JPH07214153A - Production of high-strength corrosion resistant branch pipe - Google Patents

Abstract

PURPOSE:To provide a means capable of solving all of problems associated with a hot ball method and problems associated with a chipping out method to be adopted when a branch pipe having a desired shape is desired to be obtd. at the time of producing a high-strength corrosion resistant branch pipe by integrating an outside layer part consisting of a high-strength material and an inside layer part consisting of a corrosion resistant material. CONSTITUTION:The outside layer part 1 is formed to a branch pipe shape independently from the inside layer part 2 and thereafter, a cylindrical body 5 for forming the inside layer part 2 is fitted to a part corresponding to a straight pipe part 4 of this outside layer part 1. The opening end of a part corresponding to a branch part 3 is maintained in a deaerated, sealed and capped state by a cap 6 and thereafter, such assembly is subjected to a hot isostatic compression treatment to integrate both layer parts 1, 2 while the cylindrical body 5 is tightly adhered and deformed to the respective inside surface of the outside layer part 1 and the cap 6. The cap 6 and the opening end of the branch part 3 are then removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high-strength corrosion-resistant branch pipe used for petroleum pipes, etc., and more specifically, it intersects with a straight pipe portion at an intermediate portion in the longitudinal direction of the straight pipe portion. When manufacturing a branch pipe in which a branch portion that branches in a direction is connected, the outer layer portion of the branch pipe is made of a high-strength material, and the inner layer portion is made of a corrosion-resistant material, and both of these layer portions are formed. The present invention relates to a method for manufacturing a high-strength corrosion-resistant branch pipe by integrating them.

[0002]

2. Description of the Related Art High-strength corrosion-resistant branch pipes used for applications such as branch joints in petroleum pipes from subsea oil fields to offshore bases are structural carbon steel, stainless steel, or high-strength materials such as cast steel. Inconel6 with the outer layer composed of
An inner layer portion made of a corrosion-resistant material such as 25 or Incoloy 825 is integrated into a branch pipe shape. In order to manufacture such a high-strength corrosion-resistant branch pipe, conventionally, a two-layer pipe (for example, a two-layer pipe) in which an outer layer portion made of the high-strength material and an inner layer portion made of the corrosion-resistant material are integrally molded in a straight pipe state (A straight tube that has been centrifugally cast into a state), an opening is provided by machining in the portion where the branch is to be formed, and then the two-layer tube is heated to an appropriate hot working temperature while the two-layer tube is formed. By subjecting the pipe to a process in which a semi-spherical jig with a rod is moved from the inside of the pipe to the outside of the pipe through the opening so as to squeeze the opening of the pipe (hereinafter, referred to as hot-ball-punching method), The method of forming a branch part and completing the said branch pipe was implemented.

[0003]

However, according to the above-mentioned conventional method, since the double-layer pipe is processed so that the opening portion of the pipe is locally squeezed, the double-layer pipe is made of the corrosion-resistant material. A problem that wrinkles occur such that the inner layer part bulges outward at the opening part, and the shape of the finally obtained branch pipe (particularly, the cross-sectional shape of the branch part) cannot be made into a desired shape. was there. Therefore, in order to obtain the branch pipe having a desired shape, a method of shaving a material entirely made of the corrosion resistant material into a branch pipe shape by machining (hereinafter referred to as a shaving method) has been conventionally used. However, in the case of this shaving method, the processing cost becomes very high, and it becomes necessary to adopt a thick branch pipe in order to obtain a predetermined strength, and it is difficult to realize a thin and lightweight product. There was a problem. The present invention has been made by paying attention to such an actual situation, and there are problems in the conventional hot ball punching method and problems in the carving method adopted when a branch pipe having a desired shape is desired. , All of them are intended to provide means that can be solved at once.

[0004]

The characteristic construction of the method for producing a high-strength corrosion-resistant branch pipe according to the present invention (hereinafter referred to as the method of the present invention) is that the straight pipe portion intersects with the straight pipe portion at the longitudinal middle portion. When manufacturing a branch pipe in which a branch portion that branches in the direction of is formed, the outer layer portion of the branch pipe is made of a high-strength material, and the inner layer portion is made of a corrosion-resistant material, and both of these layer portions are formed. A method of manufacturing a high-strength corrosion-resistant branch pipe by integrating the outer layer portion, after being formed into a branch pipe shape independently of the inner layer portion, in the outer pipe portion corresponding to the straight pipe portion. A tubular body for forming the inner layer portion is fitted inside, and an opening end of the portion corresponding to the branch portion in the outer layer portion is covered with a lid to evacuate the inner space of the portion corresponding to the branch portion and seal the inner space. While maintaining the covered state, the combination of them is subjected to hot isostatic pressing. The point of removing the opening ends of the lid body and the branch portion after the tubular body is brought into close contact with the inner surface of the outer layer portion and the inner surface of the lid body while the both layer portions are integrated. It is in.

