• Title/Summary/Keyword: Ulsan Mine

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Metallic Mineralogical Characteristics of Forged Iron Axe from the Wood-framed Tomb at the Hwangseongdong, Gyeongju, Korea (경주 황성동 목곽묘 출토 단조 철부의 금속광물학적 특성)

  • Kim, Jeong-Hun;Yi, Ki-Wook;Lee, Chan-Hee
    • Journal of the Mineralogical Society of Korea
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    • v.20 no.4
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    • pp.231-245
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    • 2007
  • The forged iron axe of the middle 3rd Century found in the No. 2 wood-framed tomb from the Hwangseongdong site, Gyeongju is rectangular on the plane level. The iron axe shines in met-allic luster, which is light grey with pale creamy tint. The result of X-ray diffraction analysis shows that the axe consists of magnetite and geothite, which can explain why the composition and texture of the original ore has been kept intact. There are fine-grained quartz, calcite, mica, magnetite, amphibole, unknown tungsten minerals, pyroxene and olivine inside the axe. Those must be the impurities that they failed to remove in the thermal treatment process. Generally, the iron axe consists mainly of pearlite texture coexisting ferrite and cementite, and show high carbon contents with homogeneous distribution. It can be interpreted the axe was carburized after the material was made to resemble pure iron. The decarbonization work didn't go well along the process marks. Crude ores of the iron axe are possible utilized by magnetite from the Ulsan mine on the basis of the occurrences and inclusions. It's estimated that the original ore was bloom produced in low-temperature reduction and formed around in $727^{\circ}C$, which is eutetic temperature.