• 제목/요약/키워드: corrosion test

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Characteristic of Steel Corrosion in Carbonated Concrete

  • You, JeiJun;Ohno, Yoshiteru
    • Corrosion Science and Technology
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    • 제4권4호
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    • pp.130-135
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    • 2005
  • In this study, accelerated corrosion tests were conducted on concrete specimens with and without accelerated carbonation beforehand for the purpose of elucidating the effects of carbonation, cover depth, and water-cement ratio (W/C) on the reinforcement corrosion. During testing, the corrosion current between the anode steel and cathode stainless steel was measured to continuously monitor the progress of corrosion throughout the test period, thereby investigating the mechanism of reinforcement corrosion and the relationship between corrosion and crack width, as well as other parameters.

실내 가속부식시험을 통한 해양 강관합성 말뚝의 방식 기법 수명 평가 (Evaluation of Life Time for Anti-Corrosive Methods for Marine Steel Sheet by Cyclic Corrosion Test)

  • 박종원;이종구;이경황;김진홍;정문경;이주형
    • Corrosion Science and Technology
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    • 제8권6호
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    • pp.243-250
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    • 2009
  • When a steel sheet pipe applied to marine environment, an anti-corrosive coating should be treated to obtain long-term life-time for steels, especially, splash zone. Although anti-corrosive property of coatings is required to be tested in real marine environment, it is difficult because of long test time such as 20 years or more time. Therefore, we used cyclic corrosion tester in a laboratory, which has similar conditions with salt-dry-wet process such as real marine environment. Anti-corrosive properties of the coatings and two steels were tested their anti-corrosive properties under cyclic corrosion test conditions(KS D ISO 14993) and the results were compared with estimate life-time in real marine environment. According to cyclic corrosion test, accelerated corrosive factor of each anti-corrosive coating was investigated accelerated corrosive factor from impedance with EIS method. Accelerated corrosive factor of type SS400 carbon steel and A690 was also investigated their accelerated corrosive factor from the regression curves of weigh loss results. One of the anti-corrosive coatings showed about 50 years life-time compared with standard sample life-time. Carbon steel SS400 showed from 0.1 mm/yr to 0.06 mm/yr as its corrosion rate.

철근부식상태에 따른 철근콘크리트 보의 슬립특성 (Slip Characteristics of Reinforced Concrete Beams to Corroded Steel State)

  • 권영웅;최봉섭;정용식
    • 콘크리트학회논문집
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    • 제11권6호
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    • pp.129-135
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    • 1999
  • Reinforced concrete structures are constructed under the basic assumption of perfect bonding between steel and concrete. The corrosion of steel in the reinforced concrete beams results in the excessive cracks and gradual deterioration of concrete. This paper are concerned about the slip characteristics of reinforced concrete between steel and concrete. The accelerated test by external power supply was conducted with the three corrosion rates in the laboratory. As a result, it was obtained as follows: (1) the yield strength of steel was reduced according to corrosion states. (2) the equivalent steel area should be considered for detailed analysis. (3) According to the use of corroded steel or not, slip amounts between concrete and steel in test beams increased as the corrosion rate increased. These results can be explained from the bond loss between concrete and steel in test beams.

스프링강의 부식에 미치는 쇼트피닝의 영향 (Influence of Shot Peening on the Corrosion of Spring Steel)

  • 하경준;박경동
    • 한국해양공학회지
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    • 제17권3호
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    • pp.39-45
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    • 2003
  • Shot peening is an effective method of improving the fatigue strength of components and structures. The compressive residual stress produced by surface plastic deformation with shot peening is usually regarded as the major factor in increasing fatigue strength. In this study, the influence of shot peening on corrosion was investigated. Spring steel immersed in $3.5\%$ NaCl prior was used to evaluate the effect of shot peening on fatigue properties. The immersion test was performed on the five kinds of specimens with shot peened and unpeened. The distributions of residual stresses of shot peened spring steels were measured in an X-ray diffraction apparatus, using the two-point method. Corrosion potential, polarization curve, residual stress, etc. were investigated, based on the experimental results. From test results, the effect of shot peening on the corrosion was evaluated.

3 wt% NaCl 수용액에서 알루미늄과 스테인리스강의 부식에 따른 광 반사 거동 (Corrosion and Photo-Reflection Behavior of Aluminum and Stainless Steel During Immersion Test in Salt Solution)

  • 조수연;나현규;조혜리;문종주;안태정;장희진
    • Corrosion Science and Technology
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    • 제19권3호
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    • pp.109-114
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    • 2020
  • The photo-reflectance of aluminum and AISI 304 stainless steel during cyclic immersion test in 3 wt% NaCl solution was examined in this study. Overall, corrosion was not recognized by a visual inspection or weight measurement up to 310 h. When evaluated, it was noted that the roughness of the specimens did not change significantly. However, localized corrosion, which is located at the vicinity of intermetallic precipitation of aluminum or at the grain boundary of stainless steel, was confirmed by the use of an optical microscope and scanning electron microscopy after tens of hours of utilizing the corrosion test. In this respect, an increase of the peak intensity for metallic Al after 90 h of test, and for metallic Fe after 153 h was detected from the X-ray photoelectron spectra. In this context, it was shown that from the photo-reflectance spectra, the reflection of the visible light from the tested samples was changed noticeably over the test duration. As a result, the intensity of reflected light was decreased up to 90 h ~ 153 h, and thereafter was shown to increase higher than the initial intensity before the corrosion test.

