JP2014030842A - Welded joint for high strength steel pipe, manufacturing method of the same, joining method of high strength steel pipe, and junction structure of high strength steel pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welded joint for high strength steel pipes which is capable of easily and reliably welding and joining high strength steel pipes together by using weld metal having lower strength than the high strength steel pipes, and a junction structure of the high strength steel pipes.SOLUTION: One high strength steel pipe 20 and the other high strength steel pipe 25 are arranged so that an inclined face 11 of a welded joint 10 of the one high strength steel pipe 20 faces an end face of the other high strength steel pipe 25, and thereby a bevel section 45 is provided between the inclined face 11 and the end face. By filling up the bevel section 45 with weld metal 50 having lower strength than the high strength steel pipes 20 and 25, the high strength steel pipes 20 and 25 are welded to be joint.

Description

  The present invention relates to a joint for high-strength steel pipes, a method for manufacturing the joint, a method for joining high-strength steel pipes, and a joining structure.

Generally, a so-called overmatching joint that uses a welding material having higher strength than a high-strength steel pipe is employed as a welded joint that transmits the total strength of the high-strength steel pipe. However, in order to realize an overmatching joint that exceeds the strength of a high-strength steel pipe made of an ultra-high strength material of 800N to 1000N class, a very expensive high-strength welding material is used.
Further, in welding using such a high-strength welding material, since it is necessary to strictly manage the prognostic heat, application to building structures that require on-site welding is greatly limited. In addition, since the welding heat input and the temperature between welding passes are more severe than those of low-strength welding materials, work efficiency is also reduced.

On the other hand, so-called undermatching joints, which lower the strength of weld metal than the strength of high-strength steel pipes, are lower in cost, compared to overmatching joints that use high-strength welding materials, with prognostic heat management and welding heat input / There is an advantage that welding with relaxed conditions such as interpass temperature can be performed.
The thing of patent document 1 is known as an example of the welding metal for under matching. The weld metal for undermatching is characterized in that the hardness (Hv) is 210 or less and the crystal grain size of the weld metal is 8 μm or less in terms of the equivalent circle diameter.

JP 2005-305514 A

  By the way, although the hardness, crystal grain size, etc. of a weld metal are indicated by the said patent document 1, when joining high strength steel pipes using such a weld metal whose strength is lower than a high strength steel pipe. However, it is not disclosed what kind of welded joint is used, and what kind of joining method and joining structure are used.

  Therefore, the present invention provides a welded joint for high-strength steel pipes that can be easily and reliably welded and joined to each other with a weld metal having a lower strength than the high-strength steel pipes, a method for producing a welded joint for high-strength steel pipes, It aims at providing the joining method of a steel pipe, and the joining structure of a high-strength steel pipe.

In order to achieve the above object, a welded joint for high-strength steel pipe according to the present invention is formed at the end of a high-strength steel pipe, and welds and joins the high-strength steel pipe to another high-strength steel pipe in the axial direction. Welded joint for high strength steel pipe,
On the inner peripheral surface of the end portion of the high-strength steel pipe, a reinforcing ring having a lower strength than the high-strength steel pipe is welded to the high-strength steel pipe with a weld metal having a lower strength than the high-strength steel pipe,
An annular inclined surface extending from the outer peripheral surface of the end portion of the high-strength steel pipe to at least the weld metal toward the reinforcing ring is tapered on the end portion side of the high-strength steel pipe. And

In the present invention, when one high-strength steel pipe having a weld joint for high-strength steel pipe is joined to the other high-strength steel pipe in the axial direction, one high-strength steel pipe and the other high-strength steel pipe are A groove portion can be provided between the inclined surface and the end surface by disposing the inclined surface of the welded joint for high-strength steel tube of the high-strength steel tube so that the end surface of the other high-strength steel tube faces the other. .
Therefore, by filling the groove with a weld metal having a strength lower than that of the high-strength steel pipe, the weld metal is provided between the inclined surface of one high-strength steel pipe and the end face of the other high-strength steel pipe and at least a reinforcing ring. Since the weld metal is welded, both the high-strength steel pipes and at least the weld metal of the reinforcing ring can be integrally welded by the weld metal. Therefore, both high-strength steel pipes can be easily and reliably welded and joined.

