Electrode for electrolytic polishing device

Abstract

To provide an electrode for an electrolytic polishing device capable of efficiently removing a burn and forming a passive film even in a case where the electrode is hardly adhered to a curved surface part or the like.SOLUTION: An electrode 11 for an electrolytic polishing device is used in an electrolytic polishing device in which, in a state where an electric short-circuit preventing material having water retentivity and covering an electrode and an electrolytic solution layer are interposed between the electrode and a welded product of stainless steel which are relatively disposed, electrolysis is performed by applying a current between the electrode and the welded product, and welding burn removal and cleaning of the stainless steel are performed by an electrochemical action. The electrode for the electrolytic polishing device includes an electrode core 20 in which a conductive carbon fiber material or a metal member, each having flexibility or elasticity, is used alone or mixed, and an electric short-circuit preventing material 30 which covers the electrode core 20 so as not to be exposed and has flexibility and water retentivity. The electric short-circuit preventing material 30 and the electrode core 20 are arranged so as to form an alternately laminated state, and a diaphragm forming effect is imparted to the electric short-circuit preventing material 30.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a novel electrode structure for dissolving and removing weld burns on stainless steel welded products by electrolysis, while simultaneously forming a passivation film with excellent corrosion resistance. [Background technology]

[0002] In the past, the applicant, in light of the fact that the work of removing weld burns after welding stainless steel relied on nitric hydrofluoric acid, which is an extremely dangerous poisonous substance, developed an electrolytic method of removing weld burns using a safe and harmless solution of neutral salt as the electrolyte, and obtained Patent No. 1543867 under the title of "Alloy Steel Descaling Method." He developed an electrolytic device that reduces the use of the previously dangerous poisonous nitric hydrofluoric acid and enables safer and more harmless weld burn removal.

[0003] The gist of this invention is a direct current electrolysis method in which a neutral salt solution of phosphoric acid, sulfuric acid, and hydrofluoric acid is mixed with glycerin to form an electrolyte, and the stainless steel to be treated is used as the anode. This method can perform the burn-off work very effectively, but has the drawback of eluting highly toxic hexavalent chromium during electrolysis. Therefore, this type of electrolyte has been improved, and a revolutionary and safe electrolyte has been developed that does not elute hexavalent chromium even when electrolysis is performed using a simple commercially available DC power supply, and this has attracted attention in the industry.

[0004] Furthermore, we have developed a revolutionary power supply for electrolytic processing that has been improved to completely prevent the elution of hexavalent chromium, even when using neutral salt electrolytes, which are currently available on the market and pose a risk due to the elution of hexavalent chromium, and have obtained Patent No. 1908719 under the title "Method for removing scale associated with welding of alloy steel."

[0005] The gist of this invention is that it uses a solution of inorganic neutral salt as an electrolyte and performs electrolysis with an AC-DC superimposed current, which is a DC current superimposed with an AC voltage whose amplitude is equal to or slightly higher than the DC voltage. This has the outstanding effect of immediately reducing and neutralizing harmful hexavalent chromium eluted during electrolysis.

[0006] The applicant has also established a method for cleaning and passivating the surface of stainless steel, which makes it possible to use alternating current, an electrochemical technique that was previously inapplicable because it destroys the known oxygen-based passive film on the surface of stainless steel. This allows a strong passive film to be formed on the surface of stainless steel while maintaining the beauty of the surface, thereby removing in a single step oxide films formed by welding or heat treatment, as well as various foreign substances such as rust, oil, and dirt that adhere to the surface of stainless steel without impairing the stainless steel's inherent corrosion resistance, and in fact improving it. This method has been granted Patent No. 3,484,525 under the title ``Method for cleaning and passivating the surface of stainless steel.''

