Monel 400 Butt Weld Fittings | UNS N04400 SB-564

Monel 400 butt weld fittings (UNS N04400) forged to ASME SB-564 and dimensioned to ASME B16.9. This nickel-copper alloy is not a chromium alloy, so it resists reducing acids, caustic alkalis and chloride stress-corrosion cracking intrinsically, without relying on a passivation film.

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This page covers the alloy dimension. For the full range of butt weld fitting forms in any nickel alloy, see our nickel alloy butt weld fittings overview.

Specification

DesignationValue
UNS numberN04400
Material specificationASME SB-564 (Nickel Alloy Forgings)
Dimensional standardASME B16.9
Material classNickel-copper

Note on specifications: SB-564 is the correct ASME Section II specification for forged nickel alloy fittings. SA-182 covers low alloy and stainless steel only and does not include any nickel alloy grades.

Product Range

FittingTypes
Socket weld elbow45°, 90°, 180° / reducing
Socket weld teeEqual and reducing, straight and branch
Socket weld crossEqual and reducing
Socket weld reducerConcentric and eccentric
Socket weld couplingStandard
Socket weld capStandard and heavy
PlugSquare head and hex head

Chemical Composition (ASME SB-564)

ElementComposition, %ElementComposition, %
Nickel (by difference)63.0 minCarbon0.3 max
Copper28.0 min – 34.0 maxManganese2.0 max
Iron2.5 maxSilicon0.5 max
Sulfur0.024 max

Limits from ASME SB-165 Table 2. Nickel is determined arithmetically by difference.

Dimensional Range

Condition and sizeTensile, min psi (MPa)Yield (0.2%), min psi (MPa)Elongation, min %
Annealed, 5 in. (127 mm) OD and under70 000 (480)28 000 (195)35
Annealed, over 5 in. (127 mm) OD70 000 (480)25 000 (170)35

Quality Control

  • EN 10204 3.1 mill test certificate on every fitting
  • Full chemical analysis by XRF or OES, actual heat values on the certificate
  • Dye penetrant inspection on every fitting; ultrasonic testing on heavy wall and forgings
  • Dimensional inspection against the governing dimensional standard
  • Intergranular corrosion testing to ASTM G28 available on request
  • Third-party inspection by Lloyd’s, BV, DNV, SGS or TUV on request

Surface, Marking and Packing

Fittings are supplied solution annealed and pickled, with a bright annealed or pickled surface as required. Each fitting carries heat number, grade, standard, size, heat treatment condition and our works mark. Export packing in wooden cases or steel pallets with plastic end caps.

Technical Enquiries

Send the grade, fitting type, nominal size, schedule, quantity and any third-party inspection requirement to our technical sales desk. We will confirm dimensional tolerance, delivery condition and the applicable ASME line item, and quote FOB Shanghai or Ningbo.

Applications

  • Hydrofluoric acid and alkylation plant piping
  • Caustic and alkalis handling
  • Sour gas and H2S service where chloride SCC is a risk
  • Seawater instrumentation and control lines
  • Oil and gas refining and sour water handling

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Frequently Asked Questions

Why Monel 400 rather than a stainless steel?

Monel 400 is essentially immune to chloride stress-corrosion cracking and handles reducing acids such as hydrochloric and sulphuric acid, which stainless steels do not. It is poor in oxidising media such as aerated nitric acid or wet chlorine, so it complements rather than replaces the stainless grades.

What condition should I specify?

Annealed, if the fittings will be cut, bevelled or otherwise worked on. Stress relieved material has much higher strength but far lower elongation, so it suits rigid pre-stressed installations only.

Can Monel 400 be welded?

Yes, and it welds readily. Use a matching or ENiCuMonel filler, control interpass temperature to about 150°C, and avoid annealing after cold forming, which can embrittle the material.

Do you supply EN 10204 3.1 certificates?

Yes, as standard, with third-party inspection available on request.

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