KR101461834B1 - Apparatus and Method for Connecting Metal Pipe - Google Patents

Abstract

Disclosed are a device and a method for connecting a metal pipe used in a submarine pipeline. The disclosed metal pipe connection method includes a preparation step for preparing a tubular pin member where a first uneven portion is formed in a tapered outer circumferential surface and a tubular box member where a second uneven portion engaged with the first uneven portion is formed in a tapered inner circumferential surface; an overlap state for causing a surface contact between top portions of the first uneven portion and the second uneven portion by inserting the tubular pin member into the tubular box member; radial pressing step for pressing the tubular pin member in a radial direction; and a fastening step for moving the tubular pin member in an axial direction into the tubular box member to achieve complete engagement between the first uneven portion of the tubular pin member and the second uneven portion of the tubular box member. This metal pipe connection method enables mechanical pipeline fastening using simple structure.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to an apparatus and a method for connecting metal pipes used in a submarine pipeline.

The subsea pipeline is installed on the seabed to collect and transport hydrocarbon fluids such as crude oil and natural gas.

These pipelines are used by connecting metal pipes having a certain length (for example, 12 m) in series.

To this end, the pipeline is installed through a weld between the pipes on an offshore installation line. This marine welding method has an advantage that it can maintain the continuity of the material, but the work is performed in a shaking marine environment, so that stable processes such as a factory on the ground can not be carried out, and the strength of the usable material is limited. In addition, there is a problem that the usage fee of the installation line occupies a significant portion of the production cost of the submarine pipeline because the fee for use of the installation line used for marine welding is very expensive.

In recent years, development of deep-sea resources has been expanding due to depletion of mining resources in coastal regions. Therefore, there is an increasing need to use high-strength steels capable of coping with deep-sea water pressure and high-temperature / high-pressure resource environments. However, the hypothesis of the subsea pipeline using welding may deteriorate the fatigue performance due to the low fracture toughness of the welded portion.

In order to solve the problems of such welding work, a mechanical connection method using hydraulic pressure has been proposed.

U.S. Patent No. 4,648,627 discloses a tubular pin member having a tapered outer circumferential surface with concave and convex portions having protrusions and grooves and a tubular box member having a tapered inner circumferential surface with concave and convex portions engaged with the concave and convex portions of the tubular fin member And a method of fastening by hydraulic pressure.

In this method, first, the tubular pin member is inserted into the tubular box member, the protrusions of the irregular portion of the tubular fin member are fitted between the protrusions of the irregular portion of the tubular box member until the surface contact occurs, And to the space between the concave portion and the concave-convex portion of the tubular box member to thereby shrink the tubular fin member and induce the expansion of the tubular box member. In this state, when the tubular pin member and the tubular box member are pushed in the axial direction so that the tubular fin member can be completely inserted into the tubular box member, the grooves and projections of the concavo-convex portion of the tubular fin member are inserted into the projections and grooves of the concavo- The engagement is completed.

However, in the conventional method of connecting a metal pipe using hydraulic pressure, a high-pressure hydraulic pressure is supplied to a space between the concavo-convex portion of the tubular pin member and the concavo-convex portion of the tubular box member in a state in which the tubular pin member and the tubular box member are in contact with each other, Since the pin member is compressed and the tubular box member must be expanded, there is a problem that the facility becomes complicated due to the provision of the high-pressure hydraulic pressure supply unit.

Further, since a high pressure is required to be formed by the liquid supplied to the space between the concave-convex portion of the tubular pin member and the concave-convex portion of the tubular box member, it is necessary to seal the space to which the liquid is supplied. However, There is a problem that it is difficult to realize a complete sealing of the pressure space before the fastening, that is, during the fastening process.

Since the liquid supplied to the space between the tubular pin member and the concavo-convex portion of the tubular-shaped box member can leak into the inside of the tubular pin member and the recovery of the liquid after the completion of the hydraulic pressure supply operation is difficult, A considerable amount of liquid may remain in the space between the concavo-convex portions of the box member, and such residual liquid may adversely affect the performance of the metal pipe after completion of the fastening.

