JPH09168815A - Cooling method of wide flange shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cooling method of wide flange shapes whose practicality is high, which is economical and simple and by which torsional deformation is reduced. SOLUTION: The wide flange shapes 1 are closely arranged in the posture of 1 on a cooling bed 2, greatly heavy restraining devices 3 having a heat insulating material 31 consisting of a ceramic are arranged in a state where the heat insulating materials are faced to the webs of the wide flange shapes, the amount of heat radiation from the webs is decreased, torsional deforming-force caused by the temp. difference between the web and the flanges is reduced, the wide flange shapes are restrained with the restraing devices which are hard to move due to the great weight and the generation of torsional deformation at the time of cooling is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of cooling a shaped steel, particularly an H-shaped steel.

[0002]

2. Description of the Related Art In an H-section steel production line, generally, a flange is cooled by a passage type cooling device during or after rolling as shown in FIG. 4 to prevent generation of web waves after cooling. The means to do so are taken. Japanese Patent Laid-Open No. 3-7
The technology disclosed in Japanese Patent No. 9724 and Japanese Patent Application Laid-Open No. 4-103720 corresponds to this.

Also, many techniques have been disclosed for heating the web to bring it closer to the temperature of the flange before finally being naturally cooled. JP 48-14510 A, JP 6
The techniques described in JP-A-3-216923, JP-A-4-141520 and JP-B-5-449 correspond to this.

The above-mentioned technique is for reducing the temperature difference between the web and the flange during rolling of the H-section steel or before the start of spontaneous cooling after rolling. However, even when the temperature of the flange and that of the web are set to be approximately the same when carrying in the cooling bed for spontaneous cooling, the thickness of the flange of the H-section steel is generally thicker than that of the web. The temperature drop of the web during natural cooling is larger than that of the flange.

Particularly, in the H-section steel having a small flange width and a thin flange thickness, there is a problem that deformation called twisting occurs as shown in FIG. The twisting deformation is caused by the buckling of the flange during natural cooling because the web having a smaller heat capacity cools and shrinks first.

Japanese Patent Publication No. 54-20442 discloses a technique for reducing heat radiation from the web by placing heat-retaining particles on the web for heat retention. However, this method does not block the heat radiation from the lower surface of the web, and is insufficient as a heat insulating effect, and the temperatures of the web and the flange cannot be made the same. Further, it is difficult to prevent torsional deformation because no restraint is applied.

On the other hand, Japanese Patent Laid-Open Nos. 1-205033 and 4-138801 propose techniques for preventing warpage deformation, but there is a method for cooling the outer surface of the flange while restraining it. It is disclosed. Although it is considered that these methods can also be applied to prevent torsional deformation, a restraint device that normally requires three or more sets of restraint rolls is installed in the entire cooling bed or the entire transfer device. It is extremely difficult in terms of equipment to do so.

[0008]

As described above, most of the techniques disclosed about how to obtain H-shaped steel with less deformation are temperature differences between the web and the flange at the end of rolling or before the start of spontaneous cooling. Is from the viewpoint of how to reduce. Here, the deformation during natural cooling is not considered so much.

Although some techniques for dealing with the deformation caused by the difference in cooling rate between the web and the flange during natural cooling have been shown, they are problematic in terms of cost and equipment. Therefore, there is a need for a method of cooling an H-section steel that is highly practical, economical, and simple, and that has little torsional deformation.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a cooling method for preventing torsional deformation, while conveying an H-section steel by a cooling bed. When cooling, the restraint device having a heat insulating material on one side is placed with the heat insulating material facing one or more webs of the H-shaped steel placed in the I posture, and cooling is performed on the H-shaped steel. Is the way.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as shown in FIG. 1, a high temperature H-section steel 1 is placed on a cooling bed 2 in a state of I-position, parallel to each other, and in a state where flanges are in contact with each other. Both ends in the length direction are aligned and placed side by side, and the H-shaped steel group is restrained in the width direction of the H-shaped steel from both sides by the restraining devices 3 in a state in which Book Ed stands up.

As shown in FIG. 2, the restraint device includes a heat insulating material 3
1, a steel plate 32 for supporting the heat insulating material, a frame material 33 for preventing the heat insulating material from coming into contact with the flange of the H-shaped steel and being damaged,
It comprises a heavy steel block weight 34.

A heat insulating material is arranged on the surface of the restraint device which faces the web of the H-section steel in the I posture (hereinafter referred to as a heat insulating surface) to reduce the heat radiation from the high temperature web, and H
The cooling rate of the shaped steel web is slowed down, and the deformation force due to the difference in cooling rate between the flange and the web is reduced. The H-shaped steel is prevented from being deformed by sandwiching the reduced deformation force with a heavy weight restraint device.

As shown in FIG. 2, the supporting steel plate of the heat insulating material is provided with frame members 33 made of shaped steel vertically and horizontally in order to prevent the heat insulating material from coming into contact with the flange and being damaged. In the figure, only the cross section of the frame member that is parallel to the longitudinal direction of the H-section steel when the restraint device is used is shown, but a frame member orthogonal to this frame member is also arranged, and this orthogonal frame member is It contacts the flange of H-section steel and restrains the deformation. These frame members are fixed to the supporting steel plates, and the height (distance from the supporting steel plate side end of the frame member to the anti-supporting steel plate side end) is naturally less than or equal to the thickness of the heat insulating material.

