• Title/Summary/Keyword: electrolytic polishing

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Development of Ultral Clean Machining Technology with Electrolytic Polishing Process

  • Lee, Eun-Sang;Park, Jeong--Woo;Moon, Young-Hun
    • International Journal of Precision Engineering and Manufacturing
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    • v.2 no.1
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    • pp.18-25
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    • 2001
  • Electrolytic polishing is the anodic dissolution process in the transpassive state. It removes non-metallic inclusion and improves mechanical and corrosion resistance of stainless steel. If there is a Bailby layer, it will be removed and the true structure of the surface will be restored. Electrolytic polishing is normally used to remove a very thin layer of material from the surface of metal object. A new electrolyte composed of phosphoric, sulfuric and distilled water has been developed in this study. Two current density, high & low current density regions, have been applied in this study. In this study, In the region of high current density, there is no plateau region but excellent electrolytic polishing effect can be accomplished in short machining time because material removel process and leveling process occur simultaneously. In the low current density region, there can be found plateau region. The material removal process and leveling process occur successively. The aim of this work is to determine electrolytic polishing for stainless steel in terms of high & low current density and workpiece surface roughness.

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Development of The Magnetic -Electrolytic-Abrasive Polishing (MEAP) (1st) -Effect of magnetic field on electrolytic finishing process- (자기전해복합경면가공의 개발에 관한 연구(제 1보) -전해공정에 미치는 자기장의 영향-)

  • 김정두
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.4 no.3
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    • pp.25-30
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    • 1995
  • A new finishing process, magnetic-electrolytic-abrasive polishing(MEAP), combining Lorentz' force effect in the traditional electrolytic finishing process was developed to realize the high efficiency as well as high surface quality of finishing . The paper describes the theoretical basis about the modification of electrolytic ions motion by the magnetic field. The effect of magnetic field on the electrolytic process was discussed was and analyzed from the result of model test.

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A Study on the Ultra-precision Machining of National Standard Electrode by the Magnetic-Electrolytic-Abrasive Polishing System (자기전해 가공시스템에 의한 국가 표준원기의 초정밀 표면 가공에 관한연구)

  • 김정두
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1996.03a
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    • pp.137-142
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    • 1996
  • Magnetic-electrolytic-abrasive polishing system(MEAPS) was developed for machining national standard electrode and its finishing characteristics was analyzed. The paper describes the operational principle of MEAP system by experimental results. The finishing characteristics and optimal finishing condition for national standard electrodes were experimented and analyzed. As a result, MEAPS can improve straightness as well as surface roughness.

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Study on Electrochemical Polishing for Stainless Steel using Micro Pulse Current (미세 펄스전원을 이용한 스테인레스강의 전기화학연마)

  • 이동활;박정우;문영훈
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.127-130
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    • 2003
  • Electrolytic polishing is the anodic dissolution process in the transpassive state. It removes non-metallic inclusions and improves mechanical and corrosion resistance of stainless steel. Electrolytic polishing is normally used to remove a very thin layer of material from the surface of a metal object. An electrolyte of phosphoric, sulfuric and distilled water has been used in this study. In the low current density region, there can be found plateau region and material removal process and leveling process occur successively. In this study, an electrochemical polishing process using pulse current is adopted as a new electrochemical polishing process. In electrochemical machining processes, it has been found that pulse electrochemical processes provide an attractive alternative to the electrochemical processes using continuous current. Hence, this study will discuss the electrochemical polishing processes in low current density region and pulse electrochemical polishing.

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Study on Electrochemical Polishing for Stainless Steel 300 Series using Micro Pulse Current (미세 펄스전원을 이용한 스테인레스강 300 계열의 전기화학연마)

  • 이동활;박정우;문영훈
    • Transactions of Materials Processing
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    • v.12 no.4
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    • pp.388-393
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    • 2003
  • Electrolytic polishing is the anodic dissolution process in the transpassive state. It removes non-metallic inclusions and improves mechanical and corrosion resistance of stainless steel. Electrolytic polishing is normally used to remove a very thin layer of material from the surface of a metal object. An electrolyte of phosphoric acid 50% in vol., sulfuric acid 20% in vol. and distilled water 30% in vol. has been used in this study. In the low current density region, there can be found plateau region and material removal process and leveling process occur successively. In this study, an electrochemical polishing process using pulse current is adopted as a new electrochemical polishing process. In electrochemical machining processes, it has been found that pulse electrochemical processes provide an attractive alternative to the electrochemical processes using continuous current. Hence, this study will discuss the electrochemical polishing processes in low current density region and pulse electrochemical polishing.

