In recently, the method estimated construction's defeat using the infrared thermography was prefer to method of new repair and estimate as a good point that simple of application and save labor, what is more economic than other techniques and can reduce need time. The purpose of this study is to develope the technique to measure the corrosion of reinforcing bars using the infrared thermal photography graphic data. In this page, the former final purpose establishment that galvanic corrosion method of reinforced bars and infrared thermography system, and studied trend of thermography and photography graphic data by parameters of corrosion of specimens, atmosphere temperature, concrete cover depth etc.

본 논문은 국내 PWR 발전소에서 S/G tube 재질로 사용되고 있는 Inconel 600 및 690에 대한 부식 실험을 수행함으로써 작업자들의 주요 피폭원인 의 생성량을 예측하고자 하였다. 이를 위해 Inconel 600 및 690 재질로 총 12개의 시편을 제작하여 실제 발전소의 운전조건과 유사하거나 가혹한 조건에서 전면 부식실험을 pH별로 20일씩 총 60일간 수행하였고, 실험 결과를 정량적으로 분석하기 위해 GDS(Glow Discharge Spectrometer) 장비를 사용하였다. GDS 장비를 이용하여 정량적으로 분석한 결과 pH 7 및 9에서는 Inconel 600이 Inconel 690에 비해 부식이 잘 되는 것으로 나타난 반면, pH 4에서는 Inconel 690이 부식이 더 잘 되는 것으로 평가되었다. 이러한 경향을 보이는 것은 과도상태의 영향이 과도하게 반영된 것에 기인한 것으로 비교적 정확한 결론을 도출하기 위해서는 장시간의 부식 실험을 수행함으로써 과도상태에 의한 영향을 최소화해야 할 것으로 판단된다.

The stress corrosion cracking (SCC) susceptibility of Alloy 600 MA, Alloy 600 TT, Alloy 800, and Alloy 690 TT were investigated in a deaerated 0.01 M solution of sodium tetrathionate using reverse u-bend test samples at . The results showed that SCC occurred in all alloys, excluding Alloy 690 TT. The SCC susceptibility decreased with an increase in the chromium content of the alloys. The results of the deposits and spectra taken from an energy dispersive X-ray system confirmed the existence of a reduced sulfur causing SCC.

This work presents mechanical properties and corrosion resistance of duplex stainless steels obtained through powder metallurgy starting from austenitic, martensitic powders by controlled addition of alloying elements in the right quantity to obtain the chemical composition of the structure similar to biphasic one. In the mixes preparations the Schaffler's diagram was taken into consideration. Prepared mixes of powders have been sintered in a vacuum furnace with argon backfilling. After sintering rapid cooling was applied using nitrogen. Corrosion properties have been studied through electrochemical methods in 1M NaCl.

The corrosion performance of a powder metallurgical aluminum alloy in aeronautical environments was studied for both as sintered and heat treated states. Sintered samples were obtained by uniaxial pressing of an Al-Cu-Mg prealloyed powder followed by liquid phase sintering. The heat treatments applied were T4 and T6. Corrosion behaviour was assessed by means of potentiodynamic polarization. Results for the equivalent commercial wrought counterpart, AA2024-T3, are also presented for comparison. Similar corrosion performance was observed for both as sintered and AA2024-T3 samples, while corrosion resistance of the PM materials was improved by the heat treatment, especially in the T4 state.

Injection molding of corrosive super engineering plastics and engineering plastics with various fillers is conducted under severe conditions and causes corrosion and wear problems. We have developed boride base cermets, which have excellent corrosion-and wear-resistances, and tried to apply them into plastic molding machine parts. In this paper, the effects of V substitution for Cr on the mechanical properties, corrosion resistance and microstructure of Ni-5.0B-51.0Mo-(17.5-X)Cr-XV (mass%) model cermets were investigated. Both transverse rupture strength (TRS) and hardness increased monotonically with increasing V content and reached 2.94GPa and at 10.0%V, respectively. The improvements of TRS and hardness were attributed to microstructural refinement.

The likelihood of failure by the corrosion of high temperature H2S/H2, which affect to a risk of facilities, was analyzed through the risk based-inspection using API-581 BRD. We found that the corrosion rate was increased as temperature and H2S concentration were increased. Also, the technical module subfactor(TMSF) was increased as an used you increased, material thickness decreased, inspection number decreased, and inspection effectiveness increased. In these conditions, the maximum value of TMSF was not varied, but the TMSF was sensitively varied at low temperature for high concentration of H2S.

