JP2001150080A - Method and machine for partially enlarging wall thickness of pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for partially enlarging wall thickness of a pipe, protrudingly either on the inside or on the outside optionally. SOLUTION: The objective part of the pipe 1 is heated by the heater 35. By moving the pipe 1 along the length A, the objective part is held between the outer regulating means 41, opposing to the outside of the pipe 1, and the inner regulating means 51, opposing to the inside of the pipe 1b, so as to make a space S for enlargeing wall thickness at least on one side of the pipe. Then the thin enlarged wall thickness part 2a is formed by providing the pipe 1 with the pressure P along the length A. In moving the pipe 1 along the length A, heat press forming is repeated a plurality of times to form the thin enlarged wall thickness parts 2a-2n continuously, and the enlarged wall thickness part 2 of the specified length is formed. The enlarged wall thickness part 2 of the specified length can be formed projectingly either on the inside 1a or on the outside 1b, and the both sides of the pipe 1 by regulating the spaces causing enlarged wall thickness between the outer regulating means 41 and the inner regulating means 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a thickened portion for securing a plate thickness or the like at a beam connecting portion on a side of a column when connecting columns of a steel structure with beams. The present invention relates to a method for partially increasing the thickness of a pipe body and a facility for partially increasing the thickness of a pipe body, which is adopted in the above.

[0002]

2. Description of the Related Art Conventionally, a beam connecting portion on a column side is a beam penetrating system in which a column, that is, a square steel pipe is cut into a plurality of pieces in a longitudinal direction, and a groove is formed on each cut surface, and then a diaphragm is attached. However, according to this method, a large amount of time and cost is required for the cutting operation and the beveling operation, and there are problems that there are many welding points.

As a method of not cutting a rectangular steel pipe, for example, as shown in Japanese Patent Application Laid-Open No. Hei 7-238636, an inner diaphragm having a backing metal temporarily attached and welded to the periphery of both sides is inserted into the rectangular steel pipe. After the backing metal on the side of the insertion port is tack-welded to the inner wall of the square steel pipe, the through wall is used to weld the inner wall of the square steel pipe and the outer periphery of the inner diaphragm by electoslag welding. However, this method also required welding work.

In order to eliminate the need for a welding operation, for example, as disclosed in Japanese Patent Application Laid-Open No. H11-77151, a target portion of a pipe is heated, and then a longitudinal compressive force is applied to the pipe. After applying and forming a thickened portion at a target location and increasing the thickness, the pipe body and the forming roll means are relatively moved in the longitudinal direction of the pipe body, and the heated state of the heated state is formed by the forming roll means. A method for partially increasing the thickness of a tubular body for shaping the outer surface of a thickened portion is provided.

[0005]

However, according to the above-described thickening method, the thickened portion formed first is always projected outward from the outer surface of the pipe body. Forming roll means is required to align the outer surface of the body. Further, the heating means is moved by moving the heating means in the longitudinal direction of the tube. These can complicate the whole.

Accordingly, the present invention according to claim 1 of the present invention provides a method for forming a partially thickened portion of a pipe which can form the partially thickened portion by arbitrarily projecting the partially thickened portion from the outer surface of the inside of the tube. It is intended to provide. Another object of the present invention is to provide a pipe wall thickening facility capable of suitably realizing the pipe wall thickening method of the first aspect.

[0007]

In order to achieve the above-mentioned object, according to the present invention, a method for partially increasing the thickness of a tube according to the first aspect of the present invention comprises heating a target portion of the tube by a heating means. Then, the pipe body is moved in the longitudinal direction, and the heated portion is formed between at least one of the outer surface regulating means facing the outer surface of the tubular body and the inner surface regulating means facing the inner surface of the tubular body. After applying the compressive force in the longitudinal direction to the pipe, a short thickness increase part is formed at the heated location, and the heat compression molding is repeated several times while moving the pipe in the longitudinal direction to increase the short dimension. The present invention is characterized in that a partially thickened portion having a predetermined length is formed by continuously forming a meat portion.

