JPS5969480A - Ceramic doubletube and manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The disclosed technology is in the field of corrosion-resistant double-pipe construction and manufacturing technology.

Therefore, the invention of this first song is an invention relating to a corrosion-resistant and pressure-resistant double pipe in which the outer W is a metal pipe made of carbon steel and the inner pipe is made of ceramic, and both pipes are firmly connected, and a method for manufacturing the same. In particular, highly active titanium foil is added to the outside of the ceramic inner tube, and a brazing material is interposed between the titanium and the metal outer tube, and titanium is diffused into the ceramic by high-temperature, high-pressure diffusion welding. However, the present invention relates to a ceramic double tube in which titanium is bonded to a metal outer tube through brazing, and a method for manufacturing the same.

As is well known, piping is used to process and transport corrosive fluids in many industries such as the petroleum industry and the nuclear industry, and piping is designed to have not only pressure and heat resistance but also corrosion and wear resistance during this process. However, there are cases where it is not technically possible to meet this requirement with one material, or the cost does not match, so the pressure and heat resistance is lower than that of the outer tube. A double pipe is used, with the inner pipe providing corrosion and wear resistance.

Up until now, the outer tube has generally been made of carbon steel, etc., and the inner tube has been made of stainless steel, etc., in other words, both the inner and outer tubes have been made of metal, but with advances in material science, Products with better corrosion resistance, lighter weight, lower coefficient of thermal expansion, and less thermal behavior are being developed and put into practical use, and among them, ceramics are attracting attention. It's coming.

In this case, for example, as shown in Fig. 1, a ceramic inner tube 2 is fitted onto a carbon steel outer tube 1, and the double tube 3 is bonded by means such as shrink fitting. There were disadvantages in that the bonding strength was not sufficient, causing axis misalignment, and cracking due to uneven pressure distribution.

Alternatively, there are methods such as thermal spraying, but there is a problem that the mechanical strength is not determined by light, and if metallurgical bonding is performed by brazing, it is difficult to ensure that the solder does not damage the ceramic. Ta.

The purpose of the invention of this application is to solve the problems of the above-mentioned conventional ceramic inner tube-coupled two-east tube, to make it possible to metallurgically bond the ceramic inner tube to the metal outer tube, and to solve the two problems. In addition to the original function of the double pipe, it is possible to take advantage of the advantages of ceramics, and it is possible to form a highly reliable double pipe, which can be beneficial in the field of piping application in various industries. The present invention aims to provide a ceramic double tube and a method for manufacturing the same.

In order to solve the above-mentioned problems, the invention of this application, which is based on the above-mentioned claims in accordance with the above-mentioned object, is designed to solve the above-mentioned problems by connecting the ceramic inner tube to the ceramic side between the inner tube and the outer tube made of carbon steel or the like. Foil or powdered titanium is used as a material tube by interposing a brazing material such as silver on the outer tube side, and the material tube is placed in a diffusion bath welding device seven times and subjected to high temperature and high pressure. The titanium diffuses into the ceramic and the brazing material, and the brazing material joins the titanium foil and the metal outer tube, thereby metallurgically bonding the ceramic inner tube and the metal outer tube to ensure strength. The material applies compressive residual stress to the ceramic inner tube after cooling because it melts and fills the space between the metal outer tube and the ceramic tube, and functions to prevent cracking during operation. Technical measures have been taken to fully utilize the performance of low thermal behavior due to the small coefficient of expansion S.

Next, embodiments of the invention of this application will be described below with reference to the drawings from FIG. 2 onwards. Note that the same reference numerals will be used to describe the same parts as those shown in FIG.

First, as shown in FIG. 2, a tubular silver solder 4 having a predetermined diameter is expanded by heating and then fitted into a titanium foil 5, which is also tubular and has a predetermined diameter, in a relatively overlapping manner and kept at room temperature.

On the other hand, a carbon steel outer tube 1 whose diameter has been enlarged at high temperature and a ceramic inner tube 2 whose diameter has been reduced by cooling are layered relative to each other to form a material tube 3'.

The material tube 3' is then mechanically lowered when it is brought to room temperature.

Therefore, as shown in FIG. 6, the material tube 3' is set in a well-known diffusion welding device 6 at a predetermined position, and as shown in FIG.
The entire surface of 141P is covered with a pack material 7, and so-called 141P bonding is performed.

