Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Monel 400 Seamless Pipe - UNS N04400 ASTM B165, NPS 1/4 to 8, Sch 10 to 80
A Monel 400 seamless pipe (also Monel 400 pipe, Monel 400 pipes, UNS N04400 pipe, Alloy 400 seamless pipe) is the line-pipe form of the 67Ni-30Cu nickel-copper alloy, supplied to ASTM B165 with chemistry cross-referenced to ASTM B164 rod. Buttweld fittings ship in matching N04400 per ASTM B366 and forged flanges per ASTM B564. The pipe is specified where the process fluid is hydrofluoric acid, seawater, sour gas at NACE MR0175 limits, sodium hydroxide caustic or brackish heat-exchanger feed. Stock runs NPS 1/4 through NPS 8 in Schedule 10, 40 and 80; NPS 10 and 12 on indent. Monel® is a trademark of Special Metals Corporation.
ASTM B165 Scope - Seamless Pipe and Tube for UNS N04400
ASTM B165 / B165M covers seamless pipe and seamless tube of nickel-copper alloy UNS N04400 in the annealed and stress-relieved conditions, carrying dimensions, chemistry, mechanical minima, hydro test, NDE and certification rules. Welded pipe is outside B165 scope; welded N04400 pipe falls under ASTM B725 and welded tube under ASTM B775. B165 governs the pipe; ASME B36.10 governs the dimensional schedule.
Monel 400 Seamless Pipe Size Range (NPS 1/4 to NPS 8, Sch 10 / 40 / 80)
Outside diameter, wall thickness and weight follow ASME B36.10M. Sizing tolerance is per ASTM B165 paragraph 9: OD plus or minus 0.5 percent, wall thickness minus 12.5 percent of nominal, length plus 10 mm minus 0 on cut pieces, 6 m random on mill lengths. Schedule 10, Schedule 40 (standard wall) and Schedule 80 (extra strong) are the stock schedules; 5S and 5 are mill-to-order.
| NPS | OD (mm) | Sch 10 wall (mm) | Sch 40 wall (mm) | Sch 80 wall (mm) | Stock status |
|---|---|---|---|---|---|
| 1/4 | 13.7 | 1.65 | 2.24 | 3.02 | Mumbai stock |
| 3/8 | 17.1 | 1.65 | 2.31 | 3.20 | Mumbai stock |
| 1/2 | 21.3 | 2.11 | 2.77 | 3.73 | Mumbai stock |
| 3/4 | 26.7 | 2.11 | 2.87 | 3.91 | Mumbai stock |
| 1 | 33.4 | 2.77 | 3.38 | 4.55 | Mumbai stock |
| 1-1/4 | 42.2 | 2.77 | 3.56 | 4.85 | Mumbai stock |
| 1-1/2 | 48.3 | 2.77 | 3.68 | 5.08 | Mumbai stock |
| 2 | 60.3 | 2.77 | 3.91 | 5.54 | Mumbai stock |
| 2-1/2 | 73.0 | 3.05 | 5.16 | 7.01 | Mumbai stock |
| 3 | 88.9 | 3.05 | 5.49 | 7.62 | Mumbai stock |
| 4 | 114.3 | 3.05 | 6.02 | 8.56 | Mumbai stock |
| 6 | 168.3 | 3.40 | 7.11 | 10.97 | Mumbai stock |
| 8 | 219.1 | 3.76 | 8.18 | 12.70 | Mumbai stock |
| 10 | 273.0 | 4.19 | 9.27 | 15.09 | Indent, 10 to 12 weeks |
| 12 | 323.8 | 4.57 | 10.31 | 17.45 | Indent, 10 to 12 weeks |
Chemistry per ASTM B165 / B164 for UNS N04400
B165 references the B164 chemistry envelope: nickel plus cobalt at 63 percent minimum, copper at 28 to 34 percent; iron, manganese, carbon, silicon and sulfur capped. Reference chemical composition and UNS N04400.
| Element | Min (%) | Max (%) | Role |
|---|---|---|---|
| Nickel + Cobalt | 63.0 | - | Matrix; HF and seawater resistance |
| Copper | 28.0 | 34.0 | Solid-solution strengthener; HF resistance |
| Iron | - | 2.5 | Residual; controls magnetic permeability |
| Manganese | - | 2.0 | Deoxidiser; sulfur fixer |
| Carbon | - | 0.30 | Strength; capped for weldability |
| Silicon | - | 0.50 | Deoxidiser residual |
| Sulfur | - | 0.024 | Capped for hot workability and weldability |
Mechanical Properties of Annealed Monel 400 Pipe
ASTM B165 sets the annealed mechanical floor for N04400 pipe at 70 ksi (483 MPa) tensile min, 25 ksi (172 MPa) yield 0.2 percent offset min, 35 percent elongation min in 2 in. Hardness on the as-delivered pipe sits at HRB 60 to HRB 80, inside the NACE MR0175 ceiling. Stress-relieved pipe is offered for tighter yield bands at 540 to 590 degrees Celsius, 1 hour per inch of wall, air cool. Full reference on the mechanical properties page.
| Property | Annealed minimum (B165) | Typical mill value |
|---|---|---|
| Tensile strength | 70 ksi (483 MPa) | 75 to 85 ksi |
| Yield strength, 0.2% offset | 25 ksi (172 MPa) | 32 to 45 ksi |
| Elongation in 2 in. | 35% | 40 to 45% |
| Hardness, typical | - | HRB 60 to HRB 80 |
| NACE MR0175 hardness ceiling | 35 HRC | Cleared by design |
Hydrostatic Testing and Non-Destructive Examination
ASTM B165 paragraph 16 sets the hydrostatic test pressure from P = 2 S t / D, with S at 50 percent of the specified yield, t the specified wall and D the specified OD. Hold is 5 seconds minimum, mill-witnessed. The buyer may elect eddy-current testing per B165 paragraph 17.1 in place of hydro, or ultrasonic testing per paragraph 17.2 for wall above 0.150 in. nominal (ASTM E309 / E213 acceptance). Each length carries heat number, schedule, NPS, B165 mark and test result on the MTC.
