I've done this successfully. The information aboveis pretty accurate. There is a high probability that the spring steel is 1095 plain carbon and works at the colors/temperatures stated. Be sure to check for a crack asthis is frequently a cause for weakening. Otherwise, it should be quite repairable.
Note for those interested in working steel. The hardening process adds little to the stiffness of the spring. What hardening does is to allow the spring to be compressed past the point where an unhardened piece of steel of the same dimensions would be permanently deformed (plastic deformation). Tempering extends the amount a hardened steel spring can be deflected without breaking (brittleness). A properly designed, made, hardened,and tempered spring can be fully compressed without damage. Consider the number of times an engine valve spring is cycled without loss of performance. And, this after being left compressed for long times.
