Car hinges manufacturing process

I'm doing a research on US car hinges manufacturing process, for doors, hoods and lift gates. I'm trying to assess what process is used by car makers. Wheter their hinges are made with stamped, profilled or forged components. Second part of my research is to understand why is each technology chosen vs. another.
Thank you for any help you can give me, as I live in France and therefore I have no easy access to american cars!