JP3694752B2 - Compound pipe manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a container of liquid having a corrosion resistance, a method of manufacturing a composite tube suitable for use as a pipe material or the like.
[0002]
[Prior art]
Containers and piping for fuel cells and the like are required to have a material with high corrosion resistance. Also, petrochemical, general industrial chemistry, nuclear power industry, etc. require piping materials and container materials that are excellent in corrosion resistance, but as a material that can withstand these corrosive atmospheres and corrosive solutions, different materials have been used in the past. A clad material obtained by pressure bonding, a metal surface sprayed with a metal, an inorganic material or the like, and a metal surface subjected to electrostatic coating or plating.
[0003]
However, the above-described pressure-bonding clad material has a problem that the tensile strength of the material to be pressure-bonded must be within a certain range, so that the material is limited. On the other hand, when spraying or coating the inner surface of a metal tube, there is a problem that the inner diameter and length of the tube are limited. Further, as plating methods for improving the corrosion resistance, there are hard chrome plating, nickel plating and the like, but there is a problem that none of them can sufficiently cope with the use conditions. Furthermore, some of the above conventional methods are not suitable for recycling metal pipes.
[0004]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to improve the problems of the conventional materials and to provide a pipe material having excellent performance such as corrosion resistance.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs the following configuration. That is, in the method for manufacturing a composite tube according to the present invention, a metal core having a diameter smaller than that of the metal tube is inserted into the metal tube, and a metal powder or other inorganic powder is interposed between the metal core and the inner surface of the metal tube. In addition, one or more of the synthetic resin powders are filled, and the gap between the inner surface of the metal tube and the cored bar is closed at the front end and the rear end of a predetermined processing range, so that the internal powder flows out. Insert a bushing to prevent the metal tube from being pulled out of the metal tube through a drawing die having a smaller diameter than the outer diameter of the metal tube, and then pull out the metal bar from the metal tube to dissimilar the inner surface of the metal tube. It is characterized by obtaining a composite tube in which a different kind of coating layer is formed of one kind or plural kinds of particles of metal powder, other inorganic powder, and synthetic resin powder .
[0006]
Hereinafter, specific examples of the present invention shown in the drawings will be described in detail.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with specific examples, but the present invention is not limited to these specific examples. The metal tube used as a raw material in the present invention has a workability that can be drawn, and examples of the material include metals and alloys such as aluminum, copper, steel, and stainless steel. . Among these, it is particularly preferable to use an aluminum tube from a practical viewpoint such as corrosion resistance and workability.
[0008]
The dissimilar coating layer is formed on the inner surface of the metal tube. The method will be specifically described with reference to the drawings as follows.
[0009]
First, a drawing process as shown in FIG. 2 is applied to the tip of the metal tube 1 that has been subjected to the oxide film removal process, and a ring-shaped first bush 2 is attached as a partitioning material to the rear inner side of the drawing process. The bush 2 is in close contact with the inner surface of the metal tube 1 and partitions so that a filling powder described later does not flow out during processing. The thickness of the bush 2 (difference between the outer diameter and the inner diameter) varies depending on the type of filling powder, the inner diameter of the metal tube, the thickness of the coating layer to be formed, and is usually several millimeters. For fixing the bush 2 to the metal tube 1, a method of adhering and fixing using an appropriate adhesive (for example, paste-like epoxy, nitrile epoxy, film-like nylon epoxy, nitrile phenolic, formal phenolic, etc.) is simple. It is also possible to employ other fixing methods such as welding. The second bush 6 is fixed to the inner surface of the metal tube 1 as shown by a chain line in FIG.
[0010]
A metal core 3 is inserted into the inside of the metal tube 1 to which the bush 2 is attached. The diameter of the metal core 3 is in a size inscribed in the bush 2 and is provided with a constricted portion including a conical inclined surface portion 3a and a straight portion 3b at the tip. The outer diameter of the main body 3c of the metal core 3 is slightly smaller (about 1.5 to 2.0 mm) than the inner diameter of the target composite tube, and the outer diameter of the straight portion 3b is that of the throttle portion of the metal tube. The same as the inner diameter of the tip.
[0011]
When the metal core 3 is inserted into the metal tube 1, the gap 5 between the metal core 1 and the inner surface of the metal tube 1 is filled with the coating powder 5. After that, a second bush 6 similar to the front end bush 2 is fitted and fixed inside the rear end. This is to prevent the filled powder 5 from flowing out. The method of fixing the bush 6 may be the same as that of the bush on the front end side.
[0012]
After inserting the cored bar 3 into the interior and filling the gap with the cored bar with the powder for forming the coating, the metal tube 1 is drawn with a thin tip (inside the tip straight part 3b of the cored bar). Is inserted into the die 10 and the metal tube is drawn through the die together with the cored bar. The diameter of the die 10 is substantially the same as the outer diameter of the target composite pipe, and the inlet portion is a trumpet-shaped inclined surface similar to the inclined surface portion of the core metal.