U.S. Patent No. 4,648,627 (issued October 3, 1987)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a connecting device and method of a metal pipe capable of mechanically connecting two pipes without welding or using oil pressure. do.

According to one aspect of the present invention, there is provided a tubular pin member having a tubular fin member having a first concavo-convex portion on a tapered outer circumferential surface, a tubular box member having a second concavo-convex portion on a tapered inner circumferential surface, ; An overlapping step of inserting the tubular pin member into the tubular box member to cause surface contact between the first concavo-convex portion and the normal portion of the second concavo-convex portion; A radial pressing step of radially pressing the tubular pin member; And a fastening step of causing the tubular pin member to axially move into the tubular box member so that the first concave-convex portion of the tubular fin member and the second concave-convex portion of the tubular box member are completely engaged with each other. to provide.

The radial pressing step may be configured to press the tubular pin member in the radial direction by inserting a pressure bar into the pressure hole formed through the outer circumferential surface of the tubular box member. At this time, the radial pressing step may be configured to press the tip portion of the tubular pin member or a portion of the first concavo-convex portion adjacent to the distal end portion with the pressing rod, The tubular pin member may be formed at a position corresponding to the tip end of the tubular fin member or a portion of the first concavoconvex portion adjacent to the tip end portion at a position where surface contact occurs between the normal portions of the second concavoconvex portion.

In order to provide a uniform radial pressing force, the pressing holes are formed at regular intervals of 2 to 6 on the outer circumferential surface of the tubular box member, and the radial pressing step includes pressing the tubular pin member It is possible to pressurize.

In addition, the fastening step may be performed together with the radial pressing step so that axial movement of the tubular pin member is facilitated.

The tubular pin member and the tubular box member are each formed with a protruding portion protruding in the axial direction, and a groove portion accommodating the tubular pin member and the protruding portion of the tubular box member is formed in the tubular box member and the tubular pin member And the coupling step is performed between the protruding part and the groove part so that the metal sealing is performed.

According to another aspect of the present invention, there is provided a metal pipe connection structure for connecting a tubular box member having a first concave-convex portion on a tapered outer circumferential surface thereof and a tubular box member having a second concave-convex portion on a tapered inner circumferential surface thereof, An axial pressing portion connected to the tubular pin member and an installation groove formed on an outer circumferential surface of the tubular box member to press the tubular fin member and the tubular box member in the axial direction; And a radial pressing portion that presses the tubular pin member in a radial direction by inserting a pressure bar into a pressing hole formed through an outer circumferential surface of the tubular box member.

At this time, the pressure holes may be formed at regular intervals of 2 to 6 on the outer circumferential surface of the tubular box member, and a plurality of the radial pressing portions may be arranged at predetermined intervals corresponding to the pressing holes.

In addition, the axial direction pressing portion may include a coupling member provided in the fitting groove portion of the tubular pin member and the tubular box member, respectively, and a hydraulic cylinder connected to the coupling member to provide an axial direction pressing force.

According to an embodiment of the present invention having such a configuration, the configuration of the device for mechanical connection of the pipeline is simple by moving the tubular pin member in the axial direction while radially pressing the tubular fin member through the radial pressing portion The effect can be obtained. In particular, by providing a plurality of radial pressing portions at regular intervals, the radial pressing force can be uniformly applied to the tubular pin member, and the axial direction fastening can be smoothly performed. Further, since the pipeline can be fastened through a simple mechanical pressing force, the effect of the present invention can be obtained that the working time can be greatly shortened.

In addition, according to the embodiment of the present invention, since the two pipes are not connected to each other by the marine welding, there is little restriction on the strength of the material used in the connection structure and the fatigue performance can be prevented from lowering due to the low fracture toughness . Particularly, since there is no limitation on the strength of the material, it is possible to use a high-strength steel material, so that the selection range of the drill ship and the installation line can be expanded by lightening and the effect of bonding high strength steel, alloy steel, titanium, .

