Monel 400 Flanges

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Product Overview

Om Export India Pvt Ltd is a premier manufacturer, stockist, and global exporter of high-integrity Monel 400 Flanges (ASTM B564 UNS N04400 / Werkstoff 2.4360 / Alloy 400). Monel 400 is a solid-solution nickel-copper alloy containing a minimum of 63% Nickel and 28% to 34% Copper. It provides high resistance to high-velocity seawater, hydrofluoric acid alkylation media, non-oxidizing mineral acids, boiling caustic alkalies, and dry chlorine gases.

Our complete forging and machining line manufactures industrial flanges in compliance with ASME B16.5, ASME B16.47 (Series A & B), ASME B16.36, and EN 1092-1 standards across pressure classes from 150# up to 2500# (PN6 to PN400). Engineered for severe marine piping, subsea risers, crude distillation units, and corrosive chemical processing headers, our Monel 400 flanges maintain high ductility and mechanical toughness from sub-zero cryogenic temperatures up to elevated service temperatures of 1000°F (538°C).

Severe Marine & Caustic Resistance: High resistance to turbulent seawater impingement, cavitation, biofouling, and chloride-induced stress corrosion cracking.
Broad Pressure Capability: Available in ASME Class 150, 300, 600, 900, 1500, and 2500 lbs with Raised Face (RF), Flat Face (FF), and Ring Type Joint (RTJ) facings.
Engineered Integrity: Precision open-die and closed-die forged billets double-melted and precision CNC machined for leak-tight bolted connections.

Key Features

Seawater & Brackish Water Resistance: High resistance to turbulent marine flow, impingement attack, cavitation, and marine biofouling.
Hydrofluoric & Non-Oxidizing Acid Durability: Engineered for severe chemical service involving HF alkylation, hydrochloric, and sulfuric acid streams.
Broad Operating Temperature: Retains impact ductility without embrittlement from cryogenic sub-zero (-200°C) up to 1000°F (538°C).
Stress Corrosion Resistance: Immunity to chloride-ion stress corrosion cracking in high-pressure offshore and chemical environments.
Precise Gasket Serrations: CNC machined phonographic spiral or concentric serrations ensure leak-tight sealing with RTJ, spiral wound, and PTFE gaskets.
Post-Weld Stability: Does not require mandatory post-weld heat treatment (PWHT), saving fabrication turnaround time.

Product Specifications

Specification Parameter	Standard Specification / Technical Value
Nominal Size Range	1/2" NB to 48" NB (DN15 to DN1200 / DN5000 Custom)
Pressure Classes (ASME / ANSI)	Class 150#, 300#, 400#, 600#, 900#, 1500#, 2500# (Per ASME B16.5 / B16.47)
Pressure Ratings (EN / DIN / PN)	PN6, PN10, PN16, PN25, PN40, PN63, PN100, PN160, PN250, PN400 (EN 1092-1)
Flange Face Types	Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), Lap Joint Face (LJF), Male & Female (M&F), Tongue & Groove (T&G)
Governing Standards	ASTM B564, ASME SB564, ASTM B865, ASME B16.5, ASME B16.47, ASME B16.36, EN 1092-1, DIN, JIS, BS
Delivery & Heat Treatment	Annealed & Pickled, Solution Annealed, Precision CNC Machined, Smooth Finish (125–250 AARH/RMS)
Maximum Service Temperature	Continuous service up to 1000°F (538°C); cryogenic capability down to -200°C
Quality Certifications	EN 10204 Type 3.1 & 3.2, NACE MR0175 / ISO 15156, PED 2014/68/EU, 100% PMI Spectro

