METHOD OF PRODUCING SPRINGS WITH CONTROLLED FINE NANOSTRUCTURE Russian patent published in 2017 - IPC B21F35/00 B82B3/00 

FIELD: machine building.

SUBSTANCE: invention relates to machine building and can be used for production of springs from steel by hot winding. Method comprises heating a billet to a temperature above the point of AC₃, maintaining the billet at the temperature above the point of AC₃, winding the billet into a spiral at the temperature above the point of AC₃, cooling the spiral down to the temperature of martensitic transformation and tempering. Heating, maintaining and winding the billet is performed within given time interval Δt, which provides obtaining a spring structure with the value of a martensite link within 100–300 nm. Cooling the spring is carried out at a rate higher than or equal to the critical cooling rate.

EFFECT: higher relaxation resistance and cyclic durability of springs.

5 cl, 1 dwg