JPS60203302A - Method and device for rolling hot slab in width direction by press - Google Patents

Abstract

PURPOSE:To reduce the formation of tongue at the rear end of a slab by using a pair of anvils having each a slant part at the inlet side, a parallel part at the intermediate part, and a deep cut stepped part at the outlet side in the advancing direction of a hot slab and subjecting the hot slab to heavy rolling reduction in its width direction. CONSTITUTION:A press device is provided with a pair of anvils 3, each of which has a rolling reduction face consisting of a slant part AB at the inlet side, a parallel part BC at the intermediate part, and a deeply cut stepped part CDE at the outlet side in the advancing direction R of a hot slab 4. Next, the slab 4 is continuously pressed from its front end by utilizing the rolling reduction faces of the parts AB, BC, while periodically vibrating the anvils 3 by a prescribed rolling-reduction. When the width rolling reduction reaches the nonstationary deformation region W0 of the rear end of slab 4, the slab 4 is advanced to abut its rear end to the stepped part 6 of anvil 3, and the region W0 is subjected to rolling reduction to the prescribed rolling reduction. In this way, the tongue formation at the rear end of slab, can be reduced without lowering its high productivity with respect to the width rolling reduction of hot slab.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a technology for width reduction of hot slabs. The present invention relates to a method and apparatus for significantly reducing slabs.

Initially, in hot strip rolling, the raw material was a slab that had been subjected to blooming and then reheated in a heating furnace, but due to demands for energy saving and process shortening, recently it has been rolled using continuous rolling. It is a well-known fact that pulcess, which produces slabs directly from the edge, has become mainstream. However, in recent years, in order to further improve the efficiency of energy and manufacturing processes, synchronization of continuous casting and hot strip mills has been introduced. In order to achieve this, integration of casting width in continuous casting and introduction of large slab reduction technology are being considered.

(Prior art) Among these methods, VH rolling is usually used to reduce the width of a slab by repeatedly performing edging (V) rolling and horizontal (H) rolling using a hard rolling mill. There is.

First, when the slab is rolled 'fr-2, dogbone deformation in which the plate thickness at the width end of the slab swells, and fishtail deformation in which the width end of the slab protrudes in the longitudinal direction of the slab at the front and rear ends of the slab are likely to occur. If a slab with this dogbone deformation is subsequently subjected to H rolling, a significant width expansion will occur, canceling out the amount of width reduction due to VEE rolling.
The processing energy required for rolling will be wasted. Further, when the width reduction source is large, multi-pass rolling is required, which impedes production efficiency and causes large energy loss, and the fishtail increases in proportion to the full width reduction amount, resulting in a decrease in yield.

Furthermore, in V-H rolling, a large tensile stress is generated at the center of the sheet width during H rolling, so there is a risk that internal defects such as cracks and surface defects may occur.

As a width reduction method aimed at eliminating such drawbacks, there is a large reduction technique using a continuous press.

When width reduction is performed using a press using this method, the cross section of the slab is uniformly deformed, and severe dogbone deformation does not occur even with a large width reduction source. The quantity is also small. but,
If the width reduction press is performed continuously from the front end to the rear end, a relatively large tongue (tongue shape) is produced at the rear end of the slab, which has the disadvantage of causing a decrease in yield.

(Object of the Invention) The present invention solves the drawbacks of the continuous press technology and provides a heat treatment method that can significantly reduce the slab shape, especially tongue formation, without impairing high productivity. The object of the present invention is to provide a method and apparatus for significantly reducing intermediate slabs by pressing.

(The beginning of the idea) To achieve this objective, the inventors analyzed and studied the causes of tongue formation in the above-mentioned large reduction method, and found that when a continuous width reduction press is used to perform pongeeing from the tip of the slab,
We discovered that tongue deformation progresses from a certain length before the rear end of the slab, and as a result of further research into ways to prevent this tongue deformation, we found that the shape of the anvil of the width reduction press, especially the rear end of the slab. It was discovered that deformation of the tongue can be effectively prevented by making the shape of the rolling surface on which the width of the tongue is rolled down into a special electric shape, thereby completing the present invention.

(Structure of the Invention) That is, the gist of the present invention is to provide a pair of anvils having an inclined part on the entry side in the direction of movement of the hot slab, a parallel part in the middle, and a cut step part on the exit side. When pressing a hot slab into a predetermined width using an anvil, in the steady deformation region including the tip of the slab, the width reduction is performed continuously using the entrance inclined part and the parallel part of the anvil, and the width reduction is By pressing a hot slab, the slab is moved forward when it reaches an unsteady deformation region at the rear end of the slab, and the rear end of the slab is compressed to a predetermined width while being restrained by the notch step part of the anvil. Width reduction method, and width of a hot slab characterized by having a pair of anvils having an inclined part on the entry side in the direction of hot slab movement, a parallel part in the middle, and a cut step part on the exit side. Located in the rolling press device.

