Monel 400 Flanges | UNS N04400

Monel 400 flanges refer to pipe flanges made from nickel-copper alloy 400 (UNS N04400/ W.Nr. 2.4360 and 2.4361), which has the nominal designation of 67Ni-30Cu. They have high strength and toughness over a wide temperature range and excellent resistance to many corrosive environments. Monel 400 flanges are widely used in many fields, especially marine and chemical processing.

Chemical Composition Requirements

Physical & Mechanical Properties

A Monel 400 slip on flange (RF), 10″ 900#, ASTM B564 Gr. N04400.

Monel 400 (UNS N04400) flanges offer excellent mechanical properties, including a minimum ultimate tensile strength of 70 ksi (483 MPa) and a minimum yield strength of 25 ksi (172 MPa). The material demonstrates good elongation, with at least 35% in 2 inches or 4 times the specimen diameter, and a reduction of area of 45% minimum. The hardness is usually capped at 150 HB, while its modulus of elasticity is approximately 26,000 ksi. It has the density of 8.8 g/cm³, melting range between 1300-1350°C.

Design Standards & Flange Types

Monel 400 flanges may be manufactured in accordance with a series of international standards including ASME B16.5, ASME B16.47, API 6A, EN1092-1, BS 4504, AS 2129, JIS B2220, GB/T 9112, GB/T 9124, EN ISO 27509, NOSOK L-005. Various flanges types are available such as welding neck, slip on, threaded, blind, socket welding, SO plate, etc.

ASME Applicability

The Monel 400 flange is approved as a material of construction by the ASME Boiler and Pressure Vessel Code. Allowable stresses for Section III construction up to 800°F, Section VIII Division 1 construction up to 900°F and Section VIII Division 2 construction up to 800°F are contained in Tables 1B and 2B of ASME Section II, Part D. The use of these flanges are also approved by ASME B31.3 Process Piping, in which the maximum and minimum application temperatures are 900°F and -325°F, respectively.

Manufacture & Heat Treatment

Monel 400 flanges without hub may be machined directly from ASTM B127 Gr.N04400 plates, while other flanges shall be made from ASTM B564 UNS N04400 forgings. The billet shall be heated up to 1700-2150°F prior to forging. After forging, the solution annealing heat treatment shall be furnished. At 1470°F, Monel 400 is fully annealed.