JPH0336523Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an apparatus for rapidly removing an annular oxide film formed when a cylindrical metal material is heat treated in air.

(Prior Art) When pipes made of metal materials such as stainless steel are welded in air, an annular oxide film is formed along the weld line, and sulfuric acid or hydrochloric acid is mainly used for descaling. Now, instead of immersing pipes in sulfuric or hydrochloric acid solutions, a jelly containing a hydrochloric acid solution is applied over the pipe's oxide coating and washed off with water after about 30 minutes. In some cases, paint containing silver powder is applied along the annular oxide film to conceal the oxide film. As for the acid method,
Cathodic electrolysis, anodic electrolysis in a 5-20% solution of sulfuric acid,
There is a device that performs PR electrolysis.

(Problem to be solved by the invention) When a jelly-like substance containing a hydrochloric acid solution is used, a pollution problem arises in the treatment of wastewater because the water used for washing has an odor and corrodes other substances. Although the removal effect of this jelly-like material increases when it is heated, there remains the problem that it is necessary to leave it on the oxide film for a long time, resulting in poor working efficiency. Furthermore, coating paint containing silver powder is expensive, and the paint tends to peel off during use. Although the electrolytic method can quickly remove even a strong oxide film, the oxide film on the recesses dissolves more slowly than on the protrusions, and the problem of wastewater treatment still remains.

The present invention was proposed in order to improve the above-mentioned problems regarding the removal of cyclic oxide films. Even cyclic oxide films can be removed quickly and easily, and the problem of waste liquid treatment is avoided. The purpose is to provide a removal device that generates almost no generation.

(Means for Solving the Problems) In order to achieve the above object, the cyclic oxide film removal device 2 according to the present invention includes a liquid-absorbing member that contacts a metal material, and a support member that receives the liquid-absorbing member. and,
and the other electrode body that contacts the surface of the metal material. This liquid-absorbing material is preferably a band-shaped felt, sponge, etc., which can sufficiently absorb and retain the dilute acid treatment liquid and has abrasion resistance. On the other hand, it is preferable that at least a portion of this support member constitutes one electrode body, and the portions of both electrode bodies are made of an insoluble electrode material such as sintered carbon. This support member is generally a receiving plate 4 (see FIG. 1) with an arcuate side surface.
The used dilute acid treatment liquid discharged from the support member is circulated to a tank 10 by a pump 8. In order to apply a predetermined potential between both electrode bodies using the external power supply 12 and generate locally high current density, at least a part of the support member is an anode or a cathode electrode body, and the other electrode body is made of metal. Although contact is made with the material surface, electrolysis using the PR method is also possible.
Keep the voltage low to avoid generating too much gas such as SO ₂ at the anode electrode. The liquid-absorbing member is impregnated with a dilute acid treatment solution whose main component is sulfuric acid or hydrochloric acid, and is usually impregnated with a dilute acid treatment solution that can be easily post-treated, brought into contact with the oxide film, and diluted as desired. An inhibitor or the like may be added to the acid treatment solution. The liquid-absorbing member or the metal material rotates relatively along the oxide film, and a chuck 14 (see FIG. 1) or a plurality of rotors 16 (see FIG. 3) is used for this rotation. Metal materials that can be processed include various types of steel such as stainless steel, aluminum, zinc and its alloys. Further, the oxide film that can be treated can be removed not only in an annular shape on the surface of a cylindrical body, cylinder, or sphere such as a pipe, but also in a circular shape on the flat surface of a metal material. For various steels such as stainless steel, aluminum, and stainless steel materials, after separating the oxide film on the surface caused by welding etc., nickel plating may be applied to the activated separated part.

(Function) In the device 2 of the present invention, the oxide film 18 (Fig. 2) on the surface of the metal material is rubbed with a liquid-absorbing member impregnated with a dilute acid treatment liquid while locally electrolyzing at a high current density. The oxide film is quickly separated and removed. Regarding the metal materials to be treated, cathode electrolysis causes less corrosion of metal materials, maintains dimensional accuracy, and is good for plating adhesion because it is activated. Not suitable for steel or spring steel. On the other hand, in anodic electrolysis, the oxide film is physically removed using oxygen gas, and the surface of the metal material becomes passivated, preventing corrosion and mitigating the occurrence of hydrogen embrittlement. Not suitable for zinc and its alloys.

