• Corrosion Science and Technology
• /
• v.11 no.3
• /
• pp.71-76
• /
• 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
• /
• v.23 no.2
• /
• pp.83-92
• /
• 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.

• Journal of the Korean institute of surface engineering
• /
• v.32 no.1
• /
• pp.21-30
• /
• 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.

• Journal of the Korean institute of surface engineering
• /
• v.36 no.5
• /
• pp.364-372
• /
• 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.

• Asian Journal of Turfgrass Science
• /
• v.16 no.1
• /
• pp.1-10
• /
• 2002

The influence of calcium on the growth of creeping bentgrass 'Penn-Al', perennial ryegrass 'Palmer II', Kentuckuy bluegrass 'Nassou' and tall fescue 'Boonsai 2000' in greenhouse was investigated. Creeping bentgrass 'Penn-A1', Kentucky bluegrass 'Nassou' and tall fescue 'Boonsai 2000' at Ca 4.0 me/L, and perennial ryegrass 'Palmer II' at Ca 2.0 me/L showed the best shoot growth. Creeping bentgrass 'Penn-A1', perennial ryegrass 'Palmer II' and Kentucky bluegrass 'Nassou' at Ca 1.0 me/L, and tall fescue 'Boonsai 2000' at Ca 4.0 me/L showed the best root growth, and there was little or no difference between different Ca concentrations. Creeping bentgrass 'Penn-Al' and Kentucky bluegrass 'Nassou' at Ca 4.0 mea, and perennial ryegrass 'Palmer II' at Ca 1.0 me/L had the highest number of tillers, and tall fescue 'Boonsai 2000' at Ca 4.0 me/L had the highest, but there was no difference between different Ca concentrations. As application rate of Ca concentration became higher, the concent of Ca in plant tissue increased, while the content of Mg in plant tissue decreased, and the content of Fe in plant tissue increased to Ca 4.0 me/L. The Ca treatment had not effect on N, p, K, and Zn of tissue content. The wick pot applied will be to research of plant nutrition in future because utilization of wick pot has an excellent precision and convenience.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.5
• /
• pp.1445-1453
• /
• 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.

• Korean Journal of Soil Science and Fertilizer
• /
• v.24 no.1
• /
• pp.69-76
• /
• 1991

A pot experiment was conducted to find out the effects of lime and phosphate application on the changes of number of soil microorganisms, indigenous Rhizobium japonicum, nodule formation, and ureide-and amide-N in leaf and stem exudate of soybean plant under uncultivated hillside red earth in very low pH value, organic matter, available phosphate, and cation exchange capacity. The results obtained were summarized as follows : 1. The plant height, stem length, root dry weight and nodule weight were significantly increased with the application of lime and phosphate application than that of control plot. 2. The concentration of amide-N in soybean plant at the 45 days after sowing was obtained as high in order of control>lime> lime+phosphate while the concentration was obtained in order of Iime+phosphate>lime> control at flowering stage 3. However, concentration of ureide-N in the soybean leaf at the 45 days after sowing was obtained as high in order of control>lime>lime+hosphate while reversed concentration was obtained in stem. 4. The number of soil microorgan isms were increased with increase of pH value, available phosphate and soil exchangeable cation. 5. Significantly negative high correlation were obtained with the concentration of Al, Fe in soil and the concentration of amide-and ureide-N in soybean plant at flowering stage while positive correlation was obtained with plant growth and the concentration of ureide-N.