Dimensions & Sizes

Nominal Pipe Size (NPS)	Flange Outer Diameter (OD mm)	Flange Thickness (C mm)	Raised Face Dia (R mm)	Bolt Circle Dia (PCD mm)	Number of Bolts x Hole Dia
1/2" NB (Class 150#)	88.9 mm (3.50")	11.1 mm (0.44")	34.9 mm (1.38")	60.3 mm (2.38")	4 x 15.9 mm (0.62")
1/2" NB (Class 300#)	95.3 mm (3.75")	14.3 mm (0.56")	34.9 mm (1.38")	66.7 mm (2.62")	4 x 15.9 mm (0.62")
3/4" NB (Class 150#)	98.4 mm (3.88")	12.7 mm (0.50")	42.9 mm (1.69")	69.9 mm (2.75")	4 x 15.9 mm (0.62")
3/4" NB (Class 300#)	117.5 mm (4.62")	15.9 mm (0.62")	42.9 mm (1.69")	82.6 mm (3.25")	4 x 19.1 mm (0.75")
1" NB (Class 150#)	108.0 mm (4.25")	14.3 mm (0.56")	50.8 mm (2.00")	79.4 mm (3.12")	4 x 15.9 mm (0.62")
1" NB (Class 300#)	124.0 mm (4.88")	17.5 mm (0.69")	50.8 mm (2.00")	88.9 mm (3.50")	4 x 19.1 mm (0.75")
1-1/2" NB (Class 150#)	127.0 mm (5.00")	17.5 mm (0.69")	73.0 mm (2.88")	98.4 mm (3.88")	4 x 15.9 mm (0.62")
1-1/2" NB (Class 300#)	155.6 mm (6.12")	20.6 mm (0.81")	73.0 mm (2.88")	114.3 mm (4.50")	4 x 22.2 mm (0.88")
2" NB (Class 150#)	152.4 mm (6.00")	19.1 mm (0.75")	92.1 mm (3.62")	120.7 mm (4.75")	4 x 19.1 mm (0.75")
2" NB (Class 300#)	165.1 mm (6.50")	22.2 mm (0.88")	92.1 mm (3.62")	127.0 mm (5.00")	8 x 19.1 mm (0.75")
2" NB (Class 600#)	165.1 mm (6.50")	25.4 mm (1.00")	92.1 mm (3.62")	127.0 mm (5.00")	8 x 19.1 mm (0.75")
3" NB (Class 150#)	190.5 mm (7.50")	23.8 mm (0.94")	127.0 mm (5.00")	152.4 mm (6.00")	4 x 19.1 mm (0.75")
3" NB (Class 300#)	209.6 mm (8.25")	28.6 mm (1.12")	127.0 mm (5.00")	168.3 mm (6.62")	8 x 22.2 mm (0.88")
3" NB (Class 600#)	209.6 mm (8.25")	31.8 mm (1.25")	127.0 mm (5.00")	168.3 mm (6.62")	8 x 22.2 mm (0.88")
4" NB (Class 150#)	228.6 mm (9.00")	23.8 mm (0.94")	157.2 mm (6.19")	190.5 mm (7.50")	8 x 19.1 mm (0.75")
4" NB (Class 300#)	254.0 mm (10.00")	31.8 mm (1.25")	157.2 mm (6.19")	200.0 mm (7.88")	8 x 22.2 mm (0.88")
6" NB (Class 150#)	279.4 mm (11.00")	25.4 mm (1.00")	215.9 mm (8.50")	241.3 mm (9.50")	8 x 22.2 mm (0.88")
6" NB (Class 300#)	317.5 mm (12.50")	36.5 mm (1.44")	215.9 mm (8.50")	269.9 mm (10.62")	12 x 22.2 mm (0.88")
8" NB (Class 150#)	342.9 mm (13.50")	28.6 mm (1.12")	269.9 mm (10.62")	298.5 mm (11.75")	8 x 22.2 mm (0.88")
8" NB (Class 300#)	381.0 mm (15.00")	41.3 mm (1.62")	269.9 mm (10.62")	330.2 mm (13.00")	12 x 25.4 mm (1.00")

Chemical Composition

Element	ASTM B564 / UNS N04400 (%)	DIN 2.4360 / NiCu30Fe (%)
Nickel (Ni + Co)	63.00 Min	63.00 Min
Copper (Cu)	28.00 – 34.00	28.00 – 34.00
Iron (Fe, Max)	2.50	2.50
Manganese (Mn, Max)	2.00	2.00
Carbon (C, Max)	0.30	0.15
Silicon (Si, Max)	0.50	0.50
Sulfur (S, Max)	0.024	0.020

