• Title/Summary/Keyword: WA(White Alumina)

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Magnetic Abrasive Polishing for Internal Face of STS Tube using Sludge Abrasive Grain

  • Kim, Hee-Nam;Soh, Dea-Wha;Hong, Sang-Jeen;Lee, Byung-Woo
    • Transactions on Electrical and Electronic Materials
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    • v.6 no.3
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    • pp.128-132
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    • 2005
  • In this paper, we have investigated the characteristics of the magnetic abrasive using sludge on polishing of internal finishing of seamless stainless steel (STS304) tube applying magnetic abrasive polishing. Either white alumina (WA) or green carborundum (GC) grain was used to resin sludge at a low temperature, and the sludge of magnetic abrasive powder was synthesized and crushed into 200 meshes. Surface roughness was measured before and after polishing, and more than $40\%$ of improvement of surface roughness was achieved when WA grain was used under a specific condition. Even though some degree of surface roughness due to deeper scratches still exist, but the result showed a prospective magnetic abrasive polishing using sludge with WA or GC grains.

Magnetic Abrasive Polishing for Internal Face of Stainless Steel Tube using Sludge Abrasive Grain

  • Kim, Hee-Nam;Soh, Dea-Wha;Hong, Sang-Jeen
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.77-80
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    • 2004
  • In this paper, we have investigated the characteristics of the magnetic abrasive using sludge on polishing of internal finishing of seamless stainless steel (STS304) tube applying magnetic abrasive polishing. Either white alumina (WA) or green carborundum (GC) grain was used to resin sludge at a low temperature, and the sludge of magnetic abrasive powder was synthesized and crushed into 200 meshes. Surface roughness was measured before and after polishing, and more than 40% of improvement of surface roughness was achieved when WA grain was used under a specific condition. Even though some degree of surface roughness due to deeper scratches still exist, but the result showed a prospective magnetic abrasive polishing using sludge with WA or GC grains.

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Development of the Magnetic Abrasive Using Worthless Mineral (폐광물을 이용한 자기 연마재 개발)

  • Kim, Hee-Nam;Kim, Dong-Wook
    • Journal of the Speleological Society of Korea
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    • no.70
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    • pp.45-50
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    • 2006
  • The magnetic polishing is the useful method to finish using magnetic power of magnet. This method is one of precision polishing techniques and has an aim of the clean technology using for the pure of gas and inside of the clean pipe for transportation. The magnetic abrasive polishing method is not so common for machine that it is not spreaded widely. There are rarely researcher in this field because of non-effectiveness of magnetic abrasive. Therefore, in this paper deals with development of the magnetic abrasive using worthless mineral. In this development, abrasive grain WA and GC used to resin bond fabricated low temperature. And magnetic material was fabricated from the worthless mineral which were closed into 200 mesh grit type. The XRD analysis result show that only WA and GC abrasive and worthless mineral crystal peaks detected which explains resin bond was not any more chemical reaction. From SEM analysis it is found that WA and GC abrasive and worthless mineral were strong bonding with each other by bond.

Development of The Magnetic Abrasive Using Barium Ferrite (Ba-Ferrite를 이용한 자기 연마재 개발)

  • 김희남;송승기;정윤중;윤여권;김희원;조상원;심재환
    • Journal of the Korean Society of Safety
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    • v.18 no.2
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    • pp.46-49
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    • 2003
  • The magnetic polishing is the useful method to finish some machinery fabrications by using magnetic power. This method is one of the precision techniques and has m aim for clean technology in the transportation of the pure gas in the clean pipes. The magnetic abrasive polishing method is not so common in the field of machine that it is not known to widely. There are rarely researcher in this field because of non-effectiveness of magnetic abrasive. Therefore, in this paper we deals with the development of the magnetic abrasive with the use of Ba-Ferrite. In this development, abrasive grain WA has been made by using the min bond fabricated at low temperature. And magnetic abrasive powder was fabricated from the Ba-Ferrite which was crushed into 200 mesh. The XRD analysis result shows that only WA abrasive and Ba-Ferrite crystal peaks were detected, explaining that resin bond was not any more to contribute chemical reaction. From SEM analysis, we found that WA abrasive and Ba-Ferrite were strongly bonding with each other.

