JPS6076292A - Production of clad steel pipe - Google Patents

Abstract

PURPOSE:To reduce the process for producing a multiple clad steel pipe by maintaining the clearance between plural base pipes of a blank material for a fitted pipe in which a powdery and granular metal is packed and subjecting the base pipes to diffusion welding thereby bonding metallurgically the entire boundary surface. CONSTITUTION:An inside stainless steel pipe 2 which is open at both ends is pressed to the bottom 6 of an outside carbon steel pipe 1 which is bottomed and closed at one end and is open at the other end and both pipes are oppositely superposed and fitted to each other via a set annular clearance. Small-sized micro balls 9 of Ni are then poured through the open end side 8 into the clearance 7 between the inside and outside pipes 2 and 1 and are packed therein to form a blank material 18 of a fitted pipe. The blank material is then put into an electron beam welding device 11 and the contact parts between the inside pipe 1 and the outside pipe 1 is seal-welded 3. The seal ring 12 having the same diameter as the outside diameter of the pipe 1 is pressed to the aerture 8 side and the inside and outside pipes 2, 1 are seal-welded 3 by a gun 13 in a vacuum state. The assembly is then subjected to diffusion joining under the temp. H and pressure P in a gaseous argon atmosphere to make metallurgical joining 16, 17 over the entire surface of the clearance 7. Two base pipes 1, 2 are thus integrally and metallurgically bound.

Description

[Detailed Description of the Invention] Technical Classification/Field> The disclosed technology applies to the technical field of manufacturing corrosion-resistant double pipes such as oil country tubular goods from block-shaped fitting materials by extrusion or the like.

<Explanation of the gist> Therefore, the claimed invention is a thick and short 13iz steel,
Mechanically fit multiple base tube materials of different types such as stainless steel,
An invention relating to a manufacturing method in which a mating tube body is formed by metallurgically bonding these mating clearances, and is then extruded in the axial direction and extended by drawing or the like to obtain a double-walled clad steel tube with a predetermined wall thickness. In particular, after filling the space between the base pipe materials that make up the above-mentioned fitting pipe material, the fitting pipe material is vacuumed and the entire clearance on the open end side is sealed and welded around the entire circumference. Maintain a vacuum state and diffuse into the joint material? The invention relates to a method for manufacturing a double clad steel pipe, in which the above-mentioned extension forming is performed after the 8-contact treatment is performed to consolidate and diffusely engage powdery metals to provide metallurgical bonding to all interfaces. It is.

<Prior Art> As is well known, oil pipes, plant piping, etc. are required to have not only pressure resistance and heat resistance against working fluids, but also corrosion resistance, wear resistance, etc.

To deal with this, for example, a corrosion-resistant double tube consisting of a stainless steel inner tube and a carbon steel outer tube is used, but even in nuclide corrosion-resistant double tubes, the inner tube may undergo buckling fracture during operation. It is desirable that the inner and outer tubes be firmly connected to prevent them from slipping.

By the way, regarding the connection of the inner and outer tubes, metallurgical connection is known, for example, rather than multilayer tubes using 4A mechanical fitting such as shrink fit.

Therefore, as a clad steel pipe manufacturing technology to deal with this problem, for example, in the building shown in Fig. 1, a carbon steel outer pipe 1 and a stainless steel inner pipe 2 are layered relative to each other, and hydraulic pipe expansion, etc. They are tightly fitted by an appropriate means, and the boundary surface is sealed by TIG welding or the like to the rear tube end all around to be fixed and integrated in the axial direction.Then, as shown in Fig. 2, the prescribed high temperature heating is completed. It is then extruded through a die 4 and a mandrel 5, or rolled out by drawing, and in the process, the inner and outer tubes 1 are
．． Two metallurgical bonds were formed on all interfaces to obtain a clad steel double pipe.

<Problems with the prior art> However, with this type of means, high temperature heating is required in addition to sufficient surface pressure when metallurgically joining dissimilar metals of the inner and outer tubes in the rolling process. A temperature much higher than the extension temperature of the one-piece pipe is required.

For example, metallurgical joining of a carbon steel outer tube and a stainless steel inner tube requires a temperature of approximately 1,200°C, which requires maintenance and inspection of the heat generating device and machinery, as well as maintenance of heat resistance, and the equipment itself has a high temperature.
li, resulting in a disadvantage of high cost.

In addition, there is a problem in that the difference in ductility and deformation resistance at high temperatures during rolling between dissimilar metals can cause tension and breakage.