Further, according to the embodiment of the present invention, it is possible to shrink the tubular pin member by the mechanical radial pressing force without using the hydraulic pressure and to mechanically connect the pipeline through the tubular pin member, There is no need for a separate sealing structure for forming the space, and the effect of preventing leakage and residual of the liquid for forming the hydraulic pressure can be obtained.

FIG. 1 is a perspective view showing a connection structure of a metal pipe used in a connecting device and a connecting method of a metal pipe according to the present invention, in which (a) is a perspective view showing a tubular pin member and a tubular box member, (B) is a front view showing the tubular pin member and the tubular box member in the coupled state.
FIG. 2 is a cross-sectional view of the tubular pin member and the tubular box member shown in FIG. 1, wherein (a) is a cross-sectional view showing an initial state of coupling, and FIG.
3 is an enlarged view of a portion "A" in Fig. 2 (a). Fig.
Fig. 4 is an enlarged cross-sectional view of a main portion of the joined state of Fig. 2 (b). Fig.
5 is a longitudinal sectional view showing a connecting device of a metal pipe according to an embodiment of the present invention.
Fig. 6 is a perspective view showing the operation of the pressurizing rod, and Fig. 6 (b) is a transverse sectional view showing the operating state of the radial pressing portion.
7 is a flowchart illustrating a method of connecting a metal pipe according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Further, the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. The shape and size of elements in the drawings may be exaggerated for clarity.

Furthermore, the singular forms "a", "an," and "the" include plural referents unless the context clearly dictates otherwise.

First, a connection method (S100) of a metal pipe used in an undersea pipeline according to one aspect of the present invention will be described with reference to FIGS. 1 to 7. FIG.

A method (S100) for connecting a metal pipe according to an aspect of the present invention is used in a submarine pipeline for drilling, production, and movement of crude oil or natural gas, and includes a tubular pin member (10) To connect the pipe.

7, a connection method S100 of a metal pipe according to an aspect of the present invention includes a step S110 of preparing a tubular fin member 10 and a tubular box member 20, 10 in a radial direction, a radial pressing step S130 for pressing the tubular fin member in the radial direction, and a step of pressing the tubular fin member 10 in the tubular box member 20 And a fastening step (S140) of fastening the tubular pin member (10) and the tubular box member (20) by moving the tubular pin member (10) in an axial direction to the inside of the tubular box member (20). When the fastening step A pressing force releasing step (S150) for releasing the axial pressing force can be performed.

1 and 2 (a), in step S110 of preparing the tubular fin member 10 and the tubular box member 20, the tubular fin member 10 having the first concave- (20) having a second concavo-convex portion (24) engaged with the first concavo-convex portion (14) on a tapered inner circumferential surface of the tubular box member (10). At this time, the outer peripheral surface of the tubular pin member 10 and the inner peripheral surface of the tubular box member 20 have substantially the same taper.

The tubular pin member 10 has a protruding portion 12 projecting axially on the inner side surface of the distal end portion 11 and an outer region where the protruding portion 12 is not formed on the distal end portion 11, (13).

The first concavo-convex portion 14 is formed on the outer circumferential surface spaced apart from the distal end portion 11 by a predetermined distance. The first concave-convex portion 14 has a structure in which protrusions and grooves are repeatedly engaged with the second concave-convex portion 24 of the tubular box member 20 described later. The first concavo-convex part 14 may be formed in a spiral shape so that it can be screwed to the second concavo-convex part 24 by rotation. However, the first concavo- It is possible to form the second concavo-convex portion 24 so as to be repeatedly engaged with the second concavo-convex portion 24. [

A groove 15 may be formed at a position spaced apart from the first concavo-convex part 14 by a predetermined distance to allow the projection 22 of the tubular box member 20 to be inserted therein. So that the engaging jaw portion 16 is formed.

