JPS6263680A - Treatment of inside of tubular metallic material - Google Patents

Abstract

PURPOSE:To make a flux for etching unnecessary and to simply plate the inside of a long-sized tubular material by heating the material under reduced pressure to vaporize a metal for coating placed on part of the inside of the material and to deposit the resulting vapor on the inside of the material. CONSTITUTION:A metal for coating is placed on part of the inside of a tubular metallic material and the material is heated in vacuum or under reduced pressure. The metal for coating is vaporized by the heating and the resulting vapor is deposited on the inside of the material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for treating the inner surface of a metal pipe material with a different metal, such as water and sewage water and hot water.

) fη Can be applied as an inner surface treatment method for pipe materials such as supply pipes for liquids such as water and oil, supply pipes for gas bodies such as fuel gas, heat transfer pipes that utilize heat transfer inside and outside the pipe, pressure transfer pipes, etc. .

[Prior art and its problems] The following methods are known as conventional methods for treating the inner surface of metal pipe materials, but each method has its own drawbacks.

(1) Electroplating method When treating the inner surface of a pipe material by electroplating, it is necessary to install an anode on the plated surface. It was also necessary to maintain a constant distance between the plated surface and the anode to ensure uniform plating thickness, and to prevent short circuits between the two electrodes. For this reason, in order to plate the inner surface of a small-diameter pipe material or a long material, ViJM is required for supplying the plating solution and holding the electrode.

(2. Electroless plating method) Unlike the electroplating method, the electroless plating method does not require an anode and is applicable to small-diameter pipes. However, when the moisture content of the reducing agent and metal ions in the plating solution decreases, The deposition rate decreases.The lifetime of the metal solution is unsuitable for processing large amounts of material in a relatively short period of time.Also, the metals to which electroless plating can be applied depend on the ability of the reducing agent and the plating metal. Base metals could not be applied due to limitations related to the reduction potential of

A common drawback of electroplating and electroless plating is that if pre-treatment and post-treatment are not carried out sufficiently, the treated surface will be uneven and poor adhesion will occur. The biggest drawback is that many of the plating solutions contain poisonous and deleterious substances, and the wastewater treatment equipment must be adequately maintained.

(a. Hot-dip plating method There are two methods for hot-dip plating inside a pipe: immersing it in a metal melting tank, and heating and rotating the pipe material after inserting plated metal into the inner surface of the pipe. These methods prevent corrosion. This method has drawbacks such as requiring a specific flux and being difficult to apply to long materials and coil materials.

[Object of the Invention] An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide an inner surface treatment method that can be applied to long pipe materials.

[Summary of the Invention] The present invention provides coating metal on a part of the inner surface of a metal pipe material, and heats the pipe material in a vacuum or reduced pressure environment to evaporate the coating metal. The purpose is to attach it to the surface.

Some metals have a high vapor pressure below the melting point of many metal materials. For example, the temperature of the metal that has a vapor pressure of 1 ImRH (J) is 487°C for Zn.

Mq: 621°C, C: d: 394°C, Se: 356°C, etc., and by placing other metals in these vapors, the metal vapors adhere to the surface of the metal, and some of them are absorbed into the base metal. diffuses into and alloys.

In addition to the metals mentioned above, metals that can be used include AS.

! -1g, Rb, Te, etc., and alloys containing these as main components can also be used.

Generally, in vacuum evaporation, the degree of vacuum is set to about 10 Torr, and the temperature of the base metal is much lower than that of the evaporation source.However, in the present invention, the evaporation source and the base metal are kept at the same temperature, so that even long materials can be uniformly coated. The coating conditions are such that coating can be performed even at a vacuum degree of about 10'2 torr, making it suitable for industrial production.

For metal pipe materials, AI! , AIJ, CLJ, Fe,
Mn, Ni, pb, pt, "ri, Cr, Co, Pd
.

Mo, Nb, Tc, Ru, Rh, Zr, Y, Hf.

One or more of Ta, W, Re, Os, and Ir can be used as the main component, but the inner surface is
Even if it is smooth, it may have grooves or protrusions parallel to the longitudinal direction of the pipe or spirally, or discontinuous irregularities.

[Embodiments of the invention] Example 1 Outer diameter 15.9m! Grooves with a depth of 0.1M and a width of 0.3M were machined in the longitudinal direction of the pipe at a pitch of 0.6m on the inner surface of a coiled copper pipe with a wall thickness of 0.7a* and a length of 400m. A mixture of 80 parts by weight of 200 mesh Mq powder and 20 parts by weight of glycerin and shaped into the base 1 was adhered to the groove.

This steel pipe was heated at 750° C. for 11 hours in a vacuum annealing device under reduced pressure to 104 torr.

A Cu-Mg alloy containing a maximum of 5% of Mg 11 degrees was formed to a thickness of 5 μm on the entire surface inside the steel pipe.

Example 2 Outer diameter 18.0FM4. 150 meshes of Znn powder 8 x yeast was attached to both ends of a straight steel pipe with a wall thickness of 1.6 mm and a length of 10 m, and a f.
: Heated at 600°C for 30 minutes in an environment of 10'2 torr.

A 3 μm thick 7N coating layer was formed on the entire inner and outer surfaces of the steel pipe.

Example 3 Cocoon outer diameter 15.9. Zn powder was placed inside one end of a coiled steel tube with a wall thickness of 0.7 m and a length of 400 m, and the coiled steel tube was heated at 600° C. for 1 hour while exhausting air from the other end. As a result, the Zn vapor evaporated at one end of the coil flowed toward the other end, which was evacuated, and Zn adhered to the interior of the copper tube sequentially from one end, making it possible to obtain a Zn-coated steel tube on the inner surface.

The metal for coating may be installed by placing the metal in a small open container and feeding it into the pipe, or by feeding it into the pipe as a wire. In this case, the shape of the coating metal installed on the inner surface of the tube is in the form of a single particle of powder.

Foil-like. It is not particularly limited to liquid form.

In addition, in Example 3, when vapor deposition is performed while exhausting air from one end, the coating metal does not have to be placed inside the tube at the narrow end, but if the evaporated metal vapor is introduced into the tube, it can be placed outside the tube. Good too. For example, it is also possible to use an introduction pipe such as a trumpet pipe at the other end to introduce metal vapor into that part.

If an alloy layer like that in Example 1 is desired for the inner surface of the tube material, a heat diffusion treatment may be performed at the same time as the coating treatment or after the coating treatment to alloy the tube material and the coating metal.

[Effects of the Invention] Since the present invention is a method of heating in a vacuum or reduced pressure environment to evaporate the coating metal and attach it to the inner surface of the pipe material, simple cleaning is sufficient for pretreatment, and poisons and chemicals are removed. Because it does not require the use of , it has high integrity and can be easily applied to long parts. Furthermore, with the method of the present invention, it is possible to treat Mg, AJ, 1'G, etc., which cannot be wet-plated.

Claims (1)

[Claims] (1) A coating metal is installed on a part of the inner surface of a metal pipe material, and the coating metal is evaporated and attached to the inner surface of the pipe material by heating the pipe material in a vacuum or reduced pressure environment. Features a method for treating the inner surface of metal pipe materials.