Furthermore, for this reason, there was a problem in that there was a large limit to the combination of material %J of the double pipe.

In comparison, the bonding efficiency was poor (and the product yield was low).

In addition, when operating conditions are severe, triple and quadruple pipes may be designed to be flooded in order to prevent hydrogen cracking and to deal with internal and external corrosive fluids, but these pitcher pipes cannot be rolled. There were also drawbacks.

<Purpose of the Invention> The purpose of the invention of this application is to solve the above-mentioned problems of manufacturing double clad steel pipes related to the prior art, and to solve the problems in the manufacturing of double clad steel pipes. degree is obtained,
The metallurgical bonding of the joint surfaces is ensured, which shortens the process of manufacturing double pipes, and streamlines the design and processing.Furthermore, the thickness of each base pipe material can be freely selected, making it suitable for various key industries. The purpose of this invention is to provide an excellent method for manufacturing clad steel pipes that is useful in the field of piping applications.

<Structure of the Invention> In accordance with the above-mentioned purpose, the structure of the invention of this application, whose gist covers the scope of the above-mentioned claims, consists of a plurality of different materials having a predetermined thickness and length, in order to solve the above-mentioned problems, Each base tube material is layered relative to each other, and the space between them is filled with powder and granular metal, and the thus obtained fitted tube body is brought into a vacuum state including the clearance between the base tube materials, and in that state. , maintain the vacuum degree of the clearance by seal welding the end clearances on the open end sides of the plurality of base pipe materials, and then perform well-known diffusion welding to fit the powder metal through consolidation diffusion bonding. Metallurgical bonding of the entire clearance of the joint tube body is obtained, and after that, or during that time, the other base tube materials of the base tube material that has been consolidated and diffusion bonded are removed, and then extruded and pulled out through a die, mandrel, etc. This technical means is such that a composite clad steel pipe of a predetermined length is obtained by axially elongating the fitting pipe material.

<Embodiment> Next, one embodiment of the invention of this application will be described below with reference to the drawings from FIG. 3 onwards.

Note that the same parts as in FIG. 1.2 will be described using the same reference numerals.

In the embodiment shown in FIGS. 3 to 8, first, as shown in FIG. The metal powder of a predetermined minute size is brought into contact with the bottom 6 and interposed in a relative overlapping manner through a set ring-shaped clearance, and then, as shown in FIG. The fitting tube body 10 is increased by +5 by pouring in the microhole iff 9 of N1 and filling it completely.

Next, the fitting tube cable body 10 is set in a well-known electron beam welding device 11 as shown in FIG. A seal ring 12 having the same diameter as the outer periphery of the outer tube 1 is brought into contact with the opening 8, and in a vacuum state, seal welding 3 is performed on the entire circumference of the outer tube 1 and the inner tube 2 using a gun 13, and each of the two base tube materials is 1. Perform sealing around the entire circumference of the joint end clearance 7 in step 2.

Therefore, in this embodiment, prior to the seal welding 3 in the electron beam welding device 11, each base tube material 1.
2 is closed by the bottom surface 6 of the outer envelope 1 at one end, and by the seal welding 3 on the open end 8 side, each base tube material 1.
For the total clearance 7 of 2, after seal welding 3.3,
The vacuum state will be completely maintained.

Immediately or after a predetermined period of time after performing the seal welding 3, the sealed fitting tube body 10 is set in a well-known diffusion welding device 14 as shown in FIG. When diffusion welding is performed in an atmosphere at a predetermined temperature 1-1 and a pressure P for a predetermined time, the Ni microball group 9 becomes a consolidation diffusion-bonded metal 15 through the metal atomic transfer to each base tube material 1. The metallurgical joints 1G and 17 are formed over the entire surface of the clearance 7 while maintaining the above degree of vacuum between the two base pipes 1.2, thereby completing the integral metallurgical connection of the two base pipes 1.2.

During this time, the fine gaps between the Ni microball groups 9 filled in the initial clearance 7 are sufficiently absorbed by the change in thermal behavior of the inner and outer tubes 2.1.

Therefore, the metallurgically bonded tube body 18 is taken out from the diffusion welding device 14, and the closed end side of the bottom surface 6 and the seal disk 12 are cut and removed as shown in FIG. Die 4, mandrel 5 of the well-known drawing device
By setting the pipe and drawing it to a predetermined value, a triple clad steel pipe 19 with a predetermined thin wall thickness is obtained.

