Wasn't sure whether to post this on ELU or here, but thought I would have better luck here. Anyway Merriam Webster defines a Stud Bolt as
a bolt with threads on both ends designed to be screwed permanently into a fixed part at one end and to receive a nut on the other.
Is the first part of the definition - screwed permanently into a fixed part - always true for a stud bolt? If so, what do you call the threaded rod that fully penetrates two parts and is attached with a nut on both ends like you would see for piping flanges?