JPH0623401A - Rolling method for rough section for H-section steel - Google Patents

Abstract

(57) [Summary] [Structure] A rolling mill equipped with a caliber roll having two kinds of tapered projections is arranged on a roll cylinder, and a slab having grooves on both width end faces is sequentially passed through the rolling mill to roll the rolling mill. When forming the flange part by expanding the groove of the slab by each projection provided on the, the tip angle of the protrusion of the caliber roll that first passes the slab is smaller than the tip angle of the protrusion of the caliber roll that passes the slab later. Then, the rolling amount in the first rolling is set to 40 to 65% of the total rolling amount and rolling is performed. [Effect] With only a roll having two kinds of calibers, a wide beam blank having a flange portion having a desired width and cross-sectional area can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a slab obtained by continuous casting or the like having grooves on both sides of a single face, and rolling the slab with a rolling mill equipped with a caliber roll to produce a rough material for H-section steel. (Beam blank).

[0002]

2. Description of the Related Art A technique for producing a beam blank applicable to finish rolling of H-section steel by using a flat plate material such as a slab and rolling it with a plurality of rolling mills having caliber rolls is known. It is said to be advantageous for saving energy and omitting processes, and in recent years it tends to be used frequently,
For example, many proposals have been made so far, such as JP-A 61-927901 and JP-A 63-119902.

[0003]

By the way, by applying the above-mentioned conventional description, the height of the web is particularly high.
When manufacturing a so-called wide beam blank, it is difficult to match the protrusion of the caliber roll with the center of the width end face of the slab (the center in the thickness direction). The flange part of the obtained beam blank may be asymmetrical on the left and right, and stepwise rolling is required to expand the width end of the slab to a predetermined width. There was a disadvantage that the number of installed calibers was increased and the number of caliber rolls held had to be increased.

The object of the present invention is to obtain a beam blank having a large web height without causing shape deterioration, increasing the number of rolling mills installed, or increasing the number of rolls. A method for stably manufacturing a beam blank having a flange having a width and an area is proposed.

[0005]

According to the present invention, a rolling mill provided with a caliber roll having two kinds of tapered projections is arranged on a roll cylinder, and a slab having grooves on both width end faces is sequentially passed through the rolling mill. When forming the flange part by expanding the groove of the slab with each projection provided on the roll of the rolling mill, the tip angle of the projection of the caliber roll that first passes the slab is the tip angle of the projection of the caliber roll that passes the slab later. And a rolling amount of 40 to 65% of the total rolling amount in the initial rolling, and rolling is performed.

FIGS. 1a and 1b show the essential parts of a caliber roll suitable for carrying out the present invention. Reference numeral 1 in the figure shows the shape of the caliber through which the grooved slab is first passed (only the upper side of the upper and lower rolls is shown), and a tapered protrusion 1a is provided on the entire circumference of the roll cylinder. There is. Reference numeral 2 shows the shape of the caliber which is passed through the caliber and then passed through the grooved slab (only the upper side of the upper and lower rolls is shown), and the entire circumference of the roll cylinder is tapered. The protrusion 2a is provided, and these protrusions 1a and 2a have a relation of Θ ₁ <θ ₂ when the tip angle of the protrusion 1a is Θ ₁ and the tip angle of the protrusion 2a is Θ ₂ .

In a rolling mill equipped with rolls as shown in FIGS. 1a and 1b, a slab S having grooves 3 on both width end faces as shown in FIG. (Only the upper part is shown in Fig. 4), the caliber 1a of the caliber 1 is rolled into the groove 3 of the slab S so that the reduction amount is 40 to 65% of the total reduction amount. The groove 3 is pushed and expanded.

Then, the protrusion 2a of the caliber 2 is slab S
The groove 3 is further expanded in a state of being fitted to the groove 3 to form a flange portion as shown in FIG. 3, and the flange portion is further rolled to a desired width and area.

[0009]

When a slab having a groove on the width end face is used and a single blank caliber roll for rough rolling is used to roll a beam blank having a predetermined cross-sectional dimension, the centering property during rolling (the slab thickness direction When considering the difference between the center and the protrusion provided at the center of the roll cylinder of the caliber roll, the groove of the slab shall have a deeper groove depth and the relative angle with the protrusion provided at the center of the roll cylinder. Although it is necessary to reduce the difference, in such a case, the flange portion cannot have a predetermined width and area. On the other hand, if the tip angle of the projection provided at the center of the roll cylinder is increased, a flange portion having a predetermined width and area can be obtained with a single caliber roll, but the centering property is impaired.

According to the present invention, a rolling mill having a caliber roll having two kinds of tapered protrusions on the roll cylinder is arranged in the rolling line, and the tip angle Θ ₁ of the protrusion 1a of the caliber _{1 is set} to the caliber 2 of the caliber 2. It is made smaller than the one mainly focused on the centering, and the tip side angle Θ ₂ of the protrusion 2a is made larger on the rear side than that on the front side to form the flange part (width expansion at the width end of the slab. ), The flange with the desired width and area can be formed without causing shape deterioration or using multiple rolls even when rolling a beam blank with a high web height. Can be formed.

