Patent ID: 7744707

Claim:
A method for deep cryogenic tempering of metallic brake rotors, the method comprising the steps of: (a) determining a mass and cross sectional area of the brake rotors; (b) placing the brake rotors at a temperature within a cryogenic processing chamber; (c) cooling the brake rotors at a descent rate, the descent rate being a function of the mass and cross sectional area of the brake rotors, until the temperature of the brake rotors is approximately −300° F., the cooling accomplished by introducing gaseous nitrogen into the cryogenic processing chamber; (d) maintaining the brake rotors temperature at −300° F. for a stay time, the stay time being a function of the mass and the cross sectional area of the brake rotors; (e) raising the temperature of the brake rotors to approximately 300° F. at an ascent rate, the ascent rate being a function of the mass and the cross sectional area of the brake rotors; (f) maintaining the temperature of the brake rotors at 300° F. for a post temper time; (g) lowering the temperature of the brake rotors to room temperature at a cool down rate; (h) raising the temperature of the brake rotors to approximately 300° F. at an ascent rate; (i) maintaining the temperature of the brake rotors at 300° F. for a post temper time; and (j) lowering the temperature of the brake rotors to room temperature at a cool down rate.