JPS6380916A - Ceramic lining method for pipe inner face - Google Patents

Abstract

PURPOSE:To form a layer having a good resistance against a crack and separation on an inner face of a pipe by fitting into the pipe a ceramic lining layer and intermediate layer with their thermal spraying lamination in order on the surface of a core metal and removing the core metal after joining a welding layer each other by sintering with its working in a vacuum sealing state. CONSTITUTION:The ceramic thermal spraying layer 2' (alumina, etc.) becoming a lining layer 2 is formed with the thermal spraying on the surface of the core metal 4 worked in the external shape corresponding to the inner face shape of a pipe and the thermal spraying layer 3' (Fe-Ni alloy, etc.) becoming the intermediate layer 3 having the prescribed thermal expansion coefficient is laminated thereon with the thermal spraying. The intermediate thermal spraying layer 3' is subjected to a machining so as to make the clearance with the inner face of the outer layer material 1 of the pipe <=about 0.1mm and the core metal 4 is fitted inside the outer layer material 1. The space between the core metal 4 and outer layer material 1 is subjected to a vacuum deaeration, sealed with the thermal spraying of a cover material 5 to both ends, and the thermal spraying layer 3' and outer layer material 1 are integrated with joining by elaborating each thermal spraying layer 2', 3' with a hot hydrostatic pressure sinter treatment. The core metal 4 is then removed by machining and the outer layer material 1 is machined by grinding the thermal spraying layer 2' if necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a ceramic lining layer on the inner surface of a tube.

[Conventional technology]

Depending on the purpose and conditions of use, pipes are lined with a lining to protect and strengthen the inner surface of the pipe. Cerami Tsuku is a lining material with excellent corrosion resistance, abrasion resistance, heat resistance, etc.

As a method for forming a ceramic lining on the inner surface of a tube, there is a method in which ceramic lining powder is used as a thermal spraying material and is sprayed onto the inner surface of the tube using a thermal spray gun.

[Problem that the invention seeks to solve]

However, if we attempt to directly form a ceramic lining layer on the inner surface of a tube using thermal spraying, the applicable tubes are limited to large-diameter tubes due to the operation of the thermal spray gun. It is difficult to form.

In addition, there are no problems with ceramic-lined pipes when used at room temperature, but under conditions of use where high temperatures or thermal shocks are applied, the lining layer may crack or crack due to the large difference in thermal expansion coefficient between ceramic and metal. Peeling occurs, and the function as a lining layer is significantly impaired. As a countermeasure, it is effective to create a gradient in the coefficient of thermal expansion by interposing an intermediate layer between the inner surface of the tube and the ceramic lining layer, which has a coefficient of thermal expansion between the two. It is more difficult to perform such multilayer linings.

The present invention has been made to solve the above problems.

[Means and effects for solving the problems] The ceramic lining method for the inner surface of a tube of the present invention includes applying a ceramic lining layer to the inner surface of the tube via an intermediate layer having a coefficient of thermal expansion between that of the tube and the ceramic lining layer. In the forming method, a ceramic sprayed layer is formed as a lining layer on the inner surface of the tube on the surface of a core metal processed into an outer shape that corresponds to the inner surface shape of the tube as the outer layer material, and a predetermined intermediate layer is formed on the upper surface of the ceramic sprayed layer. A thermally sprayed layer consisting of an intermediate layer material having a coefficient of thermal expansion of 1
A layer or two or more layers are formed, a tube is fitted into this, the space between the tube and the core metal is vacuum degassed, and both ends are sealed, and then subjected to hot isostatic pressure sintering treatment to form the inner surface of the tube. The method is characterized in that the interface between the thermally sprayed layer and the thermally sprayed layer and the interface between the thermally sprayed layers are bonded, and then the core bar is removed.

According to the present invention, first, a core bar processed into an outer shape corresponding to the inner shape of the target tube is prepared, and a ceramic lining material to be a lining layer on the inner surface of the tube is thermally sprayed onto the surface of the core bar. By thermally spraying the intermediate layer material that will become the intermediate layer on top, the thermal sprayed layer (2') that will become the lining layer and the thermal sprayed layer ( 3') are laminated to a predetermined thickness.

The ceramic used as the lining material is appropriately selected from alumina, zirconia, chromium carbide, silicon nitride, and other known ceramics depending on the use and required characteristics of the pipe.

