JPH1034229A - Manufacture of steel pillar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently manufacture a steel pillar having a thickness part excellent in dimensional accuracy. SOLUTION: By heating the necessary position of a square pipe 2 to the vicinity of the lower limit temp. of a temp. at which crystal grains are coarsened, also heating a short square sleeve 8 which is possible to fit on the outside of the square pipe 2 to a working temp. at which the sleeve is plastically deformed, fitting the sleeve 8 on the heated part H of the square pipe 2 and pressing so that the sleeve 8 is bitten into the heated part H of the square pipe 2 from the outside using press dies 9, 10, a thick thickness part consisting of the heated part H and the sleeve 8 is formed. Successively, by cooling the heated part H of the square pipe 2 in the thick thickness part from the inside so as to get an intermediate temp. between the lower limit temp. of the temp. at which the crystal grains are coarsened and the ordinary temp., also rapidly cooling the sleeve 8 to the vicinity of the lower limit temp. of the temp. at which the crystal grains are coarsened and, after that, executing slow cooling, the sleeve 8 is shrinkage fit on the square pipe 2 by temp. difference between the heated part H and the sleeve 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a steel column using a square pipe, which can efficiently manufacture a steel column having a thick portion with high dimensional accuracy.

[0002]

2. Description of the Related Art FIG. 11 shows an example of a conventional steel column. A steel column 1 is generally constituted by a square pipe 2 having a square cross section, and is mounted on a floor of a building in the middle of its length. At a corresponding position, a joint portion 6 (joint portion) is formed in which a plurality of screw holes 5 for joining the beam 3 via the mounting bracket 4 are formed. It is necessary to reinforce because the strength is weakened by the perforation of the screw hole 5.

[0003] The connection portion 6 of the steel column 1 is conventionally formed as shown in FIG.
As shown in FIG. 2, a thick portion 7 having a greater thickness than the other rectangular pipe 2 is used to increase the strength.

Conventionally, a thick portion 7 is formed on a connection portion 6 of the steel column 1.
As a technique for forming a rectangular pipe 2, a reinforcing member is additionally fixed to the outside of the rectangular pipe 2 by welding or bolts, or a thick rectangular short pipe is welded between the rectangular pipes 2 by cutting the middle of the pipes. In such a method, the connection part 6 is connected to the thick part 7.
It takes a lot of trouble and time to perform the above, and there is a problem that the manufacturing cost of the steel column 1 increases.

[0005] A method of manufacturing the steel column 1 in which a required portion of the rectangular pipe 2 is heated and compressed to form the connection portion 6 by the thick portion 7 has also been considered.

[0006]

However, a method of forming the thick portion 7 by heating and compressing the rectangular pipe 2 is a conceivable method, but the flatness of the outer surface of the thick portion 7 and the thick portion 7 are not considered.
It is difficult to control the dimensional accuracy and the like of the steel columns, and therefore, there is a problem that it is not possible to provide a uniform steel column 1 having excellent dimensional accuracy.

The present invention has been made in view of such circumstances, and has a seam having a thick portion with excellent dimensional accuracy (weld joining).
It is an object of the present invention to provide a method for manufacturing a steel column which can efficiently manufacture a steel column having no steel.

[0008]

According to the first aspect of the present invention,
A rectangular pipe and a rectangular short sleeve that can be fitted to the outside of the rectangular pipe are used, and a range longer than the length of the sleeve at a required position of the rectangular pipe is heated to near a lower limit temperature of a temperature at which crystal grains are coarsened. Along with heating the processing temperature to plastically deform the sleeve, fitting the sleeve to the heating part of the square pipe, and pressing from outside so that the sleeve bites into the heating part of the square pipe using a press die, Forming a thick portion consisting of a heating portion and a sleeve, and then cooling the heating portion in the thick portion from the inside so as to be an intermediate temperature between the lower limit temperature of the temperature at which the crystal grains are coarsened and the normal temperature, and the sleeve. Is rapidly cooled to near the lower limit of the temperature at which the crystal grains become coarse, then gradually cooled, and the sleeve is shrink-fitted into a square pipe due to the temperature difference between the heating part and the sleeve. It relates to the production process, the steel columns to be.