In this way, it is possible to use a weld metal having a strength lower than that of a high-strength steel pipe, so that the prognostic heat treatment can be omitted and the restriction on the temperature between passes can be relaxed.
Further, since the reinforcing ring has lower strength than the high-strength steel pipe, it is easy to process and weld to the high-strength steel pipe.
In addition, by forming the inclined surface in advance in a factory on a high-strength steel pipe having a reinforcing ring, a groove portion is formed simply by facing or abutting high-strength steel pipes to be joined on site. The Therefore, there is no need for on-site groove processing, and the work of construction can be saved accordingly.

The method for producing a welded joint for high-strength steel pipe according to the present invention is as follows.
On the inner peripheral surface of the end portion of the high-strength steel pipe, a reinforcing ring having a strength lower than that of the high-strength steel pipe is used so that one end face thereof is substantially flush with the end face of the high-strength steel pipe. Welding with a weaker weld metal,
Next, the end portion of the high-strength steel pipe is cut off so that the end side of the high-strength steel pipe extends from the outer peripheral surface of the end portion of the high-strength steel pipe toward the reinforcement ring to at least the weld metal. The annular inclined surface is formed on the part side.

  In the present invention, the annular inclined surface can be formed on the end side of the high-strength steel pipe by cutting off the end side of the high-strength steel pipe to which the reinforcing ring is welded. Therefore, the high-strength steel pipe can be easily formed. Welded joints can be manufactured.

The method for joining high-strength steel pipes of the present invention is a method for joining high-strength steel pipes in which one high-strength steel pipe having a welded joint for high-strength steel pipes and the other high-strength steel pipe are welded and joined in the axial direction. And
The one high-strength steel pipe and the other high-strength steel pipe are arranged so that the inclined surface of the weld joint for the high-strength steel pipe of the one high-strength steel pipe and the end surface of the other high-strength steel pipe face each other. By providing a groove portion between the inclined surface and the end surface,
Next, the groove portion is filled with a weld metal having a strength lower than that of the high-strength steel pipe to weld and join the high-strength steel pipes.

  In the present invention, the weld metal is filled between the inclined surface of one high-strength steel pipe and the end face of the other high-strength steel pipe by filling the groove with a weld metal having a lower strength than the high-strength steel pipe. Since it reaches even the weld metal which welds the ring, the weld metal of both high strength steel pipes and at least the reinforcement ring can be integrally welded by the weld metal. Therefore, both high-strength steel pipes can be easily and reliably welded and joined.

Further, in the above configuration of the present invention, the one high-strength steel pipe and the other high-strength steel pipe are connected to the inclined surface of the weld joint for the high-strength steel pipe of the one high-strength steel pipe and the other high-strength steel pipe. When placing it so that it faces the end face,
In advance, on the inner peripheral surface of the end portion of the other high-strength steel pipe, a reinforcing ring having a lower strength than the high-strength steel pipe so that one end face thereof is substantially flush with the end face of the other high-strength steel pipe, It is preferable to weld with a weld metal having a lower strength than the other high-strength steel pipe.

  According to such a configuration, one high-strength steel pipe and the other high-strength steel pipe are connected to the inclined surface of the weld joint for the high-strength steel pipe of the one high-strength steel pipe and the end surface of the other high-strength steel pipe. When a groove portion is provided between the inclined surface and the end surface by disposing them so as to face each other, the back side of the groove portion is formed by a reinforcing ring welded to both high-strength steel pipes. Since it is obstruct | occluded, welding metal can be spread over the depth of a groove part, and welding can be made more reliable.

The high strength steel pipe joining structure of the present invention is a high strength steel pipe joining structure formed by welding one high strength steel pipe having a weld joint for high strength steel pipe and the other high strength steel pipe in the axial direction. Because
The one high-strength steel pipe and the other high-strength steel pipe are arranged such that the inclined surface of the weld joint for the high-strength steel pipe of the one high-strength steel pipe and the end surface of the other high-strength steel pipe face each other. By arranging, a groove portion is provided between the inclined surface and the end surface,
The high-strength steel pipes are welded and joined by filling the groove with a weld metal having a strength lower than that of the high-strength steel pipes.

