There's lots of videos of high-speed spring making machines floating around e.g. YouTube, typically taking wire stock of up to a millimeter or so in diameter and producing items which are clearly intended to be flexed repeatedly.
Production obviously takes the stock wire beyond a yield point so that it is permanently deformed, which- if my understanding is correct- would work best if the stock was in an annealed state.
What is the temper state of the wire stock, and do the produced parts need to be heat treated before being put into service?
Alternatively, if these machines are over-stressing steel which is already spring-tempered, is the performance of the resulting parts inferior to springs made out of annealed stock and subsequently tempered?