I need to source aprox 1000 pieces of hairsprings to vibrate with vintage Oris 671Kif  balance and other calibers of this family,  I know hairspring of same strength were used for most vintage in-house Oris movements. but I can't tell what material/alloy Oris 671kif  hairspring is made from.  Have seen some members here on forum identify alloys as though one is naturally born with such ability to know alloys. not me though, I don't have the slightest idea how you go about identifying alloys