As for the caliber shape of the rolls arranged in the rolling mill, optimum ones may be examined and determined by rolling simulation and used.

The tip angle Θ ₁ of the protrusion 1a of the caliber ₁ is
From the viewpoint of improving the centering property, it is particularly preferable to set it in the range of 60 ° to 90 °, and the tip angle Θ ₂ of the protrusion 2a of the caliber 2 is set to improve the flange width extending property.
It is particularly preferable that the range is from ° to 150 °.

Regarding the grooves 3 formed at both width ends of the slab, it is better to make the depth of the groove deeper when the centering property is taken into consideration. On the other hand, when the width of the flange part is taken into consideration, the groove 3 is formed. Since it is better to reduce the area,
Considering both of these, l shown in FIG. 2 above.
Set ₁ , 1, ₂ and δ.

FIG. 4 shows a width of 1300 mm to 1500 mm and a thickness of 200 mm.
~ 220 mm slab (groove size: l ₁ = 110, l ₂ = 50, δ
= 60) and varying only the amount of reduction in rolling with caliber 1 and performing the subsequent Rigid-Plastic FEM analysis on the flared width of the flange under the same conditions for all subsequent rolling. Is shown.

From FIG. 4 shown above, it is clear that particularly when the rolling amount is reduced to 40 to 65% of the total reduction amount in the first rolling, the width of the flange portion is significantly widened in the subsequent rolling. Therefore, in the present invention, the rolling amount at the front stage side is set to 40 to 65% of the total rolling amount. The slab targeted by this invention is SS
41 to 50, SH41 to 50, etc. are used.

[0016]

[Example] Width: 1150 mm, thickness: 220 mm, and a slab (steel type: SS41) with trapezoidal grooves (l ₁ = 100 mm, l ₂ = 40 mm, δ = 50 mm, see FIG. 2) on both width end faces ) Is used in FIG.
Caliber rolls (Θ ₁ = 60 °, Θ ₂ = 14
The slab was rolled down in the widthwise direction using a rolling mill having a temperature of 0 °) and the width dimension and the area of increase of the flange portion were investigated.

The rolling amount in the first rolling is 120 mm (the distance between the protrusions of the caliber roll is 980 mm), and the rolling amount in the subsequent rolling is 80 mm (the distance between the protrusions of the caliber roll is It was set to 900 mm) and the flat caliber was set to 100 mm (rolling distance was set to 900 mm).

As a result, when rolled according to the present invention, the width of the flange portion is 501 mm (flange leg length: 262 m).
m), and the flange area was 484 cm ² , and no deterioration of the shape such as displacement of the flange was observed. On the contrary,
Comparative method (when applying a rolling method in which only one type of caliber is passed and then a flat pass is performed so as not to cause shape deterioration, the tip angle Θ of the protrusion of the caliber is 120 ° and the rolling amount is 200 mm)
Then the width of the flange is 461 mm (flange leg length: 223 mm)
The flange area was 404 cm ² .

[0019]

According to the present invention, it is possible to efficiently roll a large-sized rough section material for H-section steel without causing shape deterioration. Further, it is possible to reduce the number of caliber rolls used when rolling such a profile.

[Brief description of drawings]

FIG. 1A is a sectional view of an essential part of a caliber roll arranged in a rolling mill on the upstream side, and FIG. 1B is a sectional view of an essential part of a caliber roll arranged in a rolling mill on a downstream side.

FIG. 2 is a diagram showing a main part of a width end of a slab.

FIG. 3 is a diagram showing a formation state of a flange.

FIG. 4 is a graph showing the effectiveness of setting the reduction amount in a predetermined range in the rolling on the upstream side.

FIG. 5 is a view showing a cross section of the caliber roll used in the examples for the upper half.

[Explanation of symbols]

 1 Caliber 1a Protrusion 2 Caliber 2a Protrusion S Slab

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobumoto Takashiba Nobumoto Takashiba 1-chome, Mizushimagawa Tetsudo, Kurashiki-shi, Okayama Prefecture (no address) Inside the Mizushima Works, Kawasaki Steel Co., Ltd. (72) Naoshi Nagahiro, Mizushimagawa Tetsudo, Kurashiki-shi, Okayama 1 chome (without street number) Kawasaki Steel Works Mizushima Steel Works

Claims (1)

[Claims] 1. A rolling mill provided with a caliber roll having two kinds of tapered projections is arranged on a roll cylinder, and slabs having grooves on both width end faces are sequentially passed through the rolling mill to provide rolls of the rolling mill. When forming the flange part by expanding the groove of the slab with the protrusion of, the tip angle of the protrusion of the caliber roll that first passes the slab shall be smaller than the tip angle of the protrusion of the caliber roll that passes the slab first. The rolling reduction amount is
A method for producing a crude material for H-section steel, which comprises rolling at 40 to 65%.