Amigo Impex is a Monel flanges manufacturer, stockist and exporter operating from Mumbai, India, since 2013. Alloy 400 forgings are certified to ASTM B564 / ASME SB-564, while K500 orders are supplied to ASTM B865 / ASME SB-865. Every stage, from cutting and machining through threading, fabrication, testing and packing, is handled in-house.
Monel flanges are nickel-copper alloy flanges containing roughly 67% nickel, with copper making up most of the balance and small additions of iron, manganese, carbon and silicon. This composition provides strong resistance to corrosion in rapidly flowing seawater, brine, hydrofluoric acid and alkaline service. Two grades are supplied in flange form: Monel 400 (UNS N04400) covers most orders, while age-hardened Monel K500 (UNS N05500) is selected where higher mechanical strength is required.
Supply spans NPS 1/2" to 48" (DN 15 to DN 1200). Class 150 to 2500 is available to NPS 12, Class 150 to 1500 to NPS 24, and Class 150 to 900 above that. PN 6 to PN 63 are available for European drawings. Eleven patterns are produced in-house, from weld neck through spectacle blind, with five facing options. Hub patterns are machined from B564 forgings; blind flanges, plate flanges and line blanks are cut from B127 plate. Marine, chemical, oil and gas, and pump and valve installations account for a significant share of the supplied flanges.
As a Monel flanges supplier, Amigo Impex maintains ready stock in Mumbai of 60 to 70 tonnes. An EN 10204 3.1 certificate is supplied with every order, with 3.2 certification available on request. We hold AS 9120B, PED, ISO 9001:2015 and ISO 45001:2018 certifications. Dispatch covers pan-India, while exports reach the USA, the Gulf, Europe and Asia.
Quotations are based on the supply range below. It defines the forging specification for each grade, available sizes and pressure classes, facing and form options, and the certification supplied with finished Monel flanges.
Material requirements and dimensional requirements are governed by separate standards. The grade determines the applicable forging specification, while the nominal bore determines the relevant ASME dimensional standard. National dimensional standards are used when specified on the drawing.
| Category | Standard |
|---|---|
| Nickel-Copper Alloy Forgings | ASTM B564 / ASME SB-564 |
| Age-Hardened Ni-Cu-Al Forgings | ASTM B865 / ASME SB-865 |
| Dimensions, NPS 1/2" to 24" | ASME B16.5 (Monel 400 listed in Table 1A, Group 3.4) |
| Dimensions, NPS 26" to 48" | ASME B16.47 Series A & B dimensional pattern (weld neck and blind). ASME B16.47 excludes nickel base alloys from its material list, so flanges above NPS 24" are machined to the B16.47 pattern and rated by agreement, not marked as B16.47 compliant. |
| Line Blanks and Spacers | ASME B16.48 |
| European Dimensions and PN Ratings | EN 1092-1 |
| Other National Patterns | JIS B2220, IS 6392 |
| Nickel-Copper Alloy Plate, Sheet and Strip | ASTM B127 / ASME SB-127 |
Two grades cover the range, with grade selection depending on the service requirements. Monel 400 is generally selected for corrosion-resistant service, while Monel K500 is preferred where higher mechanical strength is also required.
Monel 400 flanges are commonly used in seawater, brine and hydrofluoric acid service and can be strengthened through cold working.
The aluminium addition enables Monel K500 flanges to be age-hardened to higher tensile and yield strengths than Monel 400 while retaining toughness at cryogenic temperatures.
Nominal bore determines which ASME dimensional standard applies. ASME B16.5 governs NPS 1/2" to 24". Above NPS 24, flanges are machined to the ASME B16.47 Series A or Series B dimensional pattern, with ratings agreed with the purchaser because nickel base alloys sit outside the B16.47 material list. Anything outside the standard sizes below is machined from a forged blank to the supplied drawing.
| Parameter | Range |
|---|---|
| Nominal Bore | NPS 1/2" to 48" |
| Metric Designation | DN 15 to DN 1200 |
| ASME B16.5 Coverage | NPS 1/2" to 24" |
| B16.47 Dimensional Pattern Supplied | NPS 26" to 48", machined to the ASME B16.47 Series A or Series B dimensional pattern. ASME B16.47 itself covers NPS 26 to NPS 60 and excludes nickel base alloys from its material list, so these flanges are rated by agreement. |
| Bore Preparation | Matched to pipe schedule on weld neck and socket weld patterns |
| Non-Standard Drilling | Machined to the drawing supplied |
Pressure class numbers refer to pressure-temperature ratings; they are not equivalent to working pressure in bar. Allowable pressure decreases as metal temperature rises, so design conditions must be checked against the applicable pressure-temperature table for each class and grade.
