actually, only the mark one and two were made of iron. The rest were made of a titanium-gold alloy, with mark 85 being made of a fictional metal called vibranium.
IRON MAN; STEEL DUDE; MINERAL INDIVIDUAL; MASCULINE MEMBER OF THE SPECIES HOMO SAPIENS WITHIN AN EXOSKELETON PARTIALLY CONSISTING OF THE ELEMENT WITH THE ATOMIC NUMBER OF 26 IN THE PERIODIC TABLE