rate contract for supply of top and middle flange , rate contract for supply of al flange(top + middle) for 24 months from approval at bhel, bhopal. evaluationshall be doen itemwise. , fully machined unplated top flange (pvn 36) to drg no. 25217001503-002 rev.25 (pitch x shall be informed at the time of po placement). (casting drg. 25217001516-002 rev.07). pvc ratio for aluminium is 1:3.7. base rate of aluminium alloy ingot ia10, as declared by nalco, is rs. 263.65/kg. , fully machined unplated middle flange (pvn 36) to drg no. 25217001595-var. 01, rev.06 (pitch x shall be informed at the time of po placement). (casting drg. 25217001518-003 rev.10). pvc ratio for aluminium is 1:4.6. base rate of aluminium alloy ingot ia10, as declared by nalco, is rs. 263.65/kg.