a diagonal part 1stlc and a parallel part 1b in the middle. , as shown in FIG. 4, with a predetermined width reduction interval between the molds 1, a predetermined length from the tip of the advancing slab 4 is continuously rolled by the inclined part 1a and the parallel part 1b of the mold 1. After rolling down the width, immediately expand the space between molds 1 and
When the t&K of the slab 4 is at the predetermined position on the exit side of the mold l, as shown in Fig. 5, the space between the molds 1 is adjusted to a predetermined width reduction interval, and the slab 4 is After the rear end is preformed by the outlet inclined part IC of the mold 1, as shown in FIG. As shown in Figure 1, centering of the slab 4 is performed by sandwiching the unrolled lower part of the rear end of the slab 4 between the numbered guides 5, and then, as shown in Figure 7, the space between the molds 1 is reduced by a predetermined width. At the same time, the slab 4 is moved forward, and the uncompressed lower part of the rear end of the slab 4 is placed on the entrance side 1IJl of the mold l, at the inclined part la.
The width is reduced by the parallel portion 1b.

Note that the forward distance of the slab 4 after the centering of the slab 4 is relatively small because it is only the advance for reducing the width of the unrolled lower part at the 1 & end portions of the slab 4. 4. The meandering that occurs during the forward movement is not much of a problem.

"Example" Length 9800mm ~ 10300m, thickness 220+
20 hot slabs each having a width of 1,500 wn and a width of 1,500 mm are alternately reduced in width to a slab width of 1,200 mm without centering the slabs as in the conventional method, and in the case in which the slab width is reduced by centering the slabs as in the present invention. 1200m
When compared with the case where the width is rolled down to m, it is found that when using the conventional method, the initial width rolled part from the tip of the slab to a predetermined length and the width rolled part of the unrolled part at the i & end of the slab are reduced by 5. There were 3 pieces with steps larger than cranes, but when using the method of the present invention, 1 piece with about 211 steps was obtained.
This was just an occurrence.

"Effects of the Invention" As described above, the method of the present invention performs centering of the slab before finally reducing the width of the unrolled lower part at the rear end of the slab, so that There is almost no difference in level between the original width rolling part and the width rolling part of the unrolled part at the rear end of the slab, which can contribute to improving the accuracy of the finished width of the slab.

[Brief explanation of drawings]

Fig. 1 is a plan view showing the method of the present invention, Figs. 2 to 7 are plan views showing the sequence of the conventional width reduction method for hot slabs, and Fig. 8 is a cross section of the width-reduced slab. It is an explanatory view showing an example of a shape.

Claims (1)

[Claims] A predetermined width reduction interval is set between a pair of left and right molds having inclined parts on the entry and exit sides in the advancing direction of the hot slab and a parallel part in the middle, and a predetermined length from the tip of the advancing slab.
After continuous width reduction by the entrance inclined part and parallel part of the mold, the space between the molds is immediately widened and the slab is advanced as it is.
When the rear end of the slab is located at the predetermined position on the exit side of the mold, adjust the space between the molds to a predetermined width reduction interval, and align the rear end of the slab with the slope of the exit side of the mold or parallel to the slope. Immediately after preforming by the section, the space between the molds is widened and the slab is moved back as it is, and when the rear end of the slab reaches a predetermined position, the space between the molds is set to a predetermined width reduction interval, In a method in which the slab is advanced and the unrolled lower part at the rear end of the slab is width-reduced by a part parallel to the entrance inclined part of the mold, centering of the slab is performed before the width reduction of the rear end of the slab. 1. A method for width reduction of a hot slab using a press, characterized in that the width reduction of the rear end of the slab is performed after the width reduction of a hot slab.