8th Experimental Archaeology Conference abstract – Wrona
The carburization of iron objects in a pottery kiln
The Jan Kochanowski University in Kielce, ul. Żeromskiego 5, 25-369 Kielce, Poland
Case-hardening was probably the most common way of iron carburization in ancient and medieval times. The procedure however is highly time and fuel-consuming, as attested by descriptions from Theophilus Presbyter or Giambattista della Porta, is however highly time- and fuel-consuming. But the blacksmith’s hearth is not the only place where this process could be carried out. During long-time observation of firing pottery in an ancient type kiln, the idea arose to try to use this as a carburizing device. Very long periods of firing operation, during which almost half of the time temperature inside kiln achieves about 900°C, create perfect conditions for the conducting of case-hardening process. This paper presents results of a few experiments of iron carburization in a pottery kiln, in both reduction and oxidation atmosphere firing. In the first case, the iron items were placed inside the vessel and covered by charcoal dust and other organic materials which were sources of carbon. In the second experiment, the artifacts were deposited directly in the oven and the carburizing agent was the carbon monoxide gas filling the oven’s chamber. A clue indicating a possibility of using this method in antiquity might be vessel fragments with reduced internal surface, that occur often within the archaeological record.
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