• 한국주조공학회지
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• 제18권4호
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• pp.334-339
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• 1998

• Journal of Welding and Joining
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• 제32권5호
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• pp.13-20
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• 2014

A brief overview is given of the corrosion and hydrogen diffusion behaviors of high strength pipe steel in sour environment. Firstly, hydrogen adsorption and diffusion mechanism of the pipe steel is introduced. Secondly, the effect of iron sulfide film precipitated as a result of the corrosion reaction on the steel surface on hydrogen reduction reaction and subsequent hydrogen permeation through the steel is discussed. Moreover, the hydrogen diffusion behavior of the pipe steel under tensile stress in both elastic and plastic ranges is reviewed based on a number of experimental permeation data and theoretical models describing the hydrogen diffusion and trapping phenomena in the steel. It is hoped that this paper will result in significant academic contributions in the field of corrosion and hydrogen related problems of the pipe steel used in sour environment.

• Journal of Microbiology and Biotechnology
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• 제17권9호
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• pp.1558-1562
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• 2007

To elucidate the influence of pipe materials on the VBNC (viable but nonculturable) state and bacterial numbers in drinking water, biofilm and effluent from stainless steel, galvanized iron, and polyvinyl chloride pipe wafers were analyzed. Although no HPC (heterotrophic plate count) was detected in the chlorinated influent of the model system, a DVC (direct viable count) still existed in the range between 3- and 4-log cells/ml. Significantly high numbers of HPC and DVC were found both in biofilm and in the effluent of the model system. The pipe material, exposure time, and the season were all relevant to the concentrations of VBNC and HPC bacteria detected. These findings indicate the importance of determining the number of VBNC cells and the type of pipe materials to estimate the HPC concentration in water distribution systems and thus the need of determining a DVC in evaluating disinfection efficiency.

• 헤리티지:역사와 과학
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• 제48권1호
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• pp.148-165
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• 2015

철은 한반도 고대국가의 형성과 발전에 큰 영향을 미친 중요한 요소였다. 이러한 철을 대규모로 생산하기 위해서는 원료인 철광석과 연료인 목탄의 공급이 원활하고 생산된 철기의 유통을 위해 교통로가 발달된 곳이 적합한 입지로 알려져 있는데, 중원지역은 제철에 필요한 3가지 조건을 모두 갖춘 지역으로 제철유적이 다수 확인되었다. 제철유적에서 확인된 철 생산공정을 검토한 후 진천 석장리유적 B-23호 제철로를 복원하여 제철실험을 실시하였다. 실험은 향후 지속적으로 이루어질 제철실험에 반영할 수 있는 다양한 변수를 파악하기 위한 목적으로 실시하였다. 실험결과 첫째, 배소작업은 철광석의 파쇄에 도움을 주는 것을 재확인하였다. 둘째, 송풍관의 용융과 노내 생성물이 송풍을 방해하는 환경조성에 영향을 주는 것을 확인하였다. 셋째, 철은 탄소와 결합됨에 따라 녹는점이 낮아지며, 성질도 변하기 때문에 연소되는 목탄과 충분히 결합될 수 있는 환경조성이 제철조업에 가장 중요한 요소임을 확인할 수 있었다. 고대 제철기술을 복원하기 위해서는 제철유적에서 확인되는 정보의 철저한 분석과 다양한 가능성을 상정하여 실험에 임하는 자세가 필요하다. 이밖에 철의 생산과 유통을 파악하기 위하여 원료의 산지를 밝히기 위한 연구도 적극적으로 수행되어야 할 것이다.

• 한국수자원학회논문집
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• 제52권8호
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• pp.555-563
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• 2019

상수도관은 시간이 흐름에 따라 부식이 발생할 수 있으며 이로 인해 관두께가 작아져 기존의 성능을 발휘하기 힘들어진다. 이에 본 연구에서는 관두께 변화에 따른 파괴확률을 정량적으로 산정할 수 있는 수치모형을 개발하였으며 이를 실제 상수도관망에 적용하여 사용연수가 증가함에 따라 파괴확률이 어떻게 변화하는지 분석하였다. 파괴확률은 FORM(First Order Reliability Method)를 사용하여 산정되었고 압력의 통계적 특성을 분석하기 위해 여러 가지 다른 시나리오를 이용하여 부정류해석을 수행하였으며 신뢰함수로는 주장력공식을 개선한 KCIP(Korea Cast Iron Pipe)식을 사용하였다. 또한 부식으로 인한 두께변화를 산정하기 위하여 Nahal and Khelif식과 Romanoff의 식을 사용하였으며 이를 통하여 10년, 20년, 30년 후의 부식으로 인한 관두께를 추정하였고 이에 따른 파괴확률을 산정하여 비교분석하였다. 본 연구에서 적용된 상수도관망A의 경우 Nahal and Khelif의 식을 사용하였을 때 100 mm 직경의 강관이 사용연수가 10년, 20년, 30년으로 증가할 경우 파괴확률은 상수도압 $12kg/cm^2$ 일 때 각각 6.8%, 7.8%, 8.5%로 점진적으로 증가하는 것을 알 수 있었고, Romanoff의 식을 사용하였을 경우 6.4%, 7.5%, 8.9%로 증가하는 것을 확인하였다.

