Electrode for electrolytic grinding device

Abstract

To provide an electrode for an electrolytic polishing device, which enables efficient removal of burnt parts and formation of a passivation film even in places where it is difficult to adhere the electrode to curved surfaces or the like. [Solution] An electrode (11) for an electrolytic polishing apparatus used in an electrolytic polishing apparatus in which an electrode and a welded stainless steel product are placed relative to each other, and an electric short-circuit prevention material with water retention properties that covers the electrode and an electrolyte layer are interposed between the two to electrolyze, thereby removing weld burns and cleaning the stainless steel through electrochemical action. The electrode (11) is characterized in that it comprises an electrode core (20) made of flexible or elastic conductive carbon fiber material or metal member, either alone or in combination, and an electric short-circuit prevention material (30) that is flexible and has water retention properties and covers the electrode core (20) so that it is not exposed, the electric short-circuit prevention material (30) and the electrode core (20) are arranged to form an alternately stacked state, and the electric short-circuit prevention material (30) has a diaphragm-forming effect.

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 and 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 and toxic substance, conducted research and developed an electrolytic method for removing weld burns that uses a safe and harmless solution of neutral salt as the electrolyte, and obtained Patent No. 1543867 under the name "Method for descaling alloy steel." The applicant also developed an electrolytic device that enables safer and more harmless removal of weld burns, reducing the use of the previously used dangerous and toxic nitric hydrofluoric acid.

[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 removal work very effectively, but has the drawback of dissolving highly toxic hexavalent chromium during electrolysis. Therefore, this type of electrolyte has been improved to develop a revolutionary and safe electrolyte that does not dissolve hexavalent chromium even when electrolysis is performed using a commercially available simple direct current power supply, and this has attracted the attention of the industry.

[0004] Furthermore, the company has 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 that are commercially available and pose a risk due to the elution of hexavalent chromium, and has 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 voltage 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 detoxifying harmful hexavalent chromium dissolved during electrolysis.

[0006] The applicant has also made 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, and has established a method for cleaning and passivating the surface of stainless steel that forms a strong passive film 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, rust, oil, dirt, and other foreign matter adhering to the stainless steel surface without impairing the inherent corrosion resistance of stainless steel, and even improving it, and has obtained Patent No. 3484525 under the title ``Method for cleaning and passivating a stainless steel surface.''

[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 elucidated, and a fluorine-containing or fluorine-oxygen-based coating layer was formed on the surface or vicinity of the stainless steel by electrochemical means, by diffusing and penetrating hydrofluoric acid or hydrofluoric acid and oxygen in an ionic state, and the effect brought about by the formation of a new film having superior corrosion resistance compared to the oxygen-based passive film formed on the surface of conventional stainless steel, dramatically improved the inherent corrosion resistance of the stainless steel according to its type, and invented a stainless steel and a manufacturing method thereof which significantly improved various problems, particularly those specific to austenitic stainless steel, ranging from pitting corrosion caused by chloride to abnormal corrosion and even stress corrosion cracking.

[0008] Generally, the role of the electrode portion, which forms the core of the electrolytic treatment device as described above, is to cover a conductive material such as stainless steel with a water-retentive substance made of woven or nonwoven fabric of natural or synthetic fibers as a diaphragm, and to carry out 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 respond to all welding conditions and to achieve sufficient performance in removing weld burns, and have therefore traditionally been applied to the generally smooth surrounding areas of welds.

[0009] The applicant has obtained Patent No. 5849348 under the title "Electrode for electrolytic polishing equipment" as an electrode suitable for all welding conditions. As shown in Fig. 7, this electrode is made by covering a stainless steel plate 51 with a cloth bag 53 to prevent electrical short circuits, and installing conductive carbon fiber or stainless steel fiber 55 inside 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 elastic, making it a freely deformable electrode, and has been well received by many users. However, because a stainless steel flat plate is used for the core of the electrode, the flexibility of the cloth bag containing the carbon fiber or stainless steel fiber is limited, and only a part of the electrode adheres to the curved surface, so it takes time to completely remove the weld burn.

