JPH06297028A - Method for cooling h-steel - Google Patents

Abstract

PURPOSE:To uniformly cool an H-steel with water by forming a water stream on the inner surface of the H-steel and controlling the velocity of the water stream in accordance with the necessary quantity of heat dissipation. CONSTITUTION:In a method that the wall surface 2 is provided along the inner surfaces 1a of the flanges, surface 1b of the web and inner surfaces 1c in the vicinities of fillets of the H-steel 1 and cooling is executed by jetting water from nozzles which are provided in the wall surface 2 at the time of cooling the H-steel 1 following on the heels of rolling, cooling is executed by taking the gap distance d1 between the inner surface 1a of the flange and the part 2a opposing to the flange on the wall surface and the gap distance d1 between the surface of the web and the part 2b opposing the web on the wall surface 1.5-5 times the gap distance d2 between the inner surface 1c in the vicinity of the fillet and the part 2c opposing the fillet on the wall surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when water-cooling an H-section steel, forms a water flow on the inner surface of the H-section steel, and makes the speed of the water flow according to the heat removal required amount of each part of the H-section steel. By
The present invention relates to a cooling method for H-section steel that enables uniform cooling.

[0002]

2. Description of the Related Art In recent years, the quality required for H-section steel has become more and more strict in terms of high strength, low yield ratio, narrow yield point or improvement in weldability. In order to meet such demands, the cooling capacity is enhanced and H
Uniform cooling of the section of shaped steel is desired. This is particularly required when manufacturing a product having high strength and toughness with a thick carbon material or a component having a low carbon equivalent aimed at improving weldability.

Since H-section steel is used as a structural material,
It is necessary to avoid the partial deterioration of the material in the section of the shaped steel as much as possible, and for this reason, it is becoming more and more necessary to uniformly cool the whole.

Under these circumstances, in cooling H-section steel in recent years, not only the outer surface of the flange (vertical portion) but also the inner surface of the H-section steel, that is, the inner surface of the flange and the web (horizontal portion),
It has become necessary to actively cool.

As an example of a cooling method aimed at meeting this demand, there is a method described in JP-A-60-77924. This invention is characterized in that, following hot rolling, a laminar water jet is applied to the flange and a partial laminar water jet and a partial water layer are applied to the web.

[0006]

However, in the method described in JP-A-60-77924, the cooling capacity can be enhanced by positively cooling the inner surface of the H-section steel, but uniform cooling of the cross section can be achieved. Can not.

The reason is that in the cross section of the H-section steel, the fillet portion, which is the intersection of the flange and the web, has a small cooling area with respect to the volume to be cooled. Therefore, in order to uniformly cool the whole, the surface near the fillet portion is particularly required. It is necessary to cool strongly and cool the other surfaces weaker than that. That is, in other words, the cooling strength corresponding to the required amount of heat removal from the surface of each portion of the H-section steel is required. For the above reasons, the method described in Japanese Patent Laid-Open No. 60-77924 described above can satisfy only this requirement because the surface of the entire steel material can be made to have substantially the same cooling strength.

According to the present invention, when the H-section steel is water-cooled, a water flow is formed on the inner surface of the flange and the surface of the web, and the speed of the water flow is adjusted according to the extraction required amount of each part of the H-section steel. This is a cooling method for H-section steel that enables uniform cooling.

[0009]

According to the present invention, when cooling the H-section steel 1 subsequent to rolling, the flange inner surface 1a of the H-section steel 1, the surface 1b of the web and the inner surface 1 near the fillet are formed.
In the method in which a wall surface 2 is provided along c, and water is jetted from a nozzle provided inside the wall surface 2 to cool the wall surface, a flange inner surface 1
The gap distance d1 between a and the wall surface flange facing portion 2a and the gap distance d1 between the web surface 1b and the wall surface web facing portion 2b are set to 1.5 to 5 times the gap distance d2 between the inner surface 1c near the fillet and the wall surface fillet facing portion 2c. It is characterized by cooling.

According to the method of the present invention, the gap distance on the surface other than the vicinity of the fillet portion is made larger than that near the fillet portion to reduce the flow velocity of water, reduce the cooling strength other than near the fillet portion, and achieve uniform cooling. It's something you want to achieve.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings along with the operation thereof.

FIG. 1 is a vertical sectional view showing an embodiment of the present invention. In FIG. 1, the H-section steel 1 is cooled while being conveyed by a conveying roll 6.

A wall surface 2 is provided on the inner surface of the H-section steel 1 along the longitudinal direction of the H-section steel 1, the gap distance d1 between the flange inner surface 1a and the wall surface flange facing portion 2a, and the surface 1b of the web.
And the gap distance d1 between the wall surface web facing portion 2b and the gap inner surface 1c near the fillet and the wall surface fillet facing portion 2c.
1.5 to 5 times, preferably 2 to 3 times. here,
The vicinity of the fillet refers to a fillet vicinity range w1 in the figure on the inner surface of the H-section steel 1, where w1 is 1 of the flange height w2.
/ 20 to 1/10, 1/20 to 1/10 of web width w3
It is a degree.

The gap distance d2 is 10 to 20 m.
m is desirable.

A cooling nozzle 3 is provided in the wall surface 2, and the cooling nozzles 3 are arranged in a required number along the longitudinal direction of the H-shaped steel 1.

