Projecting edge (6)
'projecting edge' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for brim that I've seen before include "The edge of a cup or glass" , "Cup's lip" , "Projecting edge of hat" , "Lip of bowl, cup etc" , "Edge or rim" .)
(Other definitions for flange that I've seen before include "wider opening" , "Raised edge of a wheel" , "Flat outer face of rolled-steel joist" , "Projecting (steel) collar" , "Rim (on wheel)" .)