Therefore, according to the first aspect of the present invention, the heating of the target portion by the heating means and the application of the compressive force are repeated a plurality of times while the tube body is reciprocated in the longitudinal direction, so that the short thickness increasing portion is continuously formed. To form a partially thickened portion having a predetermined length. At that time, the partially thickened portion is formed by the outer surface restricting means and the inner surface restricting means, thereby forming a gap for thickening. The inner and outer surfaces may be formed so as to protrude to one or both sides.

According to a second aspect of the present invention, there is provided a method for partially increasing the thickness of a tubular body, wherein a thin portion having a predetermined length or more is thickened by a plurality of times of heat compression molding. Thereafter, the heat-compression molding is repeated a plurality of times at least once for the thin-walled portion to form a partially-walled portion having a predetermined length. Therefore, according to the second aspect of the present invention, even if it is a thick part with a thickened portion, it is possible to easily perform the heat compression molding.

According to a third aspect of the present invention, there is provided a pipe wall thickening device, comprising: a support means capable of moving the pipe body in a longitudinal direction;
A compressive force applying means for applying a longitudinal compressive force to the tube supported by the support means, a heating means externally fitted to the tube supported by the support means, and a tube supported by the support means. An outer surface regulating means which is fitted to the outside and the outer surface regulating body can approach and separate from the outer surface of the tube, and an inner surface regulating means which is inserted into the tube supported by the supporting means and which can freely move toward and away from the inner surface of the tube. It is characterized by.

Therefore, according to the third aspect of the present invention, the heating of the target portion by the heating means and the application of the compressive force by the compressing force applying means are repeated a plurality of times while the tube is reciprocated in the longitudinal direction by the supporting means. Alternatively, the short-thickness thickened portion can be continuously formed to form a partially thickened portion with a predetermined length.
At that time, the outer surface regulating body of the outer surface regulating means is moved closer to and away from the outer surface of the tube, and the inner surface regulating body of the inner surface regulating means is moved closer to and away from the inner surface of the tube to arbitrarily increase the gap for increasing the thickness. By causing and restricting, the partially thickened portion can be formed so as to project to one or both sides with respect to the inner and outer surfaces of the tube.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
The state adopted for partially increasing the thickness of the square steel pipe will be described with reference to FIGS. In (a) of FIG. 9, as the square steel pipe 1 as an example of the pipe body, the thickness is 6 mm to 50.0 m.
m, diameter of 200 mm to 1000 mm, SM490
A, SM520B, SS400, SN400B, SN4
90B or the like is used. In such a square steel pipe 1, a certain range (or a plurality of locations) in the longitudinal direction A is set as a target partial thickening location. Then, by heating and compressing the partially thickened portion, a partially thickened portion 2 having a predetermined length L1 is formed as shown in FIG. 9B.

In FIG. 1 to FIG. 5, a partial wall thickening facility 10 for a pipe comprises a support means 11 capable of moving the square steel pipe 1 in the longitudinal direction A, and a square steel pipe 1 supported by the support means 11.
Force applying means 21 for applying a compressive force in the longitudinal direction A to the
A heating means 35 externally fitted to the square steel pipe 1 supported by the support means 11, and an external surface regulating body 42 externally fitted to the square steel pipe 1 supported by the support means 11
The inner surface restricting means 41 is inserted into the square steel pipe 1 supported by the supporting means 11, and the inner surface restricting body 60 is inserted into the square steel pipe 1 and supported by the supporting means 11.

The support means 11 includes, for example, a roller 12
The rectangular steel pipe 1 is supported by the supporting means 11 so that the longitudinal direction A is a lateral direction, and the rectangular steel pipe 1 is supported by the group so as to support the square steel pipe 1 in a transverse direction. It is configured to be moved (transported). The compressing force applying means 21 includes an end-side pressing device 22 that can freely oppose one end of the square steel pipe 1 in the longitudinal direction A.
And the other end side pressing device 30 which can freely oppose the other end side in the longitudinal direction A of the square steel pipe 1.

The one-end-side pressing device 22 is, for example, a driving bogie type, and is movable and reciprocable in the longitudinal direction A by being supported and guided on the floor rail side via wheels 23.
The front surface of the one end side pressing body 25 which is the front part of the movable body 24 is formed on one end side contact surface 26 with respect to one end surface of the square steel pipe 1. A through hole 27 is formed in the center of the one end side pressing body 25. The movable body 2
Numeral 4 is reciprocally movable in the longitudinal direction A by the operation of a driving device 28 mounted thereon and a cylinder device provided between the driving device 28 and the floor side.