According to a second aspect of the present invention, when the sleeve is pressed, the sleeve is pressed by using a pair of opposed right-angle groove-shaped press dies, and then the square pipe is rotated by 90 ° and pressed again. And a method for manufacturing a steel column, characterized by repeating the above.

In the first aspect of the present invention, the sleeve is pressed so as to bite the outside of the rectangular pipe, and the sleeve is firmly integrated with the rectangular pipe by shrink fitting to form a thick portion. A seamless and stable quality steel column having a thick portion with excellent flatness and dimensional accuracy can be efficiently manufactured at low cost.

Further, since the heating portion of the rectangular pipe heats only up to the lower limit of the temperature at which the crystal grains are coarsened, the crystal grains are not coarsened, and the sleeve is heated to a processing temperature at which plastic deformation occurs. Press, so that the sleeve can be compression molded with a small pressing force, and after pressing, the sleeve is quenched to near the lower limit of the temperature at which the crystal grains are coarsened, thereby densifying the crystal grains. As a result, the quality is not affected by the change in composition or the residual stress by performing slow cooling.

According to the second aspect of the present invention, the operation of pressing the sleeve using a pair of right-angled grooved pressing dies opposed to each other, and subsequently rotating the square pipe by 90 ° and pressing the sleeve again is repeated. Therefore, the press forming operation of the sleeve can be easily performed.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

According to the present invention, a short sleeve 8 for forming a thick portion is fitted on the outer periphery of a steel square pipe 2 having a square cross section as shown in FIGS. The present invention relates to a method of manufacturing a steel column 1 having a thick portion 7 as shown in FIGS.

FIGS. 1 to 3 show an example of a press device used for forming a thick portion in the embodiment of the present invention. In the figure, reference numeral 28 denotes a rectangular pipe 2 which is horizontally and at a corner 2 '.
Is a support base for supporting in a vertical and horizontal direction. A sleeve 8 is fitted to the square pipe 2 placed on the support base 28, and the sleeve 8 is pressed to be integrally fixed to the square pipe 2. Press dies 9, 10 are provided to face each other in the horizontal direction.

Each of the press dies 9, 10 has a length longer than that of the sleeve 8 as shown in FIG. 2, and has a substantially V-shape as shown in FIG. The press dies 9, 10 are provided with right-angle grooves 9a, 10a corresponding to the portion 2 ', respectively.
Are driven so as to approach and separate from each other.

[0017] The press die 9 is adapted to the space 13 of the square is formed upon contact proximity to, as shown in FIG. 3, the interior angle dimension L ₁ of the space 13 is square pipe 2 is slightly larger than the outer angle dimension L ₂ (FIG. 1),
For example, it is increased by the thickness of the rectangular pipe 2. As a press die, two opposing parallel surfaces of the rectangular pipe 2 are pressed by a first press die having a parallel press surface, and the remaining two opposing parallel surfaces are then pressed by a second press die. It may be one that is pressed by a press die.

In FIG. 4, reference numeral 14 denotes a heating device for heating the sleeve 8, and the heating device 14 has a sleeve 8 therein.
And a heater 16 for heating the sleeve 8 is provided in the furnace 16 so as to heat the sleeve 8. Deformation processing temperature T ₂ (700 ° C. to 900
C.) (see FIG. 9).

In FIG. 5, reference numeral 18 denotes a heating device for heating the rectangular pipe 2. The heating device 18 includes a furnace 16 in which the rectangular pipe 2 is inserted. It is supported by an external support 19. The furnace 16 is provided with a heater 17 for heating a required position of the rectangular pipe 2 in a range slightly larger than the length of the sleeve 8, and a lower limit temperature of a temperature at which crystal grains of the rectangular pipe 2 become coarse. The heating portion H is formed by heating to around T ₁ (400 ° C.) (see FIG. 9), for example, 350 ° C. to 400 ° C.

6 and 7, reference numeral 20 denotes an internal cooling device which is inserted into the rectangular pipe 2 to cool the heating portion H of the rectangular pipe 2, and the cooling water 22 from the water supply pipe 21 is injected by the injection nozzle 23. An outer cooling device 24 for cooling the sleeve 8 by uniformly jetting it to the heating section H, and cooling water 2 from the water supply pipe 25.
The injection nozzle 2 surrounds the outside of the sleeve 8 in an annular shape as shown in FIG.
6, cooling is performed by uniformly spraying onto the sleeve 8.

