• Title/Summary/Keyword: 철부식

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Wire netting processing technology with abrasion and corrosiveness by using Beam energy (빔 에너지를 이용한 내 마모 및 내 부식성을 갖는 철망 가공 기술)

  • Jung, Sung-Chan;Sun, Kyung-Chul;Shin, Young-Sik;Choi, Jeong-Sik;Cha,, In-Su
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1029_1030
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    • 2009
  • 본 논문에서는 빔 에너지를 이용하여 내 마모 및 내 부식성을 갖는 철망을 가공하여, 빔 에너지 조사 전과 후의 SEM 사진과 인장강도를 측정하여 비교, 분석 하였다. 전자빔으로 표면을 개질하기 전보다 후의 표면이 더 치밀해짐을 SEM사진을 통하여 볼 수 있었고, 인장강도를 측정 하여 개질 전과 후를 비교 하였는데, 인장강도와 관련된 탄성계수가 더 크게 나타나 전자빔 조사에 의한 샘플이 긴 수명을 갖는 요인이 분석되었다.

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The Characteristic Analysis of breaking failure on ACSR-OC Conductor (알루미늄 절연전선의 단선고장 특성 분석)

  • Kim, Dong-Myung;Ra, Dong-Chae
    • Proceedings of the KIEE Conference
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    • 2008.04b
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    • pp.185-187
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    • 2008
  • ACSR-OC 전선은 알루미늄, 아연 및 철 등 세 가지 금속이 서로 접촉되는 이질구조이므로 도체 내에 전해질의 수용액이 존재할 경우 전해부식이 일어나기 쉽고 표면이 손상되었을 경우는 서지의 고정점으로 작용하여 단선될 우려가 있다. Al 절연전선이 염분에 의해 발생되는 변화를 살펴보았다. 시료는 10년이상 현장에서 사용한 후 천거한 전선과 신품에 대해 기계적 강도시험(KSC 3113의 5.4.3 (인장하중시험)), 소선의 성분분석(SEM) 및 현미경 관찰을 실시하였다. 실험결과, 철거전선 표면에서는 알루미늄 외 산소, 염소(Cl), 나트륨(Na) 등이 관찰되었으며 소선은 부식 또는 진행 중이어서 전선의 인장력이 저하되어 있었다. 또 표면이 손상된 전선에 대해 파괴시험, 현미경 관찰 등을 실시하여 절연에 미치는 영항을 조사하였다.

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Study on the Crevice Corrosion Behavior of SS 400 in Marine Environment (해양환경중에서 SS400강재의 간극부식거동에 관한 연구)

  • 임우조;정기철;안석환;윤병두
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2000.11a
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    • pp.1-6
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    • 2000
  • This paper was studied on the crevice corrosion behavior of SS 400 in marine environment. In 0%, 2%, 3.5%, 5% NaCl solution, the aspect of the crevice corrosion and polarization behavior under the crevice corrosion was investigated. And Weight loss rate of SS 400 with crevice and non-crevice was measured according to the NaCl concentration. The main results obtained are as follows : 1) Under crevice corrosion, the corrosion potential become less noble as the concentration of NaCl solution increased. 2) The current density under open circuit potential was high drained as concentration of NaCl solution increased by 3.5% but the concentration increased over 3.5%, the current density was low drained. 3) The weight loss rate of SS400 was increased as concentration of NaCl solution increased by 3.5% but the concentration increased over 3.5%, that of SS400 was decreased.

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Study on the Characteristics of Crevice Corrosion Prevention of SS 400 in Marine Environment (해양환경 중에서 SS400강재의 간극부식방지 특성에 관한 연구)

  • 임우조;정기철;구영필;윤병두
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2001.05a
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    • pp.152-157
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    • 2001
  • This paper was studied on the characteristics of crevice corrosion prevention of SS 400 in marine environment. In NaCl solution, polarization behavior under the crevice corrosion was investigated. And Weight loss rate of SS 400 applied cathodic protection and non cathodic protection was measured according to the NaCl concentration. The main results obtained are as follows : The weight loss rate of Al-alloy galvanic anode was increased as the concentration of NaCl solution increased by 3.5% but the concentration increased over 3.5%, that of Al-alloy galvanic anode become decreased. The protective potential of SS 400 used Al-alloy galvanic anode becomes more cathodic polarization with increasing concentration of NaCl solution. Effects of oxygen on the weight loss rate of Al-alloy sacrificial anode for cathodic protection as the concentration of 3.5% NaCl solution become sensitive than that of 0% NaCl solution.