The other end side pressing device 30 is, for example, of a hydraulic cylinder type, and has a front end of a piston rod body 31 movable in the longitudinal direction A, and a second end side pressing body 32 is provided. The front surface of 32 is formed on the other end side contact surface 33 with respect to the other end surface of the square steel pipe 1. The heating means 35 is provided between the one end pressing device 22 and the other end pressing device 30. The heating means 35 is a low-frequency heating furnace type, a medium-frequency heating furnace type, a high-frequency heating furnace type, or the like, and is set to a short heating length L2 in order to heat a target portion of the square steel pipe 1 from the outside. It is configured so that the square steel pipe 1 can be inserted.

The outer surface regulating means 41 is provided between the one end pressing device 22 and the heating means 35. The outer surface regulating means 41 has four outer surface regulating members 42 opposed to four sides of the square steel pipe 1, and these outer surface regulating members 42 are fixed to the front end of a piston rod body 43 of, for example, a hydraulic cylinder type. I have. When the group of piston rods 43 is extended, the outer surface regulating member 42 is brought close to the outer surface 1a of the square steel pipe and the adjacent edges are brought into contact with each other, so that the outer surface regulating member 42 is configured to have a square tubular shape as a whole. I have.

Here, the length L regulated by the outer surface regulating means 41 is shown.
Numeral 3 is set to be slightly longer than a predetermined length L1 of the target partial thickness increasing portion 2. Note that the outer surface regulating body 42 is detachable from the piston rod body 43 via a connecting member 44, and thus is configured to be replaceable according to the shape (outer dimension) of the square steel pipe 1. Further, the front and rear movement of each outer surface regulating body 42 is configured to be supported and guided by the guide device 45.

The inner surface restricting means 51 includes an outer surface restricting means 4.
1 are provided so as to be able to face each other. That is, the inner surface regulating means 51
Has a face plate 52 that can be inserted into the through hole 27, and a horizontal cylinder device 53 is fixed to the face plate 52. The piston rod 54 of the cylinder device 53 projects forward and along the longitudinal direction A, and a cam body 55 is fixed to an end of the piston rod 54.
The cam body 55 has a quadrangular shape, and a cam surface 56 formed by four outer surfaces is formed to have a larger inclined surface toward the front end.

At four locations in the circumferential direction on the front side of the face plate 52, there are provided slide members 58 which are supported and guided by guide structures 57 provided between the face plate 52 and are movable in and out. I have. The inside of the slide body 58 has a cam surface 59 inclined so as to be in contact with the cam surface 56.
In addition, an inner surface regulating body 60 is provided outside each slide body 58. Each slide body 58 is urged by an appropriate urging means so that the cam surface 59 comes into contact with the cam surface 56.

The cylinder device 53 includes a ground-side device 6
It is attached to the arm body 61 from 2. Here arm 6
1 is disposed along the longitudinal direction A, and is actuated by an operating device 63 provided on the ground-side device 62 side.
The inside thereof is provided with piping (not shown) to the cylinder device 53 and the like.

In the following, the action of increasing the thickness of the pipe body in the above embodiment will be described. First, as shown in FIG. 1, the square steel pipe 1 before the partial wall thickening is moved (loaded) from one end via a group of rollers 12 of the support means 11.
At the time of this movement, in the outer surface regulating means 41, as shown by the phantom line in FIG.
a, and the inner surface regulating means 5
In FIG. 1, as shown in FIG. 4, the inner surface regulating body 60 is located at a position separated from the inner surface 1b of the square steel pipe.

Therefore, the square steel pipe 1 to be moved is inserted into the heating means 35 and is moved by a predetermined amount, so that the intended place is connected to the heating means 35 as shown by the solid line in FIG. Stopped after facing. The stop position is accurately set as desired by controlling the movement by the support means 11 or by operating a stopper means (not shown).

