Metallurigical Analysis of Third to Fifth Century Swords with Ring Pommels Excavated in the Asan-Cheonan Region

Abstract

This study conducts a metallurgical analysis of three swords with ring pommels (Hwandusword) manufactured during the Proto–Three Kingdoms period and the Baekje period and excavatedfrom the Asan and Cheonan. Specifically, we carried out analyses based on a metallurgical microscope,scanning electron microscopy with energy dispersive spectroscopy. the swords were made of bloomeryiron produced through direct smelting and formed by hammering hypoeutectoid steel. It was alsoconfirmed that other heat treatment techniques than shaping were not applied to them. In addition, allof them have a high carbon content and the crystal grains are well refined, so it is believed that thehardness and strength are high. Moreover, the analytic results of nonmetallic inclusions, No.2 swordshave glassy slag and the others verified the existence of fayalite and wüstite on the glassy matrix. And a high Ca content overall. The results of comparing the swords with other swords with ringpommels excavated from the corresponding region indicated that heat treatment techniques were notapplied to these artifacts despite the existence of such techniques. Thus, we analyze that the studysubjects were produced as ceremonial items rather than weapons. Furthermore, the calculation resultsof ratios, such as CaO/SiO2 and (Al2O3/SiO2)/(CaO/SiO2), indicate that the study subjects were producedbased on a similar smelting processing system. Based on the analytic results, this study also suggestsa possibility of the addition of slag generation agents or the use of iron ores with a high Ca content.