GB1427019A - Ring rolling mill - Google Patents

Abstract

1427019 Rolling rings RHEINSTAHL AG 8 May 1973 [9 May 1972] 21753/73 Heading B3M A ring rolling mill comprises rolls 1 and 2 (Fig. 1) acting on the external and internal surfaces of a workpiece ring 5, and two frusto-conical rolls 3 acting on the end surfaces, the peripheral speeds of the four rolls being maintained equal during rolling. In one form, the speed of one of the two rolls 3 (only one is driven) is controlled in response to both the speed of the driven roll 1 and the position of the ring as detected by sensors 16. If the ring tends to shift laterally during rolling, a differential signal from the two sensors is generated at 18. This causes the speed of the roll 3 to be modified in a sense to return the ring to. its central position. Centering rollers 6, which are moved outwardly on arms 7 as the ring expands, may be used as sensors in place of the sensors 16. Either the rolls 3 or the rolls 1 and 2 may be shifted along the mill frame during rolling, to maintain the axes of the rolls 3 at the centre point 4 of the ring. In another form, Fig. 4, the axial positions of the rolls 3 may be adjusted, rather than their speeds, using an actuator 25. As before, the actuator is operated in response to differential movement of sensor rollers 6, indicating a lateral shift of the ring. This differential movement is detected in a bridge 29 and an error signal is fed to the actuator 25. Simultaneously, as throttle unit 31 associated with the roller which has. been shifted most is controlled such that its throughflow is changed and the roller produces a force on the ring tending to restore it to its central position. A speed control unit 23 acts with a tacho-generator 11 to give initial speed adjustment of the roll drives.