The lip ring on an oxygen steelmaking converter is detachably connected to the top cone of the converter to permit the lip ring to be removed from the top cone when the former becomes damaged, as during deskulling operations. The connection between the lip ring and the top cone is made by swing bolts that are pivotally mounted to the top cone and the flange interface that effects the connection between the lip ring and the top cone is conically formed to eliminate the development of shear stresses in the bolts such that smaller and fewer bolts can be employed to reduce the costs attendant with, and the time required for, replacement of the lip ring.