JPH0196363A - Manufacture of pipe lined with metal internally and externally - Google Patents

Abstract

PURPOSE:To form metallic lining layers excellent in corrosion resistance and wear resistance on the internal and external surfaces of a metallic pipe, respectively, by forming metallic powder layers suited to specific purposes on the internal and external surfaces of a metallic pipe while rotating the pipe at high speed and simultaneously applying heating to the above metallic powder layers so as to subject the layers to melting, diffusion, and adhesion. CONSTITUTION:A metallic pipe 1 is supported by a turning gear 11 by means of supporting members 12, and a thermal spraying gun 2 and a heating device 8 are disposed outside the metallic pipe and a metallic powder-supply pipe 5 is put into the above pipe. While rotating the metallic pipe 1 by means of the turning gear 11 so that centrifugal force is regulated to >=2G at the internal surface and <=7G at the external surface, a metallic powder 3 is thermally sprayed from the thermal spraying gun 2 to form a metallic powder layer 4 on the external surface of the metallic pipe. Simultaneously, a metallic powder 6 is fed through the metallic powder-supply pipe 5 to the internal surface of the metallic pipe to form a metallic powder layer 7 by means of centrifugal force and heating is applied from the outside of the metallic pipe to both metallic powder layers 4, 7 while moving the heating device 8 to subject the above metallic powder layers 4, 7 to melting, diffusion, and adhesion, by which the metallic lining layers 9, 10 excellent in resistance to wear and corrosion can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a metal tube in which a metal lining layer having high corrosion resistance, wear resistance, etc. is formed on the inner and outer surfaces of the metal tube.

[Conventional technology]

Conventionally, metal pipes used for extruding and transporting concrete and slurry, which are exposed to harsh environments such as corrosion and abrasion, have been coated with metal powder on their inner or outer surfaces in order to improve their characteristics and extend their service life. These methods include thermal spraying, plating, thermite, welding, and methods using an outer frame or core, but these methods have However, depending on the purpose and use, there are molding materials and dimensions that cannot be formed, and the disadvantage is that it is not versatile.

[Problem that the invention seeks to solve]

That is, in the prior art, (1) The thermal spraying method can be applied to the outer surface of the pipe, but it is difficult to apply the inner surface to small diameter objects of 50 nwn or less or to long objects (2) ) The plating method can form a metal layer on the inner and outer surfaces of the tube, but there is only a small amount of metal that can form the metal layer and it is difficult to apply a thick layer.

(3) The thermite method requires a wide range of combinations of reactive metals, and is still in the realm of research. (4) The weld overlay method is difficult to apply to long objects with small diameters on both the inner and outer surfaces, and is difficult to apply. The effect on the material is large, and the work requires skill, and in order to obtain an even product, it is necessary to rely on skilled workers or automation.Furthermore, since welding produces overlapped parts, Unfavorable characteristics of the film (5) In the method of forming the film using an outer frame or core, the metal powder that is to form the film is completely melted.

The above-mentioned frame, etc. must be used until it adheres, and it is difficult to remove the frame, etc. after the melting process. Especially when the outer frame and core are made of a metal layer, the molten metal powder may In the same way as the base material, it spreads, joins, and adheres to the frame, etc., so it is extremely difficult to remove it, and there are problems such as it may have a negative effect on the quality of the product. be.

[Means for solving problems]

In order to solve the above-mentioned problems of the conventional technology, the present invention has been developed to produce metal pipes on both the inner and outer surfaces according to various uses and purposes using simple equipment, in a short period of time and while maintaining a good environment. This was developed with the aim of providing a method for manufacturing a pipe with metal lining on the inner and outer surfaces that can easily form a metal lining layer. In the method for manufacturing an inner and outer metal lined tube having a lining layer, a metal powder suitable for the purpose and use is sprayed on the inner and outer surfaces of the metal tube.

After forming a metal powder layer in advance by a method such as sintering or adhesion, the metal tube is subjected to a centrifugal force of 2G or more on the inner surface.

