Beam held by iron band finally coming apart (6)
I believe the answer is:
frayed
'apart' is the definition.
Both the answer and definition are adjectives. Perhaps you can see an association between them that I can't see?
'beam held by iron band finally' is the wordplay.
'beam' becomes 'ray' (synonyms).
'held by' indicates putting letters inside.
'iron' becomes 'Fe' (chemical symbol for iron).
'finally' indicates one should take the final letters.
The final letter of 'band' is 'd'.
'ray' placed inside 'fe' is 'fraye'.
'fraye'+'d'='FRAYED'
'coming' is the link.
Can you help me to learn more?
(Other definitions for frayed that I've seen before include "Of garment, worn and with loose threads" , "Threadbare and worn" , "Worn at the edge" , "Ragged at the edges" , "Tattered and threadbare" .)