Development of Magneto-Electrolytic-Abrasive Polishing System for Piston Pin (피스톤 핀의 자기전해 경면연마 시스템 개발)

  • 김정두
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1998.03a
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    • pp.59-64
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    • 1998
  • We need to achieve th mass product through methods of higher efficient, higher precise manufacturing process than those of existing precision abrasive machining. Thus, this study is to develop mirror-like surface machining technique of outer diameter of the piston pin by the compound magneto-electrolytic abrasive polishing system. The procedure of machining is followed as first, fulfill the pre-processing by cylindrical grinder, second, complete mirror-like surface by the method of magneto-electrolytic abrasive polishing used CBN non-woven abrasive pads. In this study, it was found that the best suitable conditions of mirror-like surface polishing were that the electrode density was 0.1A/$\textrm{cm}^2$, the applied pressure 1.5kgf/$\textrm{cm}^2$, the feed rate 0.5mm/rev, and the rotoation velocity of workpiece 80rpm, and that the surface roughness was reduced in this conditions.

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A study on the Surface Improvement of Fine-Micro Needles Applying Electrochemical Polishing (전해연마를 적용한 미세 마이크로 니들의 표면 향상에 대한 연구)

  • Jung, Sung-Taek;Kim, Hyun-Jeong;Wi, Eun-Chan;Kong, Jung-Shik;Baek, Seung-Yub
    • Design & Manufacturing
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    • v.13 no.3
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    • pp.48-52
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    • 2019
  • As the consumer market in the mold, automation and aerospace industries grows, the demand for chemical machining using on electrochemical polishing increases. To enhance the surface roughness and gloss of the micro-needle, we have studied for an electrochemical polishing. Electrochemical polishing requires the chemical reaction of solution and material according to the electrolyte and electrode. In this study, sulfuric acid(30%), phosphoric acid(50%), and DI-water(20%)were used as the electrolytic solution, and the electrolytic solution temperature used $58^{\circ}C$. Electrochemical polishing was carried out in experimental conditions, and the micro-needle experiment was carried out from the basic experiment to obtain the experimental conditions. Experimental results show that as the voltage and current increase, the surface roughness improved and the gloss is improved. So, the best result for this experiment was obtained in condition 6, which improved micro-needle.

Sample Preparation for Microstructural Characterization of Ni-Yttria-Stabilized Zirconia Anodes

  • Sim, Soo-Man
    • Journal of the Korean Ceramic Society
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    • v.55 no.4
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    • pp.376-380
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    • 2018
  • Microstructural characterization of Ni-yttria-stabilized zirconia (YSZ) anodes using secondary electron images has been limited by a lack of contrast between Ni and YSZ phases. This paper reports a sample preparation method for obtaining secondary electron images that allow the detection of Ni, YSZ, and pore phases together. Ni-YSZ anode samples were obtained by reducing NiO-YSZ samples prepared by using the mixed oxide method. Colloidal silica polishing and electrolytic etching were performed on the Ni-YSZ samples. The morphological change of the sample surface after each polishing process is examined.

Formation Behavior of Passive State Film on Stainless Steel for Metallic Ion Concentration in Electropolishing Solution (전해 연마액 금속 이온 농도에 따른 스테인리스 스틸의 부동태 피막 형성 거동)

  • Oh, Jong Su;Kang, Eun-Young;Jeong, Dae-Yong
    • Korean Journal of Materials Research
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    • v.32 no.4
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    • pp.230-236
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    • 2022
  • The formation behavior of a passive state film on the surface of STS304 in electrolytic solution was analyzed to determine its metallic ion composition. The properties of passive state films vary depending on the Fe and Cr ions in the electrolytic solution. It was observed that the passive state film surface became flat and glossy as the concentration of Fe and Cr ions in the electrolytic solution increased. The corrosion resistance property of the passive state film was proportional to the amount of Fe and Cr in the electrolytic solution. An initial passive state film with high Fe concentration was formed on the surface of STS304 during early electrolytic polishing. Osmotic pressure of Fe ions occurs between the passive state film and electrolytic solution due to the Fe ion concentration gradient. The Fe in the passive state film is dissolved into the electrolyte, and Cr fills up the Fe ion vacancies. As a result, a good corrosion-resistant floating film was formed. The more Fe ions in the electrolytic solution, the faster the film is formed, and as a result, a flat passive state film containing a large amount of Cr can be formed.