set on fire vs set aflame

set on fire and set aflame both are verbs.

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

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

Other synonyms of set on fire include set ablaze, set afire.

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