What cannonballs can tell us about cast iron production: evidence from mid-18th to early 19th centuries European warships

CIARLO, NICOLÁS C.; DE ROSA, HORACIO; LÓPEZ, ARIEL; PIANETTI, MERCEDES

Salisbury

Congreso; HMS Annual Conference: Metallurgy in Warfare - A Spur to Innovation and Development; 2014

Historical Metallurgy Society

The ordnance of early Modern main maritime powers (i.e. Great Britain, France, and Spain) played an important role in conflicts for supremacy of the seas. Within this context, the obtention of cannons and cannonballs, along with other manufactures destined to naval construction and equipment, demanded much of the iron production of the time. Iron ordnance received special attention and capital investment, and was subjected to diverse innovation processes in manufacturing techniques and materials, aiming to improve their efficiency. As for cannonballs, their making did not require the same care and attention as cannons, given the function to which they were destined. In turn, the use of poor quality iron ―obtained in the first blast furnaces castings― seems to have been common practice for ammunition production in some foundries. It is likely that cannonballs quality was markedly heterogeneous. In this regard, the microstructure in them exhibited can be considered as representative of the metallurgical characteristics of the cast iron production in this period. This study presents the characterization results of an array of iron projectiles recovered from some mid-18th to early 19th centuries European warships. Based on data obtained using Light Microscopy (LM), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectrometry (EDXRS), a comparative analysis was performed, in order to clarify the technological differences and similarities present in the projectiles belonging to those ships.