An infrared thermometer 27 detects the temperature of the sleeve 8 and controls the temperature of the sleeve 8 during cooling. The temperature of the heating portion H of the rectangular pipe 2 and the temperature of the sleeve 8 at the time of cooling can also be controlled by the injection time of the cooling water 22.

The procedure and operation of the embodiment of the present invention will be described below with reference to FIGS. 1 to 7, FIG. 8 showing the operation process flow, and FIG. 9 showing the temperature conditions of the rectangular pipe 2 and the sleeve 8. Will be described.

As shown in FIG.
4, a processing temperature T _{2 at} which the sleeve 8 is plastically deformed by the heater 17 by being inserted into the furnace 16, for example, 700 ° C. to 900 ° C.
Heat to

Further, the square pipe 2 is inserted into the furnace 16 of the heating device 18 shown in FIG.
(FIG. 11 and FIG. 12)
Is heated to a temperature T ₁ lower than the lower limit of the temperature at which the crystal grains are coarsened, for example, 350 ° C. to 400 ° C. in a range longer than the length, to form the heating portion H. At this time, when forming the thick portions 7 at a plurality of locations in the longitudinal direction of the rectangular pipe 2, a plurality of the heating devices 18 are arranged at predetermined intervals and heating is performed simultaneously to form a plurality of heating portions H at the same time. And a plurality of heating devices 14 and a plurality of sleeves 8
Are heated simultaneously.

The heated sleeve 8 is pinched and held by extending the hydraulic cylinders 11 and 12 so as to fit into the right-angle grooves 9a and 10a of the press dies 9 and 10 shown in FIGS. Then, the rectangular pipe 2 having the heating section H formed therein is inserted into the sleeve 8 thus held, and the heating section H of the rectangular pipe 2 is aligned with the sleeve 8, and then the hydraulic cylinders 11 and 12 are extended. Then, the press molds 9 and 10 are brought close to each other to compress the sleeve 8 by pressing. At this time, since the sleeve 8 is preliminarily heated to a temperature at which it is plastically deformed, compression molding can be performed with a relatively small pressing force.

Subsequently, the rectangular pipe 2 is rotated 90 degrees as indicated by the arrow in FIG. 1 and pressed again. This operation is repeated, and when the press dies 9 and 10 come into contact with each other as shown in FIG. 3, the sleeve 8 enters the heating portion H of the rectangular pipe 2, and at this time, the flatness of the sleeve 8 is reduced. It is determined, and the exterior angle dimension internal angle dimension L high dimensional accuracy of the thickness portion 7 which is matched to _one of the space 13 of the press die 9 and 10 are formed.

Subsequently, the rectangular pipe 2 on which the thick portion 7 is formed is taken out from the pressing dies 9 and 10, and as shown in FIGS. 6 and 7, the inside cooling device 20 is inserted into the rectangular pipe 2 and , An outer cooling device 24 is arranged on the outer periphery of the sleeve 8, and the cooling water 22 is supplied to the heating section H by the inner cooling device 20.
Is uniformly sprayed to cool the heating section H to an intermediate temperature between the lower limit temperature T ₁ (approximately 400 ° C.) of the temperature at which the crystal grains become coarse and the normal temperature (25 ° C.), for example, about 200 ° C. The outer cooling device 24 rapidly cools the sleeve 8 to around the lower limit temperature T ₁ (400 ° C.) at which the crystal grains become coarse. Due to the rapid cooling of the sleeve 8, the sleeve 8 is cooled to the processing temperature T.
_{2 The} crystal grains coarsened by heating to (700 ° C to 900 ° C) are densified. At this time, even if the heating section H is quenched, the size of the crystal grains hardly changes because the temperature is low.

Subsequently, the square pipe 2 and the sleeve 8
Is gradually cooled. At this time, while the heating section H is gradually cooled from about 200 ° C., the sleeve 8 is gradually cooled from about 400 ° C., so that the temperature difference of about 200 ° C. causes the sleeve 8 to be heated to the heating section H. Will be fitted.

As described above, as shown in FIG. 10, a steel frame having a thick portion 7 in which the sleeve 8 is pressed so as to bite into the square pipe 2 and the sleeve 8 is firmly integrated with the square pipe 2 by shrink fitting. The pillar 1 can be manufactured.

