JPH08357Y2 - Ceramic interpolating metal pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a ceramic interpolating metal pipe used for a powder transport pipe or the like.

(Prior Art) For the purpose of improving the durability of a portion of a powder transportation pipe that is significantly worn due to contact with powder, conventionally, a pipe made of wear-resistant metal such as stainless steel or stellite has been used, or The inner surface of the metal pipe is lined with ceramic and used.

As a method of providing a ceramic layer in the inner layer of the metal layer,
There is a shrink fitting method, a fixing method with an adhesive, or a method using self-combustion reaction sintering, and when the pipe diameter is large, there is a method of attaching a ceramic fired tile with an adhesive.

Of these, a shrink fitting method and a fixing method using an adhesive are effective as a method for providing the ceramic layer on the inner layer of the small-diameter metal pipe.

(Problems to be solved by the invention) Since the conventional shrink fitting method is performed by applying the difference in the coefficient of linear thermal expansion of the pipes forming each layer, the dimensional tolerance is strictly controlled in order to increase the shrink fitting effect. There is a need. Nevertheless, the use temperature is limited to below the shrink fitting temperature. In the fixing method using an adhesive, it is technically difficult to fill the adhesive layer with a sufficient amount of the adhesive, particularly in the case of a long pipe. Furthermore, the operating temperature is limited, and the hot reliability is not always excellent.

In principle, the method utilizing self-combustion reaction sintering is difficult to apply to the curved pipe portion in principle, and the ceramic layer formed is not necessarily dense and has low reliability in wear resistance. In addition, the method of sticking the ceramic fired tiles with an adhesive tends to be affected by the construction technique of the adhesive, and the wear tends to progress at the joint between the type and the tile.

Further, the application of the shrink fitting method, the fixing method with an adhesive, and the method utilizing self-combustion reaction sintering is limited to the straight pipe. In addition, the method of sticking the ceramic fired tile with an adhesive has a limit in workability on the inner surface of the small diameter pipe.

Each of the methods described above requires technical precision or complicated steps.

Therefore, it has been desired to develop a metal pipe in which a ceramic layer is provided on the inner layer of a metal pipe having a small diameter or a curved pipe shape by a relatively easy and highly reliable method. Especially, since there is no method for applying a ceramic inner layer to the inside of a curved pipe having a small diameter, there is a great demand for a metal pipe in this field.

(Means for Solving the Problems) The present invention provides a metal pipe by forming a metal layer to be an outer layer by thermal spray deposition using a flame spray gun on the outer surface of a ceramic sintered body pipe forming an inner layer. It is a ceramic inserted metal pipe.

With the ceramic pipe set in a holding device and rotated, a metal wire or powder is spray-coated on the outer surface of the ceramic pipe by using a flame spray gun to form a metal layer. The thermal spraying conditions are determined by the thermal shock resistance of the ceramic pipe to be used, physical properties such as thermal expansion coefficient, the thermal expansion coefficient of the metal to be sprayed, thermal spraying workability and the like.

As shown in Table 1, by selecting the thermal spraying conditions such as the number of revolutions of the ceramic pipe, the cooling conditions, the gun moving speed, the thermal spraying distance, and the gas conditions, a sound metal layer can be thick-wall sprayed.

(Operation) As described above, according to the ceramic inserted metal pipe of the present invention, it is possible to easily provide a dense and highly wear-resistant ceramic layer, which has not been obtained by the conventional method, on the inner surface of the metal layer. Further, due to the manufacturing method, there is no restriction on the dimensional tolerance of the ceramic layer and no gap is formed between the ceramic layer and the metal layer, so that the reliability in use is high.

In addition, by forming two or more kinds of metal layers to be sprayed in layers, it is possible to control the stress generated at the joint between the ceramic layer and the metal layer. It can be easily applied to shaped pipes.

(Example 1) Fig. 1 shows a construction apparatus, and Table 2 shows construction conditions.

A sialon pipe 1 having an inner diameter of 15 mm, an outer diameter of 20 mm, and a length of 1000 mm was attached to a rotating device 2 and rotated at 430 rpm, and a stainless steel wire rod (SUS420J2) 4 was sprayed on the outer surface of the sialon pipe 1 using a flame spray gun 3. . The flame spray gun 3 was mounted on the moving device 5 and reciprocated in parallel with the length direction of the sialon pipe 1. Movement speed
Sprayed at 30 cm / sec. While spraying, the sialon pipe 1 was air-cooled by the air nozzle 6.

The thus-obtained metal layer with a wall thickness of about 10 mm (build-up sprayed part)
The adhesiveness to the sialon pipe was also good, and no peeling phenomenon was observed. In addition, since it has machinability and can finish the outer surface, it can be used as a structure even if the wall thickness is reduced to about 0.5 mm if necessary.

(Example 2) In a conventional scrap melting furnace, a triple pipe tuyere for injecting gas into the molten iron from below the molten iron bath surface is used.
It has a duct cross section as shown in the figure. That is, triple tube tuyere 7
Is a carbonaceous powder as a non-oxidizing gas from the inner pipe 8, an oxidizing gas from an annular gap 11 between the inner pipe 8 and the middle pipe 9 formed by the ribs 10, and an annular gap 13 between the middle pipe 9 and the outer pipe 12. A non-oxidizing gas for cooling is blown into the molten iron from below the molten iron bath surface. Conventionally, stainless steel pipes are all used for the triple pipe tuyeres 7.

As shown in Fig. 3 (a), inner diameter 15mm, outer diameter 20mm, length
A cladding 8 having a wall thickness of about 10 mm was provided on the outside of the 2000 mm sialon pipe 1 by the method of Example 1, and thereafter the rib 10 was machined as shown in (b) to manufacture a pipe 8.

The pipe 8 of the present invention comprises an inner sialon layer 1, an outer metal spray layer 14 and a rib 10 integrated with the metal spray layer 14. This was used as the inner tube of the triple tube tuyeres.

As a result, the inner surface wear amount of the conventional inner pipe was 0.01 mm / ton-coal.
However, the inner surface wear amount of the inner pipe of the present invention is 8 × 10 ^-4
It became less than mm / ton-coal, and the amount of wear was greatly reduced.

(Effect of the Invention) As described above, by using the ceramic-inserted metal pipe according to the present invention, the wear resistance is significantly improved as compared with the conventional metal pipe. Further, since the drawbacks of the conventional methods of providing the ceramic layer on the inner layer of the metal layer can be eliminated, new applications can be expected.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view of a method for manufacturing a ceramic inserted metal pipe according to the present invention, FIG. 2 is an explanatory view of a structure of a conventional triple pipe tuyere, FIG. 3 (a), FIG. 3B is an explanatory view of an example of use of the ceramic-inserted metal pipe according to the present invention for the inner pipe of the triple tuyere. 1: Sialon pipe, 2: Rotating device 3: Flame spray gun, 4: Stainless steel wire rod 5: Moving device, 6: Air nozzle 7: Triple pipe tuyere, 8: Inner pipe 14: Metal layer (buildup spraying part)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-63-45357 (JP, A) JP-A-57-67158 (JP, A) JP-B-49-32174 (JP, B1)

Claims (1)

[Scope of utility model registration request] 1. A ceramic-inserted metal pipe in which a metal layer is formed by thermal spraying on the outside of a ceramic sintered body pipe forming an inner layer to form a metal pipe.