(Example) To explain the present invention based on the drawings, in the removal device 2 shown in FIG.
4, and the rotation mechanism may be a headstock of a lathe or the like. The pipe 20 is, for example, a welded pipe shown in FIG. 2, and an annular oxide film 18 is formed on the surface of the pipe along the weld line. A receiving plate 4 having an arcuate side surface concentric with the pipe is installed below the pipe 20, and supports a liquid-absorbing member such as a band-shaped felt material 24 on the receiving plate. The receiving plate 4 has an inverted U-shaped cross section as shown in FIG. contact the surface. A liquid sending pipe 26 is communicated with the lower end of the receiving plate 4 and extends to the drop tank 10 via the circulation pump 8. The tank 10 sends the dilute acid treatment liquid to the nozzle 30 via the liquid sending pipe 28. From an appropriate external DC power source 12, the nozzle 3
0 and the right end of the receiving plate 4, the right end of the receiving plate contacts one electrode body and the surface of the pipe 20, and the nozzle tip corresponds to the other electrolyte. In FIG. 1, the nozzle tip is an anode electrode body, but this tip may be a cathode electrode body, or a PR current may be used.

When this device 2 is operated, a localized high current density is generated at the right end of the felt material 24 between the right end of the receiving plate and the pipe surface. On the other hand, nozzle 3
When the dilute acid treatment liquid is injected from zero, the treatment liquid flows on the pipe surface and is absorbed by the felt material 24, so that the felt material is constantly impregnated with the dilute acid treatment liquid. Since the felt material 24 is always in contact with the surface of the pipe 20, when the pipe is rotated by the chuck 14, the felt material 24 rubs the oxide film 18 on the pipe surface, causing the oxide film 18 to move along the circumference. Then, they are separated one by one. The used dilute acid treatment liquid is sent from the receiving plate 4 to the tank 10 by the pump 8 and circulated, and only a small amount of new liquid is replenished, so that almost no waste liquid is generated.

Regarding this device 2, the other two electrode bodies are separated from the nozzle 30, and the electrode body 31 (first
(see the dashed line in the figure), or the electrode body may be a suitable rotor (not shown).

In the apparatus 50 shown in FIG. 3, a large wheel 52 having an annular oxide film to be removed is
It is supported and rotated by four rollers 16.
A receiving plate 54 having an arc-shaped side surface concentric with the wheel is installed below the wheel 52, and a band-shaped felt material 56 is supported by the receiving plate. The receiving plate 54 has an inverted U-shaped cross section, and both ends of the receiving plate 54 can be bent slightly upward to hold a small amount of the dilute acid treatment liquid. A pipe 58 is connected to the receiving plate 54, and the dilute acid treatment liquid supplied from the pipe is sent to one electrode body of the receiving plate 54, and the excess dilute acid treatment liquid coming out from the felt material 56 is transferred to the receiving plate. Hold at 54. The other two electrode bodies 60 are placed close to the right end of the receiving plate 54, and are positioned upward and in contact with the wheel surface.

(Effect of the invention) The device of the invention quickly and easily removes the oxide film from the surface of the metal material by rubbing the surface of the oxide film on the metal material with a liquid-absorbing member while locally electrolyzing at a high current density. The work efficiency is superior to that of conventional equipment, and there is almost no deterioration of the working environment. In the device of the present invention, since friction is performed by the liquid-absorbing member, it hardly occurs that the oxide film on the recessed portions dissolves more slowly than on the convex portions.
In addition, since the device of the present invention generally uses only a small amount of dilute acid treatment liquid, it produces less waste liquid than an electrolysis device that installs an electrolytic bath, and this dilute acid treatment liquid has less odor and is free from other substances. It does not corrode water, and there is little risk of pollution problems related to wastewater treatment.

[Brief explanation of drawings]

Fig. 1 is an overall explanatory diagram schematically showing the device according to the present invention, Fig. 2 is a perspective view of a welded pipe having an annular oxide film, and Fig. 3 is another modification used for large-sized metal materials. An explanatory diagram showing an example, Figure 4 is the first
FIG. 3 is a partial cross-sectional view showing the main part of the figure. 2...removal device, 4...receiving plate, 6...roller, 8...circulation pump, 10...drop tank, 12...external DC power supply, 14...chuck, 16...rotor, 18...oxide film, 20...pipe, 24... Felt material, 30
…nozzle.

Claims (1)

[Claims for Utility Model Registration] 1. A device for removing an annular oxide film produced when a cylindrical metal material is heat-treated in air, which removes the oxide film by surface contact with the metal material. A liquid-absorbing member with an arc-shaped side surface to be scraped, an upwardly facing receiving plate that holds the liquid-absorbing member and constitutes at least a portion of one electrode body, and is connected to the lower end of the receiving plate and extends to the tank. and the other electrode body that contacts the surface of the metal material,
Using an external power source, a predetermined potential is applied between both electrode bodies to generate a locally high current density, and the liquid-absorbing member is impregnated with a dilute acid treatment solution, and the used dilute acid discharged from the receiving plate is A cyclic oxide film removal device that circulates the treatment liquid into a tank using a pump. 2. Device according to claim 1, characterized in that the receiving plate has a U-shaped cross section.