METHOD OF SPRING RECOVERY Russian patent published in 2011 - IPC C21D9/02 C21D1/78 B23P6/00 

FIELD: process engineering.

SUBSTANCE: spring is, first, subjected to setting or annealing and, then, expanded with pitch exceeding that of finished spring. Heat treatment and shot-blast hardening are performed. Spring is pressed by axial load making (10÷300)F"з", where F"з" is spring force at maximum strain. Then, it is pressed by load increased proportional to relation between required setting to that caused by first loading. Note here that loads may be vibrational. Spring reached required height, no repeated pressing is required. In case there are increased requirements to spring force parametres, spring is trimmed again.

EFFECT: higher spring quality and complete recovery.

4 cl