| Rating System | Standard | Ratings Supplied |
|---|---|---|
| ASME Class, NPS 1/2" to 12" | ASME B16.5 | 150, 300, 600, 900, 1500, 2500 |
| ASME Class, NPS 14" to 24" | ASME B16.5 | 150, 300, 600, 900, 1500 |
| ASME Class, NPS 26" to 48" | B16.47 Series A & B pattern (nickel alloys outside B16.47 material scope) | 150, 300, 600, 900 by agreement |
| PN Rating | EN 1092-1 | PN 6, PN 10, PN 16, PN 25, PN 40, PN 63 |
Eleven patterns cover the flange configurations required for nickel-copper alloy piping systems. Weld neck and blind flanges are the most frequently supplied types, while other configurations are produced against the confirmed bore, pressure class and facing.
Contact Amigo Impex for the current Monel flange price against a confirmed specification.
Request a QuoteThe gasket and mating flange requirements determine the appropriate facing, which is confirmed at the enquiry stage. Five facing options are machined on Monel flange bodies in both grades.
Each machined face receives protective wrapping and a bore cap before the flanges are packed into wooden cases, crates or pallets. Marking covers the grade, size, pressure class, heat number and specification. Domestic orders are dispatched across pan-India, while export consignments ship from Mumbai to the USA, the Gulf, Europe and Asia. Stock items dispatch in 1 to 2 days, while made-to-order forgings require around 30 days.
Chemical analysis, tensile testing, hardness testing and dimensional inspection against the applicable ASME standard are completed in-house before packing. Every order includes an EN 10204 3.1 material test certificate documenting the applicable mill results. 3.2 Certification and third-party inspection are arranged on request. Amigo Impex is certified to AS 9120B, PED, ISO 9001:2015 and ISO 45001:2018.
60–70 tonnes held in Mumbai, with urgent requirements dispatched within one to two days.
AS 9120B, PED, ISO 9001:2015 and ISO 45001:2018, with an MTC on every order.
Cutting, machining, threading, fabrication and testing all handled at our own Mumbai facility.
Original mill certificates plus our own test reports, so every batch can be traced back.
Non-standard sizes and specifications made to order.
Dispatched from Mumbai to every major Indian city, and exported to USA, Gulf, Europe, Asia
Two grades are available in flange form. Monel 400 (UNS N04400) is held in ready stock and is a listed material under ASME B16.5, so standard Class ratings apply. Monel K500 (UNS N05500) is forged to order for higher-strength duty and is supplied to B16.5 dimensions; because K500 is not listed in ASME B16.5 Table 1A, ratings for K500 flanges must be established by the purchaser's design engineer.
ASTM B564 / ASME SB-564 covers Monel 400 flanges, while ASTM B865 / ASME SB-865 covers Monel K500.
Monel flanges are supplied from NPS 1/2" to 48". Class availability depends on bore. Up to NPS 12, Classes 150 through 2500 are available. From NPS 14 to NPS 24, Classes 150 through 1500. From NPS 26 to NPS 48, Classes 150 through 900. EN 1092-1 orders are supplied PN 6 through PN 63.
A raised-face Monel flange concentrates the gasket load on a machined surface above the bolting plane, while a flat-face flange seats a full-face gasket across the entire surface. RF is commonly used for process piping, while FF is suitable for flat-face mating equipment.
No, Monel flanges generally do not require post-weld heat treatment, although requirements depend on the applicable material, welding procedure and service conditions.
For flange service the pressure-temperature ratings in ASME B16.5 govern, and ASME B16.5 requires annealed material only for this group. ASME Section II, Part D tabulates allowable stresses for Monel 400 from -20 °F to 900 °F (-29 °C to 482 °C), which is the basis used for ASME Section VIII, Division 1 equipment. ASME B31.1 (Power Piping) tabulates allowable stresses for Monel 400 only up to 800 °F (427 °C), so power piping designs are held to that lower ceiling. At the cold end, Monel 400 retains ductility and toughness at cryogenic temperatures. The minimum design metal temperature for a given line must be confirmed against ASME B31.3 and the impact-testing rules of para.
Yes, non-standard bores, thicknesses and drilling can be machined to the supplied drawing in either grade, alongside standard ASME B16.5 and B16.47 configurations.
Yes, Amigo Impex exports Monel flanges to the USA, the Gulf, Europe and Asia, with domestic supply from Mumbai and an MTC issued for every consignment.
Nickel-copper flanges are used across eight industries where seawater, brine and acidic service are encountered:
