JPS5813488A - Production of metal clad ceramic pipe - Google Patents

Abstract

PURPOSE:To produce a metal clad ceramic pipe which lends itself to various applications over a wide range by cladding a ceramic material with a metallic by the use of a hot hydrostatic pressing method to overcome the disadvantages of the ceramic material. CONSTITUTION:A metallic pipe 3 for insertion is disposed on one inside surface of a metallic pipe 2 to be clad on the outside surface of a ceramic pipe 1, and the top end of the space is covered with an upper ring 4' having a pipe 5 for deaeration. The spacing formed of respective metallic members is sealed tightly by welding or the like. After a evacuation is performed through the pipe 5 at room temp. or elevated temp., the pipe 5 is closed, butt welded and welded to maintain the airtightness in the inside. The assembly is subjected to a hot hydrostatic pressing (HIP) treatment. It the pipe 1 and the pipes 2, 3 subjected to the HIP treatment are removed of the pipe 3 and rings 4, 4' under atm. pressure, the ceramic pipe clad with the metallic pipe 2 on the outside surface is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a metal clad ceramic pipe using a hot isostatic pressing method (hereinafter referred to as HIP method).

Ceramic materials have attracted attention as high-temperature structural materials due to their superior heat resistance, chemical resistance, and wear resistance, and their use is being developed.However, as they are brittle materials, the crack propagation speed is is fast, and destruction progresses instantly.

(2) Since machining is difficult, it cannot be combined with metal members or other ceramic members.

(3) Many ceramic materials have a high porosity of 10 to 30%, so low viscosity fluids such as water and gas can penetrate or pass through the pores. The uses of pipes are very limited, and pipes with sufficient performance have not yet been obtained.

Therefore, various materials have been conventionally used to compensate for the drawbacks of such ceramic materials. For example, ceramic materials currently being used or being developed as heat exchanger materials include SiC pipes and glass made by reaction sintering. However, although these materials have a certain degree of heat resistance, they suffer from brittle fracture as described above, and in addition to being able to instantly form large racks, they also have the disadvantage that they are difficult to connect with other parts.
In addition, as for pipes for transporting high-temperature gases and corrosive gases, there are almost no ceramics used for transporting high-temperature gases, and metals such as lead or resin are used in graphite pipes for transporting corrosive gases. Impregnated products are often used, but the temperature at which they are used is only a hundred and a few dozen degrees Celsius or less, making them practically unsuitable for the current high-temperature transportation. Furthermore, wear resistance is often required for nozzles for ejecting powder and granular materials, spinning nozzles, etc.
The fixation to the metal fittings is simply by pressing or by shrink fitting, which exposes the drawback of being vulnerable to vibration.

In particular, the bonding of metal and ceramic has traditionally been one of the most difficult technical issues, and although many years of research have been carried out, no effective means have been found, and only recently has ceramics been developed. Fe-Ni whose thermal expansion coefficient is similar to that of the material
We have just found the beginning of a solution to the problem of adhesion by high-temperature brazing using a -Co alloy.

In response to the current situation, the present inventors have made extensive studies to eliminate each of these drawbacks, and as a result, have recently achieved remarkable effects on the removal of casting defects, metal joining, and densification. The use of HIP method, which is attracting attention for its effectiveness, 1, 5
In addition to discovering the drawbacks of ceramic materials, cladding with metal materials has been widely used.

We have achieved the production of metal-clad ceramic pipes that can be used in a wide range of applications.

That is, the present invention solves the drawbacks of ceramic materials by cladding them with metal materials, and can be used in a wide range of fields such as pipes for heat exchangers, pipes for transporting high-temperature gases and corrosive gases, pipes for transporting slurry, nozzles, and pipes for burners. In other words, to provide an effective metal clad ceramic pipe and a method for manufacturing the same, which can be easily used as a member that requires heat resistance, thermal shock resistance, airtightness, abrasion resistance, and corrosion resistance. The object of the present invention is to provide a metal clad ceramic pipe that can be connected to other materials using screws, etc., and a method for manufacturing the same.

Therefore, it is an object of the present invention to use a ceramic pipe having an uneven outer surface, to clad a metal pipe on the outer surface, and to use a pipe or solid material on the inner surface made of a metal that can be welded to the metal pipe material. The metal pipes or solid material and the outer metal pipe are joined and sealed at least at both ends, and then HIP is applied.
This is achieved by processing to crimp the outer metal pipe to the outer surface of the ceramic pipe and removing the inner metal pipe or solid material.

Here, the use of the HIP method in the production of clad products is proposed by the applicant in the production of clad steel plates, for example, in which a steel plate is used as a base material and a metal plate is clad on this. Although the method of the present invention uses a ceramic pipe as the base material, no proposal has been made for cladding made of such dissimilar materials, and the present invention is the focus of this invention. It is.

