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 Pipe — UNS N04400 Seamless & Welded per ASTM B165, B725, B775
Monel 400 pipe (UNS N04400, also known as Alloy 400, Nickel 400) is the standard nickel-copper pipe for hydrofluoric acid service, hot seawater piping, brine handling, and reducing chemical lines where 316L stainless cannot survive. TorqBolt supplies Monel 400 pipe in seamless (ASTM B165), welded (ASTM B725), and welded-with-NDE (ASTM B775) per customer's spec, sizes 1/8″ NPS through 24″ NPS, schedules 5 through XXS, in lengths to 6 m. EN 10204 3.1 or 3.2 certification supplied.
Size Range & Schedules
| NPS | OD (mm) | Sch 10 wall | Sch 40 wall | Sch 80 wall |
|---|---|---|---|---|
| 1/2″ | 21.3 | 2.11 | 2.77 | 3.73 |
| 3/4″ | 26.7 | 2.11 | 2.87 | 3.91 |
| 1″ | 33.4 | 2.77 | 3.38 | 4.55 |
| 2″ | 60.3 | 2.77 | 3.91 | 5.54 |
| 3″ | 88.9 | 3.05 | 5.49 | 7.62 |
| 4″ | 114.3 | 3.05 | 6.02 | 8.56 |
| 6″ | 168.3 | 3.40 | 7.11 | 10.97 |
| 8″ | 219.1 | 3.76 | 8.18 | 12.70 |
| 12″ | 323.9 | 4.57 | 10.31 | 17.48 |
Chemistry — UNS N04400
Cr 0 / Mo 0 / Ni 63 min / Cu 28-34 / Fe 2.5 max / Mn 2.0 max / S 0.024 max / Si 0.50 max / C 0.30 max. See full element ranges.
Mechanical Properties (Annealed)
Tensile 70 ksi (485 MPa) min. Yield 28 ksi (195 MPa) min. Elongation 35% min. Hardness HRB 60-80 typical. See full mechanical specification.
Manufacturing Routes
- Seamless (ASTM B165): hot-extruded then cold-pilgered or cold-drawn. Highest pressure integrity, preferred for HF and critical service.
- Welded ERW (ASTM B725): longitudinal seam, autogenous TIG or GTAW. Cost-effective for low-pressure lines.
- Welded with NDE (ASTM B775): ultrasonic + eddy-current tested. Required by some piping codes.
Common Pipe Applications
- Hydrofluoric acid alkylation lines (HF refinery)
- Hot seawater intake / brine piping
- Sulfuric acid handling < 80% concentration
- Caustic soda evaporator lines
- Marine heat-exchanger tubing risers
- Naval shaft seal piping
Applicable Standards
- ASTM B165 - seamless pipe and tube
- ASTM B725 - welded pipe
- ASTM B775 - welded with NDE
- ASME SB-165 / SB-725 (boiler code)
- ASME B36.19 (stainless steel pipe dimensions reference)
- NACE MR0103 (where sour service overlap)
Testing & Certification
Standard tests on every heat: tensile (yield/UTS/elongation), hardness, hydrostatic pressure (where applicable), eddy current or ultrasonic per ASTM B775. Certification supplied to EN 10204 3.1 or 3.2 on request. PMI (positive material identification) marking on every length.
FAQs
What is the maximum pressure rating for Monel 400 pipe?
Pressure rating depends on schedule and temperature. Sch 80 NPS 2″ rated approximately 2300 psi at 100 °F per ASME B31.3. Above 480 °C, derating applies. Request our pressure-temperature chart for the size you need.
Is welded or seamless Monel 400 pipe preferred for HF service?
Seamless (ASTM B165). HF service is unforgiving on weld microsegregation. Most refinery HF specs explicitly require seamless construction.
What is the lead time for Monel 400 pipe?
Stock sizes (NPS 1/2 to 4 in Sch 10/40/80) ship in 1-2 weeks. Sizes above 6″ or special schedules typically 8-12 weeks mill-direct. Request a quote for your size and quantity.
Can Monel 400 pipe be coupled to stainless or carbon steel?
Yes, but a transition joint or flange must be designed for galvanic compatibility. Direct welded transitions between Monel 400 and SS 316/304 can cause galvanic corrosion at the interface in wet service. Use isolation flanges or Monel 400 transition spools.
Related Forms & Standards
- Monel 400 tubing — smaller-diameter alternative
- Monel 400 plate
- Monel 400 sheet
- Monel 400 round bar
- ASTM B165 specification
- Monel 400 fittings (compatibility)
- Monel 400 flanges
Satisfaction Survey
