tin plate vs sheet metal

tin plate and sheet metal both are nouns.

Word	Noun	Adjective	Verb	Adverb
tin plate	Yes	No	No	No
sheet metal	Yes	No	No	No

As nouns, sheet metal is a hypernym of tin plate; that is, sheet metal is a word with a broader meaning than tin plate:

tin plate: a thin sheet of metal (iron or steel) coated with tin to prevent rusting; used especially for cans, pots, and tins
sheet metal: sheet of metal formed into a thin plate

tin plate (noun)	sheet metal (noun)
a thin sheet of metal (iron or steel) coated with tin to prevent rusting; used especially for cans, pots, and tins	sheet of metal formed into a thin plate