STAINLESS & DUPLEX PIPING COMPONENTS
Stainless Steel Fittings & Flanges
Specification-controlled sourcing for butt-weld, forged and flanged piping components.
MNK-G.S.A coordinates sourcing of stainless, duplex and high-alloy fittings and flanges by exact material grade, material specification, dimensional standard, nominal size, wall or pressure class, facing, testing, inspection documents and delivery destination.
Material, Dimensions and Pressure Rating Must Be Specified Together
A material designation alone does not define a complete piping component. The purchase requirement must pair the correct ASTM or EN material specification with the applicable ASME, EN or project dimensional standard, then define size, schedule or wall, pressure class or PN, facing, end preparation, testing and documentation.
Material Definition and Supply Scope
Butt-Weld Fittings
Long- and short-radius elbows, equal and reducing tees, concentric and eccentric reducers, caps, returns and special fittings in seamless or welded construction.
Forged Fittings
Socket-weld and threaded elbows, tees, couplings, unions, caps, plugs, bosses and branch fittings sourced by class, end connection and material specification.
Pipe Flanges
Weld-neck, slip-on, blind, lap-joint, threaded, socket-weld, long-weld-neck, reducing and orifice flange configurations where the governing standard supports them.
Austenitic Stainless Families
304/304L, 316/316L, 316Ti, 321/321H, 347, 904L and other austenitic grades supplied only under the specification and product form that explicitly covers the requested designation.
Duplex & Super Duplex
2205, 2507 and other ferritic-austenitic component families sourced with exact UNS or EN designation, solution treatment, corrosion testing and phase-balance requirements where specified.
Project and Custom Components
Non-standard flanges, branch fittings, machined components, welded constructions and complete piping packages can be sourced against approved drawings and design requirements.
Standard Scope and Order Limits
ASME Butt-Weld Fittings
ASME B16.9-2024 covers factory-made wrought butt-weld fittings, NPS 1/2 to 48 (DN 15 to 1200), within its wall-thickness scope. Low-pressure corrosion-resistant fittings under MSS SP-43 are excluded.
ASME Standard Flanges
ASME B16.5-2025 covers flanges from NPS 1/2 through NPS 24 in Classes 150, 300, 400, 600, 900 and 1500; Class 2500 is covered through NPS 12.
ASME Large-Diameter Flanges
ASME B16.47 covers NPS 26 through NPS 60 in Classes 75, 150, 300, 400, 600 and 900. Series, facing and material must be stated explicitly.
European PN Flanges
EN 1092-1 defines PN-designated circular steel flanges. The required DN, PN, flange type, facing, bore and matching pipe dimensions are confirmed as one order specification.
Forged Fitting Classes
ASME B16.11-2021 defines threaded fittings in Classes 2000, 3000 and 6000 and socket-weld fittings in Classes 3000, 6000 and 9000. Available size depends on fitting type and class.
Special and Engineered Sizes
Specialist forging and fabrication routes can extend beyond standard catalogue dimensions, but no maximum is promised without confirmation of grade, pressure basis, geometry, weight, heat treatment, testing and drawing approval.
Standards and Documentation
ASTM A182/A182M-26a
Material specification for forged or rolled alloy and stainless steel pipe flanges, forged fittings, valves and parts for high-temperature service within its defined grades and product limits.
ASTM A403/A403M-26a
Material specification for wrought austenitic stainless steel fittings for pressure piping, including defined WP and CR grades and construction classes.
ASTM A815/A815M-26
Material specification for wrought ferritic, ferritic-austenitic and martensitic stainless steel piping fittings, including duplex families within its defined grades and classes.
ASME B16.9 / B16.11
B16.9 controls factory-made wrought butt-welding fitting dimensions and related requirements; B16.11 controls forged socket-weld and threaded fitting ratings, dimensions, tolerances and marking.
ASME B16.5 / B16.47
B16.5 and B16.47 define different flange scopes. Confirm the applicable size, rating class, product type and series; do not apply a flange size range automatically to every flanged fitting.