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SCANNING ELECTRON MICROSCOPIC STUDY OF THE EFFECT OF ACIDIC DRINK ON ENAMEL EROSION : A CASE REPORT (탄산음료에 의해 부식된 법랑질 표면변화에 대한 증례발표)

  • Kim, Su-Youn;Park, Jae-Hong;Kim, Gwang-Chul;Choi, Young-Chul
    • Journal of the korean academy of Pediatric Dentistry
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    • v.35 no.3
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    • pp.509-515
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    • 2008
  • It is widely believed that the increase in the prevalence of dental erosion is due to soft drinks. The purpose of this study was to assess the influence of soft drinks and etchant on the erosion of tooth enamel and the effect of tooth brushing on the abrasion of eroded enamel, and the effect of milk, saliva and Tooth $Mousse^{(R)}$ on the remineralization. The changes in tooth enamel surface were observed by scanning electron microscophy. The results were as follows; 1. The pH of Coca-Cola and Chilsung-Cider were higher than the pH of FineEtch 37 and $Tyrian^{TM}SPE$. 2. The SEM photos revealed that the pattern of the surface eroded by Coca-Cola and Chilsung-Cider were more obvious than that eroded by etchants. 3. The results of remineralization by saliva, milk, Tooth $Mousse^{(R)}$ were not different from each other. 4. The remineralization by saliva decreased tooth brushing abrasion.

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A Study on Rust Cleaning of Various Industrial Equipment Using Cosmetic and Food Materials (화장품과 식품 재료를 이용한 각종 산업장비 녹(rust) 세정에 관한 연구)

  • Yeom, Seok-Jae;Jung, Sundo;Oh, Eunha
    • Journal of the Korean Applied Science and Technology
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    • v.38 no.1
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    • pp.19-28
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    • 2021
  • Corrosion is the degradation of metals by reaction with the environment. It is difficult to completely remove. Corrosion proceeds rapidly after the protective barrier is destroyed, and several reactions occur that alter the composition and properties of the metal surface and local environments, such as diffusion of metal cations into the matrix, the formation of oxides, and local pH changes. The study of corrosion of steel and iron is of theoretical and practical interest and is receiving considerable attention. Acid solutions, which are widely used in industrial pickling, acid descaling, cleaning and acidification of oil wells, require the use of corrosion inhibitors to suppress corrosion attacks on metallic materials. Physical removal of rust requires expensive special equipment, and chemical removal of it can cause corrosion or shorten the life of the metal. In this study, an eco-friendly rust cleaner was developed using cosmetics and food materials by applying the concept of perm reducing agent and chelate, and applied to remove rust from industrial and hot water pipes and various industrial devices. As a result, it was found that rust cleaners remove rust more effectively and safely compared to conventional treatment methods. At the same time, the rust removal efficiency was 1.75 to 2.5 times better for industrial piping and 1.56 to 2.2 times better for boiler hot water than conventional methods.

Field Investigation of Chloride Penetration and Evaluation of Corrosion Characteristics for Deicer (염화물 침투 현장조사 및 제설제에 따른 부식특성)

  • Yang, Eun-Ik;Kim, Myung-Yu;Park, Hae-Geun
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.6
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    • pp.47-52
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    • 2008
  • Deicer has been generally used for prevention of a road freezing in winter, and the usage amount is increasing every year. However, deicer may induce the decrease of bond strength, surface scaling, and environmental pollution. In this study, the field test was performed to investigate the deterioration of concrete road structures used for 17 years. And, the corrosion resistance characteristics were compared for the existing deicer and eco-friendly deicer. According to the field test results, the penetration depth of limit chloride amount was about 40mm, and the average concentration of chloride was $3.45kg/m^3$ at the surface of structures. On the contrary, the carbonation depth was slight. The penetration depth of eco-friendly deicer was less than the existing deicer, and the corrosion resistance of eco-friendly deicer was higher.