[0007] Furthermore, in Patent No. 4,218,000, entitled "Stainless steel having a fluorine-containing or fluorine-oxygen-based coating layer formed thereon, and a manufacturing method thereof," the mechanism for forming a strong passive film, which was unclear in Patent No. 3,484,525, was clarified. By using an electrochemical method, hydrofluoric acid or hydrofluoric acid and oxygen are diffused and penetrated in ionic form on or near the surface of the stainless steel, a fluorine-containing or fluorine-oxygen-based coating layer is formed. The effect of forming a new coating that is more corrosion-resistant than the oxygen-based passive film formed on the surface of conventional stainless steel dramatically improves the inherent corrosion resistance of the stainless steel depending on the type of steel, and the inventors have invented a stainless steel and a manufacturing method thereof that significantly improves various problems, particularly those specific to austenitic stainless steel, from pitting corrosion due to chloride to abnormal corrosion and even stress corrosion cracking.

[0008] Generally, the role of the electrode, which forms the core of the electrolytic treatment equipment described above, is to coat a conductive material such as stainless steel with a water-retaining substance made of a woven or nonwoven fabric of natural or synthetic fibers as a diaphragm, and to perform electrolytic treatment by placing an electrolyte between the electrode and the stainless steel surface to be treated. However, conventional electrodes have a uniform structure in which a woven fabric is covered on a flat metal plate, making it difficult to adapt to all welding conditions and to achieve sufficient performance in removing weld burns, and have therefore generally been applied to the smooth periphery of welds.

[0009] The applicant has obtained Patent No. 5849348 for an electrode suitable for all welding situations, called an "electrode for electrolytic polishing equipment." As shown in Figure 7, this electrode consists of a stainless steel plate 51 covered with a cloth bag 53 to prevent electrical short circuits, and conductive carbon fiber or stainless steel fiber 55 attached to the entire inside of the cloth bag. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent No. 1543867 [Patent Document 2] Patent No. 1908719 [Patent Document 3] Patent No. 3484525 [Patent Document 4] Patent No. 4218000 [Patent Document 5] Patent No. 5849348 Summary of the Invention [Problem to be solved by the invention]

[0011] The electrode for electrolytic polishing equipment described in Patent No. 5849348 is flexible and resilient, making it a deformable electrode that has been well received by many users. However, because the electrode uses a stainless steel flat plate for its core, the flexibility of the cloth bag containing the carbon fiber or stainless steel fiber is limited, and only a portion of the electrode adheres to the curved surface, so it takes time to completely remove the weld burn.

[0012] An object of the present invention is to provide an electrode for an electrolytic polishing apparatus that can increase the contact surface with the curved surface to enable efficient burn removal and simultaneously form a passivation film on the weld burn removal removal portion. [Means for solving the problem]

[0013] The present invention provides an electrode for an electrolytic polishing apparatus used in an electrolytic polishing apparatus that performs weld burn removal and cleaning of stainless steel by electrochemical action by passing an electric current between an electrode and a welded stainless steel product arranged relative to each other, with an electric short-circuit prevention material with water retention that covers the electrode and an electrolyte layer interposed between the two. The electrode for an electrolytic polishing apparatus is characterized in that it comprises an electrode core made of a flexible or elastic conductive carbon fiber material or metal member, either alone or in combination, and an electric short-circuit prevention material that is flexible and has water retention and covers the electrode core so as not to be exposed, the electric short-circuit prevention material and the electrode core are arranged to form an alternately stacked state, and the electric short-circuit prevention material has a diaphragm-forming effect.

[0014] In the electrode for an electrolytic polishing apparatus according to the present invention, the electrode core is characterized in that it is formed in a single layer or multiple layers of a plurality of carbon fiber materials, a plurality of metal members, or a mixture of a plurality of the carbon fiber materials and the metal members.

[0015] In the electrode for an electrolytic polishing apparatus according to the present invention, the electrode for an electrolytic polishing apparatus has a flat plate shape and is flexible, and can be used in its flat plate shape or by bending, folding, curving, or deforming the shape into a rounded shape.