인공 체액 조건에서 임플랜트용 티타늄 소재의 부식 특성 (Corrosion Behavior of Titanium for Implant in Simulated Body Fluids)

  • 이중배;최기열
    • 한국표면공학회지
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    • 제37권2호
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    • pp.110-118
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    • 2004
  • The corrosion of pure titanium (CP- Ti Grade 2) and titanium alloy (Ti6Al4V ELI) were studied under various conditions of simulated body fluids. The static immersion test and the electrochemical test were performed in accordance with ISO 10271 : 2001. For the electrochemical test, the open circuit potential was monitored as a function of time, and the cyclic polarization curve was recorded. The corrosion resistance was evaluated from the values of corrosion potential, passivation current density, breakdown potential, and the shape of hysteresis etc. The effects of alloy type, surface condition, temperature, oxygen, and constituents in the fluids such as acid, chloride were estimated. Both specimens had extremely low dissolution rate in the static immersion test. They showed strong passivation characteristics in the electrochemical test. They maintained negligible current density throughout the wide anodic potential range. The passive layer was not broken up to 2.0 V (vs. SCE). The hysteresis and the shift of passivation potential toward the anodic direction was observed during the reversed scan. The passivation process appeared to be accelerated by oxygen in air or that dissolved in the fluids. The passivation also proceeded without oxygen by the reaction of constituents in the fluids. Acid or chloride in the fluids, specially later weakened the passive layer, and then induced higher passivation current density and less shift of passivation potential in the reversed scan. CP-Ti Grade 2 was more reactive than Ti6Al4V ELI in the fluids containing acid or chloride, but thicker layer produced on its surface provided higher corrosion resistance.

무연솔더 동판부식 시험법 연구 (Cu Corrosion Test Method for Lead-Free Solders)

  • 김미송;홍원식;오철민;김근수
    • Journal of Welding and Joining
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    • 제35권3호
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    • pp.21-27
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    • 2017
  • A soldering temperature of ($235{\pm}3$) $^{\circ}C$ is described in ISO 9455-15 for the copper corrosion test. However, this temperature is not suitable for performing lead-free solder pastes. We evaluated the compatibility of a lead-free solder paste in the experimental conditions of (Liquidus temperature + ($35{\pm}3$)) $^{\circ}C$. Based on the results after a Cu corrosion test, a proper temperature for Pb-free soldering was (melting point+($35{\pm}3$)) $^{\circ}C$. Criteria used to evaluate corrosion due to discoloration of flux residue is described in ISO 9455-15, but a more quantitative evaluation standard is needed. In this study, experimental error level was estimated by analyzing flux residue after a corrosion test for 72, 500 hours of specimens using EDS analysis with acceleration voltage. It was determined that the copper area at the flux residue boundary is suitable for the EDS analysis area.

콘크리트 중의 철근방식을 위한 방청제의 적용 (Application of Corrosion Inhibitors to Protect the Corrosion of Reinforcement in Concrete)

  • 문한영;김성수;김홍삼;안기용
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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    • pp.751-754
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    • 1999
  • Corrosion inhibitors are widely used to protect chloride-induced corrosion of reinforcement in concrete. However, the number of researches on the corrosion of reinforcement, when corrosion inhibitor is used, is not enough for actual application in the field. In addition, on corrosion of reinforcement a quantitative standard about corrosion inhibitor does not exist and the data about its influencing concrete are relatively rare. In this study, the effectiveness of rebar corrosion protection, setting time, compressive strength, chloride ion's penetration, and diffusion test were performed using with three different kinds of corrosion inhibitors.

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Effect of Niobium on Corrosion Fatigue Properties of High Strength Steel

  • Cho, Young-Joo;Cho, Sang-Won;Kim, Jung-Gu
    • Corrosion Science and Technology
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    • 제17권2호
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    • pp.81-89
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    • 2018
  • In this study, the effect of Nb alloying element on the corrosion fatigue properties of high strength steel is investigated by conducting fatigue experiments under corrosive condition and hydrogen induced condition, potentiodynamic polarization test, tensile test and surface analyses. Nb element is added to enhance the mechanical property of medium carbon steel. This element forms MX-type phases such as carbides and nitrides which are playing an important role in the grain refinement. The grain refinement is one of the effective way to improve mechanical property because both tensile strength and toughness can be improved at the same time. However, MX-type phase precipitates can be a susceptible site to localized corrosion in corrosive environment due to the potential difference between matrix and precipitate. The obtained results showed that Nb-added steel improved corrosion fatigue property by grain refinement. However, it is degraded for hydrogen-induced fatigue property due to Nb, Ti-inclusions acting as a stronger trap.

슬래브 매입철근의 부식실험 (Corrosion Test for Reinforcement Steels Embedded in Slab Specimen)

  • 류금성;유환구;정영수
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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    • pp.129-134
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    • 1999
  • Recent construction activities and maintenance of marine facilities have been accelerating to keep up with rapid economic growth in Korea. Marine concrete structures are to salts and chloride from ocean environments. The corrosion of reinforcement steel caused by chloride-penetration into concrete may severely affect the durability of concrete structures. the objective of this research is to develop a durable concrete by investigating the resistance of various corrosion protection systems utilizing different water/cement ratio, silica fumes, corrosion inhibitors, etc. A two-year verification test on various corrosion protection system has been doing in the laboratory. Corrosion investigations on reinforcement steel are now under progress for more than 63 concrete specimen. Corrosion-related measurements include microcell corrosion current.

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