Most senior figure in steel manufacture (6)
I believe the answer is:
eldest
'most senior' is the definition.
(I've seen this in another clue)
'figure in steel manufacture' is the wordplay.
'figure' becomes 'd' (I can't justify this - if you can you should give a lot more credence to this answer).
'in' is an insertion indicator.
'manufacture' indicates an anagram.
'steel' with letters rearranged gives 'elest'.
'd' placed inside 'elest' is 'ELDEST'.
Can you help me to learn more?
(Other definitions for eldest that I've seen before include "The oldest of three or more" , "Most senior of a group" , "Most senior in age" , "Most aged" , "Firstborn; led set (anag.)" .)