ΔE 7.4, close: similar, with a visible difference side by side. Steel Blue is a little darker than Thunderhawk Blue.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Steel Blue is a little darker than Thunderhawk Blue.
The same difference applies the other way round: Thunderhawk Blue is a little lighter.
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 Thunderhawk Blue on the colour wheel See Steel Blue on the colour wheel
All matches: Thunderhawk Blue equivalents · Steel Blue equivalents