JP2687611B2 - Width reduction pressing method and press die - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a width reduction pressing method and a press die, in which width reduction due to necking occurring at the front and rear ends of a slab does not occur. is there.

[Prior Art] One of the width reduction methods of a slab is a width reduction method by a press. As shown in FIG. 4, a pair of molds 1 and 1 are arranged on both sides of the slab S in the width direction, and the slab S The molds 1, 1 are moved toward the downstream in the line direction in accordance with the flow in the line direction, and the molds 1, 1 are brought close to each other to perform width reduction.

As shown in FIGS. 4 and 5, the metal molds 1, 1 used for such a width reduction press have a parallel portion 2 formed downstream of the slab S in the line direction and are continuous with the parallel portion 2. And the inclined portion 3 is formed (Japanese Patent Application Laid-Open No. 63-273536, Japanese Patent Application Laid-Open No. 63-252634, etc.).

In the case of performing the width reduction by the molds 1 and 1, first, the tip of the slab S is positioned in the middle of the parallel portion 2 and the first width reduction is performed, and then, as shown in FIG. Then, the slab S is fed in the line direction, and the end of the parallel portion 2 is positioned in the middle of the slope formed by the inclined portion 3 of the mold 1 under the first width reduction, and the second width reduction is performed. In the same manner, the third and subsequent width reductions are performed.

[Problems to be Solved by the Invention] However, when the second width reduction is performed after the first width reduction, as shown in FIG. The slab S is deformed so as to bulge outward at the intersection with the part 3, and as a result, as shown in FIG. 5 (b), the tip of the slab S bends outward, causing so-called necking N. .

For this reason, when the slab S after width reduction is rolled in the rolling line of the next step, there is a problem that the product is reduced in width by a considerable length.

Therefore, since such a necking phenomenon occurs at the front and rear ends where the restraining force of the slab S is small and the tip is width-reduced by the parallel portion 2 of the mold 1, the tip of the slab S is preformed into a taper shape. It is possible to do it.

However, if the tip end of the slab S is positioned on the inclined portion 3 of the mold 1 and the width of the slab S is reduced, the slab S escapes rearward, which makes preforming difficult.

The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide a width reduction pressing method and a press die that can perform width reduction without causing necking in a slab.

[Means for Solving the Problems] In order to solve the problems of the above-described conventional technology, the width reduction pressing method of the present invention is such that, when the slab is width-reduced, the end of the slab is inclined with a small inclination part of the mold and a large inclination. It is characterized in that after the width is reduced by the section, the width is reduced by the parallel section and the inclined section of the mold.

Further, the press die of the present invention is characterized in that a small sloping portion and a large sloping portion are sequentially formed on at least one of the parallel portions of the press die for width reducing the slab.

[Operation] According to this width reduction pressing method, the end (front end or rear end) of the slab is divided into a small inclined part having an inclination smaller than that of the conventional mold and a large inclined part having the same inclination as the conventional one. After that, the mold part is made to be width-reduced, and thereafter, the parallel part and the inclined part as in the conventional case (this inclined part only needs to have at least a large inclined part, and the small inclined part and the large inclined part are continuously connected. The width of the slab is assumed to be curved parallel to the outside, and it is assumed that the tip of the slab bends outward due to the width reduction due to the large slope. With a small inclined portion, width reduction is performed to prevent necking and prevent rearward escape of the slab.

Further, according to the press die of the present invention, the small sloping portion and the large sloping portion are formed in order on at least one of the parallel portions, whereby the rear escape of the slab during the width reduction of the end portion of the slab. The end portion can be preliminarily formed into a tapered shape without causing the occurrence of necking, and necking and width reduction can be prevented.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 and 2 are a schematic perspective view and a detailed view of one embodiment of the width reduction press die of the present invention.

As shown in FIG. 1, the die 10 of this width reduction press has
A pair of parallel portions 11 are arranged on both sides in the width direction of the slab S and are parallel to the line direction. The parallel portion 11 is formed on the downstream side of the line direction. The small inclined portion 12 and the large inclined portion 13 are sequentially formed on the parallel portion. It is composed of three molding parts 11, 12, and 13.

Details of these three molding parts are shown in FIGS. 2 (a) and 2 (b).
As shown in FIG. 5, the small inclined portion 12 has an inclination angle θ1 (<< of the inclination angle θ (see FIG. 5A) of the inclination portion of the conventional mold.
θ) is, for example, 10 degrees or less, and the large inclined portion 13 has an inclination angle θ2 (= θ, which is the same as the inclination angle θ of the inclined portion of the conventional mold).
θ1 <θ2), for example, 10 to 15 degrees, usually 12 degrees or 13 degrees.

