• Title/Summary/Keyword: 알루미늄 도금강판

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Effects of Zinc and Aluminum Hot-dip Galvanized Sheet Steel on the Gill and Hepatopancreas of the Abalone Haliotis discus hannai (아연 및 알루미늄 용융도금 처리된 강판이 북방전복(Haliotis discus hannai)의 아가미와 간췌장에 미치는 영향)

  • Lee, Chi Hoon;Park, Jun Young;Lee, Young Don
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.50 no.4
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    • pp.388-395
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    • 2017
  • We investigated the toxicity of zinc and aluminum hot-dip galvanized sheet steel to abalone Haliotis discus hannai via changes in the gill and hepatopancreas using histological and transmission electron microscopy analysis. Experimental groups were composed of one control and four exposure conditions (direct or indirect exposure to zinc and aluminum hot-dip galvanized sheet steel). In the control group, aluminum exposure groups (direct and indirect), and indirect zinc exposure group, abalone mortality was not observed until the end of the experiment, and no histopathological changes were observed in the gill and hepatopancreas. However, the direct zinc exposure group exhibited 100% mortality. Ultrastructural analysis of the cytoplasm of ciliated and microvilli-bearing epithelial cells from gill filaments revealed electron-dense vesicles near the cell membrane and disruption of the nuclear membrane. We also observed swollen mitochondria and a loss of mitochondrial cristae. The hepatopancreas showed similar changes, and we detected highly electron-dense particles within the vesicles. These results suggest that abalone exposed directly to zinc hot-dip galvanized sheet steel experience acute toxicity, causing damage to cell organelles in the gill and hepatopancreas and, finally, inducing mortality.

Effects of Al and Mg on the Microstructure and Hardness of the Coating Layer of Hot-dip Galvanized Steel Sheet (알루미늄과 마그네슘 첨가가 용융아연 도금강판 도금층의 미세조직과 경도에 미치는 영향)

  • Yoonje Sung;Donggyu Kim;Jungi Seo;Kyunghyun Han;Beomki Hong;Kangmin Kim;Seounguk Heo;Seonghyun Park;Jae-Taek Im;Seung Bae Son;Seok-Jae Lee;Jae-Gil Jung
    • Journal of the Korean Society for Heat Treatment
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    • v.36 no.4
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    • pp.198-205
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    • 2023
  • We investigated the effects of Al and Mg on the microstructure and hardness of the coating layer of galvanized steel sheets, by thermodynamic calculations, X-ray diffraction, scanning electron microscopy, and Vickers hardness tests of Zn-0.2Al, Zn-6Al-2Mg, and Zn-10Al-5Mg coating layers. Regardless of the alloy composition of the galvanizing bath, a Fe-Al layer was observed between the coating layer and steel sheet. The Zn-0.2Al coating layer consists of major h.c.p. Zn phase and minor f.c.c. Al phase. The fraction of f.c.c. Al phase (containing a significant amount of Zn) of the coating layer increases with increasing the chemical composition of Al of the galvanizing bath. The h.c.p. MgZn2 phase was formed in the Al/Mg-containing Zn-6Al-2Mg and Zn-10Al-5Mg coating layers, forming Zn-Al-MgZn2 eutectic microstructure. The primary MgZn2 phase was additionally formed in the Zn-10Al-5Mg coating layers containing high concentrations of Al and Mg. The Vickers hardness values of Zn-0.2Al, Zn-6Al-2Mg, and Zn-10Al-5Mg coating layers were 59.1 ± 1.2 HV, 161.2 ± 5.7 HV, and 215.5 ± 40.3 HV, respectively. The addition of Al and Mg increased the hardness of the coating layer by increasing the fraction of the Al phase (containing Zn) and MgZn2 intermetallic compound, which were harder than the Zn phase.

