JPS60190568A - Treatment of inside surface of metallic pipe material - Google Patents

Abstract

PURPOSE:To coat easily and uniformly different metals on the inside surface of a long- sized pipe material by coating a mixture composed of the granular compd. material of a metal having the m.p. lower than the m.p. of a metallic pipe material and a liquid material on the inside surface of said metallic pipe material and heating the pipe material to a uniform temp. to evaporate the liquid material. CONSTITUTION:A mixture composed of a granular material of a compd. such as the oxide, sulfide, chloride, etc. of a metal having the m.p. lower than the m.p. of a metallic pipe material and a liquid material which evaporates or decomposes and gasifies at the m.p. of said granular material is coated on the inside surface of the metallic pipe material. The pipe material coated with said mixture on the inside surface is heated to the temp. above the m.p. of the above-mentioned low melting metal and below the m.p. of the pipe material to coat the inside surface of the metallic pipe material with the metal. If the above-mentioned metallic pipe material is Cu, Al, Ti, Mg, steel, stainless steel or an alloy consisting essentially of one kind thereof, the granular material of the metallic compd. contg. >=50% components contg. >=1 kinds among Sn, Pb, Zn, Ni, Al, Ag, Au and Cu is preferable. The heating treatment is performed preferably in a reducing atmosphere and further the above-mentioned liquid material which exhibits a reducing property at the heat treating temp. is preferably used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Background and Objects of the Invention] The present invention relates to a treatment method for coating the inner surfaces of various metal pipe materials with dissimilar metals.

Conventional methods for coating the inner surface of pipe materials include the following methods, but each method has the following drawbacks.

(1) Method using extrusion method This method is a method in which the inner layer and the outer layer are mixed in advance, and the inner layer and outer layer are made into a composite pipe (-layered pipe) whose inner surface is coated with different metals by extrusion molding using composite extrusion bits 1 to 1. It is. In this method, the manufacturing process includes a composite billet manufacturing process, an extrusion process,
Furthermore, there are many drawing processes and processes to reduce the diameter to the specified dimensions, making it difficult to manufacture.
This puts you at a disadvantage in terms of strikes. Furthermore, if the metal covering the inner surface is a low melting point metal, it may melt due to the heat of deformation during extrusion molding, making it impossible to obtain a normal composite tube. Furthermore, if there is a large difference in deformation resistance between the tube base material and the covering material during extrusion, there are drawbacks such as difficulty in normal extrusion and pultrusion.

(2) Inner surface plating method This method can be considered to cover the inner surface of the tube with electroplating of 71gJ by pouring a plating solution of the metal to be coated on the inner surface of the tube, but it is difficult to coat the inner surface of the tube with electroplating. Control of liquid concentration, current density, etc. becomes complicated, making it unsuitable for industrial production.

(3) Welded pipe method This method seam-welds the pipe material and the sheathing material into a tubular shape with the sheathing material side inward. Welding may cause sifting, and the coating metal may be exposed on the outer surface of the tube at the seam weld, or conversely, the surface of the tube may be exposed on the inner surface of the tube, making it impossible to obtain a uniform coating layer on the inner surface of the tube. There are drawbacks.

An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a treatment method with excellent industrial productivity that uniformly coats the inner surface of a long tube with a dissimilar metal.

[Summary of the Invention] In order to achieve the above object, the following measures were adopted in the present invention.

That is, a step of applying a mixture of a metal compound powder having a lower melting point than the pipe material and a liquid substance that vaporizes or decomposes and gasifies at the melting point of the powder onto the inner surface of the pipe material;
A method was adopted which included the step of heating the tube material coated on the inner surface at a temperature in the range above the melting point of the low melting point metal and below the melting point of the tube material.

When considering Cu, AI, Ti, Mg, alloys containing one of these as a main component, steel, stainless steel, etc. as metal tube materials, the metals that are practically effective as coating metals are S.
Limited to n, Pb, Zn, AI, Ni, Ag, Au, and Cu. Moreover, if the total content of one or more of these components is 50% or more, the inner surface coating effect will be exhibited in practice. Therefore, as the compound of the low melting point metal in the present invention, granules of oxides, sulfides, and chlorides of the metals and alloys containing them as main components are used.

