US 6,585,834 B1Granted

Method for performing a heat treatment of metallic rings, and bearing ring thus obtained

AssigneeSKF Engineering and Research Centre B.V.

InventorsHendrikus Jan Kapaan, Cornelis Noorlander, Jan Thure Slycke, Mats Johan Persson, Barbara Lynne Tozier

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Abstract

A method of performing a heat treatment on steel rings, in particular for bearings, whereby the outer surface and inner surface of a preheated ring are exposed to different flows of a cooling medium such that the regions of the ring adjacent those surfaces are subjected to different cooling processes. The flow supply of the cooling medium is controlled in such a way that a desired internal stress pattern is obtained in the ring. The cooling medium includes of a combination of liquid and gas. An apparatus for performing a heat treatment on steel rings includes a support means for a ring to be treated; first and second supply means for supplying a spray or mist of a liquid, gas or combination thereof to the outer surface or inner surface of the ring, control means for controlling the supply of the spray or mist is also disclosed.

Claims13

Dependent claims

Method for performing a heat treatment on steel rings, comprising

1) exposing the outer surface and the inner surface of a preheated ring to different flows of a cooling medium, consisting of a combination of liquid and gas independently controlled, such that the regions of those surfaces are subjected to different cooling processes;
2) controlling the flow supply of the cooling medium in such a way that a desired internal stress pattern is obtained in said ring by controlling the propagation of phase transformation from austenite to martensite or bainite material structure;
3) clamping the ring in an axial direction in its inner diameters;
4) controlling the clamping force in such a way that out-of-roundness as a result of the cooling processes is kept to a minimum;
and
5) controlling the clamping force exerted in axial direction in relation to the temperature drop of the ring to generally below the martensite transition temperature.

3 more elements

Dependencies are inferred from the claim text.