Thermal properties characterization of the bronze casting moulds

The manufacture and use of bronze ritual vessels, as far back as the second and the first millennium BC, is an essential tool in maintaining social order and political structure in China’s Shang and Zhou periods, yet the casting techniques that made them have not been well discussed. The core issue is the manufacturing and use of clay moulds. Not only their design and positioning, archaeological studies show that their material property is also a key to the success of casting such products. The present work, among a series research, is mainly focused on the thermal property analysis of the ancient bronze casting moulds and two other contemporary moulds for comparison. Thermal diffusivity is measured with pulsed thermography as a non-destructive method. The results prove that the thermal diffusivity of ancient bronze casting moulds are relatively low which allows liquid bronze to flow for an extended duration, filling all fine patterns and corners. The difference between the three types of moulds are discussed.