JPH05177201A - Rolling method for asymmetric H-section steel - Google Patents

Abstract

(57) [Abstract] [Purpose] When manufacturing an asymmetrical H-section steel by the universal rolling method, the bending is reduced and the rolling dimension limit is increased. [Constitution] The rotation speed of the left and right vertical rolls is adjusted independently. Specifically, the method for adjusting the speed of the left and right vertical rolls is to drive the left and right independently, or to adjust the rotational resistance of the non-driven vertical rolls independently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an asymmetrical H-section steel, and a left-right bending when manufacturing an H-section steel having different left and right flange thicknesses by using a universal rolling method which is low in cost and high in productivity. It is intended to manufacture an asymmetrical H-section steel with less heat generation.

[0002]

2. Description of the Related Art Asymmetric H-section steels are often used for beam materials such as building structures and bridges because they have great mechanical advantages, but in view of their cost and productivity, they are generally manufactured by a rolling method. It is being appreciated. However, since the cross section is asymmetric, distortion often occurs during the manufacturing process, and various methods have been proposed to improve the distortion.

For example, there is one disclosed in Japanese Patent Application Laid-Open No. 56-126002, and a characteristic of the technique is that a steel material having asymmetrical upper and lower flange shapes with a web as a boundary is used as a universal mill and a shaping rolling machine continuous with the universal mill. When rolling in
The dimension from the surface corresponding to the flange tip to the surface corresponding to the web of the roll used in the shaping rolling mill is slightly smaller than the target dimension on the thick side of the flange, and is substantially larger than the final target dimension or target dimension on the thin side of the flange. However, there is a rolling method for asymmetrical shaped steel in which the roll gap of the web portion is set within a range that does not reduce the web of the material.

Further, in Japanese Patent Laid-Open No. 59-66902, as a method for producing an asymmetric shaped steel, when a shaped steel having an asymmetric cross section is rolled by a rolling mill having a roll hole type, the asymmetric shaped steel is partially cooled. A method has been proposed. Although this method directly targets unequal-height unequal thick angle steel,
It has been confirmed that it can also be applied to the production of asymmetric H-section steel, but its application limit is small with the left and right flange thickness ratio of the product being about 1.3.

[0005]

However, the former technique is intended for H-shaped steel having a special shape and cannot be applied to ordinary universal rolling.

Even if the latter technique is applied to non-target H-shaped steel, the flange thickness ratio of 1.3 is the limit as described above, and the flange thickness ratio of up to about 2.0 is targeted. It was impossible.

On the other hand, when an asymmetric H-section steel is to be manufactured by universal rolling, there is no effective means for preventing the occurrence of left and right bending due to the difference in left and right elongation rates, and the greatest problem is to solve this. Was becoming.

Therefore, an object of the present invention is to prevent left-right bending when producing an asymmetric H-section steel in universal rolling and to reliably produce an asymmetric H-section steel having a large product flange thickness ratio. is there.

[0009]

In order to achieve the above object, the present invention is to perform rolling while independently adjusting the rotational speeds of the left and right vertical rolls. As a means for adjusting the rotation speed of the vertical rolls, a method of driving the vertical rolls independently from each other or a method of independently determining the rotational resistance of the non-driven vertical rolls can be adopted.

[0010]

The left-right bending of the asymmetric H-section steel is caused by the difference in the left-right elongation ratio due to the difference in the left-right flange thickness. Generally, the factors that determine the elongation of rolled material include rolling reduction, tension, and frictional force.However, since the rolling reduction is determined by the relationship between the material dimensions and the product dimensions, it is used for adjusting the elongation. It's hard to do.

On the other hand, the frictional force is adjusted by adjusting the coefficient of friction. The method of adjusting the friction coefficient is performed by controlling the temperature of the rolled material and lubricating the rolling rolls, but this method has a small adjustment limit and is difficult to finely adjust.

Therefore, a method of adjusting the elongation by adjusting the tension is effective. When rolling the asymmetric H-section steel using a universal mill, the tension can be adjusted by the rotation speed of the vertical roll. By utilizing this principle, the speed of the vertical roll can be independently determined for the left and right sides, and the tensions for the left and right sides can be adjusted.

There are the following methods for making the rotation speed of the vertical roll independent. This method is to drive the vertical rolls that were not driven in the conventional universal mill independently, or to adjust the rotational resistance of the vertical rolls that are not driven. By doing so, it is possible to determine the right and left elongation rates, and it is possible to reduce the bending of asymmetric H-section steels having different flange thicknesses.

Further, this method adjusts the tension unlike the method of partially cooling the steel material, so that it can be applied to asymmetric H-section steels of various sizes, and the production of a product with a flange thickness ratio of up to about 2.0. Is possible.

[0015]

EXAMPLES The present invention will be specifically described below with reference to production examples.

The raw material dimensions immediately before the rough universal rolling shown in FIG. 1 are shown. That is, in the equipment layout shown in FIG. 3, the size of the raw material, the steel billet extracted from the heating furnace,
Rolled down to the dimensions shown in FIG. 1 in a breakdown mill 1, followed by a rough universal mill 2, an edger mill 3,
After rolling by the finishing universal mill 4, it is cut into a predetermined length by the first hot saw 5 or the second hot saw 6, and the asymmetric H-section steel (H700 × W300 × d14 / 14/28 shown in FIG.
Unit: mm) The product can be obtained.

