JPH0421832Y2 - - Google Patents

Description

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

(Prior art) When pipes made of metal materials such as stainless steel are welded in the air, a ring-shaped oxide film is formed along the weld line, and this oxide film is strong and cannot be easily exposed to a concentrated acid or alkaline treatment solution. It cannot be removed by soaking alone. Conventionally, instead of immersing this pipe in an acid or alkaline treatment solution, a jelly-like substance containing an acid treatment solution was applied onto the oxide film of the pipe, and the treatment was carried out for about 30 minutes.
Rinse with water after a minute. In some cases, paint containing silver powder is applied along the annular oxide film to conceal the oxide film.

(Problem to be solved by the invention) When a jelly-like substance containing an acid treatment liquid is used, pollution problems may occur in the treatment of wastewater because the rinse water has an odor and corrodes other substances. many. Although this jelly-like material increases its effectiveness in removing oxides when heated, the problem remains that it is necessary to leave it on the oxide film for a long time, resulting in poor working efficiency. Furthermore, applying paint containing silver powder is expensive, and the paint tends to peel off during use.

The present invention was proposed in order to improve the above-mentioned problems regarding the removal of metal oxide films, and even metal oxide films can be removed quickly and easily, and there are almost no problems with waste liquid treatment. The purpose is to provide a removal device that does not.

(Means for Solving the Problems) In order to achieve the above object, the metal oxide film removal device 2 according to the present invention includes an electrolytic bath 4 containing a relatively dilute acid or alkaline treatment liquid 3, and A counter electrode 6 having a rectangular flat horizontal part 30 and a U-shaped vertical part 32 arranged around the inside of the tank, and a clip 20 for vertically suspending a cylindrical material to be treated 8 to be immersed in an acid or alkaline treatment liquid. The other electrode body 10 is connected to the tank, and an ultrasonic oscillation mechanism consisting of a vibrator 12 and an oscillator is installed at a lower position in the tank. Ultrasonic waves have a high frequency and travel in a straight line, making it difficult for them to reach recessed or shadowed parts of the material 8 to be treated. Therefore, it is preferable that the vibrator 12 of the ultrasonic oscillation mechanism is installed below the electrolytic bath 4. The counter electrode body 6 can be set as either a cathode or a cathode, but it is generally preferable to set it as a cathode in order to perform anode removal.
The used dilute acid or alkali treatment liquid 3 discharged from the electrolytic cell 4 may be filtered by a pump (not shown) and then circulated to the electrolytic cell 4, or a new solution may be pumped into the electrolytic cell. You can forcibly add it and then discard it. The cylindrical material 8 to be processed is made of various types of steel such as stainless steel, copper and its alloys, and the like. For copper and steel materials, after separating the oxide film on the surface caused by welding, etc., nickel plating is sometimes applied to the activated separated parts.

(Function) The removing device 2 of the present invention removes a strong oxide film that is generated when a metal material is heat-treated in the air by electrolysis and ultrasonic waves, and the acid or alkaline treatment liquid used is The thickness is determined so that it can be disposed of as is. For example, in anodic electrolysis, the cylindrical material to be treated 8
The oxide film is physically removed by the oxygen gas generated on the surface of the oxide film, and chemical and physical effects such as saponification and dispersion of the dilute acid or alkaline treatment liquid 3 are added to this.
Although hydrogen embrittlement does not occur and there is no electrodeposition of impure metals, care must be taken to avoid corrosion or pitting on the pipe surface. Furthermore, in the apparatus 2 of the present invention, the oxide film is destroyed by the ultrasonic shock wave, and the processing liquid 3 is agitated by the sound pressure caused by the reflection of the ultrasonic waves, with partial agitation by cavitation. Further, when the treatment liquid 3 is alkaline, oxide removal and degreasing treatment can be performed simultaneously.

