Material characterization of forged bronzes from ancient China (c. 11th-2nd century BCE) reveals development of the non-mainstream metalworking technique in Chinese bronze production

Although ceramic piece-mould casting was the dominant metalworking technique in the Chinese Bronze Age (c. 2100-221 BCE), the forging technique was also employed by craftsmen to pursue lightweight bronzes with thin walls and high hardness. However, compared to the ceramic piece-mould casting technique, research on forging technology is relatively limited. In this research, 48 sheet metal fragments of Chinese bronzes from different regions and periods (from the Zhou to Han dynasties) across China were analyzed by metallography, SEM-EDS, and hardness testing. The results show that craftsmen had a profound understanding of copper alloy properties and were able to produce thin-walled, functional artifacts by forging cast blanks with appropriate alloy compositions. With the development of forging technology and political changes, the types of forged thin-walled bronzes became more diverse, and their consumers expanded from the elite to civilians. This study not only reveals the material characterization of forged bronzes, but also elucidates the historical trajectories of forging technology and the multifaceted interplay between cultural influence, aesthetic pursuits and technological advancement in the development of forging techniques in ancient China.