울산 하대고분군 출토 유견철부의 공부 결합기법과 재질 특성 분석

Abstract

This study intends to research on metallurgical characteristics and manufacturing techniques of the fan-shaped iron axe and forged iron axe excavated from ancient tombs in Hadae, Ulsan conducting the non-destructive testing and metallographical analysis. Based on the observation of internal structures, it was identified the heads of fan-shaped axes with the axe cheek and the axe eye which is the hole where the haft is mounted were produced by the combination technique manufacturing the axe cheek with one material and then connecting it with the axe eye while the heads of forged iron axes were produced by the single-piece technique manufacturing the axe head as a single piece with one material and then folding it to make the axe eye. The results of metallographical analysis confirmed that the manufacturing techniques of fan-shaped axe shows the boundary of microstructure between the surface and the inside due to de-carburization. One of these fan-shaped axe was confirmed the oxide scale that occurs when forging welding, so it was manufactured by forge welding with eutectoid steel and pure iron. The three of forged iron axe were manufactured by forging from pure iron, which had the low carbon content. Also, according to the required parts, additional processes were partially carried out. The components of nonmetallic inclusion contained the microstructure of iron axe shows wüstite commonly. From fayalite or glassy slag found in the iron axe, it is judged that axes were manufactured with iron bloom by means of the low temperature reduction process of solid. As a result, it was identified that in the case of the fan-shaped axes and forged iron axes with different form excavated from ancient tombs in Hadae, Ulsan, the manufacturing techniques easy to make each shape were applied and material supplied for the production was identical.