• 상하수도학회지
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• 제22권3호
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• pp.379-387
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• 2008

The pH & alkalinity adjustment method by lime and carbon dioxide($CO_2$) for corrosion control in water distribution system was investigated to evaluate the corrosion characteristics of metal pipes, such as galvanized iron, copper, stainless steel, and carbon steel. When the pH in sand filtered and ozone+GAC treated water was increased with lime and $CO_2$ from 7.5 to 8.0, the concentration of residual chlorine decreased at higher pH and longer reaction time; the concentration of trihalomethane increased. The corrosion rate of coupons with corrosion control using lime and carbon dioxide was showed much smaller than those without corrosion control using pilot-scale simulated distribution system. The galvanized iron was corroded much faster than carbon steel, copper, and stainless steel. Especially, copper and stainless steel coupons were hardly corroded. The galvanized iron and carbon steel coupons with corrosion control were produced the corrosion products less than those without corrosion control by the results of environmental scanning electron microscope(ESEM) and energy dispersive x-ray spectroscopy(EDS) analyses. The galvanized iron coupon with pH and alkalinity adjustment by lime and carbon dioxide was detected about 30 percent of zinc, when the carbon steel was detected about 30 percent of calcium by calcium carbonate products formation. For the results of X-ray diffraction(XRD) analyses, the goethite(${\alpha}$-FeOOH) was identified as primary corrosion product of galvanized iron without corrosion control, while the Zinc oxide(ZnO) was found on corrosion products of galvanized iron coupon with corrosion control as the results of EDS analyses. However, the carbon steel corrosion products regardless of corrosion control were composed predominantly of maghemite(${\gamma}-Fe_2O_3$) and hematite(${\alpha}-Fe_2O_3$).

• 설비공학논문집
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• 제30권1호
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• pp.44-49
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• 2018

High-strength plastic water supply pipe evaluation method was evaluated in this study. Up to date, high strength water supply pipes that we install are mostly ductile cast iron pipes. Sometimes, a few PVC pipes are installed. Metal pipes have rust problem on the surface, causing serious damage to metal pipes and reducing the expected life span of water piping system. Nowadays, depending on technology development, some companies have improved properties of general PVC pipe performance with remarkable properties that exceed KS and ASTM standard. Here, we suggest a new method of performance evaluation for high-strength water plastic pipes.

• 환경위생공학
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• 제17권4호
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• pp.53-60
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• 2002

This experiment was performed to investigate the characteristics of corrosion mechanism of water steel pipes using SEM(Scanning Electron Microscope) from March 1. 2002 to November 30. The characteristics shown in these results can be summarized as the following: 1. When I investigated to the characteristics of iron pipes and zinc pipes using a SEM, I could be found that there was a distintion in interface between an iron pipe and the scale, and that a zinc pipe wears a dark color. 2. I find much rate of $Fe_2O_3$ and a little rate of FeS as corrosion products, but I hardly find $FeCO_3$without carbon. 3 It was found that the oxide corrosion rate was 0.2~0.3mm/year. And then A-1 was 0.323mm/year that was very high.

• 한국안전학회지
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• 제23권5호
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• pp.79-83
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• 2008

The corrugated stainless steel tubing(CSST) for the fuel gas piping system can be installed easily and quickly. It is often constructed under the ceiling and the wall which has a good flexibility and installation in comparison with iron pipe. However, the quality of the CSST is determined to depend upon the welding skill of stainless steel tubing. In this study, it is tested by controlling jet point of Ar as inert and cooling gas, and also compared with the bead state of welding point and the performance. As a result, it has the best condition when the jet point of Ar is located behind $5{\sim}10mm$ of the welding point.

• Corrosion Science and Technology
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• 제19권4호
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• pp.224-230
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• 2020

Stainless steel has excellent corrosion resistance. The drawback is that pitting occurs easily due to the concentration of chloride. In addition, corrosion of socket weld, which is structurally and chemically weaker than the other components of the pipe, occurs rapidly. Since these two phenomena overlap, pinhole leakage occurs frequently in the seawater pipe socket welds made of stainless steel at the power plants. To analyze this specific corrosion, a metallurgical analysis of the stainless steel socket welds, where the actual corrosion occurred during the power plant operation, was performed. The micro-structure and chemical composition of each socket weld were analyzed. In addition, selective corrosion of the specific micro-structure in a mixed dendrite structure comprising γ-austenite (gamma-phase iron) and δ-ferrite (iron at high temperature) was investigated based on the characteristic micro-morphology and chemical composition of the corroded area. Finally, the different corrosion stages and characteristics of socket weld corrosion are summarized.