Hereinafter, specific embodiments of the method of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an example of a ceramic pipe used as a base material in the present invention, and the outer surface of the pipe (+1) has minute irregularities formed as shown in the figure. In this case, an appropriate uneven shape is selected depending on the materials of the base ceramic pipe and the cladding metal pipe, but even if the unevenness has a difference of several millimeters, HIP processing can completely complete the process without any gaps. can be clad. The ceramic pipe +11 having such an uneven outer surface can be easily manufactured by known means such as spraying ceramic powder onto a ceramic pipe by shot blasting or the like.

The ceramic pipe (1) can be made of not only oxide ceramics such as Al2O3 and 5iAlON, but also non-oxide ceramics such as Si3N4 and SIC.
Also included are mixtures of oxides such as Mg or nitrides as sintering aids. When manufacturing a clad pipe using the ceramic pipe as a base material,
First, as shown in FIG. 2, the ceramic pipe f1+ is fitted between the metal pipe (2) to be clad, the metal pipe (3) for insertion, and the inner and outer metal pipes f21+31 to seal the lower end. The ceramic pipe (4) is placed in the space formed by the ceramic pipe (4).
1) the metal pipe (2) to be clad on the outer surface;
On the other hand, a metal pipe for insertion □-: (3) is arranged on the inner surface, and the upper end of the space is covered with an upper ring (4') having a degassing pipe (5). Make the gaps airtight by welding, etc.

Therefore, the outer metal pipe (2) and the inner metal pipe (
3) is preferably a metal that can be welded to each other.

The material of the metal pipe (3) cladding the ceramic pipe (1) is generally Fe, %Ni,
Ti.

A metal containing Cr or one of these as a main component is used, while a metal with a large coefficient of thermal expansion is used as the material for the inner metal pipe (3) from the viewpoint of removal after HIP treatment. Ru.

The structure shown in FIG. 2 thus arranged and made airtight is then evacuated as a whole through the degassing pipe (5) at room temperature or at high temperature to remove any air remaining inside. After removing adhering moisture, etc., the degassing pipe is crushed and forge-welded, as in the normal HIP process, and further welded to ensure that the internal airtightness is maintained.

Note that this degassing operation is not necessarily essential in the present invention, but may be used when it is desired to keep the interface between the ceramic pipe +1) and the cladding metal pipe (2) clean, or when
Implementation is preferable and effective when reliability of IP processing is important. In addition, if it is difficult to clean the entire interior even with a long degassing pipe, put getter material such as Fi or Zr inside.
It may be removed after the HIP process.

In particular, when the wall thickness of the ceramic pipe (+) to be clad is not very thick and is relatively thin, the outer metal pipe (2) to be clad and the inserted metal pipe (3) are connected with a ring as described above. +41+4') may be directly welded at both ends.

After completing the above operations, the ceramic pipe (1), the outer metal pipe (2), and the inner metal pipe (
The structure consisting of 3) is then loaded into a HIP device and subjected to HIP treatment using a known method. HIP processing is
It is necessary to maintain the temperature and pressure at which the cladding metal material can be sufficiently plastically deformed and bonded, and the processing time is long enough to ensure sufficient diffusion bonding between the base ceramic material and the cladding metal material in a state in which they are in close contact. must be applied. In particular, HIP pressure and temperature are closely related to the thickness of the base ceramic material and the cladding metal material.
At HIP temperature, the thicker the clad metal material, the greater its deformation resistance, so a high HIP pressure is required to bring both materials into close contact. The thicker the cladding, the higher the HIP temperature required to soften the cladding material and make it easier to adhere.

However, increasing the HIP temperature and HIP pressure increases the temperature and pressure increase time as well as the temperature and pressure decrease times.
HIP processing requires a long time, which not only reduces productivity but also increases costs, so these HIP processing conditions should be selected appropriately depending on the ceramic material, cladding metal material, and their thickness. It's advantageous.

The ceramic pipe f thus completed the HIP treatment.
i1, metal pipe f21 f3) is taken out from the device under atmospheric pressure and the metal pipe for insertion (3) and ring (t) f41 are removed, resulting in a ceramic pipe whose outer surface is clad with metal pipe (2). is obtained. In this case, if a material with a large coefficient of thermal expansion is used for the metal pipe (3) for insertion as described above, the metal pipe (3) can be removed more easily than the ceramic pipe +1) due to the difference in coefficient of thermal expansion. This is suitable. Another method is to provide a draft angle to the metal pipe (3) for insertion in order to facilitate removal.

