Ironware Manufacturing Techniques of Goguryeo Shown at Large Iron Swords Excavated from Hongryeong-bong Fort 1/2, Boru-gun, Achasan Area, Historic Site No 455

Abstract

A large iron sword refers to a sword used as a weapon and in Korea, it was actually used as one of war weapons since the latter part of the 3rd Century and at the same time as a means to symbolize the status of the bearer. As research on Goguryeo period has been very limited for the scientific analysis due to the nature of the area, this study sought to deal with metallurgical analysis on large iron swords.Methods/Statistical analysis: The study analyzed two pieces of large iron swords excavated from Mount Achasan Fort 1/2 and compared them with metallurgical analysis result of iron artifacts excavated from nearby remains of Achasan Fort 4 and Guui-dong. All of two pieces turned out to be manufactured by forging mold and heat treatment process. Findings: Large iron sword No 1 showed the shape of ferrite crystal grain or pearlite, and given the shape of the structures, it was considered to have been pounded or exposed to heat treatment in relatively low temperatures instead of being cooled down simply by being exposed to outside air. As for Large iron sword No 2, the study found that its main parts had tempered Martensite phase, while its spine had ferrite phase - soft iron structure. So, the study believes that at the time ironware manufacturing technique was used to increase carbon content at any wanted parts through carburizing. Improvements/Applications: Given these iron manufacturing, heat treatment techniques were used at the time, people at Achasan Fort 1/2 presumably had their own iron manufacturing ability.