fastening vs soldering

fastening and soldering both are nouns.

Word	Noun	Adjective	Verb	Adverb
fastening	Yes	No	No	No
soldering	Yes	No	No	No

As nouns, soldering is a hyponym of fastening; that is, soldering is a word with a more specific, narrower meaning than fastening:

Other hyponyms of fastening include bonding, doweling, earthing, grounding, linkage, ligature, tying, welding, fixation.

fastening (noun)	soldering (noun)
the act of fastening things together	fastening firmly together
restraint that attaches to something or holds something in place