JPS63137501A - Method for edging slab press - Google Patents

Abstract

PURPOSE:To improve the yield of a product by variously combining the edging reduction amount and rolling down length per pass at the front and rear ends of a slab thereby performing the front and rear ends of the slab to a tongue or fishtail shape. CONSTITUTION:The front and rear ends of the slab 3 are pressed at the smallest possible number of passes or at the rolling reduction per pass set smaller than the rolling reduction in the previous pass at the time of edging the front and rear ends of the slab 3 at the prescribed reduction by the parallel parts and tapered parts of dies 6. The front and rear ends of the slab are preformed to the tongue shape or fishtail shape by this method, by which the yield of the product is improved.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a press that can selectively preform a tongue or a fishtail on the leading and trailing ends of a slab when width-reducing a slab using a press. This relates to a method for reducing the width of a slab.

[Prior Art] In order to improve the product yield when horizontally rolling a slab after width reduction, the same inventor as the present inventor proposed a method of preforming the leading and trailing ends of the slab into a nearly rectangular shape. (See Japanese Patent Application No. 81-2807).

The principle of this method is that when the front and rear ends of the slab are preformed using a press, the planar shape of the front and rear ends of the slab changes by 1.
It depends on either the width reduction amount per turn or the reduction amount (contact length of the mold). In other words, if the width reduction amount or reduction amount per turn is set small, the reduction action will not penetrate to the center of the slab. , the range of plastic deformation of the slab (range of material flow) is limited to a range relatively close to the mold, and as a result, fishtails tend to form at the leading and trailing ends, and conversely, the amount of width reduction This method is based on the new finding that if the amount of rolling reduction is set to a large value, the rolling action permeates into the center of the slab, which tends to form tongues at the leading and trailing ends of the slab. When this principle is applied to slabs with different width dimensions, the leading and trailing ends of the slab can be preformed into a nearly rectangular shape regardless of the width dimension, improving product yield.

[Problems to be Solved by the Invention] However, in addition to preforming the front and rear ends of the slab into a nearly rectangular shape, it is often desired to form a fishtail or tongue. In other words, in a rolling line that produces strips from slabs, width reduction and horizontal rolling are repeatedly performed. For example, if a fishtail occurs for some reason during horizontal rolling in the intermediate process, If the width-reducing press in the next process can form a tongue that offsets this fishtail, a slab with nearly rectangular leading and trailing ends can be supplied to the horizontal rolling machine in the next process. Therefore, contrary to the above, a width reduction press that receives a slab with a tongue formed therein is advantageous in the next rolling process if a fishtail can be formed to offset the tongue.

Furthermore, the horizontal rolling mill in the next process has a tendency to produce fishtails or tongues for some reason (
If it is known in advance that the slab will have the above-mentioned characteristics, it is recommended to form a tongue or fishtail in advance at the tip and rear end of the slab to offset the above-mentioned characteristics during width reduction on the upstream side of the horizontal rolling mill. This is very advantageous for horizontal rolling in the next step.

[Means for Solving the Problems] In view of the above-mentioned problems, the present invention forms a fishtail or tongue at the tip or rear end of the slab, or plastically deforms the slab so as to offset the fishtail or tongue. This method was developed in order to provide a method for reducing the width of a slab using a press that can be obtained using a press, and the method involves adjusting the amount of reduction and setting by appropriately selecting the lengths of the parts where the parallel part of the mold and the tapered part contact the slab, respectively. A width rolling method in which the front and rear ends of the slab are pressed with a sufficiently large amount of rolling and as few times as possible, and a width rolling method in which the rolling amount per round or at least one of the rolling amount is Select one of the width rolling methods, which are set to be smaller than the rolling reduction amount and press the front and rear ends of the slab until the total rolling amount reaches the rolling amount in the method described above, and then press the front and rear ends of the slab. The part is preformed.

