JPS61242701A - Thickness rolling down method for slab - Google Patents

Abstract

PURPOSE:To decrease the dimensional fluctuation in the transverse direction of a slab by determining the coefft. of friction between anvils and the slab in such a manner that the coefft. of friction is smaller nearer the ends of the slab in the transverse direction thereof than in the central part, thereby allowing the slab ends to elongate in the longitudinal direction. CONSTITUTION:The slab S is rolled down by a press 1 while the slab is conveyed in an arrow A direction. The anvils 2, 3 are disposed above and below the slab S. The anvils 2, 3 are pressed to the top and bottom surfaces of the slab S to roll down the slab S from the thickness H0 to H1 while a lubricating agent P is supplied between the slab S and the anvils 2, 3. The slab is rolled down while the lubricating agent P is supplied at the rate increasing toward the transverse ends of the slab than in the central part. Plural pieces of pipes 6 are arrayed at intervals to the inlet side of the slab S to the press 1 in the transverse direction in order to supply the lubricating agent in the above-mentioned manner. The dimensional fluctuation in the transverse direction is thus improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of reducing a slab in the thickness direction using a press.

[Prior Art] For example, when a slab manufactured by a continuous casting method or a long slab to be transported to a rolling process is reduced in thickness by a press, the anvil of the press is passed in the width direction of the slab, The anvil is pressed against the slab, and the slab is reduced in thickness by the width of the anvil in -times of operation, and this is repeated in the longitudinal direction of the slab to reduce the entire slab.

[Problems to be Solved by the Invention] However, although rolling by a press allows for a large rolling reduction, unlike rolling, continuous rolling cannot be achieved and the rolling must be intermittent. Therefore, although the thickness can be made uniform, as shown in Fig. 7, the rolled portion bulges in the width direction, the width W of the slab S fluctuates in the length direction, and the width edges of the slab S become wavy. The problem is that it becomes.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for reducing the thickness of a slab, which can reduce fluctuations in the width of the slab.

[Means for Solving the Problems] The present invention provides a method of passing a press anvil in the width direction of the slab and pressing the anvil against the slab to press down the slab in the thickness direction. During this process, a larger amount of lubricant is supplied to the widthwise ends of the slab than to the center, and the coefficient of friction between the slab and the anvil is made smaller as the widthwise ends become smaller.

[Function] By supplying a larger amount of lubricant to the edges of the plate width than to the center, the coefficient of friction μ between the slab and anvil during pressing is distributed such that it becomes smaller toward the edges of the plate. In this state,
When the plate is rolled down with an anvil, the ends of the plate elongate well in the length direction, and the amount of elongation is equal to that of the center. Therefore, the bulge in the width direction is reduced, and fluctuations in board width are suppressed.

[Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a situation where a slab S being conveyed in the direction of the arrow is being rolled down by a press l.

Reference numerals 2.3 in the figure indicate anvils disposed above and below the slab S, and these anvils 2.3 extend in the width direction of the slab S. Then, while supplying lubricant P between the slab S and the anvil 2.3, the anvil 2.3 is pressed against the upper and lower surfaces of the slab S by the hydraulic cylinder 4.5, so that the slab S has a thickness of H0. from H
The pressure is reduced to 1.

What is important here is that the amount of lubricant P supplied is varied in the plate width direction. That is, as shown in FIG. 2, rolling is performed while supplying lubricant to the tapeworm from the center toward the ends in the width direction. By doing this, as shown in FIG. 3, the friction coefficient μ is distributed such that it is large at the center and becomes smaller toward the ends of the plate. Therefore, by rolling down in this state, the end portion of the plate can be stretched well in the length direction.

Let's compare this point with the conventional method. In the conventional method, the fourth
As shown in the figure, the elongation of the material when pressed decreased toward the ends in the width direction, but in the method of the present invention, the elongation of the material at the ends in the length direction becomes smaller due to the distribution of the friction coefficient as described above. This makes it easier to stretch, as shown in Figure 5.
Elongation is equalized across the width. Therefore, by stretching evenly, bulge in the width direction can be suppressed.

FIG. 6 shows variations in sheet width when rolling is performed by the conventional method and when rolling is performed by the method of the present invention.

As is clear from this figure, according to the present invention, variations in board width are reduced compared to the conventional method. This phenomenon is particularly noticeable when the amount of reduction is large.

Note that, as described above, a plurality of vibrators for supplying the lubricant P are arranged at intervals in the width direction on the entry side of the slab S into the press L. This is the same for both the upper and lower sides (the lower side is not shown).

[Effects of the Invention] According to the present invention, since the amount of lubricant supplied between the slab and the anvil is increased at the edge of the plate width than at the center, the coefficient of friction between the slab and the anvil during pressing is reduced. The edge of the plate becomes smaller, and the edge of the plate extends well in the length direction. Then, the amount of elongation at the end portions and the amount of elongation at the center portion become equal, and the bulge in the width direction becomes smaller. Therefore, despite intermittent rolling reduction, the effect of reducing fluctuations in sheet width can be obtained.

[Brief explanation of drawings]

1 to 3 are diagrams for explaining one embodiment of the present invention, and FIG. 1 is a perspective view showing a situation in which a slab is being rolled down;
Figure 2 shows the distribution pattern of the lubricant applied in the width direction of the plate, Figure 3 shows the distribution of the coefficient of friction in the width direction of the plate, and Figure 4 shows the elongation distribution when rolled by the conventional method. figure,
Figure 5 is a diagram showing the elongation distribution when rolled by the method of the present invention, and Figure 6 is a diagram comparing the width variation when rolled by the conventional method and the width variation when rolled by the method of the present invention. The figure shown in FIG. 7 is a plan view of a slab shown for explaining the conventional problems. S...Slab, P...Lubricant, 1...
...Press, 2.3...Anvil, 6...
・Pipe for lubricant supply. Figure 4 Figure 5 Figure 7 Procedural amendment (voluntary)

Claims (1)

[Claims] In a method in which a press anvil is passed in the width direction of the slab and the slab is rolled down in the thickness direction by pressing the anvil against the slab, the coefficient of friction between the anvil and the slab is determined by A method for reducing the thickness of a slab, which is characterized by reducing the thickness of a slab by making it smaller than the central part.