While rotating the metal tube so that the centrifugal force on the outer surface is 7G or less, the entire metal tube is rotated at once or a portion thereof is continuously rotated.

A metal lining is formed on the inner and outer surfaces of the metal tube by heating the metal powder from the inside, the outside, or both the inside and outside to a temperature higher than the melting temperature of the metal powder to melt, diffuse, and adhere the metal powder layer on the inner and outer surfaces of the metal tube. It is characterized by forming.

[For production]

That is, in the present invention, a metal powder layer with high adhesion is formed in advance on the outer surface of a metal tube by thermal spraying or the like, and the metal powder is applied to the inner surface in a desired range at once or continuously.

The amount required to form a thick film is supplied, a metal powder layer is formed by centrifugal force, etc., and then the metal tube is heated to melt and diffuse the metal powder layer.

A metal lining layer is formed on the inner and outer surfaces of the metal tube by adhering the metal powder layer, and the method for forming the metal powder layer is not limited to the above method, but may include a method of attaching a metal powder sheet of a predetermined thickness to the inner and outer surfaces, For the inner surface, it is also possible to adopt a method in which pre-sintered metal powder is charged into the inside of the metal tube.

Also, when heating a metal tube, the centrifugal force on its inner surface is 2
While applying rotation to the metal tube such that the centrifugal force on the outer surface is 7 G or more, the desired metal powder is applied to the entire metal tube at once or a portion thereof continuously from the inside or outside or from both the inside and outside. By heating the metal powder to a temperature of 100 to melt, diffuse, and adhere the metal powder layer on the inner and outer surfaces of the metal tube, it is possible to form a metal lining layer that is nearly pore-free.

In addition, in the method of the present invention, if the centrifugal force on the inner surface is 2G or less, there is a risk that the formed metal lining layer will have a large number of pores, which may adversely affect the quality; When this happens, the molten metal powder scatters, making lining impossible.

Next, an example of an embodiment of the method of the present invention will be explained with reference to the drawings.

In FIG. 1, 1 is a metal tube on which a metal lining layer is to be formed on the inner and outer surfaces, 2 is a thermal spray gun for spraying metal powder 3 onto the outer surface of the metal tube 1, and 4 is a metal powder 3 that is sprayed by the thermal spray gun 2. 5 is a metal powder supply pipe for supplying metal powder 6 to the inner surface of metal pipe 1; 7 is a metal powder supply pipe for supplying metal powder 6 from metal powder supply pipe 5; is supplied to the inside of the metal tube 1, and the metal tube 1 is
a metal powder layer formed on the inner surface of the metal tube 1, 8 a heating device consisting of a high frequency inductor that heats the raw tube from the outside of the metal tube 1;
0 is a metal lining layer formed on the outside and inside of the metal tube 1 by melting the metal powder layers 4 and 7 by the heating device 8;
Reference numeral 11 denotes a rotating device for imparting rotation to the metal tube 1, and 12 denotes a tube support member of the rotating device 11.

The metal tube 1 is supported by the tube support member 12, the thermal spray gun 2 and the heating device 8 are placed outside the metal tube 1, and the metal powder supply tube 5 is inserted into the metal tube 1 and rotated once. Equipment
Driving Ii11, the centrifugal force on the inner surface of metal tube 1 is 2G.
As described above, the metal powder 3 is sprayed from the thermal spray gun 2 to form the metal powder layer 4 on the outer surface of the metal tube 1 while rotating so that the centrifugal force on the outer surface is 7 G or less, and the metal powder supply tube 5
A metal powder layer 7 is formed on the inner surface of the metal tube 1 by centrifugal force by feeding the metal powder 6 into the metal tube 1 , and while the heating device 8 is moved from the outside of the metal tube 1 , the metal powder layers 4 and 7 are heated. A metal lining 19.10 is formed on the outer and inner surfaces of the metal tube 1 by heating the metal powder to a desired heating temperature higher than their melting temperature to melt, diffuse, and adhere the metal powder. In order to perform this continuously, the thermal spray gun 2, the heating device 8, and the metal powder supply pipe 5 may be moved inside and outside the metal tube 1 at a constant speed while maintaining a constant interval.