The liquid substance that vaporizes or decomposes and gasifies at the melting point of the powder and granules is preferably a reducing liquid, such as isopropyl alcohol, but is not limited to this, and does not adversely affect the reduction of the powder or granules. It may be something that has no effect. Therefore, the heating atmosphere may be air, but a reducing atmosphere using a Go, 1-(2, Ni-(3) decomposition gas tank is preferable.) The second limit of the heating temperature is theoretically below the melting point of the pipe material. Although any temperature is acceptable, it is practically desirable that the temperature is about 50° C. lower than the melting point of the tube material.

When heat-treated under the conditions described above, a wide coating of reduced and molten metal is formed, and a diffusion layer is partially formed. In order to promote diffusion, it is effective to add a separate heating step.

[Embodiment 1 of the invention Specific examples of the present invention are shown below.

Example 1 In order to coat the inner surface of a steel pipe with an outer diameter of 9.52 mm and a wall thickness of 0.41111111, Sn oxide powder (SnO) was applied.
A paste obtained by mixing 50% isovyl alcohol and 50% SnO was applied almost uniformly to the inner surface of the copper tube, and then heated at 500'C for 5 minutes. As a result, SnO on the inner surface of the copper tube is reduced and the molten WAS
n, and a steel pipe with a uniform 3n coating layer was obtained after cooling.

Example 2 In order to coat the inner surface of a steel pipe with an outer diameter of 22 mm and a wall thickness of 1.5 mm with Zn, Zn oxide powder (ZnO) was mixed with 50% isopropyl alcohol and 50% ZnO to form a paste. was applied to the inner surface of the steel pipe, and then the steel pipe was heated at 600° C. for 5 minutes. the result,
ZnO was reduced and became molten Zn, and after cooling, a uniform Zn swamp was formed on the inner surface of the tube.

Example 3 Z on the inner surface of a steel pipe with an outer diameter of 15.88 mm and a wall thickness of Q and 7 mm.
In order to coat n, Zn oxide powder (ZnO) is mixed at 50% with the drawing oil used for drawing and stretching pipes using dies and plugs to form a paste, and this mixture is used as a lubricant to form the steel pipe with an outer diameter of 12.7a+i. By reducing the diameter to a wall thickness Q of 5 mm, a wide film made of a mixture of ZnO and drawing oil was formed on the inner surface of the copper tube.

Afterwards, this steel pipe was placed in a reducing gas containing 2% CO2.
Heated at 00°C for 20 minutes. 1° As a result, a uniform Zn'Ml coating and a CLJ-1n alloy layer were formed on the inner surface of the copper tube.

Effects of the Invention" 2. As is clear from the above description, the present invention has advantages such as being able to be manufactured in a corrugated manner and being easy to process long objects.

4゜Writing procedural amendments) Coo, G., 05 IIBW Year Month Mouth Name of the invention Name of the invention Person who amended the method for treating the inner surface of metal pipe materials Relationship to the case Applicant Address 2-1 Marunouchi, Chiyoda-ku, Tokyo Number 2 name (!
112) LEE '5: L Electric Wire 4 Zhu Shiki Company Representative Ministry Mizukami Tokugobe Representative 〒io.

``Detailed Description of the Invention'' column of Specification 1 to be amended. - Insert the following sentence between page 5, line 15 and line 16 of the statement of contents of the amendment.

1. By using the technology of the present invention, it is possible to improve the corrosion resistance of the inner surface of the pipe material and improve the strength of the pipe material. Flood for gas bodies such as fuel gas (can be applied as a method for treating the inner surface of pipes H such as supply pipes or heat transfer pipes and pressure transfer pipes that utilize heat transfer inside and outside the pipe.)

Claims (4)

[Claims] (1) A method of coating the inner surface of a metal pipe material with a metal having a lower melting point than the pipe material, in which a compound powder or granule of the metal is mixed with a liquid substance that vaporizes or decomposes and gasifies at the melting point of the powder or granule. A method for treating the inner surface of a metal tube material, comprising the steps of: coating the inner surface of the tube material; and heating the inner surface coated tube material at a temperature above the melting point of the low melting point metal and below the melting point of the tube material. (2) Metal tube material is Cu, AI, T 15Mg, steel,
It is stainless steel or an alloy whose main component is one of these, and the powder of the metal compound is 3N. One of Pb, Zn, Ni, AI, AQ, Au, Cu
2. The method according to item 1, wherein the total content of the species or components containing two or more species is 50% or more. (3) The method according to item 1 or 2, wherein the metal tube material is heat-treated in a reducing atmosphere. (4) Item 1 above, wherein the liquid substance mixed with the metal compound powder exhibits reducing properties at the heat treatment temperature;
The method described in paragraph 2 or 3.