Long Weld Neck Flange Manufacturer, Supplier & Exporter
A long weld neck flange (LWN or LWNF), also called a nozzle flange, is a weld neck flange with a long, straight neck in place of the usual short tapered hub. Raaj Fittings manufactures and exports long weld neck flanges in stainless steel, duplex, nickel alloys, carbon steel and alloy steel, with flange dimensions and drilling to ASME B16.5 and other standards.
The extended neck is welded directly into a vessel, column, tank or heat exchanger shell, forming the nozzle and the flange in one forged piece. This removes the separate pipe-to-flange weld, reduces fabrication time and gives a stronger, more reliable nozzle than one built up from pipe and a standard weld neck flange.
All long weld neck flanges are supplied with EN 10204 3.1 mill test certificates, with 3.2 certification and third-party inspection on request.
We export long weld neck flanges to EPC contractors, refineries and stockists across the Middle East and GCC, Europe and the Americas, made to the ASME, EN or DIN standard your project specifies, with PED-compliant supply for European projects on request.
Long Weld Neck Flange Specifications
Flange ring, bolt circle and drilling to ASME B16.5 (other standards on request)
½" NPS to 24" NPS (larger sizes to order)
ASME Class 150, 300, 600, 900, 1500 and 2500
Heavy Barrel (HB) and Equal Barrel (E) — straight neck of uniform thickness
Standard lengths of 9", 12" and 15", or to the length shown on the vessel drawing
Forged as one piece, heat treated as required, and CNC machined
EN 10204 3.1 mill test certificate as standard; EN 10204 3.2 on request
Materials & Grades
We supply long weld neck flanges in the following materials and grades. All grades are supplied with EN 10204 3.1 / 3.2 Mill Test Certificates.
Stainless Steel Long Weld Neck Flanges
Stainless steel flanges offer excellent corrosion resistance and are essential in chemical, pharmaceutical, food processing, and marine environments.
(ASTM A182 F304 / F304L) General corrosion resistance
(ASTM A182 F316 / F316L) Superior resistance to chlorides, acids; marine & pharmaceutical service
(ASTM A182 F316H) High-temperature elevated creep strength
(ASTM A182 F321) Titanium-stabilized; suitable for sustained elevated temperatures
(ASTM A182 F347) Columbium-stabilized; used in heat exchangers and high-temperature piping
High alloy; exceptional resistance to strong acids
Duplex & Super Duplex Stainless Steel Long Weld Neck Flanges
Duplex and super duplex grades offer approximately twice the yield strength of standard austenitic stainless steel, combined with excellent resistance to stress corrosion cracking and pitting — making them ideal for offshore, subsea, and chemical processing.
(UNS S31803 / S32205) Used in offshore platforms and chemical processing plants
(UNS S32750) Ideal for seawater handling and desalination systems
(UNS S32760) Designed for high-chloride offshore service applications
Nickel Alloy Long Weld Neck Flanges
For the most aggressive corrosive environments — including concentrated acids, caustic solutions, sour gas service, and extreme temperatures — we offer flanges in a full range of nickel alloys.
(UNS N06600) High-temperature oxidation resistance
(UNS N06625) Outstanding corrosion resistance for offshore and subsea service
(UNS N08825) Excellent resistance to phosphoric and sulfuric acids
(UNS N10276) Broad-spectrum corrosion resistance in acids and chlorides
(UNS N06022) Superior resistance to oxidizing acids
(UNS N04400) Suitable for seawater, hydrofluoric acid, and marine environments
(UNS N08020) Engineered for sulfuric acid service
Exceptional corrosion resistance with low weight
(C70600 / C71500) Preferred for marine and seawater piping systems
Carbon Steel Long Weld Neck Flanges
Carbon steel is the standard choice for general-purpose, non-corrosive, and elevated-temperature services. The primary grade for forged carbon steel flanges is ASTM A105, and for low-temperature service, ASTM A350 LF2.
Primary grade for forged carbon steel fittings and flanges — covers ambient and elevated-temperature service in pressurised piping systems.
Low-temperature carbon steel, impact-tested for service down to -46°C (-50°F) — LNG, cold climate, and cryogenic piping applications.
Alloy Steel Long Weld Neck Flanges
Alloy steel flanges are specified for high-temperature, high-pressure service in power generation, petrochemical, and refinery applications.