In this process, the tube body 18 is pulled and damaged because the two base tubes 1.2 are strongly bonded metallurgically by the diffusion atoms of the N1 consolidation diffusion bonded metal as described above. There is no risk of this occurring.

Moreover, of course, the metallurgical bond will not be broken by cutting and removing the bottom surface 6 and the closed end side of the seal disk 12.

After the long triple-clad steel pipe 19 has been cut, it is sufficient to cut and separate it into each predetermined unit pipe, and each of the cut unit pipes is metallurgically processed by connecting the base pipe material 1.2 to the N1 bonding metal. They are combined and can fully achieve their original functions.

Of course, it is also possible to use it in the form of a long tube.

In the embodiment shown in FIGS. 9 to 14, a columnar stainless steel core material 2' is inserted and layered as a core metal through a predetermined clearance 7 into a carbon steel outer tube 1 with both ends open. As shown, a seal disk 12 is brought into contact with one open end and fixed integrally around the periphery via a seal weld 3 so that the predetermined clearance 7 between the two can be formed into a ring shape with a uniform cross section. Then, the clearance 7 between the base tube materials 1 and 2' is filled with a group of microballs 9 made of the same powdery metal as in the above embodiment, also made of, for example, Ni, and as shown in FIG. As shown, the microballs are set in the same electron beam welding device 11 as described above, and a sealing disk 12 is brought into contact with the other open portion, and sealing welding 3 is performed using a gun 13 to remove Ni from the microball group. The filled clearance 7 is evacuated and seal welding 3 is performed, and then, as shown in FIG. 12, diffusion welding is performed in the same manner as described above to consolidate and diffuse bond the micro balls 9 to the fitting tube material 18. The base tube materials 1 and 2' are diffusion bonded and integrated via
The seal disks 12 and 12 are appropriately cut and removed from both ends of the core bar 2', and the column body 21 is cut and removed using an appropriate cutting device on the base tube material 2' of the core material as a core metal, and the column body 21 is removed by cutting off the base pipe material 2' of the core material as a core bar. In this embodiment, an inner pipe 22 of a set thickness is formed inside the metal 15, and a clad steel pipe 19 is formed using a die 4 and a mandrel 5 in the same manner as in the embodiment described above, as shown in FIG. In this case, the core metal 2' forms the middle tube of the consolidation-diffusion bonded metal 15 during diffusion welding, and also participates in the formation of the inner tube in the subsequent work.

In addition, in the embodiment J3 not shown in FIGS. 15 to 20, a ceramic tube 2' as a columnar base tube material is inserted as a core bar through a predetermined clearance 7 into a carbon steel outer tube 1 with both ends open. A seal disk 12 is placed at one open end so that the predetermined clearance 7 between the two can be formed in a ring shape with a uniform cross section as shown in FIG.
are brought into contact and integrally fixed around the periphery via seal welding 3,
The clearance 7 between the base tube material 1 and the ceramics 2' is filled with the same powdery metal as in the above-mentioned embodiment, for example, micro-ball groups 9 of Ni, and as shown in FIG. Similarly, a sealing disk 1 is set in a similar electron beam welding device 11 and placed in another open part.
2 and perform seal welding 3 with gun 13,
Clearance filled with N1 of the microball group
7 is evacuated and seal welding 3 is performed, and then, as shown in FIG.
The base tube materials 1 and 2' are diffusion bonded and integrated by compressing and diffusion bonding the micro balls 9 to the tube body 18', and as shown in FIG. The seal disk 12.12 is appropriately cut and removed, and the ceramic core material 2' as a core metal is appropriately removed using a suitable cutting device, and the above-mentioned consolidation diffusion bonded metal 1 is removed.
In this embodiment, an outer pipe 1 of a set thickness is integrally formed on the outside of the steel pipe 5, and as shown in FIG. In this case, the ceramic core metal 2' participates in the formation of the consolidation diffusion bonded metal 15 during diffusion welding.

As an equivalent embodiment of this embodiment, it is also possible to fill the space between the ceramic outer tube and the metal inner tube with granular metal to form a consolidation diffusion bonded metal, and then remove the welded ceramic outer tube.

It goes without saying that the embodiments of the invention of this application are not limited to the above-mentioned embodiments; for example, in addition to triple pipes, quadruple pipes can also be manufactured, and TJG welding can also be used for end seal welding. Various aspects can be adopted, such as extrusion molding is also possible for the axial extension process.

The core material inserted into each base tube can be made of various metals, and the powder metal may be Ni-based alloy or 5US4.
Of course, it is possible to adopt various types, such as 20, etc., as well.

