Patent ID: 6585834
Filing Date: 2003-07-01
Classification: C21D,F16C,Y10S

Abstract:
Method for performing a heat treatment on steel rings, comprising1) 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.