• Title/Summary/Keyword: Marine characteristics

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Effects of alloy elements on electrochemical characteristics improvement of stainless steel in sea water (해수환경하에서 스테인리스강의 전기화학적 특성 개선을 위한 합금원소의 영향)

  • Lee, Jung-Hyung;Choi, Yong-Won;Jang, Seok-Ki;Kim, Seong-Jong
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.7
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    • pp.890-899
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    • 2014

  • Austenitic stainless steel is widely used in various industries due to its excellent corrosion resistance. However, Cr carbides precipitation along the grain boundaries after heat treatment or welding may develop Cr depleted zone, which acts as a preferential site for intergranular corrosion attack. To resolve this, carbon stabilizing element such as Ti or Nb are added to suppress formation of Cr carbides. However, there are few reports on corrosion characteristics under seawater environment of the stabilized stainless steel. This study investigated the effects of alloying contents on the electrochemical characteristics in seawater of stainless steel containing stabilizing element(Ti and Nb). To achieve this, the changes on the microstructure due to alloying were observed with microscope, and the electrochemical characteristics were determined by measurement of natural potential and potentiodynamic polarization experiments. The microscopic observation revealed that all specimens had inclusions other than the austenite matrix phase due to the addition of alloying elements. Such inclusions are considered to have different electrochemical characteristics from those of the matrix, and thus a clear distinction was found according to the type of stabilizers and the contents. The results of this study suggest that it is important to consider the effects of alloying contents on the electrochemical characteristics in seawater with the addition of Ti or Nb into austenitic stainless steel.

  • https://doi.org/10.5916/jkosme.2014.38.7.890 인용 PDF KSCI

Modeling the Resident Characteristics of Land-Based Pollutant Inflow to Suyeong Bay (수영만으로 유입되는 육상기인 오염물질의 체류특성 모델링)

  • Jung, Woo-Sung;Hong, Sok-Jin;Lee, Won-Chan;Kim, Hyung-Chul;Kim, Jin-ho;Kim, Dong-Myung
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.25 no.1
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    • pp.45-57
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    • 2019

  • The resident characteristics of land-based pollutants were analyzed to manage the pollution sources affecting Suyeong Bay. These characteristics were analyzed using a hydrodynamic model and particle tracking model. Pollutants were represented by particles, and the amount of particles and pollutants was represented proportional. The resident characteristics were analyzed by comparing the amount of pollutant load, resident pollutants, and the ratio of resident pollutants remaining in the bay relative to the incoming load for each the of pollution sources. The order of the pollution sources was as follows, according to the amount of resident pollutants at Suyeong Bay. the Suyeong WasteWater Treatment Plant(WWTP), Nambu WWTP, Suyeong river and so on. The amount of resident pollutants was smaller for small load farther away from the interior of bay. Nambu WWTP had the greatest load among the pollution sources, but it showed the smallest ratio of pollutants remaining in the bay relative to incoming load among the pollution points. The result indicates that pollutants affect sea areas differently according to the characteristics each area and the topographic characteristics of pollution sources.

  • https://doi.org/10.7837/kosomes.2019.25.1.045 인용 PDF KSCI

Evaluation of Cavitation Characteristics for ALBC3 Alloy Coated with Ni-Cr Series Self Fluxing Alloy in Marine Environment (해양환경 하에서 Ni-Cr계 자용성 합금 코팅된 ALBC3 합금의 캐비테이션 특성 평가)

  • Lee, Seung-Jun;Kim, Seong-Jong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.19 no.5
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    • pp.538-544
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    • 2013

  • In this study, cavitation characteristics of a thermal spray coating were evaluated in order to improve durability and cavitation resistance. For a coating material, a Ni-based self-fluxing alloy was thermal-sprayed over a ALBC3 alloy substrate and subsequently modified by heat treatment.The resulted self-fluxing coating layer had relatively high hardness compared to the base material, and thus would be expected to exhibit good durability. However, the cavitation characteristics were deteriorated due to the intrinsic porous structure of the coating. Therefore, it is essential to optimize heat treatment condition during thermal spraying coating process for self-fluxing alloy, and in this research the increase in heat treatment temperature is thought to increase the fluidity of B and Si in the self-fluxing alloy and to remove pores or defects, leading to the characteristics enhancement.

  • https://doi.org/10.7837/kosomes.2013.19.5.538 인용 PDF KSCI