Monel 400 Tube Fittings are made to Alloy 400, UNS N04400 for seawater and HF acid service. Double and single ferrule compression fittings connect Monel 400 instrument and control tubing.
Raaj Fittings machines Monel 400 tube fittings in-house at our two plants in India, in metric and imperial tube sizes, and exports them to EPC contractors, fabricators and stockists across the Middle East, Europe and the Americas, with full traceability and EN 10204 certificates.
| Material specification | Alloy 400, UNS N04400 |
|---|---|
| Tube OD | Metric 3 to 25 mm; imperial ⅛" to 1" |
| Fitting types | Double ferrule and single ferrule compression fittings; unions, connectors, elbows, tees, bulkheads and adapters |
| End connections | Compression tube ends; NPT (ASME B1.20.1), BSPT and BSPP (BS 21 / ISO 7-1) threads |
| Certification | EN 10204 3.1 mill test certificate as standard; EN 10204 3.2 on request |
Alloy 400 (UNS N04400) is a nickel-copper alloy with about 65% nickel and 30% copper. It is renowned for resisting fast-flowing seawater, hydrofluoric acid and alkalis, and it keeps good toughness from cryogenic temperatures to about 480 °C.
| Element, % | N04400 |
|---|---|
| Nickel (Ni, incl. Co) | 63.0 min |
| Copper (Cu) | 28.0 – 34.0 |
| Iron (Fe) | 2.5 max |
| Manganese (Mn) | 2.0 max |
| Carbon (C) | 0.3 max |
| Silicon (Si) | 0.5 max |
| Sulphur (S) | 0.024 max |
Mechanical properties are as required by the ordered ASTM specification and are reported on the mill test certificate.
| UNS | Werkstoff Nr. | EN / DIN | Other |
|---|---|---|---|
| N04400 | 2.4360 | NiCu30Fe | Monel® 400 |
Monel 400 tube fittings are machined from certified bar and used with Monel 400 tubing in instrument, sampling and injection lines carrying aggressive media. Fittings and tubing must be the same alloy so the ferrules grip correctly.
Bar stock is PMI-verified and traceable by heat number; bodies, nuts and ferrules are dimensionally inspected and threads gauge-checked. Every order is supplied with EN 10204 3.1 certificates, with EN 10204 3.2 certification and third-party inspection by the buyer's nominated agency on request.
Alloy 400 is one of the few materials with good resistance to hydrofluoric acid, so it is the standard choice for piping and fittings in refinery HF alkylation units.
Yes, especially flowing seawater. In stagnant seawater, crevices and deposits can cause pitting, so design and maintenance should avoid stagnant conditions.
They should be used with Monel 400 tubing. Matching the materials ensures the ferrules grip correctly and that no part of the joint becomes the weak point for corrosion.
Every order is supplied with EN 10204 3.1 mill test certificates showing heat chemistry and mechanical properties to Alloy 400, UNS N04400. EN 10204 3.2 certification and inspection by your nominated third-party agency are available on request.