The present disclosure includes a differential heat treatment method for a forming roller including an outer circumferential surface heat treatment step for heating the outer circumferential surfaces of roller units. The method may additionally include a first natural cooling step for naturally cooling until the surface temperature reaches 100-150 C., an inner circumferential surface heat treatment step for heating the inner circumferential surfaces of the roller units. The method may additionally include a second cooling step for naturally cooling until the roller units reach a room temperature state after the inner circumferential heat treatment. Further, the method may include an inspection and release step for inspecting the hardness of the outer circumferential surface and the inner circumferential surface after the second cooling and releasing when the hardness is within an error range.

A method for producing a rolling bearing component includes providing a rolling bearing component formed from a rolling bearing steel, heating the rolling bearing component to form an austenitic microstructure, and cooling the rolling bearing component in a warm salt bath to a temperature below a martensite start temperature of the rolling bearing steel. The rolling bearing component has a wall thickness or a diameter of at least 85 mm at at least one point and includes a martensitic microstructure in an edge layer region and a microstructure consisting of pearlite or upper bainite in a core region after the cooling. A rolling bearing component produced by the method and a rolling bearing comprising the rolling bearing component are also disclosed.

A method for producing a rolling bearing component includes providing a rolling bearing component formed from a rolling bearing steel, heating the rolling bearing component to form an austenitic microstructure, and cooling the rolling bearing component in a warm salt bath to a temperature below a martensite start temperature of the rolling bearing steel. The rolling bearing component has a wall thickness or a diameter of at least 85 mm at at least one point and includes a martensitic microstructure in an edge layer region and a microstructure consisting of pearlite or upper bainite in a core region after the cooling. A rolling bearing component produced by the method and a rolling bearing comprising the rolling bearing component are also disclosed.