KR0136193B1 - Rolling method - Google Patents

Abstract

According to the present invention, the rolled rolling method of manufacturing a hot rolled sheet material having various widths from a primary material of a constant width by increasing the width of the rolled material by performing horizontal rolling while crossing the rolls at a predetermined angle with the moving direction of the rolled material. It is intended to provide a purpose.

The present invention for achieving the above object is a method for rolling a material by a rolling mill including a plurality of upper rolls and lower rolls, cross-rolled by crossing the upper and lower rolls of the rolling mill to form an angle of 60 ° or less Then, the gist of the breadth rolling method using the cross roll which performs parallel horizontal rolling again is made into the summary.

Description

Widening rolling method using cross roll

1 is a schematic configuration diagram of a method of rolling width rolling by a cross roll according to the present invention,

(a) a plan view

(b) front view

Figure 2 is a schematic diagram showing the change in cross-sectional shape and the increase in width when rolling width by cross rolls according to the present invention

The present invention relates to a rim rolling method using a slab of a certain size to a hot rolled sheet material of various widths, and more particularly to a rim rolling method using a cross roll.

In general, the slab primary material having a constant width manufactured by a method such as continuous casting is made of hot rolled sheet material of various widths in the hot rolling process, which is the next process.

There are various methods for the variable width rolling method for manufacturing hot rolled sheet material having various dimensions, for example, as a typical method of the conventional method is as follows.

First, a method of reducing the width of the plate may be a method of rolling by using a vertical edge roll or by forging using a sizing press. The use of two vertical edge rolls or a sizing press may be used. In the case of the method of reducing the width of the plate, a so-called dog-bone is formed in which both ends of the width direction are inflated due to the concentration of deformation, and the dog-bone formed as described above is horizontally rolled by the following parallel rolls. As it goes through, it expands again in the width direction due to the spreading phenomenon, thereby reducing the efficiency of the variable width. In addition, when the thickness is thin, such as thin slab (thin slab) because the buckling (buckling) occurs rather than the width has a disadvantage that is difficult to apply to the thin slab.

Second, as a method of increasing the width of the plate as opposed to reducing the width, there are a rolling method using a release roll such as a groove roll and the like and a method of rolling the slab in the width direction like a thick plate rolling. The method of using the double groove roll is to increase the width by locally rolling the center portion of the slab in the width direction. There is also a disadvantage, and also parallelism for rolling the groove rolled material back to a uniform thickness is essential. In the case of the method of extending the width by rolling in the width direction, the length of the slab is determined by the plate width of the rolling mill, so it is not applicable to the long slab, and equipment for turning the slab vertically is required.

Accordingly, the present inventors conducted research and experiments to solve the problems and inefficiencies of the above-described conventional methods, and proposed the present invention based on the results. By increasing the width of the rolled material by performing the horizontal rolling in the cross-over state, to provide a hot rolled rolling method for producing a hot rolled sheet material having a variety of widths from a primary material of a constant width, an object thereof.

The present invention will be described below.

The present invention is a method of rolling a raw material by a rolling mill including a plurality of upper rolls and lower rolls, the upper roll and the lower roll of the rolling mill to cross the cross to form an angle of 60 ° or less, and then parallel horizontal rolling again It relates to a rolling process using a cross roll to perform.

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

In the present invention, as shown in FIG. 1A, the width of the material 3 is rolled horizontally while the upper roll 1 and the lower roll 2 cross each other at a predetermined angle θ. It is characterized by the production of hot rolled sheet material of various widths from the primary material of constant width by stretching. The effective roll diameter Re, which actually gives a reduction in rolling during such rolling rolls, becomes elliptical, as shown in FIG. 1 (b), where the radius of the roll is R and the crossing angle is θ. As described above, the short radius Rs is always equal to the radius R of the roll, but the long radius Rl is changed according to the crossing angle θ.

Rs = R, Rl = R / Sin (θ / 2)

Therefore, the rolling in the thickness direction during rolling by the cross roll is concentrated in the width direction central part of the raw material by the change of the effective roll diameter Re in the width direction determined by the crossing angle θ. According to the experimental results of the present invention, when the cross angle θ is 60 ° or more, the rolled plate-shaped cross section is not only asymmetrical but also has a bad rolling property such as a mailing relationship. Could know.

The variable width process according to the present invention takes place in two stages: the increase in width by cross rolls and the increase in width by rolling parallel rolls for thickness uniformity, which will be explained with reference to FIG.

As shown in FIG. 2, the primary rolled material 3, which has passed through the slab or the pass, forms a cross-sectional phenomenon as shown in (A) and passes through the cross rolls (1) and (2) to have a thin center. In order to maintain a constant volume, it is stretched in the longitudinal direction and the width direction to form a cross-sectional shape as shown in (B) so that the initial material width L becomes the cross-rolling material width L + ΔL '. At this time, the stretching in the longitudinal direction is constrained by the unrolled portion or the reduced amount of the pressed portion at both ends of the width direction of the raw material 3, so that the effect of the thickness rolling by the cross rolls 1 and 2 is mostly extended in the width direction. , That is, an increase in width. In this way, when the width of the material increased by the cross rolls (1) and (2) is rolled into a plate having a uniform thickness by the parallel rolls (4), a secondary width increase (Δℓ) occurs due to the spreading phenomenon and the material width is L + △. It will be ℓ.

That is, the width increase amount (Δℓ '+ Δℓ) by one rolling can be controlled by changing the effective rolling diameter Re of the pressing section by changing the rolling amount and the crossing angle (θ) of the cross roll. Hot rolled sheet material can be manufactured.

On the other hand, in the case of a reversible rolling mill capable of reversing the rotational direction of the upper roll (1) and the lower roll (2) while gradually reducing the cross angle, that is, by increasing the pressing area gradually by repeating cross rolling in a large way You can get an increase. Particularly, when the upper roll 1 and the lower roll 2 are parallel, that is, when the crossing angle is 0, conventional parallel roll work is possible. There are advantages to it.

Hereinafter, the present invention will be described in detail by way of examples.

EXAMPLE

The present invention uses a rolled roll having a diameter of 80 mm with a plasticine slab of 80 mm in width and 12 mm in thickness reduced to 1/20 of the slab of steel produced by ordinary continuous casting. The degree of increase in width was compared by rolling by the method using the cross roll of the conventional method and the parallel method using the parallel roll.

That is, the inventive method undergoes two stages of rolling in the widthwise center rolling by the cross rolls and the uniformity of the thickness by the parallel rolls. The thickness of the central portion (maximum pressure lower portion) was rolled to 8 mm, and this was secondarily rolled into a plate having a uniform thickness of 6 mm using a parallel roll.

In addition, as in the conventional method, the width increase amount when rolling with only parallel rolls was first rolled to slamm having the same size to 8 mm using parallel rolls, and then secondarily rolled to 6 mm.

After each rolling, the width was increased to calculate the spread ratio defined by the following equation and the results are shown in Table 1 below.

As shown in Table 1 above, in which the width spread between the rolls using only the cross rolls and the parallel rolls were compared, the width spread ratio of about 10.63% was obtained when the rolls were rolled using the cross rolls. It can be seen that the amount is 8.5 times larger than about 1.25% of the spreading ratio when rolling with only parallel rolls. When the width spreading ratio according to the present invention is converted into the case of an actual slab having a width of 1600 mm and a thickness of 240 mm, it corresponds to an increase in width of about 170 mm.

As described above, the present invention, unlike the conventional method of reducing the width using an edge roll or a sizing press, by rolling the slab of a certain size by the cross roll to increase the width, thereby facilitating the degree of width spread of the material In addition to the thin slab, it is also possible to vary the width, so there is an effect of manufacturing a hot rolled sheet material of various widths.

Claims (2)

In the method of rolling a raw material by a rolling mill including a plurality of upper rolls and lower rolls, the upper rolls and the lower rolls of the rolling mill are cross-rolled to form an angle of 60 ° or less, and then parallel horizontal rolling is performed again. Widening rolling method using the cross roll characterized in that. The rolling method according to claim 1, wherein the rolling mill is a reversible rolling mill capable of controlling the crossing angle of the upper roll and the lower roll, and the cross rolling and the parallel horizontal rolling are performed by the reversible rolling mill.