In the state where the square steel pipe 1 is stopped in this way, a target portion (opposed portion) of the square steel pipe 1 is heated by the heating means 35. This heating is performed as local heating with a short heating length L2. After heating to a predetermined temperature, the square steel pipe 1 is moved again by the support means 11, whereby the square steel pipe 1 is inserted into the outer surface regulating means 41, and the inner surface regulating means 51 is inserted into the square steel pipe 1. You.

At this time, as shown in FIG. 3, the one end pressing device 22 is stopped at a predetermined position, so that one end of the square steel pipe 1 abuts on one end pressing surface 26 of the one end pressing body 25. As a result, the square steel pipe 1 is stopped at a predetermined position. Next, the piston rod body 43 group of the outer surface restricting means 41 is extended, and as shown in solid lines in FIGS. 4 and 5, the outer surface restricting member 42 comes close to and abuts the outer surface 1 a of the square steel pipe. The 42 group is made into a square tube shape as a whole by contacting adjacent edges.

The cylinder body 53 of the inner surface regulating means 51 is actuated before and after this, and the cam body 55 is moved integrally with the piston rod 54 which is contracted and moved, as shown in FIGS. Then, each slide body 58 is supported and guided by the guide structure 57 of the face plate 52 via the cam surface 56 and the cam surface 59 to be moved outward. Therefore, the inner surface regulating members 60 are moved outward together with the respective slide members 58 and approach the square steel tube inner surface 1b. Here, the approaching movement causes a gap S for thickening between the square steel tube inner surface 1b and the inner surface. And stopped. The gap S for thickening is set, for example, similarly to the thickness W of the square steel pipe 1.

In this state, the compressive force applying means 21 is operated to apply the compressive force P in the longitudinal direction A to the square steel pipe 1.
That is, the compression force P is applied by relatively moving the one end pressing body 25 and the other end pressing body 32 toward each other.
0 is moved closer, the one-end pressing device 22 is moved closer to the other-side pressing device 30,
2, 30 are moved closer to each other.

As shown by the imaginary lines in FIGS. 2 and 4, the heated portion is thickened inward by the compressive force, and the short thickened portion 2a is formed. At this time, the thickness of the heated portion is increased inward and outward by the compressive force, but the increase in the outward thickness is prevented by the outer surface regulating body 42 of the outer surface regulating means 41 being in contact with the outer surface 1a of the square steel pipe. Is done. Further, the increase in the thickness of the inner side is caused by the inner surface regulating body 60 of the inner surface regulating means 51.
And the inner wall 1b of the square steel pipe is filled so as to fill the gap S for thickening, and is abutted against the inner surface regulating body 60 to be regulated to form the short-thickness thickened portion 2a, and The inner surface of the short thickness increasing portion 2a is shaped.

In this manner, the short thickness increasing portion 2a is provided at one location.
Is formed in a ring shape, and the outer surface restricting body 42 of the outer surface restricting means 41 is separated from the outer surface 1a of the square steel pipe, and the inner surface restricting body 60 of the inner surface restricting means 51 is separated from the inner surface 1b of the square steel pipe. Thus, the other end pressing device 30 is moved away from the one end pressing device 22. Next, the square steel pipe 1 is moved (unloaded) in the opposite direction to that described above via the group of rollers 12 of the support means 11, and as shown in the phantom line in FIG. The movement of the square steel pipe 1 is stopped by making the part of the square steel pipe 1 face the heating means 35 as the next target part.

Thereafter, by performing heat compression molding in the same manner as described above, as shown in FIG. 6A, the next short thickness increasing portion 2b is connected to the next short thickness increasing portion 2a. Can be molded. In other words, the same heat compression molding is performed by forming the square steel pipe 1 in the longitudinal direction A.
By repeating the process a plurality of times while moving the workpiece, the short thickness increasing portions 2a, 2b, 2c to 2n can be continuously formed.
As shown in (b), a partial thickened portion 2 having a predetermined length can be formed. The partially thickened portion 2 is, for example, a square steel pipe 1
Is formed with the same thickness as the thickness W. Then, due to the formation of the partially thickened portion 2, the square steel pipe 1 is slightly shrunk.