The outer circumferential surface of the tubular pin member 10 may be formed with an installation groove 17 in which a mechanism for pressing the tubular pin member 10 in the axial direction is mounted. 18 are connected to a pipe P. At this time, the pipe (P) and the tubular pin member (10) can be integrated by a welding operation in the factory.

1 and 2 (a), the tubular box member 20 has a protruding portion 22 protruding in the axial direction on the inner surface of the distal end portion 21, and the protruding portion 22 is formed at the distal end portion 21, So that the outer region formed with no protruding portion 23 constitutes the leading end stopping portion 23.

A second concavo-convex portion (24) engaging with the first concavo-convex portion (14) is formed on an outer circumferential surface spaced apart from the distal end portion (21) by a predetermined distance. The second concave-convex portion 24 has a shape corresponding to the first concave-convex portion 14 and can be screwed to the first concave-convex portion 14 by rotation similarly to the first concave- But it is also possible that the protrusions and grooves forming the circular shape on the inner circumferential surface of the tubular box member 20 are formed to be repeated in the axial direction so as to be fitted to the first concave and convex portions 14.

The groove portion 25 may be formed at a position spaced apart from the second concavo-convex portion 24 by a predetermined distance. The outer side of the groove portion 25 may be a rear end stop Thereby forming a jaw portion 26. [

A pressing hole 30 is formed in the outer circumferential surface of the tubular box member 20 so as to press the tubular pin member 10 in the radial direction. It is preferable that 2 to 6 pressing holes 30 are formed so as to provide a pressing force in the radial direction around the tubular pin member 10. If the number of the pressing holes 30 is one, it is impossible to provide an appropriate pressing force to the tubular pin member 10. If the number of the pressing holes 30 is seven or more, many grooves are formed for forming the pressing holes 30, The strength of the substrate 10 is lowered.

Each of the pressing holes 30 may be formed at regular intervals so as to provide a uniform pressing force to the tubular pin member 10. For example, when three pressure holes 30 are formed, they may be installed every 120 degrees. When four pressure holes 30 are formed, they may be installed every 90 degrees.

The pressing hole 30 is located at a position adjacent to the tip 11 of the tubular pin member 10 or the first concave and convex portion 14 when the overlapping step S120 is performed, And can be formed at a corresponding position of the tubular box member 20 so as to be pressurized.

At this time, it is necessary that the pressurizing hole 30 does not have a size larger than necessary so as not to lower the strength of the tubular box member 20, and it is necessary that the pressurizing hole 30 (see FIG. 5 and FIG. 6) The length (31 in FIG. 5) and the vertical length (32 in FIG. 5) in which the pressure bar 131 can move in the vertical direction. That is, the transverse length 31 of the pressing hole 30 is formed so as to be slightly larger than the diameter of the pressing bar 131 (for example, 1.5 times the pressing bar diameter) The length of the pressing rod 131 may be determined in consideration of the length of the pressing rod 131 moving in the vertical direction and the diameter of the pressing rod 131 in the fastening step S140 described later.

The outer circumferential surface of the tubular box member 20 may be formed with an installation groove 27 in which a mechanism for pressing the tubular box member 20 in the axial direction is mounted. 28 are connected to a pipe P. At this time, the pipe P and the tubular box member 20 can be integrated by a welding operation in the factory.

Thus, the tubular pin member 10 and the tubular box member 20 are connected to the pipe P and used to join the adjacent pipe P.

2 (a) and FIG. 3, in the overlapping step S120, the protruding portion of the first concave-convex portion 14 of the tubular fin member 10 and the second concave-convex portion of the tubular box member 20 The tubular fin member 10 is inserted into the tubular box member 20 until the top portions (projections) of the tubular portion 24 contact each other.