EN 10253-4:2025 / EN 1092-1:2018
EN 10253-4 covers wrought austenitic and duplex butt-welding fittings with specific inspection requirements; EN 1092-1 covers PN-designated circular steel flanges. Inspection documentation is agreed under EN 10204:2004 where applicable.
Application Context
Water and Wastewater
Fittings, flanges and replacement piping components for treatment plants, pumping stations, utilities and EPC packages under the project material and pressure specification.
Process, Chemical and Food Systems
Corrosion-resistant piping components selected against process medium, pressure, temperature, cleanliness, fabrication and inspection requirements.
Marine, Energy and Industrial MRO
Small and medium replacement lots, urgent shutdown requirements and project packages for ship repair, energy equipment and industrial maintenance.
Capability Note
The ranges above describe standard scopes, not guaranteed MNK stock or one manufacturer’s complete programme. Confirm grade, component type, size, wall thickness, pressure-temperature basis, facing, condition, tolerances and quantity together. A Class or PN designation alone does not establish suitability for the operating conditions.
Relevant EN Product-Form References
These references support order preparation by product form. The current authorised standard, material grade, edition, design code and project documents must be verified before quotation.
Bolting References for Flanged Assemblies
For pressure-equipment and piping assemblies, bolt/stud and nut specifications must be paired with the flange, gasket, design code, service temperature, preload procedure and required inspection documents.
Relevant ISO References
Use the current authorised edition together with the governing product specification, project requirements and inspection documents. A standards reference does not establish automatic grade equivalence or product approval.
Send Your Stainless Steel Fittings & Flanges Inquiry
Provide the material grade or composition, governing specification, product form, complete dimensions, quantity, inspection-document requirements and delivery destination.
Special Bolting for Pressure and Flange Service
Pressure-service assemblies require compatible bolting, nuts, threads, grades, service conditions and documentation under the governing equipment or piping code.
Sources and scope checked
Source review date:
Review limits: The nine references below were checked against public publisher descriptions. This review covers their identity, edition and stated scope, not every grade, chemical limit, pressure-temperature rating, bolting reference or product approval on this page. Use the authorised standard and project specification for purchasing and design; no full standard tables are reproduced.
- ASME B16.9-2024
Factory-made wrought butt-weld fittings: NPS 1/2–48 (DN 15–1200), any producible wall thickness within scope. Low-pressure corrosion-resistant fittings covered by MSS SP-43 are excluded.
- ASME B16.5-2025
Flanges: NPS 1/2–24 in Classes 150, 300, 400, 600, 900 and 1500; Class 2500 through NPS 12. Separate scope limits apply to flanged fittings.
- ASME B16.47-2025
Large-diameter steel flanges: NPS 26–60, Classes 75, 150, 300, 400, 600 and 900. Specify the applicable series, facing and material.
- ASME B16.11-2021
Forged fittings: threaded Classes 2000, 3000 and 6000; socket-weld Classes 3000, 6000 and 9000. Confirm size and fitting type against the standard.
- ASTM A182/A182M-26a
Forged low-alloy and stainless pressure-system components, including flanges, fittings and valves. Grade, heat treatment, dimensional basis and product limits must be specified; bar-machined products are not automatically covered.
- ASTM A403/A403M-26a
Wrought austenitic stainless fittings for pressure piping. WP/CR grades and construction or examination classes must match the order.
- ASTM A815/A815M-26
Wrought ferritic, ferritic-austenitic and martensitic stainless piping fittings. Confirm the WP/CR grade and seamless or welded construction requirements.
- EN 10253-4:2025
BSI catalogue entry for butt-weld fittings in wrought austenitic and austenitic-ferritic duplex stainless steels, with specific inspection requirements.
- EN 1092-1:2018
BSI catalogue entry for PN-designated circular steel flanges. Confirm DN, PN, flange type and facing together rather than treating every combination as available.