Therefore, the shape of the slab S when width-reduced by such a mold 10 is, as shown in FIG.
A small taper portion and a large inclined portion 13 corresponding to the inclination angle θ1 of the small inclined portion 12 continuously to the parallel portion of the tip corresponding to
A large taper portion corresponding to the inclination angle θ2 of is formed.

Next, the function of the die 10 of the width reduction press and the width reduction press method will be described with reference to FIG.

First, at the start of the width reduction press, the tip of the slab S is positioned on the small inclined portion 12 of the mold 10 to perform width reduction (see FIG. 3 (a)).

Then, the tip portion of the slab S is pressed into a tapered shape in which the tip portion becomes thin according to the inclination angle θ1 of the small inclined portion 12 of the die 10, and the large inclined portion of the die 10 is continuously formed. 13
The taper is pressed into a large angle in accordance with the inclination angle θ2 of.

At the time of the first press, the tip of the slab S is pressed by the small inclined portion 12 having a smaller inclination angle than the large inclined portion 13, so that there is no rear end clearance and the width is reduced by a predetermined amount. You can

Next, the slab S is fed in the line direction, and the width reduction is performed so that, for example, the tip end portion is located in the parallel portion 11 of the mold 10.

Then, since the width reduction is performed with the tip of the slab S tapering, the slab S rises to the outside by the press with the large sloping portion 13 as shown in FIGS. 3B and 3C. Even if it deforms like this, it stops in a parallel state, and necking does not occur.

After that, the slab S is fed in the line direction, and the width reduction is repeated to perform a predetermined width reduction press.

Then, as for the rear end of the slab S, as in the case of the front end, after the rear end is positioned on the small inclined portion 12 and the large inclined portion 13 of the mold 10, preforming (pressing) is performed, If the normal width reduction is performed, necking can be prevented, and width reduction can be prevented even in the product after rolling in the next step.

Incidentally, at the time of the second width reduction, as shown in FIG. 3 (b), the mold 10 composed of the parallel portion 11 and the large inclined portion 13 may be used as in the conventional case, The mold 10 having the small inclined portion 12 shown in FIGS. 1 and 2 may be used as it is.

According to the die 10 of such a width reduction press, the small inclined portion
With 12, the front and rear end portions of the slab S can be preformed, whereby necking can be prevented from occurring, and rearward escape can also be prevented.

Further, according to such a width reduction pressing method, the mold 10
Since the front and rear ends of the slab S are pressed in advance by the small inclined portion 12 and the large inclined portion 13 of the slab S, normal pressing is performed by the parallel portion 1 and the inclined portion 13, so that necking can be prevented. It is also possible to prevent backward escape.

Therefore, even when the product is rolled after the width reduction, the width of the product does not drop, and there is no waste.

In the above embodiment, the small inclined portion and the large inclined portion are formed on only one side of the mold, but the small inclined portion and the large inclined portion may be formed on both sides of the parallel portion. The front and rear ends can be efficiently reduced in width.

Needless to say, each component may be changed without departing from the scope of the present invention.

[Effects of the Invention] As described above in detail with reference to the embodiments, according to the width reduction pressing method of the present invention, the width of the end portion of the slab is reduced by the small inclined portion and the large inclined portion of the mold. ,After this,
Since the width reduction is made between the parallel portion and the inclined portion, it is assumed that the tip of the slab bends outward due to the width reduction caused by the large inclination portion, and in this case, the slab is slightly inclined so that it is just parallel. It is possible to perform width reduction at the portion, thereby preventing necking and preventing rearward escape of the slab.

Further, according to the press die of the present invention, the small sloping portion and the large sloping portion are formed in order on at least one of the parallel portions, so that when the width of the slab end is reduced, the slab rearward escapes. The end portion can be preliminarily formed into a tapered shape without inviting, necking can be prevented, and width reduction can be prevented.

[Brief description of the drawings]

1 and 2 are a schematic perspective view and a detailed view of one embodiment of the width reduction press die of the present invention. FIG. 3 is a schematic process drawing according to an embodiment of the width reduction pressing method of the present invention. FIG. 4 and FIG. 5 are a schematic perspective view of a mold of a conventional width reduction press and an explanatory view of a slab. 10: Mold for width reduction press, 11: Parallel part, 12: Small inclined part, 13:
Large slope, S: Slab.

Claims (2)

(57) [Claims] 1. When the slab is width-reduced, the end portion of the slab is width-reduced by the small inclined part and the large inclined part of the mold, and then the width is reduced by the parallel part and the inclined part of the mold. A width reduction pressing method characterized by the above. 2. A press die, wherein a small inclined portion and a large inclined portion are sequentially formed on at least one of parallel portions of a press die for width-reducing a slab.