• Corrosion Science and Technology
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• 제11권3호
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• pp.71-76
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• 2012

Computational fluid dynamics (CFD) is nowadays a powerful and reliable tool for simulating different flow processes and temperature. CFD is used to analyze the various pot geometries and operative variables in 55% Al-Zn pot of CGL. In this research, different strip velocities were assumed and then shown the flow pattern in the pot that was similar in the different strip velocities. Temperature distribution in the pot depended on inductors and inlet strip temperature at the steady condition. Generation of dross particles and transport models were considered to describe dross particles evolution inside the pot. In order to observe dross influence by scrap location, dross particles were generated upon the sink roll. Floating time of dross particles is different by scraper locations above the sink roll.

• Corrosion Science and Technology
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• 제23권2호
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• pp.83-92
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• 2024

A hot-dip simulator was utilized to replicate abnormal coating buildup observed during line stops at galvanize lines, assessing the influence of processing conditions on buildup (up to 14 mm/side). Steel samples from 19 coils (comprising IF, BH, LCAK, HSLA, DP600-DP1180, Si: 0.006 - 0.8 wt%, P: 0.009 - 0.045 wt%) were examined to explore the phenomenon of heavy coating growth. It was discovered that heavy coating buildup (~3 mm/h) and rapid strip dissolution (~0.17 mm/h) in a GA or GI pot can manifest with specific combinations of steel chemistry and processing conditions. The results reveal the formation of a unique coating microstructure, characterized by a blend of bulky Zeta crystals and free Zn pockets/networks due to the "Sandlin" growth mechanism. Key variables contributing to abnormal coating growth include steel Si content, anneal temperature, dew point in heating and soaking furnaces, Zn pot temperature, Zn bath Al%, and cold-rolling reduction%. At ArcelorMittal Dofasco galvanize lines, an automatic online warning system for operators and special scheduling for incoming Si-bearing steels have been implemented, effectively preventing further heavy buildup occurrences.

• 한국표면공학회지
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• 제32권1호
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• pp.21-30
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• 1999

Coating adherance behavior of low carbon steels, produced by POSCO, Korea, was studied in order to study the characteristics of hot rolled galvanized iron(HGI) manufactured without pickling line and the development of its process. Galvanizing experiments were carried out in zinc pot with 0.2wt% Al after hot rolled plates with scale were reduced at $550~750^{\circ}C$ in 10~30% hydrogen gas atmosphere during 60~400seconds. The reduced plates and coated products were examined by SST, XRD, SEM and EPMA on their surfaces and cross sections. Coating layer of HGI manufactured with pickling line was composed of retained scale, Fe-Zn-Al compound, Fe-Zn compound ($\delta_1\;and\;\zeta$ Phase) and pure zinc. It was superior to HGI in coating adhesion. It seems to be due to forming of Fe-Zn-Al compound in interface of matrix and retained porous scale.

• 한국표면공학회지
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• 제36권5호
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• pp.364-372
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• 2003

In continuous galvanizing process, dissolution of iron into molten zinc results in a fairly great amount of dross. In order to decrease dross, the amount of dissolved iron of strip in molten zinc was investigated in the range of 0∼0.22%Al content, 440∼$470^{\circ}C$ strip temperature and 3∼60 sec dipping time. Uniform Fe-Al-Zn inhibition layer was formed in the coating layer/strip interface not only in the grain boundary but also in the grain of substrate with the increase of Al content in the zinc pot, while the amount of iron dissolution was decreased. Inhibition layer was unstable as the dipping time and strip temperature increased and the amount of iron dissolution increased.

• 아시안잔디학회지
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• 제16권1호
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• pp.1-10
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• 2002

Creeping bentgrass 'Penn-Al', Perennial ryegrass 'Palmer ll', Kentucky bluegrass 'Nassou', Tall fescue 'Boonsai 2000'의 생육에 대한 칼슘의 영향을 온실에서 조사하였다. Creeping bentgrass 'Penn-Al', Kentucky bluegrass 'Nassou'와 Tall fescue'Boonsai 2000'의 shoot 생육은 Ca 4.0me/L에서, Perennial ryegrass 'Palmer II'는 Ca 2.0me/L.에서 가장 양호하였다. Creeping bentgrass 'Penn-Al', Perennial ryegrass 'Palmer II'와 Kentucky bluegrass 'Nassou'의 뿌리생육은 Ca 1.0me/L, Tall fescue'Boonsai 2000'는 Ca 4.0me/L에서 가장 양호하였지만 처리간에 큰 차이는 없었다. Creeping bentgrass 'Penn-Al'와 Kentucky bluegrass 'Nassou'의 분얼수는 Ca 4.0me/L., Perennial ryegrass 'Palmer II'는 Ca 1.0me/L에서 가장 많았으며, Tall fescue 'Boonsai 2000'의 분얼수는 Ca 4.0me/L에서 가장 많았지만 처리간 유의성은 없었다. 식물체 내 무기성분 함량은 Ca 처리 농도가 높을수록 Ca 함량이 많았고, 반대로 Mg 함량은 감소하였으며, Fe는 Ca 4.0me/L까지는 함량이 증가하였고, N, P, K, Zn는 큰 영향이 없었다. 식물 영양실험에 있어서 심지화분의 이용성은 정확도와 간편성이 탁월하여 앞으로의 연구에 많이 적용될 수 있음을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1445-1453
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• 2013