  In the present invention, the weld metal is filled between the inclined surface of one high-strength steel pipe and the end face of the other high-strength steel pipe by filling the groove with a weld metal having a lower strength than the high-strength steel pipe. Since it reaches even the weld metal which welds the ring, the weld metal of both high strength steel pipes and at least the reinforcement ring can be integrally welded by the weld metal. Therefore, both high-strength steel pipes can be easily and reliably welded and joined.

In the configuration of the present invention, a reinforcing ring having a lower strength than the high-strength steel pipe is provided on the inner peripheral surface of the end of the other high-strength steel pipe, and one end face thereof is substantially the same as the end face of the other high-strength steel pipe. It is welded by a weld metal having a lower strength than the other high-strength steel pipe so as to be flush with each other,
It is preferable that the reinforcing ring welded to the one high strength steel pipe and the reinforcing ring welded to the other high strength steel pipe are in contact with each other.

  According to such a configuration, since the back side of the groove portion is closed by the reinforcing ring welded to both high-strength steel pipes, the weld metal is spread to the back of the groove portion to ensure welding. It can be.

  According to the present invention, high-strength steel pipes can be welded and joined easily and reliably with a weld metal having a lower strength than the high-strength steel pipes. Therefore, it is possible to use a weld metal having a strength lower than that of the high-strength steel pipe, and it becomes possible to omit the prognostic heat treatment and relax the restriction on the interpass temperature.

It is for demonstrating the process of the manufacturing method of the welded joint for high strength steel pipes concerning embodiment of this invention, and is sectional drawing which shows the state before inserting a reinforcement ring in a high strength steel pipe. It is sectional drawing which shows the state which inserted the reinforcement ring in the same high strength steel pipe. It is sectional drawing which shows the state which welded the reinforcement ring to the high strength steel pipe. It is sectional drawing which shows an example of the welded joint for high strength steel pipes concerning embodiment of this invention. It is other example sectional drawing which shows the welded joint for high-strength steel pipes concerning embodiment of this invention. It is for demonstrating the process of the joining method of the high strength steel pipe which concerns on embodiment of this invention, and is sectional drawing which shows the state which has arrange | positioned the high strength steel pipes facing each other. FIG. 3 is a cross-sectional view showing a state in which high strength steel pipes are arranged with their reinforcing rings abutting each other. It is sectional drawing which shows an example of the joining structure of the high strength steel pipe which concerns on embodiment of this invention. It is sectional drawing which shows the other example of the joining structure of the high strength steel pipe which concerns on embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
First, the structure of the welded joint for high strength steel pipes according to the present invention will be described.
FIG. 1D is a cross-sectional view showing an example of a welded joint for high-strength steel pipe (hereinafter abbreviated as a welded joint). The welded joint 10 is formed on the end side of the high-strength steel pipe 20, and is used for welding the high-strength steel pipe 20 to another high-strength steel pipe 25, which will be described later, by welding in the axial direction. The high-strength steel pipes 20 and 25 are used as pillars of structures such as buildings, and are actually long steel pipes in the vertical direction, but in FIGS. 1A to 1E and FIGS. 2A to 2D, the end portions thereof are used. Only listed.

The high-strength steel pipe 20 is formed in a cylindrical shape, and its strength (tensile strength) is about 780 to 1100 MPa.
On the inner peripheral surface of the end of the high strength steel pipe 20 (the upper end in FIG. 1D), a reinforcing ring 30 having a lower strength than the high strength steel pipe 20 is formed by the weld metal 40 having a lower strength than the high strength steel pipe 20. 20 and coaxially welded. The strength (tensile strength) of the reinforcing ring 30 is about 490 to 740 MPa, and the strength of the weld metal 40 is about 490 to 780 MPa.

