JPH08174071A - Roller straightening method of wide-flange shape - Google Patents

Abstract

PURPOSE: To provide the roller straightening method of a wide-flange shape capable of straightening a large wide flange shape with thin web thickness. CONSTITUTION: A roller straightening machine to straighten bends by rolling down a web 3 of a wide-flange shape 1 including a horizontal rolls 12 is provided with vertical rolls 11 to roll down both side faces of flanges 2 of the wide-flange shape 1 and a devIce to produce a rolling down force through the vertical rolls 11 in the web height direction. The horizontal rolls 12 and vertical rolls 11 are arranged so as to be offset in the axial direction of horizontal rolls 12, by applying upward/downward bending and bending in the width direction of wide-flange shape at the same time, a shape of the wide-flange shape is straightened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller straightening method for H-section steel by means of a roller straightening machine for straightening a bend by pressing down a web of H-section steel, and in particular, it is manufactured by hot rolling or welding. The present invention relates to a method for correcting the shape of H-shaped steel.

[0002]

2. Description of the Related Art Since H-section steel as manufactured by hot rolling or welding has a bend or a warp as a whole or locally, it is usually shipped straight after being cold straightened. Is. As a cold straightening method, press straightening or roller straightening is often used. However, the former is not efficient and is not suitable for mass production because it is appropriately deformed by a pressing metal fitting while observing the shape before straightening. On the other hand, the latter (roller straightening method) is a method of straightening H-section steel by repeatedly bending it with a large number of rollers, which is efficient and is installed as an online facility at the factory.
It is used.

FIGS. 10 and 11 show a part of the contact state between the straightening roller and the H-section steel in the conventional roller straightening method in a partially extracted manner. As can be seen in these figures, the conventional roller straightening machine load method is shown in FIG.
0, a web reduction method in which the surface of the web 3 of the H-section steel 1 is loaded by the outer peripheral surface of the roller 4, and the end surface of the flange 3 of the H-section steel 1 is loaded by the outer peripheral surface of the roller 5, as shown in FIG. There are two types of monkey flange reduction method. However, whichever rolling method is adopted, the problems described below cannot be avoided.

That is, the drawback of the web reduction method is that, in the case of H-section steel having a flange width wider than the web plate thickness, the load by the roller is converted into a sledge of the web, which causes sufficient bending deformation of the flange. Not only that, but only the local contact between the roller and the web can be plastically deformed and, in severe cases, even cracked. Japanese Examined Patent Publication No. 57-61488 proposes to devise the shape of the roll for pressing the web in order to suppress such local deformation, but in consideration of the situation where a thinner web product is required, Such a method cannot solve the essential problem.

Further, the drawback of the flange reduction method is that when the flange width is wide and a large bending load is required, the flange end face in contact with the roller is crushed and the flange width is significantly reduced. is there. Such problems are caused by Japanese Patent Publication No. 56-40646 and Japanese Patent Laid-Open No. 53-1.
As proposed in Japanese Patent No. 41158, the load is reduced by increasing the distance between the rollers, and the contact area between the roller and the flange is increased by increasing the diameter of the roller, but this is reduced to some extent. Not only does this lead to larger equipment and higher construction costs, but increasing the roller spacing also lengthens the length of the uncorrectable portion at both ends of the H-section steel, so these means are naturally limited. .

[0006]

As described above, it is obvious that the H-section steel having a large cross section cannot be effectively corrected by either the web reduction method or the flange reduction method, but it is unavoidable. The current situation is to use the web reduction method. In order to solve the drawbacks of the above two methods, FIG.
As shown in (for example, Japanese Examined Patent Publication No. 57-11728), a method of simultaneously pressing down the flange 2 and the web 3 by the rollers 4 and 5 has been proposed, but this method is also distributed to the flange 2 and the web 3. It is difficult to set the load to
If the height of the web 3 is expanded, the toes of the flange 2 may be crushed, the mechanism is complicated, and the web thickness is further reduced, it is inevitable that the above-mentioned problems are exposed.

Further, Japanese Patent Publication No. 56-45684 proposes a rather clever method for lowering the surface pressure applied to the flange when the flange is pressed down. However, in this method, the circumference of the portion in contact with the flange is proposed. Since the speeds are different, deformation is induced in the direction of the tilt of the flange, the load at the part where the flange starts contacting and the part that comes out of the contact of the flange becomes high, and as a straightening machine, it is a dedicated H-section steel machine. There are problems such as becoming.

Further, in Japanese Patent Application Laid-Open No. 4-59124,
We are trying to solve the above problem by providing a vertical roll for web reduction and restraining the web deformation by restraining the flange, but simply restraining the flange against a large load such as a straightening load is not effective. It is clear that it is insufficient.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a roller straightening method for H-section steel capable of straightening even a large H-section steel having a small web thickness. .

