Steel

Steel is an alloy of iron and carbon. Most swords and armour in early period were not made of steel, but iron, owing to the difficulty of forging steel. Later period smelting techniques were able to produce good quality steel and in large quantities.

In period, Japanese swords are notable for the quality of their steel as it was produced from poor quality ore, as were Damascus and Toledo blades.

Weapons and armour used in the SCA can be made of much higher quality steel than medieval equivalents, since modern manufacturing produces very homgenous steel.

Both steel and iron will form iron oxidize (rust), which weakens the metal as the rust is water soluble and washes the material away exposing more of the original metal to oxidize. For this reason, period armour was often painted or left covered in forgeblack, rather than being polished. If armour was polished, it needed frequent scouring and oiling to maintain it.

Modern stainless steel will rust is left in a pool or water or sweat. Modern galvanized steel turns dark grey or black as the coating oxidises, but doesn't lose any strength as this oxidised coating in insoluble in water.