Common Applications for Monel 400 Seamless Pipe
The N04400 seamless pipe runs in five repeat service positions across refining, offshore, chemical and power.
- HF alkylation acid lines at 70 to 95 percent HF in refinery alkylation per API RP 751. See HF alkylation, HF acid resistance.
- Seawater piping on offshore platforms, FPSO topsides, desalination feed and ballast water. See seawater corrosion, marine applications.
- Sour gas service at NACE MR0175 / ISO 15156-3 limits in gas gathering, sour gas separation and amine sweetening loops. See sour service, NACE MR0175.
- NaOH caustic loops in chlor-alkali, kraft recovery and refinery caustic regeneration up to 80 percent NaOH at 130 degrees Celsius.
- Brackish heat-exchanger feed lines on once-through and closed-loop cooling where the make-up water is chloride-rich.
Certification and Traceability (EN 10204 Type 3.1 / 3.2)
Standard supply ships with EN 10204 type 3.1 MTC: heat number, melt composition, mechanical results, hydrostatic record, NDE record and B165 marking, signed by mill QA. EN 10204 type 3.2 adds a third-party witness signature (Lloyd's Register, BV, DNV, TUV or buyer inspector) and is mandated for sour service, category III pressure equipment under PED 2014/68/EU and offshore client specs (NORSOK, Aramco SAES, ADNOC ESP). PMI by handheld XRF is recommended at every joint; the alloy registers Ni 63 to 70 percent and Cu 28 to 34 percent on the analyser. Heat-number traceability is preserved from mill ingot through pipe to flange to fitting per ASTM A484 Appendix A1.
Connection Options and Fittings Compatibility
The N04400 piping system is built end-to-end in matching nickel-copper. Buttweld fittings to ASME B16.9 (long-radius elbow, tee, concentric and eccentric reducer, cap, lap-joint stub end) ship as N04400 per ASTM B366. Socket-weld and threaded fittings to ASME B16.11 ship as N04400 forged stock per ASTM B564. Forged flanges to ASME B16.5 in WN, SO, SW, BL, LJ, RTJ and Threaded face configurations ship to ASTM B564. Bolting is ASTM F468 Class A Monel 400 bolts with matched ASTM F467 nuts and Monel 400 washers. Reference the fittings and flanges pages for the matched-chemistry envelope.
Frequently Asked Questions
What is Monel 400 seamless pipe used for? The pipe carries hydrofluoric acid in HF alkylation units, seawater on offshore platforms, sour gas at NACE MR0175 limits, sodium hydroxide in caustic loops and brackish water in heat-exchanger feed lines. The 67Ni-30Cu composition holds against HF from 70 to 95 percent and chloride-bearing seawater.
What schedules and sizes are available in Monel 400 pipe? Stock is NPS 1/4 through NPS 8 in Schedule 10, Schedule 40 and Schedule 80 per ASME B36.10. NPS 10 and NPS 12 ship on indent with 10 to 12 week lead time. Mill lengths 6 m random; cut lengths to 0.1 m tolerance.
Is Monel 400 pipe NACE MR0175 qualified for sour service? Yes. ASTM B165 annealed Monel 400 meets NACE MR0175 / ISO 15156-3 for the nickel-copper alloy group at a 35 HRC ceiling. EN 10204 type 3.2 certification with NACE statement ships on every sour shipment.
What is the difference between seamless and welded Monel 400 pipe? ASTM B165 covers seamless pipe and tube only, made by extrusion or pierce-and-pilger, free of a weld seam. Welded N04400 pipe is covered by ASTM B725 and welded tube by ASTM B775. Seamless is preferred for HF alkylation, sour service and high-cycle fatigue duty.
Related Pages
Specifications: ASTM B165, B164, B127, B163, B564, F468, F467, UNS N04400, DIN 17743, NACE MR0175. Companion forms: tubing, fittings, flanges, forgings, round bar, plate, sheet. Properties: chemical composition, mechanical properties, corrosion resistance, welding, seawater corrosion, HF acid resistance, sour service, Monel 400 reference, pricing.
Request a Quote. For Monel 400 seamless pipe and pipes to ASTM B165, send NPS, schedule, length, quantity, end finish (plain, bevelled, threaded) and certification class (EN 10204 type 3.1 or 3.2) to info@torqbolt.com or WhatsApp +91-22-66157017. Heat-numbered MTC plus Mumbai ex-stock price inside one working day; export through JNPT.
References. ASTM B165 / B165M (Seamless Pipe and Tube, Nickel-Copper Alloy). ASTM B164 (Rod, Bar, Wire). ASTM B366 (Buttweld fittings). ASTM B564 (Forgings). ASME B36.10M (dimensional schedule). ASME B16.9 (Buttweld fittings). ASME B16.11 (Forged socket-weld and threaded fittings). ASME B16.5 (Pipe flanges). NACE MR0175 / ISO 15156-3 (H2S sour service). EN 10204 (Inspection certificates). API RP 751 (HF alkylation unit safety).
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