Steel Industry Glossary
- Bevel
- The end preparation machined on a butt weld fitting to ASME B16.25 so it matches the welding procedure.
- Branch Outlet
- A forged reinforced outlet — weldolet, sockolet, threadolet and similar — that replaces a pad-reinforced branch connection.
- Flange Facing
- The gasket seating surface of a flange — raised face, flat face or ring type joint — and the finish machined into it.
- Heat Number
- The melt identifier stamped on each item and carried on the certificate, linking the part to its chemistry and test results.
- Long Radius vs Short Radius
- Elbow centre-line radius: long radius is 1.5 times the nominal diameter, short radius is 1.0 — a pressure drop and space trade-off.
- PMI
- Positive material identification — an on-the-spot alloy verification by X-ray fluorescence or optical emission before despatch.
- Pressure Class
- The ASME B16.5 rating designation — Class 150 to Class 2500 — whose allowable pressure falls as temperature rises.
- Schedule
- The wall thickness designation of pipe and fittings — SCH 10 through SCH 160 and XXS — set against the nominal pipe size, not the outside diameter.
- Spiral Wound Gasket
- A gasket of alternating metal winding and soft filler, sized to the flange and rating per ASME B16.20.
- Stub End
- A short fitting with a lapped face, used with a loose backing flange so the flange can rotate for bolt alignment.