Talk:Rhino (Warframe)/@comment-202.158.84.135-20130926025052/@comment-121.44.205.254-20130927132133

Steel fiber only affects health damage as a reduction sadly, at this point in the game its one of the most useless mods. Maybe one day they will let it affect shields then it may be useful in some way.

To answer your actual question tho, no it doesn't affect Iron Skin although Focus adds extra damage absorb to Iron Skin.