The present invention will be explained in detail below.

Continuous width reduction pressing on hot slabs is performed by basic operations as shown in FIG. That is, a pair of anvils 8
The rolling surface of # is inclined toward the entry side in the traveling direction (R) of the hot slab 4.
The vSl is configured to have parallel parts 2 at the intermediate and exit sides that follow this, and while these anvils 8 are periodically vibrated (amplitude 2a) under the width reduction amount ΔW, the entry side plate @lW is placed in the gap between them.
Slab 1 of width s is continuously (or intermittently) fed, and the slab is width-reduced to obtain slab f of exit side plate width Wf. In this case, one cycle of this continuous width-reduction press is as shown in Fig. 2. As shown in , the operation consists of k) slab rolling down, (b) anvil detachment, slab advancement, and (c) slab rolling down (Wp+ rolling down area).

When slab 4 is rolled down in width by such basic operation,
As mentioned above, a relatively large tongue is formed at the rear end of the slab.

By the way, it has been found that the tongue deformation progresses as shown in FIG. In the same figure, the anvil angle θ of the inclined part is 12
° Anvil 8 with amplitude 2a”60M.

This figure shows the deformation status of the rear end of the slab over time when it is operated under the condition of a width pressure of 1 inch ΔW = 800 mm. As can be seen from the figure, when the rear end of the slab 4 is near the rear end of the entry side slope of the anvil 8, the rear end of the slab 4 is in an unprocessed state and no tongue deformation occurs, but the slab 4 is in the advancing direction ( R), and the tongue deformation begins to occur when the width is lowered at the stage when the rear end has advanced forward by approximately half the width of the slab width from the rear end of the entry side slope of the anvil 8, and as it advances further, the tongue deformation gradually occurs. It is undergoing a growing process.

In consideration of the process of producing the tongue shape, the present invention provides a specific shape for the anvil. This point will be explained below.

FIG. 4 shows an example of an anvil shape according to the present invention, in which a pair of anvils 8 have an inclined part AB on the entry side in the traveling direction (R) of the hot slab 4, a parallel part BO in the middle, and a cut on the exit side. Step part ODE
It has a rolled-down surface with a shape consisting of an inclined part sAB and a parallel part BO.
is the rolling direction for forming a steady deformation region including the tip of the slab 4, and the cut step ODE is a rolling surface for rolling down only the rear end of the slab to form an unsteady deformation region. Note that the shape of the cut step is 11 d/ of the cut step CD in consideration of the above-mentioned tongue generation process.

The larger the value, the better, at least 1/of the minimum slab width.

It is desirable that it be at least a certain level.

In the process of reducing the slab width using a press device having such an anvil configuration, first, a press that vibrates periodically in accordance with the above-mentioned basic operation utilizes the reduction surface of the slope sAB and the parallel portion BO to reduce the width of the slab 4. Start width reduction from the tip.

Then, when the width reduction reaches a predetermined length from the rear end of the slab, for example, as shown in FIG. -H
Open the slab 4 to more than the initial width and move the slab forward so that the rear end of the slab touches the cut step 6,
Subsequently, the anvil 8 is rolled down all at once to a predetermined reduction amount, and the rear end of the slab is processed. Since the rear end surface of the slab is suppressed by the cut step 6, the slab 4 does not protrude rearward and no tongue is formed.

According to the method of the present invention, it is only necessary to move the slab 4 in one direction, and the movement is also carried out continuously, so that the formation of tongues can be suppressed and at the same time, the width reduction press time can be shortened.

Next, a sixth example of the continuous width reduction press apparatus according to the present invention will be described.
Shown in M. In the figure, the anvil 8 is arranged so as to be able to vibrate by a hydraulic cylinder 9 via an anvil fixing block 8 which is slidably provided in the window of the housing 10, and the anvil shape is as shown in FIG. (The advancing direction of the slab 4 is indicated by an arrow R in the figure.). Note that 7 is a pinch roller for conveying the slab.

Next, the operation of the present invention will be explained in detail, including slab conveyance control.

In Fig. 7, the slab 4 with the entrance side plate width W8 is indicated by the arrow R in the figure.
When the slab detector 21 detects the tip of the slab, the pinch roller 20 is lowered, and while tracking the slab by the pulse generator 22 connected to this pinch roller, the slab is conveyed in the direction of the slope AB of the anvil 8. And F4r constant II from the slab tip using the parallel part OD
Starting under IMIE, a steady deformation region is formed.

