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- 저자 : 위재용 ( Jae-lyoung Wi ) (검색결과 4 건)
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포스터 전시회 : 해수용 열교환기 표면의 내식성 향상을 위한 표면처리 기법
위재용 ( Jae Lyoung Wi ),김대윤 ( Dae Yun Kim ),이성혁 ( Seong Hyuk Lee ) 한국액체미립화학회 2013 한국액체미립화학회 학술강연회 논문집 Vol.2013 No.-
This article introduces a new challenging technique for anti-corrosion surface treatment using nitriding method in sea-water heat exchangers. As a matter of fact, most of sea-water exchangers have chosen titanium for enhancement of corrosion resistance, but the use of titanium requires very high cost in making the heat exchanger. Hence, the present study suggests such an alternative for cost reduction in making sea-water heat exchanger by using the well-known nitriding technique. In order to examine the furnace performance, the CFD simulations were extensively conducted for the nitriding furnace during the procedure and the predicted distributions of NH3 and temperature fields were provided for ensuring the uniformity inside the furnace. After surface treatment, SEM images were captured to predict the thickness of nitriding layer and the treated samples were evaluated by the the SST (salt spray test) method. From the results, it was shown that the corrosion resistance was substantially enhanced by the present surface treatment method.
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산질화로 내에서 유동장 및 온도장에 미치는 입구가스온도와 팬속도의 영향
박재용 ( Jae Yong Park ),위재용 ( Jae Lyoung Wi ),이성혁 ( Seong Hyuk Lee ) 한국액체미립화학회 2014 한국액체미립화학회 학술강연회 논문집 Vol.2014 No.-
The oxinitrocarburusing method is one of the well-established coating methods for making compound and oxidation layers on the steel surfaces. In fact, this method has been widely used for the improvement of wear, corrosion and fatigue resistance of constructional parts. The estimation and control of oxidation and compound layer thicknesses is one of the main factors in evaluating coating quality through the heat treatment. The thickness closely depends on uniform temperature distributions of reaction gases in the furnace. Thus, accurate estimation of gas flow characteristics in the furnace would be useful in designing the furnace and determining the operation conditions. Unfortunately, experimental tests are actually impossible because of very high gas temperature and the existence of toxic gases during the process. Hence, with the use of the commercial CFD code (FLUENT V. 13.), the present study carried out extensive numerical simulation for the real furnace and then analyzed temperature distributions and gas flow characteristics which are affected by various parameters such as fan speed and inlet gas temperature. From the results, it was found that the gas temperature increased with the fan speed and the temperature difference between bottom and top surfaces of the furnace gradually decreased as the fan speed increased. Also, it was seen that the inlet gas temperature and the increase in fan speed would affect the spatial uniformity of gas temperature in the furnace.
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박재용(Jaeyong Park),위재용(Jae Lyoung Wi),이성혁(Seong Hyuk Lee) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
The oxi-nitrocarburizing have well been known one of the well-established thermochemical surface treatments used to improve wear and corrosion resistance as well as fatigue endurance of steel parts. The thicknesses of the compound and oxidation layers formed by oxi-nitrocarburizing are one the key factors in evaluating the quality in the heat treatment process. The thickness closely depends on uniformity of temperature and gas concentration in the furnace. With the use of the commercial computational fluid dynamics code (CFD, FLUENT v.16.1), the present study carried out numerical simulations for the in-service furnace to examine the temperature distributions and gas flow characteristics varied with the fan speed effect. In addition, the Kn factor, which is defined as the ratio of the partial pressure of ammonia and hydrogen, were calculated on the basis of numerical results. It was found that the uniformity of gas temperature in furnace were gradually improved as the fan speed increased. This is because that high turbulent intensity increased heat transfer on the region of high temperature deviation. Moreover, the Kn factor would be affected by the ammonia dissociation rate and flow rate of ammonia gas.
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AISI1045 기계구조용 탄소강의 질화 가스분위기에 따른 화합물층의 형성 및 조직변화
이원범 ( Won-beom Lee ),유광춘 ( Kwang-chun Yu ),김영민 ( Young-min Kim ),위재용 ( Jae-lyoung Wi ) 대한금속재료학회(구 대한금속학회) 2016 대한금속·재료학회지 Vol.54 No.7
Compound layers developed at 520 ℃ during gaseous nitriding of AISI 1045 steels were investigated. The nitriding potential (Kn) of a gas atmosphere of dissociating ammonia gas was checked by observation of the partial pressure of hydrogen gas. The microstructural evolution of the compound layer was studied by using optical microscopy and scanning electron microscopy. It was observed that the surface hardness was about 600 Hv after the nitriding treatment and the case depth was about 0.5mm after a nitriding treatment of 1440 min. The compound layer was composed of ′(Fe4N) and ε(Fe2-3N). The thickness of the compound layer was simultaneously increased to 16 μm during the nitriding treatment of 1440 min. The kinetics of the compound layer growth were discussed with a modified Lehrer diagram of AISI 1045 steels, which was obtained from the thermodynamic calculation. †(Received January 15, 2016; Accepted March 2, 2016)
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