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

[0013] The present invention relates to a method for manufacturing a semiconductor device using electrodes arranged in a relative position. Electrolytic treatment objectA water-retentive electrical short-circuit prevention material and an electrolyte layer are interposed between the electrodes, and a current is passed between the electrodes to electrolyze the electrodes by electrochemical action. The object to be electrolytically treated An electrode for an electrolytic polishing device used in an electrolytic polishing device for removing welding burns and cleaning stainless steel, comprising an electrode core made of a conductive carbon fiber material or a metal member having flexibility or elasticity, either alone or in combination, and a flexible, water-retentive electrical short-circuit prevention material that covers the electrode core so that it is not exposed. It is a flat electrode formed by combining , The flat electrode has flexibility so that it can be freely deformed to fit the shape of the object to be electrolytically treated. Prevention of electrical short circuits Material The electrode for electrolytic polishing apparatus is characterized in that a diaphragm-forming effect is imparted to the

[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 electrolytic polishing apparatus according to the present invention, The flat electrode has its upper and lower surfaces sewn together or threaded. It is characterized by:

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

[0017] The electrode for electrolytic polishing apparatus according to the present invention can efficiently remove weld burns from stainless steel welded products, which was not possible with conventional electrodes, without leaving any residue, and can also form a passive film on the weld burned parts, improving their corrosion resistance, making it extremely beneficial to industry. [Brief description of the drawings]

[0018] [Figure 1] 1A to 1C are diagrams for explaining the configuration and method of use of an electrolytic polishing apparatus 1 including an electrode 11 for an electrolytic polishing apparatus according to the present invention. [Diagram 2] FIG. 1 is a diagram for explaining the configuration of an electrode 11 for an electrolytic polishing apparatus according to a first embodiment of the present invention. [Diagram 3] FIG. 2 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. [Figure 4] FIG. 4 is a diagram for explaining the configuration of an electrode 12 for an electrolytic polishing apparatus according to a second embodiment of the present invention. [Diagram 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 electrolytic polishing apparatus electrode 50 shown in FIG. [Figure 6] This is an example in which a treatment for removing weld burn 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 that illustrates a schematic configuration of a conventional electrode 50 for an electrolytic polishing apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 an 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 portion 201 of the welded workpiece 200, electricity begins to flow, and the weld burn is removed by an 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 for explaining 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 plate-shaped 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 flow.

[0024] The electrode core 20 is a conductive carbon fiber 21 or a conductive metal member 22 having flexibility and elasticity. A 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 may use 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 covering material made of a bag-shaped non-conductive woven fabric that covers the electrode core 20, and one end of the material is fixed to a metal terminal 35 for current passage while covering the electrode core 20 as shown in Fig. 2. The fixing method of the electrical short-circuit prevention material 30 is not particularly limited 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, has water retention properties, and is 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 is a thin rectangular parallelepiped, in other words, a flat plate, and has flexibility and elasticity. By making the electrode 11 flat as in this embodiment, the characteristics of the electrode 11 can be utilized and it can be deformed as shown in FIG.

[0028] When the electrode 11 is used, if there is concern that the electrode core 20 may move inside the electrode 11 and become biased, 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 them. This is the same for 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, in which the current-carrying metal terminal 35 is omitted.

[0030] In Fig. 3(A), the electrode 11 is used in a flat plate shape. In this example, the tip portion 15 of the electrode 11 is pressed against the stainless steel welded product 200. In Fig. 3(B), the tip portion 15 of the electrode 11 is bent toward the base end portion 16. In Fig. 3(C), the electrode 11 is curved into a cylindrical shape. In Fig. 3(D), the electrode 11 is rolled up like a snail shell and deformed into a tapered cone shape. The base end portion 16 is on the side of the metal terminal 35 for current supply. After the electrode 11 is deformed as shown in Figs. 3(B) to (D), it can be tied with thread or string or sewn to maintain the deformed shape.