Corrosion level of reinforcing bar is investigated in this study. Seventy-two specimens are designed with 12 different target corrosion levels, two types of reinforcing bars, 3 different concrete covers. Corrosion current density, corrosion potential and ohmic resistance of concrete are measured on these specimens using Gecor device. Metal loss measurements are performed in accordance with ASTM G1-90[1], method C3.5[2], after specimens cracked. The actual corrosion weight loss of the steel reinforcing bars is then compared to the result obtained from the corrosion level measurement. Finally, the estimation of corrosion level can be made using electrical potential and current intensity measured. The experimental results show that the actual corrosion levels of steel bars embedded in concrete are less than the expected corrosion levels. And non-destructive corrosion measurement technique is applicable in order to assess corrosion level in reinforcing bars. This study suggests the relationship between corrosion level and measured electrical potential and measured current intensity.

The likelihood of failure for the thinning of high temperature sulfide and naphthenic acid corrosion, which affect to a risk of facilities, was analyzed through the risk based inspection using API-581 BRD. We found that the corrosion rate was increased with increasing temperature and total acid number(TAN). And maximum value of the technical module subfactor(TMSF) was not varied with operating condition, but the TMSF was sensitively changed at the range of low temperature, low flow rate, and high TAN. Also, the TMSF was increased as an used year and inspection effectiveness increased, but it was increased as thickness, inspection number, and over design decreased.

자기필터시스템을 이용한 원자로 냉각재로부터의 방사성 부식생성물 제거는 원자력 발전소의 운전 및 유지보수 종사자에 대한 방사선 피폭 준위를 낮추는 방법으로 많은 연구가 이루어지는 분야 중 하나이다. 그 결과, 보다 높은 신뢰성과 여과성능을 갖춘 자기필터를 개발하고자 수화학 분야에서는 많은 연구가 이루어지고 있다. 본 연구에서는 부식생성물의 자기적 성질을 이용하여 원자력 발전소 냉각재내의 방사성 부식생성물을 제거하기 위해 영구자석과 전자석 이 조합된 자기필터 시스템을 개발하였다. 영구자석은 부식생성물의 여과를 위해 사용되며 전자석은 아주 미세한 콜로이드 부식생성물 입자의 크기를 증가시키기 위한 응집에 이용된다. 선행 연구에서 영구자석만을 사용한 필터 실험결과 대부분의 부식생성물 입자에 대해 만족할만한 수준의 제거효율을 달성하였으며 특히, 크기가 5m 이상인 입자의 경우 제거효율은 90를 상회하였다. 전자석을 이용한 응집 실험결과 화학응집제의 첨가 없이 대부분의 부식생성물 입자가 전자기장에 의해 응집하여 크기가 5m 이상으로 증가되어 응집실험에 대해 전반적으로 만족스러운 결과를 도출하였다. 따라서, 영구자석과 전자석이 조합된 자기필터시스템은 방사성 부식생성물 제거를 위한효과적인 방법으로 높은 제거효율을 보여주리라 여겨진다.

In order to enhance the quality of the glass bottle and to preserve the contents long, corrosion of the bottle surface is often required. The corrosion operation consists of dangerous and harmful tasks using strong acid such as HF. Thus, the corrosion operation should be automatized to improve the worker's safety. The first step of the automation is to develop the bottle gripping system that automatically grips and fixes the bottle during corrosion operations. The gripping system consists of holders, holder plates, air cylinders, and bottle aligning system. This paper shows the gripping system development procedure.

A series of reinforced G109 type specimens was fabricated and cyclically ponded with a15 w/o NaCl solution. The concrete mix design included cements of two equivalent alkalinities (0.32 and 1.08) and water cement ratio 0.50. Potential and macro-cell current between top and bottom bars were monitored as indicators of the onset of active corrosion. The specimens were subsequently autopsied, and the number and size of air voids along the top half of the upper rebar trace were counted, both at the corrosion site and where the steel remained passive. Also, chloride concentration was determined from powder samples taken from passive locations along the upper rebar trace. The observations and data indicated that both cement alkalinity and air voids aftected occurrence of active corrosion. The results are discussed within the context of better understanding factors that cause loss of passivity and active corrosion of steel in concrete.

Likelihood of failure for the external corrosion of carbon and low alloy steels, which affect to a risk of facilities, was analyzed quantitatively through the risk based inspection using API-581 BRD. We found that the technical module subfactor (TMSF) decreased as the inspection number increased and it increased as the Inspection effectiveness and the used year increased. In this condition, the TMSF showed high value for the case of the marine/cooling tower drift area as a corrosion driver, poor quality of coating, no insulation, and low insulation condition.