Tesco Steel & Engineering manufactures ASTM B564 Monel 400 flanges — nickel-copper alloy flanges in grade Monel 400 (UNS N04400), ~63% nickel and ~30% copper. Monel 400 delivers outstanding resistance to seawater, hydrofluoric (HF) acid, brine, alkalis and reducing acids, with strong resistance to chloride stress-corrosion cracking — the standard alloy for marine, offshore, refinery HF-alkylation and chemical-process piping. Available in weld neck, slip-on, blind, socket-weld, threaded, lap-joint and plate types to ASME B16.5 / B16.47. Class 150 to 2500, NPS 1/2″ to 24″, PN6 to PN400. ISO 9001:2015 certified. Made in India.
Monel 400 (ASTM B564 / UNS N04400) Flanges
Monel 400 Weld Neck & Blind Flanges
Tesco Steel & Engineering manufactures Monel 400 flanges per ASTM B564 and ASME B16.5, in all flange types from weld neck to blind, Class 150 to 2500 — supplied with EN 10204 3.1 / 3.2 certification, PMI and third-party inspection on request. Explore the wider Monel flange range, UNS N04400 Monel flanges, Monel K500 (B564) flanges, and the flange dimension charts.
| ASTM B564 Monel 400 flanges are available in the following specifications: | |
|---|---|
| Material Grade | Monel 400 / UNS N04400 / ASTM B564 / DIN 2.4360 / NiCu30Fe |
| Alloy Type | Nickel-copper (~63% Ni, ~30% Cu) — solid-solution, non-age-hardenable |
| Size | 1/2″ NB to 24″ NB (DN 15 to DN 600); larger to ASME B16.47 |
| Class / Rating | 150#, 300#, 600#, 900#, 1500#, 2500# · 3000#, 6000#, 9000# (socket-weld / threaded) |
| Pressure Ratings | PN 6 – PN 400 (PN6, 10, 16, 25, 40, 64, 100, 160, 250, 320, 400) |
| Schedule / Wall Thickness | STD, XS, XXS, SCH 10, 20, 40, 80, 160 |
| Standards | ASTM B564 (forgings), ASME B16.5, ASME B16.47 (Series A & B), MSS SP-44, DIN EN 1092-1 |
| Flange Types | Weld Neck (WNRF), Slip-On (SORF), Blind, Socket Weld (SWRF), Lap Joint, Threaded / Screwed, Plate, Long Weld Neck, Orifice |
| Flange Faces | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), Tongue & Groove (T&G) |
| Weld Filler | ERNiCu-7 (AWS A5.14) / ENiCu-7 (AWS A5.11) |
| Testing | PMI, hydrostatic, UT, MT/PT, hardness per spec; EN 10204 3.1 / 3.2 |
Monel 400 is a nickel-rich nickel-copper alloy. Its high nickel content gives resistance to reducing acids and hydrofluoric acid, while the copper content provides excellent resistance to flowing seawater and brine. It is not hardenable by heat treatment; strength is increased only by cold working.