Although the method for supplying the metal powder 6 through the metal powder supply pipe 5 described above was continuous, the metal powder 6 is supplied in advance while the metal pipe 1 is rotated, and the metal powder 6 is supplied by the centrifugal force. A metal powder layer 7 may be formed on the inner surface of the tube 1.

In addition, during the above heating, the heating atmosphere is oxidized.

If it is necessary to set it to either reduction or inertness, atmospheric gas 14 is supplied from the gas nozzle 13 to the inside of the metal tube 1.

Further, in the above example, high-frequency induction heating is used as the heating means to heat the metal tube 1 from the outside, but gas or other means may be used as the heating means, or the metal tube 1 may be heated from the outside. Heating may be performed from the inside or both the inside and outside.

〔Example〕

Next, specific examples of the method of the present invention will be described.

Example 1 (1) Metal pipe Steel pipe material 345C Dimensions Outer diameter 280rm, inner diameter 250rm, length 2500mm
rrrn (2) Metal powder type MSFNi5 (Ni-based self-fluxing alloy) Usage amount Outer surface 35 kg, inner surface 35 kg (3) Rotation speed 17 Orpm (4) Heating method Outer surface induction heating with high frequency inductor Heating conditions Frequency 1.0KIIz Feeding speed 2.2 mm/sac Input power: 300 KV (5) Atmosphere control gas used: Ar Flow rate: 25 Q/min When metal powder lining was applied under the above conditions, a metal lining layer of 2 mm thick was formed on the inner and outer surfaces of the steel pipe. was formed. Although high-frequency induction heating was used as the heating method, heating methods using other gases or the like may be used.

In addition, when lining was carried out by changing the centrifugal force and tube diameter using the above method, the results are shown in Table 1, and the rotation speed and diameter applicable range of the metal tube are shown in the chart in Figure 2. It was as shown.

Table 1 [Effects of the Invention] The present invention is as described above, and a metal lining layer is easily formed by simultaneously melting, diffusing, and adhering metal powder to the inner and outer surfaces of the metal tube while rotating the metal tube. Since this is a method, it can be applied to an extremely wide range of metal linings by selecting the most suitable metal powder according to the purpose and use.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of an embodiment of the present invention, and FIG. 2 is a chart showing the relationship between the diameter of a metal tube and the rotation speed.

Claims (1)

[Scope of Claims] 1. A method for producing an inner and outer metal lining tube having metal lining layers having characteristics different from those of the base material on the inner and outer surfaces of the metal tube, wherein the inner and outer surfaces of the metal tube are coated with a metal suitable for the purpose and use. After forming a metal powder layer in advance by a method such as thermal spraying, sintering, or adhesion, the metal tube is rotated so that the centrifugal force on the inner surface is 2 G or more and the centrifugal force on the outer surface is 7 G or less. Melting the metal powder layer on the inner and outer surfaces of the metal tube by heating the entire metal tube at once or in part continuously from the inside, the outside, or both the inside and outside to a temperature higher than the melting temperature of the metal powder, A method for producing an inner and outer metal lined tube, comprising forming a metal lining layer on the inner and outer surfaces of the metal tube by diffusion and adhesion. 2. A patent claim that forms a metal powder layer on the outer surface of a rotating metal tube by thermal spraying, etc., while supplying metal powder all at once or continuously to the inner surface of the tube to form a metal powder layer by centrifugal force. The method described in item 1 of the scope. 3. The method according to claim 1, wherein a metal powder layer is formed by attaching metal powder sheets of a predetermined thickness to the inner and outer surfaces of a metal tube. 4. The method according to claim 1, wherein a metal powder layer is formed by charging pre-sintered metal powder into a metal tube. 5. While rotating the metal tube, forming a metal powder layer on its outer surface by thermal spraying, etc., while supplying metal powder all at once or continuously to the inner surface to form a metal powder layer by centrifugal force, 2. The method according to claim 1, wherein the metal tube is continuously heated by a moving heating device.