As the intermediate layer material, an appropriate metal or a mixture of metal and ceramic powder is used depending on the thermal expansion coefficient of each of the outer layer material of the tube and the lining layer. For example, Fe
-The thermal expansion coefficient (α) of Ni alloy (Invar) is
Content; at 25 to 36at%, it constantly changes over a wide range from lX10-6 to 16XlO-6 layer ℃,
By adjusting the Ni content, the intermediate layer material can be formed with an arbitrary thermal expansion coefficient. In addition, when using a mixture of ceramic and metal, the coefficient of thermal expansion changes depending on the amount of ceramic blended, so as shown in the examples below,
An intermediate layer having a desired coefficient of thermal expansion can be formed depending on the amount of ceramic added. Note that the intermediate layer is not limited to one layer, and if desired, two or more types of intermediate layer materials with different coefficients of thermal expansion may be used, and two or more intermediate layers may be laminated by thermal spraying them in the order of the coefficients of thermal expansion. may form.

As mentioned above, the ceramic sprayed layer (2') which is the lining material is formed on the surface of the core bar (4), and the desired number of sprayed layers (3') which are the intermediate layer material are laminated thereon by thermal spraying. , second
As shown in the figure, the tube (1), which is the outer layer material, is fitted. When fitting the outer layer material (1), the inner surface of the outer layer material (1) and its It is desirable that these surfaces be machined so that the clearance between the inner surface and the surface of the sprayed layer (3') of the intermediate layer material is 0.1 nm or less. Note that the core bar (4) has a bulging large diameter part (
41), the outer layer material (1
) is divided in the radial direction at the part corresponding to the large diameter part, fitted as a split mold with parts (11) and (12), and the abutting parts of the two are sealed with an appropriate sealing material (6). good. The abutting surfaces are completely bonded by solid state bonding during subsequent hot isostatic pressing and sintering.

After fitting the outer layer material (1) into the core metal (4),
) and the outer layer material (1), the lid material (5, 5) is attached to both ends by welding (w) and sealed, and then subjected to hot isostatic pressure sintering treatment. The purpose of vacuum degassing and sealing at both ends is to successfully accomplish hot isostatic pressing sintering.

Under the high pressure and heating conditions in the hot isostatic pressing sintering process, each sprayed layer (2') (3') becomes denser, and the interface between each sprayed layer and the outer layer material between the sprayed layer (3') and the outer layer material. The interface (1) is firmly bonded and integrated by solid phase bonding.

After completing the hot isostatic pressure sintering process, the core bar (4) is removed. The core metal (4) can be removed by machining or by drawing. After removing the core metal (4), if necessary, the inner surface of the densified sprayed layer (2') is polished, and the outer layer material (1) is machined as appropriate, as shown in Fig. 4. As shown in FIG. 5, the inner surface of the outer layer material (1) has an intermediate layer (3
) a tube coated with lining N(2) is obtained.

〔Example〕

Completed construction work Core metal (made of SS41, outer diameter: 10φ, length: 150/.

Alumina ceramic (A1203) is thermally sprayed as a lining material on the surface of the 345C carbon steel powder and alumina powder. 20% by weight, 40
Three types of mixed powders adjusted to % by weight and 60% by weight were used, and three thermal sprayed layers were laminated by thermal spraying in descending order of alumina content. After machining the outermost surface of the sprayed layer, a 345C carbon steel circular tube (outer diameter: 32φ, inner diameter: 15φ, length: 150A, ms) is fitted as the outer layer material (
Clearance 20.1 degrees or less). After vacuum degassing between the outer layer material and the core metal, lid materials are welded to both ends to seal, and hot isostatic pressure sintering (temperature: 1250°C, pressure crab 1500k)
g f / cnl, retention time: 2 Hr). After sintering, the core metal was removed and the surface was machined to produce a tube with an outer diameter of 30φ and an inner diameter of 10φ.

The thickness of each layer of the obtained tube was as follows: outer layer material: 8.5 mm;
The thickness of the first intermediate layer is 0.5 mm, the second intermediate layer is 0.5 mm, the third intermediate layer is 0.5 wm, and the lining layer is 1. Moreover, the thermal expansion coefficient of each layer is as follows.