<Effects of the Invention> According to the invention of this application, basically, when the boundary joint surfaces of double pipes such as ordinary corrosion-resistant pipes are clad-joined over the entire surface, it is almost impossible to directly connect the entire length. By using diffusion welding to manufacture short, thick-walled clad pipes in advance, it is possible to metallurgically join multiple boundary joint surfaces at once, and it has the excellent effect of being able to achieve the same accuracy over the entire surface without internal defects. be done.

By filling the relative overlapping clearance of multiple base pipe materials with powdered metal such as Ni and performing consolidation diffusion diffusion bonding, it is not necessary to insert other base pipe materials during the base pipe period. It is effective and requires less man-hours.

Further, it is possible to join the entire surface regardless of the length, thickness, and clearance between the short base tube materials, and there is also the effect that a plurality of base tube material fitting material tubes can be simultaneously diffusion welded.

Furthermore, by performing diffusion welding in advance in this way, the powder metal filled in the base tube material clearance is completely consolidated and diffusion bonded, and the metal atoms diffuse into the base tube materials, making the mating tube material metallurgical. Since it is connected, it has the effect of increasing the degree of freedom in shape and reducing the number of man-hours, and in addition, it can be used as is with extrusion molding equipment like ordinary carbon steel pipes.
It does not cause product defects such as warping or breakage during stretch forming, and it also has the advantage that it can be done at low humidity, unlike cladding by rolling welding or the like.

In addition, unlike rolling, it has the effect of providing a greater degree of freedom in selecting the material for the base tube material.

Furthermore, it is flexible enough to be able to manufacture not only double pipes but also double pipes, quadruple pipes, and other double pipes.

In addition, by using a base tube material such as ceramics as a core material or an outer tube, granular metal is interposed between it and another casing, and the bonded metal is bonded by consolidation and diffusion bonding, and the base tube material such as ceramics is removed. It can also be used as a lined pipe body, and has the effect that a base pipe material such as ceramics can be used repeatedly as a medium.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a fitting tube of a double pipe based on the prior art, FIG. Figures 1 to 8 are process explanatory diagrams of one embodiment, Figure 3 is a cutaway perspective view of the base tube material, Figure 4 is a cross-sectional view of the fitting tube material, and Figure 5 is the fitted tube material. 6 is a cross-sectional view illustrating diffusion welding, FIG. 7 is a sectional view illustrating cutting and removal of the end of a joint pipe, FIG. 8 is a sectional view illustrating tube extension forming, and Figures 9 to 14 15 to 2 are process explanatory flow diagrams corresponding to FIGS. 3 to 8 of other embodiments.
FIG. 0 is a process explanatory flowchart of an embodiment corresponding to FIGS. 9 to 14. 1.2.2'...Base pipe material 12.13...Boundary surface,
10.10'...Mating pipe material, 9...Powder metal, 7...Clearance, 8...Open end (frontage), 3...Seal welding, 14...Diffusion Welding (equipment), 17... Clad steel pipe, applicant Kuroki Kogyosho Co., Ltd.

Claims (2)

[Claims] (1) After fitting a plurality of base pipe materials and metallurgically joining the quay interfaces between the base pipe materials, the fitted pipe body is extended and deformed in the axial direction to obtain a double clad steel pipe of a predetermined length. In the manufacturing method, after the base tube material is filled with powdered metal, the clearance between the multiple base tubes of the fitting tube cable body is brought into a vacuum state, and the open end of the mutual clearance between the base tube materials is sealed all around. After welding and maintaining a vacuum state in each clearance, the fitting tube body is diffusion welded, and then the axial extension deformation is performed to obtain a double clad steel tube of a predetermined length. How to manufacture clad steel pipes? Leave. (2) A plurality of five pipe materials are fitted together and the interface surfaces between their base pipes I are metallurgically bonded, and the 11 lid joint pipe is extended and deformed in the direction of the main pipe body to obtain a double clad steel pipe of a predetermined length. In the manufacturing method described above, after the base tube material is filled with granular metal, the clearance between the plurality of base tubes of the mating tube element body is brought into a vacuum state, and the open end of the mutual clearance between the base tube materials is expanded around the entire circumference. After seal welding to maintain a vacuum state in each clearance, the mating tube body is diffusion welded, and the other base tube materials of the consolidated and diffusion bonded base tube material of the powder metal are removed and the sliding door is sealed. A method for manufacturing a clad m-whistle, characterized in that a double clad steel pipe of a predetermined length is obtained by performing the axial extension deformation.