Patent ID: 6458226
Filing Date: 2002-10-01
Classification: C21D,Y02P,Y10S

Abstract:
Process for thermomechanical treatment of steel for torsionally-strained spring elements, comprising the steps of:heating an initial material with a heating rate of at least 50 K/s to a temperature above the recrystallization temperature of the initial material; austenitizing the initial material and forming the heated initial material into a formed product in a manner and at a temperature producing recrystallization of the austenite, said forming being performed in at least two forming passes, each of which is performed at a temperature above the recrystallization temperature so as to increase strength and toughness properties in a strain direction of torsionally-strained spring elements produced with the formed product; and quenching the recrystallized austenite of the formed product to below the martensite temperature to martensite and then performing tempering; wherein the formed product is austenitized at least once more after said quenching, and then, quenching performed again.