Iron stories. The descriptions of the 18th century. Part 11: On the various conceptions of cast-iron conversion in the finery hearth. The descriptions of iron metallurgy by the 18th-century scientists are exposed and discussed, through cast iron production and refining into wrought iron or steel. This second part shows the selection criteria between white and grey cast iron and the refining control differences, as a function of the aim of die conversion, either into wrought iron or into steel. The questions concern (i) the differences between conversion into iron and steel, (ii) the behaviour of white and grey cast iron during fining, and (iii) the description of the conversion of cast iron when they are supposed to contain oxygen. To cite this article: J. Le Coze, C R. Chimie 11 (2008). (C) 2008 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.