| Element | Monel 400 (UNS N04400) |
|---|---|
| Nickel (Ni) | 63.0% min |
| Copper (Cu) | 28.0 – 34.0% |
| Iron (Fe) | 2.50% max |
| Manganese (Mn) | 2.00% max |
| Carbon (C) | 0.30% max |
| Silicon (Si) | 0.50% max |
| Sulphur (S) | 0.024% max |
| Mechanical Property (annealed, ASTM B564) | Value |
|---|---|
| Tensile Strength (min) | 480 MPa (70 ksi) |
| Yield Strength 0.2% (min) | 195 MPa (28 ksi) |
| Elongation (min) | 35% |
| Hardness (typical) | 110–150 HB |
| Density | 8.80 g/cm³ |
| Melting Range | 1300–1350 °C |
| Max Service Temp | ~480–540 °C (environment-dependent); suitable to cryogenic |
| Standard | Monel 400 Designation |
|---|---|
| UNS (USA) | N04400 |
| ASTM (forgings / flanges) | B564 (also B127 plate, B164 bar) |
| EN / DIN (Europe) | 2.4360 / NiCu30Fe |
| Werkstoff | 2.4360 |
| BS (UK) | 3076 NA13 |
| ISO | NW4400 |
| Common trade name | Monel 400 |
Monel 400 Weld Neck (WNRF)
Monel 400 Slip-On (SORF)
Monel 400 Blind (BFF)
| Flange Type | Description & Monel-400-Specific Use |
|---|---|
| Weld Neck (WNRF) | Tapered hub butt-welded to pipe for high-integrity seawater, HF-acid and brine lines; weld with ERNiCu-7 filler, no PWHT. |
| Slip-On (SORF) | Fillet-welded over the pipe; common in marine and chemical secondary piping where alignment ease is wanted. |
| Blind (BFF) | Seals pipe ends and vessel nozzles in corrosive marine/acid service; the default for capped seawater and HF nozzles. |
| Socket Weld (SWRF) | Small-bore (1/2″–2″) instrument and chemical-injection connections in aggressive media. |
| Lap Joint (LJRF) | Used with a Monel stub end where frequent dismantling is needed; minimises costly alloy in the rotating ring. |
| Threaded (TRFF) | Internal NPT/BSP threads for low-pressure, non-welded connections in corrosive utility service. |
| Long Weld Neck / Orifice / Plate | Nozzle, flow-metering and plate flanges in Monel 400 for marine and chemical-process duty. |
| Property | Monel 400 (N04400) | Monel K500 (N05500) | Inconel 625 (N06625) | Cu-Ni 70/30 (C71500) |
|---|---|---|---|---|
| Type | Ni-Cu solid solution | Ni-Cu age-hardenable | Ni-Cr-Mo | Copper-nickel |
| Hardenable | No (cold work only) | Yes (Al+Ti, aged) | No | No |
| Seawater / brine | Excellent | Excellent | Excellent | Excellent |
| Hydrofluoric (HF) acid | Excellent | Excellent | Good | Limited |
| Oxidising acids (HNO₃) | Poor | Poor | Good | Poor |
| Strength | Moderate | High (aged) | High | Lower |
| Flange spec | ASTM B564 | ASTM B564 | ASTM B564 | ASTM B151/B564 |
| Best For | Seawater, HF alkylation, brine, alkalis | High-strength shafts, fasteners in seawater | Oxidising + reducing, high temp | Marine condenser/seawater piping |
Excellent resistance to flowing seawater, brackish water and brine with low chloride-SCC susceptibility — ideal for marine and desalination.
One of the few alloys that resists HF acid across wide concentrations — the standard for refinery HF alkylation units.
Retains strength and toughness from cryogenic temperatures up to ~480–540 °C without embrittlement.
Strong in sulphuric and hydrochloric acids (reducing conditions) and in caustic/alkaline media.
| Industry | Typical Application |
|---|---|
| Marine & Offshore | Seawater cooling, ballast, firewater and deck piping; pump & valve flanges |
| Oil & Gas Refining | HF alkylation units, crude distillation overheads, sour-service connections |
| Chemical Processing | Sulphuric / hydrochloric / hydrofluoric acid, alkali and chlorinated-solvent piping |
| Desalination | Seawater feed and brine piping, evaporator and heat-exchanger nozzles |
| Power Generation | Feedwater heaters and condenser connections in seawater-cooled plants |
| Pumps & Valves | Corrosion-resistant flanged connections for valves, pumps and instruments |
Forged from certified nickel-copper alloy with PMI verification — full chemistry and Ni/Cu confirmation on the MTC.
WNRF, SORF, blind, socket-weld, threaded, lap-joint, LWN, orifice and plate — in RF, FF, RTJ and T&G faces.
EN 10204 3.1 / 3.2 MTC, heat/lot traceability, hydrostatic and third-party inspection on request.
Supplied to marine, refinery and chemical projects across 90+ countries with full documentation.
Monel 400 flange prices track the high nickel and copper content, plus size, pressure class, flange type and quantity — so they carry a premium over stainless grades. Tesco Steel & Engineering offers competitive ex-works pricing from Mumbai with full export documentation and material traceability. Click Ask for Quote or message us on WhatsApp at +91 92233 66922 with flange type, size (NB), pressure class, quantity and documentation requirements.
Q1. What is an ASTM B564 Monel 400 flange?