[0016] In the electrode for an electrolytic polishing apparatus according to the present invention, a flexible thin resin wire or resin tube may be used in combination with the electrode core to impart elasticity. [Effects of the Invention]

[0017] The electrode for electrolytic polishing apparatus according to the present invention can efficiently remove weld burns from welded stainless steel products without leaving any residue, which conventional electrodes were unable to do adequately, and can also form a passivation film on the weld burned areas, improving corrosion resistance, making it extremely beneficial to industry. [Brief explanation of the drawings]

[0018] [Figure 1]1A and 1B are diagrams illustrating the configuration and usage of an electrolytic polishing apparatus 1 including an electrode 11 for an electrolytic polishing apparatus according to the present invention. [Figure 2] 1 is a diagram illustrating the configuration of an electrode 11 for an electrolytic polishing apparatus according to a first embodiment of the present invention. [Figure 3] 1 is a schematic diagram showing a modified form of the electrode 11 for an electrolytic polishing apparatus according to the first embodiment of the present invention. FIG. [Figure 4] FIG. 4 is a diagram illustrating the configuration of an electrode 12 for an electrolytic polishing apparatus according to a second embodiment of the present invention. [Figure 5] This is a comparative example in which a welding burn removal process was carried out using an electrolytic polishing apparatus equipped with the conventional electrode 50 for an electrolytic polishing apparatus shown in FIG. [Figure 6] This is an example in which a welding burn removal process was carried out using an electrolytic polishing apparatus 1 equipped with an electrode 11 for an electrolytic polishing apparatus according to the present invention. [Figure 7] FIG. 1 is a cross-sectional view schematically showing the configuration of a conventional electrode 50 for an electrolytic polishing apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0019] 1 is a diagram illustrating the configuration and usage of an electrolytic polishing apparatus 1 including an electrode 11 for an electrolytic polishing apparatus according to a first embodiment of the present invention. The electrolytic polishing apparatus 1 has a power supply 2, an electrode grip cord 3 and an earth clip cord 5 connected to the power supply 2, and an electrode for an electrolytic polishing apparatus (hereinafter sometimes referred to as an electrode) 11. An electrode grip 4 is provided at the tip of the electrode grip cord 3, and the electrode 11 is attached to the electrode grip 4.

[0020] The electrolytic polishing apparatus 1 is used as follows: The clip 6 provided at the tip of the earth clip cord 5 is attached to the welded workpiece 200. The electrode 11 is impregnated with the electrolyte 101 poured into the electrolyte container 100 (see FIG. 1(B)), and when the electrode 11 is brought into contact with the weld burn 201 of the welded workpiece 200, electricity begins to flow, and the weld burn is removed by electrochemical action.

[0021] The electrolytic polishing apparatus 1 has the same configuration as a conventional electrolytic polishing apparatus except for the electrode 11, and is not particularly limited. The method of using the electrolytic polishing apparatus 1 is also not particularly limited. On the other hand, the configuration and structure of the electrode 11 are specified as described below.

[0022] Fig. 2 is a diagram illustrating the configuration of an electrolytic polishing apparatus electrode 11 according to a first embodiment of the present invention, in which Fig. 2(A) is an external view of the electrolytic polishing apparatus electrode 11 and Fig. 2(B) is a cross-sectional view of the electrolytic polishing apparatus electrode 11. While Fig. 1 shows a substantially cylindrical electrode 11, Fig. 2 shows a flat electrode 11.

[0023] The electrode 11 of this embodiment includes a conductive electrode core 20, a non-conductive electrical short-circuit prevention material 30 that covers the electrode core 20, and a metal terminal 35 for current supply.

[0024] The electrode core 20 is made of flexible and elastic conductive carbon fiber 21 or conductive metal member 22. Known carbon fiber can be used as the carbon fiber 21. A conductive thin wire or the like can be used as the metal member 22. The electrode core 20 may use the carbon fiber 21 or the metal member 22 alone, or a mixture of the carbon fiber 21 and the metal member 22.

[0025] The electrical short-circuit prevention material 30 of this embodiment is a bag-shaped covering material made of non-conductive woven fabric that covers the electrode core 20, and as shown in Fig. 2, one end of the material is fixed to the current-carrying metal terminal 35 while covering the electrode core 20. There are no particular restrictions on the fixing method of the electrical short-circuit prevention material 30 as long as it can cover the electrode core 20. The electrical short-circuit prevention material 30 can be made of a material that is non-conductive, water-retentive, and flexible, and a resin non-woven fabric can be used instead of a woven fabric.