On the end portion side of the high-strength steel pipe 20, an annular inclined surface 11 is formed from the outer peripheral surface of the end portion of the high-strength steel pipe 20 toward the reinforcing ring 30 and beyond the weld metal 40 to the upper end of the reinforcing ring 30. ing.
The inclined surface 11 includes an inclined surface 20 a at the upper end of the high-strength steel pipe 20, an inclined surface 40 a formed at the upper part of the weld metal 40, and an inclined surface 30 a formed at the upper end portion of the reinforcing ring 30.

The high-strength steel pipe 20 having the weld joint 10 as described above is manufactured as follows.
That is, first, as shown in FIG. 1A, a reinforcing ring 30 is prepared. The reinforcing ring 30 is a frustoconical ring and is formed of a material having a lower strength than the high-strength steel pipe 20. Further, the diameter of the maximum outer diameter of the reinforcing ring 30 is substantially equal to or slightly smaller than the inner diameter of the high-strength steel pipe 20.

  Next, as shown in FIG. 1B, the reinforcing ring 30 is placed inside the high-strength steel pipe 20, and one end face (the upper end face in FIG. 1A) is substantially the same as the end face (the upper end face in FIG. 1A). It arrange | positions so that it may become flush | level and may become coaxial with the said high strength steel pipe 20. As a result, an annular groove 12 having a triangular cross section is formed between the inner peripheral surface of the high-strength steel pipe 20 and the outer peripheral surface of the reinforcing ring 30.

  The thickness (plate thickness) of the high-strength steel pipe 20 is t, the plate thickness of the reinforcement ring 30 (distance between both end faces of the reinforcement ring 30) is tb, the yield strength of the high-strength steel pipe 20 is F, and the reinforcement ring 30. T, tb, F, and Fb are set so as to satisfy F · t ≦ Fb (t + tb).

  Next, as shown in FIG. 1C, the groove 12 is filled with a weld metal 40, and the reinforcing ring 30 is welded and fixed to the inner peripheral surface of the high-strength steel pipe 20. This welding is performed by arc welding or the like, and a welding material having a strength lower than that of the high-strength steel pipe 20 is used as a welding material.

Next, as shown in FIG. 1D, the end side of the high-strength steel pipe 20 is moved from the outer peripheral surface of the end of the high-strength steel pipe 20 toward the upper end surface of the reinforcing ring 30, beyond the weld metal 40, Cut up to the top surface.
For example, the upper portions of the high-strength steel pipe 20, the weld metal 40, and the reinforcing ring 30 are integrally cut off along a cutting line C1 indicated by a two-dot chain line in FIG. 1C. The cutting line C <b> 1 is set so as to connect the upper end of the inner periphery of the reinforcing ring 30 from a predetermined position on the outer periphery of the high-strength steel pipe 20.
Thus, the annular inclined surface 11 is formed on the end portion side (the upper end portion side in FIG. 1D) of the high strength steel tube 20 by cutting off the end portion side of the high strength steel tube 20 along the cutting line C1.

  Since the annular inclined surface 11 can be formed on the end side of the high-strength steel pipe 20 by cutting off the end side of the high-strength steel pipe 20 to which the reinforcing ring 30 is welded in this way, a welded joint can be easily formed. 10 can be manufactured.

In the present embodiment, the end side of the high-strength steel pipe 20 to which the reinforcing ring 30 is welded is cut off along the cutting line C1, but may be cut off along the cutting line C2 as shown in FIG. 1C. That is, the end side of the high-strength steel pipe 20 may be cut off so as to reach the upper surface of the weld metal 40 from the outer peripheral surface of the end of the high-strength steel pipe 20 toward the reinforcing ring.
By cutting off in this way, a welded joint 15 having an inclined surface 14 as shown in FIG. 1E on the end side of the high-strength steel pipe 20 can be manufactured. The inclined surface 14 is constituted by an inclined surface 20 b at the tip of the high-strength steel pipe 20 and an inclined surface 40 b formed on the top of the weld metal 40.

Next, the joining method and joining structure of the high strength steel pipe concerning the present invention are explained.
In the present embodiment, one high-strength steel pipe 20 having the weld joint 10 and the other high-strength steel pipe 25 are joined in the axial direction as follows.