The wall surface 2 is vertically symmetrically arranged,
In this embodiment, a closed space is formed and is connected to a pipe (not shown) so as to function as a header. However, the wall surface 2 does not necessarily have to function as a header, and the cooling nozzle 3
You may connect the pipe directly to.

An outer surface cooling nozzle 4 is appropriately provided outside the flange by a conventional method.

The operation of this embodiment will be described below. Figure 1
At this time, when water is jetted from the cooling nozzle 3, the H-section steel 1
The gap between the wall surface 2 and the wall surface 2 is filled with water, and a water stream is formed. After cooling the H-section steel 1, the water stream is discharged from the flange end portion and the wall surface opening portion 5.

The velocity of the water flow during this period is governed by the gap distance d1 and the gap distance d2 between the H-section steel 1 and the wall surface 2. That is, the water flow is the fastest in the gap between the inner surface 1c near the fillet and the wall surface fillet facing portion 2c, and the water flow passes through the gap between the flange inner surface 1a and the wall surface flange facing portion 2a and between the web surface 1b and the wall surface web facing portion 2b. The cross-sectional area increases and the velocity of the water flow decreases. By changing the velocity of the water flow in this manner, the desired cooling strength of each portion can be obtained, and cooling can be performed in accordance with the heat removal required amount of each portion of the H-section steel to achieve uniform cooling.

The gap distance d1 is equal to the gap distance d.
When the ratio d1 / d2 of 2 is less than 1.5 times, the water flow velocity damping effect is small, and the flange inner surface 1a and the web surface 1b are overcooled, which is not preferable in terms of shape and material.
When the ratio d1 / d2 exceeds 1.5 times,
It becomes difficult for the water flow to be formed along the inner surface of the H-section steel 1, which is not preferable for uniform cooling.

In the present invention, the desired cooling strength of each portion is obtained by changing the velocity of the water flow in this way, and H
Cooling can be performed according to the heat removal required for each section of the shaped steel, and uniform cooling is possible.

The results of cooling using the method of the present invention will be described below.

In the embodiment shown in FIG. 1, the gap distance d2 between the vicinity 1a of the fillet portion and the wall surface 2a is 20 mm, and the other gap distance d1 is 50 mm.

FIG. 2 is an example of a vertical sectional view showing the outline of the comparative example disclosed in the above-mentioned Japanese Patent Laid-Open No. 60-77924.
In FIG. 2, the gap distance between the H-section steel 1 and the wall surface 2 is uniformly 20 mm.

Table 1 shows a comparison between the results of the examples of the present invention and the results of the comparative examples.

[0026]

[Table 1]

In any case, the flange thickness is 40 mm,
900 mm thick H-section steel cooled with a web thickness of 900
800 ℃ from the temperature data of the flange excluding the fillet part (hereinafter referred to as the flange), the web excluding the fillet part (hereinafter referred to as the web) and the fillet part. Table 1 shows the average cooling rates from 1 to 500 ° C. Considering the requirements of the material, the target value of the cooling rate is 5 ° C./s or more in each part and is close to 5 ° C./s, and is aimed at strong cooling and uniform cooling as a whole.

By cooling using the method of the present invention, a desired cooling rate is obtained at each part of the H-section steel,
Moreover, it was possible to achieve almost uniform cooling as a whole.

On the other hand, in the comparative example, the cooling rate of the flange was about 1.4 times the cooling rate of the fillet portion, and uniform cooling was not achieved.

[0030]

As described above, according to the present invention,
When cooling the H-section steel, the surface in the vicinity of the fillet portion can be strongly cooled, which enables more uniform cooling and realizes desirable cooling in terms of material and shape.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an example of an embodiment of the present invention.

FIG. 2 is a vertical sectional view for explaining a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... H-section steel 1a ... Flange inner surface 1b ... Web surface 1c ... Fillet vicinity inner surface 2 ... Wall surface 2a ... Wall surface flange facing portion 2b ... Wall surface web facing portion 2c ... Wall surface fillet facing portion 3 ... Cooling nozzle 4 ... External cooling nozzle 5 ... Opening part 6 ... Conveying roll d1 ... Gap distance d2 ... Gap distance w1 ... Fillet vicinity range w2 ... Flange height w3 ... Web width

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masao Kurokawa No. 1 Tsukiko Hachiman-cho, Sakai City Nippon Steel Co., Ltd. Inside the Sakai Works (72) Inventor Kazuhiro Teraura No. 1 Tsukiko Hachiman-cho, Sakai City New Nippon Steel Stock company Sakai Works

Claims (1)

[Claims] 1. When cooling the H-section steel (1) following rolling, a wall surface is formed along the inner surface (1a) of the flange of the H-section steel (1), the surface (1b) of the web and the inner surface (1c) near the fillet. In the method of providing (2) and jetting water from a nozzle provided in the wall surface (2) to cool, the gap distance (d1) between the flange inner surface (1a) and the wall surface flange facing portion (2a) and the web surface ( 1b) and the wall surface web facing portion (2b) are separated by a gap distance (d1) of 1.5 to 5 times the gap distance (d2) between the inner surface (1c) near the fillet and the wall surface fillet facing portion (2c). Characteristic H-section steel cooling method.