Generally speaking, metal has a larger coefficient of thermal expansion than ceramic, so the metal-clad ceramic pipe manufactured by the method of the present invention has compressive stress in the circumferential direction, and the clad metal has a higher coefficient of thermal expansion than ceramic. The fact that tensile stress remains is the same as in the case of firing. However, since the clad metal flows into the uneven part formed on the outer surface of the f (ceramic pipe t1 plastically deformed by IP treatment), there are substantially uneven parts at the interface between the ceramic pipe +1+ and the clad metal. There are no gaps left, and a much stronger bond is obtained than in the case of firing.

Therefore, as mentioned above, even if the irregularities on the outer surface of the ceramic pipe are several millimeters, a cladding with no gaps can be obtained by the HIPIP treatment.

In addition, in the above description, the case where the insert material is a metal pipe has been described, but the metal member inserted inside the ceramic pipe is not limited to a metal pipe, but it is also possible to use a solid material.

In this case, as shown in FIG. 3, a ceramic pipe (1) with a solid material (3') inserted therein is inserted into a can-shaped capsule (2') made of cladding metal, H
IPIP processing is possible.

As described above, the method of the present invention involves forming irregularities on the outer surface of a ceramic pipe, placing a metal material cladding on the outer surface, and placing an insert material on the inner surface to reliably seal the gap between the two, followed by HIPIP treatment. Since this is a method of crimping a metal pipe onto the outer surface of a ceramic pipe, it is possible to easily clad a ceramic pipe with a high porosity with 1"9 metal, and it also provides a much stronger bond than when sintered. This has the remarkable effect of providing a pipe made of ceramic and metal cladding, which has been considered difficult in the past.

Moreover, as mentioned above, the method of the present invention utilizes the HIP method for cladding, so that the ceramic pipe is strongly clad with metal, and the ceramic base material itself is also densified due to the densification effect, making the Talarado pipe Even when used to transport low-viscosity fluids, it completely prevents the fluid from penetrating the ceramic, achieving high performance that is incomparable to cladding made simply by hot compression or compression bonding.

Furthermore, since the outside of the ceramic pipe obtained by the method of the present invention is clad with metal, even if the ceramic pipe were to break, the ductility of the outside metal would cause the entire pipe to break instantly. Will not fall apart and therefore even with high pressure fluid inside.
It does not break explosively; the weakest part of the cladding metal ruptures ductilely, allowing fluid to leak through a small hole without erupting.

Moreover, the clad metal parts can be easily machined to thread, etc., making it easy to connect and combine with other parts, and it is also possible to attach flanges to both ends of the clad material used. It is also easy to add ceramic pipes one after another.

Since the ceramic pipe produced by the method of the present invention is clad with metal, it has advantages such as airtightness, and although it is currently recognized for its excellent properties such as heat resistance,
The significance of the present invention is extremely significant, as it enables application to various fields of use of ceramics, whose practical application has not necessarily progressed sufficiently due to drawbacks such as brittle fracture.

The metal clad ceramic pipe according to the present invention is suitable for use in the aforementioned pipes for heat exchangers, pipes for transporting high-temperature gases and corrosive gases, pipes for transporting slurry, powder jet nozzles, spinning nozzles, burner pipes, etc. However, the method of the present invention can be applied not only to pipes but also to ring members whose diameter is larger than their length, and similar effects can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of a ceramic pipe used as a base material in the method of the present invention, Fig. 2 is a cross-sectional schematic diagram showing an example of the arrangement of each pipe during processing in the method of the present invention, and Fig. 3 FIG. 2 is a schematic cross-sectional view showing another embodiment of each pipe arrangement state of the method of the present invention. +1)...Ceramic pipe, (2)...Metal pipe for cladding, (3)...Metal pipe for insertion, (3
)...Medium body for interpolation, +41+41...Ring,
(5) Deaeration pipe, patent applicant Kobe Steel, Ltd. 15- Figure 3

Claims (1)

[Claims] 1. A metal pipe made of a cladding material is arranged on the outer surface of a ceramic pipe having an uneven outer surface, and a metal pipe or solid material that can be welded to the metal is arranged on the inner surface. , the metal pipe or solid material is joined to the outer metal pipe at least at both ends thereof by welding and sealed, and then hot isostatic pressing is performed to press the outer metal pipe to the outer surface of the ceramic pipe. and then removing the inner metal pipe or solid material to obtain a metal clad ceramic pipe. When joining, a degassing section communicating with the gap space formed by each metal member is provided, and residual air, attached moisture, etc. in the space are deaerated and removed at the time of sealing. Manufacturing method of metal Talarad ceramic pipe 3, Ceramic Hypka Al2O3, Si3N4.5
Claim 1 or 2, which is a pipe whose main component is one selected from the group consisting of iCXSiAlON.
Method for manufacturing metal clad ceramic pipe described in Section 4,
The outer metal pipe to be clad is FeXNiXTi. A method for manufacturing a metal-clad ceramic pipe according to claim 1, 2, or 3, which is a pipe made of Cr or a metal containing Cr as a main component.