The project
A tower flange this large would be prohibitively expensive to forge as a solid disc and machine down to a ring — seamless ring rolling starts from a pierced, doughnut-shaped blank and expands it directly to near-final ring dimensions on a ring mill, using far less starting material and producing continuous circumferential grain flow with no weld seam, exactly the property a bolted flange under sustained cyclic wind loading needs most.
The ring was rolled to a generous machining allowance on both faces and the bore, then shipped for outside finish machining and bolt-hole drilling per the tower manufacturer’s own drawing.