JPS6240904A - Rolling method for steel bar - Google Patents

Abstract

PURPOSE:To decrease the kind of rolls and accessories for rolling a steel bar and to eliminate the need for rearranging and exchanging the rolls by using rolling rolls each having a rhombic shape caliber of which the vertical angle is a specific angle to constitute alternate horizontal and vertical pass lines so that the roll gaps are made successively smaller. CONSTITUTION:The alternate horizontal and vertical pass lines are constituted of the rolling roll 2 set each having the rhombic caliber 1 of which the vertical angle is 135 deg. to successively decrease the roll gaps S in the progress direction of the pass lines. A rolling material is rolled to an irregular octagonal section and is gradually decreased in the sectional area. The material is made into the steel bar having a prescribed shape and size in the final pass. The fewer kinds of the rolls and accessories are required and the need for rearranging and exchanging the rolls is eliminated except when the calibers are worn. Galling flaws are decreased without the need for a twister and the quality of the steel bar is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a rolling method for rolling steel material to obtain long steel bars, wire rods, and the like.

(Conventional technology) In general, in rolling steel bars, wire rods, and other long steel products, rolling methods such as the mellow method, the rhombus method, and the box method are adopted depending on the type of caliber provided in the rolling rolls and the pass schedule. has been done.

As the rolls used in each of these methods, rolling rolls having holes of successively smaller dimensions in the pass line direction are prepared and used.

(Problem to be solved by the invention) For this reason, in the conventional method, it is necessary to prepare many types of rolling rolls and accessories such as entrance guides, exit guides, etc., and their storage and management are complicated and storage space is limited. In addition to being bulky, it was necessary to replace the rolls and accessories each time the size changed, which was an obstacle to improving productivity, especially in high-mix, low-volume production lines. In addition, in rolling methods with pass schedules such as square-box or square-oval, 4
A twister was required for twisting the device by 5 degrees, which was not desirable in terms of product quality and equipment installation space.

This invention solves the above-mentioned conventional problems, and aims to provide a method for rolling long steel that requires fewer types of rolling rolls and accessories, and that can perform no-twist rolling.

(Means for Solving the Problems) However, in the method for rolling a long steel of the present invention, a plurality of sets of rolling rolls having holes of the same shape are arranged horizontally and vertically alternately along a pass line, and horizontally and vertically In each direction, the roll gap is set smaller in the pass line advancing direction, and the steel material is rolled with the above-mentioned rolling rolls to form an intermediate product, which is then rolled with a roll having a finishing hole to obtain a long steel. This is a long steel rolling method characterized by:

The long steel rolling method of the present invention can be consistently applied to the entire process of rolling mill rows from the rough row through the intermediate row to a part of the finishing row (excluding roll rows having finishing holes). The conventional hole method may be used in combination with the entrance side of the steel billet or part of each row.

The hole shape in this invention is easy to process,
Moreover, it is preferable to use a diamond-shaped hole because the difference in peripheral speed of the hole is small, so the life of the hole is long and there is less occurrence of wrinkles in the material. Further, when a diamond-shaped hole shape with an apex angle of 135° is used, the +41+ cross-sectional shape can be uniformly deformed all around by repeating flat nonagons and regular octagons, which is particularly preferable in terms of material homogenization.

(Function) In the rolling method of this invention, the steel +4 is rolled by rolling rolls arranged horizontally and vertically alternately, so no twister is required. In addition, since multiple sets of rolling rolls with the same hole shape are used with the roll gap set smaller in each horizontal and vertical direction in the pass line advancing direction, rolling rolls, entrance guides, exit guides, etc. f
tfi products require only a small number of types, and the area reduction rate can be easily selected by simply adjusting the roll gap, and the optimum rolling conditions can be easily set by changing the area reduction rate distribution in the pass line. can.

(Example) An embodiment of the present invention will be explained below with reference to FIG.

Fig. 1 shows a pass schedule diagram in which rolling rolls 2 of the same size and having a diamond-shaped hole 1 with an apex angle of 135° are arranged horizontally and vertically alternately as shown in Fig. 1 (a) to (f). Six sets of rolling rolls 4 of the same size and having diamond-shaped grooves 3 with a vertical angle of 135° are arranged in the same figure ((1) to (h)).
They are used by arranging two sets alternately horizontally and vertically as shown in the figure. As shown in (a), (C), and (e) of the same figure, the gap S between the horizontal rolls is set gradually smaller in the direction of pass line progression, and similarly as shown in (b), (d), and (f) of the same figure. In this way, the gap t between the vertical rolls is also set gradually smaller in the pass line advancing direction.

When the heated steel billet 5 is rolled according to the pass schedule configured as described above, the steel billet is elongated while being alternately deformed into a flat nonagonal shape and a regular octagonal shape, and an intermediate product 6 having a small cross-sectional area is obtained. This intermediate product is produced by a finishing row mill equipped with rolling rolls having conventional finishing hole shapes such as round, square, oval, and without grooves, depending on the final finished shape of the long steel such as round steel, flat steel, and square steel. Rolling to obtain long steel products.

As mentioned above, there are few types of rolling rolls and groove types (
In this embodiment, there are two types), and since the hole shapes have the same apex angle, the number of types of accessories such as entrance guides and exit guides can be reduced. Further, the area reduction rate can be easily selected only by adjusting the roll gap, and the distribution of the area reduction rate in the pass line can be changed freely, making it easy to set the optimum rolling conditions.

The present invention is not limited to the above-mentioned embodiments. For example, the hole shape 1.3 may have a shape other than a rhombus, such as an oval, and the type of the hole shape may be other than two types (1.3).
type is particularly preferable).

(Effects of the Invention) As explained above, according to the present invention, the types of rolling rolls and accessories are greatly reduced compared to the conventional ones, and the storage and management of these rolling rolls, etc. is facilitated, and storage space is also reduced. Not only is it small, but it also eliminates the need for frequent roll changes and replacement of accessories, which greatly contributes to improving the productivity of long steel production lines. Furthermore, since there is no need to use a twister, the installation space for the device can be reduced, and the quality of the bar can be improved by reducing scratches.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(h) are path schedule diagrams showing one embodiment of the present invention. 1... Groove shape, 2... Roll for rolling, 3... Groove shape,
4...Roll for rolling, 6...Intermediate product.

Claims (1)

[Claims] 1. A plurality of sets of rolling rolls having holes of the same shape,
The rolling rolls are arranged horizontally and vertically alternately along the pass line, and the roll gaps in each of the horizontal and vertical directions are set to become smaller in the direction of progress of the pass line, and the steel material is rolled by the above-mentioned rolling rolls to obtain an intermediate product. A method for rolling a long steel, characterized in that the long steel is obtained by rolling with a roll having a finishing hole. 2. The long steel rolling method according to claim 1, wherein the hole shape is rhombic. 3. The long steel rolling method according to claim 2, wherein the apex angle of the rhombus is 135°.