The early cast iron processing technology in central China: scientific analysis on the iron artefacts from Ouerping site, Shanxi Province, ca.400BC-200BC

Ouerping site, an important excavation archaeological site unearthed in 2017 in Jinzhong city, Shanxi province, China, dates back to the Warring States period. Metallographic, scanning electron microscopy coupled with energy-dispersive spectroscopy and energy dispersion-type X-ray fluorescence spectrometer analysis of the site’s iron artefacts revealed that they were made of two types of materials: hypereutectic white iron and cast iron annealed products. Among them, the cast iron is hypereutectic white iron, and the annealed products include decarburized cast iron, cast iron decarburized steel (wrought iron) and ductile cast iron. For the first time, ductile cast iron products were discovered in Shanxi. According to the age of each layer of the site, the craftsman has mastered the cast iron annealed and decarbonization technology since the middle of the Warring States period, and applied it to tools and weapons. Combined with the iron artefacts storage of the site and the construction of building foundations, the iron solid-decarburised production has reached a certain scale, played an important role in social and economic development. The site is rich in solid-decarburised products and has strong time continuity, and the study of them not only reveals the technical connotation of iron production in this area, but also provides important materials for studying the development of cast iron Processing technology and social development in Shanxi and even in ancient China.