Metallurgical and Technological Characterization of a Lombard Seax from North Italy

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A metallurgical study of a Renaissance spearhead from northern Italy was performed to provide new deep insights into both smelting and smithing technologies which are involved in the manufacturing process. Optical microscopy observations, Vickers microhardness measurements, and optical emission spectroscopy analyses demonstrated that the spearhead was skillfully assembled and shaped from different steel bars, and a slack-quenching heat treatment was performed on the blade to improve its functionality. The chemistry of a large sample of nonmetallic inclusions was characterized by scanning electron microscopy coupled with X-ray dispersive spectroscopy. A multivariate statistical data treatment based on logistic regression was applied to assess the technological origin of the steel bars. The results allowed to conclude that the spearhead steel was obtained following the indirect steel-making route. The temperatures reached during both smelting and smithing stages were estimated in the FeO–SiO2–CaO system at 1470 °C and 1200 °C, respectively.

Section: Introductionmentioning

confidence: 99%

Archeometallurgical Study of a Renaissance Spearhead from Northern Italy

Merico

Faccoli

Gotti³

et al. 2022

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Analysis of Ancient Slag Inclusion-Metal Systems as a Method to Disclose Processing Thermo-chemical Parameters: The Case Study of a Medieval Lombard Steel Bar from Northern Italy

Merico

Faccoli

Cornacchia

2023

An archaeometallurgical characterization of a VI to VII century Lombard steel bar from Ponte di Val Gabbia I site (northern Italy) was performed to reconstruct its manufacturing process and extract processing thermochemical parameters (i.e., temperature and oxygen chemical potential) from the slag inclusion-metal systems. Metallographic observations by optical microscopy and Vickers microhardness measurements indicated that the steel bar was forged from a heterogeneous steel lump, most probably an iron bloom, which was cooled in the air after the forging process. The chemical composition of non-metallic inclusions was determined by scanning electron microscopy coupled with X-ray dispersive spectroscopy. A multivariate statistical analysis of the smelting-derived non-metallic inclusions chemistry allowed to conclude that the steel bar was obtained by the direct or bloomery method. Under the hypothesis of local near-equilibrium conditions for the slag inclusion-metal systems, a thermodynamic-based strategy was adopted to estimate the firing conditions in the bloomery furnace in terms of both temperature and oxygen chemical potential of the reducing gas atmosphere. In particular, the computed temperatures are in the range of 1003 °C to 1171 °C, whereas the values of oxygen chemical potential vary between − 447.47 and − 385.79 kJ/mol.

Archaeometallurgical Study of a 16th–17th Century “Rapier” Sword Manufactured in Caino (Northern Italy)

Merico,

Faccoli,

Gotti

et al. 2024

A metallurgical study was performed on a 16th–17th century “rapier” sword manufactured in Caino (northern Italy). Metallographic investigations and Vickers microhardness measurements indicate that the rapier was forged by assembling via hammer-welding different hypoeutectoid and near eutectoid steel bars. The rapier blade was heat treated by slack-quenching to increase its hardness, especially near the blade tip, improving the thrusting performance. The chemical composition of slag inclusions was analyzed by scanning electron microscopy coupled with X-ray dispersive spectroscopy. Compositional data of slag inclusions were analyzed by a multivariate statistical strategy aimed to distinguish and classify slag inclusions on the basis of their origin. It was estimated that the temperature reached during the finery and forging processes was at least 1270 °C and 1160 °C, respectively.