Type: UNS N04400 LWN Flange Material: Monel 400 (UNS N04400/Alloy 2.4360) Size: 2″ (DN50) Class / Pressure: 300# Standard: ASME B16.5 Flange Faces: Ring Type Joint (RTJ)
Long weld neck flange(LWN flange) is also call integral flange, it means a welding neck flange has a very long neck. Commonly, the welding neck flange has a tapered neck and a bevel end which is going to butt welding with the matching pipe. But the long weld neck flange, has a straight short pipe as the neck of a long weld neck flange. Long weld neck flange (LWN flange), is used for high pressure situations, integral hub weld neck flanges are used and for very high pressure cases Long Welding Neck flanges are preferred. In this case, the weld are far from the ring to avoid bending stresses and weld stress being combined.
A Ring Type Joint Flange is a type of flange that uses a metal ring that sits in a hexagonal groove as a gasket to seal the flange pair. The flanges seal when the bolts are tightened and the gasket is compressed into the groove making a metal to metal seal. An RTJ flange usually has a raised face with the groove machined into the face of the flange. The raised face doesn’t serve as a way to contain the pressure.
Mechanical Properties of Alloy 400 (UNS N04400/Alloy 2.4360)
0.2% Proof Stress
As Hot Rolled
Physical Properties of Alloy 400 (UNS N04400/Alloy 2.4360)
8,800 kg/m³ @ 20°C
Coefficient of Thermal Expansion
13.9 x 10 -6 / °C (20°C)
21.8 W/m. °C @ 20°C
Thermal Capacity (Specific Heat)
427 J/kg. °C @ 20°C
32 % IACS
0.547 microhm.m @ 20°C
Modulus of Elasticity (tension)
179 GPa @ 20°C
Modulus of Rigidity (torsion)
65.5 GPa @ 20°C
Monel 400 is generally more corrosion resistant that both of the major constituents nickel and copper. It is highly resistant to chlorinated solvents, glass etching agents, sulphuric, hydrofluoric and many other acids, and practically all alkalies. The alloy gives excellent service in sea water under high velocity conditions, where resistance to cavitation and erosion are important. Corrosion rates in strongly agitated and aerated sea water are extremely low. It is generally free from chloride stress corrosion cracking, but only annealed material resists stress cracking in the presence of mercury or mercury salts, and in moist, aerated hydrofluoric acid vapour. It should not be used for nitric acid service. Please consult Austral Wright Metals for specific advice on your application.
AS1210 & ASME Boiler & Pressure Vessel Code pre-qualify Monel 400 for use in pressure vessels up to about 475°C.
Monel 400 can be readily hot worked, with lower forces than many steels. The alloy can easily be cold formed, with forces between those of carbon steel and grade 304 stainless steel.
Monel 400 is easy to machine (class B). Sharp tools, slow speeds and deep uninterrupted cuts to remove the work hardened layer are needed. Monel R-405 is a free cutting version of Monel 400, for rapid production in automatic screw machines. Toughness, strength and corrosion resistance are very similar to Monel 400.
Monel 400 is readily welded by GMAW (MIG), GTAW (TIG), SMAW (manual) and SAW processes. Preheat, post heat and post weld heat treatment are not required. The area around the weld must be clean to prevent contamination of the weld pool. Argon shielding gas is used.
Monel 400 is annealed at 870–980°C, cooling rate not critical. Grain growth is rapid in this alloy, so use the lower end of the temperature range and minimal time to retain good strength. Stress relief, if required, is at 540-570°C. Stress equalising cold worked material at 300°C markedly increases the proof stress, without affecting other properties.
The MONEL 400 alloy is used in the following applications:
Marine fixtures, pumps, valves and piping systems for sea water applications;