[0013]
When the drawing process is finished, the cored bar 3 is drawn backward to cut and remove unnecessary portions such as a drawn portion of the metal tube, and cut to a predetermined length to obtain a desired composite tube 20. In the composite tube obtained in this way, the coating layer 7 made of the filling powder 5 is integrally formed on the inner surface. The characteristics, thickness, etc. of the coating layer can be made desired by selecting the type and amount of the filling powder. Therefore, for example, in the case of a composite pipe that requires corrosion resistance, a coating layer having excellent corrosion resistance can be obtained by filling a powder having corrosion resistance.
[0014]
【Example】
A pure aluminum (JIS 1050) tube was used as the metal tube. The metal tube had an outer diameter of 70 mm and an inner diameter of 63 mm. Further, a mixed powder of stellite and pure nickel was used as the filling powder. The particle size of the powder was 20-30 microns, and the component ratio was 90% for stellite and 10% for nickel.
[0015]
The tip of this aluminum tube is subjected to a drawing process by swaging (reducing the diameter for passing a die), and a ring-shaped bush 2 made of aluminum of the same material as the aluminum tube is provided on the inner surface behind it. Fixed with adhesive. Then, a mandrel 3 made of manganese steel having the same diameter as the inner diameter of the bush was inserted into the aluminum tube from the rear end side. The shape of the cored bar is as shown in FIG. 3, and the dimensions of each part were such that the diameter of the tip straight line part 3b was 40 mm and the diameter of the main body part 3c having a large diameter was 61.2 mm. Thereafter, the space (gap) between the metal tube and the metal core was filled with the filling powder from the rear end side of the metal tube. When a sufficient amount of powder was filled, an aluminum bush 6 similar to the above was fitted into the rear end portion of the powder filling portion and fixed with an adhesive.
[0016]
Next, the tip of the aluminum tube is inserted into the drawing die together with the core metal inserted therein, the metal tube coming out of the die and the tip of the core metal are gripped by the chuck of the 10 ton extraction device, Or the drawing process was performed warm. In this drawing process, the metal tube and the powder are heated to a high temperature of several hundred degrees by frictional heat, processing heat, etc., and the powder particles adhere to the surface of the metal tube in a state of being overlapped by the processing pressure. An alloy layer was formed at the contact portion.
[0017]
By this drawing process, the aluminum tube was squeezed to reduce its diameter and length, and a composite tube having an inner diameter of 62 mm was obtained. The cored bar was pulled out from the composite tube, and unnecessary portions were end-cut, and cut to a predetermined length to obtain a desired composite tube. As described above, the filled powder is crushed and adhered to the inner surface of the composite tube with a thickness of about 70 microns. The aluminum alloy coating layer 7b ( A thickness of several microns to several tens of microns) was formed. In addition, the aluminum tube itself was work hardened, and its own corrosion resistance was improved.
[0018]
The obtained composite tube has an alloy layer and a powder particle layer formed on the inner surface of the original metal (aluminum), has excellent corrosion resistance, and can withstand long-term use as compared to A1050 (JIS) material. . The powder particle layer was considerably peeled when the cored bar was pulled out, but the corrosion resistance was maintained because the alloy layer was present on the inner surface layer of the metal tube even when the particles were peeled off.
[0019]
【The invention's effect】
As is apparent from the above description, according to the present invention, a composite pipe made of a metal pipe having an inner surface formed with a different type coating layer such as a corrosion-resistant coating layer can be manufactured relatively easily. Further, according to the production method of the present invention, it is possible to easily produce a long and small caliber that cannot be sprayed or electrostatically coated.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a manufacturing method example of the present invention.
FIG. 2 is an explanatory diagram of a metal tube.
FIG. 3 is an explanatory diagram of a cored bar.
FIG. 4 is an explanatory diagram immediately before the drawing process.
FIG. 5 is an explanatory view during a drawing process.
FIG. 6 is a cross-sectional view showing the structure of the obtained composite pipe.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal pipe 2 Bush 3 Core metal 5 Powder 7 Coating layer 10 Dice 20 Composite pipe

Claims (1)

A metal core having a diameter smaller than that of the metal tube is inserted into the metal tube, and one or more of metal powder, other inorganic powder, and synthetic resin powder are inserted between the metal core and the inner surface of the metal tube. In addition, a bush that closes the gap between the inner surface of the metal tube and the cored bar to prevent the powder from flowing out is fixed at the front end and the rear end of a predetermined processing range. After drawing the metal tube together with the core through a drawing die having a smaller diameter than the outer diameter, the core is pulled out of the metal tube, so that different metal powders, other inorganic powders and synthetic resin powders are formed on the inner surface of the metal tube. A method for producing a composite tube, comprising obtaining a composite tube having a different kind of coating layer formed of one or more kinds of particles.

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