set aflame vs set on fire

set aflame and set on fire both are verbs.

Word	Noun	Adjective	Verb	Adverb
set aflame	No	No	Yes	No
set on fire	No	No	Yes	No

As verbs, set aflame and set on fire are synonyms defined as:

Other synonyms of set aflame include set ablaze, set afire.

set aflame (verb)	set on fire (verb)
set fire to; cause to start burning	set fire to; cause to start burning