That is, since the outer circumferential surface of the tubular pin member 10 and the inner circumferential surface of the tubular box member 20 are tapered, as shown in detail in FIG. 3, in the overlap S130 process, The portions 14 are not engaged with each other.

At this time, before the tubular pin member 10 and the tubular box member 20 are completely fastened, the first concave-convex part 14 and the second concave- The engaging protrusion 24a may be formed in the recessed and recessed portion 24 so as to be longer than the recessed portion. The engaging protrusion 24a may have a plurality of protrusions 24a formed in the region between the first recessed portion 14 and the second recessed portion 24 . Of course, the engaging protrusion 24a can be adjusted in position and shape so that engagement of the first concave-convex part 14 and the second concave-convex part 24 is not prevented in the finally engaged state.

5 and 6, in the radial pressing step S130, the pressing rod 131 is inserted into the pressing hole 30 formed through the outer circumferential surface of the tubular box member 20 to press the tubular pin member 10 And pressurized in the radial direction (FR).

At this time, in the radial pressing step S130, the first concavoconvex portion 14 of the tubular fin member 10 is contracted so that the axial movement of the tubular fin member 10 is facilitated, (11) or a portion of the first concave-convex portion (14) adjacent to the distal end portion (11) by the pressing rod (131). 5, it is also possible to press the distal end 11 adjacent to the free end of the tubular pin member 10, although it is shown that the first concavoconvex portion 14 is pressed in the radial pressing step S130.

As described above, the pressurizing holes 30 may be formed at regular intervals of 2 to 6 on the outer circumferential surface of the tubular box member 20 in order to provide a uniform pressing force to the tubular pin member 10, The pressing pin 131 may be inserted into each of the pressing holes 30 to press the tubular pin member 10 in the pressing step S130.

The fastening step S140 is a step of fastening the tubular pin member 10 so that the first concave-convex portion 14 of the tubular fin member 10 and the second concave-convex portion 24 of the tubular box member 20 are fully engaged with each other. And is moved into the tubular box member 20 in the axial direction FA.

It is preferable that the fastening step S140 is performed in a state in which the tubular pin member 10 is contracted, that is, in a state in which radial (FR) pressing force is applied, and may be performed together with the radial pressing step S130 . That is, the engaging step S140 may be performed simultaneously with the radial pressing step S130, and the radial pressing step S130 may be performed after a certain time has elapsed since the radial pressing step S130. Or may be performed in parallel. Specifically, as shown in FIG. 5, the pressing rod 131, which has been pressing the tubular pin member 10 at the position of the solid line circle at the upper portion of the pressing hole 30 at the beginning of the fastening step S150, Due to the movement of the member 10 in the axial direction FA, is changed to the position shown by the dotted line at the lower portion of the pressurizing hole 30 after completion of the fastening step S150.

As described above, in the engaging step S140, a pressing force is applied in the axial direction to move the tubular pin member 10 having the front end portion 11 and / or the first concavo-convex portion 14 contracted into the tubular box member 20 The radial compressive force applied to the outer circumferential surface of the tubular pin member 10 from the tubular box member 20 side due to the contact with the inner circumferential surface of the tubular box member 20 due to the insertion of the tubular pin member 10 in this process, The insertion of the tubular pin member 10 can be performed more easily. 4, the tubular pin member 10 and the tubular box member 20 can be inserted to the final engaging position of the first concave-convex portion 14 and the second concave-convex portion 24, as shown in Fig. 4 .

At this time, the fastening step S140 may move the tubular pin member 10 in the axial direction FA without rotating so that the first and second concave and convex portions 14 and 24 are completely engaged with each other.

When the tightening step S140 is completed, a pressing force releasing step S150 for releasing the radial pressing force and the axial pressing force is performed.

FIG. 2 (b) and FIG. 4 show a state in which the fastening is completed by the metal pipe connecting method (S100) according to the embodiment of the present invention.