[0026] The current-carrying metal terminal 35 is configured so as to be fixable to the electrode grip 4. The current-carrying metal terminal 35 is used by being firmly fixed to the electrode grip 4 using a bolt or the like.

[0027] The electrode 11 of this embodiment has a thin rectangular parallelepiped shape, in other words, a flat plate shape, and is flexible and elastic. By making the electrode 11 flat as in this embodiment, the characteristics of the electrode 11 can be utilized and it can be deformed and used as shown in Figure 3.

[0028] If there is a concern that the electrode core 20 may move inside the electrode 11 during use and cause deviation, the upper surface 31 and the lower surface 32 of the electrical short-circuit prevention material 30 may be sewn together at an appropriate interval or threaded across. This also applies to the electrode 12 for an electrolytic polishing apparatus of the second embodiment.

[0029] FIG. 3 is a diagram for explaining a modified form of the electrode 11 shown in FIG. 2, and the current-carrying metal terminal 35 is not shown.

[0030] In Figure 3(A), the electrode 11 is used in its flat form. This is an example in which the tip portion 15 of the electrode 11 is pressed against the stainless steel welded workpiece 200. Figure 3(B) is an example in which the tip portion 15 of the electrode 11 is bent toward the base end 16. Figure 3(C) is an example in which the electrode 11 is curved into a cylindrical shape. Figure 3(D) is an example in which the electrode 11 is rolled up like a snail shell and deformed into a tapered cone shape. The base end 16 is on the side of the current-carrying metal terminal 35. After the electrode 11 has been deformed as shown in Figures 3(B) to 3(D), it can be tied with thread or string or sewn up to maintain the deformed shape.

[0031] Fig. 4 is a diagram illustrating the configuration of an electrolytic polishing apparatus electrode 12 according to a second embodiment of the present invention, in which Fig. 4(A) is an external view of the electrolytic polishing apparatus electrode 12 and Fig. 4(B) is a cross-sectional view of the electrolytic polishing apparatus electrode 12. In the electrolytic polishing apparatus electrode 12 according to the second embodiment of the present invention, the same components as those in the electrolytic polishing apparatus electrode 11 according to the first embodiment of the present invention shown in Fig. 2 are designated by the same reference numerals, and description thereof will be omitted.

[0032] While the electrode 11 of the first embodiment of the present invention is a single layer, the electrode 12 of the second embodiment has a multi-layer structure. The electrode 12 of the second embodiment is formed by stacking three electrodes 11 having the same structure as the electrode 11 of the first embodiment of the present invention, and is fixed to one current-carrying metal terminal 35.

[0033] The three electrodes 11 constituting the electrode 12 of the second embodiment are connected at their base ends 16 via a metal terminal 35 for current flow, but are not connected at any portion other than the base ends 16. Therefore, when in use, the three electrodes 11 can be spread apart so that their tip ends 15 are spaced apart. In this embodiment, the electrode 12 has a three-layer structure, but it may also have a multi-layer structure of two or four or more layers.

[0034] As explained above using the electrodes for electrolytic polishing apparatus of the first and second embodiments, the electrode for electrolytic polishing apparatus according to the present invention has an electrode core coated with an electrical short-circuit prevention material that acts as a diaphragm when current is applied, thereby preventing sparks due to contact between the electrode and the welded workpiece, suppressing wear of the electrode core, and improving finish quality and corrosion resistance.

[0035] Furthermore, the electrolytic polishing device electrode of the present invention has flexibility and elasticity, so it conforms to the shape of the welded workpiece and adheres closely to it, thereby significantly improving the burn removal speed.Furthermore, the electrolytic polishing device electrode of the present invention can be made into various external shapes, so it can also be used to remove weld burns on curved surfaces, box corners, narrow areas, gaps, etc.