[0031] Fig. 4 is a diagram for explaining the configuration of an electrolytic polishing apparatus electrode 12 according to a second embodiment of the present invention, 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 denoted by the same reference numerals, and description thereof will be omitted.

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

[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. Thus, 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 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 of the present invention has an electrode core covered 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 the finish and corrosion resistance.

[0035] In addition, the electrode for electrolytic polishing apparatus according to the present invention has flexibility and elasticity, so it conforms to the shape of the welded workpiece and adheres closely to it, and the burn removal speed is further improved. Furthermore, the electrode for electrolytic polishing apparatus according to 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 parts, gaps, etc.

[0036] The electrode for electrolytic polishing apparatus according to the present invention is not limited to the above embodiment, and may be modified within the scope of the present invention. The electrode for electrolytic polishing apparatus according to the present invention is not particularly limited in external shape and dimensions, as long as the electrode core is covered with an electrical short-circuit prevention material having non-conductivity, water retention, and flexibility. In the above embodiment, a cylindrical or flat electrode is shown, but the external shape of the electrode may be a rectangular column, spindle, or flat shape, and an electrode suitable for the shape of the weld burnt part of the welded product may be used.

[0037] In addition, the electrode for electrolytic polishing apparatus 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. Also, if a metal member that undergoes plastic deformation and retains its shape after deformation is used for the electrode core and it is used by deforming it to fit the curved surface shape of the welded workpiece, the entire surface of the electrode will be in close contact, improving efficiency. EXAMPLES

[0038] Comparative Example Fig. 5 shows a comparative example in which a welded curved surface was treated using an electrolytic polishing device 1 equipped with a conventional electrode 50 for an electrolytic polishing device. It can be seen that some of the weld burn remains. 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 Fig. 6 shows an example in which a welded curved surface was treated using an electrolytic polishing device 1 equipped with an electrode 11 for an electrolytic polishing device according to the first embodiment of the present invention. It can be seen that the weld burn was completely removed. Specifically, the remaining weld line portion, indicated by the arrow in Fig. 6, appears as a slightly black line, but the black line is thinner than that in Fig. 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 equal to that of the conventional electrodes for electrolytic polishing apparatus in straight sections and approximately twice as fast in curved sections. [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 from curved surfaces, but it can also improve corrosion resistance. [Explanation of symbols]

[0043] 1 Electropolishing equipment 2 Power supply 3 Electrode Grip Cord 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 side 32 Bottom surface 35 Metal terminal for current carrying 50 Conventional electrodes 51 Stainless steel plate of conventional electrode 53 Cloth bag used for conventional electrodes 55 Stainless steel fibers used in conventional electrodes 100 electrolyte container 101 Electrolyte 200 Welded products 201 Weld burnt area

Claims

1. An electrode for an electrolytic polishing device used in an electrolytic polishing device that performs weld burn removal and cleaning of stainless steel, which is an object of electrolytic treatment, by electrochemical action by passing current between the electrodes and the object of electrolytic treatment, with a water-retentive electrical short-circuit prevention material and an electrolytic solution layer interposed between the electrodes and the object of electrolytic treatment, A flat electrode formed by combining an electrode core made of a conductive carbon fiber material or a metal member having flexibility or elasticity, either alone or in combination, with an electrical short-circuit prevention material having flexibility and water retention that covers the electrode core so as not to expose it, The flat electrode has flexibility allowing it to be freely deformed to match the shape of the object to be electrolytically treated, and the electrical short-circuit prevention material is provided with a diaphragm-forming effect.

2. The electrode for an electrolytic polishing apparatus according to claim 1, characterized in that 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. An electrode for an electrolytic polishing apparatus as described in claim 1 or 2, characterized in that the flat electrode has its upper and lower surfaces sewn together or treated with a thread passing through it.

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