Exploring the manufacturing process of a renaissance breach pike

An archaeometallurgical study of a Renaissance breach pike was performed to elucidate its manufacturing process. Optical microscopy observations and microhardness measurements indicated that the breach pike was forged starting from a heterogeneous steel lump. The microstructural features were compatible with post-forging air cooling. The chemistry of a large set of nonmetallic inclusions was investigated by scanning electron microscopy coupled with X-ray dispersive spectroscopy. Compositional data were analyzed by multivariate statistics to distinguish smelting-related slag inclusions. A logistic regression model indicated that the steel was probably produced by the direct method. The liquidus temperatures of the slag inclusions indicated maximum smelting temperatures in the range of 1200 ◦C to 1300 ◦C. A thermodynamic-based model was adopted to estimate the average smelting conditions in terms of temperature and oxygen chemical potential and investigate the disequilibrium of slag inclusion–metal systems. For low-disequilibrium systems, the computed temperature values range between 1095 ◦C and 1118 ◦C, while the oxygen chemical potentials (μO2) span from −442 to −374 kJ/mol.