An ASTM B564 Monel 400 flange is a pipe flange forged from Monel 400 (UNS N04400), a nickel-copper alloy containing about 63% nickel and 30% copper. ASTM B564 is the specification for nickel-alloy forgings. Monel 400 offers outstanding resistance to seawater, hydrofluoric acid, brine, sulphuric and hydrochloric acids and alkalis, and is widely used in marine, refinery (HF alkylation) and chemical service. Flanges are machined to ASME B16.5 / B16.47 dimensions.
Q2. What is the chemical composition of Monel 400?
Monel 400 (UNS N04400) contains nickel 63% minimum, copper 28–34%, iron 2.5% max, manganese 2.0% max, carbon 0.3% max, silicon 0.5% max and sulphur 0.024% max. It is a single-phase solid-solution nickel-copper alloy that is not hardenable by heat treatment — only by cold working.
Q3. Why is Monel 400 used for hydrofluoric (HF) acid and seawater service?
Monel 400's high nickel content makes it one of the few alloys that resists hydrofluoric acid across a wide range of concentrations and temperatures, so it is the standard material for HF alkylation units in refineries. Its copper content gives excellent resistance to flowing seawater and brine with low susceptibility to chloride stress-corrosion cracking, making it a leading choice for marine, offshore and desalination piping.
Q4. What is the difference between Monel 400 and Monel K500 flanges?
Monel 400 (UNS N04400) is a solid-solution nickel-copper alloy that is not age-hardenable; it is used where corrosion resistance and moderate strength are required. Monel K500 (UNS N05500) adds aluminium and titanium so it can be precipitation (age) hardened to roughly three times the yield strength of 400, for pump shafts, fasteners and high-strength components. Both share the same excellent corrosion resistance; K500 is chosen when higher strength and hardness are also needed.
Q5. What standards and equivalents apply to Monel 400 flanges?
Monel 400 flanges are made to ASTM B564 (forgings, UNS N04400) and dimensioned to ASME B16.5 / B16.47. Equivalents include DIN 2.4360 / NiCu30Fe (Werkstoff 2.4360), BS 3076 NA13 and ISO NW4400. Related product specs are ASTM B127 (plate/sheet) and B164 (rod/bar).
Q6. Can Monel 400 flanges be welded?
Yes. Monel 400 is readily welded by GTAW, GMAW and SMAW using matching Monel filler — ERNiCu-7 (AWS A5.14) bare wire or ENiCu-7 (AWS A5.11) electrodes. No preheat or post-weld heat treatment is required. Joints should be clean and free of sulphur contamination, and interpass temperature kept moderate to preserve corrosion resistance.
Q7. What is the maximum service temperature of Monel 400 flanges?
Monel 400 can be used continuously up to about 480–540 °C depending on environment, and retains useful strength and toughness down to cryogenic temperatures. In steam and many reducing environments it performs well at elevated temperature, but in sulphur-bearing atmospheres the maximum temperature is reduced. It does not embrittle at low temperature, so it also suits cryogenic service.
Q8. Is Monel 400 magnetic?
Monel 400 is weakly magnetic at room temperature, with a Curie temperature around 20–50 °C that depends on exact composition — so it may be slightly magnetic or non-magnetic near ambient. It is not used where guaranteed non-magnetic behaviour is required; for that, fully austenitic stainless or specialised alloys are specified.
Q9. What industries use Monel 400 flanges?
Monel 400 flanges are used in marine and offshore (seawater piping, ballast, firewater), oil & gas refining (HF alkylation, crude overhead, sour service), chemical processing (sulphuric/hydrochloric/hydrofluoric acids, alkalis, chlorinated solvents), desalination, and heat-exchanger and pump/valve connections where chloride or acid resistance is critical.
Q10. Are ASTM B564 Monel 400 flanges supplied with material test certificates?
Yes. Every Monel 400 flange is supplied with EN 10204 3.1 (or 3.2) mill test certificates confirming chemistry, mechanical properties and heat/lot traceability, with PMI (positive material identification), hydrostatic testing and third-party inspection on request. Tesco Steel & Engineering is an ISO 9001:2015 certified manufacturer and exporter from Mumbai, India.