The protruding portion 12 of the tubular fin member 10 is inserted into the groove portion 25 of the tubular box member 20 at the final engaging position and the protruding portion 12 of the tubular box member 20 22 are inserted into the groove 15 of the tubular pin member 10. [ At this time, the tip end stopping portion 13 of the tubular pin member 10 and the rear end stopping portion 26 of the tubular box member 20 come into contact with each other, and the rear end stopping portion 16 of the tubular fin member 10, The leading end stopping portion 23 of the protruding portion 20 is in contact with the protruding portion 12 to limit the insertion depth between the protruding portions 12 and 22 and the groove portions 15 and 25.

4, a metal sealing portion MS is formed between the protruding portions 12 and 22 and the groove portions 15 and 25 to form a metal sealing portion MS, The sealing between the members 20 can be realized. Specifically, an inner seal is formed between the protruding portion 12 of the tubular fin member 10 and the groove portion 25 of the tubular box member 20 by a metal sealing portion MS, An outer seal is formed between the metal seal portion MS and the groove portion 15 of the tubular pin member 10 so that a double seal region can be formed.

The engagement protrusions 13, 16, 23, and 26 around the protrusions 12 and 22 and the recesses 15 and 25 coupled to each other function to resist axial compressive force when installed on the sea floor.

Next, a connection apparatus 100 for a metal pipe according to an aspect of the present invention will be described with reference to FIG.

The connecting device 100 of the metal pipe is applicable to the tubular box member 20 and the tubular fin member 10 shown in Figs. 1 to 4, but is not limited thereto. That is, a tubular pin member 10 having a first concavo-convex portion 14 formed on a tapered outer circumferential surface, a second concavo-convex portion 24 formed on a tapered inner circumferential surface to be engaged with the first concavo-convex portion 14, 30, it is possible to connect the tubular pin member 10 and the tubular box member 20 using the connecting device 100 of the metal pipe according to the embodiment of the present invention.

6, the connecting device 100 of the metal pipe according to the embodiment of the present invention includes the tubular pin member 10 and the mounting grooves 17 and 27 formed on the outer peripheral surface of the tubular box member 20, An axial direction pressing portion 110 for pressing the tubular pin member 10 and the tubular box member 20 in the axial direction FA and a pressing hole 30 formed through the outer peripheral surface of the tubular box member 20, And a radial pressing portion 120 for pressing the tubular pin member 10 in the radial direction FR by inserting a pressure bar 131 into the tubular pin member 10.

The axial direction pressing portion 110 includes a locking member 112 provided in the fitting groove portions 17 and 27 of the tubular pin member 10 and the tubular box member 20, And a hydraulic cylinder 111 connected to the connecting member 113 via a connecting member 113 to provide a compressive force in the axial direction FA.

6 shows an example in which a plurality of hydraulic cylinders 111 are used. However, if a pressing force for inserting the tubular pin member 10 into the heated tubular box member 20 can be realized, It is also possible that one hydraulic cylinder 111 is used for the direction pressing portion 110. [

A plurality of radial pressing portions 120 may be arranged at predetermined intervals corresponding to the plurality of pressing holes 30. [ That is, although three radial pressing portions 120 are shown in Fig. 6, the radial pressing portion 120 is provided so as to be able to provide a radial pressing force around the tubular pin member 10, Two to six radial pressing portions 120 may be equally spaced around the tubular box member 20 in order to prevent the strength of the tubular box member 10 from significantly lowering.

The radial pressing portion 120 includes a pressing rod 131 which is inserted into the pressing hole 30 and provides a pressing force to the tubular pin member 10 in a radial direction FR and a pressing rod 131 for driving the pressing rod 131 And a driving member made of a hydraulic cylinder or the like.

5 (b), the radial pressing portions 120 are connected to each other by the connection frame 140 to move together when the axial (FA) movement of the tubular pin member 10 is made . Since the radial pressing portion 120 moves axially in a state in which the tubular pin member 10 is pressed, the connecting frame 140 can be configured to move together with the tubular pin member 10.