[0036] The electrode for an electrolytic polishing apparatus according to the present invention is not limited to the above-described embodiment and can be modified within the scope of the present invention. The electrode for an electrolytic polishing apparatus according to the present invention is not particularly limited in its external shape or dimensions, as long as the electrode core is coated with an electrically non-conductive, water-retentive, and flexible material that prevents electrical short circuits. While the above-described embodiments show cylindrical and flat electrodes, the external shape of the electrode may be prismatic, spindle-shaped, or flat, and an electrode suitable for the shape of the weld burnt portion of the welded product may be used.

[0037] Furthermore, the electrode for electrolytic polishing equipment according to the present invention, which has a resin tube or a resin thin wire or rod added to the electrode core, can be set to a flexibility suitable for the work, improving workability. Furthermore, if a metal member that can be plastically deformed and retains its shape after deformation is used for the electrode core and it is deformed to fit the curved surface of the welded workpiece, the entire surface of the electrode will be in close contact, improving efficiency. [Example]

[0038] Comparative Example Fig. 5 shows a comparative example in which a welded curved surface was treated using an electrolytic polishing apparatus 1 equipped with a conventional electrode 50 for an electrolytic polishing apparatus. It can be seen that some weld burns remain. Specifically, the weld line indicated by the arrow in Fig. 5 appears as a black line, but the black line appears thick.

[0039] Example 1 Figure 6 shows an example in which a welded curved surface was treated using an electrolytic polishing apparatus 1 equipped with an electrode 11 for an electrolytic polishing apparatus according to the first embodiment of the present invention. It can be seen that the weld burn was completely removed. Specifically, the remnants of the weld line, indicated by the arrow in Figure 6, appear as slightly black lines, but the black lines are thinner than those in Figure 5.

[0040] [Table 1]

[0041] As shown in Table 1, the electrodes for electrolytic polishing apparatus according to the present invention had a weld burn-off speed that was approximately the same in straight sections and approximately twice as fast in curved sections as the conventional electrodes for electrolytic polishing apparatus. [Industrial Applicability]

[0042] It can be used to remove weld burns from stainless steel welded products, and not only can it improve the speed and finish of removing burns, especially on curved surfaces, but it can also improve corrosion resistance. [Explanation of symbols]

[0043] 1 Electropolishing equipment 2 Power supply 3 Electrode Grip Cords 4 Electrode Grip 5 Earth Clip Cord 6 clips 11,12 Electrodes for electropolishing equipment, electrodes 15 Electrode tip 16 Electrode base end 20 Electrode Core 21 Carbon Fiber 22 Metal Fibers 30 Electrical short circuit prevention material 31 Top surface 32 Bottom surface 35 Metal terminal for current carrying 50 Conventional electrodes 51 Conventional electrode stainless steel plate 53 Cloth bag used in conventional electrodes 55 Stainless steel fibers used in conventional electrodes 100 electrolyte container 101 Electrolyte 200 Welded Products 201 Weld burn area

Claims

1. An electrode for an electrolytic polishing device used in an electrolytic polishing device that electrolyzes a stainless steel welded workpiece by passing current between the electrode and the workpiece, with a water-retentive electrical short-circuit prevention material and an electrolytic solution layer interposed between the electrode and the workpiece, and removes welding burns and cleans the stainless steel by electrochemical action. An electrode core made of a flexible or elastic conductive carbon fiber material or a metal material, either alone or in combination; a flexible and water-retentive electrical short-circuit prevention material that covers the electrode core so that it is not exposed; Equipped with An electrode for an electrolytic polishing apparatus, characterized in that the electrical short-circuit preventive agent and the electrode core are arranged to form an alternately stacked state, and the electrical short-circuit preventive agent is given a diaphragm-forming effect.

2. 2. The electrode for an electrolytic polishing apparatus according to claim 1, wherein the electrode core is formed in a single layer or multiple layers of a plurality of the carbon fiber materials, a plurality of the metal members, or a mixture of a plurality of the carbon fiber materials and the metal members.

3. The electrode for the electrolytic polishing apparatus according to claim 1 or 2, characterized in that the electrode for the electrolytic polishing apparatus has a flat shape and is flexible, and can be used in its flat shape or by bending, folding, curving, or deforming the shape into a rounded shape.

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