Improvement of Corrosion Resistance by Mg Films Deposited on Hot Dip Aluminized Steel using a Sputtering Method (용융알루미늄 도금 강판 상에 스퍼터링법으로 형성된 마그네슘 코팅막에 의한 내식성 향상)

  • Park, ae-Hyeok;Kim, Soon-Ho;Jeong, Jae-In;Yang, Ji-Hoon;Lee, Kyung-Hwang;Lee, Myeong-Hoon
    • Journal of the Korean institute of surface engineering
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    • v.51 no.4
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    • pp.224-230
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    • 2018
  • In this study, Mg films were prepared on hot dip aluminized steel (HDA) by using a sputtering method as a high corrosion resistance coating. The corrosion resistance of the Mg films was improved by controlling the morphology and the crystal structure of films by adjusting the Ar gas pressure during the coating process. Anodic polarization measurement results confirm that the corrosion resistance of the Mg films was affected by surface morphology and crystal structure. The corrosion resistance of the Mg coated HDA specimen increased with decreasing crystal size of the Mg coating and it was also improved by forming a film with denser morphology. The crystal structure oriented at Mg(101) plane showed the best corrosion resistance among crystal planes of the Mg metals, which is attributed to its relatively low surface energy. Neutral salt spray test confirmed that corrosion resistance of HDA can be greatly improved by Mg coating, which is superior to that of HDG (hot dip galvanized steel). The reason for the improvement of the corrosion resistance of Mg films on hot dip aluminized steel was due to the barrier effect by the Mg corrosion products formed by the corrosion of the Mg coating layer.

The Effect of Tool Geometry on the Mechanical Properties in a Friction Stir Welded Lap Joint between an Al Alloy and Zn-coated Steel (알루미늄 합금과 아연도금강판의 이종 겹치기 마찰교반접합에서 기계적성질에 미치는 Tool Geometry의 영향)

  • Kim, Nam-Kyu;Kim, Byung-Chul;Jung, Byung-Hoon;Song, Sang-Woo;Nakata, K.;Kang, Chung-Yun
    • Korean Journal of Metals and Materials
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    • v.48 no.6
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    • pp.533-542
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    • 2010
  • The specific motivation for joining an Al alloy and Zn-coated steel arises from the need to save fuel consumption by weight reduction and to enhance the durability of vehicle structures in the automobile industry. In this study, the lap joining A6K31 Al alloy (top) and SGARC340 Zn-coated steel (bottom) sheets with a thickness of 1.0 mm and 0.8 mm, respectively, was carried out using the friction stir weld (FSW) technique. The probe of a tool did not contact the surface of the lower Zn-coated steel sheet. The friction stir welding was carried out at rotation speeds of 1500 rpm and travel speeds of 80~200 mm/min. The effects of tool geometry and welding speed on the mechanical properties and the structure of a joint were investigated. The tensile properties for the joints welded with a larger tool were better than those for the joints done with a smaller tool. A good correlation between the tensile load and area of the welded region were observed. The bond strength using a larger tool (M4 and M3) decreased with an increase in welding speed. Most fractures occurred along the interface between the Zn-coated steel and the Al alloy. However, in certain conditions with a lower welding speed, fractures occurred at the A6K31 Al alloy.

Optimization of Resistance Spot Weld Condition for Single Lap Joint of Hot Stamped 22MnB5 by Taking Heating Temperature and Heating Time into Consideration (핫스템핑 공정에서 가열온도 및 유지시간을 고려한 22MnB5의 단일겹치기 저항 점용접 조건 최적화)

  • Choi, Hong-Seok;Kim, Byung-Min;Park, Geun-Hwan;Lim, Woo-Seung;Lee, Sun-Bong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.10
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    • pp.1367-1375
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    • 2010
  • In this study, optimization of the process parameters of the resistance spot welding of a sheet of aluminum-coated boron alloyed steel, 22MnB5, used in hot stamping has been performed by a Taguchi method to increase the strength of the weld joint. The process parameters selected were current, electrode force, and weld time. The heating temperature and heating time of 22MnB5 are considered to be noise factors. It was known that the variation in the thickness of the intermetallic compound layer between the aluminum-coated layer and the substrate, which influences on the formation of nugget, was generated due to the difference of diffusion reaction according to heating conditions. From the results of spot weld experiment, the optimum weld condition was determined to be when the current, electrode force, and weld time were 8kA, 4kN, and 18 cycles, respectively. The result of a test performed to verify the optimized weld condition showed that the tensile strength of the weld joint was over 32kN, which is considerably higher than the required strength, i.e., 23kN.