If there is only one H-section steel to be cooled, both sides will be sandwiched by restraint devices. In addition, H-section steel is 2
In the case of books, one of the H-shaped steel web faces is the other H
The web side of the shaped steel, the other side facing the heat insulating side of the restraint. (Note that the deformation that occurs on this cooling bed is
Since it is elastically deformed, when the flange and the web are cooled to room temperature, the strain between them is released and no strain or residual stress remains. )

[0016]

[Example] In Example 1, a hot-rolled height of 700 m
m, width 200 mm, flange thickness 16 mm, web thickness 9 mm, length 15 m, seven H-section steels 1 were carried into a cooling bed 2 equipped with a transfer, as shown in FIG. The temperatures of the flange and the web in this state were 545 ± 5 ° C and 550 ± 5 ° C, respectively.

On the cooling bed, seven pieces were arranged in an I-position with the flanges in contact with each other, parallel to each other, and aligned at both ends in the longitudinal direction. In this way many H
When the shaped steels are cooled in a collective state, the webs of the H-shaped steels (No. 2 to No. 6 in this case) placed on other than the both end portions of the webs of the other H-shaped steels facing each other have high temperatures. Therefore, the heat radiation is small, and the cooling rate thereof is not much different from the cooling rate of the thick flange as a result.

H-section steels placed at both ends of the H-section steel group (No. 1)
And No. For 7), the restraint was placed with the insulating surface facing the H-section steel web to reduce heat dissipation from the web.

The insulation of the restraint system is a 10 mm thick ceramic. The supporting steel plate has a thickness of 20 mm. The weight is a steel plate having a thickness of 80 mm, and the weight of one restraint device (a pair of one side) is about 10 tons.

The H-section steel is sandwiched by this restraint device and cooled down to near room temperature while being transferred through the cooling bed.
The flange and web temperatures, with the restraint removed, were in the range of 100 ° C ± 3 ° C and 105 ° C ± 5 ° C, respectively. In this state, there was little stress between the flange and the web, so that twisting deformation did not occur even when the restraint device was removed.

In FIG. 3, a paint surface 3 having a high heat ray reflectivity is formed on the surface of the ceramic heat insulating material of the restraint device shown in FIG.
A restraint device having a greater effect of preventing deformation by providing No. 5 (hereinafter referred to as a reflecting surface) is shown. This device is intended to improve heat retention in a high temperature range (600 ° C to 500 ° C). A paint containing silver-colored aluminum powder having a reflectance of 0.96 was used as the paint. For repeated use in this restraint device, frame members are arranged vertically and horizontally on the heat insulating surface as in the first embodiment. (Not shown)

In Example 2, seven H-section steels having the same dimensions as in Example 1 were used. The temperature of the flange and the web as conveyed after rolling is 555 ± 5 ° C and 550 ± 5 ° C, respectively.
Met. On the cooling bed, the restraint device having the heat insulating material and the reflecting surface described above was arranged at both ends of the H-shaped steel group. After cooling, the temperature of the flange and the web with the restraint removed is 102 ° C ± 2 ° C and 105 ° C ± 105 ° C, respectively.
It was in the range of 2 ° C, and no torsional deformation was observed.

As a comparative example, H having the same size as the above example
Load the same number of shaped steels into the cooling bed under the same temperature condition, and set the distance between the ends of each flange to about 1 in I position.
The length was set to 00 mm and they were arranged in parallel with each other and cooled to room temperature. A twist deformation of about 10 ° per 1 m was observed for the H-section steels placed at both ends, and a twist deformation of about 8 ° per 1 m was observed for the H-section steel placed in the middle.

When the flanges are brought into contact with each other by a restraint device having no heat insulating material and cooling is performed, the H-shaped steel placed at both ends undergoes a torsional deformation of about 7 ° per 1 m. In the H-shaped steel of No. 3, a twist deformation of about 5 ° was observed per 1 m.

On the other hand, when the H-section steels are arranged in a state where the flanges are in contact with each other and only heat insulation is performed without restraint (the weight is not placed on the restraint device described above, and a simple shift is made). For any H-section steel after cooling to room temperature, 1
A twist deformation of about 7 ° was observed per m.

[0026]

As is apparent from the above description, according to the present invention, the following effects can be obtained. (1) Since it is not necessary to make the temperature of the flange lower than the temperature of the web during cooling, there is no possibility that the web buckles and web waves occur during cooling of the flange.

(2) Compared to the method of heating the web so that the web does not cool quickly and performing thermal compensation so that the temperature is the same as that of the flange, and the method of mechanically restraining the torsional deformation, the equipment cost is lower. Fuel cost and electricity cost are low and it is low cost.

(3) Since the force that causes the torsional deformation is reduced by the effect of heat insulation, it is possible to completely prevent the torsional deformation with a small restraining force (contact frictional force with the cooling bed due to the own weight of the restraint device). The equipment is simple and the handling is easy.

(4) By adopting a heat insulating structure in which a frame material and a heat insulating material are combined, a load does not act directly on the heat insulating material, so that the restraint device can be repeatedly used and is economically advantageous. ing.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first embodiment of the present invention.

FIG. 2 is a side view of the restraint device used in the first embodiment of the present invention.

FIG. 3 is a side view of a restraint device used in a second embodiment of the present invention.

FIG. 4 is a diagram showing a cooling method in an H-section steel rolling line.

FIG. 5 is a schematic diagram showing torsional deformation.

[Explanation of symbols]

 1-H section steel 11-flange 12-web 2-cooling bed 3-restraint device 31-heat insulating material 32-support steel plate 33-frame material 34-weight 35-reflection surface

Claims (1)

[Claims] 1. When the H-section steel is allowed to cool while being conveyed in a cooling bed, a restraint device having a heat-insulating material on one surface is placed on one or more webs of the H-section steel in a heat-insulating material. Are arranged in a state of facing each other, and are allowed to cool, thereby cooling the H-section steel.