According to the first aspect of the present invention, the vertical roll of the universal mill is not driven, and the rotational resistance is adjusted to the left and right independently to adjust the rotational speed to the left and right independently.

As a vertical roll structure for this purpose, the structure shown in FIG. 4 can be used. That is, the brake roll 9 is rotatably arranged in the housing 10 so as to come into contact with the back surface of the vertical roll 8 integrated with the rotary shaft 7, and the brake 11 is brought into contact with the shaft portion of the brake roll 9. A bearing position adjusting cylinder 13 is provided for the bearing 12. In this example, the sliding of the vertical roll 8 and the brake roll 9 can be prevented by the degree of pressing force of the bearing position adjusting cylinder 13 against the bearing 12. The braking force of the brake 11 can be adjusted by controlling the extension of the rod of the brake actuating cylinder 15. As a result, the brake roll 9 that tries to rotate following the rotation of the vertical roll 8 that is not driven by rolling restricts the rotation of the vertical roll 8, so that the rotation speed of the vertical roll 8 is adjusted. .. This rotational speed can be adjusted by controlling the degree of extension of the rod of the brake actuating cylinder 15. Further, although not shown, similar rotation resistance adjusting means is also provided on the other side, and for example, the rotation resistance of both vertical rolls 8 and 8 is adjusted based on a signal from a bend detector provided on the rolling line, As a result, their rotational speed is adjusted and bending is prevented. FIG. 5 shows a rolled state, and 14 is a horizontal roll.

On the other hand, according to the second aspect of the present invention, both vertical rolls of the universal mill are driven independently left and right (drive side and work side), and the rotational speed of the vertical rolls is independently adjusted left and right. .. Needless to say, a concrete example of this aspect is not shown in the drawings, and both vertical rolls 8, 8
By adjusting the output of the rotary drive motor, the rotation speeds thereof can be adjusted and the occurrence of bending can be prevented.

(Experimental Example) First for adjusting the above-mentioned rotation resistance
According to the embodiment, after the material is rolled down to the dimensions shown in FIG. 1 by the equipment shown in FIG. 3, the rough universal mill, the edger mill, and the finishing universal mill are used.
Rolled to the dimensions shown in. Coarse universal mill (intermediate rolling mill) and finishing universal mill (UF) in this case
Table 1 shows an example of the pass schedule. In Table 1, when the vertical roll resistance coefficient value is set to the value shown in the example of the present invention,
Rolling was possible in each pass without left-right bending.
In this case, when WS (work side) bending occurs, the DS (drive side) vertical roll rotation resistance is set to a large value, and conversely, when DS bending occurs, the WS vertical roll rotation resistance is set to a large value. By doing so, bending was prevented.

On the other hand, like the conventional universal mill, when the values shown in the comparative examples are set so that the vertical roll resistance is not intentionally imparted, the WS bend becomes large in the first pass and the second pass, and the third and subsequent passes. Became impossible to roll.

[0022]

[Table 1]

[0023] T _W: each web thickness immediately after the rough universal mill rolling of the path (mm) TF _D: immediately after the rough universal mill rolling of each path DS flange thickness (mm) TF _W: immediately after the rough universal mill rolling of each pass WS flange thickness (mm) B _E: flange width (mm) K _D immediately Ejjamiru rolling each path: DS side vertical rolls of the resistance coefficient K _W: WS side vertical rolls of the resistance coefficient UF: finishing universal mill

[0024]

As is apparent from the above description, according to the present invention, when manufacturing an asymmetrical H-section steel, there is a great effect in reducing left and right bends, and asymmetrical H-section steels of various sizes. It becomes possible to make.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a raw material before being rolled into an asymmetric H-section steel.

FIG. 2 is a sectional view of an asymmetric H-section steel product.

FIG. 3 is a mill layout diagram for rolling the steel material of FIG. 1 into the product of FIG.

FIG. 4 is a cross-sectional view showing a structural example of adjusting means for adjusting a non-driven vertical roll by rotational resistance.

FIG. 5 is a rolling situation in a universal rolling mill.

[Explanation of symbols]

1 ... Breakdown mill, 2 ... Coarse universal mill, 3
… Edger mill, 4… Finishing universal mill, 5…
1st hot saw, 6 ... 2nd hot saw, 8 ... Vertical roll,
9 ... Brake roll, 11 ... Brake, 14 ... Bearing position adjusting cylinder, 15 ... Brake actuating cylinder

Claims (2)

[Claims] 1. A universal rolling method for H-shaped steel having different left and right flange thicknesses, characterized in that the vertical rolls of the universal mill are driven independently left and right, and the rotational speed of the vertical rolls is adjusted independently left and right. Target H-section steel rolling method. 2. In the universal rolling method for H-section steels having different left and right flange thicknesses, each vertical roll of the universal mill is made non-driving, and its rotational resistance is independently adjusted so that the rotational speed of the vertical roll can be adjusted. A method for rolling an asymmetrical H-section steel, characterized by adjusting the right and left sides independently.