As a result, as shown in FIG. 9 (b), the square steel pipe 1 is formed with a partially thickened portion 2 at the beam connecting portion, and the partially thickened portion 2 is directed outward from the outer surface 1a of the square steel pipe. The shape can be made uniform without being protruded. The square steel pipe 1 in which the intended partial thickening portion 2 has been formed as described above is carried out from the partial thickening equipment 10 and naturally cooled on a cooling floor or the like. Next, another wall-thickening action in the pipe wall-thickening facility of the present invention will be described with reference to FIG.

In performing the thickening action, each slide 5
8 together with the inner surface regulating body 60 group is moved out to approach the square steel pipe inner surface 1b, and a gap is formed between the inner surface regulating body 60 and the square steel pipe inner surface 1b to stop. For example, the thickness is set to half (thin thickness) with respect to the thickness W of the square steel pipe 1. In such a state, a thickening operation is performed in the same manner as described above, and first, as shown in FIG. 2Aa will be formed.
Next, by performing the heat compression molding in the same manner as described above, as shown in FIG. 7B, the next thin short-thickness thickened portion 2Ab can be formed continuously with the thin short-thickness thickened portion Aa. . Then, the same heat compression molding is repeated a plurality of times while moving the square steel pipe 1 in the longitudinal direction A, so that the thin short-thickness thickened portion 2 is formed.
Aa, 2Ab, and 2Ac to 2An can be continuously formed, and thus, as shown in FIG. 7C, a thin partial thickened portion 2A having a predetermined length or more can be formed.

Thereafter, by repeatedly performing the above-mentioned heat compression molding a plurality of times, as shown in FIG. 7 (d), a thin short thickened portion 2Ba is formed on the thin partially thickened portion 2A. Then, as shown in FIG. 7 (e), the next thin short thickness increasing portion 2Bb can be formed on the thin partial thickness increasing portion 2A and continuously with the thin short thickness increasing portion 2Ba. Then, the same heat compression molding is repeated a plurality of times while moving the square steel pipe 1 in the longitudinal direction A, so that the thin short-thickness thickening portions 2Ba, 2Bb, and 2Bc to 2B are formed on the thin partial thickening portions 2A.
Bn can be continuously formed, and as shown in (f) of FIG. 7, the partial thickened portion 2 having a predetermined length can be formed. Note that the partially thickened portion 2 is formed, for example, to have the same thickness as the thickness W of the square steel pipe 1. Then, due to the formation of the partially thickened portion 2, the thin partially thickened portion 2A is slightly shrunk.

In the above description, the heating and compression molding is repeatedly performed once on the thinned part 2A, but it may be performed a plurality of times in the same manner. The square steel pipe 1 which is a product obtained as described above is used for a column as shown in FIG. 8, for example, and when connecting the beam 65 to the partially thickened portion 2 as described above, Since the outer surface of the thickened portion 2 is uniform in external dimensions and smooth,
There is little gap between the two or a uniform and small gap, so that good welding (connection) can be performed, and further, welding accuracy and strength can be improved.

Next, another embodiment of the present invention will be described with reference to FIG. That is, a gap for thickening corresponding to half the thickness W of the square steel pipe 1 is generated between the outer surface regulating body 42 of the outer surface regulating means 41 and the outer surface 1a of the square steel pipe, and the inner surface regulating body 60 of the inner surface regulating means 51 is formed. By performing the desired heat compression molding in a state where a gap for thickening corresponding to half of the thickness W of the square steel pipe 1 is also generated between the square steel pipe 1 and the inner surface 1b of the square steel pipe, FIG. As shown in (1), the square steel pipe 1 can have a partially thickened portion 2 protruding from both the outer surface 1a of the square steel pipe and the inner surface 1b of the square steel pipe.

Further, the outer surface regulating body 42 of the outer surface regulating means 41
The desired heat compression molding is performed in a state in which a gap for thickening corresponding to the thickness W of the square steel pipe 1 is generated between the square steel pipe 1 and the outer surface 1a of the square steel pipe, as shown in FIG. 9D. Thus, the square steel pipe 1 in which the partially thickened portion 2 protrudes only from the outer surface 1a of the square steel pipe can be obtained. Next, still another embodiment of the present invention will be described with reference to FIG.