Mechanical Properties

Material Condition / Temper	Tensile Strength (MPa / ksi)	Yield Strength 0.2% Offset (MPa / ksi)	Elongation in 2 in. (%)	Hardness (Rockwell / Brinell)
Annealed Forging (ASTM B564)	480 – 620 MPa (70 – 90 ksi)	170 – 345 MPa (25 – 50 ksi)	35% – 50%	65 – 85 HRB (110 – 160 HBW)
Hot Finished / As-Forged	520 – 650 MPa (75 – 94 ksi)	240 – 415 MPa (35 – 60 ksi)	30% – 45%	75 – 90 HRB (135 – 185 HBW)
Physical Density & Melting Point	Density: 8.80 g/cm³ (0.318 lb/in³)	Melting Point: 1350°C (2460°F)		Modulus of Elasticity: 105–120 kN/mm²
Expansion & Thermal Properties	Coeff. of Expansion: 13.9 µm/m·°C	Modulus of Rigidity: 65.3 kN/mm²		Service Temp: -200°C to +538°C

Standards & Specifications

Standard Designation	Governing Organization	Scope & Product Type
ASTM B564 / ASME SB564	ASTM / ASME	Standard Specification for Nickel Alloy Forgings (UNS N04400 / UNS N05500)
ASME B16.5	ASME	Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
ASME B16.47 (Series A & B)	ASME	Large Diameter Steel Flanges: NPS 26 through NPS 60 Metric/Inch Standard
ASME B16.36	ASME	Orifice Flanges for Differential Pressure Flow Measurement Systems
EN 1092-1 / DIN Standards	CEN / DIN	Flanges and their joints — Circular flanges for pipes, valves, fittings (PN6 to PN100)
MSS SP-44	MSS Standards	Steel Pipeline Flanges for High-Pressure Hydrocarbon Transmission
NACE MR0175 / ISO 15156	NACE / ISO	Materials for use in H2S-containing environments in oil and gas production

Applications

Monel 400 forged and plate flanges are utilized across demanding marine, oil refining, and chemical processing systems:

Marine & Offshore Engineering: High-pressure seawater cooling manifolds, marine hull penetrations, submarine ballast piping, and offshore splash-zone platform piping.
Chemical Processing Plants: Hydrofluoric acid (HF) alkylation units, fluorination reactor vessel connections, sulfuric acid lines, and caustic soda evaporation systems.
Petroleum Refining & Petrochemicals: Crude oil distillation tower nozzle flanges, overhead vapor lines, sour gas (H2S) gathering piping, and reboiler connections.
Desalination & Power Generation: Multi-Stage Flash (MSF) brine evaporator headers, high-pressure boiler feed pump flanges, and seawater intake isolation valves.
Process Flow Measurement & Isolation: Orifice meter piping runs with Monel orifice flanges, spectacle blinds, spades, and spacers for line blanking.

Frequently Asked Questions

Q1: What are the main benefits of using Monel 400 Weld Neck (WNRF) Flanges?
Monel 400 Weld Neck flanges feature a tapered hub that transfers mechanical and thermal stresses directly to the pipe line, reducing stress concentration at the flange base. This makes them suitable for high-pressure, high-temperature, and sub-zero cyclic services.

Q2: When should Monel 400 Threaded (Screwed) Flanges be selected?
Threaded flanges are assembled without welding, making them suitable for low-pressure services and hazardous, explosive environments (such as hydrocarbon processing areas) where hot work or open flames create safety risks.

Q3: How does Monel 400 resist hydrofluoric acid (HF) in refinery alkylation units?
Monel 400 forms a protective copper-nickel fluoride film in non-aerated hydrofluoric acid environments across all concentrations up to the atmospheric boiling point, preventing localized pitting and stress corrosion cracking.

Q4: What surface finish is applied to the gasket facing of Monel 400 flanges?
In accordance with ASME B16.5, our Raised Face (RF) flanges are precision machined with a serrated concentric or spiral finish having a surface roughness between 125 and 250 µin (3.2 to 6.3 µm Ra) for reliable gasket seating.

Product Overview

Key Features

Product Specifications

Dimensions & Sizes

Chemical Composition

Mechanical Properties

Standards & Specifications

Applications

Frequently Asked Questions

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