$Zn_{(1-x)}Ni_xAl_2O_4$ (x = 0.0-1.0) spinels were prepared at $800^{\circ}C$ by co-precipitation method and characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The specific surface area was determined by BET. SEM image showed nano sized spherical particles. XPS confirmed the valence states of the metals, showing moderate Lewis character for the surface of materials. The powders were successfully used as new heterogeneous catalysts of Biginelli's reaction, a one-pot three-component reaction, leading to some dihydropyrimidinones (DHPMs). These new catalysts that produced good yields of DHPMs, were easily recovered by simple filtration and subsequently reused with persistent activity, and they are non-toxic and environmentally friendly. The optimum amount of catalyst is 20% by weight of benzaldehyde derivatives, while the doping amount has been found optimal for x = 0.1.

• 한국토양비료학회지
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• 제24권1호
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• pp.69-76
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• 1991

토양(土壤)의 pH, 유기물(有機物), 유효인산함량(有效憐酸含量)과 양(陽)이온 치환용량(置換容量)이 낮은 신개간지(新開墾地) 야산토양(野山土壞)에 석회(石灰) 및 석회(石灰)+인산(燐酸)을 시용(施用)하고 대두(大豆)를 pot재배(栽培)하여 대두(大豆)의 생육(生育), 식물체중(植物體中) 전질소함량(全窒素含量), amide태(態)및 ureide태질소(態窒素)와 근류수(根瘤數) 및 토양미생물상(土壤微生物相) 등(等)에 미치는 영향(影響)을 구명(究明)하고자 시험(試驗)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 석회(石灰)+인산시용(燐酸施用)으로 대두(大豆)의 초장(草長), 경태(徑太)등은 대조구(對照區)에 비(比)하여 현저(顯著)히 증가(增加)되었으며, 특(特)히 지상부(地上部) 및 지하부(地下部)의 건물생산량(乾物生産量)과 토착(土着) 근류(根瘤)의 무게는 처리간(處理間)에 고도(高度)의 유의차(有意差)가 있었다. 2. 식물체중(植物體中) amide태질소(態窒素)의 시간별(時期別) 농도변화(濃度變化)는 파종(播種) 후(後) 45일(日)에는 대조구(對照區)〉석회(石灰)>석회(石灰)+인산(燐酸) 순(順)이었고, 개화기(開花期)에는 석회(石灰)+인산(燐酸)〉석회(石灰)>대조구(對照區) 순(順)이었다. 3. 식물체중(植物體中) ureide태질소(態窒素)는 엽중(棄中)의 농도(濃度)가 파종후(播種後) 45일(日)때에는 대조구(對照區)>석회(石灰)>석회(石灰)+인산(燐酸) 순(順)이었고, 개화기(開花期)에는 석회(石灰)+인산(燐酸)>석회(石灰)>대조구(對照區) 순(順)이었다. 그러나 줄기에서는 그 반대(反對)의 순(順)으로 나타났으며 각(各) 시기 모두 치리간(處理間) 유의(有意)한 차이(差異)가 있었다. 4. 미생물(微生物)의 활성(活性)은 석회(石灰)와 인산(燐酸)의 시용(拖用)으로 토양(土壤) pH, 유효인산(有效憐酸) 및 치환성(置換性) 염기함량(鹽基含量)이 증가(增加)됨에 따라 높아졌다. 5. 개화기(開花期) 엽중(葉中)의 amide태질소(態窒素)는 대두생육(大豆生育), 토양중(土壤中) Al 및 Fe함량(含量)과는 부(負)의 상관을 ureide태질소(態窒素)와 대두생육량(大豆生育量)과는 정(正)의 상관(相關)을, 식물체중(植物體中) Al 및 Zn함량(含量)과는 부(負)의 상관(相關)을 보였다.