  That is, first, as shown in FIG. 2A, a reinforcing ring 35 having a strength lower than that of the high-strength steel pipe 25 is provided on one end face in advance on the inner peripheral surface of the other high-strength steel pipe 25 (lower end in FIG. 2A). It welds with the weld metal 40 whose intensity | strength is lower than the other high strength steel pipe 25 so that (the lower end surface in FIG. 2A) may become substantially flush with the lower end face of the other high strength steel pipe 25. Note that the strength (tensile strength) of the high-strength steel pipe 25 is set to a value substantially equal to that of the high-strength steel pipe 20.

Next, the one high-strength steel pipe 20 and the other high-strength steel pipe 25 are arranged such that the inclined surface 11 of the weld joint 10 of the one high-strength steel pipe 20 and the end face 25a of the other high-strength steel pipe 25 face each other. ,Deploy.
Next, as shown in FIG. 2B, the reinforcing rings 30 and 35 of both the high-strength steel pipes 20 and 25 are applied coaxially, that is, by bringing the reinforcing rings 30 and 35 into contact with each other, A groove portion 45 is provided between the inclined surface 11 of the high-strength steel pipe 20 and the lower end surface 25 a of the other high-strength steel pipe 25.

  Next, as shown in FIG. 2C, the groove portion 45 is filled with a weld metal 50 having a strength lower than that of the high-strength steel pipes 20 and 25, thereby welding and joining the high-strength steel pipes 20 and 25 together. . This welding is performed by arc welding or the like on site. The strength of the weld metal 50 is about 490 to 780 MPa.

  In the high strength steel pipes 20 and 25 joined in this way, a groove 45 is provided between the inclined surface 11 of the weld joint 10 of one high strength steel pipe 20 and the end face 25a of the other high strength steel pipe 25. Thus, a joining structure in which the groove 45 is filled with the weld metal 50 is obtained.

  In this way, by filling the groove portion 45 with the weld metal 50 having a lower strength than the high strength steel pipes 20 and 25, the weld metal 50 has the inclined surface 11 of the one high strength steel pipe 20 and the other high strength steel pipe 25. Between the end faces 25a, between the reinforcing rings 30, 35 and between the weld metals 40, 40, the high-strength steel pipes 20, 25, the reinforcing rings 30, 35 and the weld metals 40, 40 are connected by the weld metal 50. Can be welded together. Therefore, both the high strength steel pipes 20 and 25 can be welded and joined easily and reliably.

Thus, it becomes possible to use the weld metal 50 having a lower strength than the high-strength steel pipes 20 and 25, and it becomes possible to omit the prognostic heat treatment and relax the restriction on the temperature between passes.
Furthermore, since the reinforcement rings 30 and 35 are lower in strength than the high-strength steel pipes 20 and 25, they can be easily processed and welded to the high-strength steel pipes 20 and 25.
In addition, by forming the inclined surface 11 in advance in the factory on the high-strength steel pipe 25 having the reinforcing ring 30, the high-strength steel pipes 20, 25 to be joined at the site are simply faced to face each other, A groove 45 is formed. Therefore, there is no need for on-site groove processing, and the work of construction can be saved accordingly.

In the present embodiment, when the high strength steel pipes 20 and 25 are welded and joined, the reinforcing ring 35 is welded to the inner peripheral surface of the end of the other high strength steel pipe 25 in advance by the weld metal 40. However, the reinforcing ring 35 may not be welded to the high-strength steel pipe 25.
In this case, as shown in FIG. 2D, one high-strength steel pipe 20 and the other high-strength steel pipe 25 are composed of the inclined surface 11 of the weld joint 10 of one high-strength steel pipe 20 and the end face 25a of the other high-strength steel pipe 25. Are arranged so as to face each other, so that a groove portion 46 is provided between the inclined surface 11 and the end surface 25a, and the weld metal having lower strength than the high-strength steel pipes 20 and 25 is provided in the groove portion 46. By filling 50, both high strength steel pipes 20 and 25 are welded and joined.
Accordingly, the weld metal 50 reaches between the inclined surface 11 of one high-strength steel pipe 20 and the end surface 25a of the other high-strength steel pipe 25 and to the top surfaces of the weld metal 40 and the reinforcing ring 30. The high-strength steel pipes 20, 25, the reinforcing ring 30, and the weld metal 40 can be integrally welded. Therefore, even in this case, both the high-strength steel pipes 20 and 25 can be easily and reliably welded and joined.