Outer layer (S45C carbon steel circular tube): α=14X1f16/℃ Intermediate layer (S45C+ A j! 203) First intermediate layer (
Aff□03:20%) α= 12.8 X 10-h/'C second intermediate layer <A
izo*: 40%) α-11,6X10-”/”C Third intermediate layer (A7!zch: 60%) α=10.4X10-’/”C Lining layer (AAzOt) α=8 Xl0-”/ 'C It was also confirmed that each intermediate layer and lining layer were sufficiently densified, and that the interfaces between each layer and between the intermediate layer and the outer layer material were completely adhered by solid phase bonding.

Fusekimata core metal (made of SS41, outer diameter: 10φ, length: 1507!
.

Alumina ceramic (AlzOi) is thermally sprayed as a lining material on the surface of the thermally sprayed layer.
As an intermediate layer material, Nl content is 28at%, 28°5
Three types of Ni--Fe alloys of 29 at % and 29 at % were thermally sprayed in descending order of Ni content to form three thermally sprayed layers. After machining the surface of the sprayed layer, a 345C carbon steel circular tube (outer diameter: 32φ
, inner diameter: 15φ, length: 150I2. Insert (
Clearance: 0. After vacuum degassing between the outer layer material and the core metal, and sealing by welding a cover material to both ends, hot isostatic pressure sintering (temperature: 1350℃, pressure crab 150℃) is performed.
0 kg f/ctM, retention time: 2 Hr). After sintering was completed, the core metal was removed and the surface was machined to produce a tube with an outer diameter of 30φ and an inner diameter of 1oφ.

The thickness of each layer of the resulting tube is: outer layer material: 8.5 am;
1st middle layer: 0.5 baking soda, 2nd middle layer 20.5 fins, 3rd
Intermediate MA: 0.5 m, lining layer: 11■. Moreover, the thermal expansion coefficient of each layer is as follows.

Outer layer (345C carbon steel circular tube): Sae = 14X10-'/'C Intermediate layer (Ni-Fe alloy) First intermediate H (N 128 at%) α = 12 X 10-'/℃ Second intermediate layer (N i 28.5at%) α=10.5x
lO-”/”c Third intermediate layer (N i 29at%) α=9 Xl0-”/”C Lining layer (Al2O2) α=8 Xl0-b/°C Each intermediate layer and lining layer are sufficiently dense. It was also confirmed that each layer and the interface between the intermediate layer and the outer layer were completely bonded by solid phase bonding.

〔Effect of the invention〕

The method of the present invention does not directly spray the lining material and intermediate layer material onto the inner surface of the tube, but instead forms these sprayed layers on the core metal, fits the tube, and performs hot isostatic pressure sintering to form the inner surface of the tube. Since the lining layer and the intermediate layer can be easily formed on the inner surface of a small diameter and long tube, regardless of the size of the tube. Moreover,
The lining layer and intermediate layer have little porosity, which is typical of thermally sprayed layers, and are extremely dense, and the bonding between each layer and the inner surface of the tube is strong. Furthermore, since the intermediate layer provides a gradient of thermal expansion coefficient between the tube and the lining layer, it has good resistance to cracking and peeling even under usage conditions that are subject to high temperature heating and thermal shock. We are prepared.

Therefore, the method of the present invention requires corrosion resistance, wear resistance, etc.
It is useful as a lining method for various cylinders and pipes that are subject to high temperatures and thermal shock.

[Brief explanation of the drawing]

1 to 5 are cross-sectional explanatory views of embodiments of the present invention. ■ = outer layer material, 2nd lining layer, 3: intermediate layer, 4: core metal, 2' 2nd lining material sprayed layer, 3': intermediate layer material sprayed layer.

Claims (1)

[Claims] (1) A method for lining the inner surface of a tube in which a ceramic lining layer is formed on the inner surface of the tube through one or more intermediate layers having a coefficient of thermal expansion intermediate between that of the tube and the ceramic lining layer. A thermally sprayed layer made of a ceramic material is formed on the surface of the core metal, which has been processed into an outer shape corresponding to the shape, and is made of a ceramic material, which becomes the lining layer on the inner surface of the tube, and an intermediate layer having a predetermined coefficient of thermal expansion is formed on the upper surface. After laminating one or two or more thermally sprayed layers made of material, fitting a tube into this, vacuum degassing between the tube and core metal, and sealing both ends, hot isostatic pressure sintering treatment is performed. A ceramic lining method for the inner surface of a tube, characterized in that the tube is bonded to a thermally sprayed layer in contact with the inner surface thereof, and an interface between the thermally sprayed layers is bonded to each other, and then a core metal is removed.