Monel Pipe Fittings
Giriraj Impex is a manufacturer, stockist, supplier and exporter of Monel pipe fittings in Monel 400 (UNS N04400). We manufacture Monel butt-weld fittings to ASTM B366 / ASME SB366 grade WPNC and ASME B16.9 and MSS SP-43, and forged socket weld and threaded fittings from ASTM B564 forgings to ASME B16.11, with mill test certificates.
Monel pipe fittings carry the corrosion resistance of Monel piping through bends, branches and size changes in seawater, HF alkylation, caustic soda, brine and chemical service, where a fitting in a lesser material would become the weak point of the line.
Specifications
| Item | Details |
|---|---|
| Butt-weld fittings | ASTM B366 / ASME SB366 – WPNC (Monel 400); seamless (S) or welded (W) |
| Forged fittings | From ASTM B564 / ASME SB564 forgings – Monel 400 |
| Dimensions | ASME B16.9, MSS SP-43 (butt weld); ASME B16.11, MSS SP-97 (forged) |
| Sizes | Butt weld ½" to 24" NB; forged ¼" to 4" NB |
| Wall / class | Sch 5S, 10S, 40S, 80S and to match pipe; forged Class 2000, 3000, 6000, 9000 |
| Types | 45°, 90° and 180° elbows, equal and reducing tees, concentric and eccentric reducers, caps, stub ends, crosses; socket weld and threaded elbows, tees, couplings, unions, plugs, bushings; olets |
| Condition | Annealed |
| Documents | Mill test certificate (MTC); third-party inspection on request |
Chemical composition and mechanical properties
| Alloy | Ni | Cu | Fe | Mn | C | Si | S | Al | Ti |
|---|---|---|---|---|---|---|---|---|---|
| 400 (N04400) | 63.0 min | 28.0–34.0 | 2.5 | 2.0 | 0.3 | 0.5 | 0.024 | – | – |
| K-500 (N05500) | 63.0 min | 27.0–33.0 | 2.0 | 1.5 | 0.25 | 0.5 | 0.01 | 2.30–3.15 | 0.35–0.85 |
Nickel includes cobalt. Limits as given in ASTM B127, B164 and B165 (alloy 400) and B865 (alloy K-500).
| Product | Tensile strength, MPa (ksi) | Yield strength 0.2%, MPa (ksi) | Elongation, % |
|---|---|---|---|
| Plate and sheet – ASTM B127 | 483 (70) | 193 (28) | 35 |
| Seamless pipe and tube – ASTM B165 | 483 (70) | 193 (28) | 35 |
| Rod and bar – ASTM B164 | 483 (70) | 172 (25) | 35 |
| Forgings – ASTM B564 | 483 (70) | 172 (25) | 35 |
Annealed condition. Hot-rolled, cold-worked and stress-relieved conditions have higher strength, with size limits as given in each standard.
ASTM B366 requires fittings to meet the properties of the pipe, plate or forging they are made from. Background on the alloy is on the Monel page.
Butt-weld and forged Monel fittings
Butt-weld fittings are welded to the pipe with a full-penetration weld and are used for most process lines from ½" upward. They give a smooth bore with no crevices, which matters in corrosive service where crevices can concentrate chlorides or acid. Forged socket weld and threaded fittings are used for small-bore lines, instrument connections, vents and drains. Socket weld joints leave a small gap at the root, so in severe crevice-corrosion service, butt-weld fittings may be preferred even in small sizes. Stub ends are used with loose lap joint flanges to reduce the amount of Monel needed at flanged joints.
How we manufacture Monel fittings
Seamless butt-weld fittings are formed from Monel 400 pipe, and welded fittings from B127 plate welded with nickel-copper filler and radiographed as ASTM B366 requires. Elbows are formed by mandrel bending, tees by hydraulic bulging or extrusion, and reducers by pressing. Fittings are annealed after forming, then descaled, machined to bevel ends and inspected to ASME B16.9. Forged fittings are machined from B564 forgings to ASME B16.11. Each fitting is marked with WPNC or the alloy designation, size, schedule or class and heat number.
Service considerations
Fittings experience higher flow velocities and turbulence than straight pipe, especially at elbows and tees. Monel 400 tolerates flowing seawater well, which suits it to fittings in pump discharge and cooling-water lines. In HF alkylation units, Monel fittings are used where acid and hydrocarbon mixtures change direction or concentration, and where carbon steel would suffer accelerated attack. For HF service, the fitting and weld should be specified with the hardness and stress-relief requirements of the licensor or the project specification.
Welding
Monel fittings are welded to Monel pipe with ERNiCu-7 filler by TIG, with argon backing for the root, on joints cleaned of oil, paint and marking materials. Joints between Monel and carbon steel or stainless steel use nickel-based filler metals selected for the combination. No post-weld heat treatment is normally needed for corrosion resistance.
Ordering Monel pipe fittings
Please give the fitting type, size, wall schedule or class, seamless or welded construction, end connection, quantity and any additional testing or inspection. Fittings are packed in wooden boxes with bevel protection and are traceable to their mill test certificates.
Applications and related products
Monel pipe fittings are used in seawater cooling, ballast and firewater systems, HF alkylation units, caustic soda and brine plants, crude oil overhead systems and chemical processing. Matching products include Monel pipes and tubes, Monel flanges, Monel sheets and plates, Monel round bars and Monel fasteners. Fittings in other materials are on the pipe fittings page.
Frequently Asked Questions
WPNC is the ASTM B366 grade designation for butt-weld fittings in Monel 400 (UNS N04400).
ASTM B366 covers the material of Monel butt-weld fittings, and ASME B16.9 and MSS SP-43 cover their dimensions.
Yes. Socket weld and threaded Monel fittings are made from ASTM B564 forgings to ASME B16.11 in Class 2000 to 9000.
ERNiCu-7 nickel-copper filler metal is used to weld Monel fittings to Monel pipe.
Yes. Monel 400 fittings are widely used in HF alkylation units because of the alloy's resistance to hydrofluoric acid.
Butt-weld fittings from ½" to 24" NB and forged fittings from ¼" to 4" NB.
Request a Quote for Monel Pipe Fittings
Tell us the product, grade, size, standard, quantity and delivery location, and our sales team will reply with a quotation.
Monel® is a trademark of Special Metals Corporation.