During the diffusion welding, the titanium foil 5 easily comes into contact with the ceramic inner tube 2 in a diffusion bath due to its active function.
It also spreads towards my father, waxing material 4.

On the other hand, the silver brazing filler metal 4 melts due to the high temperature and adheres to the carbon steel outer tube 1, and also melts to the titanium foil 5, and as a result, titanium diffuses into the ceramic inner tube 2, and the carbon steel outer tube 1.
and ceramic inner tube 2 are metallurgically coupled 6 via molten metal 8.

Then, when the diffusion welding is completed and the degree of tackiness decreases, the diameters of the outer tube 1 and the bath metal 8 are reduced, and a predetermined compression saw is applied to the ceramic inner tube.

This is because the degree of diameter reduction is small because the thermal expansion coefficient of the ceramic inner tube 2 is small.

After the diffusion welding is completed, both ends are appropriately cut to obtain the ceramic double tube 3 as shown in FIG.
When used in oil country tubular goods etc., the corrosion resistance is sufficiently grooved by the ceramic inner tube 2, the pressure resistance is sufficiently functioned by the carbon steel outer tube 1, and the edge UCP is prevented from chamfering due to the compressive residual stress mentioned above. Thermal behavior is small due to the small thermal expansion coefficient of ceramic.

It goes without saying that the embodiments of the invention of this application are not limited to the above-mentioned embodiments; for example, various embodiments can be adopted, such as the possibility of using other materials for the metal outer tube and the brazing material. .

It is also possible to use a brazing method using a sufficient amount of brazing material in consideration of the difference in thermal expansion between the inner and outer tubes 1 and 2, as in the embodiment shown in FIGS. 6 and 7.

According to the above-mentioned invention of this application, the ceramic inner tube is metallurgically bonded to the metal outer tube through the activity of titanium, so that they are completely and firmly bonded.
This brings about the remarkable effect that highly reliable operation is possible without any slipping or cracking.

In addition, the brazing material not only metallurgically connects the titanium and the metal outer tube, but also fills the space between the metal outer tube and the ceramic inner tube after titanium diffusion welding, and applies compressive stress to the ceramic inner tube after cooling. Therefore, an excellent effect is achieved in that no cracking occurs during operation.

Therefore, the advantages of ceramic's light weight and small coefficient of thermal expansion are taken advantage of, and in combination with the above-mentioned effects, the thermal behavior is small, and therefore the pipe has the advantage of being highly reliable and easy to construct and transport.

Therefore, in the production of this ceramic tube, two convex pieces of titanium are attached in advance to the outside of the ceramic inner tube, and diffusion welding is performed by interposing a brazing material on the outer side of the metal tube. As a result, the brazing filler metal would normally adhere to the ceramic inner tube, but through the activity of titanium, titanium diffuses into the ceramic and also into the brazing filler metal, and as a result, the brazing filler metal adheres to the ceramic inner tube. Excellent effects can be achieved by metallurgically bonding the metal outer tube.

Moreover, there is an advantage that these connections can be made all at once by diffusion welding.

[Brief explanation of the drawing]

Figure 1 is a partial sectional view of a conventional double ceramic pipe, and Figures 2 and below are detailed explanatory views of the invention of this application.
Figure 2 is an analysis diagram of the 6 parts of the material tube, Figure 6 is a partial cross-sectional view explaining diffusion 1, Figure 4 is an enlarged partial cross-sectional view of Figure 5, and Figure 5 is a double-view cross-sectional view of the ceramic. 6 and 7 are 1-dimensional views of other embodiments. 1...Outer tube, 2...Ceramic inner tube,
3″... Ceramic double tube, 8... Metallurgical bond (
Molten metal), 5...Titanium (??3), 4.
...Brazing filler metal Fig. 6 Fig. 7

Claims (2)

[Claims] (1) In a ceramic double tube in which a ceramic inner tube is bonded to a metal outer tube, a metallurgical bond is formed between the metal outer tube and the ceramic inner tube, and the titanium A ceramic double tube characterized in that is used as a binding material. (2) In a manufacturing method in which a double tube is obtained by metallurgically bonding a ceramic inner tube to a metal outer tube, a titanium layer is attached to the gold and outer tube through a brazing material, and the titanium A ceramic double layer characterized in that a ceramic inner tube is layered within the layer, and the ceramic inner tube and the metal outer tube are metallurgically bonded by heat treatment in a polymerized state and using the titanium as a bonding material. Car tube manufacturing method.