That is, as another example of the pipe, a round steel pipe 5 is used as shown in FIG. 10A, and the thickness, diameter, and material of the round steel pipe 5 are the same as those of the square steel pipe 1 described above. Have been. Then, the partially thickened portion 6 is formed in the same manner as described above. At this time, as shown in FIG. 10B, the round steel pipe 5 may have a partially thickened portion 6 protruding only from the inner surface 5b of the round steel pipe, and as shown in FIG. 10C. In addition, a round steel pipe 5 having a partially thickened portion 6 protruding from both sides of a round steel pipe outer surface 5a and a round steel pipe inner surface 5b may be formed. Further, as shown in FIG. The round steel pipe 5 may have a partially thickened portion 6 protruding only therefrom.

In each of the above-described embodiments, the partially thickened portions 2 and 6 are formed by heating and compression on the square steel pipe 1 and the round steel pipe 5. By subsequently heating the steel pipe 1 and the round steel pipe 5 as uniformly as possible by using a heating furnace or the like, the residual stress of the steel material and the deterioration of the material can be recovered, and the residual strain due to the heat of the steel material is eliminated. obtain.

In the above-described embodiment, the length of the partially thickened portions 2 and 6 in the longitudinal direction A is arbitrarily set, and the partially thickened portions 2 and 6 may be provided at one or more locations. Is formed. In the above-described embodiment, the partially thickened portion 2 is formed, for example, to have the same thickness as the thickness W of the square steel pipe 1, but this can be increased at an arbitrary ratio to the thickness W. Things.

[0040]

According to the first aspect of the present invention, while the tube is reciprocated in the longitudinal direction, the heating of the target portion by the heating means and the application of the compressive force are repeated a plurality of times to increase the short dimension. The meat portion can be continuously molded to form a partial thickness portion with a predetermined length, and at that time, the partial thickness portion is regulated by a thickness increasing gap by the outer surface regulating means and the inner surface regulating means, The inner and outer surfaces of the tube can be formed so as to protrude to one or both sides. Therefore, it is possible to form the partially thickened portion by arbitrarily projecting the partially thickened portion to the outer surface of the inside of the tube, and to simplify the entire structure by reciprocating the tube in the longitudinal direction. Can be provided.

According to the second aspect of the present invention,
Even if it is a thick part with a thickened part, it can be heated and compressed without difficulty. According to the third aspect of the present invention, the heating of the target portion by the heating means and the application of the compressive force by the compressing force applying means are repeated a plurality of times while the tube is reciprocated in the longitudinal direction by the supporting means. In addition, it is possible to form the partial thickened portion having a predetermined length by continuously forming the short thickness thickened portion. At that time, the outer surface regulating body of the outer surface regulating means is moved closer to and away from the outer surface of the tube, and the inner surface regulating body of the inner surface regulating means is moved closer to and away from the inner surface of the tube to arbitrarily increase the gap for increasing the thickness. By causing and restricting, the partially thickened portion can be formed so as to project to one or both sides with respect to the inner and outer surfaces of the tube. Thereby, the method for partially increasing the thickness of the tubular body according to claim 1 can be suitably realized.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a partially cut-away side view at the time of a heating action in a facility for partially increasing the thickness of a tubular body.

FIG. 2 is a partially cutaway side view of the pipe body in a partial thickening facility during a thickening operation.

FIG. 3 is a partially cut-away side view when the inner and outer regulating means in the partial thickening facility of the pipe are separated from each other.

FIG. 4 is a partially cutaway side view of the inner and outer regulating means in the partial thickening facility of the pipe when approaching.

FIG. 5 is a partially cutaway front view of the inner and outer regulating means in the partial wall-thickening facility of the pipe when approaching.

6A and 6B are views showing a thickening action of a partial wall thickening facility of the pipe body, in which FIG. 6A is a vertical sectional side view of a main part in the middle of thickening, and FIG. is there.

FIGS. 7A and 7B show another thickening action in the partial thickening facility of the pipe body, wherein FIG. 7A is a longitudinal sectional side view of a main part at the start of thinned thickening, and FIG. Longitudinal side view of the part,
(C) is a vertical cross-sectional side view of the main part at the end of the thinned part,
(D) is a vertical cross-sectional side view of the main part at the beginning of the repeated thickening on the thin part thickening part, (e) is a vertical cross-sectional side view of the main part during the repeated thickening on the thin part thickening part, ( (f) is a longitudinal sectional side view of the main part at the end of the repeated thickening on the thin partial thickening part.

