Element used in steels (9)
I believe the answer is:
manganese
'element used in steels' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for manganese that I've seen before include "steel component" , "Metallic element, Mn" , "Metal used in some steels" , "Metallic element used in steels" , "Hard grey metal, Mn" .)