Even if the heating is performed at a temperature equal to or higher than the lower limit temperature T ₁ (about 400 ° C.) of the temperature at which the crystal grains are coarsened, the crystal grains will not be coarsened unless the temperature is maintained for a long time. It is not necessary to control the temperature more strictly than necessary.

The present invention is not limited only to the above-described embodiment, and various modifications can be made to the heating method of the rectangular pipe and the sleeve, and other various modifications can be made without departing from the gist of the present invention. Needless to say, it can be obtained.

[0032]

According to the first aspect of the present invention, the sleeve is pressed so as to bite the outside of the rectangular pipe, and the sleeve is firmly integrated with the rectangular pipe by shrink fitting to form a thick portion. Therefore, it is possible to efficiently manufacture a seamless steel column having a thick portion having excellent flatness and dimensional accuracy and having a seamless quality by welding together at a low cost.

Further, since the heating portion of the square pipe heats only up to the lower limit temperature of the temperature at which the crystal grains are coarsened, the crystal grains are not coarsened, and the sleeve is heated to the processing temperature at which the plastic deformation occurs. Press, so that the sleeve can be compression molded with a small pressing force, and after pressing, the sleeve is quenched to near the lower limit of the temperature at which the crystal grains are coarsened, thereby densifying the crystal grains. As a result, by performing slow cooling, stable quality free from the influence of composition change and residual stress can be obtained.

According to the second aspect of the present invention, the operation of pressing the sleeve using a pair of right-angle groove-shaped pressing dies facing each other, and subsequently rotating the square pipe by 90 ° and pressing the sleeve again is repeated. Therefore, the press forming operation of the sleeve can be easily performed.

[Brief description of the drawings]

FIG. 1 is a cut-away front view showing an example of a press device for forming a thick portion used in an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II of FIG.

FIG. 3 is a cut front view showing a state where the sleeve is pressed by the press device of FIG. 1;

FIG. 4 is a cut-away side view showing an example of a heating device for a sleeve.

FIG. 5 is a cut-away side view showing an example of a heating device for a square pipe.

FIG. 6 is a cut-away side view showing an example of the cooling device.

FIG. 7 is a sectional view taken along the line VII-VII of FIG. 6;

FIG. 8 is a block diagram showing a work process flow according to the embodiment of the present invention.

FIG. 9 is a diagram showing a form of a temperature condition when carrying out the present invention.

FIG. 10 is a sectional view of a steel column manufactured according to the present invention.

FIG. 11 is a schematic side view showing a conventional joint for connecting a steel column and a beam.

FIG. 12 is a cross-sectional view showing a thick portion formed in a rectangular pipe.

[Explanation of symbols]

2 square pipe 7 thick part 8 sleeve 9 and 10 press dies 9a, 10a perpendicular groove H heating unit T ₁ lower limit temperature T ₂ processing temperature

Claims (2)

[Claims] 1. A rectangular pipe and a rectangular short sleeve which can be fitted to the outside of the rectangular pipe, and a lower limit of a temperature at which crystal grains are coarsened in a range longer than a length of the sleeve at a required position of the rectangular pipe. While heating to near the temperature,
The sleeve is heated to a processing temperature at which the sleeve is plastically deformed, the sleeve is fitted to the heating part of the square pipe, and the sleeve is pressed from the outside using a press die so that the sleeve bites into the heating part of the square pipe. Forming a thick portion composed of a sleeve and a sleeve, and then cooling the heating portion in the thick portion from the inside so that the temperature becomes an intermediate temperature between the lower limit temperature of the temperature at which the crystal grains become coarse and the normal temperature, and crystallizes the sleeve. A method of manufacturing a steel column, comprising: quenching to a temperature near a lower limit of a temperature at which grains are coarsened, gradually cooling the material, and shrink-fitting the sleeve to a rectangular pipe by a temperature difference between a heating portion and the sleeve. 2. The method according to claim 1, wherein when the sleeve is pressed, the operation of pressing the sleeve using a pair of right-angle groove-shaped pressing dies facing each other, and then rotating the square pipe by 90 ° and pressing again is repeated. The method for producing a steel column according to claim 1.