[0010]

A roller straightening method for H-section steel according to the present invention includes a horizontal straightening roll, and a roller straightening machine for straightening a bend by pressing down a web of the H-section steel. A vertical roll for rolling down both sides and a device for generating a rolling force through the vertical roll in the height direction of the web are provided so that the bending stress due to the web rolling and the compressive stress due to the vertical roll are applied to the web cross section. The horizontal roll and the vertical roll are arranged offset from each other in the axial direction of the horizontal roll, and the shape of the H-section steel is corrected by bending the H-section steel in the strong axis direction simultaneously with vertical bending. That is,
When straightening the bend by rolling down the flange of H-section steel and the root of the web with a roller straightening machine,
By applying compressive stress from the side of the flange with a vertical roll to suppress the change in web height, the vertical roll and horizontal roll positions are offset to the left and right positions of the H-section steel to reduce the web rolling load. You have achieved your purpose.

[0011]

Next, the operation of the present invention will be described. FIG. 1 shows the principle of a roller straightening method for H-section steel according to the present invention. In the same figure, (a) is a front view of a straightening machine to which the present invention is applied, (b) is a plan view thereof, and (c) is a diagram showing a relationship of forces acting on the straightening machine. In the present invention, when the horizontal straightening of the H-section steel is straightened by the roller straightening machine, the vertical roll 11 and the horizontal roll 12 are arranged offset in the axial direction of the horizontal roll 12, and the horizontal roll (web rolling roll) is arranged. The bending height is repeatedly corrected by 12 and the vertical roll 11 is pressed down while the vertical bending is performed simultaneously with the strong axial bending of the H-section steel so that the height of the web does not change and fillet cracking does not occur. And H
Corrects left and right bending of shaped steel. Here, vertical roll 11
The stands for installing are shown as all stands,
If the vertical roll 11 is installed in at least one or more stands for straightening the right and left bends, the effect is exerted. In the figure, the offset amount is indicated by t, and the vertical roll 11
The horizontal roll 12 is not subjected to the right-and-left bending correction force due to the rolling force.

FIG. 2 is a view showing a stress state in the H-section steel cross section by the conventional web reduction method. The web 3 is compressed and pulled by bending by the roll 4, and the same stress is applied to the fillet portion. Bending is applied to the flange 2 by pushing the web 3, and the foot has compressive and tensile stresses in the longitudinal direction. In the figure, a circle mark is attached to a portion where the tensile stress is generated, and the tensile stress is generated inside thereof. The reason why the height of the web 3 changes and cracks occur in the fillet portion is mainly due to this tensile stress, and it is necessary to reduce this in some way.

In Japanese Patent Laid-Open No. 4-59124, at this time, a vertical roll is provided on the outside of the flange to restrain the flange to increase the bending rigidity of the web, and the deformation thereof is suppressed to solve the above problem. ,
This rigidity seems to be effective in the range where the rolling force of the horizontal roll is small, but if a large force such as a straightening load works and it is in a plastically deformed state, the flange will actually be in the current straightening. Is bound by a horizontal roll (web reduction roll) as shown in FIG. 3 (see circled portions in the figure), and it can be said that they are in almost the same situation. Therefore, simply restraining the vertical roll cannot suppress the change in the height of the web as compared with the conventional method, and further improvement is required.

The present inventors recognize that the change in the height of the web and the crack in the fillet portion are caused by the tensile stress, and therefore, in order to exert the effect of the vertical roll, it is necessary to positively apply the compressive stress to the web. I got the finding that there is. FIG. 4 is a diagram showing a stress state at this time, and it can be seen that the harmful tensile stress is reduced within the elastic range by applying compressive stress to the web 3 by the vertical roll 11.

The compressive stress due to the vertical roll required here is given by the following equation from the simple theory of bending back under tension.

[0016]

[Equation 2]

Σ _T : Applied compressive stress σ _y : Yield stress of material t: Plate thickness of web portion p: Bending curvature given to web portion

Further, it goes without saying that reducing the load of the horizontal roll (web reduction roll) itself also exerts an effect of suppressing the deformation (fillet cracking, web height change) due to the local load. To deal with this, both vertical rolls and horizontal rolls are offset in the axial direction of the horizontal rolls, and so to speak, by repeatedly bending the H-section steel in the strong axis direction (bending around the y axis in FIG. 1).

FIG. 5 is a schematic diagram of the residual stress of the H-section steel having bending after rolling and cooling. In a sense, when this residual stress is reduced, the H-section steel is straightened. Can be said. Further, FIG. 6 shows the stress state when the H-section steel without residual stress is repeatedly bent in the strong axis direction. FIG. 7 shows a combination of the stresses of FIGS. 5 and 6.
However, due to the residual stress of the H-section steel after rolling and cooling and the stress due to repeated bending in the strong axis direction, the short length portion of the flange portion is pulled and the long length portion is compressed. It can be seen that the repeated plastic deformation is effectively performed. Therefore, by offsetting the vertical rolls / horizontal rolls in the axial direction of the horizontal rolls, this effect can be effectively exhibited, and the amount of web reduction can be reduced.

