JPS6379902A - Lining method for inner surface of tube - Google Patents

Abstract

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

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for lining the inner surface of a tube.

[Conventional technology]

The inner surface of the pipe is lined with a lining to enhance corrosion resistance, abrasion resistance, etc., depending on the intended use and conditions of use.

Examples of methods for lining the inner surface of the tube include a thermal spraying method in which a lining material is thermally sprayed and its droplets adhere to the inner surface of the tube;
Weld overlay method in which a bead of lining is formed on the inner surface of the tube by IG welding, etc., or melted lining material is injected into the tube while rotating the tube around its axis, and the inner surface of the tube is melted by centrifugal force. The centrifugal casting method, which coats the material with a solid layer and solidifies it, is used.

[Problem that the invention seeks to solve]

However, when using the thermal spray method, it is necessary to operate the thermal spray gun, when using the weld overlay method, it is necessary to operate the welding tools such as a welding torch, and when using the centrifugal casting method, it is necessary to insert a casting hopper into the pipe. Both of the above apply only to large diameter pipes and cannot be applied to small diameter pipes. Moreover, the lining layer formed by the thermal spraying method has the drawbacks of poor density and weak bonding strength with the inner surface of the tube, while the lining layer formed by the welding overlay method has the disadvantage that the lining layer is formed by the welding heat during bead formation. The melt penetration into the base material (pipe) is deep, making it difficult to form a thin lining layer.

Furthermore, when forming a lining layer by centrifugal casting, there is a problem in that many factors must be controlled.

The present invention solves the above problems, and regardless of the size of the pipe diameter,
The present invention aims to provide a method by which a healthy lining layer can be formed relatively easily.

[Means and effects for solving the problems] The method for lining the inner surface of a tube according to the present invention is to apply a lining layer on the inner surface of the tube to the surface of the core metal, which is the outer layer material and has been processed into an outer shape that corresponds to the inner shape of the tube. A thermally sprayed layer made of lining material is 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 hot isostatic pressure sintering is performed. The thermal spray layer on the surface of the core metal is bonded to the inner surface of the tube, and then the core metal is removed.

According to the present invention, first, a core metal processed into an outer shape corresponding to the inner shape of the target pipe is prepared, and a lining material to be a lining layer on the inner surface of the pipe is thermally sprayed onto the surface of the core metal, as shown in FIG. As shown in the figure, a thermal spray layer (2) is applied to cover the surface of the core metal (4).
’) is formed.

The thermal spraying material may be pure nickel, pure molybdenum, or Co-based alloy (for example, MO: 24 to 35%) depending on the material properties required for the lining layer (e.g., corrosion resistance, wear resistance, etc.).
, Cr: 4-20%, Si: 5% or less, balance Co)
, Ni-based self-fluxing alloy (e.g. Cr: 4-20%,
B: 1 to 4%, Si: 5% or less, balance Ni), etc. metals,
Alternatively, ceramics such as alumina, chromium carbide, and silicon nitride, or mixtures of metals and ceramics (for example, mixtures of Co-based alloys or Ni-based self-fluxing alloys and tungsten carbide, etc.) are used. On the other hand, since the core metal is to be removed eventually, an inexpensive and easily machinable material such as SSL material may be used.

The lining material may be made of a combination of different materials if desired, for example, as shown in Fig. 1, a corrosion-resistant lining material may be applied to the (al) area and a wear-resistant lining material may be applied to the (b) area. can.

When a metal or a mixture of metal and ceramic is directly sprayed onto the surface of the core metal as a lining material, the sprayed layer (lining layer) will diffuse the core metal components during the subsequent hot isostatic pressure sintering process. may be stained by lη. As a countermeasure for this, as shown in Figure 2, the core metal (4)
It is effective to first thermally spray a ceramic such as alumina on the surface as a base layer (3), and then to laminate a thermally sprayed layer (2') made of a lining material on top of the base layer (3). The base layer (3) is made of core metal (
4) is removed together with the core metal. Note that if the thermal sprayed layer (2'), which will become a lining layer, is placed on top of the as-sprayed base layer (3), the unevenness on the surface of the base layer (3) will be transferred to the inner surface of the lining layer. It is preferable to finish the surface of the base layer (3) to a predetermined roughness by machining and then thermally spray the lining material. In this way, polishing of the lining layer after removing the metal core can be omitted.

After the surface of the core bar (4) is coated with the sprayed layer (2') as described above, the tube (1), which is the outer layer material, is fitted as shown in FIG. If the core metal (4) has an irregular shape, for example, in the case of a core metal with a bulging large diameter part (41) in the middle part as shown in Fig. 4, the outer layer material (1) should be It is sufficient to divide the parts (11) and (12) into parts, fit them together, and seal the abutting surfaces of both parts with a suitable sealing material (6). The mating surface is
In the subsequent hot isostatic pressing sintering process, the materials are sufficiently bonded by diffusion bonding.

In addition, to prevent deformation during hot isostatic pressing and sintering,
And in order to easily accomplish the sintering process, the outer layer material (1)
Prior to fitting, the surface of the sprayed layer (2') and the inner surface of the outer layer material (1) are machined so that the clearance between the surface of the sprayed layer (2') and the inner surface of the outer layer material (1) is 0.1 mm or less. It is desirable to apply the following.

