nominal bore welded fittings Nominal Bore Schedule 10 90 deg weld Elbow to ANSI B16.9 Nominal Bore Schedule 40 90 deg weld Elbow to ANSI B16.9 Nominal Bore Schedule 10 weld Tee to ANSI B16.9 Nominal Bore Schedule 40 weld Tee to ANSI B16.9