METHOD FOR MANUFACTURING LARGE-SIZED SPRINGS OF STEEL Russian patent published in 2017 - IPC B21F35/00 C21D9/02 F16F1/06 

FIELD: metallurgy.

SUBSTANCE: method includes heating the bar, winding the spring from the bar onto the mandrel at the heating temperature, turn by turn quenching of the spring at its continuously-consecutive movement on the mandrel and final processing of the spring by releasing. Turn by turn quenching of the springs is carried out with different adjustable cooling rates in the tank with the quench liquid and equipped with a sprayer, which movable mechanism for spring moving is located below the level of the quench liquid. The passage of the spring through the sprayer is carried out at its cooling rate higher than critical, with the provision of accelerated cooling within A₁-M_n temperature range and forced removal of the steam jacket from the inner surface of the spring turns which are in contact with the mandrel. As each spring turn sequentially leaves the action zone of the sprayer device, slow cooling of the spring takes place in the temperature range of the martensitic transformation M_n-M_k and the final quenching of the spring.

EFFECT: increase the strength and service life of the manufactured spring by obtaining a fine-grained metal structure.

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