Corrosion Characteristics of a 5Cr-1Mo Steel Specimen by Sodium-Water Reaction (나트륨-물 반응에 의한 5Cr-1Mo Steel 시편의 부식특성)

  • Jeong, Kyung-Chai;Jeong, Ji-Yeong;Park, Jin-Ho;Hwang, Sung-Tai;Kim, Eui-Sik
    • Applied Chemistry for Engineering
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    • v.9 no.7
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    • pp.1023-1029
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    • 1998
  • Small water leak experiment was carried out for the 5Cr-1Mo steel specimen in sodium atmosphere. Perfect re-open time for the leak path of a specimen, by micro leak, was 129 minutes, and its size observed about 2 mm diameter at sodium side. The halos phenomena appeared around of leak spot before the leak path has re-opened, and the size of halos observed was different from the real re-open size of a specimen. Also, the corrosion of a specimen initiated from sodium side, but it did not occur at steam side. In AES analysis, the segregation phenomena of Cr in the specimen was found much more than those of other elements. And also, the sodium compounds formed by sodium-water reaction and deposited onto the leak site of specimen were observed by EPMA analysis and SEM photograph. It is postulated that the corrosion products could be precipitated to form mixed Na Fe Cr compounds.

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A Study for Physical Properties and Corrosion for Metals after Softening of Wood (포화염수 삶음 처리가 목재의 물리적 특성 및 금속 부식에 미치는 영향)

  • Park, Jin Young;Kim, Soo Chul
    • Journal of Conservation Science
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    • v.35 no.6
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    • pp.621-630
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    • 2019
  • A woodblock softening process using saltwater was investigated in order to reduce the cracks and distortion caused by the woodblock-making process and to make the woodblock softer and sculpturing easier. Although anatomical studies of woodblocks have been ongoing for years, little work has been done on softening treatments using natural materials. Hence, the purpose of this paper is to investigate the change in the physical properties of wood treated with saturated brine and the effect of salt on metal nails found embedded in woodblocks. After boiling for twelve h each in water and saturated brine, the saltwater-boiled specimens have longer drying times than the water-boiled specimens. Further, it was observed that salt particles penetrated the cells in the wood. As a result of exposing the copper and iron nails, which were stuck in each specimen, to a high humidity environment, the weight of the saltwater-boiled specimens increased due to the hygroscopicity of the salt. Corrosion of the nails also occurred. This result is similar to the problem that appears on the edge of a woodblock. In conclusion, it was shown that salt in the wood cells affects the corrosion of metal embedded in the wood.

The Study on Corrosion Characteristics of Heat Exchanger Tube for Gas Absorption Refrigeration & Hot Water System (가스흡수식 냉온수기 열교환기용 세관의 부식특성에 관한 연구)

  • Jeong Ki Cheol
    • Journal of the Korean Institute of Gas
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    • v.6 no.1 s.17
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    • pp.92-97
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    • 2002
  • This paper was studied on corrosion characteristics of gas absorption refrigeration & hot water system using $LiBr-H_2O$ working fluids. In the $62\%$ lithium bromide solution at $60^{\circ}C$, polarization test of Cu, $10\%$ cupronickel($90-10\%$ Cu-Ni) and $30\%$ cupronickel($70-30\%$ Cu-Ni) tube was carried out. And polarization behavior, polarization resistance characteristics, open circuit potential, anodic polarization of heat exchanger tube for gas absorption refrigeration & hot water system were considered. The main results are as following: 1) Polarization resistance of heat exchange tubes appears high in order of $30\%$ cupronickel tube > $10\%$ cupronickel tube > Cu tube. B) Open circuit potential of cupronickel tube is more noble than that of Cu tube, and corrosion current density of cupronickel is controlled than Cu tube. 3) Potential of passive region of $30\%$ cupronickel tube is more wide than that of $10\%$ cupronickel tube, and the passivation critical current of $30\%$ cupronickel tube is lower than that of $10\%$ cupronickel tube.

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