(5% Cr, ½% Mo) Designed for elevated temperature refinery service
(9% Cr, 1% Mo) Suitable for high-temperature steam and hydrogen service
(1¼% Cr, ½% Mo) Widely used in thermal power plant piping systems
(2¼% Cr, 1% Mo) Used in high-temperature pressure vessels and reactors
(9% Cr, 1% Mo, V, Nb) Engineered for ultra-high-temperature power plant steam lines
Long Weld Neck vs Standard Weld Neck
A standard weld neck flange has a short tapered hub that is butt-welded to a pipe. A long weld neck replaces the hub and the pipe with one extended forged neck, which is set into the vessel shell and welded there. The flange end then bolts to the connecting pipework, an orifice assembly, an instrument or a blind flange.
- One-piece nozzle — no pipe-to-flange weld, so less welding, radiography and fabrication time.
- Heavy wall — the thick neck reinforces the shell opening and resists external nozzle loads.
- Forged integrity — the grain flow of a forging gives better toughness than a fabricated nozzle.
Heavy Barrel and Equal Barrel
In a Heavy Barrel (HB) long weld neck the neck wall is thicker, with a bore smaller than the connecting pipe; it is used where the nozzle carries high loads or must provide shell reinforcement. In an Equal Barrel (E) long weld neck the neck has an equal outside and inside diameter along its whole length, giving a constant wall thickness. The bore of either type can be machined to suit the connecting pipe schedule.
Ordering Information
Please give the size, pressure class, facing, material grade, neck type (HB or E), neck length, bore diameter and any weld-end preparation shown on your vessel or exchanger drawing.
Applications & Industries
- Nozzles on pressure vessels, reactors and distillation columns
- Heat exchanger shell and channel nozzles
- Storage tank and separator connections
- Thermowell and instrument connections in thick-walled equipment
- Refinery, petrochemical, fertiliser and power plant equipment
- Offshore process vessels in duplex and super duplex
See all flange types we manufacture.
Testing, Inspection, Marking & Packing
Long weld neck flanges are produced under our quality assurance process:
- Incoming material verification with PMI testing
- Chemical and mechanical testing to the applicable ASTM material specification
- Heat treatment as required, with pickling and passivation for stainless steels
- Dimensional inspection of neck length, bore, outside diameter, bolt circle and facing
- Marking with grade, size, class and heat number for full traceability
Supplied with EN 10204 3.1 mill test certificates; EN 10204 3.2 certificates and third-party inspection are available on request.
Flanges are packed for export with gasket faces protected by covers, rust-preventive coating on carbon and alloy steel, and seaworthy wooden cases; marking, tagging and packing to your specification are available on request.
Why Choose Raaj Fittings for Long Weld Neck Flanges?
Raaj Sagar Steels has supplied piping components since 2003 and today manufactures flanges at two plants in India for buyers in the Middle East, Europe and the Americas.
- Manufactured in-house — Long weld neck flanges are made in our own plants, so material, dimensions and delivery stay under our control.
- Ready stock, short lead times — common sizes and grades are held in stock for prompt dispatch; other sizes, grades and specials are manufactured to order.
- Certified quality — ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 certified; PED 2014/68/EU and IBR supply available, and NACE MR0175 / ISO 15156 material on request.
- 100% material verification — PMI testing on incoming material and EN 10204 3.1 mill test certificates with every order; 3.2 certificates on request.
- Third-party inspection ready — we regularly work with SGS, Bureau Veritas, TÜV and DNV.
- Export documentation — MTCs, certificates of origin, packing lists and inspection reports to suit projects in the GCC, Europe and the Americas.
- Export packing — seaworthy packing with end and face protection, and packing to your specification on request.
- Fast response — our team replies to enquiries within one business day.
Long Weld Neck Flanges — FAQs
A long weld neck flange is a weld neck flange with an extended straight neck instead of a short tapered hub. The neck is welded into a vessel or equipment shell, so the flange and nozzle are one forged piece.
They are used as nozzles on pressure vessels, columns, reactors, heat exchangers and tanks, and for thermowell and instrument connections in thick-walled equipment.
A heavy barrel (HB) neck has a thicker wall and smaller bore, giving extra strength and reinforcement. An equal barrel (E) neck has a constant wall thickness along its length. Your vessel design specifies which is required.
Common neck lengths are 9", 12" and 15", and we also make long weld necks to the exact length shown on the equipment drawing.
The flange ring, bolt circle, drilling and facing follow ASME B16.5 (or another flange standard), while the neck length, bore and type are set by the purchaser or the vessel design.
Yes. We supply long weld neck flanges for projects under the European Pressure Equipment Directive (PED 2014/68/EU), and with IBR certification for Indian boiler applications. NACE MR0175 / ISO 15156 compliant material is also available on request for sour service in the Middle East and the Americas.
