I asked a similar question a while back Best main campaign area for farming iron bits?
Only answer I got so far was Tomb of the Eldritch Sun. It is effective, but not as effective as the Fort Ikon Armory. So if you want to make a quick buck without much trouble, clear the armory a few times.
Also don’t stash epic items, keep one of each and sell the rest, thats a good amount of iron as well.