Abstract
Pre-industrial crucible steel ingots, produced in both Central and South Asia, are an important class of iron-carbon alloys. Their microstructure reflects their formation from a liquid alloy at a carbon content of 1.0–2.5wt%, which is higher than most mild steels but lower than most cast irons. This article introduces a tool to quantify the carbon content of such alloys based on an operator-supervised image analysis which determines the relative proportions of austenite/pearlite and cementite, respectively, from high-contrast back-scatter electron images of unetched samples. Using examples from a recently discovered hoard of crucible steel ingots in Telangana, south-central India, we demonstrate the capabilities of the tool and test its usefulness. The main benefit is in improving accuracy and precision in metallography-based carbon content determination in such alloys by reducing the uncertainty in area estimation in complex microstructures based on visual impression alone.
Publisher
The Historical Metallurgy Society Ltd
Subject
History and Philosophy of Science,Metals and Alloys,Archeology
Reference13 articles.
1. Alaa N and Abidne El I Z 2021, Image processing with Python: An introduction. LAMAI Laboratory FST, Cadi Ayyad University (Marrakech).
2. Czarski A, Skowronek T, and Matusiewicz P 2015, ‘Stability of a lamellar structure – effect of the true interlamellar spacing on the durability of a pearlite colony’, Archives of Metallurgy and Materials 60, 2499–2503. https://doi.org/10.1515/amm-2015-0405.
3. Das G 1999, ‘Image analysis in quantitative metallography’ in G Sridhar, S Ghosh Chowdhuny and N G Goswami (eds), Materials characterization techniques, principles and applications (NML Jamshedpur), 135–150.
4. Doane D and Seward LE 2011, ‘Measuring skewness: A forgotten statistic?’ Journal of Statistics Education 19(2). https://doi.org/10.1080/10691898.2011.11889611.
5. Ferrer-Eres M A, Peris-Vicente J, Valle-Algarra F M, Gimeno-Adelantado J V, Sanchez-Ramos S, and Soriano-Pinol M D 2010, ‘Archaeopolymetallurgical study of materials from an Iberian culture site in Spain by scanning electron microscopy with X-ray microanalysis, chemometrics and image analysis,’ Microchemical Journal 95, 298–305. https://doi.org/10.1016/j.microc.2010.01.003.