Meanwhile, the connection method (S100) of the metal pipe described above may be implemented through the connection device 100 of the metal pipe. However, the connecting device 100 of the metal pipe used in the connection method (S100) Is not limited to the embodiment shown in Fig.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art.

10 ... tubular pin member 11 ... tip end
12 ... protrusion 13 ... end stop jaw
14 ... First concave / convex portion 15 ... Groove
16 ... rear end stop portion 17 ... installation groove
18 ... rear end portion 20 ... tubular box member
21 ... front end portion 22 ... protruding portion
23 ... end stop jaw 24 ... second uneven portion
25 ... groove portion 26 ... rear end engaging jaw
27 ... installation groove 28 ... rear end
30 ... pressure hole
100 ... Connection device of metal pipe 110 ... Axial pressing part
111 ... hydraulic cylinder 112 ... engaging member
113 ... connection member 130 ... radial pressing portion
131 ... pressure rod 140 ... connection frame
MS ... Metal sealing part P ... Pipe

Claims (9)

A tubular fin member having a first concavo-convex portion formed on a tapered outer circumferential surface thereof, and a tubular box member having a second concavo-convex portion engaged with the first concavo-convex portion on a tapered inner circumferential surface thereof;
An overlapping step of inserting the tubular pin member into the tubular box member to cause surface contact between the first concavo-convex portion and the normal portion of the second concavo-convex portion;
A radial pressing step of radially pressing the tubular pin member; And
A fastening step of completely engaging the first concave-convex portion of the tubular pin member with the second concave-convex portion of the tubular box member by axially moving the tubular fin member into the tubular box member;
Wherein the metal pipe is a metal pipe. The method according to claim 1,
Wherein the radial pressing step presses the tubular pin member in a radial direction by inserting a pressure bar into a pressing hole formed through an outer circumferential surface of the tubular box member. 3. The method of claim 2,
Wherein the radial pressing step presses the distal end of the tubular pin member or a portion of the first concave-convex portion adjacent to the distal end portion with the pressing rod. 3. The method of claim 2,
Wherein the pressure hole is formed at an interval of 2 to 6 on the outer circumferential surface of the tubular box member,
Wherein the radial pressing step presses the tubular pin member through the respective pressure holes. 5. The method according to any one of claims 1 to 4,
Wherein the fastening step is performed with the radial pressing step. 5. The method according to any one of claims 1 to 4,
Wherein the tubular pin member and the tubular box member each have a protruding portion protruding in the axial direction and a groove portion for receiving the protruding portion of the tubular fin member and the tubular box member is formed in the tubular box member and the tubular fin member Lt; / RTI &
Wherein the coupling step is performed between the protruding part and the groove part so that the metal sealing is performed.
A connecting device for a metal pipe for joining a tubular pin member having a first concavo-convex portion formed on a tapered outer circumferential surface thereof and a tubular box member having a second concavo-convex portion engaged with the first concavo-convex portion on a tapered inner circumferential surface,
An axial direction pressing portion connected to the tubular pin member and an installation groove formed on an outer circumferential surface of the tubular box member to press the tubular fin member and the tubular box member in the axial direction; And
A radial pressing portion for radially pressing the tubular pin member by inserting a pressure bar into the pressing hole formed through the outer circumferential surface of the tubular box member;
And a connecting device for connecting the metal pipe. 8. The method of claim 7,
Wherein the pressure hole is formed at an interval of 2 to 6 on the outer circumferential surface of the tubular box member,
Wherein a plurality of radial pressing portions are disposed at regular intervals so as to correspond to the pressing holes. 9. The method according to claim 7 or 8,
Wherein the axial direction pressing portion includes a retaining member provided in the mounting groove portion of the tubular pin member and the tubular box member respectively and a hydraulic cylinder connected to the engaging member to provide an axial direction pressing force.

Images