[0005]

According to the method of the present invention as described above, the tubular body for forming the inner layer portion is fitted in the portion corresponding to the straight pipe portion in the outer layer portion formed independently of the inner layer portion into the branch pipe shape, Moreover, since the hot isostatic pressing process is performed while the open end of the portion corresponding to the branching portion of the outer layer portion is covered with the inner space in a sealed state, the tubular body is conventionally used. The local ironing process like the hot ball punching method is not applied, but the isotropic pressing process to each inner surface of the outer layer part and the lid is based on the hot isostatic pressing process. Will be granted. Therefore, the cylindrical body can be effectively deformed in close contact with each inner surface of the outer layer portion and the lid body.
In addition, the both layer portions are effectively integrated. As a result, a problem that occurs in the case of using the conventional hot ball punching method, that is, wrinkles that the inner layer part partially bulges outward, and a high-strength corrosion-resistant branch pipe having a desired shape cannot be obtained. That problem will be solved. In addition, as described above, after the tubular body is effectively and closely deformed on the inner surfaces of the outer layer portion and the lid body, and after the both layer portions are effectively integrated, the lid body and the By removing the open end of the branch portion, the final shape of the high-strength corrosion-resistant branch pipe can be easily manufactured. Further, by the hot isostatic pressing process described above, a substantially finished product of a high-strength corrosion-resistant branch pipe in which the outer layer portion and the tubular body fitted therein are collectively integrated, and the both layer portions are effectively integrated. As a result, it is possible to reduce the processing cost as compared with the carving method in which a material made entirely of a corrosion-resistant material is carved, and the presence of the outer layer part made of a high-strength material makes the product thinner and lighter. Will be realized.

[0006]

As described above, according to the method of the present invention, there are problems in the conventional hot ball punching method and the problems in the shaving method adopted when a branch pipe having a desired shape is desired.
All of them are resolved all at once, and the object of the present invention is achieved.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the procedure of one embodiment of the method of the present invention.

In the figure, 1 is a structural carbon steel (for example, JI
S standard: S45C or various standard steels close thereto or stainless steel (for example, JIS standard: SUS304, S)
US316 or various standard steel materials close to them, or an outer layer portion composed of a high-strength material such as cast steel, and 2 is an appropriate corrosion resistant material (for example, Inconel625
Or an anticorrosion alloy such as Incoloy 825).

To explain the procedure of the method of the present invention, first, the outer layer portion 1 is replaced with the inner layer portion 2 (see FIGS. 1 (d) and 1 (e)).
Independently of, is formed into a branch pipe shape (wall thickness: 23 mm) (see FIG. 1 (a)). The shaping into the branch pipe shape is completed, for example, as follows. That is, a centrifugal casting pipe made of the high-strength material is adopted as a raw pipe, and an opening is formed in the portion where the branch portion 3 is to be formed by machining, and then the raw pipe is appropriately cut. While heating to the hot working temperature, a process of moving a semi-spherical jig with a rod from the inside of the pipe to the outside of the pipe so as to squeeze the opening of the pipe (that is, the above-mentioned By performing a hot ball punching method, the branch portion 3 is formed and the molding into the branch pipe shape is completed. In addition, molding into this branch pipe shape is
It is also possible to use other means other than the above-mentioned method (for example, bulge molding or casting method).

After the outer layer portion 1 is independently formed into a branched pipe shape in this manner, the inner layer portion 2 (see FIG. )reference)
The tubular body 5 (thickness: 3 mm) for forming is fitted inside (Fig. 1).
(See (b)). The tubular body 5 can be easily obtained by winding a plate-shaped material made of the corrosion-resistant material into a cylindrical shape, and then TIG-welding the butted portion to complete the cylindrical body. Can also be easily obtained by the centrifugal casting method.

