Weld Neck Flange Supplier Saudi Arabia — ASTM A105, A182 F11/F22, F304L/F316L

• Class 600, 900, 1500, 2500 pressure class
• Category M (toxic/flammable) service per B31.3
• Cyclic service with high thermal gradient
• Cryogenic service (LNG, low-temp CS)
• Sour service (NACE MR0175 — H₂S bearing)
• Radiographic examination required (100% RT)

Standard Bore (SB): Bore tapers to match pipe wall schedule — the bore diameter matches the pipe bore. Creates a smooth, step-free internal bore through the weld.

Full Bore (FB): Bore equals pipe ID with no reduction at any schedule. Required by SAES-L-108 for 6 NPS and larger on crude oil and gas service. Eliminates any internal step that would cause solids buildup or pressure drop.

• RF — Raised Face: Class 150–600 standard. Spiral wound gasket.
• RTJ — Ring Type Joint: Class 600–2500 on high-pressure gas, sour service, and Aramco high-pressure lines. Oval or octagonal ring.
• FF — Flat Face: Used with cast iron or non-metallic mating flanges. Not common on Aramco process piping.

A standard bore (SB) weld neck flange has an inside diameter that matches the pipe schedule — the bore tapers to the pipe wall thickness at the weld joint. A full bore (FB) weld neck flange has a bore equal to the pipe inside diameter at all schedules, eliminating the internal step. Saudi Aramco piping specifications (SAES-L-108) require full bore weld neck flanges on all piping 6 NPS and larger where flow restriction must be minimized — particularly crude oil, gas, and SAEP-347 Category M service lines. Gulf Union Ozone can supply both types; specify SB or FB in your RFQ.

For Class 900 weld neck flanges on Saudi Aramco projects, the standard facing is Raised Face (RF) with a spiral wound gasket for most process services. Ring Type Joint (RTJ) facing is required for sour service (NACE MR0175), high-pressure gas service above 100 bar, and wherever the piping class specifies RTJ. For Class 1500 and Class 2500, RTJ is the default on Aramco projects. Confirm with your Aramco piping class document — specify the piping class reference in your RFQ.

Yes. Gulf Union Ozone supplies weld neck flanges per ASME B16.47 Series A (MSS SP-44) and Series B (API 605) for large bore piping from NPS 26 to NPS 60. ASME B16.47 covers sizes that exceed the ASME B16.5 scope (up to NPS 24). Series A (MSS SP-44) is the standard for most Aramco large bore process piping; Series B (API 605) is used for pipeline applications. Large bore flanges are typically project-ordered with 4–8 week lead times — include your size, class, series, and material in the project inquiry.