[Effect] When width reduction is repeated in small increments by setting a small amount of width reduction each time, or when width reduction is performed with a small amount of reduction, plastic deformation occurs inside the slab near the mold, causing deformation at the tip and back of the slab. The ends extend into fillet tails. In addition, if you set a large amount of width reduction each time and perform width reduction in a small number of times, or set a large amount of width reduction and perform width reduction, plastic deformation will seep into the center of the slab, causing the front and rear ends of the slab to form a tongue-like shape. It extends to. Therefore, by selecting the above method, it is possible to form an arbitrary shape at the leading and trailing ends of the slab.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure shows the first embodiment of the present invention, and in the figure, l is a slab, 2 is the tip of the slab, 3 is the center of the slab, 4.4 is a mold for pressing the slab l, and 5 and 6 are respectively These are the parallel part and the tapered part of the mold.
The specified width reduction amount (AW on one side) is achieved by the width reduction operation twice.
Shows the state where the width has been lowered by the width. Reduction amount (mold contact length) L
is set sufficiently large to span both the parallel portion 5 and the tapered portion 6. Under this width reduction condition, the width reduction effect permeates to the center of the slab, so the slab tip 2 extends forward over the entire width, forming the tongue 7.

A second embodiment of the invention is shown in FIG. In this example, the width of the slab tip 2 is repeatedly rolled down in small steps multiple times, and the total amount of reduction and the amount of reduction are the same as in the first embodiment. Under this rolling condition, the plastic deformation inside the slab 1 is limited to a small area near the dies 4, 4, so the slab tip 2 extends forward along the parallel parts 5, 5 of the dies, and the fishtail 8 , 8 are formed.

A third embodiment of the invention is shown in FIG. In this example, the tapered part 6 of the mold is used to reduce the width of the slab tip 2 by the same amount in one width reduction as in the first embodiment, but the reduction amount L1 is smaller than in the first embodiment. is set (L
+ <L).

Under this rolling reduction condition, since the rolling reduction amount L1 is small, the plastic deformation does not permeate to the center of the slab, and the slab tip 2 extends forward along the tapered part 8, resulting in fishtails 8a, 8a.
is formed.

A fourth embodiment of the invention is shown in FIG. In this example, the width of the slab tip 2 is reduced using the same amount of reduction and the same number of reductions as in the second embodiment using the tapered part starting from the boundary line 9 between the parallel part 5 of the mold and the tapered part 6, but the amount of reduction is are set to the same dimensions as in the third embodiment. Under this rolling condition, the plastic deformation inside the slab 2 is limited to the narrowest area near the molds 4, 4 compared to each example, so that it extends forward along the parallel part 5.5 of the mold, Steep fishtails 8b, 8b with the largest elongation amount compared to the second and third embodiments are formed.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

C Effects of the Invention] As described above, the present invention exhibits the following excellent effects.

(1) Since the width reduction is carried out by combining various width reduction amounts and reduction amounts per one time, the front and rear ends of the slab can be preformed into a tongue shape or a fishtail shape (overcompensated reduction forming).

G] As a result of paragraph (1), if the front and rear ends of the slab are preformed to match the characteristics (or habits) of the horizontal rolling mill installed in the downstream or upstream process of the width reduction press, the rolled product It becomes possible to horizontally roll the end portion into a rectangular shape, improving product yield.

[Brief explanation of the drawing]

1 to 4 respectively show the first, second, and third embodiments of the present invention.
Embodiments 3 and 4 are shown, in which Fig. 1 shows the slab tip and rear end in a tongue shape, and Figs. 2, 3, and 4 show the slab tip and rear end in a fishtail shape. FIG. In the figure, ■ indicates the slab, 2 indicates the tip of the slab, 4 indicates the mold, 7 indicates the tongue, and 8.8a and 8b indicate the fishtail.

Claims (1)

[Claims] 1) Appropriately select the length of the part where the parallel part of the mold and the tapered part contact the slab, and set the rolling length and the rolling amount per roll to be sufficiently large and as few times as possible to roll the front and rear ends of the slab. A width reduction method for pressing, and at least one of the amount of reduction per one time or the amount of reduction per time is set smaller than the amount of reduction per time or the length of reduction in the method, so that the total amount of reduction is equal to the amount of reduction in the method. A method for reducing the width of a slab using a press, characterized in that the front and rear ends of the slab are preformed by selecting one of the width reduction methods of pressing the front and rear ends of the slab until they reach the desired width.