Victorians used cast iron widely and foundries like Coalbrookdale and Falkirk are world famous for their high quality.
Salvaged elements like staircase balusters and church floor grilles are widely available.
Modern safety standards sometimes necessitate the removal of these items during conversion work but thoughtful design can make them suitable again as balustrades, security rails or decoration.
There are differences in wrought iron, cast iron and mild steel, the latter being simpler to work with. Cast iron is brittle and hard to weld.
You may need to enlist the skills of a professional metalworker for these the elements.