The outer layer material (1) is fitted, the interior of the sprayed layer (2') and the gap between the sprayed layer (2') and the outer layer material (1) are vacuum degassed, and the M materials (5, 5) are welded to both ends. (W) Close and seal;
It is then subjected to hot isostatic pressure sintering treatment. Vacuum degassing and sealing are performed to successfully achieve hot isostatic pressing sintering treatment, densify the sprayed layer (2'), and spray the sprayed layer (2')
This is to ensure perfect bonding between the outer layer material (1) and the outer layer material (1).

Under high pressure and heating conditions in the hot isostatic pressing sintering process, the sprayed layer (2') is highly densified, and the interface between the sprayed layer (2') and the outer layer material (1) is , a strong bonding relationship is formed by solid phase bonding.

After completing the hot isostatic pressing sintering process, the core bar (4) is removed by machining. If a ceramic base layer (3) is formed on the core bar (4), or if the lining layer (2) is made of ceramic, it is also possible to pull out the core bar (4). After removing the core metal in this way,
If necessary, by polishing the inner surface of the densified thermal sprayed layer (2), the densification covering the outer layer material (1) and its inner peripheral surface can be achieved as shown in Figures 5 and 6. A tube is obtained having a lining layer (2) which is a thermally sprayed layer.

〔Example〕

Real” I pull 1 SS41 core metal (outer diameter = 8φ, length: 1507!, rim l
) as a lining material on the surface of Co-based alloy (Mo: 28
．． 5%, Cr: 8.5%, Si: 2.6%, balance 00)
After forming a sprayed layer and machining the surface of the sprayed layer, a 345C steel circular tube (inner diameter: 10φ, outer diameter = 32φ,
Length: 1507! , ■), and after vacuum degassing and sealing both ends with lid material, temperature: 1200°C 1 pressure crab 1
It was subjected to hot isostatic pressure sintering treatment at 500 kg f /ct and holding time: 211 r. After sintering, the core material is removed and the outer surface is machined to create an outer diameter of 30φ and an inner diameter of 10mm.
A tube with φ, length: 15ON, lining layer thickness: approx.] mm was obtained. It was confirmed that the lining layer was dense and the interface with the outer layer material was completely bonded by in-phase bonding.

Example 2 SS4] core metal (outer diameter = 8φ, length: l5Off,
am) alumina as a lining material on the surface? 8 n
・After forming one layer and machining the surface of the sprayed layer, add a 345G steel circular tube (inner diameter = lOφ, outer diameter: 3
2φ, length: 150fi, n), and after vacuum degassing, seal both ends with lid material, temperature: 1250°C, 1 pressure crab 1500kg f/ctl, holding time: 2Hr.
Hot isostatic pressing sintering was performed. After sintering, the core metal is removed and the outer surface is machined to create an outer diameter of 30φ and an inner diameter of 10mm.
φ, length: 150A.

A tube with a lining layer thickness of approximately 111 was obtained. It was confirmed that the lining layer was dense and the interface with the outer layer material was completely bonded by solid phase bonding.

Core metal made by Inutake Kanshu 5S41 (outer diameter near φ, length: 15ON, +
An alumina sprayed layer with a layer thickness of approximately 0.511 mm was provided as a base layer on the surface of +n), and after polishing the surface, a Co-based alloy (Mo: 2f3.5%, Cr) was applied as a lining material.
: 8.5%, Si: 2.6%, balance Co), and after machining its surface, a 545C steel circular tube (inner diameter: 10φ, outer diameter = 32φ, length :1507
! , ms), and after vacuum degassing, cover both ends tightly with a lid.
f/ca.

Holding time: Hot isostatic pressure sintering was performed for 2 hours.

After sintering, the core metal and base layer were removed, and the outer surface was subjected to mechanical wave processing to obtain a tube having an outer diameter of 3oφ, an inner diameter of 10φ, a length of 15ON, and a lining layer thickness of about 11.

The lining layer was dense, and the interface with the outer layer was found to be strongly connected by in-phase bonding.

〔Effect of the invention〕

The method of the present invention includes forming a sprayed layer of lining material on the core metal,
We fitted the tube as the outer layer material into this and bonded the lining layer to the inner surface of the tube by hot isostatic pressure sintering, so regardless of the size of the tube, even small diameter and long tubes can be lined. The lining layer can be easily formed, and the lining layer is dense and the bond to the inner surface of the tube is strong. The method of the present invention is useful as a wear-resistant and corrosion-resistant lining method for the inner surfaces of various cylinders and pipes.

[Brief explanation of the drawing]

1 to 6 are cross-sectional explanatory views of embodiments of the method of the present invention. ■=Pipe, 2nd lining layer, 2' lining material sprayed layer, 3: Base layer, 4: Core bar.

Claims (2)

[Claims] (1) After forming a sprayed layer of lining material that will become the lining layer on the inner surface of the tube on the surface of the core metal, which is the outer layer material and has been processed into an outer shape that corresponds to the inner surface shape of the tube, the tube is fitted into this, The gap between the tube and the core metal is vacuum degassed, both ends of which are sealed, and then subjected to hot isostatic pressure sintering treatment to bond the tube and the thermal sprayed layer on the surface of the core metal. A method for lining the inner surface of a tube, characterized by removing. (2) A ceramic sprayed layer is formed as a base layer on the surface of the core metal, a sprayed layer made of lining material is laminated on top of it, and after hot isostatic pressure sintering treatment, the core metal and base layer are laminated. 2. The method for lining an inner surface of a tube according to item 1 above, characterized in that a certain ceramic sprayed layer is removed.