ΔE 13.1, fair: the same colour family, but not a straight swap. Natural Steel is noticeably darker, more saturated than Pig Iron.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Natural Steel is noticeably darker, more saturated than Pig Iron.
The same difference applies the other way round: Pig Iron is noticeably lighter, more muted.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Pig Iron on the colour wheel See Natural Steel on the colour wheel
All matches: Pig Iron equivalents · Natural Steel equivalents