METHOD OF SPRING RECOVERY Russian patent published in 2011 - IPC B21F35/00 

FIELD: process engineering.

SUBSTANCE: invention relates to plastic metal working and can be used for recovery of springs at diverse enterprises. Proposed method comprises expansion, heating and cooling of springs. Prior to expansion, spring is heated and tempered, and, then, it is expanded with the pitch exceeding that of finished spring. Then, it is thermally treated and shot-blast hardened, or thermally cambered. Now, spring coils are plastically hardened by compressing it at axial load of (10-300)F3, where F3 is spring force at maximum strain.

EFFECT: higher efficiency and quality.

4 cl