10, 15 Welded joints 11 and 14 for high-strength steel pipes Inclined surfaces 20 and 25 High-strength steel pipes 30 and 35 Reinforcing rings 45 and 46 Grooves 40 Weld metal 50 Weld metal

Claims (6)

A welded joint for high-strength steel pipes, formed at the end of a high-strength steel pipe, for welding the high-strength steel pipe to another high-strength steel pipe in the axial direction,
On the inner peripheral surface of the end portion of the high-strength steel pipe, a reinforcing ring having a lower strength than the high-strength steel pipe is welded to the high-strength steel pipe with a weld metal having a lower strength than the high-strength steel pipe,
An annular inclined surface extending from the outer peripheral surface of the end portion of the high-strength steel pipe to at least the weld metal toward the reinforcing ring is tapered on the end portion side of the high-strength steel pipe. Welded joint for high strength steel pipe. A method for producing a welded joint for high-strength steel pipes according to claim 1,
On the inner peripheral surface of the end portion of the high-strength steel pipe, a reinforcing ring having a strength lower than that of the high-strength steel pipe is used so that one end face thereof is substantially flush with the end face of the high-strength steel pipe. Welding with a weaker weld metal,
Next, the end portion of the high-strength steel pipe is cut off so that the end side of the high-strength steel pipe extends from the outer peripheral surface of the end portion of the high-strength steel pipe toward the reinforcement ring to at least the weld metal. A method for producing a welded joint for high-strength steel pipes, characterized in that the annular inclined surface is formed on the part side. A high-strength steel pipe joining method for welding one high-strength steel pipe having the weld joint for high-strength steel pipes according to claim 1 and the other high-strength steel pipe in the axial direction,
The one high-strength steel pipe and the other high-strength steel pipe are arranged so that the inclined surface of the weld joint for the high-strength steel pipe of the one high-strength steel pipe and the end surface of the other high-strength steel pipe face each other. By providing a groove portion between the inclined surface and the end surface,
Next, the high strength steel pipe joining method is characterized in that the high strength steel pipe is welded and joined by filling the groove portion with a weld metal having a strength lower than that of the high strength steel pipe. The one high-strength steel pipe and the other high-strength steel pipe, the inclined surface of the weld joint for the high-strength steel pipe of the one high-strength steel pipe and the end surface of the other high-strength steel pipe facing each other, When placing
In advance, on the inner peripheral surface of the end portion of the other high-strength steel pipe, a reinforcing ring having a lower strength than the high-strength steel pipe so that one end face thereof is substantially flush with the end face of the other high-strength steel pipe, 4. The method for joining high-strength steel pipes according to claim 3, wherein welding is performed with a weld metal having a lower strength than the other high-strength steel pipe. A high-strength steel pipe joining structure formed by welding one high-strength steel pipe having the weld joint for high-strength steel pipe according to claim 1 and the other high-strength steel pipe in the axial direction,
The one high-strength steel pipe and the other high-strength steel pipe are arranged such that the inclined surface of the weld joint for the high-strength steel pipe of the one high-strength steel pipe and the end surface of the other high-strength steel pipe face each other. By arranging, a groove portion is provided between the inclined surface and the end surface,
A joining structure of high strength steel pipes characterized in that the high strength steel pipes are welded and joined by filling the groove portion with a weld metal having a strength lower than that of the high strength steel pipes. On the inner peripheral surface of the end of the other high-strength steel pipe, a reinforcing ring having a lower strength than the high-strength steel pipe, so that one end face thereof is substantially flush with the end face of the other high-strength steel pipe, Welded by a weld metal having a lower strength than the other high-strength steel pipe,
6. The high strength according to claim 5, wherein the reinforcing ring welded to the one high strength steel pipe and the reinforcing ring welded to the other high strength steel pipe are in contact with each other. Steel pipe joint structure.

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