Patent ID: 8091239

Claim:
A method for producing a bearing ring for large-size rolling bearings comprising at least one race with a hardened peripheral layer, wherein the peripheral layer to be hardened is exposed to the electric field of an inductor in order to be heated and is then quenched, the method comprising the steps of: (a) at the beginning of hardening, arranging at least two inductors above a joint zone of a annular race to be hardened and heating the peripheral layer of said annular race at or adjacent to said joint zone to a hardening temperature, said joint zone defining a point of departure of said two inductors; (b) for heating of a subsequent central zone, moving the inductors in opposite directions along the annular race, wherein the zone lying opposite to said point of departure is already heated by an additional inductor during heating of the joint zone at the point of departure and/or the subsequent central zone; (c) after covering a distance in said step of moving, turning on sprinklers directed onto heated peripheral layers and these layers are quenched, proceeding from the center of the joint zone heated at the beginning of hardening; (d) moving the inductors and sprinklers continually on their ring halves until the inductors and sprinklers coincide again at a zone lying opposite to the point of departure and again form a joint heating zone there; (e) after reaching the required hardening temperature of the zone lying opposite to the point of departure, lifting both inductors from the surface of the race; and (f) directing the sprinklers onto the zone lying opposite to the point of departure.