FIG. 8 is a vertical cross-sectional view showing a state in which a square steel pipe obtained by a partial thickening facility for the pipe is used for a column.

9A and 9B show various square steel pipes according to an embodiment of the present invention and another embodiment. FIG. 9A is a partially cutaway perspective view of a square steel pipe before thickening, and FIG. A partially cutaway perspective view of a square steel pipe having a partially thickened portion, (c) is a partially cutaway perspective view of a square steel pipe having a partially thickened portion protruding on both the inner and outer sides, and (d) is a projection only on the outer side. FIG. 4 is a partially cutaway perspective view of a square steel pipe having a partially thickened portion to be formed.

FIGS. 10A and 10B show various round steel pipes according to still another embodiment of the present invention, wherein FIG. 10A is a partially cutaway perspective view of the round steel pipe before thickening, and FIG. A partially cutaway perspective view of a round steel pipe having a portion formed therein, (c) is a partially cutaway perspective view of a round steel pipe having a partially thickened portion protruding on both the inner and outer sides,
(D) is a partially cutaway perspective view of a round steel pipe having a partially thickened portion protruding only outside.

[Explanation of symbols]

 Reference Signs List 1 square steel pipe (tube body) 1a square steel pipe outer surface (tube outer surface) 1b square steel tube inner surface (tube inner surface) 2 partially thickened portion 2a to 2n short thickened portion 2A thin partially thickened portion 2Aa to 2An thin short Thickening part 2Ba to 2Bn Thin short-thickness thickening part 5 Round steel pipe (tube body) 5a Round steel pipe outer surface (tube outer surface) 5b Round steel pipe inner surface (tube inner surface) 6 Partial thickening part 10 Partial thickening equipment 11 Support means DESCRIPTION OF SYMBOLS 21 Compressive force giving means 22 One end side pressing device 25 One end side pressing body 26 One end side abutting surface 30 The other end side pressing device 32 The other end side pressing body 33 The other end side abutting surface 35 Heating means 41 External surface regulating means 42 External surface regulation Body 51 Inner surface regulating means 52 Face plate 53 Cylinder device 55 Cam body 57 Guide structure 58 Slide body 60 Inner surface regulating body 65 Beam material A Longitudinal direction of pipe L1 Predetermined length of partial thickening portion 2 L2 Heating length by heating means 35 The thickness S thickening for clearance P compressive force of the regulating length W tube according L3 outer surface regulating means 41

Claims (3)

[Claims] 1. A heating means heats a target portion of a tube body, and then moves the tube body in a longitudinal direction so that the heated portion is opposed to an outer surface regulating means facing an outer surface of the tube and an inner surface thereof. Between the inner surface regulating means and at least one of them, a gap for thickening is formed and positioned, and then a compressive force in the longitudinal direction is applied to the tubular body to form a short thickened portion at a heated portion, and the tubular body is formed. Is formed by repeating heating and compression molding a plurality of times while moving in the longitudinal direction to continuously form a short thickness thickened portion, thereby forming a partially thickened portion having a predetermined length. Meat way. 2. After a plurality of heat compression moldings are performed to increase the thickness of a thin portion having a predetermined length or more, a plurality of heat compression moldings are repeatedly performed at least once on the thin portion. 2. The method according to claim 1, further comprising forming a partially thickened portion having a predetermined length. 3. A supporting means capable of moving the tube in the longitudinal direction, a compressing force applying means for applying a compressive force in the longitudinal direction to the tube supported by the supporting means, and a tube supported by the supporting means. Heating means externally fitted to the outer surface of the tube, outer surface restricting means externally fitted to the tube supported by the supporting means, the outer surface regulating body being able to approach and separate from the outer surface of the tube, and inner surface inserted into the tube supported by the supporting means A wall thickening device for a tubular body, wherein the regulating body comprises inner surface regulating means which can be freely moved toward and away from the inner surface of the tubular body.