Magnetic Abrasive Polishing for Internal Face of Seamless Stainless Steel Tube Using Sludge Abrasive Grain (슬러지 연마입자를 이용한 이음매 없는 스테인리스강 튜브내면의 자기연마)

  • Kim, Hee-Nam;Yun, Yeo-Kwon;Kim, Sang-Baek;Choi, Hee-Sung
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.6
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    • pp.151-157
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    • 2004
  • In this paper deals with behavior of the magnetic abrasive using sludge on polishing characteristics in a new internal finishing of seamless stainless steel tube applying magnetic abrasive polishing. The magnetic abrasive using sludge-abrasive grain WA and GC used to resin bond fabricated low temperature. And sludge of magnetic abrasive powder fabricated that sludge was crused into 200 mesh. The previous research have made an experiment in the static state the movement of magnetic abrasive grain is nevertheless in the dynamic state. In this paper, We could have investigated into the changes of the movement of magnetic abrasive grain. In reference to this result, we could have made the experiment which is set under the condition of the magnetic flux density, polishing velocity according to the form of magnetic brush.

Development of the Magnetic Abrasive Using Sludge (Sludge를 이용한 자기 연마재 개발)

  • Kim, Hee-Nam;Yun, Yeo-Kwon;Kim, Sang-Baek;Choi, Hee-Sung;Ahn, Hyo-Jong
    • Journal of the Korean Society of Safety
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    • v.19 no.2
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    • pp.6-10
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    • 2004
  • The magnetic polishing is the useful method to finish using magnetic power of magnet. This method is one of precision polishing techniques and has an aim of the clean technology using for the pure of gas and inside of the clean pipe for transportation. The magnetic abrasive polishing method is not so common for machine that it tis not spreaded widely. There are rarely researcher in this field because of non-effectiveness of magnetic abrasive. Therefore, in ths paper deals with development of the magnetic abrasive using sludge. In this development, abrasive grain WA and GC used to resin bond fabricated low temperature. And magnetic material was fabricated from the sludge which were crused into 200 mesh and average diameter ${\o}$1.2mm ball type. The XRD analysis result show that only WA and GC abrasive and sludge crystal peaks detected which explains resin bond was not any more chemical reaction. From SEM analysis it tis found that WA and GC abrasive and sludge were stron bonding with each other by bond.

A Study on alumina Sintering through the Oxidation of AI Powder. (Al 분말의 산화에 의한 $Al_2O_3$ 소결에 관한 연구)

  • 박정현;안주삼;김해두
    • Journal of the Korean Ceramic Society
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    • v.19 no.3
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    • pp.179-186
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    • 1982
  • This research is to aim at the study of sintering mechanism through the observation of microstructure by scanning electron microscopy, after the mixture of 30wt% $Al_2O_3$ (White Alundum) powder is fired in air at the temperature range of 1350~150$0^{\circ}C$ in order to sinter $Al_2O_3$-Al through the oxidation of Al powder. The results obtained in this experiment are as follows: 1. While the compressive strength of $Al_2O_3$(WA) body fired at $1450^{\circ}C$ for 5hrs in air is 150kg/$\textrm{cm}^2$, that of Al-$Al_2O_3$ body fired at 135$0^{\circ}C$, $1400^{\circ}C$ for 5hrs in air is 1100kg/$\textrm{cm}^2$, 1600kg/$\textrm{cm}^2$ respectively, and the higher the firing temperature, the more the compressive strength increases. These results from the sintering effect between $Al_2O_3$(WA) grains and surrounding Al-oxidation layer. 2. While the compressive strength of Al2O3(WA) body fired at 150$0^{\circ}C$ for 5hrs in air is 250kg/$\textrm{cm}^2$, the compressive strength of Al-$Al_2O_3$body fired under the same condition is 2050kg/$\textrm{cm}^2$ and water absorption 9.0%, porosity 23.3%, bulk density 2.60gr/$cm^3$. It is assumed that these results come from not only the grain growth of oxidized Al grains but also the increase of bonding strength between $Al_2O_3$(WA) grains.

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