(Example) To explain the present invention based on the drawings, in the removal apparatus 2 shown in FIG. Connect to 10,
It may be suspended in the dilute acid or alkaline treatment liquid 3 in the electrolytic cell 4. The cylindrical material 8 to be treated is, for example, a welded pipe 22 as shown in FIG. 2, and an annular oxide film 2 is formed on the surface of the pipe along the weld line.
4 is occurring. The electrolytic cell 4 is generally a hollow rectangular shape with an open top, and a ferrite vibrator 12 is installed in the lower part of the electrolytic cell, and these are lined with a stainless steel plate 26 . The ultrasonic vibration mechanism includes a vibrator 12 and an oscillator (not shown) connected to the vibrator.
These may be installed together or separately.
The electrolytic cell 4 is generally constructed of a lined steel plate 26 to prevent stray current from flowing due to electrical leakage during electrolysis. As is clear from FIG. 3, the counter electrode body 6, which is a cathode, has a rectangular horizontal part 30 close to the inner circumference of the inner container 28 and a U-shaped vertical part 32 in contact with the bottom wall of the inner container 28. By having
Achieve uniform oxide removal by electrolysis. If the material 8 to be treated is about the size of a small pipe 22 on which an annular oxide film 24 is formed, the vertical portion 3 of the counter electrode 6
2 may not be provided. Although not shown, a drain pipe is connected to the lower part of the inner container 28 and extends to a drop tank via a circulation pump, and after filtering the drain liquid in the tank, it is sent together with new liquid to an electrolytic tank via a liquid sending pipe. The processing liquid may be returned to step 4.

A direct current of 30 A at 30 V, for example, is passed through this device 2, and the oxide film 24 is physically peeled off using oxygen gas generated on the surface of the material to be treated, such as the pipe 22, by electrolysis, and then treated with dilute acid or alkali. Chemical and physical actions such as saponification and dispersion of the liquid 3 are added, and the oxide film 24 is destroyed by ultrasonic shock waves, and partial stirring is caused by cavitation, and the process is performed using sound pressure caused by the reflection of ultrasonic waves. Liquid 3 is also stirred. As a result, the oxide film 24 on the pipe surface
However, stainless steel welding often leaves an oxide film on the inner circumference of the pipe. In this case, the oxide film 2 on the pipe surface
After removing the counter electrode 4, a rod-shaped counter electrode 34 as shown in FIG. 4 is used in place of the counter electrode 6. The pipe 22 connected to the electrode body of the anode is suspended vertically in the treatment liquid 3, and the counter electrode body 3 is placed in the center of the pipe.
If 4 is inserted vertically, it is possible to also remove the oxide film on the inner circumference of the pipe. Since ultrasonic waves have a straight propagation property, it is preferable to suspend the ultrasonic waves vertically because a uniform removal effect can be achieved. This pipe may be attached to a conveyor for continuous movement through the electrolytic cell 4.

(Effects of the invention) The device of this invention uses electrolysis and ultrasonic waves to quickly remove the strong oxide film that occurs when metal materials are heat-treated in the air, and is much more efficient than conventional devices. Excellent. In addition, in the device of the present invention, the acid or alkaline treatment liquid used has a dilute concentration and is lower in concentration than the waste liquid generated from conventional electrolyzers, so this treatment liquid has little odor and does not corrode other substances. No pollution problem will occur even if the liquid is disposed of as is when draining. Since the wastewater generated by the device of the present invention can be disposed of as is, there is no need to dilute it with water to a predetermined concentration, and there is no risk of violating regulations on the total amount of wastewater. Further, when the treatment liquid is alkaline, removal of strong oxides and degreasing treatment can be performed at the same time, making it possible to shorten the surface treatment time.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view schematically showing a removal 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 a counter electrode used in the present invention in a plastic inner container. FIG. 4 is a side view showing a separate counter electrode used in the present invention. 2... Removal device, 3... Dilute acid or alkaline treatment liquid, 4... Electrolytic cell, 6... Counter electrode, 8... Material to be treated, 10... Electrode body, 12... Vibrator, 34
...A rod-shaped opposite pole.

Claims (1)

[Claims for Utility Model Registration] 1. An electrolytic cell containing a relatively dilute acid or alkaline treatment solution, and a counter electrode having a rectangular plane horizontal part and a U-shaped vertical part disposed around the inside of the electrolytic cell. , the other electrode body is connected to a cylindrical material to be treated that is immersed in an acid or alkaline treatment liquid and suspended vertically, and an ultrasonic oscillation mechanism consisting of a vibrator and an oscillator is installed at a lower position in the bath. In preparation, the oxide film produced when metal materials are heat-treated in air using electrolysis and ultrasonic waves is removed,
A device for removing metal oxide film at a concentration that allows treated wastewater to be disposed of as is. 2. When removing the oxide film on the inner periphery of a cylinder, a rod-shaped counter electrode is used instead of the counter electrode described above, and this is placed vertically in the center of a vertically suspended cylindrical material to be treated. Item 1. Removal device according to item 1.