From the time when the rear end of the slab 4 is detected by the slab detector 21', the pinch roller 20' is lowered, and the rear end of the slab is tracked by the retard pulse generator 22' connected to this pinch roller. and move the rear end of the slab [4a from point B as shown by the two-dot chain line in the figure!
When reaching the position , that is, reaching the unsteady deformation region, the anvil 8tr is once widened to be larger than the initial width W8 of the slab, and then the slab 4 is moved to L by the pinch roller 201 until the rear end of the slab passes the 0 point. Move forward by 1x. Note that X may be approximately 10 to 505 m+, and is not particularly limited.

Thereafter, the anvil 8 is closed to such an extent that the DE portion of the cut step portion contacts the slab side surface 4b, and the slab 4 is moved back to bring the rear end surface 4a into contact with the OD portion of the cut step portion of the anvil 8. (see Figure 5), and then rolled down to a predetermined width. If the transfer by the pinch rollers 20' can be performed reliably, the rear end 4a of the slab is advanced by L,
- It may be rolled down to a predetermined width.

(Real pongee example) Using the continuous width reduction press shown in Figure 6, a board width of 1500 m1 + 11. Thickness 220mm, length 12000mm
Anvil angle #=1g', swing 11i1 g a
= h o o, frequency 2 grad/ (1) With 60 reductions, the constant part was continuously reduced from the tip to the width reduction cover ΔW = 800sm, and when about 800 degrees of unreduced area remained. Once the anvil was opened, the slab was moved with a bin roller so that the rear end of the slab was in contact with the cut step of the anvil, and then the rear end of the slab was rolled down at once. FIG. 8 shows the planar shape of the rear end of the slab after width reduction.

On the other hand, in the conventional method, when width reduction was carried out uniformly from the front end of the slab to the rear end, that is, without special treatment of the rear end of the slab as in this example, the rear end of the slab after width reduction was The shape was as shown in FIG.

As can be seen by comparing FIGS. 8 and 89, in the case of the present invention (FIG. 8), the crop is very short, there is very little tongue formation, and the shape of the slab rear end is good. On the other hand, in the case of the conventional method (FIG. 9), the p-tube of the beam is long and the rear end shape is such that tongue formation is difficult.

(Effects of the Invention) As detailed above, according to the present invention, while maintaining the high productivity of the conventional large reduction technology using a continuous press, the planar shape of the slab, especially the tongue at the rear end of the slab, can be improved. It is possible to obtain a product with an extremely good planar shape with significantly reduced generation, and the yield can be significantly improved.

[Brief explanation of the drawing]

Figure 1 is a diagram explaining the basic operation of a continuous width reduction press. Figures 2 (A) to (C) are explanatory diagrams showing the basic operation of Figure 1 over time. Figure 8 is the rear end of the slab. Figure 4 is a diagram showing an example of the shape of the anvil according to the present invention; Figure 6 is a diagram showing the width reduction of the unsteady deformation area at the rear end of the slab by the anvil according to the present invention. Fig. 6 is a side view showing an example of a continuous width reduction press device according to the present invention, and Fig. 7 is an explanation of the operation of the width reduction method of the present invention using the apparatus shown in Fig. 6. 8 and TS9 are diagrams showing the shape of the rear end of the slab after width reduction, with FIG. 8 showing the case according to the present invention and FIG. 9 showing the case according to the conventional method. 1... Inclined part 2... Parallel part 8... Anvil 4... Slab 6... Cut step part 7... Pinch roller -8...
Anvil fixing block 9...Hydraulic cylinder lO...
Housing 1, 2 o'...Pinch roller - 21, 2
1'...Slab detector 22.22'...Pulse generator. Patent applicant: Kawasaki Steel Corporation

Claims (1)

[Scope of Claims] L Using a pair of anvils having an inclined part on the entry side in the direction of movement of the hot slab, a parallel part in the middle, and a cut step part on the exit side,
When pressing a hot slab to a predetermined width, in the steady deformation area including the tip of the slab, the width reduction is performed continuously using the entrance inclined part and the parallel part of the anvil, and the width reduction is applied to the rear end of the slab. A method for width reduction by pressing a hot slab, characterized in that when the slab reaches an unsteady deformation region, the slab is advanced and the rear end of the slab is reduced to a predetermined width while being restrained by the cut step of the anvil. . (i) A press device for width reduction of a hot slab, characterized by comprising a pair of anvils having an inclined part on the entry side in the direction of travel of the hot slab, a parallel part in the middle, and a cut step part on the exit side.