Forgings & flanges
Forged flanges to ASME B16.5 and B16.47 in corrosion resistant alloys
Weld neck, slip-on, blind, socket weld, threaded, lap joint and long weld neck flanges forged from nickel alloys, titanium, duplex and special stainless steel, Class 150 through Class 2500.
Dimensions and reference data
| Flange type | Typical size range | Where it is used | Notes |
|---|---|---|---|
| Weld neck (WN) | NPS ½ – 24 (B16.5) | High pressure, high temperature, cyclic duty | Butt welds to the pipe; best fatigue resistance |
| Long weld neck (LWN) | NPS ½ – 24 | Vessel nozzles, heater connections | Acts as an integral reinforcing nozzle |
| Slip-on (SO) | NPS ½ – 24 | Low pressure, low cost general service | Two fillet welds; lower fatigue life |
| Blind (BL) | NPS ½ – 24 | Line termination and future tie-ins | Must be rated for full pressure plus bolt load |
View all 7 rows
| Flange type | Typical size range | Where it is used | Notes |
|---|---|---|---|
| Socket weld (SW) | NPS ½ – 3 | Small bore instrument and sampling lines | ASME B16.11 dimensions for the socket |
| Threaded (TH) | NPS ½ – 4 | Non-critical utility lines | Thread to ASME B1.20.1 NPT |
| Lap joint (LJ) | NPS ½ – 24 | Systems requiring frequent dismantling | Used with a stub end to ASME B16.9 |
Bolting dimensions, hub dimensions and facing finish are taken from the current ASME B16.5 tables; a complete dimension sheet is issued with every order confirmation.
| Pressure class | Typical application | Facing options | Gasket type commonly used |
|---|---|---|---|
| 150 | Water, seawater, low pressure process lines | RF / FF | Spiral wound, soft cut gasket |
| 300 | General chemical and refinery process | RF / RTJ | Spiral wound with graphite filler |
| 600 | High pressure hydrocarbon and steam | RF / RTJ | Spiral wound or ring joint |
| 900 | High pressure gas and wellhead piping | RTJ | Octagonal or oval ring joint |
| 1500 | Wellhead, choke and kill manifolds | RTJ | BX or RX ring type joint |
| 2500 | Extreme pressure HPHT service | RTJ | BX ring type joint to API 6A |
Specifications and options
| Dimensional standard | ASME B16.5 for NPS ½ – 24; ASME B16.47 Series A (MSS SP-44) or Series B (API 605) for NPS 26 – 60; ASME B16.1 where applicable |
|---|---|
| Facing standard | ASME B16.5 raised face 1.6 mm or 6.4 mm; ring joint grooves to ASME B16.20 |
| Nickel alloy material | ASTM B564 / ASME SB-564 - N06625, N07718, N10276, N06022, N10675, N04400, N05500, N08825, N08810, N06600 |
| Titanium material | ASTM B381 / ASME SB-381 - Grade F2, F5, F7, F12 |
| Stainless / duplex material | ASTM A182 F304L, F316L, F321, F347, F44, F51 / F60, F53, F904L |
| Manufacturing route | Saw cut billet, inductively heated, closed die forged or ring rolled, solution annealed and quenched |
| Machining allowance | Hub, bore and facing fully machined; bolt holes drilled to ASME B16.5 tolerance |
| Testing | Tensile, hardness and impact on prolongation test coupons; 100 % ultrasonic testing available to ASTM A388 or customer specification |
| Marking | MSS SP-25 - manufacturer, size, class, material designation, heat number, facing type |
| Certification | EN 10204 3.1, plus SGS third party test report on request |
Typical applications
- Wellhead, Christmas tree, choke and kill manifold connections to API 6A
- Subsea manifolds, riser base connections and pipeline end terminations
- Chemical reactor nozzles, heat exchanger channels and column connections
- Flue gas desulphurisation absorber nozzles and slurry pump connections
- Desalination high pressure membrane housing and energy recovery connections
- Nuclear and conventional power station piping penetrations
- Marine piping systems carrying seawater, ballast and bilge water
How to order forged flanges
Send us the following and we will return a quotation within 24 hours: alloy grade or UNS number, dimensions including schedule or wall thickness, governing material and dimensional standards, quantity, required heat treatment, non-destructive testing scope, certificate type and any third party inspection requirement.
Forged Flanges frequently asked questions
Can you supply RTJ flanges with the correct groove hardness?
Yes. For ring type joint facings we control hardness below that of the mating ring so the softer, cheaper ring deforms rather than the groove. Typical limits are around 170 HB minimum up to a maximum agreed with the project.
What is the difference between ASME B16.47 Series A and Series B flanges?
Series A flanges are heavier and thicker with larger bolting derived from MSS SP-44; Series B flanges are lighter with more, smaller bolts derived from API 605. Series A has higher pressure capability and is preferred for critical, high moment loads.
Do you supply large diameter flanges above NPS 24?
Yes, up to NPS 60 to ASME B16.47. Very large flanges are normally produced by ring rolling and finished on a vertical boring mill to maintain grain flow and dimensional accuracy.
Can you provide a full material and bolting package?
We can ship flanges with matching gaskets to ASME B16.20 or B16.21 and stud bolts to ASTM A193 / A194 or ASTM A453 Grade 660 for high temperature work, consolidated on one certificate package.
Which nickel alloy flanges are most requested?
ASTM B564 Inconel 625 for seawater and sour service, Hastelloy C-276 for chemical duty, Incoloy 825 for acid lines and Inconel 718 where age hardened strength is required for API 6A hardware.
What is your minimum order quantity?
There is no minimum for standard sizes held in stock, and small prototype batches are accepted for special classes or unusual material combinations.