steel plant vs steel factory

steel plant and steel factory both are nouns.

Word	Noun	Adjective	Verb	Adverb
steel plant	Yes	No	No	No
steel factory	Yes	No	No	No

As nouns, steel plant and steel factory are synonyms defined as:

Other synonyms of steel plant include steel mill, steelworks.

steel plant (noun)	steel factory (noun)
a factory where steel is made	a factory where steel is made