US 7,744,707 B2Granted

Deep cryogenic tempering of brake components

AssigneeBrian Morrison

InventorRobert Woolley Brunson

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Abstract

A deep cryogenic tempering process for brake components such as rotors and drums is provided, wherein the unique processing profile is dependent on properties of the specific brake components. The process comprises the steps of placing a brake component at a temperature within a cryogenic processing chamber, cooling the brake component at a descent rate until the brake component temperature is approximately −300° F., maintaining the brake component temperature at −300° F. for a stay time, raising the temperature of the brake component to approximately −300° F. at an ascent rate, maintaining the temperature of the brake component at 300° F. for a post temper time, and lowering the temperature of the brake component to room temperature at a cool down rate.

Claims5

Dependent claims

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.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/844,526Filed 27 Apr 2001
Published: US 2002/0179204 A15 Dec 2002
Granted: 29 Jun 2010
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

C21D 1/785
Combined heat-treatments not provided for above: thermocycling
C21D 6/04
Heat treatment of ferrous alloys: hardening by cooling below 0 degrees Celsius
C21D 1/613
Characterised by the quenching agents: gases; Liquefied or solidified normally gaseous material
C21D
Modifying the physical structure of ferrous metals

Family

US 2002/0179204 A1Pre-grant publication · published 5 Dec 2002
US 7,744,707 B2This patent

From the US filing history. Foreign family members aren’t listed.

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