Although steel has been around since ancient times, at the advent of the industrial revolution, the quality of steel made a sharp jump. Steel prior to this era uses the same stats as iron due to its poorer quality.
Armour Defence Bonus: : +2
Density Multiplier : 1x
Cost: $10/kg. Any item previously made out of iron is assumed to be made out of Steel in the modern era, and generally has no price increase.