SU973196A1 - Method of hot rolling of wide strips - Google Patents

Description

The invention relates to rolling production, and in particular to the field of manufacture of wide strips.

A known method of calibrating rolling rolls for. rolling wide strips, including rolling strips in rolls having on the barrel streams located along helical lines from the center to the edges. The method allows to exclude the tilting of the blanks in the broadening stand when rolling wide strips (l].

However, this method is characterized by insufficient band broadening. Subsequent rolling of strips with grooves on the surface in rolls with a smooth barrel can lead to tears in the strip due to uneven deformation in width, or to grooves on the surface of the finished product. 20

There is also a known method of hot rolling> rolling slabs to increase their width. The slab is rolled in several passes in calibrated rolls having projections on the barrels. Then the slab is dug in conventional cylindrical horizontal rolls £ 2J.

However, this method does not reduce the productivity of the mill. The disadvantage of this method is the difficulty of obtaining strips with a broadening of more than 10-15%, which is associated with uneven deformation of the width during subsequent rolling of calibrated slabs and, as a result, tears can form on the metal surface. In addition, the prints from the circular protrusions of the ¹⁵ rolls remain on the metal surface during further rolling.

Closest to the technical nature of the proposed is a method of obtaining a tape by editing in the direction perpendicular to the movement, followed by rolling. F3] ·

The purpose of the invention is the expansion of the assortment of the mill in width.

s 973196

The goal is achieved by the fact that in the known method of rolling strips, tapes, including rolling the workpiece in several passes, straightening with stretching and subsequent rolling, 5 after rolling in rolls with a calibrated barrel, the strips are straightened in the transverse direction.

In FIG. 1 shows a cross section of the initial slab *, in FIG. 2- cross section of the workpiece after rolling in calibrated rolls; in FIG. 3 “an intermediate section of the workpiece during the dressing process, 'in FIG. 4 - blank after dressing ', in FIG. 5 - section of the finished strip. fifteen

The method of hot rolling of wide strips is as follows.

First, the slab is rolled in special calibrated rolls and a blank with a cross-sectional shape of 20 in the form of a sinusoid is obtained in several passes (Fig. 2). The width of the workpiece remains virtually unchanged, the thickness decreases. The length of the middle line of the cross section of the workpiece in 1.3 “25

2.0 times its width (Fig. 2).

Then the stripes are straightened by stretching the workpiece by forces P, (Fig. 3). The thickness of the workpiece remains unchanged, and its width increases and ₃₀ becomes equal to the length of the midline of the cross section. The blank after this operation has the form shown in FIG. 4.

The final rolling of the workpiece is carried out in rolls with a smooth barrel. Moreover, the thickness of the strip is brought to the required.

P r. To obtain a strip of size 2.8 * 20b0 mm from 08Yu steel, a slab of dimensions 150x1600x5000 mm after heating in a methodical furnace to 1320 ° C is fed to a receiving rolling table of a hot rolling mill. The slab is transported along the rolling table in a rough descaling mill ⁴⁵ , where it is rolled in cylindrical rolls with a compression of 10%, and furnace scale is removed from the metal surface.

Next, the slab enters the rough corpse · ⁵⁰ pustan, consisting of four stands. The work rolls of the stands of the draft group are calibrated in such a way that the roll gap has the shape of a wavy line in the form of a sine ⁵⁵ .

The slab is rolled in the roughing group. They are made in three passes in the first reversing stand and one pass in the next three stands. In this case, the slab is crimped into a workpiece with a thickness of 26 mm, having a wavy (sinusoidal) shape. The workpiece is 1600 mm wide and about 29 m long.

The workpiece enters the intermediate roller table, where it is straightened in the direction perpendicular to the movement of the strip, by stretching in a sheet straightening stretching machine. The workpiece is clamped at the side edges and stretched until a rectangular cross section is obtained. In this case, the strip width increases to 2060 mm.

Further metal rolling is performed in the finishing group of the mill.

On existing hot rolling mills, wide strips are obtained by rolling in an expansion stand. In this case, a turn of the workpiece is necessary, which, in turn, reduces the length of the strip and reduces the productivity of the mill.

It is impossible to obtain significant broadening by rolling in special calibrated rolls without turning the strip due to the uneven deformation during further rolling in rolls with a smooth barrel.

The proposed method for hot rolling of wide strips in comparison with the known one allows one to obtain practically any desired strip width within the roll barrel length when rolling directly without turning a slab 90 ° in an expansion stand, to use longer and heavier slabs for rolling wide strips, which increases productivity as hot rolling mills, as well as technological units in cold rolling shops when used for processing wide strips of large weight, and also improves the quality of the metal due to ensheniya number of different thicknesses ends of the strips. The implementation of the invention allows to increase the productivity of the mill 2500 hot rolling by 300 thousand tons per year or 7.8%.

Claims (2)

1. USSR author's certificate ff 6 47023, cl. B 21 B 1/22, 197. 2. For Japan No. 5 4-61088, cl. In 21 In 1/02, pub. 19793- USSR Copyright Certificate No., cl. B 01 B 1/36, 1975. Wzj 2 ////////////////// Fy 5