Method for the thermomechanical treatment of seamless rings produced on radial-axial ring rolling machines

Abstract

A method and a device are provided for the thermomechanical treatment of seamless steel rings produced on radial-axial ring rolling machines, particularly rings of fine grain steel, heat-treatable steel, case hardened steel, or austenitic steel, preferably of steel tower flanges for wind turbine generators. The ring blank is inserted into the ring rolling machine at a temperature in the range of 900° C. to 1150° C. and is rolled to an outer diameter preferably in the range of 0.2 m to 10 m by a hot forming process. The hot ring () is quickly cooled down by a controlled process directly following the rolling, without secondary heating, from a temperature over the conversion temperature in the austenite range to a temperature below 400° C. The device includes a dipping basin filled with cooling liquid () or an unfilled cooling container, and a carrier () that can be lowered with a hoisting device (), the rolled ring () lying on the carrier. Pressure nozzles () are arranged in the dipping basin or the cooling container () on one or several ring lines (), in an equal distribution, for the targeted application of the cooling liquid () onto at least one of the ring-shaped surfaces of the ring (). Measurement of the ring temperature before and/or after the cooldown is carried out, preferably, with a radiation pyrometer.