The intervals and the number of vertical rolls for applying compressive stress to the bending of these webs are preferably set at each stage of the conventional web pressing roller, and the effect is exhibited whether they are driven or not driven. Is. Further, the vertical roll pair of the present invention may be provided only in the front stage portion where a large load is applied, and the rear stage portion may be constituted by normal web or flange roller straightening. Of course, it can be applied to both a cantilever type and a double-sided type straightener. Then, by properly laying a guide for properly inserting into the straightening machine of the present invention, an interval adjusting device for the vertical roller set, a vertical position adjusting device, and a driving device of the present invention, continuous H-section steel of various cross-sectional dimensions can be obtained.・ Effective correction is possible.

[0021]

【Example】

Example 1. The effect of the straightening machine / straightening method (FIG. 1) according to the present invention is shown in comparison with the conventional method. Table 1 is a table showing the dimensions of the material to be straightened and the specifications of the actual straightening machine. Further, Table 2 is a table showing the setting of the intermesh and the offset position as compared with the conventional web straightening method. In the conventional method, no offset is performed. When offsetting was performed by the conventional method, the change in web height was large and fillet cracks were also generated, making it unusable as a product. Further, in the present invention, the amount of reduction by the horizontal roll is small. Table 3 is a table showing the effect of the method of the present invention in comparison with the conventional method.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

In the straightening method according to the present invention, the change in the web height is eliminated as compared with the conventional web draft straightening and, of course, there is no fillet crack. Further, FIG. 8 is a characteristic diagram showing a change in web height due to vertical roll reduction according to the present invention, and as shown in the figure, it can be seen that the web height itself can be controlled by the vertical roll reduction load. The characteristics shown in FIG. 8 all show average values.
FIG. 9 is a diagram in which the hardness distribution of the fillet portion is investigated. It can be seen that the hardness of the fillet portion increases due to the reduction of the vertical roll.

[0026]

As described above, according to the present invention, the horizontal roll and the vertical roll are offset in the axial direction of the horizontal roll so that the bending stress due to the web reduction and the compressive stress due to the vertical roll are applied to the cross section of the web. Since the shape of the H-section steel is straightened by bending it in the direction of the strong axis of the H-section steel at the same time as bending up and down, productivity is reduced because there is no effective conventional straightening method. It is possible to efficiently correct the shape of a large H-section steel that has been corrected by a press, and it is possible to exhibit an excellent effect of improving product quality.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the principle of a roller straightening method for H-section steel according to the present invention.

FIG. 2 is a diagram showing a stress state by a conventional correction method.

FIG. 3 is a diagram showing a restrained state of a flange in a conventional straightening method.

FIG. 4 is a diagram showing a vertical roll rolling condition in the present invention.

FIG. 5 is a diagram showing a residual stress state of an H-section steel having bending after cooling by rolling.

FIG. 6 is a diagram showing a stress state when the H-section steel is bent in the strong axis direction.

FIG. 7 is a diagram showing a stress state when an H-shaped steel having a vertical bend is bent in the strong axis direction.

FIG. 8 is a characteristic diagram showing a change in web height (rolling down effect) due to rolling down of a vertical roll according to the present invention.

FIG. 9 is a characteristic diagram showing a change in hardness of a fillet portion due to reduction of a vertical roll according to the present invention.

FIG. 10 is an explanatory diagram of a conventional web rolling correction method.

FIG. 11 is an explanatory diagram of a conventional flange reduction correction method.

FIG. 12 is an explanatory view of a conventional web flange reduction method.

[Explanation of symbols]

 1 H-section steel 2 Flange 3 Web 11 Vertical roll 12 Horizontal roll (web reduction roll)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Misao Makinohara 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Yuji Matsuoka 1-2-1, Marunouchi, Chiyoda-ku, Tokyo No. Nippon Steel Pipe Co., Ltd. (72) Inventor Shinichi Nagahashi, 1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Atsushi Watanabe 1-2, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan KK (72) Inventor Minoru Komatsubara 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan KK

Claims (3)

[Claims] 1. A roller straightening machine which includes a horizontal roll and straightens a bend by rolling down a web of H-section steel,
A vertical roll for rolling down both side surfaces of the flange of the H-section steel and a device for generating a rolling force in the height direction of the web through the vertical roll are provided. The horizontal roll and the vertical roll are arranged so as to be offset in the axial direction of the horizontal roll so as to be loaded, and the shape of the H-section steel is corrected by bending the vertical section at the same time as bending the H-section steel in the strong axis direction. A roller straightening method for H-section steel, characterized in that 2. The method for straightening a roller for H-section steel according to claim 1, wherein a vertical roll and a rolling-down mechanism therefor are installed on at least one of the horizontal rolls to straighten the shape of the H-section steel. . 3. The compressive stress applied by the vertical roll satisfies the relationship of the following equation:
Roller straightening method for H-section steel described. [Equation 1] σ _T : Compressive stress applied σ _y : Yield stress of material t: Plate thickness of web portion ρ: Bending curvature given to web portion