Then, the open end of the outer layer portion 1 corresponding to the branch portion 3 is made of a material having good weldability (for example, J
With the lid body 6 (wall thickness: 40 mm) made of IS standard: S25C or various standard steel materials close thereto, the interior space of the portion corresponding to the branch portion 3 is degassed and sealed to maintain the lid state ( (See FIG. 1C). Specifically, maintaining the lid in the sealed state is performed as follows. That is,
All of the joint exposed portion 7 between the outer layer portion 1 and the tubular body 5 and the joint exposed portion 8 between the outer layer portion 1 and the lid 6 can be sealed by TIG welding or electron beam welding. The welded portion 7 or 8 is to be welded in a state where at least the welded portion 7 or 8 is welded at the end for degassing of the internal space.
Are welded by the electron beam welding method. It should be noted that all exposed seams 7, 8 may be electron beam welded.

Then, the combination of the outer layer portion 1, the tubular body 5 and the lid 6 is loaded into the hot isostatic pressing apparatus, and the combination is subjected to appropriate conditions (for example, temperature). :
The tubular body 5 is subjected to a hot isostatic pressing treatment at 1100 to 1200 ° C. and a pressure of about 1000 atm.
The outer layer portion 1 and the inner layer portion 2 are integrated while being closely deformed on the inner surfaces of the outer layer portion 1 and the lid 6 (FIG. 1).
(See (d)).

After that, the lid 6 and the opening end of the branch portion 3 are removed by a cutting process at a low processing cost (see FIG. 1 (e)) to obtain a desired high-strength corrosion-resistant branch pipe. .

Next, another embodiment will be described. In the above-described embodiment, in order to maintain the state in which the inner space of the branching portion corresponding to the branching portion is degassed and sealed and the lid is maintained, in addition to the TIG welding method, electron beam welding is performed in a vacuum atmosphere. We decided to use the welding method, but if you do not want to use the electron beam welding method for various reasons, after welding all exposed seams by the TIG welding method, for example, attach it to the lid body while inserting it. It is also possible to adopt a means of vacuum degassing the internal space via the degassing tube and then pinching the degassing tube.

In the above-mentioned embodiment, the method of the present invention is applied to the method of manufacturing a branch pipe having one branch portion, but the method of the present invention is also applied to the method of manufacturing a branch pipe having a plurality of branch portions. Can be applied.

Needless to say, the material of the outer layer portion and the material of the inner layer portion are not limited to those of the above-mentioned embodiment.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the procedure of the method of the present invention.

[Explanation of reference numerals] 1 outer layer portion 2 inner layer portion 3 branch portion 4 straight pipe portion 5 tubular body 6 lid

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B32B 15/01 C // F16L 41/02 (72) Inventor Hiroshi Makino Naniwa-ku, Osaka City, Osaka Prefecture 2-47 Tsutou Kubota Co., Ltd. (72) Inventor Hiroaki Okano 1-247 Shishitsuhigashi, Naniwa-ku, Osaka City, Osaka Kubota Co., Ltd.

Claims (1)

[Claims] 1. When manufacturing a branch pipe in which a branch portion (3) for branching in a direction intersecting with the straight pipe portion (4) is continuously provided at an intermediate portion in the longitudinal direction of the straight pipe portion (4), the branch is produced. The outer layer portion (1) of the pipe is made of a high-strength material, and the inner layer portion (2) is made of a corrosion resistant material, and both of these layer portions (1), (2)
A method for manufacturing a high-strength corrosion-resistant branch pipe by integrating the outer layer portion (1) and the outer layer portion (1) after forming the outer layer portion (1) into a branch pipe shape independently of the inner layer portion (2). ), The tubular body (5) for forming the inner layer portion (2) is fitted in the portion corresponding to the straight pipe portion (4), and the portion corresponding to the branch portion (3) in the outer layer portion (1). The open end of the lid body (6) is degassed and sealed in the interior space of the portion corresponding to the branching portion (3) to maintain the lid-covered state, and then the combined body is subjected to hot static treatment. The tubular body (5) is subjected to a hydraulic compression treatment.
After the two layer portions (1) and (2) are integrated while deforming the inner layer of the outer layer portion (1) and the inner surfaces of the lid body (6) in close contact with each other, the lid body (6) and the branch. A method for manufacturing a high-strength corrosion-resistant branch pipe, wherein an open end of a portion (3) is removed.