Which countries produced the best iron and armor

Who produced the best iron and armor for ironclad-era warships?

Britain and Germany are favored, with American and Spanish work also credited; quality depends on refining and alloying, and the ranking changes over time.

British and German makers are favored in this comparison of early naval iron, with American and Spanish production also receiving credit. The ranking depends on the material available and how it is purified and manufactured. Armstrong and American producers are later judged capable of improving on the combinations used with Krupp's steelmaking method. Useful naval metal also depends on controlled alloying: pure iron is too malleable for many structural purposes. A national label or the word 'iron' therefore gives little information about the actual material's properties.