In England From 1760 to ~1770, with the use of coke (coal) in the manufacture of ductile cast iron. Always by direct casting in the blast furnace. Iron cannons were cast near 1770 to 1775 in England and near 1780 to 1790 in France and Belgium.
(I did find this in the history of the frigate Hermione 1779 to 1793)...
If that can help...